JPS6340028Y2 - - Google Patents

Description

[Detailed description of the invention] (a) Field of industrial application The present invention relates to a speed change operation device for plowing and reversing agricultural tractors.

(b) Prior Art Conventionally, the hydraulic control lever that operates the hydraulic lift arm located at the rear of an agricultural tractor and the main shift lever that controls forward and reverse movement were designed to operate independently of each other.

For this reason, when plowing while moving the agricultural tractor forward, it was necessary to operate the main gear shift lever to the forward or reverse position, respectively, and to operate the lift arm control lever.

This is because agricultural tractors are mostly operated in forward motion, and rarely in reverse.

In recent years, technology has become available that incorporates safety measures such as raising the work equipment when reversing.

(c) Problems that the invention aims to solve If the structure was such that the work equipment would automatically rise when the agricultural tractor goes backwards, it would be possible to raise the work equipment that is stuck in the soil when going backwards. By doing so, it is possible to prevent damage to the work equipment that may occur due to the operator reversing without noticing.

However, there are cases where the implement is moved backwards to plow the land, such as when breaking a ridge, or when a implement such as a Bucket or Hehawk is attached to the rear of an agricultural tractor and the implement is moved backwards with the implement lowered.

When using a work machine for this purpose, if the lift arm is raised when reversing, the work cannot be done in reverse, and it has both advantages and disadvantages.

In order to make the rotary tilling device capable of backward tilling, the present invention changes the shift operating positions of the main shift lever to reverse gear R1, reverse tiller gear R2 and 2, without eliminating these advantages and in order to cover the drawbacks. The lift arm rises in reverse gear R1,
In the backward tilling stage R2, the lift arm can be lowered.

(d) Means for solving the problem The purpose of the present invention is as described above. Next, the configuration for achieving the purpose will be explained.

In a gear shift operation device for an agricultural tractor, the main gear shift lever 17 is configured to be able to change speeds appropriately within a shift pattern configured in an H shape, and a reverse drive position is disposed opposite the first gear position. 48 to the upward side so that the lift arm 20 can be raised, and at the same time, a switch 46 is provided that protrudes to switch the lift arm 20 to the upward direction. It has a reverse position.

(E) Embodiment The purpose of the present invention is as described above, and next, the structure of the embodiment shown in the attached drawings will be explained.

Figure 1 is an overall side view of an agricultural tractor equipped with a work implement, Figure 2 is a sectional view of the transmission of the agricultural tractor, Figure 3 is a perspective view of the gear shift operation section, and Figure 4 is a gear shift lever with reverse tillage. A plan view of the guide, FIG. 5 is a plan view of a conventional gear shift lever guide,
FIG. 6 is a hydraulic circuit diagram.

As shown in FIG. 1, an agricultural tractor has an engine 2 mounted inside a bonnet 1, and a front axle bracket 3 protruding forward from the engine 2. A front differential case is supported by the front axle bracket 3, and a front wheel 5 is supported by a front axle that projects laterally from the front differential case.

A clutch housing 7 is fixed to the rear surface of the engine 2, and a transmission case 8 is fixed to the rear surface of the clutch housing 7. A rear axle housing protrudes from the side surface of the transmission case 8 or the rear axle case, and the rear wheel is supported by the rear axle housing.

PTO shaft 11 from the rear of the transmission case 8.
protrudes and connects the universal joint 12 to the work machine.
Power is transmitted through the Mission case 8
Control levers protrude from the left and right sides. On the left side
A PTO shift lever 14, a front clutch lever 15, a sub-shift/creep shift lever 16, and a hydraulic lift operation lever 6 are provided on the right side, and a main shift lever 17 is protruded from the top surface.

PTO shift lever 14 on the side, front clutch lever 15, sub-shift/creep shift lever 1
6, the fender 18 surfaces on both sides of the seat 67 are also used as speed change guide plates. 19 is a hydraulic case, 20
is the lift arm.

Next, the power transmission path will be explained with reference to FIG.

The driving force of the engine 2 is transmitted to an input shaft 21 protruding from a transmission case 8 while being connected and disconnected by a main clutch device within a clutch housing 7. The input shaft 2 is located at the rear on the same axis as the input shaft 21.
A main shaft 22 whose front end is supported by a bearing is supported in the rear end surface hole of 1. Shafts are arranged at respective positions of a pentagon with the input shaft 21 and the main shaft 22 as vertices.

A pinion shaft 24 has a pinion 23 engraved on the right side facing rearward in the forward direction, and a front power take-off shaft 25 and a creep shaft 26 are disposed coaxially below the pinion shaft 24 .

Further, a counter shaft 27 and a PTO transmission shaft 28 are arranged on the left side when facing the direction of travel.

The power input from the input shaft 21 is transmitted to the fixed gear 2
9 to the counter shaft 27 and further to the fixed gear 2
9 transmits power to the PTO transmission shaft 28 via a fixed gear 30 on the PTO transmission shaft 28.

Therefore, the main shift lever 17 described above is used to shift the forward speed to 3.
It is possible to change gears to 1 gear, reverse, and 1 gear to plow and reverse.

The main gear lever 17 has two shifter forks 3
2, 33 are configured to selectively slide on the shifter fork shaft.

Then, the shifter fork 32 causes the sliding gear 36 of the main shaft 22 to slide back and forth to change gears between reverse and one forward gear, and the shifter fork 33 similarly causes the double sliding gears 37 and 38 of the main shaft 22 to slide back and forth. 2 forward speeds and 3 reverse speeds are achieved.

One forward stage is obtained by the sliding gear 36 meshing with the fixed gear 42 on the counter shaft 27.

The second forward stage is one of two sliding gears 37 and 38.
is obtained by meshing with a part of the fixed gear 30.

The third forward stage is the other 38 of the double sliding gears 37 and 38.
is obtained by meshing with a part of the fixed gear 41 on the counter shaft 27.

In the reverse gear, the rotation of the counter shaft 27 is constantly meshed with the double reverse loose fit gears 43 and 44 on the pinion shaft 24 by the fixed gear 30, and the sliding gear 36 is constantly engaged with the double reverse loose fit gears 43 and 44 on the pinion shaft 24. The other 43 of 44
By engaging with the gear, it becomes a reverse gear.

In other words, to shift to reverse gear, the main shift lever 17 slides the shifter fork 32, and the main shaft 2
This is made possible by sliding the sliding gear 36 on the top of the screen.

However, since the present invention also requires a plowing reverse gear, the engagement groove 32a at the upper end of the shifter fork 32, which is engaged with the lower protrusion of the main gear shift lever 17, is made smaller than the conventional one, as shown in FIG. It extends further, and the range of operating positions of the main shift lever 17 in the reverse gear of the shifter fork 32 is made longer in the left and right directions.

For this reason, in addition to the conventional reverse gear R1 shown in FIG. 5, the reverse gear position of the main shift lever 17 can be provided with one more reverse plow gear R2 as shown in FIG. However, there may be two or more reverse gears.

The operating position of the main gear shift lever 17 is different between the reverse gear R1 and the reverse tiller gear R2, but the shifter fork 3
The operation of the second gear is the same, and therefore the gear change contents are the same.

A switch 46 is provided at the reverse gear R1 position so that when the main gear shift lever 17 is operated to the reverse gear R1 position, the lift arm 20 is raised.
The sliding plate 34 is moved by a servo motor 47 that is linked to
slides.

An oblong hole 34a is provided in this sliding plate 34, and inside this oblong hole 34a there is provided a tip of a feedback rod 49 which is an operating part of a hydraulic directional control valve 48 of a hydraulic lift cylinder 19. stands out. Therefore, when the servo motor 47 is driven, the sliding plate 34 slides, operating the feedback rod 49 and lifting the lift arm 20.

Then, when the main shift lever 17 is operated to the reverse plow stage R2, which is another reverse shift position, the main shift lever 17 does not touch the switch 46, and only the reverse shift can be performed.

In this way, it was possible to set the position of the backward tilling gear R2, but the feed back lock 49 operates at this rear tilling gear R2, and the feed back can also be adjusted by operating the lift arm operating lever 6. Since the back rod 49 must be structured to operate, the oblong hole 34 provided in the sliding plate 34 must be
A is made long as a play hole with the feedback rod 49, and the structure is such that the feedback rod 49 is operated by both the lift arm operating lever 6 and the sliding plate 34. It is.

Another method for operating the lift arm 20 is to operate the hydraulic directional control valve 4 using a solenoid or a control lever interlocked with the main shift lever 17.
8, or an independent check valve or hydraulic directional control valve may be provided.

The flow of oil that operates this hydraulic lift cylinder 19 is as shown in FIG. flow in the direction.

Reference numerals 53 and 54 are external extraction holes for pressure oil controlled by the hydraulic directional control valve 48.

This hydraulic directional control valve 48 is configured to change the flow of pressure oil by the above-described operation.

(f) Effects of the invention Since the invention is constructed as described above, it has the following effects.

First, a reverse position is provided opposite the 1st gear position, and a switch is provided that moves the lift arm upward, so in reverse gear R1, which is a normal reverse gear shift, the hydraulic lift is raised as a safety measure. It is now possible to raise the work equipment, eliminating the problem of the operator backing up and destroying the work equipment without realizing that the work equipment is dug into the ground, and causing the operator to operate the equipment unconsciously. However, the work equipment would still rise, so an unexpected accident could have been prevented.

Second, we have created another reverse position close to the reverse position that bypasses the 1st speed/reverse operation area and is unrelated to lifting and lowering the lift arm, making it easier to perform work when reversing, such as when reversing plowing or hoof-oaking. Moreover, in the case of such special work, since the directions are different, the gears must be changed carefully, so there are no mistakes in operation.

Thirdly, the main shift lever has two shift operation positions: reverse gear R1 and reverse tiller gear R2, so it can be used differently depending on the purpose, widening the work range and enabling safer work. It is.

[Brief explanation of the drawing]

Figure 1 is an overall side view of an agricultural tractor equipped with a work implement, Figure 2 is a sectional view of the transmission of the agricultural tractor, Figure 3 is a perspective view of the gear shift operation section, and Figure 4 is a gear shift lever with reverse tillage. A plan view of the guide, FIG. 5 is a plan view of a conventional gear shift lever guide,
FIG. 6 is a hydraulic circuit diagram. A...Rotary tillage device, R1...Reverse gear,
R2...Reverse tilling stage, 17...Main gear shift lever, 2
0...Lift arm.

Claims (1)

[Scope of utility model registration request] In a gear shift operation device for an agricultural tractor, the main gear shift lever 17 is configured to be able to change speeds appropriately within a shift pattern configured in an H shape, and a reverse drive position is disposed opposite the first gear position. A switch 46 for switching the lift arm 20 to the upward side is provided protrudingly to enable the lift arm 20 to rise.In addition, a switch 46 is provided that protrudes to switch the lift arm 20 to the upward direction. A gear shift operating device for an agricultural tractor, characterized by having a reverse position.