JP3739025B2 - Rubber parts for pipe intake - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pipe intake rubber member that is provided in an intake passage between a carburetor and an engine cylinder and used as a mist in a connecting portion of an intake pipe through which a mixture of gasoline and air passes.
[0002]
[Prior art]
FIG. 4 shows an outline of a general motorcycle engine, and FIG. 5 shows a cross section of a conventional pipe intake.
[0003]
In a typical motorcycle engine, as shown in FIG. 4, a cylinder 12 is formed in the engine body 11 along the vertical direction, and a piston 13 is mounted in the cylinder 12 so as to be movable up and down. Yes. The piston 13 is connected to an eccentric portion 16 of the crankshaft 15 via a connecting rod 14. A combustion chamber 18 is formed by fixing the cylinder head 17 to the upper part of the engine body 11, a spark plug 19 faces the combustion chamber 18, and an intake port 20 and an exhaust port 21 are exposed to the combustion chamber 18. In communication, the intake port 20 is provided with a reed valve 22. A carburetor 24 is connected to the intake port 20 via a pipe intake 23, and a fuel tank and an intake port (not shown) are connected to the carburetor 24.
[0004]
Accordingly, a mixture of gasoline and air is supplied from the carburetor 24 to the cylinder 12 side, the reed valve 22 is opened by the stroke of the piston 13, and the mixture is supplied from the intake port 20 into the cylinder 12. Here, the air-fuel mixture is ignited by the spark plug 19 according to the stroke of the piston 13, so that the air-fuel mixture compressed in the combustion chamber 18 explodes and rotates the crankshaft 15 via the connecting rod 14.
[0005]
As described above, the intake port 20 of the engine body 11 and the carburetor 24 are connected to the above-described motorcycle engine by the pipe intake 23. As shown in FIG. 5, the pipe intake 23 is formed in a cylindrical shape slightly curved by a rubber member, and a fitting portion 23 a into which the outer peripheral portion of the connecting tube 25 is fitted is formed at one end portion. The connecting pipe 25 is made of aluminum, and is integrally formed with a flange part 25 a fixed to the end face of the intake port 20 and a connecting part 25 b fitted to the pipe intake 23. And the fitting part 23a of the pipe intake 23 is formed by expanding the inner peripheral part, and when the connecting part 25b is fitted and bonded, the inner peripheral face of the fitting part 23a and the inner peripheral face of the connecting part 25b Are connected without any step. On the other hand, the outer peripheral portion of the connecting pipe 26 of the carburetor 24 is fitted to the other end portion of the pipe intake 23. A gasket 27 is interposed between the flange portion 25 a and the intake port 20.
[0006]
By the way, although the engine body 11 and the carburetor 24 are mounted on the vehicle body, the engine body 11 vibrates when driven. Therefore, the conventional pipe intake 23 connecting the engine body 11 and the carburetor 24 is formed of a rubber member. Has been.
[0007]
[Problems to be solved by the invention]
However, since a mixture of gasoline and air passes through the pipe intake 23, the inner surface of the pipe intake 23 is always exposed to gasoline, and rubber absorbs gasoline and swells due to long-term use. There is a problem. That is, the inner surface of the pipe intake 23 expands toward the center, and as shown in FIG. 6, in the fitting portion 23 a that fits with the connecting pipe 25, the protruding portion A is formed on the end surface portion. If the protrusion A is formed in the pipe intake 23, the inner diameter becomes narrow, the flow of the air-fuel mixture supplied from the carburetor 24 to the cylinder 12 becomes worse, and a predetermined amount of gasoline cannot be supplied to the cylinder 12. There is a problem in that it causes poor combustion and reduced output.
[0008]
In addition, when the protrusion A is formed and deformed in the pipe intake 23, there is a problem that the strength at this portion is reduced and a crack is generated by vibration.
[0009]
The present invention solves such a problem, and it is an object of the present invention to provide a rubber member for a pipe intake that suppresses expansion deformation inward due to adhesion of gasoline and stabilizes the flow of an air-fuel mixture. And
[0010]
[Means for Solving the Problems]
The present invention that solves the above problems is a rubber member for a pipe intake that is provided in an intake passage between a carburetor and an engine cylinder and is used for a connection portion of an intake pipe through which a mixture of gasoline and air passes through a mist. A pipe characterized in that a plurality of recesses are provided at substantially equal intervals along the circumferential direction on an inner peripheral surface that is continuous with at least one of the fitting portions of the fitting portion to which the connecting portion of the intake pipe is fitted. It is in the rubber member for intake.
[0011]
Here, in particular, it is preferably provided on the inner peripheral surface of the fitting portion on the cylinder side of the engine.
[0013]
Furthermore, the rubber material is not particularly limited as long as it is an oil resistant rubber. Examples of the oil-resistant rubber include acrylic rubber, fluorine rubber, polyurethane, acrylonitrile butadiene rubber (NBR), and hydrogenated acrylonitrile butadiene rubber (hydrogenated NBR), and NBR and H-NBR are particularly preferable.
[0014]
In particular, the durability can be improved by embedding a core material along the axial direction inside.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail based on the drawings.
[0016]
FIG. 1 shows a cross section of a pipe intake as an intake pipe according to the first embodiment of the present invention, and FIG. 2 shows a II-II cross section of FIG.
[0017]
In this embodiment, as shown in FIGS. 1 and 2, the pipe intake 31 communicates an engine cylinder (not shown) and a carburetor, and is connected to a connection pipe 25 and a carburetor fixed to an intake port via a gasket. The connecting pipe 26 is connected.
[0018]
The pipe intake 31 is made of oil-resistant rubber, preferably acrylonitrile butadiene rubber (NBR) or hydrogenated NBR, and is a tube slightly curved in accordance with the mounting positions of the connecting pipes 25 and 26. It has become a shape. The connecting pipe 25 is made of, for example, aluminum, and is integrally formed with a flange part 25 a that is fixed to the end face of the intake port and a connecting part 25 b that fits into the pipe intake 31. In addition, the connecting pipe 26 is made of, for example, a casting, and a connecting portion 26 a that fits into the pipe intake 31 is integrally formed.
[0019]
The pipe intake 31 is formed with a fitting portion 31a into which the outer peripheral portion of the connecting portion 25b in the connecting pipe 25 is fitted in one end portion, and the fitting portion in which the outer peripheral portion of the connecting portion 26a in the connecting pipe 26 is fitted into the other end portion. 31b is formed. The fitting portion 31a of the pipe intake 31 is formed by expanding the inner peripheral portion, and when the connecting portion 25b is fitted , an inner inner peripheral surface continuous to the fitting portion 31a and an inner peripheral surface of the connecting portion 25b. Are connected with no step.
[0020]
In the present embodiment, a plurality of groove portions (four in the present embodiment) as concave portions at equal intervals along the circumferential direction on the inner peripheral surface of the fitting portion 31a of the pipe intake 31 on the connecting pipe 25 side with the cylinder. 32 is formed. The length of the groove portion 32 is not particularly limited, but is generally 2 to 10 mm, preferably about 4 to 8 mm.
[0021]
Therefore, since the pipe intake 31 of the present embodiment is formed using NBR or hydrogenated NBR as a raw material, it is excellent in oil resistance, and a mixture of gasoline and air passes through and the gasoline adheres. However, the inward expansion deformation can be suppressed as much as possible.
[0022]
In addition, a plurality of groove portions 32 are formed at equal intervals in the circumferential direction in the fitting portion 31a of the pipe intake 31, and even if swelling deformation occurs due to long-term use, the swelling is absorbed by each groove portion 32. Therefore, a predetermined amount of gasoline is supplied to the cylinder without obstructing the flow of the air-fuel mixture supplied from the carburetor to the cylinder without projecting to the center side of the pipe intake 31 and reducing the combustion failure and output reduction. Can be prevented.
[0023]
Note that the pipe intake 31 of the present embodiment is formed by vulcanizing and injection molding a rubber composition.
[0024]
While blending is not particularly limited in the present invention, preferably, by adding an additive to improve ozone resistance, such as antioxidant Antage RD, it is possible to obtain an excellent pipe Intel Lee click environmental resistance .
[0025]
FIG. 3 shows a cross section of a pipe intake according to the second embodiment of the present invention. In addition, the same code | symbol is attached | subjected to the member which has the same function as what was demonstrated in embodiment mentioned above, and the overlapping description is abbreviate | omitted.
[0026]
In this embodiment, as shown in FIG. 3, the pipe intake 41 is made of NBR or H-NBR as a rubber material, and a woven fabric 43 such as nylon or polyester as a core material is embedded inside along the axial direction. Has been. The pipe intake 41 has a fitting portion 41a into which the outer peripheral portion of the connecting pipe 25 is fitted at one end portion, and a fitting portion 41b into which the outer peripheral portion of the connecting pipe 26 is fitted into the other end portion. And the groove part 42 as several recessed parts is formed in the internal peripheral surface of the pipe intake 41 near the fitting part 41a at equal intervals along the circumferential direction.
[0027]
Therefore, the pipe intake 41 of the present embodiment also has the same effect as the above-described embodiment. Furthermore, in the present embodiment, by incorporating the woven fabric 43, it is possible to prevent the occurrence of cracking of rubber due to vibration.
[0028]
In addition, the pipe intake 41 of this embodiment cuts two raw rubber sheets into a predetermined size, sandwiches a woven fabric of the same size between them, wraps this around a core, and then vulcanizes and molds it. It is formed by placing in the machine and vulcanization molding.
[0029]
Further, in each of the embodiments described above, the groove portions 32 and 42 as the concave portions are formed on the connecting tube 25 side with the cylinder, but may be formed on the connecting tube 26 side with the carburetor. Furthermore, although the four groove portions 32 and 42 are formed in the fitting portions 31a and 41a of the pipe intakes 31 and 41 at equal intervals in the circumferential direction, the number is not limited to this, and the amount of swelling of the material of the pipe intakes 31 and 41 is What is necessary is just to set together.
[0030]
Such a pipe intake is used in a connecting portion such as an intake passage between a cylinder and a carburetor of a 4-cycle, 2-cycle engine of a motorcycle.
[0031]
【The invention's effect】
As described above in detail in the embodiment, according to the present invention, the concave portion is provided on the inner peripheral surface of the fitting portion into which the connecting portion is fitted. Swelling is absorbed by each recess, protruding to the center of the pipe intake, the inner diameter is not narrowed, and a predetermined amount of gasoline is supplied to the cylinder without obstructing the flow of air-fuel mixture supplied from the carburetor to the cylinder In addition, it is possible to prevent combustion failure and output reduction. In particular, if a plurality of recesses are provided at equal intervals along the circumferential direction, the amount of swelling can be absorbed evenly, and the flow of the air-fuel mixture can be maintained satisfactorily by maintaining the inner circumferential surface as round as possible Can do.
[0032]
In addition, by using NBR or H-NBR as a rubber material, it is excellent in oil resistance and suppresses expansion deformation to the inside as much as possible even if a mixture of gasoline and air passes and the gasoline adheres. In addition, it is possible to stabilize the flow of the air-fuel mixture, and further, by adding an ozone degradation inhibitor, it is possible to effectively prevent the occurrence of cracks due to ozone cracks.
[0033]
Furthermore, since the core material along the axial direction is embedded inside, the strength can be increased and the durability can be improved, and cracking due to vibration can be effectively prevented.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a pipe intake as an intake pipe according to a first embodiment of the present invention.
FIG. 2 is a cross-sectional view taken along the line II-II in FIG.
FIG. 3 is a cross-sectional view of a pipe intake as an intake pipe according to a second embodiment of the present invention.
FIG. 4 is a schematic view of an engine of a general motorcycle.
FIG. 5 is a cross-sectional view of a conventional pipe intake.
FIG. 6 is a cross-sectional view showing a swollen state of a conventional pipe intake.
[Explanation of symbols]
31, 41 Pipe intake (intake pipe)
31a, 31b, 41a, 41b Fitting part 32, 42 Groove part (concave part)
43 Woven fabric (core material)

Claims (3)

In the rubber member for a pipe-in-take for use in the connecting portion of the intake pipe mixture of gasoline and air become provided with mist into the intake passage passes between the carburetor and the engine cylinder, the connecting portion of the intake pipe fitting A pipe intake rubber member , wherein a plurality of recesses are provided at substantially equal intervals along the circumferential direction on an inner peripheral surface that is continuous with at least one of the fitting portions .   2. The rubber member for pipe intake according to claim 1, wherein the rubber material is acrylonitrile butadiene rubber (NBR) or hydrogenated acrylonitrile butadiene rubber (hydrogenated NBR). 3. The pipe intake rubber member according to claim 1, wherein a core material along the axial direction is embedded inside.

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