JP2005090455A - Valve system and internal combustion engine provided therewith - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a valve system and an internal combustion engine provided therewith, capable of always optionally varying the opening and closing timing, a valve lift quantity or a working angle of a valve. <P>SOLUTION: This valve system is constituted so that a lift characteristic of the valve 30 can be continuously varied by relative displacement of a three-dimensional cam 13 for continuously changing in the cam height and a cam working angle, and a valve lifter for advancing and retreating the valve 30 by being pressed to a cam surface of the three-dimensional cam 13. A swing arm 27 is interposed between a tappet of the valve lifter and the valve 30. The lift quantity and the lift timing of the valve 30 are varied in an optional relative displacement position between the three-dimensional cam 13 and the valve lifter, by changing the arm ratio in the swing arm 27. A tappet guide phase variable mechanism for changing a phase of a tappet guide 23, is arranged so as to vary the arm ratio of the swing arm 27. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a valve operating apparatus that variably controls a lift amount, a lift timing, and a working angle of a valve in accordance with an accelerator opening in an internal combustion engine in a motorcycle or an automobile.

  In recent internal combustion engines, a combination of variable phase and cam switching has started, and thereafter a valve operating system using a three-dimensional cam that continuously varies the working angle and lift amount has been proposed. For example, there is a type in which a follow-up mechanism for a change in contact angle is provided at the top of a direct hitting cylindrical tappet, and a valve lift amount is continuously variable by sliding a three-dimensional cam in the axial direction.

  This type of valve operating device has been developed which includes four intake / exhaust valves per cylinder and further has a mechanism for changing the operation timing of these valves. For example, the combustion efficiency is improved by variably controlling the cam phase on the intake side and changing the overlap amount with the exhaust side according to the engine speed.

  In such a conventional example, the valve opening / closing timing itself can be freely set in the entire rotation speed range, but the valve lift amount or the operating angle is limited to a predetermined one depending on the slide position of the cam. That is, there is a limit to the variable range of the valve lift amount at the same cam slide position.

  SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object thereof is to provide a valve operating apparatus and an internal combustion engine including the valve operating apparatus that can arbitrarily change the valve opening / closing timing, the valve lift amount, or the operating angle.

  The valve operating apparatus according to the present invention has a lift characteristic of the valve by relative movement of a three-dimensional cam in which a cam height and a cam working angle continuously change and a valve lifter that is pressed against the cam surface of the three-dimensional cam to advance and retract the valve. In which the swinging arm is interposed between the valve lifter tappet and the valve, and the arm ratio of the swing arm is changed to change between the solid cam and the valve lifter. The lift amount and lift timing of the valve can be varied at any relative movement position.

  Further, the valve operating apparatus of the present invention is characterized by having a tappet guide phase varying mechanism for changing the phase of the tappet guide so as to vary the arm ratio of the swing arm.

  Further, the valve gear of the present invention is characterized in that it has a swing arm holder phase varying mechanism for changing the phase of the swing arm holder so as to vary the arm ratio of the swing arm.

  Further, in the valve operating apparatus of the present invention, a valve timing continuous variable mechanism for changing the operation timing characteristics of the valve is provided, and the lift timing and the lift amount of the valve can be freely set at the same operating angle. And

  Moreover, in the valve operating apparatus of the present invention, the two valves are opened and closed by the single tappet, and the tappet has a self-aligning function so that the valve spring load of the two valves has a difference. Thus, the valve stroke amount in the vicinity of the low lift region is made different.

  In the valve gear of the present invention, the contact surface of the swing arm with the tappet is formed to have a predetermined radius of curvature centered on the axis of the camshaft.

  In the valve gear of the present invention, a contact surface of the tappet with the swing arm is formed to have a smaller radius of curvature than the contact surface of the swing arm.

  In the valve gear of the present invention, the center of curvature of the contact surface of the tappet is set so as to be biased to the opposite side of the swing trajectory of the swing arm with respect to the stroke locus of the tappet. And

  In the valve gear of the present invention, a contact surface of the swing arm with the valve shim is formed to have a predetermined radius of curvature centered on the axis of the camshaft.

  Further, in the valve gear of the present invention, the swing fulcrum of the swing arm is arranged outside the V bank set by the valve stem of the valve.

  Further, the internal combustion engine of the present invention is an internal combustion engine in which intake and exhaust are controlled by an intake valve and an exhaust valve, and is characterized in that any one of the above valve operating devices is provided on the intake side or the exhaust side. .

  According to the present invention, in this type of engine, the valve lift amount and the operating angle are variably controlled in accordance with the accelerator opening. In this case, a swing arm is inserted between the valve lifter tappet and the valve to change the arm ratio of the swing arm. As a result, the lift amount and lift timing of the valve can be varied at any relative movement position of the three-dimensional cam and the valve lifter. As described above, the valve lift amount can be variably controlled at the same slide position of the cam, so that it is possible to select or set the optimum valve lift amount and lift timing in the entire engine rotation range even in substantially the same output range. Become. This significantly improves fuel efficiency and exhaust gas performance.

Hereinafter, preferred embodiments of a valve gear according to the present invention and an internal combustion engine including the same will be described with reference to the drawings.
(First embodiment)
The valve gear according to the present invention can be effectively applied to various gasoline engines mounted on a motorcycle or a four-wheeled vehicle. In this embodiment, for example, as shown in FIG. To do.

  First, the overall configuration of the motorcycle 100 according to the present embodiment will be described. In FIG. 1, two front forks 103 supported by a steering head pipe 102 so as to be turnable to the left and right are provided at a front portion of a body frame 101 made of steel or an aluminum alloy material. A handle bar 104 is fixed to the upper end of the front fork 103, and grips 105 are provided at both ends of the handle bar 104. A front wheel 106 is rotatably supported on the lower portion of the front fork 103, and a front fender 107 is fixed so as to cover the upper portion of the front wheel 106. The front wheel 106 has a brake disc 108 that rotates integrally with the front wheel 106.

  A swing arm 109 is swingably provided at the rear portion of the vehicle body frame 101, and a rear shock absorber 110 is mounted between the vehicle body frame 101 and the swing arm 109. A rear wheel 111 is rotatably supported at the rear end of the swing arm 109, and the rear wheel 111 is rotationally driven via a driven sprocket 113 around which a chain 112 is wound.

  The engine unit 1 (solid line portion) mounted on the vehicle body frame 101 is supplied with an air-fuel mixture from an intake pipe 115 coupled to an air cleaner 114, and exhausted exhaust gas is exhausted through an exhaust pipe 116. The air cleaner 114 is installed in a large space behind the engine unit 1 and below the fuel tank 117 and the seat 118 in order to secure capacity. Therefore, the intake pipe 115 is coupled to the rear side of the engine unit 1, and the exhaust pipe 116 is coupled to the front side of the engine unit 1. A fuel tank 117 is mounted above the engine unit 1, and a seat 118 and a seat cowl 119 are connected to the rear of the fuel tank 117.

  Here, a drive motor for changing the tappet phase, which will be described later, is mounted on predetermined portions of the cylinder head 2 to the cylinder head cover 2a in the engine unit 1 (for example, the rear portion of the cylinder head cover 2a as shown in FIG. 1). The tappet phase varying drive motor is disposed so as not to interfere with the fuel tank 117 and other parts or members around the engine.

  The tappet phase variable drive motor can be installed either on the intake side or on the exhaust side if a link is used, but when it is provided on the exhaust side, the recess formed in the fuel tank 117 is exposed, and as such, the appearance deteriorates. Taking this into account, it is preferable to provide it on the intake side.

  Further, in FIG. 1, 120 is a headlamp, 121 is a meter unit including a speedometer, tachometer, or various indicator lamps, and 122 is a rearview mirror supported by the handlebar 104 via a stay 123. A main stand 124 is swingably attached to the lower part of the body frame 101, and the rear wheel 111 can be grounded or floated from the ground. The vehicle body frame 101 extends obliquely downward and rearward from the head pipe 102 provided at the front portion, and is bent so as to wrap under the engine unit 1, and then forms a pivot 109 a that is a shaft support portion of the swing arm 109. The tank rail 101a and the seat rail 101b are connected.

  The vehicle body frame 101 is provided with a radiator 125 in parallel with the vehicle body frame so as to avoid interference with the front fender 107, and a cooling water hose 126 is provided along the vehicle body frame 101 from the radiator 125, and an exhaust pipe 116. It communicates with the engine unit 1 without interfering with.

  2 is a side sectional view of the main part of the device of the present invention, FIG. 3 is a sectional view taken along the line AA in FIG. 2, and FIG. 4 is a sectional view taken along the line BB in FIG. In this embodiment, for example, a single-cylinder engine has two valves (that is, four valves) on the intake side (IN) and the exhaust side (EX) of the cylinder. In this embodiment, the present invention is applied to the intake side. However, the present invention can be applied only to either the intake side or the exhaust side. A cylinder head 2 is disposed on an upper part of a piston that reciprocates up and down in the cylinder, and a valve gear is accommodated in the cylinder head 2.

  In this embodiment, the cam side is slid in order to change the relative position in the camshaft axial direction between the cam and the camshaft. However, the valve lift characteristics can be improved by moving either the cam side or the camshaft side. It can be continuously variable.

  The valve gear controls the cam / camshaft unit that is arranged along the vehicle width (left and right) direction, the valve lifter unit that is pushed by the cam surface of the cam in the cam / camshaft unit, and controls intake and exhaust. And a swing arm mechanism interposed between the tappet of the valve lifter unit and the valve.

  First, in the cam / camshaft unit, the camshaft 11 is rotatably supported by the cylinder head 2 via a metal bearing 12. A cam 13 is slidably mounted on the camshaft 11 in the axial direction. In this example, the camshaft 11 has, for example, three ball splines 11a, and the cam 13 is linearly connected via the balls 14 by the guide. It is designed to move (linear motion). The camshaft 11 typically has a hollow structure, and a lubricating oil passage can be formed inside the hollow to lubricate the bearing portion and the like.

A sprocket 15 is fixed to one end of the camshaft 11 via a variable valve timing mechanism described later. A similar sprocket 15 _Ex is fixed to one end of the camshaft 11 _Ex on the exhaust side, and as shown in FIG. 5, the drive is fixed to one end of these sprockets 15 and 15 _Ex and a crankshaft (not shown). A cam chain 4 is wound around the sprocket 3. In addition, as shown in FIG. 5, the chain guide 5, the chain tensioner 6, the tensioner adjuster 7, etc. are included so that the cam chain 4 can travel properly.

  Here, the cams 13 are three-dimensionally configured as so-called “three-dimensional cams”, and are provided one by one on the intake side and the exhaust side of the cylinder. The cam surface that is gently inclined in the longitudinal direction (the axial direction of the camshaft 11) is formed into a shape that continuously changes the valve lift amount. In this case, the cam operating angle and the lift timing change simultaneously with the cam height, that is, the cam operating angle increases as the valve lift amount increases, and the valve lift timing can also be changed. By slidably moving the valve lifter unit with respect to such a cam 13, the lift amount, operating angle, and lift timing of the intake valve and the exhaust valve can be variably controlled steplessly.

  Further, in addition to the slide mechanism of the cam 13, a cam timing changing mechanism is added to one end of the cam shaft 11. The variable valve timing mechanism 16 (for example, referred to as “VVT mechanism” or the like) can vary the rotational direction phase of the camshaft 11 using hydraulic pressure, and can vary the valve timing and tappet guide phase. And a variable timing adjustment function.

According to the variable valve timing mechanism 16, the cam timing can be changed effectively without increasing the size of the apparatus and increasing the cost. For changing the cam timing, the cam phase sensor 17 (FIG. 3) can be used effectively because the camshaft 11 itself does not slide. The cam phase sensor 17 detects the pin 18 planted on the other end side of the camshaft 11 and detects the phase of the cam 13.
A sprocket phase sensor 19 for detecting the phase of the sprocket 15 is provided at an appropriate position of the cylinder head cover 2a.

One end of the exhaust-side camshaft 11 _Ex is rotatably supported by a bearing 20. The exhaust cam / camshaft unit has the same basic configuration as the intake cam / camshaft unit, but the specific specifications of the cam 13 _EX are different from those of the cam 13.

  As shown in FIG. 3, the intake-side valve lifter unit includes a tappet roller 21 having a spherical outer peripheral surface, and the outer peripheral surface contacts the cam 13. In addition, you may make thin one side part which does not contact the cam 13 among the outer peripheral surfaces of the tappet roller 21 for the purpose of weight reduction. An arm member 22 is disposed in the tappet roller 21. The inner peripheral surface of the tappet roller 21 is a spherical surface, and a ball 24 is interposed between the inner peripheral surface and the large diameter portion at the center of the arm member 22. Therefore, the tappet roller 21 is rotatably supported via the ball 24 and the arm member 22 is swingable. Even when the arm member 22 is tilted with respect to the tappet roller 21, the centering function that allows the tappet roller 21 to rotate normally is exhibited.

  A tappet guide 23 is disposed so as to cover the arm member 22. The tappet guide 23 includes a guide portion 23a for guiding the tappet roller 21, a support portion 23b supported by the cylinder head 2 so as to be rotatable concentrically outside the camshaft 11, and a drive gear operated by a drive motor described later. And a gear portion 23c that meshes with. A drive motor 25 for variably controlling the phase of the tappet guide 23 is mounted on the cylinder head 2 to the cylinder head cover 2a, and a drive gear 26 provided on the output shaft thereof meshes with the gear portion 23c. . These members constitute a tappet guide phase varying mechanism that changes the phase of the tappet guide 23.

  A swing arm 27 is inserted between the tappet and the valve, that is, between the arm member 22 and the tappet shim. By changing the arm ratio of the swing arm 27, the lift amount and lift timing of the valve can be varied at an arbitrary relative position between the cam 13 and the valve lifter. In this example, the arm ratio of the swing arm 27 is varied by changing the phase of the tappet guide 23 by the tappet guide phase varying mechanism. As shown in FIG. 6, the swing arm 27 is rotatable around a swing arm shaft 29 supported by a bearing boss 28. In this case, the swing arm shaft 29 (the swing fulcrum of the swing arm 27) is disposed outside the V bank set by the valve stem of the valve. A pair of swing arms 27 that can be individually operated are provided on the pressing portions 22a at both ends of the arm member 22. Note that a relief 28a with respect to the tappet guide 23 is formed in the central bearing boss 28 (FIG. 2).

  The contact surface of the swing arm 27 with the tappet (the pressing portion 22a of the arm member 22) is formed to have a predetermined radius of curvature R centered on the axis of the camshaft 11 as shown in FIG. The contact surface of the tappet pressing portion 22 a with the swing arm 27 is formed to have a smaller radius of curvature r than the contact surface of the swing arm 27.

  In the valve unit on the intake side, as shown in FIGS. 2 and 3, the valve stem 30 a includes two intake valves 30 guided by a valve guide 31. When the intake valve 30 is lifted, a mixture of air guided from the air cleaner 114 via the intake port 32 and fuel sprayed from the injector 33 disposed on the downstream side of the intake port 32 is introduced into the combustion chamber. .

  A valve retainer 34 is provided at the end of each valve stem 30a, and a valve spring 36 mounted between the valve retainer 34 and the valve seat 35 applies an elastic force. Further, a tappet shim 37 is attached to the upper end opening of the valve retainer 34, and is pressed by the pressing portion 22 a of the arm member 22 through the tappet shim 37.

The exhaust-side valve lifter unit and the valve unit have the same basic configuration as the intake-side valve unit 30 as shown in FIGS. In this case, the arm member 22 _EX of the tappet roller 21 _EX is adapted to actuate the exhaust valve 30 _EX via the direct valve retainer 34 _EX.

In the accelerator shaft unit, as shown in FIG. 2 or FIG. 4, an accelerator shaft 38 disposed in parallel between the cam shafts 11 and 11 _EX , and an accelerator fixed to the accelerator shaft 38 and connected to the cams 13 and 13 _EX. Fork 39 is provided.

  The accelerator shaft 38 is supported so as to be slidable in the axial direction, and is engaged with a driven gear 40 (bevel gear) via a feed screw 38a on one end side. The driven gear 40 is rotatably supported by the cylinder head 2 and meshes with a drive gear 42 (bevel gear) fixed to the output shaft of the accelerator motor 41 as shown in FIG.

As shown in FIG. 4, the accelerator fork 39 extends toward the camshafts 11 and 11 _{EX in a} direction orthogonal to the accelerator shaft 38 and has a bifurcated tip. Further, fork guides 44 and 44 _EX that are rotatable via bearings 43 and 43 _EX are provided at the ends of the cams 13 and 13 _EX . Each bifurcated tip of the accelerator fork 39 engages with an engagement groove of the fork guides 44 and 44 _EX and is movable along the engagement groove. As a result, the cams 13 and 13 _EX slide along the cam shafts 11 and 11 _EX in synchronization with or in synchronization with the accelerator shaft 38 sliding in the axial direction.

Here, when the accelerator grip (or the accelerator pedal) is operated in the above configuration, the accelerator motor 41 is operated, and the accelerator shaft 38 is slid through the driven gear 40 by the rotation of the output shaft of the accelerator motor 41. The cams 13 and 13 _EX slide along the cam shafts 11 and 11 _EX via the accelerator fork 39 in conjunction with the movement of the accelerator shaft 38. In this embodiment, the valve lift amount and the operating angle are variably controlled in accordance with the accelerator opening not only on the intake side but also on the exhaust side.

In this way, intake / exhaust that is most suitable for the engine speed (or vehicle speed) can be performed by controlling the intake air amount and the exhaust air amount from the idle rotation region to the fully open region. For example, when the engine speed is low, the tappet rollers 21 and 21 _EX come into contact with the cam surface of the cams 13 and 13 _EX at a relatively low cam height. When acceleration is performed in this state, that is, the accelerator is opened, the driven gear 40 is rotated by the operation of the accelerator motor 41, and the accelerator shaft 38 slides in the right direction in FIG. The cams 13 and 13 _EX slide in the same manner along the cam shafts 11 and 11 _EX in conjunction with the movement of the accelerator shaft 38 via the accelerator fork 39. As the cams 13 and 13 _EX slide, the tappet rollers 21 and 21 _EX gradually come into contact with a relatively high cam portion, and the valve lift increases. On the other hand, by returning the accelerator at the time of deceleration, the valve lift amount is reduced by the reverse operation to the above.

In particular, in the present invention, the arm ratio of the swing arm 27 is varied by changing the phase of the tappet guide 23 by the tappet guide phase varying mechanism, whereby the valve lift amount can be variably controlled at the same slide position of the cam 13. . In this case, the drive motor 25 is driven and controlled, and the phase α (see FIG. 2) of the tappet guide 23 is changed through the engagement of the drive gear 26 and the gear portion 23c. As shown in FIG. 2, the pressing portion 22a of the arm member 22 contacts the swing arm 27 at a position where the arm ratio of the swing arm 27 is maximum (arm ratio 1 or more) at the phase α _max and swings at the phase α _min. The arm 27 comes into contact with the swing arm 27 at a position where the arm ratio becomes the minimum (arm ratio 1 or less).

Thus, the valve lift amount can be arbitrarily varied by changing the arm ratio of the swing arm 27 at the same slide position of the cam 13. Note that the phase of the tappet guide 23 is limited in the range of α _{min to} α _max , but a variable range of about twice is secured in the illustrated example of FIG.

  In addition, by using the variable valve timing mechanism 16 together, the lift timing is adjusted so as not to change with the change of the tappet stroke phase by the tappet guide phase changing mechanism, and the lift timing is variably controlled by changing the adjustment amount. can do.

  It should be noted that, in a valve operating apparatus equipped with this type of cam slide mechanism, even when a VVT mechanism or the like is used in combination, basically only the valve lift timing can be freely set at the same slide position of the cam. On the other hand, according to the present invention, the valve lift amount can be variably controlled at the same slide position of the cam 13, so that the optimum valve lift amount and It becomes possible to select or set the lift timing. As a result, fuel efficiency and exhaust gas performance are greatly improved.

  The operating angle can be set to the same output (torque) as the slide position before adjustment by adjusting the valve lift amount and the lift timing at a position where the cam 13 is slightly shifted, and the valve overlap. The amount can be set freely. As a result, the lift characteristics can be freely set over the entire engine speed, so that it is always possible to select a lift characteristic that matches the output (torque) and the speed.

  Further, the valve lift amount can be increased by setting the arm ratio of the swing arm 27 to 1 or more than in the case of the direct hitting valve lifter. Thus, the amount of valve lift caused by the cam lobe itself of the cam 13 can be relatively reduced by the amount that the valve lift amount can be increased, and the cam crest inclination angle along the sliding direction of the cam lobe can be set small. As a result, the tappet roller 21 (spherical contact) is made smaller and the weight of the reciprocating motion part is reduced, so that an increase in weight due to the swing arm 27 can be offset and the slide stroke of the cam 13 can be shortened. Therefore, the width of the cylinder head 2 can be substantially reduced.

In addition, the two intake valves 30 are driven to open and close by a single tappet roller 21, and the tappet roller 21 has an automatic alignment function (the same applies to the exhaust side). In this case, in particular, a difference can be given to the spring load of the valve springs 36 of the two intake valves 30, so that the valve stroke amount in the vicinity of the low valve lift region can be set different.
For example, in the lowest valve lift region, by setting one of the two intake valves 30 to a resting state, the turbulence performance and the intake inflow speed are improved, fuel efficiency and exhaust gas performance are improved, and lean burn can be achieved. In the vicinity of the low-medium valve lift region, there is a difference in the valve lift amount (especially, the valve opening start), so that the turbulence is increased and the output and fuel efficiency are improved.

  Further, the contact surface of the swing arm 27 with the tappet has a predetermined radius of curvature R around the axis of the camshaft 11 when the valve lift is zero. By forming the contact surface of the swing arm 27 in this way, the swing arm 27 is prevented from being lifted at the zero lift timing when the tappet guide phase is variable.

  Further, the contact surface of the tappet (the pressing portion 22 a of the arm member 22) with the swing arm 27 has a smaller radius of curvature than the contact surface of the swing arm 27. By forming the contact surface of the pressing portion 22a in this way, the end of the pressing portion 22a is prevented from coming into contact with the swing arm 27, thereby improving durability.

Further, the swing fulcrum (swing arm shaft 29) of the swing arm 27, the intake valve 30 and the exhaust valve 30 _EX of the valve stem 30a, are arranged in a V bank outside set by 30a _EX. By arranging the swing arm shaft 29 in this way, the swing arm shaft 29 can be arranged without being affected by the plug hole, and the V bank can be set at a narrow angle accordingly.

(Second Embodiment)
Next, a second embodiment of the valve gear according to the present invention will be described.
9 is a cross-sectional side view of a main part of a valve gear according to a second embodiment of the present invention, FIG. 10 is a cross-sectional view taken along line FF in FIG. 9, and FIG. 11 is taken along line GG in FIG. It is sectional drawing. The basic configuration in this embodiment is substantially the same as that of the first embodiment described above, and the same reference numerals are used for the same or corresponding members.

  Also in the second embodiment, the valve operating apparatus includes a cam / camshaft unit disposed along the vehicle width (left-right) direction, and a valve lifter that moves the valve forward and backward by being pushed by the cam surface of the cam in the cam / camshaft unit. Unit, valve unit that controls intake and exhaust, accelerator shaft unit that slides the cam in the axial direction of the camshaft according to the accelerator opening, and swing arm mechanism inserted between the tappet and valve of the valve lifter unit Including.

  In the second embodiment, the tappet guide 45 is fixedly disposed at an appropriate position of the cylinder head 2 on the intake side, that is, between the two intake valves 30. An arm member 22 is disposed in the tappet roller 21. The inner peripheral surface of the tappet roller 21 is a spherical surface, and a ball 24 is interposed between the inner peripheral surface and the large diameter portion at the center of the arm member 22. Therefore, the tappet roller 21 is rotatably supported via the ball 24 and the arm member 22 is swingable. Even when the arm member 22 is tilted with respect to the tappet roller 21, the centering function that allows the tappet roller 21 to rotate normally is exhibited.

  A swing arm 46 is inserted between the tappet and the valve, that is, between the arm member 22 and the tappet shim 37. The swing arm 46 is held by a swing arm holder 47. By changing the arm ratio of the swing arm 46 via the swing arm holder 47, the lift amount and the lift timing of the valve can be adjusted at an arbitrary relative position between the cam 13 and the valve lifter. It is made variable.

  The swing arm holder 47 is supported by the cylinder head 2 so as to be rotatable concentrically outside the camshaft 11 (see FIG. 10 and FIG. 11), and the drive gear 26 operated by the drive motor 25. The gear part 47b which meshes is provided. Also in this example, the cylinder head 2 to the cylinder head cover 2a are equipped with the drive motor 25 for variably controlling the phase of the swing arm holder 47 so that the drive gear 26 provided on the output shaft meshes with the gear portion 47b. It has become. These members constitute a swing arm holder phase variable mechanism that changes the phase of the swing arm holder 47.

  As shown in FIG. 10, a swing arm 46 is provided for each of the two intake valves 30. In this case, as shown in FIG. 12, each swing arm 46 is rotatably supported by a swing arm shaft 48 press-fitted and fixed to a swing arm holder 47. A swing arm shaft 48 that is a swing fulcrum of the swing arm 46 is disposed outside the V bank set by the valve stem of the valve (see FIG. 9).

Here, the contact surface between the tappet (pressing portion 22a of the arm member 22) of the swing arm 46, so as to have a predetermined radius of curvature R ₁ centered on the axis of the camshaft 11 as shown in FIG. 9 It is formed. The contact surface of the tappet pressing portion 22a with the swing arm 46 is formed to have a smaller radius of curvature r than the contact surface of the swing arm 46. In this case, the center of curvature Or of the contact surface of the pressing portion 22a is appropriately deviated (offset amount S) on the opposite side of the swing trajectory (swing arm shaft 48) of the swing arm 46 from the stroke trajectory of the tappet. Is set.

The contact surface of the swing arm 46 with the valve (tapet shim 37) is formed to have a predetermined radius of curvature R ₂ (> R ₁ ) centered on the axis of the camshaft 11 as shown in FIG. . Further, the top portion of the tappet shim 37 of the intake valve 30 (contact surface with the swing arm 46) is formed in a spherical shape.

Also in the second embodiment, when the accelerator grip (or accelerator pedal) is operated, the accelerator motor 41 is operated, and the accelerator shaft 38 slides through the driven gear 40 by the rotation of the output shaft of the accelerator motor 41. The cams 13 and 13 _EX slide along the cam shafts 11 and 11 _EX via the accelerator fork 39 in conjunction with the movement of the accelerator shaft 38. In this embodiment, the valve lift amount and the operating angle are variably controlled in accordance with the accelerator opening on the exhaust side as well as on the intake side.

In particular, in this embodiment, by changing the phase of the swing arm holder 47 by the swing arm holder phase varying mechanism, the arm ratio of the swing arm 46 is varied, thereby variably controlling the valve lift amount at the same slide position of the cam 13. be able to. In this case, the drive motor 25 is driven and controlled, and the phase α (see FIG. 9) of the swing arm holder 47 is changed through the engagement of the drive gear 26 and the gear portion 47b. As shown in FIG. 9, the pressing portion 22a of the arm member 22 is in contact with the swing arm 46 at a position where the arm ratio of the swing arm 46 is maximum at the phase α _max , and the arm ratio of the swing arm 46 is at phase α _min. The swing arm 46 is contacted at a position where the position is minimized.

  Thus, the valve lift amount can be arbitrarily varied by changing the arm ratio of the swing arm 46 at the same slide position of the cam 13. In particular, in the second embodiment, the valve lift amount can be varied with the same valve operating angle without deviating the preset timing without using a VVT mechanism or the like.

  On the other hand, by using the variable valve timing mechanism 16 together, the lift timing is adjusted so that the lift timing does not change in accordance with the change of the tappet stroke phase by the tappet guide phase variable mechanism, and the lift timing can be changed by changing the adjustment amount. Can be controlled.

  Since the valve lift amount can be variably controlled at the same slide position of the cam 13 as described above, the optimum valve lift amount and lift timing are selected or set in the entire engine rotation range even in substantially the same output (torque) region. It becomes possible. As a result, fuel efficiency and exhaust gas performance are greatly improved.

  The operating angle can be set to the same output (torque) as the slide position before adjustment by adjusting the valve lift amount and the lift timing at a position where the cam 13 is slightly shifted, and the valve overlap. The amount can be set freely. As a result, the lift characteristics can be freely set over the entire engine speed, so that it is always possible to select a lift characteristic that matches the output (torque) and the speed.

Further, it is possible to make a difference in the spring load of the valve spring 36 of the two intake valves 30 and thereby set the valve stroke amount in the vicinity of the low valve lift region to be different.
For example, in the lowest valve lift region, by setting one of the two intake valves 30 to a resting state, the turbulence performance and the intake inflow speed are improved, fuel efficiency and exhaust gas performance are improved, and lean burn can be achieved. In the vicinity of the low-medium valve lift region, there is a difference in the valve lift amount (especially, the valve opening start), so that the turbulence is increased and the output and fuel efficiency are improved.

Further, the contact surface of the swing arm 46 with the tappet and the valve is formed to have a predetermined radius of curvature R ₁ or R ₂ centering on the axis of the camshaft 11 when the valve lift amount is zero. By forming the contact surface of the swing arm 46 as described above, the swing arm holder 47 is prevented from being lifted at the zero lift timing when the phase of the swing arm holder 47 is varied.

  Further, the contact surface of the tappet (the pressing portion 22 a of the arm member 22) with the swing arm 46 has a smaller radius of curvature than the contact surface of the swing arm 46. By forming the contact surface of the pressing portion 22a in this way, the end of the pressing portion 22a is prevented from coming into contact with the swing arm 46, thereby improving the durability.

  Further, the curvature center Or of the contact surface of the pressing portion 22a in the tappet is set so as to be appropriately deviated from the tappet stroke locus on the opposite side to the swing fulcrum (swing arm shaft 48) of the swing arm 46. Since the amount of movement of the contact point between the swing arm 46 and the tappet can be increased, the radius of curvature of the swing arm 46 can be increased by that amount, so that the Hertz stress can be reduced. As a result, the durability is improved, the contact is made compact, and the weight of the reciprocating portion is reduced, thereby enabling high rotation.

As mentioned above, although this invention was demonstrated with various embodiment, this invention is not limited only to these embodiment, A change etc. are possible within the scope of the present invention.
For example, the specific numerical examples described in the above embodiment are not necessarily limited to this, and can be changed as necessary. In each embodiment, an example of a single cylinder engine has been described. However, the present invention can be effectively applied to a multi-cylinder engine having two or more cylinders.

It is a figure which shows the structural example of the motorcycle containing the engine periphery which concerns on the example of application of this invention. It is principal part side sectional drawing of the valve operating apparatus in the 1st Embodiment of this invention. It is sectional drawing which follows the AA line of FIG. It is sectional drawing which follows the BB line of FIG. It is a figure which shows the crankshaft drive system which concerns on the valve gear of this invention. It is sectional drawing which follows the CC line of FIG. It is sectional drawing which follows the DD line | wire of FIG. It is sectional drawing which follows the EE line | wire of FIG. It is principal part sectional drawing of the valve operating apparatus in the 2nd Embodiment of this invention. It is sectional drawing which follows the FF line | wire of FIG. It is sectional drawing which follows the GG line of FIG. It is sectional drawing which follows the HH line of FIG.

Explanation of symbols

1 Engine unit 2 Cylinder head 3 Drive sprocket 4 Cam chain 5 Chain guide 5
6 Chain tensioner 7 Tension adjuster 11 Cam shaft 13 Cam 15 Sprocket 16 Variable valve timing mechanism 17 Cam phase sensor 21 Tappet roller 22 Arm member 23 Tappet guide 25 Drive motor 26 Drive gear 27 Swing arm 29 Swing arm shaft 30 Intake valve 32 Intake port 34 Valve retainer 36 Valve spring 37 Tappet shim 38 Accelerator shaft 39 Accelerator fork 40 Driven gear 41 Accelerator motor

Claims (11)

A movement in which the lift characteristics of the valve are continuously variable by relative movement between a three-dimensional cam whose cam height and cam working angle continuously change and a valve lifter which is pressed against the cam surface of the three-dimensional cam and advances and retracts the valve. A valve device,
By inserting a swing arm between the valve lifter tappet and the valve and changing the arm ratio of the swing arm, the lift amount and lift of the valve at any relative movement position between the three-dimensional cam and the valve lifter A valve operating device characterized in that the timing is variable.   2. The valve operating apparatus according to claim 1, further comprising a tappet guide phase changing mechanism that changes a phase of the tappet guide so as to change an arm ratio of the swing arm.   2. The valve operating apparatus according to claim 1, further comprising a swing arm holder phase varying mechanism that varies a phase of the swing arm holder so as to vary an arm ratio of the swing arm.   The valve timing continuous variable mechanism for changing the operation timing characteristic of the valve is provided, and the lift timing and the lift amount of the valve can be freely set at the same operating angle. 2. The valve gear according to item 1.   The two tap valves are driven to open and close by the single tappet, and the tappet has a self-aligning function. By providing a difference in the valve spring load of the two valves, the valve stroke amount in the vicinity of the low lift region is obtained. The valve operating device according to any one of claims 1 to 4, wherein the valve units are different from each other.   The contact surface of the swing arm with the tappet is formed to have a predetermined radius of curvature centered on the axis of the camshaft. Valve gear.   The valve operating device according to claim 6, wherein a contact surface of the tappet with the swing arm is formed to have a smaller radius of curvature than the contact surface of the swing arm.   8. The valve operating valve according to claim 7, wherein the center of curvature of the contact surface of the tappet is set so as to deviate from the stroke locus of the tappet on the opposite side with respect to the swing fulcrum of the swing arm. apparatus.   The valve operating device according to claim 6, wherein a contact surface of the swing arm with the valve shim is formed to have a predetermined radius of curvature centering on an axis of the camshaft.   10. The valve operating apparatus according to claim 1, wherein a swing fulcrum of the swing arm is disposed outside a V bank set by a valve stem of the valve. An internal combustion engine configured to control intake and exhaust by an intake valve and an exhaust valve,
An internal combustion engine comprising the valve gear according to any one of claims 1 to 10 on an intake side or an exhaust side.

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