JP2556039Y2 - 4 cycle engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application field] The present invention relates to a four-stroke engine, and particularly to an improved connection means between a breather chamber and an intake system.

[Prior Art] A breather chamber is a space that communicates with a crank chamber and is connected to an intake system (such as an air cleaner section and an intake pipe). ) To separate oil (lubricating oil) from gas. That is, the oil gas flowing into the chamber is decelerated and decompressed in a room having a sufficient volume and separated into oil and gas,
Oil is returned to the crank chamber through a return hole (small hole for drain), and gas is supplied to the intake system.

FIG. 2 is a sectional view of a conventional four-cycle engine having a general breather chamber. In FIG.
Reference numeral 2 denotes a cylinder head, reference numeral 3 denotes a muffler, and reference numeral 4 denotes an intake pipe. Reference numeral 5 denotes a crankshaft penetrating through the crankcase 1, and a flywheel 6 with a fan is attached to an end thereof. The breather chamber 10 is a space surrounded by a peripheral wall 11 provided on the wall surface of the crankcase 1 and a cover (not shown) fixed on the peripheral wall 11 by bolts 12 and having a check valve 13. The passage 14 communicates with the inside of the crankcase 1 (crank chamber). The short pipe 17 attached to the peripheral wall 11 and the breather tube 18 connected to the short pipe 17 are connected to the intake pipe 4 which is a part of the intake system.

As shown in the figure, in a conventional four-cycle engine, a passage connecting the breather chamber and the intake system is formed by a so-called pipe such as a tube, a hose, and a metal pipe. This applies to the engine described in Japanese Utility Model Publication No. Sho 62-24739, for example.

[Problem to be Solved by the Invention] As is clear from FIG. 2 (and FIG. 2 in the above-mentioned publication), the pipe connecting the breather chamber and the intake system usually has a considerable length. This is because the breather chamber is almost inevitably provided just outside the crankcase, whereas the intake system is often functionally located closer to the cylinder head (for a four-stroke engine).

The fact that the pipe is long actually has the following disadvantages. That is, a) When used in a cold region, the gas moving in the piping is cooled, and the water vapor in the gas freezes, which may cause a problem in the intake system.

B) Long (and therefore expensive) piping (tubes, etc.)
Is necessary, and a clamp (fixing tool) for fixing the piping is also indispensable, which raises the cost of the engine in terms of both parts and assembly costs.

C) Since there are many restrictions such as that the piping does not contact the flywheel and various control links, it is difficult to easily determine the piping route. In order to avoid such contact, it may be necessary to increase the overall size of the engine.

D) If the piping path is unnecessarily long for the reason (c), the resistance of the gas passing through the piping increases, and oil tends to accumulate on the way.

An object of the present invention is to eliminate the above-mentioned inconvenience by making the piping such as a tube connecting the breather chamber and the intake system as short as possible, and keeping the temperature of the connection path high. is there.

[Means for Solving the Problems] The four-stroke engine of the present invention has a passage with a check valve that allows only the inflow of oil from the crankcase, and a return hole for oil into the crankcase. A breather chamber having a volume capable of separating oil and gas in it is formed through one or more of a crankcase, a cylinder, and a cylinder head through a vent having no components therein. It is connected to the intake pipe on the upstream side of the carburetor by piping such as a tube (in the near part).

[Operation] An engine having a breather chamber near a crankcase and an intake system near a cylinder or a cylinder head. The temperature of the gas passage including the pores increases, and the water vapor in the gas that passes through the gas passage and reaches the intake system hardly freezes. Further, piping such as a tube required between the breather chamber and the intake system is shortened accordingly. This is because the breather chamber and the intake system are connected by using the above-mentioned ventilation hole instead of a part of the pipe. When the piping is shortened, a clamp or the like for fixing the piping is not required, or the required number is reduced, and the setting (routing) of the piping path becomes easy.

Even if the breather chamber is connected to the intake system via such a vent, it has the same oil-gas separation function as the conventional case where it is connected to the intake system only by piping. The above-mentioned ventilation hole can be formed in a straight line with a path as short as possible between the same chamber and the intake system. Further, the breather chamber is provided with a means for performing oil / air separation, a check valve, and the like. Considering that there are no such components inside the pores, it can be said that the function of the same room is rather improved in that the resistance of the gas passing through the vents is small and the oil pool is hardly generated in the vents. . Because there are no parts inside the ventilation holes,
There is also an advantage that no trouble is required in mounting and cleaning those parts.

[Embodiment] Fig. 1 shows an embodiment of the present invention. The illustrated engine is a so-called vertical axis (vertical) general-purpose four-cycle engine in which a crankshaft is arranged vertically, and is used as a drive source of a lawnmower. The figure is a plan view of the engine, which is partially cut away, and will be described below based on this.

The crankshaft 5, which is the output shaft of the engine, penetrates vertically through the crankcase 1, and its lower end (not shown) projects below the crankcase 1 as an output end. So that a flywheel 6 with a fan is attached. Since the crankshaft 5 is vertical, a piston (not shown) connected to the crankshaft 5 reciprocates in a horizontal direction inside a cylinder portion 1a formed integrally with the crankcase 1. A cylinder head 2 is fixed at the end of the cylinder portion 1a. In the vicinity of the cylinder head 2a, a part of an intake system following an intake pipe 4-air cleaner (not shown) is provided. Through the intake passage-which extends to the inside of the cylinder portion 1a.

Lubrication of each part in the crankcase 1 is performed by an oil bath stored at the bottom and an oil mist splashed from the oil bath. Therefore, the inside of the crankcase 1 is filled with oil, that is, blow-by gas containing oil mist.

The breather chamber 10, which is a space for introducing the oil and avoiding a pressure increase in the crankcase 1 and separating the oil into oil and gas, is located on the upper surface of the crankcase 1, that is, below the flywheel 6. It is provided in. In the figure, reference numeral 11 denotes a peripheral wall formed on the crankcase 1 so as to surround the breather chamber 10, and a cover (not shown) is attached thereto by bolts 12 to form a space. The inside of the crankcase 1 is communicated with a breather passage 14 having a check valve 13. Reference numeral 15 in the drawing denotes a return hole for oil into the crankcase 1, and reference numeral 16 denotes a shaft end of a camshaft.

In this engine, ventilation holes 1h and 2h are respectively formed in the crankcase 1 (cylinder portion 1a) and the cylinder head 2 as a part of a gas passage from the breather chamber 10 to the intake pipe 4. Vent 1h
Is formed by casting during the casting of the crankcase 1 so as to connect the mating surface with the cylinder head 2 and the inside of the breather chamber 10. The air hole 2h is formed by casting at the time of casting the cylinder head 2 so as to be connected to the air hole 1h at the mating surface. Vent 2h
Reaches the side position of the intake pipe 4,
A hole was made in that position, and a short pipe 17 was driven in from the outside to fix it, thereby forming a connection portion to the intake pipe 4. The short pipe 17 and the resin intake pipe 4 (a similar short pipe (not shown) is formed) are connected by a rubber tube 18.

Since the ventilation holes 1h and 2h are part of the gas passage as described above, the length of the tube 18 is considerably shorter than that of a conventional engine (for example, FIG. 2). Since the tube 18 is short, a fixture (clamp) is not required in the middle portion, and no consideration is required for the passage of the tube 18 and the prevention of bending thereof. In addition to the fact that the path of the tube 18 and the ventilation holes 1h and 2h has become substantially straight, the total length of these tubes is also a conventional tube (for example, the symbol in FIG. 2).
18) shorter. Therefore, in this engine, the transmission capability of the negative pressure from the intake pipe 4 to the breather chamber 10 was excellent, and the oil-gas separation in the breather chamber 10 was also enhanced.

In the above, one embodiment has been introduced based on FIG. 1. In addition, the present invention can be carried out as follows.

1) In the example of FIG. 1, the opening of the ventilation hole 1h may be provided, for example, at the side of the crankcase 1 (at a position close to the intake pipe 4), and the opening may be connected to the intake pipe 4 by a tube or the like. In this case, it is not necessary to form a ventilation hole in the cylinder head 2, but an effect comparable to the above example, such as a reduction in the length of the tube, is obtained.

B) Unlike the above example, in an engine having a cylinder as a separate part from the crankcase, the vent may be formed through three parts of the crankcase, the cylinder, and the cylinder head, or through one or more of them.

C) It goes without saying that the present invention can be applied to engines other than the vertical axis type as shown in the examples.

D) If the short pipe portion of the intake pipe 4 is extended, a rubber O-ring can be used instead of the tube 18.

[Effect of the Invention] In the four-stroke engine of the present invention, the piping such as the tube for connecting the breather chamber and the intake system is short, and the connection passage passes through a high-temperature portion such as a cylinder.
The following effects are obtained.

1) Since the gas moving from the breather chamber to the intake system is not easily cooled, water vapor in the gas is hardly frozen.

2) In terms of parts costs and assembly costs for the piping itself and clamps (fixing tools) for fixing the piping,
Engine cost is reduced.

3) It is easy to determine the route of piping. Therefore, it is not necessary to increase the size of the entire engine to secure the path.

4) The ventilation performance to the intake system is improved, and the function of the breather chamber is improved.

5) Since there are no components inside the ventilation holes, there is no need for labor for mounting and cleaning those components.

[Brief description of the drawings]

FIG. 1 shows one embodiment of the present invention, and is a plan view of a vertical axis type four-stroke engine with a part cut away. FIG. 2 is a similar drawing showing a conventional four-stroke engine. 1 ... Crankcase, 1a ... Cylinder part, 2 ... Cylinder head, 1h / 2h ... Ventilation hole, 4 ... Intake pipe (intake system), 10 ... Breezer chamber.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Akio Amiguchi 1-1, Kawasaki-cho, Akashi-shi, Hyogo Kawasaki Heavy Industries, Ltd. Akashi Plant JP 38-7712 (JP, Y1)

Claims (1)

(57) [Scope of request for utility model registration] 1. A passage having a check valve that allows only the inflow of oil and gas from a crankcase, and a return hole for oil into the crankcase, and has a volume capable of separating oil and gas in the oil and gas. A breather chamber is formed through at least one of the crankcase, the cylinder, and the cylinder head, and is connected to an intake pipe on the upstream side of the carburetor through a pipe through an air hole having no components therein. A four-stroke engine, characterized in that: