JP6919489B2 - Engine lubrication path structure - Google Patents

Description

The present invention relates to an engine lubrication path structure.

The oil that lubricates and cools the pistons, cylinders, and crankshafts in the engine flows downward in the crank chamber and is accompanied by the crankshafts and crankwebs arranged in the crank chambers. In particular, in a single-cylinder engine that is required to be compact, the side wall of the crankcase and the outer surface of the crank web are close to each other, so that the oil existing between them causes drag resistance to the crankshaft and crank web. There is a risk that the mechanical loss of the engine will increase due to the occurrence of rotational resistance (resistance due to the viscosity of the oil).

Patent Document 1 discloses a technique in which an oil discharge groove for discharging oil to an oil reservoir is provided on a side wall of a crankcase facing the outer surface of a crank web in the crank chamber of an engine.

Japanese Unexamined Patent Publication No. 2013-96292

According to the technique described in Patent Document 1, the oil in the oil discharge groove is discharged to the oil sump chamber by the rotating crank web, so that the oil accumulated in the crankshaft and the crank chamber accommodating the crank web is reduced. Therefore, the rotational resistance of the crankshaft due to oil can be reduced. However, in the technique described in Patent Document 1, there is no mechanism for recovering the oil scattered in the radial direction of the crankshaft by the crankweb due to the rotation of the crankshaft and the oil flowing down from the cylinder above the crank chamber. , All of these oils are flowing into the crank chamber.

An object of the present invention has been made in consideration of the above circumstances, and the oil flowing between the crank web provided on the crankshaft and the side wall of the crankcase is efficiently recovered and reduced in front of the crankweb. It is an object of the present invention to provide an engine lubrication path structure capable of reducing the rotational resistance of a crankshaft due to oil and reducing the mechanical loss of the engine.

The engine lubrication path structure according to the present invention includes a crankshaft provided with a crankweb, a crankchair in which the rotation axis of the crankshaft is positioned in the left-right direction to accommodate the crankshaft, and the crank that communicates with the crankshaft. In an engine having a crankcase provided below the chamber and provided with an oil reservoir for storing oil, inside the crankcase, above and in front of the rotation axis of the crankshaft, and of the crankweb. A convex member provided so as to project near the outer peripheral surface, a recovery groove formed in the convex member and opened upward to collect oil, and a crankcase formed in the crankcase, and an inflow port opens in the recovery groove. The outlet is opened to an oil discharge mechanism provided in the lower part of the crankcase, and has an oil discharge passage for guiding oil to the oil reservoir by the action of the oil discharge mechanism. ..

According to the present invention, the oil flowing down from the cylinder installed on the upper part of the crankcase and the oil scattered in the radial direction of the crankshaft due to the rotation of the crankshaft are collected by the collection groove of the convex member, and the oil discharge passage and the oil discharge passage and the oil discharge passage and the oil are collected. It can be discharged to the oil sump chamber via the oil discharge mechanism. As a result, the oil flowing between the crankweb of the crankshaft and the side wall of the crankcase can be efficiently collected and reduced in front of the crankshaft, and the rotational resistance of the crankshaft due to the oil is reduced to reduce the rotational resistance of the engine. The mechanical loss can be reduced.

The left side sectional view which shows the engine to which one Embodiment in the lubrication path structure of the engine which concerns on this invention is applied. FIG. 2 is a cross-sectional view taken along the line II-II of FIG. A perspective view showing the right crankcase, the crankshaft, and the like of FIGS. 1 and 2 visually from diagonally left front. FIG. 3 is a perspective view showing the right crankcase of FIG. 3 visually from diagonally left rearward. The left side view of a part of the right crankcase of FIGS. 1 and 4 in an enlarged manner.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.
FIG. 1 is a left sectional view showing an engine to which one embodiment in the lubrication path structure of the engine according to the present invention is applied. Further, FIG. 2 is a cross-sectional view taken along the line II-II of FIG. The front-rear, left-right, and up-down expressions in this embodiment are based on the occupants riding in the motorcycle equipped with the engine of the present embodiment.

The engine 10 shown in FIGS. 1 and 2 is a 4-cycle single-cylinder engine mounted on a saddle-mounted vehicle such as a motorcycle, and is configured by installing a cylinder assembly 12 in a crankcase 11 with a slight forward tilt. .. The cylinder assembly 12 is configured by fitting a substantially cylindrical cylinder 13 into the upper part of the crankcase 11 and arranging the cylinder head 14 and a head cover (not shown) in this cylinder 13 in order.

The crankcase 11 can be divided in the width direction (left-right direction) of the engine 10 and in the rotation axis O direction of the crankshaft 18. That is, the crankcase 11 is configured by connecting the left crankcase 11L and the right crankcase 11R, and the crankcase 15, the oil sump chamber 16, and the transmission chamber 17 are formed by this coupling. The crankshaft 18 is rotatably housed in the crank chamber 15 with its rotation axis O positioned in the width direction (left-right direction) of the engine 10. Further, the oil sump chamber 16 communicates with the crank chamber 15 below the crank chamber 15 via the oil discharge port 19 and stores oil (engine oil) as lubricating oil. Further, a deceleration mechanism (not shown) is housed in the mission chamber 17.

The crankshaft 18 is configured such that a rotary shaft portion 20 coaxial with the rotary shaft O and a crank web 21 are integrally formed, and these crank webs 21 are connected by a crank pin 22. The crank web 21 includes an outer surface 21A perpendicular to the rotation axis O of the crankshaft 18. In the crankshaft 18, the rotary shaft portion 20 is rotatably supported by the side wall 24 of the crankcase 11 via the bearing 23. The side wall 24 is a side wall forming a crank journal portion in the crankcase 11 (left crankcase 11L, right crankcase 11R), and a bearing 23 is installed on the side wall 24.

Each side wall 24 of the left crankcase 11L and the right crankcase 11R has an inner surface substantially perpendicular to the rotation axis O of the crankshaft 18. The inner surface of the side wall 24 is arranged so as to face and approach the outer surface 21A of the crank web 21 on the crankshaft 18. As a result, the volume of the crank chamber 15 is set to the minimum, and the engine 10 can be made compact.

The piston 26 is housed in the cylinder 13 so as to be reciprocating in the axis P direction of the cylinder 13. The piston 26 and the crankshaft 18 are connected by a connecting rod 27, and the reciprocating motion of the piston 26 is converted into the rotational motion of the crankshaft 18. Here, the rotation direction of the crankshaft 18 is indicated by an arrow R in FIGS. 1 and 3. Further, the small end portion of the connecting rod 27 is swingably connected to the piston 26 via the piston pin 28. The large end of the connecting rod 27 is swingably connected to the crankshaft 18 via the crankpin 22.

Inside the cylinder head 14, there is an intake port 30 that supplies a mixture of fuel and air to the combustion chamber 29 surrounded by the inner wall surface of the cylinder 13, the lower surface of the cylinder head 14, and the upper surface of the piston 26, and the outside of the combustion chamber 29. An exhaust port 31 for discharging the combustion gas to the cylinder is formed. Further, in the cylinder head 14, an intake valve 32 that opens and closes the intake port 30, an exhaust valve 33 that opens and closes the exhaust port 31, and a valve operating mechanism (not shown) that drives these intake valve 32 and the exhaust valve 33 are installed. Has been done.

In the engine 10 configured as described above, each part of the engine 10, for example, a sliding portion between the cylinder 13 and the piston 26, shaft portions (piston pin 28, crank pin 22) at both ends of the conrod 27, and a crankshaft 18. The bearing portion (bearing 23) is lubricated with oil, and the inner surface of the cylinder 13 and the piston 26 facing the combustion chamber 29 are cooled by the oil.

In particular, as an oil jet on the upper part of the crank chamber 15 for lubrication of the sliding portion between the cylinder 13 and the piston 26, the shaft portion (piston pin 28) between the connecting rod 27 and the piston 26, and cooling of the piston 26. Piston jet 35 (FIGS. 3 and 4) is provided. The piston jet 35 is opened in a rib 36 as a convex member provided on the front wall of the crankcase 11 (left crankcase 11L, right crankcase 11R) so as to project rearward, or has a nozzle shape (the present embodiment). Then, it is formed (opened) and the oil sent by the oil pump is injected. Specifically, the piston jet 35 injects oil toward the back surface of the piston 26. The rib 36 is formed so as to extend along the direction of the rotation axis O of the crankshaft 18, and supplies oil from the oil passage 37 (FIG. 5) formed on the upper portion of the side wall 24 of the crankcase 11 to the piston jet 35. An oil supply passage 38 for the purpose is provided inside.

As shown in FIGS. 1 and 2, the oil that lubricates and cools each part of the engine 10 such as the cylinder 13, the piston 26, and the crankshaft 18 is supplied to the inside of the crankcase 15 and the oil recovery device 40 (FIG. 5) described later. After that, the oil is stored in the oil storage chamber 16 at the bottom of the crankcase 11. The oil stored in the oil sump chamber 16 is sent out by an oil pump (not shown) and is supplied again to each part of the engine 10.

As shown in FIGS. 1 and 5, the above-mentioned oil recovery device 40 collects the oil flowing down or falling from above the crank chamber 15 at the upper part of the crank chamber 15, and in the crank chamber 15, the crankcase 11 The amount of oil flowing between the side wall 24 and the outer surface 21A of the crankweb 21 of the crankshaft 18 is reduced, and the rib 36, the recovery groove 41, the slope portion 42, the oil discharge passage 43, and the oil discharge mechanism 44 are provided. Consists of having.

As described above, the rib 36 is provided on the front wall of the crankcase 11 (left crankcase 11L, right crankcase 11R) in the upper part of the crankcase 15. Specifically, inside the crankcase 11 (left crankcase 11L, right crankcase 11R), above and in front of the rotation axis O of the crankshaft 18, and in the vicinity of the outer peripheral surface 21B of the crankweb 21, this outer peripheral surface. It is provided at a position below the uppermost position of 21B. Then, the rib 36 projects rearward and extends along the rotation axis O direction of the crankshaft 18.

As shown in FIGS. 1, 3 and 4, the recovery groove 41 is formed on the upper surface of the rib 36 along the left-right direction (along the rotation axis O direction of the crankshaft 18). In order to form the recovery groove 41, a flange protruding upward can be provided at the tip (rear end) of the rib 36. In the present embodiment, the recovery groove 41 is formed by utilizing the upward bulging shape for incorporating the oil supply passage 38 instead of providing the flange. That is, it is formed as a recess extending in the left-right direction that opens upward on the upper surface of the rib 36 between the inner surface of the front wall of the crankcase 11 and the bulging shape of the oil supply passage 38 in the front-rear direction of the vehicle. Therefore, like the rib 36, the recovery groove 41 is located above and in front of the rotation axis O of the crankshaft 18 and in the vicinity of the outer peripheral surface 21B of the crankweb 21 and below the uppermost position of the outer peripheral surface 21B. Provided. The recovery groove 41 is formed on the upper surface of the rib 36 along the rotation axis O direction of the crankshaft 18, and the oil flowing down from the inner surface of the cylinder 13 and the crankshaft 18 due to the rotation of the crankshaft 18 cause the crankshaft 18 to flow down. The oil scattered in the radial direction of is captured and recovered. Further, the tip of the rib 36 is arranged in the vicinity of the outer peripheral surface 21B of the crank web 21, and scrapes off the oil that accompanies the crank web 21.

As shown in FIGS. 2 and 3, the slope portion 42 has a substantially cylindrical cylinder accommodating portion 25 into which the cylinder 13 is fitted and a cylinder accommodating portion 25 in the crankcase 11 (left crankcase 11L, right crankcase 11R). It is a vertical wall narrower than the width and is arranged at the boundary with the side wall 24 on which the crankshaft 18 is supported. The slope portion 42 is formed so as to be continuous with the lower end of the inner surface of the cylinder accommodating portion 25 and continuous with the upper end portion of the side wall 24. That is, the dimensions of both crankwebs 21 in the rotation axis O direction are set narrower than the inner diameter of the cylinder accommodating portion 25, and the crankcase 11 (left crankcase 11L, right) is further approached to the outer surface 21A of the crankweb 21. The side wall 24 of the crankcase 11R) is arranged. For this reason, a slope portion 42 is continuously formed on the wall surface of the cylinder accommodating portion 25 at the upper end portion of the side wall 24.

The slope portion 42 is arranged below the cylinder 13 fitted into the cylinder accommodating portion 25, and is set so as to be inclined obliquely downward from the inner surface of the cylinder accommodating portion 25 toward the crank web 21. Further, the lower end edge 42A of the slope portion 42 on the crank web 21 side is positioned below the uppermost position of the outer peripheral surface 21B of the crank web 21. That is, the upper portion of the crank web 21 is arranged so as to project upward from the lower end edge 42A of the slope portion 42. As a result, as shown by arrows A in FIGS. 3 and 4, a part of the oil flowing down on the slope portion 42 flows between the crank web and the side wall of the crankcase when it reaches the crank web 21. Previously, the rotation of the crank web 21 causes the crankshaft 18 to scatter in the radial direction. Further, a part of the oil flowing down on the slope portion 42 adheres to the crank web 21 when it reaches the crank web 21, is carried to the rib 36 arranged in the vicinity of the outer peripheral surface 21B, and is scraped off.

Further, as shown in FIGS. 1, 3 and 4, the cylinder assembly 12 is installed so as to be tilted forward with respect to the crankcase 11, and the cylinder assembly 12 is vertically mounted when the engine 10 is mounted on a motorcycle. When the slope portion 42 is tilted forward with respect to the direction, the front side of the slope portion 42 is lowered when the engine 10 is mounted on the motorcycle. The lower end edge 42A of the slope portion 42 is lowered on the front side when mounted on a motorcycle. That is, the slope portion 42 is configured to be inclined diagonally forward and downward toward the recovery groove 41 to guide the oil to the recovery groove 41. Further, the lower end edge 42B on the recovery groove 41 side of the lower end edge 42A of the slope portion 42 is provided at a position continuous with the recovery groove 41 or at a position higher than the recovery groove 41. That is, the recovery groove 41 is arranged below the lower end edge 42A of the slope portion 42. Then, as shown by the arrow B in FIGS. 3 and 4, a part of the oil flowing on the slope portion 42 is guided to the recovery groove 41 by such an arrangement configuration.

As shown in FIGS. 4 and 5, the oil discharge passage 43 is formed inside the side wall 24 of at least one of the left crankcase 11L and the right crankcase 11R (right crankcase 11R in this embodiment) in the crankcase 11. ing. Further, it is formed at a position where it partially overlaps with the crank web 21 in the side view of the engine 10 (view in the direction of the rotation axis of the crankshaft 18). The oil discharge passage 43 reaches the recess 50 described later of the oil discharge mechanism 44 provided below the rotation shaft O of the crankshaft 18 from the recovery groove 41, and forms the first machined hole 45 and the second machined hole 46 which are continuous with each other. Consists of having.

The first drilled hole 45 is drilled downward from the cylinder accommodating portion 25 side of the crankcase 11 with respect to the recovery groove 41 of the rib 36, and the upper end becomes an inflow port 47 that opens into the recovery groove 41. Further, the second machined hole 46 is drilled from the outside of the crankcase 11 toward the recess 50 of the oil discharge mechanism 44, communicates with the first machined hole 45, and the lower end opens to the front surface forming the recess 50. It becomes the outlet 48. The upper end of the second machined hole 46 is closed by inserting the stopper 49. The oil recovered in the recovery groove 41 flows into the oil discharge passage 43 and flows into the recess 50 of the oil discharge mechanism 44.

The oil discharge mechanism 44 is provided in the lower part of the crank chamber 15 as shown in FIGS. 1, 4 and 5, and has a recess 50. The recess 50 is formed at the lower part of the side wall 24 in at least one of the left crankcase 11L and the right crankcase 11R of the crankcase 11 (right crankcase 11R in this embodiment) so as to face the outer surface 21A of the crankweb 21. NS. Further, the recess 50 is formed in an arc shape centered on the rotation axis O of the crankshaft 18 on the upstream side of the oil discharge port 19 in the rotation direction R of the crankshaft 18. Further, the recess 50 is formed deeper as it approaches the rear surface on the oil discharge port 19 side, and the outlet 48 of the oil discharge passage 43 opens to the front surface as described above. The oil discharge port 19 is formed at the lower part of the crankcase 11 so as to face the outer peripheral surface 21B of the crankweb 21 and open toward the upstream side in the rotation direction R of the crankshaft 18.

The oil that has flowed out from the outflow port 48 of the oil discharge passage 43 into the recess 50 flows to the oil discharge port 19 side and is discharged into the oil sump chamber 16. Further, it flows to the crank web 21 side which rotates by the rotation of the crankshaft 18, is pushed out to the oil discharge port 19 side by the crank web 21, and is discharged into the oil sump chamber 16 together with the oil in the crank chamber 15. NS. The oil in the recess 50 is pulled out by the action of the rotating crank web 21 and pushed out to the oil discharge port 19 side, so that the flow of the oil in the oil discharge passage 43 becomes smooth and the amount of oil conveyed increases. , Is discharged to the oil sump 16 through the recess 50 and the oil discharge port 19. The oil drawn out from the recess 50 by the action of the crank web 21 is scraped off at the opening edge of the oil discharge port 19 and flows into the oil discharge port 19. By opening the outlet 48 of the oil discharge passage 43 to the front surface of the recess 50, it becomes easy to form a surface substantially perpendicular to the processing direction, and the hole processing of the second processing hole 46 becomes easy. The life of the cutting tool is extended and the productivity is improved.

Since it is configured as described above, according to the present embodiment, the following effects (1) to (3) are obtained.
(1) As shown in FIGS. 1, 4 and 5, inside the front wall of the crankcase 11 (left crankcase 11L, right crankcase 11R), above and in front of the rotation axis O of the crankshaft 18. Moreover, the rib 36 is provided so as to project near the outer peripheral surface 21B of the crank web 21. A recovery groove 41 that opens upward to collect oil is formed on the upper surface of the rib 36. Further, in the right crankcase 11R of the crankcase 11, an oil discharge passage 43 opens the inflow port 47 into the recovery groove 41, and the outflow port 48 is a recess of the oil discharge mechanism 44 provided in the lower part of the crankcase 15. It is formed by opening to 50. Then, by the action of the rotational movement of the crank web 21 in the oil discharge mechanism 44, the oil that has flowed out from the oil discharge passage 43 into the recess 50 is guided to the oil sump chamber 16.

Therefore, the oil flowing down from the cylinder 13 installed in the cylinder accommodating chamber 25 above the crankcase 11 and the oil scattered in the radial direction of the crankshaft 18 by the crankweb 21 due to the rotation of the crankshaft 18 are supplied to the rib 36. It can be collected by the collection groove 41 and discharged to the oil sump chamber 16 through the oil discharge passage 43 and the oil discharge mechanism 44 (recessed portion 50). As a result, the oil flowing between the outer surface 21A of the crank web 21 and the side wall 24 of the crankcase 11 can be efficiently recovered and reduced in front of the oil, so that the rotational resistance of the crankshaft 18 due to the oil can be reduced. It can be reduced to reduce the mechanical loss of the engine 10 and improve the output and fuel consumption of the engine 10.

(2) As shown in FIGS. 2 and 3, on the side wall 24 of the crankcase 11 (left crankcase 11L, right crankcase 11R), from the cylinder 13 arranged in the cylinder accommodating portion 25 toward the crank web 21. A slope portion 42 that inclines diagonally downward is provided. The slope portion 42 is further inclined toward the recovery groove 41 of the rib 36 projecting from the front wall of the crankcase 11 (left crankcase 11L, right crankcase 11R) when the engine 10 is mounted on the motorcycle. It is configured to incline forward and downward to guide the oil to the recovery groove 41. Therefore, a part of the oil that has fallen or flowed down to the slope portion 42 is scattered by the crank web 21, and the remaining portion is collected in the recovery groove 41. Therefore, the recovery of the oil by the recovery groove 41 is efficient. Can be implemented.

(3) As shown in FIG. 4, the recovery groove 41 for collecting the oil is formed on the upper surface of the rib 36 provided for forming the oil supply passage 38 for supplying the oil to the piston jet 35, and therefore the recovery groove 41 is formed. It is not necessary to provide a dedicated rib in the groove 41. Therefore, the structure of the crankcase 11 is not complicated, and it is possible to avoid an increase in the size of the engine 10.

Although the embodiment of the present invention has been described above, this embodiment is presented as an example and is not intended to limit the scope of the invention. This embodiment can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention, and the replacements and changes thereof can be made. , It is included in the scope and gist of the invention, and is also included in the scope of the invention described in the claims and the equivalent scope thereof.

For example, in the present embodiment, the case where the present invention is applied to an engine mounted on a motorcycle is described, but the present invention is applied to an engine mounted on a motorcycle, an all-terrain vehicle, a motorcycle, or the like. You may.

10 ... Engine, 11 ... Crankcase, 13 ... Cylinder, 15 ... Crank chamber, 16 ... Oil reservoir, 18 ... Crankshaft, 21 ... Crankweb, 21A ... Outer surface, 21B ... Outer surface, 24 ... Side wall, 35 ... Piston jet (oil jet), 36 ... rib (convex member), 38 ... oil supply passage, 40 ... oil recovery device, 41 ... recovery groove, 42 ... slope, 42A, 42B ... lower edge, 43 ... oil discharge passage, 44 ... Oil discharge mechanism, 47 ... Inlet, 48 ... Outlet, 50 ... Recess, O ... Rotating shaft.

Claims (5)

A crankshaft with a crank web and
A crankcase in which the rotation axis of the crankshaft is positioned in the left-right direction to accommodate the crankshaft, and a crankcase having an oil reservoir that communicates with the crankshaft and is provided below the crankshaft to store oil. In an engine with
A convex member provided inside the crankcase, above and in front of the rotation axis of the crankshaft, and protruding near the outer peripheral surface of the crankweb.
A collection groove formed in this convex member that opens upward to collect oil,
Formed in the crankcase, the inflow port opens in the recovery groove, the outflow port opens in the oil discharge mechanism provided in the lower part of the crank chamber, and the oil is discharged to the oil sump chamber by the action of the oil discharge mechanism. An engine lubrication path structure, characterized in that it has an oil drainage passage that guides it. The crankcase is provided with a slope portion that inclines diagonally downward from a cylinder installed on the upper part of the crankcase toward the crank web, and the lower end edge of the slope portion on the crank web side is the outer periphery of the crank web. The engine lubrication path structure according to claim 1, wherein the engine is positioned below the top position of the surface. The slope portion is configured to incline diagonally downward toward the recovery groove to guide the oil to the recovery groove, and the lower end edge of the slope portion on the recovery groove side is continuous with the recovery groove, or the said. The engine lubrication path structure according to claim 2, wherein the engine is provided at a position higher than the recovery groove. The oil discharge mechanism includes a recess formed below the side wall of the crankcase forming the crank chamber and facing the side surface of the crank web, and the crank web, and the recess has an oil discharge passage. The outlet opens,
The invention according to any one of claims 1 to 3, wherein the oil flowing out from the outlet to the recess is discharged to the oil sump chamber of the crankcase by the rotational movement of the crank web. The engine lubrication path structure described. The convex member is a rib on which an oil supply passage for supplying oil to the oil jet is formed, and a recovery groove is provided between the oil supply passage and the front wall of the crankcase on the upper surface of the rib. The engine lubrication path structure according to any one of claims 1 to 4.

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