JPS645080Y2 - - Google Patents

Description

[Detailed Description of the Invention] A. Technical Field This invention relates to a carburetor installed in an automobile engine, and particularly relates to a carburetor for an engine equipped with a supercharger.

B. Prior art In order to improve the engine efficiency of automobile engines, some use a supercharger to supply pressurized air, but in particular, those with a supercharger placed upstream of the carburetor The pressure in the intake passage of the carburetor during fuel supply becomes higher than atmospheric pressure, and fuel and pressurized air leak to the outside of the carburetor through gaps in the bearings of the choke shaft and throttle shaft, and are supplied to the engine. There were problems in that the air-fuel ratio of the air-fuel mixture was changed, and exhaust gas performance and supercharging efficiency were deteriorated.

Japanese Patent Application Laid-Open No. 56-6052 has been proposed as a solution to the above problems, but its structure is such that an annular rubber sheet is installed in the bearing part of the throttle shaft and is in close contact with the throttle shaft at all times. Pressurized air downstream of the supercharger is introduced into the outer surface of the rubber sheet.

C. Problems with the prior art In the above-mentioned carburetor, during supercharging, pressurized air is applied to the outer surface of the rubber sheet to forcefully press the inner surface of the rubber sheet against the outer peripheral surface of the throttle shaft, thereby preventing fuel leakage. It is intended to prevent

However, with this configuration, if the inner diameter of the rubber sheet is smaller than the outer diameter of the throttle shaft in the free state, it is somewhat effective in preventing fuel leakage during supercharging. Because it is always in close contact with the throttle shaft and does not move, the sliding resistance when the throttle shaft rotates is extremely large, causing the throttle to return poorly, and the rubber sheet is likely to wear out, resulting in a decrease in sealing force. In addition, it required a bypass passage to introduce pressurized intake air to the outer surface of the rubber sheet, which caused practical problems such as a complicated structure.

D. Purpose of the invention In view of the above-mentioned problems, this invention is designed to fill gaps in the bearings of the choke shaft, throttle shaft, etc. that communicate the intake passage of the carburetor with the outside world without forcibly sealing them during non-supercharging. By performing a forced seal using pressurized air only during supercharging, each shaft operates smoothly during supercharging and non-supercharging, and reliably prevents fuel and pressurized air from leaking during supercharging. The purpose of the present invention is to provide a carburetor for a supercharged engine.

E. Structure of the invention In order to achieve this object, this invention disposes a compressor of a supercharger that supplies pressurized air in the middle of an intake passage that communicates between the engine and the air cleaner, and connects the compressor and the engine. In a configuration in which a supercharged engine carburetor for controlling the supply of air-fuel mixture to the engine is disposed between them, a thin-walled part extending in the outer circumferential direction from one end of the cylindrical base to the entire circumference of the cylindrical base. Lip type pressure receiving part 1
A check valve of the carburetor is provided with an elastic member 11 having a pressure of 1a, and a boost pressure is provided at a portion thereof;
Notch groove 1 of a specified width on the shaft of the throttle valve
4a, and the elastic member 1 is inserted into the cutout groove 14a.
A sheet member press-fit hole 21 having a diameter larger than the diameter of the bearing hole 20 is provided coaxially with the bearing hole 20 provided in the carburetor main body 1, into which the base of
A cylindrical seat member 22 having a seat surface 22a at one end is press-fitted, and one surface of the lip-shaped pressure receiving portion 11a faces the seat surface 22a so as to be pressed against the seat surface 22a during supercharging. That is.

F. Example of the invention Next, an example of the invention will be described based on the drawings.

FIG. 1 is an explanatory diagram of a carburetor for a supercharged engine showing an embodiment of this invention. A compressor 3 for supplying pressurized air is installed in an intake passage connecting an air cleaner 2 and the carburetor body 1 on the upstream side of the carburetor body 1. A turbine 5 connected to a compressor 3 by a common shaft 4 is connected to an engine 6.
It is installed in an exhaust passage connecting the exhaust pipe 7b and the exhaust muffler 8. The compressor 3, shaft 4, and turbine 5 constitute a supercharger 9.
The downstream side of the carburetor body 1 is the intake pipe 7a of the engine 6.
is connected to.

A chiyoke valve 10 is disposed in the upper intake passage of the carburetor body 1, and the chiyoke valve 10 is fixed to a chiyoke shaft 12 provided with an elastic member 11' for sealing by known fixing means such as screws. A throttle valve 13 is disposed in the lower intake passage of the carburetor body 1, and the throttle valve 13 is fixed to a throttle shaft 14 equipped with an elastic member 11 for sealing by a known fixing means such as a screw. has been done.

A large bench lily 15 is formed in the carburetor body 1, and a small bench lily 16 is fixed to the carburetor body 1 upstream thereof. A main nozzle 17 is opened in the small bench lily 16, and the upstream side of the main nozzle 17 communicates with a float chamber 19 via a main jet 18 and the like.

Next, details of the seal structure will be explained with reference to FIG. However, since the basic seal structure is the same for both the throttle shaft and the throttle shaft, the seal structure for the throttle shaft will be treated as a representative example here.

A notch groove 14a of a predetermined width is formed in the throttle shaft 14 coaxially with the throttle shaft 14, and the notch groove 14a has a cylindrical base and a conical thin lip at the end. An elastic member 11 forming a shaped pressure receiving part 11a and having a rib 11b formed all around the peripheral edge on the sealing surface side.
is inserted. A sheet member press-fit hole 21 is formed in the carburetor main body 1 coaxially with the bearing hole 20 of the throttle shaft 14, and the press-fit hole 21 has a cylindrical shape, and the elastic member 11 is attached to one end of the press-fit hole 21. Seat surface 22 that performs a sealing action with
The sheet member 22 having a diameter of 1.a is connected to the sheet surface 22a and the rib 11b of the elastic member 11 during supercharging.
Each member is press-fitted and fixed with defined axial dimensions to ensure reliable contact.

In the description of this embodiment, a so-called turbocharger is shown as a supercharger installed upstream of the carburetor main body, which operates a compressor using engine exhaust pressure to perform supercharging, but other turbochargers may also be used. The same applies to supply means such as superchargers.

Next, the operation of this invention will be explained.

As the rotation of the engine 6 increases and the exhaust pressure increases, the turbine 5 of the supercharger 9 rotates, and the compressor 3 connected to the turbine 5 through a common shaft 4 rotates. The air taken in from the air cleaner 2 is pressurized by the rotation of the compressor 3 and supplied to the engine 6 via the carburetor main body 1 and the intake pipe 7a. In other words, the engine efficiency is improved by increasing the air filling efficiency. .

At this time, the internal intake passage of the carburetor body 1 is under a pressure state higher than atmospheric pressure due to the pressurized air.
Among the fuel sucked out from the main nozzle 17 via the main jet 18 and the like from the float chamber 19, the fuel flowing along the inner wall of the carburetor main body 1 and the fuel adhering to each shaft are transferred to the shafts 12, 14 and the bearing holes 20, 20'. Trying to be pushed out into the outside world through the gap between them. However, at this time, the pressurized air
By acting on the lip-shaped pressure receiving parts 11a, 11a' of the lip-shaped pressure receiving parts 11a, 11' and forcibly pressing one surface of the lip-shaped pressure receiving parts 11a, 11a' against the sheet members 22, 22', leakage of fuel to the outside world is completely prevented. is prevented. Moreover, the sealing state at this time is that of the ribs 11b and 11 provided on the lip-shaped pressure receiving parts 11a and 11a'.
Since it is a line seal by b', each shaft 1
The sliding resistance during the 2nd and 14th rotations is small, and there is no large difference in shaft rotational torque between supercharging and non-supercharging. Furthermore, the lip-shaped pressure receiving portions 11a, 11a' of the elastic members 11, 11' and the sheet members 22, 2
By defining the axial dimensions of each member, there is a nearly non-contact sealing effect (labyrinth effect), which prevents foreign matter from entering from the outside world, and the lip portion facing the seat surface. Since it has a thin wall, it has the advantage that it can be reliably deformed and pressed against the seat surface to perform forced sealing even when the boost pressure is low.

Effects of the invention As described above, according to this invention, an elastic member 11 having a thin lip-shaped pressure receiving part 11a extending in the outer circumferential direction from one end of a cylindrical base over the entire circumference is provided, and the base of the elastic member 11 is connected to the The lip-shaped pressure receiving part 11a is fitted into a notch groove 14a provided in a shaft such as the like, and the lip-shaped pressure receiving part 11a corresponds to one end of a sheet member press-fitted into the carburetor body. Since forced sealing is performed, the lip type pressure receiving part 11 is closed during supercharging.
Since the force with which a presses one end of the sheet member is stronger and more reliable than when no supercharging is performed, gaps in the bearings of the choke shaft and throttle shaft can be reliably sealed during supercharging. In addition, since the sealing structure of each shaft presses against the side surface of the sheet member, the frictional force generated by the holding force is small, and the shaft is easy to slide, so the sliding resistance is small, and the sliding resistance is small, and the sealing structure presses against the side surface of the sheet member. There is no large difference in rotational torque, allowing smooth operation and preventing failure of the shaft to return.In addition, since there is no forced sealing at all times, there is little deterioration of the sealing member, and during supercharging, the fuel and pressurization can be reliably removed. This has a great practical effect of preventing air leakage.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of a carburetor for a supercharged engine, which is an embodiment of the present invention. FIG. 2 is an explanatory diagram of the main parts of the present invention in FIG. 1. 1... Carburetor body, 2... Air cleaner, 3...
...Compressor, 9...Supercharger, 11, 11'...
...Elastic member, 11a, 11a'...Rip type pressure receiving part, 12...Chewy shaft, 14...Throttle shaft, 22...Sheet member, 22a...
Seat surface.

Claims (1)

[Scope of utility model registration request] A compressor for a supercharger that supplies pressurized air is disposed in the middle of an intake passage that communicates between the engine and the air cleaner, and a supercharger that controls the supply of air-fuel mixture to the engine is installed between the compressor and the engine. In a configuration in which a carburetor for a fed engine is disposed, an elastic member 11 is provided having a thin lip-shaped pressure receiving portion 11a extending in the outer circumferential direction from one end of a cylindrical base to the entire circumference of the cylindrical base. A notch groove 14a of a predetermined width is formed in the shaft of the choke valve and throttle valve of the carburetor, which are provided in the portion to which the supply pressure is applied, and the base of the elastic member 11 is fitted into the notch groove 14a, and the carburetor main body is A sheet member press-fit hole 21 having a diameter larger than the diameter of the bearing hole 20 is provided coaxially with the bearing hole 20 provided in 1, and a cylindrical sheet member 22 having a seat surface 22a at one end is press-fitted into the press-fit hole 21, A carburetor for a supercharged engine, characterized in that one surface of the lip-shaped pressure receiving part 11a faces the seat surface 22a so as to be pressed against the seat surface 22a during supercharging.