JP3163241B2 - Work vehicle traveling speed change structure - 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 speed change structure for a working vehicle.

[0002]

2. Description of the Related Art In a working vehicle such as a combine or the like, as disclosed in, for example, Japanese Patent Application Laid-Open No. Sho 62-177340, a plurality of hydraulic clutches for shifting transmission (see FIGS. 4 and 5 of the above publication). 20a to 20c) are provided in parallel, and a hydraulic clutch type first transmission (the fourth transmission of the above-mentioned publication) that performs a plurality of gear shifting operations by selectively supplying and discharging hydraulic oil to or from the hydraulic clutch. 17 in the figure, and a second gear shift type transmission (16 in FIG. 4 of the above-mentioned publication) that performs a plurality of speed-change operations by operating a shift member.
In some cases, the first and second transmissions are arranged in series in a transmission case. By arranging the first and second transmissions in series in this manner, a multi-stage transmission operation can be performed.

[0003]

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

If the first and second speed change levers are provided as described above, it is necessary to switch the first and second speed change levers at the time of multi-speed shifting operation by the first and second speed change devices. Therefore, there is room for improvement in operability. SUMMARY OF THE INVENTION An object of the present invention is to obtain a simple shift operation configuration with good operability in a traveling speed change structure of a working vehicle including a hydraulic clutch type first transmission and a gear shift type second transmission.

[0005]

[Means for Solving the Problems]

[I] According to the feature of claim 1 or 2, when the shift operation of the first transmission is performed by operating the spool of the shift control valve with the manual operation tool, the linkage mechanism (cam portion) is operated based on the operation of the spool. And a shift member of the second transmission is operated by the shift member. As described above, according to the first or second aspect, the shift operation of the first and second transmissions can be performed by one artificial operation tool.

In this case, since the transmission case in which the first and second transmissions are provided with the transmission control valve, the shift member of the second transmission and the spool of the transmission control valve are close to each other. ing. Accordingly, when the linkage mechanism (the cam portion and the operated member) that operates the shift member of the second transmission based on the operation of the spool of the shift control valve is provided, the linkage mechanism (the cam portion and the activated member) is shortened. Small things can be a good source.

In the case where the above-described first transmission of the hydraulic clutch type and the second transmission of the gear shift type are provided,
The operation of the spool of the transmission control valve in the first transmission can be performed more easily than the operation of the shift member of the second transmission. Thus, for example, at the low speed position of the second transmission, the first transmission is shifted over the entire range, then the second transmission is shifted to the medium speed position, and the first transmission is shifted over the entire range. As a shift operation, a form in which a multi-stage shift state can be obtained by repeatedly performing a shift operation of the hydraulic clutch type first transmission over the entire range is often adopted. Therefore, when the shift member (the second transmission) is mechanically operated based on the operation of the spool of the shift control valve (the first transmission) as in the first or second aspect, A mode in which the first clutch of the hydraulic clutch type is repeatedly shifted over the entire range by performing a measure such as providing a simple accommodating structure to a linkage mechanism (a cam portion and an actuated member) that links the shift member. Can be easily handled.

[II] According to the feature of claim 3, similar to the case of claim 1 or 2, the "action" of the above-mentioned [I] is provided, and in addition to this, the following "action" is provided. It has. When the hydraulic clutch type first transmission and the gear shift type second transmission are provided as described above, the hydraulic clutch type first transmission is repeated over the entire range as described in [I] above. In many cases, a gear shifting operation is employed. Therefore, when the spool of the transmission control valve is operated by the artificial operation tool, the spool (first transmission)
Only the state where only the shift member (second transmission) is operated and the shift member (the second transmission) is not operated, and the state where the spool and the shift member are operated are generated, and the state where the spool and the shift member are operated is more artificial. The operation resistance applied to the operation tool becomes large.

In this case, according to the feature of the third aspect, in a commonly used detent mechanism, the spool and shift by the manual operation tool are less than the resistance of the detent mechanism when only the spool is operated by the manual operation tool. The resistance of the detent mechanism when the member is operated is set small. Thereby, the sum of the operation resistance applied to the artificial operation tool and the resistance of the detent mechanism is set in a state in which only the spool is operated by the artificial operation tool and the shift member is not operated, and a state in which the spool and the shift member are operated. In both cases, they can be set to be substantially the same.

[III] According to the feature of claim 4, as in any one of claims 1 to 3, the "action" described in the above item [I] or [II] is provided, In addition, it has the following “action”. In the case of a first transmission of a hydraulic clutch type, an accumulator is often provided to allow the hydraulic clutch to be smoothly transmitted with less shock. Therefore, when the transmission control valve is configured as a rotary type in which a spool formed in a cylindrical shape is rotated, a space is formed in the spool, so that an accumulator can be provided in the spool.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION

(1) FIG. 1 shows an inside of a transmission 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 via a transmission belt (not shown). The power is transmitted to the input pulley 2 of the transmission case 1 and transmitted to the right and left crawler traveling devices 6 via the second transmission 4 of the gear shift type, the first transmission 3 of the wet hydraulic clutch type, and the side clutch 5. The power branched from the second transmission 4 is transmitted to a reaping unit (not shown) via a gear transmission 7, an output pulley 8, and a reaping 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
A low-speed gear 11 and a medium-speed gear 12 fitted to the transmission shaft 10 so as to be rotatable relative to each other engage with a low-speed gear 14 and a medium-speed gear 15 fixed to the input shaft 9. And the high-speed gear 13 fixed to the transmission shaft 10
The input shaft 9 is engaged with a high-speed gear 16 that is rotatably fitted to the outside of the input shaft 9. A first shift member 17 (corresponding to a shift member) is externally slidably fitted with a spline structure to the transmission shaft 10 between the low-speed gear 11 and the medium-speed gear 12, and a second shift member 18 is fitted to the input shaft 9. (Corresponding to a shift member) is slidably fitted outside with a spline structure.

With the above structure, when the first shift member 17 is engaged with the low-speed gear 11 (low-speed position L), the input shaft 9
Is transmitted from the transmission shaft 10 to the first transmission 3 at a low speed, and the first shift member 17 is
(Medium speed position M), the power of the input shaft 9 is transmitted from the transmission shaft 10 to the first transmission 3 in the medium speed state. When the second shift member 18 is engaged with the high-speed gear 16 (high-speed position H), the power of the input shaft 9 is transmitted from the transmission shaft 10 to the first transmission 3 in a high-speed state.
Can perform three-stage high, middle, and low speed shifting operations.

Next, the first transmission 3 will be described. As shown in FIG. 1, a wet hydraulic multi-plate type forward first speed clutch 19 (corresponding to a hydraulic clutch), a forward second 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. Thereby, forward 1
By selectively supplying hydraulic oil to the speed-reverse clutches 19 to 22 and performing a transmission operation, a shift operation of three forward speeds and one reverse speed can be performed.

(2) Next, the structure of the shift operation of the first transmission 3 will be described. As shown in FIGS.
The transmission case 1 is provided with a rotary type shift 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 forward first speed position F1 to a forward nine speed position F9, a reverse first speed position R1, and a reverse second speed position R2. A piston 24 is provided inside a spool 24 formed in a cylindrical shape. 31a
And accumulator 31 constituted by spring 31b
Is provided.

The spool 24 of the shift control valve 23 has a spool 24 as shown in FIG.
As shown in (4), (8), (B), (C), and (D), the first, second, and third speed clutches 19, 20, and 21 are operated to supply and discharge hydraulic oil. ,
The second and third hydraulic oil holes 24d, 24e, and 24f (see FIG. 8D) supply and discharge hydraulic oil to and from the reverse clutch 22. The fourth and fifth hydraulic oil holes 2 communicate with the accumulator 31.
4g, 24h (see FIG. 8 (c)), accumulator 31
The first, second, third and fourth drain holes 24i for discharging the hydraulic oil of
24j, 24k, 24l (see FIG. 8 (b)), the first recess 24m for discharging the hydraulic oil from the first forward speed to the reverse clutch 19-22 (see FIG. 8 (c), (d)), and the cutting clutch are transmitted. The second recess 24n (see FIG. 8B) that communicates with the operation cylinder 33 (see FIG. 2) that performs the shutoff operation, and the pump 32 (see FIG.
The third concave portion 24o (see FIG. 8) to which the hydraulic oil is supplied from
(See (a)), a sixth hydraulic oil hole 24p (see FIG. 8 (a)) for supplying hydraulic oil from the pump 32 to the accumulator,
The lateral groove 24q connected to the second recess 24n (FIG. 8)
(See (a)). As shown in FIG. 2, the lubricating oil in the transmission case 1 is sucked into the pump 32 through the filter 51 as hydraulic oil, and the hydraulic oil from the pump 32 is supplied to the third recess 2 of the spool 24 of the shift control valve 23.
4o and the sixth hydraulic oil hole 24p or the groove 24q.

As shown in FIGS. 3 and 5, the transmission control valve 2
The gear portion 24 a at the end of the third spool 24 protrudes outside the transmission case 1. A fan-shaped operation gear 25 is swingably supported around a horizontal axis P1 on an upper portion of the transmission case 1, and a speed change lever 26 (corresponding to a manual operation tool) is fixed to the operation gear 25. 25 is engaged with the gear portion 24a of the spool 24.

With the structure described above, the shift lever 26 is
2, the spool 24 is rotated by the operation gear 25, and the spool 24 is moved to the neutral position N and the forward first speed position F1 (the forward first speed clutch 19) shown in FIG.
Transmission operation), forward second speed position F2 (forward second speed clutch 2
0 for transmission operation), third forward speed position F3 (for transmitting third forward speed clutch 21), fourth forward speed position F4 (for transmitting first forward clutch 19), fifth forward speed position F5 (for second forward clutch 20). Transmission operation), forward sixth speed position F6 (transmission operation of third forward speed clutch 21), seventh forward speed position F7 (transmission operation of first forward speed clutch 19), and eighth forward speed position F8 (forward second speed).
9) The forward 9th speed position F9 (the transmission operation of the 3rd forward clutch 21), the 1st reverse speed position R1 (the operation of transmitting the reverse clutch 22), and the 2nd reverse speed position R
By operating the twelfth position 2 (reverse clutch 22 is a transmission operation), the first transmission 3 is repeatedly shifted over the entire range.

(3) Next, the structure of the shift operation of the second transmission 4 will be described. As shown in FIGS. 3 and 6, a first support shaft 27 and a second support shaft 28 are provided in the transmission case 1.
Is fixed, and the first and second shift forks 2 are engaged with the first and second shift members 17 and 18 of the second transmission 4.
9 and 30 (corresponding to an actuated member and a linking mechanism) are slidably fitted to the first and second support shafts 27 and 28, and in the transmission case 1, as shown in FIG. And the input shaft 9 and the transmission shaft 10 are arranged at substantially the same height.

As shown in FIG. 3, a first cam groove 24b (corresponding to a cam portion and a linking mechanism) and a second cam groove 24c (corresponding to a cam portion and a linking mechanism) are formed on the outer surface of the spool 24 of the transmission control valve 23. Are formed, and the first shift fork 29
Operating rod 29a provided with the boss portion of the first cam groove 2
4b, the operating rod 30a provided on the boss of the second shift fork 30 is inserted into the second cam groove 24c.

With the structure described above, the shift lever 26 is moved to the position shown in FIG.
, The spool 24 is rotated by the operation gear 25, and the first transmission 3 is repeatedly shifted over the entire forward range. By the cam grooves 24b and 24c, the first
And the second shift forks 29, 30 are slid along the first and second support shafts 27, 28, and the second transmission 4
Is shifted to a low speed position L, a medium speed position M, and a high speed position H.

As shown in FIG. 3, the first shift fork 2
9 is held in the low-speed position L, the medium-speed position M, and the neutral position N1 by the ball detent mechanism 29b.
9, a ball detent mechanism 30b that holds the second shift fork 30 at the high speed position H and the neutral position N2 is provided on the boss portion of the second shift fork 30. As shown in FIGS. 3 and 4, an opening 24 u is provided in the first and second cam grooves 24 b and 24 c of the spool 24, and the hydraulic oil leaking from the accumulator 31 in the spool 24 passes through the opening 24 u. The first and second cam grooves 24b and 24c are supplied to the first and second cam grooves 24b and 24c through the first and second cam grooves 24b and 24c.
The cam grooves 24b and 24c and the operating rods 29a and 30a of the first and second shift forks 29 and 30 are configured to be lubricated.

(4) As described in the above items (2) and (3),
While the second transmission 4 is shifted to the low-speed position L, the medium-speed position M, and the high-speed position H, the first transmission 3
The transmission operation of the second and third speed clutches 19, 20, and 21 is repeated three times, and the first and second transmissions 3 and 4 can perform nine forward speed shift operations. A shift operation is possible. Next, the shift relationship between the first and second transmissions 3 and 4 will be described.

(4) -1 The state shown in FIG. 9 is a state in which the spool 24 of the shift control valve 23 is operated to the neutral position N (see FIG. 2). To 22 are discharged from the first recess 24m of the spool 24 into the transmission case 1 via 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, and is discharged into the transmission case 1 through the first forward speed to the reverse clutch 1
9 to 22 are operated to cut off the transmission. Hydraulic oil from the pump 32 is supplied to the groove 24q of the spool 24 and the second recess 24.
n to the operation cylinder 33 shown in FIG.
The cutting clutch is operated to cut off the transmission. In the neutral position N, the first and second shift forks 29, 30,
Due to the first and second cam grooves 24b and 24c, the first and second shift members 17 and 18 of the second transmission 4 are in the neutral position N.
1, N2.

When the spool 24 is operated from the neutral position N to the first forward speed position F1 (see FIG. 2), the hydraulic oil from the operation cylinder 33 is discharged to the second position of the spool 24 as shown in FIG.
The mowing clutch is discharged from the recess 24n through the second drain port 35, and the transmission operation of the mowing clutch is performed. At the same time, the operating oil from the pump 32 is
o, the sixth hydraulic oil hole 24p, the accumulator 31 and the first
The hydraulic fluid is supplied to the first-speed forward clutch 19 through the hydraulic oil hole 24d, and the pressure of the hydraulic oil is smoothly increased by the operation of the accumulator 31, so that the first-speed forward clutch 19 is operated for transmission. The spool 24 is moved from the neutral position N to the forward first speed position F1.
, The first and second shift forks 29, 30
The first and second cam grooves 24b and 24c of the spool 24 move with respect to the operation rods 29a and 30a, and the first shift member of the second transmission 4 is moved by the first cam groove 24b as shown in FIG. 17 is operated from the neutral position N1 to the low speed position L.

When the spool 24 is operated from the first forward speed position F1 to the second forward speed position F2 (see FIG. 2), the hydraulic oil of the first forward speed clutch 19 gradually flows through the groove 24r of the spool 24 as shown in FIG. The first-speed forward clutch 19 is operated to cut off the transmission, and the hydraulic oil is supplied to the first hydraulic oil hole 24.
The second forward speed clutch 20 is supplied to the second forward speed clutch 20 via d, and the transmission operation of the second forward speed clutch 20 is rapidly performed without the accumulator 31 functioning. When the spool 24 rotates from the first forward speed position F1 to the second forward speed position F2, the first shift member 17 of the second transmission 4 is maintained at the low-speed position L.

When the spool 24 is operated from the forward second speed position F2 to the forward third speed position F3 (see FIG. 2), the hydraulic oil of the forward second speed clutch 20 gradually flows through the groove 24r of the spool 24 as shown in FIG. Is discharged, the forward second speed clutch 20 is operated to cut off the transmission, and the hydraulic oil is supplied to the first hydraulic oil hole 24.
The driving force is supplied to the third forward speed clutch 21 via d, and the accumulator 31 does not function so that the third forward speed clutch 21 is rapidly transmitted. When the spool 24 rotates from the second forward speed position F2 to the third forward speed position F3, the first shift member 17 of the second transmission 4 is maintained at the low-speed position L.

(4) -2 The spool 24 is moved from the third forward speed position F3 to the fourth forward speed position F4.
2 (see FIG. 2), as shown in FIGS. 2 and 13, at the neutral position NF1 between the third forward speed and the fourth forward speed positions F3 and F4, the hydraulic oil of the third forward speed clutch 21 Is gradually discharged through the groove 24r of
The transmission is cut off by the forward third speed clutch 21 and the spool 2
The hydraulic oil of the accumulator 31 is slightly discharged through the second drain hole 24j and the second drain port 35.

Next, when the spool 24 is operated to the fourth forward speed position F4, the hydraulic oil from the pump 32 is supplied to the third concave portion 24o of the spool 24 and the sixth hydraulic oil hole 24 as shown in FIG.
p, is supplied to the forward first speed clutch 19 via the accumulator 31 and the second hydraulic oil hole 24e, and the pressure of the working oil is smoothly increased by the action of the accumulator 31 to operate the forward first speed clutch 19 for transmission. . In this case, FIG.
2. The second drain hole 24j at the neutral position NF1 shown in FIG.
With the first drain hole 24i at the neutral position N shown in FIG.
It is configured to have a smaller diameter than that in the neutral position NF1 so that a small amount of hydraulic oil is discharged from the accumulator 31. When the spool 24 is operated to the fourth forward speed position F4, the transmission operation of the first forward clutch 19 is performed. Is not too slow. When the spool 24 rotates from the third forward speed position F3 to the fourth forward speed position F4, the first cam member 24b causes the first shift member 17 of the second transmission 4 to shift from the low speed position L to the middle speed position as shown in FIG. M is operated.

When the spool 24 is operated from the fourth forward speed position F4 to the fifth forward speed position F5 (see FIG. 2), the hydraulic oil of the first forward speed clutch 19 gradually flows through the groove 24r of the spool 24 as shown in FIG. Is discharged, the first speed forward clutch 19 is operated to cut off the transmission, and the hydraulic oil is supplied to the second hydraulic oil hole 24.
e, the second forward clutch 20 is supplied to the second forward clutch 20 so that the accumulator 31 does not function and the second forward clutch 20 is rapidly transmitted. When the spool 24 rotates from the fourth forward speed position F4 to the fifth forward speed position F5, the first shift member 17 of the second transmission 4 is maintained at the intermediate speed position M.

When the spool 24 is operated from the fifth forward speed position F5 to the sixth forward speed position F6 (see FIG. 2), the hydraulic oil of the second forward speed clutch 20 gradually passes through the groove 24s of the spool 24 as shown in FIG. Is discharged, the forward second speed clutch 20 is operated to cut off the transmission, and the hydraulic oil is supplied to the second hydraulic oil hole 24.
is supplied to the third forward speed clutch 21 via e, and the third forward speed clutch 21 is rapidly transmitted without the accumulator 31 functioning. When the spool 24 rotates from the fifth forward speed position F5 to the sixth forward speed position F6, the first shift member 17 of the second transmission 4 is maintained at the intermediate speed position M.

(4) -3 The spool 24 is moved from the sixth forward speed position F6 to the seventh forward speed position F7.
2 (see FIG. 2), as shown in FIGS. 2 and 17, at a neutral position NF2 between the sixth forward speed and the seventh forward speed positions F6 and F7, the operating oil of the third forward speed clutch 21 Is gradually discharged through the groove 24r of
The transmission is cut off by the forward third speed clutch 21 and the spool 2
The working oil of the accumulator 31 is slightly discharged through the fourth drain hole 24k and the second drain port 35 of the fourth.

Next, when the spool 24 is operated to the seventh forward speed position F7, the hydraulic oil from the pump 32 is supplied to the third concave portion 24o of the spool 24 and the sixth hydraulic oil hole 24 as shown in FIG.
p, is supplied to the forward first speed clutch 19 via the accumulator 31 and the third hydraulic oil hole 24f, and the pressure of the working oil smoothly rises by the action of the accumulator 31 to operate the forward first speed clutch 19 for transmission. . In this case, FIG.
The third drain hole 24k at the neutral position NF2 shown in FIG.
With the first drain hole 24i at the neutral position N shown in FIG.
The diameter is set smaller than that of the first position, and the hydraulic oil is discharged only slightly from the accumulator 31 at the neutral position NF2. When the spool 24 is operated to the forward seventh speed position F7, the transmission operation of the forward first speed clutch 19 is performed. Is not too slow. When the spool 24 rotates from the sixth forward speed position F6 to the seventh forward speed position F7, the first shift member 17 of the second transmission 4 is moved from the middle speed position M to the neutral position by the first cam groove 24b as shown in FIG. The operation is changed to N1, and the second shift member 18 is operated from the neutral position N2 to the high-speed position H by the second cam groove 24c.

When the spool 24 is operated from the seventh forward speed position F7 to the eighth forward speed position F8 (see FIG. 2), the hydraulic oil of the first forward speed clutch 19 gradually flows through the groove 24r of the spool 24 as shown in FIG. Is discharged, the first speed forward clutch 19 is operated to cut off the transmission, and the hydraulic oil is supplied to the third hydraulic oil hole 24.
The second forward speed clutch 20 is supplied to the second forward speed clutch 20 via f, and the transmission operation of the second forward speed clutch 20 is rapidly performed without the accumulator 31 functioning. When the spool 24 rotates from the seventh forward speed position F7 to the eighth forward speed position F8, the state where the second shift member 18 of the second transmission 4 is operated to the high speed position H is maintained.

When the spool 24 is operated from the eighth forward speed position F8 to the ninth forward speed position F9 (see FIG. 2), the hydraulic oil of the second forward speed clutch 20 gradually flows through the groove 24r of the spool 24 as shown in FIG. Is discharged, the forward second speed clutch 20 is operated to cut off the transmission, and the hydraulic oil is supplied to the third hydraulic oil hole 24.
The driving force is supplied to the third forward speed clutch 21 via f, and the third forward speed clutch 21 is rapidly transmitted without the accumulator 31 functioning. When the spool 24 rotates from the eighth forward speed position F8 to the ninth forward speed position F9, the second shift member 18 of the second transmission 4 is maintained at the high-speed position H.

(4) -4 The spool 24 is moved from the neutral position N to the reverse first speed position R1 (FIG. 2).
21), the operating oil from the operation cylinder 33 is discharged from the second concave portion 24n of the spool 24 via the second drain port 35 as shown in FIG. 21, and the mowing clutch is transmitted. At the same time, the hydraulic oil from the pump 32 is supplied to the third recess 24o of the spool 24, the sixth hydraulic oil hole 24p, the accumulator 31, and the fourth hydraulic oil hole 24g.
, And is supplied to the reverse clutch 22, and the pressure of the hydraulic oil smoothly rises by the operation of the accumulator 31,
The reverse clutch 22 is operated for transmission. When the spool 24 rotates from the neutral position N to the reverse first speed position R1, the operating rods 29a, 3 of the first and second shift forks 29, 30 are rotated.
0a, the first and second cam grooves 24 of the spool 24
b and 24c move, and as shown in FIG.
By c, the first shift member 17 of the second transmission 4 is operated from the neutral position N1 to the middle speed position M.

When the spool 24 is operated from the first reverse speed position R1 to the second reverse speed position R2 (see FIG. 2), FIGS.
As shown in FIG. 2, before the neutral position NR between the first reverse speed and the second reverse speed position R1 and R2, the hydraulic oil of the reverse clutch 22 is discharged via the first recess 24m of the spool 24 and the first drain port. Then, the reverse clutch 22 is operated to cut off the transmission, and at the neutral position NR, through the fourth drain hole 24l and the second drain port 35 of the spool 24,
The operating oil of the accumulator 31 is discharged.

Next, when the spool 24 is operated to the reverse second speed position R2, the hydraulic oil from the pump 32 is supplied to the third concave portion 24o of the spool 24 and the sixth hydraulic oil hole 24 as shown in FIG.
p, is supplied to the reverse clutch 22 through the accumulator 31 and the fifth hydraulic oil hole 24h, and is supplied to the accumulator 31.
, The pressure of the hydraulic oil rises smoothly, and the reverse clutch 22 is transmitted again. In this case, the fourth drain hole 24l at the neutral position NR shown in FIG.
The diameter of the first drain hole 24i at the neutral position N shown in FIG.
1 is configured so that hydraulic oil is sufficiently discharged.
When the spool 24 is operated to the second reverse speed position R2, the reverse clutch 22 is smoothly transmitted.
The spool 24 moves from the reverse first speed position R1 to the reverse second speed position R2.
3, the first shift member 17 of the second transmission 4 is moved to the middle speed position M by the first cam groove 24b, as shown in FIG.
To the neutral position N1, and the second shift member 18 is operated from the neutral position N2 to the high-speed position H by the second cam groove 24c.

(5) As shown in FIGS. 3 and 7, a cam plate 36 is provided at the end of the spool 24 of the speed change control valve 23 opposite to the gear portion 24a. N, forward first speed to forward nine speed positions F1 to F
9, concave portions are formed in portions corresponding to the first reverse speed and the second reverse speed positions R1 and R2. A ball detent mechanism 37 (corresponding to a detent mechanism) is provided for the cam plate 36, and the spool 24 is in the neutral position N, the first forward speed to the ninth forward speed positions F1 to F9, the first reverse speed and the second reverse speed R1. , R2
It is constituted so that it may be held.

As described in (4) -1 to (4) above, between the third forward speed position F3 and the fourth forward speed position F4, between the sixth forward speed position F6 and the seventh forward speed position F7, and at the neutral position N Between the first and second reverse speed positions R1 and between the first reverse speed position R1 and the second reverse speed position R2, the shift lever 26 operates the spool 24 at the same time as the first or second shift member 17,1.
Operation 8 is performed. Therefore, at this time, the spool 24
Therefore, the operation resistance applied to the shift lever 26 becomes large. Conversely, between the forward 1, 2 and 3 speed positions F1, F2 and F3, between the forward 4 and 5 and 6 speed positions F4, F5 and F6, and at the forward 7, 8 and 9 speed positions F7, F8 and F9. In each of the above, only the operation of the spool 24 is performed by the shift lever 26, and the operation of the first and second shift members 17, 18 is not performed. Therefore, at this time, the operation resistance applied from the spool 24 to the shift lever 26 is small.

In this case, as shown in FIG. 7, an inclined surface 36a between the third forward speed position F3 and the fourth forward speed position F4, the sixth forward speed position F6, and the seventh forward speed are formed in the concave portions adjacent to the cam plate 36, as shown in FIG. The inclined surface 36a between the position F7, the inclined surface 36a between the neutral position N and the first reverse speed position R1, and the inclined surface 36a between the first reverse speed position R1 and the second reverse speed position R2 are different from each other. It is set to be gentler than the inclined surfaces of the concave portions such as the forward first, second, and third speed positions F1, F2, and F3. Thereby, between the third forward speed position F3 and the fourth forward speed position F4, the sixth forward speed position F6
And the seventh forward speed position F7, between the neutral position N and the first reverse speed position R1, and between the first reverse speed position R1 and the second reverse speed position R2.
Between the ball detent mechanism 37 and the shift lever 26, the resistance is small. Conversely, between the forward 1, 2 and 3rd speed positions F1, F2, F3, forward 4,
Between the fifth and sixth speed positions F4, F5, F6 and forwards 7, 8,
Between each of the ninth speed positions F7, F8, and F9, the resistance applied to the shift lever 26 from the ball detent mechanism 37 becomes large.

With the above structure, between the third forward speed position F3 and the fourth forward speed position F4, between the sixth forward speed position F6 and the seventh forward speed position F7, and between the neutral position N and the first reverse speed position R1. And the resistance applied to the shift lever 26 between the first reverse speed position R1 and the second reverse speed position R2 (the sum of the operating resistance of the spool 24 and the resistance of the ball detent mechanism 37); Between the speed positions F1, F2, F3,
Resistance applied to the speed change lever 26 between each of the forward 4, 5 and 6 speed positions F4, F5 and F6 and between each of the forward 7, 8 and 9 speed positions F7, F8 and F9 (the operation resistance of the spool 24 and the ball detent mechanism) 37), both resistances applied to the shift lever 26 are set to be substantially the same.

(6) As shown in FIG.
And the input shaft 9 are disposed at substantially the same height, and the transmission control valve 23 is disposed above the transmission shaft 10. The first and second drain ports 34 and 35 of the transmission control valve 23 are connected to the input shaft 9. 9 and the transmission shaft 10 side. Transmission lever 26
Shifts the shift control valve 23 (spool 24) to the neutral position N, NF1, NF2, NR, forward first speed to forward nine speed position F
1 to F9, every time the reverse 1 speed and reverse 2 speed positions R1 and R2 are operated, the first and second drain ports 3
When the hydraulic oil is discharged from the transmission shafts 4 and 35, the hydraulic oil is applied to the input shaft 9 and the transmission shaft 10 and returned into the transmission case 1.

As described above, the hydraulic oil discharged from the first and second drain ports 34 and 35 of the shift control valve 23 causes the second shift member 18, the low-speed gear 14, the medium-speed gear 15, and the The lubrication of the high-speed gear 16 and the like is performed, and the first shift member 17 of the transmission shaft 10, the low-speed gear 11,
Lubrication of the medium-speed gear 12, the high-speed gear 13, and the like is performed. Therefore, the level A of the hydraulic oil (lubricating oil) stored in the transmission case 1 is set slightly below the transmission shaft 10 as shown in FIG.

[Another Embodiment of the Invention] In the configuration shown in FIG. 1, the second transmission 4 is configured to be able to perform a shift operation in three stages of high, medium and low. The second transmission 4 is shown in FIG. As shown in the figure, a four-speed shift operation may be performed. As shown in FIG. 24, a transmission shaft 38 is arranged concentrically with respect to the input shaft 9 to which the input pulley 2 is fixed so as to be rotatable relative to the input shaft 9, and transmission shafts 39 and 40 are arranged with respect to the transmission shaft 38. I have.
A low-speed gear 41 and a high-speed gear 42 which are rotatably fitted on the transmission shaft 38 are connected to the low-speed gear 4 fixed to the transmission shaft 39.
3 and a high-speed gear 44, and a low-speed gear 45 and a high-speed gear 46 fixed to the transmission shaft 38 are rotatably fitted to the transmission shaft 40.
8 is occluded. A shift member 49 is externally slidably fitted to the transmission shaft 38 between the low-speed gear 41 and the high-speed gear 42 in a spline structure. Are externally slidably fitted with a spline structure.

With the above structure, the power is transmitted from the input shaft 9 to the transmission shaft 39, and the shift member 49 is operated to mesh with the low-speed gear 41 or the high-speed gear 42, so that the power of the transmission shaft 39 can be increased and lowered in two stages. The transmission is transmitted to the transmission shaft 38 through a speed change operation. When the shift member 50 is operated to mesh with the low-speed gear 47 or the high-speed gear 48, the power of the transmission shaft 38 is speed-changed in two stages of high and low, and the transmission shaft is operated. It is transmitted to 40. As described above, in the second transmission 4, the power is shifted to four speeds and transmitted to the first transmission 3.

[0047]

According to the first or second aspect of the present invention, in a traveling speed change structure of a working vehicle provided with a first transmission of a hydraulic clutch type and a second transmission of a gear shift type, the first manual operation device is used to perform the first operation. And the multi-speed transmission by the second transmission can be performed, so that it is not necessary to change the first and second transmission levers to perform the transmission operation,
The operability of the work vehicle was improved. By providing a shift control valve in a transmission case in which the first and second transmissions are provided, a linkage mechanism (a cam portion and an actuated member) that operates a spool and a shift member of the shift control valve is configured to be short and small. This is advantageous in terms of simplification of the structure. Further, if the shift member is mechanically operated based on the operation of the spool of the shift control valve, it is possible to easily cope with a mode in which the first clutch of the hydraulic clutch type is repeatedly shifted over the entire range. This is further advantageous in terms of simplification of the structure.

According to the features of claim 3, claim 1 or 2
"Effects of the Invention" of Claim 1 or 2 as in the case of
It has. According to the feature of the third aspect, in the case where the first clutch of the hydraulic clutch type is repeatedly shifted over the entire range, the resistance applied to the manual operation tool (the operating resistance from the spool and the shift member and the detent mechanism). Can be made substantially the same at any shift position, so that it is possible to eliminate a sense of incongruity that the resistance applied to the artificial operation tool varies depending on the shift position, and to improve operability. Improvement was able to be aimed at.

According to the feature of the fourth aspect, similarly to the case of any one of the first to third aspects, there is provided the “effect of the invention” of one of the first to third aspects. According to the feature of claim 4, in the case where the accumulator for the hydraulic clutch of the first transmission is provided, by installing the accumulator on the spool of the transmission control valve, it is possible to omit a special arrangement space for the accumulator. This is advantageous in terms of overall miniaturization.

Incidentally, reference numerals are written 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 front view showing first and second transmissions in a transmission case.

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

FIG. 3 is a front view showing a spool of a shift control valve of the first transmission, and first and second shift forks of the second 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 linked state of a spool of a shift control valve of the first transmission and an operation gear of a shift lever.

FIG. 6 is a longitudinal sectional side view showing a spool of a shift control valve of the first transmission, and first and second shift forks of the second transmission.

FIG. 7 is a side view showing a cam plate and a ball detent mechanism in a spool of a shift control valve of the first transmission.

FIG. 8 is a sectional view of each part of a spool of a shift control valve of the first transmission.

FIG. 9 is a sectional view of each part of the spool of the shift control valve of the first transmission at the neutral position.

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

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

FIG. 12 is a sectional view of each part of the spool of the shift control valve of the first transmission at the third forward speed position;

FIG. 13 is a sectional view of each part of the spool of the shift control valve of the first transmission at a neutral position between the third forward speed position and the fourth forward speed position;

FIG. 14 is a sectional view of each part of the spool of the shift control valve of the first transmission at the fourth forward speed position.

FIG. 15 is a sectional view of each part of the spool of the shift control valve of the first transmission at the fifth forward speed position.

FIG. 16 is a sectional view of each part of the spool of the shift control valve of the first transmission at the sixth forward speed position.

FIG. 17 is a sectional view of each part of the spool of the shift control valve of the first transmission at a neutral position between the sixth forward speed position and the seventh forward speed position;

FIG. 18 is a sectional view of each part of the spool of the shift control valve of the first transmission at the seventh forward speed position;

FIG. 19 is a sectional view of each part of the spool of the transmission control valve of the first transmission at the eighth forward speed position.

FIG. 20 is a sectional view of each part of the spool of the shift control valve of the first transmission at the ninth forward speed position;

FIG. 21 is a sectional view of each part of the spool of the shift control valve of the first transmission at the reverse first speed position.

FIG. 22 is a sectional view of each part of the spool of the shift control valve of the first transmission at a neutral position between the first reverse speed position and the second reverse speed position;

FIG. 23 is a sectional view of each part of the spool of the shift control valve of the first transmission at the second reverse speed position.

FIG. 24 is a schematic front view showing first and second transmissions in a transmission case according to another embodiment of the invention;

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 transmission case 3 first transmission 4 second transmission 17, 18 shift member 19, 20, 21 hydraulic clutch 23 shift control valve 24 spool of shift control valve 24 b, 24 c linkage mechanism, cam portion 26 artificial operation tool 29, 30 Linkage mechanism, actuated member 31 Accumulator 37 Detent mechanism

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-62-177340 (JP, A) Japanese Utility Model 1983-114958 (JP, U) Japanese Utility Model Application 1984-137446 (JP, U) Field (Int.Cl. ⁷ , DB name) F16H 61/26-61/36 F16H 63/00-63/38

Claims (4)

(57) [Claims] A hydraulic clutch for transmitting a plurality of transmissions (1).
9), (20), and (21) are provided in parallel, and the hydraulic oil clutches (19), (20), and (21) are selectively operated to supply and discharge hydraulic oil, so that a plurality of gear shifting operations are performed. And a second transmission (4) that performs a plurality of speed-change operations by operating shift members (17) and (18).
And the second transmissions (3) and (4) are arranged in series in the transmission case (1), and the hydraulic clutches (19), (20) and (21) are operated to supply and discharge hydraulic oil. A transmission control valve (23) for performing a shift operation of the first transmission (3) is provided in the transmission case (1), and a spool (24) of the transmission control valve (23) can be artificially operated. An operating tool (26), and a shift member (17) of the second transmission (4).
8) is mechanically linked with a spool (24) of the shift control valve (23) to operate the shift members (17) and (18) based on the operation of the spool (24). 24b), (24c), (29), and (30), the spool (24) of the shift control valve (23) is operated by the operation of the artificial operation tool (26), and the first transmission device is operated. (3) The gearshift operation is performed, and the link mechanism (24) is operated.
b), (24c), (29), and (30) are operated such that the shift members (17) and (18) are operated to shift the second transmission (4). The traveling speed change structure of a working vehicle. 2. The spool (2) of the shift control valve (23).
Cam portions (24b) and (24c) formed on the outer surface of 4)
And the actuated members (29) and (30) operated by the cam portions (24b) and (24c) based on the operations of the spools (17) and (18), the linking mechanism (24b), The traveling speed change structure for a working vehicle according to claim 1, wherein (24c), (29), and (30) are configured. 3. The spool (2) of the shift control valve (23).
4) is provided at each shift position, and the resistance of the detent mechanism (37) when only the spool (24) is operated by the manual operation tool (26) is provided. The spool (24) and the shift member (17) are moved by the manual operation tool (26).
The traveling speed change structure for a working vehicle according to claim 1 or 2, wherein a resistance of the detent mechanism (37) when the (18) is operated is set to be small. 4. The transmission control valve (23) is of a rotary type for rotating the spool (24) formed in a cylindrical shape, and a hydraulic clutch (19) of the first transmission (3). The traveling speed change structure for a working vehicle according to any one of claims 1 to 3, wherein accumulators (31) for the, (20), and (21) are provided in the spool (24).