WO2006038370A1

WO2006038370A1 - Variable valve drive device, engine, and two-wheeled motor vehicle

Info

Publication number: WO2006038370A1
Application number: PCT/JP2005/014089
Authority: WO
Inventors: Naoki Tsuchida
Original assignee: Yamaha Hatsudoki Kabushiki Kaisha
Priority date: 2004-09-30
Filing date: 2005-08-02
Publication date: 2006-04-13
Also published as: JP2008002269A

Abstract

A cam sprocket (211) is rotatingly driven by drive force transmitted from a crankshaft (130). An eccentric plate (250) is rotated, by the rotation of the cam sprocket (211), about a shaft in the same direction as the rotating shaft of the cam sprocket (211), and the shaft of the eccentric plate is moved, by a control section (150) through an eccentric boss (260), from the position of the axis of the rotating shaft to an eccentric position. When the eccentric plate (250) is rotated at the eccentric position, a rotational phase difference, relative to the cam sprocket (211), of a variable camshaft (230) and a suction cam piece (240) is periodically varied. At the maximum speed or at a speed near the maximum speed of the crankshaft (130), the control section (150) causes the position of the shaft of the eccentric plate (250) to be aligned with the position of the axis of the rotating shaft.

Description

Specification

Variable valve drive, engine and motorcycle

Technical field

[0001] The present invention relates to a variable valve drive device, an engine, and a motorcycle provided in an engine.

Background art

[0002] Conventionally, in a four-cycle engine, the period during which the intake valve and the exhaust valve are simultaneously opened (valve overlap) is changed at each of high engine speed and low / medium engine speed. High output and low fuel consumption, as well as reduction of exhaust gas.

[0003] A variable valve timing mechanism (variable valve driving device) is known as a mechanism for changing the noble overlap. This variable valve timing mechanism includes a coupling (eccentric member) that is provided between a cam drive shaft portion that interlocks with the crank drive and a cam shaft portion that drives the cam by rotating, and causes angular velocity fluctuations. The

[0004] In such a variable valve timing mechanism, the cam working angle (Duration) is controlled by periodically varying the reduction ratio of the cam angle with respect to the crank angle via the coupling and controlling the fluctuation. : Also called “operating angle”). The variable valve timing mechanism changes the valve overlap by making the working angle of the force variable.

[0005] For example, in Patent Document 1, a cam drive shaft that synchronizes with a crank rotational drive at a predetermined rotational speed is inserted into a cam and a disc-shaped eccentric plate (eccentric member) and provided on the cam drive shaft. A pin is loosely fitted in a groove extending radially in the eccentric plate. Then, due to the rotation of the force drive shaft, the eccentric plate rotates while being eccentric with respect to the cam drive shaft via the pin and the groove, thereby rotating the cam.

[0006] Further, in Patent Document 2, an eccentric plate, which is an eccentric member, is disposed between a sprocket that rotates by a driving force of a crankshaft transmitted via a gear train and a camshaft that is provided integrally with the cam. Has been placed. This eccentric plate is halfway across the center of rotation of the camshaft. Grooves extending in the radial direction are formed. In each of these grooves, a pin provided on the camshaft and a pin provided on the sprocket are slidably fitted freely, and the driving force of the cam drive shaft via the eccentric plate configured in this way is Has been communicated to.

[0007] In the configurations of Patent Documents 1 and 2, the eccentric center moves around the cam drive shaft or the cam shaft by the movement of the eccentric plate which is an eccentric member. In other words, in Patent Documents 1 and 2, the operating angle of the force that makes the center of eccentricity concentric with the cam drive shaft or the center of the cam shaft is variable, and the angular velocity of the cam is periodically varied to create a valve overlap. The amount has changed.

[0008] Further, in Patent Document 3, an annular disk as an eccentric member is arranged in a disk housing, and the center force of the cam drive shaft is decentered through the disk housing to change the angular velocity of the camshaft. By doing so, the operating angle of the intake valve is variably controlled. Note that the center of rotation of the annular disk that is eccentric by the disk housing is located outside the annular disk and substantially parallel to the center of the annular disk. In Patent Document 3, the amount of eccentricity is increased in order to widen the cam operating angle, particularly when the engine shifts to a high speed and high load range.

Patent Document 1: Japanese Patent Publication No. 47-020654

Patent Document 2: JP-A-3-43611

Patent Document 3: Japanese Patent Application Laid-Open No. 6-2515 Incidentally, along with the fluctuation of the angular acceleration of the cam, the acceleration at the time of opening and closing of the valve driven by the cam inevitably varies.

[0009] In the configurations of Patent Documents 1 to 3, the cam angular velocity is periodically varied by decentering the eccentric center of the cam drive shaft or the central force of the cam shaft, so the valve corresponds to the amount of eccentricity. The acceleration (acceleration curve) of fluctuates. When this acceleration fluctuation is large, the following problems occur.

[0010] For example, when changing the valve overlap by changing the closing timing largely by fixing the opening timing of a predetermined valve (for example, intake valve) substantially, the opening timing side is changed. Maximum acceleration and minimum acceleration are gradually increasing acceleration curves. In other words, the change due to the angular velocity fluctuation of the acceleration curve becomes large, and the acceleration curve is distorted on the open side and the close side. On the other hand, the closing side timing is substantially fixed. Similarly, when the timing is greatly changed, the maximum acceleration and the minimum acceleration increase gradually, and the acceleration curve is often distorted on the opening and closing sides of the variable valve timing.

[0011] Such distortion of the acceleration curve causes a large fluctuation range of the inertial force, causes vibration, and deteriorates the stability of engine driving.

[0012] In addition, in a valve that opens and closes, due to an increase in negative acceleration that causes distortion of the acceleration curve, a jumping phenomenon in which the valve motion deviates from the cam regulation, or a bouncing bounce when the valve sits on the valve seat ring. Valve behavior such as a phenomenon is likely to occur. This kind of valve behavior (valve behavior) further increases the vibration that occurs when the engine is running at high speed, that is, when the inertial force is large, or immediately increases in proportion to the increase of the inertial force. It will reduce engine performance.

[0013] On the other hand, Patent Documents 1 to 3 all have an eccentric center that is eccentric to the cam drive shaft or the center force of the cam shaft in order to widen the cam operating angle at high engine speeds. Changes due to fluctuations in the angular velocity of the valve acceleration proportional to the amount of eccentricity during rotation are not taken into account.

[0014] In particular, in Patent Document 3, since the shaft is greatly decentered at the time of high engine rotation, there is a possibility that vibration is generated and the stable operation cannot be performed in the valve opening / closing operation at the time of high engine rotation.

[0015] The present invention has been made in view of the points to be applied, and kinematically, large vibrations are generated due to inertial forces, and valve behavior problems such as jumping phenomenon and bounce phenomenon easily occur. An object of the present invention is to provide a variable valve drive device, an engine and a motorcycle that can reduce vibration and perform valve behavior stably at a high engine speed. Disclosure of the invention

[0016] The variable valve drive device according to the present invention includes a cam drive member that is rotated by a drive force that is transmitted with a crankshaft force, and a shaft that is in the same direction as the rotation shaft of the cam drive member by driving the cam drive member. And an eccentric member provided so that the shaft is movable from an axial center position of the rotating shaft to an eccentric position, and is disposed coaxially with the rotating shaft, and is rotated about the rotating shaft by the eccentric member. And the eccentric member is When rotationally driven at the center position, the camshaft in which the rotational phase difference with respect to the cam drive member periodically changes, and the camshaft rotates with the same rotational phase as the camshaft, and the exhaust valve or the intake valve A variable valve driving device including a cam piece for opening and closing the rotation of the crankshaft, wherein the rotational speed detection unit detects the rotational speed of the crankshaft, and the rotational speed of the crankshaft detected by the rotational speed detection unit. A controller that moves the eccentric member to control the position of the shaft of the eccentric member with respect to the rotation shaft of the cam drive member, and the control unit includes a maximum rotational speed of the crankshaft or the A configuration is adopted in which the eccentric member is moved at a rotational speed near the maximum rotational speed so that the position of the shaft of the eccentric member coincides with the axial position of the rotational shaft.

[0017] Further, the variable valve driving device of the present invention includes a cam driving member that rotates by a driving force transmitted by a crankshaft force, and the same direction as the rotating shaft of the cam driving member by driving the cam driving member. An eccentric member provided so as to be movable from an axial center position of the rotating shaft to an eccentric position, and coaxially arranged with the rotating shaft, and the rotating shaft is arranged by the eccentric member. And a cam shaft in which a rotational phase difference with respect to the cam drive member periodically varies when the eccentric member is rotationally driven at the eccentric position, and the cam shaft is the same as the cam shaft. A variable valve drive device comprising a cam piece that rotates at a rotational phase and makes the working angle of the exhaust valve or intake valve variable; a rotational speed detector that detects the rotational speed of the crankshaft; and the rotational speed Inspection A controller that controls the position of the shaft of the eccentric member with respect to the rotational shaft of the cam drive member by moving the eccentric member according to the rotation speed of the crankshaft detected by the protruding portion; The control unit force adopts a configuration in which the operating angle of the exhaust valve or the intake valve is maximized when the position of the shaft of the eccentric member coincides with the position of the shaft center of the rotating shaft.

[0018] Further, the variable valve drive device of the present invention includes a cam drive member that rotates by a drive force transmitted by a crankshaft force, and the same direction as the rotation shaft of the cam drive member by driving the cam drive member. An eccentric member provided so as to be movable from an axial center position of the rotating shaft to an eccentric position, and coaxially arranged with the rotating shaft, and the rotating shaft is arranged by the eccentric member. When the eccentric member is rotationally driven at the eccentric position, a rotational phase difference with respect to the cam drive member is a period. A variable valve drive device comprising: a camshaft that fluctuates automatically; and a cam piece that is rotated by the camshaft in the same rotational phase as the camshaft and that changes a working angle of an exhaust valve or an intake valve. A rotational speed detector for detecting the rotational speed of the crankshaft, and the eccentric member is moved in accordance with the rotational speed of the crankshaft detected by the rotational speed detector to A control unit that controls the position of the shaft of the eccentric member, and the control unit matches the position of the shaft of the eccentric member with the axial center position of the rotation shaft at a substantially maximum rotational speed of the crankshaft. In this case, the exhaust valve or the intake valve has a maximum working angle.

Brief Description of Drawings

FIG. 1 is an exploded perspective view of a main part of an engine provided with a variable valve drive device according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of an essential part showing the variable valve driving device.

FIG. 3 is an exploded perspective view of the variable valve drive device.

FIG. 4 is an exploded perspective view of an eccentric boss.

FIG. 5 is a diagram showing a positional relationship among the rotation center of the eccentric boss, the axis of the variable cam drive shaft, and the axis of the eccentric plate.

FIG. 6 is a schematic diagram illustrating a control unit of an engine provided with the variable valve drive device.

FIG. 7 is a diagram showing an example of the positional relationship between the drive pin and the driven pin in a state where the center of the eccentric plate is eccentric with respect to the cam shaft in the variable valve drive device according to one embodiment of the present invention.

FIG. 8 is a diagram showing a working angle of a nozzle corresponding to an engine speed in an engine provided with a variable valve drive device according to an embodiment of the present invention.

FIG. 9 is a diagram for explaining a variable state of a valve by a variable valve driving device according to an embodiment of the present invention.

FIG. 10 is a view for explaining a modification of the variable state of the valve by the variable valve driving device according to the embodiment of the present invention.

FIG. 11 is a schematic cross-sectional side view showing a configuration of a main part of a motorcycle including the engine drive mechanism according to the embodiment of the present invention. 12 is a schematic plan view showing a main part of the drive unit in FIG.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is an exploded perspective view of a main part of an engine provided with a variable valve drive apparatus according to an embodiment of the present invention.

The engine 100 shown in FIG. 1 is housed in an engine body 110 having a cylinder portion 106 and a cylinder head 104 that house a piston 102 so as to be able to advance and retreat, and a crankcase 112 (see FIGS. 6 and 11). It has a crankshaft 130 and a variable valve drive device 200.

[0023] It should be noted that the engine 100 provides a periodic phase difference between the rotation of the exhaust cam piece 220 and the intake cam piece 240 by the variable valve drive device 200 disposed substantially parallel to the crankshaft 130, and each rotation The timing of opening and closing corresponding to is variable. As a result, the valve overlap time is variable corresponding to the engine speed.

In the present embodiment, engine 100 will be described as a single-cylinder SOHC (Single Over Head Camshaft) type mounted on starter type motorcycle 500 (see FIG. 11). Note that the engine 100 is not limited to the force described as a single-cylinder SOHC type, and may be any engine as long as it has the variable valve driving device 200. In general, the maximum engine speed mounted on a motorcycle is 8000 rpm or more. Here, since the maximum rotation speed obtains a stable output continuously, for example, about 10% overspeed is considered, but instantaneous overspeed is not intended.

As shown in FIG. 1, the piston 102 in the cylinder portion 106 is disposed so as to be movable back and forth (up and down) in the cylinder axial direction in the cylinder portion 106, and on the proximal end side of the piston 102, the connecting rod 10 8 is connected to the crankshaft 130. The connecting rod 108 is rotatably attached to a crank pin (not shown) between the crank webs 132 provided on the crankshaft 130. As a result, the piston 102 moves back and forth in the cylinder portion 106 as the crankshaft 130 rotates.

A timing gear 134 is provided on the crankshaft 130 adjacent to the crank web 132 (specifically, the crank journal). A cam drive chain 133 as a drive force transmission member is wound around the timing gear 134. [0027] The cam drive chain 133 is wound around the cam sprocket 211 disposed in the cylinder head 104 in the engine main body 110 together with the timing gear 134, and is connected to the cam pieces 220 and 240 of the variable valve drive device 200. Transmits rotational driving force. Note that the force used as the drive force transmission member as the cam drive chain 133 is not limited to this, and any force may be used as long as the drive force is transmitted from the crankshaft 130 to the force musket 211. For example, a cog belt may be used instead of the cam drive chain 133. In this case, a configuration using a cog wheel instead of the timing gear 134 and the cam sprocket 211 is used.

Become.

[0028] The transmission line (in this embodiment, the chain line) of the cam drive chain 133 is substantially perpendicular to the crankshaft 130 and is connected to the cylinder shaft of the cylinder portion 106 in which the piston 102 moves forward and backward. It is placed at a close position. This is because, due to the structure of the engine, the crank force that drives the piston 102 also prevents the bending force applied to the crank itself from increasing as the cam drive chain 133 is pulled away as the cam drive chain 133 is separated. .

The cam drive chain 133 is disposed in a chain case portion 116 that is integrally provided adjacent to the cylinder portion 106 in the engine main body 110. Note that an upper portion 116 a (hereinafter referred to as “case upper portion”) 116 a of the chain case portion 116 is provided integrally with the cylinder head 104. The case upper portion 116a opens in the cylinder head 104 in a direction parallel to the crankshaft 130.

[0030] One of the openings 116b communicates with the space above the cylinder 106, and the other opening 116c is provided with an annular cylinder head cover (hereinafter referred to as "head cover") 105. ing. In this annular head cover 105, one end portion side of the variable valve driving device 200 is disposed, and the variable valve driving device 200 is supported by the head force bar 105 on one end portion side thereof.

[0031] The variable valve drive device 200 includes a cam sprocket 211, an exhaust cam piece 220, a variable cam shaft 230, an intake cam piece 240, an eccentric plate (eccentric member) 250, an eccentric boss (member moving part) 260, and an eccentric motor. 270. The variable valve driving device 200 is attached to the cylinder head 104 in parallel with the crankshaft 130. [0032] It should be noted that in this variable valve drive device 200, one of the valve timings of the intake valve and the exhaust valve is changed with respect to the other valve timing, so that the knob overlap amount is variable. The variable valve driving device 200 changes the closing timing of the intake valve by the intake cam piece 240 (the closing timing), thereby making the intake valve relative to the exhaust valve variable, thereby varying the valve overlap amount. .

FIG. 2 is a cross-sectional view of the main part showing the variable valve driving device 200 attached to the cylinder head 104, and FIG. 3 is an exploded perspective view of the variable valve driving device 200.

In this variable valve drive device 200, the rotation axes of the cam sprocket 211, the exhaust cam piece 220, the variable force shaft 230, the intake cam piece 240, the eccentric plate 250, and the eccentric boss 260 are parallel to each other. .

In this variable valve drive device 200, as shown in FIGS. 1 to 3, the intake cam piece 240 and the exhaust cam piece 220 are disposed in the cylinder head 104 with the variable cam shaft 230 being passed therethrough. It is arranged at the upper part of the cylinder part 106 in this.

Further, the variable cam shaft 230 is passed through the cam sprocket 211, and the cam sprocket 211 and the eccentric plate 250 are disposed in the upper case 116a!

[0037] The eccentric boss 260 is rotatably attached to the annular head cover 105.

The variable valve driving device 200 is fixed to the cylinder head 104 by fixing the head cover 105 to which the eccentric boss 260 is attached to the cylinder head 104. Note that the opening of the cylinder head 104 to which the head cover 105 on which the eccentric boss 260 is disposed has a diameter that allows the cam sprocket 211 to be inserted.

As shown in FIG. 1 to FIG. 3, the cam sprocket 211 has the same axis, and has an exhaust cam piece 220 that opens and closes a valve (here, an exhaust valve) and a cylindrical portion 224 by rotating. Are formed integrally. That is, the cam sprocket 211, the cylindrical portion 224, and the exhaust cam piece 220 form a cam drive body 210 that directly receives the drive force of the crankshaft 130 and rotates.

[0039] The cam sprocket 211 is driven by the drive of the crankshaft 130 via a timing gear 134 (see Fig. 1) and a cam drive chain 133 (see Fig. 1). Rotates at a constant reduction ratio. Here, the cam sprocket 211 rotates at a speed of 1Z2 of the rotation of the crankshaft 130! /.

[0040] The shaft centers of the cam sprocket 211 and the exhaust cam piece 220 are camshaft shaft centers, and the force shaft shaft is arranged in parallel with the crankshaft 130 (see FIG. 1) above the cylinder portion 106. Yes.

Further, as shown in FIGS. 1 to 3, the cam sprocket 211 is driven so as to protrude parallel to the rotational axis direction of the cam sprocket 211 and to the opposite side with respect to the exhaust cam piece 220. Pin 212 is provided. The drive pin 212 is loosely fitted in a drive slot 252 cut out in the radial direction from the center side of the eccentric plate 250.

The axis of the drive pin 212 is eccentric with respect to the axis of the cam sprocket 211. When the force mus procket 211 rotates, the drive pin 212 circulates around the axis of the cam sprocket 211 and rotationally drives the eccentric plate 250 via the slot 252 that is loosely fitted.

Note that a projection piece 114 protruding in the radial direction is attached to the cam sprocket 211.

[0044] The rotational position of this projection piece 114 (the rotational position of cam sprocket 211) is the cylinder head 1

Detected by sensor 114a attached to 04.

[0045] Further, a through hole 215 penetrating in the axial direction is formed in the same axial center portion of each of the cam sprocket 211, the exhaust cam piece 220, and the cylindrical portion 224, that is, the axial center portion of the cam driving body 210. Is provided. The through hole 215 communicates with a hole 223 opened in the base circle surface 220a of the exhaust cam piece 220 (see FIG. 2).

[0046] The shaft portion 230a of the variable cam shaft 230 is passed through the through-hole 215 so as to be rotatable in the axial direction.

[0047] The shaft portion 230a of the variable cam shaft 230 protrudes on both sides in the axial direction from the cam drive body 210 to be threaded, and an intake cam adjacent to the exhaust cam piece 220 is provided on a portion protruding on the exhaust cam piece 220 side. A piece 240 is physically attached.

Further, the variable cam shaft 230 is provided with a driven pin 232 at a portion of the shaft portion 230a protruding on the cam sprocket 211 side of the cam driver 210.

[0049] The variable camshaft 230 is disposed above the cylinder portion 106 while being passed through the cam driver 210. It is arranged to cross. The variable cam shaft 230 is rotatably supported by a bearing 104a and a bearing 113.

Further, the variable cam shaft 230 has a through hole 238 that penetrates in the axial direction in the shaft portion 230a, and the through hole 238 is a sliding portion between members constituting the variable valve drive device 200. It is the main oil passage for the lubricating oil to be supplied. Hereinafter, the through hole 238 will be described as the main body oil passage 238.

[0051] The main body oil passage 238 is provided through the rotation shaft of the cam drive 210 (particularly, the cam sprocket 211), and the sliding portion of the intake cam piece 240 on the other end side of the cam drive 210. Lubricating oil is supplied to the sliding portion of the eccentric plate 250 on one end side of the cam driving body 210.

[0052] Further, the main body oil passage 238 communicates with the outer peripheral surface of the shaft rod 230a through the branch oil passages 239a, 239b, and 239c, and is connected to the end face through the throttle 235 provided on the chain line side in the shaft portion 230a. Opened to the side (eccentric plate 250 side).

[0053] The branch oil passages 239a, 239b, and 239d are formed on the shaft rod 230a so as to be orthogonal to the main body oil passage 238, and open to the outer surface portion of the shaft portion 230a.

[0054] Oil sump grooves 236 and 237 formed in a concave shape in the circumferential direction of the shaft portion 230a are provided on the outer surface portion of the shaft portion 230a where the branch oil passages 239a and 239b open. These oil sump grooves 236, 237 are connected to the branch oil passages 239a, 239bi!

[0055] These oil sump grooves 236, 237 are formed in the portion that slides in contact with the inner peripheral surface of the through hole 215 constituting the inner peripheral surface portion of the cylindrical portion 224 and the exhaust cam piece 220, These sliding parts are lubricated by the lubricating oil guided to the branch oil passages 239a and 239b.

[0056] The branch oil passage 239c is formed in the shaft portion 230a so as to be orthogonal to the main body oil passage 238.

The intake cam piece 240 has an opening in the outer surface portion communicating with the hole 245.

[0057] Thereby, the lubricating oil guided by the branch oil passage 239c is transferred to the shaft portion 230a and the intake cam piece 24.

Supplied to the sliding part with 0 and lubricates this sliding part. An oil sump groove 246 is formed along the inner peripheral surface of the opening portion of the intake cam piece 240 in a portion of the intake cam piece 240 that slides on the outer peripheral surface of the shaft portion 230a.

In addition, one end of the variable cam shaft 230 is connected to the cylinder head 104 in the cylinder head 104. It is inserted in the bearing 113 attached to. The portion protruding from the bearing 113 is covered with an oil seal cap 115 via an oil seal portion 117 so that the oil seal portion 117 does not leak lubricating oil outside the cylinder head 104.

Note that an oil pump discharge port 118 is provided on one end 111 side of the cylinder head 104. The lubricating oil is press-fitted into the oil reservoir 119 communicating with the opening 230c at one end of the shaft portion 230a through the discharge port 118, and is guided into the main body oil passage 238 through the oil reservoir 119. The oil pump pumps up lubricating oil from a lubricating oil reservoir (for example, an oil pan 6 20 provided in the motorcycle 500 shown in FIG. 11) provided in a vehicle on which the engine 100 is mounted.

[0060] The intake cam piece 240 is externally fitted to one end side of the shaft portion 230a, and is fixed by fitting the pin 241 into a notch 243 (see FIG. 3) formed in the intake force piece 240. Has been. The intake cam piece 240 is disposed above the cylinder portion 106 together with the exhaust cam piece 220.

[0061] When the intake cam piece 240 rotates about the axis of the variable cam shaft 230, the intake cam piece 240 is driven to rotate about the coaxial axis. Further, as shown in FIG. 2, the intake cam piece 240 is formed with a hole 245 that penetrates the base circle surface 240a and the inner surface of the opening that fits into one end of the shaft portion 230a. The hole portion 245 communicates with the main body oil passage 238 in the shaft portion 230a.

[0062] With this configuration, when the lubricating oil is discharged from the discharge port 118, in the cylinder head 104, the lubricating oil passes through the branch oil passages 239c, 239b, 239a, and the intake cam piece 240, the exhaust cam Supplied to each sliding portion of each piece 220 and each cam profile portion.

[0063] On the other end side of the shaft portion 230a, a plate 234 protruding perpendicular to the shaft center of the shaft portion 230a is attached. The plate 234 rotates at a position adjacent to the cam sprocket 211 as the shaft portion 230a rotates.

[0064] At the tip of the plate 234, a driven pin 232 that protrudes in a direction opposite to the direction in which the shaft portion 230a extends and faces the drive pin 212 across the axis of the shaft portion 230a is provided (see FIG. 1 to Figure 3). The driven pin 232 is disposed on the plate 234 at a position parallel to the axis of the shaft part 230a and eccentric with respect to the axis of the shaft part 230a.

[0065] Then, this follower pin 232 is arranged at the center of the eccentric plate 250 in the eccentric plate 250. The force is also loosely fitted in the driven slot 254 cut out in the radial direction, and rotates around the axis of the shaft portion 230a by the rotation of the eccentric plate 250. That is, when the drive pin 212 that rotates with the rotation of the cam sprocket 211 drives the eccentric plate 250 to rotate, the variable cam shaft 230 is driven via the driven slot 254 and the driven pin 232, and the intake cam piece 240 is Rotate.

[0066] The eccentric plate 250 is a plate-shaped (mainly disc-shaped) plate main body 256 disposed opposite to the plate 234 of the variable cam shaft 230, and the opposite side of the plate 234 from the center of the plate main-body 256. And a plate shaft portion 258 projecting vertically.

The plate main body 256 is formed on the same straight line so as to extend in the radial direction with the drive slot 252 and the driven slot 254 force plate shaft portion 258 interposed therebetween.

A drive pin 212 and a follower pin 232 are loosely fitted in the drive slot 252 and the follower slot 254, respectively. The drive pin 212 and the follower pin 232 are eccentric plates by the rotation of the force mus procket 211. Move on the same straight line passing through 250 axes. That is, a phase angle difference is generated between the rotation of the cam sprocket 211 and the exhaust cam piece 220 and the rotation of the intake cam piece 240 via the drive pin 212 and the driven pin 232.

[0069] The plate shaft portion 258 is a rotation shaft of the eccentric plate 250 itself, and is rotatably inserted into an eccentric hole 262 formed in the eccentric boss 260 as shown in FIG.

[0070] The eccentric boss 260 has a boss main body 264 that rotates around the rotation axis parallel to the cam shaft direction (rotation center R shown in FIG. 3) inside the head cover 105.

The eccentric boss 260 whose outer diameter is smaller than the outer diameter of the cam sprocket 211 is disposed at a position overlapping the cam sprocket 211 in the rotation axis direction. The eccentric hole 262 in the eccentric boss 260 is formed in the boss main body 264 at a position eccentric with respect to the rotation center.

[0072] In other words, the eccentric boss 260 is opposed to the cam sprocket 211 across the eccentric plate 250 in the direction of the rotation axis of the cam drive 210, and the rotation axis (rotation center) of the eccentric boss 260 is The cam drive 210 is positioned inside the outer peripheral edge of the cam sprocket 211 that faces the eccentric boss 260. According to this configuration, the rotation center of the eccentric boss 260 is located inside the outer peripheral edge of the cam sprocket 211. For this reason, the eccentric plate 250 is eccentric. Mechanical force The entire variable valve drive device 200 that is positioned outward from the outer peripheral edge located in the radial direction in the cam drive 210 is made compact.

[0073] A rack 266 is provided on a part of the outer periphery of the boss main body 264, and the rack 266 meshes with a worm gear 272 of an eccentric motor 270 attached to the head cover 105. With this configuration, the eccentric boss 260 rotates around the rotation center R (see FIG. 3) by driving the eccentric motor 270 inside the head cover 105.

FIG. 4 is an exploded perspective view of the eccentric boss 260.

[0075] As shown in Fig. 4, the eccentric boss main body 264 of the eccentric boss 260 has a bottomed cylindrical shape, and a lid 264b is attached to a main body case 264a in which an eccentric hole 262 is formed. Composed.

[0076] Around the main body gaze 264a, the surrounding wall 262a is provided with a partition wall 265a, 265b, 265c [compartment compartments 267a, 267b, 267c].

[0077] An air hole 268 is provided in the bottom portion of the compartment 267a so as to communicate the compartment 267 with the back side of the eccentric boss 260, that is, the eccentric plate 250 side. An oil return hole 268a communicating with the outside of the eccentric boss main body 264 is formed in the peripheral wall portion of the compartment 267a.

[0078] Further, the partition walls 265a and 265b are provided with notches 269, so that the compartments 267a and 267b and the compartments 267b and 267c communicate with each other! /.

[0079] The lid 264b covers the compartments 267a, 267b, 267c. The lid 264b has an opening 264c formed in the ceiling portion of the compartment 267c.

As described above, the eccentric boss 260 is configured to communicate with the axial direction, that is, the front and back surfaces via the air hole 268, the compartments 267a, 267b, 267c, the notch 269, and the opening 264c. Yes. In other words, the eccentric boss 260 is provided with compartments 267a, 267b, 267c as hollow portions that communicate with the cam sprocket 211 in the rotational axis direction.

With this configuration, the eccentric boss 260 allows the inside and outside of the cylinder head 104 to communicate with each other when the eccentric boss 260 is attached to the cylinder head 104 via the head cover 105.

An oil return hole 105 a is formed in the head cover 105 in parallel with the rotational axis of the eccentric boss 260. As a result, the oil return hole 105a is eccentrically inserted into the eccentric boss 260. When lubricating oil flows from the engine 250 side, the lubricating oil is returned to the engine 100 together with the oil return hole 268a communicating with the compartment 267a. That is, the compartments 267 a, 267 b, and 267 c function as breather chambers that prevent the lubricant in the blow-by gas generated in the engine 100 from being discharged outside the engine 100.

By the rotation of the eccentric boss 260 configured as described above, the position of the eccentric hole 262 can be moved to a position eccentric with respect to the rotation center R of the boss main body 264. In other words, the eccentric boss 260 is disposed adjacent to the eccentric plate 250 on the opposite side to the cam sprocket 211, and the plate shaft portion 258 of the eccentric plate 250 is coaxially positioned with respect to the rotation axis of the cam sprocket 211. Can be moved to a position.

FIG. 5 is a diagram showing the positional relationship between the rotation center R of the eccentric boss 260, the axis C of the cam sprocket 211, and the axis E of the eccentric plate 250. Specifically, Fig. 5 (a) is a schematic front view of the eccentric boss 260, cam sprocket 211 and eccentric plate 250, and Fig. 5 (b) is the rotation center R and axis C shown in Fig. 5 (a). It is an enlarged view of E part.

[0085] As shown in FIG. 5, the eccentric boss 260 is rotatably fitted in the head cover 105, and the center of rotation (boss center) R is centered by the eccentric motor 270 (see FIGS. 1 to 3). Rotate. The rotation center R is fixed on the engine side, and the rotation center (camshaft axis) C of the variable cam shaft 230, the exhaust cam piece 220, and the intake cam piece 240 (center of eccentricity) E It is the center of rotation that rotates.

[0086] Since the plate shaft portion 258 (the shaft center E of the eccentric plate 250) is rotatably inserted into the eccentric hole 262 of the eccentric boss 260, the shaft center of the eccentric plate 250 is rotated by the rotation of the eccentric boss 260. (Eccentric center) E moves in a circular arc around the center of rotation (boss center) R.

Further, on the movement line of the axis E, the axis C of the variable cam shaft 230, that is, the axis C of the exhaust cam piece 220 and the intake cam piece 240 is arranged!

[0088] By rotating about the boss center R of the eccentric boss 260, the shaft center E of the eccentric plate 250 is eccentric with the axis C of the variable cam shaft 230, so that the exhaust cam piece integral with the cam sprocket 211 is obtained. With respect to the rotation of 220, a phase difference can be set in the rotation of the intake cam piece 240 integrated with the variable cam shaft 230.

[0089] Further, the rotation of the eccentric boss 260 allows the axis E and the axis C to coincide with each other. The The eccentric boss 260 is moved at a position where the shaft center E and the shaft center C coincide with each other, that is, the position of the shaft center E of the eccentric hole 262 of the eccentric boss 260 and the position of the shaft center C of the variable cam shaft 230. Can be fixed. Thereby, the eccentric plate 250 and the variable cam shaft 230 can be rotated around the same axis. Further, since the axis E of the eccentric plate 250 moves in an arc shape in the eccentric boss 260, that is, in the opening of the head cover 105, a mechanism for eccentrically locating the axis E of the eccentric plate 250 is accommodated in the head cover 105. It is in the state.

The rotational angle position of the eccentric boss 260 in the head cover 105 is detected by angle sensor units 26 and 27 provided on the eccentric boss 260 as shown in FIG.

The angle sensor units 26 and 27 can detect the position of the eccentric hole 262, that is, the eccentric position of the eccentric plate 250 by detecting the rotational angle position. Using the information detected in this way, the information obtained from the engine side force such as the engine rotation and the engine load, and the information that the user force is also input via the operation unit (not shown), the eccentric position of the eccentric hole 262 is It is controlled to a preset position by the control unit 150 (see FIG. 6).

FIG. 6 is a schematic diagram for explaining a control unit of an engine including the variable valve drive device 200 according to one embodiment of the present invention.

As shown in FIG. 6, engine 100 includes a control unit 150 that drives and controls the engine itself and drives and controls the eccentric motor 270 (see FIGS. 1 and 3) of the variable valve driving device 200.

The control unit 150 is connected to an angle sensor unit 27 that detects the rotational angle position of the eccentric boss 260, and determines the eccentric position of the eccentric plate 250 based on information input from the angle sensor 27.

In addition, the control unit 150 is connected to the sensor 114a, and receives the rotational position information of the force musprocket 211 detected by the sensor 114a.

[0096] The cam sprocket 211 is connected to the crankshaft 13 via a cam drive chain 133 (see FIG. 1).

Since the driving force of 0 is directly transmitted, the rotational position of the cam sprocket 211 (corresponding to the rotational position of the protruding piece 114) is linked to the stroke of the crank.

[0097] That is, the rotational position of the cam sprocket 211 has a crank stroke (in the case of 4 cycles, the suction stroke). Information on the input stroke, compression stroke, explosion stroke and exhaust stroke). Sensor 1 for this

14a detects the position of the protrusion 114 of the cam sprocket 211, thereby

0 can determine the crank stroke.

In addition, a crank angle detection sensor 160 that detects a crank angle of the crankshaft 130 is connected to the control unit 150, and the control unit 150 uses crank angle information detected by the crank angle detection sensor 160. Determine the engine speed.

[0099] The control unit 150 operates the motor so as to form a cam working angle (Duration: also referred to as "operating angle") corresponding to the engine speed based on information input from each sensor 27, 114a, 160. Sets current and outputs to eccentric motor 270 to drive and control eccentric motor 270

[0100] The control unit 150 changes the valve timing based on the engine speed so as to obtain a suitable overlap amount corresponding to the actual engine speed.

[0101] In addition, the control unit 150 drives the eccentric motor 270 when the engine speed is at or near the maximum, and the axis E of the eccentric plate 250 and the axis C of the variable cam shaft 230 are driven. To be aligned with the axis C. The valve operating angle at this time is the maximum operating angle.

[0102] Control unit 150 is connected to an injector (not shown), and drives and controls the injector by outputting a fuel injection control signal to the injector. In addition, it is connected to a plug (not shown) and outputs an ignition timing control signal to the plug to control the ignition timing of the plug.

[0103] Next, the operation of the variable valve drive apparatus 200 in the present embodiment will be described.

In the variable valve drive device 200 shown in FIGS. 1 to 3, the cam sprocket 211 is driven by the rotation of the crankshaft 130 through the cam drive chain 133 at half the rotation of the crankshaft 130. . As the cam sprocket 211 rotates, the exhaust cam piece 220 that constitutes the cam drive body 210 together with the cam sprocket 211 rotates in synchronization with the rotation of the crankshaft 130.

In addition, the drive pin 212 loosely fitted in the input side slot 252 of the eccentric plate 250 by the rotation of the cam sprocket 211 presses the eccentric plate 250 around the plate shaft portion 258 via the drive slot 252. Then, the eccentric plate 250 is rotated. [0106] Since the center of rotation of the eccentric plate 250, that is, the position of the plate shaft portion 258 is decentered by driving the eccentric motor 270, even if the cam sprocket 211 rotates at a constant speed. The eccentric plate 250 rotates at a non-uniform speed.

FIG. 7 is a diagram showing an example of the positional relationship between the drive pin and the driven pin in a state where the center of the eccentric plate is eccentric with respect to the cam shaft in the variable valve driving device.

FIGS. 7A to 7I show the relative positional relationship between the drive pin 212 and the drive pin 232 in a stepwise manner when the crankshaft is rotated at a predetermined rotation. The slots 252 and 254 (see FIGS. 1 and 3) in which the drive pin 212 and the driven pin 232 are loosely fitted are formed on the same straight line, and therefore are schematically shown as a straight line SL.

[0109] When the drive pin 212 is on the center of the eccentric plate 250 with respect to the axis C of the cam sprocket 211 (rotation axis) E side, the distance force between the center of the eccentric plate 250 and the center of the drive pin 212 It is smaller than the distance between the center of 211 and the center of the drive pin. Therefore, the rotation angle of the eccentric plate 250 is larger than the rotation angle of the cam sprocket 211.

[0110] On the other hand, when the drive pin 212 is on the opposite side, that is, on the side where the central force of the eccentric plate 250 is also away from the axis C of the cam sprocket 211, between the center of the eccentric plate 250 and the center of the drive pin 212. Distance force Becomes larger than the distance between the center of the cam sprocket 211 and the center of the drive pin. Therefore, the rotation angle of the eccentric plate 250 is smaller than the rotation angle of the cam sprocket 211.

In addition, the slot 254 formed in the plate main body portion 256 of the eccentric plate 250 rotates at a non-uniform speed similarly to the eccentric plate 250. Since the driven pin 232 loosely fitted in the slot 254 is concentric with the cam sprocket 211 and the intake cam piece 240, an inconstant speed motion is transmitted to the driven pin 232 via the slot 254. The shaft portion 230a rotates at a non-uniform speed through the driven pin 232 to which the non-uniform speed motion is transmitted, and the intake cam piece 240 rotates at a non-uniform speed accordingly.

For example, it is assumed that the intake cam piece 240 is driven at an angular speed faster than half of the rotational speed of the crankshaft 130 in the vicinity of the crank angle at which the intake cam piece 240 is open. At this time, when the crank rotates by an operating angle (for example, 268 degrees), the cam rotates more than the operating angle, so the intake valve is opened and closed in a shorter time. In other words, the working angle is narrowed. While sucking When the air cam rotates slowly, the working angle can be widened.

In this way, in the variable valve drive device 200, the intake cam rotated by the variable cam shaft 230 driven via the eccentric plate 250 with respect to the exhaust cam piece 220 provided integrally with the cam sprocket 211. The rotation phase difference of the piece 240 can be periodically changed.

That is, the eccentric plate 250 is eccentric with respect to the camshaft axis, and the operating angle of the intake cam piece 240 is periodically variable. In other words, the intake cam piece 240 rotates at an unequal speed, and this rotation The operating angle and opening / closing timing of the intake valve (variable valve) that opens and closes can be varied.

[0115] Specifically, in the variable valve drive 200, when the cam operating angle is increased, the cam rotation speed decreases while the knob is open, and the cam rotation speed when the valve is closed. Go up. If the cam operating angle is reduced, the cam rotation speed increases while the knob is open, and the cam rotation speed decreases when the knob is closed.

[0116] In this manner, the intake cam piece 240 can be rotated with a rotational phase difference provided with respect to the exhaust cam piece 220, and this rotational phase difference is appropriately changed as a periodic rotational phase difference. As a result, the valve overlap amount can be varied according to the engine stroke.

[0117] Note that the timing at which the intake cam piece 240 is rotated faster with respect to the exhaust cam piece 220 and at which timing the intake cam piece 240 is rotated slowly depends on the eccentric plate relative to the center of the cam sprocket 211.

It is determined by the positional relationship between the center of 250 and the cam nose and slots 252 and 254.

[0118] Fig. 8 shows a valve operating angle set corresponding to an engine speed and a mean effective pressure in an engine including a variable valve drive device 200 according to an embodiment of the present invention. FIG.

[0119] The operating angle shown in Fig. 8 is the optimal operating angle according to the engine speed (corresponding to the operating range). For example, when the average effective pressure is 4 at 3000 rpm, the optimum valve working angle is about 210 degrees.

[0120] The maximum engine speed of engine 100 is 9000 rpm here. Maximum speed is

In the engine 100 with a predetermined displacement mounted with the variable nozzle drive device 200, It is set based on the maximum output required for the engine 110. In other words, the maximum engine speed can be set based on the maximum piston speed that can be achieved in the engine 100 taking into account torque.

[0121] As shown in FIG. 8, in the engine 100, the controller 150 controls the center C of the cam sprocket 211 (see FIGS. 3 and 5) and the center of the eccentric plate 250 at an engine speed of 9000 rpm. Match E (center of eccentricity, see Fig. 3 and Fig. 5). At a rotational speed between 0 and 9000 rpm, the control unit 150 rotates and moves the eccentric boss 260 so that a cam operating angle suitable for each rotational speed is set, and the axis C of the cam sprocket 211 The force also decenters the center E of the eccentric plate 250 by a predetermined distance.

[0122] Fig. 9 is a view for explaining the variable state of the valve by the variable valve driving device according to one embodiment of the present invention. In FIG. 9, in the variable valve driving device 200, when the intake force piece 240 is made variable, the opening timing of the intake valve driven by the intake cam piece 240 is substantially fixed, and the closing timing is made variable. . Fig. 9 (a) shows the lift curve of the intake valve when the closing timing is variable, and Fig. 9 (b) shows the acceleration curve of the valve shown in Fig. 9 (a).

As shown in FIG. 9 (a), in the present variable valve drive device 200, the opening / closing timing and lift curve of the intake cam piece 240 change from L1 to L3 by changing the intake cam piece 240.

The intake piece 240 is varied by rotating the eccentric boss 260 in the variable valve driving device 200 to decenter the axis of the eccentric plate 250 from the camshaft axis.

[0125] The lift curve L1 in Fig. 9 (a) has the maximum operating angle D1, and at this time, in the variable valve drive device 200, the axis of the cam sprocket 211 (axis E shown in Fig. 5). And the center of the eccentric plate, that is, the center of eccentricity (axis C shown in Fig. 5) substantially coincides.

[0126] The acceleration of the valve at this time is an acceleration curve A1 shown in Fig. 9 (b). As can be seen from this acceleration curve A1, when the axis of the cam sprocket 211 coincides with the center of the eccentric plate 250, the fluctuation range of acceleration when the valve is opened and closed is close to 0, and the acceleration force curve is on the open side. And a substantially symmetrical shape on the closed side, that is, left and right. In other words, if the axial center of the force mus procket 211 is aligned with the center of the eccentric plate, there will be no distortion on the open side and on the close side in the acceleration curve of the valve. [0127] Therefore, even when the opening / closing timing of the nozzle having the lift curve LI with the maximum operating angle of the intake cam piece 240 is reached, the fluctuation range of the inertial force accompanying the rotation of the crankshaft 130 may be large. Vibrations caused by the opening and closing of the narebu are less likely to occur. As a result, the engine is driven stably.

[0128] In addition, the acceleration curve A1 of the valve that opens and closes is close to 0 due to negative acceleration fluctuations that cause acceleration distortion. Therefore, the valve acceleration exceeds the cam acceleration. Bouncing phenomenon that jumps when seated on the valve seat ring is less likely to occur.

[0129] In contrast to the lift curve L1 at the maximum operating angle shown in Fig. 9 (a), the lift curves L2 and L3 have a lower operating angle compared to the lower operating angle of the lift curve L1. As a result, the acceleration curve (see Fig. 9 (b)) deforms, increasing the maximum acceleration and decreasing the minimum acceleration force (negative acceleration increases).

[0130] By increasing the maximum acceleration in this way, for example, in the cam profile of a SOHC type valve system equipped with a push rod and a rocker arm, the timing is close to the timing of opening or closing of the valve. Due to the structure, concave rounds are likely to occur.

[0131] For this reason, in order to prevent the formation of a concave radius due to the limitations of cam camshafts, it is necessary to improve the cam power machine and inspection equipment in order to process the concave radius. Has to limit the maximum acceleration in cam drive. As a result, the maximum lift amount that can be taken in the cam profile is limited, and the maximum output or the average effective pressure is lowered.

[0132] Further, as the minimum acceleration decreases, the absolute value of the negative inertia force due to the mass of the valve system (the mass of the valve and parts attached to the valve) increases. As a result, the valve panel load must be increased to increase the reaction force of the valve panel so that the valve does not behave abnormally. For this reason, there is a problem that friction loss increases and fuel consumption deteriorates.

[0133] Further, in the case of a direct-acting lifter type valve system, a force sp (point) is generated due to a decrease in minimum acceleration, and a cam profile is not established. For this reason, the maximum lift is limited and the maximum output is limited by cam profile creation restrictions that do not cause cusps. The problem of becoming low occurs.

[0134] As described above, in general, the cam profile must have a convex radius, and if the rotational direction is positive, machining is limited so as to reduce the concave radius generated by the increase in positive and negative acceleration in valve opening and closing as much as possible. It has been.

On the other hand, in the variable valve drive device 200, when the operating angle is the maximum, the control unit 105 rotates the eccentric boss 260 so that the position of the axis E of the eccentric hole 262 and the variable cam shaft 230 Overlapping with the position of axis C, control is performed on the same axis.

[0136] In other words, the cam profile can be set based on the valve lift curve on the high operating angle side, and the valve lift curve with a low operating angle that is subject to cam processing limitations is realized by the periodic angular velocity. . This is advantageous from the viewpoint of engine output or fuel efficiency.

[0137] By setting the valve lift curve force cam profile on the high operating angle side, the valve lift curve at the low operating angle is affected by periodic angular velocity fluctuations, and the maximum calorie velocity increases. The absolute value of the minimum acceleration also increases. However, a low lift angle valve lift force has a lower inertia force than that at high engine speed in order to minimize valve overlap, and is often required at low engine speeds.

[0138] For this reason, in the variable valve drive device 200 that realizes a valve lift curve with a low operating angle based on the periodic cam angular velocity, vibration and behavior caused by inertia force as well as driving of the valve system when the cam is variable. It is hard to be affected by.

Therefore, the variable valve drive apparatus 200 has low vibration and stable valve behavior at any engine speed. That is, the engine 100 equipped with the variable noble drive device 200 can stably drive the engine in any engine rotation region.

[0140] Therefore, when the amount of overlap is controlled and the idling cam piece 240 opens and closes the valve early during idling, the overlap is reduced or eliminated, thereby introducing residual gas (combustion gas). And the combustion of gas can be stabilized.

[0141] Further, it is possible to reduce the scavenging and blow-back of the residual gas due to the exhaust pulsation effect, and further improve the intake effect of the air-fuel mixture so that a sufficient air-fuel mixture is sucked and idling is performed. Stabilization and startability can be improved.

[0142] Further, blowout can be prevented, hydrocarbons in the exhaust gas can be reduced, and engine output at low engine speed can be increased to improve fuel efficiency.

[0143] In particular, when the engine is running at a low speed, the intake cam piece 240 is rotated so that the intake valve is fully closed when the piston 102 is located at the bottom dead center.

[0144] Also, when the engine is running at medium speed (medium load range), the intake valve is opened wide from the early stage to increase the overlap so that the bombing loss can be reduced, the combustion efficiency can be increased, and the fuel efficiency can be improved. be able to.

[0145] In particular, when an engine having a variable valve timing mechanism is mounted in a motorcycle, conventionally, in a motorcycle, it has been common to determine the operating angle with an emphasis on output. The motivation to adopt is often to improve fuel efficiency and exhaust at low speeds. Therefore, there is a great demand for setting the valve lift curve in the structure of the variable valve timing mechanism to be variable on the low working angle side with respect to the conventional engine.

[0146] According to this variable valve drive device 200, the same layout as that of a conventional engine, without a variable valve drive mechanism, and with a specification cam shape and a specification force mechanism with a variable valve drive mechanism. The same shape can be achieved, and the sharing of production equipment and parts can be promoted.

Furthermore, the variable valve driving device 200 configured as described above is configured such that the exhaust cam piece 220 and the intake cam piece are on the cam axis as compared with a variable valve drive mechanism, that is, a cam shaft without a so-called variable bubble timing mechanism. The positional relationship between 240 and the cam sprocket 211 remains the same. Therefore, in a conventional motorcycle without a variable valve drive mechanism, for example, an engine structure of a starter, it can be used as an engine having a variable valve function only by changing the camshaft portion to the variable valve drive device 200. .

In detail, in order to mount the variable valve driving device 200, the dimensions and arrangement positions of each member for driving the camshaft such as the crankshaft, the cylinder portion and cylinder head of the engine main body, and the timing gear are specified. There is no change.

In the present embodiment, engine 100 is a single cylinder SOHC (Single Over Head Camshaft). Not only this but also a multi-cylinder SOHC type, DOHC (Double Over Head Camshaft).

[0150] In this variable valve drive device 200, as shown in FIG. 9, the intake valve closing timing of the intake valve that is opened and closed by the intake cam piece 240 is made variable so that the rotational position of the intake cam piece 240 relative to the exhaust cam piece 220 Force that periodically changes the phase difference.

[0151] For example, in the variable valve drive device 200, when the intake cam piece 240 is made variable,

The closing timing of the intake valve driven by the intake cam piece 240 may be substantially fixed, and the opening timing may be variable. An example of this will be described with reference to FIG.

[0152] Fig. 10 is a view for explaining a modification of the variable state of the valve by the variable valve driving device according to the embodiment of the present invention. Specifically, Fig. 10 (a) shows the lift curve of the intake valve when the opening timing is variable, and Fig. 10 (b) shows the acceleration curve of the valve shown in Fig. 10 (a).

[0153] As shown in Fig. 10 (a), the opening / closing timing and lift curve force L4 of the intake cam piece 240 are changed by changing the opening timing and changing the noble timing by the intake cam piece 240.

Change to ~ L6.

[0154] The lift curve L4 in Fig. 10 (a) has the maximum operating angle D4. At this time, in the variable valve drive device 200, the axis of the cam sprocket 211 (the axis E shown in Fig. 5). ) And the center of the eccentric plate, that is, the center of eccentricity (axis C shown in Fig. 5) substantially coincides.

[0155] The acceleration of the valve at this time is an acceleration curve A4 shown in Fig. 10 (b).

[0156] As can be seen from this acceleration curve A4, when the axis of the cam sprocket 211 and the center of the eccentric plate 250 match, the fluctuation range of acceleration when the valve is opened and closed is close to 0, and the acceleration curve is The opening side and the closing side, that is, the left and right sides are substantially symmetrical.

[0157] Also, if the center of the eccentric plate 250 is decentered with respect to the axis of the cam sprocket 211, it changes as lift curves L5 and L6, and the acceleration curves in these lift curves L5 and L6 are also A5, It changes with A6. That is, as shown in FIG. 10, by making the eccentric plate 250 eccentric with respect to the cam sprocket 211, the maximum acceleration on the closing side increases, the minimum acceleration decreases, and the acceleration curve is distorted.

[0158] When the axis of cam sprocket 211 is aligned with the center of the eccentric plate The operating angle of the nozzle is the maximum operating angle D4, and there is no distortion on the open side and close side in the acceleration curve of the valve at that time.

[0159] Therefore, even when the opening / closing timing of the knob having the lift curve L4 where the working angle of the intake cam piece 240 is the maximum, the fluctuation range of the inertial force accompanying the rotation of the crankshaft 130 may be large. Vibrations caused by the opening and closing of the narebu are less likely to occur. As a result, the engine is driven stably.

[0160] In addition, the acceleration curve A4 of the valve that opens and closes is a negative acceleration force SO that causes the speed distortion, so the valve movement is not the regulation of the cam. The bounce phenomenon that jumps when sitting on the floor is less likely to occur.

[0161] According to the variable valve drive device 200 provided in the engine 100 as described above, the eccentric center E of the eccentric plate 250 can be obtained at the maximum rotation speed of the crankshaft or at the high rotation speed of the engine near the maximum rotation speed. The position matches the camshaft axis C. Therefore, at the time of high engine rotation, the intake cam piece 240 that does not cause the eccentric plate 250 to be eccentric can be rotationally driven to open and close the intake valve.

[0162] In other words, since the eccentric plate 250 does not rotate at the eccentric position when the engine 100 is rotating at a high speed, there is a rotational phase difference with respect to the intake cam piece 240 force cam sprocket 211 via the movable cam shaft 230. And does not fluctuate periodically. As a result, the change in the acceleration curve of the exhaust valve or intake valve driven to open or close is very small (the amount of change is close to 0).

[0163] Accordingly, the inertial force is the largest in terms of kinematics, and stable valve behavior with low vibrations at the time of high engine rotation is likely to cause problematic valve behaviors such as a jumping phenomenon and a bounce phenomenon. Can do.

[0164] In addition, when the engine is running at low and medium speeds, the control unit 150 moves the eccentric plate 250 as appropriate to make it eccentric from the axis C (camshaft axis) of the cam sprocket 211, thereby improving fuel efficiency. In addition, the driving for reducing the exhaust gas is performed. When the engine is rotating at low and medium speeds, the inertial force is small, so the fluctuation in the acceleration of the intake valve due to the eccentricity of the eccentric plate 250 does not matter.

[0165] Therefore, by using the variable valve drive device 200, the entire engine operation range (all All engines have a low vibration and stable valve behavior, and the effective output can be maximized. The engine is also excellent in terms of fuel consumption and exhaust gas.

[0166] Further, in this variable valve drive apparatus 200, the rotational phase difference of the intake cam piece 240 varies periodically with respect to the exhaust exhaust cam piece 220 that varies the operating angle of the intake valve. Not limited to this. That is, the rotational phase difference of the exhaust cam piece 220 may be periodically changed with respect to the intake cam piece 240.

In this case, the variable valve drive device 200 includes an intake cam piece that drives the intake valve by rotating integrally with the cam sprocket 211, and an exhaust cam that drives the exhaust valve on the variable cam shaft 230. The structure is provided with a piece.

[0168] With this configuration, the amount of overlap can be changed by varying the operating angle of the exhaust valve, and the same effect as described above can be obtained. In detail, the opening timing and closing timing of the exhaust valve, which cause the working angle of the exhaust valve, can be set separately, similarly to the setting of the opening timing and closing timing of the intake valve described above.

[0169] Next, an example of a vehicle equipped with the engine 100 including the variable valve drive device 200 will be described in detail.

Here, the power on which the vehicle equipped with engine 100 is described as a starter type motorcycle is not limited to this, and any vehicle as long as it is equipped with engine 100 may be used.

[0171] Fig. 11 is a schematic side view showing a configuration of a main part of a motorcycle including the variable valve drive device for an engine according to one embodiment of the present invention. In the present embodiment, front, rear, left, and right mean front, rear, left, and right when viewed in the state of being seated on the seat of the motorcycle. Although the motorcycle in the present embodiment is described as a starter type motorcycle, the present invention is not limited to this, and any vehicle may be used as long as it has a variable valve drive device 200.

A motorcycle 500 shown in FIG. 11 is a tandem starter type, and includes a tandem seat 504 on the rear side of a vehicle main body 503 that rotatably supports a handle 502 on the front side. The tandem seat 504 is attached to the trunk space 505 arranged at the lower part so as to be freely opened and closed. Below this trunk space 505, a drive unit 600 is arranged. ing.

[0173] The front end portion of the drive unit 600 is a pivot shaft (not shown) horizontally disposed in the vehicle width direction at the rear end portion of the front main body 503a extending from the lower side of the handle 502 to the lower side of the tandem seat 504. ) And can be swung up and down.

[0174] Further, a rear wheel 508 is attached to the rear end portion of the drive unit 600 via an axle 510, and the rear end portion and a frame pivot that supports the rear end portion of the trunk space 505 are rear. Suspension 512 is suspended. Note that the front end of the trunk space 505 is disposed in front of the upper end of the front end of the drive unit 600.

FIG. 12 is a schematic plan view showing the main part of the drive unit of FIG.

As shown in FIG. 12, in drive unit 600, engine 100 is mounted on the front side of the vehicle, and the driving force of engine 100 is applied to axle 510 arranged at the rear end of drive unit 600, with the C VT mechanism. The rear wheel 508 is rotated by being driven to rotate through the part 610.

[0177] In addition, engine 100 has a substantially central portion in the vehicle front-rear direction below trunk space 505, with the axis of cylinder portion 106 being substantially horizontal and crankshaft 130 being substantially parallel to the vehicle width direction. Is located.

[0178] A CVT mechanism portion 610 extending rearward of the vehicle is disposed on the other end portion side of the crankshaft 130, here, on the left end portion of the vehicle. The binding mechanism 610 is arranged substantially parallel to the cylinder shaft, and includes a pulley 611 attached to the crankshaft 130, a pulley 612 attached to the axle 510, and a benolet 613 spanned between the pulleys 611 and 612. And a centrifugal clutch 61 4.

[0179] Centrifugal clutch 614 is attached to axle 510. In addition, a deceleration gear 615 is attached to the axle 510, and the driving force of the crankshaft 130 transmitted through the pulley 611 and the belt 613 is decelerated.

[0180] In motorcycles, it is conceivable to install a variable valve timing mechanism due to exhaust gas regulation problems, etc. Especially in starter type vehicles (hereinafter referred to as “starters”), etc. It is desirable that the engine structure be simplified.

[0181] The engine 100 of the present embodiment includes a cam drive body 210 corresponding to a cam drive shaft in a conventional engine configuration, and an exhaust and intake cam piece 220 disposed above the cylinder portion 106, No eccentric plate 250 corresponding to the eccentric member is arranged between the two.

In engine 100, eccentric plate 250 and exhaust and intake cam pieces 220 and 240 are arranged on the cam axis with cam drive body 210 interposed therebetween.

That is, the cam sprocket 2 arranged on the chain line of the cam drive chain 133

An eccentric plate 250 and exhaust and intake cam pieces 220 and 240 are arranged on the cam axis along the 11.

[0184] The exhaust and intake cam pieces 220 and 240 are arranged on the upper part of the cylinder portion 106 along the cylinder axis CL due to the engine structure. Therefore, unlike the conventional configuration, the cylinder axis and the cam chain line are adjacent to each other. The structure is arranged at a position.

Therefore, as shown in FIG. 12, the chain line L of the engine 100 has a conventional configuration in which an eccentric member is disposed between the cam sprocket 211 and the exhaust and intake cam pieces 220 and 240. Compared to the chain line LA, it is arranged closer to the cylinder axis CL.

As a result, the belt 613 line of the CVT mechanism 610 disposed outside the chain line L and substantially parallel to the chain line L is closer to the cylinder axis CL than in the conventional structure.

[0187] Therefore, the lateral width of the drive unit 600 itself is reduced. Specifically, in the drive unit 600, the left end surface 600a is closer to the right side than the left side surface 600b when the engine equipped with the conventional variable valve drive device is mounted, as the chain line L approaches the cylinder axis CL. Approach the side.

In other words, starter type motorcycle 500 is structurally provided with components provided on the outer side of cam drive chain 133 on the crankshaft, such as a sheave for CVT (Continuously Variable Transmission).

[0189] In the engine 100 mounted on such a motorcycle 500, a member for driving a variable valve is provided on the cam shaft between the chain line L of the force drive chain 133 and the cylinder axis CL. There is no. As a result, it is not necessary to provide a space corresponding to the member on the crankshaft 130, and the cam sprocket 211 and the cam pieces 220 and 240 (see FIG. 5) are compared with the engine having the conventional variable valve timing mechanism. 1 to 3) are not separated.

[0190] In other words, the cam drive chain 133 disposed substantially orthogonal to the crankshaft 130 Chain line L force Cylinder axis CL force is not separated.

[0191] Thus, the motorcycle 500 has the same crankcase 112 width as that of the structure without the variable valve timing mechanism.

[0192] Therefore, a sufficient bank angle in the motorcycle 500 can be obtained, and the motion characteristics of the vehicle can be ensured.

[0193] Furthermore, in the variable valve drive device 200, the eccentric mechanism portion such as the eccentric plate 250 is disposed between the exhaust and intake cam pieces 220, 240 and the cam sprocket 211!

[0194] For this reason, in the engine 100, structures other than the variable valve driving device 200 can use substantially the same components as the engine without the variable valve driving device 200. That is, the variable valve drive device 200 is provided by simply removing the variable valve drive device 200 from the cylinder head 104 of the engine body 110 and changing the eccentric plate 250, the variable cam shaft 230, the eccentric boss 260, and the head cover 105. It can be used as an engine.

[0195] Therefore, even when installed in a motorcycle, there is no need to change the structure significantly compared to the conventional engine. Engine components can be shared.

[0196] In addition, since an eccentric mechanism such as an eccentric plate is arranged between the cam sprocket and the camshaft in the engine, the bending strength of the crank that is generated when the cam sprocket is separated from the cylinder axial force. The decline will never drop! ,.

[0197] Unlike the structure in which the cam drive shaft itself is moved in the axial direction, the overlap period can be varied with a simple configuration.

[0198] In addition, in the motorcycle 500 of the present embodiment, the cam operating angle can be varied with a simple configuration without significantly changing the engine configuration to achieve high response and low fuel consumption in the engine. be able to. In addition, the motorcycle 500 has the most dynamic force and is stable at low vibrations even at high engine speeds when the engine 100 is prone to valve behavior that causes problems such as jamming and bounce. It is possible to run.

In the present embodiment, engine 100 is a single cylinder SOHC (Single Over Head Camshaft). This is not limited to this type, but is applicable to the multi-cylinder SOHC type and DOHC (Double Over Head Camshaft).

[0200] In this variable valve drive device 200, the rotational phase difference of the intake cam piece 240 is periodically changed with respect to the exhaust cam piece 220 that changes the working angle of the intake valve. Not limited to. That is, the rotational phase difference of the exhaust cam piece 220 may be periodically changed with respect to the intake cam piece 240. In this case, the variable valve driving device 200 is provided with an intake cam piece for driving the intake valve by rotating integrally with the cam sprocket 211, and an exhaust cam piece for driving the exhaust valve on the variable cam shaft 230. It is set as the structure which provided. With this configuration, it is possible to change the overlap by changing the working angle of the exhaust valve.

It can have the same operation effect.

[0201] The variable valve drive apparatus according to the first aspect of the present invention includes a cam drive member that is rotated by a drive force transmitted from a crankshaft, and a rotation shaft of the cam drive member that is driven by the cam drive member. An eccentric member that rotates about an axis in the same direction and that the shaft is movable to an axial center position force eccentric position of the rotary shaft, and is arranged coaxially with the rotary shaft, and is arranged by the eccentric member to A cam shaft that is rotationally driven about a rotation shaft and has a rotational phase difference with respect to the cam drive member periodically when the eccentric member is rotationally driven at the eccentric position; Rotate at the same rotational phase as, and open or close the exhaust valve or intake valve

A variable valve drive device including a cam piece to be driven, wherein a rotation speed detection unit that detects a rotation speed of the crankshaft, and a rotation speed of the crankshaft detected by the rotation speed detection unit; A control unit that moves the eccentric member and controls a position of the shaft of the eccentric member with respect to a rotation shaft of the cam drive member, and the control unit has a maximum rotational speed of the crankshaft or a maximum rotation of the crankshaft. A configuration is adopted in which the eccentric member is moved so that the position of the shaft of the eccentric member coincides with the axial position of the rotating shaft at a rotational speed close to a few.

[0202] According to this configuration, the engine having the maximum number of revolutions of the crankshaft or the number of revolutions near the maximum number of revolutions, that is, the maximum number of revolutions of the mounted engine or the number of revolutions around the maximum number of revolutions. At the time of high rotation, the position of the shaft of the eccentric member coincides with the shaft center position of the rotation shaft. This Therefore, the exhaust valve or the intake valve can be driven to open and close by rotating the cam piece that does not decenter the eccentric member at or near the maximum engine speed.

[0203] That is, since the eccentric member is not driven to rotate at the eccentric position at or near the maximum rotational speed of the engine, the cam piece has a rotational phase difference with respect to the cam driving member via the cam shaft. The fluctuation of the angular velocity of the exhaust valve or intake valve that is driven to open and close, which does not fluctuate periodically, is extremely small.

[0204] Therefore, a stable valve with low vibration at kinematics and high engine speed, which tends to cause problematic valve behavior, such as a jumble phenomenon and bounce phenomenon, in which large vibration is likely to occur due to inertial force. Behavior can be performed.

[0205] The variable valve driving device according to the second aspect of the present invention includes a cam driving member that rotates by a driving force transmitted from a crankshaft, and a rotating shaft of the cam driving member that is driven by the cam driving member. An eccentric member that rotates about an axis in the same direction and that the shaft is movable to an axial center position force eccentric position of the rotary shaft, and is arranged coaxially with the rotary shaft, and is arranged by the eccentric member to A cam shaft that is rotationally driven about a rotation shaft and has a rotational phase difference with respect to the cam drive member periodically when the eccentric member is rotationally driven at the eccentric position; A variable valve drive device that includes a cam piece that rotates at the same rotational phase as that of the exhaust valve and makes the operating angle of the exhaust valve or intake valve variable, and a rotational speed detector that detects the rotational speed of the crankshaft, A control unit that moves the eccentric member in accordance with the rotational speed of the crankshaft detected by the rotational speed detection unit and controls the position of the shaft of the eccentric member with respect to the rotational shaft of the cam drive member. When the control unit matches the position of the shaft of the eccentric member with the position of the axis of the rotary shaft, the working angle of the exhaust valve or the intake valve is maximized.

[0206] According to this configuration, the operating angle of the exhaust valve or the intake valve is maximized when the position of the shaft of the eccentric member coincides with the position of the shaft center of the rotating shaft. Therefore, the cam profile of the cam piece can be created based on the lift curve on the maximum operating angle side of the exhaust valve or the intake valve in a state where the exhaust valve or the intake valve does not have a periodic angular velocity fluctuation.

[0207] That is, when determining the cam profile of the cam piece, the exhaust valve or the intake valve is periodically The maximum without generating a negative radius of curvature (concave radius) compared to the case where there is no fluctuation in angular velocity and it is determined based on the lift curve on the low operating angle side of the exhaust valve or intake valve. Large valve lift.

[0208] Therefore, a cam piece capable of increasing the maximum output of the mounted engine can be set by using a conventional camshaft method for processing to have a convex radius. This makes it possible to set the cam profile of the cam piece that performs stable valve behavior with low vibration according to the engine speed.

[0209] Since the cam profile of the cam piece can be set in this way, the maximum rotational speed of the engine or the maximum inertial force in terms of kinematics, and the valve behavior that causes problems such as the jumping phenomenon and the bounce phenomenon are likely to occur. Even in the vicinity of the maximum speed, stable valve behavior can be achieved with low vibration.

[0210] Further, the variable valve drive apparatus according to the third aspect of the present invention includes a cam drive member that rotates by a drive force that also transmits a crankshaft force, and the force drive member that is driven by the cam drive member. An eccentric member that rotates about an axis in the same direction as the rotating shaft and that the shaft is movable to an eccentric position of the rotating shaft; and an eccentric member that is disposed coaxially with the rotating shaft, the eccentric member And a camshaft in which a rotation phase difference with respect to the cam drive member periodically varies when the eccentric member is rotationally driven at the eccentric position. A variable valve drive device that includes a cam piece that rotates at the same rotation phase as the cam shaft and makes the operating angle of the exhaust valve or intake valve variable, and that detects the rotation speed of the crankshaft. A control unit that moves the eccentric member in accordance with the rotation speed of the crankshaft detected by the rotation speed detection unit, and controls the position of the shaft of the eccentric member with respect to the rotation shaft of the cam drive member; And when the control unit makes the position of the shaft of the eccentric member coincide with the position of the shaft center of the rotating shaft at a substantially maximum rotational speed of the crankshaft, the action of the exhaust valve or the intake valve The corner has the maximum configuration.

[0211] According to this configuration, the operation of the aeration valve or the intake valve is substantially different at the substantially maximum rotational speed of the crankshaft, and the aspiration # or ^? Can be minimized. A variable valve driving device according to an aspect is the above-described configuration, wherein the cam By rotating about a rotation shaft that is substantially parallel to the rotation axis of the drive member and fixed to the engine side, the shaft of the eccentric member is coaxial with the rotation shaft of the cam drive member. An eccentric moving unit that is moved in the direction is provided, and the rotation of the eccentric moving unit is controlled by the control unit.

[0212] According to this configuration, the shaft of the eccentric member can be rotated only by rotating the eccentric moving portion around the rotation shaft that is substantially parallel to the rotation shaft of the cam drive member and fixed to the engine side. Thus, it can be appropriately moved to the eccentric position of the coaxial position force with respect to the rotation axis of the cam drive member.

[0213] In the variable valve drive device according to the fifth aspect of the present invention, in the configuration described above, the eccentric moving portion sandwiches the eccentric member with respect to the cam drive member in a rotation axis direction of the cam drive member. The rotating shaft of the eccentric moving part which is disposed to be opposed to the cam driving member is positioned inside the outer peripheral edge of the portion facing the eccentric moving part.

[0214] According to this configuration, the rotation shaft of the eccentricity moving unit is located inside the outer peripheral edge of the portion of the cam drive member that faces the eccentricity moving unit. For this reason, the entire variable valve drive device can be made compact without being located outward from the outer peripheral edge located in the radial direction in the mechanism force cam drive member that eccentrically moves the eccentric member.

[0215] In the above configuration, the variable valve drive device according to the sixth aspect of the present invention is configured such that the eccentric moving portion is inside the outer peripheral edge of a portion of the cam drive member facing the eccentric moving portion. The structure located in is taken.

[0216] According to this configuration, since the eccentric moving part is positioned inside the outer peripheral edge of the portion of the cam drive member that faces the eccentric moving part, the eccentric moving part together with the rotation shaft thereof is connected to the cam driving member. The outer peripheral edge located in the radial direction should not be located outward. In other words, the eccentric member and the eccentric moving part are arranged so as to overlap the cam driving member in the rotation axis direction of the cam driving member, and the entire variable valve driving device can be made compact.

[0217] The engine according to the seventh aspect of the present invention employs a configuration having the variable valve drive device configured as described above.

[0218] According to this configuration, the maximum rotational speed of the engine, in which the inertial force is the largest in terms of kinematics, and valve behavior that causes problems such as the phenomenon of jumping and the bounce phenomenon is likely to occur. Alternatively, stable driving can be performed with low vibration even in the vicinity of the maximum rotational speed.

[0219] The motorcycle according to the eighth aspect of the present invention employs a configuration in which the engine configured as described above is mounted.

[0220] According to this configuration, even with high engine speed, large vibrations occur due to kinematic inertial force, and valve behaviors such as jumping phenomenon and bounce phenomenon are likely to occur. Valve behavior can be performed stably.

Industrial applicability

[0221] The variable valve driving device according to the present invention has the largest inertial force in terms of kinematics, and is likely to cause valve behavior that causes problems such as a jumping phenomenon and a bounce phenomenon. It can perform stable valve behavior with low vibration and is useful as an engine and motorcycle.

Claims

The scope of the claims

[1] A cam driving member that rotates by a driving force transmitted from a crankshaft;

An eccentric member provided by the drive of the cam drive member so as to rotate about an axis in the same direction as the rotation axis of the cam drive member, and to move the shaft from an axial position of the rotation shaft to an eccentric position; ,

A rotational phase difference with respect to the force driving member when the eccentric member is rotationally driven around the rotational axis by the eccentric member and is rotationally driven around the rotational axis by the eccentric member. A camshaft that periodically fluctuates,

A variable valve driving device comprising: a cam piece that is rotated by the cam shaft at the same rotational phase as the cam shaft and that opens and closes an exhaust valve or an intake valve;

A rotational speed detector for detecting the rotational speed of the crankshaft;

A controller that controls the position of the shaft of the eccentric member relative to the rotational shaft of the cam drive member by moving the eccentric member according to the rotational speed of the crankshaft detected by the rotational speed detector; Have

The control unit moves the eccentric member at a maximum rotational speed of the crankshaft or a rotational speed in the vicinity of the maximum rotational speed, and sets the position of the shaft of the eccentric member to the axial position of the rotational shaft. A variable valve driving device characterized by matching with the above.

[2] a cam driving member that rotates by a driving force transmitted from the crankshaft;

A variable valve driving device comprising: a cam piece that is rotated by the cam shaft at the same rotational phase as the cam shaft, and that makes an operating angle of an exhaust valve or an intake valve variable;

According to the rotation speed of the crankshaft detected by the rotation speed detection section, the eccentric portion A control unit that moves the material and controls the position of the shaft of the eccentric member with respect to the rotation shaft of the cam drive member;

The variable valve driving device according to claim 1, wherein when the control unit makes the position of the shaft of the eccentric member coincide with the position of the shaft center of the rotating shaft, a working angle of the exhaust valve or the intake valve becomes maximum.

[3] a cam driving member that rotates by a driving force transmitted from the crankshaft;

When the control unit makes the position of the shaft of the eccentric member coincide with the position of the shaft center of the rotating shaft at the substantially maximum rotational speed of the crankshaft, the working angle of the exhaust valve or the intake valve is maximum. A variable valve driving device characterized by comprising:

[4] The shaft of the eccentric member is rotated with respect to the rotation shaft of the cam drive member by rotating about a rotation shaft that is substantially parallel to the rotation shaft of the cam drive member and fixed to the engine side. Equipped with an eccentric moving part that also moves the coaxial position force to the eccentric position,

4. The variable valve driving device according to claim 1, wherein the rotation of the eccentric moving unit is controlled by the control unit.

[5] The eccentric moving portion is disposed to face the cam drive member with the eccentric member interposed therebetween in a rotation axis direction of the cam drive member. 5. The variable valve driving device according to claim 4, wherein a rotation shaft of the eccentric moving part is located inside an outer peripheral edge of a portion of the cam driving member that faces the eccentric moving part.

6. The variable valve drive device according to claim 4, wherein the eccentric moving portion is located inside an outer peripheral edge of a portion of the cam drive member that faces the eccentric moving portion.

[7] An engine comprising the variable valve drive device according to any one of claims 1 to 3.

[8] A motorcycle equipped with the engine according to claim 7.