JP5122434B2 - Cam chain tensioner device for internal combustion engine - Google Patents

Description

  The present invention relates to a tensioner device that applies a required tension to a cam chain that transmits rotation of a crankshaft in an internal combustion engine to a valve train.

  An endless cam chain spanned between a drive sprocket fitted to a crankshaft rotatably supported by a crankcase and a driven sprocket fitted to a camshaft of a valve train is a cam chain It is pressed from the side by the tensioner device, and is maintained at a constant tension without loosening.

In a hydraulic cam chain tensioner device, a push rod pressed against a pressing member that presses the cam chain is inserted into a guide cylinder so as to be able to advance and retreat, and an oil chamber is formed therein, allowing oil to flow into the oil chamber. On the other hand, a control valve for preventing the oil from flowing out from the oil chamber is provided, and a compression spring for biasing the push rod in the protruding direction is interposed in the oil chamber.
That is, the push rod of the hydraulic cam chain tensioner device moves forward but does not move backward.

  Therefore, when the cam chain stretches due to secular change, etc., the push rod advances by the urging force of the compression spring and presses the cam chain via the pressing member, giving a predetermined tension without loosening, and control at that time When the valve flows into the oil chamber and receives a reaction force from the cam chain, the control valve prevents the oil from flowing out and locks it to prevent the push rod from moving backward, maintaining the cam chain at a constant tension. To do.

  There is an example in which a dedicated oil passage is provided to guide the oil to the oil chamber of such a hydraulic cam chain tensioner device, but the structure is complicated and the processing is cumbersome and the manufacturing cost is high, so the push rod is inserted. There is an example in which an oil reservoir is formed at the upper end opening portion of the guide cylinder so that oil enters the oil chamber in the guide cylinder from the oil reservoir (see, for example, Patent Document 1).

Japanese Patent No. 4035226

In Patent Document 1, an oil separator separate from the crankcase is fastened to the bottom wall of the cam chain chamber of the crankcase.
The oil separator is integrally formed with an oil reservoir that opens upward and a guide cylinder into which the push rod is inserted.

Since the oil reservoir and the guide cylinder are integrally formed, the oil separator has a complicated shape, is not easy to manufacture, and the crankcase side must also have a space for storing the oil separator, Manufacturing man-hours are large and manufacturing costs are high.
The oil separator is a separate part from the crankcase, and there are many parts including a fastening member for fastening the oil separator to the crankcase, resulting in a complicated structure and an increase in cost.

  The present invention has been made in view of the above points, and an object thereof is to provide a cam chain tensioner device having a small number of parts, a simple structure, and a low cost.

In order to achieve the above object, a first aspect of the present invention provides a drive sprocket (12) fitted to a crankshaft (10) rotatably supported by a crankcase (2) of an internal combustion engine, and a valve operating valve. Pressing member (31, 33) that presses against an endless cam chain (23) spanned in a cam chain chamber (2C) between a driven sprocket (12) fitted to the cam shaft (22) of the system ), A push rod (36) slidably inserted into the guide hole (37) and press-contacting the pressing member (31, 33), and the push rod (36) inside the guide hole (37). An oil chamber (37a) formed by being covered with a lid portion (45s), and provided on the lid portion (45s) of the push rod (36) while allowing the oil to flow into the oil chamber (37a) A control valve (45) for preventing oil from flowing out from the oil chamber (37a), and a compression spring (47) interposed in the oil chamber (37a) and biasing the push rod (36) in the protruding direction With and before In the cam chain tensioner device for an internal combustion engine that constantly applies a predetermined tension to the cam chain (23), the guide hole (37) is formed to open at least upward in the lower part of the crankcase (2L), and downward.凹出to the cam chain chamber upper opening of the guide hole a recess which is open upward to (2C) (37) of the oil reservoir facing the interior (40) is formed integrally with the crankcase (2L), the The oil guide rib (50) protruding from the wall surface on the cam chain chamber (2C) side of the bearing wall (2Lw) of the crankshaft (10) of the crankcase (2L) is inclined below the drive sprocket (10). The cam chain tensioner device for the internal combustion engine is formed and the oil reservoir (40) is located below the lower end of the oil guide rib (50) .

  According to a second aspect of the present invention, in the cam chain tensioner device for an internal combustion engine according to the first aspect, the upper opening facing the inside of the oil sump of the guide hole has a front and rear guide wall constituting the upper portion of the guide hole. It extends inside the oil sump and is formed to open upward and to the left and right sides by the front and rear guide walls. The push rod is inserted into the guide hole, and is supported by the front and rear guide walls so as to be slidable. The left and right openings between the front and rear guide walls communicate with the oil sump.

According to a third aspect of the present invention, in the cam chain tensioner device for an internal combustion engine according to the first or second aspect, two oil reservoirs are arranged in the longitudinal direction of the vehicle body to form a front oil reservoir and a rear oil reservoir. The front oil sump and the rear oil sump are in communication with each other.

According to a fourth aspect of the present invention, in the cam chain tensioner device for an internal combustion engine according to the third aspect , the front oil sump is located below the lower end of the oil guide rib, and the front wall of the front oil sump projects forward, The bottom surface of the front oil sump and the bottom surface of the rear oil sump are continuous while being inclined obliquely downward toward the rear, and the upper opening of the guide hole faces the rear oil sump. .

According to a fifth aspect of the present invention, in the cam chain tensioner device for an internal combustion engine according to the fourth aspect , the crankcase has an oil return passage formed below a front wall protruding forward of the front oil sump. Features.

According to a sixth aspect of the present invention, in the cam chain tensioner device for an internal combustion engine according to any one of the first to fifth aspects, one side wall of the oil sump formed in the crankcase in the vehicle body width direction is It is characterized by being constituted by abutment of a separate side wall plate.

According to a seventh aspect of the present invention, in the cam chain tensioner device for an internal combustion engine according to any one of the first to sixth aspects, the guide hole opens in a side wall of the crankcase and is closed by a tensioner bolt. The lower end is formed to be inclined so as to be positioned in front of the vehicle body from the upper end, and the drain bolt for closing the drain bolt hole formed in the bottom wall of the crankcase is provided below the tensioner bolt in a side view of the vehicle body. Features.

The invention according to claim 8 is the cam chain tensioner device for an internal combustion engine according to any one of claims 1 to 7, wherein the crankcase (2L) is provided with the oil sump (40). A mission chamber (3S) is formed by a partition wall (2Lw) behind the cam chain chamber (2C) in the longitudinal direction of the vehicle body, and communicates with an obliquely upper portion of the oil reservoir (40) in the partition wall (2Lw). characterized in that the mouth (52) is formed.

According to a ninth aspect of the present invention, in the cam chain tensioner device for an internal combustion engine according to any one of the first to eighth aspects, the internal combustion engine is mounted on a vehicle with a crankshaft oriented in a vehicle body width direction. A cell motor and an intermediate gear are disposed below the front side of the crankcase that supports the crankshaft.

A tenth aspect of the present invention is the cam chain tensioner device for an internal combustion engine according to the ninth aspect , wherein a cylinder protrudes slightly forward from the front upper portion of the crankcase,
An engine hanger mounting portion is formed at a position above the cell motor below the cylinder on the front wall of the crankcase.

According to the cam chain tensioner device of the internal combustion engine according to claim 1, the guide hole is formed at least upwardly in the lower part of the crankcase, and is a concave part that protrudes downward and opens upward in the cam chain chamber. Since the oil sump with the upper opening of the guide hole facing the inside is formed integrally with the crankcase, the oil is efficiently collected in the oil sump formed by opening the upper part at the lower part of the crankcase. Is guided from the upper opening of the guide hole along the push rod to the lid of the push rod and can flow into the oil chamber when the control valve is opened.
A guide hole is formed integrally with the crankcase together with the oil reservoir, a fastener is not required, the number of parts is small, the structure is simple, and the cost can be reduced.
The oil guide rib that protrudes from the cam chain chamber side wall of the crankshaft crankshaft bearing wall is formed to be inclined below the drive sprocket, and the oil reservoir is located below the lower end of the oil guide rib. Oil that drops from the sprocket and cam chain, etc., and oil that flows down along the wall surface of the bearing wall on the cam chain chamber side is received by the oil guide ribs and guided to the oil reservoir, and the oil is efficiently collected in the oil reservoir. I can.

  According to the cam chain tensioner device for an internal combustion engine according to claim 2, the upper opening facing the inside of the oil sump in the guide hole is arranged so that the front and rear guide walls constituting the upper part of the guide hole extend into the oil sump. The guide wall is formed to open upward and to the left and right sides. The push rod is inserted into the guide hole and is held slidably between the front and rear guide walls. The left and right openings between the front and rear guide walls are oiled. Since the push rod communicates with the reservoir, the push rod can be stably supported with a simple structure, and the oil accumulated in the oil reservoir is in contact with the outer peripheral surface of the push rod at the left and right openings between the front and rear guide walls. The control valve can be guided efficiently along the line.

According to the cam chain tensioner device for an internal combustion engine according to claim 3 , two oil sumps are arranged in the longitudinal direction of the vehicle body to form a front oil sump and a rear oil sump, and the front oil sump and the rear oil sump are defined as Because they communicate with each other, the oil level change of the oil accumulated in the oil sump with respect to the longitudinal movement of the vehicle body is suppressed, the amount of oil leaking from the oil sump is reduced, and the necessary amount of oil storage is always secured. Can do.

According to the cam chain tensioner device for an internal combustion engine according to claim 4, the front oil sump is located below the lower end of the oil guide rib, the front wall of the front oil sump protrudes forward, and the bottom and rear sides of the front oil sump The bottom of the oil sump is continuous while tilting diagonally downward toward the rear, and the upper opening of the guide hole faces the rear oil sump, so that the oil that has been guided by the oil guide ribs and flows down from the lower end The volume of the oil reservoir is expanded in such a way that the oil is transferred to the oil chamber inside the guide hole with the upper opening of the guide hole facing the rear oil reservoir that is deep at the bottom due to the slope of the bottom and has a large amount of oil storage. Can be supplied stably.

According to the cam chain tensioner device for an internal combustion engine according to claim 5 , since the oil return passage is formed below the front wall protruding forward of the front oil sump in the crankcase, the oil overflowing from the front oil sump Flows forward down the front wall that protrudes forward, enters directly into the oil return passage, and is quickly returned to the bottom of the crankcase.

According to the crank cam chain tensioner device for an internal combustion engine according to claim 6 , since one side wall in the vehicle body width direction of the oil sump formed in the crank case is constituted by contact of a separate side wall plate, The oil reservoir is open to the side, the crankcase can be easily molded, and the manufacturing cost can be reduced.

According to the cam chain tensioner device for an internal combustion engine according to claim 7 , the guide hole is formed so as to be inclined so that a lower end which is opened in a side wall of the crankcase and is closed by the tensioner bolt is located in front of the vehicle body from the upper end. A drain bolt that closes the drain hole formed in the bottom wall of the case is provided below the tensioner bolt in a side view of the vehicle body, so that the tensioner bolt that closes the lower end by tilting the guide hole and the drain bolt below the drain bolt The drain bolt that closes the hole can be brought close to make it compact.
Also, the tensioner bolt and drain bolt have different mounting positions, and the mounting direction can be different from the tensioner bolt, for example, the tensioner bolt is obliquely upward and the drain bolt is vertically upward. And the drain bolt can be prevented from operating incorrectly.

According to the cam chain tensioner device for an internal combustion engine according to claim 8, an oil sump is formed in the lower part of the crankcase so that the upper opening of the guide hole faces the inside, and the crankcase is provided in the cam chain chamber in which the oil sump is provided. Despite having a simple structure with a small number of parts, the mission chamber is formed by dividing the mission chamber behind the vehicle body in the longitudinal direction by a partition wall and forming a communication port at an obliquely upper portion of the oil reservoir in the partition wall. The oil scattered from the air enters the cam chain chamber through the communication port of the partition wall, falls on the cam chain, is used for lubrication, and is efficiently collected in an oil reservoir obliquely below.

According to the cam chain tensioner device for an internal combustion engine according to claim 9 , the internal combustion engine is mounted on the vehicle with the crankshaft oriented in the vehicle body width direction, and the cell motor and the intermediate gear are disposed below the front side of the crankcase that supports the crankshaft. The center of gravity of the vehicle body can be lowered, and the cell motor and the intermediate gear can be arranged by effectively utilizing the empty space below the front side of the crankshaft to avoid the enlargement of the internal combustion engine. it can.

According to the cam chain tensioner device for an internal combustion engine according to claim 10, the cylinder protrudes slightly forward from the front upper part of the crankcase, and the engine is placed on the front wall of the crankcase below the cylinder and above the cell motor. Since the hanger mounting portion is formed, the engine hanger mounting portion is provided using the space between the cylinder and the cell motor below it, and the internal combustion engine can be suspended stably.

Hereinafter, the internal combustion engine 1 according to the present invention is a SOHC type single-cylinder four-stroke internal combustion engine, and is mounted on a motorcycle with a crankshaft 10 oriented in the vehicle body width direction with respect to the vehicle body.
A transmission case 3 is integrally formed behind the crankcase 2 that rotatably supports the crankshaft 10 of the internal combustion engine 1 to constitute a power unit case.

  Referring to FIG. 1, a cylinder block 4 and a cylinder head 5 are sequentially stacked and fastened integrally on a diagonally upper side of the crankcase 2, and a cylinder head cover 6 is put on the cylinder head 5. The cylinder head 5 and the cylinder head cover 6 protrude from the crankcase 2 so as to be inclined forward slightly.

Referring to FIG. 2, the crankcase 2 is pivotally supported on the bearing wall 2Lw of the left crankcase 2L and the bearing wall 2Rw of the right crankcase 2R through main bearings 11 and 11 in a left-right split manner. Is done.
In the crankshaft 10, the crank webs 10w, 10w are positioned in the crank chamber 2S between the bearing walls 2Lw, 2Rw, the left and right crankshaft portions 10a, 10a protrude from the left and right outer sides of the bearing walls 2Lw, 2Rw, and the outer sides of the crankshafts 10 7 and 7 are covering.

  A drive sprocket 12 for a valve drive system is fitted to the left crankshaft 10a in the vicinity of the main bearing 11, and an AC generator 13 is provided at the left end. The driven mechanism is driven between the drive sprocket 12 and the AC generator 13. Gear 14 is fitted.

  On the other hand, a valve mechanism is constructed in the cylinder head 5, and the cam shaft 20 is pivotally supported in the vehicle body width direction so as to be sandwiched by the cam shaft holder 21 on the upper surface of the cylinder head 5. A driven sprocket 22 having a diameter approximately twice that of the drive sprocket 12 of the valve drive system is fitted to the left end.

A cam chain 23, which is an endless transmission chain, is placed between the driven sprocket 22 fitted to the camshaft 20 and the drive sprocket 12 fitted to the crankshaft 10. It is transmitted to the camshaft 20 at half the rotational speed.
The cam chain 23 is disposed in each cam chain chamber 2C, 4C, 5C of the crankcase 2, the cylinder block 4, and the cylinder head 5.

  A guide roller 24 having an intermediate diameter between the drive sprocket 12 and the driven sprocket 22 is rotatably supported in the cam chain chamber 4C of the cylinder block 4 to guide the rotation of the cam chain 23 on the front side and the rear side. doing.

The cam chain chamber 2C of the left crankcase 2L forms a common space with the ACG chamber 7S in which the AC generator 13 is covered by the left case cover 7, and extends to the left of the crankcase 2 near the left bearing wall 2Lw. A space surrounded by the protruding peripheral wall 2Ls corresponds to the cam chain chamber 2C.
The mission chamber 3S formed behind the crank chamber 2S is formed to bulge leftward to the rear of the cam chain chamber 2C.

  In the cam chain chamber 2C, a guide roller 25 is rotatably supported on the left bearing wall 2Lw at a front obliquely upper position of the drive sprocket 12 so as to guide the rotation of the cam chain 23 on the front side.

Referring to FIG. 3, a tensioner arm 31 of a cam chain tensioner device 30 is pivotally supported by a pivot bolt 32 at the rear of the drive sprocket 12 in the cam chain chamber 2C. .
A tensioner roller 33 is rotatably supported at the tip of the arm extending upward from the tensioner arm 31, and the tip of the arm extending downward forms a contact end 31e.

  The push rod 36 of the tensioner lifter 35 abuts against the abutting end 31e of the tensioner arm 31 and presses and biases, so that the tensioner roller 33 at the tip of the arm extending upward is rotated on the rear side of the cam chain 23. An appropriate tension is applied to the cam chain 23 by pressing the moving part.

The tensioner lifter 35 is formed below the drive sprocket 12 that is fitted to the crankshaft 10 that is pivotally supported by the left crankcase 2L (see FIGS. 1 and 2).
Referring to FIG. 4 which is a perspective view of the left crankcase 2L and FIG. 5 which is an enlarged side view of the main part, a bearing circular hole 11h in the peripheral wall 2Ls extending leftward from the left bearing wall 2Lw of the left crankcase 2L. The inclined portion corresponding to the lower side of the drive sprocket 12 is perforated so that the guide hole 37 is inclined from the upper part on the inner side of the peripheral wall 2Ls to the lower part on the outer side of the peripheral wall 2Ls, and passes through the cam chain chamber 2C and the outside. Yes.

  An upper portion of the guide hole 37 above the peripheral wall 2Ls is formed in the oil receiving portion 39, and a lower half portion of the guide hole 37 is formed in the guide cylinder portion 38 extending obliquely downward from the peripheral wall 2Ls. The opening end surface 38s at the lower end of the cylinder is slightly higher than the lowest bottom wall constituting the oil pan 2p which is the bottom of the crank chamber 2S.

  The oil receiving portion 39 constitutes an oil sump 40 (indicated by a broken-line grid hatch in FIGS. 5 and 6) that is a concave portion that is recessed downward and opened upward, and a front wall that projects forward of the oil sump 40. A bolt boss part 39f is formed in the part, the rear wall is formed by a rear guide wall 39r so that the rear inner surface of the guide hole 37 extends, and the left bearing wall 2Lw constitutes the right side wall. Is missing, and instead a side wall plate 41 is added to form the left side wall.

As shown in FIG. 4, the side wall plate 41 is a plate member having a triangular shape with a substantially acute apex angle. The other long side extending diagonally forward from the lower side 41b is the lower side 41b, and the front short side 41c is notched at the center to form irregularities.
The side wall plate 41 is provided with a mounting hole 41h near the short side 41c.

The side wall plate 41 is brought into contact with the left side surface of the oil receiving portion 39, the bolt 42 is passed through the mounting hole 41h through the washer 43, and is screwed into the bolt hole of the bolt boss portion 39f of the oil receiving portion 39. 41 is attached to the oil receiving portion 39 to serve as the left side wall of the oil sump 40.

A front guide wall 39c projects obliquely upward so that the front inner surface of the inclined guide hole 37 extends at the front and rear center position of the oil sump 40, and the oil sump 40 is separated from the front oil sump 40f by the front guide wall 39c. It is divided into side oil sump 40r.
However, there is a gap between the side wall plate 41 constituting the left side wall and the front guide wall 39c, and the front oil reservoir 40f and the rear oil reservoir 40r communicate with each other (see FIG. 6).

The bolt boss portion 39f of the front wall portion of the front oil sump 40f projects forward, and the bottom surface of the front oil sump 40f and the bottom surface of the rear oil sump 40r are continuous while being inclined obliquely downward toward the rear.

The upper opening of the guide hole 37 faces the rear oil reservoir 40r.
The upper opening facing the inside of the rear oil sump 40r of the guide hole 37 is such that the front guide wall 39c and the rear guide wall 39r constituting the upper part of the guide hole 37 extend into the rear oil sump 40r and the front guide wall 39c. The left and right openings between the front and rear guide walls 39c and 39r communicate with the rear oil reservoir 40r (see FIG. 6).

The push rod 36 is inserted into the guide hole 37 from the upper opening, and is supported slidably between the front and rear guide walls 39c and 39r protruding obliquely upward, so that the push rod 36 extends over a long length. It is supported stably.
Also, since the left and right openings between the front and rear guide walls 39c and 39r face the rear oil reservoir 40r, the oil accumulated in the rear oil reservoir 40r is pushed by the left and right openings between the front and rear guide walls 39c and 39r. It touches the outer peripheral surface.

The push rod 36 is a cylindrical member having an outer diameter slightly smaller than the inner diameter of the guide hole 37, and a plurality of circular holes 36 h are formed in the axial direction at a required portion of the cylindrical wall, and the oil that has touched the outer peripheral surface is the outer peripheral surface. The oil can be supplied into the cylinder of the push rod 36 from the circular hole 36h along the line.
A rubber head member 44 is fitted into the upper end opening of the push rod 36.
A control valve 45 is provided at the lower end opening of the push rod 36.

  In the control valve 45, a bottomed cylindrical valve seat 45s having a circular hole in the bottom wall is fitted slightly into the lower end opening of the push rod 36, and a ball 45b is loosely fitted in the cylinder of the valve seat 45s. A bottomed cylindrical valve cap 45c is applied to the opening of the valve seat 45s to prevent the ball 45b from dropping, and the ball 45b can be opened and closed in the circular hole of the valve seat 45s.

An internal thread is engraved in the vicinity of the opening of the guide hole 37 at the lower end of the guide cylinder portion 38, and a tensioner bolt 46 with a flange can be screwed to close the lower end opening of the guide hole 37.
As described above, the push rod 36 provided with the control valve 45 at the lower end is inserted into the guide hole 37 from above, the compression spring 47 is inserted into the guide hole 37 from below, and the lower end opening of the guide hole 37 is extended by the tensioner bolt 46. When the plug is closed, the push rod 36 is urged obliquely upward by the compression spring 47.

  Thus, the head member 44 at the upper end of the push rod 36 biased obliquely upward by the compression spring 47 contacts the contact end 31e of the tensioner arm 31, and the tensioner arm 31 is seen in a side view of FIG. As a result, the tensioner roller 33 at the other end of the tensioner arm 31 presses the rear rotating portion of the cam chain 23 to apply a constant tension to the cam chain 23. .

As described above, the oil accumulated in the oil reservoir 40 is supplied to the inside of the cylinder of the push rod 36 communicated via the circular hole 36h of the push rod 36, and is compressed downward from the lower part of the cylinder and further from the control valve 45. The oil chamber 37a which is the guide hole 37 of the guide cylinder portion 38 in which the spring 47 is interposed is filled.
Therefore, the push rod 36 is pushed by the tensioner arm 31, but the oil in the oil chamber 37a below the control valve 45 in the guide hole 37 presses the ball 45b against the circular hole of the valve seat 45s and closes the valve. In this state, the push rod 36 is prohibited from moving backward (down).

When the cam chain 23 is loosened, the push rod 36 moves forward by the urging force of the compression spring 47, swings the tensioner arm 31, and presses the tensioner roller 33 deeply with the cam chain 23 to maintain the tension.
At this time, the control valve 45 is opened and the oil in the push rod 36 enters the lower oil chamber 37a from the control valve 45 so that the push rod 36 can move forward.
The push rod 36 that has moved forward is prohibited from retreating by closing the control valve 45, and therefore, the cam chain 23 is not loosened again, and can always be maintained with moderate tension applied to the cam chain 23.

Referring to FIG. 4 which is a perspective view of the left crankcase 2L, an oil guide rib 50 inclined obliquely rearward and downward below the guide roller 25 and the drive sprocket 12 in the cam chain chamber 2C is formed on the left bearing wall 2Lw of the crankcase 2. It protrudes to the left.
The front portion of the oil sump 40 is located directly below the lower end of the oil guide rib 50, and a gap 51 is provided between the bolt boss portion 39 f serving as the front wall of the oil sump 40 and the lower end of the oil guide rib 50.

On the other hand, at the rear of the oil sump 40, there are an obliquely upper portion of the peripheral wall 2Ls of the left crankcase 2L, which is a partition wall for partitioning the cam chain chamber 2C and the rear mission chamber 3S, and a portion of the left bearing wall 2Lw in contact therewith. A communication port 52 is formed for communication between the cam chain chamber 2C and the rear mission chamber 3S.
An inclined surface 53 from the lower end of the communication port 52 toward the oil reservoir 40 is formed on the peripheral wall 2Ls.

  Below the front end of the bolt boss portion 39f of the oil reservoir 40, there is a minimum portion of the peripheral wall 2Ls, and an opening serving as an oil return passage 54 is formed in the minimum bearing portion and the left bearing wall 2Lw in contact with the same portion. The cam chain chamber 2C and the crank chamber 2S communicate with each other and communicate with an oil pan 2p at the bottom of the crank chamber 2S.

  Since the left crankcase 2L constituting the cam chain chamber 2C has the above-described structure, oil dropped by the rotation of the drive sprocket 12 and the guide roller 25 and the rotation of the cam chain 23 and the cam of the left bearing wall 2Lw Oil that flows down along the wall surface on the chain chamber side is received by the inclined oil guide rib 50 and guided downward, and the oil that is guided by the oil guide rib 50 and flows down from the lower end is received by the front oil sump 40f. The volume of 40 is expanded and can flow into the lower front oil reservoir 40f from the lower end of the oil guide rib 50, so that the oil can be efficiently collected in the oil reservoir 40 (the flow of oil in FIG. 3). (See dashed arrow).

  Further, a part of the oil scattered by the rotation of the transmission gear in the mission chamber 3S from the communication port 52 communicating with the cam chain chamber 2C obliquely above and behind the oil reservoir 40 and the mission chamber 3S behind is stored on the cam chain chamber 2C side. Enters the cam chain 23 and is used for lubrication, and the oil poured on the inclined surface 53 is guided by the inclined surface 53 and flows into the oil reservoir 40 obliquely below, and is efficiently collected (oil (See the broken line arrow in FIG. 3).

  In this manner, oil guided to the front oil guide rib 50 flows into the oil reservoir 40 from the front, and oil introduced from the rear communication port 52 and guided to the inclined surface 53 flows from the rear and from above. However, the oil flows along the left bearing wall 2Lw, and the scattered oil is poured from above, and the oil is collected in the oil reservoir 40 very efficiently.

  The oil reservoir 40 has an upper opening of the guide hole 37 facing the rear oil reservoir 40r having a deep bottom and a large amount of oil stored due to the inclination of the bottom surface, and the oil accumulated in the rear oil reservoir 40r passes through the guide hole 37. The upper opening, that is, the left and right openings between the front and rear guide walls 39c and 39r touches the outer peripheral surface of the push rod 36 and is sufficiently supplied into the push rod 36 from the circular hole 36h in the cylinder wall. Oil can be stably supplied to 37a.

  Two oil reservoirs 40 are arranged in the longitudinal direction of the vehicle body by the front guide wall 39c to form a front oil reservoir 40f and a rear oil reservoir 40r, and the front oil reservoir 40f and the rear oil reservoir 40r communicate with each other. Therefore, it is possible to suppress the change in the oil level of the oil accumulated in the oil sump 40 with respect to the longitudinal movement of the vehicle body, to reduce the amount of oil leaking from the oil sump 40, and to always ensure the necessary amount of oil stored in the sump 40. it can.

As described above, since the oil sump 40 is integrally formed with the crankcase 2 together with the guide hole 37, there is no need for fasteners, the number of parts is small, the structure is simple, and the cost can be reduced. it can.
Since one side wall in the vehicle body width direction of the oil sump 40 formed in the crankcase 2 is configured by contact with a separate side wall plate 41, the oil sump 40 on the crankcase 2 side is open to the side, The crankcase 2 can be easily molded, and the manufacturing cost can be further reduced.

The oil overflowing from the oil sump 40 flows forward downward through the bolt boss 39f, which is the front wall protruding forward, and directly enters the crank chamber 2S through the lower oil return passage 54 (broken line arrow in FIG. 3). (See), and quickly returned to the oil pan 2p at the bottom of the crankcase 2 .

A drain bolt hole is formed in the lowest bottom wall of the oil pan 2p, and the drain bolt 55 is screwed into the drain bolt hole from the bottom to the top and is closed.
The drain bolt 55 screwed into the drain bolt hole is attached close to the lower side of the tensioner bolt 46 that closes the lower end opening of the guide hole 37 of the guide cylinder portion 38 in a side view shown in FIG.

  As shown in FIGS. 2 and 3, the tensioner bolt 46 and the drain bolt 55 are arranged at positions close to each other. However, the tensioner bolt 46 and the drain bolt 55 are installed at different positions, and the installation direction of the tensioner bolt 46 is also the same. Since the drain bolt 55 is obliquely upward and different vertically, it is possible to avoid operating the tensioner bolt 46 and the drain bolt 55 in error during maintenance.

In the internal combustion engine 1, a cell motor 60 is disposed below the front side of the crankcase 2.
As shown in FIG. 1, the cell motor 60 is installed with a drive shaft 61 protruding leftward, and a drive gear 61 a is formed at the shaft end of the drive shaft 61.
An intermediate gear shaft 62 is disposed behind the drive shaft 61 in parallel with the drive shaft 61, and an intermediate large-diameter gear 63b and an intermediate small-diameter gear 63s are integrally supported on the intermediate gear shaft 62.

  The drive gear 61a of the drive shaft 61 of the cell motor 60 meshes with the intermediate large-diameter gear 62b, and the intermediate small-diameter gear 63s integrated with the intermediate large-diameter gear 62b meshes with the driven gear 14 fitted to the crankshaft 10 to start. The mechanism is configured.

The internal combustion engine 1 mounted on a vehicle with the crankshaft 10 oriented in the vehicle body width direction has a space on the lower front side of the crankshaft 10 and effectively uses the space on the lower front side of the crankcase 2. Since the cell motor 60 and the intermediate gears 63b and 63s are provided, the internal combustion engine 1 can be prevented from being enlarged.

  In the internal combustion engine 1, a cylinder block 4 and a cylinder head 5 project from the front upper part of the crankcase 2 slightly forward, and a cylinder block 4 tilted forward on the front wall of the crankcase 2 as shown in FIG. 1. An engine hanger mounting portion 70 is formed so as to protrude below the front wall of the cell motor 60.

  An engine hanger mounting portion 70 is provided by utilizing the space between the cylinder block 4 and the cell motor 60 below the cylinder block 4, and the engine hanger mounting portion 70 is not bulky, and the internal combustion engine 1 is stably suspended. be able to.

1 is a side view in which a part of an internal combustion engine according to an embodiment of the present invention is omitted. FIG. 4 is a developed sectional view (sectional view taken along line II-II in FIG. 3) of the internal combustion engine. It is the side view to which the principal part was expanded as a partial cross section of the internal combustion engine. It is a perspective view of a left crankcase and a side wall plate. It is a side view of a left crankcase. FIG. 6 is a sectional view taken along line VI-VI in FIG. 5.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine, 2 ... Crank case, 2L ... Left crank case, 2Lw ... Left bearing wall, 2Ls ... Peripheral wall, 2C ... Cam chain chamber, 2S ... Crank chamber, 2R ... Right crank case, 3 ... Mission case, 3S ... 4 ... Cylinder block, 5 ... Cylinder head, 6 ... Cylinder head cover, 7 ... Case cover, 10 ... Crankshaft, 11 ... Main bearing, 12 ... Drive sprocket, 13 ... AC generator, 14 ... Driven gear,
20 ... cam shaft, 21 ... cam shaft holder, 22 ... driven sprocket, 23 ... cam chain, 24 ... guide roller, 25 ... guide roller,
30 ... Cam chain tensioner device, 31 ... Tensioner arm, 32 ... Pivot bolt, 33 ... Tensioner roller , 35 ... Tensioner lifter, 36 ... Push rod, 37 ... Guide hole, 37a ... Oil chamber, 38 ... Guide cylinder, 39 ... Oil receiving part, 39f ... bolt boss part, 39c ... front guide wall, 39r ... rear guide wall,
40 ... Oil sump, 41 ... Side wall plate, 42 ... Bolt, 43 ... Washer, 44 ... Head member, 45 ... Control valve, 46 ... Tensioner bolt, 47 ... Compression spring,
50 ... Oil guide rib, 51 ... Gap, 52 ... Communication port, 53 ... Inclined surface, 54 ... Oil return passage, 55 ... Drain bolt,
60 ... cell motor, 61a ... drive gear, 62 ... intermediate gear shaft, 63b ... intermediate large diameter gear, 63s ... intermediate small diameter gear, 70 ... engine hanger mounting part.

Claims (10)

A drive sprocket (12) fitted to a crankshaft (10) rotatably supported by a crankcase (2) of an internal combustion engine and a driven sprocket (12) fitted to a camshaft (22) of a valve train ) And a pressing member (31, 33) that presses and acts on an endless cam chain (23) spanned in the cam chain chamber (2C),
A push rod (36) that is slidably inserted into the guide hole (37) and press-contacts the pressing member (31, 33);
An oil chamber (37a) formed by being covered with a lid (45s) of the push rod (36) inside the guide hole (37);
A control valve (45) provided on the lid portion (45s) of the push rod (36) and allowing oil to flow into the oil chamber (37a) while preventing oil from flowing out of the oil chamber (37a). When,
A compression spring (47) interposed in the oil chamber (37a) and biasing the push rod (36) in the protruding direction;
In the cam chain tensioner device for an internal combustion engine that constantly applies a predetermined tension to the cam chain (23),
The guide hole (37) is formed at least upwardly in the lower part of the crankcase (2L),
An oil sump (40) is formed integrally with the crankcase (2L), which is recessed downward and is open upward to the cam chain chamber (2C), with the upper opening of the guide hole (37) facing inside. ,
An oil guide rib (50) protruding from the wall surface on the cam chain chamber (2C) side of the bearing wall (2Lw) of the crankshaft (10) of the crankcase (2L) is inclined below the drive sprocket (10). Formed,
The cam chain tensioner device for an internal combustion engine , wherein the oil reservoir (40) is located below a lower end of the oil guide rib (50) . The upper opening facing the inside of the oil reservoir (40) of the guide hole (37) is such that the front and rear guide walls (39c, 39r) constituting the upper portion of the guide hole (37) are located inside the oil reservoir (40). It is formed to extend upward and to the left and right sides by the front and rear guide walls (39c, 39r),
The push rod (36) is inserted into the guide hole (37) and is supported slidably between the front and rear guide walls (39c, 39r).
The cam chain tensioner device for an internal combustion engine according to claim 1, wherein left and right openings between the front and rear guide walls (39c, 39r) communicate with the oil reservoir (40). Two oil sumps (40) are arranged in the longitudinal direction of the vehicle body to form a front oil sump (40f) and a rear oil sump (40r),
The cam chain tensioner device for an internal combustion engine according to claim 1 or 2, wherein the front oil sump (40f) and the rear oil sump (40r) communicate with each other. The front oil sump (40f) is located below the lower end of the oil guide rib (50),
The front wall (39f) of the front oil sump (40f) protrudes forward;
The bottom surface of the front oil sump (40f) and the bottom surface of the rear oil sump (40r) are continuous while being inclined obliquely downward toward the rear,
The cam chain tensioner device for an internal combustion engine according to claim 3 , wherein an upper opening of the guide hole (37) faces the rear oil reservoir (40r). The internal combustion engine according to claim 4, wherein the crankcase (2L) has an oil return passage (54) formed below a front wall (39f) protruding forward of the front oil sump (40f). Cam chain tensioner device. Claim from claim 1 wherein the side wall of the vehicle body width direction of reservoir the oil is formed in the crankcase (2L) (40) is characterized in that it is constituted by the abutment of the side wall plate (41) separate The cam chain tensioner device for an internal combustion engine according to any one of claims 5 to 5 . The guide hole (37) is formed so as to be inclined so that the lower end which is opened in the side wall of the crankcase (2L) and is closed by the tensioner bolt (46) is located in front of the vehicle body from the upper end.
According claim 1, wherein said that the drain bolt to plugging the drain bolt hole formed in the bottom wall of the crankcase (2L) (55) is provided below the tensioner bolt (46) when the body is viewed from the side The cam chain tensioner device for an internal combustion engine according to any one of items 6 to 6 . The crankcase (2L) is formed by partitioning a transmission chamber (3S) with a partition wall (2Lw) behind the cam chain chamber (2C) in which the oil reservoir (40) is provided in the longitudinal direction of the vehicle body,
The internal combustion engine according to any one of claims 1 to 7, wherein a communication port (52) is formed at an obliquely upper portion of the oil reservoir (40) in the partition wall (2Lw). Cam chain tensioner device. The internal combustion engine is mounted on the vehicle with the crankshaft (10) oriented in the vehicle body width direction,
Of claims 1 to 8, characterized in that arranged between the starter motor (60) an intermediate gear (63 b, 63s) to the lower front side of the crankcase that journals the crankshaft (10) (2) The cam chain tensioner device for an internal combustion engine according to claim 1. Cylinder (4) is projected from the front upper part of the crankcase (2) slightly tilted forward,
The internal combustion engine according to claim 9 , wherein an engine hanger mounting portion (70) is formed in a portion of the front wall of the crankcase (2) below the cylinder (4) and above the cell motor (60). Engine cam chain tensioner device.

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