JP2003003812A - Valve mechanism and internal combustion engine equipped with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a valve mechanism, which makes the optimizing control of a valve with adequate and smooth motion and exerts the excellent effect in the fuel improvement, and an internal combustion engine equipped with the same. SOLUTION: The valve mechanism has a camshaft 11, valve lifters 21, 22 in the shape of almost a disc, advancing and retreating with cams 13, 14 of the camshaft 11, and a locker arm 41, which is free to slide and swing with the valve lifters 21, 22, and the valve is advanced and retreated by swinging of the locker arm 41. The valve lifter 21, 22 are relatively movably held around the camshaft 11 by a valve lifter holding member 24. Revolving the valve lifter holding member 24 corresponding to an axle opening can change the sliding position of the locker arm continuously and infinitely variably.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve operating system for variably controlling a lift amount, a lift timing and a working angle of a valve in an internal combustion engine of a motorcycle, an automobile or the like according to an accelerator opening.

[0002]

2. Description of the Related Art In this type of internal combustion engine, various ideas and proposals have been made to improve the combustion efficiency. Beginning with the variable phase method that shifts the opening and closing timing of the valve, variable control of valve lift by cam switching and valve suspension have been adopted. In this cam switching system, two cams for low speed and high speed are prepared and the cam having a smaller working angle is switched to the one having a larger working angle according to the engine output.

More recently, a combination of variable phase and cam switching has begun to appear, and thereafter, a system using a three-dimensional cam for continuously varying the working angle and the lift amount has been proposed. For example, there is a direct tapping type cylindrical tappet which is provided with a follow-up mechanism for a change in contact angle and which slides a three-dimensional cam in the axial direction to continuously change the valve lift amount.

On the other hand, as the rocker type, for example, a variable valve device disclosed in Japanese Patent Laid-Open No. 11-107725, which has a swing cam, is known. This valve operating device has a drive shaft integrally provided with a ring-shaped drive cam on the outer periphery, a rocker arm having one end connected to the drive cam and the other end connected to a swing cam via a link arm and a link member. The rocking arm transmits the pressing force of the rocker arm transmitted by the rotation of the drive cam to the intake valve via the valve lifter.

[0005]

However, in the conventional device as described in the above publication, the structure is complicated, and wear and seizure of each member are likely to occur, and there is a problem in durability. Also,
Since the cost is high and the peak of the lift curve of the drive cam is sharp, there is a problem that a so-called jump is likely to occur during the intermediate lift.

Alternatively, in another rocker system, that is, a rocker fulcrum swing type, there is no change in valve timing, so a variable valve timing mechanism is not required, but the fulcrum swings, so rattling or misalignment at the fulcrum. Is easily generated. Therefore, it is necessary to increase the rigidity of the fulcrum swing arm, in which case the weight tends to be heavy, and the driving force must be increased.

Further, in the rocker fulcrum slide type, the mechanism for regulating the slide amount of the fulcrum is complicated,
The rattling of those parts overlaps and becomes the rattling of the fulcrum. Therefore, accuracy and rigidity of each part are required, and there is a problem that weight and cost increase.

In view of the above situation, it is an object of the present invention to provide a valve operating device that optimally controls a valve by proper and smooth operation and exhibits an excellent effect such as improvement of fuel consumption, and an internal combustion engine equipped with the valve operating device. .

[0009]

DISCLOSURE OF THE INVENTION A valve operating system of the present invention comprises a camshaft, a substantially disk-shaped valve lifter that is moved forward and backward by a cam of the camshaft, and a rocker capable of sliding contact with the valve lifter and swinging. A valve operating device having an arm and moving the valve forward and backward by swinging the rocker arm, wherein the valve lifter is held by a valve lifter holding member so as to be relatively movable around the cam shaft, and an accelerator opening is performed. By rotating the valve lifter holding member in accordance with the degree, the sliding contact position with the rocker arm can be continuously and continuously changed.

Further, in the valve train of the present invention, at least one valve lifter for high lift and one valve lifter for low lift are provided for each cylinder, and these valve lifters are mounted on the valve lifter holding member so as not to slide on the rocker arm at the same time. And a predetermined phase difference is set.

Further, in the valve gear of the present invention, the camshaft is controlled so as to be movable in the circumferential direction relative to the driven sprocket of the cam chain according to the accelerator opening.

Further, in the valve gear of the present invention, the valve lifter is forcibly moved in a direction away from the cam surface when the sliding contact with the cam is not selected.

Further, in the valve operating system of the present invention, the valve lifter is always urged radially outward of the camshaft by the elastic member, while the valve lifter holding member is substantially U at a position corresponding to each valve lifter. A U-shaped groove is formed, and the U-shaped groove opens inward in the radial direction of the camshaft.

Further, in the valve operating apparatus of the present invention, the valve lifter holding member pivotally supports the valve lifter in a substantially U-shaped groove provided at a position corresponding to each valve lifter, and the valve lifter is provided along the U-shaped groove. The valve lifter holding fork covering a part of the valve lifter holding member is formed in a substantially arc shape while holding the valve lifter forward and backward, and an opening and an inclined surface are formed in the inner peripheral side bottom surface portion of the valve lifter holding fork. The valve lifter is configured to be able to ride on the inclined surface and the bottom surface of the.

In the valve train of the present invention, the low lift valve lifter is slidably in contact with one rocker arm, and the high lift valve lifter is slidably in contact with one and the other rocker arms. Characterize.

Further, in the valve gear of the present invention, a set of a low lift valve lifter and a high lift valve lifter is provided so as to be capable of sliding contact with one rocker arm, and the high lift valve lifter is provided separately from the high lift valve lifter. Is arranged so as to be capable of sliding contact with the other rocker arm.

Further, in the valve train of the present invention, a plurality of valve lifters having different lift amounts for at least a low lift and a high lift are provided for each valve.

Further, in the valve gear of the present invention, the camshaft is controlled so as to be relatively movable in the circumferential direction by increasing or decreasing the hydraulic pressure.

Further, in the valve operating system of the present invention, the camshaft is controlled so as to be mechanically movable in the circumferential direction in synchronization with the switching of the valve lifter.

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 at least the intake side is equipped with any one of the above valve operating devices. And Further, the internal combustion engine of the present invention includes a steering head pipe that pivotally supports a front fork, a fuel tank mounted on a vehicle body frame that is connected to the steering head pipe, and a fuel tank that is connected behind the fuel tank. In a motorcycle having a seat and an air cleaner arranged below the seat and the fuel tank, an intake pipe mounted in front of the air cleaner and connecting the rear part and the air cleaner to the intake pipe are connected to each other. An internal combustion engine having an exhaust pipe connected to the opposite side of the camshaft, a substantially disk-shaped valve lifter that moves back and forth by a cam of the camshaft, and slidable contact and swingable with the valve lifter. A rocker arm, and a valve operating device for advancing and retracting a valve by rocking the rocker arm. The valve lifter is held by a valve lifter holding member so as to be relatively movable around the camshaft, and the valve lifter holding member is rotated in accordance with an accelerator opening degree so that a sliding contact position with the rocker arm is maintained. It is characterized by being able to change continuously and steplessly.

According to the present invention, in its typical embodiment, the valve lifter is held so as to be relatively movable around the cam shaft by the valve lifter holding member. By rotating the valve lifter holding member according to the accelerator opening, the sliding contact position with the rocker arm can be changed continuously and steplessly. As a result, the lift amount and lift timing of the intake valve can be continuously varied, and the valve working angle can be variably controlled stepwise.
In this case, the valve lift can be switched at the optimum timing in the low speed range and the medium and high speed range, and the valve lift amount can be smoothly and properly controlled in a wide range from the idling speed range to the maximum speed range to improve fuel consumption and output. .

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a main part (around a cylinder head) of an engine equipped with a valve operating system according to the present invention. The present invention can be effectively applied to various gasoline engines mounted on a motorcycle or a four-wheeled vehicle, and in this embodiment, a motorcycle engine is taken as an example as shown in FIG.

First, the overall structure of the motorcycle 100 according to this embodiment will be described. In FIG. 2, two front forks 103 supported by a steering head pipe 102 to be rotatable left and right are provided on a front portion of a vehicle body frame 101 made of steel or an aluminum alloy material.
Is provided. A handlebar 104 is fixed to the upper end of the front fork 103, and grips 105 are provided at both ends of the handlebar 104. A front wheel 106 is rotatably supported on the lower portion of the front fork 103, and
The front fender 107 covers the upper portion of the front wheel 106.
Is fixed. 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 body frame 101, and a rear shock absorber 110 is mounted between the body frame 101 and the swing arm 109. Swing arm 10
A rear wheel 111 is rotatably supported at the rear end of the rear wheel 9.
11 is rotationally driven via a driven sprocket 113 around which a chain 112 is wound.

The engine 1 (solid line portion) mounted on the vehicle body frame 101 is supplied with an air-fuel mixture from an intake pipe 115 connected to an air cleaner 114, and exhaust gas after combustion is exhausted through an exhaust pipe 116. It The air cleaner 114 is installed behind the engine 1 and in a large space below the fuel tank 117 and the seat 118 in order to secure the capacity. Therefore, the intake pipe 115 is connected to the rear side of the engine 1, and the exhaust pipe 116 is connected to the rear side of the engine 1. Further, a fuel tank 117 is mounted above the engine 1, and a seat 118 and a seat cowl 119 are continuously provided behind the fuel tank 117.
Here, an accelerator motor 54, which will be described later, is attached to a predetermined portion of the cylinder head 2 to the cylinder head cover 2a of the engine 1. The accelerator motor 54 is provided so as to project from the upper surface of the cylinder head cover 2a, as in the illustrated example. In that case, the accelerator motor 54 is arranged in a recess provided in the lower portion of the fuel tank 117, and the fuel tank 117 and the cylinder head cover 2 are arranged.
a is arranged so as not to interfere with each other. The accelerator motor 54 can be installed on either the intake side or the exhaust side by using a link, but when it is installed on the exhaust side, the concave portion formed in the fuel tank 117 is exposed, and the appearance deteriorates as it is. It is preferable that the accelerator motor 54 is provided on the intake side.

Further, in FIG. 2, 120 is a head lamp, 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. Further, a main stand 124 is swingably attached to a lower portion of the vehicle body frame 101 so that the rear wheel 111 can be grounded or floated from the ground. The body frame 101 includes a head pipe 102 provided at a front portion.
Is extended obliquely rearward and downward, and is curved so as to wrap around the lower side of the engine 1, and then a pivot 109a that is a pivotal support portion of the swing arm 109 is formed to connect to a tank rail and a seat rail (neither is shown). is doing.

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

FIG. 3 is a side sectional view of the main part of the device of the present invention,
4 is a sectional view taken along the line AA of FIG. 3, and FIG. 5 is a sectional view of FIG.
It is sectional drawing which follows the B line. As shown in these figures, in this embodiment, the parallel two-cylinder engine has two valves (that is, four valves) on each of the intake side (IN) and the exhaust side (EX) for each cylinder. ing. In this embodiment, the example is applied to the intake side, but it may be applied to both the intake side and the exhaust side. A cylinder head 2 is arranged above a piston 3 (see FIG. 1) that reciprocates up and down in a cylinder, and a valve operating device is housed in the cylinder head 2.

The valve train includes a cam / camshaft unit 10 arranged along the cylinder arrangement direction, a tappet unit 20 arranged coaxially with the cam / camshaft unit 10, and a valve for intake control in this example. Unit 3
0, a rocker arm unit 40 arranged between the tappet unit 20 and the valve unit 30 to move the valve back and forth, and the tappet unit 2 depending on the accelerator opening.
0, which will be described later, and an accelerator shaft unit 50 for displacing a tappet described later. The valve unit 30
Regarding the above, the exhaust side may have the same configuration.

In the cam / camshaft unit 10, the camshaft 11 is rotatably supported by the cylinder head 2 via a bearing 12 (metal bearing). A low lift cam 13 is provided for each cylinder on the camshaft 11.
And a high lift cam 14 are provided. These cams 13 and 14 are arranged adjacent to each other along the axial direction of the cam shaft 11, and are provided with a predetermined angle shift in the circumferential direction (that is, have a phase difference β shown in FIG. 3). The camshaft 11 may have a hollow structure, and a lubricating oil passage may be formed inside the hollow to lubricate the cam 13 and the like.

A sprocket 15 is connected to one end of the camshaft 11 (FIG. 5). Exhaust side camshaft 1
A sprocket 15 _Ex is also fixed to one end of 1 _Ex , and as shown in FIG. 6, a cam chain is formed between these sprockets 15 and 15 _Ex and a drive sprocket 4 fixed to one end of a crankshaft (not shown). 5 is wound and mounted. As shown in FIG. 6, a chain guide 6, a chain tensioner 7, a chain adjuster 8 and the like are provided so that the cam chain 5 travels properly.

In this example, a so-called hydraulic type cam phase varying device 70 is provided around the sprocket 15 so that it can be effectively performed without increasing the size and cost of the device. In this embodiment, a continuously variable valve timing mechanism called a "VVT mechanism" or the like can be used. In this case, since the cam shaft 11 itself does not slide to change the cam timing, the phase sensor unit described later can be effectively used.

In the tappet unit 20, a generally circular disk-shaped low lift tappet 21 is provided (corresponding to the low lift cam 13 and the high lift cam 14 for each cylinder (in the axial direction)).
(Roller tappet) and high lift tappet 22 (roller tappet) are arranged. These tappets 21, 22
Are displaced by a phase difference β as shown in FIG. 3 by a retainer described later. Tappet unit 20
The tappets 21 and 22 are pushed by the cam surfaces of the cams 13 and 14 and function as valve lifters that move the valve forward and backward via a rocker arm described later. Camshaft 11
A retainer holder 23 is fitted on the outside of the tappet 2
A retainer 24 for holding the 1, 22 is rotatably supported by a retainer holder 23. The retainer 24 has fitting portions (cylindrical inner peripheral surfaces) into which the retainer holder 23 fits inside.

The tappets 21 and 22 have supporting shafts 21a and 22a protruding from both sides, while the retainer 24 has a supporting shaft 2a.
U-shaped guide grooves 24a, 2 into which 1a, 22a are inserted
I have 4b. The guide grooves 24a and 24b are formed along the radial direction of the camshaft 11, and thereby the tappets 21 and 22 are movable in the radial direction via the support shafts 21a and 22a. Also, U of the guide grooves 24a and 24b
The V-shaped bottom portion corresponds to the camshaft radial movement amount of the tappets 21 and 22 (set by the cam heights of the low lift cam 13 and the high lift cam 14), and the guide groove 24a is shallow. The groove 24b is deeply formed.

The tappets 21 and 22 also have support shafts 21a,
22a is supported by springs 25 and 26, respectively, and elastically biased outward in the radial direction of the camshaft. As shown in FIG. 1, the springs 25 and 26 are, for example, plate-shaped springs each having a generally U-shape (see FIG. 1). The base is fixed to the retainer 24 by a screw 27, and the tappet 21, 22 support shafts 21
A and 22a are rotatably supported in a cantilever manner.

In the valve unit 30, each valve stem 31a includes two intake valves 31 guided by a valve guide 32. In addition, rocker arms 41, 4 are provided at the end of each valve stem 31a.
The valve spring 36 is mounted between the valve retainer 34 and the spring seat 35.

The rocker arm unit 40 includes rocker arms 41 and 42 slidably in contact with the tappets 21 and 22 and swingably supported for each cylinder.
In this example, the narrow tappet 21 is slidable only with the rocker arm 41, and the wide tappet 22 is slidable with both the rocker arms 41 and 42, that is, the high lift tappet 22 side (high lift). Cam 14
Side) is set so that the valve can be stopped at a predetermined phase. The rocker arms 41 and 42 are rotatably supported by the shaft 43. The shaft 43 is supported on the cylinder head 2 side and fixed by a stopper 44. An oil passage is provided in the shaft 43, and the rocker arm 4
Oil is supplied to the contact surface with 1, 42.

Here, as shown in FIG. 7, the rocker arm 41 (similarly to the rocker arm 42) has a substantially L shape, and the tappets 21 and 22 are in sliding contact with the long side of the L shape. Side sliding contact part (slipper surface) 41a
And a tappet entry / exit ramp 41b on the low lift tappet 21 side, a tappet entry / exit ramp 41c on the high lift tappet 22 side, and an L-shaped short side push for driving the valve unit 30 (the shim 33). And a portion 41d.

The shape of the sliding contact portion (slipper surface) 41a is an arc shape having a radius R which is the sum of the cam base radii of the cams 13 and 14 and the diameters of the tappets 21 and 22, and the tappets 21 and 22 are attached to the slipper surfaces. The point of contact is the force point P _{1 on} the rocker arm 41 (42). Tappet 2
By changing the phases of ₁ and 22 to change the distance L between the force point P ₁ and the fixed fulcrum P ₂ of the rocker arm 41 (42), the rocking amount of the rocker arm 41 (42), that is, the valve. The lift amount can be continuously and continuously changed. That is, when the distance L is large, the valve lift amount is small, and as the distance L becomes smaller, the valve lift amount increases. Retainer 2
The outer diameter of the rocker arms 41, 4 is 4 as shown in FIG.
In order to avoid contact interference with the slipper surface of 2, the radius R
It is set to be appropriately smaller than the above, that is, the gap X is generated with respect to the slipper surface.

In this embodiment, the exhaust side is
As shown in FIG. 1 or 3, the flat cam 13 _Ex
It has a rocker arm 41 _Ex having a (planar cam) and a contact surface that abuts on it.

In the accelerator shaft unit 50,
It includes an accelerator shaft 51 arranged in parallel with the camshaft 11, and a gear 52 for driving the tappet retainer provided on the accelerator shaft 51. A part of the retainer 24 is formed with a gear portion 24c having a length corresponding to a rotation angle required for variably controlling the valve lift amount. The accelerator shaft 51 is rotatably supported by the cylinder head 2, and a driven gear 53 (wheel) is fixed to the other end side. The driven gear 53 meshes with a drive gear 55 (worm) fixed to the output shaft of the accelerator motor 54.

The output shaft of the accelerator motor 54 rotates in response to changes in the accelerator (accelerator opening degree, acceleration / deceleration direction, etc.), and the rotation of the accelerator motor rotates the accelerator shaft 51 via the drive gear 55 and the driven gear 53. Let In the case of a motorcycle, for example, the rotational operation amount of the accelerator grip may correspond to the rotational amount of the output shaft of the accelerator motor 54. Further, when the accelerator motor 54 is driven, drive control is performed by a controller (not shown) so as to match the traveling condition (output) at that time.

Here, the other end of the camshaft 11 is shown in FIG.
Alternatively, as shown in FIG. 5, the phase sensor unit 6
0 is provided. The phase sensor unit 60 includes a pin 61 and a pin 61 that are implanted at the other end of the camshaft 11.
It includes a phase sensor 62 that detects 1 to obtain an output signal.

In the above structure, when the accelerator grip (or accelerator pedal) is operated, the accelerator motor 5
4 operates, and the accelerator shaft 51 rotates due to the rotation of the output shaft. For example, when the engine speed is low, the low lift tappet 21 slides on the slipper surface 41a of the rocker arm 41 as shown in FIG. 3 or 4.

In this case, the tappet 21 is in the state shown in FIG.
Before tapping the rocker arm 41 tappet entry / exit lamp
41c (see FIG. 7) side is in sliding contact with the sliding contact portion 41a.
By the accelerator motor 54 via the sea urchin retainer 24
Rotational drive (in this case, the retainer 24 is not
It is rotated in a clockwise direction. At this time, tappet 21 is
Immediately after leaving the lamp 41c as shown in 3,
Phase P that gives the amount_{mi n}Pass through. And the accelerator
As the opening degree increases, the accelerator motor 54
The driven gear 53 is rotated by the operation, and the accelerator
The shaft 51 rotates further and gives the maximum valve lift amount.
Phase P_max(Note that the phase P in FIG. 3 is reached._min~
Phase P_maxIs the phase difference between α). And the phase P_maxThrough
After the error, the tappet 21 moves to the ramp 41 of the rocker arm 41.
to b.

During this time, the tappet 21 is in sliding contact with only one rocker arm 41 as shown in FIG. 4, that is, when the tappet 21 is in sliding contact, the tappet 22 separated by the phase difference β acts on the rocker arm unit 40. There is nothing to do. As a result, the intake valve 31 on the high lift cam 14 side is stopped. The tappet 21 is pushed up by the low lift cam 13 every engine cycle, and lifts the valve via the rocker arm 41 each time.
In this way, the tappet 21 is rotationally driven by the accelerator motor 54 via the retainer 24, so that the sliding contact position of the rocker arm 41 with respect to the sliding contact portion 41a is continuously variable controlled, whereby the lift amount of the intake valve 31 is increased. It can be changed steplessly.

Next, when the accelerator is further opened, the retainer 24 further rotates counterclockwise in FIG. 3, the tappet 21 disengages the ramp 41b of the rocker arm 41, and the tappet 22 shifts to the phase P _{L / H.} And starts to enter the sliding contact portion 41a from the tappet entry / exit ramp 41c of the rocker arms 41, 42. In other words, tappet 2 with phase P _{L / H}
Switching between 1 and tappet 22 is performed. This tappet 2
2 is formed wide so as to be in sliding contact with both the rocker arms 41 and 42, and acts on the two rocker arms 41 and 42 so as to shift from the engine low speed to the engine middle speed at the phase P _{L / H.} Two intake valves 31
To lift. The tappet 22 enters from the ramp 41c and starts sliding contact with the sliding contact portion 41a.

Also in this case, the tappet 22 is as shown in FIG.
Immediately after leaving the ramp 41c, the phase P _min which gives the minimum valve lift amount is passed. Then, in response to the increase in the accelerator opening, the driven gear 53 is rotated by the operation of the accelerator motor 54, the accelerator shaft 51 is further rotated, and the phase P _max that gives the maximum valve lift amount is reached.

The tappet 22 is pushed up by the high lift cam 14 for each engine cycle, and the two intake valves 31 are lifted via the rocker arms 41 and 42 each time. In this way, tappet 22 and retainer 24
By being rotationally driven by the accelerator motor 54 via the slider, the sliding contact portions 41a, 4 of the rocker arms 41, 42 are
The sliding contact position with respect to 2a is continuously variable, and thus the lift amount of the intake valve 31 can be continuously variable.
On the other hand, by returning the accelerator during deceleration, the valve lift amount is reduced by the operation opposite to the above.

Here, in the above-described valve operating system or internal combustion engine of the present invention, particularly, since the fulcrum (shaft 43) of the rocker arms 41, 42 is fixed, there is no rattling, and a low rotation range to a high rotation range is achieved. The valve can be lifted by drawing an accurate lift curve. Further, since the contact between the tappets 21 and 22 and the cams 13 and 14 or the sliding contact portions 41a and 42a of the rocker arms 41 and 42 is rolling contact, wear between the contact members is extremely small, which results in durability. improves. Further, since the valve lift reaction force does not act on the mechanism side for changing the phase of the tappets 21 and 22, the phase can be changed with a small amount of force, and the accelerator motor 54 can be downsized to save power. You can

Further, two cams 13 and 14 for low lift and high lift are used, and they are arranged in the axial direction of the cam shaft 11 with a phase shift. And these cams 1
Two tappets 21,22 driven by 3,14
Is switched in a predetermined phase, that is, in two stages, so that the valve lift amount can be smoothly and continuously variably controlled in a wide range from the idling rotation range to the maximum rotation range. In addition, the low lift cam 1 configured as a separate body
3 and the cam angle 14 for high lift can be changed, the mirror cycle can be realized by narrowing or widening the cam angle on the side of the cam 13 for low lift, whereby the expansion work can be performed more than the compression work. It can be increased, and improvement in combustion efficiency can be expected.

Further, rocker arms 41 and 42 are provided for each valve, and the tappet 21 is one rocker arm 4
1 and tappet 22 are both rocker arms 4
By making the sliding contact with 1 and 42 possible, one intake valve 31 can be stopped at the time of low lift. As a result, the intake air inflow speed can be increased in the low-medium speed (low-medium output) range to enhance the swirl or tumble flow to achieve a lean burn, while avoiding the reaction force from the valve spring on the rest side to reduce mechanical loss. Improve output.

Further, the rocker arm 41 on the lift side is always provided.
A tappet entry / exit ramp 41 that gradually moves away from the cam center from the sliding contact portion 41a on the fulcrum side (on the side of the low lift cam 13)
b is provided, and the tappet entry / exit ramp 41c on the high lift cam 14 side is provided on the opposite side of the fulcrum. Then, the tappets 21 and 22 are urged by the springs 25 and 26 to positions where they do not hit the cams 13 and 14, respectively. As a result, one of the tappets 21 and 22 on the side where the valve is not lifted does not make a sliding contact operation, so that operating noise and wear do not occur. Further, when the tappets 21 and 22 are switched, the tappet contact surface and the cam surface gradually come into contact with each other, so that not only the contact surface is not damaged, but also the generation of sound can be suppressed.

Further, the cam phase changing device 70 adjusts the lift timing change by changing the phase of the tappets 21 and 22. In the present invention, since the phases of the cams 13 and 14 and the tappets 21 and 22 are changed to change the valve lift amount, the phase of the tappets 21 and 22 is changed to change the valve lift amount without changing the lift timing. It is necessary to change the phases of the camshaft 11 and the drive sprocket 4 in synchronization with each other. Cam phase changing device 70
Therefore, the lift timing can be freely changed and adjusted by shifting only the amount of tuning.

[0055] Further, the sliding contact portion 41a of the rocker arm 41, the arrangement position of 42a, by placing at approximately a right angle or less angle with respect to the point 41d around its fulcrum P _2, locker The weight of the arms 41 and 42 can be reduced, and high rotation can be achieved. Further, by setting the position of the cam shaft 11 to the upper side with respect to the cylinder head surface, it becomes easy to make the intake port a vertically long shape,
As a result, the tumble flow can be strengthened and combustion efficiency can be increased, so that high output can be achieved.

Further, the outer diameter of the retainer 24 is substantially equal to the sliding contact portion 4
The radius of curvature of 1a and 42a is made the same (the gap X is almost 0) to prevent so-called dripping operation in which the valve on the rest side flaps. By preventing the idle valve operation of the rest side valve without another special component, the cost and the weight can be reduced.

Further, the variable angle of the cam phase varying device 70 is set to 2α or more, and the phase difference between the low lift cam 13 and the high lift cam 14 is set to β> α.
22 can be prevented from slidingly contacting the cams 13 and 14 at the same time, and the angle can be continuously changed by the cam phase changing device 70, so that the timing deviation can be prevented.

Next, a second embodiment according to the present invention will be described. The same or corresponding members as those in the first embodiment described above are designated by the same reference numerals and will be described with reference to the drawings. 8 is a plan sectional view (corresponding to FIG. 4) of the main part of the device of the present invention, and FIG. 9 is a sectional view (corresponding to FIG. 5) of the main part. In this embodiment, the example is applied to the intake side, but in addition to this, the example may be applied to the exhaust side. A cylinder head 2 is arranged above the piston 1 that reciprocates up and down in the cylinder, and the valve operating device is housed in the cylinder head 2.

The valve gear according to the second embodiment includes a cam / camshaft unit 10 arranged along the cylinder arrangement direction, and a tappet unit 20 coaxially arranged around the cam / camshaft unit 10. In this example, a valve unit 30 that controls intake, a rocker arm unit 40 that is arranged between the tappet unit 20 and the valve unit 30 to move the valve forward and backward, and a tappet, which will be described later, of the tappet unit 20 according to the accelerator opening. The accelerator shaft unit 50 for displacing is included. The valve unit 30 may have the same configuration on the exhaust side.

In this embodiment, the cam phase varying device 7
Since the basic configuration other than 0 is substantially the same as that of the first embodiment, the description thereof will be omitted here. The cam phase varying device 70 of the second embodiment mechanically variably controls the valve timing and shares its operation with the tappet retainer drive device (accelerator shaft unit 50).

In the cam phase varying device 70, the cam shaft 11 has an extending portion 11a, one end of which extends through the sprocket 15. The extended portion 11a at this end
A cam phase varying device 70 is formed around the. Also,
As shown in FIG. 8, one end of the accelerator shaft 51 has an extending portion 51a extending substantially parallel to the extending portion 11a of the camshaft 11. The extended portion 51a of the accelerator shaft 51 has a drive gear 71 for tuning the tappet.
Sticks. A driven gear 72a that meshes with the drive gear 71 is coaxial with the extended portion 11a side of the camshaft 11.
A rotating body 72 having is arranged. This rotating body 72
It is rotatably supported by a boss 73 fixed to the cylinder head 2.

The rotating body 72 is an internal tooth type torsion spline 72.
an outer slider 74 having an externally toothed torsion spline 74a which has a b and which meshes with the torsion spline 72b.
Are arranged inside the rotating body 72. Outer slider 74
Holds an inner slider 76 rotatably inside thereof via a bearing 75. A ball spline 76a is formed inside the inner slider 76, and a ball 77 is inserted between the inner slider 76 and the ball spline 11b formed on the extending portion 11a of the camshaft 11 (see FIG. 1).
0), and is integrally formed with the camshaft 11 so as to rotate.

Further, the inner slider 76 is formed with an external tooth type torsion spline 76b on the outer side thereof, and this torsion spline 76b meshes with an internal tooth type torsion spline 78a formed on the slider holder 78. The slider holder 78 is fixed to the sprocket 15 with screws 79. In addition, a guide protrusion 74b that is formed to protrude toward the cylinder head 2 side is provided on a part of the outer slider 74. As shown in FIG. 10, the guide protrusion 74b engages with the guide groove 2b formed in the cylinder head 2, so that the outer slider 74 is allowed to move to the camshaft 11.
It is slide-guided along the axial direction.

In the second embodiment, the basic operation of the device is substantially the same as that of the first embodiment described above. That is, the two cams 13 and 14 for low lift and high lift are used, and they are arranged in the axial direction of the camshaft 11 and with a phase shift. In this case, the cams 13, 1
The two tappets 21 and 22 driven by 4 are rotationally driven by the accelerator motor 54 via the retainer 24. As a result, the sliding contact position of the rocker arms 41, 42 with respect to the sliding contact portions 41a, 42a can be continuously variable controlled, and the lift amount of the intake valve 31 can be continuously variable.

Particularly in the second embodiment, the intake valve 31
Of the accelerator motor 54 when continuously controlling the lift amount of the vehicle
The rotation of the accelerator shaft 51 causes the rotation of the accelerator shaft 51 to rotate the rotating body 72 via the drive gear 71 and the driven gear 72a. The rotation of the rotating body 72 is converted into the sliding operation of the outer slider 74. For example, when the accelerator is opened, the outer slider 74 moves from the state shown in FIG. 9 to the inner slider 76.
And slide to the right in the figure. As a result, the phase of the sprocket 15 with respect to the camshaft 11 changes in accordance with the rotation amount of the accelerator shaft 51 via the slider holder 78.

In this way, the cam phase varying device 70 is mechanically connected to the accelerator shaft unit 50, and the drive source of the accelerator shaft unit 50 changes the phases of the cam shaft 11 and the sprocket 15 by an amount corresponding to the accelerator change. That is, the valve timing deviation is corrected simultaneously with the switching of the valve lift amount.

The tappet 21 for the camshaft 11,
Since the phase change of 22 and the phase change of the sprocket 15 are mechanically synchronized by the same drive source, there is no risk of malfunction and there is no danger of valve damage or the like. Also,
When a hydraulic continuously variable valve timing mechanism is used, a hydraulic control device and accuracy are required. However, the cam phase varying device 70 of the present embodiment has a simple structure and can be an inexpensive engine.

Further, a twist spline (or an oblique cam may be used) or the like is used in the cam phase varying device 70, and the rotation angle is changed to correct the shift of the valve timing in response to the change of the valve lift amount. In this case, the valve timing is adjusted so that the overlap amount of the lift curve is small when the valve lift amount is small, and the overlap amount of the lift curve is large when the valve lift amount is large. Then, the timing is advanced as the valve lift amount increases. In this way, by varying the valve overlap amount in proportion to the valve lift amount (that is, engine output), it is possible to prevent blow-through in the low-medium speed range and realize the output increase in the high-speed range.

Next, a third embodiment according to the present invention will be described. The same or corresponding members as those in the first embodiment described above are designated by the same reference numerals and will be described with reference to the drawings. FIG. 11 is a side sectional view of an essential part of the device of the present invention, and FIG. 12 is FIG.
1 is a sectional view taken along line DD of FIG. 1, and FIG. 13 is a sectional view taken along line EE of FIG. 11. As shown in these figures,
This embodiment is a parallel two-cylinder engine, and each cylinder has two valves (that is, four valves) on the intake side (IN) and the exhaust side (EX). In addition,
In this embodiment, the example is applied to the intake side, but it may be applied to both the intake side and the exhaust side. A cylinder head 2 is arranged above a piston 3 (see FIG. 1) that reciprocates up and down in a cylinder, and a valve operating device is housed in the cylinder head 2.

The valve operating system according to the third embodiment comprises a cam / camshaft unit 10 arranged along the arrangement direction of cylinders, and a tappet unit 20 coaxially arranged around the cam / camshaft unit 10. In this example, a valve unit 30 for intake control, a rocker arm (hereinafter referred to as “swing arm”) unit 80 arranged between the tappet unit 20 and the valve unit 30 to move the valve forward and backward, and an accelerator opening degree. And an accelerator shaft unit 50 for displacing a tappet of the tappet unit 20, which will be described later. The valve unit 30 may have the same configuration on the exhaust side. Further, among these, those basically the same as those in the first embodiment will be omitted or simplified as appropriate.

In the cam / camshaft unit 10, the camshaft 11 is rotatably supported by the cylinder head 2 via the bearing 12. Camshaft 1
As shown in FIG. 11, 1 is arranged substantially on the extension line of the valve stem 31a of the valve unit 30. The camshaft 11 is provided with a low lift cam 13 and a high lift cam 14 for each cylinder. In this case, of the two intake valves 31 in each cylinder, both the low lift cam 13 and the high lift cam 14 are provided on the normally lift side, and only the high lift cam 14 is provided on the idle side. To be done. These cams 13 and 14 are the camshaft 1
The cams are arranged adjacent to each other along the axial direction of 1 and are displaced by a predetermined angle in the circumferential direction (that is, corresponding to the phase difference β between the low lift tappet 21 and the high lift tappet 22 shown in FIG. 13 and 14 are also offset by a predetermined angle). The camshaft 11 may have a hollow structure, and a lubricating oil passage may be formed inside the hollow to lubricate the cam 13 and the like.

A sprocket 15 is connected to one end of the camshaft 11 (FIG. 12), and one end of the sprocket 15 is connected to the sprocket 15.
Has an extending portion 11a that extends through. The cam phase varying device 70 already described in the second embodiment is configured around the extending portion 11a at this one end.

In the tappet unit 20, the low-lift tappet 21 having a substantially disc shape is provided for each cylinder (corresponding to the low-lift cam 13 and the high-lift cam 14 (in the axial direction)).
(Roller tappet; Fig. 12) and high lift tappet 22
(Roller tappet; FIG. 13) is arranged. It should be noted that both the low lift tappet 21 and the high lift tappet 22 are always provided on the lift side, and only the high lift tappet 22 is provided on the rest side. These tappets 21 and 22 are displaced by a phase difference β by a retainer described later, as shown in FIG. The tappet unit 20 (tappets 21, 22) has cams 13, 14
It functions as a valve lifter that is pushed by the cam surface and moves the valve back and forth via a swing arm described later.

A retainer holder 23 is arranged around the camshaft 11, and a retainer 24 for holding the tappets 21 and 22 is rotatably supported by the retainer holder 23. The retainer 24 is at both ends
Fitting part (cylindrical inner peripheral surface) into which retainer holder 23 is fitted
have. In this example, three retainer holders 23 _L , 23 _M , and 23 _R are provided along the axial direction of the cam shaft 11.

The tappets 21 and 22 have supporting shafts 21a and 22a protruding from both sides, while the retainer 24 has the supporting shaft 2a.
U-shaped guide grooves 24a, 2 into which 1a, 22a are inserted
I have 4b. The guide grooves 24a and 24b are formed along the radial direction of the camshaft 11, and thereby the tappets 21 and 22 are movable in the camshaft radial direction via the support shafts 21a and 22a.

The tappets 21 and 22 are held by the holding forks 28 and 29 at positions radially separated from the cam shaft 11 so that they do not come into sliding contact with the cams 13 and 14 when there is no lift. . As shown in FIG. 14, the holding fork 28 has an arc shape that guides the support shaft 21a of the low lift tappet 21 in the phase without lift (at least the radius that prevents the tappet 21 from sliding contact with the cam 13). The inner guide portion 28a (which is set) and the outer guide portion 28b which regulates the outer peripheral portion of the tappet 21 are provided. The holding fork 29, like the holding fork 28, acts on the high lift tappet 22 that is in the phase without lift.
9a and the outer guide part 29b.

Between the holding fork 28 and the holding fork 29, when the tappet 21 or 22 is separated from the holding forks 28, 29, the guide grooves 24a, 24 are formed.
An opening 201 is provided to allow movement along b. The opening 201 corresponds to the range of the phase P _min that gives the minimum valve lift amount and the phase P _max that gives the maximum valve lift amount (the phase difference α between the phases P _min and P _max ) (see FIG. 15). ). The phase P _min and the phase P _max are center-distributed with the central phase P _C passing through the valve stem 31a interposed therebetween. Further, the inner guide portions 28a of the holding forks 28, 29,
Inclined surfaces 28c and 29c are formed at the ends of 29a. By providing these inclined surfaces 28c and 29c, the support shafts 21a and 22a of the tappets 21 and 22 can smoothly enter the inner guide portions 28a and 29a, respectively.

Since the structure of the valve unit 30 is substantially the same as that of the first embodiment, its explanation is omitted here.

The swing arm unit 80 includes swing arms 81, 82 slidably contactable with the tappets 21, 22 and swingably supported for each cylinder.
In this example, of the two valves, both tappets 21 and 22 can be in sliding contact with the wide swing arm 81 at all times on the lift side, and the tappet 22 can be in sliding contact with the swing arm 82 at the rest side. That is, the high lift tappet 22 side (high lift cam 14 side) is set so that the valve can be stopped at a predetermined phase. The swing arms 81 and 82 are rotatably supported by a shaft 83. The shaft 83, via the retainer holder 23,
It is supported on the side of the cylinder head 2 (see FIG. 13). An oil passage is provided in the shaft 83 to supply oil to the contact surfaces with the swing arms 81 and 82.

Here, as shown in FIG. 15, the swing arm 81 (the same applies to the swing arm 82).
Is a sliding contact portion (slipper surface) 81a in which the tappets 21 and 22 are in sliding contact with each other, a tappet entry / exit lamp 81b on the low lift tappet 21 side, and a high lift tappet 2
It has a tappet entry / exit lamp 81c on the second side and a pressing portion 81d for pressing and driving the valve unit 30 (the shim 33).

The shape of the sliding contact portion (slipper surface) 81a is an arc having a radius that is the sum of the cam base radius of the cams 13 and 14 and the diameter of the tappets 21 and 22, and the tappets 21 and 22 contact the slipper surfaces. The point to do becomes a force point with respect to the swing arm 81 (82). Tappets 21,22
By changing the phase of the swing arm 81 (82) by varying the distance between the force point and the fixed fulcrum (shaft 83) of the swing arm 81 (82).
It is possible to continuously and continuously change the swing amount of the valve, that is, the valve lift amount. That is, when the distance is large, the valve lift amount is small, and the valve lift amount increases as the distance decreases.

In this embodiment, the exhaust side is
As shown in FIG. 11 or FIG. 16, it has a tappet 21 _{Ex that} is in sliding contact with the flat cam 13 _Ex and a swing arm 81 _Ex that supports the tappet 21 _Ex .

In the accelerator shaft unit 50,
It includes an accelerator shaft 51 arranged in parallel with the camshaft 11, and a gear 52 for driving the tappet retainer provided on the accelerator shaft 51. A part of the retainer 24 is formed with a gear portion 24c having a length corresponding to a rotation angle required for variably controlling the valve lift amount. The accelerator shaft 51 is rotatably supported by the cylinder head 2, and a driven gear 53 (wheel) is fixed to the other end side. The driven gear 53 meshes with a drive gear 55 (worm) fixed to the output shaft of the accelerator motor 54.

The output shaft of the accelerator motor 54 rotates in response to an accelerator change (accelerator opening degree, acceleration / deceleration direction, etc.), and its rotation rotates the accelerator shaft 51 via a drive gear 55 and a driven gear 53. Let In the case of a motorcycle, for example, the rotational operation amount of the accelerator grip may correspond to the rotational amount of the output shaft of the accelerator motor 54. Further, when the accelerator motor 54 is driven, drive control is performed by a controller (not shown) so as to match the traveling condition (output) at that time.

The other end of the camshaft 11 is shown in FIG.
2, the phase sensor unit 60 is provided. The phase sensor unit 60 includes the camshaft 1
1 includes a pin 61 implanted at the other end and a phase sensor 62 that detects the pin 61 and obtains an output signal.

In this embodiment, the cam phase varying device 7
0 is substantially the same as in the second embodiment. As described above, the cam phase varying device 70 mechanically variably controls the valve timing and shares its operation with the tappet retainer driving device (accelerator shaft unit 50).

In the above structure, when the accelerator grip (or accelerator pedal) is operated, the accelerator motor 5
4 operates, and the accelerator shaft 51 rotates due to the rotation of the output shaft. For example, when the engine speed is low,
Alternatively, as shown in FIG. 12, the low lift tappet 2
1 is always in sliding contact with the lift-side swing arm 81.

In this case, in the state shown in FIG. 11, the tappet 21 has the sliding contact portion 81a immediately after it is detached from the lamp 81c,
That is, it is located at the phase P _min that gives the minimum valve lift amount. Then, as the accelerator opening increases, the driven gear 53 is activated by the operation of the accelerator motor 54.
Rotates, the accelerator shaft 51 further rotates, and the tappet 21 reaches the phase P _max that gives the maximum valve lift amount. Then, after passing through the phase P _max , the tappet 21
Reaches the ramp 81b of the swing arm 81.

During this time, the tappet 21 is always in sliding contact with the swing arm 81 on the lift side as shown in FIG.
That is, the tappets 22 separated by the phase difference β during the sliding contact of the tappet 21 do not always act on the swing arm unit 80 on both the lift side and the rest side. The tappet 21 is pushed up by the low lift cam 13 every engine cycle, and lifts the valve via the swing arm 81 each time. In this way, the tappet 21 is rotationally driven by the accelerator motor 54 via the retainer 24, whereby the sliding contact portion 81 of the swing arm 81 is moved.
By continuously controlling the sliding contact position with respect to a, the lift amount of the intake valve 31 can be continuously changed.

Next, when the accelerator is further opened, the retainer 24 further rotates counterclockwise in FIG. 11, the tappet 21 disengages the ramp 81b of the swing arm 81, and the tappet 22 shifts to the phase P _{L / H.} From the tappet entry / exit lamp 81c of the swing arm 81 to the sliding contact portion 81
Start entering a. In this case, the tappet 22 on the rest side similarly starts sliding contact with the rocker arm 82. Phase P
_{In order} to shift from low engine speed to medium engine speed with _{L / H} ,
The normally lift side and rest side tappets 22 act on the two swing arms 81 and 82, and thus lift the two intake valves 31.

Also in this case, each tappet 22 is as shown in FIG.
Immediately after leaving the lamp 81c, the minimum valve lift amount is given.
Phase P_minPass through. And the accelerator opening is large
As the accelerator motor 54 operates,
The driven gear 53 rotates and the accelerator shaft 51
Is rotated further, and the phase P that gives the maximum valve lift amount
_maxTo reach.

The tappet 22 is pushed up by the high lift cam 14 every engine cycle, and the two intake valves 31 are lifted via the swing arms 81 and 82 each time. In this way, tappet 22 and retainer 24
By being rotationally driven by the accelerator motor 54 via the slider, the sliding contact portions 81a, 8a of the swing arms 81, 82
The sliding contact position with respect to 2a is continuously variable, and thus the lift amount of the intake valve 31 can be continuously variable.
On the other hand, by returning the accelerator during deceleration, the valve lift amount is reduced by the operation opposite to the above.

Particularly in the third embodiment, the camshaft 1
1 is arranged on an almost extended line of the valve stem 31a of the valve unit 30, and the slipper surfaces of the tappets 21, 22 and the swing arms 81, 82 are arranged substantially on the line. First of all, since it is a swing arm type, the weight of reciprocating parts is reduced to enable high acceleration and high rotation of the valve lift operation, thereby realizing a high rotation and high output engine suitable for two-wheeled vehicles. Further, by arranging the respective members on the line as described above, it is possible to make the cylinder head 2 and its surroundings compact, and it is easy to make the intake port a vertically long shape, which makes it possible to strengthen the tumble flow and to combust. Since the efficiency can be increased, higher output can be achieved.

Further, the high lift cams 14 are set on both the normal lift side and the rest side, and the wide swing arm 81 is used on the normal lift side. For the swing arm 81 having this weight, the high lift cam 14 is a cam that gives an acceleration that matches the weight of the reciprocating components, and on the rest side, the swing acceleration is increased by the amount that the swing arm 82 becomes lighter. be able to. As a result, high output can be achieved.

Further, the phase strokes of the tappets 21 and 22 (phase P _min to phase P _max ; phase difference α) are set by distribution across the central phase P _C passing through the valve stem 31a. As a result, it is possible to reduce the deviation between the force points and the action points with respect to the swing arms 81 and 82, so that it is possible to reduce the allowable bending stress of the swing arms 81 and 82 and reduce the weight, resulting in higher rotation. is there. In this case, since it is possible to set the phase of the low lift side and the phase of the high lift side by distributing to the arm ratio 1, it is easy to increase the ratio of the high lift to the low lift. By using two types of cams, the low lift cam 13 and the high lift cam 14, the valve lift amount can be set steplessly to about 1 mm (when idling) to 8 mm (maximum lift amount).

In the third embodiment, in order to prevent the cam ridges from hitting the tappets 21 and 22 in the phase without lift, for example, arc magnets are provided near the tappet entry / exit lamps 81b and 81c. Can be placed. With this magnet, tappets 21 and 22 without lift
Is held by suction at a position (radial direction) where it does not hit the cam lobe. By using such a magnet, it is possible to collect iron powder that may be generated at a sliding contact portion between parts and prevent the wear of the tappet from occurring. In that case, the iron powder may be collected at a portion other than the tappet rolling portion by making the magnetic force of the other portion or portion larger than that of the tappet rolling portion where the magnet is arranged.

When switching the two tappets 21 and 22 in a predetermined phase, it is possible to smoothly connect the holding fork 28 or the holding fork 29 and the swing arm 81 with the tappet insertion / removal lamp 81b or 81c. . As a result, the switching operation of the tappets 21 and 22 is smoothly performed, and uniform engine rotation is guaranteed.

Further, it is possible to provide a rolling bearing between the tappet retainer sliding surface and the tappet retainer sliding surface where friction is generated by the component force vector of the cam lift. As a result, a perfect sliding contact is made between the cam and tappet, and normal surface treatment can be used. Also, there will be rolling contact between the tappet and tappet retainer,
The wear resistance can be greatly improved. Then, it is possible to ensure a smooth tappet operation for a long period of time without increasing the gap between the tappet and the tappet retainer. Alternatively, the tappet shape may be an I (eye) shape, a space for holding the needle roller may be set by the tappet retainer and the tappet, and the needle roller may be received by "total rolling". As a result, the retainer for holding the needle roller becomes unnecessary, so that the weight and cost can be reduced.

Next, a fourth embodiment according to the present invention will be described. The same or corresponding members as those in the first embodiment described above are designated by the same reference numerals and will be described with reference to the drawings. FIG. 17 is a side sectional view of an essential part of the device of the present invention, and FIG. 18 is FIG.
7 is a sectional view taken along line GG of FIG. 7, and FIG. 19 is a sectional view taken along line HH of FIG. As shown in these figures,
This embodiment is a parallel two-cylinder engine, and each cylinder has two valves (that is, four valves) on the intake side (IN) and the exhaust side (EX). In addition,
In this embodiment, the example is applied to the intake side, but it may be applied to both the intake side and the exhaust side. A cylinder head 2 is arranged above a piston 3 (see FIG. 1) that reciprocates up and down in a cylinder, and a valve operating device is housed in the cylinder head 2.

The valve gear according to the fourth embodiment includes a cam / camshaft unit 10 arranged along the cylinder arrangement direction and a tappet unit 20 coaxially arranged around the cam / camshaft unit 10. In this example, a valve unit 30 that controls intake, a swing arm unit 80 that is arranged between the tappet unit 20 and the valve unit 30 to move the valve forward and backward, and a tappet, which will be described later, of the tappet unit 20 according to the accelerator opening. The accelerator shaft unit 50 for displacing is included. The valve unit 30 may have the same configuration on the exhaust side. Further, among these, those basically the same as those in the first embodiment will be omitted or simplified as appropriate.

The basic structure of this embodiment is substantially the same as that of the third embodiment. By the way, when the tappet stroke is set in the radial direction of the camshaft as in the third embodiment, the contact point between the slipper surface of the swing arm and the tappet shifts toward the swing arm shaft side as the lift height increases on the maximum lift phase side. For,
The arm ratio is increased and the lift amount is increased. Therefore, if the lift curve has no problem with the acceleration at the maximum lift, the lift characteristics at the minimum lift will be gradual, and the curve will be difficult to produce a low output. Therefore, in the fourth embodiment, the tappet stroke direction is set to be inclined with respect to the radial direction of the camshaft to obtain a more excellent lift curve.

Since the structure of the cam / camshaft unit 10 is substantially the same as that of the third embodiment,
The description is omitted here. In the fourth embodiment, in particular, the camshaft 11 is arranged in a so-called "V bank" defined in a V shape by the valve stem 31a of the intake / exhaust side valve unit 30, as shown in FIG. It

In the tappet unit 20, both the low lift tappet 21 and the high lift tappet 22 are always provided on the lift side, and only the high lift tappet 22 is provided on the rest side. These tappets 2
The retainers 1 and 22 are displaced by a phase difference β as shown in FIG. 20 by a retainer described later. The tappet unit 20 (tappets 21, 22) functions as a valve lifter that is pushed by the cam surfaces of the cams 13, 14 to move the valve forward and backward via a swing arm described later.

A retainer holder 23 is arranged around the camshaft 11, and a retainer 24 for holding the tappets 21 and 22 is rotatably supported by the retainer holder 23. The retainer 24 is the tappet 21,
Guide groove 24 into which the support shafts 21a, 22a of 22 are inserted
I have a and 24b. In this embodiment, the guide groove 2
The arrangement relationship of 4a and 24b is opposite to that of the above-described third embodiment, that is, the guide groove 24b is arranged outside (rear side) of the cylinder head 2.

In the fourth embodiment, the guide groove 2 is particularly used.
4a and 24b are formed to be inclined with respect to the radial direction of the cam shaft 11 (FIG. 17, angle δ). That is, these guide grooves 24a, 24b are separated from the fulcrum (shaft 83) of the swing arms 81, 82 as the tappets 21, 22 lift (swing arm 8).
The direction of approaching the front end side of 1, 82) is set.

The tappets 21 and 22 are held by the holding forks 28 and 29 at the predetermined positions in the stroke direction so as not to come into sliding contact with the cams 13 and 14 when there is no lift. In this embodiment, the arrangement relationship between the holding forks 28 and 29 is opposite to that in the case of the above-described third embodiment, that is, the holding fork 29 is arranged outside (rear side) of the cylinder head 2.

Since the structure of the valve unit 30 is substantially the same as that of the first embodiment, the description thereof will be omitted here.

The swing arm unit 80 includes swing arms 81 and 82 slidably contactable with the tappets 21 and 22 and swingably supported for each cylinder.
The swing arms 81 and 82 are rotatably supported by a shaft 83. The shaft 83 is supported on the side of the cylinder head 2 via the retainer holder 23. In the fourth embodiment, in particular, the shaft 83 (swing fulcrum of the swing arms 81 and 82) is arranged in the “V bank” of the valve stem 31a described above, as shown in FIG.

Swing arm 81 (swing arm 82
Is the same as above), as already shown in FIG.
A sliding contact portion (slipper surface) 81a adapted to make sliding contact with the tappets 21 and 22, a tappet entry / exit lamp 81b on the low lift tappet 21 side, and a tappet entry / exit lamp 81c on the high lift tappet 22 side, Valve unit 30
And a pressing portion 81d for pressing and driving the (tuppet shim 33).

In the accelerator shaft unit 50,
It includes an accelerator shaft 51 arranged in parallel with the camshaft 11, and a gear 52 for driving the tappet retainer provided on the accelerator shaft 51. A part of the retainer 24 is formed with a gear portion 24c having a length corresponding to a rotation angle required for variably controlling the valve lift amount. The accelerator shaft 51 is rotatably supported by the cylinder head 2, and has a fan-shaped driven gear 53 on the other end side.
Is stuck. The driven gear 53 is the accelerator motor 5
4 meshes with the drive gear 55 (worm) fixed to the output shaft 4.

In this embodiment, the cam phase varying device 7
0 is substantially the same as in the third embodiment. As described above, the cam phase varying device 70 mechanically variably controls the valve timing and shares its operation with the tappet retainer driving device (accelerator shaft unit 50).

In the fourth embodiment, the basic operation of the apparatus is substantially the same as that of the third embodiment described above. That is, the two cams 13 and 14 for low lift and high lift are used, and they are arranged in the axial direction of the camshaft 11 and with a phase shift. In this case, the cams 13, 1
The two tappets 21 and 22 driven by 4 are rotationally driven by the accelerator motor 54 via the retainer 24. As a result, the sliding contact position of the swing arms 81, 82 with respect to the sliding contact portions 81a, 82a can be continuously variable controlled, and the lift amount of the intake valve 31 can be continuously variable.

Especially in the fourth embodiment, the tappet 21,
The stroke direction of 22 is set at an angle δ with respect to the radial direction of the camshaft 11. As a result, when the sliding contact position between the slipper surfaces of the swing arms 81 and 82 and the tappets 21 and 22 approaches the fulcrum of the swing arms 81 and 82, the tappets 21 and 22 lift from the fulcrum of the swing arms 81 and 82 as they lift. Separate. The operation of the tappets 21 and 22 prevents the lever ratio (arm ratio) from increasing, and the cams 13 and 14 prevent the tappets 21 and 22 from moving.
It is possible to reduce the amount of force required to push down. Further, the relationship between the phase change of the tappets 21 and 22 and the lift amount can be made to be close to linear, and the lift curves from the minimum lift to the maximum lift can be made similar, thereby improving the output on the low lift side. You can

Further, the cam shaft 11 and the shaft 8
3 and the like are arranged in the "V bank" of the valve stem 31a. As a result, the pitch between the camshafts can be reduced between the intake and exhaust sides, and the front-rear direction of the cylinder head 2 can be made particularly compact. Further, the angle formed between the intake port and the axial direction of the cylinder 3 can be made small (the angle θ in FIG. 17 can be made large), the tumble flow can be strengthened, and the combustion efficiency can be improved, so that high output can be achieved. become. Further, as shown in FIG. 17, by tilting the spark plug toward the exhaust side, the V bank angle can be made smaller, which is advantageous in terms of compactness and the like.

Next, a fifth embodiment according to the present invention will be described. The same or corresponding members as those in the first embodiment described above are designated by the same reference numerals and will be described with reference to the drawings. 22 is a side sectional view of the main part of the device of the present invention, and FIG. 23 is FIG.
2 is a sectional view taken along line I-I, and FIG. 24 is a sectional view taken along line JJ in FIG. As shown in these figures,
This embodiment is a parallel two-cylinder engine, and each cylinder has two valves (that is, four valves) on the intake side (IN) and the exhaust side (EX). In addition,
In this embodiment, the example is applied to the intake side, but it may be applied to both the intake side and the exhaust side. A cylinder head 2 is arranged above a piston 3 (see FIG. 1) that reciprocates up and down in a cylinder, and a valve operating device is housed in the cylinder head 2.

The valve operating system according to the fifth embodiment comprises a cam / camshaft unit 10 arranged along the arrangement direction of cylinders, and a tappet unit 20 coaxially arranged around the cam / camshaft unit 10. In this example, a valve unit 30 that controls intake, a swing arm unit 80 that is arranged between the tappet unit 20 and the valve unit 30 to move the valve forward and backward, and a tappet, which will be described later, of the tappet unit 20 according to the accelerator opening. The accelerator shaft unit 50 for displacing is included. The valve unit 30 may have the same configuration on the exhaust side.

Further, of these, those basically the same as those in the first embodiment will be omitted or simplified as appropriate. Furthermore, the basic configuration of this embodiment is substantially the same as that of the above-described fourth embodiment.

The structure of the cam / camshaft unit 10 is substantially the same as that of the fourth embodiment.
As shown in FIG. 22, the cam shaft 11 is arranged in a so-called “V bank” defined by a valve stem 31 a of the intake / exhaust side valve unit 30 in a V shape.

In the cam / camshaft unit 10, the camshaft 11 is rotatably supported by the cylinder head 2 via the bearing 12. Camshaft 1
1, a low lift cam 13 and a high lift cam 14 are provided for each valve for each cylinder. These cams 1
3, 14 are arranged adjacent to each other along the axial direction of the cam shaft 11 and are provided with a predetermined angle shift in the circumferential direction.

In the tappet unit 20, the low-lift tappet 21 (roller tappet) having a substantially disc shape is provided (corresponding to the low-lift cam 13 and the high-lift cam 14 (axial direction) for each valve for each cylinder. And a high lift tappet 22 (roller tappet). These tappets 21 and 22 are displaced by a phase difference β by a retainer described later, as shown in FIG. The tappet unit 20 (tappets 21, 22) is pushed by the cam surface of the cam 13 and functions as a valve lifter that advances and retracts the valve via a rocker arm described later.

Since the structure of the valve unit 30 is substantially the same as that of the first embodiment, the description thereof will be omitted here.

The swing arm unit 80 includes swing arms 81 and 82 slidably contactable with the tappets 21 and 22 and swingably supported for each cylinder.
In this example, both tappets 21 and 22 are configured to be capable of sliding contact with the swing arm 81 or the swing arm 82, respectively.

In this embodiment, the exhaust side is
As shown in FIG. 11 or FIG. 16, it has a tappet 21 _{Ex that} is in sliding contact with the flat cam 13 _Ex and a swing arm 81 _Ex that supports the tappet 21 _Ex .

In the accelerator shaft unit 50,
An accelerator shaft 51 arranged in parallel with the camshaft 11 and a gear 52 for driving the tappet retainer provided on the accelerator shaft 51 (in this example, 2 for each cylinder).
One) is included. A part of the retainer 24 is formed with a gear portion 24c having a length corresponding to a rotation angle required for variably controlling the valve lift amount. The accelerator shaft 51 is rotatably supported by the cylinder head 2, and a fan-shaped driven gear 53 is fixed to the other end side.
The driven gear 53 meshes with a drive gear 55 (worm) fixed to the output shaft of the accelerator motor 54.

The output shaft of the accelerator motor 54 rotates in response to changes in the accelerator (accelerator opening, acceleration / deceleration direction, etc.), and its rotation rotates the accelerator shaft 51 via the drive gear 55 and the driven gear 53. Let In the case of a motorcycle, for example, the rotational operation amount of the accelerator grip may correspond to the rotational amount of the output shaft of the accelerator motor 54. Further, when the accelerator motor 54 is driven, drive control is performed by a controller (not shown) so as to match the traveling condition (output) at that time.

Here, the other end of the camshaft 11 is shown in FIG.
As shown in FIG. 3, the phase sensor unit 60 is provided. The phase sensor unit 60 includes the camshaft 1
1 includes a pin 61 implanted at the other end and a phase sensor 62 that detects the pin 61 and obtains an output signal.

In the cam phase varying device 70, a timing tuning cam 701 is fitted in a key 702 on the extending portion 51a of the accelerator shaft 51. A fork 703 is externally fitted to the cam 701, and a pin 704 fixed to the fork 703 is engaged with a guide groove 701a formed in the cam 701 (see FIG. 25). The pin 704 is fixed by the split pin 705. The fork 703 is connected to the outer slider 74.

By the way, for example, when one valve is stopped as in the fourth embodiment, the swirl or tumble flow becomes strong, and the fuel consumption due to lean burn can be greatly improved. In this case, as shown in FIG. 26, the valve opening area is doubled when switching to both valves, and the output difference before and after switching becomes large. For this reason, the Y value shown in the figure cannot be made too large. Therefore, in the fifth embodiment, smooth switching can be performed when the valve is stopped and when it is not used.

When the low lift cam 13 is used, one valve is stopped and the maximum lift amount on the low lift side is set as high as possible with respect to the minimum lift amount on the high lift side (X in FIG. 26).
Value), so that there is no difference in valve opening area when switching. In other words, the Y value is increased and the opening area of one valve is
Close to the opening area of both valves at the time of minimum lift on the high lift side.

As a result, the output difference at the time of switching becomes small,
You can switch smoothly. Further, even if the working angle of the low lift cam 13 is reduced and the Y value is increased correspondingly even in the mirror cycle, smooth switching can be performed.

Further, as shown in the drawing, the low lift cam 13
And the high lift cam 14 are configured so that the maximum lift amount of the low lift cam 13 is larger than the minimum lift amount of the high lift cam 14. And, even if the working angle is narrowed (see FIG. 26).
2 times the angle φ), and the opening areas of the low lift cam 13 at the maximum lift and the high lift cam 14 at the minimum lift are set to be substantially the same.

As a result, since there is almost no output difference at the time of switching, smooth switching can be performed. Further, it is possible to reduce mechanical loss due to the mirror cycle, improve efficiency, improve fuel efficiency, and improve durability because there is no impact at the time of switching.

Further, in the above case, the lift characteristics of the left and right valves may be changed, that is, the lift amount, working angle, timing, etc. may be different. As a result, the swirl or tumble flow is strengthened, and fuel efficiency can be significantly improved by lean burn.

Although the present invention has been described above with reference to various embodiments, the present invention is not limited to these embodiments, and modifications and the like can be made within the scope of the present invention.
The device of the present invention includes a plurality of main units (cam / camshaft unit 10, tappet unit 20, valve unit 30, rocker arm unit 40 (or swing arm unit 80) and accelerator shaft unit 50). Then, it explained with the example of those typical combinations. In addition to the case of these embodiments, the respective main units can be appropriately combined and changed, and in each case, the same operational effect as the above embodiments can be obtained.

The specific numerical values and the like described in the above embodiment are not necessarily limited to these, and can be changed as necessary. Further, in each of the embodiments, an example in which a two-cylinder engine is used has been described.
It can be effectively applied to engines having more than cylinders.

[0136]

As described above, according to the present invention, by rotating the valve lifter holding member in accordance with the accelerator opening degree in this type of engine, the sliding contact position with the rocker arm is continuous and stepless. Can be changed to. Thereby, the lift amount of the intake valve can be continuously changed. In this case, the valve lift can be switched at the optimum timing in the low speed range and the medium and high speed range, and the valve lift amount can be smoothly and properly controlled in a wide range from the idling speed range to the maximum speed range to improve fuel consumption and output. And so on.

[Brief description of drawings]

FIG. 1 is a perspective view showing a configuration of a main part of an engine provided with a valve gear according to the present invention.

FIG. 2 is a diagram showing an engine of a motorcycle according to an application example of the present invention.

FIG. 3 is a side sectional view of the main part of the valve gear of the present invention.

4 is a sectional view taken along the line AA of FIG.

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

FIG. 6 is a diagram showing a rotary drive system of a camshaft according to the valve gear of the present invention.

FIG. 7 is a perspective view showing a rocker arm according to the valve gear of the present invention.

FIG. 8 is a plan sectional view of a main part according to a second embodiment of the present invention.

FIG. 9 is a cross-sectional view of main parts according to a second embodiment of the present invention.

FIG. 10 is a sectional view taken along the line CC of FIG. 9 showing a guide mechanism of a cam phase varying device according to a second embodiment of the present invention.

FIG. 11 is a side sectional view of a main part according to a third embodiment of the present invention.

12 is a cross-sectional view taken along the line DD of FIG.

13 is a cross-sectional view taken along the line EE of FIG.

FIG. 14 is a view showing a holding fork according to a third embodiment of the present invention.

FIG. 15 is a diagram showing a phase relationship of a tappet or the like according to a third embodiment of the present invention.

FIG. 16 is a view showing the vicinity of an exhaust side tappet according to a third embodiment of the present invention.

FIG. 17 is a side sectional view of a main part according to a fourth embodiment of the present invention.

18 is a cross-sectional view taken along the line GG of FIG.

19 is a cross-sectional view taken along the line HH of FIG.

FIG. 20 is a diagram showing a phase relationship of a tappet or the like according to a fourth embodiment of the present invention.

FIG. 21 is a diagram showing the relationship between the tappet phase and the lift amount according to the fourth embodiment of the present invention.

FIG. 22 is a side sectional view of a main part according to a fifth embodiment of the present invention.

23 is a cross-sectional view taken along the line I-I of FIG.

24 is a cross-sectional view taken along the line JJ of FIG.

FIG. 25 is a diagram showing a guide mechanism of a cam phase varying device according to a fifth embodiment of the present invention.

FIG. 26 is a diagram showing the relationship between the tappet phase and the lift amount according to the fifth embodiment of the present invention.

[Explanation of symbols]

1 engine 2 cylinder head 3 pistons 4 drive sprocket 5 chains 6 Chain guide 7 Chain tensioner 8 chain adjuster 10 Cam / camshaft unit 11 camshaft 12 bearings 13 cams 20 tappet unit 21,22 tappets 23 Retainer holder 24 retainer 30 valve unit 31 intake valve 32 Valve guide 33 Tappet Sim 34 Tappet retainer 35 spring seat 36 valve spring 40 rocker arm unit 41,42 rocker arm 43 shaft 44 Stopper 50 accelerator shaft unit 51 accelerator shaft 52 gears 53 Driven gear 54 accelerator motor 55 drive gear 60 Phase sensor unit 61 pin 62 Phase sensor 70 Cam phase variable device 80 Swing arm unit 81,82 Swing arm 100 motorcycle 101 body frame 103 front fork 104 handlebar 106 front wheel 112 chains 116 Exhaust pipe 117 Fuel tank 118 sheets 120 headlamps

Continued front page    F-term (reference) 3G016 AA02 AA08 AA15 AA19 BA03                       BA06 BA18 BA23 BA24 BA28                       BA36 BA40 BB03 BB07 BB11                       BB17 CA10 DA01 DA06 DA22                 3G018 AB04 BA18 BA24 BA32 BA33                       CA02 CA20 DA10 DA17 DA74                       EA11 FA01 FA06 FA07 GA06                       GA07

Claims (13)

[Claims] 1. A rocker arm having a camshaft, a substantially disk-shaped valve lifter that is moved forward and backward by a cam of the camshaft, and a rocker arm that is slidably contactable with the valve lifter and is swingable. A valve operating device for moving the valve back and forth by means of: the valve lifter being held by a valve lifter holding member so as to be relatively movable around the cam shaft,
A valve train for an internal combustion engine, wherein a sliding contact position with the rocker arm can be continuously and steplessly changed by rotating the valve lifter holding member according to an accelerator opening. 2. A high lift valve lifter and a low lift valve lifter are provided for each cylinder, and a predetermined phase difference is set on the valve lifter holding member so that these valve lifters do not come into sliding contact with the rocker arm at the same time. The valve operating system for an internal combustion engine according to claim 1, wherein 3. The internal combustion engine according to claim 1, wherein the cam shaft is controlled so as to be movable in the circumferential direction relative to the driven sprocket of the cam chain in accordance with the accelerator opening degree. Valve device. 4. The valve lifter is forcibly moved in a direction away from the cam surface when sliding contact with the cam is not selected.
A valve operating system for an internal combustion engine according to any one of 1. 5. The valve lifter is always urged radially outward of the camshaft by an elastic member,
The valve lifter holding member has a substantially U-shaped groove formed at a position corresponding to each valve lifter, and the U-shaped groove is opened toward a radially inner side of the camshaft. 5. A valve train for an internal combustion engine according to item 4. 6. The valve lifter holding member pivotally supports the valve lifter in a substantially U-shaped groove provided at a position corresponding to each valve lifter, and holds the valve lifter so as to be able to move back and forth along the U-shaped groove, A valve lifter holding fork that covers a part of the valve lifter holding member is formed in a substantially arc shape, and an opening and an inclined surface are formed in the inner peripheral side bottom surface of the valve lifter holding fork, and the inclined surface and the bottom surface are The valve operating system for an internal combustion engine according to claim 4, wherein the valve lifter is configured to be able to ride up. 7. The low lift valve lifter is slidably in contact with one rocker arm, and the high lift valve lifter is slidably in contact with one and the other rocker arms. A valve operating system for an internal combustion engine according to any one of 1. 8. A set of a low lift valve lifter and a high lift valve lifter is provided so as to be capable of sliding contact with one rocker arm, and the high lift valve lifter and a separate high lift valve lifter are in sliding contact with the other rocker arm. The valve operating system for an internal combustion engine according to any one of claims 1 to 6, wherein the valve operating device is arranged so as to be possible. 9. The internal combustion engine according to claim 1, wherein a plurality of valve lifters having different lift amounts are provided for at least a low lift and a high lift per valve. Valve drive. 10. The valve operating system for an internal combustion engine according to claim 3, wherein the camshaft is controlled so as to be relatively movable in the circumferential direction by increasing or decreasing the hydraulic pressure. 11. The valve operating system for an internal combustion engine according to claim 3, wherein the camshaft is mechanically controlled to be movable in the circumferential direction in synchronization with the switching of the valve lifter. 12. An internal combustion engine in which intake and exhaust are controlled by an intake valve and an exhaust valve, the valve operating device according to claim 1 being provided on at least an intake side. Characterized internal combustion engine. 13. A steering head pipe rotatably supporting a front fork, a fuel tank mounted on a vehicle body frame connected to the steering head pipe, and a seat continuously provided behind the fuel tank. In a motorcycle having an air cleaner arranged below the seat and the fuel tank, an intake pipe mounted in front of the air cleaner and connecting the rear part and the air cleaner to the opposite side to the intake pipe. An internal combustion engine having an exhaust pipe coupled to a camshaft, a substantially disk-shaped valve lifter that moves forward and backward by a cam of the camshaft, and a rocker arm that is slidable and swingable with the valve lifter. And a valve operating device for moving the valve forward and backward by rocking the rocker arm, wherein the valve operating device includes: The lube lifter is held by a valve lifter holding member so as to be relatively movable around the cam shaft, and by rotating the valve lifter holding member according to an accelerator opening degree, a sliding contact position with the rocker arm is continuous. The internal combustion engine is characterized by being able to change steplessly.