JPH0663565B2 - Transmission structure for traveling of work vehicle - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention is provided with a shift gear type transmission capable of four-stage switching, a hydraulic cylinder for switching the shift gears, and a shift valve switching operation. The present invention relates to a traveling power transmission structure of a work vehicle configured to perform.

[Conventional technology]

Conventionally, the work vehicle has been disclosed in, for example, JP-A-62-52251. That is, a pair of hydraulic cylinders that are provided with two shift parts that are shifted in two stages by switching one shift gear in a parallel state, and that individually switch the two shift gears, and one shift valve that controls these hydraulic cylinders. , And a hydraulic piston for operating the shift clutch is provided, and the control valve of the hydraulic piston and the hydraulic cylinder are linked so that the shift clutch automatically engages and disengages in association with switching of any of the two shift parts. Equipped with a clutch control mechanism
When the shift valves are switched, the shift parts are switched by hydraulic cylinders so that the speed of each shift part reaches a predetermined speed state, and the shift clutch is disengaged to shift gears and after shifting is completed. The operation of engaging the shift clutch is automatically performed by the hydraulic piston.

[Problems to be solved by the invention]

In the case of the conventional structure, since the two speed change parts are arranged in parallel, any of the predetermined reduction ratios that need to be expressed in each of the four speed change stages can be achieved at only one speed change part at a single location. It was necessary to make it appear, and it was necessary to make each of the speed change parts relatively large so as to expose a large reduction ratio.

SUMMARY OF THE INVENTION An object of the present invention is to provide a gear shifter that can be easily operated while allowing a shifter unit to be downsized and smoothly shifting a shift gear.

[Means for solving problems]

In the transmission structure for traveling of the work vehicle according to the present invention, two of the synchromesh type two-stage switchable transmission parts are arranged in a state of being interlocked in series, and any of the transmission parts is on the transmission better side. Alternatively, a transmission clutch is arranged on the lower transmission side, and a pair of hydraulic cylinders for switching and operating the shift gear of the one transmission portion and the shift gear of the other transmission portion separately; a hydraulic piston for operating the transmission clutch; One shift valve for controlling each of the hydraulic cylinders is provided, and the shift clutch is automatically disengaged in cooperation with the disengagement operation of any one of the shift gears, and the actuation operation of any of the shift gears. In a state in which the shift clutch is automatically engaged in cooperation with the control valve of the hydraulic piston, A linked clutch control mechanism is provided, and the shift portion closer to the shift clutch is disengaged in association with the disengagement operation of the shift portion farther from the shift clutch of the shift portion, and A linkage mechanism is provided in which one hydraulic cylinder and the other hydraulic cylinder are linked to each other in a state in which the distant one of the transmission parts is linked to the entry operation and the nearer one of the transmission parts is automatically turned on. This is a characteristic configuration. The action and effect are as follows.

[Action]

As the speed change valve is changed, each hydraulic cylinder changes the shift gear to change the speed change part to a predetermined speed state, and the hydraulic piston is automatically operated by the clutch control mechanism to open and close the speed change clutch. Manipulate.

Rotational power is introduced into one of the two-speed transmission units to adjust the speed, which is further transmitted from the transmission unit to the other two-speed transmission unit to be output after the speed is adjusted, whereby the four-speed speed is realized. It That is, the speed is adjusted at two locations, one gear shifting portion and the other gear shifting portion. Therefore, even if the speed reduction ratio of each transmission unit is set to be smaller than the conventional one, the overall speed reduction ratio can be set to a desired value.

When switching the transmission part farther from the shift clutch, the transmission part closer to the shift clutch is temporarily turned off by the linkage mechanism so that the transmission structure is located between the remote transmission part and the shift clutch. The rotation inertia of the member is suppressed from being transmitted to the transmission unit, and the shift gear and the gear to be engaged easily rotate in synchronization.

〔The invention's effect〕

Shifting can be easily done by simply switching the shift valve, but by connecting both shifting parts in series, it is possible to create both shifting parts in a small size with a relatively small reduction ratio, making the overall mission compact. Became possible.

Moreover, it is possible to switch the shift portion farther from the shift clutch while facilitating the synchronization of the shift gear by the action of the linkage mechanism, and to shift smoothly.
Moreover, it is possible to be quiet because gear noise is less likely to occur.

〔Example〕

 Next, examples will be shown.

As shown in FIG. 1 and FIG. 2, the rotation output of the engine (E) is introduced into the transmission case (2) through the main clutch (C ₁ ) and the input cylinder shaft (1), and a synchromesh type main shaft is introduced. The rotation output of the main transmission device (3) is transmitted to the transmission device (3), and the rotation output of the main transmission device (3) is transferred via the synchromesh type forward / reverse switching device (4) and the shifting clutch (C ₂ ). The transmission (5) is configured to be transmitted to the device (5), and the output shaft (6) of the auxiliary transmission (5) is directly connected to the rear wheel differential mechanism (7) and is also transmitted via the gear transmission mechanism (8). A transmission structure for traveling of an agricultural tractor is configured in conjunction with the front wheel transmission shaft (9).

The main transmission (3) has a first main transmission section (3a) and a second shift gear (12) that can be switched between two stages by a first shift gear (11).
The second main transmission unit (3b) capable of changing gears and the first main transmission unit (3a)
Is connected in series so that the rotation output of the first main transmission unit (3b) is transmitted to the second main transmission unit (3b). By combining with the speed stage that appears in (4), it is possible to change gears in four stages. The auxiliary transmission device (5) includes a first auxiliary transmission unit (5a) capable of switching between two stages by the third shift gear (13) and a second auxiliary transmission unit (5b) capable of switching between two stages by the fourth shift gear (14). The first sub-transmission unit
The rotational output of (5a) is connected in series so as to be transmitted to the second subtransmission unit (5b), and the speed stage and the second subtransmission that the first subtransmission unit (5a) appears. By combining with the speed stages that appear in the part (5b), it is possible to change gears in four stages. That is, as a whole, it is possible to change the speed in 16 steps by combining the four speeds by the main transmission (3) and the four speeds by the auxiliary transmission (5) on the forward side and the reverse side respectively. . The operating structure for this speed is constructed as follows.

That is, as shown in FIG. 4, a first hydraulic cylinder in which a first link type interlocking mechanism (15) is interlocked with a sliding first shifter (11a) for slidingly operating a first shift gear (11). (16),
A second hydraulic cylinder (18) and a third shift gear (13) in which a second link type interlocking mechanism (17) is interlocked with a sliding second shifter (12a) for slidingly operating the second shift gear (12). ) Sliding operation of the third hydraulic cylinder (20) and the fourth shift gear (14) that are interlocked by the third link type interlocking mechanism (19) with the third sliding type shifter (13a) Sliding fourth shifter (14
Each of the fourth hydraulic cylinders (22) interlocked with the fourth link type interlocking mechanism (21) to a) is connected to the upper part of the mission case (2) as shown in FIG. Oil passage forming member
It is attached to the bottom side of (23). That is, the first shift gear
(11) is the first hydraulic cylinder (16) via the first link type interlocking mechanism (15), and the second shift gear (12) is the second hydraulic cylinder (18) via the second link type interlocking mechanism (17). ), The third
The shift gear (13) is a third hydraulic cylinder (20) via a third link type interlocking mechanism (19), and the fourth shift gear (14) is a fourth
Switching operations are performed by the fourth hydraulic cylinder (22) via the link type interlocking mechanism (21). Then, the oil passage forming member (23) is provided with connecting oil passages (l ₂ ) to (l ₈ ) formed as shown in FIG. 5 to form the first to fourth hydraulic cylinders (16), (18). ), (20), (22), one rotary type speed change valve (24) connected as shown in FIG. 3 is attached to the upper surface side of the oil passage forming member (23), and the speed change valve (24) is set to 1 It has one neutral operating position (N) and 16 transmission operating positions (I) to (XVI),
By being operated to these operating positions (N), (I) or (XVI), the transmission cut-off state or speed-expressing transmission corresponding to the operating position (N) or (I) or ... (XVI) is transmitted. First to fourth so that the main transmission (3) and the auxiliary transmission (5) are in the state
The hydraulic cylinders (16), (18), (20) and (22) are configured to be controlled.

As shown in FIGS. 3 and 7, the second hydraulic cylinder (18)
And for each of the third hydraulic cylinder (20), a pair of hydraulic pistons (25a), (25b) or (26a), (26b) for operating this hydraulic cylinder (18) or (20) in a neutral state. The hydraulic pistons (25a), (25b) or (26a) (2
6b) control valve (27) or (28) is connected to the hydraulic cylinder (16) or (22), and the control valve (27) or (28) slide spool (27a) or (28a) The working stroke is the piston of the hydraulic cylinder (16) or (22)
Use the interlocking mechanism (29) or (30) equipped with interlocking flexibility to reduce the operating stroke of (16a) or (22a) and move the control valve (27) or (28) to the hydraulic cylinder ( 1
6) or (22) in conjunction with, the main transmission side linkage mechanism (3) that links the first hydraulic cylinder (16) and the second hydraulic cylinder (18).
1) Or 3rd hydraulic cylinder (20) and 4th hydraulic cylinder (22)
And a sub-transmission side link mechanism (32) that links the and.
The linkage mechanism (31) or (32) is provided in the main transmission device (3) or the auxiliary transmission device (5) at the first main transmission portion (3a) or the second auxiliary transmission portion farther from the speed change clutch (C ₂ ). When switching the portion (5b), the second main transmission portion (3) closer to the shifting clutch (C ₂ )
b) or the first subtransmission unit (5a) is operated to temporarily switch to the neutral position. That is, the hydraulic cylinder (1
As (6) or (22) cuts from the transmission position before shifting toward the new transmission position, the interlocking mechanism (29) or (30)
One transmission part (29a) or (29b) or (30a) or
(30b) separates from the passive part (29c) or (30c), and the control valve (27) or (28) switches from one oil discharge position (a) to the oil supply position (b) due to self-restoring force, A pair of hydraulic pistons (25a), (25b) or (26a), (26b) are driven to the approach side by the hydraulic pressure from the control valve (27) or (28),
One of the hydraulic pistons (25a), (25b) or (26a) due to the difference in pressure receiving area between these hydraulic pistons (25a), (25b) or (26a), (26b) and the pistons (18a) or (20a). Alternatively, (26b) pushes back the hydraulic cylinder (18) or (20) to the neutral state in preference to the pressure oil from the transmission valve (24). Then, as the hydraulic cylinder (16) or (22) reaches a new transmission position, the other transmission portion (29b) or (29a) or (30b) or (30a) of the interlocking mechanism (29) or (30) Contacts the passive section (29c) or (30c) and the control valve (2
7) or (28) is switched from the oil supply position (b) to the other oil discharge position (a), and the pressure oil from the transmission valve (24) pushes the hydraulic cylinder (18) or (20) to the neutral position. Operating hydraulic piston (25a) or (25b) or (26a) or (26b)
Is pushed back to the standby position and the hydraulic cylinder (18) or (20) is returned to the original transmission state.

The swinging arm (34) is attached to the sliding type shifter (33a) that slides the switching gear (33) of the forward / reverse switching device (4).
Forward / backward lever (36) for manual operation via the rotary support shaft (35) of (34)
Are linked.

Together configured to operate by a hydraulic piston (37) that the shifting clutch (C ₂₎ and furnished to the clutch body as shown in FIG. 1, the shift clutch (C ₂₎ is gradually given incoming pressurized state Modulation valve (38) for gradually increasing the pressure of the hydraulic piston (37) and the clutch for shifting
A control valve (39) for controlling the hydraulic piston (37) for turning on and off (C ₂ ) is attached to the upper surface side of the oil passage forming member (23). And the control valve
A sequence valve (41) connected to a pilot oil passage (40) having an oil passage forming member (23) formed in the pilot operation portion of (39) and connected to a third hydraulic cylinder (20), The sliding spool (41a) of the sequence valve (41) is linked to the piston (20a) of the third hydraulic cylinder (20). Connected to the operation oil chamber of the pistons (25a), (25b) by an automatic oil passage switching valve (43) so as to be switched and connected to the control valve (27), and on the upper surface side of the oil passage forming member (23). The installed sequence valve (44), the link type interlocking mechanism (45) that interlocks the sliding spool of this sequence valve (44) with the forward / reverse lever (36), the control valve (39) and the hydraulic pump (P). The sequence valve (47), which is installed in the connecting oil passage (46) and is connected to the second hydraulic cylinder (18), Bed sliding spool (47) (47a) a second hydraulic cylinder
The interlocking mechanism (2) interlocked with the piston (18a) of (18)
The first to fourth hydraulic cylinders (16) and (16) and (16) are provided by the flexible interlocking mechanism (48) similar to 9), the main speed change side linkage mechanism (31) and the sub speed change side linkage mechanism (32). 18), (20), (2
2) and the forward / reverse switching device (4) and the control valve (39) are linked to form a clutch control mechanism (49). The clutch control mechanism (49) cooperates with the switching of the first to fourth shift gears (11), (12), (13), (14) and the switching gear (33) so that the shift clutch (C ₂ ) is automatically operated. It operates so as to turn on and off. That is, when the second main transmission unit (3b) is switched, as the piston (18a) of the second hydraulic cylinder (18) is turned off from the transmission position before the shift toward the new transmission position, the interlocking mechanism (48 ) One transmission part
(48a) or (48b) separates from the passive part (48c) and the sequence valve (47) switches from one refueling position (b) to the oil draining position (a) due to self-restoring force, and the hydraulic piston (37) The hydraulic piston (37) is depressurized to the clutch disengaged state by draining oil from the operation chamber of (1). Then, as the piston (18a) enters a new transmission position and operates, the other transmission portion (48b) or (48a) of the interlocking mechanism (48) contacts the passive portion (48c) and the sequence valve (47). ) Is returned to the oil supply position (b) and oil is supplied to the operation chamber of the hydraulic piston (37) to pressurize the hydraulic piston (37) into a clutched state. And the first
When switching the main transmission (3a), the main transmission side linkage mechanism (3
For 1), the second hydraulic cylinder (18) is operated as described above, and the sequence valve (47) is switched in the same manner as when switching the second main transmission unit (3b), so that the first hydraulic cylinder (16) )
The hydraulic piston (37) is decompressed as the piston (16a) of the first gear shifts from the transmission position before gear shifting toward the new transmission position, and the piston (16a) enters the new transmission position and operates. (37) returns to the pressurized state.
When switching the first sub transmission unit (5a), the third hydraulic cylinder (2
As the piston (20a) of (0) cuts and operates from the transmission position before gear shifting toward the new transmission position, one transmission part (42a) or (42b) of the interlocking mechanism (42) becomes the passive part (42c). Away from the sequence valve (41) switches from one refueling position (b) to the oil draining position (a) due to the self-restoring force, and the control valve (39) becomes the clutch disengaged position due to the self-restoring force. Of. Then, as the piston (20a) enters a new transmission position and operates, the other transmission portion (42b) of the interlocking mechanism (42).
Or (42a) contacts the passive part (42c) and the sequence valve
The (41) is switched to the other refueling position (b), and the control valve (39) is returned to the clutch engaged position by the pilot pressure oil. Then, at the time of switching the second subtransmission unit (5b), the third hydraulic cylinder (20) is operated as described above for the subtransmission side interlocking mechanism (32) and the first subtransmission unit (5a) is operated.
The sequence valve (41) is switched in the same manner as when the control valve is switched, so that the piston (22a) of the fourth hydraulic cylinder (22) is turned off from the transmission position before the gear shift toward the new transmission position and the control valve is operated. The control valve (39) returns to the clutch engaged position as (39) becomes the clutch disengaged position and the piston (22a) enters a new transmission position and operates. When the forward / reverse switching device (4) is switched, the interlocking mechanism moves as the forward / reverse lever (36) swings.
(45) One transmission part (45a) or (45b) is separated from the passive part (45c), and the sequence valve (44) is self-restoring force from one oil discharge position (a) to the oil supply position (b). The hydraulic piston (25a) or (25b) pushes the piston (18a) to the neutral position and operates the sequence valve (47) via the interlocking mechanism (48).
The hydraulic piston (37) is depressurized by operating the one oil supply position (b) to the oil discharge position (a). Then, as the forward / reverse lever (36) moves to the forward or reverse position, the other transmission portion (45b) or (45a) of the interlocking mechanism (45) is moved.
Comes into contact with the passive part (45c), the sequence valve (44) is switched to the other oil drain position (a), and the piston (18a) moves to the shift valve.
It is returned to the original transmission position by the pressure oil from (24) and the sequence valve (47) is returned to the original oil supply position (b), so that the hydraulic piston (37) returns to the pressurized state. .

In short, the main transmission device (3) and the sub transmission device (5) are switched by operating the shift valve (24). That is,
It is done with hydraulic power. And the first main transmission section (3a)
And the second auxiliary transmission section (5b) to the second main speed change unit (3b) or the first auxiliary transmission section (5a) is a neutral position located between the time of each switching between this and the shifting clutch (C ₂₎ Switching, the first main transmission section (3a) or the second auxiliary transmission section (5b) and the shift clutch (C ₂ ).
The transmission of the dynamic inertia of the mission constituent member located between the two is suppressed from being transmitted to the first main transmission section (3a) or the second sub transmission section (5b). That is, the synchronization of the first main transmission portion (3a) and the second auxiliary transmission portion (5b) is facilitated.

The forward / reverse switching device (4) is switched by an artificial operation force by swinging the forward / backward lever (36). However, only by operating the forward / reverse lever (36), the transmission cutting operation required for switching the switching gear (33) and the transmission entering operation after the switching is completed are automatically performed.

Each of the link type interlocking mechanism (15), (17), (19), (21),
A swing arm (51a) or (51b) or (5) that engages the free end side with the shifter (11a) or (12a) or (13a) or (14a)
1c) or (51d), a push / pull rod (53a) whose one end side is connected to the end of the rotation support shaft (52a) or (52b) or (52c) or (52d) of this swing arm protruding outside the mission case. )
Or (53b) or (53c) or (53d), the other end of this push-pull rod is connected and the mission case (2)
A rotating shaft (55a) or (55b) attached to the transmission case via a mounting member (54) so as to rotate around the lateral axis of the transmission case.
Alternatively, the rotary cylinder shaft (56a) or (56b) is used.

The oil passage forming member (23) includes a main body (23a) and the main body (23a).
And a lid plate (23b) superposed on the main body (23a) so as to close the oil passage forming groove.

The link-type interlocking mechanism (45) includes a push-pull rod (57) whose one end side is connected to the forward-reverse lever (36), and the mounting member (54) so as to rotate around the lateral axis of the transmission case. The rotary shaft (58) is attached, and the push-pull rod (59) has one end connected to the end of the rotary shaft (58) located inside the mission case.

In addition, (60) shown in FIG. 5 is an upper lid that closes the interlocking mechanism storage space formed by the mounting member (54), and (61) is an upper lid that closes the valve storage space formed by the mounting member (54). is there.

[Another embodiment]

The present invention can be applied to various work vehicles such as a truck and a lawn mower in addition to an agricultural tractor.

It should be noted that reference numerals are added to the claims for convenience of comparison with the drawings, but the present invention is not limited to the structures of the accompanying drawings by the entry.

[Brief description of drawings]

The drawings show an embodiment of a transmission structure for traveling of a work vehicle according to the present invention. Fig. 1 is a sectional view of a mission, Fig. 2 is a transmission system diagram, Fig. 3 is a hydraulic circuit diagram, and Fig. 4 is an interlocking mechanism. Perspective view of
FIG. 5 is a perspective view of the shift valve mounting portion, FIG. 6 is a side view of the hydraulic cylinder mounting portion, and FIG. 7 is a sectional view taken along the line VII-VII of FIG. (3a), (3b), (5a), (5b) …… Transmission unit, (11), (12), (13), (14) …… Shift gear, (16), (18), (20) , (22) …… hydraulic cylinder, (24) …… shift valve, (31), (32) …… coupling mechanism, (37) …… hydraulic piston, (39) …… control valve,
(49) …… Clutch control mechanism, (C ₂ ) …… Shift clutch.

Claims (2)

[Claims] 1. Two of the synchromesh type transmission parts (3a, 5a or 3b, 5b) which can be switched between two stages are arranged in a state of interlocking in series, and the transmission parts (3a, 5a or 3b, 5b) are arranged. ) Both of them are gear shift clutches on the transmission upper side or the transmission lower side.
(C ₂ ) is arranged, the shift gears (11), (13) of one of the transmission portions (3a), (5a) and the shift gears of the other transmission portions (3b), (5b).
A pair of hydraulic cylinders (16, 18 or 20, 22) for switching between (12) and (14), a hydraulic piston (37) for operating the shift clutch (C ₂ ), and the hydraulic cylinder (16 , 18 or
One shift valve (24) for controlling each of the shift gears (22, 22) is provided, and the shift clutch (C ₂ ) is linked to the disengagement operation of any of the shift gears (11, 12 or 13, 14). It automatically turns off, and the shift gear (11, 12 or
The hydraulic cylinder is brought into a state in which the speed change clutch (C ₂ ) is automatically turned on in association with the input operation of any one of 13, 14).
(16,18 or 20,22), the hydraulic piston (3
A clutch control mechanism (49) linked to the control valve (39) of (7) is provided, and the shift of the shift portion (3a, 3b or 5a, 5b) farther from the shift clutch (C ₂ ) is performed. Part (3a
Alternatively, the shift clutch is linked to the disengagement operation of 5b).
The transmission (3b or 5b) closer to (C ₂ ) is turned off,
Also, one of the hydraulic cylinders (16 or 20) is brought into a state in which the transmission section (3a or 5b) on the far side is linked to the entry operation of the transmission section (3b or 5b) on the near side and automatically enters the transmission section (3b or 5b) on the near side. A transmission structure for traveling of a work vehicle, which is provided with a linkage mechanism (31 or 32) that links a hydraulic cylinder (18 or 22) with the other hydraulic cylinder. 2. The traveling transmission structure according to claim 1, wherein the linkage mechanisms (31), (32) are hydraulic linkage mechanisms.