JP2003201814A - Valve system of 4-cycle engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve engine characteristics, fuel consumption efficiency, durability, a high rotational follow-up property, etc. <P>SOLUTION: This valve system of the 4-cycle engine is provided with a fulcrum member 28 to rotate around a fulcrum revolution shaft 29, and a first actuator 32 to rotate this fulcrum member 28. A tip of the fulcrum member 28 is arranged between a force point and a working point of the rocker arm to make a fulcrum of the rocker arm 26. A valve lift quantity of the suction valve 11 is varied by rotating the supporting member 28. Further, two suction cams 17, 18 having different cam profiles for each of cylinders are provided, and two pressure rollers 58, 59 corresponding to the cylinders are also provided. One of the rollers is selectively inserted between one of the two suction cams 17, 18 and the force point of the rocker arm 26 by a second actuator 62. By this arrangement, the rocker arm 26 is driven along a cam profile of only a selected suction cum to lift the suction valve 11. <P>COPYRIGHT: (C)2003,JPO

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 a reciprocating four-cycle engine for a vehicle, in which a valve lift amount of an intake valve is variable.

[0002]

2. Description of the Related Art In an existing vehicle reciprocating 4-cycle engine, an intake cam provided on an intake cam shaft controls the opening and closing of an intake valve at a predetermined timing, and the lift amount of the intake valve depends on the height of the peak of the intake cam. (Valve opening amount) has been determined. Therefore, the valve lift amount is always constant regardless of the engine operating condition. The engine output is adjusted by changing the opening amount of the throttle valve installed in the intake passage on the upstream side of the intake valve.

[0003]

However, since the output of the engine is adjusted by changing the valve opening amount of the throttle valve installed in the intake passage on the upstream side of the intake valve as described above, the throttle valve itself is used. It becomes a resistance inside, and the charging efficiency of fresh air is reduced, which adversely affects the engine characteristics such as output and torque.

Moreover, when idling or running at low load,
Even when the engine does not require a large amount of fresh air, such as when the throttle is off (when the engine brake is used), the intake valve is fully opened and fresh air is drawn into the cylinder, resulting in lower output due to pumping loss. However, the reduction in fuel efficiency could not be ignored.

Further, at the time of idling or running at a low load, it is not necessary to open the valves so much, but the valves are completely pushed open against the urging force of the strong valve springs. Therefore, the rotation resistance of the engine is large, which also leads to a reduction in fuel efficiency, and also causes a reduction in engine durability due to generation of engine noise and wear of parts.

The present invention has been made to solve this problem, and aims to improve engine characteristics such as output and torque, as well as fuel efficiency, engine durability (reliability), and high rotation followability. , Engine noise reduction, structural simplification,
It is an object of the present invention to provide a valve train for a four-cycle engine that is lightweight and compact, and is excellent in manufacturability.

[0007]

In order to achieve the above object, a valve operating system for a four-cycle engine according to the present invention, as set forth in claim 1, presses a force point of a rocker arm with an intake cam, thereby rocking the rocker arm. In a valve operating system of a 4-cycle engine configured to lift an intake valve at an action point of an arm, a fulcrum member that rotates about a fulcrum rotation shaft that is parallel to an intake cam shaft, and a fulcrum member that rotates. A first actuator is provided, and the tip of the fulcrum member is arranged between the force point and the action point of the rocker arm, and this is used as the fulcrum of the rocker arm. By rotating the fulcrum member, the force point and the action point And the valve lift amount of the intake valve is changed by moving the fulcrum position between and, and two intake cams with different cam profiles per cylinder are arranged side by side on the intake cam shaft. Then, two pressing rollers are provided corresponding to these two intake cams, and one of the two pressing rollers is selectively placed between one of the two intake cams and the force point of the rocker arm by the second actuator. By inserting, the rocker arm is driven along the cam profile of only the selected intake cam to lift the intake valve.

According to the above arrangement, the valve lift amount can be freely changed from substantially zero or the idle lift amount to the maximum lift amount by operating the first actuator.
Instead of the conventional throttle control, the valve lift amount control itself is used as the throttle control, which eliminates the conventional throttle valve installed in the intake passage upstream of the intake valve and eliminates the resistance in the intake passage. It is possible to improve the charging efficiency of fresh air, delete unnecessary intake strokes and compression strokes to reduce pumping loss, and significantly improve engine characteristics such as output and torque and fuel efficiency. Moreover, by operating the second actuator, two intake cams having different cam profiles can be selectively used as the low-medium speed intake cam and the high-speed intake cam, so that the intake and exhaust valve opening overlaps in the low-medium speed range. The fuel efficiency can be further improved by reducing or eliminating the amount.

Further, in the valve train for a four-cycle engine according to the present invention, as described in claim 2, one roller operation shaft is provided with two eccentric cams having different eccentric directions so as to rotate integrally. The two pressing rollers are attached to the eccentric cam, and the roller operating shaft is rotated by the second actuator to move the two pressing rollers forward and backward with respect to the corresponding two intake cams at different timings. The pressing force of the intake cam on which the roller advances advances the rocker arm through the pressing roller. As a result, the structure is simplified, and the manufacturability is improved and the weight is reduced.

Further, in the valve train for a four-cycle engine according to the present invention, as described in claim 3, the rotation phase angle between the intake cam shaft and the driven sprocket for rotationally driving the intake cam shaft is set. A variable valve timing mechanism to change is provided. In this way, in addition to the effect of claim 1, the fuel efficiency in the low and medium speed range can be improved.

According to a fourth aspect of the present invention, there is provided a valve operating system for a four-cycle engine, which is located between the rocking point and the action point of the rocker arm along the rotation locus of the tip of the fulcrum member. An arc-shaped fulcrum section is formed, and the tip of the fulcrum member is brought into contact with this fulcrum section to make this abutment position a fulcrum position. By rotating the fulcrum member within the fulcrum section, the fulcrum position is changed and intake is performed. The valve lift amount of the valve is variable. Since this structure has a simple structure,
It can contribute to the improvement of reliability (durability) and manufacturability.

Further, in a valve train for a four-cycle engine according to the present invention, as described in claim 5, a pivot shaft parallel to the intake cam shaft is provided in an intermediate portion of the rocker arm, and the pivot shaft is attached to the pivot shaft. The rocker arm is slidably held along a direction substantially connecting the pressing roller and the tip of the intake valve, and the rocker arm is rotatable about a pivot axis, and the rotation of the fulcrum member is a sliding movement of the rocker arm. The tip of the fulcrum member is slider-connected to the pivot shaft so as to be converted into a flat slipper surface on the side opposite to the fulcrum member of the rocker arm, and the slipper surface is used as the pressing roller and the tip of the intake valve. The point of contact is the point of contact of the pressure roller with the slipper surface, and the point of action is the position of the tip of the intake valve with the slipper surface. As a result, not only the manufacturability of the rocker arm is improved, but also the rocker arm can be made lighter, so that the inertial weight of the rocker arm can be reduced and the high rotation followability of the engine can be enhanced.

Further, in the valve train for a four-cycle engine according to the present invention, as described in claim 6, the relative angle between the slipper surface and the axial direction of the intake valve when the intake valve is closed is a right angle. Set to less than. This makes it possible to reduce bending stress on the valve shaft near the time of maximum valve lift of the intake valve, prevent wear of the valve shaft and the valve guide, and improve reliability.

In the four-cycle engine valve operating system according to the present invention, as described in claim 7, since the oil supply passage communicating with the portion for slidably holding the pivot shaft is provided, the rocker arm of the rocker arm is provided. The fulcrum portion and the slide holding portion can be lubricated at the same time, and the structure can be simplified.

Further, in the valve operating system for a four-cycle engine according to the present invention, as described in claim 8, a pivot shaft parallel to the intake cam shaft is provided in an intermediate portion of the rocker arm, and the pivot shaft Both ends are held by the tip of the fulcrum member to allow the rocker arm to rotate about the pivot axis, and a slipper having an arc surface centering on the fulcrum pivot axis of the fulcrum member on the side opposite to the rocker arm. Surface is formed, and the slipper surface is brought into contact with the pressing roller and the tip of the intake valve, and the position where the pressing roller comes into contact with the slipper surface is the force point, and the position where the tip of the intake valve comes into contact with the slipper surface acts. It was a point.

With the above structure, the play of the rocker arm is reduced to reduce the weight of the rocker arm and to improve the manufacturability, and the position of the intake cam is brought closer to the top of the valve shaft to improve the layout property of the intake port. The processing of the arm can be facilitated.

Further, in the valve train for a four-cycle engine according to the present invention, as described in claim 9, the actuator of the fulcrum member and its drive portion are provided with a timing chain for rotationally driving the intake cam shaft and the timing chain. Since the fulcrum member and the rotation detecting means of the intake camshaft are arranged near the engine end portion on the opposite side, the engine size can be made compact.

Further, in the valve train for a four-cycle engine according to the present invention, as described in claim 10, since the urging means for lightly pressing the pressing roller against the intake cam is provided, it is possible to achieve high rotation followability. It can contribute to the improvement of quietness.

Further, in the valve train for a four-cycle engine according to the present invention, as described in claim 11, the arc radius of the slipper surface of the rocker arm is slightly increased from the action point side to the force point side. Since it is gradually changed so that the rocker arm is prevented from rattling when the valve lift amount is small, engine noise can be reduced and the valve lift amount can be accurately maintained.

Further, in the valve train of the four-cycle engine according to the present invention, as described in claim 12, the intake valve and the intake port opened and closed by the intake valve are
Two cylinders are provided for each cylinder, each intake valve is lifted by a separate rocker arm, and the power points of these two rocker arms are arranged along the axial direction of the intake cam shaft. The pressure roller that can press only the force point of one rocker arm, the other intake cam and the corresponding pressure roller can press the force point of both rocker arms at the same time, and the intake air that can press only one rocker arm The cam is a low-medium speed intake cam, and the intake cam that can press both rocker arms is a high-speed intake cam.

As a result, the intake port passage area can be reduced by closing one of the intake ports in the low and medium speed range, so that the output characteristics and fuel efficiency can be improved. Further, at that time, the air-fuel mixture sent from the intake port arranged offset with respect to the cylinder axis forms a swirl flow, so that lean combustion is possible, and fuel efficiency can be improved also in this respect.

According to a four-cycle engine valve operating system of the present invention, as described in claim 13, the valve opening angle of the low-medium speed intake cam is greater than the valve opening angle of the high-speed intake cam. Since the setting is made small, it is possible to further improve the output characteristics and fuel efficiency in the low and medium speed range.

According to the four-cycle engine valve operating system of the present invention, as described in claim 14, of the two intake ports, the passage area of the intake port that is open in both the low and medium speed range and the high speed range. Is set to be smaller than the passage area of the intake port that is opened only in the high speed range, so that the output characteristics and the fuel efficiency in the low and middle speed range can be further improved.

Further, in the valve train for a four-cycle engine according to the present invention, as described in claim 15, one of the two intake ports is formed substantially parallel to the cylinder axis, The other intake port was formed substantially at right angles to the cylinder axis. Thereby, the air-fuel mixture sent from the intake port substantially parallel to the cylinder axis forms a tumble flow, and the air-fuel mixture sent from the intake port substantially perpendicular to the cylinder axis forms a swirl flow.
The stirring action of the air-fuel mixture in the cylinder is enhanced, which enables lean combustion and improves fuel efficiency.

In the four-cycle engine valve operating system according to the present invention, as described in claim 16, since the intake port that opens in the low and medium speed range is formed substantially parallel to the cylinder axis, a low speed operation is achieved. It is possible to reduce the inflow resistance of the air-fuel mixture in the region and further improve the output characteristics and the fuel efficiency in the low and medium speed regions.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a vertical cross-sectional view of a cylinder head 1 showing a first embodiment of a four-cycle engine for vehicles to which a valve operating system according to the present invention is applied, and FIGS. 2 and 3 are II-II lines of FIG. 1, respectively. And a vertical sectional view taken along the line III-III, and FIG. 4 is a view on arrow IV in FIG.

This engine is, for example, an in-line two-cylinder,
A DOHC engine in which an intake port 3 and an exhaust port 4 communicate with the combustion chamber 2 of the cylinder head 11 from opposite directions, and an intake cam shaft 5 is provided above the intake port 3 and an exhaust cam shaft 6 is provided above the exhaust port 4. Is. The intake camshaft 5 includes four cam bearings 7 formed on the cylinder head 1.
a to 7d and the ball bearing 8, and the exhaust cam shaft 6 is similarly supported. An ignition plug 9 is arranged in the center of the combustion chamber 2, and a head cover 10 is liquid-tightly mounted on the upper portion of the cylinder head 1.

An intake valve 11 and an exhaust valve 12 are slidably provided in the intake port 3 and the exhaust port 4 by cylindrical valve guides 13 and 14, respectively, and these valves 11 and 12 are valve springs 15 and 16, respectively. Is always biased toward the valve closing direction. The structure around this valve is the same as that of a known 4-cycle engine.

The intake port 3 has one inlet, but is branched into a fork in the middle to be connected to the combustion chamber 2, and an intake valve 11 is provided at the end portion thereof. Therefore, 1
Two intake valves 11 are arranged per combustion chamber 2 side by side along the axial direction of the intake camshaft 5. Exhaust port 4
The exhaust valve 12 has the same configuration.

On the intake camshaft 5, two intake cams having different cam profiles per cylinder, that is, a low-medium speed intake cam 17 and a high-speed intake cam 18 are arranged side by side, and the movements of these cams 17, 18 are arranged. Is transmitted to each intake valve 11 via a substantially bifurcated rocker arm 26 and a pressing roller described later, and the intake valve 11 is opened and closed at a predetermined timing. The movement of the exhaust cam 19 also provided on the exhaust cam shaft 6 is transmitted to the exhaust valve 12 via the rocker arm 20, and the exhaust valve 12 is opened and closed at a predetermined timing.

A driven sprocket 21 is provided at one end of each of the intake camshaft 5 and the exhaust camshaft 6 (the exhaust camshaft 6 side is not shown), and timing is provided around the driven sprocket 21 and a drive sprocket of a crankshaft (not shown). The chain 22 is wound around and half of the crankshaft
The intake cam shaft 5 and the exhaust cam shaft 6 are rotationally driven at the rotational speed of.

Driven sprocket 2 on the intake camshaft 5 side
1 is provided with a variable valve timing mechanism 23. This mechanism is of a known type that operates by hydraulic pressure or the like, and changes the rotational phase angle between the intake camshaft 5 and the driven sprocket 21.

The rocker arm 20 on the exhaust side is a general seesaw type, and a pivot part 20a in the middle thereof is swingably supported by a rocker shaft 24, and a peak of the exhaust cam 19 is formed on a slipper surface 20b which is a power point. When pressed, the tappet portion (adjustment portion) 20c, which is the point of action, pushes down the upper end of the stem (shaft) of the exhaust valve 12, and opens the exhaust valve 12 against the biasing force of the valve spring 16.

On the other hand, the intake side rocker arm 26 has a shape different from that of the exhaust side rocker arm 20 and does not have a rocker shaft, and a slipper surface 26a provided as a force point at one end of the rocker arm 26 will be described in detail later. Pressing rollers 58, 59
Via low-medium speed intake cam 17 or high-speed intake cam 1
2 applied to the top of 8 and as the point of action at the other end
One tappet portion (adjustment portion) 26b abuts on the top portions (top end portions of the stems) of the two intake valves 11, 11 via shims 27. Width W1 of slipper surface 26a (see FIG. 4)
Is set to be equal to or slightly wider than the outer width W2 (see FIG. 3) of the low-medium speed intake cam 17 and the high-speed intake cam 18.

An arcuate fulcrum section 26c is provided on the upper surface of the intermediate portion of the rocker arm 26, and a lever-like fulcrum member 28 is provided above it. The fulcrum member 28 is integrally formed with, for example, a hollow shaft-shaped fulcrum rotation shaft 29, and the fulcrum rotation shaft 29 has four cams together with the intake cam shaft 5 so that the rotation axis line thereof is parallel to the intake cam shaft 5. Bearing 7
It is rotatably supported by a to 7d.

A worm wheel 31 is fixed to one end of the fulcrum pivot shaft 29, while a servo motor 32 is provided on the head cover 10 as a first actuator, and a worm gear 33 formed on the main shaft of the servo motor 32 is provided. The fulcrum pivot shaft 29 and the fulcrum member 2 are engaged with the worm wheel 31 by the operation of the servo motor 32.
8 rotates.

The cylinder head 1 (cam bearing 7a) is provided with a rotation amount detection sensor 34 for directly detecting the rotation amount of the fulcrum rotation shaft 29, and below the rotation amount detection sensor 35 of the intake cam shaft 5. Is provided. The rotational speed detection sensor 35 detects the rotational speed of the intake cam shaft 5 by detecting the movement of a detection protrusion 36 provided at the end of the intake cam shaft 5.

The vicinity of the tip of the fulcrum member 28 is formed into a pair of flanges that sandwich the fulcrum section 26c of the rocker arm 26 without play, and a roller shaft 38 is installed between them to prevent the roller shaft 38 from coming off with an E ring 39 or the like. A cylindrical roller member 4040 is rotatably supported around 38,
The roller member 40 contacts the fulcrum section 26c of the rocker arm 26.

The arc surface shape of the fulcrum section 26c is the fulcrum member 2
Along the rotation trajectory of the tip of 8 (roller member 40),
The fulcrum member 28 rotates at an angle within the arc range of the fulcrum section 26c, and the position where the roller member 40 contacts the arc surface of the fulcrum section 26c becomes the fulcrum position of the rocker arm 26.

The intake camshaft 5 and the exhaust camshaft 6 are formed with oil passages 42 and 43 respectively in the shaft center portions thereof, and the fulcrum pivot shaft 29 is formed with an oil passage 44 in the shaft center portions thereof.
The oil passages 7e-7 are provided inside the two cam bearings 7a-7b.
h is formed. The oil discharged from the oil pump (not shown) is supplied to the oil passages 42, 43, 4
4, 7e to 7h, the bearings of the shafts 5, 6, 29 are lubricated. A part of the oil supplied to the oil passage 44 of the fulcrum rotation shaft 29 is supplied from the oil holes 45, 45 to the fulcrum member 2.
8 is supplied to the roller member 40 at the tip, and the roller member 4
0 and the fulcrum section 26c of the rocker arm 26 are lubricated.

On the other hand, as shown in FIGS. 1 and 3, on one side in the cylinder head 1, there are four cam bearings 7 each having a roller operation shaft 47 parallel to the intake cam shaft 5 and the fulcrum rotation shaft 29.
It is pivotally supported by a to 7d. The roller operating shaft 47 is a split shaft composed of five parts, and the crank arm 48, the first eccentric cam shaft 49, the connecting shaft 50, the second eccentric cam shaft 51, and the support shaft 52 are sequentially spline-fitted from the end. The crank arm 48, the connecting shaft 50, and the support shaft 52 are rotatably connected, and are rotatably supported by the cam bearings 7a to 7d.

The first eccentric cam shaft 49 and the second eccentric cam shaft 51.
Include two eccentric cams 54, which have different eccentric directions.
55 are integrally formed side by side in the axial direction. The roller arms 56 and 5 are respectively attached to the eccentric cams 54 and 55.
7 is rotatably supported and each roller arm 56, 57
The above-mentioned pressing rollers 58 and 59 are rotatably supported at the tip of the. In this way, the pressing rollers 58 and 59 are attached to the eccentric cams 54 and 55 via the roller arms 56 and 57.

A pair of roller arms 5 for each cylinder
The back surfaces of the rollers 6 and 57 are in close contact with each other, and a slide groove 61 formed in the back surface of one roller arm 56 along the lever longitudinal direction has a slide pin 62 protruding from the back surface of the other roller arm 57. By slidably fitting, relative rotation between the roller arms 56 and 57 is prevented.

The positions of the two pressing rollers 58 and 59 provided for each cylinder correspond to the positions of the low-medium speed intake cam 17 and the high speed intake cam 18 of the intake cam shaft 5, respectively. As shown in FIG. 1, a hydraulic cylinder 63 is provided as a second actuator, and its telescopic rod 64 is connected to the tip of the crank arm 48 of the roller operating shaft 47 via a link 65.

When the telescopic rod 64 of the hydraulic cylinder 63 contracts, the crank arm 48 of the roller operating shaft 47 is pulled to the high speed position 48a rotated toward the intake cam shaft 5 as shown in FIGS. The cam 55 rotates so as to project toward the high speed intake cam 18, and the pressing roller 5
9 is inserted between the high speed intake cam 18 and the slipper surface 26 a of the rocker arm 26. On the contrary, the eccentric cam 54
Is separated from the low / medium speed intake cam 17, and the pressing roller 58
Is separated from the space between the low-medium speed intake cam 17 and the slipper surface 26a, the pressing force of the high-speed intake cam 18 is transmitted via the pressing roller 59 to the slipper surface 26 of the rocker arm 26.
By pressing a, the rocker arm 26 is driven along the cam profile of only the high speed intake cam 18, and the intake valve 11 is lifted.

Further, the telescopic rod 6 of the hydraulic cylinder 63
4 extends, the crank arm 4 of the roller operating shaft 47
8 is pushed to the low / medium speed position 48b rotated to the side opposite to the intake cam shaft 5, whereby the eccentric cam 54 moves the low / medium speed intake cam 1
The pressure roller 58 rotates to the 7 side and the low-medium speed intake cam 1
7 and the slipper surface 26a of the rocker arm 26. On the other hand, the eccentric cam 55 is the high-speed intake cam 18
And the pressing roller 59 separates from between the high speed intake cam 18 and the slipper surface 26a, the pressing force of the low / medium speed intake cam 17 presses the slipper surface 26a of the rocker arm 26 via the pressing roller 58. The rocker arm 26 is driven along the cam profile of only the low / medium speed intake cam 17 to lift the intake valve 11.

In this way, by rotating the roller operating shaft 47 by the force of the hydraulic cylinder 63, the two pressing rollers 58 and 59 are different in timing with respect to the low / medium speed intake cam 17 and the high speed intake cam 18. As the pressure roller 58 or 59 moves forward and backward, the intake cam 17 for low and medium speeds
Alternatively, one of the high-speed intake cam 18 and the rocker arm 26
The rocker arm 26 is driven along the cam profile of only the selected intake cam 17 or 18 by being selectively inserted between the rocker arm 26 and the slipper surface 26a.
The intake valve 11 is lifted.

On the other hand, when the fulcrum member 28 is rotated by the power of the servo motor 32, the fulcrum position is changed between the force point (slipper surface 26a) and the action point (tappet portion 26b) of the rocker arm 26, and the rocker arm 26. And the valve lift amount of the intake valve 11 changes.

For example, when the fulcrum member 28 is at the position 28a shown by the solid line in FIG. 1, the lever ratio of the rocker arm 26 is minimized and the valve lift amount of the intake valve 11 is maximized, so that the intake valve 11 is sucked into the combustion chamber 2. As a result, the fuel output of the engine increases as the amount of fuel-air mixture increases. Further, when the fulcrum member 28 is at the position 28b shown by the chain double-dashed line in FIG. 1, the lever ratio of the rocker arm 26 is maximized and the valve lift amount of the intake valve 11 is minimized (zero or minute amount), so that combustion The amount of the fuel mixture taken into the chamber 2 is reduced and the engine output is reduced. Then, the fulcrum member 28 moves between the positions 28a and 28b, whereby the intake valve 11
The valve lift amount of changes infinitely and the output of the engine changes smoothly.

This engine has a control device (C
PU) is provided, and this control device controls the throttle opening input of the throttle device operated by the driver of the vehicle, the rotation amount of the fulcrum member 28 input from the rotation amount detection sensor 34, and the rotation speed detection sensor 35. The servo motor 32 is operated based on the input information such as the rotational speed of the intake camshaft 5 to set the engine output according to the driver's intention.

The control device controls the hydraulic cylinder 63 so that the low-medium speed intake cam 17 is selected during the low-medium speed operation and the high-speed intake cam 18 is selected during the high-speed operation. When the low-medium speed intake cam 17 is selected, the intake valve 11 is opened and closed at a valve timing suitable for the low-medium speed rotation range, and when the high-speed intake cam 18 is selected, the intake valve 1 is opened.
1 is opened and closed at a valve timing suitable for a high speed rotation range.

Further, the control device controls the variable valve timing mechanism 23 to the low and medium speed mode during the low and medium speed operation, and the variable valve timing mechanism 23 to the high speed mode during the high speed operation. For example, when the variable valve timing mechanism 23 switches from the low / medium speed mode to the high speed mode,
The rotation phase angle of the intake camshaft 5 with respect to the driven sprocket 21 is advanced, and intake timing for higher speed operation is set.

According to the structure of this valve operating device, the valve lift amount of the intake valve 11 can be smoothly varied from substantially zero or the idle lift amount to the maximum lift amount, so that the conventional throttle control is replaced. The control of the valve lift amount itself is throttle control, whereby the throttle valve conventionally installed in the intake passage on the upstream side of the intake valve 11 is omitted to eliminate the resistance in the intake passage. It is possible to improve the charging efficiency and dramatically improve engine characteristics such as output and torque.

Moreover, when idling or running at low load,
In an operating condition where a large amount of fresh air is not needed, such as when the throttle is off (when the engine brake is used), the opening amount of the intake valve 11 is reduced and the intake amount of fresh air is reduced, so pumping loss is reduced. The fuel efficiency can be improved by reducing the fuel consumption.

Further, since the opening amount of the intake valve 11 becomes small at the time of idling or running at a low load as described above, the amount by which the strong valve spring 15 is compressed becomes small, and the rotational resistance of the engine decreases accordingly. However, in this respect as well, it contributes to the improvement of fuel efficiency, wear of each component constituting the valve train is delayed, engine durability is improved, and the level of engine noise is also reduced.

Moreover, by operating the hydraulic cylinder 63, the low-medium speed intake cam 17 and the high-speed intake cam 18 having different cam profiles can be selectively used, and by operating the valve timing variable mechanism 23, the intake camshaft 5 and the driven sprocket can be operated. Since it is possible to change the rotation phase angle between the intake and exhaust valves 21, the valve opening overlap amount of the intake / exhaust valve 12 in the low / medium speed range is set small or set to zero, and the optimum lift according to the engine speed is set. The amount can be realized, and the fuel efficiency can be further improved.

On the other hand, in terms of the basic structure, as a structure for changing the fulcrum position of the rocker arm 26, an arcuate fulcrum section 26c is provided on the upper surface of the intermediate portion of the rocker arm 26, and the tip of the fulcrum member 28 is provided at this fulcrum section 26c. Since the (roller member 40) is abutted, the structure around the rocker arm 26 is simple, the reliability (durability) and the manufacturability are high, and it is possible to greatly contribute to the weight reduction and maintainability. high.

Further, the pressure roller 5 provided for selectively using the low-medium speed intake cam 17 and the high speed intake cam 18
8 and 59 are attached to two eccentric cams 54 and 55 provided on one roller operating shaft 47 and having different eccentric directions via roller arms 56 and 57.
The two pressure rollers 58 and 59 are driven to rotate by the force of the hydraulic cylinder 63, so that the low-medium speed intake cam 17 is moved.
And the intake cam 1 for the high-speed intake cam 18 at a different timing and the push rollers 58, 59 move forward.
Since the rocker arm 26 is driven by the pressing force of 7 or 18, this is also a very simple structure, and it is possible to improve the manufacturability and reduce the weight.

Further, in this engine, the fulcrum member 28
A servo motor 32 for driving (fulcrum pivot shaft 29),
A worm wheel 31 and a worm gear 33, which are the driving parts thereof, are arranged between the timing chain 22 and a cylinder adjacent thereto, while a fulcrum member 28 (fulcrum rotation shaft 29) is provided near the engine end on the opposite side. Intake camshaft 5
The rotation amount detection sensor 34 and the rotation speed detection sensor 35, which are the rotation detection means, are arranged. As a result, the dead space inside the cylinder head 1 can be effectively used to reduce the size of the engine.

FIG. 5 is a longitudinal sectional view of a cylinder head showing a second embodiment of the present invention, and FIG. 6 is a VI-VI of FIG.
It is a longitudinal cross-sectional view along a line. Here, since the configuration and operation other than the vicinity of the roller arms 68 and 69 are exactly the same as those of the first embodiment (FIGS. 1 and 3), the attachment and description of the reference numerals will be omitted except for a part. .

Here, the slide grooves 80, 81 and the slide pin 62 in the first embodiment are not provided on the back surface of each roller arm 68, 69, but instead on the shaft support portion of each roller arm 68, 69. Arm springs 70 and 71 are provided respectively. The arm springs 70, 71 are formed in a coil spring shape, and the coil portion is wound around the roller operation shaft 47, and the hooks 70a, 70b, 71a at both ends of the spring are formed.
71b are engaged with the shaft supporting portions 7a to 7d and the locking pins 72 and 73 projecting from the roller arms 68 and 69, respectively.

By the urging force of the arm springs 70 and 71, the pressing rollers 58 and 59 and the roller arm 6 are
8, 69 are low and medium speed intake cams 17 and high speed intake cams 18
Lightly pressed to the side, which allows the roller arm 6
The inertial weights of 8, 69 and the pressing rollers 58, 59 are carried by the arm springs 70, 71, and the valve springs 15, 15 are not burdened by that much. Therefore, the high rotation followability of the intake valves 11, 11 is improved. It is possible to prevent the pressing rollers 58, 59 and the roller arms 68, 69 from jumping to improve the quietness of the engine. In this way, the arm springs 70 and 71 function as a biasing means for the pressing rollers 58 and 59.

FIG. 7 is a longitudinal sectional view of a cylinder head showing a third embodiment of the present invention, and FIG. 8 is a line VIII- of FIG.
FIG. 9 is a vertical sectional view taken along the line VIII, and FIG. 9 is a view on arrow IX in FIG. 7. Again, the first and second embodiments (FIGS.
Parts having the same configurations as those in FIG. 6) are omitted except for some parts, and reference numerals are omitted.

Also in the third embodiment, the intake cam shaft 5 and the fulcrum pivot shaft 75 are rotatably supported by the four shaft supporting portions 7a to 7d provided on the cylinder head 1 as in the case of the first embodiment. On the other hand, a pivot shaft 7 parallel to the intake cam shaft 5 and the fulcrum pivot shaft 75 is provided in the middle of the intake side rocker arm 76.
7 is closely inserted, and both ends thereof are slide bearings 78, 79.
The slide bearings 78 and 79 are rotatably supported by the cam bearing 7.
It is fitted in slide grooves 80 and 81 formed on the surfaces of a and 7b facing the cam bearings 7c and 7d. The slide grooves 80 and 81 are used for the pressure rollers 58 and 59 and the intake valve 1.
Since the rocker arm 76 and the pivot shaft 77 are slidable in the same direction because they extend in a direction substantially connecting the tip of the rocker 1, the rocker arm 76 is rotatable around the pivot shaft 77.

The fulcrum members 82 and 83 are integrally formed with the fulcrum pivot shaft 75 similarly to the fulcrum member 28 of the first embodiment, but are formed into a pair of flat plates sandwiching the rocker arm 76 from both sides, A U-shaped slider notch 84 formed at the free end of each fulcrum member 82, 83 holds the pivot shaft 77 of the rocker arm 76 between the rocker arm 76 and the slide bearings 78, 79.

The pivot shaft 77 is a U-shaped slider notch 8
Because it can slide along the longitudinal direction of 4,
The tips of the fulcrum members 82 and 83 and the pivot shaft 77 are slider-connected, and the rotation of the fulcrum members 82 and 83 is converted into the sliding movement of the rocker arm 76, so that the rocker arm 7 is moved.
6 is a slide groove 80, together with slide bearings 78, 79.
Slide along 81.

On the other hand, the anti-fulcrum member 8 of the rocker arm 76
A flat slipper surface 76a is formed on the side of No. 2,83, and the slipper surface 76a is used as a pressure roller 58,
The position where the pressure rollers 58 and 59 come into contact with 59 and the tip of the intake valve 11 and the slipper surface 76a comes into contact is the force point, and the position where the tip of the intake valve 11 comes into contact is the point of action. The tip of the intake valve 11 is in contact with the slipper surface 76a via the tappet adjust nut 85, and the valve gap (tappet clearance) can be adjusted by adjusting the tappet adjust nut 85.

The fulcrum members 82 and 83 (fulcrum pivot shaft 75) are driven by the power of the servo motor 32 to rotate as in the case of the first embodiment. When the fulcrum members 82 and 83 rotate, the rocker arm 76, which is slider-connected to the fulcrum members 82 and 83, slides along the slide bearings 78 and 79 along the slide grooves 80 and 81.
Since the position of the pivot shaft 77 changes between the pressure rollers 58 and 59, which are the input parts to the force point of 6, and the intake valve 11 (tappet adjust nut 85) corresponding to the point of action, the lever ratio of the rocker arm 76 is changed. As a result, the valve lift amount of the intake valve 11 changes.

For example, when the fulcrum members 82 and 83 are in the positions shown by the solid lines in FIG. 7, the lever ratio of the rocker arm 76 is minimized, the valve lift amount is maximized, and the engine output is increased. Further, the fulcrum members 82 and 83 are shown in FIG.
Rocker arm 7 when in the position shown by the chain double-dashed line
The lever ratio of 6 is maximized, the valve lift amount is minimized, and the engine output is reduced. And the fulcrum member 8
By rotating 2, 83, the valve lift amount of the intake valve 11 changes steplessly, and the output of the engine changes smoothly.

At the same time, similarly to the case of the first embodiment, the hydraulic cylinder 63 is controlled by a control device (not shown), the low / medium speed intake cam 17 is selected during low / medium speed operation, and the high speed intake cam is selected during high speed operation. The pressure rollers 58 and 59 are operated so that 18 is selected.

According to the structure of the third embodiment, since the slipper surface 76a of the rocker arm 76 is formed in a single plane shape, the manufacturability of the rocker arm 76 is improved, and at the same time, the rocker arm 76 can be made compact and compact. Since the weight can be reduced, the inertial weight of the rocker arm 76 is reduced, and the high rotation followability of the engine can be enhanced.

Further, since the pivot shaft 77 does not move in any direction other than its sliding direction, the slide bearings 78 and 79 supporting the pivot shaft 77 can be cylindrical bearings, whereby the pivot shaft 77 and the rocker arm are provided. The play (play) of 76 is suppressed as much as possible to make the behavior of the intake valve 11 accurate to suppress the generation of noise, and the wear of the pivot shaft 77 and the slide bearings 78, 79 is reduced to improve the durability of the engine. Can be increased.

By the way, as shown in FIG. 7, the relative angle (π-α) between the slipper surface 76a and the axial direction of the intake valve 11 when the intake valve 11 is closed is set to be less than a right angle. Desirably, the angle (π−α) is set to a right angle in the vicinity of the maximum valve lift of the intake valve 11.

This makes it possible to reduce bending stress on the valve shaft in the vicinity of the maximum valve lift of the intake valve 11, prevent wear of the valve shaft and the valve guide 13, and improve reliability.

Further, as shown in FIG. 8, the oil passages 87, 88 formed inside the cam bearings 7a, 7d for supporting the vicinity of both ends of the intake camshaft 5 have slide bearings 78, 79.
And the inner diameter of the pivot shaft 77. As shown in FIG. 9, the oil passages 87, 88 have short branch passages 89,
90 are orthogonal to each other, and the branch passages 89 and 90 are oil grooves 91 and 9 formed on the back surfaces of the slide bearings 78 and 79.
It communicates with 2. An oil hole 93 is formed in the pivot shaft 77.

The oil supplied to the oil passages flows in the order of the branch passages 89, 90 → the oil grooves 91, 92 → the inner diameter of the pivot shaft 77 → the oil hole 93, whereby the slide grooves 80, 81 and the slide bearings 78, 79. And between the pivot shaft 77 and the rocker arm 76 are satisfactorily lubricated.
If oil holes are also formed in the rocker arm 76, the cam surfaces of the intake cams 17 and 18 and the pressing rollers 58 and 5 can be formed.
It is possible to easily lubricate during 9 as well.

Thus, the fulcrum portion (pivot shaft 77) of the rocker arm 76 and the slide holding portion (slide bearing 7)
8, 79 and the slide grooves 80, 81) can be lubricated at the same time, so that the lubrication structure can be simplified and the manufacturability of the engine can be improved.

FIG. 10 is a vertical cross-sectional view of a cylinder head showing a fourth embodiment of the present invention, and FIG. 11 is an XI of FIG.
12 is a vertical cross-sectional view taken along the line -XI, and FIG. 12 is a view taken along the arrow XII in FIG. Also here, parts having the same configurations as those of the first to third embodiments (FIGS. 1 to 9) will not be attached with reference numerals and description thereof.

Also in the fourth embodiment, the pivot shaft 97 parallel to the intake cam shaft 5 and the fulcrum pivot shaft 96 is densely inserted in the middle portion of the intake side rocker arm 95. On the other hand, the fulcrum members 98 and 99 integrally formed with the fulcrum pivot shaft 96 are shaped like a pair of arms sandwiching the rocker arm 95 from both sides, and the pivot shaft 97 of the pivot shaft 97 is provided at the tip of each fulcrum member 98 and 99. Both ends are held. Rocker arm 9
5 is rotatable about a pivot shaft 97.

Anti-fulcrum members 98, 9 of the rocker arm 95
An arcuate slipper surface 95a is formed on the 9 side. The center of the arc of the slipper surface 95a is the fulcrum member 9
The axis of rotation of the fulcrum of 8, 99 is 96. The slipper surface 95a includes the pressure rollers 58, 59 and the intake valve 11.
The position where the pressure rollers 58 and 59 come into contact with the tip of the intake valve 11 and the slipper surface 95a comes into contact is the point of application, and the position where the tip of the intake valve 11 comes into contact is the point of action. Intake valve 1
The tip of No. 1 contacts the slipper surface 95a via the tappet adjust nut 100.

The fulcrum members 98 and 99 (fulcrum pivot shafts 96) are driven by the power of the servomotor 32 to rotate, and the rocker arm 95 connected to the fulcrum members 98 and 99 is accordingly rotated. Tip of (pivot shaft 9
It moves along the rotation trajectory drawn by 7). As a result, the position of the pivot shaft 97 changes between the pressure rollers 58 and 59 and the intake valve 11 (tappet adjust nut 100), so that the lever ratio of the rocker arm 95 is changed and the valve lift amount of the intake valve 11 is changed. Change.

For example, when the rocker arm 95 is at the position shown by the solid line in FIG. 10, the lever ratio of the rocker arm 95 is minimized and the valve lift amount is maximized. In the position shown by, the lever ratio of the rocker arm 95 is maximized and the valve lift amount is minimized. By moving the rocker arm 95 in this manner, the valve lift amount changes steplessly.

In the structure of the fourth embodiment, the rocker arm 95 is provided with the fulcrum members 98 and 99 via the pivot shaft 97.
Therefore, the structure around the rocker arm 95 can be greatly simplified, and the behavior of the intake valve 11 can be stabilized by minimizing the play (play) of the rocker arm 95. In addition, the rocker arm 95 can be made smaller and lighter, which can greatly contribute to the high rotation followability of the engine and the improvement in manufacturability. Further, since the slipper surface 95a of the rocker arm 95 is formed into a simple quadric surface, the workability of the rocker arm 95 is also good in this respect.

Further, since the rocker arm 95 is curved in a bow shape, the position of the intake cam 5 is brought closer to the shaft top of the intake valve 11 to improve the layout of the intake port 3 and improve the intake performance. be able to.

By the way, as shown in FIG. 13, the arc radius of the slipper surface 95a of the rocker arm 95 is gradually changed with respect to the original arc radius R so as to be slightly larger from the action point side toward the force point side. May be. Specifically, the radius R2 from the shaft center O to the vicinity of the force point is about several tens of microns larger than the radius R1 from the shaft center O of the fulcrum rotation shaft 96 to the vicinity of the action point when the intake valve 11 is closed. To be set.

As a result, an increase in valve clearance when the valve lift amount is small can be suppressed, engine noise can be reduced, and the valve lift amount can be accurately maintained. If the amount of gradual change of the arc radius of the slipper surface 95a is made proportional to the lever ratio of the rocker arm 95, the substantial valve clearance becomes constant regardless of the position of the rocker arm 95.

The oil passage 101 formed inside the fulcrum member 98 on one side of each cylinder is the oil passage 102 formed at the axial center of the fulcrum pivot shaft 96, and the pivot shaft 97.
Since the pivot shaft 97 is provided with an oil hole 103, the oil passage 102 → the oil passage 101 → the inner diameter portion of the pivot shaft 97 → the oil hole 10
The oil flows in the order of 3, so that the space between the pivot shaft 97 and the rocker arm 95 is satisfactorily lubricated.

FIG. 14 is a vertical sectional view of a cylinder head showing a fifth embodiment of the present invention, and FIG. 15 is an XV of FIG.
-Longitudinal sectional view taken along line -XV, FIG. 16 shows XVI-X in FIG.
FIG. 17 is a vertical sectional view taken along line VI, and FIG. 17 is a view taken in the direction of arrow XVII in FIG.

In the fifth embodiment, two intake valves 11 per cylinder are provided as in the first to fourth embodiments.
a and 11b are provided. However, the intake port is not bifurcated, and the intake valve 11a is provided with the intake port 3a, and the intake valve 11b is provided with the intake port 3b. The inlets of both intake ports 3a, 3b are formed in a substantially semicircular shape, and are adjacently opened to one side of the cylinder head 1.

The intake valves 11a and 11b are lifted by individual rocker arms 107a and 107b. Each rocker arm 107a, 107b has one pivot shaft 1
08, and a pair of arm-shaped fulcrum members 11 in which both ends of the pivot shaft 108 are integrally formed with the fulcrum rotation shaft 110.
It is held at 1,112. As shown in FIG. 17, the combined shape of the rocker arms 107a and 107b is
It is similar to the rocker arm 95 of the fourth embodiment shown in FIG.

On the sides of the rocker arms 107a and 107b opposite to the fulcrum member, there are slipper surfaces 107 each having an arc surface.
c, 107d are formed, and their arc centers serve as the axis of the fulcrum rotation shaft 110 (the intake valves 11a, 11d).
b) when closed. Slipper surface 107c is pressure roller 1
14 and the tip of the intake valve 11a, the slipper surface 107d abuts on the pressing roller 115 and the tip of the intake valve 11b, and the position of the slipper surfaces 107c and 107d where the pressing rollers 114 and 115 come into contact is the force point.
The position where the tips of the intake valves 11a and 11b contact each other is the point of action. The tips of the intake valves 11a and 11b are attached via a tappet adjust nut 127 to the slipper surface 107.
c, 107d, tappet adjust nut 12
By adjusting 7, the valve clearance (tappet clearance) is adjusted.

The power points of the rocker arms 107a and 107b are arranged along the axial direction of the intake cam shaft 5, and the intake cam shaft 5 is formed with a low / medium speed intake cam 117 in accordance with the power point position of the rocker arm 107a. Arm 107b
The intake cam 118 for high speed is formed according to the power point position of. Here, the valve opening angle of the low-medium speed intake cam 117 is
It is set smaller than the valve opening angle of the high speed intake cam 118.

The pressure roller 114 is interposed between the power point of the rocker arm 107a and the low-medium speed intake cam 117, and the pressure roller 115 is interposed between the power point of the rocker arm 107b and the high speed intake cam 118. The holding structure of the pressing rollers 114 and 115 is similar to that of the second embodiment and the like.

As shown in FIG. 16, low-medium speed intake cam 1
The width W3 of the high-speed intake cam 118 and the pressing roller 115 is set to be twice as wide as the width W3 of the pressing roller 114 and the pressing roller 114. Then, as shown in FIG. 17, the width W5 of the force point of the rocker arm 107a is determined by the pressure roller 1
The width of the rocker arm 107b is set so as to cover the entire width of 14 and half of the width of the pressing roller 115.
The width W6 of the force point is set to be narrow so as to cover only the remaining half width of the pressing roller 115.

Therefore, the low-medium speed intake cam 117 and the pressing roller 114 can press only the force point of one rocker arm 107a, and the high speed intake cam 118 and the pressing roller 115 both the rocker arms 107a, 10a.
The force points of 7b can be pressed simultaneously.

Similar to the first to fourth embodiments, the fulcrum pivot shaft 110 is driven by the servomotor 32 controlled by the control device to pivot, and the fulcrum member 11 is accordingly rotated.
Rocker arms 107a, 10 connected to 1, 112
7b is the tip of the fulcrum member 111, 112 (pivot shaft 1
08) to move along the rotation trajectory drawn. Therefore, the pressure rollers 114 and 115 and the intake valves 11a and 11b are
The position of the pivot shaft 108 changes with the (tappet adjust nut 116), and the rocker arms 107a, 1
The lever ratio of 07b is changed so that the intake valves 11a, 11
The valve lift amount of b changes.

Further, the control device inserts the pressing roller 114 between the low / medium speed intake cam 117 and the power point of the rocker arm 107a at the time of low / medium speed operation to select the low / medium speed intake cam 117. High speed intake cam 1 during operation
The hydraulic cylinder 63 is controlled so that the pressing roller 115 is inserted between the pressure point 18 and the rocker arm 107b to select the high-speed intake cam 118. The structure of the drive mechanism of the pressing rollers 114 and 115 is the same as that of the first embodiment and the like.

When the low / medium speed intake cam 117 is selected, the pressing force of the low / medium speed intake cam 117 is equal to the pressure roller 1.
The rocker arm 107a is swung via 14 to open / close the intake valve 11a at a valve timing suitable for a low / medium speed rotation range. At this time, since the pressing force of the high speed intake cam 118 is not applied to the rocker arm 107b, the movements of the rocker arm 107b and the intake valve 11b are stopped, and the intake port 3b remains closed. Therefore,
The air-fuel mixture is sucked into the cylinder only through the intake port 3a.

When the high-speed intake cam 118 is selected, the pressing force of the high-speed intake cam 118 is the pressing roller 1
Both rocker arms 107a and 107b are swung via 15 to open and close the intake valves 11a and 11b at a valve timing suitable for a high speed rotation range. Therefore, the air-fuel mixture is sucked into the cylinder from both the intake ports 3a and 3b. The rocker arm 107b is provided with a stopper 120 for restricting the swing range at the time of rest and for preventing noise generation.

With this construction, one intake port 3b is closed and the air-fuel mixture is sucked only from the air-intake port 3a in the low and medium speed range, so that the intake passage area of the air-fuel mixture is reduced and the output characteristics are reduced. And fuel efficiency can be improved. Further, at that time, the air-fuel mixture sent from the intake port 3a which is arranged offset with respect to the cylinder axis forms a swirl flow inside the cylinder, so that lean combustion becomes possible and fuel efficiency is improved in this respect as well. You can

Moreover, since the valve opening angle of the low-medium speed intake cam 117 is set to be smaller than the valve opening angle of the high-speed intake cam 118, it is possible to further improve the output characteristics and the fuel efficiency in the low-medium speed range. You can

In this embodiment, of the two intake ports 3a, 3b provided for each cylinder, the passage area of the intake port 3a, which is open in both the low and medium speed range and the high speed range, is open only in the high speed range. It is set smaller than the passage area of the intake port 3b. Specifically, the wall 121 that separates the intake ports 3a and 3b is arranged offset on the intake port 3a side. By doing so, it is possible to increase the flow velocity of the intake air-fuel mixture in the low to medium speed range, improve the combustion efficiency, and further improve the output characteristics and the fuel efficiency.

FIG. 18 is a vertical cross-sectional view of a cylinder head showing a sixth embodiment of the present invention, and FIG. 19 is an XI of FIG.
It is a longitudinal cross-sectional view taken along line X-XIX. In this sixth embodiment, two intake ports 3 are provided for each cylinder.
The configuration other than c and 3d and the head cover 10a is the same as that of the fifth embodiment.

Here, the intake port 3c is an intake port that is normally open in both the low and medium speed range and the high speed range, is formed substantially parallel to the cylinder axis, and its inlet is open on the upper surface of the head cover 10a. In addition, the intake port 3d
Is an intake port that is opened only in the high speed region, is formed substantially at a right angle to the cylinder axis, and its inlet opens on the side surface of the cylinder head 1. The control mode of the intake port 3d is the same as that of the fifth embodiment.

In this way, the air-fuel mixture sent from the intake port 3c forms a tumble flow in the cylinder,
Since the air-fuel mixture sent from the intake port 3d forms a swirl flow in the cylinder, the stirring action of the air-fuel mixture in the cylinder is enhanced, which enables lean combustion and greatly improves fuel efficiency. You can

Further, since the intake port 3c which opens in the low and medium speed range is formed substantially parallel to the cylinder axis,
By reducing the inflow resistance of the air-fuel mixture in the low speed range, it is possible to further improve the output characteristics and the fuel efficiency in the low and middle speed ranges.

[0107]

As described above, according to the present invention,
In addition to improving engine characteristics such as output and torque, fuel efficiency, engine durability (reliability) and high rotation followability, engine noise reduction, structural simplification, weight reduction, and compactness are achieved. It is possible to improve manufacturability and the like.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a cylinder head showing a first embodiment of a vehicle 4-cycle engine to which a valve operating system according to the invention is applied.

FIG. 2 is a vertical cross-sectional view taken along the line II-II of FIG.

FIG. 3 is a vertical cross-sectional view taken along the line III-III in FIG.

FIG. 4 is a view on arrow IV in FIG. 1.

FIG. 5 is a vertical cross-sectional view of a cylinder head showing a second embodiment of the present invention.

6 is a vertical cross-sectional view taken along the line VI-VI of FIG.

FIG. 7 is a vertical cross-sectional view of a cylinder head showing a third embodiment of the present invention.

8 is a vertical cross-sectional view taken along the line VIII-VIII in FIG.

FIG. 9 is a view on arrow IX in FIG. 7.

FIG. 10 is a vertical cross-sectional view of a cylinder head showing a fourth embodiment of the present invention.

11 is a vertical cross-sectional view taken along the line XI-XI of FIG.

FIG. 12 is a view on arrow XII of FIG.

FIG. 13 is a view showing an arc shape of a slipper surface of a rocker arm.

FIG. 14 is a vertical sectional view of a cylinder head showing a fifth embodiment of the present invention.

15 is a vertical cross-sectional view taken along the line XV-XV in FIG.

16 is a vertical cross-sectional view taken along the line XVI-XVI of FIG.

FIG. 17 is a view on arrow XVII in FIG.

FIG. 18 is a vertical sectional view of a cylinder head showing a sixth embodiment of the present invention.

19 is a vertical sectional view taken along line XIX-XIX in FIG.

[Explanation of symbols]

1 cylinder head 11 Intake valve 17,18 intake cam 26 rocker arms 28 fulcrum member 29 fulcrum rotation axis 32 Servo motor which is the first actuator 58,59 Pressing roller 63 Hydraulic cylinder which is the second actuator

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) F02F 1/42 F02F 1/42 FF term (reference) 3G016 AA08 AA19 BA03 BA18 BA28 BB11 BB16 BB17 BB19 BB22 BB26 DA08 GA06 3G018 AA05 AB05 BA07 BA10 BA17 BA19 CA02 CA07 CA13 CA19 DA11 FA03 FA06 FA07 GA04 GA07 3G024 AA09 DA01 DA03 DA06 DA10 DA18

Claims (16)

[Claims] 1. A valve operating system for a 4-cycle engine configured to press a force point of a rocker arm with an intake cam and lift an intake valve at an action point of the rocker arm, thereby rotating a fulcrum parallel to an intake cam shaft. A fulcrum member that rotates about an axis and a first actuator that rotates the fulcrum member are provided, and the tip of the fulcrum member is arranged between the force point and the action point of the rocker arm to lock the rocker arm. By using the arm as a fulcrum, by rotating the fulcrum member, the fulcrum position is moved between the force point and the action point to change the valve lift amount of the intake valve, and two intake cams having different cam profiles per cylinder are provided. They are arranged side by side on the intake cam shaft, two pressing rollers are provided corresponding to these two intake cams, and one of the two pressing rollers is connected to the second actuator. The rocker arm is driven along the cam profile of only the selected intake cam to lift the intake valve by selectively inserting it between one of the two intake cams and the power point of the rocker arm by the motor. A valve operating system for a four-cycle engine, which is characterized in that 2. One roller operating shaft is provided with two eccentric cams having different eccentric directions so as to rotate integrally, and these two pressing rollers are attached to these eccentric cams, respectively, and the roller operating shaft is connected to the second roller operating shaft. The two pressing rollers are moved forward and backward with respect to the corresponding two intake cams at different timings by rotationally driving the actuator, and the pressing force of the intake cam on which the pressing roller advances advances the rocker arm through the pressing rollers. The valve train for a four-cycle engine according to claim 1, wherein the valve train is driven. 3. A valve operating system for a four-cycle engine according to claim 1, further comprising a variable valve timing mechanism for changing a rotational phase angle between the intake cam shaft and a driven sprocket that rotationally drives the intake cam shaft. . 4. An arc-shaped fulcrum section is formed between the force point and the action point of the rocker arm along the rotation locus of the tip of the fulcrum member, and the tip of the fulcrum member is brought into contact with this fulcrum section. The four-cycle engine according to claim 1, wherein the contact portion is set as a fulcrum position, and the fulcrum member is rotated within the fulcrum section to change the fulcrum position to change the valve lift amount of the intake valve. Valve drive. 5. A pivot shaft parallel to the intake cam shaft is provided at an intermediate portion of the rocker arm, and the pivot shaft is slidably held along a direction substantially connecting the pressing roller and a tip of the intake valve. The rocker arm is rotatable around the pivot shaft, and the tip of the fulcrum member is connected to the pivot shaft by a slider so that the rotation of the fulcrum member is converted into the sliding motion of the rocker arm. A flat slipper surface is formed on the side opposite to the fulcrum member, and the slipper surface is brought into contact with the pressing roller and the tip of the intake valve, and the position where the pressing roller comes into contact with the slipper surface is the force point, and the intake valve is provided on the slipper surface. The position where the tip of the abutment is in contact is the point of action.
4. A valve train for a 4-cycle engine according to item 4. 6. The valve operating system for a four-cycle engine according to claim 5, wherein the relative angle between the slipper surface and the axial direction of the intake valve when the intake valve is closed is set to less than a right angle. 7. The valve operating system for a four-cycle engine according to claim 5, further comprising an oil supply passage communicating with a portion that slidably holds the pivot shaft. 8. A pivot shaft parallel to the intake cam shaft is provided at an intermediate portion of the rocker arm, and both ends of the pivot shaft are held by tips of the fulcrum member, and the rocker arm is rotatable about the pivot shaft. At the same time, on the side of the rocker arm opposite to the fulcrum member, an arc-shaped slipper surface centered on the fulcrum pivot axis of the fulcrum member is formed, and the slipper surface is brought into contact with the pressing roller and the tip of the intake valve. 2. The valve operating system for a four-cycle engine according to claim 1, wherein the position where the pressing roller contacts the slipper surface is the force point, and the position where the tip of the intake valve contacts the slipper surface is the point of action. 9. An actuator of the fulcrum member and a drive portion thereof are arranged between a timing chain that rotationally drives the intake cam shaft and a cylinder adjacent thereto, and a fulcrum member near the engine end portion on the opposite side. The valve operating system for a four-cycle engine according to claim 1, further comprising: a rotation detecting means for the intake camshaft. 10. The valve operating system for a four-cycle engine according to claim 1, further comprising an urging means for lightly pressing the pressing roller against the intake cam. 11. The valve operating system for a four-cycle engine according to claim 8, wherein the arc radius of the slipper surface of the rocker arm is gradually changed so as to increase slightly from the action point side toward the force point side. 12. The intake valve and two intake ports opened / closed by the intake valve are provided for each cylinder, and each intake valve is lifted by a separate rocker arm, and the force points of these two rocker arms are set to the intake camshaft. Of the two intake cams and the corresponding pressure roller can press only the force point of one rocker arm, and the other intake cam and the corresponding pressure roller are The intake cam capable of pressing the rocker arms at the same time and pressing only one of the rocker arms is a low-medium speed intake cam, and the intake cam capable of pressing both rocker arms is a high-speed intake cam. A valve train for a four-cycle engine as described. 13. The valve opening angle of the low-medium speed intake cam is set smaller than the valve opening angle of the high-speed intake cam.
2. A valve train for a 4-cycle engine according to item 2. 14. The passage area of an intake port that is opened in both the low and medium speed range and the high speed range of the two intake ports is set to be smaller than the passage area of the intake port that is opened only in the high speed range. A valve train for a four-cycle engine as described. 15. The four-cycle according to claim 12, wherein one of the two intake ports is formed substantially parallel to the cylinder axis and the other intake port is formed substantially perpendicular to the cylinder axis. Engine valve system. 16. The valve operating system for a four-cycle engine according to claim 15, wherein the intake port that opens in the low to medium speed range is formed substantially parallel to the cylinder axis.