JP2008061617A - Working vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem of a working vehicle, that the control of automatic vehicle velocities can hardly be performed in response to working states, the tastes of operators or the like, because a constant waiting time period is always set in a period from a previous reduction operation finish time to the next return increase operation start time. <P>SOLUTION: This working vehicle comprises a rack position sensor 200 for detecting the amount of a supplied fuel from a rack position of a fuel injection pump 199, a controller 190 for performing the automatic vehicle velocity control, and a waiting time-setting device 98 for manually setting a waiting time period Tw from a previous reduction operation finish time to the next return increase operation start time. The controller 190 controls to finish the previous reduction operation and then perform the next return increase operation through the waiting time period Tw preliminarily set to the waiting time-setting device 98. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a work vehicle such as an agricultural working machine such as a combine, and more particularly to a configuration for executing vehicle speed control of the work vehicle.

  Conventionally, in a combine as a work vehicle, power from an engine mounted on a traveling machine body is appropriately shifted by a hydraulic drive means, and this shift output is transmitted to a working unit such as a mowing unit or a threshing unit and a traveling unit. It is configured to communicate separately. It is known to perform constant rotation control (isochronous control) that keeps the engine speed substantially constant even when the engine load fluctuates depending on the combine working state, crop conditions, and the like (for example, Patent Document 1). reference). Such constant rotation control is performed in a range where the engine load does not exceed a predetermined value.

Further, in Patent Document 1, in order to avoid stopping the engine when the engine is overloaded, the vehicle speed of the traveling machine body is reduced by a predetermined ratio or a predetermined amount when the engine load exceeds a predetermined value (overload). It is also disclosed that vehicle speed control is performed in which when the engine overload is resolved, the vehicle speed of the traveling machine body is restored and increased to the original vehicle speed before deceleration.
JP 10-339181 A

  By the way, in the above-mentioned vehicle speed control, it is general to set so as to always wait for a certain time interval (time lag) from the end of the previous deceleration operation to the start of the next return acceleration operation. It is.

  For this reason, if the predetermined time interval is too short, the switching from the previous deceleration operation to the next return acceleration operation will be abrupt, and the traveling aircraft will proceed in a state close to so-called hunting. The ride is bad. On the other hand, if the predetermined time interval is too long, the switching from the previous deceleration operation to the next return acceleration operation is delayed, which may hinder smooth execution of the mowing and threshing operation.

  In short, when the time interval from the end of the previous deceleration operation to the start of the next return acceleration operation is always constant, it is difficult to execute the vehicle speed control in accordance with the work situation and the operator's preference.

  Therefore, the present invention has a technical problem to provide a work vehicle that solves the above-described problems.

  In order to solve this technical problem, the work vehicle according to the invention of claim 1 is configured to transmit the power from the engine mounted on the traveling machine body to the working unit and the traveling unit via the hydraulic drive means. Configured to detect the load of the engine in relation to the fuel supply means to the engine, and when the engine is overloaded, the vehicle speed of the traveling vehicle body is reduced, and the overload is eliminated. Vehicle speed control means for executing vehicle speed control for returning and increasing the vehicle speed of the traveling machine to the original vehicle speed before deceleration, and from the end of the previous deceleration operation to the start of the next recovery acceleration operation in the vehicle speed control Standby time setting means for manually setting the standby time of the vehicle, wherein the vehicle speed control means is set in advance by the standby time setting means after the previous deceleration operation is completed. After passing through, and to control so as to perform the following recovery acceleration operation.

  A work vehicle according to a second aspect of the present invention is configured to transmit power from an engine mounted on a traveling machine body to a working unit and a traveling unit via a hydraulic drive unit. Load detecting means for detecting the load of the engine in relation to the fuel supply means; and when the engine is overloaded, the vehicle speed of the traveling vehicle body is repeatedly decelerated until the overload is eliminated, and when the overload is eliminated, the traveling Vehicle speed control means for executing vehicle speed control for returning and increasing the vehicle speed to the original vehicle speed before deceleration, and starting the next deceleration operation or return acceleration operation from the end of the previous deceleration operation in the vehicle speed control. Standby time setting means for manually setting the standby time until the time point, and the vehicle speed control means is preset by the standby time setting means after the previous deceleration operation is completed. After passing through the set waiting time, and to control so as to perform the following deceleration or return acceleration operation.

  According to a third aspect of the present invention, in the work vehicle according to the first or second aspect, load factor setting means for manually setting a set engine load factor as a threshold value corresponding to when the engine is overloaded is further provided. And the vehicle speed control means determines that the engine is overloaded and decelerates the vehicle speed of the traveling vehicle body when an engine load factor obtained from detection information of the load detector exceeds the set load factor. On the other hand, when the engine load factor is equal to or less than the return load factor determined according to the value of the set engine load factor, it is determined that the engine overload has been resolved and the vehicle speed of the traveling vehicle body is reduced to the original vehicle speed before deceleration. The control is performed so that the return speed is increased up to.

  According to the first and second aspects of the invention, the standby time setting means for manually setting the standby time from the end of the previous deceleration operation to the start of the next return acceleration operation (or deceleration operation) in the vehicle speed control. The vehicle speed control means performs the next return acceleration operation (or deceleration operation) after a preset standby time set in advance by the standby time setting means after the previous deceleration operation is completed. Therefore, by setting the standby time setting means, the set standby time from the end of the previous deceleration operation in the vehicle speed control to the start of the next return acceleration operation (or deceleration operation) is set. Easy to change and adjust.

  For this reason, when the mowing and threshing operation is desired to be performed as quickly as possible (smoothly), the set waiting time can be shortened, and the traveling body is prevented from proceeding in a state close to hunting to improve ride comfort and driving safety. When it is desired to achieve the above, the set waiting time can be lengthened. That is, there is an effect that the vehicle speed control can be executed in a state according to the work situation or the operator's preference.

  According to a third aspect of the present invention, the vehicle further comprises load factor setting means for manually setting a set load factor as a threshold value corresponding to when the engine is overloaded. When the engine load factor obtained from the detection information of the load detection means becomes equal to or higher than the set load factor, the engine is judged to be overloaded and the vehicle speed of the traveling machine body is reduced, while the engine load factor is set to the set value. If it becomes less than the return load factor determined according to the value of the load factor, it is determined that the engine overload has been resolved, and the vehicle speed of the traveling machine body is controlled to return to the original vehicle speed before deceleration and to increase the speed. A reference value for determining whether or not the engine is in an overload state, that is, whether or not the vehicle speed of the traveling machine body is forcibly decelerated can be adjusted by setting the load factor setting means.

  For this reason, when executing the vehicle speed control, it is possible to easily adopt an appropriate setting in accordance with the work situation, the operator's preference, and the like. Also in this respect, the vehicle speed control can be optimized.

  Note that, by adopting a configuration in which the return load factor corresponding to this value is automatically determined when the set load factor is determined, the labor for manual setting of the return load factor is saved. In this respect, it contributes to the suppression of the operation burden on the operator.

  Hereinafter, an embodiment embodying the present invention will be described with reference to the drawings (FIGS. 1 to 14) when applied to a normal combine as a work vehicle. 1 is a side view of the combine, FIG. 2 is a skeleton diagram showing a traveling drive system of the combine, FIG. 3 is a plan view of a control unit, FIG. 4 is a perspective view of a side column, and FIG. 5 is a main shift lever and a steering handle. FIG. 6 is a front view showing the relationship between the detent means, the linkage mechanism, and the electric motor. FIG. 7 is a sectional view taken along the line VII-VII in FIG. 8A is a diagram showing a state in which the straight detent rod is rotated in the forward acceleration direction, and FIG. 8B is a diagram in which the sector gear and the relay arm are rotated to the maximum forced deceleration position by driving the electric motor. FIG. 9C is a diagram showing a state in which the sector gear and the relay arm are returned to their initial positions by driving the electric motor, FIG. 9 is a functional block diagram of the controller, and FIG. Control map diagram showing the relationship with deceleration amount 11 is a flowchart showing an example of the vehicle speed control, FIG. 12 is a time chart showing an example of the vehicle speed control, FIG. 13 is a flowchart showing another example of the vehicle speed control, and FIG. 14 shows another example of the vehicle speed control. It is a time chart.

(1). First, a schematic structure of a combine will be described with reference to FIG.

  The ordinary combine in the embodiment includes a traveling machine body 1 supported by a pair of left and right traveling crawlers 2 as traveling portions. At the front part of the traveling machine body 1, a cutting part 3 for taking in planted cereal grains such as rice, wheat and soybeans is mounted by a single-acting hydraulic cylinder 4 so as to be adjustable up and down.

  A cabin-type control unit 5 is mounted on the front side of the traveling machine body 1 (in the embodiment, the front right side). Behind the control unit 5, a diesel engine 6 (see FIG. 2) as a power source and a grain tank 7 for storing the grain after threshing are arranged.

  On the other side of the traveling machine body 1 (left side in the embodiment), a threshing unit 8 for threshing the harvested cereals sent from the harvesting unit 3 is mounted. Below the threshing unit 8, a sorting unit 9 for performing swing sorting and wind sorting is arranged.

  The left and right traveling crawlers 2 serving as traveling units include a plurality of driving wheels 11 and driven wheels 12 disposed at the front and rear ends of the longitudinal longitudinal track frame 10 below the traveling machine body 1 and a longitudinal middle portion of the track frame 10. The rolling wheel 13 arranged individually and the crawler belt 14 wound around the outer periphery of the wheels 11 to 13 are provided. The left and right crawler belts 14 are rotated around the wheels 11 to 13 by rotating the left and right drive wheels 11 with power from a drive output shaft 60 (see FIG. 2) that protrudes left and right outward from a mission case 30 described later. Is configured to be driven in rotation.

  The mowing unit 3 includes a rectangular tubular feeder house 15 that communicates with the front opening of the threshing unit 8, and a horizontally long bucket-shaped platform 16 that is connected to the front end of the feeder house 15. A lower surface portion of the feeder house 15 and a front end portion of the traveling machine body 1 are connected via a single-acting hydraulic cylinder 4.

  A lateral feed auger 17 is rotatably supported in the platform 16. A scraping reel 18 with a tine bar is disposed above the front portion of the lateral feed auger 17. A horizontally long clipper-shaped cutting blade 19 is disposed on the lower surface side of the platform 16. A pair of left and right weed bodies 20 project from the front portion of the platform 16.

  The planted cereals that have been pulled back by the scraping reel 18 are harvested by the cutting blade 19, and then collected in the vicinity of the central portion of the platform 16 by the rotational drive of the lateral feed auger 17. The collected cereal grains are sent to the threshing unit 8 via the chain conveyor 21 in the feeder house 15.

  In the handling room of the threshing unit 8, a front and rear longitudinal handling cylinder 22 for threshing the harvested cereal meal is built. Although not shown in detail, screw blades having a plurality of incisors are spirally wound around the outer peripheral surface of the handle 22. The harvested cereal mash that has been conveyed into the handling chamber is finely cut by each incisor of the handling cylinder 22.

  The sorting unit 9 disposed below the threshing unit 8 includes a swing sorting device 23 having a receiving net, a chaff sheave, and the like, and a wind sorting device 24 having a Kara fan or the like. The grains that have leaked from the receiving net are used as the first thing such as fine grains, the second thing such as the grain with branches, and the waste (swarf) by the swing sorting device 23 and the wind sorting device 24. Selected.

  After the sorting by the swing sorting device 23 and the wind sorting device 24, the first thing such as the fine particles collected in the first receiving bowl at the lower part of the traveling machine body 1 is the first conveyor 25 and the cereal conveyor (not shown). To the grain tank 7. A second thing such as a grain with a branch is returned to the handling room via the second conveyor 26, the reduction conveyor 27, and the like, and threshed again by the handling cylinder 22. The second item after the threshing is re-sorted by the sorting unit 9. The waste and the like are finely cut by a spreader 28 disposed below the rear portion of the threshing portion 8 and then discharged to the rear of the traveling machine body 1.

  The grain in the grain tank 7 is carried out to the loading platform of the transport truck (outside the traveling machine body 1) via the discharge auger 29 erected at the rear part of the traveling machine body 1.

(2). Next, the traveling drive system of the combine will be described with reference to FIG.

  In the ordinary combine according to the embodiment, the power from the engine 6 is appropriately shifted by the hydraulic drive means 31 in the mission case 30 and the right and left are output via the drive output shafts 60 projecting left and right outward from the mission case 30. It is configured to output to the drive wheel 11.

  In this case, in the transmission case 30, a hydraulic drive means 31 for shifting the power from the engine 6, a sub-transmission mechanism 32 having low speed, medium speed, high speed and neutral speed stages, and a pair of left and right A differential gear mechanism 33 having a planetary gear mechanism 51 and the like is incorporated.

  Power from the engine 6 is transmitted from the output shaft 34 of the engine 6 to the hydraulic drive means 31 via a pulley and a belt transmission system. The hydraulic drive means 31 includes a straight traveling HST transmission mechanism 35 including a first hydraulic pump 36 and a first hydraulic motor 37, and a turning HST transmission mechanism 38 including a second hydraulic pump 39 and a second hydraulic motor 40. It has.

  Power from the output shaft 34 toward the hydraulic drive means 31 is transmitted to the common pump shaft 41 of both the hydraulic pumps 36 and 39 outside the transmission case 30. In both the straight travel and turning HST transmission mechanisms 35 and 38, hydraulic oil is sent from the hydraulic pumps 36 and 39 to the hydraulic motors 37 and 40 by the power transmitted to the common pump shaft 41.

  In the straight traveling HST type transmission mechanism 35, the inclination angle of the rotary swash plate of the first hydraulic pump 36 is changed and adjusted in accordance with the shift position of a main transmission lever 77 (details will be described later) arranged in the control unit 5. Then, by changing the discharge direction and discharge amount of the hydraulic oil to the first hydraulic motor 37, the rotation direction and the rotation speed of the linear motor shaft 42 protruding from the first hydraulic motor 37 are arbitrarily adjusted. It is configured.

  The rotational power of the linear motor shaft 42 in the first hydraulic motor 37 is transmitted from the linear output gear 43 fixed to the linear motor shaft 42 to the auxiliary transmission mechanism 32 via the transmission gear mechanism 44. The rotational power of the linear motor shaft 42 is also branched and transmitted to the PTO shaft 46 having the clutch means 47 via the output gear 45. Although details are not shown, it is configured to drive working units such as the mowing unit 3 and the threshing unit 8 by the rotational power branched to the PTO shaft 46.

  The sub-transmission mechanism 32 includes a conventionally known gear mechanism, and the rotational power (rotation) from the linear motor shaft 42 is operated by operating a sub-transmission lever 78 (details will be described later) disposed in the control unit 5. The range of adjustment of the direction and the number of rotations) is set so that it can be switched to four speed stages, low speed, medium speed, high speed, and neutral. A brake shaft 48 which is a component of the auxiliary transmission mechanism 32 is provided with a brake means 49 such as a wet multi-disc disk. In the embodiment, a vehicle speed sensor 197 such as a rotary encoder for detecting the vehicle speed of the traveling machine body 1 is provided in association with the brake shaft 48.

  The rotational power from the auxiliary transmission mechanism 32 is transmitted to the differential gear mechanism 33 from the auxiliary transmission output gear 50 fixed to the brake shaft 48. A pair of left and right planetary gear mechanisms 51, which are constituent elements of the differential gear mechanism 33, are formed symmetrically, and a pair of left and right carriers that rotatably support a plurality of planetary gears 53 on the same radius. 52. These two carriers 52 are arranged so as to oppose each other at an appropriate interval on the same axis.

  A center gear 55 is fixed to the center of the sun shaft 54 located between the left and right carriers 52. The center gear 55 meshes with the auxiliary transmission output gear 50 on the auxiliary transmission mechanism 32 side. Sun gears 56 are fixed to the left and right sides of the sun shaft 54 with the center gear 55 interposed therebetween. Each sun gear 56 meshes with each planetary gear 53 of the carrier 52 corresponding thereto. The left and right ends of the sun shaft 54 are rotatably supported by bearings (not shown) located at the rotation center of each carrier 52.

  A pair of left and right ring gears 57 having inner teeth on the inner peripheral surface and outer teeth on the outer peripheral surface are arranged concentrically with the sun shaft 54 so that the inner teeth mesh with the plurality of planetary gears 53. . Each ring gear 57 is pivotally supported by a carrier shaft 58 projecting left and right outward from the outer surface of the carrier 52 via a bearing (not shown).

  Rotational power from the auxiliary transmission output gear 50 in the auxiliary transmission mechanism 32 is transmitted to the left and right planetary gear mechanisms 51 via a center gear 55 fixed to the sun shaft 54. The rotational power transmitted to the left and right planetary gear mechanisms 51 is output from the carrier shaft 58 of each carrier 52 to the left and right drive output shafts 60 via the transmission gear mechanism 59.

  On the other hand, in the turning HST type transmission mechanism 38, the inclination angle of the rotary swash plate of the second hydraulic pump 39 according to the amount of turning operation of the steering handle 73 (details will be described later) arranged in the control unit 5. And adjusting the rotation direction and the rotation speed of the turning motor shaft 61 protruding from the second hydraulic motor 40 by changing the discharge direction and discharge amount of the hydraulic oil to the second hydraulic motor 40. Is configured to do.

  The rotational power of the turning motor shaft 61 in the second hydraulic motor 40 is transmitted from the turning output gear 62 fixed to the turning motor shaft 61 to the pair of left and right rotating gears 64 via the gear mechanism 63. The left rotation gear 64 meshes with the external teeth of the left ring gear 57 via the reverse rotation gear 65. The right rotation gear 64 directly meshes with the external teeth of the right ring gear 57. Accordingly, when the left ring gear 57 rotates forward at a predetermined rotational speed by the forward rotation of the second hydraulic motor 40, the right ring gear 57 rotates backward at the same rotational speed as the left ring gear 57.

  According to such a configuration, for example, if the driving of the turning HST transmission mechanism 38 is stopped, the left and right ring gears 57 are in a locked state (fixed state) in which they cannot rotate. At this time, the turning motor shaft 61 of the second hydraulic motor 40 is preferably locked (fixed) by a brake means 66 such as a wet multi-plate disk.

  When the straight HST transmission mechanism 35 is driven in a state where the driving of the turning HST transmission mechanism 38 is stopped, it is transmitted from the straight output gear 43 of the linear motor shaft 42 to the center gear 55 of the sun shaft 54. Rotational power is transmitted to the left and right sun gears 56 at the same rotational speed, and is output to the left and right drive output shafts 60 and thus to the drive wheels 11 at the same direction and the same rotational speed via the left and right planetary gears 53 and the carrier 52. . As a result, the traveling machine body 1 travels straight. In this case, the traveling machine body 1 moves forward when the linear motor shaft 42 is driven in the forward rotation direction, and the traveling machine body 1 moves backward when driven in the reverse rotation direction.

  Conversely, when the driving of the straight traveling HST transmission mechanism 35 is stopped, the sun shaft 54 and the left and right sun gears 56 are in a locked state (fixed state) where they cannot rotate. Also at this time, it is preferable to lock (fix) the linear motor shaft 42 of the first hydraulic motor 37 by the brake means 67 such as a wet multi-plate disk.

  When the turning HST transmission mechanism 38 is driven in a state where the driving of the straight traveling HST transmission mechanism 35 is stopped, the rotational power from the turning motor shaft 61 is transmitted via the left rotation gear 64 and the reverse rotation gear 65. The left ring gear 57 is rotated forward (reverse) at a predetermined rotational speed, while the right ring gear 57 is rotated reversely (forward) at the same rotational speed as the left ring gear 57 via the right rotational gear 64.

  The forward (reverse) direction rotational power transmitted to the left ring gear 57 rotates the left drive output shaft 60 and thus the left drive wheel 11 in the forward (reverse) direction via the left planetary gears 53 and the carrier 52. . The rotational power in the reverse (forward) direction transmitted to the right ring gear 57 rotates the right drive output shaft 60 and thus the right drive wheel 11 in the reverse (forward) direction via each planetary gear 53 and carrier 52 on the right side. .

  In other words, the rotational power from the turning HST transmission mechanism 38 is transmitted to the left and right planetary gear mechanisms 51 so as to apply rotational forces in opposite directions, and one of the drive wheels 11 of the left and right traveling crawlers 2 moves forward. The traveling machine body 1 spin-turns on the spot.

  Further, when the turning HST transmission mechanism 38 is driven while the straight traveling HST transmission mechanism 35 is driven, a difference occurs in the driving speed of the left and right traveling crawlers 2, and the traveling machine body 1 moves forward or backward. Turn left or right with a turning radius greater than the spin turn turning radius. The turning radius at this time is determined according to the difference in driving speed between the left and right traveling crawlers 2.

(3). Detailed structure in the control unit Next, the detailed structure in the control unit will be described with reference to FIGS. 3 and 4.

  A vertically long steering column 71 is erected in front of a control seat 70 disposed in the cabin-type control unit 5. A round steering handle 73 for changing the traveling (turning) direction and the turning speed of the traveling machine body 1 is attached to a handle shaft 72 (see FIG. 5) protruding upward from the steering column 71. In the embodiment, the rotatable range of the steering handle 73 is set to a size of about 135 ° to the left and right across the neutral position. Needless to say, when the hand is released from the steering handle 73, the steering handle 73 is automatically returned to the neutral position.

  A center panel body 74 having a liquid crystal display device 75 and the like is disposed inside a substantially annular handle wheel portion of the steering handle 73. The center panel body 74 is fixed only to the steering column 71 and is not connected to the steering handle 73. Therefore, even if the steering handle 73 is rotated, the center panel body 74 and the liquid crystal display device 75 are also operated. Does not move, and the screen is always easy to see from the operator.

  On one side of the control seat 70 (left side in the embodiment), a side panel body 76 that is long in the front-rear direction is disposed. On the side panel body 76, a main transmission lever 77, an auxiliary transmission lever 78, and a clutch lever 79 are arranged in order from the front.

  The main speed change lever 77 is used to move the traveling machine body 1 forward, stop, reverse and change its vehicle speed steplessly. The main transmission lever 77 according to the embodiment is configured to be able to tilt forward and backward along a guide groove 80 having a crank shape in plan view in the side panel body 76.

  Although details will be described later, when the main transmission lever 77 is tilted forward from a neutral (stopped) position in a substantially vertical posture, the traveling machine body 1 is configured to move forward by driving of the straight traveling HST transmission mechanism 35. . And it is comprised so that the advance speed of the traveling body 1 may become quick, so that the forward tilt angle of the main transmission lever 77 is large. On the contrary, when the main transmission lever 77 is tilted backward from the neutral position, the traveling machine body 1 is configured to move backward by driving the straight traveling HST transmission mechanism 35. And it is comprised so that the reverse speed of the traveling body 1 may become quick, so that the inclination angle to the back of the main transmission lever 77 is large.

  The sub-transmission lever 78 changes the sub-transmission mechanism 32 in the mission case 30 in accordance with the work state, thereby adjusting the output range of the hydraulic drive means 31 (the rotational direction and the rotational speed of the linear motor shaft 42). This is for setting and holding in four stages of low speed, medium speed, high speed and neutral. Similarly to the main transmission lever 77, the auxiliary transmission lever 78 is also configured to be tiltable back and forth.

  The clutch lever 79 serves as a single power transmission lever for the mowing unit 3 and a power transmission operation lever for the threshing unit 8, and is substantially L-shaped in plan view in the side panel body 76. The guide groove 81 is configured to be tiltable in the left and right and front and rear directions.

  When the clutch lever 79 of the embodiment is tilted to the left end position of the left and right groove portions 81a in the guide groove 81, both the mowing clutch and the threshing clutch (both not shown) are turned off, and the right end position (the front and rear groove portions 81b of the left and right groove portions 81b). When it is tilted to the rear end position), only the threshing clutch is engaged, and when it is tilted to the front end position of the front / rear groove 81b, both clutches are engaged.

  On the side panel body 76, various switches for operation and a plurality of dials for setting are also arranged. In the embodiment, at a position ahead of the main speed change lever 77 in the side panel body 76, an automobile speed switch 82, a load factor setting dial 83 as load factor setting means, a standby time setting device 98 as standby time setting means, An automatic cutting height switch 84, a cutting height setting dial 85, an automatic horizontal switch 86, an inclination setting dial 87, and the like are arranged.

  The vehicle speed switch 82 is for operating on / off of the vehicle speed control that decelerates the vehicle speed when the engine 6 is overloaded and keeps the rotational drive of the mowing unit 3 and the threshing unit 8 constant. The load factor setting dial 83 is used for manually setting the set load factor LFa of the engine 6 during vehicle speed control. Although details will be described later, in the embodiment, when the load factor LF of the engine 6 is equal to or higher than the set load factor LFa, the vehicle speed in the forward direction of the traveling machine body 1 is set to be forcibly decelerated.

  Here, the engine load factor LF will be described. The engine load factor LF is defined as the ratio of the engine load during the cutting and threshing operation, with the engine load detected by the rack position sensor 200 described later as 100%. It is calculated. The engine load factor LF in the idling state becomes 0 (zero).

  The set load factor LFa is a threshold value corresponding to when the engine 6 is overloaded. In other words, the set load factor LFa is a reference value for determining whether or not the engine 6 is in an overload state. In this case, the load factor setting dial 83 changes and adjusts the position of the knob (pointer) continuously (analog) or stepwise (digitally), and sets the load factor LFa within a range of 70 to 100%. It is configured to be arbitrarily adjustable.

  Although details will be described later, in the embodiment, when the set load factor LFa is determined, the corresponding return load factor LFb is automatically set. The return load factor LFb is a value (LFb (%) = LFa−α) smaller than the set load factor LFa by a predetermined rate. When the engine load factor LF becomes equal to or lower than the return load factor LFb after the forced deceleration in the vehicle speed control, the vehicle speed in the forward direction of the traveling machine body 1 is increased to the original vehicle speed corresponding to the forward tilting operation position of the main transmission lever 77. It is set to be.

  The standby time setter 98 is a standby time Tw from the end of the previous deceleration operation to the start of the next deceleration operation or return acceleration operation in the vehicle speed control (hereinafter referred to as a set standby time Tw; see FIGS. 11 and 12). As with the load factor setting dial 83 described above, the setting device 98 also changes the position of the knob (pointer) continuously (analog) or stepwise (digital). -It is configured to be adjustable.

  The automatic cutting height switch 84 is for operating on / off of automatic cutting height control for maintaining the cutting unit 3 at a predetermined cutting height position. The cutting height setting dial 85 is used to set and operate the cutting height position during automatic cutting height control. The automatic horizontal switch 86 is for operating on / off of automatic horizontal control for maintaining the traveling machine body 1 in a horizontal horizontal posture. The tilt setting dial 87 is for setting and operating the left and right tilt angle of the traveling machine body 1.

  Further, a constant rotation control switch 88, an accelerator dial 89, a reel height adjustment dial 90, a reel speed change automatic switch 91, and the like are disposed at a position behind the main speed change lever 77 in the side panel body 76.

  The constant rotation control switch 88 is for operating on / off of constant rotation control for keeping the rotation speed of the engine 6 constant. The accelerator dial 89 is for adjusting the rotational speed of the engine 6. The reel height adjustment dial 90 is for adjusting the height position of the scraping reel 18 of the cutting unit 3. The reel speed change automatic switch 91 is for operating a mode for automatically adjusting the rotational speed of the scraping reel 18 in accordance with the vehicle speed of the traveling machine body 1.

  On the lower surface side of the control seat 70, a seat switch 92 for detecting whether an operator is sitting on the control seat 70 is disposed. On the lower surface side of the step plate 93 located between the control seat 70 and the steering handle 73, a pair of left and right step switches 94 for detecting whether or not the operator's feet are placed on the step plate 93 are provided. Has been placed.

  The seat switch 92 and both step switches 94 correspond to presence detecting means for detecting whether or not there is an operator in the control unit 5. When at least one of the seat switch 92 and the both step switches 94 is turned on and operated, the engine 6 is allowed to start and the power transmission from the engine 6 to the traveling unit and the working unit is permitted. Yes. Further, when all of the seat switch 92 and both step switches 94 are turned off, the driving of the engine 6 is stopped, or the power transmission from the engine 6 to the traveling unit and the working unit is automatically cut off. Is set to Note that at least one of the switches 92 and 94 may be provided.

(4). Connection structure between main transmission lever and steering handle and hydraulic drive means Next, a connection structure between the main transmission lever and steering handle and the hydraulic drive means will be described with reference to FIGS.

  A main speed change lever 77 as a speed change operation means is linked to a mechanical switching means 100 disposed in the steering column 71 via a relay link mechanism 95. Further, the handle shaft 72 of the steering handle 73 is also linked to the mechanical switching means 100.

The mechanical switching means 100 of the embodiment includes:
1. When the steering handle 73 is rotated to a position other than the neutral position while the main speed change lever 77 is tilted to a position other than the neutral position, the traveling machine body 1 moves to the left with a smaller turning radius as the rotation operation amount increases. Alternatively, the vehicle speed of the traveling machine body 1 (turning speed when moving forward and backward) decreases as the turning radius decreases and the turning radius decreases.
2. Even when the main transmission lever 77 is tilted in either the forward or backward direction, the turning operation direction of the steering handle 73 coincides with the turning direction of the traveling machine body 1 (the steering handle 73 is turned to the right). If it is turned, the traveling machine body 1 turns to the right, and if the steering handle 73 is turned to the left, the traveling machine body 1 turns to the left)
3. If the main transmission lever 77 is in the neutral position, it does not function even if the steering handle 73 is operated.
In order to execute various operations, the operating force from the main transmission lever 77 and the steering handle 73 is appropriately converted and transmitted to the vertically long double shaft 101 that is rotatably arranged at the lower end of the steering column 71. Is configured to do.

  The mechanical switching means 100 itself is not directly related to the present invention and will not be described in detail. However, if necessary, refer to Japanese Patent Application Laid-Open No. 2002-274421.

  The double shaft 101 associated with the mechanical switching means 100 is formed in a vertically long concentric shape by a straight-moving outer cylinder shaft 102 and a turning inner shaft 103 that can be rotated independently of each other. The rectilinear outer cylinder shaft 102 is linked to a rectilinear rotation shaft 105 protruding forward from the front surface of the mission case 30 via a rectilinear link mechanism 104. On the other hand, the turning inner shaft 103 is coupled to a turning rotation shaft 107 protruding forward from the front surface of the mission case 30 via a turning link mechanism 106.

  Here, the rectilinear rotation shaft 105 is for adjusting the inclination angle of the rotary swash plate of the first hydraulic pump 36 in the rectilinear HST transmission mechanism 35, and the shift output of the rectilinear HST transmission mechanism 35. Functions as an adjustment unit that adjusts The turning shaft 107 for turning is used to adjust the inclination angle of the rotary swash plate of the second hydraulic pump 39 in the turning HST transmission mechanism 38, and adjusts the shift output of the turning HST transmission mechanism 38. Functions as a control unit.

  The straight-travel link mechanism 104 is a straight-travel link projectingly provided on a lateral support shaft 110 and a straight-travel outer cylinder shaft 102 that are rotatably inserted into a support tube 109 fixed to the upper surface of the mission case 30 via a bracket 108. A straight relay rod 113 that connects the rotary arm 111 and the first straight swing arm 112 fixed to one end (right end in the embodiment) of the horizontal support shaft 110 and the other end of the horizontal support shaft 110 (the embodiment). In this case, a linearly-moving interlocking rod 116 that connects a linearly-moving second swinging arm 114 fixed to the left end) and a linearly-moving operating arm 115 attached to the linearly-rotating shaft 105 is provided.

  One end portion (front end portion in the embodiment) of the rectilinear relay rod 113 is pivotally attached to a rectilinear pivot arm 111 on the rectilinear outer cylinder shaft 102 side so as to be pivotable by a longitudinal pivot pin 117. Yes. The other end portion (rear end portion in the embodiment) of the rectilinear relay rod 113 is pivoted to the first rectilinear swing arm 112 on the side support shaft 110 side via a pivot pin 118 that is laterally directed laterally. It is worn.

  One end portion (upper end portion in the embodiment) of the straight interlocking rod 116 is pivotally attached to the second straight swing arm 114 on the side of the lateral support shaft 110 so as to be rotatable by left and right laterally attached pivot pins 119. Yes. The other end portion (lower end portion in the embodiment) of the rectilinear interlocking rod 116 is pivotally attached to a rectilinear operation arm 115 on the rectilinear rotation shaft 105 side via a pivoting pin 120 that is oriented in the front-rear and lateral directions. ing.

  When the main transmission lever 77 is tilted forward from the neutral position, the mechanical switching means 100 moves the outer cylinder shaft 102 for rectilinear movement and the pivot arm 111 for rectilinear movement around the inner shaft 103 for rotation through the relay link mechanism 95. By integrally rotating in the direction of the arrow SA, the straight traveling relay rod 113 is pulled forward (moved), and the first straight swing arm 112, the lateral support shaft 110, and the second straight swing. The arm 114 rotates integrally in the direction of the arrow SB around the lateral support shaft 110.

  Then, when the second swing arm 114 for rectilinear movement lifts the interlocking rod 116 for rectilinear movement by the rotational movement in the direction of the arrow SB, the operation arm 115 for rectilinear movement, and hence the rotation shaft 105 for rectilinear advance, moves in the direction of the arrow SC (forward increase). It rotates in the speed direction (or backward deceleration direction, see FIGS. 5 and 6). As a result, the traveling machine body 1 performs the forward movement in proportion to the forward tilting operation amount of the main transmission lever 77.

  On the other hand, when the main transmission lever 77 is tilted backward from the neutral position, the mechanical switching means 100 moves the straight cylinder shaft 102 and the straight rotation arm 111 in the direction of the arrow SD via the relay link mechanism 95. By rotating integrally, the rectilinear relay rod 113 moves rearward, and the first rectilinear swing arm 112, the lateral support shaft 110, and the second rectilinear swing arm 114 are opposite to the previous arrows. Rotates integrally in the SE direction.

  Then, when the second rectilinear swing arm 114 pushes down the rectilinear interlocking rod 116 by the rotational movement in the arrow SE direction, the rectilinear operation arm 115 and hence the rectilinear pivot shaft 105 are moved in the arrow SF direction (reverse increase). It rotates in the speed direction (or forward deceleration direction, see FIGS. 5 and 6). As a result, the traveling machine body 1 performs the reverse operation in proportion to the backward tilting operation amount of the main transmission lever 77.

  On the other hand, the turning link mechanism 106 includes a turning cylinder 121 that is rotatably fitted to a projecting portion of the lateral support shaft 110 from the support cylinder 109, and a turning turning arm that protrudes from the turning inner shaft 103. 122 and a pivot rod 124 for pivoting that connects the first pivot arm 123 for pivoting provided on the rotating cylinder 121 and a substantially L-shaped first rotating arm for protruding that is provided on the rotating cylinder 121. 2 is provided with a turning interlocking rod 127 that connects a swing arm 125 and a turning operation arm 126 attached to the turning shaft 107 for turning.

  One end portion (front end portion in the embodiment) of the turning relay rod 124 is pivotally attached to the turning rotation arm 122 on the turning inner shaft 103 side so as to be turnable by a longitudinally attached pivot pin 128. . The other end portion (rear end portion in the embodiment) of the turning relay rod 124 pivots to the turning first swing arm 123 on the turning cylinder 121 side via a pivot pin 129 that is laterally laterally oriented. It is worn.

  One end portion (upper end portion in the embodiment) of the turning interlocking rod 127 is pivotally attached to the second swinging arm 125 for turning on the side of the turning cylinder 121 so as to be turnable by a pivoting pin 130 facing left and right laterally. Yes. The other end portion (the lower end portion in the embodiment) of the turning interlocking rod 127 is pivotally attached to the turning operation arm 126 on the turning turning shaft 107 side via a pivoting pin 131 that is oriented in the front-rear and lateral directions. ing.

  For example, when the steering handle 73 is turned leftward with the main transmission lever 77 tilted forward, the mechanical switching means 100 is connected to the turning inner shaft 103 and the turning turning arm via the handle shaft 72. By rotating 122 in the direction of the arrow TA, the turning relay rod 124 is pulled forward, and the first turning arm 123 for turning, the turning cylinder 121 and the second turning arm 125 for turning are moved. It rotates integrally in the direction of arrow TB around the horizontal support shaft 110.

  Then, the second swing arm 125 for turning pulls up the turning interlocking rod 127 by turning movement in the direction of arrow TB, so that the turning operation arm 126 and consequently the turning shaft 107 for turning turn in the direction of arrow TC (forward leftward rotation). Rotate in the turning direction (see FIGS. 5 and 6). As a result, the traveling machine body 1 performs a left turn operation in proportion to the amount of leftward turning operation of the steering handle 73.

  In this case, the linear movement link mechanism 104 causes the linear movement rotation shaft 105 to move in the direction of the arrow SF (forward deceleration direction) in proportion to the amount of rotation of the steering handle 73 in the left direction by the action of the mechanical switching means 100. ), And the forward turning speed of the traveling machine body 1 is decelerated corresponding to the turning radius at that time.

  On the other hand, when the steering handle 73 is rotated to the right with the main transmission lever 77 tilted forward, the mechanical switching means 100 is connected to the turning inner shaft 103 and the turning rotation via the handle shaft 72. By rotating the moving arm 122 integrally in the direction of the arrow TD, the turning relay rod 124 moves rearward, and the first turning arm 123 for turning, the turning cylinder 121, and the second turning arm for turning. 125 rotates integrally in the direction of the arrow TE opposite to the previous one.

  Then, the turning swing arm 125 pushes down the turning interlocking rod 127 by the turning movement in the direction of the arrow TE, so that the turning operation arm 126 and the turning turning shaft 107 are moved in the direction of the arrow TF (forward right). It turns in the turning direction (see FIGS. 5 and 6). As a result, the traveling machine body 1 performs a right turn operation in proportion to the amount of turning operation of the steering handle 73 in the right direction.

  Also in this case, the linear link mechanism 104 causes the linear rotation shaft 105 to move in the direction of the arrow SF (forward deceleration) in proportion to the amount of rotation of the steering handle 73 in the right direction by the action of the mechanical switching means 100. The forward turning speed of the traveling machine body 1 is decelerated corresponding to the turning radius at that time.

  When the steering handle 73 is turned left and right with the main transmission lever 77 tilted rearward, the operations of the turning link mechanism 106 and the straight traveling link mechanism 104 are opposite to those described above. That is, the operation of both link mechanisms 106 and 104 during forward left turn is the same as that during reverse right turn, while the operation of both link mechanisms 106 and 104 during forward right turn is the same as that during reverse left turn. Is set to

  As shown in FIGS. 6 and 7, the rectilinear rotation shaft 105 has a rectilinear detent for holding the rotary swash plate of the first hydraulic pump 36 in the neutral position when the main transmission lever 77 is in the neutral position. Means 132 are attached. Similarly, a turning detent means 133 for holding the rotating swash plate of the second hydraulic pump 39 in the neutral position when the steering handle 73 is in the neutral position is attached to the turning shaft 107 for turning. Yes.

  As is clear from FIG. 6, the straight detent means 132 and the turning detent means 133 are arranged symmetrically and basically have the same configuration. In the straight detent means 132, a substantially cylindrical boss member 134 is fitted on the straight rotation shaft 105 as an adjustment portion of the straight HST transmission mechanism 35 so as to rotate integrally ( (See FIG. 7). A midway portion of the straight advance detent rod 135 formed in a substantially Y-plate shape is fixed to the front end portion of the straight advance rotation shaft 105 with a nut 136.

  A corner portion of a neutral holding arm 138 formed in a substantially L-shape is pivotally supported by a pivot shaft 137 projecting from a position near the left and right center of the mission case 30. A neutral holding roller 139 that is in contact with a neutral holding cam surface 135a formed on the upper end surface of the straight advance detent rod 135 is rotatably attached to the tip of the lateral arm portion 138a of the neutral holding arm 138. The neutral holding roller 139 is configured to always press and contact the neutral holding cam surface 135a of the straight advance detent rod 135 by the elastic biasing force of the biasing spring 140. The urging spring 140 according to the embodiment is mounted between the vertical arm portion 138b of the neutral holding arm 138 for straight movement and the vertical arm portion 158b (details will be described later) of the neutral holding arm 158 for turning. Has been.

  On the other hand, a corner portion of a substantially L-shaped straight advance operation arm 115 and a stopper plate 142 are fixed to a cylindrical member 141 that is rotatably fitted in the middle portion of the boss member 134. In the rectilinear operation arm 115, the distal end of the lateral arm portion 115a is pivotally attached to the other end portion (lower end portion in the embodiment) of the rectilinear interlocking rod 116 by a pivoting pin 120 that is front-rear and laterally oriented. . The vertical arm 115b of the straight operation arm 115 extends so as to overlap the vertical hook 135b of the straight detent rod 135 in a front view.

  A torsion spring 143 as return biasing means is fitted on the outer peripheral portion of the cylindrical member 141. Both end portions of the torsion spring 143 extend downward while intersecting, and sandwich the vertical arm portion 115b of the straight advance operation arm 115 and the vertical flange portion 135b of the straight advance detent rod 135.

  It should be noted that a pair of stopper receivers for restricting the rotation of the rectilinear detent rod 135 and the rectilinear operation arm 115 about the rectilinear rotation shaft 105 are provided on the left and right sides of the vertical rod portion 135b of the rectilinear detent rod 135. 144 is arranged. These stopper receivers 144 are fixed to the lower part of the front surface of the stopper plate 142. When the contact body 145 projecting rearward from the vertical flange 135b hits each stopper receiving body 144, the straight detent bar 135 and the straight operation arm 115 do not rotate more than a predetermined angle around the straight rotation shaft 105. So that it is regulated.

  A potentiometer-type main shift position sensor 147 having a sensing arm 148 that can be turned up and down is attached to the bracket 146 disposed on the front side of the mission case 30. The main shift position sensor 147 is configured to detect the inclination angle of the rotary swash plate in the first hydraulic pump 36 based on the rotation angle of the sensing arm 148 caused by contact with the operation pin 149 provided at the upper end of the straight detent rod 135. The amount of tilting operation of the main speed change lever 77 is detected.

  In the turning detent means 133, a substantially cylindrical boss member (not shown) is fitted on the turning rotation shaft 107 as the adjusting portion of the turning HST transmission mechanism 38 so as to rotate integrally. Has been. A midway portion of the turning detent rod 155 formed in a substantially Y-plate shape is fixed to the distal end portion of the turning shaft 107 for turning by a nut 156.

  A corner portion of a neutral holding arm 158 formed in a substantially L-shape is pivotally supported by a pivot shaft 157 projecting from a position near the left and right center in the mission case 30. A neutral holding roller 159 that is in contact with a neutral holding cam surface 155a formed on the upper end surface of the turning detent rod 155 is rotatably attached to the tip of the lateral arm portion 158a of the neutral holding arm 158. The neutral holding roller 159 is configured to always press and contact the neutral holding cam surface 155a of the turning detent rod 155 by the elastic biasing force of the biasing spring 140.

  On the other hand, a corner portion of a substantially L-shaped turning operation arm 126 and a stopper plate 162 are fixed to a cylindrical member (not shown) that is rotatably fitted in the middle portion of the boss member. . In the turning operation arm 126, the distal end of the horizontal arm portion 126a is pivotally attached to the other end portion (the lower end portion in the embodiment) of the turning interlocking rod 127 with a pivoting pin 131 that is oriented in the front-rear and lateral directions. . The vertical arm portion 126b of the turning operation arm 126 extends so as to overlap the vertical hook portion 155b of the turning detent rod 155 in a front view.

  A torsion spring 163 as return biasing means is fitted on the outer peripheral portion of a cylindrical member (not shown). Both end portions of the torsion spring 163 extend downward while intersecting, and sandwich the vertical arm portion 126b of the turning operation arm 126 and the vertical hook portion 155b of the turning detent rod 155.

  Note that a pair of stopper receivers for restricting the turning of the turning detent rod 155 and the turning operation arm 126 about the turning rotary shaft 107 are provided on the left and right sides of the vertical rod portion 155b of the turning detent rod 155. 164 is arranged. These stopper receivers 164 are fixed to the lower part of the front surface of the stopper plate 162. When the contact body 165 projecting rearward from the vertical flange portion 155b hits each stopper receiving body 164, the turning detent rod 155 and the turning operation arm 126 do not turn around the turning shaft 107 for turning more than a predetermined angle. So that it is regulated.

(5). Next, the interlocking structure between the electric motor and the hydraulic drive means will be described with reference to FIGS.

  An electric motor 170 as a speed change actuator is connected to an operation system (relay link mechanism 95) from the main speed change lever 77 toward the straight movement turning shaft 105 on the straight movement turning shaft 105 which is an adjustment portion of the straight advance HST transmission mechanism 35. The mechanical switching means 100 and the straight traveling link mechanism 104) are associated with each other via a link system 171 of a different system.

  In the embodiment, an electric motor 170 capable of forward and reverse rotation as a speed change actuator is screwed to the back side of the bracket plate 169 fixed to the support cylinder 109 on the mission case 30. A pinion gear 173 as a drive side gear is fixed to the motor output shaft 172 of the electric motor 170. On the other hand, at a position below the electric motor 170 on the back surface of the bracket plate 169, a sector gear 174 as a driven gear is rotated by a pivot 175 extending in parallel with the rectilinear pivot 105 and the pivot pivot 107. It is pivotally attached. By engaging both the gears 173 and 174, the rotational driving force from the electric motor 170 can be transmitted to the rectilinear rotation shaft 105 via the linkage mechanism 171.

  The linkage mechanism 171 links the vertical rod 135b of the straight detent rod 135 as an adjustment member, the above-described sector gear 174 and the relay arm 176 fixed to the pivot 175, the vertical rod 135b and the relay arm 176. And a connecting rod 177 for rotating.

  In the embodiment, the vertical hook 135b of the straight detent bar 135 extends longer than the vertical bar 155b of the turning detent bar 155. A lower end portion of the vertical rod portion 135b of the straight detent rod 135 is pivotally attached to one end portion of the linkage rod 177 with a pivoting pin 178 oriented in the front-rear and lateral directions.

  A guide slot 179 extending in the longitudinal direction is formed at the other end of the linkage rod 177 on the relay arm 176 side. The other end of the linkage rod 177 and the relay arm 176 are connected via a pivot pin 180 inserted in the guide slot 179.

  The relay arm 176 and the sector gear 174 are driven from the initial position shown in FIGS. 6, 8 </ b> A, and 8 </ b> C (the standby position when the vehicle speed control is not executed) by the rotational drive of the pinion gear 173 by the electric motor 170. In the range up to a maximum forced deceleration position shown in FIG.

  A pair of stopper shafts 181 for restricting the rotation of the sector gear 174 around the pivot 175 is disposed on the left and right sides of the sector gear 174 in the bracket plate 169. The sector gear 174 is regulated so that the sector gear 174 and the relay arm 176 do not rotate beyond the range of the initial position to the maximum forced deceleration position around the pivot 175 by the side edge of the rotation direction in the sector gear 174 hitting each stopper shaft 181. ing.

  With the configuration described above, unlike the conventional method (the configuration of Patent Document 1), it is not necessary to interlock the operation system from the main transmission lever 77 toward the rectilinear rotation shaft 105 and the electric motor 170. . For this reason, restrictions such as the layout of the electric motor 170 and the linkage mechanism 171 are remarkably reduced, and the degree of freedom in designing an interlocking structure for vehicle speed control is improved. As a result, the interlocking structure can be simplified and the number of parts can be reduced, which can contribute to the reduction of manufacturing costs.

  When the straight detent rod 135 is in the neutral position and the sector gear 174 and the relay arm 176 are in the initial position (see FIG. 6), that is, when the main transmission lever 77 is in the neutral position and the traveling machine body 1 is stopped. Is set such that the pivot pin 180 fixed to the relay arm 176 is positioned at the longitudinal center of the guide slot 179 in the linkage rod 177.

  When the vehicle speed switch 82 is in the off state (vehicle speed control is not executed), the sector gear 174 and the relay arm 176 are always held at the initial positions. In this state, even if the main transmission lever 77 is tilted in either the front or rear direction, the guide pins 180 so that the pivot pins 180 on the relay arm 176 side do not hit both edges in the longitudinal direction of the guide slot 179. The major axis dimension of the slot 179 is set. That is, when the main speed change lever 77 is tilted when the vehicle speed control is not executed, the pivot pin 180 on the relay arm 176 side slides in the guide groove hole 179 of the linkage rod 177, but the guide groove The hole 179 becomes idle without being caught on both edges in the longitudinal direction, and the presence of the linkage mechanism 171 does not hinder the tilting operation of the main transmission lever 77.

  When the main transmission lever 77 is tilted forward from the neutral position, the linear operation arm 115 rotates in the arrow SC direction (forward acceleration direction) via the linear link mechanism 104. Since the vertical arm 115b of the straight operation arm 115 is sandwiched together with the vertical hook 135b of the straight detent rod 135 at both ends of the torsion spring 143, it is fixed to the straight detent rod 135 and this. The rectilinear rotation shaft 105 also rotates in the arrow SC direction (forward acceleration direction) (see FIG. 8A). As a result, the vehicle speed in the forward direction of the traveling machine body 1 is increased.

  When the straight detent rod 135 rotates in the direction of the arrow SC (forward speed increasing direction) around the straight rotation shaft 105, the linkage rod 177 is pushed obliquely upward toward the pivot pin 180 on the relay arm 176 side, The pivot pin 180 slides relative to the vicinity of the lower edge of the guide slot 179 in the linkage rod 177 (the edge near the vertical flange 135b) (see FIG. 8A).

  When the vehicle speed switch 82 is in the on state (vehicle speed control is executed), the relay arm 176 and the sector gear 174 are moved from the initial position to the maximum forced deceleration position by the rotational drive of the pinion gear 173 by the electric motor 170. When pivoted in the direction of the arrow RE (see FIG. 8B), the pivot pin 180 on the relay arm 176 side hits the lower edge of the guide slot 179 in the linkage rod 177, causing the linkage rod 177 to move straight detent rod 135. The straight detent rod 135 and, consequently, the straight rotation shaft 105 are rotated in the direction of the arrow SF (forward deceleration direction). As a result, the vehicle speed in the forward direction of the traveling machine body 1 is reduced.

  In the embodiment, when the relay arm 176 and the sector gear 174 are rotated to the maximum forced deceleration position, the rectilinear detent rod 135 is rotated back to the neutral position (see FIG. 8B), and the rectilinear pivot shaft 105 is moved. As a result, the rotary swash plate of the first hydraulic pump 36 is moved to the neutral position. For this reason, when the engine 6 is overloaded during the execution of the vehicle speed control, the traveling machine body 1 can be decelerated to a state where it substantially stops.

  According to such a configuration, when the engine 6 is overloaded, the straight drive HST transmission mechanism 35 and the power from the engine 6 are not used for the forward movement of the traveling machine body 1, and the reaping unit 3 and the threshing unit 8 are driven to rotate. Therefore, even with an ordinary combine with a heavy load fluctuation, clogging of the cutting part 3, reduction in rotation of the threshing part 8, and engine stop can be reliably suppressed, and the effectiveness of vehicle speed control (stable Improved).

  Further, the vertical flange 135b of the straight advance detent rod 135 and the vertical arm 115b of the linear operation arm 115 are sandwiched together at both ends of the torsion spring 143, but the elastic restoring force of the torsion spring 143 is Compared with the force for moving the straight link mechanism 104 including the straight operation arm 115, the force is much smaller.

  For this reason, when the vehicle speed in the forward direction of the traveling machine body 1 is decelerated during execution of the vehicle speed control, the straight detent rod 135 (and hence the straight rotation shaft 105) rotates in the direction of the arrow SF (forward deceleration direction). However, the straight advance operation arm 115 is held at a position corresponding to the forward tilting operation position of the main transmission lever 77 (see FIG. 8B).

  Therefore, the rotational force of the straight travel detent rod 135 in the direction of the arrow SF (forward / deceleration direction) does not propagate to the main speed change lever 77 via the straight travel link mechanism 104 and the mechanical switching means 100, and the vehicle speed control is executed. Whenever the traveling machine body 1 is forcibly decelerated, there is no inconvenience that the main transmission lever 77 moves freely in front of the eyes.

  When the vehicle speed control is performed, the vehicle speed in the forward direction of the traveling machine body 1 is decelerated, and then the relay arm 176 and the sector gear 174 are rotated in the direction of the arrow BA by the rotational drive of the pinion gear 173 by the electric motor 170 to the initial position. (See FIG. 8 (c)), the pivot pin 180 on the relay arm 176 side slides in the guide slot 179 of the linkage rod 177, and from the lower edge of the guide slot 179. Leave.

  As a result, there is room for the elastic restoring force of the torsion spring 143 to act as much as the pivot pin 180 moves away from the lower edge of the guide slot 179. With this elastic restoring force, the vertical arm in the straight operation arm 115 is provided. The straight-ahead detent rod 135 and, therefore, the rectilinear rotation shaft 105 returns and rotates at a moderate speed to the position of the portion 115 to return to the state shown in FIG.

  At this time, the return rotation position of the straight detent rod 135 is the original position corresponding to the forward tilting operation position of the main transmission lever 77 (the position before the relay arm 176 and the sector gear 174 are rotated in the direction of the arrow RE). is there. As a result, the vehicle speed in the forward direction of the traveling machine body 1 gradually increases to the original vehicle speed corresponding to the forward tilting operation position of the main transmission lever 77.

  In this case, the linkage rod 177 is pushed obliquely upward toward the pivot pin 180 on the relay arm 176 side by the return rotation of the straight detent rod 135 in the arrow SC direction, and the pivot pin 180 is moved to the linkage rod 177. Needless to say, the guide slot 179 slides relatively near the lower edge of the guide slot 179 (see FIG. 8A).

  According to this configuration, the operator does not need to repeat the forward tilting operation of the main transmission lever 77 in order to restore the vehicle speed after the vehicle speed in the forward direction of the traveling machine body 1 is forcibly decelerated by the vehicle speed control. For this reason, the operation frequency of the main transmission lever 77 can be reduced, and the operation burden on the operator can be reduced.

  Further, by using the elastic restoring force of the torsion spring 143, the linear advancement detent rod 135 and the rectilinear advancement rotary shaft 105 are returned and rotated at a moderate speed to the position of the vertical arm portion 115 in the rectilinear operation arm 115 to run. Since the vehicle speed in the forward direction of the vehicle body 1 is gradually increased to the original vehicle speed corresponding to the forward tilting operation position of the main speed change lever 77, the traveling vehicle body 1 is safe without being rapidly increased.

  In addition, since the return vehicle speed does not exceed the speed corresponding to the forward tilting operation position of the main transmission lever 77, it is possible to reliably avoid the possibility that the vehicle speed will increase abnormally, and to ensure sufficient safety.

  In the embodiment, even when the vehicle speed control is being executed, the main transmission lever 77 is tilted backward to move the straight detent rod 135 and the straight rotation shaft 105 in the direction of the arrow SF (reverse acceleration direction). ) (When the traveling machine body 1 is retracted), the electric motor 170 is configured not to be driven.

  As shown in FIGS. 6 and 7, a potentiometer type forced deceleration position sensor 182 having a sensing arm 183 that can be turned up and down is attached to the bracket plate 169 fixed to the support cylinder 109 on the mission case 30. It has been. This forced deceleration position sensor 182 is based on the pivoting angle of the sensing arm 183 caused by the contact with the operating pin 185 of the pivoting plate 184 fixed to the pivot 175 separately from the relay arm 176. The position is detected.

(6). Configuration of Control Unit Next, a configuration for executing vehicle speed control and the like of the traveling aircraft will be described with reference to FIGS. 9 and 10.

  Although not shown in detail, a controller 190 such as a microcomputer as vehicle speed control means mounted on the traveling machine body 1 is a central processing unit 191 (CPU) for executing various arithmetic processes and controls, a control program and data. Read-only memory 192 (ROM) for storing data, read / write memory 193 (RAM) as needed to temporarily store control programs and data, clocks as timer functions, input / output devices (sensors, actuators, etc.) ) And an input / output interface (not shown) for exchanging data.

  In the ROM 192 of the controller 190, a detection value V (vehicle speed of the traveling vehicle body 1) of a vehicle speed sensor 197 provided in association with the brake shaft 48 (see FIG. 2) and vehicle speed control execution for the vehicle speed V are executed. A relational expression or a control map showing a relationship with the deceleration amount vr at the time is stored in advance.

  An example of the relational expression in this case is vr = A × V. Here, A is a proportionality constant. A case where such a relational expression is used as a control map is shown in FIG. In FIG. 10, the vehicle speed V of the traveling machine body 1 is taken on the horizontal axis, and the deceleration amount vr is taken on the vertical axis.

  As shown in FIG. 10, the proportionality constant A is a value greater than 0 and 1 or less (0 <A ≦ 1), and the relationship between the vehicle speed V and the deceleration amount vr is represented by a straight line having a positive slope. Yes. In other words, the vehicle speed V and the deceleration amount vr have a relationship that the deceleration amount vr increases (decelerates greatly) as the vehicle speed V increases (increases). Since 0 <A ≦ 1, the deceleration amount vr does not exceed the vehicle speed V. In other words, the traveling machine body 1 does not decelerate excessively when the vehicle speed control is executed. Note that data of a pair of the vehicle speed V and the corresponding deceleration amount vr may be stored in the ROM 192 of the controller 190 as a table map.

  The input interface of the controller 190 includes, for example, an automobile speed switch 82, a load factor setting dial 83, an automatic cutting height switch 84, a cutting height setting dial 85, an automatic horizontal switch 86, an inclination setting dial 87, a constant rotation control switch 88, Accelerator dial 89, reel height adjustment dial 90, reel shift automatic switch 91, main shift position sensor 147, auxiliary transmission lever 78, cutting clutch sensor for detecting the on / off state of the power transmission cutting clutch with respect to the cutting unit 3 194, threshing clutch sensor 195 for detecting the on / off state of the power threshing clutch for the threshing unit 8, a forced deceleration position sensor 182, a seat switch 92, left and right step switches 94, and the rotational speed of the engine 6 are detected. Engine rotation sensor 196, vehicle speed sensor 197, a rack position sensor 200 as a load detection means for detecting the fuel supply amount from the rack position of the fuel injection pump 199 with an electronic governor 198 as a fuel supply means, a power switch 201 for turning on and off the entire combine power, A standby time setting unit 98 as a standby time setting means is connected.

  On the other hand, the output interface of the controller 140 includes, for example, an electronic governor 198 that adjusts and controls the load (output) of the engine 6, and a rack actuator that adjusts the rack position of the fuel injection pump 199 so that the rotational speed of the engine 6 becomes a predetermined value. 202, an electric motor 170 as a speed change actuator, a liquid crystal display device 75, and the like are connected.

(7). Next, an example of vehicle speed control will be described with reference to the flowchart of FIG. 11 and the time chart of FIG.

  When the engine load factor LF obtained from the detection information of the rack position sensor 200 is equal to or higher than the set load factor LFa, the controller 190 serving as the vehicle speed control means is connected to the rectilinear turning shaft 105 of the rectilinear HST transmission mechanism 35. When the electric motor 170 is driven to rotate in the direction of arrow SF (forward / deceleration direction) via 171 and then the engine load factor LF becomes equal to or less than the return load factor LFb, the rectilinear rotation shaft 105 causes the linkage mechanism 171 to move. Through which the electric motor 170 is driven to return to the original state in the direction of the arrow SC (forward speed increasing direction), and as a result, the rotational speed of the mowing unit 3 and the threshing unit 8 is kept constant. Execute control.

  Here, it is assumed that the vehicle speed switch 82 is set to the on state. Further, it is assumed that the set load factor LFa is preset by the load factor setting dial 83 and stored in the RAM 193 of the controller 190 together with the return load factor LFb. Also, it is assumed that the set standby time Tw is set in advance by the standby time setter 98 and stored in the RAM 193 of the controller 190.

  Further, it is assumed that data relating to a deceleration time Tr described later is stored in the ROM 192 of the controller 190, for example. The deceleration time Tr is a time required for the forced deceleration operation in the vehicle speed control (see FIG. 12). If the deceleration time Tr is too short, the operator may pick forward from the control seat 70 due to inertial force during forced deceleration. Conversely, if the deceleration time Tr is too long, the deceleration is too slow and hinders smooth execution of the cutting and threshing operation. There is a risk of causing. Therefore, the deceleration time Tr of the embodiment is set to a predetermined value (a constant value) that does not easily cause any of the above problems. In this case, the deceleration time Tr is sufficiently longer than the set standby time Tw.

  First, following the start of the vehicle speed control, it is determined whether or not the cutting clutch is engaged based on the detection information of the cutting clutch sensor 194 (step S1). When it is determined that the mowing clutch is in the disengaged state (S1: NO), it means that the combine is not performing the mowing and threshing operation, and the process returns as it is.

  When it is determined that the mowing clutch is in the engaged state (S1: YES), it means that power is transmitted to at least the mowing unit 3, and the mowing and threshing operation is being executed or is in a ready state. Accordingly, it is next determined whether or not at least one of the sheet switch 92 and the left and right step switches 94 is in the on state (step S2). When it is determined that the seat switch 92 and both the left and right step switches 94 are all turned off (S2: NO), it means that there is no operator in the control unit 5, and thus the traveling machine body 1 is automatically in this state. In order to avoid executing the vehicle speed control for increasing or decreasing speed, the process returns as it is.

  When it is determined that at least one of the seat switch 92 and the left and right step switches 94 is in the on state (S2: YES), it means that there is an operator in the control unit 5, and then the main shift position sensor 147 Based on the detected information, it is determined whether or not the main transmission lever 77 is tilted forward (step S3). When it is determined that the main transmission lever 77 is not tilted forward (i.e., neutral or backward) (S3: NO), the traveling machine body 1 is stopped or moved backward, and this state It is unlikely that you will be mowing and threshing, so you will return.

  When it is determined that the main transmission lever 77 is tilted forward (S3: YES), the traveling machine body 1 is moving forward, and there is no hindrance to the execution of the vehicle speed control. A set load factor LFa that is a set value of the load factor setting dial 83, a return load factor LFb, a detected value of the vehicle speed sensor 197 (vehicle speed V of the traveling machine body 1), and a detected value of the rack position sensor 200 (engine load) Is read (step S4), and the current engine load factor LF is calculated based on the engine load (step S5).

  Next, it is determined whether or not the current engine load factor LF is equal to or greater than the set load factor LFa read in step S4 (step S6). When it is determined that the current engine load factor LF is smaller than the set load factor LFa (S6: NO), the load applied to the mowing unit 3, the threshing unit 8, and the engine 6 is small, and there is no problem in the mowing and threshing operation. Because there is, return as it is.

  When it is determined that the current engine load factor LF is equal to or greater than the set load factor LFa (S6: YES, refer to time T1 in FIG. 12 (the engine load factor at this time is LF1)), for example, a large number of harvested cereals For example, the cutting part 3 and the threshing part 8 and thus the engine 6 are heavily loaded. If the mowing and threshing operation is continued in such a state, the engine 6 may stop due to overload (engine stop).

  Therefore, in this case, the vehicle speed V at the time of executing the vehicle speed control is calculated from the vehicle speed V (indicated as V1 in FIG. 12) at the time of reading in step S4 and the relational expression or control map stored in advance in the ROM 192 of the controller 190. A deceleration amount vr (= A × V) is calculated (step S7). Then, by driving the electric motor 170, the linear rotation shaft 105 of the linear HST transmission mechanism 35 is rotated in the direction of the arrow SF (forward deceleration direction) via the linkage mechanism 171, thereby causing a predetermined deceleration time. Tr (Tr = T2−T1 in FIG. 12) is required, and the vehicle speed V in the forward direction of the traveling machine body 1 is decelerated by the deceleration amount vr (denoted as V2 in FIG. 12), and the engine load factor LF is interlocked with this. (See step S8, time T2 in FIG. 12 (the engine load factor at this time is LF2)).

  As described above, when the control in which the deceleration amount vr is increased in proportion to the vehicle speed V before deceleration, if the vehicle speed V in the forward direction of the traveling machine body 1 is high, the engine load factor LF is quickly reduced by decelerating greatly. Can be lowered. If the vehicle speed V is low, the deceleration amount vr can be kept as small as possible to maintain the rotation of the cutting part and the threshing part, and thus maintain the efficiency of the cutting and threshing work. Therefore, it is possible to execute an appropriate vehicle speed control corresponding to the vehicle speed at that time, and to contribute to the efficiency of the cutting and threshing work.

  After the vehicle speed V in the forward direction of the traveling machine body 1 is decelerated by the deceleration amount vr, the detected value of the vehicle speed sensor 197 (vehicle speed V of the traveling machine body 1) and the detected value (engine load) of the rack position sensor 200 are again obtained. Reading (step S9), the current engine load factor LF is calculated based on the engine load (step S10).

  And it is discriminate | determined whether the present engine load factor LF calculated | required in step S10 is below the reset load factor LFb read in step S4 (step S11). When it is determined that the current engine load factor LF is equal to or lower than the return load factor LFb (S11: YES), it means that the engine load has been sufficiently reduced, and the cutting and threshing operation has not been hindered. Then, the process proceeds to step S15 described later.

  When it is determined that the current engine load factor LF is greater than the return load factor LFb (S11: NO, see time T3 in FIG. 12 (the engine load factor at this time is LF2)), the engine load is still sufficiently reduced. Since the vehicle speed V at the time of reading in step S9 and the relational expression or control map stored in advance in the ROM 192 of the controller 190, the deceleration amount vr at the time of executing the vehicle speed control is determined. (= A × V) is newly calculated (step S12).

  Next, whether or not the time T (standby time) after the deceleration operation of the traveling machine body 1 in step S8 is equal to or longer than the set standby time Tw, or the set standby time Tw has elapsed after the deceleration operation of the traveling machine body 1 is completed. It is determined whether or not (step S13).

  When the set standby time Tw has not elapsed (S13: NO), the process returns to step S13 again. When the set waiting time Tw has elapsed (S13: YES, when Tw = T3-T2 in FIG. 12), then, the electric motor 170 is driven to turn the straight HST transmission mechanism 35 for straight travel. By rotating the shaft 105 in the arrow SF direction (forward deceleration direction) via the linkage mechanism 171, a predetermined deceleration time Tr (Tr = T4-T3 in FIG. 12) is required, and the traveling direction of the traveling machine body 1 is increased. The vehicle speed V is decelerated by a deceleration amount vr in a predetermined time (denoted as V3 in FIG. 12), and in conjunction with this, the engine load factor LF is reduced again appropriately (step S14, time T4 in FIG. 12 (at this time) Refer to LF3) for engine load factor. Then, the process returns to step S9.

  That is, as is apparent from the series of steps S9 to S14, the forced deceleration operation of the traveling machine body 1 is repeated until the current engine load factor LF becomes equal to or less than the return load factor LFb.

  By controlling in this way, the engine load factor LF can be reliably reduced by repeating the forced deceleration operation. Therefore, even in the case of a normal combine with a heavy load fluctuation, the cutting portion 3 is clogged, the threshing portion 8 is reduced in rotation, and thus the engine. This is effective in suppressing the stop and further improving the effectiveness (stability) of the vehicle speed control.

  In step S15, since the current engine load factor LF is already equal to or less than the return load factor LFb, the time T ′ (standby time) after the deceleration operation of the traveling machine body 1 in step S14 is completed is the set standby time Tw. It is determined whether or not this is the case.

  When the set standby time Tw has not elapsed (S15: NO), the process returns to step S15 again. When the set waiting time Tw has elapsed (S15: YES, Tw = T5-T4 in FIG. 12), the electric motor 170 is driven to drive the rectilinear turning shaft 105 of the rectilinear HST transmission mechanism 35. Is rotated in the direction of the arrow SC (forward / deceleration direction) via the linkage mechanism 171, and the vehicle speed V in the forward direction of the traveling machine body 1 is changed to the original vehicle speed V1 corresponding to the forward tilting operation position of the main transmission lever 77 in a predetermined time. (See step S16, after time T5 in FIG. 12). After that, it returns.

  In the embodiment, since the standby time setting device 98 is disposed on the side panel body 76 in the control unit 5, the setting operation of the standby time setting device 98 causes the previous deceleration operation end point in the vehicle speed control to end. The waiting time Tw until the start of the next deceleration operation or return acceleration operation can be easily changed and adjusted.

  Therefore, when the mowing and threshing operation is desired to be performed as quickly as possible (smoothly), the set waiting time Tw may be shortened, and the traveling body 1 is prevented from proceeding in a state close to hunting, thereby improving ride comfort and driving safety. When improvement is desired, the set waiting time Tw may be lengthened. That is, the vehicle speed control can be executed in a state according to the work situation or the operator's preference.

  Further, since the load factor setting dial 83 is also arranged on the side panel body 76 in the control unit 5, whether or not the engine 6 is in an overload state by the setting operation of the load factor setting dial 83, that is, the traveling vehicle body 1. The reference value for determining whether or not the vehicle speed V in the forward direction is forcibly decelerated can be arbitrarily adjusted (in the range of 70 to 100% in the embodiment). For this reason, when executing the vehicle speed control, it is possible to easily adopt an appropriate setting according to the work situation, the operator's preference, and the like, and also in this respect, the vehicle speed control can be optimized.

  In the embodiment, by adopting a configuration in which when the set load factor LFa is determined, the return load factor LFb corresponding to this value is automatically determined, the manual setting for the return load factor LFb is omitted. . In this respect, it contributes to the suppression of the operation burden on the operator.

(8). Another Example of Vehicle Speed Control FIGS. 13 and 14 show another example of vehicle speed control. In this other example, after the controller 190 once executes control to decelerate the vehicle speed of the traveling machine body 1, the engine load factor LF obtained from the detection information of the rack position sensor 200 is larger than the return load factor LFb and the set load factor. When it becomes smaller than LFa (LFb <LF <LFa), the position of the rectilinear turning shaft 105 of the rectilinear HST transmission mechanism 35 is held, and the vehicle speed of the traveling machine body 1 is controlled so as to be maintained at that time. This is different from the above-described example. Other configurations are the same as the above-described example.

  The control mode from the start of vehicle speed control to step T10 in another example is the same as the control mode from the start to step S10 in the above example (see FIG. 11).

  After calculating the current engine load factor LF in step T10, it is determined whether or not the engine load factor LF is equal to or less than the return load factor LFb read in step T4 (step T11). When it is determined that the current engine load factor LF is equal to or less than the return load factor LFb (T11: YES), it means that the engine load is sufficiently reduced and there is no problem in the mowing and threshing work. Then, the process proceeds to step T16.

  In step T16, since the current engine load factor LF is already equal to or less than the return load factor LFb, the time T ′ (standby time) after the end of the previous deceleration operation of the traveling machine body 1 is the set standby time Tw. It is determined whether or not this is the case.

  When the set standby time Tw has not elapsed (T16: NO), the process returns to step T16 again. When the set standby time Tw has elapsed (T16: YES), the electric motor 170 is driven to drive the straight-traveling rotary shaft 105 of the straight-travel HST transmission mechanism 35 through the linkage mechanism 171 in the direction of the arrow SC ( The vehicle speed V in the forward direction of the traveling machine body 1 is returned and increased toward the original vehicle speed V1 corresponding to the forward tilting operation position of the main transmission lever 77 in a predetermined time (step T17). . Then return.

  On the other hand, if it is determined in step T11 that the current engine load factor LF is greater than the return load factor LFb (T11: NO), then whether or not the current engine load factor LF is equal to or greater than the set load factor LFa. Is determined again (step T12).

  When it is determined that the current engine load factor LF is equal to or greater than the set load factor LFa (T12: YES, refer to time T2 ′ in FIG. 14 (refer to engine load factor LF1 ′ at this time)), the engine load is still Since this means that the speed has not decreased, the deceleration amount at the time of executing the vehicle speed control is determined from the vehicle speed V read at step T9 and the relational expression or control map stored in advance in the ROM 192 of the controller 190. vr (= A × V) is newly calculated (step T13).

  Next, whether or not the time T (standby time) after the previous deceleration operation of the traveling machine body 1 is equal to or longer than the set standby time Tw, or the set standby time Tw has elapsed after the deceleration operation of the traveling machine body 1 is completed. Is determined (step T14).

  When the set standby time Tw has not elapsed (T14: NO), the process returns to step T14 again. When the set standby time Tw has elapsed (T14: YES, Tw = T3′−T2 ′ in FIG. 14), then, when the electric motor 170 is driven, the HST transmission mechanism 35 for straight travel is used for straight travel. A predetermined deceleration time Tr (Tr = T4′−T3 ′ in FIG. 14) is required by rotating the rotation shaft 105 in the direction of the arrow SF (forward deceleration direction) via the linkage mechanism 171, and the traveling machine body. The vehicle speed V in the forward direction of 1 is decelerated by a deceleration amount vr in a predetermined time (denoted as V3 ′ in FIG. 14), and the engine load factor LF is appropriately reduced again in conjunction with this (step T15, T4 ′ in FIG. 14). (Refer to LF2 ′ for the engine load factor at this time). Then, the process returns to step T9.

  That is, as is apparent from the series of steps T9 to T15, the forced deceleration operation of the traveling machine body 1 is repeated until the current engine load factor LF becomes equal to or less than the set load factor LFa.

  When it is determined in step T12 that the current engine load factor LF is smaller than the set load factor LFa (T12: NO), the engine load factor LF is larger than the return load factor LFb and smaller than the set load factor LFa. Therefore (see LFb <LF <LFa, time T4 ′ in FIG. 14 (the engine load factor at this time is LF2 ′)), and then, the position of the rectilinear rotation shaft 105 of the rectilinear HST transmission mechanism 35 is held. Thus, the vehicle speed V of the traveling machine body 1 is maintained at the time (the vehicle speed V read in step T9, expressed as V3 ′ in FIG. 14) (step T18). Then return.

  With this control, if the engine load factor LF is larger than the return load factor LFb and smaller than the set load factor LFa when the vehicle speed control is executed, the traveling vehicle body 1 maintains the predetermined vehicle speed V at that time. I will run. Therefore, fluctuations in vehicle speed during execution of the vehicle speed control are suppressed as much as possible, and deterioration of the riding comfort during execution of the control can be suppressed.

(9). Others The present invention is not limited to the above-described embodiment, and can be embodied in various forms. For example, the present invention is not limited to the conventional combine as described above, but can be widely applied to various work vehicles such as agricultural machines such as a self-propelled self-removing combine and a tractor and special work vehicles such as a crane truck. . Moreover, although all the engines employ | adopted for the above-mentioned embodiment were a diesel type thing, a gasoline type engine may be sufficient. In this case, the fuel injection pump is arranged at the position of the throttle valve for fuel adjustment in the carburetor. As a means for adjusting the movement position of the throttle valve, an actuator such as an electromagnetic solenoid that rotates a valve operating shaft attached to the throttle valve may be employed. The movement position detecting means of the throttle valve (corresponding to the load detecting means described in the claims) may be a rotation angle sensor such as a potentiometer that detects the rotation angle of the throttle valve.

  Further, in the above-described embodiment, the method of repeatedly decelerating until the engine overload is eliminated in the vehicle speed control is not limited to this, but if the vehicle is decelerated once in the vehicle speed control, then the return speed is increased. Needless to say, the deceleration operation and the return acceleration operation may have a one-to-one correspondence.

  In addition, the structure of each part is not limited to embodiment of illustration, A various change is possible in the range which does not deviate from the meaning of this invention.

It is a top view of a combine. It is a skeleton figure which shows the traveling drive system of a combine. It is a top view of a control part. It is a perspective view of a side column. It is explanatory drawing which shows typically the connection relation of a main speed-change lever, a steering handle, and a hydraulic drive means. It is a front view which shows the relationship between a detent means, a linkage mechanism, and an electric motor. FIG. 7 is a side sectional view taken along line VII-VII in FIG. 6. (A) is the figure which shows the state which rotated the detent rod for rectilinear advance in the forward acceleration direction, (b) shows the state which rotated the sector gear and the relay arm to the maximum forced deceleration position by the drive of the electric motor. FIG. 4C is a diagram showing a state in which the sector gear and the relay arm are returned and rotated to the initial positions by driving the electric motor. It is a functional block diagram of a controller. It is a figure of the control map which shows the relationship between the vehicle speed of a traveling body, and the deceleration amount. It is a flowchart which shows an example of vehicle speed control. It is a time chart which shows an example of vehicle speed control. It is a flowchart which shows another example of vehicle speed control. It is a time chart which shows another example of vehicle speed control.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Traveling machine body 2 Traveling crawler 3 Cutting part 5 Steering part 6 Engine 31 Hydraulic drive means 35 HST type speed change mechanism 36 for straight advance 1st hydraulic pump 37 1st hydraulic motor 38 HST type speed change mechanism 39 for turning 2nd hydraulic pump 40 1st 2 Hydraulic motor 70 Steering seat 73 Steering handle 76 Side panel body 77 Main shift lever 82 Automobile speed switch 83 Load ratio setting dial 92 Seat switch 94 Step switch 98 Standby time setting device 100 as standby time setting means Mechanical switching means 101 Double shaft 104 Straight-forward link mechanism 105 Straight-forward rotary shaft 106 Rotary link mechanism 107 Rotary rotary shaft 115 Straight-forward operation arm 116 Straight-forward interlocking rod 132 Straight-forward detent means 133 Rotary detent means 135 Straight-forward detent rod 135b Vertical flange 143 Torsion spring 170 Electric motor 171 Linking mechanism 173 Pinion gear 174 Sector gear 176 Relay arm 177 Linking rod 179 Guide groove hole 180 Pivot pin 190 Controller 194 as a vehicle speed control means Mowing clutch sensor 197 Vehicle speed sensor 198 Fuel injection pump 200 as fuel supply means 200 Load detection means as means Rack position sensor

Claims (3)

It is configured to transmit the power from the engine mounted on the traveling machine body to the working unit and the traveling unit via the hydraulic drive means,
Load detecting means for detecting a load of the engine in relation to fuel supply means to the engine;
Vehicle speed control means for executing vehicle speed control for decelerating the vehicle speed of the traveling machine body when the engine is overloaded and returning and increasing the vehicle speed of the traveling machine body to the original vehicle speed before deceleration when the overload is eliminated; ,
A standby time setting means for manually setting a standby time from the end of the previous deceleration operation to the next return acceleration operation start time in the vehicle speed control,
The vehicle speed control means controls to perform the next return acceleration operation after a preset standby time set in advance by the standby time setting means after the previous deceleration operation is completed. Work vehicle. It is configured to transmit the power from the engine mounted on the traveling machine body to the working unit and the traveling unit via the hydraulic drive means,
Load detecting means for detecting a load of the engine in relation to fuel supply means to the engine;
When the engine is overloaded, the vehicle speed of the traveling machine body is repeatedly reduced until the overload is eliminated, and when the overload is eliminated, the vehicle speed of the traveling machine body is restored and increased to the original vehicle speed before the deceleration. Vehicle speed control means for executing control;
A standby time setting means for manually setting a standby time from the end of the previous deceleration operation to the next deceleration operation or the return acceleration operation start time in the vehicle speed control,
The vehicle speed control means performs control so as to perform the next deceleration operation or return acceleration operation after a preset standby time set in advance by the standby time setting means after the previous deceleration operation is completed. A working vehicle characterized by A load factor setting means for manually setting a set load factor as a threshold value corresponding to when the engine is overloaded;
The vehicle speed control means determines that the engine is overloaded when the engine load factor obtained from the detection information of the load detection means is equal to or higher than the set load factor, and decelerates the vehicle speed of the traveling machine body,
When the engine load factor is equal to or less than the return load factor determined according to the set load factor value, it is determined that the engine overload has been resolved, and the vehicle speed of the traveling vehicle body is increased to the original vehicle speed before deceleration. The work vehicle according to claim 1, wherein the work vehicle is controlled so as to speed up.

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