JPH0537079Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] This invention relates to the breather structure of a transmission case in agricultural machinery such as a power tiller or a binder. Regarding the breather structure of the combined two-part transmission case.

[Conventional technology]

Conventionally, as shown in FIG. 5, a bolt 18 was screwed into the upper wall 015 of one of the two halves of the transmission case, and the pressure inside the case was released through a hole 18A formed in the bolt 18.

[Problem that the invention attempts to solve]

There was a drawback in that the mist of oil scraped up by the high-speed rotation of the gear immersed in transmission oil was blown out through holes formed in the bolts.

In addition, when providing a breather structure, drilling holes in the case, threading the holes, and
Holes must be drilled for the bolts,
There were inconveniences such as the troublesome manufacturing process and high costs due to the manufacturing effort.

The present invention aims to provide a breather structure that suppresses oil blow-out, reduces costs, and exhibits good breather function by devising the breather structure. .

[Means for solving problems]

The characteristic structure of this invention to achieve the above purpose is as follows:
On the upper side of the transmission case, walls are integrally extended from a pair of left and right cases to form a breather chamber, and the bottom wall of the breather chamber is connected to one side in a direction orthogonal to the stacking direction of the cases. is formed on a sloped bottom wall where one side is high and the other side is low, and further,
Two communication holes are formed on the mating surface of the bottom wall to communicate the interior space of the case with the breather chamber, and two communication holes are formed on the mating surface of the upper wall forming the breather chamber to communicate the breather chamber and the outside of the case. A communicating hole is formed, and each of the communicating holes is integrally molded when the case is molded, and this structure provides the following functions and effects.

[Effect]

Since the breather chamber is formed, the pressure is reduced in the breather chamber and oil blowout is suppressed. Moreover,
The bottom wall of the breather chamber is an inclined surface, and two holes communicating with the case are formed on the inclined surface, so that oil adhering to the inner wall of the breather chamber flows into the case through the lower communicating hole. By dripping the oil into the breather chamber through the higher hole, gas and liquid can be separated well and a good breather function can be achieved. moreover,
The slanted bottom wall of the breather chamber is formed with one side being high and the other being low in the direction perpendicular to the stacking direction of the cases, so that one side is high and the other is low in the stacking direction of the cases. Compared to slanted models, the angle of inclination of the bottom wall of the breather chamber can be set freely without increasing the thickness of the bottom wall of the breather chamber in relation to the direction of mold removal of the case. The liquid can be refluxed smoothly. In addition, since the communication hole leading to the case and the communication hole communicating with the outside air are formed on the mating surfaces of the cases, the communication hole can be formed integrally when the case is molded, eliminating the need for drilling the communication hole. Become.

〔effect〕

The pressure reduction effect of the breather chamber suppresses oil blow-out, thereby preventing contamination of the outer surface of the case due to the blow-out.

In addition, a good breather function can be achieved by setting the shape of the bottom wall of the breather chamber and the number of communicating holes communicating with the inside of the case. Furthermore, the cost of the breather structure can be reduced by eliminating the need for drilling the communicating holes.

〔Example〕

The drawing shows an embodiment of a walk-behind cultivator, in which an engine 1 is mounted on the front part, and left and right axles 2a, 2a protruding from the bottom of a transmission case 2 have wheels 3, which can be replaced with a tiller. A hitch 5 for connecting various attachment working devices such as a rotary tiller and a trailer is provided at the rear of the traveling main body configured by attaching the drive unit 3, and a control handle 4 is provided extending to the rear. The power is transmitted to the left and right wheels 3, 3 via a transmission mechanism within the transmission case 2, thereby forming a walk-behind cultivator as an example of an agricultural machine.

The transmission case 2 consists of a pair of left and right halves, and has flange parts 2a, 2.
A are overlapped and integrally connected. At the upper part of the mission case 2, walls 10 are integrally extended from the left and right cases 2A, 2A, respectively.
10 forms a breather chamber 11.

The bottom wall 12 of the breather chamber 11 is connected to the case 2.
The bottom wall is formed with an inclined bottom wall, one of which is high and the other is low, in a direction perpendicular to the overlapping direction of A and 2A.

Two communication holes 14, 14 are formed in the mating surface of the bottom wall 12 of the breather chamber 11 to communicate the case inner space 13 and the breather chamber 11,
Furthermore, on the mating surface of the upper wall 15 of the breather chamber 11,
A communication hole 16 is formed that communicates the breather chamber 11 with the outside of the case.

The mission case 2 is molded by aluminum die casting, and the communicating holes 14, 14, 16 are integrally molded when the case is molded.

17 is a sealing material interposed between the cases 2A, 2A. Although the present invention has been exemplified with respect to the structure of a transmission case of a tiller, it can also be applied to the structure of a transmission case of a binder or the like.

Further, although reference numerals are written in the claims section of the utility model registration for convenience of comparison with the drawings, the present invention is not limited to the structure of the accompanying drawings by such entry.

[Brief explanation of the drawing]

The drawings show an embodiment of the breather structure of the mission case according to the present invention, FIG. 1 is a longitudinal side view of the main part, FIG. 2 is a longitudinal rear view of the main part, and FIG. 3 is a plan view of the main part. FIG. 4 is a side view showing the entire walk-behind cultivator, and FIG. 5 is a longitudinal cross-sectional rear view of the main parts showing the conventional structure. 2a...Flange portion, 2A...Pair of left and right cases, 2...Mission case, 10...Wall, 11
... Breather chamber, 12 ... Bottom wall, 13 ... Case interior space, 14, 16 ... Communication hole, 15 ... Top wall.

Claims (1)

[Scope of utility model registration request] In two split mission cases in which a pair of left and right cases 2A, 2A are overlapped with their flanges 2a, 2a, on the upper side of the mission case 2, from a pair of left and right cases 2A, 2A, respectively. The walls 10, 10 are integrally extended to form a breather chamber 11, and the bottom wall 12 of the breather chamber is an inclined bottom wall, one of which is high and the other is low in a direction perpendicular to the stacking direction of the cases. Further, two communication holes 14, 14 are formed on the mating surface of the bottom wall 12 to communicate the case inner space 13 and the breather chamber 11, and an upper wall forming the breather chamber 11 is formed. A breathing hole 16 for communicating the breather chamber 11 with the outside of the case is formed on the mating surface of the transmission case 15, and the communication holes 14, 14, 16 are integrally molded when the case is molded. .