KR100416053B1 - Working Valve Apparatus for Overhead Valve typed Internal-Combustion Engine - Google Patents

Abstract

In an operation valve device of an overhead valve type internal combustion engine, it is possible to reduce the size and weight of a bearing of a camshaft and to reduce the size of an internal combustion engine.

The operation valve device of the overhead valve type internal combustion engine 30 is supported by a bearing, and is provided with a cam shaft 57 provided with an intake cam 75 and a boost cam 77, an intake cam follower 78 and a boost cam follower. 80, an intake rocker arm 85 and a supercharged rocker arm 87, an intake pull rod 82, and a push rod 84 are provided. The intake cam follower 78 is in contact with the intake cam 75 on the cylinder 45 side of the attachment surface B of the cylinder 45 and the cylinder head 43, and the supercharge cam follower 80 is attached to the attachment surface ( The supercharge cam 77 is in contact with the cylinder head 43 side of B).

Description

Working Valve Apparatus for Overhead Valve typed Internal-Combustion Engine}

The present invention relates to an operation valve device of an overhead valve type internal combustion engine which transfers the movement of a cam follower, which is oscillated by a cam installed on a camshaft, to a rocker arm via a rod to openly drive the engine valve.

Conventionally, as an operation valve device of an overhead valve type internal combustion engine, an intake cam and an exhaust cam are installed on a single cam shaft disposed near the crank shaft, and the open driving force of both cams is one pair of tappets and one pair of push rods. It is known that the intake valves and the exhaust valves are open-driven, respectively, to the intake and exhaust rocker arms provided in the cylinder head via the openings (see Japanese Patent Application Laid-Open No. 9-250324).

By the way, in the said prior art, when opening an intake valve and an exhaust valve, the opening load based on a valve spring and combustion chamber pressure acts centrally through a camshaft to the part of the bearing which rotatably supports a camshaft. Thus, the bearings are required to have strength and durability that can withstand their open loads, resulting in larger bearings and increased weight.

In addition, since the push rod for transmitting the cam driving force to the rocker arm extends from the vicinity of the crankshaft to the cylinder head, the rod has a large diameter to prevent buckling, and its weight has also increased. Therefore, it is necessary to secure a relatively wide space on the sides of the cylinder and the cylinder head in order to arrange the push rod, and the internal combustion engine is enlarged, and the inertia of the operation valve system from the cam to the intake valve and the exhaust valve by the push rod is increased. The mass became large, and the followability of the intake valve and the exhaust valve to the cam was reduced in the high rotation range of the internal combustion engine.

This invention is made | formed in view of such a situation, The invention of Claim 1 thru | or 3 is a common objective in the operation valve apparatus of an overhead valve-type internal combustion engine, aiming at reducing the size of the bearing of a camshaft, and the size of an internal combustion engine. It is done. Moreover, the invention of Claim 2 also aims at improving the followability of the engine valve in high rotation range.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a left side view of a scooter type motorcycle which is equipped with an overhead valve internal combustion engine having an operation valve device of the present invention.

FIG. 2 is a schematic cross-sectional view illustrating main parts when the crankcase, the cylinder, and the cylinder head are cut by the II-II line in FIG. 1. FIG.

3 is a cross-sectional view taken along the line III-III of FIG. 2.

4 is a cross-sectional view taken along the line IV-IV of FIG. 2.

5 is a cross-sectional view taken along the line VV of FIG. 4.

<Explanation of symbols for main parts of drawing>

One … Motorcycle 2. volt

3…. All frames 4... Rear frame

5... Front wheel 6. Rear wheel

7. Power unit 8... Sheet

9. All Fender 10… Cover all

11. Step floor 12... Frame body cover

13. Rear fender 14... Side cover

15... Storage box 16... Swing arm

17. Shock absorber 18. King pin

19. Axle holder 20. axle

21. Head pipe 22. Handle post

23. Steering arm 24.. link

25…. Bracket 26.. Hanger hole

27. Shock absorber 30. An internal combustion engine

31. Crankshaft 32... Air cleaner

33. Air introduction pipe 34. Throttle bodybuilder

35. Intake pipe 36. Fuel injection valve

37. Fuel tank 38. vent pipe

39. Exhaust muffler 40. Fan cover

41…. Radiator 42... Crankcase

43. Cylinder head 44.. Cylinder head cover

45.. Cylinder 46.. Tube bush

47. Piston 48.. Cone road

49, 50... Main bearing 51. Intake port

52... Exhaust port 53. Supercharged port

54. Combustion chamber 55... spark plug

56. Supercharger 57. Camshaft

58, 59... Cam holders 60, 61. bearing

62. Alternator 63. nut

64. Cooling fans 65, 66. Gear

67. Oil pump 68. Suction passage

69. Children axis 70, 71, 72. Gear

73. Intake valve 74. Supercharge valve

75... Intake cam 76... Exhaust cam

77. Supercharged cam 78. Intake Cam Follower

79. Exhaust cam follower 80. Supercharged cam follower

81... Support shaft 82... Intake pull rod

83... Exhaust pull rod 84... Push rod

85... Intake rocker arm 86. Exhaust rocker arm

87. Supercharger rocker arm 88. volt

89. Guide plates 90, 91. Valve spring

92. Rotary position sensors 93, 94. bearing

95. Cooling water pump 96. Water pipe

97. Discharge hole 98... Thermostat

99. Weight 100... Power train

101. Planetary gearbox 102. Transmission case

103. Center axis 104. Input gear

105. Oscillation clutch 106,107,108; Shift clutch

109. Output shaft 110.. Rotation fixing member

111. Flange mounting boss 112. Pinion

113, 114, 115... Gear 116. One-way clutch

117. Output gear 120... Final deceleration device

121. Drive shaft 122... Gear

123. Speed sensor A... Split plane

B… Mounting surface C0.. Body center

C1 to C6... Axis

The invention as set forth in claim 1 of the present application is a single cam shaft rotatably supported by a bearing and provided with a cam, a first cam follower and a second cam follower swinging in contact with the cam, a first engine valve, and A first rocker arm and a second rocker arm slidably installed in the cylinder head so as to open the valve respectively to the second engine valve so as to be in contact with the first and second engine valves respectively; A motion valve device for an overhead valve type internal combustion engine having a first rod and a second rod for transmitting a movement of a two cam follower to the first and second rocker arms, respectively, wherein the first and second rocker arms Is disposed on one side in the axial direction of the cylinder with respect to the plane including the axis of the cam axis, the first cam follower is in contact with the cam on the side opposite to the one side, and the second cam follower is the one side. In contact with the cam, is also a valve unit of the overhead valve type internal combustion engine, it characterized in that the first load is a full load (pull rod), and the second rod is a push rod.

According to the invention as set forth in claim 1, since the first and second cam followers are in contact with the cam on one side and the opposite side of the plane, an opening load acting on the camshaft upon opening of the first and second engine valves. Is distributed in two parts of the bearing. As a result, it is not necessary to increase the strength of the bearing as compared with the case where the open load is concentrated on one part of the bearing, so that the bearing can be made smaller and lighter.

In addition, a first cam that swings in a direction away from the first rocker arm and is located at a position far from the first rocker arm relative to the second cam follower with respect to the first and second rocker arms disposed on one side of the plane. The rod which transmits the movement of the follower to the first rocker arm is a full rod, the second cam type which is in a position closer to the second rocker arm relative to the first cam follower and oscillates in a direction closer to the second rocker arm Since the rod that transmits the eastern motion to the second rocker arm is a push rod, the shape of the cam follower and the arrangement of the rod can be simplified, and the space for disposing the cam follower and the rod can be made small, The internal combustion engine can be miniaturized.

In the invention according to claim 2, in the operation valve device of the overhead valve type internal combustion engine according to claim 1, the length of the push rod is shorter than the length of the pull rod.

According to the invention as set forth in claim 2, in order to prevent the buckling of the rod, it is not necessary to consider the buckling of the rod because the length of the push rod, which is larger in diameter, is shorter than the length of the pull rod, which is smaller in diameter, so that the weight of the rod can be reduced. Since the inertial mass of the operation valve system can be reduced, the followability of the engine valve to the cam can be improved at a high rotational range of the internal combustion engine.

The invention according to claim 3 is the operation valve device of the overhead valve type internal combustion engine according to claim 1 or 2, wherein the cam shaft is disposed on the side of the cylinder so as to offset from the cylinder, and the pull rod is Passing between the cam shaft and the cylinder is connected between the first cam follower and the first rocker arm.

According to the invention as set forth in claim 3, since the pull rod is disposed using a space formed between the cylinder and the cam shaft, the amount of protrusion to the side of the cylinder or the cylinder head can be suppressed, and the rod is compared with the push rod. By the pull rod having a small diameter, the offset amount of the cam shaft can be reduced, and the amount of protrusion of the cam shaft to the side of the cylinder or the cylinder head can be reduced, so that the internal combustion engine can be miniaturized.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described with reference to FIGS.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a left side view of a scooter type motorcycle having an overhead valve type internal combustion engine having an operating valve device of the present application. In addition, in this specification, "front, rear, left and right" means back, front, left, and right in a vehicle body. Moreover, "body center" means the vertical surface which passes the center position of the wheel mounted to the motorcycle in the left-right direction.

The motorcycle 1 has a main frame consisting of a front frame 3 and a rear frame 4 connected by bolts 2. The whole frame 3 is provided with all the suspension mechanism which suspends the front wheel 5, and the steering mechanism which steers the front wheel 5, The power which drives the rear wheel 6 behind the front of the rear frame 4 is provided. The unit 7 is provided, the rear suspension mechanism which suspends the rear wheel 6 is provided in the rear part of the rear frame 4, and the seat 8 is provided in the upper side of the rear frame 4. As shown in FIG.

The motorcycle 1 is further equipped with a front fender 9, a full cover 10, a step floor 11, a frame body cover 12, and a rear fender 13, in order from front to rear, and further, a step floor. The pair of left and right side covers 14 are provided at 11. In the frame body cover 12 under the seat 8, a storage box 15 for storing a helmet or the like is provided.

The all suspension mechanism is located on the right side of the front wheels 5, and the swing arm 16 is pivotally supported on the front lower end portion of the front frame 3 in the up and down direction, and one end is pivotally mounted to the swing arm 16. And the other end is provided with the shock absorber 17 pivotally mounted to the frame 3 at all. An axle holder 19 is pivotally attached to the front end of the swing arm 16 via a king pin 18 in a lateral direction, and the front wheel 5 is attached to the axle 20 attached to the axle holder 19. It is rotatably supported.

The steering mechanism includes a handle post 22 rotatably supported by the head pipe 21 attached to the front upper end of the frame 3, a steering arm 23 attached to the lower end of the handle post 22, and one end. A link 24 pivotally attached to the additional steering arm 23 and the other end pivotally mounted to the arm 19a of the axle holder 19 is provided. In this way, the steering mechanism and all the suspension mechanisms are designed to be independent of each other, thereby improving the maneuverability.

The whole of the power unit 7 is hanger hole 26 of the bracket 25 attached to the left and right pair of rear frame 4, respectively, and the front end part of the lower crankcase 42L of the internal combustion engine 30 mentioned later. And a pair of hanger bolts respectively inserted in the tube bush 46 (refer to FIG. 2) provided at the front end of the cylinder head 43 so as to be able to swing on the rear frame 4. On the other hand, the rear part of the power unit 7 is attached to the rear part of the rear part frame 4 on the left side via the shock absorber 27. Thereby, the power unit 7 is able to rock up and down according to the ups and downs of the road surface at the time of running.

The power unit 7 includes an internal combustion engine 30, a power transmission device 100 having a planetary gear type transmission 101 and a final deceleration device 120. The internal combustion engine 30 is an overhead valve type internal combustion engine of a 4-cycle single cylinder, and a flexible air inlet tube 33, which is connected to the air cleaner 32 disposed inside the frame body cover 12, is disposed on the right side of the vehicle body. It is connected to the upstream end of the throttle body 34 which became. An intake pipe 35 connected to an intake port 51 of the cylinder head 43 is connected to a downstream end of the throttle body 34, and a fuel injection valve 36 is attached to the intake pipe 35. . The fuel injection valve 36 is supplied with fuel from a fuel tank 37 disposed below the step floor 11. Moreover, the exhaust muffler 39 which the exhaust pipe 38 connected to the exhaust port 52 of the cylinder head 43 is connected to the right side of a vehicle body is arrange | positioned. In addition, the radiator 41 that receives the cooling wind from the cooling fan 64 (see FIG. 3) disposed in the fan cover 40 mounted at the front end of the crank case 42 has an upper portion of the crank case 42. Is placed on.

The output of the transmission 101 of the power transmission device 100 is transmitted to the axle of the rear wheel 6 by the shaft drive mechanism provided with the drive shaft 121 of the final deceleration device 120, so that the rear wheel 6 is Driven.

3, which is a sectional drawing of the III-III line | wire of FIG. 2 and FIG. 2 which is a schematic sectional drawing of the main part when the crankcase 42, the cylinder 45, and the cylinder head 43 were cut | disconnected in the II-II line | wire of FIG. The power unit 7 will be further described with reference to FIG. 4 which is a sectional view along the IV-IV line of FIG. 2, and FIG. 5 which is the sectional view along the V-V line of FIG.

The internal combustion engine 30 is comprised by the crankcase 42, the cylinder head 43, and the cylinder head cover 44 overlapping one another, and being assembled. The crankcase 42 includes the axis C1 of the crankshaft 31 of the internal combustion engine 30 and is divided into two upper and lower crankcases 42U and 42L by the divided surface A inclined with respect to the horizontal plane. The divided surface A in the lower crankcase 42L faces the upper right side of the vehicle body. At the upper part of the upper crankcase 42U, a cylinder 45 having an axis C2 inclined to the upper right side of the vehicle body with respect to the axis C1 of the crankshaft 31 is integrally formed, and the cylinder 45 The cylinder head 43 is attached to the attachment surface B which faces the upper right side.

Moreover, both crankcase 42U and 42L serve as a part of the transmission case which covers the whole of the transmission 101 of the power transmission device 100 which transmits the power of the crankshaft 31 to the rear wheel 6. As shown in FIG. Moreover, the tube bush 46 in which the hanger bolt which supports the power unit 7 is fitted in the bracket 25 of the rear frame 4 is provided in the outer end outer surface of the lower crankcase 42L. The tubular bush 46 includes a cylindrical portion 46a integrally formed on the lower crankcase 42L, an elastic member 46b formed of a cylindrical rubber or the like whose outer peripheral surface is fixed to the inner peripheral surface of the cylindrical portion 46a, and The outer circumferential surface is fixed to the inner circumferential surface of the elastic member 46b, and is composed of a metal insertion tube 46c through which the hanger bolt passes. And the tube bush 46 of the same structure is provided also in the cylinder head 43. As shown in FIG.

As for the crankshaft 31, the axis line C1 is oriented in the front-back direction of a vehicle body, so-called vertical arrangement is supported by the crankcase 42 through a pair of main bearings 49 and 50. As shown in FIG. Each of the main bearings 49 and 50 is held in a semicircular concave groove formed in each of the divided surfaces A of both crankcases 42U and 42L, and the axis line C1 of the crank shaft 31 is divided into the divided surfaces ( It is located on A).

Then, the small end is pivotally mounted to the piston pin of the piston 47 slidably fitted to the cylinder bore of the cylinder 45, and the cone rod 48 is pivotally mounted to the crank pin of the crankshaft 31. Through this, the crankshaft 31 is driven to rotate by the reciprocating piston 47.

Here, the relationship between the dividing surface A, the attachment surface B, and the axis C2 of the cylinder 45 is demonstrated in more detail. In the reference plane orthogonal to the axis C1 of the crankshaft 31 and including the axis C2 of the cylinder 45, the intersection of the dividing surface A and the reference plane and the axis of the crankshaft 31. The angle α formed by the reference vertical line, which is a vertical semi-linear line extending upward from the intersection of (C1) and the reference plane, is an acute angle. Further, the angle β formed between the axis C2 of the cylinder 45 and the reference vertical line is also acute, so that the angles α and β are approximately equal. The angle γ, which is an equiangular angle of angle α as an angle formed by the extension line of the attachment surface B, the intersection of the reference plane and the reference vertical line, is smaller than the angle α. Accordingly, the angle between the dividing surface A and the intersection of the reference plane, the attachment surface B and the intersection of the reference plane and the cylinder axis C2 is formed between the vehicle body C0 and the intersection of the reference plane. , Angle α, angle β and angle γ, respectively. In addition, the values of these angles α, β, and γ are appropriately set in consideration of the magnitude of the inclination angle to be set.

As a result, with respect to the dividing surface A and the attachment surface B inclined from the lower right to the upper left, the attachment surface B is inclined at a larger angle with respect to the horizontal plane than the dividing surface A. FIG. The plane including the dividing surface A and the plane including the attaching surface B intersect at the lower side of the cylinder 45.

In addition to the intake port 51 and the exhaust port 52, the cylinder head 43 is provided with a charging port 53 to which the exhaust air conduit of the double-acting piston-type supercharger 56 is connected. 52 and 53 are connected to the combustion chamber 54 formed in the lower surface of the cylinder head 43. As shown in FIG. The combustion chamber 54 is supplied with a mixture of fuel and air injected from the combustion injection valve 36 toward the intake port 51. An ignition plug 55 for igniting the mixer is attached to the cylinder head 43 toward the combustion chamber 54.

Further, at each rear end of the cylinder head 43 and the upper crankcase 42U, a hole formed by a semi-circumferential concave groove formed in the attachment surface B, respectively, is formed, and the supercharger 56 is formed in the hole. The supercharged cylinder 56a forming the housing of the housing is fitted.

In addition, a pair of single cam shafts 57 whose axes C3 are disposed to face the front-back direction of the vehicle body are fixed by a pair of cam holders 58 and 59 attached to the cylinder head 43, respectively. Is rotatably supported through the bearings 60 and 61 (see FIG. 3). The axis C3 of the camshaft 57 is located on the attachment surface B, which is also a plane which includes the axis C3 and is orthogonal to the axis C2 of the cylinder 45, and the camshaft 57 itself. Is arranged on the side of the cylinder 45 so as to offset from the cylinder 45, that is, the axis C3 of the cam shaft 57 does not intersect the cylinder 45.

As shown in FIG. 3, the alternator 62 is provided in the front end part located ahead of the main bearing 49 of the front side of the crankshaft 31, and the rotor 62a of the alternator 62 is The crankshaft 31 is fixed to the crankshaft 31 by the nut 63 of the front end part of the crankshaft 31. Moreover, the cooling fan 64 which sends cooling air to the radiator 41 is attached to the rotor 62a of the alternator 62 with a bolt.

On the other hand, behind the main bearing 50 at the rear of the crankshaft 31, the first drive gear 65 and the second drive gear 66 are rotated integrally with the crankshaft 31 in order toward the rear, respectively. Attached. In addition, a fitting hole coaxial with the crank shaft 31 is formed in the rear end face of the crank shaft 31, and the driving shaft 67a of the hollow wheel pump 67 is fitted in the fitting hole, and the crank shaft 31 and It is made to rotate integrally.

The oil stored at the bottom of the lower crankcase 42L is sucked into the oil pump 67 via the suction passage 68 formed in the transmission case 102, and the oil discharged from the oil pump 67 is crankcase 42. And a cam shaft 57, a center shaft 103 of the transmission 101, and respective bearings, respectively, via a flow path and an oil pipe provided in the transmission case 102. The main bearings 49 and 50 of the crankshaft 31 and the slide portions between the crank pins and the large ends of the cone rod 48 are discharged through the inside of the drive shaft 67a of the oil pump 67. Oil is supplied.

The first drive gear 65 meshes with the counter gear 70 attached to rotate integrally with the idle shaft 69. Since the idle shaft 69 also serves as a balancer shaft as will be described later, the number of teeth of the standby gear 70 is the number of teeth of the first drive gear 65 so as to rotate at the same rotation speed as the crank shaft 31. Is equivalent to Moreover, in order to rotate-drive the camshaft 57, the small gear 71 which meshes with the cam gear 72 provided so that it may rotate integrally with the camshaft 57 is provided in the large gear 70 integrally. Then, by the series of gear trains 65, 70, 71, 72, the cam shaft 57 rotates once each time the crank shaft 31 rotates two times.

The cam gear 72 is splined to the boost crankshaft 56c which reciprocates the boost piston 56b of the double acting piston type turbocharger 56. As shown in FIG. The camshaft 57 is provided with the hollow part which becomes a flow path which supplies oil to the cam mentioned later and the slide part of each rocker arm, and the extension part of the supercharge crankshaft 56c is provided in the edge part of the turbocharger 56 side of this hollow part. It is press-fitted. Thereby, the camshaft 57 rotates integrally with the supercharge crankshaft 56c.

The operation valve apparatus is provided with the cam, cam follower, pull rod, push rod, and rocker arm demonstrated below. As shown in Figs. 2 and 4, the cam shaft 57 has an intake cam 75 for opening and driving three engine valves, an intake valve 73, an exhaust valve (not shown), and a boost valve 74, respectively. ), The exhaust cam 76 and the boosting cam 77 located between the two cams 75 and 76 are provided at intervals in the direction of the axis C3 of the cam shaft 57.

The intake rocker arm 85, the exhaust rocker arm 86 and the supercharger rocker arm 87 are cylinders on the cylinder head 43 side which is one side in the axis C2 direction of the cylinder 45 of the attachment surface B. It is provided so that the head 43 can oscillate, and can contact the intake valve 73, the exhaust valve, and the boost valve 74, respectively.

Supercharging located between the intake cam follower 78, the exhaust cam follower 79, and both cam followers 78, 79 in contact with the intake cam 75, the exhaust cam 76, and the boost cam 77, respectively. Cylindrical supports 78a, 79a, 80a are formed at the proximal end of the cam follower 80, and both cam holders 58, 59, and the cylinder are mounted on the attachment surface B at each support 78a, 79a, 80a. The cam shafts 78, 79, and 80 are swingably supported with respect to the support shaft 81 by inserting the support shaft 81 which is inserted into the semi-circular concave groove formed in the head 43 and fixed. . 5 shows a concave groove 58a formed in the cam holder 58 and a concave groove 43a formed in the cylinder head 43 corresponding to the concave groove 58a. The support shaft 81 has an axis parallel to the axis C3 of the cam shaft 57, and the cam shaft 57 with respect to the axis C1 of the cylinder 31 on the attachment surface B. As shown in FIG. It is located below the camshaft 57 as a position farther apart.

Further, at the distal end of the intake cam follower 78, a locking portion 78b is formed, on which one end of the intake pull rod 82 is caught. And the contact part 78c which contacts the intake cam 75 is formed between the support part 78a of the intake cam follower 78, and the engaging part 78b. Similarly to the intake cam follower 78, the exhaust cam follower 79 is also provided with a catching portion 79b at which one end of the exhaust pull rod 83 is caught at the front end portion 79b, and the catching portion 79a and the supporting portion. Between 79b, the contact part which contacts the exhaust cam 76 is formed. Then, the engaging portion 78b and the contact portion 78c of the intake cam follower 78, and the engaging portion 79b and the contact portion of the exhaust cam follower 79 are both cylinder 45 with respect to the attachment surface B. It is located on the cylinder 45 side which is the other side which becomes an opposite side with respect to the said one side of the axis line C2 direction of the.

On the other hand, the booster cam follower 80 is provided with a support portion 80b in contact with the push rod 84 and a contact portion 80c in contact with the booster cam 77 at its distal end. And the support part 80b and the contact part 80c are located in the cylinder head 43 side which is one side of the axis line C2 direction of the cylinder 45 with respect to the attachment surface B. As shown in FIG.

In addition, the intake pull rod 82 is connected between the intake cam follower 78 and the intake rocker arm 85 through a space formed between the cam shaft 57 and the cylinder 45, and the exhaust pull is similarly used. The rod 83 is connected between the exhaust cam follower 79 and the exhaust rocker arm 86 through a space formed between the cam shaft 57 and the cylinder 45.

The push rod 84 penetrates the guide hole formed in the guide plate 89 fixed to the cylinder head 43 by the bolt 88 which swivelably supports the supercharger rocker arm 87, and the push rod 84 Can move stably in the axial direction.

In addition, since the diameter of the push rod 84 needs to prevent buckling of the rod, the diameter of the push rod 84 is larger than the diameter of both pull rods 82 and 83. In addition, the length of the push rod 84 is shorter than the length of both the pull rods 82 and 83.

By such an operation valve device, the intake valve 73 is moved by the intake rocker arm 85 that swings in the intake pull rod 83 pulled down by the intake cam follower 78 swinging in contact with the intake cam 75. In response to the elastic force of the valve spring 90, it is driven to open.

In the same way as the intake valve 73, the exhaust valve is also controlled by the exhaust rocker arm 86 swinging on the exhaust pull rod 83 pulled down by the exhaust cam follower 79 swinging in contact with the exhaust cam 76. It is open driven against the elastic force of the spring (not shown).

In addition, the boost valve 74 is a valve spring 91 by the boost rocker arm 87 swinging on the push rod 84 pushed up by the boost cam follower 80 swinging in contact with the boost cam 77. It is open to resist elastic force. And the boost valve 74 is opened when the internal combustion engine 30 is in a compression stroke.

The cylinder head 43 is also equipped with a rotation position sensor 92 for detecting the rotational position of the cam shaft 57 by a rotating plate fixed to the front end of the cam shaft 57. As a result, the engine stroke state required for fuel injection timing control is detected.

By the way, the idle axis 69 which the axis line C4 is arrange | positioned toward the front-back direction of a vehicle body is formed in cylindrical shape, and is provided with the large cylindrical part 69b and the small cylindrical part 69b. The large cylindrical portion 69a and the small cylindrical portion 69b are rotatably supported by a pair of bearings 93 and 94 held by both crankcases 42U and 42L, respectively. Each bearing 93, 94 is held in a semi-circular concave groove formed in each of the divided surfaces A of both crankcases 42U and 42L, similarly to the main bearings 49 and 50 of the crankshaft 31. The axis C4 of the idle shaft 69 is located on the dividing surface A. As shown in FIG.

And inside the large cylindrical part 69a, the housing 95a of the coolant pump 95 is accommodated in the radial direction from the inner peripheral surface of the large cylindrical part 69a. A cover 95b of the cooling water pump 95 is attached to the housing 95a in a liquid sealed state, and a water pipe 96 from the outlet side tank of the radiator 41 is connected to the cover 95b. In addition, the cylinder 45 is formed with a discharge hole 97 (see FIG. 2) in communication with the discharge portion of the cooling water pump 95 and in communication with the cooling water jacket formed around the cylinder bore.

In the pump chamber formed by the housing 95a and the cover 95b, the inside of the pump chamber extends in the axial direction, and one end thereof is rotatably supported at the bottom of the housing 95a by the other end of the cover 95b. The rotating shaft 95c is provided. The cooling water pump 95 is provided with the impeller 95d integrally attached to the rotating shaft 95c, and the permanent magnet 95e is attached to the circumferential direction of the axial part of the said impeller 95d. In the interval between the inner circumferential surface of the large cylindrical portion 69a of the idle shaft 69 and the housing 95a, the inner circumferential surface of the large cylindrical portion 69a is spaced with a slight gap between the housing 95a. The permanent magnet 95f is attached in the direction, and magnetic coupling is formed between the permanent magnet 95e of the shaft part of the impeller 95d.

The radiator 41 is disposed between the upper crankcase 42U and the V-shape formed by the cylinder head 43, and both left and right ends thereof are fixed to the upper crankcase 42U and the cylinder head 43, respectively. .

Therefore, when the idle shaft 69 rotates, the impeller 95d rotates through this magnetic coupling, and the coolant flowing into the pump chamber via the water pipe 96 becomes high pressure by the impeller 95d, and the discharge chamber 97 It is pressurized into the coolant jacket via).

The cooling water which has finished cooling the hot parts of the cylinder 45 and the cylinder head 43 is the inlet tank of the radiator 41 through the thermostat 98 from the cooling water outlet of the cylinder head 43, as shown in FIG. 2. Flows into. By using the V-shaped space formed by the upper crankcase 42U and the cylinder head 43 in this way, the radiator 41 can be arranged compactly here, and the power unit 7 can be miniaturized.

In addition, a cylindrical weight 99 having an opening is attached to an outer circumferential surface of the large cylindrical portion 69a of the idle shaft 69, which is generated by the rotation of the crank shaft 31 provided with the balance weight. The balancer which suppresses vibration and the vibration which arises by the reciprocating movement of the piston 47 and the cone rod 48 is formed.

Accordingly, the idle shaft 69 is a drive shaft for driving the coolant pump 95 and also serves as a balancer shaft as described above. Thus, by making the idle shaft 69 provided in the drive mechanism which drives the cam shaft 57 into a coaxial biaxial rotary shaft, it can also function as the drive shaft and balancer shaft of the coolant pump 95. FIG. As a result, the cost can be reduced as compared with the case where a rotating shaft having these functions is provided separately from the idle shaft.

By the way, the cam shaft 57 and the idle shaft 69 are the sides where the plane including the dividing surface A and the plane containing the attachment surface B intersect with respect to the axis C2 of the cylinder 45, That is, the dividing surface A and the attachment surface B are arrange | positioned on the side which mutually approaches. Thus, the idle shaft 69 supported on the divided surface A and the cam shaft 57 supported on the attachment surface B can be disposed in close proximity to each other, so that the idle shaft 69 and the cam shaft 57 are disposed. Both rotary shafts 57 and 69 can be directly coupled by the small gear 71 and the cam gear 72 without interposing another intermediate shaft and increasing the small gear 71 and the cam gear 72. have. As a result, the length in the direction of the axis C2 of the cylinder 45 of the internal combustion engine can be suppressed, and the protruding dimension in the left direction of the internal combustion engine 30 becomes smaller, and the power unit 7 becomes smaller.

Further, the idle shaft 69 which is a coaxial biaxial rotary shaft having a plurality of functions with the cam shaft 57 in a narrow space surrounded by the dividing surface A and the attachment surface B on the intersecting side of the cylinder 45. Since it is arranged intensively, a wide space without a rotating shaft can be formed in the side surface of the cylinder 45 on the opposite side, and peripheral components can be arrange | positioned in the space.

On the other hand, the planetary gear transmission 101, which is a component of the power transmission device 100, has a center shaft 103, an input gear 104, an oscillation clutch 105, and a respective transmission clutch for two speeds, three speeds, and four speeds. (106, 107, 108) and the output shaft 109 are provided. The center shaft 103 is not rotatable by the rotation fixing member 110 covering the shaft end attached to the case of the final deceleration device 120.

Hereinafter, the operation of the transmission 101 will be described.

The second drive gear 66 of the crankshaft 31 is engaged with the input gear 104 attached to the flange provided in the axial center portion of the flanged boss 111 that is rotatable to the center shaft 103. The rear portion of the flanged boss 111 is engaged to rotate integrally with the clutch inner 105a of the oscillation clutch 105, and all of them fit with the small gear 114 of the idle shaft constituting the deceleration mechanism of the starting motor. A pulsating starting driven gear 115 is attached via the one-way clutch 116. At the start, the starter motor rotates with the pinion 112, the idle gear 113, the idle gear 114, the starting gear 115, the one-way clutch 116, the input gear 104, and the like. It is transmitted to the crankshaft 31 via the second drive gear 66.

The oscillation clutch 105 is provided coaxially with the center shaft 103, has a clutch inner 105a, an outer clutch 105b, and a centrifugal weight 105c, and when the clutch inner 105a reaches a predetermined rotational speed. By the operation of the centrifugal weight 105c, the clutch inner 105a and the outer clutch 105b are connected and both rotate integrally, so that the oscillation clutch 105 is in a fully connected state.

Moreover, each transmission clutch 106, 107, 108 has a planetary gear mechanism and a clutch mechanism. The clutch outer of the clutch mechanism is integrally engaged with the inner tooth gear of the planetary gear mechanism, and the clutch inner of the clutch mechanism is integrally engaged with the carrier for pivotally supporting the planetary gear of the planetary gear mechanism. Further, the carrier has a centrifugal weight that integrates the clutch outer and the clutch inner through a plurality of clutches when the rotation speed reaches a predetermined rotation speed. The sun gear is also attached to the center shaft 103 via a one-way clutch.

The clutch outer portion 105b of the oscillation clutch 105 is integrally coupled with the clutch outer portion 106a of the two speed transmission clutch 106, and the carrier 106b of the two speed transmission clutch 106 is the three speed transmission clutch 107. Is integrally coupled with the clutch outer 107a. Similarly, the carrier of the three-speed transmission clutch 107 is integrally coupled to the clutch outer of the four-speed transmission clutch 108, and the carrier of the four-speed transmission clutch 108 is integrally connected to the output shaft 109, respectively.

In the two-speed transmission clutch 106, the clutch mechanism is operated so that the one-way clutch 106d is reached until the inner gear gear, which is also the clutch outer 106a, and the carrier 106b, which is also the clutch inner, reach a predetermined rotational speed. Because of the sun gear 106c which does not rotate by), the carrier 106b rotates at a predetermined reduction ratio, and the clutch outer 107a of the three-speed transmission clutch 107 rotates at a reduced speed. Similarly, the clutch outer of the four-speed transmission clutch 108 is rotated at the predetermined reduction ratio by the deceleration action of the three-speed transmission clutch 107, and the output shaft is rotated at the predetermined reduction ratio by the deceleration action of the four-speed transmission clutch 108. The maximum reduction ratio is obtained by rotating 109.

Subsequently, in the two-speed transmission clutch 106, when the rotation speed of the carrier 106b reaches a predetermined rotation speed and the clutch mechanism is operated to integrate the inner tooth gear and the carrier 106b, the entire two-speed transmission clutch 106 is integrated. Until the carrier of the three-speed transmission clutch 107 reaches a predetermined rotation speed, the carrier rotates at a predetermined reduction ratio, and the clutch of the four-speed transmission clutch 108 is decelerated at a reduced speed. The outer rotates. Further, a smaller reduction ratio is obtained by rotating the output shaft 109 at a predetermined reduction ratio by the deceleration action of the four-speed transmission clutch 108.

Similarly, when the 3-speed transmission clutch 107 rotates integrally without the deceleration action by the operation of the clutch mechanism, the output shaft 109 rotates at a predetermined reduction ratio by the deceleration action of the 4-speed transmission clutch 108. Thus, a smaller reduction ratio is obtained. When the four-speed transmission clutch 108 rotates integrally without the deceleration action by the operation of the clutch mechanism, the clutch inner 105a and the output shaft 109 of the oscillation clutch 105 are directly connected to each other. The output shaft 109 is rotated at the same rotational speed as the clutch inner 105a.

In addition, these predetermined rotation speeds have a different value, respectively, and are set suitably in consideration of a shift characteristic.

The output of the transmission 101 thus operated is transmitted to the rear wheels 6 by the shaft drive mechanism. That is, the output gear 117 attached to the output shaft 109 of the transmission 101 meshes with the gear 122 fixed to the drive shaft 121 of the final deceleration device 120. In the drive shaft 121 which is located at the center of the vehicle body C0 relative to the center shaft 103, and whose axis C6 is arranged to face the front-back direction of the vehicle body, the rear end thereof has a bevel gear formed therein. This bevel gear meshes with a driven bevel gear attached to the axle of the rear wheel 6. As a result, the rotation of the output shaft 109 is decelerated to drive the rear wheels 6.

In addition, for the control of the internal combustion engine 30, the rotation speed sensor 123 for detecting the rotation signal of the drive shaft 121 is attached to the case of the final deceleration device 120, by the sensor 123 The rotation speed of the output shaft 109 of the transmission 101 is detected.

Since this embodiment is comprised as mentioned above, the following effects are exhibited.

The intake cam follower 78 and the exhaust cam follower 79 abut on the intake cam 75 and the exhaust cam 76 on the cylinder 45 side of the attachment surface B, respectively, while the supercharge cam follower ( Since 80 is in contact with the boost cam 77 on the cylinder head 43 side of the attachment surface, the opening acting on the cam shaft 57 at the time of opening of the intake valve 73, the exhaust valve and the boost valve 74. The load is distributed on two parts of the bearings 60, 61. As a result, it is not necessary to increase the strength of the bearings 60 and 61 as compared with the case where the open load is concentrated in one part of the bearing, so that the bearings 60 and 61 can be reduced in size and weight.

For the intake, exhaust and supercharge rocker arms 85, 86, 87 disposed on the cylinder head 43 side of the attachment surface B, the intake and exhaust rocker arms 85, 86 compared with the supercharged cam follower 80 ) Moves the intake and exhaust cam followers 78, 79, which are swinging away from the intake and exhaust rocker arms 85, 86, to the intake and exhaust rocker arms 85, 86, respectively. The rods to be referred to are the intake and exhaust pull rods 82 and 83, which are closer to the supercharged rocker arm 87 than the intake and exhaust cam followers 78 and 79, and are closer to the supercharged rocker arm 87. Each cam type for oscillating each rocker arm 85, 86, 87 by the rod rod 84 transmitting the movement of the boost cam follower 80 swinging to the booster rocker arm 87 is a push rod 84. The shape of the eastern portions 78, 79, 80 and the placement of the rods 82, 83, 84 can be simplified to place the cam followers 85, 86, 87 and the rods 82, 83, 84. S Since the face can also be made small, the internal combustion engine 30 can be miniaturized.

Opening of the cam by shortening the length of the push rod 84 having a large diameter to prevent the buckling of the rod from the length of the intake and exhaust pull rods 82 and 83 having a smaller diameter because the rod buckling need not be considered. Since the load transmitting the driving force can be reduced, and the inertial mass of the operation valve system can be reduced, the intake valve 73 and exhaust for each cam 75, 76, 77 in the high rotation range of the internal combustion engine 30 can be reduced. The valve and the boost valve 74 can improve the followability.

Moreover, since the axis line C3 of the camshaft 57 is located on the attachment surface B, compared with the said prior art, the length of the push rod 84 and the pull rods 82 and 83 can be shortened, and these Since the space for arranging the rods 82, 83, 84 may be small, and the inertial mass of the operation valve system can be reduced, the cams 75, 76, 77 for the respective cams 75, 76, 77 at a high rotational range of the internal combustion engine 30 are provided. The followability of the intake valve 73 and the exhaust valve and the boost valve 74 is further improved.

Since the intake and exhaust pull rods 82 and 83 are arranged using a space formed between the cylinder 45 and the cam shaft 57, the amount of protrusion to the side of the cylinder 45 or the cylinder head 43 can be suppressed. In addition, since both pull rods 82 and 83 are rods having a smaller diameter than the push rods 84, the offset amount from the cylinder 45 of the cam shaft 57 can be reduced, and the cam shaft Since the protrusion amount toward the side of the cylinder 45 or the cylinder head 43 of the 57 can be reduced, the internal combustion engine 30 can be downsized.

Since the camshaft 57 is attached by the attachment surface B of the cylinder 45 and the cylinder head 43, the adhesiveness improves.

In the above embodiment, the plane orthogonal to the axis C2 of the cylinder 45, including the axis C3 of the camshaft 57, was the attachment surface B, but the plane orthogonal to this cylinder is the cylinder 45 or the crankcase. Surfaces other than the attachment surface B, such as the surface located in (42), may be sufficient.

In the above embodiment, the rocker arm 87 is rocked by the push rod 84, but any one of the rocker arms other than the supercharger rocker 87, for example, the intake rocker arm or the exhaust rocker arm, may be used. Also, an internal combustion engine without a boost valve may be used, in which case a push rod is used to swing either the intake rocker arm or the exhaust rocker arm. In these cases, one of the contact portion 78c of the intake cam follower 78 and the contact portion of the exhaust cam follower 79 is located on one side of the orthogonal plane, and the other is located on the other side of the plane. Done.

As the cam shaft, in addition to the intake cam and the exhaust cam, a common cam for swinging the intake cam follower and the exhaust cam follower may be used. Also in this case, one of the contact portion 78c of the intake cam follower 78 and the contact portion of the exhaust cam follower 79 is located on one side of the orthogonal plane, and the other is located on the other side of the plane. Done.

Moreover, in the said embodiment, the plane which divides the arrangement of the contact part 78c of the intake cam follower 78 and the contact part of the exhaust cam follower 79, and the contact part 80c of the supercharged cam follower 80 is a cylinder ( Although it was a plane orthogonal to the axis C2 of 45, the plane including the axis C3 of the cam axis 57 and a plane crossing the axis C2 of the cylinder 45 may be a plane other than the plane orthogonal to each other. .

Claims (3)

A single cam shaft rotatably supported by a bearing and provided with a cam, a first cam follower and a second cam follower swinging in contact with the cam, and a first engine valve and a second engine valve are respectively driven to open the valve. The first rocker arm and the second rocker arm, which are slidably installed in the cylinder head and are in contact with the first and second engine valves, respectively, and the first and second cam followers move the first and second cam followers. And an actuating valve device of an overhead valve type internal combustion engine having a first rod and a second rod, each of which is transmitted to a second rocker arm, The cam shaft is disposed laterally from the cylinder so as to offset from the cylinder, and the first and second rocker arms are disposed on the cylinder head side which is one side in the axial direction of the cylinder with respect to a plane including the axis of the cam shaft, A first cam follower is in contact with the cam on the side opposite to the one side, the second cam follower is in contact with the cam on the one side, and the first rod is a full rod and the second rod is a push An operating valve device for an overhead valve type internal combustion engine, characterized in that it is a rod. The operation valve device of an overhead valve type internal combustion engine according to claim 1, wherein a length of the push rod is shorter than a length of the pull rod. 3. The cam cam according to claim 1 or 2, wherein the cam shaft is disposed laterally of the cylinder so as to offset from the cylinder, and the pull rod passes between the cam shaft and the cylinder. An operation valve device for an overhead valve type internal combustion engine, which is connected between rocker arms.