JP4082485B2 - Forced air-cooled engine with recoil starter - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a forced air cooling engine with a recoil starter provided with a through-type recoil starter.
[0002]
[Prior art]
Generally, this type of forced air cooling engine with a recoil starter has a structure in which a cooling fan and a recoil pulley are fixed to the tip of a crankshaft extending from the engine, and a recoil reel is paired with the recoil pulley. There are many things.
[0003]
When the recoil rope wound around the recoil reel is pulled, the recoil pawl provided on the recoil reel protrudes and engages with an engagement portion formed on the recoil pulley, and the crank is inserted through the recoil pulley. The engine is started by transmitting the rotational force to the shaft.
[0004]
During engine operation, cooling air is blown to the engine by the rotating cooling fan, and the engine is forcibly cooled.
[0005]
[Problems to be solved by the invention]
Incidentally, 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 fixes a recoil pulley to the shaft end of the output shaft. In addition, since the recoil reel is disposed opposite to the shaft end with a predetermined distance, the recoil starter is disposed on the opposite side of the engine with the generator interposed therebetween.
[0006]
As a result, the distance between the recoil pulley and the engine output shaft becomes long, and the output shaft is liable to be twisted or the like. To cope with this, the strength of the output shaft itself is increased, or the shaft support part is installed on the way. It is necessary to take measures such as providing it, which not only complicates the structure but also increases the weight.
[0007]
Further, when the recoil starter is attached, a recoil pulley must be separately fixed on the output shaft side, resulting in inconvenience of assembly.
[0008]
Further, in the conventional forced air cooling engine, since the recoil starter is disposed in front of the cooling fan, the recoil starter becomes an obstacle when taking in outside air, and the cooling efficiency is lowered.
[0009]
In view of the above circumstances, the present invention aims to reduce the number of parts and improve the cooling efficiency, and even when a load means is connected to the engine, it is not necessary to consider the strength against torsion, and the structure An object of the present invention is to provide a forced air-cooled engine with a recoil starter that is simple and lightweight and can be easily manufactured and assembled.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, a forced air cooling engine with a recoil starter according to the present invention includes an engine, a cooling fan fixed to an output shaft of the engine, a fan cover provided in the engine and accommodating the cooling fan, A center shaft provided at one end of the output shaft; and a recoil starter for starting the engine. The recoil starter is disposed on the center shaft outside the fan cover and has a recoil rope. a recoil reel is wound, is composed of a recoil housing having a hub for supporting a rotational center portion of the recoil reel rotatably, the hub is loosely inserted into the center shaft, an inner periphery of the hub and An air gap is formed between the outer periphery of the center shaft .
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings. 1 is a sectional side view of the main part of the engine generator, FIG. 2 is a perspective view of the fan cover, FIGS. 3 to 5 are center shafts, FIG. 3 is a front view, and FIG. IV sectional view, FIG. 5 is a side view of FIG.
[0016]
In FIG. 1, reference numeral 1 denotes an engine generator that is an example of a work machine, and includes a generator 4 as a load unit, and the generator 4 is driven by the rotational force of a forced air-cooled engine (hereinafter simply referred to as “engine”) 3. To generate electromotive force.
[0017]
A cooling fan 17 also serving as a flywheel is fixed to the shaft end of a crankshaft 3a as an output shaft protruding from the engine 3, and the cooling fan 17 has an outer periphery on the surface directed to the generator 4 side. Cooling fins 16 are fixed. The cooling fan 17 is a centrifugal type, and cooling air is discharged from the center portion toward the outer periphery. Further, the rear end of the center shaft 21 constituting the recoil starter 18 is screwed to the cooling fan 17.
[0018]
The outer periphery of the cooling fan 17 is accommodated in a fan chamber 20b provided in the fan cover 20, and a flange portion 20a formed at the opening end of the fan chamber 20b is fixed to the engine 3 side.
[0019]
The generator 4 is connected to the shaft end of the center shaft 21. In the drawing, an outer rotor type multipolar generator is shown as the generator 4, and an outer rotor 22 formed in a drum shape is fixed to the shaft end of the center shaft 21. In the generator 4, a plurality of permanent magnets 23 are arranged at equal intervals on the inner periphery of the outer rotor 22, and a stator 24 is provided on the inner periphery 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 projects from the inner peripheral surface of the generator end cover 25. It is hooked on the boss 25a and fixed through a bolt (not shown).
[0020]
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, a rear end of the generator duct 19 is mounted on the outer periphery of the claw portion 20c, and a bolt (not shown) is attached to a boss 20d whose rear end surface projects from the front surface of the fan cover 20. It is fixed through.
[0021]
An opening end of the generator end cover 25 that opens to the engine 3 side is attached and fixed to a claw portion 20c extending from the fan cover 20, and the outer periphery of the generator end cover 25 and the generator end cover 25 are fixed. A cooling air passage 26 is formed between the inner periphery of the duct 19.
[0022]
On the other hand, the center shaft 21 is formed with a conical slope surface 21a that expands in the axial direction from the middle to the base end side. Further, the center shaft 21 extends in the axial direction from the base end to the distal end side. A pair of opposing engaging protrusions 21b are protruded.
[0023]
A hub 27 a formed at the center of the recoil housing 27 is inserted in the middle of the center shaft 21. A cooling air passage 28 is formed between the inner periphery of the hub 27 a and the center shaft 21. Yes.
[0024]
Three flange portions 27b are formed on the outer periphery of the recoil housing 27, and the flange portions 27b are formed on three bosses 20f protruding from the front surface of the fan cover 20 via bolts (not shown). It is fixed.
[0025]
A recoil reel 29 is accommodated in the recoil housing 27, and a rotation center portion of the recoil reel 29 is attached to the outer periphery of the hub 27a so as to be rotatable. A recoil claw 30 is supported on the recoil reel 29, and when the recoil rope 31 wound around the recoil reel 29 is pulled, the recoil reel 29 rotates forward and the recoil claw 30 moves toward the cooling fan 17 by centrifugal force. It protrudes and engages with the side surface 21c of the engaging protrusion 21b formed integrally with the center shaft 21, so that the center shaft 21 is rotated forward.
[0026]
This rotational force is transmitted to the crankshaft 3a of the engine 3 via the center shaft 21 and the cooling fan 17, and the engine 3 is started.
[0027]
Next, the operation of the present embodiment having such a configuration will be described.
First, at the time of starting, the recoil rope 31 wound around the recoil reel 29 rotatably supported by the recoil housing 27 fixed to the fan cover 20 is pulled. Then, the recoil reel 29 rotates in the forward direction, and the recoil pawl 30 connected to the recoil reel 29 protrudes toward the cooling fan 17 by centrifugal force.
[0028]
In the projecting direction of the recoil pawl 30, an engaging projection 21 b projecting from the base of the center shaft 21 fixed to the cooling fan 17 is provided opposite to the side surface of the engaging projection 21 b. The recoil claw 30 is engaged with 21c, and the center shaft 21 is rotated forward.
[0029]
As a result, the crankshaft 3a of the engine 3 connected to the center shaft 21 via the cooling fan 17 rotates normally, and the engine 3 is started.
[0030]
In the present embodiment, the flange portion 27b formed on the outer periphery of the recoil housing 27 is fixed to the fan cover 20, and the inner periphery of the hub 27a is not supported by the center shaft 21 penetrating the hub 27a. The reaction force on the recoil reel 29 side is not applied to the center shaft 21. Therefore, it is not necessary to increase the strength of the center shaft 21, and the structure can be simplified and reduced in weight.
[0031]
Further, since the center shaft 21 penetrates the recoil housing 27 and protrudes toward the generator 4 side, even when a load means other than the generator 4 is connected to the center shaft 21, the recoil housing 27. There is no need to change the mounting structure, and the structure from the center shaft 21 to the engine 3 can be unified, and excellent versatility can be obtained.
[0032]
When the crankshaft 3 a rotates due to the operation of the engine 3, the outer rotor 22 of the generator 4 connected to the crankshaft 3 a via the center shaft 21 rotates, and is fixed to the inner periphery of the outer rotor 22. An electromotive force is generated in the coil of the stator 24 provided on the inner periphery of the plurality of permanent magnets 23, and power generation is started.
[0033]
On the other hand, when the cooling fan 17 rotates due to the operation of the engine 3, a vent (not shown) opened in the generator end cover 25 provided in the generator 4 and the generator end cover 25. And cooling air is introduced into the generator 4 from the cooling air passage 26 formed between the generator end cover 25 and the generator duct 19 disposed on the outer periphery of the generator end cover 25. Cool down.
[0034]
The cooling air that has passed through the generator 4 passes between the outer periphery of the recoil housing 27 and the inner periphery of the power generation duct 19 and the inner periphery of the hub 27a formed at the axial center of the recoil housing 27 and the center shaft. Through the cooling air passage 28 formed between the cooling fin 16 and the cooling fin 16, the cooling fin 16 is guided to the inner circumferential direction.
[0035]
At this time, since a 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 can be smoothly moved along the slope surface 21a in the outer peripheral direction of the cooling fan 17. Can lead.
[0036]
The cooling air discharged to the outer periphery of the cooling fan 17 is guided to the inner periphery of the fan chamber 20 b formed in the fan cover 20, is discharged toward the engine 3, cools the engine 3, and then discharges outward. Is done.
[0037]
As described above, according to the present embodiment, since the engaging protrusion 21b that engages with the recoil claw 30 constituting the recoil starter 18 is formed integrally with the center shaft 21, the number of parts can be reduced and the structure can be simplified. It can be realized, and manufacturing and assembly become easy.
[0038]
Further, the outer periphery of the recoil housing 27 is fixed to the fan cover 20, and a cooling air passage 28 is formed between the hub 27a and the center shaft 21 passing through the hub 27a. Since the cooling air can be guided through the cooling air, the flow of the cooling air can be improved, the cooling efficiency of the engine 3 can be increased, and the high output of the engine 3 can be coped with.
[0039]
Further, since the recoil housing 27 is disposed on the axis of the center shaft 21, 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 standards are unified. And excellent versatility can be obtained.
[0040]
In addition, this invention is not restricted to embodiment mentioned above, For example, a working machine may be an engine pump which uses a load means as a water pump. Furthermore, it is possible to apply the present invention to a general-purpose engine to which load means is not connected.
[0041]
【The invention's effect】
As described above, according to the present invention, since the gap is formed between the inner periphery of the hub that rotatably supports the recoil reel and the outer periphery of the center shaft, the outside air can be easily taken in. The engine can be cooled efficiently.
[0042]
Further, even when load means are connected to the engine, it is not necessary to change the mounting structure of the recoil starter, and standardization can be realized.
[0043]
Furthermore, since the engaging portion that engages with the recoil pawl is integrally formed on the center shaft, the number of parts can be reduced and the structure can be simplified, and manufacturing and assembly are facilitated.
[Brief description of the drawings]
1 is a cross-sectional side view of an essential part of an engine generator. FIG. 2 is a perspective view of a fan cover. FIG. 3 is a front view of a center shaft. FIG. 4 is a cross-sectional view taken along IV-IV in FIG. V arrow side view [Explanation of symbols]
1 Engine generator 3 Engine 3a Crankshaft (output shaft)
4 Generator (loading means)
16 Cooling fin 17 Cooling fan 18 Recoil starter 19 Generator duct 20 Fan cover 20a Flange portion 20b Fan chamber 20c Claw portion 20d, 20f Boss 21 Center shaft 21a Slope surface 21b Engaging protrusion 21c Side surface 22 Outer rotor 23 Permanent magnet 24 Stator 25 End cover 25a for generator 25 Boss 26 Cooling air passage 27 Recoil housing 27a Hub 27b Flange 28 Air gap (cooling air passage)
29 Recoil reel 30 Recoil claw 31 Recoil rope

Claims (4)

Engine,
A cooling fan fixed to the output shaft of the engine;
A fan cover provided in the engine and accommodating the cooling fan;
A center shaft provided on one end side of the output shaft;
A recoil starter for starting the engine;
With
The recoil starter is disposed on the center shaft outside the fan cover and has a recoil reel around which a recoil rope is wound, and a recoil having a hub that rotatably supports a rotation center portion of the recoil reel. Consisting of a housing,
The hub is loosely inserted into the center shaft, a forced air-cooled engine with a recoil starter, wherein <br/> the air gap is formed between an outer periphery of the inner periphery and the center axis of the hub. The center axis claim 1 recoil starter with forced air cooling engine, wherein the slope surface whose diameter increases in the shaft diameter direction toward the end portion attaching the middle to one end of the output shaft is formed. The forced air-cooled engine with a recoil starter according to claim 1 or 2 , wherein a load means is connected to the output shaft via the center shaft. The recoil reel has a recoil pawl that projects by a centrifugal force generated by pulling the recoil rope, and the center shaft has an engaging portion that can be engaged with the recoil pawl when projecting. The forced air cooling engine with a recoil starter according to any one of claims 1 to 3.

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