JPH0466332A - Four-wheel drive type working vehicle - Google Patents

Abstract

PURPOSE:To simplify structure by constituting a working vehicle such that connection operation of a shift fork to a shift shaft and slide operation of the shift fork to a neutral position with one operation member in obtaining 3 conditions of speed increase four-wheel drive condition, normal four-wheel condition and two-wheel drive condition. CONSTITUTION:A transmission system to front wheels steered freely is provided with a front wheel shifting device capable of carrying out switching freely in selection by slide operation of a shift member 14. A shift member 18 and front wheel steering systems 21-23 which support a shift fork 17 for the shift member 14 fitted thereto are interlocked and interconnected through an interlocking device 24. The shift member 14 or the shift fork 17 is energized to the side of the normal drive. Further a pin part 6 for interconnecting the shift fork 17 and the shift shaft 18. Furthermore, a single operation member 16 capable of carrying switching operation freely is provided over three positions; a speed increase four-wheel drive position 4WD-II to slide the pin member 6 to the connection position; a normal four-wheel drive position to slide the pin member 6 to the connection release position; and two-wheel drive position to operate the shift fork 17 to a neutral position between the normal drive side and the speed increase drive side.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a four-wheel drive type working vehicle such as an agricultural tractor.

[Conventional technology]

Agricultural tractors, which are one type of four-wheel-drive work vehicle, have a standard drive state in which power is transmitted at a drive speed that is approximately equal to the rear wheel drive speed, and an increased speed drive state in which power is transmitted at a drive speed that is greater than the rear wheel drive speed. In some cases, a front wheel transmission that can be selectively switched by sliding a shift member is installed in the transmission system for the front wheels that can be freely steered.
It is disclosed in the publication No.-14927.

With this structure, the standard four-wheel drive state is such that the front and rear wheels are always driven at the same speed regardless of when going straight or when turning.When going straight, the front and rear wheels are driven at the same speed, and the front wheels are steered from the straight-ahead position to a set angle or higher. Then, it is possible to switch between three states: an accelerated four-wheel drive state in which the front wheels are driven at a higher speed than the rear wheels, and a two-wheel drive state in which transmission to the front wheels is cut off and only the rear wheels are driven.

[Problem to be solved by the invention]

In the above-mentioned structure, in the accelerated four-wheel drive state, the operation of the front wheel steering mechanism is controlled by the shift fork ((22) of the above publication) via the cam member ((22) of the above publication) and the operating arm ((16) of the above publication). 17)) to slide the shift member of the front wheel transmission ((14) of the above-mentioned publication) to the speed-increasing drive side.

Therefore, in the above structure, by separating the cam member from the operating arm, the operation of the front wheel steering mechanism is not transmitted to the shift fork, and the standard four-wheel drive state is achieved. In this case, the shift member is held on the standard drive side by a spring ((20) of the above-mentioned publication) that biases the shift fork toward the standard drive side.

In addition, as mentioned above, by operating and holding the shift fork and shift member in the neutral position via the operating arm with the cam member separated from the operating arm, transmission to the front wheels is cut off, resulting in two-wheel drive using only the rear wheels. It shows the state.

As mentioned above, in the conventional structure, the member ((2)
6), (26a)), and an operating arm for operating the shift fork and shift member to the neutral position to bring about the two-wheel drive state ((16), (25) of the above-mentioned publication).
)), the structure was somewhat complicated, and there was room for improvement in terms of simplifying the structure.

The purpose of the present invention is to simplify the structure of a configuration that can obtain the above three states.

[Means to solve the problem]

A feature of the present invention is that a four-wheel-drive work vehicle equipped with the front wheel transmission as described above is configured as follows. In other words, [a] The shift shaft that externally supports the shift fork for the shift member and the front wheel steering mechanism are interlocked via the linkage mechanism, and the front wheel is steered by a predetermined angle or more from the straight-ahead position. , the shift shaft is configured to be slid to the speed-increasing drive side.

[B] Force the shift member or shift fork toward the standard drive side.

[C] A pin member is provided to connect the shift fork and the shift shaft so that the shift fork is slid integrally with the shift shaft toward the speed-increasing drive side, and the pin member is moved in a direction substantially orthogonal to the shift shaft. The shift fork is configured to be slidable to a disconnection position where the shift fork and the shift shaft are disconnected.

[2] A speed-up four-wheel drive position in which the pin member is slid to the coupling position, a standard four-wheel drive position in which the pin member is slid to the disengagement position, and a position in which the pin member is not slid to the disengagement position. , a single operating member is provided that can be freely switched over three positions, including a two-wheel drive position where the shift fork is pressed and pressed from the standard drive side to a neutral position between the standard drive side and the speed-up drive side; .

[For production]

With the configuration described above, when the operating member (16) is operated to the accelerated four-wheel drive position (4WD) as shown in FIG. 1, the operating member (16) moves the pin member (6) to the connecting position. Slide operation is performed.

In this state, when the front wheels are steered beyond the set angle from the straight-ahead position, the shift shaft (18) and shift fork (17) are integrally slid to the left in the paper, and the shift member that was operated to the standard drive side (14) is slid to the speed increasing drive side, and the front wheels or rear wheels are driven at a higher speed.

Next, increase four-wheel drive position (4WI)-II shown in Fig. 1.
') to the standard four-wheel drive position (4WD-I) as shown in Figure 2, the pin member (6) is slid to the disconnection position by the operation member (16). be done.

Therefore, even if the shift shaft (18) is operated to slide to the left in the paper in FIG.
7) is held on the standard drive side shown in FIG. 2 by the biasing force toward the standard drive side. This state is a standard four-wheel drive state in which the front and rear wheels are always driven at the same speed regardless of whether the vehicle is traveling straight or turning.

Next, when the operating member (16) is operated to the two-wheel drive position (2 ID) as shown in Fig. 3, the operating member (16)
pushes the shift fork (17) to a neutral position between the standard drive side and the speed-up drive side.

As a result, even if the shift shaft (18) is slid, the shift fork (I7) is held at the neutral position by the biasing force toward the standard drive side and the operating member (16). This state is a two-wheel drive state in which power to the front wheels is cut off and only the rear wheels are driven.

〔Effect of the invention〕

As described above, when the three states of accelerated four-wheel drive state, standard four-wheel drive state, and two-wheel drive state are brought out, it is necessary to connect the shift fork and the shift shaft, and to slide the shift fork to the neutral position. This can now be done with one operating member, making the structure simpler than the conventional structure.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings using a four-wheel drive agricultural tractor.

As shown in Figure 6, an engine (3) and a clutch (4) are installed at the front of the aircraft, supported by front wheels (1) and rear wheels (2).
A mission case (5) is mounted on the rear of the aircraft, making it a four-wheel drive agricultural tractor. Engine (3
) is transmitted from the clutch (4) to the hydrostatic continuously variable transmission and auxiliary transmission (not shown) in the transmission case (5), where the gears are changed and transmitted to the rear wheels (2). At the same time, the signal is transmitted to the front wheel transmission (7) shown in FIG. 1, and the gear is changed and transmitted to the front wheels (1).

The front wheel transmission (7) has a structure as shown in FIG. In other words, the standard output gear (I2) is attached to the transmission shaft (11).
A speed increasing output gear (13) is fixed, and power from an auxiliary transmission (not shown) is transmitted to the standard output gear (12) via a gear (35).

Then, a standard manual gear (
9) and the speed increasing input gear (1o) are fitted externally so as to be relatively rotatable, and the standard input gear (9), the standard output gear (12), the speed increasing input gear (10) and the speed increasing output gear (13) are engaged. are doing.

When the shift member (14), which is slidably attached to the output shaft (8) with a spline structure, is engaged with the standard input gear (9), the front and rear wheels (1) are connected.

(2) Power is transmitted while being driven at approximately the same speed.

Conversely, the friction clutch (15) configured between the speed increasing input gear (10) and the output shaft (8) is connected to the shift member (I4).
When pressed in, power is transmitted to the front wheels (1) or the rear wheels (2) in a state where they are driven at a higher speed.

Next, the structure of the operating system of the shift member (14) will be explained. As shown in FIGS. 1 and 4, the shift fork (17) for the shift member (14) is fitted onto a soft shaft (18) that is slidable in the axial direction, and
A spring (20) urges the shift fork (F) or the standard input gear (9) to the occlusal side (to the right in FIG. 1).

A pin member (6) is installed inside the shift fork (17) so as to be slidable in a direction substantially orthogonal to the shift shaft (18). The pin member (6) is provided with a pair of first and second notches (6a) and (6b), and the spring (19) is provided with a pair of first and second notches (6a) and (6b).
), the pin member (6) is urged downward in the plane of the paper. On the other hand, there is also a notch (
18a) is provided. In the state shown in FIGS. 1 and 4, the pin member (6) is pushed upwards in the paper by the operating member (16), and the protrusion (6c) of the pin member (6) ) into the notch (18a). Further, the pin (25) enters the second notch (6b) of the pin member (6) to prevent the pin member (6) from rotating.

As shown in FIG. 1, a cam plate (22) is fixed to a pitman arm (21) for steering the front wheel (1), and a pin (23a) of a swingable cam arm (23) is attached to the cam plate ( 22) is engaged in the cam hole (22a).

A wire (24) (corresponding to a linkage mechanism) is installed across the cam arm (23) and the shift shaft (18).

With the above structure, in the state shown in FIGS. 1 and 4 (the state in which the protrusion (6c) of the pin member (6) or the notch (18a) of the shift shaft (]8) is inserted), it is possible to operate the When the pitman arm (I6) is swung by the handle (26) beyond the set angle, that is, when the front wheel (1) is steered from the straight-ahead position to the set angle or above, the wire (24) is pulled. Ru. As a result, the protrusion (
6c) and the notch (18a) of the shift shaft (18), the shift shaft (18) and shift fork (17) were slid together and engaged with the standard input gear (9). The shift member (14) moves away from the standard input gear (9) and operates the friction clutch (15) in a suppressed manner.

As described above, when the front wheels (1) and (2) are driven at approximately the same speed and the front wheels (1) are steered beyond the set angle, the front wheels (1) will move faster than the rear wheels (2). The vehicle is also driven at high speed, and this state is an accelerated four-wheel drive state.

As shown in FIGS. 1 and 4, the operating member (16) has a fan shape in plan view, and the axial center (P) of the mission case (5).
l) Rotatably supported around the

From the accelerated four-wheel drive position (4WD-I[) shown in Fig. 1,
Move the operating member (16) to the standard four-wheel drive position (4) shown in Figure 2.
When the pin member (6) is rotated by the biasing force of the spring (19), the lower end of the pin member (6) is moved into the recessed part (WD-I) of the operating member (16). 1
Enter 6a).

This causes the protrusion (6c) of the pin member (6) to shift from the shift shaft (
At the same time, the first notch (6a) of the pin member (6) is removed from the notch (18a) of the shift shaft (18) downward in the plane of the paper.
Come to position 8). Therefore, in this state, the shift shaft (18
) is slid to the left of the page in Figure 2,
The shift fork (17) is moved to the second position by the biasing force of the spring (20).
It is held in the position shown in the figure. Regardless of whether this state is going straight or turning, the front and rear wheels (1).

(2) is the standard four-wheel drive state in which the vehicle is always driven at the same speed.

Next, move the operating member (16) to the two-wheel drive position (2) shown in FIG.
WD), the end of the operating member (16) (
16b) comes into contact with the protrusion (17a) of the shift fork (17), and the shift fork (17) and the shift member (14)
) is pushed into a neutral position between the standard input gear (9) and the friction clutch (15).

As a result, even if the shift shaft (]8) is slid, the shift fork (17) is held at the neutral position by the biasing force of the spring (20) and the operating member (16). This state is a two-wheel drive state in which power to the front wheels (1) is cut off and only the rear wheels (2) are driven.

Next, the relationship between the switching lever (27) for the operating member (16) in the front wheel transmission (7) and the sub-shift lever (28) for the sub-transmission (not shown) will be explained. As shown in Figure 5, the switching lever (27) and the sub-shift lever (28)
are supported to be able to swing independently of each other around the same axis (P2), and an operating arm (2) for the operating member (16) is supported.
9) and the switching lever (27).
A compression spring (31) is installed on this connecting rod (30).
) and a flexible structure of elongated holes (27a). Further, a linking rod (32) is installed across the elongated hole (29a) of the operating arm (29) and the sub-shift lever (28).

With the above configuration, when the switching lever (27) is operated to the accelerated four-wheel drive position (4WD-I [), the sub-shift is performed and the bar (2
8) If you operate the sub-shift lever (28) from the high-speed position (H) to the low-speed position (L), or conversely, to the high-speed position (I]),
Switch lever (27) or increase speed four-wheel drive position (4WD-II)
') to the standard four-wheel drive position (4WD-I).

It should be noted that the present invention is not limited to the structure shown in the accompanying drawings by adding reference numerals in the claims for convenient comparison with the drawings.

[Brief explanation of drawings]

The drawings show an embodiment of a four-wheel drive type work vehicle according to the present invention,
Fig. 1 is a longitudinal side view of the front wheel transmission in the accelerated four-wheel drive state, Fig. 2 is a longitudinal side view of the front wheel transmission in the standard four-wheel drive state, and Fig. 3 is a longitudinal cross-section of the front wheel transmission in the two-wheel drive state. 4 is a longitudinal sectional front view of the vicinity of the pin member in an accelerated four-wheel drive state, FIG. 5 is a side view of the vicinity of the switching lever and the sub-shift lever, and FIG. 6 is an overall side view of the agricultural tractor. (1)...Front wheel, (6)...Pin member, (7)...Front wheel transmission, (14)...
...Shift member, (16) ...... Operation member, (I
I)...Shift fork, (18)...
・Shift axis, (24)... Linkage mechanism, (4WD
-II)... Speed-up four-wheel drive position, (4WD-
1)...Standard four-wheel drive position, (2WD)...
...Two-wheel drive position.

Claims (1)

[Scope of Claims] A standard drive state in which power is transmitted at a drive speed substantially 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 can be changed by sliding the shift member (14). This is a four-wheel drive work vehicle in which a front wheel transmission (7) which can be selectively switched is provided in the transmission system to the front wheels (1) which can be freely steered. A four-wheel drive work vehicle equipped with the configuration described in [d]. [A] Shift fork (1) for the shift member (14)
The shift shaft (18) that externally supports the front wheel (1) and the front wheel steering mechanism are interlocked and connected via the linkage mechanism (24).
) is configured such that the shift shaft (18) is slid to the speed-increasing drive side by a steering operation of a predetermined angle or more from the straight-ahead position. [B] Force the shift member (14) or shift fork (17) to the standard drive side. [C] The shift fork (17) is the shift shaft (18)
A pin member (6) connecting the shift fork (17) and the shift shaft (18) is provided so that the shift fork (17) and the shift shaft (18) are slid together with the shift shaft (18). ) in a direction approximately perpendicular to
The shift fork (17) and the shift shaft (18) are configured to be operable into a disconnection position where the shift fork (17) and the shift shaft (18) are disconnected. [2] Speed-up four-wheel drive position (4WD-II) in which the pin member (6) is slid to the connected position;
) to the decoupling position (4WD-I), while sliding the pin member (6) to the decoupling position, the shift fork (17)
A single operating member (16) that can be freely switched over three positions: a two-wheel drive position (2WD), which is operated by contacting and pushing from the standard drive side to a neutral position between the standard drive side and the speed-up drive side. will be established.