JPH05221336A - Compulsory vehicle changeover link mechanism in front wheel steering mechanism vehicle equipped with speed-increase changeover mechanism - Google Patents

Abstract

PURPOSE:To eliminate the danger of falling down even on a slant, etc., by coupling the speed- increase changeover mechanism provided on the side of a front wheel to a high-low speed changeover lever thereby increasing the speed of the speed-increase changeover mechanism only at operation of changeover into low speed, and providing a compulsory changeover link mechanism between these, thereby canceling the speed increase of the speed-increase changeover mechanism also at changeover into low speed. CONSTITUTION:The speed of a speed-increase changeover mechanism B is increased only at low-speed changeover operation of a lever L by coupling the speed-increase changeover mechanism B to a high-low speed changeover lever L. Furthermore, the speed increase of the speed-increase changeover mechanism B is compulsorily canceled also at changeover into low speed by the high-low speed changeover lever L by providing a compulsory changeover link mechanism M between the lever L and the speed-increase changeover mechanism B. That is, the compulsory link mechanism M comprises the first link mechanism 81 coupled to the high-low speed changeover lever L, the second link mechanism 82 coupled to a changeover wire 93, and a compulsorily changeover lever L' coupled to this. And, if the compulsory changeover lever L' is cut off in advance, the speed-increase changeover mechanism B is kept off even if the high-low speed changeover lever L is changed over to low speed side or high speed side.

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 increasing switching mechanism which is configured to be capable of driving front wheels and rear wheels, and which can switch between constant speed and speed increasing 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 speeds up 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 increased in speed 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 by a low speed switching operation, there is a risk that the tractor will fall due to a sudden turn.

[0005]

Therefore, in the present invention, the front wheel and the rear wheel are configured to be drivable, and the front wheel side is provided with a front wheel and a rear wheel that can be switched between constant speed and speed increase freely. The speed changeover mechanism is installed, and the speed increase changeover mechanism is interlocked with the high / low speed changeover lever so that the speedup changeover mechanism operates to increase the speed only when the lever is operated at a low speed. A speed-up switching mechanism is provided between the speed-switching mechanism and the speed-up switching mechanism so that the speed-up switching mechanism can be forcibly released from the speed-up switching mechanism even when low-speed switching is performed by the high-low speed switching lever. It is intended to provide a compulsory switching link mechanism in a front-wheel steering vehicle.

Further, according to the present invention, a force switching lever for operating the force switching link mechanism is connected to the force switching link mechanism, and a detecting means for detecting an entering position of the force switching lever and a detecting means therefor. It is also characterized in that the alarm means that operates in conjunction with is connected in series.

[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. 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. A 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 through a sub transmission 6 gear train 12 and a universal joint 13 and the front wheel drive shaft 14. The front wheel diff device 15 is connected to each diff yoke shaft 16 of the front wheel diff device 15 via a gear train 17 so that the front wheel 1 can be steered 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 has a front wheel differential device 15 built-in and is swingably supported left and right by a case swing support portion 21a. The front axle case 21 has a rear portion, The base end of a tubular casing 20 extending rearward is provided so as to project.
The middle portion of 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 a gear train of the front wheel differential device 15 and which is engaged with a gear train of the front wheel differential device 15, from the front wheel differential device 15 to the front wheel drive shaft 14 inside. A speed increasing mechanism input shaft 30 having a rear end interlockingly connected to the 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 mounted 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 sliding cam body 32.
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 and the multi-plate clutch 37 described below can be operated by swinging the operating mechanism C.

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 cylindrical 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 the 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 engaged, 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 explanatory diagram shown in FIG.

That is, the steering mechanism D, which will be described later, has a swing hawk 36.
When the steering is not performed to the extent that the valve is operated, the multi-plate clutch 37 is not operated, 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, 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 is rotated. 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 that it rotates at twice the speed of the front wheel drive shaft 14, and then is 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 with a small turning radius without slippage.

In the speed-increasing operation, the speed-increasing switching mechanism B according to this embodiment is provided with 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 increasing switching mechanism B in conjunction with the steering operation of the steering mechanism D 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 moving 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 the apex facing forward.

A vertical pressing roller 53 is rotatably supported on the side surfaces of the upper and lower ends of the rear part 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 increasing / 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 shown 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 is 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 the 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.
A shock absorbing mechanism E is attached to prevent the speed increasing switching mechanism B from being destroyed when the 54 side fails.

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 piece 60 is pressed by the tip of the contact cylinder 64 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 that is provided in a tilted 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 gearbox 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 such a structure, when the steering wheel 71 is rotated, the left and right wheels 1, 1 can be turned via the drag rod 76, the pitman arm 77, the drag rod 79, the steering arm 78, and the tie rod 80.

In the steering action, 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 construction, the gist of the present invention is to connect the speed increasing switching mechanism B to the high / low speed switching lever L in an interlocking manner so that the speed increasing switching mechanism B operates only when the low speed switching operation of the lever L is performed. In addition to the above configuration, the forced switching link mechanism M is provided between the lever 1 and the speed increasing switching mechanism B, and the speed increasing release of the speed increasing switching mechanism B is forcibly released even when the high speed switching lever L switches the low speed. The configuration will be described in detail below with reference to FIGS. 6, 7, and 11 to 13.

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 pivotally supported by a support shaft 91 in a central portion is inserted, while a rear end of the swing lever 92 has one end arranged on the left side of a seat 95. 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 shows the moving sleeve 51 and the pressing roller 53 in solid lines. When the steering handle 71 is turned, the pressing roller 53 also swings in conjunction with this because the pressing roller 53 moves to the position and is in a position corresponding to the speed increase switching operation plate 54, and the operating plate 54 is pressed. It is configured such that the speed increasing switching mechanism B can be operated (hereinafter, this state is referred to as an “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.

A 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 switching 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 along with the movement, the vertical pressing roller 53 also engages with the speed increase switching operation plate 54 (solid line position)
To the non-engagement position (virtual line position) (hereinafter, this state is referred to as the “off” state).

Therefore, at a high speed, even if the Pippmann 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 turns in the 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 forced operation link mechanism M includes a first link mechanism 81 interlockingly connected to the high / low speed switching lever L, a second link mechanism 82 directly interlockingly connected to the switching wire 93, and a second linking mechanism 82.
It comprises a forced switching lever L'interlockingly connected to the link mechanism 82.

The first and second link mechanisms 81 and 82 are
Lever support shaft 83 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.

Moreover, each link mechanism 81, 82 has its base end pivotally supported by the lever support shaft 83, and its base end supported by the auxiliary transmission shifter shaft 84, and the tip ends of the first and second telescopic links 81a, 82a. 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 in the middle 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 locking portion 81e.
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 operated so as to be bent in the middle, and the second arm 82b 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 faster than the rear wheel 2 when the vehicle body turns, a sharp turn is possible.

When the lever L'is turned downward, the second telescopic link 82a is extended in the straight direction, and the second arm 82b is turned rearward, which is the opposite of the above. 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 this 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 forced 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 / contraction operation of the first link 81a and the first link 81a are performed.
The forward / backward rotation operation of the arm 81b is not interlocked 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 means such as an alarm lamp or 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 lights up.

As described above, 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, and the operational safety is ensured. It is good to be able to keep.

[0069]

According to the present invention, if the forced switching link mechanism is operated so that the speed increasing switching mechanism speeds up only during low speed switching, the high speed / low speed switching lever is operated to perform low speed switching. When the turning operation is performed at the same time, the speed increase switching mechanism increases the speed and the machine can be turned rapidly.

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

Further, a forcible switching lever for operating the above forcible switching link mechanism is provided, and detection means for detecting the entry position of the forcible switching lever and alarm means for operating in conjunction with the detection means are also provided in series. Since the alarm means is configured to operate when the forced switching lever is in the "ON" state, the operator can be alerted by turning on an alarm lamp, which is the alarm means. It is safer and various work 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 operation 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 a forced switching link mechanism.

FIG. 12 is a development explanatory view of the link mechanism.

13 is a cross-sectional view taken along 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,
On the front wheel 1 side, a front wheel 1 and a rear wheel 2 are provided with a speed increasing switching mechanism B capable of switching between constant speed and speed increasing.
Is connected to the high / low speed switching lever L so that the speed increasing switching mechanism B is operated only when the low speed switching operation of the lever L is performed, and the force between the lever L and the speed increasing switching mechanism B is forced. Forced in a front-wheel steering vehicle equipped with a speed-up switching mechanism that allows a speed-up switching mechanism B to be forcibly released even during low-speed switching by a high-low speed switching lever L via a switching link mechanism M. Switching link mechanism. 2. The forcible switching link mechanism M is connected with a forcible switching lever L'for operating the forcible switching link mechanism M, and a detecting means 88 for detecting the entry position of the forcible switching lever L ', A forced switching link mechanism in a front-wheel steering vehicle comprising a speed-up switching mechanism according to claim 1, wherein an alarm means 87 which operates in conjunction with the detecting means 88 is connected.