JPH09170656A - Traveling speed change structure of working vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structure which can attain high operationability and simple speed changing operation, in the traveling speed change structure of a working vehicle provided with the first transmission device of hydraulic clutch type and the second transmission device of gear shift type. SOLUTION: The supplying and discharging operations of hydraulic oil are provided for the hydraulic clutch of the first transmission device, and the speed changing operation of the first transmission device, and a speed change control valve is provided at a transmission case to conduct the speed changing operation of the first transmission device. A manually operated device 26 and a speed change control valve are interlockingly-connected through the first linkage mechanism 25. The shift member of the second transmission device and the first linkage mechanism 25 are interlockingly-connected through the second linkage mechanisms 16b, 28a, 28b near the speed change control valve.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a traveling speed change structure for a work vehicle.

[0002]

2. Description of the Related Art In a work vehicle such as a combine, a plurality of hydraulic clutches for transmission of speed change (as shown in FIGS. 4 and 5 of the publication, as disclosed in JP-A-62-177340). 20a to 20c) in parallel, and a hydraulic clutch type first transmission device (fourth publications in the above publications) that performs a plurality of gear shift operations by selectively supplying and discharging hydraulic oil to the hydraulic clutch. 17) in the figure, and a gear shift type second transmission device (16 in FIG. 4 of the publication) for performing a shift operation of a plurality of stages by operating a shift member.
In some transmissions, the first and second transmissions are arranged in series in the mission case. By arranging the first and second transmissions in series in this way, a multi-stage gear shift operation becomes possible.

[0003]

The work vehicle described above is provided with a shift control valve for performing a shift operation by supplying / discharging hydraulic oil to / from the hydraulic clutch of the first transmission, and the shift control valve is artificially operated. A first gearshift lever (corresponding to an artificial operation tool) that is operated manually is provided. Further, a second gearshift lever (corresponding to a human-operated operation tool) for performing a gearshift operation by artificially operating the shift member of the second transmission is provided.

If the first and second speed change levers are provided separately in this way, it is necessary to change the holding of the first and second speed change levers when performing a multi-speed shift operation by the first and second speed change devices. Therefore, there is room for improvement in terms of operability. SUMMARY OF THE INVENTION It is an object of the present invention to obtain a simple gear shift operation structure with good operability in a traveling gear shift structure of a work vehicle including a hydraulic clutch type first gear shift device and a gear shift type second gear shift device.

[0005]

[Means for Solving the Problems]

[I] According to the feature of claim 1, when the manual operation tool is operated, the shift control valve is operated via the first linkage mechanism, and
The gear shift operation of the transmission is performed, and the operation of the first linkage mechanism at the time of this operation is transmitted to the shift member of the second transmission via the second linkage mechanism, and the shift member is operated. Gear shifting operation is performed. In this way, the speed change operation of the first and second speed change devices can be performed by one artificial operation tool.

In this case, since the transmission case in which the first and second transmissions are installed is provided with the shift control valve,
The shift member and the shift control valve of the second transmission are close to each other. Accordingly, if the second linkage mechanism is arranged over the portion near the shift control valve and the shift member of the second transmission in the first linkage mechanism, the second linkage mechanism may be short and small.

When the first transmission of the hydraulic clutch type and the second transmission of the gear shift type are provided as described above,
The operation of the shift control valve in the first transmission is easier than the operation of the shift member of the second transmission. Thus, for example, the first transmission is operated over the entire range at the low speed position of the second transmission, the second transmission is then operated at the medium speed position, and the first transmission is operated over the entire range. As in the case of shifting operation, it is often the case that a mode in which a multi-stage shifting state is obtained by repeatedly shifting the hydraulic clutch type first transmission device over the entire range is adopted. Therefore, based on the operation of the first linkage mechanism (shift control valve), the shift member (second
If the transmission is configured to operate mechanically, the first
Linkage mechanism (shift control valve) and shift member (second transmission)
By providing the second linking mechanism for linking with and with a measure such as having a simple interchangeable structure, it is possible to easily deal with the mode in which the first transmission of hydraulic clutch type is repeatedly operated over the entire range.

[II] According to the feature of claim 2, for example, as shown in FIGS. 5 and 6, when the manual operation tool 26 is operated, the first operation member 25 is oscillated around the axis P1, The shift control valve is operated by the swing motion of the first operation member 25, and the shift operation of the first transmission is performed. With the swinging motion of the first operating member 25, the second operating members 28, 28a, 28b are operated via the cam portion 30, and the linkage mechanism 1 is operated.
The gear shift operation of the second transmission is performed via 6, 29.
As described above, the shift operation of the first and second transmissions can be performed by the single manual operation tool 26.

In this case, since the transmission case in which the first and second transmissions are installed is provided with the shift control valve,
The shift member and the shift control valve of the second transmission are close to each other. As a result, the first operation member for operating the shift control valve and the second member over the shift member of the second transmission are provided.
If the operation member and the linkage mechanism are arranged, the second operation member and the linkage mechanism may be short and small.

For example, as shown in FIG. 5, the first operating member 2
When 5 is configured to be rocked around the axis P1,
The first operating member 25 is a relatively long member extending along the radial direction of the axis P1 (vertical direction in the plane of FIG. 5). Therefore, if the second operating member 28, 28a, 28b is configured to be operated along the extending direction of the first operating member 25 by the cam portion 30 of the first operating member 25, the second operating member 28, 28a. , 28b can be set to be relatively large. Thus, when operating the shift member of the second transmission, even if the operating range of the shift member is relatively large, the shift member can be accurately moved by the second operating members 28, 28a, 28b without insufficient operating range. Can be operated.

When the hydraulic clutch type first transmission and the gear shift type second transmission as described above are provided,
The operation of the shift control valve in the first transmission is easier than the operation of the shift member of the second transmission. Thus, for example, the first transmission is operated over the entire range at the low speed position of the second transmission, the second transmission is then operated at the medium speed position, and the first transmission is operated over the entire range. As in the case of shifting operation, it is often the case that a mode in which a multi-stage shifting state is obtained by repeatedly shifting the hydraulic clutch type first transmission device over the entire range is adopted. Therefore, based on the operation of the first operation member (shift control valve) as in the second aspect, the shift member (second
If the transmission is configured to operate mechanically, the first
Operation member (shift control valve) and shift member (second transmission)
By providing the second operating member or the linkage mechanism for linking with and with a measure such as having a simple interchangeable structure, it is possible to easily cope with the mode in which the first transmission device of the hydraulic clutch type is repeatedly operated over the entire range. it can.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION

(1) FIG. 1 shows the inside of a mission case 1 for traveling of an agricultural combine, which is an example of a work vehicle, in which power from an engine (not shown) is transmitted through a transmission belt (not shown). It is transmitted to the input pulley 2 of the transmission case 1 and is transmitted to the left and right crawler traveling devices 6 via the second transmission 4 of the gear shift type, the first transmission 3 of the hydraulic clutch type, and the side clutch 5. Second transmission 4
The power branched from is transmitted to the mowing unit (not shown) via the gear transmission 7, the output pulley 8 and the mowing clutch (not shown).

Next, the second transmission 4 will be described. As shown in FIG. 1, the input shaft 9 to which the input pulley 2 is fixed
On the other hand, the transmission shaft 10 is arranged, and the low speed gear 11 and the high speed gear 12 which are fitted onto the input shaft 9 so as to be rotatable relative to each other mesh with the low speed gear 13 and the high speed gear 14 fixed to the transmission shaft 10. A shift member 17 is slidably fitted to the input shaft 9 between the low speed gear 11 and the medium speed gear 12 in a spline structure.

With the above structure, when the shift member 17 is engaged with the low speed gear 11 (low speed position L), the power of the input shaft 9 is transmitted from the transmission shaft 10 to the first transmission 3 in the low speed state, and the shift member 17 is moved. Is engaged with the high speed gear 12 (high speed position H), the power of the input shaft 9 is transmitted from the transmission shaft 10 to the first transmission device 3 in a high speed state, and the second transmission device 4 operates in two high and low stages. You can shift gears.

Next, the first transmission 3 will be described. As shown in FIG. 1, a hydraulic multi-plate forward first speed clutch 19
A forward two-speed clutch 20 (corresponding to a hydraulic clutch), a third forward speed clutch 21 (corresponding to a hydraulic clutch), and a reverse clutch 22 are arranged in parallel with the transmission shaft 10. As a result, by selectively supplying hydraulic oil to the first forward speed to the reverse clutches 19 to 22 to perform a transmission operation, a shift operation of three forward steps and one reverse step can be performed.

(2) Next, the structure of the shift operation of the first transmission 3 will be described. As shown in FIGS. 2, 3 and 4, the first
The transmission case 1 is internally provided with a rotary type speed change control valve 23 for supplying / discharging hydraulic oil to / from the first forward speed to the reverse clutches 19 to 22 of the transmission 3. The shift control valve 23 includes a neutral position N, a first forward speed position F1 to a sixth forward speed position F6, a reverse first speed position R1 and a reverse second speed position R2, and a piston 24 is provided inside a spool 24 formed in a cylindrical shape. 31a
And an accumulator 31 composed of a spring 31b
Is provided.

The spool 24 of the shift control valve 23 is shown in FIG.
As shown in 4, 7, (a), (b), (c), and (d), the first, second, and third speed forward clutches 19, 20, 21 are used to supply and discharge hydraulic fluid and communicate with the accumulator 31. And second and third hydraulic oil holes 24d and 24e, which are used to supply and discharge hydraulic oil to and from the reverse clutch 22, communicate with the accumulator 31, and third and fourth hydraulic oil holes 24g and 24h, and first to discharge hydraulic oil from the accumulator 31. , 2, 3 drain holes 24i,
24 j, 24 k, first recess 24 m for discharging hydraulic oil of first forward speed-reverse clutches 19-22, second recess 24 n communicating with operation cylinder 33 (see FIG. 2) for transmitting and cutting the cutting clutch, and pump 32. (See FIG. 2) Third recess 24o to which hydraulic oil is supplied, fifth hydraulic oil hole 24p that supplies hydraulic oil from pump 32 to accumulator 31,
A lateral groove 24q connected to the second recess 24n is formed. As shown in FIG. 2, the lubricating oil in the transmission case 1 is sucked into the pump 32 through the filter 15 as the working oil, and the working oil from the pump 32 and the third recess 24o of the spool 24 of the shift control valve 23 and It is supplied to the fifth hydraulic oil hole 24p or the groove 24q.

As shown in FIGS. 5 and 3, the shift control valve 2
The gear portion 24 a at the end portion of the spool 24 of No. 3 projects outside the mission case 1. A fan-shaped operation gear 25 (corresponding to a first linkage mechanism and a first operation member) is swingably supported around a horizontal axis P1 (corresponding to the axis) of the upper portion of the transmission case 1, and the operation gear 25 A gearshift lever 26 (corresponding to a manual operation tool) is fixed to the gearshift lever 26, and the operation gear 25 meshes with the gear portion 24a of the spool 24.

With the above structure, when the speed change lever 26 is operated in the left-right direction on the paper surface of FIG. 5, the spool 24 is rotated by the operation gear 25, and the spool 24 is in the neutral position N and the first forward speed position F1 (first forward speed). Clutch 19 transmission operation, forward 2nd speed position F2 (forward 2nd speed clutch 20 transmission operation), 3rd forward speed position F3 (forward 3rd speed clutch 21 transmission operation), 4th forward speed position F4 (forward 1st speed clutch 19) 5 forward gear position F5 (2nd forward gear clutch 20)
6 forward speed position F6 (3 forward speed clutch 2
1 is a transmission operation), and a reverse movement first speed position R1 (reverse movement clutch 22 is transmission operation) and a reverse second speed position R2 (reverse movement clutch 22 is a transmission operation).
The transmission 3 is repeatedly operated over the entire range.

(3) Next, the structure of the shifting operation of the second transmission 4 will be described. As shown in FIG. 6, a support shaft 27 is fixed in the transmission case 1, and a shift fork 29 (corresponding to a second linkage mechanism and a linkage mechanism) that engages with a shift member 17 of the second transmission 4 is a support shaft. 27 is slidably fitted over the shift lever 27 and the shift fork 29 is moved to the low speed position L.
And a ball detent mechanism 29a for holding at the high speed position H
Is provided on the shift fork 29. An operation shaft 16 (corresponding to a second linkage mechanism and a linkage mechanism) is rotatably supported around a horizontal axis P2 of the mission case 1, and a first arm 16a fixed to the operation shaft 16 is a shift fork 2.
The arc-shaped toggle spring 18, which is engaged with the operating shaft 16 and holds the operating shaft 16 at the low speed position L and the high speed position H, is
6 is attached to the third arm 16c.

As shown in FIGS. 5 and 6, the boss portion 28 (corresponding to the second linkage mechanism and the second operating member) is rotatably supported around the horizontal axis P3 of the mission case 1 and is attached to the boss portion 28. The fixed first arm 28a (corresponding to the second operating member) is engaged with the second arm 16b (corresponding to the second operating member) fixed to the operating shaft 16. A bent long cam hole 30 (corresponding to a cam portion) is formed in the operation gear 25, and the second arm 28b fixed to the boss portion 28 is formed.
Roller 28 c is inserted into the cam hole 30 of the operation gear 25.

With the above-mentioned structure, the speed change lever 26 is shown in FIG.
The horizontal axis P1 by operating the operating gear 25 in the horizontal direction of
When the swinging operation is performed around, the spool 24 is rotated by the swinging operation of the operation gear 25, and the forward side of the first transmission 3 is repeatedly shifted over the entire range. At the same time, the cam hole 30 of the operation gear 25 causes the boss portion 28 (first
And the second arms 28a and 28b) are oscillated around the horizontal axis P3 (corresponding to a state in which they are operated along the extending direction of the operation gear 25), and the operation shaft 16 (first and second arms 16).
a, 16b) is oscillated around the horizontal axis P2, the shift member 17 is operated by the shift fork 29, and the second transmission 4 is shifted to the low speed position L and the high speed position H.

(4) As described in (2) and (3) above,
While the second transmission 4 is operated to shift to the low speed position L and the high speed position H, the forward 1, 2 and 3 speed clutches 19, 20 and 21 of the first transmission 3 are repeatedly operated to be transmitted twice. The first and second transmissions 3 and 4 can perform a shift operation in six forward gears, and can similarly perform a shift operation in two reverse gears. Next, such first and second transmissions 3,
The shift relationship of No. 4 will be described.

(4) -1 In the state shown in FIG. 8, the speed change lever 26 and the speed change control valve 23 are set.
Is in a state in which the spool 24 is being operated to the neutral position N, and at the neutral position N, the first forward speed-reverse clutch 19-
The hydraulic oil 22 is discharged from the first recess 24m of the spool 24 into the mission case 1 through the first drain port 34, and the hydraulic oil of the accumulator 31 is discharged from the first drain hole 24i of the spool 24 to the second drain port 35. Is discharged to the inside of the mission case 1 via the, and the first forward speed-reverse clutches 19 to 22 are subjected to the transmission interruption operation. The hydraulic oil from the pump 32 is supplied to the operation cylinder 33 via the groove 24q of the spool 24 and the second recess 24n, and the transmission clutch is operated to cut off the transmission.

At the neutral position N, as shown in FIGS. 5 and 6, the cam hole 30 of the operation gear 25 allows the boss portion 2 to move.
8 (first and second arms 28a, 28b) and the operation shaft 16 (first, second, third arms 16a, 16b, 16c) are in the low speed position L, and the shift member 17 of the second transmission 4 is a low speed gear. 11 is engaged, and the second transmission 4 moves to the low speed position L.
The gear is being changed to.

When the speed change lever 26 and the spool 24 are operated from the neutral position N to the first forward speed position F1, the hydraulic oil from the operation cylinder 33 flows from the second recess 24n of the spool 24 to the second drain port as shown in FIG. It is discharged via 35 and the reaping clutch is operated for transmission. At the same time, the hydraulic oil from the pump 32 is transferred to the third recess 2 of the spool 24.
4o, the fifth hydraulic oil hole 24p, the accumulator 31 and the first hydraulic oil hole 24d are supplied to the forward first speed clutch 19, and the pressure of the hydraulic oil is smoothly increased by the action of the accumulator 31 to increase the forward first speed. The clutch 19 is operated for transmission. At the forward first speed position F1, as shown in FIGS. 5 and 6, the cam hole 30 of the operation gear 25 causes the boss portion 28 (first and second arms 28a and 28b) and the operation shaft 16 to move.
The (first, second, third arms 16a, 16b, 16c) are in the low speed position L.

Move the speed change lever 26 and the spool 24 forward 1
When the second forward speed F2 is operated from the second speed F1 in FIG.
As shown in, the hydraulic oil of the first forward speed clutch 19 is gradually discharged through the groove portion 24r of the spool 24, and
The speed clutch 19 is transmission-interrupted, the hydraulic oil is supplied to the forward second speed clutch 20 through the first hydraulic oil hole 24d, the accumulator 31 does not function, and the forward second speed clutch 20 is rapidly transmitted. . At the forward second speed position F2, as shown in FIGS. 5 and 6, the cam hole 30 of the operation gear 25 causes the boss portion 28 (first and second arms 28a, 28).
b), and the operating shaft 16 (first, second, third arms 16a, 1)
6b and 16c) are in the low speed position L.

The speed change lever 26 and the spool 24 are moved forward 2
When operating from the forward speed position F2 to the forward third speed position F3, FIG.
As shown in FIG. 3, the hydraulic oil of the forward second speed clutch 20 is gradually discharged through the groove 24r of the spool 24, and
The speed clutch 20 is transmission-interrupted, the hydraulic oil is supplied to the forward third speed clutch 21 through the first hydraulic oil hole 24d, the accumulator 31 does not function, and the forward third speed clutch 21 is rapidly transmitted. . At the forward third speed position F3, as shown in FIGS. 5 and 6, the cam hole 30 of the operation gear 25 causes the boss portion 28 (first and second arms 28 a, 28
b), and the operating shaft 16 (first, second, third arms 16a, 1)
6b and 16c) are in the low speed position L.

(4) -2 When the transmission lever 26 and the spool 24 are operated from the forward third speed position F3 to the forward fourth speed position F4, as shown in FIG. 12, between the forward third speed and the forward fourth speed positions F3 and F4. Neutral position N
At F, the hydraulic oil of the forward third speed clutch 21 is gradually discharged through the groove 24r of the spool 24, and
The speed clutch 21 is transmission-interrupted, and the hydraulic oil in the accumulator 31 is slightly discharged via the second drain hole 24j of the spool 24 and the second drain port 35.

In this case, as shown in FIG. 5, the gap between the inclined portions 30a and 30b of the cam hole 30 is set to be wider than other portions, and the forward third speed clutch 21 is set as described above. After the transmission cutoff operation, the roller 28c of the second arm 28b rides on the inclined portion 30a of the cam hole 30, and the boss portion 28 (first and second arms 28a, 28
b), and the operating shaft 16 (first, second, third arms 16a, 1)
6b, 16c) is operated from the low speed position L to the high speed position H, the shift member 17 of the second transmission 4 is engaged with the high speed gear 12, and the second transmission 4 is operated to the high speed position H. Then, after that, the forward first speed clutch 19 is operated to be transmitted as described later.

On the contrary, when the transmission lever 26 and the spool 24 are operated from the forward fourth speed position F4 to the forward third speed position F3, after the transmission first speed clutch 19 is similarly disengaged at the neutral position NF, The roller 28c of the second arm 28b is pushed down by the inclined portion 30b of the cam hole 30, and the boss portion 28 (the first and second arms 28b
a, 28b) and the operating shaft 16 (first, second, third arm 1)
6a, 16b, 16c) is operated from the high speed position H to the low speed position L, and the second transmission 4 is operated to shift to the low speed position L. Then, after this, the forward third speed clutch 21 is operated for transmission.

Next, when the shift lever 26 and the spool 24 are operated to the forward fourth speed position F4, the hydraulic oil from the pump 32 is transferred to the third recess 24o of the spool 24, as shown in FIG.
It is supplied to the forward first speed clutch 19 through the fifth hydraulic oil hole 24p, the accumulator 31 and the second hydraulic oil hole 24e, and the pressure of the hydraulic oil is smoothly increased by the action of the accumulator 31, so that the forward first speed clutch 19 Is transmitted. In this case, the second position at the neutral position NF shown in FIG.
The drain hole 24j is formed at the first position at the neutral position N shown in FIG.
The diameter of the drain hole 24i is set smaller than that of the drain hole 24i so that only a small amount of hydraulic oil is discharged from the accumulator 31 at the neutral position NF. When the spool 24 is operated to the fourth forward speed position F4, the first forward clutch 19 I try not to slow down the transmission operation of.

The speed change lever 26 and the spool 24 are moved forward 4
When operating from the fifth speed position F5 to the fifth forward speed position F5, FIG.
As shown in, the hydraulic oil of the first forward speed clutch 19 is gradually discharged through the groove portion 24r of the spool 24, and
The speed clutch 19 is transmission-interrupted, hydraulic oil is supplied to the forward second speed clutch 20 through the second hydraulic oil hole 24e, the accumulator 31 does not function, and the forward second speed clutch 20 is rapidly transmitted. . At the fifth forward speed F5, as shown in FIGS. 5 and 6, the cam hole 30 of the operation gear 25 causes the boss portion 28 (first and second arms 28a, 28
b), and the operating shaft 16 (first, second, third arms 16a, 1)
6b, 16c) is in the high speed position H.

The speed change lever 26 and the spool 24 are moved forward 5
When the forward speed F5 is operated to the sixth forward speed F6,
As shown in FIG. 3, the hydraulic oil of the forward second speed clutch 20 is gradually discharged through the groove 24r of the spool 24, and
The speed clutch 20 is transmission-interrupted, hydraulic oil is supplied to the forward third speed clutch 21 through the second hydraulic oil hole 24e, the accumulator 31 does not function, and the forward third speed clutch 21 is rapidly transmitted. . In the sixth forward speed position F6, as shown in FIGS. 5 and 6, the cam hole 30 of the operation gear 25 causes the boss portion 28 (first and second arms 28a, 28a
b), and the operating shaft 16 (first, second, third arms 16a, 1)
6b, 16c) is in the high speed position H.

(4) -3 When the speed change lever 26 and the spool 24 are operated from the neutral position N to the reverse first speed position R1, the hydraulic oil from the operating cylinder 33 causes the second concave portion 2 of the spool 24 to move as shown in FIG.
4n is discharged through the second drain port 35 and the harvest clutch is operated for transmission. At the same time, the hydraulic oil from the pump 32 is transferred to the third recess 24o of the spool 24, the fifth hydraulic oil hole 24p, the accumulator 31 and the third hydraulic oil hole 2.
It is supplied to the reverse clutch 22 via 4g, the pressure of the hydraulic oil is smoothly increased by the action of the accumulator 31, and the reverse clutch 22 is operated for transmission. At the reverse first speed position R1, as shown in FIGS. 5 and 6, the cam hole 30 of the operation gear 25 causes the boss portion 28 (first and second arms 28, 28
a, 28b) and the operating shaft 16 (first, second, third arm 1)
6a, 16b, 16c) are in the low speed position L.

Move the speed change lever 26 and the spool 24 backward 1
When operating from the reverse speed position R1 to the reverse second speed position R2, FIG.
As shown in, the hydraulic oil of the reverse clutch 22 is discharged via the first recess 24m of the spool 24 and the first drain port 34 before the neutral position NR between the reverse first speed and second reverse positions R1, R2. Then, the reverse clutch 22 is operated to cut off the transmission, and the third clutch of the spool 24 is moved to the neutral position NR.
The hydraulic oil in the accumulator 31 is discharged through the drain hole 24k and the second drain port 35.

In this case, as shown in FIG. 5, the gap between the inclined portions 30c and 30d of the cam hole 30 is set to be wider than the other portions, and as described above, the reverse clutch 22 is operated to interrupt the transmission. After that, the roller 28c of the second arm 28b runs on the inclined portion 30c of the cam hole 30,
The boss portion 28 (first and second arms 28a, 28b) and the operation shaft 16 (first, second, third arms 16a, 16b, 1)
6c) is operated from the low speed position L to the high speed position H,
The shift member 17 of the transmission 4 meshes with the high speed gear 12,
The second transmission 4 is operated to shift to the high speed position H. Then, as described later, the reverse clutch 22 is transmitted again.

On the contrary, also when the shift lever 26 and the spool 24 are operated from the reverse second speed position R2 to the reverse first speed position R1, the reverse clutch 2 is similarly operated at the neutral position NR.
After the transmission interruption operation of 2 is performed, the roller 28c of the second arm 28b is pushed down by the inclined portion 30d of the cam hole 30, and the boss portion 28 (first and second arms 28a, 28a,
28b) and the operating shaft 16 (first, second, third arm 16)
a, 16b, 16c) is operated from the high speed position H to the low speed position L, and the second transmission 4 is operated to shift to the low speed position L. Then, after this, the reverse clutch 22 is again operated for transmission.

Next, when the speed change lever 26 and the spool 24 are operated to the reverse second speed position R2, the hydraulic oil from the pump 32 is transferred to the third recess 24o of the spool 24 as shown in FIG.
It is supplied to the reverse clutch 22 through the fifth hydraulic oil hole 24p, the accumulator 31 and the fourth hydraulic oil hole 24h, the pressure of the hydraulic oil is smoothly increased by the action of the accumulator 31, and the reverse clutch 22 is again operated for transmission. To be done. In this case, the third drain hole 24k at the neutral position NR shown in FIG. 17 is set to have substantially the same diameter as the first drain hole 24i at the neutral position N shown in FIG. 8, and the hydraulic oil is collected from the accumulator 31 at the neutral position NR. The reverse clutch 22 is configured to be sufficiently discharged so that the reverse clutch 22 is smoothly transmitted when the spool 24 is operated to the reverse second speed position R2.

[Another Embodiment of the Invention] In the configuration of FIG. 1, the second transmission 4 is configured to be capable of shifting in two stages of high and low. It may be configured to be capable of shifting gears.

[0041]

According to the first aspect of the present invention, in the traveling speed change structure for a work vehicle including the first transmission of the hydraulic clutch type and the second transmission of the gear shift type, the first and the first operations can be performed by one manipulator. Multi-gear shifting operations can be performed by the two-gear transmission, and it is no longer necessary to change over the different first and second gear shifting levers to perform a gear shifting operation, and the operability of the work vehicle can be improved. By providing the transmission control valve in the mission case in which the first and second transmissions are installed, the second linkage mechanism for interlockingly coupling the first linkage mechanism (shift control valve) and the shift member is configured to be short and small. Therefore, it is advantageous in terms of simplification of the structure. If the shift member is configured to be mechanically operated based on the operation of the first linkage mechanism (shift control valve), it is possible to easily cope with a mode in which the first transmission of hydraulic clutch type is repeatedly operated over the entire range. Therefore, it is more advantageous in terms of simplification of the structure.

According to a second aspect of the present invention, in the traveling speed change structure for a working vehicle including the hydraulic clutch type first transmission device and the gear shift type second transmission device, one manual operation is performed as in the case of the first aspect. By means of the tool, it becomes possible to perform a multi-stage gear shift operation by the first and second gear shift devices, and it is not necessary to change over the different first and second gear shift levers to perform gear shift operation, thus improving the operability of the work vehicle. I was able to. By providing the transmission case in which the first and second transmissions are installed with the shift control valve, the second operating member and the linkage mechanism for interlockingly connecting the first operating member (shift control valve) and the shift member are short and small. Therefore, it is advantageous in terms of simplification of the structure. If the shift member is configured to be mechanically operated based on the operation of the first operation member (shift control valve), it is possible to easily cope with a mode in which the first transmission of hydraulic clutch type is repeatedly operated over the entire range. Therefore, it is more advantageous in terms of simplification of the structure. A first operation member and a first that are rockably operated
By the second operating member operated along the extending direction of the operating member, even if the operating range of the shift member is relatively large, the second operating member accurately operates the shift member without insufficient operating range. Therefore, it is possible to obtain a highly reliable gear shift operation configuration.

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 the drawings]

FIG. 1 is a schematic front view showing first and second transmissions in a mission case.

FIG. 2 is a hydraulic circuit diagram of a shift control valve, an accumulator, a first forward speed to a reverse clutch, etc. of the first transmission.

FIG. 3 is a front view showing a spool of a shift control valve of the first transmission.

FIG. 4 is a sectional view of a spool of a shift control valve of the first transmission.

FIG. 5 is a side view showing a state where the spool of the shift control valve of the first transmission and the operation gear of the shift lever are linked.

FIG. 6 is a vertical sectional front view showing the vicinity of a shift fork of the second transmission.

FIG. 7 is a cross-sectional view of each part of the spool of the shift control valve of the first transmission.

FIG. 8 is a cross-sectional view of each portion of the spool of the shift control valve of the first transmission at the neutral position.

FIG. 9 is a cross-sectional view of each portion of the spool of the shift control valve of the first transmission at the first forward speed position.

FIG. 10 is a cross-sectional view of each part of the spool of the shift control valve of the first transmission at the forward second speed position.

FIG. 11 is a cross-sectional view of each part of the spool of the shift control valve of the first transmission at the forward third speed position.

FIG. 12 is a cross-sectional view of each part of the spool of the shift control valve of the first transmission at a neutral position between a forward third speed position and a forward fourth speed position.

FIG. 13 is a cross-sectional view of each portion of the spool of the shift control valve of the first transmission at the forward fourth speed position.

FIG. 14 is a cross-sectional view of each portion of the spool of the shift control valve of the first transmission at the fifth forward speed position.

FIG. 15 is a cross-sectional view of each portion of the spool of the shift control valve of the first transmission at the forward sixth speed position.

FIG. 16 is a cross-sectional view of each portion of the spool of the speed change control valve of the first speed change device at the reverse first speed position.

FIG. 17 is a cross-sectional view of each part of the spool of the shift control valve of the first transmission at a neutral position between the reverse first speed position and the reverse second speed position.

FIG. 18 is a cross-sectional view of each portion of the spool of the speed change control valve of the first speed change device at the reverse second speed position.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 mission case 3 1st transmission device 4 2nd transmission device 16, 28, 29 2nd linkage mechanism, linkage mechanism 17 shift member 19, 20, 21 Hydraulic clutch 23 shift control valve 25 1st linkage mechanism, 1st operation member 26 Manual operation tool 28, 28a, 28b Second operation member 30 Cam portion P1 Shaft core

Claims (2)

[Claims] 1. A hydraulic clutch (1) for transmitting a plurality of gears.
9), (20), and (21) are provided in parallel, and the hydraulic clutches (19), (20), and (21) are selectively operated to supply and discharge hydraulic oil, thereby providing a plurality of shifts. A first transmission (3) for performing an operation and a second transmission (4) for performing a plurality of shift operations by operating a shift member (17) are provided, and the first and second transmissions (3), Mission case (1) with (4) in series
The hydraulic clutches (19), (20),
The transmission case (1) is provided with a speed change control valve (23) for performing a speed change operation of the first speed change device (3) by performing a hydraulic oil supply / discharge operation on (21), and is operated manually. The operation tool (26), a first linkage mechanism (25) mechanically interlockingly connecting the manual operation tool (26) and the speed change control valve (23), and the speed change control valve (2).
And a second linkage mechanism (16), (28), (29) for interlockingly coupling the shift member (17) of the second transmission (4) and the first linkage mechanism (25) in the vicinity of 3). Then, the shift control valve (23) is operated via the first linkage mechanism (25) by the operation of the manual operation tool (26),
Moreover, the first and second linkage mechanisms (25), (16),
A traveling speed change structure for a work vehicle, wherein the shift member (17) is operated via (28) and (29). 2. A hydraulic clutch (1) for transmitting a plurality of speed changes.
9), (20), and (21) are provided in parallel, and the hydraulic clutches (19), (20), and (21) are selectively operated to supply and discharge hydraulic oil, thereby providing a plurality of shifts. A first transmission (3) for performing an operation and a second transmission (4) for performing a plurality of shift operations by operating a shift member (17) are provided, and the first and second transmissions (3), Mission case (1) with (4) in series
The hydraulic clutches (19), (20),
The transmission case (1) is provided with a speed change control valve (23) for performing a speed change operation of the first speed change device (3) by performing a hydraulic oil supply / discharge operation on (21), and is operated manually. An operation tool (26) and an operation tool that is rocked around the axis (P1) based on the operation of the manual operation tool (26).
3) a first operating member (25) for operating the first operating member (25), a cam portion (30) provided in the first operating member (25), and the first operating member (25).
Based on the swinging motion of the operating member (25), the cam portion (3
0) to operate the second operating members (28), (28a), (2) operated along the extending direction of the first operating member (25).
8b) and the shift member (1) of the second transmission (4).
7) and the second operating members (28), (28a), (28
b) is provided with interlocking mechanisms (16) and (29), and the shift control valve (23) is operated via the first operation member (25) by the operation of the manual operation tool (26). Is
Moreover, the first and second operation members (25), (28),
(28a), (28b) through the shift member (1
7) A traveling speed change structure for a work vehicle configured to be operated.