JPS6327047Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a rotary valve for controlling the intake air of a two-stroke engine. This invention relates to a rotary valve that opens and closes the intake path by rotating it by a valve drive shaft arranged at a predetermined angle.

[Conventional technology]

A rotary valve in a two-stroke engine is a valve that opens and closes an intake path at a certain timing with respect to the rotation angle of the crank, and supplies air-fuel mixture or fresh air to the crank chamber of the two-stroke engine. The most popular conventional rotary valve of this type has a rotary disk, which is the valve body, mounted in a floating state on the side shaft of the crank on the side of the crankcase, and a carburetor placed on the side of the rotary disk to evaporate the gas. The air intake path between the engine and the crankcase is opened and closed. When such a configuration is adopted, for example, it is necessary to attach a carburetor to one side of the crankcase of a two-stroke engine, and for this reason, such conventional means can only be used for single-cylinder, tandem, or parallel two-cylinder engines. It cannot be configured.
For this reason, in order to have a multi-cylinder engine even though it was equipped with rotary valves, it was necessary to combine the engines for every two cylinders and arrange them front and rear or up and down as appropriate to form a so-called square-type engine.

In order to eliminate the inconvenience caused by such conventional rotary valves, the inventor of the present invention created an intake path behind each crank chamber of each cylinder, and installed one rotary valve in each intake path. We have already developed and proposed a parallel multi-cylinder engine with two or more cylinders, which is equipped with a rotary valve. As shown in Fig. 1, a timing shaft 3 is provided in parallel below a crankshaft 2 disposed in a crankcase 1, and a timing shaft 3 is connected to the crankshaft 2 through an appropriate gear or chain. The rotation is transmitted to the timing shaft 3 at a constant timing, and the valve drive shaft 4 is disposed upwardly in the crankcase 1 at a required angle with respect to the intake path to the crank chamber, and the lower end of the shaft 4 A gear 5 provided on the timing shaft 3 meshes with a gear 6 provided on the timing shaft 3 to rotate the valve drive shaft 4. A rotary disk 8, which is a disk-shaped valve body and partially having an intake hole 7, is provided at the tip of the valve drive shaft 4, and is configured to open and close an intake pipe 9. Note that 11 is a cylinder, 2 is a piston,
13 is a connecting rod, 14 is a scavenging hole, and 15 is an exhaust hole.

[Problem that the invention attempts to solve]

Although such prior art can overcome the drawbacks of conventional rotary valves placed on the side,
A flat disk-shaped rotary disk 8 is installed at the rear of the crankcase 1 at an angle with respect to the axis of the intake path, so that the distance between the crankshaft 2 and the opening/closing portion of the intake path by the rotary disk 8 is Because of the length, there was a limit to improving the primary compression ratio in the crank chamber, making it impossible to improve output in the high rotation range. Incidentally, if the primary compression ratio improves, the amount of fresh air sent into the combustion chamber generally increases, which improves the output, especially in the high rotation range.

The object of the present invention is to further improve such prior art and provide a rotary valve for a two-stroke engine that improves the output in the high-speed rotation range.

[Means for solving problems]

The structure of the present invention is that the valve body is formed into a hollow inverted conical shape, and the tip of the valve rotating shaft is connected to the top of the valve body, and the axis of the valve body is aligned at a position where the conical surface of the valve body crosses the intake path. It is characterized by being arranged so as to be almost orthogonal to the

[Effect]

With this configuration, the intake path between the crankshaft and the opening/closing portion of the intake path of the valve body can be shortened.

〔Example〕

The present invention will be specifically explained below based on the embodiments shown in FIGS. 2 to 4.

FIG. 2 is a longitudinal sectional side view showing an embodiment of a two-stroke engine to which the present invention is applied, and the same reference numerals are used for the same parts as in FIG. 1.

The valve drive shaft 4 is disposed in the crankcase 1 at a predetermined angle with respect to the intake path, and has an intake hole 17 that serves as an intake area at the tip. A valve body 18 is provided.

That is, the tip of the valve drive shaft 4 is connected to the top of the hollow inverted conical valve body 18, and the valve body 1
The valve body 18 is arranged so that the conical surface of the valve body 18 is substantially orthogonal to the axis of the intake passage at a position where it crosses the intake passage, thereby shortening the distance between the crankshaft 2 and the opening/closing portion of the intake passage of the valve body 18. Further, if the valve body 18 is formed into an inverted conical shape, the valve drive shaft 4
It becomes easy to ideally design the angle θ formed by the axis of the drive shaft 4 and the conical surface of the valve body with respect to the angle formed by the intake path.

However, when the engine starts, the crankshaft 2
The timing shaft 3 rotates in response to the rotation, which rotates the valve drive shaft 4 and the valve body 18 rotates. When the piston 12 rises, which is the normal intake timing, the valve body 18 further rotates and the intake air The intake pipe 9 is closed at a portion other than the hole 17.

FIG. 3 is a longitudinal cross-sectional view showing another embodiment of a two-stroke engine to which the present invention is applied, in which the valve body 18' has an inverted conical shape with an intake hole 17'. In order to maintain the balance, a gap 19 is provided by stealing some of the meat, and the same effect as in the previous embodiment is achieved.

FIG. 4 is a sectional view showing an embodiment of the present invention applied to a V-type two-stroke engine. The reciprocating motion of the pistons 12, 12 is controlled by the connecting rod 1.
3 and 13 to rotate the crankshafts 2 and 2, and this rotation is transmitted from the crank side drive gears 2a and 2a to the transmission side drive gear 16a to drive it. A timing shaft 3 is located between both crankshafts 2, 2.
is arranged parallel to the crankshafts 2, 2, and the transmission side drive gear 16a meshes with the gear 3a attached to the shaft 3, rotating the timing shaft 3 in conjunction with the rotation of the engine, and rotating the gear 6 and the gear 3a. The valve drive shaft 4 is rotated through the valve drive shaft 5.

Connected to the tip of the valve drive shaft 4 is the top of an inverted conical valve body 18'' having intake holes 17'', 17'' for opening and closing the intake pipes 9, 9, respectively.
Note that 19 is a gap for balancing the intake holes 17'', 17''.

In this way, in a V-type engine, one rotary valve can serve two cylinders.

[Effect of idea]

As described above, the present invention forms the valve body in an inverted cone shape, and connects the valve drive shaft to the top of the valve body to make it look like a cocktail glass, and arranges the conical surface of the valve body at a position that crosses the intake passage and is almost perpendicular to its axis, so that while inheriting the effects achieved by the prior art shown in Figure 1, the distance between the crankshaft and the opening and closing part of the intake passage can be shortened regardless of the position of the timing shaft, improving the primary compression ratio in the crank chamber, increasing the amount of fresh air sent into the combustion chamber, improving the power output especially in the high rotation range, and making the valve itself more compact. Also, by forming the valve body in an inverted cone shape, even if the mounting angle of the valve drive shaft differs depending on the model, the angle between the axis of the valve drive shaft and the conical surface of the valve body can be changed to set the valve body relative to the axis of the intake passage.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal side view of a two-stroke engine equipped with a conventional rotary valve, FIG. 2 is a longitudinal side view of a two-cycle engine equipped with an embodiment of the rotary valve of the present invention, and FIG. 3 is a longitudinal side view of a two-stroke engine equipped with the rotary valve of the present invention. FIG. 4 is a longitudinal sectional view of a two-cycle engine equipped with another embodiment of the rotary valve of the present invention, and FIG. 4 is a longitudinal sectional view showing an embodiment in which the rotary valve of the present invention is applied to a V-type engine. 1...Crank case, 2...Crankshaft, 3
...Timing shaft, 4...Valve drive shaft,
9...Intake pipe, 18, 18', 18''...Valve body.

Claims (1)

[Scope of utility model registration request] A valve body with an intake hole is placed above the crankcase, and a valve drive shaft, which is placed at a required angle to the intake path into the crank chamber, is rotated in conjunction with a timing shaft that is spaced apart from the crankshaft. , in the rotary valve that opens and closes the intake passage, the valve body is formed into a hollow inverted conical shape, the tip of the valve drive shaft is connected to the top of the valve body, and the conical surface of the valve body crosses the intake passage. A rotary valve for a two-stroke engine, characterized in that the rotary valve is disposed substantially orthogonal to the axis of the rotary valve at a position where the rotary valve rotates at a right angle.