JPS6288621A - Agricultural tractor travel transmission structure - Google Patents

Abstract

PURPOSE:To simplify the transmission construction by forming a standard driving system with a man-power type claw clutch and forming the operating valve mechanism of a hydraulic friction clutch with the shift member of said claw clutch, in an agricultural tractor with a clutch type front wheel transmission. CONSTITUTION:In an accelerating drive condition, the claw 18a of a shift member 18 is apart from the engaging part 13a of a first receiving gear 13 disengaging a claw clutch 19, while a friction clutch 17 is engaged. In this condition, the shift member 18 is moved to the first receiving gear 13 side. Thereby, a pressure oil feeding passage is cut off by the inner surface of the shift member 18, and pressure oil in the friction clutch 17 is discharged through an oil passage 15a and an oil passage 18c of the shift member 18. accordingly, a piston 17b is moved back by means of a spring 17c, the friction clutch 17 is disengaged and, then, the claw 18a is engaged with the receiving gear 13 to engage the clutch 19, shifting to a standard drive condition. Thereby, a traveling driving mechanism can be simplified.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a transmission system for steerable front wheels with a standard drive state in which power is transmitted at a drive speed approximately equal to the rear wheel drive speed, and a rear wheel #
A! 1] The present invention relates to a running transmission structure for an agricultural tractor equipped with a clutch-type front wheel transmission that switches to an accelerated drive state in which transmission is performed at a drive speed higher than the drive speed.

[Prior art] A clutch type structure for switching the front wheels of an agricultural tractor between the standard drive state and the speed-up drive state as described above is as follows.
For example, as disclosed in Japanese Utility Model Application Publication No. 60-102133, this is composed of a permanent bite type gear mechanism and two hydraulic friction clutches, and the critical operation of this friction clutch causes the permanent bite type to This is a mechanism that changes the speed by changing the engine power system FIlr transmitted within the gear mechanism, but this has the following problems.

[Problem that the invention seeks to solve]

In agricultural tractors, shifting the front wheels to an increased speed drive state is necessary when changing direction with a small turning radius at the edge of a ridge, or when making a sharp turn to avoid an immediate danger. In general, there are many cases in which the gear shifting operation must be performed quickly, so a transmission mechanism using a hydraulic friction clutch that allows the gear shifting operation to be performed by action is suitable for this purpose, but friction clutches are generally expensive and require a large structure of the entire transmission device. tends to be complex.

On the other hand, the front wheels are shifted to the standard drive state during normal work or when driving on the road, but in such cases there are generally few opportunities to shift gears quickly, and the need for a friction clutch is reduced to increase speed. Although this is lower than in the drive state, the conventional structure described above uses a hydraulic friction clutch for speed change operations in both the standard and increased drive states, which increases manufacturing costs and equipment. This led to complications.

Here, the object of the present invention is 1. In the front wheel transmission,
The object of the present invention is to reduce the cost and simplify the structure of a front wheel transmission without deteriorating its functionality.

[Means for solving problems]

The feature of the present invention is that in the traveling transmission structure of the agricultural tractor described above, the clutch of the standard drive system of the front wheel transmission is configured as a manually operated articulating clutch, and the clutch of the speed increasing drive system is configured as a hydraulic friction clutch. configured to, and
The shift member of the collimating clutch is configured as a part of a valve mechanism that controls the operation of the friction clutch, so that both clutches are configured to operate on and off in a contradictory manner,
Its action and effects are as follows.

[For production]

As mentioned above, by replacing the conventional two hydraulic friction clutches with mechanical bite-type clutches, which are cheaper than hydraulic ones, some hydraulic lines can be omitted, simplifying the structure. It is also possible to reduce costs. Furthermore, by making the shift member of the biting clutch share the valve function of supplying operating pressure oil to the hydraulic friction clutch of the speed-increasing drive system, the pressure oil supply line can be simplified, and The structure can be further simplified by making it possible to perform speed change operations in both the standard and accelerated drive states using seven of the shift members. [Effects of the Invention] As explained above, the present invention enables This makes it possible to reduce the cost and simplify the structure of front wheel transmissions in tractors. In addition, the gear shifting operation in both the standard and increased speed states is performed in a contradictory way by the shift member, which is a common part between the mechanical engagement clutch and the hydraulic friction clutch operation.
Since it is configured to be operated by J, both the clutches are not engaged at the same time, and the structure is such that damage to the device due to this can be prevented.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS An agricultural tractor that is an embodiment of the present invention will be described below based on the drawings.

As shown in Figure 4, a pair of left and right steering type front wheels fil
Airframe frame supporting ifil and rear 11ii1 (21, (2)) [31VC engine (4),
Equipped with a main clutch (6), a mission case (6), and a vertical rod part (7), it can be driven up and down to swing freely to connect various work devices such as a rotary tiller WIt to the rear of the machine. A four-wheel drive agricultural tractor is constructed by providing a tow arm (8) and a PTO shaft (9) for transmitting power to the working device.

Next, the power transmission system and front wheel transmission + l of the agricultural tractor.
To explain in detail about ot, as shown in Fig. 3 and Fig. 9114, the power is mainly from the engine (4). ',/chil
The power is transmitted to the main transmission (not shown) and the auxiliary transmission 021 in the mission case (6) through the power transmission shaft (11), and the gears are changed to the rear wheels (2) and +2.
1 and the gear (12a) of the sub-transmission device α.
・The power branched from #-i (12b) is sent to the front wheel transmission transmission unit (I4) in the front wheel transmission system, is shifted, and is sent to the front wheel differential mechanism (1a) via the front export power shaft (1). The vehicle is configured to drive the front wheels +11 Ifl).

To explain the front wheel transmission transmission section (I4) in detail, as shown in Fig. 1.2.3, the front wheel transmission transmission unit (I4) has a first passive gear (1) and a second A second passive gear α is loosely fitted to the front export force shaft (15), and a hydraulic type A friction clutch (171) is provided. Also, a spline structure is provided between the first passive gear 0 and the friction clutch Oη, so that it can freely rotate integrally with the front export force shaft (15). (15
The shift member H that is movable in the axial direction of
5), and the shift member θ~ is moved in the axial direction by engaging the claw portion (18a) of the barrel with the retaining portion (13a) of the first passive gear rJ4. An engagement type clutch α91 is configured between the first passive gear 0 and the shift member U so as to be engaged.

Fig. 1 shows the shift member 08) in an infant state on the friction clutch (I7) side, and the claw portion (1) of the shift member Q@.
8a) is a state in which the first passive gear is separated from the first passive gear (13a), the biting type clutch (191 is in the disengaged state, the friction clutch αη is in the engaged state, and the speed is being changed to the speed-up drive state). In this case, the pressure oil supply for the piston ('17b) inside the friction clutch is a pump (not shown).
The oil is supplied through the oil passage (15a) within the front wheel output shaft and the α-uniform α-uniform oil passage (18b).

Next, as shown in Fig. 2, when the shift member α~ is moved toward the first passive gear H side, the pressure oil supply from the pump (not shown) is cut off by the inner surface of the shift member α (towards). ,
The pressure oil in the friction clutch (lη) is discharged to the outside of the clutch through the oil passage (15a) and the oil passage (18c) in the shift member, and the piston (17b) is moved back by the biasing force of the spring (17c). The friction clutch (17) is in the disengaged state. On the other hand, the biting clutch (17) of the first passive gear α
20), the shift member (claw portion (18a) of 181)
is engaged with the engaging portion (13a) of the first passive gear, and the engagement type clutch (l) is engaged, resulting in a standard drive state.

In the manner described above, the front wheels fl) and +1) are shifted between the standard and increased speed states.

Oil passage (18b) l (
18c) is collectively referred to as a valve mechanism that controls the operation of the friction clutch Qη.

[Brief explanation of drawings]

Is the drawing an example of the traveling transmission frame for an agricultural tractor according to the present invention? 1 is a vertical cross-sectional side view showing a state in which the front wheel transmission is being shifted to the speed increasing section 1 side, and FIG. 2 is a longitudinal cross-sectional view showing a state in which the front wheel transmission is being shifted to the standard drive side. FIG. 3 is a partially cutaway plan view of the vicinity of the auxiliary transmission and front wheel transmission, and an overall side view of the fourth factor #-i agricultural tractor. +l)...Front wheel, (lO)...Front wheel transmission, aη...Friction clutch, bet...
・Shift member, (191... bite type clutch,
End...Valve mechanism. Agent Patent Attorney Kitamura Shuko 4 ■

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. This is a traveling transmission 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 a manually operated engagement type clutch. At the same time, the clutch (17) of the speed increasing drive system is configured as a hydraulic friction clutch,
and a shift member (18) of the biting clutch (19).
) is a valve mechanism (
20), and both clutches (17) and (19
) is a traveling transmission structure for an agricultural tractor that is configured to operate on and off in a contradictory manner.