JPS6026171Y2 - Breather device for side valve type engine - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a breather device for a crank chamber in a side valve type engine in which a valve chamber is integrally formed with a crankcase.

In this type of side valve type engine, as shown in FIG. 7, a cylinder 72 in which a valve chamber 71 is formed and a crankcase 73 are integrally formed, and the valve chamber 71 and crank chamber 74 are connected to each other through a breather hole. 75 in communication with the crank chamber 7.
4, the conventional breather hole 75 was formed by drilling after die-casting the cylinder 72 and crankcase 73, for example, as shown in the figure.

This not only increases the number of machining steps, but also requires drilling in a diagonally downward direction as indicated by arrow 76, which has the drawback of making the machining work troublesome.

In addition, as another conventional example, as shown in Japanese Utility Model Publication No. 55-56162, a vertical wall portion 78 is formed on the partition wall 77 between the valve chamber 71 and the crank chamber 74 in FIG.
There is a device in which the breather hole 75 can be cast out at the same time as the valve chamber 71 by drilling a nearly horizontal breather hole 75 along the opening direction 79 of the valve chamber 71 in the vertical wall portion 78. Although the number of machining steps does not increase, since the horizontal breather hole 75 is formed in the vertical wall section 78, the vertical length L of the opening edge 71a of the valve chamber 71 is larger than the diameter of the breather hole 75. However, the valve chamber cover 80 becomes larger, resulting in an increase in weight and cost.

This idea was made in order to eliminate the above-mentioned conventional drawbacks, and a breather hole was formed in the partition wall between the valve chamber and the crank chamber so that it could be formed by casting in a direction almost perpendicular to the opening direction of the valve chamber. An object of the present invention is to provide a breather device for a side valve type engine that reduces man-hours and prevents increases in weight and cost.

Embodiments of this invention will be described below with reference to the drawings.

In FIG. 1, a valve chamber 12 in which a valve 11 is set is integrally formed in a crankcase 14 together with a cylinder 13 by die-casting, and the valve chamber 12 and crank chamber 15 communicate with each other through a breather hole 16. has been done.

A breather pipe 19 is provided between the valve chamber cover 17 that closes off the valve chamber 12 and the air cleaner 18, so that the crank chamber 15 is connected to the breather hole 16, the valve chamber 12, , through the breather pipe 19 and the air cleaner 18 to be exposed to the atmosphere.

The valve chamber cover 17 is equipped with a check valve 22 and a shielding plate 23 for brushing off lubricating oil sent from the crank chamber 15 together with the air.

The breather hole 16 is provided in a partition wall 25 that partitions the valve chamber 12 and the crank chamber 15, and as shown in FIG. A recess 27 is formed in the middle of the valve fitting hole 28 and extends in the opening direction 26 (arrow) of the valve chamber 12, and the bottom of the recess 27 is parallel to the opening direction 26. The breather hole 16 is formed in the wall 27a along a direction substantially perpendicular to the opening direction 26.

As a result, the bottom surface 29 of the portion of the partition wall 25 shown in FIG. 3 where the recess 27 is not formed is flush with the opening edge 16a of the breather hole 16 shown in FIG. 4.

This flush configuration is also shown in FIG.

Therefore, as shown in FIG. 2, the bottom surface 29 of the partition wall 25 in FIG. 5 is molded using the first mold 31 for molding the crank chamber 15. When forming the recess 27 with the mold 32, the breather hole 16 is formed by the arrow 3.
3.It is formed simultaneously with casting in the 34 direction.

In the above embodiment, one breather hole 16 was provided, but as shown in FIG. 6, two recesses 27 are provided, and each recess 27 has one breather hole 16 in total. You can.

As mentioned above, according to this invention, the breather hole 16 shown in Fig. 2 is formed at the same time as the casting, so there is no need for post-processing as in the conventional example shown in Fig. 7, and the number of processing steps is reduced. ,
Manufacturing becomes easier and cheaper.

Further, since the breather hole 16 in FIG. 2 is along a direction substantially perpendicular to the opening direction 26 of the valve chamber 12, the vertical length L of the opening edge 71a of the valve chamber 71 is Since the valve chamber cover 17 shown in FIG. 1 is not enlarged, an increase in weight and cost is prevented.

In addition, since a recess 27 is formed in the partition wall 25 shown in FIG. It also has the advantage that it can be smoothly returned from the breather hole 16 to the crank chamber 15 without being trapped in the valve chamber 12.

[Brief explanation of the drawing]

Fig. 1 is a vertical sectional view showing an embodiment of this invention, Fig. 2 is a perspective view showing the main parts of the same embodiment, and Fig. 3 is 3-3 in Fig. 2.
4 is a sectional view taken along line 4-4 in FIG. 2, FIG. 5 is a sectional view taken along line 5-5 in FIG. 4, and FIG. 6 is a sectional view taken along line 5-5 in FIG. Perspective view of main parts showing another embodiment, No. 7
The figure is a vertical cross-sectional view showing an example of the conventional device, and FIG. 8 is a vertical cross-sectional view of essential parts showing the other side of the conventional device. 12... Valve chamber, 12a... Opening edge, 13... Cylinder, 14... Crank case, 15... Crank chamber, 16...
... Breather hole, 25 ... Partition wall, 26 ...
...Opening direction, 27...Recess.

Claims (1)

[Scope of utility model registration request] In a breather device for a side valve type engine in which a valve chamber is integrally formed in the crankcase and the valve chamber and the crank chamber are communicated through a breather hole, one end of the valve chamber is connected to the partition wall between the crank chamber and the above-mentioned valve chamber. A recess is formed that opens at the opening edge of the valve chamber and extends in the opening direction of the valve chamber. A breather device for a side valve type engine characterized by a breather hole.