JP2010187572A - Working vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To eliminate concern for causing breakage of an engine output shaft, burning out of transmission belt to a clutch resulting from a high torque occurring immediately after an operation unit drive in a working vehicle and to maintain and improve operation efficiency. <P>SOLUTION: The working vehicle transmits power from an engine mounted on a traveling machine body through a hydraulic continuously variable transmission to a traveling unit, and directly transmits the power to an operation unit, and the working vehicle includes an operation clutch for connecting and disconnecting a power transmission to the operation unit and a clutch operation member for operating connection and disconnection of the operation clutch. When the clutch operation member is engaged, the hydraulic continuously variable transmission is driven in an acceleration direction and the traveling speed of the traveling unit is maintained while reducing the number of revolutions of the engine to a preset target number of revolutions. <P>COPYRIGHT: (C)2010,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 continuously variable transmission, and this shift output is transmitted to a working unit such as a reaping unit or a threshing unit and a traveling unit. Are configured to communicate separately. It is known to perform constant rotation control (isochronous control) that keeps the engine speed at a constant rated speed even if the engine load fluctuates depending on the combine working condition, crop conditions, etc. (for example, patents) Reference 1). Such constant rotation control is performed in a range where the engine load does not exceed a predetermined value.

JP-A-10-89111

  By the way, in this type of combine, when a belt-tension type threshing clutch that interrupts power transmission to the threshing portion is engaged and operated during execution of constant rotation control, a high torque is generated immediately after the threshing portion is driven. . Since such a high torque places a heavy load on the transmission belt for the engine output shaft (crankshaft) and the threshing clutch, there is a concern that the output shaft may break or the transmission belt may burn out.

  As a measure for eliminating such a concern, there is a method of reducing the engine speed with the operation of engaging the threshing clutch. However, it is possible to prevent breakage of the output shaft, burnout of the transmission belt, and the like only by reducing the engine speed, but the traveling speed of the traveling machine becomes slow, so the efficiency of the cutting and threshing work is considered to be poor.

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

  The invention of claim 1 is configured to transmit power from an engine mounted on a traveling machine body to a traveling unit via a hydraulic continuously variable transmission, while transmitting directly to the working unit. A work vehicle having a working clutch for turning on / off power transmission to a section and a clutch operating member for operating on / off of the working clutch, and when the clutch operating member is turned on, The hydraulic continuously variable transmission is driven in the speed increasing direction while maintaining the traveling speed of the traveling unit while decreasing to a set target rotational speed.

  According to a second aspect of the present invention, in the work vehicle according to the first aspect, the work clutch is configured to be engaged and operated after the engine speed has decreased to the target speed.

  According to a third aspect of the present invention, in the work vehicle according to the first or second aspect, when the work clutch is engaged and operated, the engine speed is returned to the original speed before the decrease, and the hydraulic continuously variable transmission is performed. Is restored to the original drive amount before the speed increase, and the travel speed of the travel unit is maintained.

  According to the present invention, when the clutch operating member is engaged and operated, the hydraulic continuously variable transmission is driven in the speed increasing direction while lowering the engine speed to a preset target speed, and the running speed of the running section is increased. Therefore, even if the engine speed is reduced to the target speed, the traveling speed of the traveling unit does not slow down. For this reason, the generation of high torque immediately after the working unit is driven can be prevented to prevent breakage of the engine output shaft, burnout of the transmission belt to the working clutch (or generation of smoke due to friction), etc., and maintenance of working efficiency. There is an effect that improvement can be achieved.

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 the main transmission lever and a steering handle, and a hydraulic continuously variable transmission. It is a front view which shows the relationship between a detent means, a linkage mechanism, and an electric motor. It is a figure which shows the state which rotated the detent rod for rectilinear advance in the forward acceleration direction. It is a figure which shows the state which rotated the sector gear and the relay arm in the forward deceleration direction by the drive of the electric motor. It is a figure which shows the state which returned and rotated the sector gear and the relay arm to the initial position by the drive of the electric motor. It is a figure which shows the state which rotated the sector gear and the relay arm in the forward acceleration direction further by driving the electric motor, after rotating the detent rod for rectilinear advance in the forward acceleration direction. It is a functional block diagram of a controller. It is a flowchart which shows an example of control.

  DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments embodying the present invention will be described below with reference to the drawings when applied to a general combine as a work vehicle.

(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 changed by the hydraulic continuously variable transmission 31 or the like in the mission case 30, and left and right via the drive output shaft 60 protruding outward from the mission case 30 left and right. It is comprised so that it may output to the driving wheel 11 of this.

  In this case, in the transmission case 30, a hydraulic continuously variable transmission 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 gears. And a differential gear mechanism 33 having a planetary gear mechanism 51 and the like.

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

  Power from the output shaft 34 toward the hydraulic continuously variable transmission 31 is transmitted to the common pump shaft 41 of both the hydraulic pumps 36 and 39 outside the transmission case 30. In both of the straight and turning HST mechanisms 35 and 38, the 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 rectilinear HST 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. 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. ing.

  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 as to be switchable 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 rotatably supported by a carrier shaft 58 protruding outward from the outer side 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 mechanism 38, the inclination angle of the rotary swash plate of the second hydraulic pump 39 is changed according to the amount of turning operation of the steering handle 73 (details will be described later) arranged in the control unit 5. By adjusting and changing the discharge direction and discharge amount of the hydraulic oil to the second hydraulic motor 40, the rotation direction and the rotation speed of the turning motor shaft 61 protruding from the second hydraulic motor 40 are arbitrarily adjusted. It is configured.

  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 mechanism 38 is stopped, the left and right ring gears 57 are brought into 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 mechanism 35 is driven in a state where the drive of the turning HST mechanism 38 is stopped, the rotational power transmitted from the straight output gear 43 of the straight drive motor shaft 42 to the center gear 55 of the sun shaft 54 is left and right. Is transmitted to the sun gear 56 at the same rotational speed, and is output to the left and right drive output shafts 60 and 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.

  On the contrary, when the driving of the straight traveling HST mechanism 35 is stopped, the sun shaft 54 and the left and right sun gears 56 are in a locked state (fixed state) in which 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 mechanism 38 is driven in a state in which the driving of the straight traveling HST mechanism 35 is stopped, the rotational power from the turning motor shaft 61 is transmitted to the left ring gear 57 via the left rotation gear 64 and the reverse rotation gear 65. While rotating forward (reverse) at a predetermined rotational speed, 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. .

  That is, the rotational power from the turning HST 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 rotates forward. The other side rotates backward and the traveling machine body 1 spin-turns on the spot.

  Further, when the turning HST mechanism 38 is driven while the straight traveling HST 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 while rotating the spin turn turning radius. Turn left or right with a larger 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 as a clutch operating member are arranged in this 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 the straight traveling HST 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 other hand, 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 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 according to the working state, and adjusts the output of the hydraulic continuously variable transmission 31 (the rotational direction and the rotational speed of the linear motor shaft 42). Is set and held 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 as a clutch operating member serves as a lever for power transmission operation of the reaping part 3 and a lever for power transmission operation of the threshing part 8, and is a plane in the side panel body 76. It is configured to be tiltable in the left and right and front and rear directions along a substantially L-shaped guide groove 81.

  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 cutting clutch 205 and the threshing clutch 206 (see FIG. 11) are turned off, and the right end position (front and rear groove portions 81b) of the left and right groove portions 81a. The threshing clutch 206 alone is engaged when tilted to the rear end position), and the clutches 205 and 206 are both engaged when tilted to the front end position of the front and rear groove 81b.

  On the side panel body 76, various switches for operation and a plurality of dials for setting are also arranged. In the embodiment, the vehicle speed switch 82, the automatic cutting height switch 84, the cutting height setting dial 85, the automatic horizontal switch 86, and the inclination setting dial 87 are located in front of the main transmission lever 77 in the side panel body 76. Etc. 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 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 of main transmission lever / steering handle and hydraulic continuously variable transmission Next, a connection structure of the main transmission lever / steering handle and hydraulic continuously variable transmission 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 mechanism 35, and is an adjustment for adjusting the shift output of the rectilinear HST mechanism 35. It functions as a part. The turning shaft 107 for turning is for adjusting the inclination angle of the rotary swash plate of the second hydraulic pump 39 in the turning HST mechanism 38, and functions as an adjusting unit for adjusting the shift output of the turning HST mechanism 38. To do.

  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 to 12, the rectilinear rotation shaft 105 has a straight travel 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 rectilinear detent means 132, a substantially cylindrical boss member (not shown) is fitted on the rectilinear rotation shaft 105 as an adjusting portion of the rectilinear HST mechanism 35 so as to rotate integrally. . A midway portion of the straight detent rod 135 formed in a substantially Y-plate shape is fixed to the distal end portion of the rectilinear rotation shaft 105 with a nut.

  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 135 a formed on the upper end surface of the straight advance detent rod 135 is rotatably attached to the tip of the lateral arm portion 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 of the neutral holding arm 138 that is for straight movement and the vertical arm portion (details will be described later) of the neutral holding arm 158 that is for turning. Yes.

  On the other hand, a cylindrical member (not shown) that is rotatably fitted on the outer periphery of a boss member that rotates integrally with the rectilinear rotation shaft 105 is provided with a corner portion and a stopper of the substantially L-shaped rectilinear operation arm 115. The plate 142 is fixed. The distal end of the lateral arm portion 115a of the straight operation arm 115 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 oriented in the front-rear and lateral directions. 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 a return biasing means is fitted on the outer peripheral portion of the cylindrical member. 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.

  Further, a potentiometer-type straight traveling swash plate 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 rectilinear swash plate sensor 147 determines 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 operating pin 149 provided at the upper end of the rectilinear detent rod 135. It is to detect.

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

  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 155 a formed on the upper end surface of the turning detent rod 155 is rotatably attached to the tip of the lateral arm portion 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 cylindrical member (not shown) that is rotatably fitted on the outer periphery of a boss member that rotates integrally with the turning shaft 107 for turning is provided with a corner portion and a stopper of a substantially L-shaped turning operation arm 126. The plates 162 are fixed to each other. The distal end of the horizontal arm portion 126a of the turning operation arm 126 is pivotally attached to the other end portion (the lower end portion in the embodiment) of the turning interlocking rod 127 by a pivoting pin 131 that faces 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). Interlocking structure of electric motor and hydraulic continuously variable transmission Next, the interlocking structure of the electric motor and hydraulic continuously variable transmission will be described with reference to FIGS.

  An electric motor 170 serving as a speed change actuator is connected to an operation system (relay link mechanism 95, machine) from the main transmission lever 77 toward the straight rotation shaft 105. The automatic switching means 100 and the straight traveling link mechanism 104) are associated with each other through a separate linkage mechanism 171.

  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 sandwich the initial position shown in FIGS. 6 and 9 (the standby position when the vehicle speed control is not executed) by the rotation drive of the pinion gear 173 by the electric motor 170 in FIG. In the range from the maximum forced deceleration position to the maximum forced acceleration position in FIG. 10, it is configured to be rotatable around the pivot 175.

  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.

  As shown in FIGS. 6 and 9, 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, that is, the main transmission lever 77 is in the neutral position and the traveling machine body 1 is When stopped, the pivot pin 180 fixed to the relay arm 176 is set to be 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. 7). As a result, the vehicle speed in the forward direction of the traveling machine body 1 (the traveling speed of the left and right traveling unit 2) is increased under the condition where the engine speed N is constant.

  As shown in FIG. 7, 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 faces the pivot pin 180 on the relay arm 176 side. As a result, the pivot pin 180 is slid relatively to the vicinity of the lower edge of the guide slot 179 in the linkage rod 177 (the edge near the vertical flange 135b).

  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. 8), 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 reach the vertical shaft of the straight detent rod 135. Pushing downwardly toward the portion 135b, the detent rod 135 for rectilinear movement, and thus the rectilinear rotation shaft 105 is 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 (the traveling speed of the left and right traveling unit 2) is reduced under the condition that the engine speed N is constant.

  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 returns and pivots to the neutral position, and the rectilinear rotation shaft 105 and thus the first hydraulic pump 36 rotate. The swash plate is configured to move to a 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-running HST 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 part 3 and the threshing part 8 are driven to rotate. Therefore, even in the case of an ordinary combine with a heavy load fluctuation, clogging of the cutting part 3 and reduction in rotation of the threshing part 8 as well as engine stop can be reliably suppressed, and vehicle speed control effectiveness (stability) Will improve.

  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 rotary swash plate of the first hydraulic pump 36 is tilted in the forward deceleration direction during the execution of the vehicle speed control, the straight detent rod 135 (and hence the straight rotation shaft 105) moves in the direction of the arrow SF (forward deceleration). The straight operation arm 115 is held at a position corresponding to the forward tilting operation position of the main transmission lever 77 (see FIG. 8).

  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 executed, the rotary swash plate of the first hydraulic pump 36 is tilted in the forward deceleration direction, 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. When it is moved and returned to the initial position (see FIG. 9), the pivot pin 180 on the relay arm 176 side slides in the guide slot 179 of the linkage rod 177, and the lower edge of the guide slot 179 Leave the department.

  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 travel detent rod 135 and thus the straight travel rotation shaft 105 return and rotate at a moderate speed to the position of the portion 115b 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, under a condition where the engine speed N is constant, the vehicle speed in the forward direction of the traveling machine body 1 (the traveling speed of the left and right traveling unit 2) gradually decreases to the original vehicle speed corresponding to the forward tilting operation position of the main transmission lever 77. It speeds up.

  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 groove 179 slides relative to the vicinity of the lower edge (see FIG. 7).

  According to this configuration, the operator moves the front of the main speed change lever 77 in order to restore the vehicle speed after the vehicle speed in the forward direction of the traveling machine body 1 (the traveling speed of the left and right traveling unit 2) is forcibly decelerated by the vehicle speed control. There is no need to repeat the tilt operation. 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 (traveling speed of the left and right traveling unit 2) 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 speeds up rapidly. There is no safety.

  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.

  Further, as shown in FIGS. 6 to 10, a potentiometer type forced shift 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. The forced shift position sensor 182 is arranged so that the position of the pivot pin 180 and the sector gear 174 is determined based on the rotation angle of the sensing arm 183 caused by the contact of the rotation plate 184 fixed to the pivot 175 and the operation pin 185 separately from the relay arm 176. Is detected.

  In the state shown in FIG. 7 in which the vehicle speed switch 82 is turned on and the main transmission lever 77 is tilted forward from the neutral position, the relay arm 176 and the sector gear 174 are initialized by the rotational drive of the pinion gear 173 by the electric motor 170. When the pivot pin 180 on the relay arm 176 side is slid in the guide groove hole 179 of the linkage rod 177 by rotating in the arrow BA direction from the position toward the maximum forced acceleration position (see FIG. 10), the guide The upper end of the slot 179 is hit and the connecting rod 177 is lifted obliquely upward. Then, the straight travel detent rod 135 and the straight travel rotation shaft 105 rotate in the direction of the arrow SC (forward speed increase direction), and the vehicle speed in the forward direction of the traveling machine body 1 (left and right travel) under a condition where the engine speed N is constant. The traveling speed of part 2 is increased.

  In the embodiment, when the operation to enter the threshing clutch is performed with the clutch lever 79 during execution of the vehicle speed control, the engine speed N is set to suppress the generation of high torque immediately after the threshing unit 8 is driven. While reducing to a preset target rotational speed N0, the straight detent rod 135 and, consequently, the rectilinear rotation shaft 105 is rotated in the direction of the arrow SC (forward speed increasing direction) to thereby rotate the swash plate of the first hydraulic pump 36. Is tilted in the forward speed increasing direction. For this reason, even if the engine speed N is reduced to the target speed N0, the vehicle speed in the forward direction of the traveling machine body 1 (the traveling speed of the left and right traveling unit 2) can be maintained.

  According to such a configuration, even when the engine speed N is reduced to the target speed N0 when the operation for entering the threshing clutch is performed with the clutch lever 79 during the execution of the vehicle speed control, the traveling machine body 1 The vehicle speed in the forward direction (the traveling speed of the left and right traveling unit 2) does not slow down. Accordingly, the generation of high torque immediately after the threshing unit 8 is driven to prevent breakage of the output shaft 34, burnout of the transmission belt (or generation of smoke due to friction), etc. It can be maintained and improved.

  When the rotational swash plate of the first hydraulic pump 36 is tilted in the forward speed increasing direction during the execution of the vehicle speed control, the straight travel detent rod 135 (and hence the straight travel rotation shaft 105) is subjected to the biasing force of the torsion spring 143. In contrast, although it rotates in the direction of the arrow SC (forward acceleration direction), the linear operation arm 115 is held at a position corresponding to the forward tilting operation position of the main transmission lever 77 (see FIG. 10).

  Therefore, the rotational force of the straight travel detent rod 135 in the direction of the arrow SC (forward speed increase 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. There is no inconvenience that the main speed change lever 77 moves without permission each time the traveling machine body 1 is forcibly increased during execution.

  When the vehicle speed control is executed, the rotary swash plate of the first hydraulic pump 36 is tilted in the forward speed increasing direction, and then the relay arm 176 and the sector gear 174 are moved in the direction of the arrow RE by the rotational drive of the pinion gear 173 by the electric motor 170. When it is rotated and returned to the initial position (see FIG. 7), the pivot pin 180 on the relay arm 176 side slides in the guide groove hole 179 of the linkage rod 177, and above the guide groove hole 179. Move away from the edge.

  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 is away from the upper edge of the guide slot 179. With this elastic restoring force, the vertical arm in the straight operation arm 115 is provided. The straight travel detent rod 135 and thus the straight travel turning shaft 105 return and rotate at a moderate speed to the position of the portion 115b, and return to the state shown in FIG.

  The return rotation position of the straight detent rod 135 at this time is the original position before the forced acceleration corresponding to the forward tilting operation position of the main transmission lever 77 (the relay arm 176 and the sector gear 174 are rotated in the direction of the arrow BA). Previous position). As a result, under the condition that the engine speed N is constant, the vehicle speed in the forward direction of the traveling machine body 1 (the traveling speed of the left and right traveling unit 2) gradually decreases to the original vehicle speed corresponding to the forward tilting operation position of the main transmission lever 77. Will slow down.

  In this case, the linkage rod 177 is pushed obliquely downward toward the vertical rod portion 135b of the straight advance detent rod 135 by the return rotation of the straight advance detent rod 135 in the direction of the arrow SF, and the pivot pin 180 is moved to the linkage rod. Needless to say, the guide groove 179 slides relatively near the lower edge of the guide groove 179 (see FIG. 7).

  In the embodiment, when the operation of entering the threshing clutch is performed with the clutch lever 79 and the threshing clutch is engaged and operated during execution of the vehicle speed control, the engine speed N is returned to the original speed Nb before the decrease. At the same time, the detent rod 135 for rectilinear movement and then the rotation shaft 105 for rectilinear movement are rotated back at a moderate speed to the position of the vertical arm 115b in the operation arm 115 for rectilinear movement, thereby forcing the rotary swash plate of the first hydraulic pump 36. It is configured to return to the original angle (drive amount) before the speed increase. For this reason, after driving the threshing unit 8 without causing breakage of the output shaft 34 or burning of the transmission belt, the vehicle speed in the forward direction of the traveling machine body 1 (the traveling speed of the left and right traveling unit 2) is maintained. Therefore, it is possible to smoothly shift to the next work (cutting and threshing work) without bothering the operator's hand, and the efficiency of the cutting and threshing work can be improved while reducing the operation burden on the operator. In addition, even when the engine speed N is changed, the riding comfort of the traveling machine body 1 can be maintained satisfactorily and safety is ensured.

(6). Configuration of Control Unit and Control Mode Thereof Next, a configuration for executing vehicle speed control and the like of the traveling machine body and an example of the control mode will be described with reference to FIGS. 11 and 12.

  A controller 190 such as a microcomputer as a control means mounted on the traveling machine body 1 includes a central processing unit 191 (CPU) for executing various arithmetic processes and controls, and a read-only memory 192 for storing control programs and data. (ROM), read / write memory 193 (RAM) for temporary storage of control programs and data, clock as a timer function, input / output for exchanging data with each input / output device (sensor, actuator, etc.) An interface (not shown) is provided. The ROM 192 of the controller 190 stores in advance a target rotational speed N0 that is used when executing control to be described later.

  The input interface of the controller 190 includes, for example, an automobile speed switch 82, 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, an accelerator dial 89, a reel height. Length adjustment dial 90, reel shift automatic switch 91, straight traveling swash plate sensor 147, auxiliary transmission lever 78, cutting clutch sensor 194 for detecting the on / off state of the power transmission cutting clutch 205 with respect to the cutting unit 3, a threshing unit 8, a threshing clutch sensor 195 for detecting the on / off state of the threshing clutch 206 for power transmission, a forced shift position sensor 182, a seat switch 92, left and right step switches 94, and an engine for detecting the rotational speed of the engine 6. 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 charge supply means, a power switch 201 for turning on and off the entire combine, etc. are connected. ing.

  On the other hand, the output interface of the controller 190 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.

  The controller 190 according to the embodiment can execute control to increase / decrease the engine speed N and the drive amount of the straight traveling HST mechanism in opposite directions when the clutch lever 79 is operated to enter the threshing clutch 206. It is configured. When executing such control, the vehicle speed switch 82 is in the on state.

  In this case, as shown in the flowchart of FIG. 12, when the clutch lever 79 is operated to enter the threshing clutch 206 (step S1: YES), the vehicle speed Vb detected by the vehicle speed sensor 197 and the engine rotation are detected. The engine speed Nb detected by the sensor 196 is stored in the RAM 193 of the controller 190 (step S2). Next, the fuel injection amount from the fuel injection pump 199 is reduced to lower the engine speed N to the target speed N0. In conjunction with this, when the pinion gear 173 is driven to rotate by the electric motor 170, the straight detent rod 135 and the straight rotation shaft 105 are moved in the direction of the arrow SC by an amount corresponding to the deceleration amount of the vehicle speed accompanying the decrease in the engine speed. The rotation swash plate of the first hydraulic pump 36 is tilted in the forward acceleration direction (step S3). As a result, even if the engine speed N is reduced to the target speed N0, the vehicle speed Vb in the forward direction of the traveling machine body 1 (the traveling speed of the left and right traveling unit 2) is maintained.

  Next, it is determined whether or not the engine speed N has decreased to the target speed N0. If the engine speed N has decreased to the target speed N0 (step S4: YES), a threshing clutch that turns power transmission to the threshing unit 8 on and off. 206 is entered and operated (step S5). Then, the fuel injection amount from the fuel injection pump 199 is increased, and the engine speed N is restored to the engine speed Nb stored previously. Then, in conjunction with this, the rotation of the pinion gear 173 by the electric motor 170 rotates the rectilinear detent rod 135 and thus the rectilinear pivot shaft 105 back in the direction of the arrow SF (forward deceleration direction), and thereby the first hydraulic pressure The rotary swash plate of the pump 36 is returned to the original angle (drive amount) before the forced acceleration (step S6). As a result, even if the engine speed N is increased to the original speed Nb, the vehicle speed Vb in the forward direction of the traveling machine body 1 (the traveling speed of the left and right traveling unit 2) is maintained.

  As is clear from the above description, in the embodiment, when an operation for entering the threshing clutch 206 is performed with the clutch lever 79 during execution of the vehicle speed control, generation of high torque immediately after the threshing unit 8 is driven is generated. In order to suppress this, the linear speed HST mechanism 35 is driven in the forward speed increasing direction while maintaining the traveling speed of the left and right traveling unit 2 while reducing the engine speed N to a preset target speed N0. Therefore, even if the engine speed N is decreased to the target speed N0, the vehicle speed in the forward direction of the traveling machine body 1 (the traveling speed of the left and right traveling unit 2) does not slow down. For this reason, generation | occurrence | production of the high torque immediately after the threshing part 8 drive is suppressed, and it can prevent breakage of the output shaft 34 or burnt-out of the transmission belt (or generation of smoke due to friction), etc. Improvements can be made.

  In addition, since the threshing clutch 206 is configured to be engaged and operated after the engine speed N has decreased to the target speed N0, the threshing unit 8 can be smoothly driven using the low speed range of the engine 6. It is possible to start (slowly), and it is possible to reliably prevent the occurrence of an excessive load due to sudden driving of the threshing unit 8 or the like. For this reason, a high effect can be exhibited in preventing breakage of the output shaft 34, burnout of the transmission belt (or generation of smoke due to friction), and the like.

  Furthermore, when the threshing clutch 206 is engaged and operated by performing an operation to enter the threshing clutch 206 with the clutch lever 79 during execution of the vehicle speed control, the engine speed N is returned to the original speed Nb before the decrease. In addition, since the HST mechanism 35 for straight traveling is configured to maintain the traveling speed of the left and right traveling unit 2 by returning to the original angle before the forced acceleration (the driving amount, the transmission shaft 34 is broken or the transmission belt is After driving the threshing unit 8 without incurring burnout, the vehicle speed in the forward direction of the traveling machine body 1 (the traveling speed of the left and right traveling unit 2) is maintained and the next operation is performed without bothering the operator. Therefore, the efficiency of the cutting and threshing work can be improved while reducing the operation burden on the operator, and even if the engine speed N is changed, the traveling machine body 1 Ri comfort can be maintained at a satisfactory level, it is the also ensures safety.

(7). 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 above-described ordinary combine, but can be widely applied to various work vehicles such as agricultural machines such as self-propelled self-moving combiners and tractors, and special work vehicles such as crane trucks. . 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 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.

DESCRIPTION OF SYMBOLS 1 Traveling machine body 2 Traveling crawler 6 as traveling part Engine 8 Threshing part 31 Hydraulic continuously variable transmission 35 HST mechanism for straight advance 38 HST mechanism for turning 79 Clutch lever 82 as clutch operating member Automobile speed switch 115 Straight forward operating arm 116 Straight forward Interlocking rod 132 Straight detent means 133 Turning detent means 135 Straight traveling detent rod 135b Vertical hook portion 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 Pivoting pin 190 Controller as control means

Claims (3)

It is configured to transmit power from the engine mounted on the traveling machine body to the traveling unit via the hydraulic continuously variable transmission, while directly transmitting it to the working unit. A work vehicle comprising: a work clutch that operates; and a clutch operation member that operates turning on and off of the work clutch,
When the clutch operating member is engaged and operated, the hydraulic continuously variable transmission is driven in the speed increasing direction while maintaining the traveling speed of the traveling unit while lowering the engine rotational speed to a preset target rotational speed. Configured as
Work vehicle. The engine clutch is configured to enter and operate after the engine speed has decreased to the target speed.
The work vehicle according to claim 1. When the working clutch is engaged and operated, the engine speed is returned to the original speed before the decrease, and the hydraulic continuously variable transmission is returned to the original drive amount before the speed increase, so that the traveling portion travels. Configured to maintain speed,
The work vehicle according to claim 1 or 2.

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