JPH0517985B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a hydraulic clutch for a plurality of transmissions,
It is equipped with a transmission that is selectively activated by pressure oil supplied from a control valve to perform multi-speed gear shifting, and the power from the transmission is transmitted through a pair of left and right steering clutches to a pair of left and right traveling gears. The present invention relates to an automatic gear shift operation structure for a work vehicle in which the vehicle body is configured to be able to perform turning operations by transmitting power to each of the steering clutches and disengaging one of the steering clutches and cutting off the power transmission to one of the traveling devices.

[Conventional technology]

An agricultural combine harvester is an example of a work vehicle equipped with the above-mentioned traveling transmission structure.

In such combine harvesters, when the operator specifies a set gear shift position, the traveling transmission is shifted from a neutral state to the set gear position in stages after a set period of time to the next gear shift position. Some vehicles are equipped with a control means for automatically operating a control valve for a transmission.

[Problem to be solved by the invention]

When equipped with a control means as described above, if a turning operation is performed during automatic gear shifting by this control means,
The aircraft appears to be turning while changing its traveling speed.

Especially during acceleration, if you disengage the steering clutch to stop the traveling gear on one side and perform a turning operation, the aircraft will suddenly change direction due to the traveling gear on the other side being driven. There are problems in running stability and safety. Such a problem is particularly important in agricultural combines and the like that run on fields that are more unstable than paved roads.

An object of the present invention is to improve running stability and safety in a work vehicle equipped with a control means for automatic transmission as described above.

[Means to solve the problem]

The feature of the present invention is that the above-mentioned automatic shift operation structure for a work vehicle is configured as follows. In other words, it is equipped with a detection means for detecting that a turning operation is being performed during an automatic gear shift operation, and maintains the shift position at which the detection means is in the detection state until the detection means is in a non-detection state. A restraining means is provided for restraining the control means so that the gear shifting operation is performed to the next shifting position after a set time from the non-detection state.

[Effect]

If the above-mentioned detection means and restraint means are provided, when a turning operation is performed during an automatic gear shift operation by the control means, the detection means enters a detection state, and the automatic gear shift operation is temporarily interrupted by the restraint means that senses this. At the same time, the shift position of the transmission device at the time when the turning operation was performed is held, and the work vehicle turns at this shift position. When the detection means senses that the turning has ended, based on this, the check means returns the counting operation of the set time in the automatic gear shift operation in the control means to the state at the start of counting, and then checks the automatic gear change. unlock. In this way, at the end of the turn, the automatic gear change operation by the control means will be in the state immediately after the shift operation of the transmission to the shift position held during the turn, and after a set time from the end of the turn, the automatic gear change operation will be performed. are sequentially shifted to the next shift position by the control means.

〔Effect of the invention〕

As explained above, even if a turning operation is performed during automatic gear shifting, the work vehicle will turn at a constant speed at a certain shift position, so the running stability and safety of the work vehicle at this time is ensured. The day came. If a gear shift operation is performed immediately after the end of a turn when the aircraft is in an unstable state, there is a risk that the gear shift shock will cause the aircraft to lose its balance. Since the gear shift position is held in the middle, the balance of the aircraft is not lost, and running stability and safety can be further improved.

In addition, in the case of a combine harvester, etc., after turning at the edge of a ridge, the direction of the machine is corrected to the left or right, and row alignment is performed to align the reaping part with the row of planted grain culms. Therefore, if the vehicle travels at a constant speed change position for a set time even after turning is completed as in the present invention, it becomes easier to perform line adjustment at this constant speed.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS An agricultural combine harvester, which is one embodiment of the invention, will be described below based on the drawings.

As shown in FIG.
The agricultural combine harvester is equipped with a reaping pre-processing section 7, which is made up of a lifting device 4, a reaping device 5, a reaped grain culm conveying device 6, etc., and is movable up and down at the front.

Next, to explain the power 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 pretreatment 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. A part of the power of the input shaft 10 is transmitted to a three-stage auxiliary transmission 16, a main transmission 17 with three forward speeds and one reverse speed, and a steering clutch 18.
The signal is transmitted to the left and right axles 19 through 18.

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, .

a gear transmission device 12 of the reaping pretreatment section transmission system;
When operating the auxiliary transmission 16 of the traveling system, the tension clutch 11 is operated, but the main transmission 17 is operated only by the control valve 21 incorporated in the hydraulic circuit for clutch operation shown in FIG. It is done by.

That is, by switching the control valve 21 to the F ₁ , F ₂ , F ₃ and R positions, the first forward speed hydraulic clutch 20a and the second forward speed hydraulic clutch 20
b. Pressure oil is selectively supplied to the forward three-speed hydraulic clutch 20c and the reverse hydraulic clutch 20d to obtain a clutch engaged state of the transmission system, and to set the control valve 21 to the N position. By switching, the pressure oil from the full hydraulic clutches 20a, 20b, . Further, an accumulator 22 is connected to the primary side of the control valve 21, and suppresses a sudden increase in the clutch operating pressure when the gear is changed from the neutral position N, thereby alleviating the shock of starting the vehicle. .

Next, the flow of operation of the electric circuit type control device 23, which is one of the control means 23 that automatically operates the control valve 21, will be described. For example, when starting from a stopped state and automatically shifting to the third forward speed, As shown by the solid line in FIG. 1, the control device 23 shifts from the neutral position N to the first forward speed _F1 , then after a set time t, shifts to the second forward speed _F2 , and again after the set time t, moves forward to the first forward speed F2. The control valve 21 is operated in stages by the servo motor 24 so as to shift to the third speed _F3 . A flowchart of the automatic shift operation performed by the control device 23 in this manner is shown in FIG. The gear shifting operation to each gear shifting position F ₁ , F ₂ , F ₃ corresponds to steps (S ₁ ), (S ₂ ), (S ₃ ), and the set time t
The counting is performed in a loop from steps (S ₅ ) to (S ₆ ) and from (S ₈ ) to (S ₉ ).

When the steering clutches 18, 18 in the traveling transmission case 9 are operated to disengage the steering clutches 18, 18 in order to turn during automatic gear shifting as described above, the control device 23 is detected by a sensor which is a detection means 25 attached to the traveling transmission case 9. It is input that the detection state is in the state. For example, as shown by the dashed line in Fig.
At time a during the count of the set time t from speed _F1 to forward second speed _F2 , the state of first forward speed _F1 is maintained until time b when the turn ends and the sensor 25 becomes non-detecting state. . Then, after a set time t from the time point b when the turn is completed, the speed is changed to the second forward speed _F2 . In this way, the check operation for temporarily interrupting the automatic gear shift operation is performed at steps (S ₄ ), (S ₆ ), (S ₇ ), and (S ₉ ) in the flowchart of FIG. In the non-detection state, that is, when the steering clutches 18 and 18 are in the disengaged state, L, which counts the set time t, is always held at zero in steps (S ₄ ) and (S ₇ ).
It does not proceed to the next gear shifting operation steps (S ₂ ) and (S ₃ ). Thereafter, after the steering clutches 18, 18 are in the engaged state, the set time t is counted from zero by L, and the process proceeds to steps (S ₂ ) and (S ₃ ).

[Brief explanation of drawings]

The drawings show an embodiment of the automatic shift operation structure for a working vehicle according to the present invention, FIG. 1 is a diagram showing the relationship between time and shift position during automatic shift, FIG. 2 is a flowchart of operation control, and FIG. 3 4 is a power transmission system diagram, FIG. 4 is a hydraulic supply system diagram, and FIG. 5 is an overall side view of the combine harvester. 1... Traveling device, 17... Transmission device, 18...
Steering clutch, 20...Hydraulic clutch, 21...
control valve, 23... control means, 25... detection means,
t...Setting time.

Claims (1)

[Claims] 1 Hydraulic clutches 20a, 20 for multiple speed changes
Transmission device 1 that selectively operates b... by supplying pressure oil from a control valve 21 to perform multi-stage gear shifting.
7, transmits the power from the transmission 17 to each of the pair of left and right traveling devices 1 via the pair of left and right steering clutches 18, and
As the power transmission to one of the traveling devices 1 is cut off, the aircraft is configured to be capable of turning operation, and the transmission 17 shifts from the neutral state to the next shift position after a set time t. and an automatic gear shifting operation structure for a work vehicle having a control means 23 for operating the control valve 21 so that the gear shifting operation is performed stepwise to a set gear position, and a turning operation is performed during the automatic gear shifting operation. The shift position at which the detection means 25 enters the detection state is maintained until the detection means 25 enters the non-detection state, and the next shift position is set after the set time t after the non-detection state. An automatic gear shift operation structure for a working vehicle, comprising a restraining means for restraining the control means 23 so that the gear shift operation is performed to a gear shifting position.