JP2015098815A - Engine and engine working machine - Google Patents

Abstract

An engine and an engine working machine capable of efficiently cooling a cylinder block over the entire circumference are provided.
An engine (1) that cools a cylinder block (12) with an air flow formed by a cooling fan (31) attached to one end of a crankshaft (19), and a planetary (rotation direction changing mechanism) at the other end of the crankshaft (19). An assist fan 50 that is attached via the gear mechanism 40 and cools the cylinder block 12 with the airflow that is formed is provided.
[Selection] Figure 2

Description

  The present invention relates to an air-cooled engine and engine working machines such as a brush cutter, a chain saw, and a blower equipped with the engine.

  Generally, an air-cooled engine cools a cylinder block by guiding an air flow formed by a cooling fan attached to one end of a crankshaft to the cylinder block. (For example, refer to Patent Document 1).

JP 2011-74874 A

  However, in the prior art, the air flow formed by the cooling fan is from one side of the cylinder block to which the cooling fan is attached to both sides, and from the other side to which the cooling fan is not attached. Therefore, the cooling efficiency of the downstream surface (especially the other surface side where the cooling fan is not attached) is lowered, and the cylinder block can be efficiently cooled over the entire circumference. There was a problem that it was not possible.

  This invention is made in view of the above situations, Comprising: It aims at solving the said subject and providing the engine and engine working machine which can cool a cylinder block efficiently over a perimeter. To do.

The engine of the present invention is an engine that cools a cylinder block with an air flow formed by a cooling fan attached to one end of a crankshaft, and is attached to the other end of the crankshaft via a rotation direction conversion mechanism. And an assist fan that cools the cylinder block with an air flow to be formed.
Furthermore, in the engine of the present invention, the cooling fan and the assist fan may be centrifugal fans.
Further, in the engine of the present invention, the air flow formed by the cooling fan is mainly an air flow from one side of the cylinder block on which the cooling fan is provided to one side, and the cylinder block While cooling one side and one side, the air flow formed by the assist fan is mainly an air flow from the other side of the cylinder block where the assist fan is provided to the other side, The other side and the other side of the cylinder block may be cooled.
Further, in the engine of the present invention, a muffler is provided on one side of the cylinder block that cools the airflow formed by the cooling fan, and the airflow formed by the assist fan cools. A vaporizer may be provided on the other side surface of the cylinder block.
Furthermore, in the engine of the present invention, the rotation direction conversion mechanism may be a planetary gear mechanism that decelerates the rotation of the crankshaft.
Furthermore, in the engine of the present invention, a recoil starter may be attached to the other end of the crankshaft via the planetary gear mechanism.
Moreover, the engine working machine of this invention is equipped with the above-mentioned engine.

  According to the present invention, the cylinder block is cooled also from the other surface side to which the assist fan is attached by the air flow formed by the assist fan attached to the other end of the crankshaft via the rotation direction conversion mechanism. Therefore, there is an effect that the cylinder block can be efficiently cooled over the entire circumference.

It is a figure showing an engine working machine carrying an embodiment of an engine concerning the present invention. It is sectional drawing of the engine shown in FIG. It is the figure which looked at the engine shown in FIG. 1 from the rear end side. It is explanatory drawing for demonstrating the airflow formed with the cooling fan and assist fan which are shown in FIG. It is a figure which shows the structure of the planetary gear mechanism shown in FIG. It is a figure showing a compressor carrying an embodiment of an engine concerning the present invention.

Next, embodiments of the present invention will be specifically described with reference to the drawings.
FIG. 1 shows an engine work machine 2 equipped with an engine 1 of the present embodiment. The engine work machine 2 transmits rotational power from the engine 1 to a tip tool (not shown) (rotary blade, chain saw, cut saw, etc.) on the front end via a drive shaft 3a that is a power transmission means built in the operation rod 3. Drive the tool.

  The operation rod 3 is a long pipe made of aluminum or the like, and is engaged with an operation handle 4 for an operator to hold the engine work machine 2 and perform an operation, and a throttle wire for operating a fuel supply mechanism. A throttle lever 5 is attached.

  The engine 1 is attached to the rear end of the operation rod 3. The engine 1 is an air-cooled engine, and as shown in FIG. 2, a cylinder head 11 is formed integrally with an upper part of a cylinder block 12, and a crankcase 13 is attached to the lower part of the cylinder block 12.

  Cooling fins 14 for cooling the engine 1 are formed around the cylinder block 12, and in the cylinder (cylinder bore) 15 of the cylinder block 12, the piston 16 positioned at the top dead center in FIG. Moves up and down (up and down direction in FIG. 2). The piston 16 is connected via a piston pin 17 and a connecting rod 18 to a crankshaft 19 that is rotatably supported in the crank chamber 13a of the crankcase 13.

  A magnet rotor 20 having a magnet attached to a rotating side surface is coupled to the front end portion of the crankshaft 19 so as to be integrally rotatable with the crankshaft 19. A clutch mechanism 21 is connected to the magnet rotor 20, and the clutch mechanism 21 transmits the rotational power of the engine 1 to the output shaft 22. The output shaft 22 is connected to a drive shaft 3 a built in the operation rod 3, and drives a tip tool attached to the front end of the operation rod 3.

  Referring to FIG. 3, a carburetor 23 is attached to the left side of the engine 1, that is, the left side toward the front in the axial direction of the crankshaft 19. A fuel tank 24 that stores liquid fuel such as gasoline is supported by a stand 25 and is arranged to extend from the lower side of the carburetor 23 to the lower side of the engine 1. The liquid fuel stored in the fuel tank 24 is supplied from the fuel tank 24 to the carburetor 23 as the piston 16 rises, and air and liquid fuel are mixed in the carburetor 23 and supplied to the cylinder 15 as an air-fuel mixture. Is done.

  Referring to FIG. 2, an ignition coil 26 is attached to the front side of the cylinder block 12, and a stator of the ignition coil 26 is opposed to the magnet rotor 20 with a predetermined interval. The ignition coil 26 is connected to a spark plug 28 through a plug cord 27. The high-voltage current generated by the magnet rotor 20 and the ignition coil 26 is energized to the spark plug 28 through the plug cord 27, and the air-fuel mixture supplied into the cylinder 15 is combusted by the ignition of the spark plug 28. Thereby, piston 16 is pushed down, rotational power is transmitted to output shaft 22 via piston pin 17, connecting rod 18, and crankshaft 19, and a tip tool is driven.

  As shown in FIG. 3, a muffler 29 is connected to the right side of the engine 1, that is, to the right side in the axial direction of the crankshaft 19, and exhaust gas (exhaust gas) is discharged to the outside through the muffler 29. Is done. Reference numeral 30 denotes a muffler cover that houses the muffler 29.

  The magnet rotor 20 is integrally formed with a cooling fan 31 for cooling the engine 1. The cooling fan 31 is a centrifugal fan. As shown in FIG. 4, a volute portion 32 that rectifies the air flow generated by the cooling fan 31 and guides it to the front side of the cylinder block 12 is provided outside the cooling fan 31 in the radial direction. FIG. 4 is a view of the engine 1 as viewed from above. In the present embodiment, the crankshaft 19 (cooling fan 31) is rotated clockwise toward the front. Accordingly, the air taken in from the front side by the cooling fan 31 is guided upward through the left side of the cooling fan 31 by the volute portion 32, that is, toward the front in the axial direction of the crankshaft 19, and is shown in FIG. As indicated by the arrow A, the air flow from the front side of the cylinder block 12 provided with the cooling fan 31 to the right side of the cylinder block 12 provided with the muffler 29 cools the front side and right side of the cylinder block 12. .

  An assist fan 50 for cooling the engine 1 and a recoil starter 60 for starting the engine 1 are attached to the rear end portion of the crankshaft 19 via the planetary gear mechanism 40.

  As shown in FIG. 5, the planetary gear mechanism 40 includes an internal gear 41 connected to the rear end side of the crankshaft 19, a sun gear 43 formed on a shaft 42 rotatably supported by a ball bearing, It is composed of two planetary gears 44 that mesh with the internal gear 41 and the sun gear 43. 5A is an exploded perspective view of the planetary gear mechanism 40, and FIG. 5B is a perspective view of the planetary gear mechanism 40. The shaft 42 is press-fitted into the center hole 51 of the assist fan 50, and the planetary gear 44 is attached to the stud 46 of the cam follower 45 into which the assist fan 50 is press-fitted. Therefore, the assist fan 50 moves in the direction opposite to the rotation direction of the internal gear 41 connected to the crankshaft 19 (cooling fan 31) indicated by the arrow C in FIG. It is rotated clockwise.

  The assist fan 50 is a centrifugal fan. As shown in FIG. 4, a volute portion 52 that rectifies the air flow generated by the assist fan 50 and guides it to the rear side of the cylinder block 12 is provided outside the assist fan 50 in the radial direction. The air taken in from the rear side by the assist fan 50 is guided upward by the volute portion 52 through the right side of the assist fan 50, that is, toward the front in the axial direction of the crankshaft 19 and through the right side. As described above, air flows from the rear side of the cylinder block 12 where the assist fan 50 is provided to the left side of the cylinder block 12 where the carburetor 23 is provided, and the rear side and the left side of the cylinder block 12 are cooled. Thereby, the temperature rise of the cylinder temperature of the cylinder block 12, especially the back side in which the recoil starter 60 is provided can be reduced. Since the assist fan 50 is independent of the magnet rotor 20 and does not affect the timing of energizing the spark plug 28, it is possible to generate power by attaching a plurality of magnets to the rotating side surface. It is possible to generate electric power necessary for driving a desired additional device such as an electromagnetic valve even in a state where the rotational speed is relatively low.

  The recoil starter 60 is attached to the shaft 42, and the planetary gear mechanism 40 is installed between the recoil starter 60 and the crankshaft 19. Therefore, since the rotational torque transmitted from the recoil starter 60 to the crankshaft 19 can be easily increased by changing the specifications of the gear ratio of the planetary gear mechanism 40, the recoil starter 60 can be adapted to each displacement. The pulling load of the starter 60 can be reduced. Thereby, the startability of the engine 1 can be significantly improved.

As described above, the present embodiment is an engine 1 that cools the cylinder block 12 with the airflow formed by the cooling fan 31 attached to one end of the crankshaft 19. An assist fan 50 that is attached to the end via a planetary gear mechanism 40 that is a rotation direction changing mechanism and cools the cylinder block 12 with the airflow that is formed is provided.
With this configuration, the cylinder block 12 can be cooled from the other surface side to which the assist fan 50 is attached. Therefore, the cylinder block 12 can be efficiently cooled over the entire circumference.

Further, according to the present embodiment, the cooling fan 31 and the assist fan 50 are centrifugal fans, and the air flow formed by the cooling fan 31 is on one side of the cylinder block 12 where the cooling fan 31 is provided. The air flow from one side to the other side of the cylinder block 12 cools one side and one side of the cylinder block 12, and the air flow formed by the assist fan 50 is different from that of the cylinder block 12 provided with the assist fan 50. The airflow is from the direction side to the other side surface, and the other side surface and the other side surface of the cylinder block 12 are cooled.
With this configuration, the air flow formed by the assist fan 19 can be guided to the cylinder block 12 without colliding with the air flow formed by the cooling fan 31.

Further, according to the present embodiment, the rotation direction conversion mechanism is the planetary gear mechanism 40 that decelerates the rotation of the crankshaft 19, and one side of the cylinder block 12 that is cooled by the air flow formed by the cooling fan 31. In addition, a muffler 29 is provided, and a vaporizer 23 is provided on the other side of the cylinder block 12 where the air flow formed by the assist fan 50 is cooled.
With this configuration, it is possible to increase the cooling efficiency by supplying a strong air flow to one side of the cylinder block 12 where the muffler 29 with a large amount of heat is provided, and efficiently cool the cylinder block 12 over the entire circumference. can do.
In the case where it is desired to cool the muffler 29 with particular emphasis, both the air flow by the assist fan 19 and the cooling fan 31 may be directed to the muffler 29 side.

Further, according to the present embodiment, the recoil starter 60 is attached to the other end of the crankshaft via the planetary gear mechanism 40.
With this configuration, the rotational torque transmitted from the recoil starter 60 to the crankshaft 19 can be easily increased by changing the specifications of the gear ratio of the planetary gear mechanism 40, and the pulling load of the recoil starter 60 is reduced. It becomes possible.

The present invention has been described based on this embodiment. This embodiment is an exemplification, and it will be understood by those skilled in the art that various modifications can be made to combinations of these components and the like, and such modifications are within the scope of the present invention.
For example, in the present embodiment, the example in which the engine 1 is mounted on the engine working machine 2 such as a brush cutter having the operation rod 3 has been described. It may be installed.
Furthermore, the engine 1 according to the present invention is not limited to the portable engine work machine 2 but may be mounted on the stationary engine work machine 2 as in the compressor 70 shown in FIG. Also in the compressor 70, the cooling fan 31 and the assist fan 50 are provided with the engine 1 sandwiched in the axial direction of the crankshaft, so that the temperature increase on the right side of the drawing, which is the back side when viewed from the cooling fan 31 side in the engine 1, can be efficiently performed. Can be reduced.

DESCRIPTION OF SYMBOLS 1 Engine 2 Engine working machine 3 Operation rod 3a Drive shaft 4 Operation handle 5 Throttle lever 11 Cylinder head 12 Cylinder block 13 Crankcase 13a Crank chamber 14 Cooling fin 15 Cylinder 16 Piston 17 Piston pin 18 Connecting rod 19 Crankshaft 20 Magnet rotor 21 Clutch Mechanism 22 Output shaft 23 Vaporizer 24 Fuel tank 25 Stand 26 Ignition coil 27 Plug cord 28 Spark plug 29 Muffler 30 Muffler cover 31 Cooling fan 32 Volute part 40 Planetary gear mechanism 41 Internal gear 42 Shaft 43 Sun gear 44 Planetary gear 45 Cam follower 46 Stud 50 Assist fan 51 Center hole 52 Volute 60 Recoil starter 70 Compressor

Claims (7)

An engine that cools a cylinder block with an air flow formed by a cooling fan attached to one end of a crankshaft,
An engine comprising an assist fan attached to the other end of the crankshaft via a rotation direction changing mechanism and cooling the cylinder block with an air flow formed.   The engine according to claim 1, wherein the cooling fan and the assist fan are centrifugal fans. The air flow formed by the cooling fan is mainly an air flow from one side of the cylinder block on which the cooling fan is provided to one side, and the one side and one side of the cylinder block are With cooling,
The air flow formed by the assist fan is mainly an air flow from the other side of the cylinder block where the assist fan is provided to the other side, and the other side and the other side of the cylinder block are The engine according to claim 1, wherein the engine is cooled. A muffler is provided on one side of the cylinder block that cools the airflow formed by the cooling fan,
The engine according to claim 3, wherein a carburetor is provided on the other side of the cylinder block that is cooled by an air flow formed by the assist fan.   The engine according to any one of claims 1 to 4, wherein the rotation direction conversion mechanism is a planetary gear mechanism that decelerates rotation of the crankshaft.   The engine according to claim 5, wherein a recoil starter is attached to the other end of the crankshaft via the planetary gear mechanism.   An engine work machine comprising the engine according to claim 1.

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