JP2004017857A - Turning device for working vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the detecting operation failure of a steering angle due to the adhesion of muddy water or foreign matter, and to facilitate adjusting an operation timing to a front wheel speed increasing state. <P>SOLUTION: A middle link 54 transferring movement of a steering angle detecting mechanism 40 to a rear wheel 14 side, and a switching plate 58 capable of selectively coupling the middle link 54 and a brake device of the rear wheel 14 are provided. A speed increasing sensor 60 is disposed between the middle link 54 and the switching plate 58. When the front wheel 12 is steered over a predetermined amount, the steering angle detecting mechanism 40 detects that, so that braking is acted on the rear wheel 14 in the inner side of turning through a linkage mechanism 42. Moreover, a detection signal is outputted from the speed increasing sensor 60 toward a front wheel speed increasing device 94, and the front wheel 12 is driven at generally double speed of the rear wheel 14, so that steep turning of a machine body is enabled. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a turning device for a working vehicle, and more particularly to a turning device for a working vehicle in which a rear wheel brake inside the turning can be automatically activated based on a predetermined operation of a steering wheel.
[0002]
[Prior art]
2. Description of the Related Art In a working vehicle, an automatic turning brake device capable of automatically operating a rear wheel brake inside a turning when a steering angle of a front wheel becomes larger than a predetermined angle by operating a steering wheel is disclosed in, for example, Japanese Patent Application Laid-Open No. H6-144047. The described technique is known.
[0003]
According to this conventional technique, when the front wheel is steered to a predetermined angle or more, the pitman arm swings to the steering side, and the cam mechanism integrally fixed to the pitman arm comes into contact with the swing member, and The swing operation of the members is performed in the same direction, and the swing of the swing member pulls the mechanical linkage mechanism to brake the rear inner wheel brake mechanism.
[0004]
As a front wheel steering angle detecting device, for example, a technique described in Japanese Patent Application Laid-Open No. 2002-22436 filed by the present applicant is known.
[0005]
According to this conventional technique, a detecting device for detecting that the steering angle (turning angle) of the front wheels exceeds a predetermined value during the turning of the body is provided on a fixed vertical side that rotatably supports a front wheel supporting portion that supports the front wheels. It is attached to a case and detects the rotation of the front wheel support by the detection device.
[0006]
[Problems to be solved by the invention]
However, according to the former conventional technique described above, since the members exposed to the outside, for example, the cam mechanism and the swinging member come into contact with each other to detect the steering angle, mud, straw, etc. There is a problem in that the detection accuracy of the steering angle is degraded due to the accumulation of, and a cluttered appearance is given.
[0007]
Also, according to the latter conventional technique, the detection device for detecting the steering angle of the front wheel is mounted on the vertical case on the fixed side of the front wheel support, so that the front wheel is moved faster than the rear wheel based on the detection signal of the detection device. When switching to the speed-up state driven by the above, there is a problem that it is difficult to adjust the operation timing.
[0008]
The present invention has been made in order to solve such a problem, and an object of the present invention is to prevent a malfunction in detection of a steering angle due to adhesion of muddy water or foreign matter, and to determine an operation timing of a front wheel speed-up state. An object of the present invention is to provide a turning device for a working vehicle that can be easily adjusted.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, according to the first aspect of the present invention, a front wheel (12) is steered based on a steering operation of a steering handle (22), and a steering amount of the front wheel (12) which is equal to or greater than a predetermined value is detected. In the turning device of the working vehicle (10), which is detected by the mechanism (40), and based on the detection, the brake device (44) of the rear inner wheel (14) is braked via the linkage mechanism (42).
The link mechanism (42) includes an intermediate link member (54) that transmits a movement of the front wheel (12) based on the steering of a predetermined amount or more detected by the steering angle detection mechanism (40) to the rear wheel (14). A switching member (58) that can selectively connect the intermediate link member (54) and the brake device (44) to a side on which the brake device (44) operates and a side where the brake is released. Along with
The intermediate link member (54) is disposed between the intermediate link member (54) and the switching member (58), and electrically detects an operation of the intermediate link member (54) based on steering of the front wheel (12) by a predetermined amount or more, A speed-up sensor (60) for outputting the detection signal to a front wheel speed-up device (94) for switching to a speed-up state in which the front wheels (12) are driven at a higher speed than the rear wheels (14). Features.
[0010]
According to a second aspect of the present invention, in the turning device for a working vehicle according to the first aspect, the speed-up sensor (60) is arranged so as to be able to adjust the timing of detecting the operation of the intermediate link member (54). Features.
[0011]
[Action]
According to the present invention, the intermediate link member (54) for transmitting the movement of the steering angle detection mechanism (40) to the rear wheel (14) side, and the brake device (54) for the intermediate link member (54) and the rear wheel (14). 44), and a speed increasing sensor (60) is disposed between the intermediate link member (54) and the switching member (58). When the front wheel (12) is steered by a predetermined amount or more, this is detected by the steering angle detection mechanism (40), and a brake is applied to the rear inner wheel (14) through the linking mechanism (42), and the increase is performed. A detection signal is output from the speed sensor (60) to the front wheel speed increasing device (94), the front wheel (12) is driven at a higher speed than the rear wheel (14), and the aircraft can turn sharply.
[0012]
In addition, the code | symbol in a parenthesis mentioned above is for contrasting drawing, and does not limit this invention at all.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0014]
FIG. 1 is an external perspective view of a tractor as a working vehicle to which the present invention is applied. The tractor 10 has a traveling body 16 supported by a front wheel 12 and a rear wheel 14, and has a front hood 18. An engine 20 is mounted in the inside, and a transmission case 21 is integrally mounted below the engine 20. The driving operation unit includes a steering wheel (steering handle) 22, a seat 23, brake pedals 24R and 24L (see FIG. 3), a clutch pedal 26, and the like. Further, a main transmission lever 32 and an auxiliary transmission lever 34 are provided on the sides of the seat 23, and a safety frame 28 is attached to a rear portion of the seat 23, and a working machine such as a rotary 30 Are supported to be able to move up and down freely.
[0015]
As shown in FIG. 2, the power of the engine 20 is transmitted to the transmission case 21, and the transmission is operated by a sub-transmission lever 34 by a sub-transmission mechanism (not shown) for traveling of the transmission case 21, and the rear axle is operated. The power is transmitted to the left and right rear wheels 14 via the respective gears in the case 15. The power branched from the auxiliary transmission mechanism is transmitted to the left and right front wheels 12 via a propeller shaft (not shown), a gear in a front axle case 13, and a gear in a final case 39 (see FIG. 3). Is done.
[0016]
As shown in FIGS. 2 and 3, a cylinder device 36 is connected to the steering wheel 22 via a power steering mechanism (not shown), and knuckle arms 38, 38 are connected to the cylinder device 36. The front wheel 12 is steered by the knuckle arm 38, and the amount of steering of the front wheel 12 is detected by a steering angle detection mechanism 40 described later.
[0017]
The rear axle case 15 is provided with a brake device 44 that performs a braking operation by depressing the brake pedals 24R and 24L. When the front wheel 12 is steered by a predetermined amount or more, a mechanical linking mechanism is performed based on the steering amount. The brake device 44 of the rear wheel 14 on the inside of the turn is braked via 42. That is, by operating the steering wheel 22, the brake is applied to the rear wheel 14 inside the turning lightly without stepping on the brake pedal 24, so that the steering wheel 22 can make a small turn (a so-called auto brake turn). ).
[0018]
2 and 3, the steering angle detection mechanism 40 includes a cylinder case 46 and a cylinder rod 47 slidably fitted to the cylinder case 46. The bottom portion 46a of the cylinder case 46 and the end portion 47a of the cylinder rod 47 are opposed to each other with a predetermined gap a when the front wheel 12 is steered during straight running. It is preferable that the cylinder case 46 and the cylinder rod 47 are set to have negligible sliding resistance during expansion and contraction.
[0019]
The cylinder case 46 is connected to a knuckle arm 38 that is interlocked with the steering operation of the steering wheel 22, and the cylinder rod 47 is connected to one end arm 49 a of a sensor link 49. The knuckle arm 38 is mounted on an upper part of a final case 39 at an axial end of the front axle case 13 so as to be rotatable around a longitudinal axis of the final case 39. (Not shown).
[0020]
The sensor link 49 has forked arms 49a and 49b, and is rotatably mounted at an axial end of the front axle case 13 on a mounting shaft 48 mounted so as to face up and down. I have. Further, the other end side arm 49b of the sensor link 49 is connected to the brake device 44 of the rear wheel 14 via the above-described linkage mechanism 42.
[0021]
Here, in the present embodiment, the link mechanism 42 includes an intermediate link 54 that transmits the movement of the front wheel 12 detected by the steering angle detection mechanism 40 based on the steering of a predetermined amount or more to the rear wheel 14 side, It has a switching plate 58 that can selectively connect the link 54 and the brake device 44 to a side on which the brake device 44 is operated to brake and a side on which the brake is released.
[0022]
As shown in FIGS. 2 to 5, the link mechanism 42 includes a sensor rod 51 connected to the other end arm 49 b of the sensor link 49 via a spring 50, and a sensor rod 51 on the rear wheel 14 side. An intermediate link (intermediate link member) 54 connected by a pin 52 and rotatably mounted on a shaft 53 protruding to the side of the transmission case 21, and is mounted on the intermediate link 54 via a pin 56. And a switching plate (switching member) 58 having a hook portion 58a at the tip. The intermediate link 54 has a boss 54a and a link arm 54b and a link arm 54c integrally connected to the boss 54a and forming a bell crank shape. The switching plate 58 has a function of selectively connecting the intermediate link 54 and the brake device 44 to a side where the brake device 44 performs a braking operation and a side where the braking is released. The intermediate link 54 is constantly urged rightward in FIG. 5 by a spring 55, and the switching plate 58 is always urged leftward in FIG. 5 by a spring 59.
[0023]
Further, in the present embodiment, the operation of the intermediate link 54, which is arranged between the intermediate link 54 and the switching plate 58 and is based on the steering of the front wheel 12 by a predetermined amount or more, is electrically detected, and the detection signal is transmitted to the front wheel 12. A speed-up sensor 60 is provided for outputting to a front wheel speed-up device 94 (see FIG. 6) for switching the speed of the rear wheel 12 to a speed-up state in which the rear wheel 12 is driven at a higher speed than the rear wheel 14.
[0024]
As shown in FIG. 5, a sensor plate 54d protrudes from the boss portion 54a of the intermediate link 54, and when the sensor plate 54d rotates integrally with the boss portion 54a, the front wheel speed increasing sensor is formed. 60 contacts the detector 60a. The front wheel speed-up sensor 60 is attached to a bracket 63 disposed between the intermediate link 54 and the switching plate 58 by two bolts 67, 67. Further, two long holes (not shown) are formed in the bracket 63, and the front wheel speed-increasing sensor 60 is disposed through these long holes so that the relative position with respect to the sensor plate 54d can be adjusted. I have. The front wheel speed-up sensor 60 electrically detects the operation of the intermediate link 54 based on steering of the front wheel 12 by a predetermined amount or more, and sends the detection signal to a flow divider valve 96 (see FIG. 6) described later. The front wheels 12 are switched to a speed-up state in which the front wheels 12 are driven at a higher speed than the rear wheels 14.
[0025]
In this case, since the front wheel speed-up sensor 60 is arranged so that the relative position with respect to the sensor plate 54d can be adjusted by the long hole as described above, the timing for detecting the operation of the sensor plate 54d (when the sensor plate 54d The timing of contact with the detector 60a can be easily adjusted.
[0026]
A rear link 64 is rotatably mounted on a shaft 62 protruding to the side of the transmission case 21 behind the shaft 53 on which the intermediate link 54 is mounted. The boss portion 64a is integrally formed with a link arm 64b on the mounting base side, a link arm 64c mounted on the distal end side (free end side), and an intermediate link arm 64d. The base side link arm 64b is constantly urged rightward in FIG. 5 by a spring 65, and a pin 66 is erected on the link arm 64b. The hook 58a is engaged.
[0027]
A pin 68 is erected on the link arm 64c on the distal end, and a brake link 70 is connected to the pin 68. The brake link 70 is connected to a brake arm 72 of the brake device 44. .
[0028]
As described above, for example, when the steering wheel 22 is steered by a predetermined amount, the brake device 44 of the rear wheel 14 inside the turning is braked via the steering angle detecting mechanism 40 and the linking mechanism 42.
[0029]
Further, a pin 74 is erected on a link arm 64d in the middle of the rear link 64, and a brake rod 78 is connected to the pin 74 via a turnbuckle 76. The brake rod 78 is connected to the brake pedals 24R, 24L via a turnbuckle 80, a brake shaft 82, and pedal arms 25R, 25L, as shown in FIGS. Therefore, when the brake pedals 24R and 24L are depressed, the brake device 44 performs the braking operation via the brake rod 78.
[0030]
Although not shown, a long hole is formed in the turnbuckle 80 along the longitudinal direction of the brake rod 78, and every time the sensor rod 51 is pulled and the brake device 44 is operated, the right Alternatively, the left brake pedals 24R and 24L are prevented from operating without permission.
[0031]
4 and 5, a pin 61 is integrally fixed to a front portion of the hook portion 58a of the switching plate 58 by means such as welding, and the pin 61 is connected to the inner wire 84a covered by the outer wire 84. The distal end portion 86 is fitted in a long hole 86a. As shown in FIG. 2, the outer wire 84 is connected to an auto-brake lever 90 that is rotatable about a rotation shaft 88. The on / off operation of the autobrake lever 90 sets or cancels the brake device 44 of the rear wheel 14 inside the turning when the front wheel 12 is steered by a predetermined amount or more. be able to.
[0032]
Further, the auto brake lever 90 is connected to the sub-shift lever 34 via an outer wire 92. When the sub-shift lever 34 is operated to the high speed side, the auto brake lever 90 is turned to the cut side in consideration of running safety. It is designed to be operated in conjunction with.
[0033]
Next, FIG. 6 is a diagram showing a part of the hydraulic circuit. As described above, when the front wheel 12 is steered by a predetermined amount or more (for example, 40 degrees or more), the front wheel speed increasing sensor 60 outputs the flow divider valve 96. A detection signal is sent to the solenoid 96a of the first embodiment, and pressure oil is supplied to the front wheel speed increasing device 94 by the flow divider valve 96.
[0034]
That is, in FIG. 6, the pressurized oil stored in the bottom of the transmission case 21 is sent to a pump 98 via a filter 97, supplied from the pump 98 to a flow divider valve 96, and sent from the flow divider valve 96 to a working machine. To the side or to the front wheel speed increasing device 94. The front wheel speed increasing device 94 is disposed in the transmission case 21, and when the pressure oil is supplied to the front wheel speed increasing device 94, the front wheel 12 is moved more rearward than the rear wheel 14 in the front wheel speed increasing device 94. The mode is switched to a speed-up state in which driving is performed at a high speed (front wheel speed-up state).
[0035]
FIG. 7 is a cross-sectional view when the front wheel speed increasing device 94 is in a four-wheel drive state. At this time, the drive gear 110 on the drive shaft (not shown) is engaged with the 4WD gear 111 and the sleeve 112 Is pressed in the direction of the arrow by the return spring 113, and the ball 114 enters the groove of the 4WD shaft 115, and the ball clutch is engaged. Therefore, power is transmitted from the 4WD gear 111 to the 4WD shaft 115, and the 4WD shaft 115 is rotating at a normal rotation speed.
[0036]
Next, FIG. 8 is a cross-sectional view when the front wheel speed increasing device 94 is switched to the front wheel speed increasing state. When the steering angle of the front wheels 12 becomes a predetermined value or more (for example, 40 degrees or more), as described above, , A pump 98 supplies pressure oil to a front wheel speed increasing device 94 via a flow divider valve 96. In the front wheel speed increasing device 94, the sleeve 112 is moved in the direction of the arrow by the pressure oil, the ball 114 is disengaged from the groove of the 4WD shaft 115, and the ball clutch is disengaged. Further, the wet-type multi-plate clutch 116 is pressed by the sleeve 112 in the same direction, the front wheel speed increasing gear 117 is connected to the 4WD shaft 115, and the 4WD shaft 115 rotates at almost twice the speed, and the propeller shaft ( (Not shown), the front wheel 12 rotates at approximately twice the speed.
[0037]
Next, the operation will be described.
[0038]
As shown in FIG. 3, when the vehicle is traveling straight, the left and right front wheels 12 and 12 are directed substantially parallel and forward, and in this state, the bottom 46 a of the cylinder case 46 of the steering angle detection mechanism 40 and the end of the cylinder rod 47. The portion 47a is disposed so as to face a predetermined gap a. In this state, the auto brake lever 90 is operated to the entry side to enable a small turn (auto brake turn).
[0039]
Next, for example, the steering wheel 22 is steered by a predetermined amount (for example, 40 degrees or less) in the left turning direction. Then, as shown in FIG. 9, the rod of the cylinder device 36 extends to the left, and the knuckle arm 38 is rotated counterclockwise around the axis of the final case 39. The rotation of the knuckle arm 38 also moves the cylinder case 46 in the tangential direction. At this time, since a predetermined gap a is formed between the cylinder case 46 and the cylinder rod 47 on the left side of the machine body, even if the cylinder case 46 moves, the cylinder rod 47 does not move. Eventually, the predetermined gap a becomes zero due to the movement of the cylinder case 46, and the further steering of the steering wheel 22 by a predetermined amount or more (for example, 40 degrees or more) causes the cylinder rod 47 to move, and the sensor link 49 causes the mounting shaft 48 to move. It rotates counterclockwise in the figure as the center.
[0040]
In this case, since the cylinder rod 47 is slidably fitted to the cylinder case 46, muddy water or foreign matter adheres to the steering angle detection mechanism 40 including the cylinder rod 47 and the cylinder case 46, and the steering angle detection is performed. It is possible to prevent the malfunction of the mechanism 40 from occurring.
[0041]
As a result, the spring 50 and the sensor rod 51 are pulled in the direction of the arrow, and the intermediate link 54 in FIG. By the rotation of the intermediate link 54, the switching plate 58 moves in the same direction via the link arm 54c and the pin 56. This movement of the switching plate 58 causes the hook portion 58a to pull the pin 66 in the same direction, so that the rear link 64 rotates counterclockwise about the shaft 62. By the rotation of the rear link 64, the brake link 70 is pulled via the link arm 64c and the pin 68, the brake arm 72 is operated, and the brake device 44 of the rear wheel 14 inside the turning is operated. For this reason, a small turn is possible.
[0042]
In addition, although the case where the body turns left has been described above, the same applies to right turn. When the auto brake lever 90 is operated to the cut side, the outer wire 84 is pulled, and the pin 61 at the tip of the inner wire 84a is pulled in the same direction. , And the hook portion 58 a comes off the pin 66. Therefore, in this state, even if the steering rod 22 is steered by a predetermined amount or more and the sensor rod 51 is pulled, the brake device 44 does not operate.
[0043]
When the sub-shift lever 34 is operated to the high-speed side, the body is in a high-speed running state, so that the auto-brake lever 90 is operated to the off-side via the outer wire 92 in conjunction with the operation of the sub-shift lever 34. It has become. Then, even if the steering wheel 22 is steered by a predetermined amount or more in this state, the brake device 44 of the rear wheel 14 inside the turning is not operated for the same reason as described above.
[0044]
Further, when the steering wheel 22 is steered by a predetermined amount or more (for example, 40 degrees or more), as shown in FIG. 5, when the intermediate link 54 constituting the linking mechanism 42 rotates clockwise (in the direction of the arrow) about the shaft 53, as shown in FIG. The sensor plate 54d presses the detector 60a of the front wheel speed-up sensor 60, and a signal is sent from the front wheel speed-up sensor 60 to the solenoid 96a of the flow divider valve 96 in FIG.
[0045]
As a result, pressure oil is supplied from the pump 98 to the front wheel speed increasing device 94. In the front wheel speed increasing device 94, the sleeve 112 moves in the direction of the arrow in FIG. The ball clutch is disengaged from the groove. Further, the wet multi-plate clutch 116 is pressed by the sleeve 112 in the same direction, the front wheel speed increasing gear 117 is connected to the 4WD shaft 115, and the 4WD shaft 115 rotates at almost twice the speed, and the front wheel 12 is rotated. It rotates at almost twice the speed.
[0046]
As described above, when the steering wheel 22 is steered by a predetermined amount or more (for example, 40 degrees or more), the brake device 44 of the rear wheel 14 on the inside of the turn is operated, and the front wheel 12 rotates at approximately twice the speed. The aircraft can turn sharply with a smaller radius than the so-called automatic brake turn.
[0047]
In the above, when the auto brake lever 90 is operated to the off side or the auxiliary speed change lever 34 is operated to the high speed side, the switching plate 58 is moved, and the hook portion 58a is detached from the pin 66, so-called, so-called. Then, the function of the automatic brake turn is released, but also in this case, since the sensor plate 54d presses the detector 60a of the front wheel speed increasing sensor 60, the front wheel speed increasing device 94 operates. In order to make this possible, the front wheel speed increasing sensor 60 is arranged between the intermediate link 54 and the switching plate 58.
[0048]
Further, since the mounting position of the front wheel speed increasing sensor 60 can be adjusted by the long hole formed in the bracket 63, the timing at which the sensor plate 54d presses the detector 60a of the front wheel speed increasing sensor 60 can be easily adjusted. Accordingly, the operation of the brake device 44 of the rear wheel 14 on the inside of the turn based on the steering of the steering wheel 22 by a predetermined amount or more and the operation timing of the front wheel speed increasing device 94 can be arbitrarily adjusted.
[0049]
【The invention's effect】
As described above, according to the first aspect of the present invention, the link mechanism switches between the intermediate link member that transmits the movement based on the steering of the front wheel detected by the steering angle detection mechanism by a predetermined amount or more to the rear wheel side, and the switching mechanism. And a speed-up sensor that electrically detects the operation of the intermediate link member and outputs a detection signal to the front wheel speed-up device. Can be detected in the central part of the aircraft remote from For this reason, there is no risk of malfunction due to the adhesion of muddy water and the like, and even in the case of arranging signal lines from the steering angle detection unit to the control unit, it is necessary to eliminate the problems caused by the adhesion of muddy water and the like. Can be. Furthermore, according to the present invention, the steering angle of the front wheel is detected by the steering angle detection mechanism by a predetermined amount or more, and the detection signal is used for operating the front wheel speed increasing device. This eliminates the need for a separate device, and can be manufactured at low cost.
[0050]
According to the second aspect of the present invention, the speed increase sensor is arranged so as to be able to adjust the timing of detecting the operation of the intermediate link member. The timing up to activation can be easily adjusted.
[Brief description of the drawings]
FIG. 1 is an external perspective view of a tractor to which the present invention is applied.
FIG. 2 is a sectional side view of the same.
FIG. 3 is a plan view of the same.
FIG. 4 is an enlarged plan view of a main part of FIG. 3;
FIG. 5 is an enlarged side view of a main part of the linkage mechanism.
FIG. 6 is a diagram showing a hydraulic circuit in the present embodiment.
FIG. 7 is a cross-sectional view of the front wheel speed increasing device when the front wheel speed increasing device is in a four-wheel drive state.
FIG. 8 is a cross-sectional view of the front wheel speed increasing device when the front wheel speed increasing device is switched to a front wheel speed increasing state.
FIG. 9 is a plan view showing an operation state of a steering angle detection mechanism when the steering wheel is turned left.
[Explanation of symbols]
10 Tractor (work vehicle)
12 Front wheel 13 Front axle case 14 Rear wheel 21 Transmission case 22 Steering wheel (steering handle)
38 Knuckle arm 39 Final case 40 Steering angle detection mechanism 42 Linkage mechanism 44 Brake device 46 Cylinder case 46a Bottom part 47 Cylinder rod 47a End part 49 Sensor link 51 Sensor rod 54 Intermediate link (intermediate link member)
54a Boss 54b Link arm 54c Link arm 54d Sensor plate 58 Switching plate (switching member)
60 Front wheel speed-up sensor (speed-up sensor)
60a Detector 63 Bracket 94 Front wheel speed increasing device 96 Flow divider valve 115 4WD shaft 116 Wet multi-plate clutch

Claims (2)

The front wheels are steered based on the steering operation of the steering wheel, the steering amount of the front wheels is detected by a steering angle detection mechanism by a steering angle detection mechanism, and based on the detection, the brake device of the rear wheel inside the turning is braked via the linkage mechanism. In a turning device of an operating working vehicle,
The linking mechanism includes: an intermediate link member that transmits, to the rear wheel side, a movement of the front wheels detected by the steering angle detection mechanism based on steering of a predetermined amount or more, to the rear wheel side; A switching member that can be selectively connected to a side on which braking is performed and a side on which braking is released,
It is disposed between the intermediate link member and the switching member, electrically detects the operation of the intermediate link member based on steering of the front wheel by a predetermined amount or more, and outputs the detection signal at a higher speed than the front wheel than the rear wheel. A speed-up sensor that outputs to a front wheel speed-up device that switches to a speed-up state driven by
A turning device for a working vehicle, comprising: The speed-up sensor, arranged to be able to adjust the timing of detecting the operation of the intermediate link member,
The turning device for a working vehicle according to claim 1, wherein:

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