JPH0236906Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention relates to a two-stroke internal combustion engine suitable for backpack-type power spreaders, etc., and more specifically, the invention relates to a two-stroke internal combustion engine suitable for backpack-type power spreaders, etc. A shaft is provided in a position perpendicular to the crankshaft, and a gear connected to the operating rope pulley of the recoil starter via a helical spline connection portion or the like is arranged around the shaft,
The present invention relates to a two-stroke internal combustion engine equipped with a recoil starter in which the gear moves in the longitudinal direction of the shaft and meshes with a ring gear on the crankshaft side as the pulley rotates.

[Problems to be solved by conventional technology and ideas] In general, in this type of internal combustion engine, various devices such as a recoil starter, carburetor, air cleaner, muffler, and blower fan are installed adjacent to the main body of the internal combustion engine. The layout is difficult,
In particular, when installing a so-called horizontal plunge type recoil starter that is arranged perpendicular to the crankshaft, it is difficult to secure an appropriate installation space for the recoil starter and carburetor because the other equipment gets in the way. The prior art showing the support structure of the crankshaft is Utility Model Publication No. 51-43308.
There is.

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention provides a two-stroke internal combustion engine with a cantilevered crankshaft, and provides a cantilever type crankshaft in the vicinity of the crankcase bearing that supports the crankshaft, which is perpendicular to the crankshaft. A horizontal plunge type recoil starter is provided, a mixture inlet is provided at the end of the crankcase located on the opposite side in the crankshaft direction with respect to the bearing part, a carburetor is connected to the mixture inlet, and an air cleaner is connected to the carburetor. is provided near the end of the crankcase.

Next, embodiments will be described with reference to the drawings.

[Example] In FIG. 1, which is a vertical cross-sectional view, the crankshaft 2 of the engine body 1 having a cylinder C and a piston P is of a cantilevered type, and a crank arm 4 is provided only on the right side of the crank pin 3 in FIG. The crankshaft 2 is supported by a cylindrical boss 6 provided on the right wall of the crankcase 5 in FIG. 1 via a bearing 7 and a seal 8. A blower fan 10 is attached to the end of the crankshaft 2 protruding from the boss 6 by means of bolts 9 and keys.
A boss 11 is fixed. In the illustrated embodiment, the boss 11 is formed integrally with the main body of the blower fan 10, but the two may be formed as separate parts and integrated with bolts or the like. The crankcase 5 includes a cover portion 15 that covers the back surface (left side in FIG. 1) of the blower fan 10, and a fan case 16 is fixed to the outer circumferential portion of the cover portion 15. The fan case 16 covers the outer periphery and front surface of the blower fan 10 and forms a spiral chamber 17 around the blower fan 10. 18 is an air suction port. A drug tank 20 is attached to the upper surface of the fan case 16, and although not shown, the outlet passage of the drug tank 20 is connected to the outlet or the vicinity of the outlet of the vortex chamber 17 directly or via a mixer or the like. .

A fan case front wall 21 covering the front surface of the blower fan 10 is provided with bosses 22 at the upper and lower parts, and a backpack frame 25 is fixed to the bosses 22 via a damper 23. Back straps 27 are attached to the upper and lower ends of the backpack frame 25 via metal rings 26. 28 is a backpack board. Note that the backpack frame 25 and backpack belt 27 can also be fixed to the crankcase 5 or the like.

The cover portion 15 covers the bosses 6 and 11 and forms a chamber 29 below the bosses 6 and 11, and an ignition coil 30 and an iron core 31 are provided in the chamber 29. The coil 30 and the iron core 31 are fixed to the boss of the upward wall 33 at the tip of the cover part 15, and the ignition coil magnet 32 facing the iron core 31 is embedded in the outer peripheral surface of the boss 11.

As shown in FIG. 2, which is an enlarged partial cross-sectional view of FIG. It has been fixed. The shaft may be inserted and fixed as a drilled hole instead of a screw hole. The shaft 37 is perpendicular to the crankshaft 2, and a cylindrical shaft 40 protruding from the inner periphery of the rope pulley 39 is rotatably fitted and supported on the outer periphery of the shaft 37, and a gear 41 is fitted into a helical spline on the outer periphery of the cylindrical shaft 40. It matches. The helical spline is configured such that when the pulley 39 and cylinder shaft 40 are rotated by the rope 38, the gear 41 moves forward toward the boss 6 as indicated by arrow F.
A ring gear 42 is provided on the outer periphery of the end surface of the boss 11, with which the gear 41 engages when moving forward. Cylindrical shaft 4
A compression coil spring 43 is provided around 0.
The spring 43 is used to move the gear 41 backward in the direction of the reverse arrow F, and has one end in pressure contact with the gear 41 and the other end in pressure contact with a spring receiver 45 provided near the boss 6. The pulley 39 holds the spring 4 with the gear 41 in between.
It is located on the opposite side of 3. A cover 46 that covers the pulley 39 and the like is attached to the tip of the shaft 37, and a spring 49 is provided inside the cover 46 to bias the pulley 39 in the rope rewinding direction. 5
0 is a handle attached to the tip of the rope 38.

As shown in FIG. 3, which is a view taken from the - arrow in FIG. , handle 5
0 is located at the upper end of the recoil starter 36. The muffler 51 is provided on the right side of the engine body 1.

In FIG. 1, a crankcase cover 55 is provided on the left end of the crankcase 5, that is, on the opposite side in the crankshaft direction with respect to the boss 6.
The cover 55 is a member that also serves as the body of the reed valve 59, and is attached to the crankcase 5 by bolts (not shown).
Fixed to the main body. The cover 55 has a mixture inlet 57 which becomes larger in diameter as it goes toward the crank chamber 56 side.
is provided at a position approximately concentric with the crankshaft 2, and the cover 5
A reed valve 59 for opening and closing the inlet 57 and a lower end portion of a stopper 60 are fastened together with bolts 61 on the inner surface of the reed valve 5 . The stopper 60 is for regulating the maximum open position of the reed valve 59, and its top and both sides are separated from the cover 55. Note that the reed valve body can also be provided separately from the cover 55. Further, the cover 55 can also be formed integrally with the crankcase 5.

A carburetor 64 is fixed to the outer surface of the cover 55. The carburetor 64 is located approximately on an extension of the crankshaft 2, and an air cleaner 62 is fixed to a surface of the carburetor 64 opposite to the cover 55. Among the various parts of the air cleaner 62, the element accommodating part 63, which occupies a large space, is inserted under the carburetor 64 and the cover 55.

Explain the operation. When the rope 38 shown in FIG. 2 is pulled to turn the pulley 39 and the crankshaft 2 is turned via the gears 41 and 42, the engine is started and the blower fan 10 is rotated to become ready to spray the medicine.
When the crank chamber 56 becomes negative pressure due to the rise of the piston P in FIG.
The air-fuel mixture is sucked into the crank chamber 56 through. In this operation, the air-fuel mixture directly drawn into the crank chamber 56 comes into contact with the big end bearing 3a around the crank pin 3, so the air-fuel mixture causes the bearing to
a is cooled and lubricated (in case of mixed lubrication). In addition, the fourth part of the schematic diagram of the part shown in the − arrow direction in FIG.
As shown by arrow R in the figure, the air-fuel mixture flows from the inlet 57 along the surface of the reed 59 upwards and in the left-right direction.
Since the air-fuel mixture is drawn toward the ascending crank pin 3, a large amount of the air-fuel mixture comes into contact with the bearing 3a, and the bearing 3a is sufficiently cooled and lubricated. In addition, since the air-fuel mixture blown upward from the inlet 57 flows into the cylinder C shown in FIG. 1, the heat of the cylinder C promotes atomization of the air-fuel mixture, improving combustion and reducing fuel consumption. Cylinder C is also cooled to suppress thermal deformation.

According to the structure of the present invention described above, the horizontal plunge type recoil starter 36 is provided near the crankcase bearing portion (boss 6) and perpendicular to the crankshaft 2. Moreover, the crankshaft 2 is made cantilevered so that there is no need to provide a bearing at one end of the crankcase (cover 55). On the other hand, it is possible to provide the air-fuel mixture inlet 57 at the end of the crankcase located on the opposite side in the crankshaft direction, thereby arranging the carburetor 64 and air cleaner 62 connected to the air-fuel mixture inlet 57 near the end of the crankcase. making it possible to do so.

In this way, in the present invention, the recoil starter 36
The intake-related equipment (the carburetor 64 and the air cleaner 62) can be placed apart from each other, and the intake-related equipment can be removed from the space on the opposite side of the recoil starter 36 by sandwiching the engine body such as the crankcase. , the space on the opposite side can be used as an installation space for other equipment (for example, the muffler 51). As a result, the carburetor 64, the air cleaner 62, and the recoil starter 36 can be installed apart from each other and, for example, away from the muffler 51, and the installation space for them can be easily secured.

In particular, horizontal plunge type recoil starters are generally
In order to ensure the reduction ratio between the ring gear 42 and the gear 41 (pinion), it is necessary to make the gear 41 small in diameter and to install the entire starter 36 closer to the ring gear 42 side to ensure gear meshing. With the conventional structure, it is not only difficult to secure installation space when considering interference with other equipment, but also has restrictions in terms of functionality, such as restrictions on the reduction ratio between the ring gear 42 and the gear 41. However, as mentioned above, with the structure of the present invention, it is easy to secure the installation space, so it is possible to arbitrarily select the reduction ratio between the ring gear 42 and the gear 41, and the horizontal plunge type recoil starter 36 is Can be installed.

In the illustrated embodiment, since the crankcase cover 55 also serves as the main body of the reed valve 59, it is possible to reduce the number of component parts and the number of assembly steps, thereby reducing costs. Also, connect the air-fuel mixture inlet 57 to the crank pin 3.
Since the air-fuel mixture is provided adjacent to the crank chamber 56, the large end bearing 3a is
The bearing 3a can be sufficiently cooled and lubricated, and the life of the bearing 3a can be extended.

Furthermore, if the present invention is used to configure a power spreader as shown in the drawings, and the recoil starter 36 is provided on the side of the backpack frame 25 with respect to the engine body 1, the center of gravity of the entire power spreader will be shifted to the side of the backpack frame 25. This makes it easier for workers to carry the power spreader on their backs, reducing fatigue. Note that power sprayers to which the present invention can be applied include not only sprayers for chemicals and the like, but also devices for cleaning fallen leaves and the like by blowing out only air.

[Brief explanation of the drawing]

Fig. 1 is a vertical sectional view of the embodiment, Fig. 2 is an enlarged partial cross-sectional view of Fig. 1, and Fig. 3 is - of Fig. 1.
The arrow view, FIG. 4 is an enlarged schematic view of FIG. 1 in the - arrow direction. 2...Crankshaft, 6...Boss (crankcase bearing), 37...Shaft, 39...Rope pulley, 41...Gear, 42...Ring gear, 55...Crankcase cover (crankcase end) section), 57...Mixture inlet, 64...Carburetor.

Claims (1)

[Scope of utility model registration request] A two-stroke internal combustion engine is provided with a cantilevered crankshaft, and a recoil starter is provided in the vicinity of a crankcase bearing that supports the crankshaft, with the shaft of the recoil starter being orthogonal to the crankshaft,
A ring gear is provided on the outer periphery of the end face of the boss fixed to the crankshaft, and is connected to the operating rope pulley of the recoil starter, so that by rotation of the pulley,
A gear that moves toward the crankshaft in the longitudinal direction of the shaft and meshes with the ring gear is arranged around the shaft, and a mixture inlet is provided at the end of the crankcase located on the opposite side in the crankshaft direction with respect to the bearing part. A two-stroke internal combustion engine characterized in that a carburetor connected to an air-fuel mixture inlet and an air cleaner connected to the carburetor are provided near the end of the crankcase.