JPH0737976Y2 - Work vehicle - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to a structure for displaying a state during turning in a four-wheel drive type work vehicle.

[Conventional technology]

In an agricultural tractor that is an example of a work vehicle, a drive that can switch between a standard four-wheel drive state in which front wheels and rear wheels are driven and a rear two-wheel drive state in which only the rear wheels are driven without power transmission to the front wheels. Some are equipped with a form switching mechanism.

And in recent years, while traveling in the standard four-wheel drive state,
Agricultural tractors equipped with a front wheel transmission that shifts the front wheels more than the rear wheels when the front wheels are steered over a set angle have been put into practical use, and they can be used smoothly on ridges. A small turn is possible.

Further, this agricultural tractor is also configured so that the front wheel transmission can be switched so that the front wheels are not accelerated even if the front wheels are steered in the standard four-wheel drive state.

[Problems to be solved by the device]

If the front wheel speed change device as described above is equipped, the small wheel turning can be easily performed even on soft ground due to the front wheel speed increasing action. It is preferable that the driver can make a small turning turn in a low speed traveling state in which the transmission is operated to the low speed side, and it is preferable to make a prior recognition before turning.

However, in parallel with the shift operation for traveling,
In a work vehicle such as an agricultural tractor that must also operate a work device provided in the machine body, it is said that the front wheels are not accelerated even though the front wheel transmission is switched to the front wheel speed increasing state side. The pilot may make a mistake.

Therefore, in such a case, if the operator performs a steering operation on the front wheels, the driver may unexpectedly make a small turn and swing the driver to the outside due to an unexpected front wheel speed increasing effect. Therefore, it may be difficult to control.

The present invention allows the operator to recognize that a four-wheel drive type work vehicle including a drive mode switching mechanism and a front wheel transmission is in a state in which a small turn can be performed by utilizing the front wheel speed increasing action. The purpose is to be able to.

[Means for Solving the Problems]

A feature of the present invention is that the working vehicle including the above-described drive mode switching mechanism and front wheel transmission is configured as follows.

A first detecting means for detecting a switching state of the drive mode switching mechanism; a second detecting means for detecting a switching state of the front wheel transmission; and a third detecting means for detecting a shifting state of the traveling transmission. When the third detecting means detects that the transmission is operated to the high speed side, the check means is provided to prevent the front wheel transmission from switching to the front wheel speed increasing state, and the first, second and third detecting means are provided. Based on the detection of, the drive mode switching mechanism is operated to the standard four-wheel drive state side, the front wheel transmission is operated to the front wheel speed increasing state side, and the transmission is operated to the low speed side. The display means is provided on or near the control panel.

[Action]

(I) With the configuration of the present invention, first, in the standard four-wheel drive state in which the front wheels and the rear wheels are driven, it is said that the aircraft is traveling in the low speed traveling state in which the transmission is operated to the low speed side. The operator can recognize it by visually observing the display of the display means.

When the restraint means is stopped (because the transmission is operated to the low speed side), the front wheels are driven faster than the rear wheels when the front wheels are steered over the set angle to turn the aircraft. By visually observing the display of the display means, the operator can recognize that the front wheels are in a speed-up state in which a small turn can be made.

(Ii) On the contrary, when there is no display on the display means, the drive state switching mechanism is in the rear two-wheel drive state in which the front wheels are not driven, or the front wheel transmission is not operated to the front wheel speed increasing state side. The presence can be recognized by the operator by visually observing that there is no display on the display means.

If not in the above two states, in the standard four-wheel drive state, the transmission is operated to the high speed side and the restraint means is operating, and the front wheels are steered to the set angle or more to turn the aircraft. Even if the driver recognizes that the front wheels are not driven at an increased speed and that the front wheels and the rear wheels are driven at substantially the same speed by observing that there is no indication on the display means. You can

Accordingly, when it is desired to make a small turn by the front wheel speed increasing action, the drive state switching mechanism may be switched to the standard four-wheel drive state side, or the front wheel transmission may be switched to the front wheel speed increasing state side. . If the above two states are not satisfied, the transmission is operated to the high speed side and the restraint means is operating. Therefore, the transmission may be operated to the low speed side to stop the restraint means.

(Iii) Since the above-mentioned display means is provided on the control panel or in the vicinity of the control panel, which is easily noticeable by the driver who is driving, the driver should overlook the state of the above (i) and (ii). Without, it can be surely recognized.

[Effect of device]

As described above, it becomes possible for the operator to surely recognize whether or not it is possible to make a small turn by utilizing the front wheel speed-increasing effect, and the driver can recognize the unexpected front wheel speed-increasing effect. It was possible to improve the maneuverability of the work vehicle because it was not shaken to the outside.

Further, when switching to a state in which a small turn can be made by the front wheel speed increasing action, the drive state switching mechanism is switched to the standard four-wheel drive state side, the front wheel transmission is switched to the front wheel speed increasing state side, or the transmission is changed. Since it is only necessary to perform the operation of the low speed side operation, it is possible to easily return to the state in which the small turn can be performed by the front wheel speed increasing action.

〔Example〕

Hereinafter, a four-wheel drive type agricultural tractor, which is an example of a work vehicle in an embodiment of the present invention, will be described with reference to the drawings.

As shown in FIG. 7, an engine (4), a main clutch (5), and a mission are mounted on a body frame (3) that rotatably supports a pair of left and right steering type front wheels (1) and rear wheels (2). A case (6) and a control unit (7) are mounted, a lift arm (8) for connecting and lifting various working devices such as a rotary tiller to the rear of the machine body, and a PTO shaft (9) for transmitting power to the working device. ) Is provided to configure a four-wheel drive agricultural tractor.

As shown in FIGS. 1 and 7, the power of the engine (4) is transmitted through the main clutch (5) and the power transmission shaft (11) to the main transmission (not shown) of the transmission case (6) and the auxiliary transmission. It is transmitted to a transmission (not shown) (corresponding to a transmission for traveling), gear-shifted, and transmitted to the rear wheels (2). The power branched from immediately before the rear wheel (2) is transmitted to a drive mode switching mechanism (not shown), is sent to the front wheel transmission (10), and undergoes a speed change operation to output the front wheel output shaft (15) and the front wheel differential mechanism. It is configured to be transmitted to the front wheel (1) via (1a).

Then, as shown in FIG. 1, the drive mode switching mechanism is driven by the switching lever (41) to the standard four-wheel drive state in which power is transmitted to the front wheels (1) and the rear wheels (2) and to the front wheels (1). The power transmission is cut off to switch to the rear two-wheel drive state in which only the rear wheels (2) are driven.

Next, the front wheel transmission (10) will be described. As shown in FIG. 2, the front wheel transmission (10) is arranged at the front end of the transmission case (6), and the power from the drive mode switching mechanism is transmitted by gear transmission through the branch power shaft (12). (14), and the front wheel output shaft (15) is arranged concentrically with the branch power shaft (12). First and second output gears (16) and (17) are loosely fitted onto the transmission shaft (14),
First and second passive gears (18) and (19) that mesh with the first and second output gears (16) and (17) are fixed to the front wheel output shaft (15).

A multi-plate hydraulic clutch (21) is mounted between the transmission shaft (14) and the second output gear (17), and the gear member (34) is slidable on the back surface of the hydraulic clutch (21) with a spline structure. Attached to the piston member (2) of the hydraulic clutch (21).
0) and the gear member (34) are connected via two sets of pins (13). Although the pin (13) and the gear member (34) are bolt-connected, the piston member (20) and the pin (13) are connected to the end (13a) of the pin (13) as shown in FIG. )
After being inserted into the connecting hole of the piston member (20), the end portion (13a) of the pin (13) is expanded by a punch or the like as shown in FIG.

In the state shown in FIG. 2, the piston member (20) is separated from the clutch disc (21a) of the hydraulic clutch (21) by the urging force of the spring (28), and the gear member (34) is moved to the first output gear (16). ), The power is transmitted from the first output gear (16) to the front wheel output shaft (15) with the driving speeds of the front wheel (1) and the rear wheel (2) being substantially equal.
Next, when hydraulic oil is supplied to the hydraulic clutch (21), the piston member (20) moves to the left in the drawing, the gear member (34) separates from the first output gear (16), and the clutch disc Press (21a). As a result, power is transmitted from the second output gear (17) to the front wheel output shaft (15) in a state where the front wheel (1) is accelerated more than the rear wheel (2).

Next, the structure of the control valve (22) for supplying and discharging hydraulic oil to and from the hydraulic clutch (21) will be described. As shown in FIG. 4, the control valve (22) is of a spool type, and the spool (23) is biased toward the protruding side by a spring (24). Spool (2
A pitman arm (25) for steering the front wheel (1) is arranged on the protruding end side of 3), and a pit unarm (25)
A cam (27) having a recess is attached to the base of the.

The position of the pitman arm (25) in FIG. 4 is a position in a substantially straight state, and the hydraulic oil sent from the pump (44) to the pump port (P) of the control valve (22) is switched to the oil passage (26). Oil is drained from the drain port (D) through the valve (33) (corresponding to a restraint means) and the oil passage (35), and the hydraulic oil from the hydraulic clutch (21) of the front wheel transmission (10) is also discharged. Oil is drained from the clutch port (C) through the drain port (D). In this state, the front wheel transmission (10) is in a state in which the gear member (34) is engaged with the first output gear (16) by the urging force of the spring (28) as shown in FIG.

Then, when the manipulating handle (30) shown in FIG. 7 is operated and the pitman arm (25) is swung more than the set value,
As shown in FIG. 5, the spool (23) is provided by the cam (27).
Is pushed in, and the oil passage (35) and the clutch port (C) are in communication with each other. This allows the front wheel transmission (1
The hydraulic oil is supplied to the hydraulic clutch (21) of (0) to enter the hydraulic clutch, and the front wheel (1) is in a state of being driven at a higher speed than the rear wheel (2). Further, the spool (23) is provided with a relief valve (31) for discharging excess hydraulic oil to secure the clutch pressure of the hydraulic clutch (21).

Next, by steering the steering wheel (30), the front wheel (1)
A structure for switching between the front wheel accelerating state in which the vehicle is accelerated and the non-accelerating state will be described. As shown in FIG. 4, the switching valve (33) provided in the control valve (22) is of a rotary type, and an operating portion (29) for rotating the switching valve (33) from the outside.
(Corresponding to the third detecting means) is provided, and the operation unit (2
9) and the front wheel speed-increasing lever (32) connect the connecting rod (36).
(Corresponding to a third detecting means). Fourth
The state shown in the figure is a state in which the front wheel speed increasing lever (32) is lifted upward to the front wheel speed increasing state side, and the oil passages (26) and (35) are in communication with each other so that the front wheel (1) turns the rear wheel ( The front wheels are in an accelerated state in which the speed is increased from that in 2).

On the contrary, when the front wheel speed increasing lever (32) is pushed down to the standard four-wheel drive state side, the switching valve (33) is rotated to the state shown in FIG. In this state, the hydraulic oil fed into the pump port (P) is always discharged to the drain port (D) through the switching valve (33), so that the hydraulic pressure is maintained even if the steering handle (30) is steered. No hydraulic oil is supplied to the clutch (21), and the front wheels (1) and the rear wheels (2) maintain a substantially equal drive speed. Then, as shown in FIGS. 1 and 4, a second limit switch (38) (corresponding to a second detecting means) for detecting the operation of the front wheel speed increasing lever (32) to the front wheel speed increasing state is arranged. Has been done.

As shown in FIGS. 1 and 4, the auxiliary transmission lever (39) and the operating portion (29) for the auxiliary transmission are provided with a wire (40) (third part).
(Corresponding to a detection means). As a result, when the auxiliary speed change lever (39) is operated to the high speed side while the front wheel speed increasing lever (32) is being operated to the front wheel speed increasing state side, the wire (40) is pulled and the switching valve (33) is operated. ) Is switched to the state shown in FIG. 6, and the front wheel speed increasing lever (3
2) is operated to the standard four-wheel drive state side below. As a result, even when the front wheel (1) is steered by a set angle or more during high-speed traveling, the front wheel (1) is not driven to speed up,
The driving speeds of the front wheels (1) and the rear wheels (2) are kept substantially equal.

As shown in FIG. 1, a first limit switch (37) for detecting the operation to the standard four-wheel drive state side with respect to the switching lever (41) for switching the drive mode switching mechanism (to the first detecting means). Equivalent) is provided. Then, the display lamp (42) (corresponding to the display means) that lights up when the first and second limit switches (37), (38) are in the ON state,
It is provided on the control panel (43) as shown in FIGS. 1 and 7.

As a result, the state in which the display lamp (42) is lit means that the switching lever (41) is operated to the standard four-wheel drive state side as shown in FIG. When the vehicle is in a low-speed running state in which it is operated to the low speed side, and the front wheel speed increasing lever (32) is steered to the front wheel speed increasing state (the steering handle (30) is steered over a set angle or more, the front wheel (1) moves to the rear wheel (2). It means that it is in a state in which it is operated to be driven more speedily than)).

This indicator lamp (42) is not on the control panel (43)
It may be provided in the vicinity of the control panel (43) such as the support portion of the control handle (30).

It should be noted that reference numerals are added to the claims of the utility model for convenience of comparison with the drawings, but the present invention is not limited to the structure of the accompanying drawings by the entry.

[Brief description of drawings]

The drawings show an embodiment of a work vehicle according to the present invention. FIG. 1 is a schematic view showing a front wheel transmission, a front wheel speed-increasing lever, an auxiliary transmission lever, a switching lever and the like, and FIG. 2 is a front wheel transmission. FIG. 4 is a vertical side view of FIG. 3, and FIGS.
FIG. 5 is a view showing a state in which the control valve and the control valve are linked to the auxiliary shift lever and the front wheel speed increasing lever. FIG. 5 is a side view showing a state in which the pitman arm is rocked by the steering handle from the state shown in FIG. 6 and 6 are side views showing a state in which the switching valve is operated to the oil drain side from the state shown in FIG. 4, and FIG. 7 is an overall side view of the agricultural tractor. (1) ... front wheel, (2) ... rear wheel, (10) ... front wheel transmission, (29), (36), (40) ... third detection means, (3
3) …… Checking means, (37) …… First detecting means, (38)…
… Second detection means (42) …… Display means, (43) …… Control panel.

Claims (1)

[Scope of utility model registration request] 1. A drive mode switching mechanism capable of switching between a standard four-wheel drive state in which a front wheel (1) and a rear wheel (2) are driven and a rear two-wheel drive state, and a set angle of the front wheel (1). Due to the above steering operation, the front wheel (1) is driven faster than the rear wheel (2) and the front wheel (1) is not accelerated regardless of the steering operation of the front wheel (1). A work vehicle equipped with a front wheel transmission (10) capable of switching to and between a first detection means (37) for detecting a switching state of the drive mode switching mechanism and a switching state of the front wheel transmission (10). A second detecting means (38) for detecting and a third detecting means (29), (36), (40) for detecting a shift state of the traveling transmission, the third detecting means (29), When it is detected by (36) and (40) that the transmission is operated to the high speed side,
A check mechanism (33) for preventing the front wheel transmission (10) from switching to a front wheel speed increasing state is provided, and the first, second and third detecting means (37), (38), (29), (3) are provided.
6) and (40), the drive mode switching mechanism is operated to the standard four-wheel drive state side, the front wheel transmission (10) is operated to the front wheel speed increasing state side, and the transmission is A work vehicle provided with a display means (42) for indicating that the vehicle is being operated at a low speed side on the control panel (43) or in the vicinity thereof.