JPH04356232A - Front wheel steering vehicle equipped with acceleration change-over mechanism - Google Patents

Abstract

PURPOSE:To provide a sure operation responsive to a hangle operation by connecting an operating mechanism of an acceleration change-over mechanism changed over to a condition transmitting power to a transmission system for front wheels with drive speed higher than rear wheel drive speed to a pitman arm support shaft of a steering mechanism through a cam mechanism. CONSTITUTION:Power of an engine on a tractor is transmitted to rear wheels through main and sub-speed change gears 5, 6 and rear wheel differential and to front wheels from the sub-speed change gear 6 through a front wheel drive shaft 14, acceleration change-over mechanism B and front wheel differential 15. Then, a triangular press roller mounting plate 52 is fixed to a shift sleeve 51 fitted on a pitman support shaft 50 of a steering mechanism. While a press roller 53 is journalled by the plate 52, a triangular acceleration change-over operating plate 54 opposed to the press roller 53 is fitted on a pitman support shaft 50. The acceleration change-over mechanism B can be changed over to the acceleration condition by the rotation of the pitman arm support shaft 50 through a cam mechanism F consisting of these press roller 53 and acceleration change-over operating plate 54.

Description

[Detailed description of the invention]

0001

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

0002

[Prior Art] Conventionally, for the purpose of improving the workability of tractors and the like in the field, especially reducing the turning radius when turning, an operating mechanism for operating a speed increasing switching mechanism has been installed on the front differential shaft. It is installed in the knuckle arm located in the center of the steering wheel, and when the knuckle arm reaches a certain rotation angle or more in conjunction with the steering operation of the steering wheel, the speed increase switching mechanism is activated via the operation mechanism to increase the desired speed. Front wheel steered vehicles have been developed that can impart speed to the front wheels.

0003

[Problems to be Solved by the Invention] However, in such conventional front-wheel steering vehicles, the operating mechanism is not directly connected to the steering wheel, so it is insensitive to steering wheel operations, and the speed doubling mechanism must be operated reliably. The problem was that it could not be done.

[0004] Furthermore, the knuckle arm portion where the operating mechanism is provided is a place where dirt, grass, etc. are very likely to get entangled.
This has led to accidents such as the operating mechanism being damaged or becoming inoperable.

SUMMARY OF THE INVENTION An object of the present invention is to provide a front wheel steering vehicle equipped with a speed increase switching mechanism capable of solving the above problems.

[0006]

[Means for Solving the Problems] The present invention provides a transmission system for front wheels that can be freely steered, with a standard drive state in which power is transmitted at a drive speed that is approximately equal to the rear wheel drive speed, and a drive state that is greater than the rear wheel drive speed. A front-wheel steering vehicle equipped with a mechanically operated speed-up switching mechanism that can switch between a speed-up drive state in which transmission is performed by speed, and in which the speed-up switching mechanism is switched to the speed-up drive state by steering operation of the front wheels beyond a set angle. This invention relates to a front wheel steering vehicle equipped with a speed increasing switching mechanism, characterized in that the operating mechanism of the speed increasing switching mechanism and the pitman arm support shaft of the steering mechanism are connected via a cam mechanism so that the speed increasing switching mechanism can be switched to It is something.

[0007]

[Function] With the above-described configuration, the present invention has the following functions and effects.

■Since the operating mechanism of the speed increase switching mechanism is connected to the pitman arm support shaft of the steering mechanism via a cam mechanism, the distance between the handle in the steering mechanism and the speed increase change mechanism is short. This makes it possible to obtain a reliable operating range in response to steering wheel operations.

[0009] Since the operating mechanism of the speed increase switching mechanism is configured by being connected to the pitman arm support shaft of the steering mechanism via a cam mechanism, the operating mechanism can be placed at a position separated from the knuckle arm. It is possible to prevent dirt and grass from getting entangled with the operating mechanism as much as possible, and accidents such as breakdowns and inoperability can be reliably prevented.

0010

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained in detail below based on examples shown in the accompanying drawings.

In FIG. 1, A is a tractor, and the tractor A has a front wheel and a rear wheel 2 attached to its front and rear parts, respectively. It is driven by a drive mechanism that

That is, in the drive system diagram of the drive mechanism shown in FIG. 2, 3 is the engine, 4 is the main clutch, 5 is the main transmission, 6 is the auxiliary transmission, and 7 is the rear wheel differential device. A differential yoke shaft 8 of No. 7 is operatively connected to each rear wheel 2 via a final reduction gear 9. In addition, 10 is each differential yoke shaft 8
The rear wheel brake is installed at the outer end of the vehicle.

Note that in the above configuration, the main transmission 5,
The sub-transmission device 6 is built into the transmission case.

Reference numeral 11 indicates a front wheel drive system, and the front wheel drive system 11 includes a gear train 12 and a universal joint 1 in an auxiliary transmission 6.
The front wheel drive shaft 14 is connected to the front wheel drive shaft 1 through the front wheel drive shaft 1
Each differential yoke shaft 16 of the front wheel differential device 15 is connected to the front wheels 1 via a gear train 17, and the front wheels 1 can be steered around the king pin. It has become.

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

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

In the figure, 21 has a built-in front wheel differential device 15;
The front axle case 21 is supported by a case swinging support part 21a so as to be swingable from side to side. The cylindrical casing 20 is supported at its midpoint by a bearing 24 whose upper end is 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 cylindrical casing 20 is arranged so as not to come into contact with these.

The cylindrical casing 20 also has a bevel gear 27 therein extending from the front wheel differential device 15 toward the front wheel drive shaft 14 and meshing with the gear train of the front wheel differential device 15.
A pinion shaft 29 is provided at the front end, and a universal joint 1 is provided at the rear end.
3, the front wheel drive shaft 14 and the speed increasing switching mechanism input shaft 30 which are interlocked and connected are arranged in series.

Further, reference numeral 31 denotes an intermediate rotating cylinder that is attached concentrically and relatively rotatably over substantially the entire length of the pinion shaft 29, and the intermediate rotating cylinder 31 has a spline on the rear end side, which is slidable in the axial direction. A sliding cam body 32 is attached to rotate integrally with the intermediate rotating cylinder 31, and the sliding cam body 32 is connected to the rear end side of the speed increasing switching mechanism input shaft 30 via a spline via a dog clutch 33. It is removably engaged with the connected flange 34.

Note that the sliding cam body 32 is connected to the yoke support shaft 35.
It is moved in the axial direction by a swinging fork 36 which is swingably supported by the swinging fork 36.
is interlocked and connected by a steering mechanism D and an operating mechanism C, which will be described later, and its rocking causes the dog clutch 33 to
In addition to being able to engage and disengage, the multi-disc clutch 37 described below can be operated.

That is, as shown in FIG.
The multi-disc clutch 37 compresses the spring 38 by the axial movement of the sliding cam body 32 caused by the swinging of the swinging yoke 36, causing the intermediate rotating cylinder 31 to become cylindrical. It can be fixed to the casing 20 to stop its rotation.

Reference numeral 40 denotes a speed increasing differential mechanism provided at the front end of the pinion shaft 29.
Attach the pinion shaft 2 to the inner surface of the rotating housing 41.
A bevel gear 42 having an axis in a direction perpendicular to the axis of 9.
The front and rear surfaces of the bevel gear 42 are respectively engaged with a bevel gear 43 fixed to the rear end of the pinion shaft 29 and a bevel gear 44 integrally formed at the rear end of the intermediate rotating cylinder 31.

Next, a speed increasing switching mechanism B having the above configuration is provided.
The effect of this will be explained.

When the engine 3 is started and the main clutch 4 is connected, the power of the engine 3 is transmitted through the main clutch 4, the main transmission 5, the auxiliary transmission 6, the rear wheel differential 7 and the final reduction gear 9. The signal is transmitted to the rear wheel 2.

On the other hand, the front wheel drive shaft 14,
Each front wheel 1 via the speed increase switching mechanism B and the front wheel differential device 15
Therefore, the tractor A runs with these four wheels, front wheel 1 and rear wheel 2, as driving wheels. Therefore, when driving straight, a standard drive state is established in which front wheels 1 and rear wheels 2 are driven at the same speed, but this can be explained with reference to the drive system diagram shown in Fig. 2 as follows. .

That is, the steering mechanism D to be described later is the swinging fork 3.
6, the multi-plate clutch 37 is not operating, and therefore the intermediate rotating cylinder 31 is not fixed to the cylindrical casing 20. On the other hand, the speed increase switching mechanism input shaft 30 is integrally connected to the intermediate rotating cylinder 31 by the dog clutch 33.

Therefore, the rotation of the front wheel drive shaft 14 is transmitted from the speed increase switching mechanism input shaft 30 to the rotating housing 41 and the intermediate rotating cylinder 31, and then to the bevel gear 42, the bevel gear 43, the pinion shaft 29, the bevel gear 44,
The intermediate rotary cylinder 31 is rotated at the same speed as the front wheel drive shaft 14, and then the power is transmitted to the front wheels 1 via the front wheel differential device 15 and the front wheel yoke shaft 16.

On the other hand, when the steering mechanism D is steered to the extent that the swinging fork 36 is operated, the swinging fork 36 presses the multi-disc clutch 37 via the sliding cam body 32, thereby causing the intermediate rotation cylinder to 31 is fixed to the cylindrical casing 20, and by disengaging the dog clutch 33, the connection between the speed increasing switching mechanism input shaft 30 and the intermediate rotating cylinder 31 is released.

Therefore, the rotation of the front wheel drive shaft 14 is transmitted from the speed increase switching mechanism input shaft 30 to the rotating housing 41, but the power transmission path from the bevel gear 42 to the bevel gear 43, the pinion shaft 29, and the front axle case 21 is This and the relative rotation with the rotating housing 41 form a differential gear mechanism, and the pinion shaft 29 and bevel gear 27 rotate at twice the speed of the front wheel drive shaft 14, and then, An increased speed driving state is entered in which the speed is transmitted to the front wheels 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 slipping.

In the above-mentioned speed increasing operation, since the speed increasing switching mechanism B according to this embodiment is equipped with a speed increasing differential mechanism 40 consisting of a multi-disc clutch 37 and an operating gear device, the speed increasing effect is gradually reduced. Since the speed can be increased in stages and the multi-disc clutch 37 absorbs the load, the field will not be damaged.

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

In FIGS. 5 to 7, reference numeral 50 denotes a pitman arm fulcrum shaft rotatably mounted horizontally on the clutch casing 49, and the pitman arm fulcrum shaft 50 is disposed approximately directly below a steering mechanism D, which will be described later. ing.

[0034] Then, the Pitman arm fulcrum shaft 5
0 to the aforementioned swinging hawk 3 via the path described below.
It is interlocked and connected to a yoke support shaft 35 to which 5 is fixed. That is, as shown in FIGS. 6 and 7, the pitman arm fulcrum shaft 50 is movable in the axial direction;
A moving sleeve 51 is attached that rotates integrally with the
The movable sleeve 51 has a pressure roller mounting plate 52 fixed to one end thereof in the form of an isosceles triangle with its apex facing forward.

[0035] Upper and lower pressing rollers 53 are rotatably supported on the side surfaces of the rear upper and lower ends of the pressing roller mounting plate 52.

Further, in FIGS. 6 and 7, reference numeral 54 denotes a speed increaser having a pitman arm fulcrum shaft 50 slidably inserted into a rectangular notch opening 55 provided at the rear of the pressure roller 53 at a position corresponding to the pressure roller 53. This is a switching operation board. The speed increase switching operation plate 54 also includes the pressure roller mounting plate 5
2, it has an isosceles triangular shape with the apex facing forward.

The pressure roller 53 and the speed increase switching operation plate 54 constitute a cam mechanism F, and the cam mechanism F is configured so that the pressure roller 53 moves to the position shown by the solid line as the movable sleeve 51 moves. In this state, when the pitman arm fulcrum shaft 50 is rotated by the steering mechanism D described later, the pressure rollers 53, 53 swing together with the pressure roller mounting plate 52, and when they come into contact with and press the speed increase switching operation plate 54, the speed is increased. The switching operation plate 54 is configured to move forward.

Further, 56 has a base end connected to a speed increasing switching operation plate 54.
The connecting rod 56 is fixed to the front part of the yoke lever 57 and has its tip extending toward the speed increasing switching mechanism B.
is connected to the tip of the

With this configuration, the speed increase switching operation plate 54
The forward movement of the swing lever 57 and the yoke support shaft 35 and swing yoke 36 that are integral with the swing lever 57 swing, and this swing causes the multi-disc clutch 37 to engage and the speed increase switching mechanism B to increase the speed. This will allow you to switch to speed mode.

A shock absorbing mechanism E is attached to the connecting rod 56 to prevent damage to the speed increasing switching mechanism B in the event that the speed increasing switching operation plate 54 side fails.

[0041] In this embodiment, such a shock absorbing mechanism E is as follows:
As shown in FIGS. 6 and 7, a 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 fixed to the middle of the connecting rod 56. And the same stopper nut 61 and piece 6
0, a sleeve 62 is attached concentrically to the connecting rod 56 so as to be movable in the axial direction.
A contact tube 64 is provided at the tip of the sleeve 62 and is biased forward by a spring 63 disposed inside the sleeve 62.
It is constructed by pressing the piece 60 with the tip of the piece 4 and making the swinging lever 57 swingable.

Next, the configuration of the steering mechanism D for operating the operating mechanism C will be explained with reference to FIGS. 8 to 10.

In the figure, reference numeral 70 denotes a steering rod installed in an inclined state in the driver's seat, and the steering rod 70 has a steering handle 71 attached to its upper end, and a gearbox whose base end is attached to a gearbox stay 72. It is connected to the input shaft of 73.

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 to the output shaft of the gear box 73.
4 is connected by a drag rod 76 to a swing lever 75 fixed to a pitman arm support shaft 50 disposed substantially directly below the steering handle 71.

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

Further, the steering arms 78, 78 attached to the left and right front wheels 1 are connected by a tie rod 80.

With this configuration, when the steering handle 71 is rotated, the drag rod 76, pitman arm 77, drag rod 79, steering arm 78,
The left and right wheels 1, 1 can be rotated via the tie rod 80.

In the above steering action, the pitman arm support shaft 50 also inevitably rotates, and this rotation activates the operating mechanism C as described above.
The speed increase switching mechanism B will be activated.

In addition to the above configuration, this embodiment is also characterized by a configuration in which the speed increasing switching mechanism B is not operated during so-called high/low speed switching.

This configuration will be explained below with reference to FIGS. 6 and 7.

That is, in FIGS. 6 and 7, 90, 90
are regulation plates mounted on the movable sleeve 51 at intervals in the axial direction.

[0052] The front end of a swing lever 92 whose center portion is swingably supported by a support shaft 91 is inserted between the regulation plates 90, 90. The other end of a push-pull type inner wire 93 is connected to the rear end, and one end of the push-pull type inner wire 93 is connected to a high/low speed switching lever L disposed at the same position as the above-mentioned steering mechanism D.

Then, in conjunction with the switching operation of the high/low speed switching lever L (see FIG. 1) to the high speed side, the swinging lever 92 swings via the inner wire 93, and by the same swinging, the movable sleeve 51 is moved from the solid line position to the imaginary line position, and along with the same movement, the pressing roller 53 is also moved from the engagement position (solid line position) with the speed increase switching operation plate 54 to the disengagement position (imaginary line position). become.

Therefore, at high speeds, even if the pitman arm support shaft 50 rotates, the pressing roller 53 is in a non-engaging position with respect to the speed increase switching operation plate 54, so that the operation plate 5
You cannot move it forward by pressing 4, so
The speed increase switching mechanism B does not work, and the front wheels 1 do not accidentally turn at double speed when turning on the road, thereby ensuring safe driving.

Note that when the high/low speed switching lever L is on the low speed side, such as during plowing work, the moving sleeve 51 and the pressure roller 53 are both moved to the position shown by the solid line, and the pressure roller 53 is switched to increase speed. Since it is located at a position corresponding to the operation plate 54, when the steering handle 71 is turned, the pressure roller 53 also swings in conjunction with this, and can press the operation plate 54 and move. It can be activated. Therefore, the front wheels 1 can be turned at double speed, and sharp turns can be made.

With the configuration and operation described above, the present invention has the following effects.

■Since the operating mechanism C of the speed increase switching mechanism B is configured by being connected to the pitman arm support shaft 50 connected to the handle gear box 72 provided below the steering handle 71, the steering handle 71 and the speed increase The distance from the switching mechanism B is shortened, and a reliable operation range can be obtained in response to the operation of the steering handle 71.

■The operation mechanism C of the speed increase switching mechanism B is constructed by connecting it to the pitman arm support shaft 50 connected to the handle gear box 73 provided below the steering handle 71. The operating mechanism C can be placed at a position separated from the
It is possible to prevent dirt and grass from getting entangled with the operating mechanism C as much as possible,
Accidents such as breakdowns and inoperability can be reliably prevented.

[Brief explanation of drawings]

FIG. 1 is a side view of a front wheel steering vehicle (tractor) equipped with a speed increase switching mechanism according to the present invention.

FIG. 2 is a diagram of the drive system.

FIG. 3 is an explanatory diagram of the arrangement of a speed increase switching mechanism.

FIG. 4 is an enlarged structural explanatory diagram of the speed increase switching mechanism.

FIG. 5 is a structural explanatory diagram of the operating mechanism.

FIG. 6 is an enlarged explanatory diagram of the main part.

FIG. 7 is an enlarged explanatory diagram of the same main part.

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 main parts.

[Explanation of symbols]

A Tractor B Speed increase switching mechanism C Operation mechanism D Steering mechanism 1 Front wheel 2 Rear wheel 14 Front wheel drive shaft 21 Front axle case 50 Pitman arm support shaft 73 Handle gear box

Claims (1)

[Claims] Claim 1: The transmission system for the front wheels (1), which can be freely steered, has a standard drive state in which power is transmitted at a drive speed approximately equal to the rear wheel drive speed, and an increased speed in which power is transmitted at a drive speed greater than the rear wheel drive speed. A front wheel steering vehicle is equipped with a mechanically operated speed increasing switching mechanism (B) that can be switched between a driving state and a driving state.
1) The speed increase switching mechanism (
The operating mechanism (C) of the speed increase switching mechanism (B) and the pitman arm support shaft (50) of the steering mechanism (D) are connected to the cam mechanism (F) so that the speed increase switching mechanism (B) is switched to the speed increase drive side.
A front wheel steering vehicle equipped with a speed increasing switching mechanism, characterized in that the speed increasing switching mechanism is connected via a.