WO2015146672A1

WO2015146672A1 - Engine lubrication structure

Info

Publication number: WO2015146672A1
Application number: PCT/JP2015/057683
Authority: WO
Inventors: 文則水谷
Original assignee: 本田技研工業株式会社
Priority date: 2014-03-28
Filing date: 2015-03-16
Publication date: 2015-10-01
Also published as: JPWO2015146672A1; CN106164425B; JP6117990B2; PH12016501707B1; MY177190A; CN106164425A; PH12016501707A1

Abstract

An engine lubrication structure equipped with: a crankcase formed by a pair of half-cases divided at a dividing surface; an cylinder block; and an oil supply path. The oil supply path is equipped with: a first oil passage; a second oil passage; a first bypass hole, one end of which communicates with the first oil passage and the other end of which communicates with a region of the divided surface that is separated from the joining surface between one of the half-cases and the cylinder block; and a second bypass hole, one end of which communicates with the second oil passage and the other end of which communicates with a region of the divided surface that is separated from the joining surface between the other half-case and the cylinder block. The other end of the first bypass hole and the other end of the second bypass hole are connected so as to communicate with each other in the divided surface.

Description

Engine lubrication structure

The present invention relates to an engine lubrication structure for supplying lubricating oil to a portion of the engine that requires lubrication.
This application claims priority based on Japanese Patent Application No. 2014-070275 filed on Mar. 28, 2014, the contents of which are incorporated herein by reference.

Many engines used in vehicles require oil in the oil pan to be sucked up by an oil pump installed in the crankcase and lubricated in the engine from the oil pump through the oil supply passage formed in the crankcase and cylinder block. Supply oil to the site.

Further, as an engine lubrication structure, a structure in which a part of an oil supply path is provided at a joint surface portion between a crankcase and a cylinder block is known (see, for example, Patent Document 1).
In the engine lubrication structure described in Patent Document 1, a passage groove having a predetermined length curved around the center axis of the cylinder is formed on the joint surface on the crankcase side of the joint surfaces of the crankcase and the cylinder block. And when a crankcase and a cylinder block are joined, a part of oil supply path is comprised between both joint surfaces. In the case of the engine described in Patent Document 1, the crankcase is formed by joining a pair of case halves divided by a dividing surface orthogonal to the crankshaft, and the passage groove is formed on one case half side. It is formed only in the range of the joint surface with the cylinder block.

Japanese Unexamined Patent Publication No. 2007-170314

By the way, in an engine in which a crankcase is configured by connecting a pair of case halves, when an oil supply path is formed so as to straddle between the joint surfaces of the cylinder block and each case halves, the three members come into contact with each other. Therefore, high processing accuracy and sealing performance are required to prevent oil leakage from the oil supply path. For this reason, as in the lubricating structure described in Patent Document 1, the oil supply path is formed only in the range of the joint surface between the cylinder block and one case half (in a range not exceeding the split surface between the case halves). Often done. However, in this case, the degree of freedom in designing the oil supply path is limited.

An aspect of the present invention provides an engine lubrication structure capable of easily forming an oil supply path straddling a joint surface between a cylinder block and a pair of case halves and increasing the degree of freedom in designing the oil supply path. provide.

In order to solve the above problems, the present invention employs the following aspects.
(1) An engine lubrication structure according to an aspect of the present invention includes a crank that rotatably supports a crankshaft and joins a pair of case halves divided by a split surface that intersects the crankshaft to each other. A case, a piston that reciprocates, a cylinder block that is joined across an end surface that intersects the split surface of each case half of the crankcase, and is formed from the crankcase to the cylinder block; An oil supply path that supplies oil supplied from an oil supply source on the crankcase side to a portion that needs lubrication in the engine, and the oil supply path flows in oil from the oil supply source A first oil passage formed between the joint surfaces of the cylinder block and one case half of the crankcase; A second oil passage formed between the joint surfaces of the cylinder block and the other case half of the crankcase, and one end of the first oil passage. A first bypass hole formed in the one case half so that the other end is connected to a portion of the split case separated from the joint surface of the one case half with the cylinder block. The other case half so that one end is conducted to the second oil passage and the other end is conducted to a portion of the other case half separated from the joint surface with the cylinder block. And the other end of the first bypass hole and the other end of the second bypass hole are connected to each other on the dividing surface.

As a result, the first oil passage and the second oil passage are connected to each other via the first bypass hole and the second bypass hole, which are connected to each other at the divided surface portion separated from the joint surface of the cylinder block and the crankcase. Is done. Therefore, the oil supply path is not connected across the joint of the three members. For this reason, it is possible to easily form an oil supply path across the joint surface between the cylinder block and the pair of case halves.

(2) In the aspect of the above (1), the first oil passage and the second oil passage are arranged such that the inflow portion and the outflow portion overlap a diagonal line passing through the cylinder central axis of the cylinder block. It may be formed.

As a result, even when the inflow portion and the outflow portion are arranged in a diagonal position farthest around the cylinder center axis, the first oil passage and the second oil passage are connected to the first bypass hole and the first bypass passage. 2 By connecting through the bypass hole, oil leakage can be easily prevented.

(3) In the aspect of the above (2), the cylinder block is fastened and fixed to the crankcase by a plurality of fastening members, and the insertion hole of the fastening member formed in the cylinder block is centered on the cylinder central axis. Arranged on the same pitch circle, at least a part of each of the inflow portion and the outflow portion may be disposed in a region radially outside the pitch circle and in the vicinity of the insertion hole. .

In this case, even if the inflow portion of the first oil passage and the outflow portion of the second oil passage are arranged in the radially outer region than the pitch circle in which the insertion hole formed in the cylinder block is arranged, the inflow portion The cylinder block and the crankcase are tightly adhered to each other in the vicinity of the part and the outflow part by tightening the fastening member. Therefore, oil leakage from these parts can be efficiently prevented.

(4) In the aspect according to any one of (1) to (3) above, the crankcase is integrally provided with a transmission accommodating portion for accommodating a transmission, and the first bypass hole and the first A branch oil passage that branches from at least one of the two bypass holes and supplies oil to the transmission may be formed.

In this case, the branch oil passage for supplying oil to the transmission branches from at least one of the first bypass hole and the second bypass hole. Therefore, it is possible to partially use a passage and a passage for supplying oil to the cylinder block side. Accordingly, the structure of the oil passage of the entire engine including the transmission portion can be simplified.

(5) In the aspect of the above (4), the branch oil passage is branched from a side surface of an extension portion extending downward from a lower end of at least one of the first bypass hole and the second bypass hole. Also good.

In this case, since the branch oil passage is branched from the side surface of the extension portion extending downward, the foreign matter mixed in the oil is allowed to settle on the bottom portion of the extension portion, making it difficult to enter the branch oil passage side. . Accordingly, foreign matters can be removed from the oil supplied to the transmission side.

(6) In the above aspect (4) or (5), a part of the branch oil passage is constituted by a passage groove formed on at least one of the pair of case halves so as to face the dividing surface. Anyway.

In this case, the passage groove is formed facing the dividing surface of the case half. Therefore, even a relatively complicated passage shape can be easily formed by cutting from a divided surface.

(7) In the aspect of the above (6), the oil leaking outside the passage groove is captured in the outer region of the passage groove in the outer wall of the crankcase, and returned to the crankcase. It is preferable that a groove is provided.

In this case, even if oil leaks to the outside of the passage groove, the oil is captured by the capture groove and returned to the crankcase. Therefore, oil leakage from the crankcase can be efficiently prevented.

(8) In the above aspect (6) or (7), an orifice portion is provided upstream of the passage groove of the branch oil passage, and the orifice portion is an orifice formed at the bottom of the passage groove. You may be comprised by the hole.

In this case, an orifice hole can be easily formed in the bottom of the passage groove of the crankcase by drilling or the like, and the number of parts can be reduced compared to the case where the orifice part is configured by incorporating an orifice part. Can do.

According to the aspect of the present invention, the first oil passage between the cylinder block and the one case half, and the second oil passage between the cylinder block and the other case half are the cylinder block, They are connected via the first bypass hole and the second bypass hole that are connected to each other at the dividing surface portion of each case half that is separated from the joint surface. Therefore, it is possible to easily form an oil supply path over the joint surface between the cylinder block and the pair of case halves without requiring extremely high processing accuracy and sealing performance for preventing oil leakage. Therefore, according to the aspect of the present invention, the degree of freedom in designing the oil supply path can be increased.

1 is a left side view of a motorcycle employing a power unit according to an embodiment of the present invention. It is a right view of the power unit of one Embodiment of this invention. It is a left view of the power unit of one Embodiment of this invention. It is a top view of the power unit of one embodiment of this invention. FIG. 5 is a cross-sectional view substantially corresponding to the VV cross section of FIG. 2 of the power unit according to the embodiment of the present invention. FIG. 4 is a cross-sectional view substantially corresponding to the VI-VI cross section of FIG. 2 of the power unit according to the embodiment of the present invention. It is a bottom view corresponding to the VII arrow of FIG. 2 of the cylinder block of one Embodiment of this invention. FIG. 8 is a partial cross-sectional perspective view in which the power unit according to the embodiment of the present invention is taken along the line VIII-VIII in FIG. 7. It is a perspective view of the case half of the right side of the crankcase of one embodiment of this invention. It is a perspective view of the case half of the left side of the crankcase of one embodiment of this invention. It is a top view centering on the direct upper part of the main axis | shaft of the power unit of one Embodiment of this invention. FIG. 12 is a partial cross-sectional perspective view in which the rotation sensor of the power unit according to the embodiment of the present invention is removed and the cross section is taken along the XII-XII portion of FIG. It is the perspective view which removed the rotation sensor of the power unit of one Embodiment of this invention. It is sectional drawing corresponding to the XIV-XIV cross section of FIG. 11 of the power unit of one Embodiment of this invention. FIG. 15 is a cross-sectional view corresponding to the XV-XV cross section of FIG. 11 of the power unit according to the embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings used for the following description, an arrow FR indicating the front of the vehicle, an arrow LH indicating the left side of the vehicle, and an arrow UP indicating the upper side of the vehicle are shown.

FIG. 1 is a diagram showing a left side surface of a motorcycle 1 on which a power unit PU employing an engine E according to this embodiment is mounted.
In FIG. 1, Wf and Wr are a front wheel supported by a body frame (not shown) via a front fork 2 and a rear wheel supported by a body frame via a swing arm 3. Further, H is a steering handle disposed above the front fork 2, S is a seat on which an occupant is seated, and T is a fuel tank disposed in front of the seat S. The power unit PU is mounted below the fuel tank T in the center of the body frame.
The power unit PU shifts the drive rotation of the engine E by the transmission M, and transmits the output to the rear wheel Wr via the transmission mechanism. In the following description of the power unit PU, the directions such as front, rear, left and right are the same as those when mounted on a vehicle unless otherwise specified.

FIG. 2 is a right side view of the power unit PU, and FIG. 3 is a view showing a left side surface of the power unit PU. FIG. 4 is a diagram showing an upper surface of the power unit PU. FIG. 5 is a cross-sectional view substantially corresponding to the VV cross section of FIG. 2 in the power unit PU. FIG. 6 is a cross-sectional view substantially corresponding to the VI-VI cross section of FIG. 2 in the power unit PU.

The engine E of the power unit PU includes a crankcase 11 that rotatably supports the crankshaft 10 and a cylinder portion 12 that protrudes obliquely upward from the front upper portion of the crankcase 11. The crankcase 11 also serves as a transmission case of the transmission M. The crankshaft 10 is disposed on the front side, and the main shaft 13 (transmission shaft) and the counter shaft of the transmission M are disposed on the rear side of the crankshaft 10. 14 is arranged in parallel with the crankshaft 10. The main shaft 13 and the counter shaft 14 are rotatably supported by the crankcase 11. As shown in FIG. 5, the counter shaft 14 penetrates the left side wall of the crankcase 11 to the outside, and a sprocket 15 for taking out power is attached to the end of the countershaft 14. A chain 9 is hung around the sprocket 15, and power is transmitted to the rear wheel through the chain 9.
In this embodiment, the counter shaft 14 and the sprocket 15 constitute a power take-out unit in the power unit PU.

The cylinder part 12 includes a cylinder block 17, a cylinder head 18, and a head cover 19.
The cylinder block 17 has a cylinder bore 17a that accommodates the piston 16 so as to be able to advance and retract. The cylinder head 18 is attached to the upper part of the cylinder block 17 and forms the combustion chamber 7 with the top surface of the piston 16. The head cover 19 is attached to the upper part of the cylinder head 18.
As shown in FIG. 6, the cylinder head 18 is overlaid on the upper portion of the cylinder block 17 and is fastened together with the cylinder block 17 to the upper surface of the crankcase 11 by a plurality of (four) stud bolts 20 (fastening members). .

The piston 16 is connected to the crankshaft 10 through a connecting rod 23 so as to be interlocked with the piston 16 and transmits the forward / backward movement of the piston 16 accompanying the explosion in the combustion chamber 7 to the crankshaft 10 as a rotational force. Note that reference numeral 8 in FIG. 5 is a spark plug provided facing the combustion chamber 7.

The cylinder head 18 is formed with an intake port and an exhaust port (not shown) and an intake valve and an exhaust valve (not shown) that open and close the intake port and the exhaust port. As shown in FIGS. 2 and 3, an inlet pipe 6 constituting an intake system of the engine E is connected to the intake port. An exhaust pipe (not shown) constituting an exhaust system of the engine E is connected to the exhaust port. Further, as shown in FIG. 6, a valve operating mechanism 21 that opens and closes the intake valve and the exhaust valve is provided between the cylinder head 18 and the head cover 19. Reference numeral 22 in FIG. 6 is a cam shaft for operating a valve cam of the valve mechanism 21. The camshaft 22 is connected to the crankshaft 10 via the timing chain 5 so as to be interlocked.

The engine E of this embodiment is a water-cooled single-cylinder engine. The cylinder block 17 is provided with a single cylinder bore 17a, and a water jacket 50 is formed around the cylinder bore 17a. Reference numeral 51 in FIGS. 2, 4, and 5 is a water pump for supplying cooling water cooled by a radiator (not shown) to the water jacket 50.

As shown in FIGS. 5 and 6, the crankcase 11 includes a pair of case halves 11 L and 11 R that are divided on the left and right sides with dividing surfaces 11 La and 11 Ra orthogonal to the crankshaft 10. The left and right case halves 11L and 11R are divided into left and right in a plane passing through the cylinder center axis C1 of the cylinder block 17, and the divided case halves 11L and 11R are fastened and fixed by a plurality of bolts (not shown). A crank cover 30 that forms a sealed space with the case half 11R is attached to the right side of the right case half 11R.

As shown in FIG. 5, the right end portion of the crankshaft 10 penetrates the side wall of the right case half 11 R, and the penetrated end portion transmits power to the main shaft 13 of the transmission M. A primary drive gear 24 is attached. The left end portion of the crankshaft 10 penetrates the side wall of the left case half 11L, and the rotor 25a of the generator 25 is attached to the penetrated end portion. The end portion and the peripheral region of the rotor 25a are covered with a cover 25c of the generator 25 that holds the stator 25b.

Further, the right end of the main shaft 13 of the transmission M penetrates the side wall of the right case half 11R. A primary driven gear 26 that meshes with the primary drive gear 24 on the crankshaft 10 side and a clutch 27 that connects and disconnects power by an external operation are supported at the end of the main shaft 13 that passes through the right case half 11R. Has been. The primary driven gear 26 is rotatably supported by the main shaft 13, and the clutch 27 is interposed in a power transmission path between the primary driven gear 26 and the main shaft 13. Therefore, the clutch 27 can appropriately switch between transmission and interruption of power between the primary driven gear 26 and the main shaft 13 by an operation from the outside.

The main shaft 13 and the counter shaft 14 of the transmission M are provided with a main gear group m1 and a counter gear group m2 composed of a plurality of transmission gears. The transmission M selects transmission gears of the main gear group m1 and the counter gear group m2 by operating a change mechanism (not shown), thereby setting an arbitrary transmission gear stage (gear position) including neutral. Therefore, when the transmission power of the crankshaft 10 is transmitted to the main shaft 13 via the clutch 27 in the state where the transmission gear stage is set in this way, the transmission M changes the rotational power to the set ratio and counters it. Output from the shaft 14 to the outside.
Note that reference numeral 28 in FIG. 5 denotes a kick shaft for rotating the crank shaft 10 at the time of kick start.

2 to 4, a balancer shaft 29 extending in parallel with the crankshaft 10 is disposed at an upper position between the crankshaft 10 and the main shaft 13 in the crankcase 11. The balancer shaft 29 is rotatably supported by the crankcase 11. The balancer shaft 29 rotates synchronously with the crankshaft 10 via a gear (not shown), thereby canceling the rotational fluctuation of the crankshaft 10 and maintaining the rotation balance.

Also, as shown in FIG. 6, an oil pan 31 is provided at the bottom of the crankcase 11 to store lubricating oil. An oil pump 32 (oil supply source) is installed above the oil pan 31 of the right case half 11R to pump up the oil in the oil pan 31 and pump the oil to a portion in the power unit PU that requires lubrication. Has been. The oil pump 32 of this embodiment is operated by receiving rotational power from the crankshaft 10.

The oil supply path 33 in the power unit PU connected to the oil pump 32 passes oil from the discharge part of the oil pump 32 through the crankshaft 10 to the part that needs lubrication around the crankshaft 10 such as a crankpin and a journal part. Is divided into a crank system oil path 33C for supplying oil and a valve system oil path 33B for supplying oil from the upper part of the crankcase 11 through the inside of the cylinder portion 12 to a portion where lubrication of the valve mechanism 21 is required. ing. A branch oil passage 34 for supplying oil around shafts such as the main shaft 13 and the counter shaft 14 of the transmission M is connected in the middle of the valve operating oil passage 33B.

FIG. 7 is a bottom view of the cylinder block 17 corresponding to the view taken along the arrow VII in FIG. FIG. 8 is a perspective view of the crankcase 11 and the cylinder block 17 with the section VIII-VIII in FIG. FIG. 9 is a perspective view of the case half 11R on the right side of the crankcase 11 as viewed from the obliquely upward rear side so that the dividing surface 11Ra is substantially directed to the front. FIG. 10 is a perspective view of the case half 11L on the left side of the crankcase 11 as viewed from the front obliquely upward side so that the dividing surface 11La is substantially directed to the front.

A part of the valve operating oil passage 33B of the oil supply passage 33 is between the upper end surfaces 11Ru, 11Lu (joint surface) of the crankcase 11 and the lower surface 17d (joint surface) of the cylinder block 17, as shown in FIG. Is formed. As shown in FIG. 6, the oil passage between the joint surface of the crankcase 11 and the cylinder block 17 has an oil inflow portion 35 a connected to the oil pump 32 in the vicinity of the front right corner of the cylinder block 17. An oil outflow portion 36 a that is provided and connected to the valve operating mechanism 21 side is provided at the corner on the left side of the rear portion of the cylinder block 17. The inflow portion 35a and the outflow portion 36a of the oil passage between the joint surfaces are arranged in a range overlapping on a diagonal line L1 passing through the cylinder center axis C1, as shown in FIG.

The oil passage between the joint surface of the crankcase 11 and the cylinder block 17 is a first oil passage 35 formed between the end surface 11Ru of the right (one) case half 11R and the lower surface 17d of the cylinder block 17. And a second oil passage 36 formed between the end surface 11Lu of the left (other) case half body 11L and the lower surface 17d of the cylinder block 17.

In the case of this embodiment, the first oil passage 35 includes a flat end surface 11Ru of the right case half 11R, and a groove 35c formed in the lower surface 17d of the cylinder block 17 substantially along the outer peripheral edge of the cylinder bore 17a. It is surrounded by. An inflow portion 35 a connected to the oil pump 32 side is provided at one end of the first oil passage 35 in the extending direction.
The second oil passage 36 is formed by being surrounded by a flat end surface 11Lu of the left case half 11L and a groove 36c formed in the lower surface 17d of the cylinder block 17 substantially along the outer peripheral edge of the cylinder bore 17a. ing. At one end in the extending direction of the second oil passage 36, an outflow portion 36a connected to the valve operating mechanism 21 side is provided.
In FIG. 6, the cross section is adjusted so that the first oil passage 35 and the second oil passage 36 appear on the drawing.

The first oil passage 35 extends in an arc shape from the inflow portion 35a on the front right side of the cylinder block 17 through the rear right side of the cylinder block 17 to the vicinity of the center of the rear portion. As shown in FIGS. 6 and 9, one end of a first bypass hole 37 formed in the right case half 11 R is electrically connected to the other end of the first oil passage 35.

Further, the second oil passage 36 extends in an arc from the outflow portion 36a on the left side of the rear portion of the cylinder block 17 to the vicinity of the center of the rear portion of the cylinder block 17, and ends in the vicinity of the center of the rear portion. As shown in FIGS. 6 and 8, one end of a second bypass hole 38 formed in the left case half 11 L is electrically connected to the other end of the second oil passage 36.

The first bypass hole 37 is configured by a substantially L-shaped hole having one end opened to the upper end surface 11Ru of the right case half 11R. The other end 37a of the first bypass hole 37 opens at a position apart from the upper end surface 11Ru in the dividing surface 11Ra of the right case half 11R.

The second bypass hole 38 is configured by a substantially L-shaped hole having one end opened to the upper end surface 11Lu of the left case half 11L. The other end 38a of the second bypass hole 38 opens at a position apart from the upper end surface 11Lu of the dividing surface 11La of the left case half 11L. The other end of the first bypass hole 37 and the other end of the second bypass hole 38 are joined to each other by joining the left and right case halves 11L and 11R to each other. Yes.

Therefore, the first oil passage 35 and the second oil passage 36 are connected to each other via the first bypass hole 37 and the second bypass hole 38. Thereby, the oil flowing into the inflow portion 35a from the oil pump 32 sequentially passes through the first oil passage 35, the first bypass hole 37, the second bypass hole 38, the second oil passage 36, and the outflow portion 36a. Supplied to the valve mechanism 21 of the section 12.

Further, the second bypass hole 38 has a vertical hole portion that extends downward from the upper end surface 11Lu of the case half body 11L, and further downwards beyond a horizontal hole portion connected to the first bypass hole 37 side. It has been extended by a predetermined length.
A branch oil passage 34 for supplying oil around shafts such as the main shaft 13 and the counter shaft 14 of the transmission M is connected to a side surface of the extension 40 that is separated from the bottom 40a.

Incidentally, as shown in FIG. 7, the cylinder block 17 is formed with insertion holes 39 through which the stud bolts 20 are inserted at the four corners of the peripheral portion surrounding the cylinder bore 17a. The four insertion holes 39 are arranged on the same pitch circle P around the cylinder center axis C1. A part of each of the inflow portion 35a of the first oil passage 35 and the outflow portion 36a of the second oil passage 36 is a region outside the pitch circle P and close to the insertion hole 39. Is arranged. Moreover, the inflow part 35a and the outflow part 36a are arrange | positioned in the range which overlaps on the diagonal L1 which passes along the cylinder central axis C1 as mentioned above. Therefore, the first oil passage 35 and the second oil passage 36 are formed over the cylinder bore 17a over the length of about a half circumference across the position of the split surfaces 11La and 11Ra of the crankcase 11. .

A part of the branch oil passage 34 branched from the second bypass hole 38 includes an orifice hole 41 connected to the extension 40, a passage groove 49 formed along the dividing surface 11La of the left case half 11L, Have The passage groove 49 is abutted against the flat dividing surface 11Ra of the right case half body 11R by fastening the left and right

case half bodies

11L and 11R, thereby part of the passage toward the transmission M direction. Is configured.

The orifice hole 41 is formed on the split surface 11La side of the left case half 11L so as to communicate with the side surface of the extension 40 from the bottom of the passage groove 49 by drilling or the like.

As shown in FIG. 10, the passage groove 49 extends in an arc shape toward the lower rear part in a region surrounding the outer side of the balancer shaft 29 of the peripheral wall of the left case half 11 L. The rear lower end of the passage groove 49 has a left passage hole 42 (transverse hole) and a right passage hole formed in a straight line in the left-right direction in the left case half 11L and the right case half 11R. 43 (see FIG. 11). The left passage hole 42 constitutes a part of a passage for supplying oil to a portion around the main shaft 13 of the transmission M that requires lubrication. Further, the right passage hole 43 constitutes a part of a passage for supplying oil to a portion around the counter shaft 14 of the transmission M that requires lubrication.

Further, as shown in FIG. 10, the region facing the dividing surface 11La of the peripheral wall of the left case half 11 L extends from the outer region of the second bypass hole 38 and the passage groove 49 to the rear side of the left passage hole 42. A catching groove 44 extending in the direction is formed. The extending end of the catching groove 44 extending around the rear side of the left passage hole 42 opens into the inner space of the crankcase 11. The capture groove 44 captures and captures oil when the oil flowing through the passage groove 49 and the second bypass hole 38 leaks outside the passage groove 49 and the second bypass hole 38 along the dividing surfaces 11La and 11Ra. It functions to return the returned oil into the crankcase 11.

FIG. 11 is a plan view centering directly on the main shaft 13 of the transmission M of the power unit PU. FIG. 12 is a perspective view of the power unit PU as viewed from above the left front part, with a section corresponding to the XII-XII section of FIG. FIG. 13 is a perspective view of the power unit PU as viewed from the left rear upper side. FIG. 14 is a cross-sectional view corresponding to the XIV-XIV cross section of FIG. 15 is a cross-sectional view corresponding to the XV-XV cross section of FIG.
As shown in FIG. 11, the rotation of the rotating element on the main shaft 13 of the transmission M is detected in a portion of the upper wall 11Le of the left case half 11L adjacent to the rear portion of the left passage hole 42. A rotation sensor 53 is attached. The rotation sensor 53 detects the rotation of the detection target gear near the left end in the axial direction on the main shaft 13. As shown in FIGS. 12 to 14, a sensor attachment hole 54 penetrating the upper wall 11Le is formed in the upper wall 11Le near the left end of the case half 11L. The rotation sensor 53 is attached to the sensor attachment hole 54, and the detection portion 53 a on the front end side is close to the tooth surface of the detection target gear on the main shaft 13 in the crankcase 11. In the case of this embodiment, the axis C2 of the sensor mounting hole 54 is formed to be inclined slightly forward toward the lower side as shown in FIG. For this reason, the detection part 53a of the rotation sensor 53 is directed in the direction of the main shaft 13 in a state where it is slightly inclined forward.

On the upper wall 11Le of the left case half 11L, a transverse bead 55 that crosses the vicinity of the front side of the sensor mounting hole 54 in a direction parallel to the main shaft 13 as viewed from the direction along the axis C2 of the sensor mounting hole 54 is outward. It is formed to bulge out. The transverse bead 55 bulges upward and to the left with respect to the upper wall 11Le near the left end of the case half 11L. In addition, a bent bead 56 that extends from the outer end of the transverse bead 55 toward the vicinity of the left end in the axial direction of the main shaft 13 bulges to the left on the left end wall of the case half 11L. Is formed.

In the transverse bead 55, the left passage hole 42 (transverse hole) that forms part of the oil supply passage 33 is formed. A bent hole 57 whose upper end portion is electrically connected to the left passage hole 42 is formed in the bent bead 56. The lower end of the bent hole 57 is electrically connected to the left end portion of the main shaft 13 in the axial direction, and the oil introduced through the left passage hole 42 and the bent hole 57 is lubricated around the main shaft 13 through the passage in the main shaft 13. Is supplied to the necessary parts.

As shown in FIGS. 14 and 15, the transverse bead 55 and the left passage hole 42 inside thereof extend in the left-right direction between the balancer shaft 29 and the rotation sensor 53. Further, the bending bead 56 and the bending hole 57 inside thereof are inclined rearward from the upper end portion toward the lower end portion at the left end side position with respect to the sensor mounting hole 54. The bent bead 56 is formed so as to partially overlap the detection portion 53a on the distal end side of the rotation sensor 53 in a side view as viewed from the direction along the main shaft 13. Therefore, the bent bead 56 covers a part of the left side portion of the rotation sensor 53 at the left end portion of the left case half 11L.
Also, as shown in FIGS. 12 and 14, the wall thickness T1 of the upper wall of the left passage hole 42 of the transverse bead 55 is the wall of the other region around the sensor mounting hole 54 of the left case half 11L. It is formed thicker than.

Further, the left end portion of the counter shaft 14 of the transmission M protrudes laterally from the side wall of the left case half 11L, and the discharged portion is covered with the cover wall 58. The cover wall 58 has an arcuate flange 58a that protrudes from the left end side of the case half 11L. The flange portion 58a covers the protruding portion of the counter shaft 14 and the peripheral area of the substantially front half of the sprocket 15 (see FIG. 5), and protects them from the outside. The flange portion 58a is formed so as to surround the lower rear side of the detection portion 53a of the rotation sensor 53.

Further, as shown in FIG. 15, a part of the flange portion 58 a extends from the upper side of the counter shaft 14 across the left side of the detection portion 53 a of the rotation sensor 53 toward the diagonally lower front side.
For this reason, the collar part 58a and the bending bead 56 are formed so that both form V shape in the side view seen from the direction along the main axis | shaft 13. As shown in FIG. The rotation sensor 53 is disposed so as to be sandwiched between V-shaped shapes formed by the flange portion 58 a and the bent bead 56 when viewed from the side along the direction along the main shaft 13.

Further, as shown in FIG. 14, the portion of the upper wall 11Le of the left case half 11L where the sensor mounting hole 54 is formed is convex toward the inside of the crankcase 11 (downward). An orientation convex portion 59 is formed. The sensor mounting hole 54 is formed from the upper surface of the upper wall 11Le to the top of the inward convex portion 59, and the lower end of the sensor mounting hole 54 opens at the top of the inward convex portion 59. Therefore, the sensor mounting hole 54 surrounding the rotation sensor 53 has a sufficiently long axial length.

Next, the flow of oil in each part of the unit in the power unit PU according to this embodiment will be described.
When the crankshaft 10 is rotated by driving the engine E, the oil pump 32 is activated by receiving the rotation of the crankshaft 10. As shown in FIG. 6, the oil pump 32 sucks up the oil stored in the oil pan 31 and discharges the oil to the oil supply path 33 side. The oil discharged from the oil pump 32 branches into a crank system oil path 33C and a valve system oil path 33B in the upper part of the case half 11R on the right side of the crankcase 11. The oil flowing into the crank system oil passage 33C passes through the passage in the crankshaft 10 from the right end portion of the crankshaft 10, and is supplied to a portion requiring lubrication around the crankshaft 10, such as a crankpin and a journal portion. .

On the other hand, the oil flowing into the valve operating oil passage 33B passes through a passage extending upward from the front right side of the right case half body 11R, and as shown in FIGS. 6 and 7, the upper side of the right case half body 11R. Flows into the first oil passage 35 formed between the end face 11Ru and the lower surface 17d of the cylinder block 17 through the inflow portion 35a.

The oil that has flowed into the first oil passage 35 flows in an arc shape around the cylinder bore 17a along the first oil passage 35 toward the center of the rear portion, and below the portion immediately before the dividing surface 11Ra of the right case half 11R. The direction is changed to flow into the first bypass hole 37 of the case half 11R.

The oil that has flowed into the first bypass hole 37 changes its direction at the lower end in a substantially L shape in the direction of the dividing surface 11La, and a coupling portion between the dividing surfaces 11Ra and 11La of the right case half body 11R and the left case half body 11L. Flows into the second bypass hole 38 of the left case half 11L. A part of the oil flowing into the second bypass hole 38 is formed between the upper end surface 11Lu of the left case half 11L and the lower surface 17d of the cylinder block 17 by changing the direction upward in a substantially L shape. Into the second oil passage 36. The remaining oil that has flowed into the second bypass hole 38 changes its direction downward and flows into the extension 40, and enters the branch oil passage 34 on the transmission M side through the orifice hole 41 provided on the side surface of the extension 40. Flows in.

The oil flowing into the second oil passage 36 from the second bypass hole 38 flows from the rear center side of the cylinder block 17 around the cylinder bore 17a toward the outflow portion 36a near the rear left corner, and from the outflow portion 36a to the cylinder block. The valve mechanism 21 is supplied to a portion requiring lubrication through a passage in the valve 17.

The oil that has flowed into the orifice hole 41 from the second bypass hole 38 through the extension 40 passes through the passage groove 49 formed in the dividing surface 11La of the left case half 11L, as shown in FIGS. The flow then branches into the left passage hole 42 and the right passage hole 43 on the rear side of the balancer shaft 29.
The oil that has flowed into the left passage hole 42 flows into the bent hole 57 in the left end region in the axial direction of the left case half 11L, and changes its direction rearward and obliquely downward to the left end of the main shaft 13 of the transmission M. From the main shaft 13 through a passage in the main shaft 13 and supplied to a portion requiring lubrication around the main shaft 13 such as a bearing portion and a transmission gear. On the other hand, the oil that has flowed into the right passage hole 43 turns rearward in the right end region in the axial direction of the right case half 11R, and enters the counter shaft 14 from the right end portion of the counter shaft 14 of the transmission M. The portion around the counter shaft 14 is supplied to a portion requiring lubrication through the passage.

As described above, in the power unit PU according to this embodiment, the first oil passage 35 formed between the cylinder block 17 and the right case half 11R, and the cylinder block 17 and the left case half 11L. And the second oil passage 36 formed between the first and second case halves 11R and 11L are connected to each other at the divided surfaces 11Ra and 11La separated from the upper end surfaces 11Ru and 11Lu (joint surfaces). The first bypass hole 37 and the second bypass hole 38 are connected. For this reason, the oil supply path 33 formed between the cylinder block 17 and the crankcase 11 is not connected across the joint of the three members.
Therefore, by adopting the structure of the power unit PU, the joint between the cylinder block 17 and the left and right case halves 11L and 11R can be obtained without requiring extremely high processing accuracy and sealing performance for preventing oil leakage. The straddling oil supply path 33 can be easily formed. Therefore, the degree of freedom in designing the oil supply path 33 can be increased by adopting the structure of the power unit PU.

Further, in the power unit PU of this embodiment, as shown in FIG. 7, the cylinder block 17 and the case half are placed so that the inflow portion 35a and the outflow portion 36a overlap with a diagonal line L1 passing through the cylinder central axis C1 of the cylinder block 17. A first oil passage 35 and a second oil passage 36 are formed between the joint surfaces of 11R and 11L. In the case of this power unit PU, the inflow portion 35a and the outflow portion 36a are disposed in a diagonal position relationship farthest around the cylinder center axis C1. However, since the first oil passage 35 and the second oil passage 36 are connected via the first bypass hole 37 and the second bypass hole 38 that are abutted with each other at the dividing surfaces 11Ra and 11La, the oil supply path While arranging 33 with a high degree of freedom, it is possible to easily prevent oil leakage from the oil supply path 33.

Furthermore, in the case of the power unit PU of this embodiment, a part of the inflow portion 35 a of the first oil passage 35 and the outflow portion 36 a of the second oil passage 36 are inserted through the stud bolt 20 formed in the cylinder block 17. The inflow portion 35 a and the outflow portion 36 a are both disposed in the vicinity of the insertion hole 39 through which the stud bolt 20 is inserted. For this reason, when the cylinder block 17 is fastened and fixed to the crankcase 11 by the stud bolt 20, the vicinity of the inflow portion 35 a and the outflow portion 36 a can be firmly adhered by tightening with the stud bolt 20.
Therefore, by adopting this structure, even if the inflow portion 35a and the outflow portion are disposed radially outside the pitch circle P, oil leakage from the vicinity of the inflow portion 35a and the outflow portion 36a is prevented. be able to.

In the power unit PU according to this embodiment, the first bypass hole 37 and the second bypass hole 38 connecting the first oil passage 35 and the second oil passage 36 are branched from the second bypass hole 38. A branch oil passage 34 for supplying oil to the transmission M side is provided. For this reason, a passage and a passage which supply oil to the cylinder block 17 side can be partially used. Therefore, by adopting this structure, the oil passage of the entire power unit PU can be simplified.
In this embodiment, the branch oil passage 34 is provided in the second bypass hole 38 of the left case half 11L. However, the branch oil passage 34 is provided in the first bypass hole 37 of the right case half 11R. You may make it provide in. The branch oil passage 34 may be provided so as to communicate with both the first bypass hole 37 and the second bypass hole 38.

In particular, in the power unit PU according to this embodiment, the branch oil passage 34 is provided by branching from the side surface of the extension 40 extending downward from the lower end of the second bypass hole 38. For this reason, the foreign matter mixed in the oil can be deposited on the bottom 40 a of the extension 40 before being sent to the branch oil passage 34. Therefore, by adopting this structure, foreign matters can be removed from the oil supplied to the transmission M side.
When the branch oil passage 34 is provided in the first bypass hole 37 of the right case half 11 R, the extension 40 may be provided in the first bypass hole 37 in the same manner.

Further, in the case of the power unit PU according to this embodiment, a part of the branch oil passage 34 is constituted by a passage groove 49 formed facing the dividing surfaces 11La and 11Ra of the case halves 11L and 11R. The passage groove 49 can be easily formed on the dividing surface 11La of one case half 11L by cutting or the like, even if the passage shape is somewhat complicated. For this reason, a part of the branch oil passage 34 can be easily formed by adopting this structure.

Furthermore, in this embodiment, a catching groove 44 that catches oil leaking outside the passage groove 49 and returns it to the crankcase 11 is formed in the outer region of the passage groove 49 in the outer wall of the case half 11L. Has been. Therefore, even if the oil flowing through the passage groove 49 leaks outside the passage groove 49 through the space between the split surfaces 11La and 11Ra of the case halves 11L and 11R, the leaked oil is captured by the catching groove 44. It is possible to efficiently capture and prevent oil from leaking out of the crankcase 11.
When the branch oil passage 34 is provided in the first bypass hole 37, the passage groove 49 and the catching groove 44 may be formed on the dividing surface 11Ra of the right case half 11R.

Further, in the case of the power unit PU of this embodiment, the orifice portion arranged on the upstream side of the passage groove 49 of the branch oil passage 34 is constituted by the orifice hole 41 formed at the bottom portion of the passage groove 49. . Therefore, the orifice hole 41 can be easily formed in the bottom of the passage groove 49 of the case half body 11L by drilling or the like, and the number of parts can be increased compared to the case where the orifice part is configured by incorporating the orifice part. Reduction can be achieved.

In addition, this invention is not limited to said embodiment, A various design change is possible in the range which does not deviate from the summary. For example, in the above embodiment,

grooves

35c and 36c are formed on the end faces 11Lu and 11Ru of the case halves 11L and 11R, and the first oil is provided between the cylinder block 17 and the case halves 11L and 11R. A passage 35 and a second oil passage 36 are formed. However, the end surfaces 11Lu and 11Ru of the case halves 11L and 11R are flat surfaces, and a groove is formed on the lower surface 17d side of the cylinder block 17 so that the first half between the cylinder block 17 and the case halves 11L and 11R is formed. The oil passage 35 and the second oil passage 36 may be configured.
The vehicle on which the power unit is mounted may be not only a motorcycle but also a three-wheeled vehicle (including a front two-wheeled vehicle and a rear two-wheeled vehicle in addition to a front one wheel and a rear two-wheeled vehicle) or a four-wheeled vehicle.

DESCRIPTION OF SYMBOLS 10 ... Crankshaft 11 ...

Crankcase

11L, 11R ... Half case 11La, 11Ra ... Dividing surface 11Lu, 11Ru ... End surface (joint surface)
16 ... Piston 17 ... Cylinder block 17d ... Lower surface (joint surface)
20 ... Stud bolt (fastening member)
32 ... Oil pump (oil supply source)
33 ... Oil supply passage 34 ... Branch oil passage 35 ... First oil passage 35a ... Inflow portion 36 ... Second oil passage 36a ... Outflow portion 37 ... First bypass hole 38 ... Second bypass hole 39 ... Insertion hole 40 ... Extension part 41 ... Orifice hole 44 ... Capture groove 49 ... Passage groove C1 ... Cylinder center axis L1 ... Diagonal line M ... Transmission

Claims

A crankcase that rotatably supports the crankshaft, and is formed by mutually joining a pair of case halves divided by a dividing surface that intersects the crankshaft;
A cylinder block that accommodates a reciprocating piston and is joined across an end surface that intersects the split surface of each case half of the crankcase;
An oil supply path that is formed from the crankcase to the cylinder block and that supplies oil supplied from an oil supply source on the crankcase side to a portion in the engine that needs lubrication, and
The oil supply path is
A first oil passage formed between joint surfaces of the cylinder block and one case half of the crankcase; and an inflow portion into which oil from the oil supply source flows.
A second oil passage formed between a joint surface between the cylinder block and the other case half of the crankcase;
One case half is connected to the first oil passage and the other end is connected to a portion of the one half of the split surface that is separated from the joint surface with the cylinder block. A first bypass hole formed;
One end is connected to the second oil passage and the other end is connected to the second case half so that the other case half is connected to a portion of the other case half separated from the joint surface with the cylinder block. A second bypass hole formed,
The lubrication structure for an engine, wherein the other end of the first bypass hole and the other end of the second bypass hole are connected to each other on the divided surface.
2. The engine according to claim 1, wherein the first oil passage and the second oil passage are formed such that the inflow portion and the outflow portion overlap a diagonal line passing through a cylinder central axis of the cylinder block. Lubrication structure.
The cylinder block is fastened and fixed to the crankcase by a plurality of fastening members,
The insertion holes of the fastening member formed in the cylinder block are arranged on the same pitch circle centered on the cylinder central axis,
The engine lubrication structure according to claim 2, wherein at least a part of each of the inflow portion and the outflow portion is disposed in a region radially outward from the pitch circle and in the vicinity of the insertion hole.
The crankcase is integrally provided with a transmission housing portion for housing the transmission, and supplies oil to the transmission by branching from at least one of the first bypass hole and the second bypass hole. The engine lubricating structure according to any one of claims 1 to 3, wherein a branch oil passage is formed.
5. The engine lubrication structure according to claim 4, wherein the branch oil passage is branched from a side surface of an extension portion that extends downward from a lower end of at least one of the first bypass hole and the second bypass hole.
6. The engine lubrication structure according to claim 4, wherein a part of the branch oil passage is configured by a passage groove formed in at least one of the pair of case halves so as to face the dividing surface.
The catch groove | channel which catches the oil which leaked to the outer side of the said channel groove, and returns it in the said crank case in the outer region of the said channel groove of the outer walls of the said crankcase is provided. Engine lubrication structure.
An orifice is provided on the upstream side of the passage groove of the branch oil passage,
The engine lubrication structure according to claim 6 or 7, wherein the orifice portion is configured by an orifice hole formed in a bottom portion of the passage groove.