EP1134366A1 - Tragbarer Viertaktmotor - Google Patents

Tragbarer Viertaktmotor Download PDF

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Publication number
EP1134366A1
EP1134366A1 EP01106280A EP01106280A EP1134366A1 EP 1134366 A1 EP1134366 A1 EP 1134366A1 EP 01106280 A EP01106280 A EP 01106280A EP 01106280 A EP01106280 A EP 01106280A EP 1134366 A1 EP1134366 A1 EP 1134366A1
Authority
EP
European Patent Office
Prior art keywords
oil
oil tank
valve
crankshaft
cylinder block
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP01106280A
Other languages
English (en)
French (fr)
Other versions
EP1134366B1 (de
Inventor
Keita c/o K.K. Honda Gijutsu Kenkyusho Ito
Takao /o K.K. Honda Gijutsu Kenkyusho Nishida
Sei /o K.K. Honda Gijutsu Kenkyusho Watanabe
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Honda Motor Co Ltd
Original Assignee
Honda Motor Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from JP2000076406A external-priority patent/JP3908887B2/ja
Priority claimed from JP2000076408A external-priority patent/JP3845243B2/ja
Priority claimed from JP2000076407A external-priority patent/JP3975046B2/ja
Priority claimed from JP2000079308A external-priority patent/JP3803526B2/ja
Priority claimed from JP2000079307A external-priority patent/JP3819666B2/ja
Application filed by Honda Motor Co Ltd filed Critical Honda Motor Co Ltd
Publication of EP1134366A1 publication Critical patent/EP1134366A1/de
Application granted granted Critical
Publication of EP1134366B1 publication Critical patent/EP1134366B1/de
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B75/00—Other engines
    • F02B75/16—Engines characterised by number of cylinders, e.g. single-cylinder engines
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01M—LUBRICATING OF MACHINES OR ENGINES IN GENERAL; LUBRICATING INTERNAL COMBUSTION ENGINES; CRANKCASE VENTILATING
    • F01M1/00—Pressure lubrication
    • F01M1/04—Pressure lubrication using pressure in working cylinder or crankcase to operate lubricant feeding devices
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01M—LUBRICATING OF MACHINES OR ENGINES IN GENERAL; LUBRICATING INTERNAL COMBUSTION ENGINES; CRANKCASE VENTILATING
    • F01M11/00—Component parts, details or accessories, not provided for in, or of interest apart from, groups F01M1/00 - F01M9/00
    • F01M11/06—Means for keeping lubricant level constant or for accommodating movement or position of machines or engines
    • F01M11/062—Accommodating movement or position of machines or engines, e.g. dry sumps
    • F01M11/065—Position
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01M—LUBRICATING OF MACHINES OR ENGINES IN GENERAL; LUBRICATING INTERNAL COMBUSTION ENGINES; CRANKCASE VENTILATING
    • F01M9/00—Lubrication means having pertinent characteristics not provided for in, or of interest apart from, groups F01M1/00 - F01M7/00
    • F01M9/06—Dip or splash lubrication
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B63/00—Adaptations of engines for driving pumps, hand-held tools or electric generators; Portable combinations of engines with engine-driven devices
    • F02B63/02—Adaptations of engines for driving pumps, hand-held tools or electric generators; Portable combinations of engines with engine-driven devices for hand-held tools
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B67/00—Engines characterised by the arrangement of auxiliary apparatus not being otherwise provided for, e.g. the apparatus having different functions; Driving auxiliary apparatus from engines, not otherwise provided for
    • F02B67/04—Engines characterised by the arrangement of auxiliary apparatus not being otherwise provided for, e.g. the apparatus having different functions; Driving auxiliary apparatus from engines, not otherwise provided for of mechanically-driven auxiliary apparatus
    • F02B67/06—Engines characterised by the arrangement of auxiliary apparatus not being otherwise provided for, e.g. the apparatus having different functions; Driving auxiliary apparatus from engines, not otherwise provided for of mechanically-driven auxiliary apparatus driven by means of chains, belts, or like endless members
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02F—CYLINDERS, PISTONS OR CASINGS, FOR COMBUSTION ENGINES; ARRANGEMENTS OF SEALINGS IN COMBUSTION ENGINES
    • F02F1/00—Cylinders; Cylinder heads 
    • F02F1/02—Cylinders; Cylinder heads  having cooling means
    • F02F1/04—Cylinders; Cylinder heads  having cooling means for air cooling
    • F02F1/06—Shape or arrangement of cooling fins; Finned cylinders
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02F—CYLINDERS, PISTONS OR CASINGS, FOR COMBUSTION ENGINES; ARRANGEMENTS OF SEALINGS IN COMBUSTION ENGINES
    • F02F1/00—Cylinders; Cylinder heads 
    • F02F1/24—Cylinder heads
    • F02F1/26—Cylinder heads having cooling means
    • F02F1/28—Cylinder heads having cooling means for air cooling
    • F02F1/30—Finned cylinder heads
    • F02F1/305—Finned cylinder heads the cylinder heads being of side valve type
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B75/00—Other engines
    • F02B75/02—Engines characterised by their cycles, e.g. six-stroke
    • F02B2075/022—Engines characterised by their cycles, e.g. six-stroke having less than six strokes per cycle
    • F02B2075/027—Engines characterised by their cycles, e.g. six-stroke having less than six strokes per cycle four
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B2275/00—Other engines, components or details, not provided for in other groups of this subclass
    • F02B2275/22—Side valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B2275/00—Other engines, components or details, not provided for in other groups of this subclass
    • F02B2275/30—Inverted positioning of engines
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
    • F02B2275/00—Other engines, components or details, not provided for in other groups of this subclass
    • F02B2275/34—Lateral camshaft position

Definitions

  • the present invention relates to improvement of handheld type four-cycle engines which can desirably be used mainly as a power source for machines for portable operation such as trimmers.
  • the lubrication system disclosed in the above-mentioned patent publication has a comparatively long and complicated circulation route in which the oil mist is circulated from the oil tank to the crank chamber, then to the valve operation chamber and is then returned to the oil tank.
  • Such a long and complicated circulation route for the oil mist causes an increase in the size of the engine main body, which includes the circulation route, and makes it difficult to reduce the weight thereof.
  • Weight reduction is one of the important issues when considering improvements in the operability of, in particular, handheld type four-cycle engines.
  • the present invention has been carried out in view of the above-mentioned circumstances, and it is an object of the present invention to provide a handheld type four-cycle engine which can reliably lubricate the valve operation mechanism regardless of the operational position of the engine while making the engine main body more compact and lighter.
  • a handheld type four-cycle engine including a crankcase having a crank chamber housing a crankshaft; a cylinder block having a cylinder bore; and an intake valve, an exhaust valve and a valve operation mechanism provided in a side wall of the cylinder block, the valve operation mechanism being operable in association with the crankshaft so as to open and close the intake valve and the exhaust valve, wherein an oil tank for storing oil is provided in one side wall running the length of the crankcase and the cylinder block, and the oil tank houses the valve operation mechanism and oil mist generation means for generating oil mist from the stored oil.
  • each part of the valve operation mechanism disposed inside the oil tank can be lubricated reliably by the above-mentioned oil mist regardless of the operational position of the engine. It is therefore unnecessary to provide the engine main body with a special oil supply passage for lubricating the valve operation mechanism, and the size and weight of the engine can thus be reduced.
  • the oil tank is provided in one side wall running the length of the crankcase and the cylinder block, it is unnecessary to provide an oil reservoir in the lower part of the crankcase, and the total height of the engine can thus be reduced and the size of the engine can be further reduced.
  • a handheld type four-cycle engine wherein an outward route and an return route are provided for communication between the oil tank and the crank chamber above the oil stored in the oil tank, and valve means is provided for introducing the positive pressure component of pressure pulsations generated in the crank chamber into the side of the oil tank.
  • valve means corresponds to the one-way valve 51 described in the embodiment of the present invention below.
  • the crankshaft and the piston can be lubricated regardless of the operational position of the engine. Moreover, since it is sufficient for the oil mist to merely circulate between the two chambers, that is to say, the oil tank and the crank chamber, the outward and return routes for providing communication between the two chambers can be made comparatively short and simple, and the size and weight of the engine can be further reduced.
  • a handheld type four-cycle engine wherein a breather chamber is communicated with the return route between the valve means and the oil tank, and the breather chamber is communicated with an air cleaner of an intake system on one side and with a suction chamber communicated with the oil tank via an orifice on the other side.
  • the blowby gas generated in the crank chamber is transferred to the breather chamber together with the oil mist, and separated into gas and liquid. Then, the blowby gas is discharged to the air cleaner, and the liquefied oil flows into the suction chamber via the orifice and can be returned to the low pressure oil tank.
  • a handheld type four-cycle engine including a crankcase having a crank chamber housing a crankshaft; a cylinder block having a cylinder bore; and an intake valve, an exhaust valve and a valve operation mechanism provided in a side wall of the cylinder block, the valve operation mechanism being operable in association with the crankshaft so as to open and close the intake valve and the exhaust valve, characterised in that an oil tank for storing oil that is separate from the crank chamber is provided in one side wall running the length of the crankcase and the cylinder block, the oil tank houses the valve operation mechanism and oil mist generation means for generating oil mist from the stored oil and is arranged so that the oil mist generated inside the oil tank can be supplied to the crank chamber, a cooling fan driven by the crankshaft is placed so as to adjoin the oil tank, and a power output mechanism is provided on the crankshaft so that the crankcase is interposed between the power output mechanism and the oil tank.
  • the oil tank is provided in one side wall running the length of the crankcase and the cylinder block, it is unnecessary to provide an oil reservoir in the lower part of the crankcase, the total height of the engine can thus be reduced and the engine can be made compact. Moreover, since the oil tank is filled with the oil mist generated by the oil mist generation means and the oil mist is supplied to the crank chamber, each component inside the crank chamber as well as the valve operation mechanism placed inside the oil tank can be lubricated reliably regardless of the operational position of the engine.
  • the cooling fan is placed so as to adjoin the oil tank, the oil tank and, therefore, the stored oil and the oil mist inside the oil tank can be cooled effectively by the cooling air generated by the cooling fan, thus efficiently carrying out lubrication and cooling of each component.
  • valve operation mechanism and the power output mechanism are linked to the two ends of the crankshaft, the loads arising from the valve operation mechanism and the power output mechanism, during operation of the engine, are applied to the two separate ends of the crankshaft, it is thus possible to prevent the load applied to the crankshaft, its bearings and the side wall of the crankcase from being localised and the durability thereof can be enhanced.
  • a handheld type four-cycle engine wherein a carburettor and an exhaust muffler are placed on the two sides of the cylinder block along a direction perpendicular to the,axes of both the cylinder bore and the crankshaft.
  • the carburettor and the exhaust muffler can be easily arranged without any obstruction from the oil tank, the cooling fan or the power output mechanism thus helping to make the engine more compact.
  • the above-mentioned oil mist generation means corresponds to the oil slingers 36 to 41 described in the embodiment of the present invention below, and the above-mentioned power output mechanism corresponds to the centrifugal clutch 31 described in the embodiment below.
  • Fig. 1 is an oblique view showing one embodiment of the handheld type four-cycle engine of the present invention in practical use.
  • Fig. 2 is a vertically sectioned view of the above-mentioned four-cycle engine.
  • Fig. 3 is a cross-sectional view at line 3-3 in Fig. 2.
  • Fig. 4 is a cross-sectional view at line 4-4 in Fig. 3.
  • Fig. 5 is a cross-sectional view at line 5-5 in Fig. 4.
  • Fig. 6 is a cross-sectional view at line 6-6 in Fig. 5.
  • a handheld type four-cycle engine E to which the present invention is applied is fitted as the source of power to the driving section of, for example, a powered trimmer T. Since the powered trimmer T is used in a manner in which a cutter C is positioned in various directions according to the operational conditions, the engine E is also tilted to a large extent or turned upside-down as a result, and the operational position is unstable.
  • the engine main body 1 of the above-mentioned handheld type four-cycle engine E includes a crankcase 6 having a crank chamber 6a, a cylinder block 7 having one cylinder bore 7a, and a cylinder head 8 having a combustion chamber 8a, and a large number of cooling fins 11 are formed on the outer peripheries of the cylinder block 7 and the cylinder head 8.
  • crankshaft 12 housed in the crank chamber 6a is supported in right and left side walls of the crankcase 6 in a rotatable manner via ball bearings 14 and 14' and is also connected to a piston 15 fitted in the cylinder bore 7a via a connecting rod 16.
  • An oil tank 13 is provided as a continuation of the left side wall running the length of the crankcase 6 and the cylinder block 7.
  • the oil tank 13 includes a tank inner half 13a and a tank outer half 13b, the tank inner half 13a being linked integrally to the crankcase 6 and the cylinder block 7, and the tank outer half 13b being bolt-joined to the tank inner half 13a.
  • the left-hand end of the crankshaft 12 runs through and projects out of the oil tank 13, and an oil seal 17 in close contact with the outer circumference of the crankshaft 12 is fitted in the tank outer half 13b.
  • a flywheel 24 having a large number of cooling vanes 25 is fixed to the left-hand end of the crankshaft 12 projecting out of the oil tank 13, the flywheel 24 functioning also as a cooling fan, and a recoil type starter 26 is placed outside the flywheel 24.
  • An oil seal 17' is fitted in the right side wall of the crankcase 6 so as to adjoin the outside of the bearing 14', the right-hand end of the crankshaft 12 runs through and projects out of the oil seal 17', a drive plate 27 is fixed to the right hand end of the crankshaft 12, and a plurality of centrifugal shoes 28 (one thereof is shown in the figure) are pivotally supported on the drive plate 27 in a rockable manner. These centrifugal shoes 28, together with a clutch drum 30 connected to the drive shaft 29 for driving the aforementioned cutter C, form a centrifugal clutch 31.
  • the cylinder block 7 and the cylinder head 8 share an overhang section 19 which overhangs on the side of the oil tank 13, and the lower part of the overhang section 19 forms a part of the upper wall of the tank inner half 13a.
  • the combustion chamber 8a is formed in the part of the cylinder head 8 corresponding to this overhang section 19, and an intake port 9i and an exhaust port 9e communicated with the combustion chamber 8a are formed in the cylinder block 7.
  • An ignition plug 10 is screwed into the cylinder head 8, the electrodes of the ignition plug 10 projecting into the combustion chamber 8a.
  • the valve operation mechanism 23 includes a drive gear 32 fixed to the crankshaft 12, a pair of driven gears 36 and 37 supported in a rotatable manner on a pair of support shafts 33 and 34 provided in the oil tank 13 above the crankshaft 12 and driven by the drive gear 32 with a reduction ratio of 1/2, an intake cam 21 i and an exhaust cam 21e formed integrally with the driven gears 36 and 37 respectively, an intake cam follower 22i pivotally supported in the oil tank 13 in a rockable manner and provided between the intake cam 21 i and the intake valve 18i, an exhaust cam follower 22e pivotally supported in the oil tank 13 in a rockable manner and provided between the exhaust cam 21e and the exhaust valve 18e, and valve springs 20i and 20e forcing the intake valve 18i and the exhaust valve 18e towards the closing direction.
  • the engine E is thus arranged to be of the side valve type.
  • the driven gear 36 and the intake cam 21 i, and also the driven gear 37 and the exhaust cam 21e are placed distant from each other in the axial direction so that they closely adjoin the left and right side walls respectively of the oil tank 13.
  • Gear type oil slingers 39 and 40 are formed integrally with the intake cam 21 i and the exhaust cam 21e respectively so as to adjoin them.
  • Another support shaft 35 is provided in the oil tank 13 at a position beneath the crankshaft 12, and this support shaft 35 supports a driven gear 38 and a vane type oil slinger 41 in a rotatable manner, the driven gear 38 being driven by the drive gear 32 and the oil slinger 41 being integral with the driven gear 38.
  • the driven gear 38 and the oil slinger 41 are positioned distant from each other in the axial direction so that they closely adjoin the left and right inner walls respectively of the oil tank 13.
  • a predetermined amount of lubricating oil O is stored in the oil tank 13, at least one of the three driven gears 36 to 38 or the three oil slingers 39 to 41 is partially immersed in the stored oil O regardless of the operational position of the engine E, and the stored oil O is scattered by the rotation thereof so generating an oil mist.
  • the three driven gears 36 to 38 therefore also function as oil slingers, and in fact, the three support shafts 33, 34 and 35 support a pair of oil slingers 36 and 39; 37 and 40; and 38 and 41 respectively, the oil slingers of each pair being distant from each other in the axial direction.
  • the intake port 9i is connected to a carburettor 2 and an air cleaner 4 in that order, and the exhaust port 9e is connected to an exhaust muffler 3.
  • the carburettor 2 and the exhaust muffler 3 are placed along a direction perpendicular to the axes of both the crankshaft 12 and the cylinder bore 7a.
  • An outward route 45 and an return route 46 for circulating the oil mist generated inside the oil tank 13 between the oil tank 13 and the crank chamber 6a are provided between the above-mentioned two chambers 13 and 6a.
  • the outward route 45 includes a through hole formed in the crankshaft 12 and providing communication between the oil tank 13 and the crank chamber 6a.
  • the return route 46 includes a valve hole 47 in the bottom wall of the crankcase 6, a valve chamber 48 communicated with the crank camber 6a via the valve hole 47, and a first return pipe 49 providing communication between the valve chamber 48 and the oil tank 13.
  • a one-way valve 51 is provided in the valve chamber 48, the one-way valve 51 including a reed valve for blocking and unblocking the valve hole 47.
  • the open ends of the above-mentioned outward route 45 and the first return pipe 49 inside the oil tank 13 are arranged so that they are always above the liquid level of the stored oil O regardless of the operational position of the engine E.
  • a breather chamber 53 is provided on one side of the valve chamber 48, the breather chamber 53 being communicated with the valve chamber 48 via a link hole 52.
  • the breather chamber 53 is partitioned into a plurality of expansion chambers 53a, 53b (two chambers in the figure) by means of a wall 54. These expansion chambers 53a and 53b are communicated with each other via throttle passages 55 and 55 on both sides of the wall 54, and the expansion chamber 53b furthest from the link hole 52 is communicated with the above-mentioned air cleaner 4 via a breather pipe 56.
  • a horizontally flattened chamber 57a is provided immediately below the breather chamber 53, a vertically flattened chamber 57b is provided in the side wall of the breather chamber 53 on the side of the oil tank 13, the vertically flattened chamber 57b rising at one end of the horizontally flattened chamber 57a, and a suction chamber 57 is formed by the two flattened chambers 57a and 57b.
  • the horizontally flattened chamber 57a is communicated with the breather chamber 53 via orifices 58, 58 ⁇ separately placed at several positions, and the vertically flattened chamber 57b is also communicated with the breather chamber 53 via orifices 58, 58 ⁇ provided close to the ceiling of the breather chamber 53.
  • the suction chamber 57 is communicated with the inside of the oil tank 13 via a second return pipe 59.
  • the second return pipe 59 is arranged so that the open end thereof inside the oil tank 13 is always above the liquid level of the stored oil O regardless of the operational position of the engine E.
  • the valve operation mechanism 23 is provided inside such an oil tank 13, the intake cam 21 i and the exhaust cam 21e rotating together with the upper driven gears 36 and 37 operate the intake valve 18i and the exhaust valve 18e so as to open and close them with appropriate timing via the cam followers 22i and 22e while working co-operatively with the valve springs 20i and 20e, and each component of the valve operation mechanism 23 can therefore be lubricated effectively by the above-mentioned oil mist. It is therefore unnecessary to provide the engine main body 1 with a special oil supply passage for lubricating the valve operation mechanism 23, and the size and weight of the engine E can thus be reduced.
  • the oil tank 13 is provided in one side wall running the length of the crankcase 6 and the cylinder block 7, it is unnecessary to provide an oil reservoir in the lower part of the crankcase 6, the total height of the engine E can be reduced and the size of the engine can further be reduced.
  • a negative pressure and a positive pressure are generated alternately in the crank chamber 6a accompanying the ascending and descending movement of the piston 15 so causing pressure pulsations; when a negative pressure is generated, the one-way valve 51 closes so as to block the valve hole 47 and at the same time the oil mist inside the oil tank 13 is drawn up into the crank chamber 6a through the through hole of the crankshaft 12, that is to say, the outward route 45 thus lubricating the crankshaft 12 and the piston 15. At this stage, the pressure of the oil tank 13 becomes negative due to the oil mist drawn up into the crank chamber 6a.
  • the one-way valve 51 opens so as to unblock the valve hole 47, and the oil mist inside the crank chamber 6a is returned to the oil tank 13 having a low pressure through the return route 46, that is to say, the valve hole 47, the valve chamber 48 and the first return pipe 49. It is thus sufficient for the oil mist to circulate merely between the two chambers, namely the oil tank 13 and the crank chamber 6a, the outward route 45 and the return route 46 providing communication between the above-mentioned two chambers 13 and 6a can be made comparatively short and simple, and the size and weight of the engine main body 1 can be reduced.
  • blowby gas generated in the crank chamber 6a is transferred to the valve chamber 48 together with the oil mist and further to the breather chamber 53 through the link hole 52, and separated into gas and liquid while passing through the first and second expansion chambers 53a and 53b, and the blowby gas alone is discharged to the air cleaner 4 via the breather pipe 56.
  • the oil separated and liquefied in the breather chamber 53 flows into the suction chamber 57 via the orifice 58, 58 ⁇ . Since the first suction chamber 57a and the second suction chamber 57b are communicated with the inside of the oil tank 13 having a low pressure via the second return pipe 59, the oil transferred to the suction chamber 57 is drawn up into the oil tank 13 through the second return pipe 59.
  • the suction chamber 57 includes, in particular, the horizontally flattened chamber 57a and the vertically flattened chamber 57b rising at one end of the horizontally flattened chamber 57a as mentioned above, and each of the two chambers 57a and 57b is communicated with the breather chamber 53 via the orifices 58, 58 ⁇ , the oil stored in the breather chamber 53 can flow into the suction chamber 57 and return to the oil tank 13 even in the case where the engine E is tilted horizontally so positioning the vertically flattened chamber 57b downwards, as well of course in the case where the engine E is upright so positioning the horizontally flattened chamber 57a downwards.
  • the flywheel 24 having the cooling vanes 25 driven by the crankshaft 12 is placed outside the oil tank 13 so as to adjoin it, cooling air drawn in through the air inlet 66 of the engine cover 65 by rotation of the cooling vanes 25 is directly applied to the oil tank 13, the oil mist and the oil O stored inside the oil tank can be cooled effectively and the lubrication and cooling of each part can be carried out efficiently.
  • valve operation mechanism 23 and the centrifugal clutch 31 are linked to the two ends of the crankshaft 12 with the engine main body 1 disposed therebetween, the loads arising from the valve operation mechanism 23 and the drive shaft 29 during operation of the engine E separately work on the two ends of the crankshaft 12. It is therefore possible to prevent the load from being localised on the crankshaft 12, its bearings 14 and 14' and the side wall of the crankcase 6, and the durability thereof can thus be enhanced. Furthermore, since it is unnecessary to specially increase the load capacity of these parts, the engine E can be made more compact.
  • the carburettor 2 and the exhaust muffler 3 are placed along a direction perpendicular to the axes of both the crankshaft 12 and the cylinder bore 7a, the carburettor 2 and the exhaust muffler 3 can easily be arranged without any obstruction from the oil tank 13, the flywheel 24 or the centrifugal clutch 31 which are arranged along the axis of the crankshaft 12 thus helping to make the engine E more compact.
  • a rotary valve operable in association with the crankshaft 12 and operating so as to unblock the outward pipe 45 when the piston 15 descends, and to block the outward pipe 45 when the piston 15 ascends can be provided instead of the one-way valve 51.
  • a handheld type four-cycle engine including, in a side wall of a cylinder block, an intake valve, an exhaust valve and a valve operation mechanism operable in association with a crankshaft so as to open and close the above-mentioned valves and, an oil tank is formed in one side wall of the cylinder block, and the oil tank houses the valve operation mechanism and oil mist generation means for generating an oil mist from stored oil. It is thus possible to reliably lubricate the valve operation mechanism regardless of the operational position of the engine while allowing the size and weight of the engine main body to be reduced.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Lubrication Of Internal Combustion Engines (AREA)
  • Lubrication Details And Ventilation Of Internal Combustion Engines (AREA)
EP20010106280 2000-03-14 2001-03-14 Tragbarer Viertaktmotor Expired - Lifetime EP1134366B1 (de)

Applications Claiming Priority (10)

Application Number Priority Date Filing Date Title
JP2000076408 2000-03-14
JP2000076406A JP3908887B2 (ja) 2000-03-14 2000-03-14 ハンドヘルド型四サイクルエンジン
JP2000076408A JP3845243B2 (ja) 2000-03-14 2000-03-14 ハンドヘルド型四サイクルエンジン
JP2000076407 2000-03-14
JP2000076406 2000-03-14
JP2000076407A JP3975046B2 (ja) 2000-03-14 2000-03-14 ハンドヘルド型四サイクルエンジン
JP2000079308A JP3803526B2 (ja) 2000-03-16 2000-03-16 側弁型エンジン
JP2000079308 2000-03-16
JP2000079307A JP3819666B2 (ja) 2000-03-16 2000-03-16 ハンドヘルド型四サイクルエンジン
JP2000079307 2000-03-16

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EP1134366A1 true EP1134366A1 (de) 2001-09-19
EP1134366B1 EP1134366B1 (de) 2004-04-14

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2003064825A1 (en) * 2002-01-30 2003-08-07 Aktiebolaget Electrolux Crankcase scavenged internal combustion engine

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US4813408A (en) * 1986-04-01 1989-03-21 Mitsubishi Jidosha Kogyo Kabushiki Kaisha Engine cooling device
EP0779412A2 (de) * 1995-12-15 1997-06-18 Honda Giken Kogyo Kabushiki Kaisha Schmieranlage für eine Viertaktbrennkraftmaschinen
EP0887520A1 (de) * 1997-06-26 1998-12-30 Ishikawajima-Shibaura Machinery Co., Ltd. Schmierölversorgungsanlage für Viertaktbrennkraftmaschine
WO1999002824A1 (en) * 1997-07-07 1999-01-21 Ryobi North America, Inc. Multi-position operable four-cycle engine
US5947068A (en) * 1997-10-03 1999-09-07 Kioritz Corporation Four-stroke cycle internal combustion engine
EP0962630A2 (de) * 1998-06-03 1999-12-08 Fuji Robin Kabushiki Kaisha Schmiervorrichtung für eine Viertaktbrennkraftmaschine

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Publication number Priority date Publication date Assignee Title
US4813408A (en) * 1986-04-01 1989-03-21 Mitsubishi Jidosha Kogyo Kabushiki Kaisha Engine cooling device
EP0779412A2 (de) * 1995-12-15 1997-06-18 Honda Giken Kogyo Kabushiki Kaisha Schmieranlage für eine Viertaktbrennkraftmaschinen
EP0887520A1 (de) * 1997-06-26 1998-12-30 Ishikawajima-Shibaura Machinery Co., Ltd. Schmierölversorgungsanlage für Viertaktbrennkraftmaschine
WO1999002824A1 (en) * 1997-07-07 1999-01-21 Ryobi North America, Inc. Multi-position operable four-cycle engine
US5947068A (en) * 1997-10-03 1999-09-07 Kioritz Corporation Four-stroke cycle internal combustion engine
EP0962630A2 (de) * 1998-06-03 1999-12-08 Fuji Robin Kabushiki Kaisha Schmiervorrichtung für eine Viertaktbrennkraftmaschine

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2003064825A1 (en) * 2002-01-30 2003-08-07 Aktiebolaget Electrolux Crankcase scavenged internal combustion engine
US7080620B2 (en) 2002-01-30 2006-07-25 Aktiebolaget Electrolux Crankcase scavenged internal combustion engine
CN1318739C (zh) * 2002-01-30 2007-05-30 电气联合股份有限公司 曲轴箱扫气式内燃机

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EP1134366B1 (de) 2004-04-14

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