JPS6285724A - Front wheel speed change operating structure for agricultural tractor - Google Patents

Abstract

PURPOSE:To omit hydraulic system paths, partially thus to simplify the structure by constructing a clutch in standard drive system of a front wheel speed change unit into gearing type while a clutch in speed increment drive system into friction type and functioning both clutches in contrary. CONSTITUTION:In a power transmission system for an agricultural tractor, the power from an engine is speed changed by means of main and sub- transmissions in a transmission case 6 and transmitted to the rear wheel while power branched from the gears 12a, 12b in the sub-transmission 12 is speed changed by means of a front wheel transmitting section 14 in a front wheel transmission 10 and transmitted from the front wheel output shaft 15 to the front wheel. Here, a hydraulic frictional clutch 17 is arranged between the front wheel output shaft 15 and an output ring member 17a idly fitted to said shaft 15. While a gearing clutch 19 is arranged between a drive gear 13 fitted idly over the front wheel output shaft 15 gearing with the gear 12a in the sub- transmission 12 and a shift member 18 fitted idly to the rear end of a piston 17b of the frictional clutch 17.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a rear wheel portion i in a transversely freely movable front wheel transmission system
1] Front wheels of an agricultural tractor equipped with a clutch-type front wheel transmission that switches between a standard drive state in which transmission is performed at a drive speed approximately equal to the rear wheel drive speed, and an accelerated drive state in which power is transmitted at a drive speed greater than the rear wheel drive speed. It relates to a speed change operation structure.

[Conventional technology]

A clutch-type structure for switching the front wheels of a crotch tractor between the standard drive state and the speed-up drive state is disclosed, for example, in Japanese Utility Model Application No. 102133/1983. It is composed of a permanent engagement type gear mechanism and two hydraulic friction clutches, and the thread path of the engine power transmitted through the permanent engagement type gear mechanism is changed by the on/off operation of this M friction clutch. This mechanism had the following implications.

[Problems to be Solved by the Invention] In agricultural tractors, shifting the front wheels to the gear-increasing state is not recommended when changing direction with a small turning radius at the edge of a ridge, or when turning suddenly to avoid danger. However, in such cases, it is often necessary to perform the speed change operation described in 111 quickly, so a 6-speed transmission mechanism using a hydraulic friction clutch that can perform the speed change operation in 7 actions is suitable for this purpose. However, friction clutches are generally expensive and tend to have a complicated overall structure.

On the other hand, the front wheels are shifted to the original state during normal work or when driving on the road, but in such cases, the general VC shift operation must be performed quickly.
The need for a friction clutch is lower than that in the speed-up drive state, or perhaps because of the structure of the conventional structure mentioned above, a hydraulic type is not required for the speed change operation of both the standard and speed-up I8I dynamic state spoons. J11 friction clutch is used, which increases the production cost and complicates the device? I was invited.

Here, in the front wheel transmission according to 1fJ, which is an object of the present invention,
The purpose of this invention is to reduce the cost and simplify the structure of the N11-wheel transmission without causing a decrease in V & performance.

[Means for solving intervening points]

The feature of the present invention is that, in the front wheel speed change operation structure of an agricultural tractor, the clutch of the standard drive system of the wheel speed change device is configured as a biting type clutch, and the clutch of the speed increasing drive system is configured as a hydraulic friction clutch. and mechanically operates the shift member of the mJEW'Z combination clutch in conjunction with the movement of the piston member in the friction clutch, so that both clutches engage and disengage in a contradictory manner,
Further, a spring is interposed between the piston member and the shift member so that the shift member is operated to engage the clutch elastically, and its functions and effects are as follows.

[For production]

As mentioned above, by replacing the conventional two hydraulic friction clutches with seven mechanical clutches, which are cheaper than hydraulic clutches, some of the hydraulic lines can be omitted and the structure simplified. At the same time, costs can be reduced. In addition, by linking the piston member of the friction clutch with the shift member that controls the on/off operation of the dog clutch, important operations of both clutches can be performed only by operating the piston of the friction clutch, improving the structure of the shift operation system. Natsuyuki will be abbreviated as frpJ.

[Effects of the Invention] As explained above, the present invention makes it possible to reduce the cost and simplify the structure of the front wheel transmission in an agricultural tractor. In addition, the speed change operation in both the standard and increased speed states is configured in a manner that the piston member of the specific friction clutch, which is a common member for both the operation of the bite type clutch, ITJ, and friction clutch, is operated in a reverse manner by +7"J. Therefore, +!IJ
It is unlikely that both clutches will be engaged at the same time, and this makes it possible to prevent damage caused by Vζ. Furthermore, since the piston member described in [1r] and the shift member of the bite-type clutch are elastically linked by a spring, when the bite-type clutch is operated to the engaging side, even if the phase of the bite of the bite-type clutch does not match, When the clutch engagement operation is absorbed by the spring and the phase of the occlusal phase matches, the biasing force of the spring adjusts and the clutch is engaged, so that the clutch engagement operation of the occlusal type clutch can be performed smoothly. became.

Embodiment] Hereinafter, an agricultural tractor which is an embodiment of the present invention will be described based on the drawings.

As shown in Figure 4, a pair of left and right steering type front wheels fi+
The engine (4), main clutch (5), mission case (6), and control unit (7) are mounted on the fuselage frame (3), which supports the +11 and rear wheels (2) and +21 ft in a freely movable manner. A lift arm (8) that can be swiveled up and down to connect various work equipment such as a rotary tiller to the rear so that it can be raised and lowered, and a PTO that transmits power to the work equipment.
A shaft (9) is provided to constitute a four-body type agricultural tractor.

Next, the power transmission system of the agricultural tractor and the front Nl transmission (
In detail, as shown in Figures 3 and 4, the power from the engine (4) is mainly from the launch (5),
Mission case (6) via the assist transmission shaft (++)'
A main transmission 11 (not shown) and a sub-transmission (12)
1 is fully transmitted and the gear is changed, driving the rear wheels +2+ (2), and the sub-transmission gear ``(12a)+(
The power branched from 12b) is sent to the front wheel transmission transmission part (14) in the front wheel transmission bag @ (10), where the gear is changed, and then sent to the front wheel differential mechanism (1a) via the front export power shaft (+5).
It is configured to drive the front wheels +1+ (1+).

To explain in detail the front wheel transmission section, the first
．． As shown in Figure 2.3, the sub-transmission l! (12) The first passive gear 0 (g) that meshes with the gear (12a) is loosely fitted into the front export force shaft (+5) K, and the second passive gear α4 that meshes with the gear (12b) is fitted with the front export force It is fixed to the output wheel body (17a) loosely fitted to the shaft (161), and a hydraulic friction clutch αη is provided between the output wheel body (17a) and the front export force shaft 06). Also, the piston (1) of the friction clutch (17)
7b) The rear end is moved in the axial direction of the front export force shaft (15) by the engagement action of the piston (17b) and the urging force of the spring (a)), and has a spline structure to form the front export force shaft a5). - The movable shift 111 (material ■ is fully fitted on the outside, and the claw of this shift member (18)! ((18a) is engaged with the engaging part (13a) of the upper first receiver ωj gear ■) An engagement type clutch (+9) is configured between the first receiving gear (13) and the shift member (18) so as to be engaged with each other.

In Fig. 1, pressure oil is supplied from a pump (not shown) to the friction clutch αη via the oil passage (15a), and the piston
is brought forward to put the friction clutch (17) into the engaged state, and the shift member a~ that is engaged and interlocked with the piston (17b) is separated from the engagement part (13a) of the first passive gear (+3) and engaged. This shows a state in which the clutch (+9) is in a disengaged state. This state is a state in which the front wheels (1)+(1) have been completely shifted to an increased speed drive state.

Next, as shown in FIG. 2, when the pressure oil supply to the friction clutch aη is stopped, the piston (17b) moves back due to the biasing force of the spring (17c), and the friction clutch aη becomes disengaged. ) due to the biasing force of the shift member (18
+ moves to the first receiving gear O■ side, and the claw of the shift member α→! 15 (18a) is the retaining part (1
3a), and the engaging type clutch θ9) is in the engaged state. In this state, the front wheels [1] and +11 are being shifted to the standard drive state.

As described above, lrl M [11·(1) is shifted to the standard and increased speed states.

In the above embodiment, as shown in FIGS. 1 and 2, the spring (, +0) that biases the shift member 0 toward the engaging clutch (19) is connected to the friction clutch. The output wheel of αη (17
a), but the piston (17b) may be provided with a support portion to support the springs.

[Brief explanation of drawings]

The drawings show an embodiment of the front wheel gear shift operation structure for an agricultural tractor according to the present invention, and FIG.
The figure is a longitudinal cross-sectional side view showing the front wheel transmission being shifted to the standard U front state, Figure 3 is a plan view of the vicinity of the sub-transmission and 1 If T-wheel transmission, and Figure 4 is the entire agricultural tractor. FIG. +1+...Front wheel, ILII...W [Wheel transmission, Q71...Friction clutch, (17b)...
... Piston member, Q8) ... Shift member, (1!4i ... Articulating clutch, 伽) ...
...Battle agent Patent attorney Shunu Kitamura 1 Zutomi 2 Iris 4 Sono

Claims (1)

[Claims] The transmission system to the steerable front wheels (1), (1) has a standard drive state in which power is transmitted at a drive speed approximately equal to the rear wheel drive speed, and an increased speed drive state in which power is transmitted at a drive speed greater than the rear wheel drive speed. A front wheel shift operation structure for an agricultural tractor equipped with a clutch-type front wheel transmission (10) that switches to a clutch type front wheel transmission (10), wherein a clutch (19) of a standard drive system of the front wheel transmission (10) is configured as an engagement type clutch (19). At the same time, the clutch (17) of the speed increasing drive system is configured as a hydraulic friction clutch (17), and the above-mentioned occlusion is mechanically interlocked with the movement of the piston member (17b) in this friction clutch (17). By operating a shift member (18) of a type clutch (19), both clutches (17) and (19) are configured to engage and disengage in a reverse manner, and the shift member (18) is elastically engaged and engaged. The piston member (1
A front wheel shift operation structure for an agricultural tractor in which a spring (20) is interposed between the shift member (18) and the shift member (18).