JP5741229B2 - Oil lubrication structure of dry sump type engine - Google Patents

Description

  The present invention relates to an oil lubrication structure of a dry sump engine applied to, for example, a motorcycle.

  As a motorcycle engine, a reed valve is arranged between a crank chamber in which a crankshaft is stored and a magneto chamber in which a stator coil and a magnet rotor are stored, and oil flowing into the magneto chamber through the reed valve is oiled. What pumps up with a pump and supplies to an oil storage part is known (for example, refer to patent documents 1). Such a so-called dry sump type engine does not have an oil pan as an oil reservoir at the bottom of the engine, and thus has an advantage that the vertical dimension of the engine can be reduced.

JP 2011-47366 A

  By the way, in the dry sump type engine, when the pressure in the crank chamber is increased by the lowering operation of the piston, the reed valve is opened and the engine oil in the crank chamber is discharged to the magneto chamber and is accumulated at the bottom of the magneto chamber. In this mechanism, when the air compressed by the piston and the engine oil are pushed out into the magneto chamber vigorously, the liquid level of the engine oil that accumulates at the bottom of the magneto chamber may be violently waved. If the liquid level of the engine oil undulates in this way, it will hinder pumping of the engine oil by the oil pump, and problems will arise from the viewpoint of engine oil lubrication and the like.

  The present invention has been made in view of this point, and an object thereof is to provide an oil lubrication structure for a dry sump type engine that suppresses the ripples of engine oil accumulated at the bottom of the magneto chamber.

  The oil lubrication structure of the dry sump type engine of the present invention is a dry sump type engine in which engine oil accumulated at the bottom of the crank chamber is discharged to the magneto chamber through the one-way valve, and is downstream of the one-way valve and An oil passage for guiding engine oil discharged through the one-way valve to the magneto chamber, upstream of the magneto chamber, communicating with the oil passage, and flowing into the magneto chamber from the oil passage And an attenuation chamber configured to be able to suppress the flow rate of air.

  According to this configuration, by providing the damping chamber upstream of the magneto chamber, the compressed air discharged from the one-way valve can be released out of the oil passage, so that the engine oil pushed out from the oil passage to the magneto chamber and The flow rate of air can be suppressed. Thereby, the ripple of the engine oil which accumulates at the bottom of the magneto chamber can be suppressed.

  In the oil lubrication structure of the dry sump type engine of the present invention, the damping chamber may be communicated with a transmission chamber provided in the dry sump type engine. According to this configuration, since the transmission chamber has the same function as the attenuation chamber, it is possible to further suppress the flow rates of the engine oil and air pushed out from the oil passage to the magneto chamber. As a result, it is possible to further suppress the ripple of engine oil that accumulates at the bottom of the magneto chamber.

  In the oil lubrication structure of the dry sump type engine of the present invention, the damping chamber and the transmission chamber are mutually connected via a gas passage having an outlet hole disposed above the liquid level of the engine oil accumulated at the bottom of the transmission chamber. You may communicate. According to this configuration, the engine oil in the transmission chamber does not flow to the attenuation chamber through the gas passage, and therefore the clogging of the gas passage due to the engine oil can be prevented. Thereby, the flow velocity of the engine oil and air pushed out from the oil passage to the magneto chamber can be appropriately suppressed.

  In the oil lubrication structure of the dry sump type engine of the present invention, the groove constituting the gas passage may be provided in a magnet wall that partitions the magnet chamber. According to this configuration, the gas passage can be provided without sacrificing the rigidity of the partition wall or the like that partitions the crank chamber by providing the groove that constitutes the gas passage in the magneto wall that is not so demanding for rigidity. it can. That is, it is possible to suppress the ripples of the engine oil that accumulates at the bottom of the magneto chamber while maintaining the rigidity of the partition wall or the like that requires high rigidity at a high level.

  In the oil lubrication structure for a dry sump engine according to the present invention, the damping chamber may be disposed above the oil passage. According to this configuration, since the attenuation chamber functions as a gas-liquid separation chamber, the engine oil can be separated from the mixture of air and engine oil flowing into the attenuation chamber and returned to the oil passage.

  ADVANTAGE OF THE INVENTION According to this invention, the oil lubrication structure of the dry sump type engine which suppressed the ripple of the engine oil which accumulates in the lower part of a magneto chamber can be provided.

1 is a left side view showing an appearance of a motorcycle according to the present embodiment. It is a side view which shows the external appearance of the engine unit which concerns on this Embodiment. It is a fragmentary sectional view of the engine unit concerning this embodiment. It is a disassembled perspective view of the crankcase which concerns on this Embodiment. It is a left view of the right crankcase which comprises the crankcase which concerns on this Embodiment. It is a right view of the left crankcase which comprises the crankcase which concerns on this Embodiment. It is a left view of the left crankcase which comprises the crankcase which concerns on this Embodiment. It is sectional drawing of the crankcase which concerns on this Embodiment.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following, an example in which the oil lubrication structure of the dry sump type engine of the present invention is applied to an engine of an off-road type motorcycle will be described, but the application target can be changed without being limited thereto. For example, the oil lubrication structure of the dry sump type engine of the present invention may be applied to engines of other types of motorcycles, automobiles, ships and the like.

  With reference to FIG. 1, the configuration of the entire motorcycle according to the present embodiment will be described. FIG. 1 is a left side view of the motorcycle according to the present embodiment. In the drawings, the front of the vehicle body is indicated by an arrow FR, and the rear of the vehicle body is indicated by an arrow RE.

  As shown in FIG. 1, the motorcycle 1 includes a body frame 2 made of steel or aluminum alloy on which the components of the motorcycle 1 are mounted. The main frame 21 of the vehicle body frame 2 branches from the head pipe 22 located at the front end of the vehicle body frame 2 to the left and right and extends obliquely downward toward the rear of the vehicle body. A down tube 23 extending substantially downward from the head pipe 22 branches to the left and right as a lower frame 24 in the vicinity of the lower part of the vehicle body. The left and right lower frames 24 are further extended downward and then bent toward the rear of the vehicle body, and their rear ends are connected to the left and right rear ends of the main frame 21 via the left and right body frames 25.

  A front fork 31 is rotatably supported at the front end of the vehicle body frame 2 via a steering shaft (not shown) provided in the head pipe 22. A handlebar 32 is coupled to the upper end of the steering shaft, and grips 33 are attached to both ends of the handlebar 32. A clutch lever 34 is disposed on the left front side of the handle bar 32, and a brake lever (not shown) for the front wheel 3 is disposed on the right front side of the handle bar 32. The front wheel 3 is rotatably supported at the lower portion of the front fork 31. The front wheel 3 is provided with a brake disc 35 constituting a brake.

  A swing arm 41 is connected to the body frame 25 of the body frame 2 so as to be swingable in the vertical direction, and a suspension 42 is attached between the body frame 2 and the swing arm 41. The rear wheel 4 is rotatably supported at the rear portion of the swing arm 41. The rear wheel 4 is provided with a rear sprocket (driven sprocket) 43, and the power of the engine is transmitted to the rear wheel 4 by a chain 44.

  A water-cooled engine unit 10 serving as a drive source is mounted at a position near the lower side of the space substantially surrounded by the main frame 21, the down tube 23, the lower frame 24, and the body frame 25 of the vehicle body frame 2. A radiator 5 that is a radiator is disposed in front of the engine unit 10, and an air cleaner box 6 having a filter that separates and collects dust in the air is disposed behind the engine unit 10. A fuel tank 7 in which fuel is stored is disposed above the engine unit 10, and a seat 8 serving as a seat is disposed behind the fuel tank 7. A footrest 81 is provided below the seat 8. A shift pedal 82 is provided in front of the footrest 81 on the left side of the vehicle body, and a brake pedal (not shown) for the rear wheel 4 is provided in front of the footrest 81 on the right side of the vehicle body.

  The engine unit 10 includes a horizontal crank type four-stroke (four-cycle) single-cylinder engine and a transmission (transmission) in which the rotation shaft of the crankshaft is arranged in the vehicle width direction. Air is taken into the engine unit 10 through the air cleaner box 6, the intake pipe 160 (see FIG. 2), etc., and the air and fuel are mixed by the fuel injection device and supplied to the combustion chamber 123 (see FIG. 3). . The combustion gas after combustion is discharged as exhaust gas from the muffler 101 through an exhaust pipe (not shown) extending rearward on the right side surface of the engine unit 10.

  Hereinafter, an outline of the dry sump type engine unit 10 provided with the oil lubrication structure according to the present embodiment will be described with reference to FIGS. 2 and 3. FIG. 2 is a side view showing an overall configuration of engine unit 10 according to the present embodiment. FIG. 3 is a partial cross-sectional view of engine unit 10 according to the present embodiment.

  As shown in FIG. 2, in the engine unit 10, a cylinder 120 is disposed on a crankcase 110, and a cylinder head 130 and a head cover 140 are attached to the cylinder 120. A magnet cover 150 is attached to the left side surface of the crankcase 110, and a clutch cover (not shown) is attached to the right side surface of the crankcase 110.

  As shown in FIG. 3, a crankshaft 112 is accommodated in a crank chamber 111 in the crankcase 110 so that the rotation shaft faces the vehicle width direction. A piston 121 is accommodated in a cylindrical space inside the cylinder 120 so as to reciprocate in the cylinder axis direction (vertical direction). The piston 121 and the crankshaft 112 are connected via a connecting rod (connecting rod) 122 so that the reciprocating motion of the piston 121 is converted into the rotational motion of the crankshaft 112. The piston 121 is connected to the small end portion of the connecting rod 122, and the crankshaft 112 is connected to the large end portion of the connecting rod 122.

  In the cylinder head 130, an intake port 131 that feeds air into the combustion chamber 123 surrounded by the inner wall of the cylinder 120, the lower surface of the cylinder head 130, and the upper surface of the piston 121, and an exhaust port 132 that discharges combustion gas outside the combustion chamber 123. And are provided. Further, the cylinder head 130 is provided with an intake valve 133 for opening and closing the intake port 131 and an exhaust valve 134 for opening and closing the exhaust port 132. An ignition plug (not shown) is provided on the lower surface of the cylinder head 130 so as to protrude, and the air-fuel mixture in the combustion chamber 123 can be ignited by electric discharge.

  In the engine unit 10 that operates in four strokes, the intake valve 133 is opened when the piston 121 descends, and the air-fuel mixture is sent into the combustion chamber 123 through the intake pipe 160 (intake stroke). Thereafter, the intake valve 133 is closed, and the piston 121 rises to compress the air-fuel mixture (compression stroke). When the piston 121 reaches the top dead center, the air-fuel mixture that is ignited and compressed by the spark plug burns (combustion stroke). When the pressure in the combustion chamber 123 increases due to the combustion of the air-fuel mixture, the piston 121 descends. The downward movement of the piston 121 is transmitted to the crankshaft 112 via the connecting rod 122, and the crankshaft 112 rotates. Thereafter, when the piston 121 descends to the bottom dead center and starts to rise again due to inertia, the exhaust valve 134 is opened and the combustion gas is discharged from the exhaust port 132 (exhaust stroke). A valve operating device including an intake valve 133 and an exhaust valve 134 is provided on the upper portion of the cylinder head 130 to enable such an operation.

  The intake / exhaust mechanism of the engine unit 10 is a DOHC (Double Overhead Camshaft) having two independent camshafts on the intake side and the exhaust side. The two camshafts are each provided with a cam having a shape corresponding to the opening / closing timing of the corresponding intake valve 133 or exhaust valve 134 so that the rotation shaft of the camshaft faces the vehicle width direction above the cylinder head 130. Has been placed. One end of the camshaft is connected to the crankshaft 112 via a power transmission mechanism such as a sprocket or cam chain. Thereby, the rotational force of the crankshaft 112 is transmitted to the camshaft, and the intake valve 133 and the exhaust valve 134 are opened and closed to correspond to the rotation of the crankshaft 112.

  The surfaces of the movable parts such as the piston 121 and the crankshaft 112 described above and the parts such as the cylinder 120 that come into contact with the movable parts are lubricated with engine oil in order to prevent wear. The engine oil that has lubricated the piston 121, the crankshaft 112, the cylinder 120, etc. falls due to gravity and collects at the bottom of the crank chamber 111. An oil storage chamber 113 is provided at the bottom of the crank chamber 111 to store the engine oil dropped in this way. The engine oil has functions such as cooling, airtight maintenance, cleaning, and rust prevention in addition to lubrication.

  In the crankcase 110, the oil storage chamber 113 at the bottom of the crank chamber 111 communicates with the oil passage 115 via a reed valve (one-way valve) 114. As a result, when the pressure in the crank chamber 111 is increased by the lowering operation of the piston 121, the reed valve 114 is opened and the engine oil accumulated in the oil storage chamber 113 is discharged to the oil passage 115. Here, the reed valve 114 prevents the backflow of the engine oil discharged to the oil passage 115 into the oil storage chamber 113.

  The engine oil discharged to the oil passage 115 flows into the magneto chamber 151 (see FIGS. 4, 6, and 7) through the oil discharge port H2 (see FIGS. 6 and 7) and accumulates at the bottom of the magneto chamber 151. The engine oil accumulated at the bottom of the magneto chamber 151 is pumped up by an oil pump (scavenge pump) 152 (see FIGS. 4 and 7) and supplied to the transmission chamber 117. An oil pump (feed pump) (not shown) having a rotating shaft that rotates in synchronization with the oil pump 152 is arranged in the transmission chamber 117 so that engine oil can be supplied to each part of the engine unit 10 through an oil passage (not shown). It has become.

  As described above, the engine oil stored in the oil storage chamber 113 is discharged to the oil passage 115 due to the pressure increase in the crank chamber 111. The pressure in the crank chamber 111 increases due to the lowering operation of the piston 121. For example, when the engine speed is high, the piston 121 moves down at a high speed, so that the pressure increase in the crank chamber 111 also becomes abrupt. When the pressure in the crank chamber 111 suddenly rises in this way, the air compressed by the piston 121 and the engine oil are expelled to the oil passage 115 and the engine oil is expelled to the magnet chamber 151 through the oil discharge port H2. It flows in well. As described above, when the flow rate of the engine oil flowing into the magneto chamber 151 is high (large), the liquid level of the engine oil accumulated at the bottom of the magneto chamber 151 violently waves. When the level of the engine oil undulates, it becomes difficult for the oil pump 152 to pump up the engine oil, which may hinder the lubrication of the engine oil.

  The dry sump type engine unit 10 provided with the oil lubrication structure according to the present embodiment has an attenuation chamber 116 that communicates with the oil passage 115 in order to weaken the momentum of the compressed air flowing through the oil passage 115 and the engine oil. . The damping chamber 116 is provided above the oil passage 115 downstream of the reed valve 114 and upstream of the magneto chamber 151 in the engine oil flow path, and a small hole H1 provided to face the opening of the reed valve 114. And communicates with the oil passage 115. With such a configuration, the compressed air ejected from the reed valve 114 can be released to the attenuation chamber 116, so that the flow rates of the compressed air and the engine oil flowing through the oil passage 115 can be kept low (small). As a result, the oil level of the engine oil in the magneto chamber 151 can be suppressed and the engine oil can be lubricated satisfactorily.

  Note that the compressed air released into the attenuation chamber 116 as described above partially contains engine oil. When such a mixture of air and engine oil flows into the attenuation chamber 116, it is separated into air and engine oil in the attenuation chamber 116, and the separated engine oil is returned to the oil passage 115 through the small holes H1. Thus, the attenuation chamber 116 also functions as a gas-liquid separation chamber that separates air and engine oil and returns the engine oil to the oil passage 115.

  The structure of the crankcase 110 will be described in detail with reference to FIGS. FIG. 4 is an exploded perspective view of crankcase 110 (including magnet cover 150 and the like) according to the present embodiment. FIG. 5 is a left side view of the right crankcase 110R constituting the crankcase 110 according to the present embodiment. FIG. 6 is a right side view of the left crankcase 110L constituting the crankcase 110 according to the present embodiment. FIG. 7 is a left side view of the left crankcase 110L. FIG. 8 is a cross-sectional view of crankcase 110 (including magnet cover 150 and the like) according to the present embodiment. 8A shows a cross section corresponding to the cross section taken along arrow AA in FIG. 7, and FIG. 8B shows a cross section corresponding to the cross section taken along arrow BB in FIG. The arrows attached to each room in FIG. 8 indicate the flow of air or engine oil.

  As shown in FIG. 4, the crankcase 110 according to the present embodiment includes a right crankcase 110 </ b> R and a left crankcase 110 </ b> L that are divided into left and right in a plane perpendicular to the vehicle width direction. On the left and right sides of the right crankcase 110R and the left crankcase 110L, walls that constitute the outer shape of the crankcase 110 and that define the respective chambers of the crankcase 110 extend in the vehicle width direction. A wall provided on the left side of the right crankcase 110R and a wall provided on the right side of the left crankcase 110L are joined together to form a crank chamber 111, an oil storage chamber 113, an oil passage 115, an attenuation chamber 116 in the crankcase 110, A transmission chamber 117 and the like are formed. A magneto cover 150 that partitions the magneto chamber 151 is attached to a wall provided on the left side of the left crankcase. In the magnet chamber 151, an oil pump 152 for pumping up engine oil collected at the bottom of the magnet chamber 151 and supplying it to the transmission chamber 117 is disposed. A clutch case (not shown) that partitions the clutch chamber is attached to a wall provided on the right side of the right crankcase.

  As shown in FIG. 5, a right crank wall RW1 that constitutes the outer shape of the front of the crankcase 110 is provided at a position on the left front side of the right crankcase 110R so as to extend in the vehicle width direction. Further, a right transmission wall RW2 constituting an outer shape of the rear of the crankcase 110 is provided at a position on the left rear side of the right crankcase 110R so as to extend in the vehicle width direction. Further, a right partition wall RW3 that partitions the right space in the crankcase 110 into each chamber is provided at a position near the left center of the right crankcase 110R so as to extend in the vehicle width direction.

  As shown in FIG. 6, a left crank wall LW1 that forms an outer shape of the front of the crankcase 110 is provided at a position on the right front side of the left crankcase 110L so as to extend in the vehicle width direction. Further, a left transmission wall LW2 constituting an outer shape of the rear of the crankcase 110 is provided at a right rear position of the left crankcase 110L so as to extend in the vehicle width direction. Further, a left partition wall LW3 that partitions the left space in the crankcase 110 into each chamber is provided at a position near the right center of the left crankcase 110L so as to extend in the vehicle width direction.

  The outer edge of the crankcase 110 is defined by the crank wall formed by joining the right crank wall RW1 and the left crank wall LW1 and the transmission wall formed by joining the right transmission wall RW2 and the left transmission wall LW2. The partition wall formed by joining the right partition wall RW3 and the left partition wall LW3 partitions the space in the crankcase 110 into each chamber. A crank chamber 111 located in front of the crankcase 110 and an oil storage chamber 113 below the crank chamber 111 are defined by the crank wall and the partition wall. A transmission chamber 117 located behind the crankcase 110 is defined by the transmission wall and the partition wall. The partition wall defines an oil passage 115 adjacent to the oil storage chamber 113 and a damping chamber 116 communicating with the oil passage 115 above the oil passage 115.

  As shown in FIG. 7, a magnet wall LW4 constituting the outer shape of the crankcase 110 is provided on the left side of the left crankcase 110L so as to extend in the vehicle width direction. A magneto cover 150 is joined to the left side of the magneto wall LW 4, and a magneto chamber 151 is formed by the magneto wall LW 4 and the magneto cover 150. In addition to the oil pump 152, a stator coil (not shown) and a magnet rotor (not shown) constituting the generator are arranged in the magnet chamber 151.

  As shown in FIGS. 6 to 8, the oil passage 115 defined by the partition wall and the magneto chamber 151 defined by the magneto wall LW4 on the left side of the crankcase 110 communicate with each other via the oil discharge port H2. The engine oil discharged to the oil passage 115 flows into the magneto chamber 151. The engine oil that has flowed into the magnet chamber 151 is pumped up by the oil pump 152 disposed in the magnet chamber 151 so that the oil suction port 152a faces downward, and is discharged from the oil discharge port 152b of the oil pump 152. The oil discharge port 152b of the oil pump 152 is provided at a position corresponding to the oil discharge port H3 of the transmission chamber 117, and the engine oil pumped up by the oil pump 152 flows into the transmission chamber 117 through the oil discharge port H3. It collects at the bottom of the chamber 117.

  As described above, the damping chamber 116 communicating with the oil passage 115 is provided above the oil passage 115. With this configuration, the compressed air in the oil passage 115 can be released to the attenuation chamber 116 (see FIGS. 8A and 8B), so that the flow rates of the compressed air and the engine oil flowing from the oil passage 115 into the magneto chamber 151 are kept low (small). As a result, it is possible to suppress the undulation of engine oil that accumulates at the bottom of the magneto chamber 151. As a result, the oil pump 152 can pump the engine oil well.

  As shown in FIGS. 7 and 8B, a groove D1 is formed in the magneto wall LW4, and a gas passage along the magneto wall LW4 is formed by joining the magneto cover 150 to the magneto wall LW4. It has become so. As shown in FIGS. 6 and 8B, a small hole (inlet hole) H4 is provided at a position corresponding to the lower end of the groove D1 in the attenuation chamber 116, and the attenuation chamber 116 and the gas passage are provided via the small hole H4. Are configured to communicate with each other. A small hole (exit hole) H5 is provided at a position corresponding to the upper end of the groove D1 in the transmission chamber 117, and the transmission chamber 117 and the gas passage are communicated with each other through the small hole H5. . That is, the attenuation chamber 116 and the transmission chamber 117 communicate with each other through the small hole H4, the gas passage formed by the groove D1, and the small hole H5.

  In this configuration, the compressed air ejected from the reed valve 114 also flows into the transmission chamber 117 through the small hole H1, the attenuation chamber 116, the small hole H4, the gas passage, and the small hole H5 (see FIG. 8B). Thus, the transmission chamber 117 (and the gas passage) acts in the same manner as the attenuation chamber 116 because the transmission chamber 117 communicates with the attenuation chamber 116 through the gas passage. That is, since the compressed air ejected from the reed valve 114 can be released to the attenuation chamber 116 and the transmission chamber 117 (including the gas passage), the flow rates of the compressed air and the engine oil flowing through the oil passage 115 are further reduced (smaller). Can be suppressed. As a result, the engine oil level in the magneto chamber 151 can be sufficiently suppressed and the engine oil can be lubricated satisfactorily.

  As shown in FIGS. 8A and 8B, in the crankcase 110 described above, the small hole H5 of the transmission chamber 117 is provided above the level S1 of the engine oil accumulated at the bottom of the transmission chamber 117. For this reason, the engine oil accumulated in the transmission chamber 117 does not flow to the attenuation chamber 116 through the gas passage, and the gas passage can be prevented from being clogged by the engine oil. Thereby, since the compressed air ejected from the reed valve 114 can be released to the transmission chamber 117 through the gas passage, the flow rates of the compressed air and the engine oil flowing through the oil passage 115 can be appropriately suppressed.

  Further, in the crankcase 110, the groove D1 is provided in the magneto wall LW4 that partitions the magneto chamber 151. As described above, since the groove D1 that constitutes the gas passage is provided in the magneto wall LW4 that is not so demanding for rigidity, the rigidity of the partition wall LW3 is the same as when the groove is provided in the partition wall LW3 that partitions the crank chamber 111. Is not sacrificed. For this reason, it is possible to reduce the ripple of engine oil that accumulates at the bottom of the magnet chamber 151 while maintaining the rigidity of the partition wall LW3 that partitions the crank chamber 111 at a high level.

  As described above, according to the oil lubrication structure of the dry sump engine according to the present invention, the air discharged from the one-way valve can be released out of the oil passage by providing the damping chamber upstream of the magneto chamber. The flow rate of the engine oil and air pushed out from the oil passage to the magneto chamber can be suppressed. Thereby, the ripple of the engine oil which accumulates at the bottom of the magneto chamber can be suppressed.

  In addition, this invention is not limited to description of the said embodiment, It can change suitably and implement, without deviating from the scope of the present invention. For example, in the above-described embodiment, the groove constituting the gas passage is provided in a part of the magneto wall located behind the magneto chamber in the crankcase, but the groove may be provided in the magneto wall or the like located above the magneto chamber. . Further, the gas passage is not limited to communicating with the transmission chamber, and may communicate with other chambers. Further, the shape, size, quantity, and the like of the small hole for communicating the oil passage and the attenuation chamber are not particularly limited.

  The oil lubrication structure of a dry sump type engine according to the present invention is useful for an engine of a motorcycle, for example.

DESCRIPTION OF SYMBOLS 1 Motorcycle 2 Body frame 3 Front wheel 4 Rear wheel 5 Radiator 6 Air cleaner box 7 Fuel tank 8 Seat 10 Engine unit 110 Crankcase 111 Crank chamber 112 Crankshaft 113 Oil storage chamber 114 Lead valve (one-way valve)
115 Oil passage 116 Damping chamber 117 Transmission chamber 120 Cylinder 121 Piston 122 Connecting rod (connecting rod)
123 Combustion chamber 130 Cylinder head 131 Intake port 132 Exhaust port 133 Intake valve 134 Exhaust valve 140 Head cover 150 Magnet cover 151 Magnet chamber 152 Oil pump 152a Oil intake port 152b Oil discharge port 160 Intake pipe D1 Grooves H1, H4, H5 Small hole H2 , H3 oil outlet

Claims (5)

In a dry sump type engine in which engine oil that accumulates at the bottom of the crank chamber is discharged to the magneto chamber through a one-way valve,
An oil passage for guiding engine oil discharged through the one-way valve to the magneto chamber downstream from the one-way valve and upstream from the magneto chamber;
An oil lubrication structure for a dry sump type engine, comprising: an attenuation chamber that communicates with the oil passage and is configured to suppress flow rates of engine oil and air flowing into the magneto chamber from the oil passage.   2. The oil lubrication structure for a dry sump type engine according to claim 1, wherein the damping chamber communicates with a transmission chamber provided in the dry sump type engine.   3. The damping chamber and the transmission chamber are communicated with each other via a gas passage having an outlet hole disposed above the level of engine oil accumulated at the bottom of the transmission chamber. Oil lubrication structure for dry sump type engines.   4. The oil lubrication structure for a dry sump type engine according to claim 3, wherein the groove constituting the gas passage is provided in a magneto wall defining the magneto chamber.   5. The oil lubrication structure for a dry sump engine according to claim 1, wherein the damping chamber is disposed above the oil passage. 6.

Images