JP2648219B2 - Work vehicle mission case structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to the overall structure of a traveling transmission case in a working vehicle such as an agricultural tractor.

2. Description of the Related Art An agricultural tractor, which is one of working vehicles, includes a traveling transmission case as disclosed in Japanese Patent Application Laid-Open No. Sho 62-120227, and a front case in which a first transmission mechanism is mounted. And a middle case in which the second speed change mechanism is housed, and a rear case in which the third speed change mechanism is housed.

[Problems to be solved by the invention]

As described above, the traveling mission case has a divided structure because a plurality of types of front cases, intermediate cases, and rear cases are prepared, and each case is combined to produce and provide each type of mission case. So
This is useful for convenience in changing the specifications.

However, in the conventional structure, the first transmission mechanism in the front case, the second transmission mechanism in the intermediate case,
At the time of assembling and disassembling with the third speed change mechanism in the rear case, each case is provided with a wall portion for supporting the shaft of the speed change mechanism installed therein, and assembled in order from the front side or the rear side case. The work procedure for assembling and disassembling has been determined so that the assembly and disassembly should be performed in the opposite manner. For this reason, during assembly and disassembly, it is necessary to assemble and disassemble the transmission mechanism in the front case or the rear case while supporting the transmission mechanism in the intermediate case in a cantilevered state. There was a problem that it was difficult.

The present invention is intended to improve the productivity of various types of mission cases, and to assemble the split type mission case when the mission case of the work vehicle is divided.
The purpose is to facilitate disassembly.

[Means for solving the problem]

In order to achieve the above object, the technical means of the present invention provides a transmission case structure for a work vehicle, in which a traveling transmission case is provided with a first transmission mechanism and an opening formed on the rear surface side. Front case and the third
A rear case in which a transmission mechanism is provided and an opening is formed on the front side thereof; and a middle case in which a second transmission mechanism is provided, which is located between the front case and the rear case. The front case is configured such that a bearing case cover for supporting a rear side of the first transmission mechanism is detachably provided at an opening on the rear surface side from the intermediate case side, and the rear case includes: A bearing case cover for supporting the front side of the third transmission mechanism is detachably provided on the front side opening from the intermediate case side, and a second transmission mechanism in the intermediate case is provided. And the first transmission mechanism in the front case or the third transmission mechanism in the rear case are located inside the intermediate case and at a position closer to the bearing case cover than the center of the intermediate case. Mutual transmission It is that the shaft section is connected.

(Operation)

The operation of the above configuration is as follows.

That is, when assembling the front case and the rear case, with the case cover removed, insert the gears and shafts of the transmission mechanism to be installed from the opening of the case cover into the case, and finally attach the case cover. The end of the internally mounted transmission mechanism may be pivotally supported, so that the front case and the rear case can be easily assembled.

When the case cover is attached, the front case and the rear case are formed into a single unit for easy handling, and the case cover is attached, so that the lubricating oil in the case may spill out during the operation. Few.

In this state, the entire transmission assembly of the transmission mechanism provided in the intermediate case is connected to the transmission shaft portions of the front and rear transmission mechanisms that are protruded from the case covers.

 The disassembly is performed in the reverse order.

〔The invention's effect〕

As described above, the transmission case has a divided structure of a front case with an open rear portion, a rear case with an open front portion, and an intermediate case therebetween, and is detachable from the intermediate case side. By providing a case cover, the case cover also serves as a support part for each transmission mechanism in the front case and the rear case, so that various cases can be provided by combining each case, and specifications can be changed. In addition to the advantages of the conventional structure that the convenience in performing the operation can be achieved, the connection and disassembly of the transmission mechanisms in each case, the assembly and handling of each case with disassembly become easy, and the lubricating oil is Spills were less likely to occur, and productivity was improved.

〔Example〕

 Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a transmission case (1) of an agricultural tractor, which is one of the working vehicles. This transmission case (1) has a front case (2) having an opening formed on the rear surface side.
, A rear case (4) having an opening formed on the front side, and an intermediate case (3) located between the front case (2) and the rear case (4). Structure.

Inside the front case (2), a dry single-plate clutch (5), a main transmission mechanism (6) (corresponding to a first transmission mechanism), which is a constant mesh type that shifts the traveling system to four speeds, a constant mesh type And a PTO speed change mechanism (7) for shifting the PTO system to three forward rotations and one reverse rotation. The front surface of the front case (2) is provided with a removable case cover (2a) for bearings. With this, when assembling the front case (2), the case cover (2
a) is opened, each shaft, gears and the like are inserted from the opening on the case cover (2a) side, and finally the case cover (2a) is attached.

The intermediate case (3) includes a constant mesh type forward / reverse switching mechanism (8) (corresponding to a second transmission mechanism) that switches the power from the main transmission mechanism (6) of the front case (2) in the forward and reverse directions, and a PTO. A transmission shaft (9) for transmitting power from the speed change mechanism (7) is provided therein.

In the rear case (4), a constant mesh type first auxiliary transmission mechanism (10) (corresponding to a third transmission mechanism) for shifting the power from the forward / reverse switching mechanism (8) of the intermediate case (3) to two levels of high and low. ) And a constant mesh type second auxiliary transmission mechanism (11) (corresponding to a third transmission mechanism), a rear wheel differential mechanism (12), and a power from a transmission shaft (9) of an intermediate case (3). A transmission shaft (13) for transmitting the drive shaft (not shown) is provided.

The rear case (4) is provided with a removable bearing case cover (4a) on the front surface. Thus, when assembling the rear case (4), the case cover (4a) is opened, and each shaft and gears are inserted from the opening on the case cover (4a) side.
a) is attached.

The shift operation structure of the first auxiliary transmission mechanism (10) in the rear case (4) will be described. As shown in FIGS. 2, 3, and 4, a shift rod (19) is fixed to the rear case (4), and a boss (20) containing a detent mechanism (20a) slides on the shift rod (19). Mounted freely. A bifurcated shift fork (21) is bent and extended from the boss (20) into an L-shape, and is operated by an operating arm (22) provided in the rear case (4). 20) and the shift fork (21) are slid.

(Another embodiment)

FIG. 5 shows a model of FIG. 1 in which a slightly different type of transmission mechanism is provided in the same front case (2) and rear case (4), and the intermediate case (3) is replaced with another intermediate case (14). Is converted to

Next, the mission case (1) shown in FIG. 5 will be described. Front case (2) of this mission case (1)
Inside is a dry single-plate clutch (5), a main transmission mechanism (15) (equivalent to the first transmission mechanism) that shifts the running system to four speeds using a synchromesh type, and a PTO with a constant mesh type
PTO transmission mechanism (7) that shifts the system to one step in three forward and reverse rotations
Is decorated.

The front surface of the front case (2) is provided with a removable case cover (2a) for bearings. Thereby, when assembling the front case (2), the case cover (2a) is opened, and each shaft and gears are inserted from the opening on the case cover (2a) side.
a) is attached.

The intermediate case (14) includes a synchromesh type forward / reverse switching mechanism (16) (corresponding to a second transmission mechanism) for switching the power from the main transmission mechanism (15) of the front case (2) in the forward and reverse directions, and a PT.
A transmission shaft (9) for transmitting power from the O transmission mechanism (7) and a hydraulic clutch (17) for a traveling system are provided.

In the rear case (4), a synchromesh type first auxiliary transmission mechanism (18) (corresponding to a third transmission mechanism) that shifts the power from the forward / reverse switching mechanism (16) of the intermediate case (14) to two levels of high and low. , And a constant mesh type second auxiliary transmission mechanism (11) (corresponding to a third transmission mechanism), a rear wheel differential mechanism (12),
A transmission shaft (13) for transmitting power from the transmission shaft (9) of the intermediate case (3) to a working device (not shown) is provided. The main transmission mechanism (15) and the forward / reverse switching mechanism are operated by a hydraulic cylinder (not shown) provided in the intermediate case (14) in accordance with the on / off operation of the hydraulic clutch (17). (16) and shifting the first auxiliary transmission mechanism (18).

In FIG. 5, the structure of the shift fork (21) shown in FIGS. 2, 3, and 4 is used for the first subtransmission mechanism (18). In this case, the boss (20) is fixed to the shift rod (19), and the shift rod (19) is slid in the axial direction by a hydraulic cylinder (not shown) provided in the intermediate case (14). The structure used is as follows.

In the claims, reference numerals are provided for convenience of comparison with the drawings, but the present invention is not limited to the structure shown in the attached drawings.

[Brief description of the drawings]

The drawings show an embodiment of a mission case structure of a work vehicle according to the present invention, and FIG. 1 is a side view of the entire mission case.
FIG. 2 is a rear view of the shift fork for the first sub-transmission mechanism in the transmission case of FIG. 1, FIG. 3 is a side view of the shift fork for the first sub-transmission mechanism in the transmission case of FIG. The figure is a plan view of a shift fork for the first auxiliary transmission mechanism in the transmission case of FIG.
The figure is a side view of the entire mission case in another embodiment. (1) ... mission case, (2) ... front case,
(2a) ... Case cover of front case, (3), (14)
... Middle case, (4) Rear case, (4a) Rear case cover, (6), (15) First transmission mechanism, (8), (16) Second transmission Mechanism, (10), (1
1), (18): Third transmission mechanism.

Claims (1)

(57) [Claims] 1. A traveling transmission case (1) is provided with a first transmission case (1).
A front case (2) having transmission mechanisms (6) and (15) therein and having an opening formed on the rear surface side; a third transmission mechanism (10);
(11) A rear case (4) in which an opening is formed on the front side of a housing (18), and a second case located between the front case (2) and the rear case (4). Transmission mechanism (8),
(16) is combined with the intermediate cases (3) and (14) that house the interior (16), and the front case (2) is provided with the first transmission mechanism (6), ( 15) Replace the bearing case cover (2a) for supporting the rear side with the intermediate cases (3) and (1).
The rear case (4) supports the front side of the third transmission mechanism (10), (11), (18) in the opening on the front side. A bearing case cover (4a) is provided so as to be detachable from the intermediate cases (3) and (14), and the second transmission mechanism (8) in the intermediate cases (3) and (14). ), (16) and the first transmission mechanism (6), (15) in the front case (2) or the third transmission mechanism (10), (11), (18) in the rear case (4). Are located inside the intermediate cases (3) and (14) and closer to the bearing case covers (2a) and (4a) than the center of the intermediate cases (3) and (14). The transmission case structure of the work vehicle where the transmission shafts are connected to each other.