JPH05246258A - Pto speed change control device for tractor - Google Patents

Abstract

PURPOSE:To lighten shift load by shortening the shift stroke of a control lever in a speed change control device where a clutch is engaged/disengaged by a single control lever while being interlocked with speed change operations. CONSTITUTION:This is a PTO speed change device for a tractor where a control means 3 for a PTO clutch lever 2 which engages/disengages the main clutch of a power takeout means PTO, comprises a switching means 4 interlocked with engagement/disengagement with the PTO speed change means of the power takeout means PTO switched over to a high speed position H/a low speed position L.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a PTO gear shift operating device for a tractor, in which a single operating lever is used for interlocking the power take-out device with the on / off of the power take-off device.

[0002]

2. Description of the Related Art In a gear shift operation device that engages and disengages a clutch and shifts with a single operation lever, the shift stroke of the operation lever becomes long. Shift load tends to be large.

[0003]

According to the present invention, an operating device 3 of a PTO clutch lever 2 for turning on and off a main clutch 1 of a power take-off device PTO is attached to a PT of the power take-out device PTO.
P of a tractor provided with a switching device 4 for switching the O transmission 5 between a high speed position H and a low speed position L to interlock on and off.
The TO gear shift operation device is configured.

[0004]

When the switching device 4 is operated to the high speed position H, the PTO transmission device 5 can be switched between the neutral position N and the high speed position H by operating the PTO clutch lever 2. Therefore, when the PTO clutch lever 2 is operated from the disengaged position to the engaged position, the PTO transmission 5 is operated to enter the high speed position H during disengagement of the main clutch 1 to engage the main clutch 1. Operated. When the main clutch 1 is engaged, the power takeoff device PT
O is transmitted in the high speed range.

On the contrary, when the switching device 4 is operated to the low speed position L, the main clutch 1 and the low speed position L of the PTO transmission 5 are interlocked by the operation of the PTO clutch lever 2 in the same manner. In this way, the operation of the main clutch 1 and the operation of the PTO transmission 5 between the shift positions H and L selected to be high and low and the neutral position are performed by operating the PTO clutch lever 2. Since the PTO clutch lever 2 does not have a long shift stroke and is interlocked with the PTO transmission 5, the operation load is small, the configuration can be simplified, and the shift can be performed lightly. It can be operated.

[0006]

Embodiments Regarding the relationship between the PTO clutch lever 2 on the operation panel 6 and the switching device 4, the PTO clutch lever 2 is rotatable in the front-rear direction around the lever shaft 7 and can rotate the cam plate 8 integrally. .. The corrugated cam edge 9 formed along the lower edge of the cam plate 8 causes the cam roll 12 of the arm 11 rotatable about the arm shaft 10 to slide. By swinging the shifter arm 14 connected to the arm 11 via the rod 13 against the spring 15, the shifter pin 16 and the clutch shifter 17 are swung, and the power take-out device P is moved by the PTO clutch lever 2.
The main clutch 1 of the TO can be turned on and off.

A cam groove 18 is formed in a wavy shape on the cam plate 8, and a cam roll 20 of a switching arm 19 which is rotatable about the same axis 10 as the arm 11 is fitted into the cam groove 18. , The PTO clutch lever 2 is pivoted to swing around the arm shaft 10. An arcuate pin groove 21 is formed in a vertical direction on a side of the switching arm 19 opposite to the cam roll 20 with respect to the arm shaft 10, and a lower end of a switching rod 22 that is operated vertically with respect to the operation panel 6 is provided. The switching pin 23 is fitted and guided in the pin groove 21. A link rod 24 is connected to the switching pin 23 so that the PTO
It is interlocked with a shift shifter 25 that shifts the transmission 5. 26 is a shifter pin. When the switching rod 22 is pulled upward, the switching pin 23 is moved to the upper end portion of the pin groove 21, and the PTO transmission 5 is switched to the low speed position L, and when it is pushed downward, it is moved to the high speed position H. Switch to the shift process. These switching positions are determined by the locking pieces 2 on the operation panel 6.
By rotating 7 to engage with the notches 28 and 29 of the switching rod 22, the vertical switching movement of the switching rod 22 can be locked and fixed.

Cam edge 9 for guiding the cam rolls 12, 20
And the cam groove 18 are set so as to have a phase as shown in FIG. The gear shifting operation is usually performed in the roll position
D is performed, but the engine 30 is started at the roll position E.
In step 1, the safety switch 31 is turned on. In the tractor vehicle body, the clutch housing 33, the intermediate transmission case 34, and the like are integrally connected from the rear engine 30 to the front front transmission case 32, and the front wheel 35 and the rear wheels are driven by the engine 30. Three
6 to travel, and also the PT of the front transmission case 32.
The O-axis 36 is transmitted. A steering wheel 37 at the front of the vehicle body is used to steer the rear wheels 36. 38 is a cockpit and 39 is a hood.

Regarding the transmission structure of the power take-off device PTO,
As described above, the main clutch 1 is provided in the clutch housing 33 so that the main clutch 1 can be turned on and off by the clutch shifter 17, and the transmission shaft 40 of the power take-off device PTO, the PTO transmission 5, and the PTO shaft 36 are provided via the main clutch 1. Etc. can be transmitted forward. The PTO transmission 5 includes a front transmission case 3
2, the transmission gear 42 of the PTO shaft 36 is connected to the gear 41 at the front end of the PTO transmission shaft 40.
The PTO shaft 36 can be switched from the neutral position N to the low speed position L or the high speed position H by switching and meshing with.

Regarding traveling transmission, from the output shaft 43 in the clutch housing 33 transmitted from the engine 30,
The hydraulic continuously variable transmission HST in the central transmission case 34 is transmitted, and the continuously variable transmission is performed by the gear shifting operation of the hydraulic continuously variable transmission HST from the neutral position to the forward position or the reverse position. , The left and right front wheels 35 are transmitted through a transmission shaft 48 rotatable around the PTO transmission shaft 40, a traveling transmission shaft 45 in the front transmission case 32, a differential gear mechanism 46, and the like. About the auxiliary transmission,
A shift gear 47 on the traveling transmission shaft 45 and a gear mesh 49 integral with the transmission shaft 48 switch the traveling transmission between a low speed position and a high speed position. The speed change arm 44
Is performed by operating the petal 68.

The rear wheel transmission for transmitting the rear wheel 36 is
From the gear 50 of the traveling transmission shaft 45, through the gear 51 rotatable with respect to the transmission shaft 48, the gear 5 of the rear wheel transmission shaft 52.
3 is meshed with the rear wheel transmission shaft 52, and the left and right rear wheels 36 are transmitted from the rear wheel transmission shaft 52 via the two-wheel and four-wheel drive switching device 54, the rear wheel transmission shaft 55, the differential gear mechanism 56, and the like. ..
The two-wheel-drive / four-wheel drive switching device 54, in the form of a full-time four-wheel drive, automatically performs two-wheel drive by the front wheels 35 (two-wheel drive) and front wheels 35 by the difference in rotation between the rear-wheel transmission shafts 52 and 55. It is adapted to switch to four-wheel drive (four WD) by the rear wheels 36.

In the above construction, the stroke of the PTO clutch lever 2 is made as small as possible,
Therefore, in order to reduce the operation load, it is preferable to set the inclination of the cam edge 9 and the cam groove 18 as gently as possible. PT
ON / OFF of the main clutch 1 by the O-clutch lever 2,
Since the switching between the low speed position L and the high speed position H by the switching rod 22 is performed independently, the operability of the main clutch 1 of the power take-out device PTO, which is frequently used, is good.

Further, by the locking piece 27, the switching rod 22
Since the switching position of can be fixed, high speed position H
It is possible to prevent using both the low speed position L and the low speed position L. By stepping on the clutch petal 57 of the main clutch 1 in the hydraulic circuit that is also mounted on the engine 30 and is used for raising and lowering the working machine, which is also used as the charge pump of the hydraulic continuously variable transmission HST, The running brake 58 and the unload valve 59 of the hydraulic continuously variable transmission HST are interlocked to operate.

The control floor 60 is provided with a brake petal 61 for operating a pair of left and right steering brakes and a clutch petal 57, and the PTO clutch lever 2 is also operated by stepping on the clutch petal 57. The clutch shifter 17 is activated to disengage the main clutch 1. Reference numeral 62 is a rod that interlocks between the clutch petal 57 and the shifter arm 14, 63 is a brake arm of the traveling brake 58, and interlocks with the clutch petal 57 by a rod 64. The traveling brake 58 is interlocked to simultaneously brake the left and right steering brakes. An unload valve 59 is provided in the hydraulic circuit in the hydraulic continuously variable transmission HST, and the clutch petal 57 allows the rod 65, the spring 66,
The unload valve 59 is operated via the bell crank 67 or the like to reduce the load due to the charge pressure acting on the hydraulic pump P, reduce the load on the engine when the main clutch 1 is disengaged, and improve the startability of the engine 30. is doing. Improves startability at low temperatures.

[Brief description of drawings]

FIG. 1 is a side view of a PTO clutch lever portion.

FIG. 2 is a plan view of the lever guide portion.

FIG. 3 is a diagram showing the cam phase relationship.

FIG. 4 is a transmission mechanism diagram.

FIG. 5 is an operation interlocking diagram of the clutch petal.

FIG. 6 is a side view of the whole.

[Explanation of symbols]

 1 Main Clutch 2 Clutch Lever 3 Operating Device 4 Switching Device 5 Transmission Device PTO Power Extraction Device H High Speed Position L Low Speed Position N Neutral Position

Claims (1)

[Claims] 1. An operating device 3 of a PTO clutch lever 2 for connecting and disconnecting a main clutch 1 of a power take-off device PTO, a PTO transmission 5 of the power take-out device PTO being switched between a high-speed position H and a low-speed position L to be turned on and off. Switching device 4
PTO gear shift operation device for tractor.