JPH0245651A - Motor-driven type starting fuel pump for portable working machine - Google Patents

Abstract

PURPOSE:To surely send fuel into a carburetor by always transferring a starting fuel pump under the liquid level of fuel even if a fuel tank tilts, by accommodating the starting fuel pump and an electric motor in shiftable ways inside the fuel tank. CONSTITUTION:A starting fuel pump E is accommodated in shiftable ways inside a fuel tank 32 joined with the bottom part of an engine body. The starting fuel pump E is constituted by joining a pump 74 onto the shaft of an electric motor 76 consisting of a field coil 67 and an armature 75. The discharge port of the starting fuel pump E is connected with a carburetor by a fuel pipe 29. The fuel pipe 29 is pulled outside, penetrating through a sealing member 63 installed onto the upper wall of the fuel tank 32. A lead wire 30 led out from the electric motor 76 is pulled outside from the sealing member 61 for a three- way pipe 62 through an outlet pipe 64a and the inside of the fuel pipe 29 and connected with a power source battery.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electric starter fuel pump for use in a small internal combustion engine of a portable working machine.

[Prior Art] In automobiles, fixing an electric fuel pump inside the fuel tank isolates the electric motor from the heat surrounding the engine, cools the electric motor with fuel, and prevents the pump from running dry. It has advantages such as:

Portable working machines are now equipped with an internal combustion engine equipped with a starting motor driven by a battery MS, and along with this, an electric starting fuel pump (primer pump) that generates a rich mixture for starting has become necessary. Recruitment is now possible. However, since the attitude of the portable work machine changes, fuel must be sucked in even if the fuel tank is tilted.

[Problems to be Solved by the Invention] Therefore, an object of the present invention is to provide a portable working machine in which the starting fuel pump is always moved below the fuel level even if the fuel tank is tilted, and the fuel is reliably sent to the carburetor. An object of the present invention is to provide an electric starting fuel pump.

[@Means for Solving the Problem] In order to achieve the above object, the configuration of the present invention movably accommodates a pump for pumping starting fuel to a carburetor and an electric motor coupled thereto inside a fuel tank, The lead wire of the electric motor is connected to a power source outside the fuel tank through the inside of the fuel pipe.

[Function] The fuel pipe 29 extending from the carburetor 22 is connected to the seal member 63.
It is inserted into the inside of the fuel tank 32 through the cylindrical end, and an electric starting fuel pump E is connected to this end.

The starting fuel pump E moves along the bottom of the fuel tank 32 in accordance with the inclination of the fuel tank 32 and is always below the fuel level, so that the starting fuel is reliably sent to the carburetor 22.

Since the lead wire 30 from the electric motor 76 passes through the inside of the fuel pipe 29 and is led out to the outside of the fuel tank 32,
The sealing structure of the fuel tank 32 is simplified, the electric starting fuel pump E can be easily moved, and the guide wheel 30I
There is no damage caused by sliding friction.

[Embodiments of the Invention] FIG. 1 is a side view showing a schematic configuration of an internal combustion engine for a portable working machine equipped with an electric starter fuel pump according to the present invention. In an internal combustion engine 11123 mounted on a portable working machine, an air cleaner 21 and a carburetor 22 are connected to one side of the engine body, and a muffler 24 is connected to the other side.

The crankshaft 27 is connected to the starter motor 25 via a gear mechanism 26.
It is configured so that it can be rotationally coupled with. A fuel tank 32 is coupled to the bottom of the engine body, and a starter fuel pump E according to the present invention is movably housed inside the fuel tank 32. The discharge port of the starting fuel pump E is connected to the carburetor 22 by a fuel pipe 29. The conductor 30 of the electric motor 76 is led out of the fuel tank 32 through the inside of the fuel pipe 29, and the connector 30a at the end of the conductor 1130 is connected to an m-source battery (not shown).

As shown in FIG. 2, the carburetor 22 includes a diaphragm-type fuel pump A, a fuel supply mechanism B that holds the fuel sent to the intake passage 11 of the carburetor 22 at a constant pressure, and a fuel supply mechanism B that is switched off at and after starting the engine. The switching valve C includes a switching valve C and an electromagnetic actuator D driving the switching valve C. The starting fuel pump E is driven when the engine is started, and supplies fuel to the fuel supply mechanism B. After the engine is started, fuel in the fuel tank 32 is supplied to the fuel supply mechanism B by a diaphragm-type fuel pump A driven by pulsating pressure in the crank chamber of the engine.

The carburetor 22 has a cylindrical portion 2 extending in the vertical direction formed in the center of a main body 18 having an intake passage 11 extending in the horizontal direction.
This upper end may be opened and closed by the lid 12. A rotary type comparison valve 8 having a throttle hole 8a in the cylindrical portion 2 is fitted so as to be rotatable and swingable in the axial direction. The shaft portion 14 extending upward from the throttle valve 8! 12 , and a follower 16 is supported by a lever 15 coupled to the upper end of the shaft portion 14 . Lid 1
2 and the throttle valve 8, the spring 1 surrounds the shaft portion 14;
3 forces the follower 16 into engagement with the cam surface 17 provided on the lid 12, and as the lever 15 is rotated, the valve 8 moves in the axial direction. At this time, the rod valve 3 integrated with the adjustment bolt 14a screwed into the screw hole of the shaft portion 14 also moves in the axial direction.

A spring 5 surrounding the rod valve 3 inside the threaded hole is attached to the shaft portion 1.
To facilitate adjustment of the pupil of the rod valve 3 relative to 4.

A fuel supply pipe 7 whose opening degree of the nozzle hole 6 is adjusted by the rod valve 3 is fixedly supported on the bottom wall of the main body 18 . The fuel supply pipe 7 is communicated with the metering chamber 38 via a fuel jet 46 and a switching valve C1 passage 43.

The fuel pump A has a main body 70 coupled to the lower surface of the main body 18 with a diaphragm 53 in between, and has a pulsating pressure introducing chamber 54 on the upper side and a pump chamber 55 on the lower side. The pulsating pressure introduction chamber 54 has an inlet 59 connected to, for example, a crank chamber of a two-stroke engine, and causes the diaphragm 53 to reciprocate up and down.

The pump chamber 55 includes a passage 51, a check valve 10, a filter 37,
It can communicate with a fuel tank 32 via a passage 31, a fuel pipe 29, and a starting fuel pump E. In addition, the pump chamber 55
can communicate with the metering chamber 38 via the check valve 4, the passage 52, and the fuel inlet valve 9.

A diaphragm 34 and a cover 28 are coupled to the lower surface of the main body 70, thereby defining a metering chamber 38 on the upper side and an atmospheric chamber 36 having an atmospheric air port 58 on the lower side.

A lever 41 is mounted inside the metering chamber 38 by a support shaft 40.
is supported. The left end of the lever 41 is abutted by a spring against a rivet 34a that connects the backing plate to the diaphragm 34, while the right end supports a poppet-type fuel inlet valve 9.

The electromagnetic actuator D includes an electromagnetic coil 73 fixed to the cover 28 and a plunger 73a. l! When the magnetic coil 73 is excited, the plunger 73a projects upward and abuts against the rivet 34a of the diaphragm 34, and the switching valve C is pushed up via the lever 41 against the force of the spring.

The switching valve C is constructed by disposing a valve body 39 in the valve chamber 42 in the middle of a passage connecting the metering chamber 38 and the fuel jet 46. The valve body 39 is in a normal position where it blocks the passage 43 from the passage 50 communicating with the fuel tank 32 and communicates with the fuel jet 46;
And the position is switched to a position communicating with the passage 50.

As shown in Figure 3.4, the starting fuel pump E is
A pump 74 is attached to the shaft of an electric l176 consisting of an armature 75 and an armature 75.
It is composed by combining. The field @67 of the electric motor 76 is housed inside a case 66, and this case 66 is connected to the housing 6.
4 is fitted. A sieve-shaped frame 71 is engaged with the outside of the pump 74, a cylindrical filter 69 is fitted onto the frame 71, and the frame 71 and the filter 69 are connected to the housing by a clip 72 consisting of a U-shaped band plate. 64.

A pair of longitudinal grooves 69a are provided on the outer peripheral surface of the filter 69, and a groove continuous with the grooves 69a and a groove 71b crossing the end surface of the flange 71a are also formed on the end flange 71a of the frame 71. The clip 72 is coupled, and the end claw piece 72a of the clip 72 is locked in the recess 68 of the housing 64.

A fuel pipe 29 made of vinyl or the like is fitted onto an outlet pipe 64a formed at the end of the housing 64, and is coupled with a tightening ring 65. The fuel pipe 29 passes through a seal member 63 made of a grommet attached to the upper wall of the fuel tank 32 and is drawn out of the fuel tank 32 . Three sides in the middle of fuel pipe 29! ! 62 is connected. The lead wire 30 from the electric motor 76 passes through the outlet pipe 64a1 and the inside of the fuel pipe 29, and is drawn out from the seal member 61 of the three-way pipe 62.

Before starting the engine, when the W1@coil 73a of the electromagnetic actuator D is excited, the plunger 73a is pushed up, the fuel inflow valve 9 is pulled down and opened by the lever 41, and the valve body 39 of the switching valve C is is pushed up, and the passage 43 and the passage 5o communicate with each other.

Next, when the starting fuel pump E is driven, the fuel in the fuel tank 32 passes through the filter 69 and the inside of the frame 71, is sucked into the pump 74, and is sucked into the inner cavity of the electric motor 76 and the outlet pipe 64.
a. The fuel is sent to the carburetor 22 via the fuel pipe 29. In the carburetor 22 , fuel is supplied to the metering chamber 38 through the passage 31 , filter 37 , check valve 10 , passage 51 , pump chamber 55 , check valve 4 , passage 52 , and fuel inlet valve 9 . Air in the metering chamber 38 and excess fuel are transferred to a passage 43, a valve chamber 42,
It is discharged to the fuel tank 32 via passage 50.

In this way, when the metering chamber 38 is filled with fuel, the starter motor 25 is driven.

Due to negative pressure in the intake passage 11 as the engine cranks, fuel in the metering chamber 38 is sucked into the intake passage 11 from the nozzle hole 6 of the fuel supply pipe 7 through the passage 43, the valve chamber 39, and the fuel jet 46. Mixed with intake air and supplied to the engine,
This allows the engine to start smoothly.

When the fuel in the metering chamber 38 becomes low, the fuel inlet valve 9 opens, and the diaphragm 53 of the fuel pump A, which is moved up and down by the pulsating pressure in the crank chamber, allows the fuel in the fuel tank 32 to flow into the starting fuel pump E for one hour. The fuel is sucked into the pump chamber 55 through the pipe 29, passage 31, filter 37, check valve 101 passage 51, and then roughly supplied to the metering chamber 38 through the check valve 4, passage 52, and fuel inlet valve 9.

With respect to the inclination of the fuel tank 32, the starting fuel pump E is only connected to the fuel pipe 29, so it can freely move to the lowest part of the fuel tank 32. Therefore, the starting fuel pump E is always below the fuel level and does not run idly, and reliably delivers fuel to the carburetor 22.

Since the lead wire 130 of the electric motor 76 is drawn out to the outside of the fuel tank 32 through the inside of the fuel pipe 29, the lead wire 30 may become entangled with the fuel pipe 29 and prevent the movement of the starting fuel pump E, or the lead wire 130 may slide. There is no risk of wear and tear or short circuit.

Since the conductor 3o and the fuel pipe 29 are led out to the outside of the fuel tank 32 through the common seal member 63, it is easier to install them in the fuel tank 32 than in a case where the fuel pipe 29 and the lead 1130 are led out to the outside of the fuel tank 32 separately. There are fewer holes, which reduces the strength of the fuel tank and simplifies the seal structure to prevent fuel leakage.

[Effects of the Invention] As described above, the present invention movably accommodates a pump for pressure-feeding starting fuel to a carburetor inside a fuel tank and an electric motor connected thereto, and connects the lead wire of the electric motor to the inside of a fuel pipe. It is connected to the external power source of the fuel tank through the
Since the electric motor and pump are integrated and connected to the end of the fuel pipe, they can move freely depending on the inclination of the fuel tank, and are always below the fuel level, ensuring that fuel is delivered to the carburetor. send.

The lead wire from the electric motor is routed inside the fuel pipe and moves effortlessly together with the fuel pipe, thereby preventing damage due to sliding friction.

Since the part of the conductor that is drawn out from the fuel tank is placed inside the fuel pipe, the number of sealing members installed in the fuel tank is reduced, compared to when the conductor and fuel pipe are drawn out separately from the fuel tank. , simple in configuration and easy to assemble.

[Brief explanation of the drawing]

FIG. 1 is a side view showing a schematic configuration of an internal combustion engine equipped with an electric starting fuel pump for a portable working machine according to the present invention, and FIG. 2 is a side sectional view of a carburetor equipped with the same electric starting fuel pump.
FIG. 3 is a side sectional view of the electric starter fuel pump, and FIG. 4 is an exploded perspective view of the electric starter fuel pump. E: Electric starter fuel pump 22: Carburetor 29: Fuel pipe 30: Conductor 32: Fuel tank 69; Filter 74: Pump 76: Electric motor Fig. 2

Claims (2)

[Claims] (1) A pump for pumping starting fuel to the carburetor and an electric motor connected to the pump were movably housed inside the fuel tank, and the lead wire of the electric motor was connected to a power source outside the fuel tank through the inside of the fuel pipe. An electric starting fuel pump for a portable work machine, which is characterized by: (2) Claims in which the electric motor and starting fuel pump are housed inside a housing surrounded by a fuel filter (
1) The electric starting fuel pump for the portable working machine according to item 1).