JP5387305B2 - Diaphragm carburetor gasket, 4-cycle engine including the same, and engine tool including the 4-cycle engine - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a diaphragm type carburetor gasket, and more particularly to a diaphragm type carburetor gasket suitable for portable engine tools such as a brush cutter, a chain saw, and a blower equipped with a 4-cycle engine.

  In portable engine tools such as a brush cutter and a chain saw, an operator often performs work by tilting the engine tool in various directions, and the engine needs to operate stably even in the tilted state. For this reason, a two-cycle engine that can lubricate the inside of the engine without being influenced by the attitude of the engine by mixing lubricating oil with fuel and supplying the inside of the engine is often used. In many cases, a diaphragm type carburetor is used that can drive the fuel pump of the carburetor using the pressure fluctuation of the carburetor and supply fuel without being influenced by the attitude of the engine. Further, as shown in Patent Document 1, the engine and the carburetor are attached via an insulator and gaskets attached to both ends thereof.

Japanese Utility Model Publication No. 58-154850

  By the way, since a 2-cycle engine has a large amount of nitrogen oxides and hydrocarbons in exhaust gas, in recent years, an engine tool equipped with a 4-cycle engine with cleaner exhaust gas has appeared. However, in the 4-cycle engine, the volume in the crankcase is large and the pressure fluctuation is small compared to the 2-cycle engine. For this reason, it becomes a subject how to take out the pressure fluctuation for driving the fuel pump of a diaphragm type carburetor.

  The present invention has been made in view of the above problems, and can transmit sufficient pressure fluctuations to the diaphragm type carburetor, and facilitate the assembly work of the engine and the carburetor with a simple configuration to reduce the manufacturing cost. An object of the present invention is to provide a diaphragm type carburetor gasket.

In order to achieve the above object, a diaphragm type carburetor gasket according to a first aspect of the present invention includes a diaphragm type carburetor having an intake passage and a diaphragm driving pulse hole, and an insulator connected to an intake port of the engine. Between the intake passage opening provided at a position corresponding to the intake passage of the carburetor, and a pulse pressure communication connecting the intake passage opening and the pulse hole. possess a passageway, the pulse pressure communication passage has a first connecting portion connected to the intake passage opening at one end, a second connecting portion provided at a position corresponding to the pulse hole at the other end The first connection portion is connected to an outer peripheral edge of the intake passage opening, and the pulse pressure communication passage is connected to the intake passage from the first connection portion. Comprising a extending portion extending toward the outer side of the opening, and the direction changing section for bending the pulse pressure communication passage connected to the extending portion, and wherein the.

Further, the intake passage opening is preferably have a substantially circular flow cross-section.

  Further, the second connection portion is formed from the first connection portion in the radial direction of the intake passage opening passing through the first connection portion and the center of the intake passage opening. May be located on the side toward the center.

  The second connection portion may be positioned beyond the intake passage opening in a radial direction of the intake passage opening passing through the first connection portion and the center of the intake passage opening.

  Further, the pulse pressure communication passage may be a through groove penetrating from a surface facing the carburetor to a surface facing the insulator.

  Further, the pulse pressure communication passage may be formed in a concave groove shape on a surface facing the carburetor.

  Furthermore, it is preferable that the insulator is connected to the intake port via an insulator gasket, and the thickness of the diaphragm carburetor gasket is larger than the thickness of the insulator gasket.

  A four-cycle engine according to a second aspect of the present invention is characterized in that the above-described diaphragm type carburetor gasket is provided between the carburetor and the insulator.

  Further, the present invention is a four-cycle engine provided with the above-described diaphragm type carburetor gasket between the carburetor and the insulator, wherein the first connection portion is used for the intake passage in the cylinder axial direction of the four-cycle engine. The center of the opening is preferably located on the direction side from the bottom dead center to the top dead center of the 4-cycle engine.

  The first connecting portion includes a tank for storing fuel, an intake passage provided in the carburetor, through which an air-fuel mixture containing the fuel flows, and a fuel supply portion that supplies the fuel into the intake passage. Is preferably located on the opposite side of the fuel supply section with respect to the center of the intake passage.

In the above-described four-cycle engine, it is preferable that the second connecting portion is located on the side of the first connecting portion toward the bottom dead center from the top dead center.

Further, the first connection portion before SL is connected to the outer peripheral edge of the front Symbol the intake passage opening that the distance from the center of the intake passage opening becomes maximum in a direction toward the top dead center from the bottom dead center May be.

  An engine tool according to a third aspect of the present invention includes the above-described four-cycle engine.

  According to the present invention, a sufficient pressure fluctuation can be transmitted to the diaphragm carburetor, and the assembly work of the engine and the carburetor can be facilitated with a simple configuration, thereby reducing the manufacturing cost.

The figure which shows the brush cutter carrying the 4 cycle engine which concerns on this invention. The expanded sectional view of the engine part of FIG. III-III sectional view taken on the line of FIG. IV-IV sectional view taken on the line of FIG. VV sectional view taken on the line of FIG. FIG. 6 is an enlarged cross-sectional view of the crank chamber portion of FIG. 5. VII-VII line sectional drawing of FIG. VIII-VIII sectional view taken on the line in FIG. IX-IX sectional view taken on the line of FIG. XX sectional drawing of the muffler part of FIG. The enlarged view of the carburetor part of FIG. Exploded view of parts between engine and carburetor. The front view seen from the engine side of the carburetor. The front view seen from the engine side of the gasket of this invention. XV-XV sectional view taken on the line of FIG. The figure corresponding to FIG. 6 of the modification of the overhead valve type engine which concerns on this invention. The figure corresponding to FIG. 15 of the modification of the gasket which concerns on this invention.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows a brush cutter 1001 equipped with a four-cycle engine 1 (hereinafter referred to as an engine) according to an embodiment of the present invention. In the brush cutter 1001, the rotary blade 1003 is attached to the tip of the operating rod 1002, and the engine 1 is attached to the rear end of the operating rod 1002. The output of the engine 1 is supplied to the rotary blade 1003 through a drive shaft that is inserted into the operation rod 1002. The operator operates the brush cutter 1001 by holding the handle 1004 attached to the operation rod 1002. In a normal upright state in which an operator grips the brush cutter 1001, the engine 1 is attached to the operation rod 1002 so that the axial direction of a cylinder (not shown) of the engine 1 faces the vertical direction. In addition, the rotating blade 1003 in operation is configured to rotate counterclockwise as viewed from above, as indicated by an arrow 1010. Then, when the operator holds the brush cutter 1001 so that the operating rod 1002 is positioned on the right side of the operator's body and moves the rotary blade 1003 to the left as indicated by an arrow 1020, the operator Cut the grass.

  As shown in FIG. 2, the engine 1 is an air-cooled OHV engine, a cylinder head 2 is integrally formed on the upper part of the cylinder block 3, and a crankcase 4 is attached to the lower part of the cylinder block 3. Cooling fins 31 for cooling the engine 1 are formed around the cylinder block 3, and in the cylinder (cylinder bore) 5 of the cylinder block 3, the piston 6 positioned at the top dead center in FIG. 7 moves up and down (vertical direction in FIG. 2). The piston 6 is connected via a piston pin 8 and a connecting rod 9 to a crankshaft 10 having a crank weight 101 rotatably supported in a crank chamber 41 of the crankcase 4. The inside of the crankcase 4 is partitioned into a crank chamber 41 and an oil chamber 42 provided adjacent to the lower portion of the crank chamber 41. An oil suction port 47 is provided in the oil chamber 42, and the oil suction port 47 is connected to an oil pump (not shown). The oil pump sucks up the oil accumulated in the oil chamber 42 from the oil suction port 47 and discharges the oil into the crank chamber 41 through an oil projection hole (not shown) formed in the camshaft (not shown). The oil that has been used becomes oil mist and scatters in the crank chamber.

  A starter mechanism 11 for starting the engine 1 is attached to one end portion of the crankshaft 10, and a flywheel magneto 12 is attached to the other end portion. The flywheel magneto 12 is integrally formed with a cooling fan 32 for cooling the engine 1. A clutch mechanism 13 is connected to the flywheel magneto 12. The clutch mechanism 13 transmits the output of the engine 1 to a drive shaft (output shaft) 14 to drive the rotary blade 1003. A cam drive gear 15 for driving a camshaft (not shown) is attached to the crankshaft 10.

  The cylinder head 2 is formed with an intake port 21 for supplying an air-fuel mixture to the combustion chamber 20 and an exhaust port 22 for discharging combustion gas from the combustion chamber 20. The intake port 21 is opened and closed by an intake valve 18. Opened and closed by the exhaust valve 19. A valve mechanism chamber 50 is provided in the upper part of the cylinder head 2. The valve mechanism chamber 50 accommodates an intake rocker arm 16 and an exhaust rocker arm 17 that open and close the intake valve 18 and the exhaust valve 19, respectively. .

  As shown in FIG. 3, a carburetor 24 that supplies an air-fuel mixture to the engine 1 via an insulator 23 connected to the intake port 21 is attached to the left side portion of the cylinder head 2. An air cleaner 70 is attached upstream of the carburetor 24 (left side in FIG. 3). A connection passage 52 is provided between the air cleaner 70 and the valve mechanism chamber 50 to allow the blow-by gas flowing into the valve mechanism chamber 50 to return to the air cleaner 70. A muffler 25 connected to the exhaust port 22 is attached to the right side of the cylinder head 2. Further, a spark plug 53 is attached to the cylinder head 2.

  A camshaft 60 having a driven gear 61 that meshes with the cam drive gear 15 of the crankshaft 10 is provided in the crank chamber 41 of the crankcase 4. An intake cam (not shown) and an exhaust cam (not shown) are formed on the camshaft 60. The intake cam and the exhaust cam respectively drive an intake push rod (not shown) and an exhaust push rod 51 via a tappet (not shown). The intake push rod and the exhaust push rod 51 drive the intake rocker arm 16 and the exhaust rocker arm 17 provided in the valve operating mechanism chamber 50, respectively. The intake rocker arm 16 and the exhaust rocker arm 17 opens and closes the intake valve 18 and the exhaust valve 19, respectively.

  As shown in FIG. 3, the crank chamber 41 and the oil chamber 42 of the crankcase 4 include a horizontal partition wall (first partition wall) 43 extending in the left-right direction and a vertical partition wall (second partition wall) extending in the vertical direction. 44). The vertical partition wall 44 is located on the left side of the crankshaft 10 in FIG. 3 and extends downward from the upper left inner wall of the crankcase 4 beyond the axis 26 of the crankshaft 10. Further, the horizontal partition wall 43 is located on the lower side of the crankshaft 10 and extends beyond the axis 26 of the crankshaft 10 toward the left from the inner wall on the lower right side of the crankcase 4. The left end 431 of the horizontal partition wall 43 is located below the lower end 441 of the vertical partition wall 44 or to the left of the lower end 441 in the left-right direction in FIG. Moreover, the horizontal direction partition wall 43 is descend | falling gradually from the horizontal surface as it goes to the left, and the left side edge part 431 is located in the lowest part. The lower end portion 441 of the vertical partition wall 44 and the left end portion 431 of the horizontal partition wall 43 are separated from each other, and a communication passage 45 that connects the crank chamber 41 and the oil chamber 42 is formed by this separated portion. Yes. As shown in FIG. 3, the vertical partition wall 44 and the horizontal partition wall 43 are substantially V-shaped in cross section, and communicate with a substantially V-shaped top portion located on the lower left side of the crankshaft 10. 45 is formed. The oil chamber 42 includes a first oil chamber 421 formed by the horizontal partition wall 43 and the outer wall of the crankcase 4, and a second oil chamber formed by the vertical partition wall 44 and the outer wall of the crankcase 4. 422.

  The cylinder block 3 is provided with a first breather passage (second passage) 54 extending from the valve mechanism chamber 50 toward the crankcase 4 along the direction of the cylinder axis 7, and the first breather passage 54 is provided with the valve mechanism. A valve mechanism chamber side opening 541 provided in the chamber 50 is provided. The intake push rod and the exhaust push rod 51 pass through the first breather passage 54. As shown in FIG. 4, the first breather passage 54 is formed in a connection portion between the cylinder block 3 and the crankcase 4 in a second breather passage (first passage) 55 communicating with the crank chamber 41 of the crankcase 4. The third breather passage (third passage) 56 is connected. It should be noted that the first breather passage 54 and the second breather passage 55 are disposed such that the opening positions of the third breather passage 56 are offset when viewed in the direction of the cylinder axis 7. The third breather passage 56 is provided with a partition wall 561 that extends in the direction of the cylinder axis 7 and surrounds the periphery of the second breather passage 55 with the upper side in FIG. As shown in FIG. 5, the third breather passage 56 has a cylinder-side recess 564 that is concave upward, and a ceiling wall 562 is located above the second breather passage 55 in the direction of the cylinder axis 7. Is provided. Further, a recess (recess) 563 is formed on the crankcase 4 side of the third breather passage 56, and the recess 563 is a part of the first breather passage 54 as viewed in the direction of the cylinder axis 7 as shown in FIG. It is arranged to overlap.

  As shown in FIG. 5, the second breather passage 55 extends from the third breather passage 56 toward the crank chamber 41 along the direction of the cylinder axis 7. The second breather passage 55 communicates with the crank chamber 41 through a crank chamber-side opening 551 provided to face the rotation surface 611 on the right side of the driven gear 61 of the camshaft 60 in the crank chamber 41.

  As shown in FIG. 6, an annular recess 612 is formed on the rotation surface 611 of the driven gear 61. Further, the crank chamber side opening 551 is formed at the left end in FIGS. 5 and 6 of the cylindrical projecting wall 552 projecting toward the recess 612 of the driven gear 61. The crank chamber side opening 551 is in the recess 612 in the direction of the axis 62 of the camshaft 60, that is, the left end of the protruding wall 552 forming the crank chamber side opening 551 is the rightmost side of the rotation surface 611 of the driven gear 61. Located on the left side of the side surface. As shown in FIG. 7, the crank chamber side opening 551 is located inside the annular recess 612 located inside the root circle 613 of the driven gear 61 when the camshaft 60 is viewed in the direction of the axis 62.

  As shown in FIG. 8, an oil pump 63 is connected to the left end of the camshaft 60. The oil pump 63 is a trochoid pump and includes an outer rotor 631 and an inner rotor 632. An oil suction port 47 of the oil chamber 42 is connected to a suction port (not shown) of the oil pump 63 through an oil suction passage 471, and a recess 563 of the third breather passage 56 is connected to an oil return passage 564 (fourth fourth). Connected through a passageway). Further, the discharge port of the oil pump 63 is connected to an oil supply passage 601 that is formed inside the camshaft 60 and extends in the direction of the camshaft shaft 26, and the oil supply passage 601 is a plurality of formed on the outer peripheral surface of the camshaft 60. It is connected to the oil discharge hole 602 and communicates with the crank chamber 41. The oil pump 63 sucks oil accumulated in the oil chamber 42 and the recessed portion 563 of the third breather passage 56 during one rotation of the engine, and the oil is injected into the crank chamber 41 from the oil discharge hole 602 of the rotating camshaft 60. A part of the discharged oil becomes oil mist and scatters in the crank chamber 41.

  As shown in FIG. 9, the cylinder head 2 has a substantially rectangular outer peripheral shape when viewed in the direction of the cylinder axis 7. An opening 27 (combustion chamber side intake opening) on the combustion chamber 20 side of the intake port 21 of the cylinder head 2 and an opening 28 (combustion chamber side exhaust opening) on the combustion chamber 20 side of the exhaust port 22 are viewed in the direction of the cylinder axis 7. The combustion chamber side intake openings 27 are arranged side by side so as to be positioned on the flywheel magneto 12 side substantially parallel to the axis 26 of the crankshaft 10. Similarly, an intake valve 18 and an exhaust valve 19 that open and close the combustion chamber side intake opening 27 and the combustion chamber side exhaust opening 28 are also arranged substantially parallel to the axis 26 of the crankshaft 10. A muffler 25 is attached to an upper side surface (one side) in FIG. 9 that is substantially parallel to the axis 26 of the crankshaft 10 of the cylinder head 2 via a wind guide plate 29. Similarly, the lower side surface (the other side) ) Is provided with a carburetor 24 via an air guide plate 30 and an insulator 23.

  As shown in FIG. 9, when viewed from the direction of the cylinder axis 7, the intake port 21 is a direction away from the combustion chamber side intake opening 27 from the axis 26 of the crankshaft 10, and below the carburetor 24 attached via the insulator 23. 9 extends toward the outer peripheral surface (first side) of the cylinder head 2 facing the flywheel magneto 12 in a direction toward the side surface (first direction), that is, toward the lower left in FIG. . The intake port 21 is connected to the insulator 23 through a suction side opening 211 that opens on the lower side surface of the cylinder head 2 in FIG. 9. A carburetor 24 is connected to the insulator 23, and the air-fuel mixture is supplied from the carburetor 24 to the intake port 21 through the communication hole 231 of the insulator 23.

  Further, as shown in FIG. 9, when viewed in the direction of the cylinder axis 7, the exhaust port 22 is a direction away from the combustion chamber side exhaust opening 28 from the axis 26 of the crankshaft 10 and toward the muffler 25 (second direction). ), The distance from the combustion chamber side exhaust opening 28 in the direction of the axis 26 of the crankshaft 10 increases as the distance from the combustion chamber side exhaust opening 28 increases (away from the outer peripheral surface of the cylinder head 2 facing the flywheel magneto 12). That is, it extends toward the upper right in FIG. The exhaust port 22 is connected to the muffler 25 at a discharge side opening 221 located at an end portion on the side surface above the cylinder head 2 on the side away from the flywheel magneto 12.

  The muffler 25 has a substantially flat rectangular parallelepiped shape, and is arranged so that the surface having the maximum area of the muffler 25 faces the upper side surface provided with the discharge side opening 221 of the cylinder head 2. As shown in FIG. 10, an exhaust inflow port 251 is provided in the vicinity of the upper left end portion of the surface of the muffler 25 facing the cylinder head 2 at a position corresponding to the discharge side opening 221 of the cylinder head 2. The exhaust inlet 251 is connected to the discharge side opening 221 with a gasket (not shown) and the air guide plate 29 interposed therebetween. As shown in FIG. 9, the inside of the muffler 25 is divided into a first chamber 253 and a second chamber 254 by a partition wall 252 provided substantially parallel to a surface facing the cylinder head 2. The partition wall 252 is provided with a plurality of connection passages 255 that connect the first chamber 253 and the second chamber 254. As shown in FIG. 10, the connection passage 255 is provided in the vicinity of the lower right end portion of the partition wall 252 so that the distance from the exhaust inlet 251 increases. The second chamber 254 is provided with an exhaust outlet 256 that communicates with the outside. As shown in FIG. 9, the exhaust outlet passage 256 is provided on the side surface on the exhaust inflow port 251 side adjacent to the surface of the muffler 25 facing the cylinder head 2 and extending in the cylinder axis 7 direction, on the right side surface in FIG. 9. As shown in FIG. 10, in the direction of the cylinder axis 7, it is provided at substantially the same position as the connection passage 255 and in the vicinity of the lower end of the side surface.

  As shown in FIG. 9, the cylinder head 2 is disposed between the combustion chamber side intake opening 27 and the combustion chamber side exhaust opening 28 in the direction of the axis 26 of the crankshaft 10 and in a direction perpendicular to the axis 26 of the crankshaft 10. , An ignition plug mounting hole 33 for providing an ignition plug (not shown) is formed on the carburetor 24 side from the combustion chamber side intake opening 27 or the combustion chamber side exhaust opening 28, that is, on the right side of the intake port 21 in FIG. ing.

  As shown in FIGS. 11 and 12, between the carburetor 24 and the cylinder head 2, from the carburetor 24 side, a first gasket 126 (diaphragm carburetor gasket), a wire guide 127, a second gasket 128, and an insulator 23 are provided. The third gasket 130, the air guide plate 131, and the fourth gasket 132 are provided. The material of the first gasket 126 is a non-asbestos sheet, and the thickness is about 0.8 mm. Further, the materials of the second gasket 128, the third gasket 130, and the fourth gasket 132 are all non-asbestos sheets as in the first gasket 126, but the thickness is 0.3 mm, which is more than that of the first gasket 126. It is getting thinner. Each gasket is not limited to a non-asbestos sheet, and may be a metal gasket.

  The insulator 23 is attached to the cylinder head 2 together with the third gasket 130, the air guide plate 131, and the fourth gasket 132 by an attachment screw 129. Further, the carburetor 24 is attached to the insulator 23 together with the first gasket 126, the wire guide 127, and the second gasket 128 by a mounting screw (not shown).

  As shown in FIG. 13, on the surface to which the first gasket 126 of the carburetor 24 is attached, an intake passage 241 having a substantially circular cross section through which the air-fuel mixture flows, and the carburetor 24 located obliquely to the lower right of the intake passage 241 in FIG. In order to drive a diaphragm (not shown) for sending fuel to the diaphragm, a pulse hole 242 for transmitting pressure fluctuation to the diaphragm and a mounting hole 243 through which a mounting screw for mounting the carburetor 24 to the insulator 23 pass are formed. In a state where the carburetor 24 is attached to the engine 1, the pulse hole 242 is located below the intake passage 241 when the direction from the bottom dead center to the top dead center in the cylinder axis direction is set upward.

  Further, as shown in FIG. 14, the first gasket 126 attached to the carburetor 24 is positioned so as to correspond to the intake passage 241 of the carburetor 24 at the time of attachment, and the intake passage opening 261 having a substantially circular cross section through which the air-fuel mixture flows. And a mounting hole 263 through which a mounting screw for mounting the carburetor 24 to the insulator 23 passes, and a first connection portion 264 that connects to the intake passage opening 261 and is provided at a position corresponding to the pulse hole 242 of the carburetor 24 during mounting. A pulse pressure communication passage 267 that terminates at the pulse communication hole (second connection portion) 262 and connects the intake passage opening 261 and the pulse communication hole 262 is formed. The first connecting portion 264 of the pulse pressure communication passage 267 is connected to the upper side, specifically, the upper end of the intake passage opening 261 in FIG. The pulse pressure communication passage 267 extends from the first connection portion 264 to the outside in the radial direction of the intake passage opening 261 and to the extension portion 265 and extends upward in FIG. The direction change part 266 which curves the extension direction of the pulse pressure communication path 267 toward the lower right side is comprised. As shown in FIGS. 14 and 15, the intake passage opening 261, the mounting hole 263, the pulse communication hole 262, and the pulse pressure communication passage 267 of the first gasket 126 all penetrate in the thickness direction of the first gasket 126. Is formed. The direction changing section 266 is connected to the pulse communication hole 262 while maintaining a predetermined distance with respect to the intake passage 241 and maintains insulation from the intake passage 241. As shown in FIG. 15, a fuel supply unit 241 </ b> A for supplying fuel from the fuel tank 70 into the intake passage 241 is located in the intake passage 241. Therefore, the fuel supplied into the intake passage 241 is supplied with the lower side of the intake passage 241 where the fuel supply unit 241A is located darker and the upper side thinner. Further, since the first connection portion 264 of the pulse pressure communication passage 267 is located on the opposite side of the fuel supply portion 241A in the radial direction of the intake passage 241, the first connection portion 264 is less likely to be clogged with fuel. ing.

  According to the engine 1 configured as described above, when the brush cutter 1001 is in the upright state and the engine 1 is operating, of the oil (oil mist) scattered in the crank chamber 41 by the oil pump, The oil adhering to the crankshaft 10 and the crankweight 101 is scattered in the radial direction by the centrifugal force generated by the rotation of the crankshaft 10. The oil splashing upward in FIG. 3 is supplied to the cylinder 5 and the piston 6. On the other hand, the engine 1 rotates clockwise as indicated by an arrow 100, and the vertical partition wall 44 is located on the left side of the crankshaft 10 to which oil scattered in the horizontal direction from the crankshaft 10 tends to adhere. For this reason, the oil scattered in the left direction in FIG. 3 adheres to the vertical partition wall 44 and then falls downward along the vertical partition wall 44 by its own weight. Further, oil that scatters downward or oil that falls due to gravity adheres to the horizontal partition wall 43. And since the horizontal direction partition wall 43 inclines toward the lower left, the oil adhering to the horizontal direction partition wall 43 moves toward the lower left end part 431. The oil that has moved along the vertical partition wall 44 and the horizontal partition wall 43 reaches the communication passage 45 and returns to the oil chamber 42 from the communication passage 45. For this reason, it becomes possible to quickly return excess oil from the crank chamber 41 to the oil chamber 42, it is possible to suppress the oil from being scooped up by the crank weight 101, and to prevent the excess oil from remaining in the crank chamber 41. The oil in the engine 1 can be circulated appropriately. Accordingly, it is possible to suppress excessive supply of oil mist into the valve operating mechanism chamber 50 due to excessive oil remaining in the crank chamber 41. And it is suppressed that the oil mist supplied excessively in the valve operating mechanism chamber 50 is returned to the air cleaner 70 from the connection passage 52 together with the blow-by gas, and oil adheres to the air cleaner 70 and becomes an intake resistance. It is possible to suppress the increase in oil consumption, carbon accumulation in the combustion chamber, and deterioration of the exhaust gas characteristic value due to the oil burning. Further, since the crankcase 4 has a simple structure in which the horizontal partition wall 43 and the vertical partition wall 44 are provided, the above-described effects can be obtained while suppressing the manufacturing cost of the engine 1.

  Further, even when the brush cutter 1001 is tilted from the upright state in FIG. 3 while the engine 1 is rotated clockwise by, for example, about 90 degrees, the oil in the oil chamber 42 is retained by the horizontal partition wall 43. 1 oil chamber 421 can be retained. Further, even when the engine 1 rotates counterclockwise in FIG. 3 to about 90 degrees, for example, the oil in the oil chamber 42 can be retained in the second oil chamber 421 by the vertical partition wall 44. . For this reason, it is easy to provide the horizontal partition wall 43 and the vertical partition wall 44 in the crankcase 4 while suppressing the manufacturing cost, and the oil is within the range of the inclination of the engine 1 assumed during the operation of the brush cutter 1001. The oil in the chamber 42 is always kept in the oil chamber 42, and the backflow of the oil in the oil chamber 42 into the crank chamber 41 can be suppressed, and the oil can be circulated appropriately in the engine 1. Become. Then, excessive supply of oil mist into the valve mechanism chamber 50 is suppressed, and oil adheres to the air cleaner 70 and becomes an intake resistance, or oil burns and increases oil consumption, carbon deposition in the combustion chamber, It becomes possible to suppress the deterioration of the exhaust gas characteristic value.

  Further, in a brush cutter 1001 having a cutting blade 1003 that rotates counterclockwise in a top view as shown in FIG. 1, the brush cutter 1001 is slightly tilted in the direction indicated by an arrow 1030 in FIGS. In many cases, the left end of the object to be cut is left so as not to leave the left end of the object to be cut from the state where the surface is level with the ground. In the brush cutter 1001, the drive shaft 14 of the engine 1 advances from the crankshaft 10 in the direction in which the right-hand screw that rotates in the same direction as the crankshaft 10 when the engine 1 is rotating forward, that is, clockwise as shown in FIG. 2 extends in the left direction in FIG. For this reason, as shown in FIG. 3, in the engine 1 inclined in the direction of the arrow 1030, the inclination angle of the horizontal partition wall 43 becomes closer to the vertical, and the vertical partition wall 44 still has an angle close to the vertical direction. The communication passage 45 is positioned at the lowest vertical portion of the horizontal partition wall 43 and the vertical partition wall 44. For this reason, it becomes possible to return the oil adhering to the vertical partition wall 44 and the horizontal partition wall 43 in the crank chamber 42 to the oil chamber 42 from the communication passage 45 more quickly, and to more appropriately supply the oil in the engine 1. It can be circulated. Therefore, in the posture of the engine 1 that is frequently used, it is further suppressed that excess oil stays in the crank chamber 41, and the same effect as described above can be obtained more effectively.

  In the above-described embodiment, the communication passage 45 is formed by separating the end portions of the horizontal partition wall 43 and the vertical partition wall 44, but the configuration of the communication passage 45 is limited to such a configuration. It is not a thing. For example, the left end 431 of the horizontal partition wall 43 and the lower end of the vertical partition wall 44 may be coupled, and one or a plurality of holes may be formed in the coupling portion to form the communication path. Further, as shown in FIG. 3, the cross section of the horizontal partition wall 43 has a portion that is coaxially curved with the crankshaft 10 at the lower portion of the crankshaft 10, but the engine 1 that is often used is slightly inclined. As long as the oil flows in the state toward the communication passage 45 along the horizontal wall 43, the oil may be formed flat or may have a curved surface partially.

Further, according to the engine 1 configured as described above, the oil mist discharged from the oil discharge hole 602 of the camshaft 60 and scattered in the crank chamber 41 causes the piston 6 to descend and the pressure in the crank chamber 41 to decrease. Rises together with the blow-by gas in the crank chamber 41, flows into the second breather passage 55 from the crank chamber side opening 551 of the second breather passage 55, and the third breather passage 55 is moved upward in the direction of the cylinder axis 7. It flows toward 56. The gas containing oil mist that has flowed into the third part breather passage 56 is changed in the flow direction in the direction perpendicular to the cylinder axis 7 by the partition wall 561 and flows into the first breather passage 54, so that the first breather 54 It flows in the passage 54 toward the valve mechanism chamber side opening 541 and flows into the valve mechanism chamber 50. Further, when the piston 6 rises and the pressure in the crank chamber 41 falls, the oil mist in the valve mechanism chamber 50 flows into the third breather passage 56 through the first breather passage 54. At this time, the flow direction of the oil mist is changed from the vertical direction to the horizontal direction by the partition wall 561 in the third breather passage 56. That is, as shown in FIG. 4, 5, 6, gas containing oil mist flows through the third breather passage 56 as shown by arrows 9. 1 shows a second breather passage 55 in the arrow 9 0 And flows in the first breather passage 54 as indicated by an arrow 92.

  The blow-by gas that has flowed into the valve mechanism chamber 50 returns to the air cleaner 70 through the connection passage 52 and is sent to the combustion chamber 20 again. On the other hand, the oil mist that has flowed into the valve mechanism chamber 50 adheres to the valve mechanism to lubricate the valve mechanism, and the liquefied oil falls in the first breather passage 54 from the valve mechanism chamber side opening 541. Then, it collects in the recess 563 of the third breather passage 56. Then, the oil accumulated in the recess 563 is sucked by the oil pump 63 through the oil return passage 564 and discharged again into the crank chamber 41 from the oil discharge hole 602 of the camshaft 60 again.

  Since the crank chamber side opening 551 into which the oil mist in the crank chamber 41 flows is provided at a position facing the rotation surface 611 of the driven gear 61, the crank chamber side opening 551 is caused by the centrifugal force generated by the rotation of the driven gear 61. The oil mist that flows in can be restricted, that is, the oil mist is less likely to enter the crank chamber side opening 551 by the driven gear 61, so that excessive oil supply to the valve operating chamber 50 and the like can be suppressed. . Since the crank chamber side opening 551 into which the oil mist in the crank chamber 41 flows is located in the annular recess 612 of the driven gear 61, the passage through which the oil mist flows is configured in a labyrinth shape. For this reason, the oil mist in the crank chamber 41 does not easily flow into the crank chamber side opening 551, and the amount of oil mist flowing into the second breather passage 55 can be regulated. Therefore, the amount of oil mist flowing into the valve operating mechanism chamber 50 from the crank chamber 41 is restricted, so that excessive oil mist can be prevented from flowing into the valve operating mechanism chamber 50, and the connecting passage along with the blow-by gas. 52 is suppressed from returning to the air cleaner 70, and oil adheres to the air cleaner 70 to become intake resistance, oil is burned and oil consumption increases, carbon deposition in the combustion chamber, exhaust gas characteristic values It becomes possible to suppress the deterioration of. Further, since the annular recess 612 of the driven gear 61 is formed and the crank chamber side opening 551 is formed as a cylindrical protruding wall 552 protruding toward the recess 612, the manufacturing cost of the engine 1 is reduced. The above-described effects can be obtained while suppressing the above. Furthermore, since the oil discharge hole 602 of the camshaft 60 is located on the left side as shown in FIGS. 5 and 6 from the crank chamber side opening 551, the oil discharged from the oil discharge hole 602 together with the labyrinth-shaped passage described above is It becomes difficult to flow into the crank chamber side opening 551. Therefore, excessive oil mist can be further prevented from flowing into the valve operating mechanism chamber 50, and the above-described effects can be obtained more efficiently.

  Further, part of the oil mist that has flowed through the first breather passage 54 or the second breather passage 55 and reached the third breather passage 56 is offset from the first breather passage 54 and the second breather passage 55. The flow direction is changed from a direction parallel to the cylinder axis 7 as indicated by arrows 90 and 92 to a direction perpendicular to the cylinder axis 7 as indicated by an arrow 91 by a partition wall 561. For this reason, it comes into contact with the ceiling wall 562 or the recess 563 of the cylinder side recess 564 in the third breather passage 56 and is liable to be liquefied, and the liquefied oil is collected in the recess 563. Then, the oil accumulated in the recess 563 is sucked by the oil pump 63 and quickly dispersed in the crank chamber 41. Therefore, it is possible to suppress excessive inflow of oil mist into the valve mechanism chamber 50, and oil adheres to the air cleaner 70 described above to cause intake resistance, and oil consumption increases due to oil burning. In addition, it is possible to more effectively suppress the generation of white smoke, carbon accumulation in the combustion chamber, and deterioration of the exhaust gas characteristic value, and the oil accumulated in the liquefied oil mist is circulated quickly, Oil can be used efficiently.

  In the above-described embodiment, the crank chamber side opening 551 of the second breather passage 55 is located inside the annular recess 612 of the driven gear 61 as shown in FIGS. It is not limited to the configuration. For example, the crank chamber side opening 551 is located inside the root circle 613 (see FIG. 7) of the driven gear 61, located inside the outer peripheral edge 614 (see FIG. 7) of the driven gear 61, or Even if the crank chamber side opening 551 is positioned so that part of the crank chamber side opening 551 overlaps part of the outer peripheral edge 614 of the driven gear 61 as viewed in the direction of the axis 62 of the crankshaft 60, The position can be appropriately selected as long as excessive inflow can be regulated. Further, the area and shape of the crank chamber side opening 551 and the amount of overlap between the crank chamber side opening 551 and the annular recess 612 of the driven gear 61 in the direction of the axis 62 of the crankshaft 60 are limited to those of the above-described embodiment. Instead, it can be determined appropriately according to the amount of oil mist flowing into the valve mechanism chamber 50.

  In the above-described embodiment, the crank chamber side opening 551 of the second breather passage 55 is located inside the annular recess 612 of the driven gear 61 in the axial direction 62 of the camshaft 60 as shown in FIG. However, it is not necessarily limited to this configuration. For example, as shown in FIG. 16, an annular protrusion 1612 is formed on the rotation surface 1611 of the driven gear 161, and the protrusion 1612 is opposed to the protrusion 1612 of the driven gear 61 in the crank chamber side opening 1551. An arcuate recess 1552 that can be partially covered is formed. Further, the right end portion in FIG. 16 of the protrusion 1612 in the direction of the camshaft axis 62 may be configured to be located on the left side of the side surface located on the leftmost side of the recess 1552. Also in this case, the crank chamber side opening 1551 is formed in a labyrinth shape between the recess 1552 and the protruding portion 1612 of the driven gear 61, and it is possible to restrict the flow of oil mist into the crank chamber side opening 1551. Thus, the same effect as described above can be obtained.

  Further, since the recess 563 in which oil is accumulated in the third breather passage 56 is formed on the crankcase side, the influence of heat is less than that of the cylinder block 3 in which the combustion chamber 20 is provided, and oil deterioration can be suppressed. it can. Further, since the third breather passage 56 is formed with the recess 563 and the cylinder side recess 564, even when the engine 1 is tilted during the operation of the brush cutter 1001 or the like, the recess 563 in the third breather passage 56 or Oil can be temporarily stored in the cylinder side recess 564. In particular, even when the oil accumulated in the recess 563 overflows when the engine 1 is greatly inclined, it can be retained in the cylinder-side recess 564. Therefore, when the engine 1 is tilted, the oil is suppressed from flowing into the valve mechanism chamber 50, and the oil adheres to the air cleaner 70 and becomes an intake resistance, or the oil consumption increases due to the oil burning. In addition, generation of white smoke, carbon deposition in the combustion chamber, and deterioration of exhaust gas characteristic values can be more effectively suppressed.

  The offset amount of the first breather passage 54 and the second breather passage 55, the opening area in the third breather passage 56, the depth of the recess 563 or the cylinder side recess 564 of the third breather passage 56, etc. are necessary. It can be appropriately selected depending on the case.

  According to the engine 1 configured as described above, when the engine 1 is started and the flywheel magneto 12 rotates, cooling air is generated by the cooling fan 32 formed in the flywheel magneto 12. As shown by arrows in FIG. 9, the cooling air is guided to the air guide plates 29 and 30 and passes between the cooling fins 31 formed in the cylinder head 2 and the cylinder block 3 along the cylinder head 2 and the cylinder block 3. The cylinder head 2 and the cylinder block 3 are cooled.

  9, when viewed in the direction of the cylinder axis 7, the combustion chamber side intake opening 27 and the combustion chamber side exhaust opening 28 are substantially parallel to the axis 26 of the crankshaft 10, and the combustion chamber side intake opening 27 is a flywheel magnet. The exhaust ports 22 are arranged side by side so as to be located on the 12 side, and the exhaust port 22 is away from the combustion chamber side exhaust opening 28 away from the axis 26 of the crankshaft 10 and toward the muffler 25, and in the direction of the axis 26 of the crankshaft 10. The distance from the combustion chamber side exhaust opening 28 increases so as to increase as the distance from the combustion chamber side exhaust opening 28 increases. Therefore, on the side surface of the cylinder head 2 and the cylinder block 3 on the muffler 25 side, the cooling air flowing between the cooling fins 31 formed in the cylinder head 2 and the cylinder block 3 is viewed from the direction of the cylinder axis 7 in the crankshaft 10. In the direction of the axial line 26, the exhaust port 22 and the discharge-side opening 221 can flow beyond the side of the combustion chamber 20 without being hindered by the flow. Therefore, the vicinity of the high-temperature combustion chamber 20 can be efficiently cooled by the cooling air.

  In particular, as shown in FIG. 9, the discharge side opening 221 is located at the end of the side surface above the cylinder head 2 on the side away from the flywheel magneto 12. For this reason, it becomes possible to lengthen the path in the direction of the axis 26 of the crankshaft 10 of the cooling air flowing on the upper side surfaces of the cylinder head 2 and the cylinder block 3, and the cylinder head 2, the cylinder block 3, and the combustion chamber 20 side. The cooling effect can be further improved around the part.

  As shown in FIG. 9, the intake port 21 is in a direction away from the combustion chamber side intake opening 27 from the axis 26 of the crankshaft 10 when viewed in the direction of the cylinder axis 7, and below the position where the insulator 23 and the carburetor 24 are attached. In the direction toward the side surface of the cylinder head 2, the cylinder head 2 extends to the suction side opening 211 that opens on the lower side surface in FIG. 9 so as to approach the outer peripheral surface of the cylinder head 2 facing the flywheel magneto 12. For this reason, the flow of the cooling air generated by the cooling fan 32 along the side surfaces of the cylinder head 2 and the cylinder block 3 on the carburetor 24 side is obstructed by the intake port 21 and the intake side opening 211. A part of the hindered flow flows along the side surface of the cylinder head 2 and the cylinder block 3 facing the cooling fan 32 and then flows along the side surface of the cylinder head 2 and the cylinder block 3 facing the muffler 25. It will be. Therefore, more cooling air can be guided to the side surface of the cylinder head 2 and the cylinder block 3 facing the muffler 25, and the cylinder head 2 and the cylinder block 3 can be cooled more efficiently.

  As shown in FIG. 9, a spark plug mounting hole 33 for providing a spark plug (not shown) is formed on the right side of the intake port 21 in FIG. For this reason, even when the flow of cooling air around the spark plug is reduced by being blocked by the intake port 21 and the suction side opening 211, the spark plug is cooled by the intake port 21 that is cooled by the low-temperature air-fuel mixture flowing. It is also possible to obtain a further effect that the periphery can be cooled. Further, since the spark plug is located leeward with respect to the intake port 21, the cooling air is blocked by the intake port 21, so that the cooling air does not easily flow through the spark plug, and the cooling air hinders ignition. Can be suppressed.

  Further, the muffler 25 has a substantially flat rectangular parallelepiped shape, and is arranged so that the surface having the maximum area of the muffler 25 faces the upper side surface of the cylinder head 2 as shown in FIG. For this reason, it becomes possible to guide the cooling air along the side surfaces of the cylinder head 2 and the cylinder block 3 together with the air guide plate 29, and the cylinder head 2 and the cylinder block 3 can be efficiently cooled.

  As shown in FIG. 10, an exhaust inflow port 251 is provided near the upper left end of the surface of the muffler 25 facing the cylinder head 2 at a position corresponding to the discharge side opening 221 of the cylinder head 2. A connection passage 255 is provided in the vicinity of the lower right end of the partition wall 255 that divides the interior into the first chamber 253 and the second chamber 254, and an exhaust outlet 256 is provided on the right side surface of the second chamber 254 in FIG. Yes. For this reason, the exhaust flowing into the muffler 25 from the exhaust inlet 251 moves in the muffler 25 in the direction of the axis 26 of the crankshaft 10 from the vicinity of one end of the muffler 25 to the vicinity of the other end. The sound is silenced by moving through a long passage via the first chamber 253, the connection passage 255, and the second chamber 254. Accordingly, it is possible to suppress the size of the muffler 25 in the cylinder axis 7 direction while maintaining the silencing effect, and to greatly improve the design and design freedom of the engine or the engine tool such as a brush cutter equipped with the engine. Is possible.

  In the above-described embodiment, as shown in FIG. 9, the exhaust port 22 extends toward the discharge-side opening 221 located at the end of the side surface above the cylinder head 2 away from the flywheel magneto 12. However, the position of the discharge side opening 221 is not limited to the vicinity of the right end of the side surface above the cylinder head 2 in FIG. 9, and may be located at a position shifted from the right end to the left side. Further, the intake port 21 also extends toward the left side of the side surface below the cylinder head 2 from the intake port 21 shown in FIG. 9 as long as a space for forming the spark plug mounting hole 33 for providing the spark plug can be secured. It may be.

  In the engine 1 to which the above-described first gasket 126 is attached, when the piston 6 descends and the intake valve 18 opens, the air-fuel mixture flows at high speed through the intake passage 241 of the carburetor 24 and the intake passage opening 261 of the first gasket 126. . For this reason, the outer peripheral portions of the intake passage 241 and the intake passage opening 261 become negative pressure, and this pressure is transmitted from the first connection portion 264 of the first gasket 126 to the pulse hole 242 of the carburetor 24 through the pulse pressure communication passage 267. The On the other hand, when the intake valve 18 is closed, the pressure in the intake passage 241 and the intake passage opening 261 becomes atmospheric pressure, and the first connection portion 264 of the first gasket 126 passes through the pulse pressure communication passage 267 to the pulse hole 242 of the carburetor 24. Pressure is transmitted. Therefore, it is possible to transmit the pressure fluctuation due to the opening / closing of the intake valve 18 from the first connection portion 264 of the first gasket 126 to the pulse hole 242 of the carburetor 24 through the pulse pressure communication passage 267 and move the diaphragm of the carburetor 24 to move the fuel. Can be supplied to the carburetor 24.

  Since the carburetor 24 and the first gasket 126 are adjacent to each other, the position of the intake passage 241 of the carburetor 24 and the opening 261 for the intake passage of the first gasket 126 and the pulse hole 242 of the carburetor 24 and the pulse communication hole 262 of the first gasket 126 are included. When the carburetor 24 and the first gasket 126 are attached at the two positions, the diaphragm of the carburetor 24 can be easily driven. Since the carburetor 24 is attached to the insulator 23 together with the first gasket with a common mounting screw, the above-mentioned two positions can be easily realized, and the assembly work of the engine 1 can be easily performed. Manufacturing cost can be reduced. Further, since the first gasket 126 is thicker than the other gaskets, it is also possible to prevent the first connecting portion 264, the pulse pressure communication passage 267, and the pulse communication hole 262 from being crushed during the mounting operation of the carburetor 24 and preventing the transmission of pressure fluctuations. From this point, the assembly work can be easily performed, and the pressure fluctuation can be reliably transmitted and the manufacturing cost can be further reduced.

  Further, the first connecting portion 264 of the pulse pressure communication passage 267 of the first gasket 126 has a direction from the bottom dead center to the top dead center in the cylinder axial direction when the carburetor 24 is attached to the engine 1. 14 is connected to the upper end of the intake passage opening 261 as shown in FIG. The pulse pressure communication passage 267 is connected to the pulse connection hole through an extension part 265 extending upward from the first connection part 264 and a direction changing part 266 connected to the extension part 265 and extending downward on the right side. 262 is reached. For this reason, even when part of the fuel in the air-fuel mixture liquefies in the intake passage 241, it becomes difficult to enter the first connection portion 264, and transmission of pressure fluctuations to the diaphragm of the carburetor 24 is hindered. Therefore, the pressure fluctuation can be transmitted reliably. Further, even if the liquefied fuel enters the pulse pressure communication passage 267 when the engine 1 is tilted, the liquid is discharged from either end by the extending portion 265 or the direction changing portion 266. It can be suppressed that the liquid stays inside the passage 267 and obstructs the transmission of pressure fluctuation.

  In the above-described embodiment, the intake passage opening 261, the mounting hole 263, the pulse communication hole 262, and the pulse pressure communication passage 267 of the first gasket 126 are all formed so as to penetrate in the thickness direction of the first gasket 126. However, it is not limited to this configuration. For example, as shown in FIG. 17, a first connecting portion (not shown), a pulse communication hole (not shown), and a pulse pressure communication passage 1267 are formed in a concave groove shape on the surface of the first gasket 1026 facing the carburetor 24. In this case, the same effect as described above can be obtained.

  Further, in the above-described embodiment, the positions of the pulse hole 242 of the carburetor 24 and the pulse communication hole 262 of the first gasket 126 are set so that the top dead center is changed from the bottom dead center in the cylinder axis direction when the carburetor 24 is attached to the engine 1. However, the present invention is not necessarily limited to this configuration, although it is positioned below the intake passage 241 and the intake passage opening 261. For example, the pulse hole 242 and the pulse communication hole 262 may be configured to be positioned below the first connection portion 264. Even in this case, it is suppressed that the pulse pressure communication passage 267 is blocked by the liquefied fuel in the intake passage 241 by the extending portion 265 and the direction changing portion 266 and the transmission of pressure fluctuation is inhibited. can do.

  In the above-described embodiment, the engine 1 is mounted on the brush cutter 1001, but the engine 1 is not limited to mounting on the brush cutter 1001, and is mounted on an engine tool such as a chain saw, a blower, or a hedge trimmer. It may be.

DESCRIPTION OF SYMBOLS 1 Engine 3 Cylinder block 4 Crankcase 6 Piston 10 Crankshaft 11 Starter mechanism 12 Flywheel magneto 21 Intake port 22 Exhaust port 23 Insulator 24 Carburetor 25 Muffler 27 Combustion chamber side intake opening 28 Combustion chamber side exhaust opening 31 Cooling fin 32 Cooling fan 33 Spark plug mounting hole 41 Crank chamber 42 Oil chamber 44 Vertical partition wall 43 Horizontal partition wall 45 Communication passage 50 Valve mechanism chamber 60 Camshaft 70 Air cleaner 126 First gasket 241 Intake passage 242 Pulse hole 261 Intake passage opening 262 Pulse communication hole 264 First connection portion 267 Pulse pressure communication passage

Claims (13)

A gasket disposed between a diaphragm carburetor having an intake passage and a diaphragm drive pulse hole, and an insulator connected to an intake port of the engine,
The gasket, possess an intake passage opening provided at a position corresponding to the intake passage of the carburetor, and a pulse pressure communication passage communicating with said pulse hole and the intake passage opening,
The pulse pressure communication path is
A first connection portion connected to the intake passage opening at one end;
A second connection portion provided at a position corresponding to the pulse hole at the other end;
The first connecting portion is connected to an outer peripheral edge of the intake passage opening;
The pulse pressure communication passage includes an extension portion extending from the first connection portion toward an outside direction of the intake passage opening, and a direction changing portion connected to the extension portion to bend the pulse pressure communication passage. Comprising
Diaphragm type carburetor gasket characterized by that. The intake passage opening to have a substantially circular flow cross-section,
The diaphragm type carburetor gasket according to claim 1 . The second connection portion is arranged in a radial direction of the intake passage opening passing through the center of the first connection portion and the intake passage opening from the first connection portion to the first connection portion. Located on the side toward the center,
The diaphragm type carburetor gasket according to claim 2 . The second connection portion is positioned beyond the intake passage opening in a radial direction of the intake passage opening passing through the first connection portion and the center of the intake passage opening;
The diaphragm type carburetor gasket according to claim 3 . The pulse pressure communication passage is a through groove that penetrates from a surface facing the carburetor to a surface facing the insulator.
The gasket for diaphragm type carburetors according to any one of claims 1 to 4 . The pulse pressure communication passage is formed in a concave groove shape on a surface facing the carburetor.
The gasket for diaphragm type carburetors according to any one of claims 1 to 4 . The insulator is connected to the intake port via an insulator gasket;
The thickness of the diaphragm carburetor gasket is greater than the thickness of the insulator gasket,
The diaphragm type carburetor gasket according to any one of claims 1 to 6 . The diaphragm-type carburetor gasket according to any one of claims 1 to 7 is provided between the carburetor and the insulator.
A four-cycle engine characterized by that. A four-cycle engine comprising the diaphragm carburetor gasket according to any one of claims 2 to 7 between the carburetor and the insulator,
In the cylinder axis direction of the 4-cycle engine,
The first connection portion is located on the direction side from the bottom dead center to the top dead center of the 4-cycle engine from the center of the intake passage opening.
The four-cycle engine according to claim 8 . A tank for storing fuel,
An intake passage provided in the carburetor, through which an air-fuel mixture containing the fuel flows;
A fuel supply section for supplying the fuel into the intake passage,
The first connection portion is located on the opposite side of the fuel supply portion with respect to the center of the intake passage.
The four-cycle engine according to claim 9 . The second connection portion is located on the side of the first connection portion from the top dead center toward the bottom dead center.
The four-cycle engine according to claim 9 or 10 , characterized in that The first connection portion before SL, the distance from the center of the front Symbol intake passage opening is connected to the outer periphery of the intake passage opening with a maximum in a direction toward the top dead center from the bottom dead center,
The four-cycle engine according to any one of claims 9 to 11 , wherein the four-cycle engine is provided. The four-cycle engine according to any one of claims 8 to 12 , comprising:
An engine tool characterized by that.

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