JPS62297561A - Hydraulic circuit structure for working truck - Google Patents

Abstract

PURPOSE:To obtain a hydraulic circuit for enabling the speed change operation with a single operational lever by constructing such that the working oil is fed to a sub-control valve and a drive/reverse switching valve then switchably fed from the drive/reverse switching valve to a main control valve and a reverse hydraulic clutch. CONSTITUTION:Pressure oil is fed from a pump 22 to a three position switching drive/reverse changeover valve 24 and a sub-control valve 26 for a sub- transmission. When the drive/reverse changeover valve 24 is switched to the derive position, the pressure oil is fed to a main control valve 23 so as to operate the main control valve 23 and the sub-control valve 26 to the positions (f1)-(f3) and H, L thus performing the speed change operation drive 1-6 speeds. When the first speed change lever is switched to the drive 1 position F1, second speed change operating section is interlocked to operate the drive/reverse changeover valve 24 to the drive position F. When the first speed change lever is operated to the drive 4-6 speed positions, the sub-control valve 26 is operated to the high speed position H.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention [Field of Industrial Application] The present invention includes a main transmission and a sub-transmission that are composed of a plurality of hydraulic clutches for shifting, and a The present invention relates to a hydraulic circuit structure for a working vehicle configured to selectively operate each hydraulic clutch by supplying hydraulic oil to perform gear shifting for traveling.

[Conventional technology]

The transmission structure of an agricultural combine harvester, which is one of the working vehicles, is disclosed in Japanese Utility Model Application Publication No. 142128/1983.In this, the engine power transmitted by the belt is transferred to a gear shift type sub-transmission with three stages, high, middle and low. The transmission is transmitted to the main transmission with three forward speeds and one reverse speed using a hydraulic clutch type, and the gears are changed. Since the hydraulic clutch type does not require any important operation of the main clutch, it is easier to operate and has less operating resistance than the gear shift type, so in recent years, a transmission structure in which the sub-transmission device is also configured as a hydraulic clutch type has been considered.

[Problem that the invention seeks to solve]

As mentioned above, if the auxiliary transmission is also a hydraulic clutch type, the control valve for the main transmission also incorporates the valve function for the auxiliary transmission, and by operating one control valve with one operating lever, both the main and auxiliary transmissions can be operated. It is also possible to enable the transmission to change speeds at the same time, which can be expected to further improve operability, but if many valve functions are incorporated into one control valve in this way, the spool of the control valve will have many functions. A boat would have to be provided, which would complicate the structure of the control valve itself, which could lead to a decrease in the precision of the control valve's work and to a decrease in the reliability of the control valve's operation.

Here, the object of the present invention is to: maintain reliability of the control valve;
The object of the present invention is to obtain a hydraulic circuit configuration in which both main and sub transmissions can be operated with one operating lever.

[Means for solving problems]

A feature of the present invention is that in the hydraulic circuit structure of a snow-covered work vehicle, hydraulic oil from a pump is supplied in parallel to the auxiliary control valve for the auxiliary transmission and the forward/reverse switching valve, and from the forward/reverse switching valve to the main The main control valve selectively supplies hydraulic oil to the forward hydraulic clutch of the transmission, and the reverse hydraulic clutch is configured to be able to selectively supply hydraulic oil, and its functions and effects are as follows. be.

[For production]

By distributing the valve functions to three control valves as described above, the number of boats to be provided in one control valve is reduced, and the structure of one control valve is simplified. In addition, since there is no mechanical linkage in the hydraulic circuit, the three control valves can be placed close to each other in any position, so these three control valves can be mechanically linked simultaneously with one operating lever. It is also possible to configure the device so that it can be operated.

〔Effect of the invention〕

As described above, the structure of the control valve can be simplified, and as a result, it is possible to simplify the structure of the control valve.
A hydraulic circuit structure that allows gear shifting to be performed using a single operating lever has been achieved, making it possible to improve operability. or,
These three control valves also have room to incorporate a boat for a hydraulically operated working device separate from the one used for traveling, and further improvements in functionality can be expected.

〔Example〕

EMBODIMENT OF THE INVENTION Hereinafter, an agricultural combine harvester which is one of the embodiments of the present invention will be described based on the drawings.

As shown in Figure 7, a pair of left and right crawler traveling devices (1
), (1) is equipped with a threshing device (2) in the center of the vehicle body (3), and a pulling device (4) and a reaping device (
5) A combine harvester is constructed by connecting the pre-harvest processing section (7), which is composed of the reaped grain culm conveying device (6), in a vertically movable manner.

Next, the traveling transmission system of the combine harvester will be explained in detail.
As shown in the figure, the engine (
The power from 8) is branched into a transmission system for the threshing device (2) and a transmission system for driving the traveling and reaping pre-processing parts. The latter branched power is the human power shaft (1) of the driving mission case (9).
0) through a tension clutch (11), and is further branched into a traveling system and a reaping section transmission system.

A part of the power of the human power shaft (10) is taken out to the PTO shaft (13) via a two-speed high/low gear transmission (12), from which a tension clutch-type reaping latch (14) is output.
) is transmitted to the human power shaft (15) of the reaping pre-processing section (7) by a belt. In addition, a part of the power of the human power shaft (10) is supplied to a secondary transmission (16) with two high and low gears, a main transmission with three forward gears (17), a hydraulic clutch for reverse (25), and a steering clutch. (18), left and right axles (
19), (19).

The main transmission (17) includes a multi-plate hydraulic clutch (20a) in the transmission system of the school gear pairs forming each gear stage.

(20b), (20c) are incorporated respectively, and these hydraulic flanges (20a), (20b), (20c) are installed.
The hydraulically operated traveling transmission device selectively supplies pressurized oil to perform transmission at a desired gear position. Also, like the main transmission (17), the auxiliary transmission (16) also has high and low 2
Two hydraulic clutches (21a) are installed in the school gear pair arranged in stages.

(21b) is a hydraulically operated type.

Next, the hydraulic path for supplying pressure oil to the hydraulic clutches (20), (21) of both transmissions (16), (17) and the reverse hydraulic clutch (25) will be described in detail as shown in FIG. Pressure oil from the pump (22) driven by the branched power of the engine (8) flows through the oil line (28).
, (29), and a 3-position forward/reverse switching valve (
24) and the auxiliary control valve (26) for the auxiliary transmission (16). In the state shown in Fig. 1, the forward/reverse switching valve (24) is operated to the neutral position (N), and the pressure oil is supplied to the hydraulic cylinder ( 44), which is then cut and operated.

Next, when the forward/reverse switching valve (24) is switched to the forward position (F), the pressure oil is sent to the main control valve (23) of the rotary set for the main transmission (17) via the oil path (30). . Then, the main control valve (23) and the sub control valve (26) are (r,
), (rz), (fi) and (11), (L
) to change gears from 1 forward gear to 6 forward gears. Next, when the forward/reverse switching valve (24) is switched to the reverse position (R), pressure oil is sent from the oil passage (31) to the reverse hydraulic clutch (25), which is engaged. Shifting during reverse movement can be performed in two high and low gears by switching the auxiliary control valve (26). In addition, an accumulator (27) is provided on the negative side of the forward/reverse switching valve (24), so that when the forward/reverse switching valve (24) is switched from the neutral position (N) to another position, the clutch operating pressure increases rapidly. This suppresses the shock when starting.

Next, these forward/reverse switching valve (24), main control valve (23)
, the operation structure of the auxiliary control valve (26) will be described in detail.As shown in Fig. 3.4.5, the first control valve (23)
The gear shift lever (32) is pivotally supported so that it can swing freely around the horizontal axis (P,) of the control section and also within a set range in the direction of the horizontal axis (P,), and the operating arm (32a) and an interlocking link (33), the main control valve (23) is interlocked with the main control valve (23). A retaining member (34) is attached around the horizontal shaft center (pz) provided near the center of the first shift lever (32).
The retaining member (34) is biased clockwise in FIG. 3 by a helical spring (35), and its rotation is prevented by contact with a stopper (36). It has a structure.

On the other hand, an L-shaped second shift operation part (37) is pivotally supported around the horizontal axis (P,) on the side wall near the first shift lever (32), and this second shift operation part (37) One end is operatively connected to the forward/reverse switching valve (24) via a link (38), and the other end is provided with a V-shaped locking portion (37a).

Further, on the opposite side of the second shift operation section (37), an arch-shaped auxiliary shift operation section (39) is pivotally supported around the horizontal axis (P,), and a helical spring (40) is used to shift the first shift. Lever (32)
It is biased toward the side and is operatively connected to the sub-control valve (26) via a link (41).

Figure 3 shows the state in which the first shift lever (32) is located at the neutral position (N), and the protrusion (34a) at the tip of the retaining member (34) provided on the first shift lever (32) is It is engaged in the locking part (37a) of the second shift operation part (37), the forward/reverse switching valve (24) is located in the neutral position (N), and the sub control valve (26) is in the low speed position (L). It is located in

From this state, move the first shift lever (32) along the lever guide (42) shown in FIG.
), the second shift operation section (
37) is also linked to move the forward/reverse switching valve (24) to the forward position (F
) is operated on. Furthermore, when the first gear shift lever (32) is switched to forward 2nd speed, 3rd gear position (FZ), (F The holding member (34) is separated from the locking part (37a) by the stopper (36), and the posture of the retaining member (34) with respect to the first gear shift lever (32) is maintained at this time, and the second gear shift operating part (37) and forward/reverse switching are Move the valve (24) to the forward position (F
) while moving the first gear lever (32) to 2nd forward gear.
It can be operated to 3rd speed position (Fz) or (F3).

Then, the first shift lever (32) is moved to the lever guide (
42) forward 4th, 5th, and 6th speed positions (Fa
), (Fs), and (F6), the first shift lever (32) pushes the auxiliary shift operation section (39) and operates the auxiliary control valve (26) to the high speed position (1(). When the first shift lever (32) is returned and operated from the second forward speed position (F2) to the first forward speed position (F,), the protrusion (34a) at the tip of the retaining member (34) becomes the second shift operation section. It re-engages with the locking portion (37a) of (37).Also, the reverse 1st and 2nd speed positions (R+).

The operation (R2) is also performed in the same manner as described above.

[Another example]

In the above embodiment, the main control valve (23) was a rotary set, but this was replaced with a forward/reverse switching valve (24) and a sub control valve (26).
It may also be a spool type.

The main control valve (23), the forward/reverse switching valve (24), and the sub control valve (26) are all set as a rotary set, and as shown in Fig. 8, the three (23), (24), and (26) are combined into As shown in Figures 9 and 10, the first gear shift lever (2
) and the main control valve (23) are not mechanically linked, but a potentiometer (43) that detects the operating position of the first shift lever (32), and a main control valve (23) based on the signal of this potentiometer (43). Servo motors (4
5) may be used as an electric type. In addition, the sub control valve (
26) is an electromagnetic type, and a limit switch (48) is provided in the sub-shift operation section (39).
Based on the ON-OFF signal from the sub control valve (2)
6) may be configured to be electrically operated.

In addition to the above-mentioned auxiliary transmission (16), there is also a high, medium and low 3
When a second auxiliary transmission is installed and the operation lever (46) of this auxiliary transmission is arranged in parallel with the first shift lever (32),
As shown in FIG. 11, when the operating lever (46) is operated to the high speed position (H) by providing a restraining device (47) shaped like a letter in plan view and sliding as the operating lever (46) is operated. It is also possible to improve safety by making it impossible to operate the first shift lever (32) to the high speed reverse position (R2).

[Brief explanation of the drawing]

The drawings show an embodiment of the hydraulic circuit structure of a working vehicle according to the present invention, in which Fig. 1 is a hydraulic pressure supply circuit diagram, Fig. 2 is a diagram showing the power transmission path and transmission structure, and Fig. 3 is a diagram showing the structure of the first gear shift. 4 is a front view of the vicinity of the first shift lever, FIG. 5 is a plan view of the vicinity of the first shift lever, and FIG. 6 is a front view of the vicinity of the first shift lever.
Side view showing a state in which the gear shift lever is operated to the forward side, No. 7
8 is a sectional view of a control valve showing another embodiment; FIGS. 9 and 10 are a side view and front view of the vicinity of the first gear shift lever showing another embodiment; FIG. The figure is a plan view of the vicinity of the first gear shift lever showing another embodiment.

Claims (1)

[Claims] It is equipped with a main transmission (17) and a sub-transmission (16) which are composed of a plurality of hydraulic clutches (20) and (21) for shifting, and each hydraulic clutch (20) is provided with hydraulic oil supplied from a pump (22). 20) and (21) are selectively actuated to perform a gear shift for traveling, the hydraulic circuit structure of a working vehicle is such that hydraulic oil from the pump (22) is used to shift gears for traveling. The hydraulic clutch (20) for forward movement of the main transmission (17) is supplied from the forward/reverse switching valve (24) in parallel to the auxiliary control valve (26) for the device (16) and the forward/reverse switching valve (24). ) A hydraulic circuit structure of a working vehicle configured to be able to selectively supply hydraulic oil to a main control valve (23) that selectively supplies hydraulic oil to a hydraulic clutch (25) for reversing.