JP5655407B2 - Two-cycle engine and portable work machine equipped with the same - Google Patents

Description

  The present invention relates to a scavenging passage cover shape of a two-cycle engine.

  An example of a conventional 2-cycle engine will be described with reference to FIGS.

  In the two-cycle engine, a mixed gas of fuel and air sucked into the crank chamber 13 from the intake port 14 as the piston 10 is raised is guided to the scavenging passages 1d and 1e as the piston 10 is lowered. At the same time as being supplied to the combustion chamber 1c, the ignition plug 4 ignites and burns, the piston 10 is driven by the combustion pressure, and the crankshaft 12 is rotated via the connecting rod 11 connected to the piston 10.

  As described above, the cylinder 1 is provided with the two scavenging passages 1d and 1e for introducing the mixed gas from the crank chamber 13 to the combustion chamber 1c of the cylinder 1, but the molding of the cylinder 1, which is mainly made of aluminum die casting, is provided. In order to facilitate the manufacture of the mold, a part of the scavenging passages 1d and 1e has a hole shape that leads to the outside.

  Since this hole-like shape needs to be closed in terms of function, the scavenging path cover 5 and the scavenging path cover 6 are attached to the cylinder 1 with screws 7a and 7b through a packing member 9 for ensuring confidentiality.

  A magnet rotor 3 containing a magnet is attached to the crankshaft 12, and an ignition coil 2 that generates electric power by rotating the magnet rotor 3 and supplies power to the spark plug 4 is adjacent to the magnet rotor 3. Are arranged.

  The ignition coil 2 is fixed to two mounting seats 1a and 1b provided on the cylinder 1 by screws 7c and 7d via heat insulating members 8a and 8b.

  In the two-cycle engine in the above prior art, the heat conducted and accumulated in the cylinder 1 due to the combustion of the mixed gas is conducted to the ignition coil 2 through the mounting seats 1a and 1b, and the resistance elements existing inside the ignition coil 2 and the like. In order to suppress the heat transfer as much as possible, it is necessary to dispose the heat insulating members 8a and 8b between the mounting seats 1a and 1b and the ignition coil 2 as described above. This led to a decrease in productivity and increased costs due to an increase in the number of parts.

JP 2009-299605 A

  In the conventional two-cycle engine as described above, it is necessary to provide a heat insulating member between the mounting seat and the ignition coil, which leads to deterioration in productivity and cost increase due to an increase in the number of parts.

  The present invention has been made in view of such problems, and it is an object of the present invention to improve productivity and reduce costs by reducing the number of parts in a two-cycle engine using a scavenging passage cover.

A two-cycle engine according to a first aspect of the present invention has a crank chamber and a combustion chamber, and is formed with a scavenging passage inlet opened in the crank chamber and a scavenging passage outlet opened in the combustion chamber. A part of the engine body including the main body, the scavenging path inlet, and the scavenging path outlet is covered, and a scavenging path cover that forms a scavenging path is rotatably supported by the crankcase, and a magnet rotor is connected. A drive output shaft;
An ignition coil disposed adjacent to the magnet rotor and generating electric power by rotating the magnet rotor and supplying electric power to an ignition plug; the ignition coil is attached to the scavenging passage cover It is characterized by being.

  Moreover, it is desirable that a heat insulating member is interposed between the scavenging passage cover and the engine body.

  Furthermore, it is desirable that the heat insulating member is configured as a seal member that seals between the scavenging passage cover and the engine body.

  Further, the scavenging path cover may be formed with an extending portion protruding in the axial direction of the drive output shaft, and the ignition coil may be attached to the extending portion.

  Further, it is desirable that the ignition coil is provided at a position overlapping the scavenging path cover when viewed in the axial direction of the drive output shaft.

  Furthermore, it is preferable that the ignition coil is attached adjacent to the scavenging passage of the scavenging passage cover.

  A portable work machine according to a second aspect of the present invention includes the two-stroke engine described above.

  A portable work machine characterized by that.

  According to the present invention, in a two-cycle engine using a scavenging passage cover, a seat surface for attaching an ignition coil is provided on the scavenging passage cover, and the number of heat insulating members is reduced, thereby improving productivity and reducing the number of parts. Can reduce costs.

A portable work machine equipped with a two-cycle engine according to an embodiment of the present invention 1 is an external view showing a two-cycle engine according to an embodiment of the present invention. External view with ignition coil removed in FIG. AA sectional view in FIG. B arrow view in FIG. External view showing a conventional 2-cycle engine External view with the ignition coil removed in FIG. CC sectional view in FIG. D view in FIG. 6 EE sectional view in FIG.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 to 5. In the following drawings, parts having the same function are denoted by the same reference numerals, and repeated description is omitted.

  FIG. 1 is a perspective view showing an entire blower apparatus 101 according to an embodiment of the present invention. FIG. 2 is a side view of the two-cycle engine mounted on the blower device 101 according to the embodiment of the present invention, and FIG. 3 is a side view showing a state where the ignition coil 2 is removed from the state of FIG. . 4 is a cross-sectional view taken along the line AA in FIG. 2, and FIG. 5 is a side view as seen from the direction of the arrow B in FIG. The blower device 101 mainly covers a main housing 102, a two-cycle engine 201 housed in the main housing 102, a fan housing 103 housing a fan for blowing air, and a suction port formed in the fan housing 103. It consists of a dustproof cover 104 and a discharge pipe for discharging the wind generated by the fan. In the present embodiment, the discharge pipe portion is an example constituted by a discharge pipe of the blower apparatus main body, two detachable pipes 119, and a nozzle 118. Two legs are formed in the lower part of the main housing 102 and the fan housing 103, and legs that also serve as handles are attached to the sides of these legs.

  A handle portion 107 for carrying the blower device 101 or holding it during work is formed on the upper portion of the housing. The handle unit 107 can be used to hold the blower device 101. In addition, if the blower device 101 is tilted sideways and the handle portion 107 is gripped with the right hand and the leg portion is gripped with the left hand, the angle of the nozzle 118 at the tip can be rotated by 90 degrees. It is configured to be able to.

  As shown in FIG. 10, the two-cycle engine 201 accommodated in the blower device 101 is composed of a cylinder 1 and a crankcase 16. In the cylinder 1, the top surface of the piston 10, the inner periphery of the cylinder 1, and the ceiling A combustion chamber 1c is defined by the section, and the crankcase 16 includes a crank chamber 13 in which the crankshaft 12, the connecting rod 11, a crank weight, and the like are accommodated. The cylinder 1 is formed of an aluminum alloy, and a cylinder bore inner peripheral surface is formed on the inner periphery of the cylinder 1 so as to be fitted with a piston 10 so as to be slidable up and down. In the present specification, the vertical direction of the paper surface on which the piston 10 slides will be described as the axial direction of the cylinder.

  In the cylinder 1, the intake port 14 and the exhaust port 15 are disposed 180 degrees apart from each other with the combustion chamber 1 c interposed therebetween when viewed in the cylinder axial direction, and the scavenging passage 1 d is provided between the intake port 14 and the exhaust port 15. , 1e are formed. The scavenging passages 1d and 1e extend in the cylinder axial direction and connect the crank chamber on the crankcase side and the combustion chamber of the cylinder 1. The scavenging passage cover 5 and the scavenging passage cover 6 are attached 90 degrees apart from the intake passage and the exhaust passage. The scavenging passage 1d is partly defined by the scavenging passage cover 5 and the cylinder 1. Similarly, the scavenging passage 1 e is partly defined by the scavenging passage cover 6 and the cylinder 1. A partition wall that divides the scavenging passages 1d and 1e in the circumferential direction protrudes from the scavenging passage cover, and the divided scavenging passages burn through the exhaust port side scavenging opening and the anti-exhaust port side scavenging opening, respectively. Connected to the room.

  As shown in FIG. 2, an ignition coil 2 is attached to the cylinder 1, and the ignition coil 2 is connected to a spark plug 4 attached to the top of the cylinder 1 via a plug cord 17. Near the end of the crankshaft 12, a magnet rotor 3 having a magnet attached to the outer peripheral end face over a predetermined angular range is provided. The magnet rotor 3 is integrally formed with a cooling fan, which generates cooling air by rotating and contributes to cooling of the cylinder 1 and its peripheral components. The ignition coil 2 is arranged adjacent to the outer side of the magnet rotor 3 with a predetermined air gap, and a magnet and an ignition coil attached to the outer peripheral end surface of the magnet rotor 3 by rotation of the crankshaft 12. Repeats close and spaced apart to generate a high voltage, and a spark is generated between the electrodes of the spark plug 4 protruding into the combustion chamber.

  As shown in FIG. 3, the scavenging path cover 5 is formed of an aluminum alloy, and is attached to the cylinder 1 via screws 7 a and 7 b. The basic components are the same as in the prior art, but the scavenging passage cover 5 is provided with one mounting seat 5a (extended portion) for mounting the ignition coil 2 and mounting for mounting the ignition coil 2 on the cylinder 1 as well. One seat 1a is provided. The mounting seat 5a is integrally formed by extending in the axial direction of the crankshaft 12 from the vicinity of the outside where the scavenging passage is formed. Female screws are respectively formed on the mounting seat 1a and the mounting seat 5a.

  The ignition coil 2 is fixed to the mounting seat 1a provided on the cylinder 1 and the mounting seat 5a provided on the scavenging passage cover 5 at two locations by screws 7c and 7d, respectively. Since the scavenging passage is constantly cooled by the passage of the mixed fuel during operation, heat transfer from the cylinder 1 to the mounting seat 5a can be suppressed. On one side of the cylinder 1, the combustion chamber 1c, the scavenging path 1e, the scavenging path cover 5, the mounting seat 5a, and the ignition coil 2 are arranged in this order along the crank axis direction. In the crank axis view, at least a part thereof is overlapped.

  A packing member 9 is provided between the scavenging path cover 5 and the cylinder 1 to ensure confidentiality as in the prior art. As a result, the packing member 9 is located between the cylinder 1 and the scavenging path cover 5. Therefore, it is not necessary to dispose the heat insulating member used in the prior art between the ignition coil 2 and the mounting seat 5a. The base material of the packing member 9 is well known, and for example, metallic or rubber can be used.

  According to the above configuration, it is possible to eliminate the heat insulating member 8b used in the prior art by causing the packing member 9 disposed between the scavenging passage cover 5 and the cylinder 1 to function as a heat insulating member. Therefore, it becomes possible to improve productivity and reduce costs. Furthermore, in the engine provided with the scavenging passage cover 5, the degree of freedom of the attachment position of the ignition coil 2 can be improved.

  As mentioned above, although demonstrated based on embodiment which shows this invention, this invention is not limited to the above-mentioned form, A various change is possible within the range which does not deviate from the meaning. For example, the scavenging passage cover 5 is provided with a plurality of mounting seats and the ignition coil 2 is provided in the scavenging passage cover 5 by further contrivances such as narrowing the mounting hole pitch of the ignition coil 2 and enlarging the scavenging passage cover 5. By fixing only with the mounting seat, the mounting seat 1a of the cylinder 1 can be eliminated and the heat insulating members 8a and 8b can be completely removed.

  In the present application, the example in which the two-cycle engine is applied to the blower has been described. However, the present invention can be similarly applied to other portable tools using a small engine.

1: cylinder, 2: ignition coil, 3: magnet rotor, 4: ignition plug, 5: scavenging path cover, 6: scavenging path cover, 7: screw, 8: heat insulating member, 9: packing member, 10: piston, 11 : Connecting rod, 12: crankshaft, 13: crank chamber

Claims (6)

An engine body having a crank chamber and a combustion chamber, in which a scavenging passage inlet opened in the crank chamber and a scavenging passage outlet opened in the combustion chamber are formed;
A scavenging passage cover that covers a part of the engine body including the scavenging passage inlet and the scavenging passage outlet and forms a scavenging passage;
A drive output shaft rotatably supported by the crankcase and connected to a magnet rotor;
An ignition coil disposed adjacent to the magnet rotor and generating electric power by rotating the magnet rotor and supplying electric power to the spark plug;
The engine body is formed with a first mounting seat protruding in the axial direction of the drive output shaft, and the scavenging passage cover is formed with a second mounting seat protruding in the axial direction of the drive output shaft. ,
The two-stroke engine, wherein the ignition coil is mounted across the first mounting seat and the second mounting seat .   The two-stroke engine according to claim 1, wherein a heat insulating member is interposed between the scavenging passage cover and the engine body.   The two-stroke engine according to claim 2, wherein the heat insulating member is configured as a seal member that seals between the scavenging passage cover and the engine body. The two-cycle according to any one of claims 1 to 3 , wherein the ignition coil is provided at a position overlapping the scavenging path cover in the axial direction of the drive output shaft. engine.   The two-stroke engine according to any one of claims 1 to 4, wherein the ignition coil is attached adjacent to the scavenging passage of the scavenging passage cover. The two-cycle engine according to any one of claims 1 to 5 , comprising:
A portable work machine characterized by that.