JPH01126458A - Speed change operation structure - Google Patents

Abstract

PURPOSE:To prevent the occurrence of bad connection and to make the above structure in a compact size by forming a sliding spool of a sequence valve for operating a speed change clutch separately from a piston of a hydraulic cylinder. CONSTITUTION:As hydraulic cylinders 18, 20 operate for releasing the engagement of a shift gear, transmission portions 42a, 42b, 48a, 48b are operated to the side separating from receiving portions 42c, 48c by the cylinder operation. Sequence valves 41, 47 are switches from the clutch-on position to the clutch-off position by urging force of spring S3, S4, whereby a speed change clutch is switched from connection state to disconnection state. As the hydraulic cylinders 18, 20 operate the shift gear to the engagement position, the transmission portions 42a, 42b, 48a, 48b are forced to press the receiving portions 42c, 48c by the above cylinder operation, so that the sequence valves 41, 47 are switched from the clutch-off position to the clutch-off position to switch the speed change clutch from the disconnection state to the connection state.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a hydraulic cylinder for switching and operating a shift gear,
The present invention also relates to a speed change operation structure including a speed change valve for operating this hydraulic cylinder.

[Conventional technology]

In the above-mentioned speed change operation structure, conventionally, for example,
As shown in Japanese Patent No. 14239, a sequence valve for operating a transmission clutch is made from a piston of a hydraulic cylinder for changing a shift gear and a cylinder tube, and since the piston slides for operating a shift gear, By configuring the system so that the sequence valve is switched and the shift clutch is automatically operated when the shift gear is changed, the shift clutch is automatically switched and the shift is performed simply by switching the shift valve. It was configured so that it could be done.

[Problem that the invention seeks to solve]

In the conventional case, the reaction force of the shift gear operation acts on the hydraulic cylinder, and the piston of this hydraulic cylinder is the sliding spool of the sequence valve, so the sequence valve may become twisted or abnormally worn out as the shift gear is operated. However, poor coordination between the shift gear and the transmission clutch was likely to occur.

An object of the present invention is to provide a gear shifter that can change gears simply by switching valves, in a state where the aforementioned poor linkage is less likely to occur, and which is as compact as possible.

[Means for solving problems]

The characteristic configuration of the present invention is that in the above-mentioned speed change operation structure,
A sliding spool of a sequence valve for operating a speed change clutch is formed separately from the piston of the hydraulic cylinder, and a spring is provided for biasing the sliding spool to a clutch disengaged position, and the sliding spool or the sliding spool is A valve-side interlocking member connected to the moving spool is provided with a passive part, and when the shift gear is in the engaged position, it comes into contact with the passive part to press the sliding spool to the clutch engaged position, and When the shift gear is in the neutral position, the transmission part is spaced apart from the driven part to allow the sliding spool to be operated to the clutch disengaged position by the spring, and the transmission part is connected to the piston, or It is provided in the cylinder-side interlocking member connected to the piston. The functions and effects thereof are as follows.

[For production]

As the hydraulic cylinder operates to release the shift gear, the transmission part moves away from the passive part due to the cylinder operation, and the sequence valve is switched from the clutch engaged position to the clutch disengaged position by the biasing force of the spring. and the gear shifting clutch is switched from engaged to disengaged.

As the hydraulic cylinder operates the shift gear to the engaged position, the transmission part presses against the passive part to operate the cylinder, and this pressing action causes the sequence valve to switch from the clutch disengaged position to the clutch engaged position. When operated, the gear shifting clutch switches from disengaged to engaged. That is, the shift clutch is automatically disengaged when the hydraulic cylinder disengages the shift gear, and the shift clutch is automatically returned to the engaged state when the hydraulic cylinder engages the shift gear. The switching operation of the sequence valve for this purpose is performed while preventing the shift gear operation reaction force from acting on the sequence valve due to the contact and interlocking of the transmission part and the passive part, and the shift gear is in the neutral position. In order to provide interlocking flexibility where the transmission part and the passive part are separated, the operating stroke of the sliding spool of the sequence valve can be made smaller than the operating stroke of the piston of the hydraulic cylinder.

〔Effect of the invention〕

Because of the above-mentioned interlocking between the hydraulic cylinder and the sequence valve, the speed change operation can be easily performed by simply switching the speed change valve. Therefore, the reaction force of the shift gear operation does not act on the sequence valve, and the sequence valve can be prevented from becoming twisted or abnormally worn due to the reaction force of the shift gear operation, and the clutch control in conjunction with the change of the shift gear can be performed with high precision. It started to be done.

Moreover, due to the flexible interlocking between the transmission part and the passive part,
The stroke of the sliding spool required for switching the sequence valve is kept smaller than the operating stroke of the hydraulic cylinder.
It has become possible to make the sequence valve compact with a relatively small length in the spool sliding direction.

〔Example〕

Next, examples will be shown.

As shown in FIGS. 5 and 6, the rotational output of the engine (E) is introduced into the transmission case (2) via the main clutch (C+) and the input cylinder shaft (1), and the main transmission (S) The rotational output of the main transmission (S) is transmitted to the auxiliary transmission (5) via the forward/reverse switching device (4) and the shift clutch (Cg), and The output shaft (6) of this auxiliary transmission (5) is directly connected to the rear wheel differential mechanism (7), and also linked to the front wheel transmission shaft (9) via the gear transmission mechanism (8). This constitutes the transmission structure for traveling.

The main transmission (S) is a first main transmission section (Sa) that can be shifted in two stages.
) and a second main transmission section (Sb) are connected in series, and four stages of transmission are possible. The sub-transmission device (5) has a first sub-transmission section (5a) and a second sub-transmission section (5a) capable of two-speed shifting.
The auxiliary transmission section (5b) is connected in series, and the 4
This allows you to change the speed in stages. In other words, overall, the speed can be changed in 16 steps on each of the forward and reverse sides. The operating structure for this speed change is constructed as follows.

That is, as shown in FIG. 4, the shift gear (11) of the first main transmission section (5a) is connected to the first hydraulic cylinder (
16), the shift gear (1
2) with the sliding shifter (12a) and link type interlocking mechanism (
by a second hydraulic cylinder (18) via a
The shift gear (13) of the first main transmission section (Sa) is controlled by the third hydraulic cylinder (20) via a sliding shifter (13a) and a link type interlocking mechanism (not shown).
5b) shift gear (14) to the sliding shifter (14a)
and a fourth hydraulic cylinder (22) via a link type interlocking mechanism (not shown), and the first to fourth hydraulic cylinders (16),
One rotary speed change valve (24) is connected to (1B), (20), and (22) as shown in FIG. This variable speed valve (24) has one neutral operating position (
N) and 16 transmission operating positions (1) or XVI)
and these operating positions (N).

(1) or XvI), the operation position (N) or (I) or... (XV
The first to fourth hydraulic cylinders (16), (18) so that the main transmission (S) and the auxiliary transmission (5) are in the transmission cut state or the speed output transmission state corresponding to I).
, (20).

(22).

As shown in Figures 1 and 4, the second hydraulic cylinder (1
8) and the third hydraulic cylinder (20), a pair of hydraulic pistons (25a) for operating the hydraulic cylinder (18) or (20) to a neutral state.

(25b) or (26a), (26b), and the control valve (25a), (25b) or (26a), (26b) of this hydraulic piston (25a), (25b)
27) or (2 days) to the hydraulic cylinder (16) or (
22) and the interlocking mechanism (29) or (S0
) and link them. This interlocking mechanism (29) or (S0) consists of a sliding spool (27a) or (28a) of a control valve (27) or (28).
) to the operating rond part (29c) or (S0c)
This passive part (29c) or (S
A pair of transmission parts (29a) that come into contact with the transmission parts (29a).

(29b) or (S0a), (S0b) is provided in the piston (16a) or (22a) of the hydraulic cylinder (16) or (22), and the sliding spool (2
7a) or (28a) is the operating stroke of the piston (
16a) or (22a), and which is provided with an interlocking flexibility to make the stroke smaller than the operating stroke of the main transmission (S) or the sub-transmission (5), and which is farther from the transmission clutch (C2). When switching between the first main transmission part (Sa) or the second sub-transmission part (5b), the second main transmission part (Sb) or the first sub-transmission part (5a) which is closer to the transmission clutch (C2) - so that it can be switched to a neutral position from time to time. That is, when the shift gear (11) or (14) is in the occlusal position, either one of the transmission parts (29a) or (29b) or (S0a) or (S0b) is in contact with the passive part (29c) or (S0c). and press the sliding spool (27a) or (28a) to one of the cutting positions (a), and shift gear (
11) or (14) is in the neutral position, both (29a) and (29b) or (S0a) and (
S0b) is separated from the passive part (29c) or (S0c), and the sliding spool (27a) or (28a) is operated to the entering position (b) by the biasing force of the spring (S,) or (SZ). The transmission part (29
a) and (29b) or (S0a) and (S0b) are arranged. In other words, the piston (16a) or (2
As 2a) switches from the transmission position before the gear change toward the new transmission position, one of the transmission parts (29a),
(29b) or (S0a) or (S0b) is separated from the passive part (29c) or (S0c) and the control valve (27) or (28) is connected to the spring (Sl).
Or enter position 1 from one cutting position (a) for (SZ)! (b), a pair of hydraulic pistons (25
a) , (25b) or (26a) , (26b
) is driven to the approach side by pressure oil from the control valve (27) or (28), and the same hydraulic pump (P)
Despite being supplied with oil from these hydraulic pistons (25a), (25b) or (26a), (
26b) and the piston (16a) or (20a), one of the hydraulic pistons (25a) or (25b), (26a) or (26b) has priority over the pressure oil from the speed change valve (24). and hydraulic cylinder (18
) or (20) is pushed back to the neutral state. As the piston (16a) or (22a) moves to a new transmission position, the other transmission part (29b) or (29a) or (S0b) or (S0a) becomes the passive part (29c) or (S0c). Switch the control valve (27) or (28) from the on position (b) to the other off position (a) by touching the shift valve (27) or (28).
4) Pressure oil from piston (18a) or (20a)
Hydraulic piston (25a) that was operating by pushing it to the neutral position
Alternatively, push (25b), (26a) or (26b) back to the standby position and press the hydraulic cylinder (18).
Alternatively, (20) is operated to return it to its original transmission state.

The transmission clutch (C2) is configured to be operated by a hydraulic piston (S7) built into the clutch body as shown in FIG. 5, and as shown in FIGS. 1 and 4,
It is connected to the operation part of the control valve (S9) of the hydraulic piston (S7) by a pilot I-oil passage (40), and is configured so that the gear shift clutch (C2) is operated by pilot operation of the control valve (S9). A sequence valve (41) is connected to the third hydraulic cylinder (20), and an interlocking mechanism (42) is used to interlock the third hydraulic cylinder (20). A sequence valve (configured to supply pressurized oil to the clutch body via the control valve (S9) and the oil passage (46), and to release this oil supply and operate the gear shifting clutch (Ct))
47) is connected to the second hydraulic cylinder (18) and interlocked with the second hydraulic cylinder (18) by an interlocking mechanism (48). Each of the interlocking mechanisms (42) and (48) includes a sequence valve (41) or (
The sliding spool (41a) or (47a) of 47) is provided with a passive part (42c) or (48c) on the operating rod part, and the passive part (42c) or (48c)
A pair of transmission parts (42a) and (42b) that contact and act on
) or (48a), (48b) with hydraulic cylinder (
18) or (20) piston (18a) or (2
0a), the operating stroke of the sliding spool (41a) or (47a) is controlled by the piston (18a).
or (20a), the second main transmission section (S
b) or in conjunction with the switching of the first auxiliary transmission section (5a), the transmission clutch (CZ) is automatically engaged and operated. That is, when the shift gear (12) or (13) is in the occlusal position,
As shown in the figure, one of the transmission parts (42a) or (42b), or (48a) or (48b) is in contact with the passive part (42c) or (48c), and the sliding spool (41a) or ( 47a) is pressed to one clutch engagement position (b) and the shift gear (12) or (13) is in the neutral position, both transmission parts (42a) and ( 42b) or (48a) and (48b) are separated from the passive part (42c) or (48c)' and the sliding spool (
The transmission parts (42a) and (42b) or (48a) are configured to allow the transmission parts (41a) and (47a) to be produced in the clutch disengaged position (a) by the biasing force of the spring (S, ) or (S4). ) and (48b) are arranged. That is, the piston (18a) or (20a)
, one of the transmission parts (48a) or (48b) or (42a) or (42b) separates from the passive part (48c) or (48c) and the sequence valve (47) or (41) is activated by the spring. Due to the urging force of (S4) or (S,), one clutch is switched from the clutch engaged position (b) to the clutch disengaged position (a), and oil is drained from the operation chamber of the hydraulic piston (S7) and the hydraulic piston (
S7) is depressurized to the clutch disengaged state. As the piston (18a) or (20a) enters the transmission position and operates, the other transmission part (48b) or (48a) or (42b) or (42a) becomes the passive part (48c) or (42c). and move the sequence valve (47) or (41) to the clutch engaged position (
b), oil is supplied to the operation chamber of the hydraulic piston (S7), and the hydraulic piston (S7) is pressurized to the clutch engaged state.

When switching the first main transmission section (Sa), the interlocking mechanism (
29) and hydraulic pistons (25a) and (25b), the second hydraulic cylinder (18) is operated as described above, and the sequence valve (47) is switched off in the same way as when switching the second main transmission section (Sb). As a result, as the piston (16a) of the first hydraulic cylinder (16) switches from the transmission position before shifting toward the new transmission position, the hydraulic piston (S7) is depressurized, and the piston (16a) is moved to a new position. The hydraulic piston (S7) enters the transmission position and operates.
) returns to the pressurized state. Then, the second sub-transmission section (
5b), the interlocking mechanism (S0) and the hydraulic piston (26a).

(26b), the third hydraulic cylinder (20) is operated as described above and the sequence valve (41) is switched in the same manner as when the first sub-transmission section (5a) is switched.
As the piston (22a) of the fourth hydraulic cylinder (22) switches from the transmission position before shifting toward the new transmission position, the control valve (S9) moves to the clutch disengaged position, and the piston (22) moves to the new transmission position. As the clutch enters the transmission position and operates, the control valve (S9) returns to the clutch engagement position.

The switching gear (S3) of the forward/reverse switching device (4) is configured to be switched by a forward/reverse lever (S6) via a sliding shifter (S3a). An automatic switching valve (43) is connected to the hydraulic pistons (25a) and (25b).
), and the control valve (44), which is connected to the control valve (27) in a switching manner, is interlocked with the forward/reverse lever (S6) by means of the interlocking mechanism (45). In the interlocking mechanism (45), as the forward/reverse lever (S6) is swung, one of the transmission parts (45a) or (45b) of the m lever interlocking rods (49) is connected to the control valve ( 44) Oscillating spool (44a)
The control valve (44) is separated from the passive part (45c) provided in the control valve (44) due to the biasing spring (S,) and is switched from one of the open positions (a) to the open position (b), and the hydraulic piston (25a) or (25b) is the piston (18
a) to the neutral position to operate the sequence valve (47) from the negative clutch engagement position (b) to the clutch disengagement position (a) via the interlocking mechanism (48), and then As the lever (S6) moves to the forward or reverse position, the other transmission part (45b) or (4
5a) contacts the passive part (45c) to switch the control valve (44) to the other off position (a), and the piston (18a) is returned to the original transmission position by pressure oil from the variable speed pulp (24). The sequence valve (47
) to the original clutch engagement position (b).

In short, switching between the main transmission (S) and the sub-transmission (5) is performed by switching the transmission valve (24). In other words, it uses hydraulic power. And the first
When switching between the main transmission part (Sa) and the second auxiliary transmission part (5b), the second main transmission part (Sb) or the first auxiliary transmission part (5a) located between the main transmission part (Sa) and the second auxiliary transmission part (5b) are )
is switched to the neutral position, and the dynamic inertia of the Mitsushiran component located between the first main transmission section (Sa) or the second sub-transmission section (5b) and the transmission clutch (CZ) is changed to the first main transmission section (S).
a) or the second auxiliary transmission section (5b) is suppressed. That is, the first main transmission section (Sa)
This is intended to facilitate synchronization of the second auxiliary transmission section (5b).

The forward/reverse switching device (4) is switched using the forward/reverse lever (S6).
This is done using human operating force through the rocking operation. but,
Just by operating the forward/reverse lever (S6), the switching gear (
The transmission switching operation required for the switching in step S3) and the transmission switching operation after the switching is completed are both automatically performed.

The second hydraulic cylinder (18) and the third hydraulic cylinder (20
), hydraulic pistons (25a) and (25
b) or (26a) and (26b) and the piston (18
a) or (20a), the hydraulic piston (25a) and (25b) or (26a) and (
26b) and the cylinder tube is formed to be larger. That is, one hydraulic piston (2
Even if a slight misalignment occurs between the piston chamber equipped with 5a) or (26a) and the piston chamber equipped with the other hydraulic piston (25b) or (26b), the hydraulic pistons (25a) and (26b) caused by this 25b) or (26a
) and (26b) and piston (18a) or (20a
) to avoid complications.

In addition, (S8) shown in FIG. 4 is a shift clutch (C2).
This is a modulation valve to gradually increase the input operating pressure.

[Another example]

The valve cases of the sequence valves (41) and (47) are also formed separately from the hydraulic cylinders (18) and (20), and an interlocking mechanism is provided between the sequence valve and the hydraulic cylinder, and the passive parts (42c), ( 45c) as the valve side interlocking member, and the transmission parts (42a) and (42b)
, (45a), and (45b) may be provided in the cylinder-side interlocking member, respectively.

In addition to agricultural tractors, the present invention can also be applied to various work vehicles such as transport vehicles and lawn mowers.

Incidentally, although reference numerals are written in the claims section for convenient comparison with the drawings, the present invention is not limited to the structure shown in the accompanying drawings.

[Brief explanation of the drawing]

The drawings show an embodiment of the speed change operation structure according to the present invention, and the first embodiment
The figures are cross-sectional views of the hydraulic cylinder and valve, Figures 2 and 3.
The figure is a sectional view of the sequence valve, Figure 4 is a hydraulic circuit diagram,
FIG. 5 is a sectional view of the mission, and FIG. 6 is a transmission system diagram. (12), (13)...Shift gear, (1
8), (20)...Hydraulic cylinder, (18
a) , (20a)...Piston, (41)
, (47)...Sequence valve, (41
a), (47a)...Sliding spool, (4
2a), (42b), (48a), (48
b) ...=transmission part, (42c), (48c)・
...Passive part, (a) ...Clutch disengaged position, (b) ...Clutch engaged position, (Ct)
・・・・・・Shift clutch, (S3), (S4)・
·····spring.

Claims (1)

[Claims] Hydraulic cylinders (18), (20) for switching shift gears (12), (13), and this hydraulic cylinder (
18), a shift operation structure provided with a shift valve (24) for operating the shift clutch (C_2), and a sliding spool (41a) of the sequence valve (41) and (47) for operating the shift clutch (C_2); (47a) to the hydraulic cylinder (1).
8), formed separately from the pistons (18a), (20a) of (20), and the sliding spools (41a), (47a)
A spring (S_
3), (S_4) is provided, and the sliding spool (41a)
, (47a), or the sliding spool (41a),
The passive part (42c) is attached to the valve side interlocking member connected to (47a).
), (48c), the shift gear (12),
(13) is in the occlusal position, the passive part (42c
), (48c) and said sliding spool (41a)
, (47a) to the clutch engagement position (b), and the shift gears (12), (13) are in the neutral position, the shift gears (42c), (48c) are spaced apart from the passive parts (42c), (48c). The transmission parts (42a), (42b) are arranged so as to allow the sliding spools (41a), (47a) to be operated to the clutch disengaged position (a) by the springs (S_3), (S_4). , (48a
), (48b) as the pistons (18a), (20a)
Or, a speed change operation structure provided in a cylinder-side interlocking member connected to the pistons (18a) and (20a).