JP2721084B2 - Travel transmission structure of work vehicle - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a traveling power transmission structure for a working vehicle having a pair of left and right traveling devices such as a multi-wheel type and a crawler type with four wheels on one side.

[0002]

2. Description of the Related Art As an example of the working vehicle as described above, there is a combine equipped with a pair of left and right traveling devices of a crawler type. It is possible to switch between two states: a state of turning (or a state in which one traveling device is driven forward at a lower speed than the other to make a gentle turn) and a state in which one traveling device is stopped to perform a pivot turn. There are things that make up. An example of such a turning state switching structure is disclosed in Japanese Patent Application Laid-Open No. Hei 3-276877. In this structure, the forward rotation power for straight traveling is transmitted to a shift gear (see FIG.
14), the transmission is shifted to three stages and transmitted to the transmission shaft (the second 15 in the above-mentioned publication), and the forward rotation power for straight traveling from the transmission shaft is transmitted to the gear (see FIG. 2 in the above-mentioned publication). 1
8) (corresponding to a linear gear) to the first transmission gear (19 in FIG. 2 of the above-mentioned publication). This allows
Left and right side gears (21R and 21L in FIG. 2 of the above publication)
Is linked to the first transmission gear, forward rotation power of the same speed is transmitted from the left and right side gears to the left and right traveling devices, and the aircraft advances straight.

A pair of left and right second gears is
Transmission gears (26R, 26L in FIG. 2 of the above publication) are arranged, and the power from the aforementioned transmission shaft (15 in FIG. 2 of the above publication) is converted into reverse rotation power by the gear (62 of FIG. 2 of the above publication). After being converted, the reverse rotation clutch (30 in FIG. 2 of the above publication)
(Corresponding to switching means). Thereby, for example, if the left side gear is slid, and the reverse clutch is operated while being linked to the second transmission gear,
The reverse rotation power is transmitted to the left traveling device via another transmission shaft (27 in FIG. 2 of the above publication) and a gear (29 in FIG. 2 of the above publication) (corresponding to a turning gear), and a second transmission gear. The traveling device on the left is driven in reverse to turn left. The other transmission shaft (27 in FIG. 2 of the above publication) is also provided with a side brake (28 in FIG. 2 of the above publication) (corresponding to a switching means). Thereby, for example, the left side gear is shifted to the second
If the side brake is turned on and operated while being linked to the transmission gear (at this time, the reverse clutch 30 is disengaged),
The left traveling device stops and you can turn left. As described above, the switching operation between the super pivot turning state and the pivot turning state can be performed by the sliding operation of the left and right side gears to the second transmission gear and the engagement operation of the reverse rotation clutch or the side brake.

[0004]

In the above-mentioned conventional structure, a transmission shaft (15 in FIG. 2 of the above-mentioned publication) for transmitting the forward rotation power for straight traveling to the first transmission gear, and a super turning point Shaft for state and pivoting state (27 in FIG. 2 of the above publication)
And are arranged separately. Therefore, it is necessary to secure a relatively large space for disposing the two transmission shafts in the transmission case, so that there is room for improvement in terms of space saving and miniaturization of the structure. The present invention relates to a traveling power transmission structure of a working vehicle having a switching operation state between a super pivot turning state (slow turning state) and a pivot turning state. The purpose is to reduce the size.

[0005]

The feature of the present invention resides in the following construction in the traveling power transmission structure for a working vehicle as described above. In other words, a transmission shaft is provided that supports a pair of turning gears that mesh with each of the pair of left and right second transmission gears so as to be integrally rotatable, and the low-speed forward or reverse rotation power from the transmission device for traveling on the better side is provided. It is provided with switching means that can be switched between a state of transmitting to the transmission shaft and a state of stopping and holding the transmission shaft by blocking the transmission from the upper side, and for receiving straight forward power from the transmission for forward rotation. The gear is rotatably fitted on the transmission shaft so as to be relatively rotatable, and is engaged with the first transmission gear.

[0006]

With the construction described above, for example, as shown in FIG. 1, the forward rotation power for straight traveling from the transmission 42 for traveling on the upper side is externally rotatable relative to the straight traveling gear 23 (to the transmission shaft 19). To the first transmission gear 2 from the straight-moving gear 23.
4 is transmitted. Thereby, the left and right side gears 26
Is linked to the first transmission gear 24, the forward rotation power for straight traveling is transmitted to the left and right traveling devices 27 via the side gears 26, and the aircraft advances straight. Next, as shown in FIG. 1, a state in which the low-speed forward rotation power or the reverse rotation power from the transmission 42 is transmitted to the transmission shaft 19 by the switching means (in the structure of FIG. 1, the first transmission gear 24, Transmission to the transmission shaft 19 via the gears 44 and 45 and the turning gear 32R). In this state, for example, the left side gear 26 is connected to the first transmission gear 24.
From the second transmission gear 30,
The low-speed forward rotation power or the reverse rotation power of the left second transmission gear 30 is transmitted to the left traveling device 27, and the aircraft slowly turns left or super turning. Next, if the transmission to the transmission shaft 19 is cut off by the switching means and the transmission shaft 19 is stopped and held, the left and right second transmission gears 30 are stopped and held. In this state, for example, when the left side gear 26 is separated from the first transmission gear 24 and is interlocked with the second transmission gear 30, the left traveling device 27 stops and the aircraft turns left and right. is there.

As described above, in the present invention, as shown in FIG. 1, the straight-moving gear 23 (cylindrical shaft 39) for transmitting the straight forward power to the first transmission gear 24, and the turning transmission The shaft 19 is at the same position. Therefore, unlike the conventional structure, it is not necessary to arrange two transmission shafts for straight traveling and turning, and only the space for arranging one transmission shaft 19 is sufficient, and one transmission shaft in the transmission case is required. Space for disposing the shaft can be omitted.

[0008]

As described above, in the traveling transmission structure of the working vehicle having the switching operation structure between the super pivot turning state (slow turning state) and the pivot turning state, two transmissions for straight traveling and turning are provided. Since it is sufficient to arrange only one transmission shaft without securing the space for disposing the shaft, it is possible to save space and reduce the size of the structure in the transmission case, which is advantageous in terms of production cost. was gotten.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a structure inside a transmission case 1 of a traveling system of a combine, which is one of the working vehicles, in which power from an engine (not shown) uses a belt transmission mechanism (not shown) provided with a tension clutch. The power is transmitted to the input pulley 3 of the belt-type continuously variable transmission 2 through the transmission. Power from the output shaft 4 of the belt-type continuously variable transmission 2 is cut via a first gear 5, a second gear 6, a first transmission shaft 7, a third gear 8, a fourth gear 9 and an output pulley 10 ( (Not shown).

A forward gear 11 and a reverse gear 12 are rotatably fitted to the first transmission shaft 7 so as to be relatively rotatable. A shift gear 13 is slidably movable between the forward and reverse gears 11 and 12 by a spline structure. Is fitted outside. With this structure, when the shift gear 13 is engaged with the forward gear 11, the power of the first transmission shaft 7 is moved forward and the fifth gear 14
(Occlusion with the forward gear 11) to the second transmission shaft 15. When the shift gear 13 is engaged with the reverse gear 12, the power of the first transmission shaft 7 is moved in reverse and the reverse gear 12, the sixth gear pair 16, and the fifth gear 14 (the sixth gear pair 1).
6 and is transmitted to the 22nd transmission shaft 15.

A first high-speed gear 17 is fitted on the second transmission shaft 15 so as to be relatively rotatable, and a shift gear 18 is fitted with a spline structure so as to be slidable. A cylindrical shaft 39 is externally rotatably fitted to a third transmission shaft 19 (corresponding to a transmission shaft which is a feature of the present invention) disposed in the transmission case 1. 2
0, the medium speed gear 21 and the second high speed gear 22 are fixed, and the first and second high speed gears 17 and 22 are in mesh.

As a result, the shift gear 18 is slid to operate the first high-speed gear 17, the medium-speed gear 21, and the low-speed gear 2.
0, the forward rotation power from the second transmission shaft 15 can be shifted to three stages of high, medium, and low. This forward rotation power is transmitted from the linear gear 23 fixed to the cylindrical shaft 39 to the first rotation. The power is transmitted to one transmission gear 24. As described above, the shift gear 18, the cylindrical shaft 39, the low-speed gear 20, and the like constitute a gear transmission type transmission 42 for traveling.

Right and left side gears 26 are externally fitted to a support shaft 25 supporting the first transmission gear 24 so as to be relatively rotatable, and input gears 28 of left and right traveling devices 27 always mesh with the left and right side gears 26. ing. As a result, the left and right side gears 26 engage with the first transmission gear 24 (the first transmission gear 2).
4) to transmit the forward rotation power for straight traveling to the left and right crawler-type traveling devices 27. The spring 29 connects the side gear 26 to the first transmission gear 2.
It is biased to the 4 side.

A pair of second transmission gears 3 are provided on the left and right sides of the support shaft 25.
0 is externally fitted, and a multi-plate friction clutch 31 is provided between the left and right second transmission gears 30 and the side gears 26. A left turning gear 32L is fixed to one end of the third transmission shaft 19, and the left turning gear 32L is connected to the left second transmission gear 30.
A right turning gear 32R (corresponding to a switching means) is externally slidably fitted to the other end of the third transmission shaft 19 by a spline structure, and the right turning gear 32R is It is engaged with the second transmission gear 30. The seventh gear 44 is fixed to the first transmission gear 24, and the third transmission shaft 1
An eighth gear 45 externally fitted to the gear 9 is engaged with the seventh gear 44. Further, a switching lever 41 capable of sliding the right turning gear 32R is provided in a control section of the fuselage.

With the above structure, as shown in FIG. 1, the switching lever 41 is operated to the gentle turning position and the right turning gear 32R is operated.
Is slid leftward on the paper, the right turning gear 32R
Are engaged with the eighth gear 45. Accordingly, the forward rotation power for straight traveling transmitted to the first transmission gear 24 is transmitted to the seventh gear 4.
The power is converted into low-speed forward rotation power via the fourth and eighth gears 45, the right turning gear 32R, the third transmission shaft 19, and the left turning gear 32L, and transmitted to the left and right second transmission gears 30. Therefore, for example, when the left side gear 26 is operated to be separated from the first transmission gear 24 and the friction clutch 31 is pressed and operated by the pressing portion 43 of the left side gear 26 (corresponding to an interlocking connection position with the second transmission gear 30), The low-speed forward rotation power of the left second transmission gear 30 is transmitted to the left traveling device 27, and the aircraft slowly turns left due to the speed difference between the left and right traveling devices 27.

Next, when the switching lever 41 is operated to the pivot position and the right turning gear 32R is slid rightward on the drawing surface, the right turning gear 32R is separated from the eighth gear 45, and the transmission case 1 Engages with the convex portion 1a on the inner surface of. Thus, the left and right second transmission gears 30 are stopped and held by the right turning gear 32R, the third transmission shaft 19, and the left turning gear 32L. Thereby, for example, the left side gear 26 is operated to be separated from the first transmission gear 24, and the left side gear 26
When the friction clutch 31 is pressed and operated by the pressing portion 43, the left traveling device 27 is braked, and the machine body turns left and right.

Next, the sliding operation structure of the left and right side gears 26 will be described. As shown in FIGS. 2 and 1, an operation arm 38 for sliding the left and right side gears 26 is provided.
And a hydraulic cylinder 33 (corresponding to an operating means) for swinging the hydraulic cylinder. In this case, the hydraulic cylinder 33
Is provided with a spring (not shown) for urging the hydraulic cylinder 33 toward the contraction side.
Is supplied to an electromagnetically operated control valve 35 for When the hydraulic cylinder 33 is extended until the side gear 26 moves away from the first transmission gear 24 and moves to the neutral stop position where the friction clutch 31 is not pressed and operated, the hydraulic oil is removed from the hydraulic cylinder 33 and the hydraulic cylinder 33 is removed. A drain oil passage 36 for stopping at the neutral stop position is provided, and a variable relief valve 37 is provided in the drain oil passage 36.

Next, the control valve 35 and the variable relief valve 37
The operation of is described. The state shown in FIG. 2 and FIG.
The left and right side gears 26 are in a straight running state in which the first transmission gears 24 are engaged. In this state, for example, when the operation lever 40 is operated to the left first turning position L1, only the control valve 35 is switched to supply the hydraulic oil to the left hydraulic cylinder 33, and the left side gear 26 slides to the left on the paper. First
Move away from the transmission gear 24. In this case, the variable relief valve 3
7 is fully opened, the drain oil passage 36 is opened at the neutral stop position before the left side gear 26 presses the friction clutch 31, and the hydraulic oil flows out of the variable relief valve 37, so that the left side gear 26 is in the neutral position. Stop at the stop position. This is a state in which the transmission to the left traveling device 27 is cut off, and the aircraft gradually turns left.

When the operating lever 40 is operated to the left second turning position L2, the variable relief valve 37 is throttled, the hydraulic cylinder 33 is extended from the neutral stop position, and the left friction clutch 31 is engaged. Is done. in this case,
As shown in FIG. 1, if the switching lever 41 is operated to the gentle turning position to engage the right turning gear 32R with the eighth gear 45, the left traveling device 27 is driven forward at low speed to make a gentle turning. Can be performed. Further, the left first turning position L1 and the second turning position L2
When the operating lever 40 is operated between the above state, the operating oil is released from the hydraulic cylinder 33 from the above-described state, and the friction clutch 3
The pressing force to 1 is reduced. Thereby, the friction clutch 31 slips and the forward rotation speed of the left traveling device 27 can be changed.

Conversely, if the switching lever 41 is operated to the pivot position to engage the right turning gear 32R with the projection 1a of the transmission case 1 and stop and hold it, the operation lever 40 is operated. When operated to the left second turning position L2, the left traveling device 27 is braked to perform a pivot turn. or,
Move the operating lever 40 to the left first and second turning positions L1 and L2.
In this case, the friction clutch 31 slides and the braking force on the left traveling device 27 can be changed as described above.
The above operation is performed on the right first turning position R1 and the second turning position R
2 is performed similarly.

As shown in FIG. 1, the first high-speed gear 17 is provided with a main brake 46 for braking and stopping the entire body. As a result, in the straight traveling state in which the left and right side gears 26 are engaged with the first transmission gear 24, the main brake 46
Is operated on the braking side, the braking action of the main brake 46 is applied to the left and right traveling devices 27 via the first high-speed gear 17, the cylindrical shaft 39 and the first transmission gear 24.

When the main brake 46 is operated to the braking side in a gentle turning state in which the right turning gear 32R is engaged with the eighth gear 45 and one friction clutch 31 is pressed and operated by one side gear 26, the main braking is performed. The braking action of the first high-speed gear 17, the cylindrical shaft 39 and the first transmission gear 2
4 and one of the traveling devices 27, the first transmission gear 24, the eighth gear 45, and the right or left turning gear 32.
Via the R and 32L, braking is also applied to the traveling device 27 on the low-speed drive side.

Then, the right turning gear 32R is engaged with the projection 1a of the transmission case 1, and the one side gear 26
In the pivoting state in which one of the friction clutches 31 is pressed and operated, the braking action of the main brake 46
It is applied to one traveling device 27 via the high-speed gear 17, the cylindrical shaft 39 and the first transmission gear 24. The other traveling device 27 is still being braked by the fixed second transmission gear 30 and the friction clutch 31.

As described above, by providing the main brake 46 for the first high-speed gear 17 in the transmission 42 for traveling, the vehicle can travel left and right in any of the straight running state, the gentle turning state and the pivot turning state. The device 27 can be braked. Since the power in the transmission 42 for traveling is relatively high rotation and low torque, a sufficient braking action can be obtained even with the main brake 46 having a relatively small capacity.

[Alternative Embodiment] In the embodiment of FIG. 1, a state in which low-speed forward rotation power is transmitted to the second transmission gear 30 by the sliding operation of the right turning gear 32R (slow rotation state), and a state in which the second transmission is transmitted. The gear 30 is configured to be switched to two states of a state in which the gear 30 is stopped and held (a pivot state).
A state in which reverse rotation power is transmitted instead of low-speed forward rotation power, and a reverse rotation power is transmitted to the second transmission gear 30 (a super-spinning state in which one of the traveling devices 27 is reversely driven); The second transmission gear 30 may be configured to be freely operable to switch between two states, that is, a state where the second transmission gear 30 is stopped and held (a pivot turn state). In the embodiment of FIG. 1, the side gear 26 and the first transmission gear 24 have an occlusion structure, and the friction clutch 31 is provided between the side gear 26 and the second transmission gear 30. A friction clutch may be provided therebetween, and the side gear 26 and the second transmission gear 30 may be configured in an occlusal structure, both may be configured in an occlusal structure, or both may be provided with a friction clutch.

Incidentally, reference numerals are provided in the claims for convenience of comparison with the drawings, but the present invention is not limited to the configuration of the attached drawings by the entry.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a transmission structure in a transmission case.

FIG. 2 is a hydraulic circuit diagram for sliding operation of left and right side gears.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 19 Transmission shaft 23 Straight running gear 24 First transmission gear 26 Side gear 27 Traveling device 30 Second transmission gear 32R, 32L Turning gear 32R Switching means 33 Operating means 42 Traveling transmission

Claims (1)

(57) [Claims] A first transmission gear (24) to which forward rotation power for straight traveling is transmitted to each of a pair of left and right side gears (26) for transmitting power to each of a pair of left and right traveling devices (27). ) And a pair of left and right second transmission gears (30) to which low-speed forward or reverse rotation power is transmitted, and each of the left and right side gears (26) is connected to the first transmission gear (24). And the second transmission gear (3
0) a traveling transmission structure of a working vehicle provided with an operation means (33) that can slide freely independently of an interlocking connection position with the second transmission gear (30). A transmission shaft (19) supporting a pair of turning gears (32R) and (32L) to be rotatable integrally with each other, and receiving a low-speed forward or reverse rotation power from a transmission device (42) for traveling on the upper side. A switching means (32R) operable to switch between a state in which the transmission is transmitted to the transmission shaft (19) and a state in which the transmission from the superior side is interrupted to stop and hold the transmission shaft (19);
A straight-moving gear (23) that receives the straight-moving forward power from the transmission (42) is fitted around the transmission shaft (19) so as to be rotatable relative to the transmission shaft (19), and is engaged with the first transmission gear (24). A transmission structure for a working vehicle.