JP2009047044A - Travel control mechanism - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a travel control mechanism capable of effectively preventing sudden starting of a work vehicle. <P>SOLUTION: When a shift stage of a sub-transmission 19 is a predetermined shift stage or more when starting a tractor 1, a control device 700 transfers to starting control, and an electronic governor mechanism 701 is controlled so that engine output becomes minimum regardless of an operation state of a governor operation member (a throttle pedal 330 and a throttle lever 141) of the tractor 1. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention includes an engine having a governor mechanism, a governor operating member for artificially operating the governor mechanism, and a clutch device and a multi-stage transmission device inserted in a traveling system transmission path from the engine to drive wheels. The present invention relates to a traveling control mechanism applied to a working vehicle.

As a travel control mechanism applied to a working vehicle such as a tractor, an engine having a governor mechanism, a governor operation member for artificially operating the governor mechanism, and a travel system transmission path from the engine to a drive wheel are inserted. A device including a clutch device and a multi-stage transmission is known.
As a governor operating member for manipulating the governor mechanism, a lever position is maintained at a predetermined operation position (a predetermined engine output is maintained) and a minimum output side when not operated There is known one provided with a throttle pedal (foot accelerator pedal) that automatically returns to the (idling side) (for example, see Patent Document 1). The multi-stage transmission is manually operated using a shift lever for manually operating the multi-stage transmission.

In such a conventional travel control mechanism, when the vehicle is started (starting), the clutch device is in a state where the engine speed is high and the multi-stage transmission is engaged with the high speed side stage by the governor operating member. When engaged, there is a problem that the working vehicle starts suddenly. If the work vehicle suddenly starts, it is not preferable because the vehicle is shaken back and forth, the vehicle posture becomes unstable, or the front wheel is lifted (willy state) and becomes unsteerable.
JP-A-9-250365

  The present invention has been made in view of the above prior art, and an object thereof is to provide a travel control mechanism that can effectively prevent a sudden start of a work vehicle.

  In order to achieve the above object, one aspect of the traveling control mechanism according to the present invention includes an engine having an electronic governor mechanism, a governor operating member for artificially operating the electronic governor mechanism, and A work vehicle comprising a control device that performs normal control for operating the electronic governor mechanism in response to human operation, and a clutch device and a multi-stage transmission device that are inserted in a traveling transmission path from the engine to a drive wheel. An applied travel control mechanism includes a shift speed detection sensor that detects a shift speed of the multi-speed transmission, and the control device is configured to operate the vehicle in a state where the multi-speed transmission is engaged at a predetermined speed or higher. When the vehicle is started by engaging the clutch device from a stopped state, the electronic governor mechanism is used in place of the normal control regardless of the manual operation of the governor operating member. It is characterized in carrying out the control to start control to the lowest output state.

According to the travel control mechanism having the above-described configuration, during normal control by the control device, the governor operating member is manually operated, and the electronic governor mechanism of the engine is activated according to the manual operation of the governor operating member, and the engine output is increased. Be controlled.
Here, in a vehicle stop state, when the shift speed of the multi-speed transmission detected by the shift speed detection sensor is engaged at a predetermined shift speed or higher, the control device shifts from the normal control to the start control, The electronic governor mechanism is forced to the minimum output state regardless of the manual operation position in the governor operation member. As a result, even when the vehicle is started with the clutch device engaged, the vehicle starts (starts) with the engine output held at the minimum output.

  Thus, when the speed of the multi-stage transmission is greater than or equal to a predetermined speed at the start of the vehicle, the electronic governor mechanism is set so that the engine output is minimized regardless of the operating state of the governor operating member of the vehicle. Since the vehicle is controlled, sudden start of the vehicle can be effectively prevented, and the vehicle posture can be kept stable.

  Preferably, the control device shifts to the normal control when the governor operating member is positioned at the lowest output position after the start control is executed.

In this case, after the vehicle is started by the start control, if the governor operating member is manually operated so as to be positioned at the lowest output position, the control device shifts from the start control to the normal control, and the operation state of the governor operating member is changed. Accordingly, the engine output is controlled to be changeable.
In this way, since the start control is canceled by positioning the governor operating member at the minimum output position, the vehicle speed is suddenly changed during the transition from the start control in which the engine output is restricted to the normal control in which the restriction is released. Change can be prevented, and the vehicle posture at the time of transition can be kept stable.

  In another aspect of the travel control mechanism according to the present invention, an engine having a governor mechanism, a governor operating member for artificially operating the governor mechanism, an operation link that operatively connects the governor operating member and the governor mechanism. A travel control mechanism applied to a work vehicle comprising a mechanism and a clutch device and a multi-stage transmission device inserted in a travel system transmission system path from the engine to the drive wheel, wherein the shift stage of the multi-stage transmission device A shift speed detection sensor that detects the shift speed, a governor actuator that directly or indirectly operates the governor mechanism, and a control device that controls the governor actuator based on a signal from the shift speed detection sensor, Is engaged with the clutch device from a vehicle stop state in a state where the multi-stage transmission is engaged at a predetermined speed or more. When to be moving is characterized in that performing the starting control in which the actuates the governor actuator to forcibly lowest output state the governor mechanism.

According to the travel control mechanism having the above-described configuration, when the governor operating member is manually operated, the engine governor mechanism is operated according to the manual operation of the governor operating member via the operation link mechanism, and the engine output is changed. The
Here, when the speed of the multi-speed transmission detected by the speed detection sensor is engaged at a predetermined speed or higher when the vehicle is stopped, the control device performs start control and operates the governor actuator. As a result, the governor mechanism operates directly or indirectly, and is forced to the minimum output state. As a result, even when the vehicle is started with the clutch device engaged, the vehicle starts (starts) with the engine output held at the minimum output.

  Thus, when the speed of the multi-stage transmission is greater than or equal to a predetermined speed at the start of the vehicle, the governor mechanism is operated so that the governor actuator is actuated by the controller and the engine output is forcibly minimized. Since the vehicle is controlled, sudden start of the vehicle can be effectively prevented, and the vehicle posture can be kept stable.

  Preferably, the control device shifts the governor actuator to an initial state after elapse of a predetermined time set in advance or after reaching a predetermined vehicle speed set in advance to perform an artificial operation on the governor operating member. Is possible.

In this case, when the vehicle is started by the start control, the governor operating member operatively connected to the governor mechanism is forcibly positioned at the minimum output position by the governor actuator. In this state, after the vehicle has been started by the start control, when a preset time has elapsed, or when a preset vehicle speed has been reached, the control device shifts the governor actuator to the initial state, The engine output can be changed according to the operating state of the governor operating member.
In this way, after starting the vehicle, the engine control is changed immediately after the start or when the vehicle speed is low when the start control is canceled by canceling the start control when a predetermined time elapses or reaches a predetermined speed. Can be prevented, and the vehicle posture at the time of transition can be kept stable.

According to one aspect of the travel control mechanism according to the present invention, when a vehicle equipped with an engine having an electronic governor mechanism is started, when the speed of the multi-stage transmission is greater than or equal to a predetermined speed, the vehicle governor operation is performed. Regardless of the operation state of the members, the electronic governor mechanism is controlled so that the engine output becomes the lowest, so that sudden start of the vehicle can be effectively prevented and the vehicle posture can be kept stable.
Further, according to another aspect of the travel control mechanism according to the present invention, when the shift stage of the multi-stage transmission is greater than or equal to a predetermined shift stage at the start of the vehicle in which the governor operating member and the governor mechanism are operatively connected, Since the governor mechanism is controlled so that the engine output is forcibly minimized by the governor actuator, the sudden start of the vehicle can be effectively prevented, and the vehicle posture can be kept stable.

Hereinafter, a preferred embodiment of a travel control mechanism according to the present invention will be described with reference to the accompanying drawings.
1 and 2 are a left side view and a right side view of a tractor 1 to which a traveling control mechanism according to a first embodiment of the present invention is applied. FIG. 3 is a view showing a transmission mechanism of the tractor 1 to which the traveling control mechanism according to the first embodiment of the present invention is applied.

As shown in FIGS. 1 and 2, the tractor 1 that is a working vehicle is configured to transmit power from the engine 10 that is a drive source to the output unit 30 via the transmission unit 20.
In the present embodiment, the tractor 1 has a drive axle 31 and a PTO shaft 29 (see FIG. 3) as the output unit 30.
Therefore, the transmission unit 20 is configured to transmit the power from the engine 10 to the drive axle 31 and also to the PTO shaft.

  The transmission unit 20 includes a front housing H1, an intermediate housing H2, and a rear housing H3 that are coupled along the vehicle longitudinal direction. The front housing H1, the intermediate housing H2, and the rear housing H3 form part of the airframe in the tractor 1. The front housing H1 has a supporting wall portion 1a provided integrally at the middle portion in the front-rear direction. Further, the front housing H1 is attached and supported inside the front housing H1 at a position where the portion of the front housing H1 located behind the supporting wall portion 1a is substantially divided in the front-rear direction. 1 bearing frame 4 and a second bearing frame 5 attached to and supported by the rear end of the front housing H1. The second bearing frame 5 may be attached and supported on the front end of the intermediate housing H2. The intermediate housing H2 has a supporting wall portion 2a provided integrally at the intermediate portion in the front-rear direction. The rear housing H3 includes a front wall 3a, a support wall 3b in the middle in the front-rear direction, and a rear lid 3c that closes the opening at the rear end. Further, in the front housing H1, there is provided a clutch device 2 inserted in a traveling system transmission system path from the engine 10 to a drive wheel (drive axle 31). The clutch device 2 includes a clutch body 7 that is operatively connected to the engine 10 via a flywheel 6, and a driving shaft 8 that is operatively connected to the output side of the clutch body 7. Is supported in the front housing H1.

The clutch body 7 is configured to be able to engage or block power transmission from the engine 10 to the driving shaft 8 in accordance with an operation of the following clutch pedal 155 provided near the driver's seat.
The traveling system transmission mechanism in the tractor 1 includes a forward / reverse switching device 3, a high / low speed switching device 13, a main transmission device 16, and an auxiliary transmission device 19, which are connected in series.
The forward / reverse switching device 3 includes a driving shaft 8 and a driven shaft 9 disposed parallel to the driving shaft 8 (downward in the illustrated form) between the support wall 1a and the first bearing frame 4. It is arranged in between. The high / low speed switching device 13 is disposed between the first bearing frame 4 and the second bearing frame 5 on the extension line of the driven shaft 9 and is connected to the driven shaft 9 and the driving shaft 8. It arrange | positions between the hollow driven shafts 12 arrange | positioned on the extension line.
The main transmission 16 is disposed on the extension line of the driven shaft 12 in the front half of the intermediate housing 2 and is connected to the hollow drive shaft 14 and the extension line of the drive shaft 47 connected to the driven shaft 12. 15.
The auxiliary transmission 19 includes a driven shaft 15, a hollow counter shaft 17 operatively connected to the driven shaft 15, and a propeller shaft disposed on an extension line of the driven shaft 15 in the rear half of the intermediate housing 2. 18. The hollow counter shaft 17 is disposed on an extension line of the drive shaft 14.
The rear end of the propeller shaft 18 extends into the rear housing H3, and a small bevel gear 21 that meshes with the input bevel gear 49 of the differential gear mechanism for the left and right rear wheels is provided at the rear end. ing. Further, a front wheel driving force take-out case 22 that outputs rotational power toward the front axle 32 that is a sub driving shaft is attached to the bottom of the intermediate housing H2. A front wheel driving force extraction shaft 23 is supported on the front wheel driving force extraction case 22, and the front wheel driving force extraction shaft 23 is connected to the propeller shaft 18 via a front wheel driving clutch 24.

The PTO transmission mechanism in the tractor includes a transmission shaft 25 having a front end connected to the driving shaft 8, the transmission shaft 25 penetrating the hollow driven shaft 12, the hollow drive shaft 14 and the hollow counter shaft 17, A transmission shaft 26 provided in the rear housing H3 so as to be connected to the rear end of the transmission shaft 25, another transmission shaft 27 disposed on an extension line of the transmission shaft 26, the transmission shaft 26 and the transmission shaft 27, a PTO clutch 28 disposed between the PTO shaft 29, a PTO shaft 29 disposed in parallel to the transmission shaft 27 (lower in the illustrated embodiment), and a rear end extending rearward from the rear lid 3c; And a PTO transmission 50 having three speeds disposed between the transmission shaft 27 and the PTO shaft 29.
Further, the PTO transmission mechanism includes a transmission shaft 31 operatively connected to the propeller shaft 18 and a ground PTO clutch 52 disposed between the transmission shaft 51 and the PTO shaft 29. .
Further, a hydraulic lift device 33 having left and right lift arms 33a for raising and lowering a working machine (not shown) driven by the PTO shaft 29 is installed on the upper surface of the rear housing H3.

The forward / reverse switching device 3 has two gears 34 and 35 loosely fitted to the driving shaft 8 and two gears 36 and 37 fixed to the driven shaft 9. The gears 34 and 36 are directly meshed, and the gears 35 and 37 are meshed via an intermediate idler gear (not shown).
The forward / reverse switching device 3 further includes a forward hydraulic clutch 40F and a reverse hydraulic clutch 40R fixedly installed on the driving shaft 8 between the gears 34 and 35. The forward hydraulic clutch 40F and the reverse hydraulic clutch 40R are provided in a common clutch cylinder.
Each of the hydraulic clutches 40F and 40R is a known friction multi-plate clutch. In such a configuration, when the forward hydraulic clutch 40F is engaged and the gear 34 is operatively connected to the driving shaft 8, the driven shaft 9 rotates in the vehicle forward direction. Conversely, when the reverse hydraulic clutch 40R is engaged and the gear 35 is operatively connected to the driving shaft 8, the driven shaft 9 rotates in the vehicle reverse direction.

The high / low speed switching device 13 includes two gears 43 and 44 loosely fitted to the drive shaft 47 and two gears 45 and 46 fixed to the driven shaft 12. The gears 43 and 44 are engaged with the gears 45 and 46, respectively.
The high / low speed switching device 13 further includes a high speed hydraulic clutch 48H and a low speed hydraulic clutch 48L disposed on the drive shaft 47 so as to be positioned between the gears 43, 44.
The high speed hydraulic clutch 48 </ b> H and the low speed hydraulic clutch 48 </ b> L include a common clutch cylinder fixedly installed on the drive shaft 47.
The high speed hydraulic clutch 48H is a hydraulically operated friction multi-plate clutch, and the low speed hydraulic clutch 48L is a spring-operated friction multi-plate clutch.

  The drive shaft 47 is provided with a hydraulic oil passage that is shared by the high speed hydraulic clutch 48H and the low speed hydraulic clutch 48L. The high speed hydraulic clutch may or may not be supplied with pressure oil in the hydraulic oil passage. Either 48H or the low speed hydraulic clutch 48L is alternatively engaged.

  When the hydraulic pressure is applied to the hydraulic clutches 48H and 48L, the high / low speed switching device 13 of the present embodiment engages the high speed hydraulic clutch 48H, releases the low speed hydraulic clutch 48L, and releases the hydraulic clutches 48H and 48L. On the other hand, when the action of the hydraulic pressure is released, the high speed hydraulic clutch 48H is released, and the low speed hydraulic clutch 48L is engaged.

As shown in FIG. 1, the main transmission 16 includes four gears 53, 54, 55, 56 fixed to the drive shaft 14 and four gears 57, 58, loosely fitted to the driven shaft 15. 59, 60. The fixed gears 53 to 56 are meshed with the corresponding loosely fitted gears 57 to 60.
Further, the main transmission 16 includes two double synchronous clutches 61 and 62 provided on the driven shaft 15 so as to be positioned between the gears 57 and 58 and between the gears 59 and 60. Is selectively coupled to the driven shaft 15 so as to obtain a four-speed shift.

As shown in FIG. 1, the auxiliary transmission 19 includes gear trains 64 and 65 for reducing and connecting the driven shaft 15 to the counter shaft 17, two gears 66 and 67 fixed to the counter shaft 17, A gear 69 connected to the small-diameter side gear 67 via a reduction gear mechanism 68, which is supported by a gear 69 other than the counter shaft 17, so that it can selectively mesh with the gears 69, 67. , A shift gear 70 which is not rotatable relative to the propeller shaft 18 and is slidable in the axial direction, a gear 71 loosely fitted on the propeller shaft 18 so as to mesh with the gear 66, and the gear 71 with respect to the propeller shaft 18. A double clutch 72 is provided which is operated to a position for coupling, a position for directly connecting the propeller shaft 18 to the driven shaft 15, and a neutral position.
The sub-transmission 19 having such a configuration includes the first speed in which the gears 69 and 70 are engaged with the double clutch 72 positioned at the neutral position, and the gears 67 and 70 with the dual clutch 72 positioned at the neutral position. , And the third speed in which the propeller shaft 18 is coupled to the gear 71 by the double clutch 72, and the fourth speed in which the propeller shaft 18 is directly connected to the driven shaft 15 by the double clutch 72. The propeller shaft 19 can be selectively obtained.

Here, the traveling control mechanism of the tractor 1 will be described.
In FIG. 4, the block diagram of the traveling control mechanism in this embodiment is shown.
FIG. 5 shows a perspective view of the engine unit viewed from the left rear. FIG. 6 is a perspective view of the engine unit and the transmission unit as viewed from the right rear. 5 and 6 show a state where the dashboard portion is removed.
As shown in FIGS. 1, 2, 5, and 6, the engine unit includes the engine 10, the steering unit 110, the dashboard unit 120, the operation lever unit 130, the operation pedal unit 150, and a bonnet support. Part 170, a fuel tank part 180, and a dashboard stay 100 connected to the rear surface of the engine 10, and the steering part 110 is supported by the engine 10 via the dashboard stay 100. ing.

Specifically, the dashboard stay 100 includes a mounting plate 101 connected to the rear surface of the engine in a substantially vertical state along the vehicle width direction, and a mounting plate 101 in a state substantially vertical and along the vehicle front-rear direction. It has a pair of left and right support plates 102a and 102b extending to the rear side.
In the present embodiment, the mounting plate 101 is wider in the vehicle width direction than the engine 10. And the lower end part of the part which protrudes to the vehicle width direction outward from the said engine 10 among the said mounting plates 101 is supported by the reinforcement board 109 respectively connected with the both sides | surfaces of the said engine 10. FIG.

  As shown in FIGS. 4 and 6, the engine 10 is provided with an electronic governor mechanism 701, and the output (rotation speed) of the engine 10 is changed according to the operation of the electronic governor mechanism 701.

  As shown in FIGS. 5 and 6, the steering unit 110 has a valve block 111 connected between the rear portions of the pair of support plates 102a and 102b, and a lower end portion extending substantially in the vertical direction. A steering column 112 inserted into the steering column 112 with a hollow steering column 112 connected to the block 111 and a power steering valve (not shown) housed in the valve block 111 at its lower end. A shaft 113 and a steering wheel 114 connected to the upper end portion of the steering shaft 113 so as not to rotate relative to each other are provided.

  As shown in FIGS. 5 and 6, the operation pedal unit 150 includes a hollow support member 151 supported by the dashboard stay 100, and the hollow support member 151 with both ends extending outward. The pedal shaft 152 that is inserted, the clutch boss 153 that is externally rotatably inserted into one end side extension portion (the left end portion in the illustrated form) of the pedal shaft 152, and the clutch boss 153 are supported by the clutch boss 153. The clutch arm 154, the clutch pedal 155 provided at the free end of the clutch arm 154, and the other end side extension portion (the right end portion in the illustrated embodiment) of the pedal shaft 152 are extrapolated so as not to rotate relative to each other. The left brake boss 156L and the right brake boss 156 externally attached to the pedal shaft 152 so as to be rotatable relative to the other end side of the left brake boss 156L. A left brake arm 157L supported by the left brake boss 156L, a left brake pedal 158L provided at a free end of the left brake arm 157L, and a right brake arm 157R supported by the right brake boss 156R. And a right brake pedal 158R provided at a free end of the right brake arm 157R.

The clutch boss 153 is operatively connected to the clutch device 2 via a clutch link mechanism (not shown).
A portion of the one end side extension portion of the pedal shaft 152 located outside the clutch boss 153 in the vehicle width direction is operated by a left brake mechanism (not shown) via a left brake link mechanism (not shown). It is connected.
The right brake boss 157R is operatively connected to a right brake mechanism (not shown) via a right brake link mechanism (not shown).

  As shown in FIGS. 4 and 5, the operation lever portion 130 is a throttle that is a governor operation member for operating the forward / reverse switching operation member 131 in the form of a lever and the electronic governor mechanism 701 of the engine 10. Lever 141, main transmission lever 160 that switches the gear position of main transmission 16, and sub-transmission lever 190 that switches the gear position of sub-transmission device 19 are included.

The throttle lever 141 is indirectly supported by the dashboard stay 100.
Specifically, as shown in FIG. 6, a throttle lever stay 140 is connected to the dashboard stay 100.
The throttle lever stay 140 includes a side plate 140a having a front end connected to the mounting plate 101 of the dashboard stay 100 and a rear end of the side plate 140a extending inward in the vehicle width direction. The rear plate 140b connected to the right support plate 101b is substantially L-shaped in plan view.

The throttle lever 141 has a base end portion 142 along the vehicle width direction, and a grip portion 143 extending substantially upward from the vehicle width direction outer end portion of the base end portion 142.
The base end 142 is supported at the inner end in the vehicle width direction by the side plate 140b of the throttle lever stay 140 so as to be rotatable about its axis.
The grip part 143 has an upper end extending to the vicinity of the steering wheel 114.
The operation amount of the throttle lever 141 is converted into an electric signal by an operating position detection mechanism 705 described later, and is transmitted to a control device 700 (FIG. 4) that controls the electronic governor mechanism 701. The electronic governor mechanism 701 is electrically connected to the control device 700 through an electric cord 704.

In the present embodiment, the electronic governor mechanism 701 is configured to be operated by a throttle pedal 330 in addition to the throttle lever 141. That is, the governor operating member in this embodiment includes the throttle lever 141 and the throttle pedal 330. The throttle lever 141 and the throttle pedal 330 are configured to be interlocked by a throttle operation link mechanism 300.
FIG. 7 is a schematic diagram of the throttle operation link mechanism 300 in the present embodiment. FIG. 8 is a sectional view taken along line VIII-VIII in FIG.

As shown in FIGS. 7 and 8, the throttle operation link mechanism 300 includes a lever-side operation member 301 that is provided at a base end portion 142 of the throttle lever 141 so as not to be relatively rotatable, and the base end of the throttle lever 141. And an actuating member 305 that is rotatable about an axis with respect to the portion 142.
Further, as shown in FIG. 8, the operating member 305 is provided with an operating position detecting mechanism 705 that electrically detects the position (operating angle) of the operating member 305. The operation position detection mechanism 705 is fixed so as not to move relative to the detection piece 706 (fixed to the operation member 305 in FIG. 8) following the movement of the operation member 305 and the side plate 140b. And a detection unit 707 that electrically detects the position of the piece 706.
The operating position of the operating member 305 detected by the operating position detection mechanism 705 is sent to the control device 700 as an electrical signal.

The lever-side operation member 301 includes a main body 302 that is not rotatable relative to the base end 142 of the throttle lever 141 on the outer side in the vehicle width direction from the side plate 140 a of the throttle lever stay 140. And an operating piece 303 extending inwardly in the vehicle width direction from the periphery beyond the side plate 140a.
The operating piece 303 is engaged with one side surface (a front end surface in the illustrated embodiment) of the operating member 305 disposed on the inner side in the vehicle width direction from the side plate 140a.

As shown well in FIG. 7, the throttle pedal 330 is supported so as to be rotatable about an axis along the vehicle width direction, and extends from the base end 331 to above the step portion 41. A rod portion 332, a pedal portion 333 provided at the distal end portion of the rod portion 332, a pedal side arm portion 334 which is relatively unrotatable at the base end portion, and one of the base end portion 331 around the axis line And a return spring 335 for urging to the side.
In the present embodiment, the return spring 335 has one end fixed below the step portion 41 and the other end connected to the pedal-side arm 334.
The pedal side link member 315 has a pedal side rod extending between the operating member 305 and the pedal side arm portion 334.

Further, as shown in FIG. 8, the throttle operation link mechanism 300 includes a friction member 320 between the side plate 140 a of the throttle lever stay 140 and the lever side operation member 301.
The friction member 320 causes the lever-side operation member 302 to have a sliding resistance that can hold the position of the throttle lever 141 against the biasing force of the return spring 335.

The throttle operation link mechanism 300 having such a configuration operates as follows.
As shown in FIG. 7, when the throttle pedal 330 is depressed from an initial position (for example, the lowest output position L) to an operation position (for example, the highest output position H) against the biasing force of the return spring 335, The actuating member 305 swings in the first direction R1 around the axis of the base end 142 (hereinafter referred to as lever rotation center R). This swing is detected by the position detection mechanism 705, and the position of the operating member 305 is sent to the control device 700 as an electrical signal. The control device 700 transmits a control signal via the electric cord 704, and moves the electronic governor mechanism 701 to an initial position (minimum) according to the detected amount of movement of the actuating member 305 except at the time of starting control to be described later. Normal control for shifting from the output state to the operating position (maximum output state) is performed.
The operation piece 303 of the lever side operation member 301 is located on the second direction side of the operation member 305 with respect to the lever rotation center R.
Therefore, when the throttle pedal 330 is depressed, the throttle lever 141 remains in the initial position (minimum output position L).

When the depressing operation on the throttle pedal 330 is released, the throttle spring 330 is returned from the operating position to the initial position by the return spring 335, and the operating member 305 swings around the lever rotation center R in the second direction R2. . This swing is detected by the position detection mechanism 705, and the position of the operating member 305 is sent to the control device 700 as an electrical signal. The control device 700 transmits a control signal via the electric cord 704 to return the electronic governor mechanism 701 to the initial position.
The operating piece 303 is located in a notch formed in the side plate 140a of the throttle lever stay 140, and the operating range of the operating piece 303 is defined by the notch. Accordingly, the actuating member 305 that swings around the lever rotation center R in the second direction R2 by the urging force of the return spring 335 moves in the second direction R2 around the lever rotation center R by contacting the actuating piece 303. Is stopped.

On the other hand, when the throttle lever 141 is swung from the initial position to the operation position, the actuating member 303 swings the actuating member 305 about the lever rotation center R in the first direction R1. This swing is detected by the position detection mechanism 705, and the position of the operating member 305 is sent to the control device 700 as an electrical signal. The control device 700 transmits a control signal via the electric cord 704 to shift the electronic governor mechanism 701 from the initial position to the operation position.
At this time, the throttle pedal 330 moves from the initial position to the operating position via the pedal side link member 315 against the urging force of the return spring 335. Accordingly, the throttle lever 141 tends to be returned to the initial position by the return spring 335. As described above, the friction between the side plate 140a of the throttle lever stay 140 and the lever side operation member 301 is caused by the friction. A member 320 is provided.
Accordingly, the throttle lever 141 is held at the operating position by the friction member 320, and the control signal is continuously transmitted.

Such a throttle operation mechanism 300 has the following effects.
That is, in the normal control which will be described later, when the electronic governor mechanism 701 is to be temporarily positioned at the operation position (for example, the high output state of the engine 10), the throttle pedal 330 is depressed to operate the throttle. The electronic governor mechanism 701 can be positioned at the operation position only when the pedal 330 is depressed.
On the other hand, when the electronic governor mechanism 701 is to be continuously positioned at the operation position, the throttle lever 141 is moved to the initial position against the sliding resistance of the friction member 320 and the biasing force of the return spring 335. By shifting from the operating position to the operating position, a continuous control signal is transmitted from the control device 700 even after the operating force to the throttle lever 141 is released, and the electronic governor mechanism 701 can be held at the operating position.

Here, as shown in FIG. 4, the travel control mechanism in the present embodiment includes a shift speed detection sensor 702 that detects the shift speed of the auxiliary transmission 19 that is a multi-speed transmission and a speed sensor that detects the travel speed of the tractor 1. 703.
The control device 700 performs the normal control when the vehicle is started by engaging the clutch device 2 from a vehicle stop state in a state where the auxiliary transmission device 19 is engaged at a predetermined gear position or more. Instead, start control is performed to force the electronic governor mechanism 701 to the minimum output state regardless of the manual operation of the governor operating member (the throttle pedal 330 and / or the throttle lever 141).
FIG. 9 shows a control flow in the travel control mechanism of the present embodiment.

The travel control mechanism performs the normal control except during the start control (step S11).
Here, when it is detected by the speed sensor 703 that the tractor 1 has stopped (Yes in step S12), the control device 700 determines that the shift stage of the auxiliary transmission 19 detected by the shift stage detection sensor 702 is It is determined whether or not the engagement is greater than a predetermined shift speed (step S13). For example, when the predetermined gear position in the sub-transmission device 19 is set to the second speed (when the start-up control is performed when the gear position of the sub-transmission device 19 is engaged in a position other than the lowest speed stage), the gear position detection sensor 702 is used. When the detected gear position of the auxiliary transmission 19 is engaged with any of the second speed, the third speed, and the fourth speed (Yes in step S13), the control device 700 shifts from the normal control to the start control. (Step S14).

In the starting control, the electronic governor mechanism 701 is forcibly held at the minimum output state regardless of the manual operation positions of the throttle pedal 330 and the throttle lever 141. As a result, when the clutch device 2 is engaged and the tractor 1 is started (Yes in step S15), the tractor 1 starts (starts) with the engine output held at the minimum output.
If the gear position is re-changed before the tractor 1 is started and reengaged below a predetermined gear position (for example, the first speed) (No in step S15 and No in step S13), start control is executed. Normal control is performed.

After the tractor 1 is started by the start control, the control device 700 maintains the start control until the throttle pedal 330 and the throttle lever 141 are manually operated to the lowest output position L (step S16).
In other words, after the tractor 1 is started by the start control, when the throttle pedal 330 and the throttle lever 141 are manually operated so as to be positioned at the lowest output position L (Yes in step S16), the control device 700 is started from the start control. Shifting to control, the engine output is controlled to be changeable according to the operation state of the throttle pedal 330 and the throttle lever 141.

As described above, in the travel control mechanism of the present embodiment, when the shift stage of the auxiliary transmission 19 is greater than or equal to the predetermined shift stage when the tractor 1 is started, the governor operation member (the throttle pedal 330 and the pedestal 1). Regardless of the operation state of the throttle lever 141), since the electronic governor mechanism 701 is controlled by the control device 700 so that the engine output becomes the lowest, the sudden start of the tractor 1 can be effectively prevented, and the vehicle posture can be changed. It can be kept stable.
In addition, since the start control is canceled by positioning the governor operating members (the throttle pedal 330 and the throttle lever 141) at the minimum output position L, the start control with the engine output being restricted is changed to the normal control with the restriction being released. During the transition, a sudden change in the vehicle speed can be prevented, and the vehicle posture during the transition can be kept stable.

  In the present embodiment, the multi-stage transmission detected by the shift stage detection sensor 702 is only the sub-transmission apparatus 19. However, the present invention is not limited to this. For example, the shift stage of the main transmission 16 and the sub-transmission apparatus 19 is detected, and the control device 700 is controlled to start unless the gears of the main transmission 16 and the sub-transmission 19 are both 1st speed (minimum speed) in step S13. It may be done. Further, the gear position of the high / low speed switching device 13 may be detected and incorporated in the conditions of the start control.

  In the first embodiment, the electronic governor mechanism 701 is used as a mechanism for changing the output of the engine 10, but the present invention is not limited to this, and the throttle pedal 330 and the throttle lever 141, which are the governor operating members, and the throttle operation link mechanism are used. The governor mechanism 11 that is operatively connected via 300 may be used. This will be described below.

  In FIG. 10, the block diagram of the traveling control mechanism which concerns on 2nd Embodiment of this invention is shown. FIG. 11 is a schematic diagram of a throttle operation link mechanism 300 in the travel control mechanism according to the second embodiment of the present invention. FIG. 12 is a cross-sectional view taken along line XII-XII in FIG. In addition, the same code | symbol is attached | subjected about the structure similar to the said 1st Embodiment, and description is abbreviate | omitted.

As shown in FIGS. 11 and 12, the throttle operation link mechanism 300 includes a governor side link member 310 that operatively connects the operation member 305 and the governor mechanism 11.
The governor side link member 310 has a governor side rod extending between the actuating member 305 and the governor 11.

The throttle operation link mechanism 300 having such a configuration operates as follows.
As shown in FIG. 11, when the throttle pedal 330 is depressed from an initial position (for example, low output position L) to an operation position (for example, high output position H) against the biasing force of the return spring 335, The actuating member 305 swings in the first direction R1 around the axis of the base end 142 (hereinafter referred to as lever rotation center R), whereby the governor mechanism 11 is moved to the initial position (via the governor side link member 310). Transition from the low output state to the operating position (high output state).
The operation piece 303 of the lever side operation member 301 is located on the second direction side of the operation member 305 with respect to the lever rotation center R.
Therefore, when the throttle pedal 330 is depressed, the throttle lever 141 remains in the initial position (low output position L).

  When the depressing operation on the throttle pedal 330 is released, the throttle spring 330 is returned from the operating position to the initial position by the return spring 335, and the operating member 305 swings around the lever rotation center R in the second direction R2. Thereby, the governor mechanism 11 returns to the initial position via the governor side link member 310.

Here, as shown in FIG. 10, the travel control mechanism in the present embodiment includes a speed detection sensor 702 that detects the speed of the auxiliary transmission 19 that is a multi-speed transmission, and a speed that detects the travel speed of the tractor 1. A sensor 703, a governor actuator 801 that operates the governor mechanism 11 directly or indirectly, and a control device 800 that controls the governor actuator 801 based on a signal from the gear position detection sensor 702 are provided.
When the sub-transmission device 19 is engaged at a predetermined speed or higher and the clutch device 2 is engaged from the vehicle stop state to start the tractor 1, the control device 800 controls the governor. The actuator 801 is actuated to perform start control for forcing the governor mechanism 11 to the minimum output state.
FIG. 13 shows an example of a control flow in the travel control mechanism of the present embodiment.

The travel control mechanism performs normal control in which the governor actuator 801 does not intervene in the governor mechanism 11 except during start-up control (step S21).
Here, when it is detected by the speed sensor 703 that the tractor 1 has stopped (Yes in step S22), the control device 800 determines that the shift stage of the auxiliary transmission 19 detected by the shift stage detection sensor 702 is It is determined whether or not the engagement is greater than a predetermined shift speed (step S23). For example, when the predetermined gear position in the sub-transmission device 19 is set to the second speed (when the start-up control is performed when the gear position of the sub-transmission device 19 is engaged in a position other than the lowest speed stage), the gear position detection sensor 702 is used. When the detected gear position of the auxiliary transmission 19 is engaged with any of the second speed, the third speed, and the fourth speed (Yes in step S23), the control device 800 shifts from the normal control to the start control. (Step S24).

In the starting control, the governor actuator 801 is operated so that the governor mechanism 11 is forcibly set to a minimum output state. More specifically, for example, the governor actuator 801 moves to a position where the movement of the governor mechanism 11 is restricted in a state where the governor mechanism 11 is in the lowest output state. As a result, when the clutch device 2 is engaged and the tractor 1 is started (Yes in step S25), the tractor 1 starts (starts) with the engine output held at the minimum output.
If the gear position is re-changed before the tractor 1 is started and reengaged below a predetermined gear position (for example, the first speed) (No in step S25 and No in step S23), start control is executed. Normal control is performed.
Further, at the time of starting control, even if the throttle pedal 330 and the throttle lever 141 are artificially operated, the movement of the throttle pedal 330 and the throttle lever 141 from the lowest output position L is restricted by the intervention of the governor actuator 801. (Held at the lowest output position L).

After the tractor 1 is started by the start control, the control device 800 maintains the start control until the speed detection sensor 703 detects arrival at a predetermined vehicle speed (step S26).
That is, after the tractor 1 is started by the start control and reaches a predetermined vehicle speed preset by the speed detection sensor 703 (Yes in step S26), the control device 800 shifts from the start control to the normal control, and the governor The operation of the actuator 801 is released, and the governor mechanism 11 is operated according to the operation state of the throttle pedal 330 and the throttle lever 141, so that the engine output can be changed.

As described above, in the travel control mechanism of the present embodiment, when the speed of the auxiliary transmission 19 is greater than or equal to the predetermined speed when the tractor 1 is started, the governor actuator 801 is operated by the control device 800. Since the governor mechanism 11 is forcibly controlled so that the engine output becomes the minimum, the sudden start of the tractor 1 can be effectively prevented, and the vehicle posture can be kept stable.
In addition, after the tractor 1 is started, the start control is canceled when the predetermined speed is reached, so that when the start control is canceled, the vehicle output is rapidly changed immediately after starting or when the engine output is changed at a low vehicle speed. Can be prevented, and the vehicle posture at the time of transition can be kept stable.

Further, in the travel control mechanism in the present embodiment, as shown in FIG. 10, by providing a timer 802 capable of measuring the travel time from the vehicle stop state, the elapse of a predetermined time after the start of travel is started. It is also possible to set as a control release condition.
FIG. 14 shows another example of the control flow in the travel control mechanism of the present embodiment.
The steps up to the start of the tractor 1 by the start control (steps S31 to S35) are the same as the steps S21 to S25 in FIG.

  As the tractor 1 is started by the start control, the control device 800 starts measurement by the timer 802 (step S36).

After the tractor 1 is started by the start control (that is, after measurement by the timer 802 is started), the control device 800 maintains the start control until a predetermined time set in advance by the timer 802 elapses. (Step S37).
That is, after the tractor 1 is started by the start control, when the predetermined time preset by the timer 802 is reached (Yes in step S37), the control device 800 resets the measurement time (step S38) and starts. The control shifts from normal control to normal control, the operation of the governor actuator 801 is released, the governor mechanism 11 is operated according to the operation state of the throttle pedal 330 and the throttle lever 141, and the engine output can be changed.

  Thus, even if the start control is canceled after a lapse of a predetermined time after the tractor 1 is started, when the start control is released, the vehicle output is suddenly changed immediately after starting or when the engine output is changed at a low vehicle speed. Change can be prevented, and the vehicle posture at the time of transition can be kept stable.

  The embodiment according to the present invention has been described above, but the present invention is not limited to the above embodiment, and various improvements, changes, and modifications can be made without departing from the spirit of the present invention.

FIG. 1 is a left side view of a tractor to which a traveling control mechanism according to a first embodiment of the present invention is applied. FIG. 2 is a right side view of the tractor to which the traveling control mechanism according to the first embodiment of the present invention is applied. FIG. 3 is a view showing a transmission mechanism of the tractor to which the traveling control mechanism according to the first embodiment of the present invention is applied. FIG. 4 is a configuration diagram of the travel control mechanism in the present embodiment. FIG. 5 is a perspective view of the engine unit viewed from the left rear. FIG. 6 is a perspective view of the engine unit and the transmission unit as viewed from the right rear. FIG. 7 is a schematic diagram of a throttle operation link mechanism in the present embodiment. 8 is a sectional view taken along line VIII-VIII in FIG. FIG. 9 is a control flow in the travel control mechanism of the present embodiment. FIG. 10 is a configuration diagram of a travel control mechanism according to the second embodiment of the present invention. FIG. 11 is a schematic diagram of a throttle operation link mechanism in the travel control mechanism according to the second embodiment of the present invention. 12 is a cross-sectional view taken along line XII-XII in FIG. FIG. 13 is an example of a control flow in the travel control mechanism of the present embodiment. FIG. 14 is another example of the control flow in the travel control mechanism of this embodiment.

Explanation of symbols

1 Tractor (work vehicle)
2 Clutch device 10 Engine 11 Governor mechanism 19 Subtransmission (multi-stage transmission)
141 Throttle lever (governor operation member)
300 Operation link mechanism 330 Throttle pedal (governor operation member)
700,800 Control device 701 Electronic governor mechanism 702 Shift speed detection sensor 801 Governor actuator

Claims (4)

An engine having an electronic governor mechanism, a governor operating member for artificially operating the electronic governor mechanism, a control device for performing normal control for operating the electronic governor mechanism in response to an artificial operation to the governor operating member, and A travel control mechanism applied to a work vehicle having a clutch device and a multi-stage transmission device inserted in a travel system transmission system path from an engine to a drive wheel,
A shift speed detection sensor for detecting a shift speed of the multi-speed transmission,
When the vehicle is started by engaging the clutch device from a vehicle stop state in a state where the multi-stage transmission is engaged at a predetermined speed or more, the control device replaces the normal control, A travel control mechanism for performing start control for forcibly setting the electronic governor mechanism to a minimum output state regardless of a manual operation on a governor operation member.   The travel control mechanism according to claim 1, wherein the control device shifts to the normal control when the governor operating member is positioned at a minimum output position after the start control is performed. An engine having a governor mechanism, a governor operating member for artificially operating the governor mechanism, an operation link mechanism for operatively connecting the governor operating member and the governor mechanism, and a traveling system transmission system path from the engine to a drive wheel A travel control mechanism that is applied to a work vehicle including a clutch device and a multi-stage transmission that are interposed in the vehicle,
A shift speed detection sensor for detecting a shift speed of the multi-speed transmission, a governor actuator for operating the governor mechanism directly or indirectly, and a control device for controlling the governor actuator based on a signal from the shift speed detection sensor And
The control device operates the governor actuator when starting the vehicle by engaging the clutch device from a vehicle stop state in a state where the multi-stage transmission is engaged at a predetermined speed or more. A travel control mechanism for performing start control for forcibly setting a governor mechanism to a minimum output state.   The control device enables the manual operation of the governor operating member by shifting the governor actuator to an initial state after elapse of a predetermined time set in advance or after reaching a predetermined vehicle speed set in advance. The travel control mechanism according to claim 3, wherein:

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