JP2583777Y2 - Work vehicle traveling speed change structure - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a vehicle for driving power from an engine through a continuously variable transmission, a gearshift type stepped gear transmission and a pair of left and right side clutches (for turning). The present invention relates to a traveling speed change structure of a working vehicle configured to transmit the power to a vehicle.

[0002]

2. Description of the Related Art An example of a working vehicle as described above is an agricultural combine. A conventional combine has a shift lever for shifting a continuously variable transmission and a shift lever for shifting a gear transmission. There are those provided in.
Continuously variable transmissions include a hydrostatic type and a belt type using a split pulley. Such a continuously variable transmission can be directly operated by a shift lever without disengaging a traveling system clutch. A shift operation is possible. A shift operation during work traveling, traveling on a road, or the like is performed mainly by performing a shift operation on the continuously variable transmission.

[0003]

Further, in a vehicle equipped with a gear transmission and a continuously variable transmission, an attempt is made to operate a transmission lever during traveling in consideration of shifting the gear transmission during traveling. In this case, since the surface pressure on the shift gear of the gear transmission is increased due to the power from the continuously variable transmission and the running resistance applied to the traveling device, the operation of the shift lever becomes heavy, and the shifting operation is difficult. It has become something. In particular, when the traveling resistance applied to the traveling device becomes extremely large, such as when turning, the difficulty of the speed change operation becomes more remarkable, and improvement is desired.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a structure in which a shift operation of a gear transmission can be performed lightly when the vehicle is stopped and when the vehicle is running.

[0005]

The feature of the present invention resides in the following construction in the traveling speed change structure of a working vehicle as described above. That is, the power from the engine is transmitted to each of the left and right traveling devices via a continuously variable transmission, a gear shift type stepped gear transmission, and a pair of left and right side clutches. The gearshift lever for gearshift operation is provided with an artificial operation tool capable of simultaneously disengaging and operating the left and right side clutches.

[0006]

With the above-described structure, when a gearshift operation is performed by a gearshift for a gear transmission, the left and right side clutches are simultaneously disengaged by operating a manual operation tool provided on the gearshift. This way,
The transmission between the gear transmission and the traveling device is cut off, and the lower part of the gear transmission enters a free rotation state.
In such a state, even if the power is transmitted from the upstream continuously variable transmission to the gear transmission, the surface pressure generated on the shift gear in the gear transmission becomes small, and the shift gear is shifted by the shift lever. The sliding operation, that is, the shifting operation of the gear transmission can be performed lightly. In particular, in the present invention, since the artificial operation tool is provided on the shift lever itself, it becomes possible to operate the artificial operation tool with a hand holding the shift lever, and the operability is not reduced.

[0007]

As described above, by shifting the lower left and right side clutches during the gear shifting operation of the gear transmission, the gear shifting operation by the shift lever can be performed lightly even when stopped or running. Operability was improved. In addition, since the manual operation device for the side clutch is provided on the shift lever itself, it is possible to minimize a decrease in operability due to the manual operation device.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. FIG. 3 shows a structure in a transmission case 2 of a traveling system of a combine, which is one of the working vehicles, and power from an engine (not shown) is transmitted via a belt transmission mechanism (not shown) having a tension clutch. And transmitted to the input pulley 16 of the hydrostatic continuously variable transmission M. Continuously variable transmission M
The power from the output shaft 1 is transmitted from the first transmission shaft 14 to the reaping unit (not shown) via the output pulley 15.

Power from the output shaft 1 is transmitted to the second transmission shaft 21 via the first gear 10. This second transmission shaft 21
, A first high-speed gear 22 is fitted to the outside so as to be relatively rotatable, and the shift gear 3 is slidably mounted in a spline structure. A low-speed gear 25, a medium-speed gear 8, and a second high-speed gear 23 are attached to the third transmission shaft 24 in a spline structure, and the first and second high-speed gears 22, 23 are engaged. Thus, by sliding the shift gear 3 to engage the first high-speed gear 22, the medium-speed gear 8, and the low-speed gear 25, the power can be shifted to three stages of high, medium, and low. First output gear 7 to be engaged
Is transmitted to As described above, the gear transmission 31
(Corresponding to a gear transmission for traveling).

Right and left side gears 12 are rotatably fitted on the support shaft 6 that supports the first output gear 7, and input gears 18 of the left and right axles 5 always mesh with the left and right side gears 12. ing. As a result, a pair of left and right side clutches FC is formed between the right or left side gear 12 and the first output gear 7 in an occlusal manner.
2 is engaged with the first output gear 7 so that the forward rotation power is supplied to the left and right crawler-type traveling devices 4.
To communicate. Further, the spring 19 biases the side gear 12 toward the first output gear 7 (the entrance side of the side clutch FC).

A pair of second output gears 9 are externally fitted on the left and right sides of the support shaft 6, and a multi-plate friction clutch RC is provided between the second output gear 9 and the support shaft 6. On the other hand, the second gear 11 is fixed to both ends of the third transmission shaft 24, and the sleeve 38 is externally fitted to the bearing so that the third transmission shaft 24 can be slid left and right. In this case, since the low-speed gear 25 and the medium-speed gear 8 are positioned by the sleeve 26, the position of the low-speed gear 25 and the medium-speed gear 8 does not change even if the third transmission shaft 24 is slid.

FIG. 3 shows a state in which the third transmission shaft 24 is slid to the right in the drawing.
The left and right second gears 11 are in direct engagement with the left and right second output gears 9. As a result, forward rotation power that is lower in speed than the forward rotation power transmitted from the third transmission shaft 24 to the first output gear 7 is transmitted from the third transmission shaft 24 to the second output gear 9. Therefore, for example, when the left side gear 12 is separated from the first output gear 7 and the friction clutch RC is pressed and operated by the pressing portion 17 of the left side gear 12, the left traveling device 4 is driven at a lower speed than the right traveling device 4. It is rolled and the aircraft slowly turns left due to the speed difference between the left and right traveling devices 4.

As shown in FIG. 3, a manually operated switching lever 32 for sliding operation of the third transmission shaft 24 is provided in a control section of the fuselage. A shift member 29 is slidably attached to each of the left and right fourth transmission shafts 39 in a spline structure, and a shift fork 30 is attached to the left and right sides of the third transmission shaft 24 so as to be relatively rotatable. Forks 30 are engaged with the shift members 29, respectively.

With the above structure, the switching lever 32 is
Operating from the gentle turning position to the pivot turning position of the third transmission shaft 2
4 slides to the left in the drawing, the second gear 11 is separated from the second output gear 9, and both shift members 29 are fixed by the shift fork 30 to the fixed portion 2 a on the inner surface of the transmission case 2.
The fourth transmission shaft 39 supporting the left and right fourth gears 28 and the second output gear 9 engaging with the fourth gear 28 are fixed. Therefore, in this state, for example, when the friction clutch RC is pressed and operated by the left side gear 12, the braking is applied to the left traveling device 4 and the left turn can be performed.

Next, when the switching lever 32 is operated from the pivot turning position to the pivot turning position and the third transmission shaft 24 is further slid to the left in the drawing, the left and right shift members 29 are separated from the fixed portion 2a. The left and right second gears 11 mesh with the left and right third gears 27. In this state, the power of the third transmission shaft 24 is transmitted to the left and right second output gears 9 in the reverse rotation state via the third gear 27, the fourth transmission shaft 39, and the fourth gear 28. Therefore, for example, when the left side gear 12 is separated from the first output gear 7 and the second clutch RC is pressed and operated by the pressing portion 17 of the left side gear 12, the reverse rotation power of the left second output gear 9 causes the left traveling device to rotate. 4 and a left turn can be performed.

Next, the sliding operation structure of the left and right side gears 12 will be described. As shown in FIGS. 4 and 3, an operation arm 20 for sliding the left and right side gears 12 is provided.
And a hydraulic cylinder 33 for swinging the hydraulic cylinder 33. The hydraulic cylinder 33 is provided with a spring (not shown) for urging the hydraulic cylinder 33 toward the contraction side. And the pump 34
Is supplied to a swing control valve 35 of an electromagnetic operation type for the hydraulic cylinder 33. Then, the side gear 12 separates from the first output gear 7 (the side clutch FC
When the hydraulic cylinder 33 is extended until the friction clutch RC moves to a position where the friction clutch RC is not pressed and operated,
A drain oil passage 36 is provided for draining hydraulic oil from the hydraulic cylinder 33 and stopping the hydraulic cylinder 33 at that position. Further, a variable relief valve 37 is provided in the drain oil passage 36.

Next, the operation of the swing control valve 35 and the variable relief valve 37 will be described. The state shown in FIGS. 4 and 3 is a straight traveling state in which the left and right side gears 12 mesh with the first output gear 7. In this state, for example, when the operation lever 40 is operated to the first turning position L1 on the left, only the turning control valve 35 is switched to supply the hydraulic oil to the left hydraulic cylinder 33, and the left side gear 12 is moved to the left in the drawing. Sliding away from the first output gear 7 (side clutch FC is disengaged).

In this case, the drain oil passage 36 opens at the neutral position before the left side gear 12 presses the friction clutch RC, the hydraulic oil flows out of the variable relief valve 37, and the left side gear 12 stops at the neutral position. is there. This is a state in which transmission to the left traveling device 4 has been cut off. This allows
The aircraft slowly turns to the 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 position, and the left friction clutch RC is completely engaged. Operated. In this case, as shown in FIG. 3, if the third transmission shaft 24 is slid rightward on the paper surface, the left traveling device 4 is driven to rotate forward at a low speed and can make a gentle turn. When the operating lever 40 is located between the first and second turning positions L1 and L2 on the left, the hydraulic oil is drawn from the hydraulic cylinder 33 from the above-described state,
The pressing force on the friction clutch RC is reduced. As a result, the second clutch RC slips, and the low-speed forward rotation speed of the left traveling device 4 can be changed.

Next, in a state where the switching lever 32 is operated to the pivot position to engage the shift member 29 of the third transmission shaft 24 with the fixed portion 2a of the transmission case 2, the operation lever 4
When 0 is operated to the second turning position L2 on the left, braking is applied to the left traveling device 4 to perform a pivot turn. Further, when the operating lever 40 is operated between the left first turning position L1 and the second turning position L2, the pressing force on the second clutch RC is changed, and the control of the left traveling device 4 is performed in the same manner as described above. The power can be changed.

Then, the switching lever 32 is operated to the super pivot position to move the second gear 11 of the third transmission shaft 24 to the third gear 2.
When the operation lever 40 is operated to the second turning position L2 on the left in the state of being engaged with 7, the left traveling device 4 is driven to rotate in the reverse direction, so that the super pivot can be performed. Further, the left first turning position L1 and the second
When the operating lever 40 is operated between the turning position L2 and the pressing force applied to the friction clutch RC, the reverse rotation speed of the left traveling device 4 can be changed in the same manner as described above. The above operation is similarly performed at the right first turning position R1 and the second turning position R2.

Next, a description will be given of a shift lever 41 for shifting operation of the gear transmission 31 shown in FIG. 3, and a relationship between the shift lever 41 and the side clutch FC. As shown in FIGS. 1 and 2, a support member 42 is swingably supported around a horizontal axis P1 of the control unit, and a speed change lever 41 is fixed to the support member 42 and fixed to the support member 42. The operating arm 43 and the shift gear 3 of the gear transmission 31 shown in FIG. 3 are mechanically interlocked by an interlocking mechanism 44.

A balance-like hook member 45 is swingably supported around the horizontal axis P2 of the shift lever 41. On the other hand, a lock plate 48 having five sets of locking holes 48a is fixed to the control unit. Then, a push button 46 provided on the upper end of the shift lever 41 (corresponding to a manual operation tool)
And the hook member 45 are linked by a link rod 47. When the push button 46 is pushed upward in the drawing, the hook member 45 separates from the locking hole 48a of the lock plate 48, and when the hand is released from the push button 46, the hook Member 45
Is engaged in the locking hole 48a of the lock plate 48, and the shift lever 41 is locked.

The state shown in FIG. 2 is a state in which the hook member 45 is engaged in the center locking hole 48a, and the shift lever 41 is engaged with the shift gear 3 in FIG.
Is locked. Then, when the shift lever 41 is operated at the position of the locking hole 48a at the left end or the right end in FIG. 2, the shift gear 3 in FIG. 3 meshes with the low speed gear 25 or the first high speed gear 22. The reason why the shift lever 41 is locked at each shift position is to prevent the shift gear 3 from falling out of each gear during traveling.
A locking hole 4 between the center of FIG. 2 and the right and left ends of the drawing.
The position 8a is a neutral position where the shift gear 3 in FIG. 3 does not mesh with any gear.

As shown in FIG. 1 and FIG.
Is provided with a contact-type sensor 49. When the push button 46 is pressed, the lower end of the link rod 47 separates from the sensor 49, and when the hand is released from the push button 46, the lower end of the link rod 47 contacts the sensor 49. It is configured to be. On the other hand, as shown in FIG. 4, a normally-open electromagnetically operated on-off valve 51 is provided in the oil discharge passage 50 of the turning control valve 35.

With the above structure, as shown in FIG. 2, the shift operation is performed from the state where the shift lever 41 is locked in the central locking hole 48a (the shift gear 3 in FIG. 3 is engaged with the middle speed gear 8). In this case, first, the operator presses the push button 46 while grasping the upper end of the shift lever 41. As a result, the lower end of the link rod 47 is separated from the sensor 49, and the hook member 45 is inserted through the locking hole 48a of the lock plate 48.
Comes out.

When such an operation is detected by the sensor 49, the turning control valve 35 in FIG. 4 is operated to the neutral position shown in FIG. 4, and the on-off valve 51 is closed. In this case, if the variable relief valve 37 has been closed, the variable relief valve 37 is opened. In this state, since the hydraulic oil from the pump 34 is supplied to the left and right hydraulic cylinders 33, the left and right hydraulic cylinders 33 are extended and stopped at the position where the drain oil passage 36 is opened.

As described above, the left and right side gears shown in FIG. 3 are simultaneously disengaged from the first output gear 7 and do not press the friction clutch RC, that is, the left and right side clutches FC are disengaged. is there. In this state, the operator operates the transmission lever 41 to perform the transmission operation of the gear transmission 31. When the transmission operation is completed, the operator releases his / her hand from the transmission lever 41 to engage the hook member 45 into the locking hole 48a. Then, the shift lever 41 is locked at the shift position after the shift operation.

When the lower end of the link rod 47 comes into contact with the sensor 49 by performing the above operations, the opening / closing valve 51 shown in FIG. 4 is opened and the turning control valve 35 is operated to the right or left turning position before the gear shifting operation. Or remain in the neutral position of FIG. As a result, the right or left side clutch FC is engaged again, or the left and right side clutches FC remain disengaged.

In the claims of the utility model registration, reference numerals are written 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 longitudinal sectional front view of the vicinity of a shift lever of a gear transmission.

FIG. 2 is a side view of the vicinity of a shift lever of the gear transmission.

FIG. 3 is a schematic diagram showing a structure inside a mission case.

FIG. 4 is a hydraulic cylinder for sliding operation of a side gear;
Hydraulic circuit diagram showing a swing control valve, an on-off valve, etc.

[Explanation of symbols]

 Reference Signs List 4 left and right traveling devices 31 gear transmission 41 transmission lever for gear transmission 46 artificial operation tool M continuously variable transmission FC side clutch

Continuation of front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B60K 20/00-20/08 F16H 61/26

Claims (1)

(57) [Scope of request for utility model registration] 1. A continuously variable transmission (M) for transmitting power from an engine, a stepped gear transmission of a gearshift type (3).
1) and a transmission lever (41) for shifting operation of the gear transmission (31) while transmitting to each of the left and right traveling devices (4) via a pair of left and right side clutches (FC). And the left and right side clutches (FC)
A traveling speed change structure of a working vehicle provided with a manual operation tool (46) capable of simultaneously turning off the vehicle.