JP2519899Y2 - Diaphragm vaporizer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a diaphragm type vaporizer, and more particularly to means for preventing a temperature rise thereof.

[Conventional technology]

Generally, in an engine such as a brush cutter, the carburetor is cooled by the heat of vaporization of the fuel flowing inside the engine when the engine is operating, but there is no fuel flow when cooling down after the engine is stopped. Is transmitted to the vaporizer and the temperature of the vaporizer rises.

So, as one of the conventional measures, for example
As described in Japanese Patent No. 186760 and Japanese Utility Model Laid-Open No. 61-198555, a heat insulator (insulator) is provided between the cylinder and the carburetor so that heat is not transferred from the cylinder to the carburetor during cooling down after the engine is stopped. Is provided.

FIG. 2 shows the former conventional example, in which the cylinder 30
A heat insulating material 31 is interposed between and a vaporizer 33 made of synthetic resin. In this conventional example, a temperature adjusting metal member 32 is further interposed between the heat insulating material 31 and the vaporizer 33 in order to enhance the heat radiation effect.

[Problems to be solved by the device]

In the prior art described in the above publication, since the temperature rise prevention measure of the carburetor is provided at a high temperature portion, it is necessary to make the heat insulating material very thick, and as a result, the amount of overhang of the entire carburetor is large. As a result, the durability of the carburetor is deteriorated, and the carburetor is protruded from the external appearance of the engine, so that it is restricted in size.

On the other hand, when the carburetor rises to a certain temperature (about 60 ° C), the fuel around the intake check valve and the discharge check valve arranged before and after the pump diaphragm that constitutes the fuel delivery pump evaporates, and both check valves get wet. It is conceivable that if the fuel is lost, the sealability is impaired, the check function is lost, the fuel feed pump and the priming pump do not operate, and the engine cannot start.

In particular, it is expected that the situation will worsen when the temperature rises due to the high temperature atmosphere in summer and direct sunlight.

Therefore, the purpose of the present invention is not to provide a heat insulating material between the cylinder and the carburetor at a high temperature place as in the conventional case, but to lower the temperature to some extent, that is, to vaporize a part away from the cylinder. The object of the above prior art is to be solved by a new idea such as that a heat insulating material is interposed between the main body of the vessel and the fuel feed pump section to separate the two.

[Means for solving the problem]

In order to achieve the above object, the diaphragm type carburetor according to the present invention has a fuel supply passage communicating with a fuel inlet and connected to a discharge check valve through a suction check valve, a fuel delivery pump including a pump diaphragm and an engine impulse passage. A part of a carburetor that has a fuel feed pump part and whose fuel supply passage from the discharge check valve communicates with a methane ring chamber formed in the carburetor body part, where the temperature has dropped to some extent away from the engine cylinder The fuel supply pump is disposed in the fuel supply pump, the fuel supply pump is structurally separated from the carburetor body, and the discharge check connecting the carburetor body and the fuel supply pump is performed. A heat insulating material is provided at a position of a fuel supply passage leading from the valve to the methane ring chamber, and the fuel feed pump section is also insulated from the carburetor main body section. Ri apart, characterized in that assembled on the carburetor body portion.

Further, in the above-mentioned configuration, the heat radiation fins are provided so as to project from the outer surface of the fuel delivery pump section according to claim 1 which is separated from the carburetor main body section by the heat insulating material.

[Action]

In the above structure, the heat of the cylinder is prevented from being transmitted to the fuel delivery pump through the carburetor main body during cooling down after the engine is stopped. Further, the heat insulating effect can be reliably obtained because the temperature of the portion where the heat insulating material is arranged is far from the cylinder and the temperature is lowered to some extent. Further, the heat radiation fins release the heat of the fuel feed pump unit to further prevent the temperature rise of the fuel feed pump unit.

〔Example〕

FIG. 1 is a sectional view of a diaphragm type carburetor according to an embodiment of the present invention. As shown in the figure, the diaphragm type carburetor is composed of a carburetor main body portion C and a fuel feed pump portion P.

In FIG. 1, a heat insulating material 7 is interposed between the carburetor main body portion C and the fuel feed pump portion P. That is, the feature of this embodiment is that the temperature is lowered to some extent, that is, the cylinder (not shown), rather than the heat insulating material being interposed between the cylinder and the carburetor at the high temperature place as in the conventional case. However, the heat insulating material 7 is interposed between the carburetor main body portion C and the fuel feed pump portion P, which are located away from the paper surface (at a right angle to the paper surface), and the two are separated. As the heat insulating material 7, for example, a material having a relatively high rigidity such as bakelite is used, and it is fixed to the carburetor main body C by a bolt from the fuel feed pump portion P side (not shown).

With the above, the cylinder heat is effectively prevented from being transferred to the fuel feed pump section P through the carburetor main body section C at the time of cooling down after the engine is stopped.

Although not shown, when the heat radiation fin 9 is provided in the fuel feed pump unit P and the heat insulating material 7 is interposed between the fuel feed pump unit P and the carburetor main body unit C, the fuel feed unit A further effect of preventing the temperature rise of the feed pump unit P can be obtained.

Here, the structure of the starting device for the diaphragm type carburetor will be described with reference to FIG. 1. In the fuel feed pump section P, the fuel feed passage 8 communicating with the fuel inlet A of the fuel feed pump section P has a suction check valve 5 and a fuel feed pump. The fuel cell is communicated with the fuel supply passage 8A through the pump diaphragm 2 and the discharge check valve 6 that form part 1. A part of the fuel supply passage 8A is formed so as to penetrate the heat insulating material 7 and communicates with the supply passage formed in the carburetor main body portion C.

A priming pump 4 for supplying fuel into the metering chamber 15 at the time of starting the engine is arranged at a position facing the pump diaphragm 2. Further, the pump diaphragm chamber is communicated with an engine impulse passage 3 for introducing an operating pressure having an engine pulsation for operating the pump diaphragm 2, for example, a crank chamber pressure in a two-cycle engine. The feed pump 1 is configured.

A needle valve 10 is provided on the downstream side of the fuel supply passage 8A in the carburetor main body C.
The fuel supply passage 8A communicates with the inside of the metering chamber 15 defined by the main diaphragm 16 via 10.

An operating rod 13 pivotally supported by the hinge pin 11 is provided in the metering chamber 15, one end of which is in contact with the main diaphragm 16 and the other end of which is connected to the needle valve 10. The operating rod 13 is provided with a spring 12 for urging the needle valve 10 in the closing direction. The lower surface of the main diaphragm 16 faces the atmosphere side through the opening 14a of the cover 14. The projection of the operating rod 17A which is operated by the operation of the tickler lever 17 faces the opening 14a. On the other hand, on the opposite (downstream) side of the needle valve 10 of the metering chamber 15, a fuel supply passage connected to the intake port of the engine in a direction perpendicular to the plane of the drawing through a passage formed in the tip of the adjusting screw 19 and the jet needle 20. 8B are formed to communicate with each other. Further, the metering chamber 15 communicates with the overflow pipe 18 via an overflow valve 18A that opens and closes by operating a tickler lever 17 provided on the passage 8c. In addition, 21 is a body cap, 22 is a throttle valve, 23 is a throttle cable, and 24 is a slow stop screw.

Next, the operation at the time of starting the engine will be described. It is necessary to fill the metering chamber 15 with fuel at the time of starting the engine. So tickler lever
The needle valve 10 is manually opened by operating the valve 17, and at the same time, the air vent and fuel overflow valve 18A is opened. In this state, the priming pump 4 is pushed or pinched to operate to change the internal volume of the pump and suction / discharge check valves 5 and 6 provided on a part of the surface of the pump diaphragm 2 and a spring 5a for strengthening the sealing property. , 6a
The fuel is sucked from a fuel tank (not shown) by the function of the fuel supply passages 8 and 8A, and the metering chamber 15
Pump inward. Then, it is confirmed by the fuel flowing out of the overflow pipe 18 that the inside of the metering chamber 15 is full of fuel, and at the same time, the pump operation is stopped and the tickler lever 17 is released. Next, when the engine recoil starter (not shown) is pulled to rotate the engine, fuel is supplied through the venturi into the engine and starts.

Thus, in the above-described embodiment, the temperature rise of the fuel feed pump unit P forming the carburetor is prevented,
It is possible to prevent fuel vaporization in the vicinity of the intake check valve 5 and the discharge check valve 6 arranged before and after the pump diaphragm 2 and to always keep the check valves 5 and 6 moist, thereby ensuring the sealing property, that is, the check function. As a result, it is possible to avoid a situation in which the fuel delivery pump 1 and the priming pump 4 cannot be started due to inoperability.

[Effect of device]

According to the present invention described above, the heat insulating material is interposed between the carburetor main body portion and the fuel feed pump portion at the portion where the temperature is relatively lowered away from the cylinder, and thus the two are separated. Alternatively, or by providing the radiation fins in the fuel feed pump unit, it is possible to effectively prevent the temperature rise of the fuel feed pump unit and improve the startability.

Further, when a heat insulating material and a radiation fin are combined, a further effect can be expected.

[Brief description of drawings]

FIG. 1 is a sectional view of a diaphragm type vaporizer according to an embodiment of the present invention. FIG. 2 is an explanatory diagram of a conventional technique. 1 ... Fuel feeding pump, 4 ... Priming pump, 5 ... Suction check valve, 6 ... Discharge check valve, 7 ... Insulation material, 9 ...
Radiating fin, 10 ... Needle valve, 15 ... Metering chamber, C ... Vaporizer main body section, P ... Fuel delivery pump section.

Claims (2)

(57) [Scope of utility model registration request] 1. A fuel feed pump portion, wherein a fuel feed passage communicating with a fuel inlet is connected to a discharge check valve via a fuel feed pump including an intake check valve, a pump diaphragm and an engine impulse passage. In a carburetor in which the fuel supply passage from the discharge check valve communicates with a methane ring chamber formed in the carburetor main body part, the fuel feed pump is arranged at a portion where the temperature has dropped to a certain extent away from the cylinder of the engine. A fuel supply passage that structurally separates the fuel feed pump from the carburetor body, and that connects the carburetor body and the fuel feed pump from the discharge check valve to the methane ring chamber. A heat insulating material is interposed at the position of and the fuel feed pump part is also adiabatically separated from the carburetor main body part and assembled to the carburetor main body part. Diaphragm type carburetor. 2. The diaphragm type carburetor according to claim 1, wherein a radiating fin is projected from the outer surface of the fuel feed pump section according to claim 1, which is separated from the carburetor main body section by a heat insulating material.