JPH07277018A - Four-wheel drive type working vehicle - Google Patents

Abstract

PURPOSE:To reduce the whole size of a front wheel speed change, in a four- wheel drive type working vehicle provided with the front wheel speed change device which drives its front wheels at a higher speed than its rear wheels at the time of turning, when using a one-way clutch as that for a usual standard condition where the front wheels are driven at the roughly same speed as the rear wheels. CONSTITUTION:An input shaft 10 to which power is transmitted and an output shaft 11 to front wheels are disposed, facing each other coaxially, and a one-way clutch 13 is mounted onto the part where the input shaft 10 and the output shaft 11 face each other to form a transmission system for a standard condition. A transmission shaft 14 which receives power branched from the input shaft 10 is disposed in parallel, and a clutch 17 is mounted between the transmission shaft 14 and the output shaft 11 to form a transmission system for an increasing speed condition.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a standard condition in which power is transmitted to the front wheels so that the front wheels and the rear wheels are driven at substantially the same speed, and the front wheels are driven at a higher speed than the rear wheels. A four-wheel drive equipped with a front-wheel transmission that switches from the standard state to a speed-up state when the front wheel is set to a speed-up state in which power is transmitted to the front wheel For model work vehicles.

[0002]

2. Description of the Related Art An example of a four-wheel drive type working vehicle equipped with the above-mentioned front wheel transmission is disclosed in Japanese Utility Model Laid-Open No. 64-42927. In this structure, as shown in FIG. 2 and FIG. 1 of the publication, an electromagnetic clutch (29 in FIG. 2 of the publication) has an output shaft to a front wheel (2 in FIG. 2 of the publication).
1) A transmission gear (25 in FIG. 2 of the publication) is output to the front wheels via a one-way clutch (30 in FIG. 2 of the publication) that is externally fitted and transmits only forward power. It is fitted onto the shaft. Then, the power on the rear wheel side is output to the front wheels via the first transmission shaft (16 in FIG. 2 of the publication) and the second transmission shaft (36, 33 in FIG. 2 of the publication). Is transmitted in parallel to the electromagnetic clutch and the transmission gear.

With the above structure, when the front wheels are steered to the vicinity of the straight ahead position, the electromagnetic clutch is operated to the transmission interruption side, and the power of the rear wheels is transmitted to the first and second transmission shafts, the transmission gear and the one-way. It is in a standard state in which the front wheels and the rear wheels are driven at substantially the same speed by being transmitted to the output shaft to the front wheels via the clutch. Next, when the front wheels are steered over the set angle, the electromagnetic clutch is operated to the transmission side, and the power on the rear wheels is transmitted to the output shaft to the front wheels via the first and second transmission shafts and the electromagnetic clutch. As a result, the front wheels are driven at a higher speed than the rear wheels, and the small wheels can be smoothly turned by the speed-up action of the front wheels. In this case, power is also transmitted to the transmission gear on the standard state side, but the output shaft to the front wheels rotates ahead of the transmission gear due to the action of the one-way clutch, and the transmission is cut off at the position of the one-way clutch. It is in a state.

As described above, if the one-way clutch is provided on the standard state side, when switching from the standard state to the speed increasing state, the standard state is maintained via the one-way clutch until the electromagnetic clutch is operated on the transmission side. The power is being transmitted to the front wheels by the one-way clutch at the moment when the electromagnetic clutch is operated to the transmission side, and the transmission is cut off by the one-way clutch. Become. This eliminates the neutral state in which power is not transmitted to the front wheels when switching from the standard state to the speed increasing state, and the switching operation from the standard state to the speed increasing state can be smoothly performed.

[0005]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
In the structure of Japanese Patent No. 2927, as shown in FIG. 2 of the publication, the first transmission shaft (16 in FIG. 2 of the publication) and the second transmission shaft (FIG. 36 in,
33) and the output shaft to the front wheel (2 in FIG. 2 of the above publication).
As described in 1), three sets of transmission shafts are arranged. Therefore, there is room for improvement in terms of downsizing in the vicinity.
The present invention, in a four-wheel drive type work vehicle, provides a one-way clutch on the standard state side to eliminate the neutral state at the time of a switching operation from the standard state to the speed increasing state, while maintaining the advantage of being close to the front wheel transmission. The purpose is to reduce the size.

[0006]

A feature of the present invention is that the four-wheel drive type working vehicle as described above is configured as follows. In other words, a one-way clutch that arranges the input shaft to which power from the rear wheels is transmitted and the output shaft to transmit power to the front wheels in a concentric manner, and transmits only forward power from the input shaft to the output shaft The forward drive power is transmitted from the input shaft to the output shaft via the one-way clutch in a standard condition in which the front and rear wheels are driven at approximately the same speed by providing the input shaft and the output shaft with the butted portion. So that
A transmission shaft that receives the power branched from the input shaft is arranged in parallel with the input shaft and the output shaft, and a clutch that can be operated for transmission and transmission interruption is provided between the transmission shaft and the output shaft. When the front wheels are driven at a higher speed than the rear wheels, the power for forward movement is set to be transmitted to the output shaft via the input shaft and transmission shaft, and the front wheels are set to the left and right around the straight-ahead position. When operating within the set angle of, the clutch is operated to the transmission disengagement side, and when the front wheel is steered beyond the set angle, the clutch is operated to the transmission side. is there.

[0007]

With the construction of the present invention, as shown in FIG. 2, for example, in a standard state in which the clutch 17 is operated to the transmission disengagement side, the power transmitted to the input shaft 10 is the one-way clutch 13 and the output shaft 11. Is transmitted to the front wheels via the, and the front wheels and the rear wheels are driven at substantially the same speed. When the clutch 17 is operated from the transmission cut-off side to the transmission side by the steering operation of the front wheels, the power transmitted to the input shaft 10 bypasses the one-way clutch 13 and is output via the transmission shaft 14 and the clutch 17. It is transmitted to the shaft 11 and is transmitted to the front wheels in an accelerated state, so that the front wheels are driven at a higher speed than the rear wheels.

In this case, since the input shaft 10 to which the power of the rear wheels is transmitted and the output shaft 11 to the front wheels are arranged concentrically, the input shaft 10 (output shaft 1
Two sets of transmission shafts, 1) and the transmission shaft 14, are arranged. As a result, the conventional technology (the above-mentioned actual exploitation 64-42
As compared with a configuration in which three sets of transmission shafts are arranged (see FIG. 2 of Japanese Patent No. 927), the configuration of the present invention can be downsized as a whole.

When switching from the standard state to the speed increasing state, power is transmitted to the front wheels in the standard state through the one-way clutch until the clutch is operated to the transmission side, and the clutch is transmitted to the transmission side. At the moment of operation, the transmission is cut off by the one-way clutch, and the power is transmitted to the front wheels through the clutch in an accelerated state. As a result, the advantage of eliminating the neutral state in which power is not transmitted to the front wheels during the switching operation from the standard state to the speed increasing state and enabling the smooth switching operation from the standard state to the speed increasing state remains. ing.

[0010]

As described above, in the front wheel transmission of the four-wheel drive type work vehicle, the input shaft and the output shaft are arranged concentrically and the one-way clutch is arranged at the abutting portion, so that the front wheel transmission is close to the front wheel transmission. Can be downsized,
Along with this, it has become possible to reduce the size and weight of the casing. Further, the advantage of the conventional technique of eliminating the neutral state in the switching operation from the standard state to the speed increasing state by the one-way clutch is provided without impairing it.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 1, the engine 3 and the main clutch 4 are arranged in the front part of the airframe supported by the pair of left and right front wheels 1 and the rear wheels 2, and the control part 5 and the mission case 6 are arranged in the rear part of the airframe, and four wheels are arranged. An agricultural tractor that is an example of a drive-type work vehicle is configured.

The power from the engine 3 is transmitted to the mission case 6 via the main clutch 4 and the transmission shaft 7, and is shifted by a transmission (not shown) in the transmission case 6 to the left and right rear wheels 2. Transmitted. And the rear wheel 2
The power branched immediately before is transmitted from the transmission case 6 through the front wheel transmission shaft 8 to the front wheel transmission 9 connected to the lower portion of the main clutch 4, and is transmitted from the front wheel transmission 9 to the left and right front wheels 1. .

Next, the front wheel transmission 9 will be described.
As shown in FIG. 2, the input shaft 1 to which the front wheel transmission shaft 8 is connected
0, and a first output shaft 11 (corresponding to the output shaft) for transmitting power to the front wheels 1 are arranged concentrically with each other, and only one forward power is transmitted from the input shaft 10 to the first output shaft 11. The clutch 13 is provided at the butting portion of the input shaft 10 and the first output shaft 11. As a result, forward power is transmitted from the input shaft 10 to the first output shaft 11 and the transmission gear 11 in a standard state in which the front wheels 1 and the rear wheels 2 are driven at substantially the same speed.
a, 12a and the second output shaft 12, the left and right front wheels 1
Be transmitted to.

A transmission shaft 14 is arranged in parallel with the input shaft 10 and the first output shaft 11, and the transmission gear 10 of the input shaft 10 is arranged.
a and the transmission gear 14a of the transmission shaft 14 mesh with each other. A speed increasing gear 15 is externally fitted to the first output shaft 11 by a needle bearing so as to be relatively rotatable, and the transmission gear 14b of the transmission shaft 14 and the speed increasing gear 15 are meshed with each other. A shift member 16 having a spline structure is slidably fitted onto the first output shaft 11 so as to be freely slidable.
A multi-plate friction clutch 17 (corresponding to a clutch) is provided between the first and the second clutches. The steering mechanism (not shown) of the front wheel 1 and the shift member 16 are mechanically interlocked by a cam mechanism (not shown).

With the above-described structure, when the front wheel 1 is steered within the straight traveling position or within the left and right set angles sandwiching the straight traveling position, the shift member 16 in FIG. 2 separates from the friction clutch 17 to the right side of the drawing. The friction clutch 17 is in the transmission cutoff state. In this state, the power transmitted to the input shaft 10 is transmitted to the front wheels 1 in a standard state via the one-way clutch 13, the first output shaft 11 and the second output shaft 12,
The front wheels 1 and the rear wheels 2 are driven at substantially the same speed.

When the front wheel 1 is steered rightward or leftward over a set angle, such as when turning at the edge of a ridge, the shift member is moved by the action of the steering mechanism and the cam mechanism of the front wheel 1 as shown in FIG. 16 is slid to the left side of the drawing, and the shift member 16 pushes the friction clutch 17 to operate it on the transmission side. As a result, the power transmitted to the input shaft 10 is transmitted to the front wheel 1 in an accelerated state via the transmission shaft 14, the speed increasing gear 15, the friction clutch 17, the first output shaft 11 and the second output shaft 12. The front wheel 1 is driven at a higher speed than the rear wheel 2, and the small wheel turning is smoothly performed by the speed increasing action of the front wheel 1.

When the front wheels 1 are accelerated, the one-way clutch 13 acts on the first output shaft 1 with respect to the input shaft 10.
1 is in a state of preceding rotation, and the one-way clutch 13
At the position of, the transmission is cut off. Then, as described above, when the switching operation is performed from the standard state to the speed increasing state, power is transmitted to the front wheels 1 in the standard state via the one-way clutch 13 until the friction clutch 17 is operated to the transmission side. At the moment when the friction clutch 17 is operated to the transmission side, the transmission is cut off by the one-way clutch 13, and the power is transmitted to the front wheels 1 through the friction clutch 17 in an accelerated state. As a result, the neutral state in which power is not transmitted to the front wheels 1 is eliminated, and the switching operation from the standard state to the speed increasing state can be smoothly performed.

[Other Embodiment] In the embodiment of FIG. 2, the power from the first output shaft 11 is transmitted to the front wheels 1 via the second output shaft 12, but this second output shaft 12 is eliminated. The first output shaft 11 may be extended to the left in the plane of FIG. 2 and connected to the front wheel 1 side. Instead of the friction clutch 17 of FIG. 2, an occlusal type clutch may be formed between the speed increasing gear 15 and the shift member 16, and the shift member 16 may be eliminated to increase the speed increasing gear 15 and the first output shaft 11. An electromagnetic clutch may be provided between and. Further, the front wheel transmission 9 may be arranged in the mission case 6 at the rear of the machine body.

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

[Brief description of drawings]

1] Overall side view of an agricultural tractor

FIG. 2 is a vertical sectional side view of a front wheel transmission device.

[Explanation of symbols]

 1 front wheel 2 rear wheel 10 input shaft 11 output shaft 13 one-way clutch 14 transmission shaft 17 clutch

Claims (1)

[Claims] 1. An input shaft (10) to which power on the rear wheel (2) side is transmitted and an output shaft (1) to transmit power to the front wheel (1).
The one-way clutch (13), which is arranged concentrically with 1) and which transmits only forward power from the input shaft (10) to the output shaft (11), is connected to the input shaft (10) and the output shaft. In front of the front end (1) and the rear wheel (2) being driven at substantially the same speed, the forward drive power is supplied from the input shaft (10) to the one-way clutch in preparation for the abutting portion with (11). The transmission shaft (14) is set so as to be transmitted to the output shaft (11) via (13), and the transmission shaft (14) that receives the power branched from the input shaft (10) is the input shaft (10) and the output shaft (11). And a clutch (17) which is arranged between the transmission shaft (14) and the output shaft (11) and can be operated for transmission and transmission interruption, and when the clutch (17) is operated to the transmission side, the front wheel ( Acceleration state where 1) is driven faster than the rear wheels (2) In this state, the forward power is applied to the input shaft (10) and the transmission shaft (1
4) is transmitted to the output shaft (11), and when the front wheel (1) is operated within a left and right set angle centered on a straight traveling position, the clutch (17) The front wheel (1) and the clutch (17) are connected so that the clutch (17) is operated to the transmission side when the transmission is cut off and the front wheel (1) is steered over a set angle. A four-wheel drive work vehicle that is linked.