JP2007331425A - Working vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a working vehicle easy to operate for creeping speed forward/reverse travel even when an operator takes either forward-looking or backward-looking seat. <P>SOLUTION: On condition that a sub transmission device 83 is at the lowest-speed position and a main transmission device 82 is at a first-speed position when a working machine working sensing means 25 senses that the vehicle is working, using a back hoe 9 mountable on the rear part of a machine body 2 (which may include that an engine speed is a predetermined speed or lower), a slight speed switch 94 is turned on which is located where the worker seated on either the forward-looking seat 8 or the backward-looking seat 8' can easily operate it, and then a forward/reverse travel change-over clutch 81 is actuated to permit the forward/reverse travel of the machine body 2 at a slow-travel speed. Thus, the machine body can be safely moved during back hoe working. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a work vehicle such as a tractor provided with a front-side external work machine and a back-side external work machine.

Conventionally, forward / reverse switching of a work vehicle such as an agricultural tractor is performed by operating a forward / reverse switching lever provided in a steering wheel of a forward / reverse switching device in a constantly meshing gear transmission.
However, some work performed using a work vehicle such as an agricultural tractor may require forward and backward movement at a slow speed. At this time, in the case of the constantly meshing gear transmission, the clutch pedal must be kept in a half-clutch state to move back and forth at a slow speed.
Japanese Laid-Open Patent Publication No. 2003-2258 discloses a work vehicle equipped with a transmission that can improve the forward / backward movement by operating the forward / reverse switching lever.
Japanese Patent Laid-Open No. 2003-2258

The invention described in Patent Document 1 can move forward and backward at a very low speed by operating the forward / reverse switching lever, so that the maneuverability of the vehicle is improved as compared to the previous vehicle, but the forward / reverse switching provided under the steering wheel. Since the operation is performed by operating the lever, the forward / reverse switching lever cannot be touched when the operator is seated in the backward seat. For this reason, the vehicle cannot be steered forward and backward at a slow speed.
SUMMARY OF THE INVENTION An object of the present invention is to provide a work vehicle that can be easily and safely operated to move the vehicle back and forth at a very low speed even when seated on a rear-facing seat in order to control a back working machine.

The problems of the present invention are solved by the following means.
The invention according to claim 1 is a rear work machine (9) that can be freely mounted on the rear part of the machine body (2), and a main transmission (82) that switches the traveling speed of the machine body (2) to one of a plurality of shift positions. And a forward / reverse switching clutch (81) for switching the traveling direction of the sub-transmission (83) and the fuselage (2) for switching to any one of a plurality of shift positions with respect to the shift position selected by the main transmission (82). ), A shift position detecting means (26) capable of detecting the shift position selected by the main transmission (82) and the sub-transmission (83), and the seat (8, 8 ′) forward or backward. In a work vehicle that travels by engine power having a cockpit that can be turned), a low-speed travel switch means (94) for switching operation of the forward / reverse switching clutch (81) is provided as a rear-facing seat (8 '). There is provided work machine work detection means (25) which is arranged on an operable machine body and senses that the work using the rear work machine (9) is in progress, and there is detection of the work machine work detection means (25). The low speed travel switch means (94) in a state where the shift position detecting means (26) detects that the auxiliary transmission (83) is at the predetermined low speed position and the main transmission (82) is at the predetermined low speed position. When there is an input, the work vehicle is provided with a control device (100) that enables the forward / reverse switching clutch (81) to operate to allow the airframe (2) to move forward or backward.

  According to a second aspect of the present invention, an engine speed detecting means (27) is provided, and the engine speed detecting means (27) detects that the engine speed is equal to or lower than a predetermined speed, and the work machine work detecting means. (25) senses that the rear work machine (9) is being used, and confirms that the auxiliary transmission (83) is at a predetermined low speed position and the main transmission (82) is at a predetermined low speed position. In the state detected by the shift position detecting means (26), when there is an input from the low speed travel switch means (94), the control device (100) operates the forward / reverse switching clutch (81) to operate the airframe (2). The work vehicle according to claim 1, wherein control is performed to enable forward or reverse travel.

  The invention according to claim 3 is a pair of left and right brake devices (88L, 88R) for braking the pair of left and right wheels (6b, 6b) in the forward direction of the airframe (2) and the pair of left and right brake devices (88L). , 88R) is provided with a pair of left and right brake control valves (90L, 90R). When the work machine work sensing means (25) senses that the work using the rear work machine (9) is in progress, the control device ( 100) is configured such that any one of the brake control valves (88L, 88R) can be operated independently by operating any one of the brake control valves (90L, 90R) by the input of the low-speed travel switch means (94). The work vehicle according to claim 1.

According to the first aspect of the present invention, when the rear working machine (9) such as a backhoe is working, the operator seated on the rear facing seat (8 ') can operate at a low speed traveling switch means (at an operable position). 94) is input, and when the shift position of the main transmission (82) is at a predetermined low speed position and the shift position of the auxiliary transmission (83) is at a predetermined low speed position, the airframe (2) is moved at the traveling speed. Since it can be moved, the operator can move forward and backward at a slow speed while operating the rear work machine (9) facing backwards with respect to the machine (2), so it is safe even when the machine (2) is not stopped The rear working machine (9) can be used for the work.
Even when the work is interrupted and the work place is moved, the aircraft can be moved forward and backward safely.

  According to the second aspect of the present invention, in addition to the effect of the first aspect of the invention, the airframe (2) can be slightly moved forward and backward when the engine speed is equal to or lower than the predetermined speed. is there.

  According to the invention described in claim 3, in addition to the effect of the invention described in claim 1, either the left or right brake device (2) is slightly moved while the vehicle body (2) is moving forward and backward slightly by the low-speed travel switch means (94). 88L, 88R) can be operated independently, so that the traveling direction of the airframe can be corrected and turned, and the working range using the rear working machine (9) is further expanded.

Embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a side view of a tractor according to an embodiment of the present invention. 2 shows a plan view of the transmission system in the transmission of the tractor of FIG. 1, FIG. 3 shows a plan view of the left rear axle portion, and FIG. 4 shows a left side view of the transmission system in the transmission. In this specification, the left and right directions in the direction of travel of the tractor are referred to as left and right, respectively, and the front and rear directions in the direction of travel are referred to as front and rear, respectively.

  The conventionally known tractor 1 transmits the rotational power of an engine (not shown) mounted on the airframe 2 to a main transmission 82 (FIG. 2) in the mission case 3. Further, the opening degree of the throttle valve of the engine changes in accordance with the amount of depression of an accelerator pedal (not shown) provided on the floor 5, and the rotational speed of the power shaft input to the transmission increases or decreases, so that the rear wheel 6b is moved. Drive. The front wheel 6a is rotated by the driving force of the rear wheel 6b.

  The transmission system shown in FIG. 2 includes a main clutch 80, a forward / reverse switching device 81 (81F, 81R), a main transmission device 82, and a subtransmission device 83 in the transmission case 3, and changes the rotation of the engine to drive shafts. 84 is transmitted to the rear wheel differential device 85 and the front wheel differential device 86 to drive the rear wheel 6b and the front wheel 6a.

Although detailed description is omitted in this embodiment, the gear shift mode of the main transmission 82 is changed by operating the main transmission lever 21 (see FIG. 11) to set one of the first to fourth gear positions. In addition, by changing the gear meshing mode of the sub-transmission device 83 by operating the sub-transmission lever 22, a total of three stages from the lowest speed to the medium speed stage and the high speed stage (or two stages of the lowest speed and the highest speed) are possible. The shift position can be set.
In the main transmission 82 and the sub-transmission 83, which gear position is engaged with each other can be detected by a well-known detection means for detecting each operation position of the main transmission lever 21 and the sub-transmission lever 22. .

  As shown in FIG. 3, the left and right rear axles 87 interlocking with the rear wheel 6b are respectively provided with brake devices 88L and 88R (only the left side is shown in FIG. 3), and brake arms 89L and 89R (shown in FIG. 3). It is configured to be braked by a swinging operation (only the left side is shown). As shown in FIG. 4, the brake arms 89L and 89R (only the left side is shown in FIG. 4) are provided on the braking side of the brake control valves 90L and 90R (see also FIG. 9) provided on the left and right outer surfaces of the mission case 3, respectively. Is switched to the braking side by the extension operation of the brake pistons 91L and 91R (see also FIG. 9) provided integrally with the box of the valves 90L and 90R. The non-braking side return is performed by an elastic return spring (not shown). Since the brake arms 89L and 89R are mechanically linked to a brake pedal (not shown), the left and right rear wheels 6b can be braked independently by pedal operation.

  Above the floor 5, a steering handle 7, a cockpit seat 8, a backhoe 9, a front loader 10, a clutch pedal (not shown), a pair of left and right brake pedals, a main transmission lever 21 and a sub transmission lever shown in FIG. 22 and a four-wheel drive lever 23 are provided. The steering handle 7 is supported by a handle post 12.

  The cockpit is provided with a forward seat 8 and a rear seat 8 '. The front loader 10 can be operated when seated on the forward seat 8, and the backhoe 9 can be operated when seated on the rear seat 8 ′. Note that the forward seat 8 and the backward seat 8 'may be configured to be capable of accommodating the backward seat 8' by being provided separately from each other in addition to the front-reverse type.

Next, an operation mechanism for the operation of the back hoe 9 of the tractor 1 (up and down movement of the arm part and up and down movement and bucket rotation, and arm rotation movement) and the operation of the front loader 10 (up and down movement and up and down movement) will be described with reference to FIG. .
The backhoe 9 is provided with a bucket 44 for discharging soil, the bucket 44 is connected to a first arm 45, and the second arm 46 is connected to the first arm 45. The bucket 44 can swing up and down by a bucket cylinder 48 around the rotation center 44a, the first arm 45 is raised and lowered by a first arm cylinder 49, and the second arm 46 is a second arm. The cylinder 50 moves up and down.

  Further, the bucket 17 of the front loader 10 is connected to the first boom 52 around the rotation center 17 a, and the second boom 53 is connected to the first boom 52. The bucket 17 can swing up and down by a bucket cylinder 55, and the second boom 53 is raised and lowered by the second boom cylinder 54.

  Further, at a connecting portion between the backhoe 9 and the rear wall of the tractor 1 main body, a pair of brackets 24 locked to a connecting member (not shown) provided on the body 2 of the tractor 1 and a pair of hydraulic cylinders (not shown), etc. , And the other end of the hydraulic cylinder is rotatably fixed to a support member 33 at the base of the backhoe 9.

  A pair of left and right outriggers 40 are connected to the bracket 24 so as to extend and contract in the vertical direction. A hydraulic cylinder is built in the outrigger 40, and the outrigger 40 is configured to be movable up and down. Stable operation is possible by operating the outrigger 40 on the ground during operation.

  Further, when the operator works while sitting on the rearward seat 8 'without lowering the outrigger 40, a braking force is applied to the tractor rear wheel 6b as described later. This is because it is preferable from the viewpoint of safety that the outrigger 40 is lowered to the ground when the backhoe 9 is operated while sitting on the rearward seat 8 '. However, when a light work is performed using the backhoe 9, there is no problem even if the work is performed without lowering the outrigger 40. Therefore, when working using the backhoe 9 without lowering the outrigger 40 to the ground, at least the rear wheel braking state can be set to avoid unexpected problems.

  Further, if the outrigger 40 is lowered to the ground, it is a heavy work when working with the backhoe 9, so that the normal operation with the driver sitting on the seat 8 'and stopping the vehicle is stopped. Be able to work.

  A forward / reverse switching lever 93 is provided on the side surface of the handle post 12 below the steering handle 7 of the steering section of the tractor 1 of this embodiment, and a low-speed traveling switch means (hereinafter referred to as a fine speed switch) is provided on the right fender 19R adjacent to the steering section. .) 94 is provided, and the hydraulic (forward / reverse) clutch 81F, 81R for forward / reverse switching can be switched by operating either the forward / reverse switching lever 93 or the slow speed switch 94.

  The slow switch 94 is a lever-like switch, and can be swung around a base (not shown) as schematically shown in FIG. 5. By swinging back and forth and right and left in the forward direction of the tractor 1, Forward, backward, left brake turn and right brake turn are possible. For example, in the left brake turning, the left brake device 88L is actuated to stop the rotation of the left rear wheel 6b, while the right rear wheel 6b rotates normally, so that the left brake turning is possible.

  In addition, tilting the slow switch 94 to the right diagonally forward allows a right turn while moving forward, tilting to the left diagonally forward allows a left turn while moving forward, tilting to the right diagonal rear allows a right turn while moving backward, If you tilt it to the left diagonally backward, you can turn left while moving backward.

  A fine speed switch 94 provided on the right fender 19R of the tractor 1 is a switch for moving the tractor 1 forward and backward during backhoe work, and this fine speed switch 94 is provided separately from the forward / reverse lever 93 provided on the handle post 12. It is a thing. Further, the input of the slow speed switch 94 and the input of the forward / reverse lever 93 are separately input to the control device 100 shown in FIG. 6, and the input of the slow speed switch 94 is accepted only when the tractor 1 is set to the low speed traveling lever. Further, when the seat is reversed (rearward), the input of the slow speed switch 94 is given priority over the input of the forward / reverse lever 93.

Further, the operation of the slow speed switch 94 is accepted only when the forward / reverse lever 93 is neutral, and the input of the forward / backward lever 93 is not accepted during the operation of the slow speed switch 94. The above control flow is shown in the flowchart of FIG.
As shown in this flow, the forward / backward movement is enabled by the slow switch 94 because the operator is seated and operated on the rear facing seat 8 'during the work using the backhoe 9 (hereinafter referred to as backhoe work) If the tractor 1 is moved forward and backward at high speed during this operation, an unexpected situation may occur, and it is sufficient to move the tractor 1 forward and backward slightly during backhoe work, and it is not necessary to move it at high speed. by.

  Further, when the tractor 1 is moved forward and backward using the fine speed switch 94, the tractor 1 is moved forward and backward more safely during the backhoe work by constantly blowing the buzzer at an early cycle and alerting the operator. May be.

  Further, in the tractor 1 of the present embodiment having the above-described configuration, when the backhoe work detection sensor 25 (FIG. 6) detects that the backhoe work is being performed, the tractor 1 is in the main speed change state with the fine speed switch 94 turned on. Is a main shift first speed / sub-shift low-speed detection sensor 26a (see FIG. 5) provided on the main shift lever 21 and the sub-shift lever 22 that the first speed and the sub-shift are running at the lowest speed. When 6) is detected, the tractor 1 is movable as shown in the flowchart of FIG. At this time, when the fine speed switch 94 is turned on, the engine speed sensor 27 detects that the main speed is the first speed or the sub speed is low, and the engine speed sensor 27 detects that the engine speed is equal to or less than a predetermined speed. It may be configured.

  These controls are performed so that the tractor 1 can be moved forward and backward so as not to impair the work efficiency on the condition that the operator is sitting on the seat 8 'facing backward and is working. Further, when the fine speed switch 94 is turned on, for example, when the main speed is not the first speed or the lowest speed of the sub speed, the alarm buzzer 28, a warning light, etc. are warned and the work of operating the fine speed switch 94 cannot be performed. To the operator.

  FIG. 9 shows a part of the hydraulic circuit of the tractor 1 of this embodiment. The brake pistons 91L and 91R for turning the rear wheel 6b are independent of the brake devices 88L and 88R for the left and right rear wheels 6b. For example, when the steering angle of the steering handle 7 exceeds a certain angle, the turning radius can be automatically reduced by braking the inner wheel side of the rear wheel 6b.

  Further, the tractor 1 of the present embodiment can brake the brake devices 88L and 88R independently by the left and right brake control valves 90L and 90R while the tractor 1 is traveling forward and backward while performing backhoe work. Yes, it can be steered in the left-right direction. The significance of performing such steering control is as follows.

  That is, when the operator sits on the rearward seat 8 ′ of the cockpit of the tractor 1 to perform the backhoe operation, the predetermined position cannot be reached only by moving the tractor 1 in the front-rear direction using the slow speed switch 94. In some cases, the steering direction can be adjusted by tilting the slow speed switch 94 in the left-right direction by a one-brake action (a brake is applied to the rear wheel 6b only on one side independently).

Thus, the following effects can be obtained by associating the left and right rear wheels 6b in the tractor 1 of this embodiment with the forward / reverse control while independently controlling the brakes.
First, when the tractor 1 is stopped, including during grooving work on the backhoe 9 in a field, etc., the outrigger 40 is grounded to stabilize the tractor 1 in order to prevent misalignment of the airframe in a normal state. In the case of work that does not take up (for example, shallow digging work), the time for grounding the outrigger 40 may be omitted. However, if the brake is not applied to the rear wheel 6b of the tractor 1 at this time, the work cannot be performed with the airframe stabilized even with a light load. Therefore, during the backhoe work, a light brake is applied to the tractor rear wheel 6b to stabilize the tractor 1 and enable a light load work.

However, the backhoe work is not only performed at a fixed position, but when a series of work is completed, the tractor 1 itself needs to be moved slightly to move to the next work.
Therefore, when the operator moves and changes the direction in the driving posture of the backhoe work (backward posture with respect to the main body of the tractor 1), the one-brake control and the front-rear control for braking the left and right rear wheels 6b and 6b independently. By associating the advance control, the one-brake can be applied to the rear wheel 6b by operating the fine speed switch 94, so that the direction of the tractor 1 can be changed. Since this change of direction does not require the steering handle 7 to be operated, the operator can quickly change the direction of the tractor 1 while keeping its rearward posture.

  Further, when the outrigger 40 is grounded and the body of the tractor 1 is floated, the wheels may idle due to the rotation of the forward / reverse clutches 81F and 81R, but the left and right rear wheels 6b are performed independently. By associating the brake control and the forward / reverse control, the brake can be applied to the rear wheel 6b during the backhoe work, so that the idling can be prevented.

Further, when the tractor 1 is moved forward and backward by the operation of the fine speed switch 94, the pressure increase control of the forward and backward clutches 81F and 81R is performed for 1 second without immediately increasing the pressure of the clutches 81F and 81R after the operation of the fine speed switch 94. An output delay in which the output is delayed by a certain degree may be provided. A control flow in this case is shown in FIG.
This control is intended especially for the safety of the operator who is seated in the rear-facing seat 8 'and performing the backhoe work. During this output delay, it is desirable to call attention with a horn or the like (a horn with a period as fast as possible).

  Further, as shown in the hydraulic circuit of FIG. 9, during the backhoe operation while the tractor 1 is stopped, the forward / reverse clutch control valve 92 and the forward / reverse clutches 81F and 81R for controlling the operation of the forward / reverse clutches 81F and 81R are provided. Preload lines 61a and 61b branched from connecting oil passages 60a and 60b are provided, and pressure oil can be supplied from the preload lines 61a and 61b to the left and right brake pistons 91L and 91R, respectively. The preload lines 61a and 61b are provided with a switching valve 62 and a check valve 65. The switching valve 62 supplies pressure oil from the preload lines 61a and 61b to the brake pistons 91L and 91R unless the electromagnetic proportional valve 70 is operated. The check valve 65 prevents pressure oil from flowing from the brake pistons 91L, 91R toward the forward / reverse clutches 81F, 81R.

  When the tractor 1 is stopped, no pressure oil is supplied to the forward / reverse clutches 81F and 81R. Therefore, when the mechanical relief valve 69 is opened by the pressure oil from the hydraulic pump 66, the pressure oil is supplied from the neutral oil passage of the forward / reverse clutch control valve 92. Is supplied to the preload lines 61a and 61b, the left and right brake pistons 91L and 91R are in a state where a light brake is applied. At this time, the switch 62 cannot be moved in the closing direction (right direction in the drawing) by the tension of the spring 62a of the switching valve 62. Therefore, even if the outrigger 40 is not grounded, the rear wheel 6b is braked by the left and right brake pistons 91L and 91R that are lightly braked even in the neutral state, so that the backhoe operation and the like can be stabilized.

When the electromagnetic proportional valve 70 of the mechanical relief valve 69 is turned on with the current value i while the tractor 1 is traveling, the pressure (Pi) applied to the piston 71 becomes a value proportional to the current value i, and the mechanical relief valve 69 Since the relief pressure is increased and the switching valve 62 is also operated, high pressure oil proportional to the relief pressure is supplied to the forward clutch 81F or the reverse clutch 81R. At this time, the forward clutch 81F or the reverse clutch 81R can adjust the clutch pressure from the half clutch state to the full pressure state according to the current value i.
At this time, relatively high pressure oil corresponding to the current value i of the electromagnetic proportional valve 70 of the mechanical relief valve 69 is supplied to the switching valve 62, the left brake piston 91L and / or the right brake piston 91R are turned off, and the rear wheel 6b The brake is released.
Further, when pressure oil is supplied to the steering hydraulic circuit 68 by the operation of the second hydraulic pump 67, the orbit roll and the power steering cylinder can be operated.

FIG. 11 shows the auxiliary transmission lever 22 and the four wheels so that the tractor 1 can be controlled not only when the operator is seated on the forward seat 8 of the cockpit but also when the operator is seated on the rear seat 8 ′. The perspective view at the time of arrange | positioning the drive lever 23 to the left fender 19L is shown.
Regardless of whether the seat 8 or 8 'is seated in the front or back direction, various operations using the tractor 1 can be performed by operating the auxiliary transmission lever 22 and the four-wheel drive lever 23, and the labor for changing the posture can be saved.

  The tractor of the present invention can be used as a machine for various works other than farm work.

It is a left view of the tractor of the Example of this invention. It is a top view of the transmission system in the transmission of the tractor of FIG. It is a top view of the rear axle part of the left side of the tractor of FIG. It is a left view of the transmission system in the transmission of the tractor of FIG. It is a figure explaining the function of the fine speed switch of the tractor of FIG. It is a control block diagram at the time of operation of the slow speed switch and the forward / reverse lever of the tractor of FIG. It is a control flow figure at the time of the slow speed switch and forward / reverse lever operation of the tractor of FIG. It is a control flow figure in the case of performing a light work using the backhoe of the tractor of FIG. FIG. 2 is a hydraulic circuit diagram for operating a forward / reverse clutch and a brake piston of the tractor of FIG. 1. FIG. 2 is a control flow diagram for delaying forward / reverse clutch output after operation of a slow speed switch of the tractor of FIG. 1. FIG. 2 is a perspective view showing an arrangement example of an auxiliary transmission lever and a four-wheel drive lever near the cockpit of the tractor of FIG. 1.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Tractor 2 Airframe 3 Mission case 5 Floor 6a Front wheel 6b Rear wheel 7 Steering handle 8, 8 'Driver's seat 9 Backhoe 10 Front loader 12 Handle post 17 Bucket 17a Center of rotation 19R, 19L Fender 21 Main transmission lever 22 Sub transmission lever 23 Four-wheel drive lever 25 Backhoe work detection sensor 24 Bracket 26a Main speed change first speed / sub speed change speed sensor 27 Engine speed sensor 28 Alarm buzzer 33 Support member 40 Outrigger 44 Bucket 44a Center of rotation 45 First arm 46 Second Arm 48 Bucket cylinder 49 First arm cylinder 50 Second arm cylinder 52 First boom 53 Second boom 54 Boom cylinder 55 Bucket cylinder 60a, 60b Oil passage 61a, 61b Preload line 62 Switch valve 62a Spring 65 Check valve 66 Hydraulic pump 67 Second hydraulic pump 68 Hydraulic circuit for steering 69 Mechanical relief valve 70 Electromagnetic proportional valve 71 Piston 80 Main clutch 81 Forward / reverse switching device 81F, 81R Forward / reverse clutch 82 Main transmission 83 Sub gear Transmission device 84 Drive shaft 85 Rear wheel differential device 86 Front wheel differential device 87 Rear axle 88L, 88R Brake device 89L, 89R Brake arm 90L, 90R Brake control valve 91L, 91R Brake piston 92 Forward / reverse clutch control valve 93 Forward / reverse switching lever 94 Low speed travel switch means (slow speed switch)
100 Control device

Claims (3)

A rear work machine (9) that can be freely mounted on the rear part of the machine body (2), a main transmission (82) that switches the traveling speed of the machine body (2) to one of a plurality of shift positions, and the main transmission (82). A transmission mechanism having a sub-transmission device (83) for switching to one of a plurality of shift positions and a forward / reverse switching clutch (81) for switching the traveling direction of the airframe (2) with respect to the shift position selected in Shift position detecting means (26) that can detect the shift position selected by the main transmission (82) and the sub-transmission (83), and the cockpit that can turn the seat (8, 8 ') forward or backward In a work vehicle that runs on engine power with
The low-speed travel switch means (94) for switching operation of the forward / reverse switching clutch (81) is arranged on the machine body that can be operated from the rear facing seat (8 ′), and the rear working machine (9) is being used. There is provided a work machine work sensing means (25) for sensing the presence, the work machine work sensing means (25) is sensed, the auxiliary transmission (83) is at a predetermined low speed position, and the main transmission (82) When the shift position detecting means (26) detects that the vehicle is at a predetermined low speed position and the low speed travel switch means (94) is input, the forward / reverse switching clutch (81) is actuated to activate the fuselage. (2) A work vehicle provided with a control device (100) that enables the vehicle to move forward or backward.   An engine speed detecting means (27) is provided, the engine speed detecting means (27) detects that the engine speed is equal to or less than a predetermined speed, and the work machine work detecting means (25) is a rear work machine ( 9), the shift position detecting means (26) detects that the auxiliary transmission (83) is at a predetermined low speed position and the main transmission (82) is at a predetermined low speed position. In the detected state, when there is an input from the low speed travel switch means (94), the control device (100) operates the forward / reverse switching clutch (81) to enable the aircraft (2) to move forward or backward. 2. The work vehicle according to claim 1, wherein control is performed.   A pair of left and right brake devices (88L, 88R) for braking the pair of left and right wheels (6b, 6b) and a pair of left and right brake devices (88L, 88R), respectively, toward the forward direction of the airframe (2). When a pair of brake control valves (90L, 90R) are provided, and the work machine work sensing means (25) senses that the work using the rear work machine (9) is in progress, the control device (100) causes the low speed travel switch means ( 94) any one of the brake control valves (90L, 90R) is operated by an input of 94), and any one of the corresponding brake devices (88L, 88R) can be operated independently. Item 1. The work vehicle according to Item 1.

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