JPS6224739Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an improvement of a blazer device for a vertical shaft type engine.

Conventional blazer devices are configured to close the hole communicating with the crank chamber with a leaf spring valve, and allow the gas in the crank chamber to flow out to the blazer chamber only when the internal pressure of the crank chamber rises to a positive pressure above a certain level. The structure was complicated and the assembly process cost was high. Furthermore, the operating performance of this Blazer device is directly affected by the characteristics of the leaf spring valve, but the characteristics of the leaf spring valve tend to change greatly depending on the assembly accuracy, and for this reason, the operating performance of the Blazer device varies from device to device. It was easy to vary.

Therefore, we developed a structure that eliminates the leaf spring valve, which has a large effect on the blazer's operating performance, to eliminate the above drawbacks.
There is one shown in Publication No. 41055.

That is, the bearing boss of the crankshaft is formed on the upper wall of the crankcase, the blazer chamber is formed on the side wall of the crankcase, and the blazer chamber and the crank chamber are communicated through a blazer passage, and the inner surface of the crank arm is formed in the blazer passage. A passageway that opens and extends upward along the axial direction of the crankshaft and an annular recess formed in the upper part of the bearing boss of the crankshaft are interposed, and the passageway of the crankshaft is opened only when the crankshaft is at a certain angular position. The annular recess of the bearing boss and the crank chamber are communicated through the crankshaft, and the crankshaft itself is also used as a rotary valve that disconnects communication between the crank chamber and the Blazer chamber.

However, the structure shown in the above-mentioned Japanese Utility Model Publication No. 56-41055 has the following drawbacks.

(a) Since the blazer chamber is located on the side wall of the crankcase, the structure allows oil in the crankcase to easily flow into the blazer chamber when the engine is tilted.

Therefore, the bearing boss of the crankshaft, which is usually located near the center of the crankcase, forms a passage that is first directed upward and then directed downward to prevent access to the blazer chamber when the engine is tilted. This is to prevent oil from entering.

For this reason, the blazer passage that connects the blazer chamber and the crank chamber has a long and complicated shape.
Processing during manufacturing becomes complicated and expensive.

(b) Inside the crankshaft, a long passage is formed that connects the crank chamber and the annular recess of the bearing boss, extending from the inner surface of the crank arm to above the crankshaft, which increases the strength of the crankshaft. significantly reduced, and durability is poor.

This idea forms a bearing boss that supports the crankshaft on the upper wall of the crankcase of a vertical-shaft engine, and also arranges a Blazer chamber in close proximity to this bearing boss. A hole that communicates with the crank chamber and a hole that communicates between the shaft insertion hole and the Blazer chamber are respectively drilled in the crankshaft. By forming a passage that communicates both holes, the objective is to provide excellent blazer performance and to simplify processing during manufacturing.

Examples of this invention will be described below based on the drawings.

Figure 1 shows a vertical shaft type single cylinder gasoline engine mounted on a small agricultural management machine (Taylor).The engine body 1 is directly mounted and connected on an axle transmission case 2, and is supported vertically on a crankcase 3. The lower end of the crankshaft 4 protrudes as an output shaft to the transmission case 2, and
A flywheel 6 with a cooling fan 5 and a recoil starter 7 are attached to the upper end of the crankshaft 4 protruding from the upper surface, and a fuel tank 8 is attached above the cylinder head, and a fuel tank 8 is attached to the left and right sides of the engine body 1. A muffler 9, an air cleaner 10, and a carburetor 11 are respectively provided in the section.

A blazer chamber 13 is provided on the side of the crankshaft support receiving boss 12 protruding from the upper surface of the crankcase 3.
are integrally formed in the boss 12, and a hole 15 that communicates between the crank chamber 16 and the crankshaft insertion hole 14, and a hole 17 that communicates between the crankshaft insertion hole 14 and the Blazer chamber 13.
A series of drill holes are drilled diagonally downward from the blazer chamber opening so that the vertical height of the opening end is different. Furthermore, the portion of the crankshaft 4 that is inserted into the boss 12 is provided with a shaft 1
4 corresponds to the vicinity of the lowest point of the piston, a passage 18 that communicates both the holes 15 and 17 is bored as a drilled hole diagonally passing through and across the crankshaft 4. Every time 4 rotates, the blow-by gas in the crank chamber is transferred to the blazer chamber 1 near the lowest point of the piston, that is, at the timing when the internal pressure of the crank chamber 16 is at its highest.
3.

In addition, an exhaust hose 20 led out from a lid 19 that closes the upper part of the blazer chamber 13 connects to the air cleaner 10.
The blazer chamber 13 is connected to the blazer chamber 13, and is configured to reduce and reuse unburned gas contained in the outflow gas from the blazer chamber 13.

As another structure in which the crank chamber 16 and the blazer chamber 13 are communicated with each other at a constant rotational phase each time the crankshaft 4 rotates, for example, as shown in FIG. In addition to providing the same phase in the direction with different heights, it is also possible to cut out and form a recessed part as a passage 18 communicating with both holes 15 and 17 in a part of the outer peripheral surface of the crankshaft 4. .

Further, the phase of communication between the crank chamber 16 and the blazer chamber 13 may be configured such that communication starts a little before the lowest point of the piston and closes a little beyond the lowest point of the piston, and,
In this case, if the hole 17 that communicates with the blazer chamber 13 is opened at the bottom of the blazer chamber 13, the oil separated and stored in the blazer chamber 13 can be pumped out at the beginning of communication between the crank chamber 16 and the blazer chamber 13. It becomes possible to flow back into the chamber 16.

In addition, as a means for reducing separated oil, the crankshaft 4
Both holes 15, 17 are in a phase different from the passage 18.
It is also possible to provide a passage that communicates the separated oil and return the separated oil to the crank chamber 16 through the holes 15 and 17 when the internal pressure of the crank chamber 16 is low.

The configuration as described above provides the following effects.

(b) The blazer chamber is located close to the crankshaft bearing on the upper wall of the crankcase, so that the blazer chamber is located near the center of the upper wall of the crankcase, making it difficult for oil to flow into the blazer chamber when the engine is tilted. This greatly improves the engine's tilting performance.

(b) As mentioned above, by arranging the blazer chamber close to the crankshaft bearing on the upper wall of the crankcase, the tilting performance of the engine has been greatly improved. If the structure is used as a rotary valve that cuts off communication, the path for the blazer from the crank chamber to the blazer chamber will be short and simple in shape, and processing during manufacturing will be simple and inexpensive.

C. A hole that communicates the shaft insertion hole with the crank chamber and a hole that communicates the shaft insertion hole with the Blazer chamber are drilled in the bearing boss of the crankshaft, so a passage is formed in the crankshaft that communicates both of the holes. Just do it and you'll get better. Therefore, the passage formed in the crankshaft is shortened, resulting in excellent durability.

[Brief explanation of the drawing]

The drawings show an embodiment of this invention, in which Fig. 1 is a vertical sectional side view of the entire engine, Fig. 2 is a cross-sectional plan view, Fig. 3 is a sectional view taken along line A-A in Fig. 1, and Fig. 4 is a different side view of the engine. FIG. 2 is an enlarged longitudinal cross-sectional side view of main parts showing an example. 4...Crankshaft, 12...Bearing boss, 13...
...Blazer chamber, 14...Shaft insertion hole, 15...Hole,
16...crank chamber, 17...hole, 18...passage.

Claims (1)

[Claims for Utility Model Registration] 1. A bearing boss 12 for supporting the crankshaft 4 is formed on the upper wall of the crankcase 3, and a blazer chamber 13 is disposed close to the bearing boss 12. A hole 15 that communicates between the shaft insertion hole 14 and the crank chamber 16 and a hole 17 that communicates the shaft insertion hole 14 and the Blazer chamber 13 are formed in the crankshaft 4, and a piston lowest point is formed in the crankshaft 4. Only at a constant rotational phase corresponding to or in the vicinity thereof, both the holes 15, 17
A blazer device for a vertical shaft engine, characterized in that a passage 18 is formed to communicate with the blazer device. 2. Both the holes 15 and 17 are opened into the shaft insertion hole 14 with different phases in the boss shaft locking direction, and
The Blazer device for a vertical shaft type engine according to claim 1, wherein the passage 18 is formed as a through hole that crosses the crankshaft 4 diagonally with respect to the axis. 3. The Blazer device for a vertical shaft engine according to claim 1, wherein the passage 18 of the crankshaft 4 is configured as a recessed portion with a portion of the outer peripheral surface of the shaft 4 removed.