JP4675341B2 - Valve mechanism of internal combustion engine - Google Patents

Description

  The present invention relates to a valve mechanism for an internal combustion engine.

  In a valve operating mechanism in which a rocker arm that opens and closes a valve is pivotally supported by a rocker arm shaft, an example in which an oil discharge port is formed in communication with the rocker arm shaft and the rocker arm in which an oil passage is formed (see Patent Document 1). is there.

No. 7-41849

  In Patent Document 1, the rocker arm shaft is installed and supported by bearing portions of a pair of cam holders facing each other, and the rocker arm is pivotally supported so as to be sandwiched between bearings on both sides.

Since the axial width of the rocker arm is smaller than the distance between the pair of cam holders, the two bearing portions of the cam holder that support both ends of the rocker arm shaft extend to the position where the rocker arm is sandwiched, and the cam holder is enlarged.
Conversely, it is conceivable to extend the rocking base of the rocker arm in the axial direction, but the rocker arm itself becomes large.

Therefore, there is an example (Patent Document 2) in which a positioning spring composed of a compression coil spring is interposed instead of extending the bearing portion.
However, since the rocker arm is biased in the axial direction by interposing the spring, friction is generated in the rocker arm swinging.

JP 2004-316633 A

  The present invention has been made in view of such points, and the object of the present invention is to restrict the movement of the rocker arm in the axial direction with a simple configuration without increasing the size of the bearing portion or the rocker arm and without generating friction. It is the point which provides the valve operating mechanism of the internal combustion engine which can do.

In order to achieve the above object, according to the first aspect of the present invention, a rocker arm (58) is pivotally supported on a rocker arm shaft (57) supported and supported between bearings, and one end of the rocker arm (58) is connected to the rocker arm shaft (57). In the valve operating mechanism of the internal combustion engine, which is in sliding contact with the cam (53i) formed on the camshaft (53) and whose other end is driven to open and close the valve (56i) via the adjusting screw (58s), the rocker arm shaft (57) A cylindrical plate (61) inserted through the stopper plate is interposed between the bearings to restrict the movement of the rocker arm (58) in the axial direction, and to stop the rocker arm shaft (57) in the axial direction. with 65) and prevents rotation of the collar engagement piece of the stopper plate (65) (notch 65c) is provided on the collar (61) (wherein engages the 61p) color (61) The valve operating mechanism of the internal combustion engine was used.

According to a second aspect of the present invention, in the valve operating mechanism of the internal combustion engine according to the first aspect , the stopper plate (65) is engaged with a notch (57e) formed at an end of the rocker arm shaft (57). A shaft engaging piece (65bu) for preventing the rocker arm shaft (57) from rotating is formed.
According to a third aspect of the present invention, in the valve operating mechanism of the internal combustion engine according to the first or second aspect, an oil passage (57a) is formed in the rocker arm shaft (57) in the axial direction and penetrates in the radial direction. An oil discharge path (57c) communicating with the outer peripheral surface is formed at a predetermined position in the axial direction, and an oil discharge hole (61c) penetrating in the radial direction is formed in the collar (61). It is formed at a predetermined position corresponding to (57c).

According to the valve mechanism of the internal combustion engine according to claim 3, the axial movement of the rocker arm (58) is regulated by interposing the cylindrical collar (61) inserted through the rocker arm shaft (57) between the bearings. Therefore, the axial movement of the rocker arm (58) can be regulated with a simple configuration that avoids an increase in the size of the bearing portion such as the cam holder or the rocker arm (58) and avoids the occurrence of friction, and the collar (61 ) Is formed in a predetermined position corresponding to the oil discharge passage (57c) of the rocker arm shaft (57), and the collar (61) is rotated by the stopper plate (65). Therefore, the oil supply to the required part of the rocker arm (58) can be easily ensured.

According to the valve mechanism for an internal combustion engine according to claim 1, stopper plate for regulating the movement in the axial direction of the rocker arm shaft (57) (65), notch provided the piece in color (61) (61p ) To prevent the collar (61) from rotating, so that one stopper plate (65) restricts the axial movement of the rocker arm shaft (57) and prevents the collar (61) from rotating. The assembly work can be simplified with a small number of parts.

According to the valve mechanism of the internal combustion engine according to claim 2 , the stopper plate (65) is formed with a shaft engaging piece (65bu) that prevents the rocker arm shaft (57) from rotating. The stopper plate (65) prevents rotation of the collar (61) and restricts movement and rotation of the rocker arm shaft (57) in the axial direction, simplifying assembly work with fewer parts. be able to.

Hereinafter, an embodiment according to the present invention will be described with reference to FIGS.
FIG. 1 is a side view of a scooter type motorcycle 1 according to an embodiment to which the present invention is applied.

In the present embodiment, the front, rear, left and right are determined based on the state in which the vehicle is directed forward.
The vehicle body front portion 1f and the vehicle body rear portion 1r are connected via a low floor portion 1c, and the vehicle body frame forming the skeleton of the vehicle body is generally composed of the down tube 3 and the main pipe 4.

  That is, the down tube 3 extends downward from the head pipe 2 at the front part 1f of the vehicle body, the down tube 3 is bent horizontally at the lower end and extends rearward under the floor 1c, and a pair of left and right main pipes 4 at the rear end. The main pipe 4 rises obliquely rearward from the connecting portion, bends horizontally at a predetermined height, and extends rearward.

A fuel tank 5 and the like are supported by the main pipe 4, and a seat 6 is disposed above the fuel tank 5 and the like.
On the other hand, at the vehicle body front portion 1f, a handle 11 is provided above and supported by the head pipe 2, a front fork 12 extends downward, and a front wheel 13 is supported at the lower end thereof.

  A bracket 15 projects from the lower end of the rising portion of the main pipe 4, and the power unit 20 is connected to the bracket 15 via a link member 16 so as to be swingable.

  The power unit 20 is mounted with a single-cylinder four-stroke water-cooled internal combustion engine 30 at a front portion of the power unit 20 in a posture in which the cylinder block 32 is largely inclined to a substantially horizontal state. The protruding end portion of the hanger bracket 18 is connected to the link member 16 via a pivot shaft 19.

In the power unit 20, a belt-type continuously variable transmission 46 is formed from the internal combustion engine 30 to the rear, and a rear wheel 21 is provided on a rear axle 21a that is pivotally supported by a speed reduction mechanism 38 provided at a rear portion thereof.
A rear cushion 22 is interposed between the upper end of the speed reduction mechanism 38 and the upper bent portion of the main pipe 4.

An upper part of the power unit 20 is provided with a throttle body 25 connected to an intake pipe 23 extending from an upper part of a cylinder head 33 that is largely inclined forward of the internal combustion engine 30, and an air cleaner 26 connected to the throttle body 25. Yes.
The intake pipe 23 is provided with an injector 24 that injects fuel toward the intake port (see FIG. 4).

On the other hand, the exhaust pipe 27 extending from the lower portion of the cylinder head 33 extends downward while being biased to the right side, curves backward so as to wind the right hanger bracket 18, and is provided to the right of the portion corresponding to the crankcase. A lower part of a radiator 80 described later extends rearward and is connected to the muffler 28.
The muffler 28 is suspended from the crankcase 31 by a bracket 29 and is located on the right side of the rear wheel 21.

The front part 1f of the vehicle body is covered from the front and back by the front cover 9a and the leg shield 9b from the left and right sides by the front lower cover 9c, and the center part of the handle 11 is covered by the handle cover 9d.
The floor portion 1c is covered with a side cover 9e, and the vehicle body rear portion 1r is covered with a body cover 10 from the left and right sides.

FIG. 2 is a longitudinal sectional view of the power unit 20.
In the internal combustion engine 30, a connecting rod 43 connects a piston 42 that reciprocates in a cylinder liner 44 of a cylinder block 32 and a crank pin 40 a of a crankshaft 40.
The crankcase 31 is configured by combining a left crankcase 31L and a right crankcase 31R which are split into left and right parts. The right crankcase 31R forms a half of the crankcase portion, and the left crankcase 31L The crankcase part 31a is long and has a transmission case part 31b at the center with reference to FIG. 1, and a reduction gear case part 31c at the rear part.

  The left open surface of the left crankcase 31L is covered with a transmission case cover 36 that is a part of the transmission case, the belt type continuously variable transmission 46 is accommodated therein, and the right open surface of the rear reduction gear case 31c. Is covered with a speed reducer case 37, and a speed reduction mechanism 38 is accommodated therein.

  In the so-called crankcase of the crankcase portion 31a and the right crankcase 31R, the crankshaft 40 is rotatably supported by the left and right main bearings 41, 41, and the right extension of the extension portions extending in the left-right horizontal direction is provided. The part is provided with a cam chain drive sprocket 55a, an oil pump drive gear 55b, and an AC generator 72, and the left extension part is provided with a centrifugal weight 47 and a drive pulley 48a of a belt type continuously variable transmission 46.

  The belt-type continuously variable transmission 46 is configured such that a V-belt 49 is stretched between a driving pulley 48a and a driven pulley 48b provided on an input shaft 38a of the speed reduction mechanism 38, and power is transmitted. The winding weight of the V belt 49 in the driving pulley 48a is changed by the centrifugal weight 47 that moves in response to the change, and at the same time, the winding diameter in the driven pulley 48b is automatically changed to change continuously.

  The four-cycle internal combustion engine 30 employs an SOHC type valve system. A valve mechanism 50 is provided in the cylinder head cover 34, and a cam chain 51 that transmits power to the valve mechanism 50 includes a camshaft 53. The cam chain chambers 52c, 52s, and 52h are provided in communication with the right crankcase 31R, the cylinder block 32, and the cylinder head 33.

  That is, the cam chain 51 is connected to the cam chain chambers 52c, 52s, 52h between the driven sprocket 54 fitted to the right end of the cam shaft 53 oriented in the horizontal direction and the drive sprocket 55a fitted to the crankshaft 40. It is passed through the inside.

  Referring to FIG. 3, an oil pump 61 is provided between a right crankcase 31 </ b> R and a partition wall 70, which will be described later, and a pump drive shaft 62 is rotatably mounted. The oil pump 61 is fitted on the pump drive shaft 62. The driven gear 63 meshes with an oil pump driving gear 55b formed integrally with the cam chain driving sprocket 55a.

An oil passage 65a extends downward from the oil pump 61 to the right crankcase 31R, and an oil passage 65b extends horizontally from the middle of the oil passage 65a to the left crankcase 31L to reach the oil strainer 66. Yes.
Below the oil strainer 66 is an oil reservoir 65c.

  Therefore, when the oil pump 61 is driven by the rotation of the crankshaft 40 through the meshing of the drive gear 55b and the driven gear 63, the oil is pumped from the oil reservoir 65c via the oil strainer 66 and supplied to the required location.

A spark plug 45 is inserted into the cylinder head 33 from the opposite side (left side) of the cam chain chamber 52 toward the combustion chamber 33a.
Referring to FIG. 4, the intake port 33i extends upwardly from the combustion chamber 33a of the cylinder head 33 tilted greatly forward and is connected to the intake pipe 23, and the exhaust port 33e curves downward from the combustion chamber 33a. And is connected to the exhaust pipe 27 .

  As shown in FIG. 4, the valve mechanism 50 in the cylinder head cover 34 is greatly inclined forward to a state where the cylinder is nearly horizontal, and therefore an intake valve 56i for opening and closing the opening of the intake port 33i to the combustion chamber 33a is provided. An exhaust valve 56e that is disposed above the camshaft 53 and opens and closes an opening of the exhaust port 33e to the combustion chamber 33a is disposed below the camshaft 53.

  The camshaft 53 is rotatably supported by bearings 56 and 56 on the left side wall of the cylinder head 33 and the inner side wall 33c constituting the cam chain chamber 52h, and a driven sprocket 54 is provided at the right end protruding from the right side bearing 56. It is inserted.

As shown in FIG. 4, an intake rocker arm shaft 57 and an exhaust rocker arm shaft 59, which are respectively disposed at diagonally upper and lower positions in front of the camshaft 53, are installed between the left side wall of the cylinder head 33 and the inner wall 33c (see FIG. 2). Has been.
The intake rocker arm shaft 57 and the exhaust rocker arm shaft 59 are in a vertical position with respect to each other, and a roller 58r pivotally supported on one end of an intake rocker arm 58 pivotably attached to the upper intake rocker arm shaft 57 is an intake of the camshaft 53. An adjusting screw 58s that contacts the cam 53i and is screwed to the other end contacts the end of the valve stem 56is of the intake valve 56i that is biased by the valve spring 56ib.

Similarly, a roller 60r pivotally supported at one end of an exhaust rocker arm 60 pivotably attached to the lower exhaust rocker arm shaft 59 is in contact with the exhaust cam 53e of the camshaft 53 and screwed to the other end. The screw 60s contacts the end of the valve stem 56es of the exhaust valve 56e biased by the valve spring 56eb.
Accordingly, the rotation of the camshaft 53 causes the intake cam 53i and the exhaust cam 53e to swing the intake rocker arm 58 and the exhaust rocker arm 60, respectively, so that the intake valve 56i and the exhaust valve 56e are opened and closed at a predetermined timing.

  2 and 3, the inner wall 31Rc and the right side wall 31Rr constituting the cam chain chamber 52c of the right crankcase 31R have an opening through which the crankshaft 40 passes, and the crankshaft is located in the opening of the inner wall 31Rc. A main bearing 41 that pivotally supports 40 is fitted, a large opening of the right side wall 31Rr is closed from the right by a partition wall 70 attached by a bolt 71, and the crankshaft 40 passes through a cylindrical portion 70a of the partition wall 70.

  In the AC generator 72, a bowl-shaped outer rotor 74 is fixed to the right end portion of the crankshaft 40 passing through the cylindrical portion 70a of the partition wall 70 via an ACG boss 73, and is disposed on the inner peripheral surface thereof in the circumferential direction. An inner stator 76 around which a stator coil 77 is wound is fixed to the cylindrical portion 70 a of the partition wall 70 inside the magnet 75.

  The right side surface of the outer rotor 74 is mounted with a radiator fan board 78a having a disk shape with its center bulging, and the radiator fan board 78a is formed with a plurality of radiator fans 78 protruding rightward.

  The outer periphery of the outer rotor 74 of the AC generator 72 is generally surrounded by a peripheral wall 31Rs extending rightward from the right side wall 31Rr of the right crankcase 31R, and the outer periphery of the radiator fan 78 is surrounded by a shroud 90 described later. A radiator 80 is provided adjacent to the right side.

FIG. 4 is a right side view of the internal combustion engine 30 with the radiator 80 and the shroud 90 removed.
A slightly vertically long peripheral wall 31Rs of the right crankcase 31R covers the outer periphery of the outer rotor 74 of the AC generator 72.

Radiator mounting bosses 31Rb are formed to protrude further to the right from the end face of the peripheral wall 31Rs at four extending portions extending from the front and rear and the lower front and rear of the peripheral wall 31Rs to the outer peripheral side (see FIG. 3).
The right end surfaces of the four radiator mounting bosses 31Rb are on the same plane.

On the other hand, as shown in FIG. 5 (see FIG. 3), the radiator 80 has a structure in which a rectangular radiator core portion 81 is sandwiched between an upper radiator tank portion 82 and a lower radiator tank portion 83. In the radiator tank section 82, a cooling water supply port 82a extends upward and the opening is closed by a filler cap 85, and a cooling water introduction port 82b projects behind the front (left side) of the upper radiator tank section 82. ing.
At the front and rear ends of the long upper radiator tank portion 82, mounting brackets 82c and 82c are respectively provided with mounting holes.

On the other hand, the lower radiator tank portion 83 is provided with a drain cock 83a on the rear side, and a cooling water outlet 83b projects forward at the front end.
Mounting brackets 83c, 83c are formed with mounting holes at the front lower portion and the rear end, respectively.

  The front and rear mounting brackets 82c and 82c of the upper radiator tank portion 82 and the front and rear mounting brackets 83c and 83c of the lower radiator tank portion 83 are formed so as to protrude rightward on the outer peripheral side of the peripheral wall 31Rs of the right crankcase 31R. It corresponds to the radiator mounting boss 31Rb, and is fixed to the right crankcase 31R directly by fixing them together with bolts 86 (see FIG. 3).

Further, as shown in FIG. 5, the upper radiator tank portion 82 of the radiator 80 is formed with a shroud mounting bracket 82d with a mounting hole extending forward from the front mounting bracket 82c, and the rear mounting bracket 82c. A shroud mounting bracket 82d is also provided with a mounting hole so as to extend obliquely upward from the rear upper part of the upper radiator tank portion 82.
The lower radiator tank portion 83 also extends downward from the central portion, and a shroud mounting bracket 83d is formed with a mounting hole.

  A shroud 90 that surrounds the outer periphery of the radiator fan 78 is attached to the three shroud mounting brackets 82d, 82d, and 83d formed on the radiator 80 from the back side of the radiator 80.

  As shown in FIGS. 6 to 8, the shroud 90 is formed with a rectangular plate portion 91 having a large circular opening 91a formed at the center (the lower end edge partially bulges downward). A peripheral wall portion 92 that is curved from the front side of the circular opening 91a to the upper side and the rear side is formed on the back surface (left side surface) of the portion 91 so as to protrude.

The peripheral wall 92 corresponds to the peripheral wall 31Rs of the right crankcase 31R, and the end surfaces of the peripheral wall 92 abut each other, and the peripheral wall 92 surrounds the outer periphery of the radiator fan 78.
A deficient portion below the peripheral wall portion 92 forms an exhaust port 93, and a plurality of rectifying plates 94 are formed at the exhaust port 93 so as to protrude from the rectangular plate portion 91 at an angle in a direction of smoothly discharging the radiator wind. .

A pair of front and rear side pieces 95 and 95 projecting to the front side (right side) are formed on the front and rear side edges of the rectangular plate portion 91 so that the radiator 80 is sandwiched between the side pieces 95 and 95 facing each other. Fitted.
Cover attachment pieces 96 are formed so as to protrude forward along the right end surface above and below the front piece 95, and similarly, cover attachment pieces 96 are formed so as to protrude rearward along the right end surface above and below the rear piece 95.
The four cover mounting pieces 96 are respectively formed with screw holes 96a.

A mounting bracket 97 with the radiator 80 is formed at the upper front end of the rectangular plate portion 91, and the mounting bracket 98 extends from the upper portion of the peripheral wall portion 92 obliquely upward rearward and deflecting to the front side (right side). A mounting bracket 99 is formed extending downward from the center of the lower portion of the rectangular plate portion 91.
The three mounting brackets 97, 98, 99 are provided with mounting holes 97a, 98a, 99a, respectively.

The shroud 90 having the above shape is attached to the back side of the radiator 80.
The front and rear side edges of the radiator core portion 81 of the radiator 80 are guided so that the front and rear side pieces 95 and 95 of the rectangular plate portion 91 of the shroud 90 are sandwiched, and the front side of the rectangular plate portion 91 of the shroud 90 is placed behind the radiator core portion 81. The three mounting brackets 97, 98, 99 of the shroud 90 are aligned with the three shroud mounting brackets 82d, 82d, 83d of the radiator 80, and the rivets 100 are passed through the mounting holes and fastened.

  With the shroud 90 attached to the back side of the radiator 80 as described above, the radiator 90 is overlapped with the right crankcase 31R by the bolt 86 as described above by superimposing the shroud 90 on the right opening of the right crankcase 31R shown in FIG. Fix directly.

  Four radiator mounting bosses 31Rb formed to protrude rightward on the outer peripheral side of the peripheral wall 31Rs of the right crankcase 31R are formed to protrude to the outer periphery of the peripheral wall portion 92 of the shroud 90 and extend to the mounting brackets 97, 98, 99. Therefore, the radiator 80 separated from the right crankcase 31R with the shroud 90 therebetween is directly fixed and supported to the crankcase 31 by the four radiator mounting bosses 31Rb protruding without increasing the size of the crankcase 31. Can do.

  The peripheral wall portion 92 of the shroud 90 connected to the peripheral wall 31Rs of the right crankcase 31R that substantially surrounds the outer periphery of the AC generator 72 substantially surrounds the outer periphery of the radiator fan 78 (see FIG. 3).

FIG. 5 shows a right side view of a state in which the radiator 80 is attached to the right side surface of the internal combustion engine 30, and the radiator cover 105 is put on the surface (right side surface) of the radiator 80.
The radiator cover 105 includes a core cover portion 105c formed with a louver 106 that covers the radiator core portion 81 of the radiator 80 from the right side, a right side surface of the upper radiator tank portion 82 on the upper side of the core cover portion 105c, and a front surface to a front surface. The upper tank cover portion 105u for covering and the lower tank cover portion 105l for covering the right side surface and the lower surface of the lower radiator tank portion 83 from the front and back surfaces to the lower side of the core cover portion 105c.

Mounting brackets 107 are provided with mounting holes on the upper and lower sides of the front and rear side edges of the core cover portion 105c so as to correspond to the four cover mounting pieces 96 of the shroud 90, respectively.
Accordingly, the radiator cover 105 is placed on the surface (right side surface) of the radiator 80, the mounting brackets 107 are aligned with the four cover mounting pieces 96 of the shroud 90, and the screws 108 are inserted into the respective mounting holes. The screw hole 96a is screwed and tightened (see FIG. 2), and the radiator cover 105 is attached to the shroud 90 (see FIG. 1).

Next, the cooling water circulation system will be described.
Referring to FIGS. 2 and 5, a water pump 120 is attached to the right side surface of the cylinder head 33.
The water pump body 121 of the water pump 120 has a long cylindrical portion 121a that is long in the axial direction for rotatably supporting the pump drive shaft 123 via a bearing 125, and one open end thereof extends in the radial direction. The impeller 124 fitted to the water pump drive shaft 123 is partially accommodated in a radially extending and short axial portion 121b. The long cylindrical portion 121a connects the water pump drive shaft 123 to the cam. It is fitted and fixed to the right side wall of the cylinder head 33 so as to be coaxial with the shaft 53, and the left end of the pump drive shaft 123 is fitted into a fitting hole formed in the right end surface of the camshaft 53 and rotates coaxially. Configured as follows.

  A water pump cover 122 that covers the right opening of the short cylindrical portion 121b of the water pump body 121 and accommodates the impeller 124 together with the short cylindrical portion 121b is superimposed on the opening end surface of the short cylindrical portion 121b and fixed by a bolt 126.

The water pump cover 122 has a water suction tube portion 122b extending from the suction port portion 122a bulging rightward of the water pump drive shaft 123 along the right side surface of the cylinder head 33 toward the crankshaft 40, and the impeller. A discharge port part 122c extends obliquely rearward and downward from the lower part of the outer periphery of 124, and a discharge connection pipe 127 is further projected from the discharge port part 122c (see FIG. 5).
Further, an air vent 122d is formed in the upper part of the outer periphery of the impeller 124, and an air vent connecting pipe 128 protrudes obliquely rearward and upward from the air vent 122d.

A connecting flange 122bb is formed at the upstream end (rear end) of the water suction cylindrical portion 122b, and a thermostat 130 is attached to the connecting flange 122bb by connecting the connecting flange 130a.
In the thermostat 130, the bypass connection pipe 131 extends upward from the upper part, and the inflow connection pipe 132 extends downward from the lower part.

Further, as shown in FIGS. 5 and 9, a branch connecting pipe 135 that projects directly from the upper part of the right side surface of the cylinder head 33 to the uppermost part of the internal water jacket 33w is provided to the right. The main pipe 135a of the connection pipe 135 protrudes rightward and then bends backward.
A bypass branch pipe 136 branches from the upstream left and right horizontal portions of the main pipe 135a of the branch connection pipe 135 and protrudes rearward. Further, a small-diameter air vent branch pipe extends from the downstream front and rear horizontal parts of the main pipe 135a. 137 protrudes downward and is bent forward.
That is, the branch connection pipe 135 is a branch pipe that has a bypass branch pipe 136 and an air vent branch pipe 137 branched from the main pipe 135a and has four connection portions in total.

  Referring to FIG. 5, the main pipe 135a of the branch connection pipe 135 is connected by the cooling water inlet 82b projecting behind (left side) from the upper radiator tank 82 of the radiator 80 and the radiator inflow hose 140, and is bypassed. The branch pipe 136 is connected by a bypass connection pipe 131 and a bypass hose 141 of the thermostat 130, and the air vent branch pipe 137 is connected by an air vent connection pipe 128 of the water pump 120 and an air vent connection hose 142.

  The cooling water outlet 83b protruding forward from the lower radiator tank 83 of the radiator 80 and the inflow connecting pipe 132 of the thermostat 130 are connected by the radiator outlet hose 143, and the discharge connecting pipe 127 of the water pump 120 is connected to the cylinder block 32. The inflow connecting pipe 138 and the connecting hose 144 communicate with the water jacket 32w.

Referring to FIG. 5, the cooling water cooled by the radiator 80 is guided from the lower radiator tank 83 to the thermostat 130 by the radiator outlet hose 143.
The cooling water guided to the thermostat 130 is sucked into the water pump 120 from the thermostat 130 through the water suction tube portion 122b, and from the discharge port portion 122c of the water pump 120 to the water jacket 32w of the cylinder block 32 through the connecting hose 144. Supplied.

  The water jacket 32w of the cylinder block 32 communicates with the water jacket 33w of the cylinder head 33, and the cooling water that flows through the water jackets 32w and 33w and cools the cylinder block 32 and the cylinder head 33 is the right side surface of the cylinder head 33. A water path is formed to return from the branch connection pipe 135 protruding from the upper part to the upper tank part 82 of the radiator 80 via the radiator inflow hose 140.

  Further, the cooling water flowing through the water jackets 32w and 33w of the cylinder block 32 and the cylinder head 33 reaches the thermostat 130 through the bypass branch pipe 136 branched from the branch connection pipe 135, bypasses the radiator 80, and bypasses. A water path is formed.

During the warm-up operation in which the internal combustion engine 30 is not warmed, the thermostat 130 closes the water path flowing in from the radiator 80, opens the water path bypassed from the cylinder head 33, accelerates the warm-up in the water path that does not pass through the radiator 80, and warms up. If There enters the normal operation ends, the thermostat 130 opens the water path flowing from the radiator 80 to close the water path which bypasses the cylinder head 33, cylinder head 33 cooling water cooled by the radiator 80 from the cylinder block 32 And the cylinder block 32 and the cylinder head 33 are cooled.

  The air in the water pump 120 exits from the air vent 122d at the top of the water pump cover 122 to the upper branch connecting pipe 135 via the air vent connecting hose 142, and the radiator inflow hose is inclined slightly upward as it goes rearward. The air then passes through 140 to reach the upper radiator tank portion 82 of the radiator 80, and further reaches the upper portion where the filler cap 85 is located along the inclined upper wall of the upper radiator tank portion 82 so that air can be extracted from the water path.

A detailed assembly structure of the intake rocker arm 58 and the exhaust rocker arm 60 of the valve mechanism 50 in the internal combustion engine 30 as described above will be described below.
FIG. 10 is a front view of the cylinder head 33 tilted forward to near horizontal, with the cylinder head cover 34 removed and viewed from the mating surface 33d side. The intake rocker arm shaft 57 and the exhaust rocker arm shaft 59 positioned above and below each other Between the left bearing part 33L bulging inward from the left side wall (right side in FIG. 10) of the head 33 and the right bearing part 33R formed on the inner side wall 33c facing the left bearing part 33L, it is installed and supported. The

  The right bearing portion 33R has upper and lower bearing holes through which the intake rocker arm shaft 57 and the exhaust rocker arm shaft 59 penetrate, respectively, and the left bearing portion 33L has bearing recesses corresponding to both the bearing holes, respectively. The rocker arm shaft 57 and the exhaust rocker arm shaft 59 are passed through the upper and lower bearing holes from the right side of the right bearing portion 33R, and are inserted into and supported by the corresponding bearing recesses of the left bearing portion 33L.

In the cylinder head 33, work holes 57h and 59h are formed on the right side wall of the right bearing portion 33R across the cam chain chamber 52h at positions facing the upper and lower bearing holes, respectively (see FIG. 12). When the rocker arm shaft 57 and the exhaust rocker arm shaft 59 are passed through the upper and lower bearing holes, the intake rocker arm shaft 57 and the exhaust rocker arm shaft 59 are first inserted from the right side through the work holes 57h and 59h. Then, it is made to penetrate through the bearing hole of the right bearing portion 33R.
After the work, the work holes 57h and 59h are closed by the lid members 57f and 59f.

When the intake rocker arm shaft 57 is assembled, the intake rocker arm shaft 57 penetrates both the swing base of the intake rocker arm 58 and the cylindrical collar 61 interposed between the left bearing portion 33L and the right bearing portion 33R. To.
The intake rocker arm 58 in contact with the left bearing portion 33L is sandwiched between the collar 61 in contact with the right bearing portion 33R and the left bearing portion 33L, and is restricted from moving in the axial direction, and is positioned to the left.

Further, when the exhaust rocker arm shaft 59 is assembled, the exhaust collar rocker arm includes the cylindrical collar 62 interposed between the left bearing portion 33L and the right bearing portion 33R, the swing base portion of the exhaust rocker arm 60, and the cylindrical collar 63. The shaft 59 penetrates.
The exhaust rocker arm shaft 59 is sandwiched between a collar 62 in contact with the left bearing portion 33L and a collar 63 in contact with the right bearing portion 33R, the movement in the axial direction is restricted, and the center is positioned.

As shown in FIG. 13, the intake rocker arm shaft 57 has a cylindrical shape in which an oil passage 57a is formed in the axial direction. The left end of the oil passage 57a is open, but the right end is closed, and the right end A notch 57e that is missing in a semicircular shape is formed on the end surface of the closing portion.
An oil communication hole 57b is formed in the radial direction at the right end of the oil passage 57a in the intake rocker arm shaft 57, and a pair of oil discharge holes (corresponding to oil discharge passages) 57c, 57c are provided in the radial direction so as to face each other. The oil discharge hole 57d is formed in the radial direction at a different angle from the oil discharge hole 57c on the left side.

As shown in FIG. 14, the cylindrical collar 61 also has oil discharge holes 61c, 61c formed in a radial direction at predetermined locations corresponding to the oil discharge holes 57c, 57c of the intake rocker arm shaft 57. .
The collar 61 is formed with a notch 61p at a predetermined position on the right end side by notching the side wall in a tangential direction.
The exhaust rocker arm shaft 59 is not formed with an oil passage or the like.

  Stud bolts 68 for connecting the cylinder head 33 with the cylinder block 32 sandwiched between the crankcase 31 and the end surface of the right bearing portion 33R and the end surface of the left bearing portion 33L, which are flush with the mating surface 33d of the cylinder head 33, respectively. The nut 69 is screwed onto the protruding screw part with a washer 66 and tightened. The right bearing part 33R has a stopper plate 65 in place of the washer. Tighten together.

  The stopper plate 65 elongated in the vertical direction passes through the bearing hole from the right side of the right bearing portion 33R, and is inserted into and supported by the corresponding bearing recess of the left bearing portion 33L and the exhaust rocker arm shaft 57 and the exhaust rocker arm shaft. The right end face of 59 is restrained from the right side to restrict axial movement.

Referring to FIG. 15, stopper plate 65 has mounting holes 65aa and 65aa through which stud bolts 68 penetrate at the upper and lower end portions of mounting body portion 65a abutting against the end face of right bearing portion 33R. The stopper body 65b is formed by being bent backward at the right edge of the mounting body 65a.
The rear end edge 65bb of the stopper piece 65b is cut out in an arc shape avoiding the camshaft 53, the upper end portion 65bu corresponding to the shaft engaging piece corresponding to the right end of the intake rocker arm shaft 57 is substantially horizontal, and the exhaust rocker arm shaft 59 A lower end 65bd corresponding to the right end of the taper hangs down in a tapered manner.

On the other hand, a collar engaging piece 65c is bent backward at a position facing the upper end portion 65bu of the left end edge of the mounting body portion 65a of the stopper plate 65.
The collar engaging piece 65c is engaged with the notch 61p of the assembled collar 61.

  FIG. 16 is an explanatory view showing a state in which the intake rocker arm shaft 57, the exhaust rocker arm shaft 59, the collars 61, 62, 63 and the stopper plate 65 are assembled, and the intake rocker arm 58, the exhaust rocker arm 60, and the right bearing portion 33R. The left bearing portion 33L is omitted.

The stopper plate 65 engages with a notch 57e in which the upper end portion 65bu of the stopper piece 65b is missing in a semicircular shape on the end face of the right end closing portion of the intake rocker arm shaft 57, thereby rotating the intake rocker arm shaft 57 at a predetermined rotation angle. It is regulated.
The upper end portion 65bu of the stopper piece 65b is in contact with the end face of the right end closing portion of the intake rocker arm shaft 57 and restricts the movement of the intake rocker arm shaft 57 in the axial direction.
On the other hand, a lower end portion 65bd that hangs downward from the stopper piece 65b is in contact with the right end surface of the exhaust rocker arm shaft 59 to restrict the movement of the exhaust rocker arm shaft 59 in the axial direction.

  Further, the stopper plate 65 has its collar engaging piece 65c inserted through the intake rocker arm shaft 57 and bites into the notch 61p of the collar 61 fitted in a predetermined position to engage with the stopper plate 65, and the collar 61 rotates by a predetermined number of times. The movement angle is regulated.

  In this way, the intake rocker arm shaft 57 and the collar 61, whose rotations are both regulated by the stopper plate 65, are such that the oil discharge holes 57c and 57c of the intake rocker arm shaft 57 and the oil discharge holes 61c and 61c of the collar 61 coincide with each other. The oil can be discharged downward.

  An oil discharge hole 57d formed in a portion of the intake rocker arm shaft 57 where the intake rocker arm 58 is swingably fitted is formed obliquely downward and downward, and the oil discharge hole 57d is formed in the intake rocker arm 58. Oil can be supplied to lubricate the rocking base end of the intake rocker, and oil can be discharged obliquely rearward and downward at the same rocking angle as the oil discharge hole 58d formed in the rocking base end of the intake rocker arm 58 It is said.

The bolt hole 68a of the cylinder head 33 through which the upper right stud bolt 68 is inserted among the four stud bolts 68 is used as an oil passage, and the right bearing portion 33R that supports the right end portion of the intake rocker arm shaft 57. Is formed with an oil passage 33Ra communicating the bearing hole and the bolt hole 68a (see FIG. 10).
The oil passage 33Ra communicates with an oil communication hole 57b formed at the right end portion inserted into the bearing hole of the intake rocker arm shaft 57.

  Accordingly, the oil supplied through the bolt hole 68a of the cylinder head 33 reaches the oil passage 57a in the intake rocker arm shaft 57 through the oil passage 33Ra and the oil communication hole 57b, and the upper and lower oil discharge holes 57c from the oil passage 57a. , 61c and the oil discharge holes 57d, 58d in the obliquely lower portion.

  As shown in FIG. 11, oil is injected from the oil discharge hole 61c of the collar 61 opened upward toward the contact portion with the adjusting screw 58s at the end of the valve stem 56is of the intake valve 56i, and opened downward. Oil is injected from the oil discharge hole 61c of the collar 61 toward the roller 60r of the exhaust rocker arm 60 in contact with the cam 53e of the camshaft 53.

  An oil discharge hole 57d formed obliquely downward and downward of the intake rocker arm shaft 57 supplies oil to lubrication of the rocking base end portion of the intake rocker arm 58, and at the rocking base end portion of the intake rocker arm 58. When it coincides with the formed oil discharge hole 58d at a certain swing angle, oil is injected and lubricated to the intake cam 53i of the camshaft 53 on the lower rear side.

  As described above, the main valve mechanism 50 moves the intake rocker arm 58 in the axial direction by interposing the cylindrical collar 61 inserted through the intake rocker arm shaft 57 between the left bearing portion 33L and the right bearing portion 33R. Since the cylindrical collars 62 and 63 inserted through the exhaust rocker arm shaft 59 are interposed between the left bearing portion 33L and the right bearing portion 33R, the axial movement of the exhaust rocker arm 60 is restricted. It is possible to regulate the movement of the rocker arm in the axial direction with a simple configuration that avoids an increase in size of the rocker arm and avoids the occurrence of friction.

  In the collar 61 inserted through the intake rocker arm shaft 57 having the oil passage 57a, an oil discharge hole 61c penetrating in the radial direction is formed at a predetermined position corresponding to the oil discharge hole 57c of the intake rocker arm shaft 57, and the intake rocker arm shaft 57 Since the stopper plate 65 prevents the rotation of both the collar 61 and the collar 61, a required portion of the intake rocker arm shaft 57 and the exhaust rocker arm shaft 59 (the contact portion between the adjustment screw 58s at the end of the valve stem 56is, Oil supply to the rollers 58r, 60r) of the intake rocker arm 58 and the exhaust rocker arm 60 can be easily ensured.

  The stopper plate 65 can prevent the collar 61 from rotating, and the axial movement of the intake rocker arm shaft 57 and the exhaust rocker arm shaft 59 and the rotation of the intake rocker arm shaft 57 can be restricted. Assembly work can also be simplified.

1 is an overall side view of a scooter type motorcycle according to an embodiment of the present invention. It is sectional drawing (II-II sectional view taken on the line of FIG. 1) of the front half part of a power unit. It is sectional drawing (III-III sectional view taken on the line of FIG. 1) of the front half part of a power unit. It is the right view which abbreviate | omitted one part section of the front half part of the power unit. It is the right view which removed the radiator cover of the front half part of a power unit. It is a right side (front side) side view of a shroud. It is a left side (back side) side view. It is the VIII-VIII sectional view taken on the line of FIG. It is a top view of a cylinder head. It is a front view of the cylinder head. It is a principal part enlarged view of FIG. It is the XII-XII sectional view taken on the line of FIG. It is a perspective view of an intake rocker arm shaft. It is a perspective view of a color. It is a perspective view of a stopper plate. It is explanatory drawing which shows the state in which the rocker arm shaft, the collar, and the stopper plate were assembled.

Explanation of symbols

20 ... Power unit, 30 ... Internal combustion engine, 31 ... Crank case, 32 ... Cylinder block, 33 ... Cylinder head, 33a ... Combustion chamber, 33c ... Inner wall, 33R ... Right bearing part, 33L ... Left bearing part,
50 ... Valve mechanism, 51 ... Cam chain, 52c, 52s, 52h ... Cam chain chamber, 53 ... Cam shaft, 54 ... Driven sprocket, 55 ... Drive sprocket, 56 ... Bearing, 56i ... Intake valve, 56e ... Exhaust valve, 57 ... intake rocker arm shaft, 57a ... oil passage, 57c ... oil discharge hole (oil discharge passage), 58 ... intake rocker arm, 59 ... exhaust rocker arm shaft, 60 ... exhaust rocker arm, 61, 62, 63 ... collar, 61c ... oil discharge Hole, 65 ... stopper plate, 65c ... collar engaging piece.

Claims (3)

A rocker arm (58) is pivotally supported on a rocker arm shaft (57) supported between the bearings, and one end of the rocker arm (58) is in sliding contact with a cam (53i) formed on the camshaft (53). In the valve mechanism of the internal combustion engine in which the other end is driven to open and close the valve (56i) via the adjusting screw (58s),
A cylindrical collar (61) inserted through the rocker arm shaft (57) is interposed between the bearings to restrict the movement of the rocker arm (58) in the axial direction,
A stopper plate (65) for restricting the movement of the rocker arm shaft (57) in the axial direction,
The collar engaging piece (65c) of the stopper plate (65) engages with a notch (61p) provided in the collar (61) to prevent the collar (61) from rotating. A valve mechanism for an internal combustion engine. The stopper plate (65) is engaged with a notch (57e) formed at an end of the rocker arm shaft (57) to prevent the rocker arm shaft (57) from rotating. The valve operating mechanism for an internal combustion engine according to claim 1, wherein: An oil passage (57a) is formed in the rocker arm shaft (57) in the axial direction and an oil discharge passage (57c) that penetrates in the radial direction and communicates with the outer peripheral surface is formed at a predetermined position in the axial direction.
  An oil discharge hole (61c) penetrating in a radial direction is formed in the collar (61) at a predetermined position corresponding to the oil discharge passage (57c) of the rocker arm shaft (57). 3. A valve operating mechanism for an internal combustion engine according to claim 2.

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