JP2501535Y2 - Two-cycle engine intake pipe - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Use) The present invention relates to an intake pipe of a two-cycle engine for connecting a carburetor and a cylinder or a crankcase.

(Prior Art) FIG. 5 shows a motorcycle equipped with a two-cycle engine.

The engine a is arranged in the center of the vehicle body, the exhaust pipe c is connected to the front edge of the cylinder b, and the intake pipe d is connected to the rear edge of the cylinder b.

The intake pipe d connects the rear caplet e and the cylinder b, and is often made of rubber in order to attenuate intake noise. An air cleaner case f is connected behind the carburetor e.

On the other hand, the rear wheel g is buffered by one cushion unit h. As shown in FIG. 4, the cushion unit h is arranged on the vehicle body center line XX, is linked to the swing arm j via a link mechanism i, and has an upper end that intersects with the air cleaner case f and is of a frame. Partially supported.

Therefore, in order to avoid buffering with the cushion unit h, the air cleaner case f has a layout in which, for example, as shown in FIG. 4, the outlet k portion is detoured to one side and connected to the carburetor e. Also, the carburetor e
Is also deviated to one side from the center line XX, and the intake pipe d is connected so as to be introduced into the cylinder b from an oblique side.

That is, the intake port d has its center opened on the center line XX, and the center line YY of the intake pipe d is θ with respect to a straight line which coincides with the center line XX when viewed from the cylinder axis direction. The layout will be inclined.

Since the intake air-fuel mixture is naturally introduced in the direction of the center line Y-Y, it has an uneven distribution of introduction to the cylinder b. The air-fuel mixture has a function of hitting the piston to cool it, and in this case, the temperature distribution of the piston becomes non-uniform, resulting in a thermal problem.

Therefore, the applicant of the present invention has proposed an intake device in which a guide wall that divides the inside of the passage into two parts is integrally formed at the exit end of the intake pipe d with a surface that substantially coincides with a straight line passing through the center of the intake port d (special feature). See Japanese Patent Application No. 1-136151). According to this intake device, it is possible to uniformly introduce the air-fuel mixture into the piston, uniformize the temperature of the piston, and eliminate the thermal trouble.

(Problems to be solved by the invention) However, if the guide wall is integrally provided on the intake pipe, the mold becomes complicated at the time of production, leading to an increase in cost.

In addition, when the intake pipe is manufactured by a complicated mold, the product is cracked due to excessive removal, and the defective rate increases, leading to an increase in cost.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an intake pipe for a two-cycle engine that can reduce the cost by simplifying the mold for manufacturing the intake pipe.

[Constitution of device]

(Means for Solving the Problems) In order to achieve the above object, the present invention connects a carburetor and a cylinder or a crankcase with an intake pipe, the center line of which is the center of the intake port when viewed from the cylinder axial direction. In the intake structure of the two-cycle engine, which has an introduction direction that is inclined to one side with respect to the passing straight line,
At the outlet end of the intake pipe on the intake port side, a guide wall that divides the inside of the passage into two parts with a surface that substantially coincides with the straight line is provided, and the guide wall has upper and lower ends engaged with a long groove formed in the pipe body. It is characterized in that the reed valve body is pressed from the intake port side by being assembled together and installed vertically.

(Operation) The guide wall is installed by engaging the upper and lower ends with the long groove formed in the pipe body and pressed by the reed valve from the intake port side, so the guide wall and the pipe body are produced as separate bodies and assembled. be able to. Therefore, the mold at the time of production can be simplified to reduce the cost, and the defective rate of the product can be reduced to reduce the cost.

(Embodiment) An embodiment of the intake pipe of the two-cycle engine according to the present invention will be described below with reference to the accompanying drawings.

1 to 3, the intake pipe 1 is a rubber pipe that connects the carburetor and the cylinder, the inlet side of the carburetor is inserted and fastened with a band, and the outlet side is attached to the cylinder by the attachment flange 3. Mounted. Reference numeral 4 is a reinforcing material inserted in the attachment flange 3.

The attachment flange 3 is integrally formed with the pipe body 1a at a set angle of θ. Therefore, when the intake pipe 1 is attached to the cylinder, the intake pipe 1
The center line Ya−Ya is a straight line Za− that passes through the center of the intake port.
It is inclined by θ with respect to Za.

The outlet end of the intake passage 5 in the intake pipe 1 is divided into right and left by a flat guide wall 6 that substantially coincides with the straight line Za-Za. The guide wall 6 is vertically installed by engaging the upper and lower ends with the long groove 7 formed in the pipe body 1a,
The reed valve body 8 is pressed and fixed from the intake port side. The reed valve body 8 and the attachment flange 3 of the intake pipe 1 are fixed by a bolt (not shown).

Nipples 9a and 9b are provided in the divided passages 5a and 5b divided by the guide wall 6, respectively, and communicate with each other through a resonance volume tube (not shown).

The air-fuel mixture sucked from the carburetor passes through the intake passage 5 and is temporarily separated into the divided passages 5a and 5b at the outlet end and introduced into the cylinder. In this case, as shown in FIG. 1, in the divided passage 5a on the obtuse angle side (outer side) with respect to the inclination angle θ, the air-fuel mixture is introduced substantially along the inclination angle θ, and therefore more is supplied to one side end of the piston. To be done. On the other hand, in the acute-angled (inner) divided passage 5b, the guide wall 6 changes the flow direction to the straight line Za-Za direction and is introduced.

At the upstream end of the guide wall 6, the sectional area of the inner divided passage 5b is larger than that of the outer divided passage 5a due to the angle θ, and a larger amount of air-fuel mixture flows into the inner divided passage 5b. Then, it is introduced by changing the flow in the straight line Za-Za direction. In this way, the left-right uniform air-fuel mixture is supplied to the piston as a whole, the temperature distribution of the piston is made uniform by the cooling action, and the thermal trouble caused by the uneven temperature distribution is eliminated.

As described above, according to the above-described embodiment, the guide wall 6 is vertically installed by engaging the long grooves formed in the pipe body 1a with the upper and lower ends thereof, and from the intake port side, the reed valve body 8 is installed.
The pipe body 1a and the guide wall 6 can be manufactured and assembled separately as they are pressed and fixed by.
Therefore, the mold at the time of producing the intake pipe 1 is simplified, and the cost can be reduced. In addition, the defect rate of the product is reduced by the simplification of the mold, and the cost can be reduced.

[Effect of device]

The intake pipe of the two-cycle engine according to the present invention is provided with a guide wall at an outlet end on the intake port side that divides the intake passage into two parts, and the guide wall has upper and lower ends engaged with a long groove formed in the pipe body. The pipe body and the guide wall can be separately manufactured and assembled because they are combined and installed vertically and are pressed by the reed valve body from the intake port side. Therefore, the mold at the time of production of the intake pipe can be simplified and the cost can be reduced, and the defect ratio of the product can be reduced by the simplified mold, and the cost can be reduced.

[Brief description of drawings]

FIG. 1 is a transverse sectional view showing an intake pipe of a two-cycle engine according to the present invention, FIG. 2 is a front view showing the above embodiment, FIG. 3 is a vertical sectional view showing the above embodiment, and FIG. FIG. 5 is a plan view showing the arrangement of the system, and FIG. 5 is a side view showing a motorcycle equipped with the intake system of FIG. 1 ... Intake pipe, 1a ... Pipe body, 3 ... Attachment flange, 5 ... Intake passage, 5a, 5b ... Dividing passage, 6 ... Guide wall, 7 ... Long groove, 8 ... Reed valve body, Ya-Ya ... Intake pipe 1 Center line of Za-Za ... A straight line that passes through the center of the intake port.

Claims (1)

(57) [Scope of utility model registration request] 1. A carburetor and a cylinder or a crankcase are connected by an intake pipe, and a center line thereof has an introduction direction inclined to one side with respect to a straight line passing through the center of the intake port when viewed from the cylinder axial direction. In the intake structure of a two-cycle engine, a guide wall 6 that divides the inside of the passage into two is provided at the outlet end portion of the intake pipe 1 on the intake port side, the surface being substantially coincident with the straight line Za-Za. Is a long groove 7 formed in the pipe body 1a
An intake pipe for a two-cycle engine, characterized in that the upper and lower ends thereof are engaged with each other and installed vertically, and are pressed by the reed valve body 8 from the intake port side.