JP2648671B2 - Electric starting fuel pump for portable work equipment - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an electric starting fuel pump used for a small internal combustion engine of a portable working machine.

2. Description of the Related Art In an automobile, fixing an electric fuel pump inside a fuel tank involves isolating the electric motor from heat around the engine, cooling the electric motor with fuel, and preventing idling of the pump. There are advantages such as.

An internal combustion engine equipped with a starter motor driven by a battery power source has also been mounted on a portable work machine. Accordingly, an electric starter fuel pump (primer pump) that generates a rich air-fuel mixture for starting has been installed. Recruitment became possible. However, since the attitude of the body changes in the portable work machine, fuel must be sucked even when the fuel tank is inclined.

[Problems to be Solved by the Invention] Therefore, an object of the present invention is to provide a portable work machine in which the starting fuel pump always moves below the fuel level even when the fuel tank is tilted, and the fuel is reliably sent to the vaporizer. It is to provide an electric starting fuel pump.

Means for Solving the Problems To achieve the above object, according to the configuration of the present invention, a starting fuel pump for pumping starting fuel to a carburetor and an electric motor coupled to the starting fuel pump have an outer peripheral portion provided with a fuel filter. The housing is housed inside a housing surrounded by a circle, and the housing is movably housed inside the fuel tank.

[Operation] A fuel pipe 29 extending from the carburetor 22 is inserted into the inside of the fuel tank 32 through a seal member 63, and an electric start fuel pump E is connected to an end of the fuel pipe 29. The starting fuel pump E moves along the bottom of the fuel tank 32 according to 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 motor 76 is drawn out of the fuel tank 32 through the inside of the fuel pipe 29, the sealing structure of the fuel tank 32 is simplified, and the movement of the electric start fuel pump E is easy. Also, the conductive wire 30 is not damaged by sliding friction.

[Embodiment 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 starting fuel pump according to the present invention.
An internal combustion engine 23 mounted on a portable working machine has an engine body connected to an air purifier and a carburetor 22 on one side, and a muffler 24 connected to the other side. The crankshaft 27 is configured to be rotatable with the starting motor 25 via a gear mechanism 26. A fuel tank 32 is connected to the bottom of the engine body, and a starting fuel pump E according to the present invention is movably accommodated 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 lead 30 of the electric motor 76 for driving the starting fuel pump E is
It is drawn out of the fuel tank 32 through the inside of the fuel pipe 29, and the connector 30a at the end of the conductor 30 is connected to a power supply battery (not shown).

As shown in FIG. 2, the vaporizer 22 is a membrane type fuel pump A
A fuel supply mechanism B for holding the fuel sent to the intake passage 11 of the carburetor 22 at a constant pressure, a switching valve C that switches between when the engine starts and after the engine starts, and an electromagnetic actuator D that drives the switching valve C
And 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, the fuel in the fuel tank 32 is supplied to the fuel supply mechanism B by the membrane type fuel pump A driven by the pulsating pressure of the crank chamber of the engine.

The carburetor 22 has a body 18 having a laterally extending intake passage 11.
A cylindrical portion 2 extending in the vertical direction is formed at the center of the cylindrical portion, and an upper end portion of the cylindrical portion 2 is closed by a lid 12. A rotary throttle valve 8 having a slot hole 8a in the cylindrical portion 2 is fitted so as to be rotatable and slidable in the axial direction. A shaft portion 14 extending upward from the throttle valve 8 is supported by the lid 12, and a follower 16 is supported by a lever 15 coupled to the upper end of the shaft portion 14. The follower 16 is urged into engagement with the cam surface 17 provided on the lid 12 by the force of the spring 13 surrounding the shaft portion 14 between the lid 12 and the throttle valve 8, and the lever 15 is rotated. The throttle 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 together. The spring 5 surrounding the rod valve 3 inside the screw hole is a rod valve 3
Facilitates the adjustment of the position.

Fuel supply pipe 7 whose opening degree of injection hole 6 is adjusted by rod valve 3
Is fixedly supported on the bottom wall of the main body 18. The fuel supply pipe 7 passes through the fuel jet 46, the switching valve C, and the passage 43, and passes through the constant pressure fuel chamber 38.
Is communicated to.

In the fuel pump A, a pulsating pressure introducing chamber 54 is formed on the upper side and a pump chamber 55 is formed on the lower side by connecting the main body 70 to the lower surface of the main body 18 with the membrane 53 interposed therebetween. The pulsating pressure introduction chamber 54 is connected at an inlet 59 to, for example, a crank chamber of a two-cycle engine, and reciprocates the membrane 53 up and down. The pump chamber 55 can communicate with the fuel tank 32 via the passage 51, the check valve 10, the filter 37, the passage 31, the fuel pipe 29, and the starting fuel pump E. The pump chamber 55 can communicate with the constant-pressure fuel chamber 38 via the check valve 4, the passage 52, and the fuel inflow valve 9.

The membrane 34 and the cover 28 are coupled to the lower surface of the main body 70, and the membrane 34 divides the constant pressure fuel chamber 38 on the upper side and the atmosphere chamber 36 having the atmosphere port 58 on the lower side. A spindle inside the constant pressure fuel chamber 38
The lever 41 is supported by 40. The left end of the lever 41 is abutted by a spring on a rivet 34a for connecting the caul plate to the membrane 34, while the right end is engaged with the poppet type fuel inflow valve 9.

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

The switching valve C is configured by disposing a valve element 39 in a valve chamber 42 in the middle of a passage connecting the constant pressure fuel chamber 38 and the fuel jet 46. Valve 39
Switches between a normal position where the passage 43 is cut off from the passage 50 communicating with the fuel tank 32 and the fuel jet 46, and a position where the passage 43 is cut off from the fuel jet 46 and communicates with the passage 50.

As shown in FIGS. 3 and 4, the starting fuel pump E is configured by connecting a pump 74 to a shaft of an electric motor 76 including a field 67 and an armature 75. The field 67 of the electric motor 76 is housed inside a case 66, which is fitted into the housing 64. Pump 74
A basket-shaped frame 71 is engaged with the outside of the housing, a cylindrical filter 69 is fitted on the frame 71, and the frame 71 and the filter 69 are attached to the housing 64 by a clip 72 formed of a U-shaped curved strip. Locked.

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

A fuel pipe 29 such as vinyl is externally fitted to an outlet pipe 64a formed at an end of the housing 64, and is fastened by a fastening ring 65. The fuel pipe 29 is drawn out of the fuel tank 32 through a seal member 63 formed of a grommet mounted on the upper wall of the fuel tank 32. A three-way pipe 62 is connected in the middle of the fuel pipe 29. The lead wire 30 from the motor 76 is an outlet pipe 64a,
Through the inside of the fuel pipe 29, it is pulled out from the seal member 61 of the three-way pipe 62 to the outside.

If the electromagnetic coil 73a of the electromagnetic actuator D is excited before the engine is started, 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 pushed up. The passage 43 and the passage 50 communicate with each other.

Next, when the starting fuel pump E is driven, the fuel tank 32
The fuel is sucked into the pump 74 through the filter 69 and the inside of the frame 71, and the inner space of the electric motor 76, the outlet pipe 64a, the fuel pipe 2
After passing through 9, it is sent to vaporizer 22. In the carburetor 22, the fuel is supplied to the constant-pressure fuel chamber through the passage 31, the filter 37, the check valve 10, the passage 51, the pump chamber 55, the check valve 4, the passage 52, and the fuel inflow valve 9. The air in the constant-pressure fuel chamber 38 and excess fuel flow through the passage 43,
The fuel is discharged to the fuel tank 32 through the valve chamber 42 and the passage 50.

As described above, when the constant pressure fuel chamber 38 is filled with fuel, the starting motor 25 is driven. Due to the negative pressure in the intake passage 11 accompanying the cranking of the engine, the fuel in the constant pressure fuel chamber 38 passes through the passage 43, the valve chamber 42, and the fuel jet 46, and the fuel supply pipe 7
Is sucked into the intake passage 11 from the injection hole 6 and mixed with the intake air to be supplied to the engine, whereby the engine is started smoothly.

When the fuel in the constant pressure fuel chamber 38 becomes low, the fuel inflow valve 9 is opened, and the fuel in the fuel tank 32 is started by the membrane 53 of the fuel pump A which is moved up and down by the pulsating pressure of the crank chamber.
Gap, fuel pipe 29, passage 31, filter 37, check valve 1
0, it is sucked into the pump chamber 55 through the passage 51, and further supplied to the constant pressure fuel chamber 38 through the check valve 4, the passage 52, and the fuel inflow valve 9.

For the inclination of the fuel tank 32, the starting fuel pump E is freely connected to the lowest part of the fuel tank 32 because it is only connected to the fuel pipe 29. Accordingly, the starting fuel pump E is always below the liquid level of the fuel and does not run idle, and reliably sends the fuel to the carburetor 22. Since the lead wire 30 of the electric motor 76 is drawn out of the fuel tank 32 through the inside of the fuel pipe 29, the lead wire 30 is entangled with the fuel pipe 29 and hinders the movement of the starting fuel pump E, or the lead wire 30 slides. There is no danger of cutting due to wear or short circuit.

Since the conductor 30 and the fuel pipe 29 are drawn out of the fuel tank 32 through the common sealing member 63, the fuel pipe 29 and the conductor
The number of holes provided in the fuel tank 32 is smaller than that in which the fuel tank 30 is separately drawn out of the fuel tank 32, the reduction in strength of the fuel tank is suppressed, and the seal structure for preventing fuel leakage is simplified.

[Effect of the Invention] As described above, according to the present invention, a starting fuel pump for pumping starting fuel to a carburetor and an electric motor coupled to the starting fuel pump are housed in a housing whose outer peripheral portion is surrounded by a fuel filter. A portable work machine, wherein the housing is movably accommodated inside a fuel tank, wherein the motor and the pump are integrally formed and connected to an end of a fuel pipe. Therefore, the fuel tank moves freely according to the inclination of the fuel tank, and always moves below the liquid level of the fuel to reliably send the fuel to the vaporizer.

The lead wire from the electric motor is arranged inside the fuel pipe and moves smoothly and integrally with the fuel pipe, so that damage due to sliding friction is prevented.

Since the portion of the lead wire drawn out of the motor from the fuel tank to the outside is arranged inside the fuel pipe, the number of seal members provided in the fuel tank is reduced, and the lead wire and the fuel pipe are separately moved to the outside of the fuel tank. Compared with the case of pulling out, the configuration is simple and assembly is easy.

[Brief description of the drawings]

FIG. 1 is a side view showing a schematic configuration of an internal combustion engine having an electric starting fuel pump of a portable work machine according to the present invention, FIG. 2 is a side sectional view of a carburetor having the electric starting fuel pump,
FIG. 3 is a side sectional view of the electric starting fuel pump, and FIG. 4 is an exploded perspective view of the electric starting fuel pump. E: electric start fuel pump, 22: carburetor, 29: fuel pipe,
30: Lead wire, 32: Fuel tank, 69: Filter, 74: Pump, 76: Electric motor

Claims (1)

(57) [Claims] A starting fuel pump for pumping starting fuel to a carburetor and an electric motor coupled to the starting fuel pump are housed in a housing whose outer peripheral portion is surrounded by a fuel filter,
An electric starting fuel pump for a portable working machine, wherein the housing is movably accommodated in a fuel tank.