JP2003129925A - Forced air-cooled engine with recoil starter - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To simplify a structure by reducing the number of parts and to improve cooling efficiency. A center shaft is fixed to a crankshaft of an engine via a cooling fan.
The generator 4 is connected to the tip of. Further, a recoil housing 27 for accommodating the recoil reel 29 is disposed on the axis of the center shaft 21, and the outer periphery of the recoil housing 27 is fixed to the fan cover 20 to form a hub
A cooling air passage 28 is formed between a and the center shaft 21.
Further, an engaging protrusion 21b that engages with a recoil claw 30 that protrudes by centrifugal force supported by the recoil reel 29 is formed integrally with the base of the center shaft 21. Center shaft 21
Since the engaging projection 21b is formed integrally with the first embodiment, the number of parts can be reduced. Further, since the cooling air passage 28 is formed between the center shaft 21 and the hub 27a, the cooling efficiency is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a forced air cooling engine with a recoil starter equipped with a through recoil starter.

[0002]

2. Description of the Related Art Generally, in a forced air-cooled engine with a recoil starter of this type, a cooling fan and a recoil pulley are fixedly installed at the tip of a crankshaft extending from the engine.
Further, many recoil pulleys have a structure in which a recoil reel is provided in opposition.

When the recoil rope wound around the recoil reel is pulled, the recoil claw provided on the recoil reel projects and engages with the engaging portion formed on the recoil pulley, and this recoil pulley is pulled. The engine is started by transmitting the rotational force to the crankshaft via the engine.

Further, while the engine is operating, the cooling fan blows the cooling air to the engine to forcibly cool the engine.

[0005]

By the way, as disclosed in, for example, Japanese Patent Application Laid-Open No. 2001-207941, when a generator as a load means is connected to an engine, a conventional recoil starter is a recoil type. Since the pulley is fixed to the shaft end of the output shaft and the recoil reel is installed opposite to this shaft end with a predetermined distance, the recoil starter is arranged on the opposite side of the engine with the generator in between. It becomes a structure.

As a result, the distance between the recoil pulley and the engine output shaft becomes long, and the output shaft is apt to be twisted or the like. To cope with this, the strength of the output shaft itself is increased, or the shaft is in the middle. It is necessary to take measures such as providing a supporting portion, which not only complicates the structure but also increases the weight.

Further, when mounting the recoil starter, a recoil pulley has to be separately fixed on the output shaft side, and there is a disadvantage that the assembly becomes complicated.

Further, in the conventional forced air cooling engine, since the recoil starter is arranged in front of the cooling fan, this recoil starter becomes an obstacle when taking in outside air, and the cooling efficiency is lowered.

In view of the above circumstances, the present invention reduces the number of parts and improves the cooling efficiency, and even when the load means is connected to the engine, it is not necessary to consider the strength against torsion. Moreover, it is an object of the present invention to provide a forced air-cooled engine with a recoil starter, which has a simplified structure and a light weight, and is easy to manufacture and assemble.

[0010]

In order to achieve the above object, a forced air-cooled engine with a recoil starter according to the present invention connects a cooling fan and a center shaft to an output shaft of the engine, and a shaft of a recoil housing for accommodating a recoil reel. A hub provided at the center is loosely inserted into the center shaft, the recoil housing is fixed to the engine side, and a recoil claw that projects by a centrifugal force is arranged on the recoil reel. It is characterized in that an engaging portion which can be engaged is formed integrally with the center shaft.

In such a structure, since the engaging portion for engaging the recoil claw is integrally formed on the center shaft, the structure can be simplified.

In this case, preferably, 1) by forming a gap between the inner circumference of the recoil hub and the outer circumference of the center shaft, the gap serves as a cooling air passage, thereby improving cooling efficiency. .

2) By forming a slope surface that expands in the radial direction from the middle of the center shaft toward the base end side, the cooling air can be smoothly guided along the slope surface.

3) Since the load means is connected to the output shaft via the center shaft, the standard from the center shaft to the engine side can be unified regardless of the load means to be attached.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. Here, FIG. 1 is a sectional side view of an essential part of the engine generator, FIG. 2 is a perspective view of a fan cover, and FIG.
5 shows the center shaft, FIG. 3 is a front view, and FIG.
IV-IV sectional drawing, FIG. 5 is a V arrow side view of FIG.

In FIG. 1, reference numeral 1 is an engine generator, which is an example of a working machine, is equipped with a generator 4 as load means, and is rotated by a forced air-cooled engine (hereinafter abbreviated as “engine”) 3 to generate a generator 4. To drive electromotive force.

A cooling fan 17, which also functions as a flywheel, is fixedly installed at the shaft end of the crankshaft 3a as an output shaft protruding from the engine 3.
Cooling fins 16 are fixedly provided on the outer circumference of the surface of the cooling fin 16 that faces the generator 4. The cooling fan 17 is of a centrifugal type and discharges cooling air from the central portion toward the outer circumference. Further, the rear end of the center shaft 21 that constitutes the recoil starter 18 is screwed to the cooling fan 17.

The outer periphery of the cooling fan 17 is a fan cover 20.
Is housed in a fan chamber 20b provided in the fan chamber 20b.

The generator 4 is connected to the shaft end of the center shaft 21. In the figure, an outer rotor type multi-pole generator is shown as the generator 4, and a drum-shaped outer rotor 22 is fixedly provided at the shaft end of the center shaft 21. In the generator 4, a plurality of permanent magnets 23 are arranged on the inner circumference of the outer rotor 22 at equal intervals, and a stator 24 is provided opposite to the inner circumference of the permanent magnet 23. The stator 24 is formed of a stator core and a stator coil (none of which is shown) wound around the stator core, and the stator 24 serves as the end cover 2 for the generator.
5 is hooked on a boss 25a protruding from the inner peripheral surface of the member 5, and is fixed via a bolt (not shown).

On the other hand, a claw portion 20c extends from the fan cover 20 toward the generator 4 (note that a part of the claw portion 20c is omitted in FIG. 1). Further, the rear end of the generator duct 19 is mounted on the outer periphery of the claw portion 20c, and the rear end surface of the generator duct 19 is attached to a boss 20d protruding from the front surface of the fan cover 20 by a bolt (not shown). Is fixed through.

Further, the opening end of the generator end cover 25, which is open to the engine 3 side, is attached and fixed to the claw portion 20c extending from the fan cover 20, and the outer periphery of the generator end cover 25, A cooling air passage 26 is formed between the inner periphery of the generator duct 19 and the inner periphery.

On the other hand, the center shaft 21 is formed with a conical slope surface 21a that expands in the axial direction from the midway to the base end side, and further the shaft from the base end to the tip end side of the center shaft 21. A pair of opposing engaging projections 21b along the direction are projected.

A hub 27a formed at the center of the recoil housing 27 is externally inserted in the middle of the center shaft 21, and a cooling air passage 28 is formed between the inner periphery of the hub 27a and the center shaft 21. Has been formed.

Three flange portions 27b are formed on the outer circumference of the recoil housing 27. The flange portions 27b are provided on three bosses 20f projecting from the front surface of the fan cover 20 and bolts (not shown) are formed. Is fixed through.

A recoil reel 29 is housed in the recoil housing 27.
Is attached to the outer periphery of the hub 27a while being rotatably supported. This recoil reel 29
A recoil claw 30 is supported on the recoil reel 2
When the recoil rope 31 wound around 9 is pulled, the recoil reel 29 rotates in the normal direction, and the recoil claw 30 projects toward the cooling fan 17 by the centrifugal force, and the engaging projection integrally formed on the center shaft 21. The center shaft 21 is normally rotated by engaging the side surface 21c of 21b.

This rotational force is applied to the center shaft 21 and the cooling fan 1.
Is transmitted to the crankshaft 3a of the engine 3 via 7,
The engine 3 is started.

Next, the operation of this embodiment having such a configuration will be described. First, at the time of starting, a recoil rope 31 wound around a recoil reel 29 rotatably supported by a recoil housing 27 fixed to the fan cover 20 is pulled. Then, the recoil reel 29 is rotated in the normal direction, and the recoil claw 30 that is connected to the recoil reel 29 projects toward the cooling fan 17 due to the centrifugal force.

In the projecting direction of the recoil claw 30, an engaging projection 21b projecting from the base of the center shaft 21 fixed to the cooling fan 17 is provided opposite to the engaging projection. The recoil claw 30 engages with the side surface 21c of 21b,
The center shaft 21 is normally rotated.

As a result, the crankshaft 3a of the engine 3, which is connected to the center shaft 21 via the cooling fan 17, rotates in the forward direction, and the engine 3 is started.

In the present embodiment, the recoil housing 2
The flange 27b formed on the outer periphery of the fan cover 2
Since the hub 27a is fixed to 0 and the inner circumference of the hub 27a is not supported by the center shaft 21 passing through the hub 27a, the recoil reel 29 side reaction force is not applied to the center shaft 21. It is not necessary to increase the strength of the center shaft 21, and the structure can be simplified and the weight can be reduced.

The center shaft 21 is the recoil housing 2
Since it penetrates through 7 and projects to the generator 4 side, even when connecting other load means other than the generator 4 to this center shaft 21, it is necessary to change the mounting structure of the recoil housing 27. Without center shaft 21 to engine 3
It is possible to unify the structures up to, and it is possible to obtain excellent versatility.

When the crankshaft 3a is rotated by the operation of the engine 3, the outer rotor 22 of the generator 4 connected to the crankshaft 3a via the center shaft 21 is rotated, and the inner circumference of the outer rotor 22 is rotated. An electromotive force is generated in the coil of the stator 24 that is provided opposite to the inner circumference of the plurality of fixed permanent magnets 23, and power generation is started.

On the other hand, when the cooling fan 17 rotates due to the operation of the engine 3, a vent hole (not shown) opened in the generator end cover 25 provided in the generator 4 and this generator Cooling air is introduced into the generator 4 from a cooling air passage 26 formed between the end cover 25 and the generator duct 19 arranged on the outer periphery of the generator end cover 25, and power is generated. The inside of the machine 4 is cooled.

The cooling air passing through the generator 4 is
A cooling air passage 28 is formed between the outer circumference of the recoil housing 27 and the inner circumference of the power generation-use duct 19, and between the inner circumference of the hub 27 a formed at the axial center of the recoil housing 27 and the center shaft 21. As a result, the cooling fins 16 are guided in the inner peripheral direction and are discharged in the outer peripheral direction by the rotation of the cooling fins 16.

At this time, since the conical slope surface 21a that expands in the axial direction from the middle of the center shaft 21 to the base side is formed, the cooling air is directed along the slope surface 21a in the outer peripheral direction of the cooling fan 17. Can be smoothly guided to.

The cooling air discharged to the outer circumference of the cooling fan 17 is guided to the inner circumference of the fan chamber 20b formed in the fan cover 20 and discharged toward the engine 3 to cool the engine 3 and then to the outside. It is discharged to people.

As described above, according to the present embodiment, since the engaging projection 21b that engages with the recoil claw 30 constituting the recoil starter 18 is integrally formed with the center shaft 21, the number of parts is reduced and the structure is improved. Simplification can be realized and manufacturing and assembling becomes easy.

The outer periphery of the recoil housing 27 is fixed to the fan cover 20, and the cooling air passage 2 is provided between the hub 27a and the center shaft 21 penetrating the hub 27a.
Since 8 is formed, the cooling air can be guided through the cooling air passage 28, the flow of the cooling air is improved, the cooling efficiency of the engine 3 can be improved, and the high output of the engine 3 can be supported. You can

The recoil housing 27 has a center shaft 2
Since it is arranged on one shaft, it is not necessary to change the mounting structure for each load means such as the generator 4 connected to the center shaft 21, and the standard can be unified, which is excellent in versatility. Can be obtained.

The present invention is not limited to the above-described embodiment, and the working machine may be an engine pump having a water pump as a load means, for example. Further, the present invention can be applied to a general-purpose engine to which the load means is not connected.

[0041]

As described above, according to the present invention,
The outside air can be taken in easily and the engine can be cooled efficiently.

Further, even when the load means is connected to the engine, it is not necessary to change the mounting structure of the recoil starter, and the standardization can be realized.

Further, since the engaging portion for engaging the recoil claw is integrally formed on the center shaft, the number of parts can be reduced and the structure can be simplified, and the manufacturing and assembling can be facilitated.

[Brief description of drawings]

FIG. 1 is a sectional side view of an essential part of an engine generator.

FIG. 2 is a perspective view of a fan cover.

[Fig. 3] Front view of the center shaft

4 is a sectional view taken along line IV-IV in FIG.

5 is a side view of FIG. 3 as seen in the direction of arrow V. FIG.

[Explanation of symbols]

1 engine generator 3 engine 3a Crankshaft (output shaft) 4 generator (load means) 16 cooling fins 17 Cooling fan 18 recoil starter 19 Generator duct 20 fan cover 20a Flange part 20b fan room 20c claw 20d, 20f boss 21 Center axis 21a Slope surface 21b Engagement protrusion 21c side 22 Outer rotor 23 Permanent magnet 24 stator 25 End cover for generator 25a boss 26 Cooling air passage 27 Recoil housing 27a hub 27b Flange part 28 Void (cooling air passage) 29 Recoil reel 30 recoil claws 31 Recoil rope

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Tadao Kuwahara             1-7-2 Nishi-Shinjuku, Shinjuku-ku, Tokyo Fuji             Heavy Industry Co., Ltd.

Claims (4)

[Claims] 1. A cooling fan and a center shaft are connected to an output shaft of an engine, a hub provided in the center of a recoil housing for accommodating a recoil reel is loosely inserted in the center shaft, and the recoil housing is attached to the engine side. A recoil reel fixed to the center of the recoil reel, wherein the recoil reel is provided with a recoil claw protruding by a centrifugal force, and an engaging portion that is engageable with the recoil claw when projecting is integrally formed with the center shaft. Forced air-cooled engine with starter. 2. A forced air cooling engine with a recoil starter according to claim 1, wherein a gap is formed between the inner circumference of said recoil hub and the outer circumference of said center shaft. 3. A forced air cooling engine with a recoil starter according to claim 1 or 2, wherein a slope surface that expands in the radial direction of the shaft is formed from the middle of the center shaft toward the base end side. 4. A forced air cooling engine with a recoil starter according to claim 1, wherein a load means is connected to the output shaft through the center shaft.