JPH0534554B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention comprises a main transmission device and a sub-transmission device that are composed of a plurality of hydraulic clutches for shifting, and which is equipped with a main transmission device and a sub-transmission device that are composed of a plurality of hydraulic clutches for shifting. The present invention relates to a hydraulic circuit structure for a working vehicle configured to selectively operate each hydraulic clutch to change gears 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 case, the engine power transmitted by the belt is transferred to a gear shift type sub-transmission with three stages of high, middle and low. The transmission is transmitted to a 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 involve the on/off operation of the main clutch, it is easier to operate and has less operational 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, the main and auxiliary transmissions can be operated. It is also possible to simultaneously perform gear shifting operations on both transmissions, which can be expected to further improve operability; however, incorporating many valve functions into one control valve in this way will cause the control valve spool to It became necessary to provide a large number of ports, which led to the complexity of the structure of the control valve itself, which could lead to a decrease in the precision of the control valve's work and a decrease in the reliability of the control valve's operation. .

An object of the present invention is to obtain a hydraulic circuit configuration that allows both main and sub transmissions to be operated with one operating lever while maintaining the reliability of the control valve.

[Means for solving problems]

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

[Effect]

By distributing the valve functions to three control valves as described above, the number of ports 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, it is possible to simplify the structure of the control valve, thereby obtaining a hydraulic circuit structure that allows gear shifting with a single operating lever without impairing the reliability of the control valve operation, thereby improving operability. I am now able to improve my skills. Additionally, there is room for a port for a hydraulically operated working device other than the one for traveling to be incorporated into these three control valves, and further improvement 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 FIG.
A combine harvester is constructed by mounting a reaping pre-processing section 7, which is composed of a lifting device 4, a reaping device 5, and a reaped grain culm conveying device 6, connected to the front part so as to be able to move up and down.

Next, to explain the traveling transmission system of the combine in detail, as shown in FIG. transmission system. The latter branched power is transmitted to the input shaft 10 of the traveling transmission case 9 via a belt via a tension clutch 11, and then further branched to the traveling system and the reaping section transmission system.

A part of the power from the input shaft 10 is taken out to the PTO shaft 13 via a two-speed high/low gear transmission 12, and from there is transferred to the pre-reaping treatment section 7 via a tension clutch type reaping clutch 14. input shaft 15
is transmitted by the belt. In addition, a part of the power of the input shaft 10 is transmitted to a sub-transmission device 16 with two high and low gears, a forward gear 3
The left and right axles 1 are connected to the left and right axles 1 through the main transmission 17, the reverse hydraulic clutch 25, and the steering clutches 18, 18.
9, 19.

The main transmission 17 includes a multi-plate hydraulic clutch 20a, 2 in a transmission system of a pair of regular gears forming each gear stage.
The hydraulic clutches 20a, 20b and 20c are assembled into a hydraulically operated traveling transmission that selectively supplies pressure oil to these hydraulic clutches 20a, 20b and 20c to perform transmission at a desired gear position. Also, like the main transmission 17, the sub-transmission 16 is of a hydraulically operated type in which two hydraulic clutches 21a and 21b are incorporated into a pair of regular gears forming two high and low gears.

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 driven pump 22 passes through oil passages 28 and 29 and is sent to a three-position forward/reverse switching valve 24 and an 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 applied to the hydraulic cylinder 44 which cuts and operates the reaping clutch 14 which is biased toward the entry side.
It is supplied to and is operated by cutting.

Next, when the forward/reverse switching valve 24 is switched to the forward position F, the pressure oil is sent to the rotary main control valve 23 for the main transmission 17 via the oil passage 30. Then, the main control valve 23 and the sub control valve 26 are set to f ₁ ,
The f ₂ , f ₃ , H, and L positions are operated to perform a speed change operation 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, and the clutch is engaged. When the vehicle is traveling in reverse, the speed can be changed between two high and low speeds by switching the sub-control valve 26. Also, the forward/backward switching valve 24
An accumulator 27 is provided on the primary side to prevent the clutch operating pressure from rising rapidly when the forward/reverse switching valve 24 is switched from the neutral position N to another position, thereby suppressing the shock at the time of starting.

Next, these forward/reverse switching valve 24, main control valve 2
3. To explain in detail the operation structure of the sub control valve 26, as shown in FIGS. 3, 4 and 5, the main control valve 23
The first gear shift lever 32 is pivotably supported around the horizontal axis _P1 of the control section, and also swingable within a set range in the horizontal axis _P1 direction, and the operating arm 32a and It is interlocked and connected to the main control valve 23 via an interlocking link 33. The engaging member 34 is pivotally supported around a horizontal axis P ₂ provided near the center of the first shift lever 32.
In Fig. 3, the spiral spring 3 is rotated clockwise.
At the same time, the rotation is energized by the stopper 36.
The structure is such that contact is prevented by.

On the other hand, an L-shaped second shift operating section 37 is pivotally supported on the side wall near the first shift lever 32 around a horizontal axis _P3 , and one end of this second shift operating section 37 is connected to the side wall near the first shift lever 32. It is interlocked and connected to the forward/reverse switching valve 24, and has a V-shaped locking portion 37a at the other end. Further, on the opposite side of the second shift operation section 37, an arch-shaped sub-shift operation section 39 is pivotally supported around the horizontal axis _P4 , and a helical spring 40 is attached to the first shift lever 39.
2 side, and is interlocked and connected to the sub-control valve 26 via a link 41.

FIG. 3 shows a state in which the first shift lever 32 is located at the neutral position N, and the protrusion 34a at the tip of the engagement member 34 provided on the first shift lever 32 is the locking portion of the second shift operation section 37. 37a, the forward/reverse switching valve 24 is located at the neutral position N, and the auxiliary control valve 26
is located at low speed position L. From this state, the fifth
When the first shift lever 32 is switched to the forward first speed position _F1 along the lever guide 42 shown in the figure,
As shown in FIG. 6, the second shift operating section 37 is also operated in conjunction with the forward/reverse switching valve 24 to the forward position F.
Further, when the first shift lever 32 is switched to forward 2nd speed and 3rd speed positions F ₂ and F ₃ , the protrusion 34 a at the tip of the engagement member 34 engages the locking portion 37 of the second shift operation portion 37 .
a, the posture of the engaging member 34 with respect to the first shift lever 32 is maintained by the stopper 36, and the first shift is performed while leaving the second shift operation part 37 and the forward/reverse switching valve 24 in the forward position F. The lever 32 can be operated to forward 2nd speed and 3rd speed positions F ₂ and F ₃ .

Then, the first shift lever 32 is moved forward along the lever guide 42 to the forward 4th, 5th, and 6th speed positions.
The first shift lever 32 operated to F ₄ , F ₅ , and F ₆ pushes the auxiliary shift operation section 39 to operate the auxiliary control valve 26 to the high speed position H. Next, the first gear shift lever 3
2 is returned and operated from the forward 2nd speed position F ₂ to the forward 1st speed position F ₁ , the protrusion 34 a at the tip of the engagement member 34 engages the locking portion 3 of the second shift operation section 37
7a again. Also, reverse 1st speed, 2nd speed
The speed positions R ₁ and R ₂ are operated in the same manner as described above.

[Another example]

In the above-mentioned embodiment, the main control valve 23 was of the rotary type, but this was replaced with the forward/reverse switching valve 24 and the sub-control valve 2.
It may be a spool type like 6.

The main control valve 23, the forward/reverse switching valve 24, and the auxiliary control valve 26 are all rotary type, and as shown in FIG. It may also be a model.

As shown in FIGS. 9 and 10, the first shift lever 32 and the main control valve 23 are linked not mechanically, but by a potentiometer 43 that detects the operating position of the first shift lever 32, and this potentiometer. 43
It may be an electric type configured with a servo motor 45 that operates the main control valve 23 based on the signal.
Further, the sub-control valve 26 is of an electromagnetic type, and a limit switch 48 is provided in the sub-shift operation section 39, so that the sub-control valve 26 is electrically operated based on an ON-OFF signal from the limit switch 48. Good too.

In addition, in addition to the above-mentioned sub-transmission 16, a second sub-transmission with three high, medium and low gears is installed, and the operating lever 46 of this sub-transmission is arranged parallel to the first shift lever 32, as shown in FIG. As shown, the operating lever 46
A restraining device 47 having an L-shape in plan view that slides as the operation lever 46 is operated is provided to prevent the first gear shift lever 32 from being operated to the high-speed reverse position _R2 when the operating lever 46 is operated to the high-speed position H, thereby making it safe. It is also possible to improve sexual performance.

[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 the structure of the transmission,
Figure 3 is a side view of the vicinity of the first gear shift lever, Figure 4 is a front view of the vicinity of the first gear lever, Figure 5 is a plan view of the vicinity of the first gear lever, and Figure 6 is a side view of the vicinity of the first gear lever. 7 is an overall side view of the combine harvester, FIG. 8 is a sectional view of the control valve showing another embodiment, and FIGS. 9 and 10 are the first gear shift showing another embodiment. Side view and front view near the lever,
FIG. 11 is a plan view of the vicinity of the first gear shift lever showing another embodiment. 16...Sub-transmission device, 17...Main transmission device, 2
0, 21...Hydraulic clutch, 22...Pump, 2
3... Main control valve, 24... Forward/forward switching valve, 25...
...Hydraulic clutch for reverse movement, 26...Sub-control valve.

Claims (1)

[Claims] 1. A main transmission device 17 and a sub-transmission device 16 are provided which are composed of a plurality of hydraulic clutches 20 and 21 for shifting, and each hydraulic clutch 20 and 21 can be selectively operated by supplying hydraulic oil from a pump 22. A hydraulic circuit structure for a working vehicle configured to operate to change gears for traveling, the pump 22
Supplying hydraulic oil from the auxiliary transmission device 16 to the auxiliary control valve 26 and the forward/reverse switching valve 24 in parallel,
The main control valve 23 selectively supplies hydraulic oil from the forward/reverse switching valve 24 to the forward hydraulic clutches 20 of the main transmission 17 and the reverse hydraulic clutch 25 so that the hydraulic oil can be selectively supplied. Hydraulic circuit structure of a certain work vehicle.