JPH07100453B2 - Forced switching link mechanism in front wheel steering vehicle equipped with speed-up switching mechanism - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a forced switching link mechanism in a front wheel steering vehicle equipped with a speed increasing switching mechanism.

[0002]

2. Description of the Related Art Conventionally, for example, a tractor has a speed-up switching mechanism that is configured to drive front wheels and rear wheels and that can switch between constant speed and speed between a front-wheel drive shaft and a front axle case. The speed increase switching mechanism is interlocked with the high / low speed switching lever so that the speed increasing switching mechanism operates only when the low speed switching operation of the lever is performed.

Therefore, a tractor that performs a low speed switching operation when turning in a field can be turned and can turn with a small turning radius, thus improving work efficiency.

[0004]

However, when the tractor is traveling on a sloping ground and the vehicle is turned at a low speed switching operation, there is a danger that the tractor will fall due to a sudden turn.

[0005]

SUMMARY OF THE INVENTION According to the present invention, a front wheel and a rear wheel are configured to be drivable, and a front wheel has a speed increasing switching mechanism in which the front wheel can be switched between constant speed and speed increasing relative to the rear wheel. The speed increase switching mechanism is interlocked with a high / low speed switching lever that can be selectively switched between a low speed side position where speed increase switching operation is possible and a high speed side position where speed increase switching operation is not possible. Between the high / low speed switching lever and the speed increasing / switching mechanism, there is a forced switching link mechanism for controlling the on / off of the speed increasing / switching operation of the speed increasing / switching mechanism regardless of the lever position of the high / low speed switching lever. Then, the speed-up switching mechanism performs the speed-up operation only when the forced switching link mechanism is in the ON state and the high-low speed switching lever is located at the low-speed side, and the high-low speed switching lever is at the low-speed side. Even if it is located at , In which according to the forced changeover link mechanism in a front wheel steering vehicle having a speed increasing switching mechanism, characterized in that so as to perform the speed increasing release of the speed increasing switching mechanism forcibly.

Further, according to the present invention, the front wheels and the rear wheels are configured to be drivable, and the front wheels are provided with a speed increasing switching mechanism which is capable of switching the front wheels with respect to the rear wheels between constant speed and speed increasing. , The high speed / low speed switching mechanism is linked to a high / low speed switching lever which can be selectively switched between a low speed side position where the speed increasing switching operation can be performed and a high speed side position where the speed increasing switching operation cannot be performed. A forced switching link mechanism is provided between the switching lever and the speed increasing switching mechanism to control the on / off of the speed increasing switching operation of the speed increasing switching mechanism regardless of the lever position of the high / low speed switching lever. The compulsory switching link mechanism is linked with a compulsory switching lever that can be selectively switched between an input position where the speed increasing switching mechanism can perform speed increasing switching operation and a cut side position where speed increasing switching operation cannot be performed. , Only when the switching lever is in the on position and the high / low speed switching lever is on the low speed side. In addition to enabling the switching mechanism to perform speed-up operation, even when the high / low speed switching lever is located on the low speed side, the speed-up switching mechanism is forced to release the speed-up by operating the forced switching lever to the cut position. Further, the forcible switching link mechanism is further provided with a detecting means for detecting the entering position of the forcible switching lever and an alarm means for operating in cooperation with the detecting means. Have.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the embodiments shown in the accompanying drawings.

In FIG. 1, A is a tractor, and the tractor A has front wheels and rear wheels 2 attached to its front and rear portions, respectively, and both the front wheels 1 and the rear wheels 2 will be described below. It is driven by a drive mechanism that operates.

That is, in the drive system diagram of the drive mechanism shown in FIG. 2, 3 is an engine, 4 is a main clutch, 5 is a main transmission, 6 is an auxiliary transmission, and 7 is a rear wheel diff. The differential yoke shaft 8 of No. 7 is linked to each rear wheel 2 via a final reduction gear 9. Reference numeral 10 is a rear wheel brake provided on the outer end of each differential yoke shaft 8.

In the above structure, the main transmission 5,
The auxiliary transmission 6 is built in the mission case 84 '.

Reference numeral 11 denotes a front wheel drive system. The front wheel drive system 11 is connected to a front wheel drive shaft 14 connected via a sub transmission 6 gear train 12 and a universal joint 13, and to the front wheel drive shaft 14. The front wheel differential device 15 is connected to each of the differential yoke shafts 16 of the front wheel differential device 15 via a gear train 17, and the front wheel 1 is steerable around a kingpin.

In the front wheel drive system 11, the front wheel drive shaft 14
A speed increase switching mechanism B is provided between the front wheel differential device 15 and the front wheel differential device 15.

The structure of the speed increasing switching mechanism B will be described in detail with reference to FIGS. 3 and 4.

In the figure, reference numeral 21 denotes a front axle case which incorporates the front wheel differential device 15 and is supported by a case swing support portion 21a so as to be swingable left and right, and the front axle case 21 is provided at the rear portion thereof. The base end of a tubular casing 20 extending rearward is provided so as to project.
The middle portion of the 20 is supported by a bearing 24 having an upper end fixed to the machine frame 22.

A clutch housing 49 (see FIG. 7) and an oil pan (not shown) are provided at the bottom of the machine frame 22, and the tubular casing 20 is arranged so as not to contact them.

Further, the tubular casing 20 has a pinion shaft 29 having a bevel gear 27, which meshes with the gear train of the front wheel differential device 15 and which engages with a gear train of the front wheel differential device 15, from the front wheel differential device 15 toward the front wheel drive shaft 14. A speed-up switching mechanism input shaft 30 whose rear end is interlocked with a front wheel drive shaft 14 by a universal joint 13 is arranged in series.

Further, 31 is an intermediate rotary cylinder which is concentrically and relatively rotatably attached over substantially the entire length of the pinion shaft 29. The intermediate rotary cylinder 31 is slidable in the axial direction at its rear end side, but splined. The sliding cam body 32 that rotates integrally with the intermediate rotary cylinder 31 is attached by the
Via a dog clutch 33, a flange 34 connected to the rear end side of the speed increasing switching mechanism input shaft 30 via a spline is detachably engaged.

The sliding cam body 32 is axially moved by a swing hawk 36 pivotally supported by a yoke support shaft 35. The swing hawk 36 is a steering mechanism D which will be described later. The dog clutch 33 can be engaged and disengaged by the swinging operation of the operating mechanism C, and the multi-plate clutch 37 described below can be operated.

That is, 37 is the middle of the intermediate rotary cylinder 31,
The multi-disc clutch 37 is mounted at a position adjacent to the sliding cam body 32, and the multi-disc clutch 37 is provided with a spring 38 by the axial movement of the sliding cam body 32 caused by the swing of the swing yoke 36.
Can be compressed, the intermediate rotary cylinder 31 can be fixed to the tubular casing 20, and its rotation can be stopped.

Reference numeral 40 denotes a speed increasing differential mechanism provided at the front end of the pinion shaft 29. The differential mechanism 40 has a rotary housing 41 concentrically mounted around the rear end of the pinion shaft 29,
A bevel gear 42 having an axis line in a direction orthogonal to the axis line of the pinion shaft 29 is attached to the inner surface of the rotary housing 41, and a bevel gear 43 and an intermediate rotary cylinder in which the front and rear surfaces of the bevel gear 42 are fixed to the rear end of the pinion shaft 29, respectively. It meshes with a bevel gear 44 formed integrally with the rear end of 31.

Next, the speed increasing switching mechanism B having the above structure
The action of will be described.

When the engine 3 is started and the main clutch 4 is connected, the power of the engine 3 is supplied to the main clutch 4, the main transmission 5, the auxiliary transmission 6, the rear wheel differential device 7 and the final reduction gear 9.
Is transmitted to each rear wheel 2 via.

On the other hand, since the auxiliary transmission 6 is transmitted to each front wheel 1 via the front wheel drive shaft 14, the speed increasing switching mechanism B, and the front wheel differential device 15, the tractor A has four front wheels 1 and two rear wheels 2. The wheels will drive as driving wheels.

When driving straight ahead, the front wheels 1 and the rear wheels 2 are driven at the same speed.
The description will be made with reference to the drive system illustration shown in FIG.

That is, the steering mechanism D, which will be described later, has a swing fork 36.
When the steering is not carried out to the extent that actuates, the multi-plate clutch 37 is not actuated, and therefore the intermediate rotary cylinder 31 is not fixed to the tubular casing 20. Meanwhile, dog clutch
The speed increase switching mechanism input shaft 30 is in a state of being integrally connected to the intermediate rotary cylinder 31 by 33.

Therefore, the rotation of the front wheel drive shaft 14 is controlled by the input of the speed-increasing switching mechanism 30 to the rotary housing 41 and the intermediate rotary cylinder 31.
Then, the bevel gear 42, the bevel gear 43, the pinion shaft 29, the bevel gear 44, and the intermediate rotary cylinder 31 are rotated at the same speed as the front wheel drive shaft 14, and then the front wheel differential device 15 and the differential yoke shaft 16 are used. 1 will be transmitted.

On the other hand, when the steering mechanism D is steered to the extent that the swing hawk 36 is operated, the swing hawk 36 presses the multi-plate clutch 37 via the sliding cam body 32, whereby the intermediate rotary cylinder 31 is fixed to the tubular casing 20, and the dog clutch 33 is disengaged to disconnect the speed increase switching mechanism input shaft 30 from the intermediate rotary cylinder 31.

Therefore, the rotation of the front wheel drive shaft 14 is transmitted from the speed-increasing switching mechanism input shaft 30 to the rotary housing 41.
Only the power transmission path of the bevel gear 42 → the bevel gear 43 → the pinion shaft 29 → the front axle case 21 goes, and the relative rotation between this and the rotary housing 41 forms a differential gear mechanism, and the pinion shaft 29 and the bevel gear 27. Means to rotate at twice the speed of the front wheel drive shaft 14, and then be transmitted to the front wheel 1 via the front wheel differential device 15 and the front wheel yoke shaft 16.

Therefore, the tractor A can turn at a small turning radius without slipping.

In the above speed increasing action, the speed increasing switching mechanism B according to the present embodiment includes the speed increasing differential mechanism 40 including the multi-plate clutch 37 and the operating gear device.
Since the speed can be gradually increased steplessly and the multi-plate clutch 37 absorbs the load, the field is not damaged.

Next, with reference to FIGS. 5 to 7, the structure of the operating mechanism C provided for operating the speed increase switching mechanism B in conjunction with the steering operation of the steering mechanism D, which will be described later, will be described.

5 to 7, reference numeral 50 denotes a pitman arm fulcrum shaft horizontally rotatably mounted on the clutch housing 49. The pitman arm fulcrum shaft 50 is arranged substantially directly below a steering mechanism D described later. ing.

And, such a pitman arm fulcrum shaft 50
Is operatively connected to a yoke support shaft 35 to which the above-mentioned swing hawk 36 is fixed via a path described below.

That is, the pitman arm fulcrum shaft 50 is shown in FIG.
And, as shown in FIG. 7, movable in the axial direction, and
The movable sleeve 51, which rotates integrally with the fulcrum shaft 50, has an isosceles triangular pressing roller mounting plate 52 fixed to one end side thereof with its apex facing forward.

A vertical pressing roller 53 is rotatably supported on the upper and lower side surfaces of the rear portion of the pressing roller mounting plate 52.

Further, in FIGS. 6 and 7, reference numeral 54 denotes a speed increasing member in which a pitman arm fulcrum shaft 50 is freely inserted into a rectangular notch opening 55 provided at a rear portion thereof at a position corresponding to the vertical pressing roller 53. It is a switching operation plate. Further, the speed increase switching operation plate 54 has an isosceles triangle shape with its apex facing forward, like the pressing roller attachment plate 52.

In this structure, when the pitman arm fulcrum shaft 50 is rotated by the steering mechanism D, which will be described later, with the moving sleeve 51 moving and the vertical pressing roller 53 moving to the position indicated by the solid line, the vertical pressing roller 53 is rotated.
When 53, 53 swing together with the pressing roller mounting plate 52 and come into contact with and press against the speed increasing switching operation plate 54, the speed increasing switching operation plate 54
Will move forward.

Reference numeral 56 denotes a connecting rod whose base end is fixed to the front portion of the speed increasing switching operation plate 54 and whose tip extends toward the speed increasing switching mechanism B. The tip of the connecting rod 56 is The base end is connected to the tip of the swing lever 57 fixed to the above-mentioned yoke support shaft 35.

With this structure, the forward movement of the speed increase switching operation plate 54 causes the swing lever 57 and the yoke support shaft 35 and swing yoke 36 which are integral with the swing lever 57 to swing. Clutch 37 is engaged, speed increase switching mechanism B
Will be switched to speed-up mode.

The connecting rod 56 has a speed increasing switching operation plate.
An impact absorbing mechanism E is attached to prevent the speed increasing switching mechanism B from being destroyed when the 54 side fails.

In this embodiment, the shock absorbing mechanism E is
As shown in FIGS. 6 and 7, a piece piece 60 having a through hole into which the tip of the connecting rod 56 is slidably inserted is provided at the tip of the swing lever 57, and a stopper nut 61 is provided in the middle of the connecting rod 56.
The sleeve 62 is concentrically attached to the connecting rod 56 between the stopper nut 61 and the piece piece 60 so as to be movable in the axial direction, and a spring disposed inside the sleeve 62 at the tip of the sleeve 62. The contact cylinder 64 is urged forward by 63, and the tip of the contact cylinder 64 presses the piece piece 60 so that the rocking lever 57 can rock.

Next, the structure of the steering mechanism D for operating the operation mechanism C will be described with reference to FIGS.

In the figure, reference numeral 70 denotes a steering rod which is provided in an inclined state in the driver's seat. The steering rod 70 has a steering handle 71 attached to the upper end thereof, and a base end thereof attached to a gear box stay 72. It is connected to the 73 input shaft.

The output shaft of the gearbox 73 is
The base end of a swing lever 74 that swings up and down in conjunction with the rotation of the steering handle 71 is connected, and the tip of the swing lever 74 is connected to the pitman arm fulcrum shaft 50 that is disposed directly below the steering handle 71. Swing lever 75 and drag rod 76 fixed to
Are linked by.

Further, the pitman arm support shaft 50 has
The base end of the pitman arm 77 is fixed, and the tip of the pitman arm 77 is connected by a steering arm 78 attached to the left front wheel 1 and a drag rod 79.

A steering arm attached to the left and right front wheels 1
78 and 78 are connected by a tie rod 80.

With this structure, when the steering wheel 71 is rotated, the left and right wheels 1, 1 can be turned through the drag rod 76, the pitman arm 77, the drag rod 79, the steering arm 78, and the tie rod 80.

In the steering operation, the pitman arm support shaft 50 also inevitably rotates, and the rotation causes the operation mechanism C to operate and the speed increase switching mechanism B to operate as described above. become.

In such a structure, the gist of the present invention is that the speed increasing switching mechanism B can be selectively switched between a low speed side position where the speed increasing switching operation is possible and a high speed side position where the speed increasing switching operation is not possible. In addition to being linked to the low speed switching lever L, between the high / low speed switching lever L and the speed increasing switching mechanism B, regardless of the lever position of the high / low speed switching lever L, the speed increasing switching operation of the speed increasing switching mechanism B is performed. A forced switching link mechanism M for controlling ON / OFF is provided, and the forced switching link mechanism M is in the ON state, and
Only when the high / low speed switching lever L is located on the low speed side, the speed increase switching mechanism B performs the speed increasing operation, and even when the high / low speed switching lever L is located on the low speed side, the forced switching link mechanism M is used. This is because the speed-up switching mechanism B is forcibly released from the speed-up switching mechanism by switching the switch to the OFF state. This configuration will be described in detail below with reference to FIGS. 6, 7, and 11 to 13. To do.

That is, in FIG. 6 and FIG. 7, 90, 90 are restriction plates mounted on the moving sleeve 51 at intervals in the axial direction.

And, between the regulation plates 90, 90,
A front end of a swing lever 92, which is pivotally supported at its center by a support shaft 91, is inserted, while one end of the swing lever 92 is arranged on the left side of the seat 95 at the rear end. The other end of the switching wire 93 bound to the high / low speed switching lever L (see FIG. 1) is bound.

Numeral 96 is an urging spring interposed between the swing lever 92 and the clutch housing 49, and the urging force of the urging spring 96 constantly indicates both the moving sleeve 51 and the pressing roller 53 in solid lines. Since the pressure roller 53 has moved to the position and is in a position corresponding to the speed increase switching operation plate 54, when the steering handle 71 is turned, the pressure roller 53 also swings in conjunction with this and presses the operation plate 54. The speed increasing switching mechanism B can be operated (hereinafter, this state is referred to as the “on” state).
Therefore, when the vehicle speed is low, the front wheel 1 can be turned at a double speed, and a sharp turn can be made.

Further, the high / low speed switching lever L (see FIG. 1)
Is switched to the high speed side against the bias of the bias spring 96, the swing lever 92 swings via the switch wire 93, and the swing causes the moving sleeve 51 to move from the solid line position to the virtual position. Moves to the linear position, and with this movement, the vertical pressing roller 53 also engages with the speed increasing switching operation plate 54 (solid line position)
To the non-engagement position (imaginary line position) (hereinafter, this state is referred to as the “off” state).

Therefore, at a high speed, even if the Pippman arm support shaft 50 rotates, the pressing roller 53 is provided with the speed increasing switching operation plate.
Since it is in the non-engagement position with respect to 54, it cannot press the operation plate 54 to move it forward. Therefore, the speed increasing switching mechanism B does not work, and the front wheel 1 does not turn when turning on the road. You can secure safe driving without accidentally turning at double speed.

Moreover, in the present invention, as shown in FIGS. 11 to 13, the forced switching link mechanism M is provided between the high / low speed switching lever L and the base end of the switching wire 93, so that even at low speeds. The speed-up switching mechanism B is forcibly released from the speed-up.

That is, the compulsory operation link mechanism M includes a first link mechanism 81 that is interlocked with the high / low speed switching lever L, a second link mechanism 82 that is directly interlocked with the switching wire 93, and a second link mechanism 82.
It comprises a compulsory switching lever L'interlockingly connected to the link mechanism 82.

The first and second link mechanisms 81 and 82 are
Lever spindle protruding from the left side of the mission case 84 '
The first link mechanism 81 is interlockingly connected to the high / low speed switching lever L via a lever link 85 between the 83 and the auxiliary shift shifter shaft 84 in parallel with each other.

Moreover, each link mechanism 81, 82 has its base end pivotally supported at the tip end of the first and second telescopic links 81a, 82a whose base ends are pivotally supported by the lever support shaft 83, and at its base end by the auxiliary shift shifter shaft 84. First, second
The first and second arms are formed by connecting the middle parts of the arms 81b and 82b.
Long holes 81c, 82 are formed in the longitudinal direction at the tips of the expansion links 81a, 82a.
c is provided, and the first and second arms 81b and 82b are provided in the same long holes 81c and 82c.
The connecting pins 81d and 82d attached to the middle part are loosely fitted.

Further, at the tip of the first arm 81b, there is provided a locking portion 81e whose rear end side is notched, and the locking portion 81e is the second
The arm 82b is configured to engage with the extended end of the wire connecting pin 86 provided at the tip of the arm 82b.

Therefore, the forced switching link mechanism M is
It operates as follows.

That is, when the compulsory switching lever L'is rotated upward, the second telescopic link 82a of the second link mechanism 82 is telescopically actuated so that the second arm 82b is connected to the tip of the link 82a. Is rotated forward by the urging force of the urging spring 96, and the switching wire 93 connected to the tip end of the second arm 82b is slid forward, so that the speed increasing switching mechanism B is in the "ON" state. Becomes In this case, since the front wheel 1 side is accelerated more than the rear wheel 2 when the vehicle body turns, a sharp turn is possible.

Further, when the lever L'is turned downward, the second telescopic link 82a is extended in a straight manner, and the second arm 82b is turned rearward, so that the arm is rotated backward. The switching wire 93 connected to the tip portion of the 82b is pulled and slid rearward against the urging force of the urging spring 96, and the speed increasing switching mechanism B is turned off. In this case, the front wheel 1 and the rear wheel 2 can turn in a substantially constant speed state, that is, in a standard state.

When the lever L'is set to the "ON" state, the extended end of the wire connecting pin 86 provided at the tip of the second arm 82b is locked by the locking portion 81e of the first arm 81b. , The first arm 81b is also pivoted forward, and the high / low speed switching lever L is pivoted forward to the low speed switching position via the first expansion link 81a and the lever link 85 interlockingly connected to the first arm 81b. Is.

When the high / low speed switching lever L is rotated rearward to the high speed switching position from such a state, the first extension link 81a is extended via the lever link 85 and the first arm 81b.
And the second arm 82b together with the first arm 81b via the locking portion 81e of the first arm 81b so as to turn the speed increasing switching mechanism B into the "OFF" state. Is.

Next, if the compulsory switching lever L'is kept in the "OFF" state, even if the high / low speed switching lever L is switched to the low speed side or the high speed side, the expansion and contraction operation of the first link 81a and the first link 81a are performed.
The forward / backward rotation operation of the arm 81b does not interlock with the second arm 82b at all, and the speed increasing switching mechanism B is kept in the "OFF" state.

Further, in FIG. 11, 87 is an alarm lamp or an alarm means such as an alarm buzzer, 88 is a detection means such as a contact switch for detecting the entry position of the forced switching lever L ', and 89 is an operating arm, When the compulsory switching lever L'is set to the "ON" state, the operating arm 89 is interlocked to bring the detecting means 88 into the connected state, and the alarm means 87 is lit to alert the operator.

The detecting means 88 may be connected in conjunction with the operation of the speed increase switching operation plate 54 so that the alarm means 87 is turned on.

In this way, when the speed increasing switching mechanism B is in the "ON" state at a low speed, the operator's attention is called by the alarm lamp or the alarm buzzer which is the alarm means 87 to ensure the operational safety. It is good to be able to keep.

[0069]

According to the present invention, when making a turn on a road or the like, the speed increase switching mechanism does not work at high speed, so that the front wheels do not make a double-speed turn, and safe driving can be ensured. Also, if the forced switching link mechanism is operated so that the speed-up switching mechanism speeds up only during low-speed switching, when the high-low speed switching lever is operated to perform low-speed switching and the turning operation is performed, The speed increase switching mechanism speeds up the operation so that the machine can suddenly turn.

On a sloping ground, if the forced switching link mechanism is operated so that the speed-up switching mechanism does not accelerate even during low-speed switching, the high-low speed switching lever causes a low-speed switching operation as well as a turning operation. Even if the operation is performed, since the speed increase switching mechanism does not perform the speed increasing operation, the machine does not turn sharply, and there is no danger of the machine falling over even on a sloping ground.

Further, a forcible switching lever for operating the above forcible switching link mechanism is provided, and a detection means for detecting the entry position of the forcible switching lever and an alarm means for operating in conjunction with the detection means are provided in series. Since the alarm means is configured to operate when the forced switching lever is in the "ON" state, it is possible to illuminate the operator by turning on an alarm lamp, which is the alarm means. It can be performed more safely and various operations can be performed efficiently.

[Brief description of drawings]

FIG. 1 is a side view of a front wheel steering vehicle (tractor) including a forced switching link mechanism according to the present invention.

FIG. 2 is a drive system diagram of the same.

FIG. 3 is a layout explanatory view of a speed increasing switching mechanism.

FIG. 4 is an enlarged structural explanatory view of a speed increasing switching mechanism.

FIG. 5 is a structural explanatory view of an operating mechanism.

FIG. 6 is an enlarged explanatory view of the operating mechanism.

FIG. 7 is an enlarged explanatory view of the operating mechanism.

FIG. 8 is a side view of the steering mechanism.

FIG. 9 is a rear view of the same.

FIG. 10 is a plan view of the same.

FIG. 11 is an enlarged explanatory view of the forced switching link mechanism.

FIG. 12 is an exploded explanatory view of the link mechanism.

13 is a cross-sectional view taken along the line I-I of FIG.

[Explanation of symbols]

 A tractor B speed increase switching mechanism C operating mechanism D steering mechanism M forced switching link mechanism L high / low speed switching lever L'forced switching lever 1 front wheel 2 rear wheel 14 front wheel drive shaft 21 front axle case 50 pitman arm support shaft 73 handle gearbox 87 Alarm means 88 Detection means

Claims (2)

[Claims] 1. A front wheel (1) and a rear wheel (2) are configured to be drivable, and the front wheel (1) has a constant velocity between the front wheel (1) and the rear wheel (2) .
A speed increase switching mechanism (B) that can freely switch the speed increase is installed, and the speed increase switching mechanism (B) is increased to the low speed side position where the speed increase switching operation is possible.
Can be selectively switched to a high-speed position where speed switching operation is not possible
High speed and low speed switching lever (L)
Between the switching lever (L) and speed increasing switching mechanism (B), high and low speed
Acceleration switching mechanism regardless of the lever position of the switching lever (L)
(B) Forced switching link for controlling on / off of speed-up switching operation
The mechanism (M) is installed, and the forced switching link mechanism (M) is in the ON state, and the high / low speed
Acceleration switching only when the switching lever (L) is located on the low speed side
Allow mechanism (B) to perform speed-up operation and
Even when the conversion lever (L) is located on the low speed side, forced
With state off changeover link mechanism (M), octopus to allow the accelerated release of the speed increasing switching mechanism (B) to force
And a compulsory switching link mechanism in a front-wheel steering vehicle, which is equipped with a speed-up switching mechanism. 2. The front wheel (1) and the rear wheel (2) can be driven.
However, the front wheel (1) should have the same speed as the front wheel (1) with respect to the rear wheel (2).
The speed increase switching mechanism (B) that can switch the speed increase freely
Increase the switching mechanism (B) to the low-speed side position where the speed-up switching operation is possible.
Can be selectively switched to a high-speed position where speed switching operation is not possible
High speed and low speed switching lever (L)
Between the switching lever (L) and the speed increase switching mechanism (B),
Acceleration switching mechanism regardless of the lever position of the switching lever (L)
(B) Forced switching link for controlling on / off of speed-up switching operation
The mechanism (M) is installed, and the forced switching link mechanism (M) has a speed-up switching mechanism.
(B) Incoming position where the speed increase switching operation is possible and the speed increase switching operation
Forced switching lever that can be selectively switched to the off position
(L ') are interlockingly connected, and the switching lever (L') is in the on position, and the high / low speed switching lever is
-Speed increase switching mechanism (B) only when (L) is on the low speed side
The speed-up operation and the high / low speed switching lever.
Even when (L) is located on the low speed side, the forced switching lever is
-(L ') to the off position to increase the speed changeover mechanism.
(B) is configured to be able to forcibly release the acceleration, and further, the forced switching link mechanism (M) has a detection means (88) for detecting the entry position of the forced switching lever (L '). , The alarm means (87) that operates in conjunction with the detection means (88)
A forced switching link mechanism in a front-wheel steering vehicle, comprising a speed-increasing switching mechanism.