JP2011011675A - Traveling work vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the steerability on a downhill slope in a traveling work vehicle in which an engine 18 as a traveling power source is mounted on a traveling frame 4 supported by wheels 2, 3, and an automatic clutch mechanism 20 which is changed to the power transmission ON from the power transmission OFF when the engine speed is increased from the idling engine speed to the predetermined value by the step-in operation of an accelerator pedal 23 is provided in the middle of a power transmission path from the engine to the wheels.SOLUTION: An engine brake mechanism 37 for keeping an accelerator pedal 23 at the position capable of obtaining the engine speed higher than the predetermined value when the step-in operation is released from that in the traveling state is provided on the accelerator pedal 23 in a traveling work vehicle, and the engine brake is applied when the vehicle travels on a downhill slope.

Description

  The present invention relates to a traveling work vehicle that is traveled by an engine mounted on a traveling frame and is used for various purposes such as transportation of luggage and various farming operations.

  Patent Document 1 as a prior art describes a traveling work vehicle configured to travel by mounting an engine on a traveling frame supported by wheels and driving and rotating the wheels by the engine. .

JP 2008-094179 A

  By the way, in the prior art traveling work vehicle, in the middle of the power transmission path from the engine to the wheel, the engine speed is set to a predetermined value from the idle speed by depressing the accelerator pedal for the engine. An automatic clutch mechanism is provided that switches from power transmission OFF to power transmission ON when the rotational speed increases.

  According to this configuration, it is possible to start the traveling work vehicle from a stopped state and to obtain an arbitrary traveling speed after starting by performing a stepping operation on the accelerator pedal. It has the advantage of being able to.

  However, on the other hand, when the traveling work vehicle approaches a downhill slope, by releasing the depression operation of the accelerator pedal, the engine speed decreases to the idle speed and the automatic clutch mechanism turns off the power transmission. As a result, the engine speed is not increased and the traveling speed is increased. Therefore, the driver is required to control the speed increase every time the vehicle approaches a downhill road. The driver has to depress the brake pedal against the engine, and it is not only troublesome for the driver who expects the same engine brake as an ordinary car, but also the speed control and control is unstable. , Damage to the brake mechanism of the wheel due to deterioration of brake oil due to frequent brake operation and premature wear of brake pads There is a problem in that it is large.

  An object of the present invention is to provide a traveling work vehicle that solves these problems.

In order to achieve this technical problem, claim 1
“An engine as a driving power source is mounted on a driving frame supported so as to be able to run on wheels, and the engine speed is idled by depressing the accelerator pedal in the middle of the power transmission path from this engine to the wheels. In a traveling work vehicle provided with an automatic clutch mechanism that switches from power transmission OFF to power transmission ON when the rotational speed increases from a rotational speed to a predetermined rotational speed,
The accelerator pedal has an engine brake mechanism configured to hold the accelerator pedal at a position where an engine speed higher than the predetermined speed can be obtained when the depression operation is released from the running state. Is provided. "
It is characterized by that.

Claim 2
“In the first aspect of the present invention, the engine brake mechanism is configured to release the holding of the accelerator pedal at a predetermined rotational speed in conjunction with the depression of the brake pedal with respect to the wheel. "
It is characterized by that.

Claim 3
“In the second aspect of the present invention, the engine brake mechanism includes a cam that holds the accelerator pedal at a predetermined rotational speed, and the cam is operated by the cam in response to a depressing operation of the brake pedal. It is configured to release the accelerator pedal. "
It is characterized by that.

  In the configuration of claim 1, when the depression operation of the accelerator pedal is released from the state where the depression operation is performed so that the traveling work vehicle travels at an appropriate speed, the accelerator pedal is set in the automatic clutch mechanism by the engine brake mechanism. It is held at a position where an engine speed higher than the engine speed can be obtained.

  As a result, the automatic clutch mechanism maintains the state in which the power transmission is ON and the wheel and the engine are connected to each other, so that the engine brake can be operated in conjunction with the release of the stepping operation on the accelerator pedal.

  Therefore, according to the first aspect of the present invention, the speed increase on the downhill road, which is a harmful effect of adopting the automatic clutch mechanism, can be reliably suppressed by operating the engine brake as described above. Therefore, it is possible to reduce the frequency of the stepping operation, improve the safety and driving maneuverability during driving, and improve the durability of the wheel brake mechanism.

  According to the second aspect of the present invention, since the engine brake by the accelerator pedal can be released by depressing the brake pedal, the driving maneuverability can be further improved.

  Furthermore, according to the third aspect of the present invention, it is possible to achieve an extremely simple mechanism using a cam to apply the engine brake and to release the engine brake.

1 is a side view showing a multipurpose transport vehicle according to an embodiment of the present invention. It is a partially cutaway top view of the transport vehicle. It is a perspective view when the said transport vehicle is seen from diagonally upward from the front. It is a principal part enlarged view of FIG. FIG. 5 is a VV sectional view of FIG. 4. It is a vertical front view of the continuously variable transmission mechanism provided with the automatic clutch. It is a figure which shows the engine brake mechanism with respect to an accelerator pedal. It is VIII-VIII sectional view taken on the line of FIG.

  Hereinafter, drawings (FIGS. 1 to 8) when an embodiment of the present invention is applied to a multipurpose transport vehicle as a traveling work vehicle will be described.

    The multi-purpose transport vehicle 1 in this embodiment has a traveling frame 4 supported by a pair of left and right front wheels 2 and a pair of left and right rear wheels 3. The traveling frame 4 includes both the front wheels 2 and both the front wheels 2. A driving cabin 5 is provided at a position between the rear wheel 3 and a loading platform 6 for placing an object to be transported at a position behind the driving cabin 5.

  As shown in FIGS. 1 to 3, the driving cabin 5 is configured in an enclosure frame shape in any of a side view, a front view, and a plan view. An assistant seat 8 is provided side by side, and steering is performed by simultaneously rotating the front wheels 2 in the left-right direction in front of the driver seat 7 by a steering mechanism (not shown). A round steering handle 9 is provided.

  The both seats 7 and 8 are positioned appropriately in front of the rear membrane plate 10 constituting the rear surface of the driving cabin 5 by an appropriate dimension L. In the middle, the space portion 11 is formed such that the left and right sides of the space portion 11 are open to the left and right sides of the driving cabin 5.

  In this case, the backrest portion 7 a of the driver seat 7 and the backrest portion 8 a of the assistant seat 8 overlap above the space portion 11. In addition, these backrest parts 7a and 8a can be tilted forward and rotated.

  In addition, on the outer side surface (left side surface) of the driver's seat 7, a hip-guard door stopper 12 configured in a downward U-shape is provided on the outer side surface (right side surface) of the assistant seat 8. Each part is provided with a door guard 13 that also serves as a hip guard and has a downward U-shape.

  Furthermore, a door 14 configured to be openable and closable outwardly is provided on the left side portion of the space portion 11, and a door 15 configured to be openable and closable outwardly is provided on the right side portion of the space portion 11. By opening or closing one or both of these doors 14 and 15, various working tools such as bags or various repair tools, work clothes, etc. are put in the space 11 It is configured to be able to keep.

  The traveling frame 4 includes a pair of left and right upper frames 16 extending rearward and a pair of left and right lower frames 17 extending rearward in the rear portion of the driving cabin 5.

  Between the lower frames 17 of the upper and lower frames 16 and 17, an engine 18 as a power source for traveling and a rear wheel gear case 19 are arranged. A case 19 is provided so as to be positioned on the rear side, and the power of the engine 18 is applied to the rear wheel via a continuously variable transmission mechanism 21 such as a belt type equipped with an automatic clutch 20 such as a centrifugal type. The rear wheel 3 is driven and rotated by the rear wheel gear case 13 so that the transport vehicle 1 moves forward or backward.

  A brake pedal 22 for each of the wheels 2 and 3 and an accelerator pedal for adjusting and controlling the number of revolutions of the engine 18 are provided on a portion of the floor surface of the driving cabin 5 in front of the driver seat 7. 23 are arranged side by side.

  As is well known in the art, when the engine 18 has a low rotational speed, the automatic clutch 20 is in a state in which the power transmission to the subsequent engine is OFF. However, when the accelerator pedal 23 is depressed, When the rotational speed of the engine 18 exceeds a predetermined rotational speed N1, the power transmission is turned on.

  That is, when the accelerator pedal 23 is not depressed, the transport vehicle 1 does not travel forward because the rotational speed of the engine 18 is low and the automatic clutch 20 is turned off.

  When the rotational speed of the engine 18 exceeds a predetermined rotational speed (N1) by depressing the accelerator pedal 23, the automatic clutch 20 is turned on, and the transport vehicle 1 starts traveling forward. .

  As is well known in the art, the belt-type continuously variable transmission mechanism 21 automatically changes the rotational speed of both rear wheels 3 relative to the rotational speed of the engine 18 in proportion to the rotational speed of the engine 18. This is a configuration in which a shift operation is automatically performed so as to increase the speed.

  That is, the automatic clutch 20 and the continuously variable transmission mechanism 21 are specifically configured as shown in FIG.

  That is, the output shaft 18a of the engine 18 is provided with a main pulley 21a composed of a fixed pulley piece 21a 'that does not slide in the axial direction and a movable pulley piece 21a "that freely slides in the axial direction. The pulley piece 21a ″ is urged by the spring 21b in a direction away from the fixed pulley piece 21a ′, while the input shaft 19a to the rear wheel gear case 19 has a fixed pulley piece 21c ′ that does not slide in the axial direction. , A driven pulley 21c composed of a movable pulley piece 21c ″ that freely slides in the axial direction is provided, and the movable pulley piece 21c ″ is urged to be pressed against the fixed pulley piece 21c ′ by a spring 21d. Thus, an endless belt 21e is wound between the main pulley 21a and the driven pulley 21c.

  The output shaft 18a of the engine 18 is provided with a governor mechanism 20a between the main pulley 21a and the movable pulley piece 21a ″. When the engine 18 has a slow rotation speed in the idle ring region, the main pulley Since the movable pulley piece 21a ″ in 21a is separated from the fixed pulley piece 21a ′ by the spring 21b, the power transmission to the rear wheel gear case 19 is turned off, but the rotational speed of the engine 18 is When the predetermined number of rotations (N1) is reached by the depression operation of the accelerator pedal 23, the movable pulley piece 21a "moves forward against the spring 21b toward the fixed pulley piece 21a ', and the endless belt 21e therebetween is moved. Therefore, the power transmission to the rear wheel gear case 19 is turned on.

  When the rotational speed of the engine 18 becomes higher by the depression operation of the accelerator pedal 23, the rotational speed in the rear wheel gear case 19 and hence the rotational speed in the rear wheel 3 are proportional to the rotational speed in the engine 18. Thus, the gear shift operation is automatically performed so as to automatically increase the speed.

  On the other hand, a lifting roller 24 is rotatably provided on the upper surface of the rear end portion of the upper frame 16 among the upper and lower frames 16, 17, and the loading platform 6 can be freely moved in the front-rear direction. It is supported so that it can move to.

  In this case, the elevating roller 24 is fitted into a grooved rail 25 provided on the lower surface of the cargo bed 6 so as to extend in the front-rear direction. The guide is guided so as to move only linearly.

  The upper surface of the upper frames 16 is provided with a supporting roller 26 that fits into the grooved rail 25 on the lower surface of the loading platform 6 so that the loading platform 6 is supported in a substantially horizontal state. Yes.

  And between the rear ends of the lower frames 17, a rotatable elevating shaft 27 is mounted, and a lower end (base end) of the elevating link 28 is fixed to the elevating shaft 27, and the elevating link is fixed. A hydraulic cylinder in which the upper end of 28 is pivotally attached to a rear end portion of the lower surface of the loading platform 6 by a pin 29 and the elevating link 28 is provided between the elevating link 28 and the lower frame 17. At 30, it is configured to be driven and rotated in the front-rear direction.

  The loading platform 6 is tilted so that the rear end thereof is lowered from the horizontal position with the lifting roller 24 as a fulcrum by rotating the lifting link 28 backward by the hydraulic cylinder 30. As indicated by the chain line, the rear end of the load is lowered so as to approach the ground, so that the object to be loaded and unloaded from the load carrier 6 can be lowered in height from the ground. It can be done easily.

  Further, by rotating the elevating link 28 in the reverse direction, that is, in the forward direction by the hydraulic cylinder 30, the loading platform 6 does not move up, so that the elevating roller 24 is used as a fulcrum to restore the original state from the rear inclined state. And return to the original position supported by the elevating roller 24 and the supporting roller 26.

  Further, as shown in FIG. 4, the upper frame 16 is provided with a lock mechanism 31 configured to be switchable between a state in which the loading platform 6 is locked so as not to move and a state in which the lock is released.

  The lock mechanism 31 includes a flange 33 pivotally attached to the upper frame 16 by a pin 32, and an engagement piece 34 fixed to the lower surface of the cargo bed 6, and the flange 33 has a lower end thereof. A spring 35 provided between the upper frame 16 and the upper frame 16 is always engaged with the engagement piece 34, that is, in a locked state. The locked state is released by rotating against a spring 35 via a wire 36 by operating a provided lever (not shown).

  As shown in FIGS. 7 and 8, an engine brake mechanism 37 is provided for the brake pedal 22 and the accelerator pedal 23 in the driving cabin 4.

  The accelerator pedal 23 is linked to an accelerator lever 18b of the engine 18 via a wire 38, so that the engine 18 is idle when the accelerator pedal 23 is not depressed as shown by a one-dot chain line. When the accelerator pedal 23 is depressed to the position indicated by the solid line, the engine 18 turns to a predetermined speed (N1) at which the automatic clutch 20 turns on power transmission. When the accelerator pedal 23 is further depressed as shown by a two-dot chain line beyond the position indicated by the solid line, the engine 18 is configured to further increase the rotational speed, and the accelerator lever 18b or the accelerator pedal is configured. 23 is provided with a spring 39 for biasing it to the idle rotation position.

  The engine brake mechanism 37 includes a single rotary shaft 40 that is rotatably supported. A cam 41 is fixed to the rotary shaft 40, while a rod rod 42 is attached to the accelerator pedal 23. It is provided so as to extend toward the cam 41.

  The rod rod 42 contacts the cam 41 when the accelerator pedal 23 is in the depressed position shown by a solid line in FIG. 7, and maintains the engine speed at which the automatic clutch 20 turns on power transmission. The cam 41 is configured so that the spring 43 holds the position where the rod rod 42 contacts the cam 41, that is, the cam 41 contacts the stopper 46. Yes.

  When the rotary shaft 40 is provided with a release lever 44, the brake pedal 22 is provided with an engagement piece 45 projecting toward the release lever 44, and when the brake pedal 22 is depressed, When the engagement piece 45 contacts the release lever 44, the cam 41 is rotated to release the state in which the rod rod 42 contacts the cam 41.

  In this configuration, when the stepping operation of the accelerator pedal 23 is released from the state where the stepping operation (position indicated by a two-dot chain line) is performed so that the traveling work vehicle travels at an appropriate speed, the accelerator pedal 23 is indicated by a solid line. When returning to the indicated position, the rod rod 42 in the engine brake mechanism 37 contacts the cam 41 and is held at a position where an engine speed higher than the predetermined speed in the automatic clutch mechanism 20 can be obtained. The

  As a result, the automatic crack mechanism 20 keeps the power transmission ON and maintains the state in which the rear wheel 3 and the engine 18 are connected. Therefore, in conjunction with the release of the depression operation on the accelerator pedal 23, the engine brake is applied. Can work.

  Next, when the brake pedal 22 is depressed from the brake OFF state to the brake ON state in this state, the cam 41 rotates in conjunction with this operation, so that the accelerator pedal 23 is released from being held at the engine speed. Therefore, thereafter, the accelerator pedal 23 can be set to the idle position.

  In another embodiment of the present invention, the vehicle body frame 4 is provided with an inclination sensor that detects its forward / backward movement (pitching movement). When this inclination sensor detects a downhill, the brake pedal 22 is then depressed. The engine brake can be maintained in a working state until it is operated.

  In the case of this other embodiment, when the accelerator pedal 23 is in a position where the engine speed is kept constant, when the brake pedal 22 is depressed, and the tilt sensor detects a downhill, the accelerator pedal 23 is The engine brake is surely applied on the downhill by being configured to maintain the minimum engine speed (N1) at which the power transmission from the continuously variable transmission mechanism 21 to the rear wheel gear case 10 is ON. It is possible to improve driving maneuverability.

  In the above-described embodiment, the loading / unloading movement of the loading platform 6 while tilting backward is performed by driving and rotating the lifting link 28 in the front-rear direction. However, the present invention is not limited thereto. First, instead of the forward / backward rotation of the lifting / lowering link 28, the lifting / lowering movement while tilting backward in the loading platform 6 is driven by rotating either one or both of the lifting / lowering rollers 24 in the forward / reverse direction. Can be done.

  In the above embodiment, the rear wheel 3 is driven and rotated by the engine 18. However, the present invention is not limited to this, and the front wheel 2 is driven and rotated by the engine 18. Needless to say, the present invention can also be applied to the case where both the front wheel 2 and the rear wheel 3 are driven to rotate.

DESCRIPTION OF SYMBOLS 1 Carrier vehicle 2 Front wheel 3 Rear wheel 4 Traveling frame 5 Driving cabin 7, 8 Seat 6 Loading platform 11 Space part 16 Upper frame 17 Lower frame 18 Engine 20 Automatic clutch mechanism 21 Continuously variable transmission mechanism 22 Brake pedal 23 Accelerator pedal 24 Lifting roller 26 Supporting roller 27 Elevating shaft 28 Elevating link 30 Hydraulic cylinder 37 Engine brake mechanism 40 Rotating shaft 41 Cam

Claims (3)

An engine as a traveling power source is mounted on a traveling frame supported by wheels so that it can run freely. The engine speed is idled by depressing the accelerator pedal in the middle of the power transmission path from the engine to the wheels. In a traveling work vehicle provided with an automatic clutch mechanism that switches from power transmission OFF to power transmission ON when the rotation speed increases from a certain number to a predetermined number of revolutions.
The accelerator pedal has an engine brake mechanism configured to hold the accelerator pedal at a position where an engine speed higher than the predetermined speed can be obtained when the depression operation is released from the running state. A traveling work vehicle characterized by being provided.   The engine brake mechanism according to claim 1, wherein the engine brake mechanism is configured to release the holding of the accelerator pedal at a predetermined rotational speed in conjunction with a depressing operation of the brake pedal with respect to the wheel. A featured traveling work vehicle.   2. The engine brake mechanism according to claim 1, wherein the engine brake mechanism includes a cam that holds the accelerator pedal at a position of a predetermined number of rotations, and the cam is linked to an operation of depressing the brake pedal, and the accelerator pedal is operated by the cam. A traveling work vehicle configured to release the holding of the pedal.

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