JPH0522148U - Work vehicle traveling speed change structure - Google Patents

Abstract

(57) [Abstract] [Purpose] A structure for transmitting power from an engine to each of the left and right traveling devices through a continuously variable transmission, a gear shift type stepped gear transmission, and a pair of left and right side clutches. In the traveling speed change structure of the work vehicle described above, the speed change operation of the gear transmission by the speed change lever can be lightly performed at the time of stopping and traveling. [Structure] Gear shift lever 41 for gear shift operation of gear transmission
Manipulation tool 4 that can be operated by disengaging the left and right side clutches
6 is provided. As a result, the manual operation tool 46 is operated when the shift lever 41 is operated to disengage the left and right side clutches, and the surface pressure generated on the occlusal surface of the shift gear in the gear transmission is reduced.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention is configured to transmit power from an engine 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 (for turning). The present invention relates to a traveling speed change structure of a working vehicle.

[0002]

[Prior Art]

 An example of the above-mentioned work vehicle is an agricultural combine, and a shift lever for operating the continuously variable transmission and a shift lever for operating the gear transmission are separately provided. There are two types of continuously variable transmissions: hydrostatic type and belt type using split pulley.These continuously variable transmissions can be operated directly by the shift lever without disengaging the clutch of the traveling system. Is. The gear shifting operation during work traveling or road traveling is mainly performed by gear shifting operation of the continuously variable transmission. On the other hand, the gear transmission has the character of an auxiliary transmission with respect to the continuously variable transmission described above, and is used when changing the entire shift range of the continuously variable transmission to the high speed side or the low speed side. I often operate. As a result, the gear transmission is often operated when the continuously variable transmission is stopped at the neutral position.

In this case, if the continuously variable transmission is operated to a neutral position where power is not transmitted, the same state as when the clutch of the traveling system is disengaged can be obtained. The gear transmission can be directly operated by the gear shift lever without the need for a turning operation. Further, it is possible to directly shift the gear transmission by the shift lever without disengaging the clutch of the traveling system even during traveling.

[0004]

[Problems to be solved by the device]

 In the continuously variable transmission used for the work vehicle described above, the range of the neutral position where power is not transmitted is generally very narrow. Therefore, even if the operator intends to stop the aircraft by operating the speed change lever of the continuously variable transmission to the neutral position, the continuously variable transmission itself is not in the completely neutral position, and the continuously variable transmission changes gears. There is a case where a slight amount of power flows to the device and it stops due to the resistance from the ground on the traveling device. In such a case, the surface pressure at the contact surface between the shifting gear and the transmission gear of the gear transmission is extremely high due to the power from the continuously variable transmission. Therefore, even if the gear shift lever of the gear transmission is operated in this state, the shift gear is difficult to come off from the transmission gear due to the above-mentioned high surface pressure, and the gear shift operation becomes heavy. Also, even if you try to operate the gear shift lever of the gear transmission during traveling, the surface pressure at the shift gear of the gear transmission increases due to the power from the continuously variable transmission and the traveling resistance applied to the traveling device. The gear shift lever is heavy to operate. Such a state becomes remarkable when the traveling resistance applied to the traveling device becomes extremely large such as when turning. An object of the present invention is to configure a gear transmission so that a gear shift operation can be performed lightly when the airframe is stopped and running.

[0005]

[Means for Solving the Problems]

 A feature of the present invention is that the traveling speed change structure for a work vehicle as described above is configured as follows. That is, the power from the engine is configured to be transmitted to each of the left and right traveling devices via the continuously variable transmission, the gear transmission of a gear shift type having a step, and the pair of left and right side clutches. The gear shift lever for gear shifting is equipped with an artificial operation tool that can be operated by cutting the left and right side clutches.

[0006]

[Action]

 With the above-described structure, when the gear shift operation for the gear transmission is performed, the left and right side clutches are disengaged by operating the manual operation tool provided on the gear shift lever. By doing so, the gap between the gear transmission and the traveling device is disconnected, and the lower side portion of the gear transmission is brought into a free rotation state. In such a state, even if power is transmitted from the continuously variable transmission on the right side to the gear transmission, the surface pressure generated in the shift gear in the gear transmission becomes small. Accordingly, the sliding operation of the shift gear by the shift lever, that is, the shift operation of the gear transmission can be performed lightly. In this case, it is necessary to operate the manual operation tool for the side clutch in addition to the gear shift operation by the gear shift lever, but since this manual operation tool is provided on the gear shift lever itself, the manual operation tool is operated with the hand holding the gear shift lever. It becomes possible to do. Therefore, the operability does not deteriorate.

[0007]

[Effect of the device]

 As described above, by operating the left and right side clutches to disengage during gear shifting operations, the gear shifting lever can be operated lightly both when stopped and while traveling, improving gear shifting operability. I was able to do it. Further, since the speed change lever itself is provided with the manual operation tool for the side clutch, it is possible to minimize deterioration of the operability due to the manual operation tool.

[0008]

【Example】

 Embodiments of the present invention will be described below with reference to the drawings. Fig. 3 shows the structure inside the mission case 2 of the traveling system of the combine, which is one of the work vehicles, in which the power from the engine (not shown) uses a belt transmission mechanism (not shown) equipped with a tension clutch. It is transmitted to the input pulley 16 of the hydrostatic continuously variable transmission M via. Power from the output shaft 1 of the continuously variable transmission M is transmitted from the first transmission shaft 14 to the mowing section (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. A first high speed gear 22 is fitted onto the second transmission shaft 21 so as to be rotatable relative to the second transmission shaft 21, and a 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 by a spline structure, and the first and second high speed gears 22 and 23 are in mesh with each other. As a result, the power can be shifted to three stages of high, medium and low by slidingly operating the shift gear 3 and engaging the first high speed gear 22, the medium speed gear 8 and the low speed gear 25. Is transmitted to the first output gear 7 that meshes with. As described above, the gear transmission 31 (corresponding to a traveling gear transmission) is configured.

The right and left side gears 12 are relatively rotatably fitted over the support shaft 6 supporting the first output gear 7, and the input gears 18 of the left and right axles 5 are constantly meshed 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 articulated manner, and the convex engagement portion 13 of the side gear 12 is connected to the first output gear 7. By engaging them, the forward rotation power is transmitted to the left and right crawler type traveling devices 4. Further, the spring 19 biases the side gear 12 toward the first output gear 7 side (the side on which the side clutch FC enters).

A pair of second output gears 9 are externally fitted to the left and right 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 portion so that the third transmission shaft 24 can be slid to the left and right. In this case, since the low speed gear 25 and the middle speed gear 8 are positioned by the sleeve 26, the positions of the low speed gear 25 and the middle speed gear 8 do not change even if the third transmission shaft 24 is slid.

In the state shown in FIG. 3, the third transmission shaft 24 is slid rightward on the paper surface, and the second gears 11 on the left and right of the third transmission shaft 24 are connected to the second output gears 9 on the left and right. It is in a directly occluded state. As a result, the normal rotation power that is lower than the normal 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 operates at a lower speed than the right traveling device 4. It is driven in the normal direction, and the aircraft slowly turns to the left due to the speed difference between the left and right traveling devices 4.

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

With the above structure, when the switching lever 32 is operated from the gentle turning position of FIG. 3 to the ground turning position and the third transmission shaft 24 is slid to the left side of the drawing, the second gear 11 moves to the second output position. The shift fork 30 separates the shift gears 29 from the force gear 9, and both shift members 29 engage with the fixed portion 2a on the inner surface of the transmission case 2 to support the left and right fourth gears 28 and the fourth transmission shaft 39 and the fourth gear. The second output gear 9 that engages with 28 is fixed. Therefore, in this state, for example, when the friction clutch RC is pressed and operated by the left side gear 12, braking is applied to the left traveling device 4 and turning to the left is possible.

Next, when the switching lever 32 is operated from the pivot turning position to the super pivot turning position and the third transmission shaft 24 is further slid to the left side of 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 runs to the left. It is transmitted to the device 4 and super-spot turning can be performed to the left.

Next, the sliding operation structure of the left and right side gears 12 will be described. As shown in FIGS. 4 and 3, an operating arm 20 for sliding operation of the left and right side gears 12 and a hydraulic cylinder 33 for swinging the operating arm 20 are provided, and the hydraulic cylinder 33 is urged toward the contracting side. A spring (not shown) is installed inside. The hydraulic oil from the pump 34 is supplied to the electromagnetically controlled swing control valve 35 for the hydraulic cylinder 33. When the side gear 12 separates from the first output gear 7 (the side clutch FC is in the disengaged state) and the hydraulic cylinder 33 extends until it moves to a position where the friction clutch RC is not pressed and operated, the hydraulic cylinder 33 operates from this hydraulic cylinder 33. A drain oil passage 36 is provided to drain oil and stop the hydraulic cylinder 33 at that position. Further, the drain oil passage 36 is provided with a variable relief valve 37.

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. If the operating lever 40 is operated to the left first turning position L1 from this state, for example, only the turning control valve 35 is switched and operating oil is supplied to the left hydraulic cylinder 33, so that the left side gear 12 moves to the left side of the drawing. Sliding away from the first output gear 7 (side clutch FC disengaged).

In this case, since the drain oil passage 36 opens at the neutral position before the left side gear 12 presses the friction clutch RC, the hydraulic oil escapes from the variable relief valve 37, and the left side gear 12 stops at the neutral position. is there. This is the state in which the transmission to the left traveling device 4 is cut off. As a result, the aircraft slowly turns to the left.

When the operating lever 40 is operated to the second left 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 moved. Entered and 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 normally driven at a low speed to make a gentle turn. When the operating lever 40 is located between the left first and second turning positions L1 and L2, the hydraulic oil is drained from the hydraulic cylinder 33 from the above-mentioned state, and the pressing force on the friction clutch RC is weakened. .. As a result, the second clutch RC slips, and the low forward speed of the left traveling device 4 can be changed.

Next, in a state in which the switching lever 32 is operated to the pivot turning position and the shift member 29 of the third transmission shaft 24 is engaged with the fixed portion 2a of the mission case 2, the operation lever 40 is moved to the left second position. When the vehicle is operated to the turning position L2, the left traveling device 4 is braked and the turning can be carried out. 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 left running device 4 of the left running device 4 is changed as described above. The braking force can be changed.

Then, in a state in which the switching lever 32 is operated to the super-position turning position and the second gear 11 of the third transmission shaft 24 is engaged with the third gear 27, the operation lever 40 is moved to the left second turning position. When it is operated to the position L2, the left traveling device 4 is driven in the reverse direction, and super-spot turning can be performed. 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 friction clutch RC is changed, and the reverse rotation speed of the left traveling device 4 is changed as described above. Can be changed. The above operation is similarly performed at the right first turning position R1 and the second turning position R2.

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

A balance-shaped hook member 45 is swingably supported around the horizontal axis P2 of the speed change lever 41. On the other hand, a lock plate 48 having five sets of locking holes 48a is fixed to the control portion. A push button 46 (corresponding to an artificial operation tool) provided on the upper end of the speed change lever 41 and a hook member 45 are linked by a link rod 47. When the push button 46 is pushed upward on the paper surface, the hook member is pushed. When 45 is separated from the locking hole 48a of the lock plate 48 and the hand is released from the push button 46, the hook member 45 is engaged with the locking hole 48a of the lock plate 48 and the transmission lever 41 is locked.

The state shown in FIG. 2 is a state in which the hook member 45 is engaged in the central locking hole 48 a, and the shift lever 41 is locked when the shift gear 3 in FIG. 3 meshes with the middle speed gear 8. It is in a state of being crushed. When the shift lever 41 is operated to the position of the locking hole 48a at the left end or the right end in the drawing 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 coming off from each gear during traveling. The position of the locking hole 48a between the center of FIG. 2 and the right and left ends of the drawing is the neutral position where the shift gear 3 of FIG. 3 does not engage with any gear.

As shown in FIGS. 1 and 2, a contact-type sensor 49 is provided on the support member 42, and when the push button 46 is pushed, the lower end of the linking rod 47 is separated from the sensor 49. When the hand is released from 46, the lower end of the linking rod 47 contacts the sensor 49. 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 meshes with the middle speed gear 8). In this case, first, the operator grasps the upper end of the speed change lever 41 and pushes the push button 46 to operate. As a result, the lower end of the linking rod 47 is separated from the sensor 49, and the hook member 45 is pulled out from the locking hole 48a of the lock plate 48.

When such an operation is detected by the sensor 49, the turning control valve 35 shown in FIG. 4 is operated to the neutral position shown in FIG. 4 and the opening / closing valve 51 is closed. In this case, if the variable relief valve 37 is closed, the variable relief valve 37 is opened. In this state, the hydraulic oil from the pump 34 is supplied to the left and right hydraulic cylinders 33, so that the left and right hydraulic cylinders 33 extend and stop at the position where the drain oil passage 36 opens.

As described above, in the above-described state, the left and right side gears shown in FIG. 3 are separated from the first output gear 7, and the friction clutch RC is not pressed, that is, the left and right side clutches FC are disengaged. is there. In this state, the operator operates the gear shift lever 41 to perform the gear shift operation of the gear transmission 31. When the gear shift operation is completed, the operator releases the gear shift lever 41 and engages the hook member 45 with 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 linkage rod 47 comes into contact with the sensor 49 by performing the above operation, the opening / closing valve 51 of FIG. 4 is opened and the swing control valve 35 is moved to the right or left turning position before the gear shifting operation. It is operated or remains in the neutral position of FIG. As a result, the right or left side clutch FC is turned on or operated again, or the left and right side clutches FC are disengaged and remain in operation.

In the claims of the utility model, reference numerals are given for convenience of comparison with the drawings, but the present invention is not limited to the configuration of the accompanying drawings by the entry.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional front view near a gear shift lever of a gear transmission.

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

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

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

[Explanation of symbols]

 4 Left and right traveling devices 31 Gear transmission 41 Gear shift lever for gear transmission 46 Manual operation tool M Continuous transmission FC Side clutch

Claims (1)

[Scope of utility model registration request] 1. A continuously variable transmission (M) for transmitting power from an engine, and a gear transmission (3) having a gear shift type and a plurality of steps.
1) and the left and right side clutches (FC) to transmit to each of the left and right traveling devices (4), and the speed change lever (41) for speed change operation of the gear speed change device (31). The left and right side clutches (FC)
A traveling speed change structure for a work vehicle, which is provided with an artificial operation tool (46) that can be turned off.