JPS63154427A - Front wheel speed change operating structure for working vehicle - Google Patents

Abstract

PURPOSE:To reliably hold the engaged state of a claw type clutch without making the operation of a steering handle heavy by applying a holding function to a transfer lever for a front wheel transmission and the steering handle and using the transfer lever as a stopper. CONSTITUTION:When a transfer lever 34 is operated around a lateral axis P4, the lower end of an operating arm 35 is brought into contact with the first contact section of a transfer member 24. When the transfer lever 34 is operated around a longitudinal axis P5 to be located at the position of 4WD-II, the operating arm 35 is operated around a longitudinal axis P3, and the transfer member 24 is operated to the off position. The transfer member 24 is energized to the engaged side of a claw clutch, i.e., the standard drive side by a spring 31, and the transfer lever 34 is coupled and held by the recess 39a of a lever guide 39. Accordingly, the transfer member 24 is reliably held at the standard drive side, i.e., the engaged state of the claw type clutch.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention applies to a four-wheel drive type work vehicle, which has 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 standard drive state in which power is transmitted at a drive speed that is approximately equal to the rear wheel drive speed, and a state in which power is transmitted at a drive speed that is greater than the rear wheel drive speed. The present invention relates to a front wheel shift operation structure for a type of work vehicle in which a front wheel transmission system is provided in a transmission system for the front wheels to switch to an increased speed drive state in which transmission is performed at a drive speed.

[Conventional technology]

By providing a front wheel transmission as described above and configuring the front wheel transmission to be operated to the speed increasing drive side in conjunction with the operation of the steering wheel when turning, the work area will not be disturbed, and
Although it is possible to easily make sharp turns even on soft ground, the front wheel transmission is generally not operated frequently to increase the speed.
Normally, the vehicle runs in four-wheel drive on the standard drive side or in two-wheel drive with only the rear wheels.

Therefore, the clutch on the standard drive side of the front wheel transmission is designed to be a durable biting type clutch that ensures power transmission, and the biting part of the biting type clutch is biased toward the biting side by a spring or the like. structure is proposed.

[Problem that the invention seeks to solve]

The purpose of biasing the articulating clutch toward the occlusal side is to prevent the articulating parts from separating from each other due to vibrations while driving, resulting in the clutch being disengaged. In order to reliably maintain this condition, it is necessary to further strengthen the biasing force of the spring or the like.

However, if the biting clutch has a strong biasing force towards the biting side, even if you try to use the steering wheel to operate the front wheel transmission to the speed increasing drive side during a turn, the biasing force will act as resistance, making it difficult to operate the steering wheel. Since it becomes heavy, it is not preferable from the viewpoint of maneuverability.

Here, the present invention focuses on the above-mentioned points, and an object of the present invention is to make it possible to reliably maintain the engaged state of the dog clutch without causing problems such as making the operation of the control handle difficult.

[Means for solving problems]

A feature of the present invention is that, in the above-mentioned front wheel transmission structure for a work vehicle, the front wheel transmission is biased toward the standard drive side, and the switching lever connected to the switching member that performs the switching operation can be held in the uncoupled position. It is configured to contact and prevent the shifting of the bite type clutch to the disengaged side in the disengaged state through the switching lever and the switching member, and its operation and effects are as follows. That's right.

[For production]

With the configuration described above, the switching member for the front wheel transmission can be operated even if the engaging portion of the engaging portion clutch is about to shift to the separating side against the urging force that urges the front wheel transmission toward the standard drive side. If the switching lever is held in the disengaged position, the movement of the occlusal portion toward the separation side is prevented by the contact between the switching lever and the switching member via the switching member.

〔Effect of the invention〕

As described above, the switching lever that switches the front wheel transmission and the steering wheel between the linked and disengaged states has been slightly modified and a holding function in the disengaged position has been added, and the switching lever can be used as a so-called stopper. This makes it possible to prevent the engaging portion of the engaging clutch from shifting toward the separating side without particularly increasing the urging force that urges the front wheel transmission toward the standard drive side.

As a result, even when the front wheel transmission and the steering wheel are linked, the operation of the steering wheel does not become particularly difficult.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS A four-wheel drive agricultural tractor, which is one embodiment of the present invention, will be described below with reference to the drawings.

As shown in Figure 10, a pair of left and right front wheels (1
a), (1b) and the rear wheels (2a), (2b), and a lift arm (3) that connects various working devices to the rear of the machine so that they can be raised and lowered; and a P that transmits power to the working devices. - A four-wheel drive agricultural tractor is constructed by providing a TO shaft (4).

The front wheel (1a) is located at the bottom of the mission case (5) at the rear of the aircraft.
A front wheel transmission (6) is provided for the rear wheels (2a), (1b), and to explain this configuration in detail, as shown in FIGS. ) for the output gear (7) that receives power from
A first drive gear (8) fixed to the transmission shaft (10) meshes with the transmission shaft (10), and a second drive gear (11) is fixed to the other end of the transmission shaft (10). The front export force shaft (
14) are arranged in parallel, and the first and second drive gears (
8), (11) and the first and second driven gears (9), (
13) is loosely fitted onto the front export force shaft (14).

A sleeve (15) is fixed between the first and second driven gears (9L (13)), and a shift member (16) is spline-fitted to the sleeve (15).

An engagement type clutch (18) is configured between the shift member (16) and the first driven gear (9), and a multi-plate friction clutch is configured between the shift member (16) and the second driven gear (13). (12). The shift member (16
) to engage the first driven gear (9), the front wheels (1a), (1b) and the rear wheels (2a),
(2b) In the standard drive state where the drive speeds are approximately equal, power is transmitted from the front export force shaft (14) to the front wheel differential mechanism (19), and the shift member (16) is slid in the opposite direction. ), when the friction clutch (12) is pressed in, the front wheels (1a) and (1b) are driven faster than the rear wheels (2a) and (2b), and the power is transferred to the front wheel differential mechanism. (19).

Next, to explain in detail the linkage structure between the front wheel transmission (6) and the control handle (32), as shown in FIGS. 1 and 2, the shifter support shaft (2) is
0) are arranged in parallel, and a shifter (17) for slidingly operating the shift member (16) is connected to a shifter support shaft (2).
0) is slidably fitted on the outside. The operating shaft (23) is located below the front export force shaft (14) in a direction perpendicular to this axis (P2).
) is rotatably supported around the operating shaft (23).
An operating arm (25) provided at one end of the operating arm (25) and a operating handle (32) are mechanically interlocked and connected. The other end of this operating shaft (23) has a cylindrical shaft (23) with an operating arm (21).
22) is fitted loosely and externally, and Figure 1 shows the cylindrical shaft (22).
and the spline portion at the end of the operating shaft (23) (
23a), and the operating shaft (23), the cylindrical shaft (22), and the operating arm (21 ), the shift member (
16) is operated to push the friction clutch (12).

As shown in FIG. 8, the steering operation of the steering handle (32) is transmitted from the hydraulic power steering unit (26) to the knuckle arm (28) of the front wheel (1b) via the drag link (27). Ru. This knuckle arm (
As shown in FIGS. 8 and 9, a fan-shaped disc member (29) is attached to the disc member (29), and a friction locking mechanism (30) is provided for this disc member (29).

The friction locking mechanism (30) frictionally fixes the knuckle arm (28) when driving straight, etc., to the front wheel (1a).

(1b) prevents runout and ensures running stability.The Fj friction lock mechanism (30) is, as shown in Figure 9, a vertically slidable piston (4).
1) and the fixed part (37), the disc member (29
) and the piston (41) with the spring (42).
is biased towards the pinching side. When the steering handle (32) is held in a certain position facing I, the disk member (29) is frictionally held by the biasing force of the spring (42), but when you start operating the steering handle (32), A branch pressure saw from the power steering unit (26) is sent into the oil chamber (43) below the piston (41), the piston (41) is pushed down, and the frictional holding state is released.

Next, to explain in detail the structure for switching the front wheel transmission (6) and the control handle (32) into the linked and disengaged states, as shown in Figures 1 and 2, The support shaft (
36) is installed, and the operation arm (35), which has an inverted shape when viewed from the front, is swingably supported around the front and rear axis (P3) of the bracket (36a) provided on the lower surface of the support shaft (36).
One end of this operating arm (35) is connected to the switching member (24).
It is interlocked with the recess of the Further, a switching lever (34) is swingably mounted around the front and rear axis (P,) of the bracket (36b) provided on the upper surface of the support shaft (36), and a boss portion of the switching lever (34) The arm (34a) extending from the arm (34a) and one end of the operating arm (35) are connected via a rond (38).

In the state shown in FIGS. 1 and 5, the switching lever (34) is moved along the lever guide (39) shown in FIG.
) and turn the switching member (24) to (ON).
) position, that is, the switching member (24) is engaged with the cylinder 1 drawer (22) and the spline portion (23a) of the operating shaft (23), and the operating handle (32) and the front wheel transmission (6 ) in conjunction with each other to create a speed-up drive state when turning.

Next, when operating the switching lever (34) to the (4WD-II) position, first
34) around the horizontal axis (P4). Then, as shown in FIG. 6, the lower end of the operating arm (35) will come into contact with the first contact portion (24a) of the switching member (24). After that, the switching lever (34) is swung in a direction perpendicular to the previous operating direction, that is, around the longitudinal axis (P,).
When placed in the WD-II) position, the operating arm (35) is swung around the longitudinal axis (P3) and the switching member (24) is slid to the (OFF) position in FIG. It is. In this state, the front wheel transmission (6)
The connection between the control handle and the control handle (32) is cut off. ``And, the switching member (24) is biased by the spring (31) toward the engaging clutch (18) side, that is, the standard drive side, and furthermore, in the aforementioned position (4WD-n), the switching lever (34) is Recess (3) of lever guide (39)
9a), the switching member (24) is moved to the standard drive side, that is, the interlocking type, by the biasing force of the spring (31) and the abutting action of the lower end of the operating arm (35). This ensures that the clutch (18) is kept in the engaged state.

Then, when the switching lever (34) is operated to the (2WD) position, the operating arm (35) swings around the horizontal axis (P4), and the switching is performed with the control arm (35) disconnected from the control handle (32). The member (24) is operated to the (2WD) state shown in FIG. In this state, the shift member (16) of the front wheel transmission (6) is separated from the first driven gear (9) and is in a neutral position where it does not press the friction clutch (12), so that the front wheels (1a), (1b) Power is not transmitted to the

The mechanism (33) built into the switching member (24) is a ball-type detent mechanism that holds the switching member in the (4WD-1) and (4WD-II) positions.
) The mechanism (40) provided for the arm (36c) extending from the support shaft (36), etc. (4WD-1),
(4WD-old.

This is a ball-type detent mechanism that holds the vehicle in each position (2WD).

Incidentally, although reference numerals are written in the claims section for convenient comparison with the drawings, the present invention is not limited to the structure shown in the accompanying drawings.

[Brief explanation of the drawing]

The drawings show an embodiment of the front wheel transmission operation structure for a working vehicle according to the present invention, and FIG. 1 is a longitudinal sectional front view showing the front wheel transmission and its operation system, and FIG. 2 is a longitudinal sectional side view of the operation system of the front wheel transmission. Figure 3 is a view taken from the direction mm in Figure 2, Figure 4 is a vertical cross-sectional side view of the front wheel transmission, and Figure 5 shows the accelerated drive state when turning in four-wheel drive mode. FIG. 6 is a side view showing the state of the switching member and the operating arm when the vehicle is turned, and FIG. FIG. 8 is a schematic plan view showing the steering operation system for the front wheels; FIG. 9 is a longitudinal sectional front view of the friction lock mechanism; FIG. 10 is an agricultural tractor. FIG. (1a), (1b)...Front wheel, (6)...
...Front wheel transmission, (18)...Articulating clutch, (24)...Switching member, (32)...
... Control handle, (34) old switching lever.

Claims (1)

[Claims] The transmission system for the freely steerable front wheels (1a) and (1b) 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 drive state in which power is transmitted at a drive speed greater than the rear wheel drive speed. The standard drive side of the front wheel transmission (6) is configured as an engagement type clutch (18), and the front wheel transmission (6) and the steering wheel (32) are provided with a clutch type front wheel transmission (6) that switches between the two. The front wheels (
The front wheel transmission (6) is configured to be operated to the speed-increasing drive side by a steering operation greater than or equal to the set angle of 1a) and (1b), and further includes a front wheel transmission (6) and a steering handle (32).
A front wheel transmission operation structure for a working vehicle configured to be able to switch between a linked state and a disengaged state, the front wheel transmission (6
) to the standard drive side, and the switching lever (34) linked to the switching member (24) that performs the switching operation is configured to be able to be held in a disengaged position, so that the engaging type clutch is in the disengaged state. (18) A front wheel speed change operation structure for a work vehicle configured to prevent the shift to the turning side by abutment via a switching lever (34) and a switching member (24).