JPH0510162A - Cycle suspension reciprocating type internal combustion engine - Google Patents

Abstract

PURPOSE:To provide a cycle suspension reciprocating type internal combustion engine that is less in intake air resistance in a low load driving state and so good in fuel consumption. CONSTITUTION:A cam side intake rocker arm 20, a valve side intake rocker arm 21 and a timing gear 51 are fitted in a rocker arm shaft 24 (the exhaust side is also the same structure), shift pins 38, 39 are fitted in these rocker arms 20 and 21 free of slide motion, and an intake cam is rotated at a rotational speed of 1/2 of a crankshaft and the timing gear 51 at a rotational speed of 1/4, respectively. In a normal load state, a solenoid 72 is made into a state of nonoperation, the timing gear is separated from the rocker arm 21, the shift pin 38 is engaged with the rocker arm, and both these rocker arms are joined together, thus four-cycle driving takes place. In a low load state, the solenoid is operated and the timing gear is made to come nearer to the rocker arm 21, and per four-rotation in the crankshaft, one time releases coupling of both these rocker arms with a timing cam 53 of the timing gear, resting an intake valve, and another one time couples these rocker arms with a cam groove 55 of the timing gear, thereby operating the intake valve.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reciprocating internal combustion engine capable of intermittently and periodically stopping the opening and closing of intake and exhaust valves in accordance with the load applied to the internal combustion engine and the operating conditions to output appropriate power. It is about institutions.

[0002]

2. Description of the Related Art In a state in which a reciprocating four-cycle internal combustion engine is operating at a low load, one is generated every four revolutions of the crankshaft
The applicant filed an application for an internal combustion engine that can prevent an increase in intake resistance and a deterioration in combustion state by performing intake and exhaust only once and stopping intake and exhaust in other cycles (Japanese Patent Application No. See 412615). In the embodiment of the invention filed by the applicant of the present invention, valve cams are formed by arranging two cam ridges having 180 ° different phases in the axial direction, and the cam ridges of the valve cams are respectively contacted and rocked. One of the two rocker arms is slidably fitted with a locking pin that can be releasably engaged with the other rocker arm, and the tip of this one rocker arm is attached to the rear of the mushroom-shaped intake / exhaust valve. The valve cam is rotated at a rotational speed of 1/4 of the crankshaft during operation, and the rocker arms are disconnected in a low load state and the crankshaft rotates four times. Every time (that is, every eight strokes), the intake / exhaust valve is opened to output a small amount of power, and in a high load state, the rocker arms are connected to each other, and the crankshaft makes two revolutions (that is, every four strokes). ) Once to open the intake / exhaust valve It was supposed to output the motive power.

[0003]

[Problems to be Solved] In the above-mentioned internal combustion engine, since the valve cam is decelerated to a rotational speed of 1/4 of the crankshaft, the sprocket or gear for this deceleration becomes large in diameter and the deceleration mechanism becomes large in size. , Or chien 2
In the case where the gears are stepped or the gears are engaged in two stages, the structure is complicated and the cost and weight are inevitably increased. Furthermore, the width of the cam lobe of the valve cam becomes narrower and the cam lobe becomes an acute angle shape, so the surface pressure with the rocker arm slipper increases, and in order to cope with this,
It is necessary to use a material having excellent wear resistance for the sliding contact portion between the cam mountain and the rocker arm slipper.

[0004]

SUMMARY OF THE INVENTION The present invention relates to an improvement of a cycle-stop reciprocating internal combustion engine which overcomes the above-mentioned problems, and relates to a valve cam that rotates at half the rotational speed of a crankshaft, A slipper-side rocker arm that abuts on the valve cam and swings around a rocker arm shaft parallel to the cam shaft of the valve cam,
A valve pushing side rocker arm that abuts on an intake / exhaust valve and swings around the rocker arm shaft, a coupling means for detachably coupling the slipper side rocker arm and the valve pushing side rocker arm, and the valve operating cam. Timing gear that rotates at half the rotation speed of the timing gear, and the slipper side rocker arm and the valve pusher that are integrally provided on the end surface of the timing gear and that are rotated once within a predetermined rotation angle range each time the timing gear makes one rotation. A timing cam for releasing the coupling of the side rocker arm, and a cycle switching means for moving the timing gear along a rotational axis direction between a position where the timing cam can operate and a position where the timing cam cannot operate with respect to the coupling means. It is characterized by having and.

Since the present invention is configured as described above, when a high load condition or high output is required,
The timing gear moves to a position where the timing cam cannot operate with respect to the coupling means by the cycle switching means, and the slipper side rocker arm and the valve pushing side rocker arm are mutually coupled by the coupling means, 1 intake / exhaust valve every 2 crankshaft revolutions
It is opened once and set to a normal 4-cycle operating state, and thus a large amount of power can be output. Further, in the present invention, when a low load condition or a low output is sufficient, the cycle switching means moves the timing gear to a position where the timing cam can operate with respect to the coupling means, and the crankshaft rotates four times. The slipper-side rocker arm swings twice each time, but when swinging once, the slipper-side rocker arm and the valve push-side rocker arm are swung once within the predetermined rotation angle range by the timing cam. Is released, the rocker arm on the valve pushing side swings once for every two swings of the rocker arm on the slipper side. As a result, the intake / exhaust valve is rotated every four rotations of the crankshaft. Is opened only once and is set to an 8-cycle operating state, and a small amount of power can be output.

As described above, in the present invention, in the operating state in which the intake / exhaust valve is opened once every two revolutions of the crankshaft, the normal four strokes of intake, compression, combustion and exhaust are not interrupted midway. , Special operation that can output relatively large power under the same intake resistance and combustion condition as a normal reciprocating 4-cycle internal combustion engine, and that the intake and exhaust valves open once every four revolutions of the crankshaft. In this state, it is possible to operate in a state where combustion efficiency is improved by increasing intake / exhaust resistance due to 4-cycle throttle operation and increasing intake air amount per explosion, so there is no deterioration in combustion state per crank revolution. It is possible to reduce the average intake / exhaust amount of the engine and to reduce the engine output. Therefore, it is possible to always properly adjust the engine output with good fuel efficiency over a wide operating range from a low load operating state to a high load operating state. so That. Further, in the present invention, since the valve operating cam is rotated at half the rotational speed of the crankshaft as in a normal internal combustion engine, it is possible to avoid an increase in the size of the speed reducing mechanism of the valve operating system, a complication of the structure, and an increase in weight. Can
Furthermore, instead of making the timing cam of the valve cam a sharp-angled shape, the valve cam could be formed in the same smooth shape as the timing cam of an internal combustion engine, increasing the surface pressure between the timing cam and rocker arm slipper. It is possible to avoid it, without using special wear-resistant material for the sliding contact between the timing cam and rocker arm slipper.
These early wears can be avoided and durability can be improved.

[0007]

EXAMPLE An example of the present invention shown in the drawings will be described below. Reference numeral 1 denotes a reciprocating single-cylinder internal combustion engine mounted on a motorcycle (not shown). A crankshaft (not shown) is rotatably supported below the reciprocating single-cylinder internal combustion engine 1 and slidably fitted to a cylinder block 2. The mounted piston 5 is connected to the crankshaft via a connecting rod (not shown).
The crankshaft is driven to rotate by the reciprocating motion of the. Further, the cylinder head 3 is provided with one intake passage 6 and one exhaust passage 7, and the intake passage 6 is connected to an intake pipe (not shown) having a carburetor (not shown), and the exhaust passage 7 is provided. Is connected to an exhaust pipe (not shown). Further cylinder block 2,
An intake passage 6 and an exhaust passage 7 are opened in a combustion chamber 8 formed by a cylinder head 3 and a piston 5, and a mushroom-shaped intake valve 11 and a mushroom-shaped exhaust valve capable of opening and closing the intake port 9 and the exhaust port 10 freely. A mushroom-shaped intake valve 11 and a cylinder head 3 are provided with a valve spring 13 for urging the intake port 9 so that the intake port 9 is always closed by the mushroom-shaped intake valve 11 and the mushroom-shaped exhaust. A valve spring 14 is interposed between the valve 12 and the cylinder head 3 to urge the exhaust port 10 with the mushroom-shaped exhaust valve 12 so as to always close the exhaust port 10.

Further, a camshaft 16 is positioned above the intermediate between the mushroom-shaped intake valve 11 and the mushroom-shaped exhaust valve 12 and is rotatably supported between the cylinder block 2 and the cylinder head 3 via a bearing 15. The camshaft 16 is integrally formed with an intake cam 17 and an exhaust cam 18, and the camshaft 16 is integrally fitted with a driven sprocket 19.The driven sprocket 19 and a cam and a drive sprocket (not shown) are used to cam the crankshaft. The shaft 16 is connected, and the camshaft 16 is 1 / crank of the crankshaft.
It is designed to be rotationally driven at a rotational speed of 2. Moreover, the slipper side intake rocker arm 20 and the valve pushing side intake rocker arm 21 located above the mushroom-shaped intake valve 11 are swingably fitted to the rocker arm shaft 24 supported by the cylinder head 3, and A slipper side exhaust rocker arm 22 and a valve pushing side exhaust rocker arm 23, which are located above the mushroom-shaped exhaust valve 12, are swingably fitted to a rocker arm shaft 25 supported by the cylinder head 3. The rocker arm 20 and the slipper side exhaust rocker arm 22 are provided with slippers 26 and 27 that slidably contact the intake cam 17 and the exhaust cam 18, respectively, and the tips of the valve push side intake rocker arm 21 and the valve push side exhaust rocker arm 23 are mushrooms. Is in contact with the top ends of the intake valve 11 and the mushroom-shaped exhaust valve 12,
When the valve pushing side intake rocker arm 21 and the valve pushing side exhaust rocker arm 23 swing up and down, the mushroom-shaped intake valve 11 and the mushroom-shaped exhaust valve 12 are opened and closed.

The rocker arms 20, 21, 22, 23 are
As shown in FIGS. 1 and 12, spring receiving members 30, 31, 32, and 33 are formed, respectively, and compression coil springs are provided between the spring receiving members 30 and 31 and between the spring receiving members 32 and 33, respectively.
34, 35 are interposed, and this compression coil spring 3
Rocker arm on the slipper side 2 by the spring force of 4, 35
The slippers 26 and 27 of 0 and 22 are pressed against the intake cam 17 and the exhaust cam 18, and the tips of the rocker arms 21 and 23 on the valve pushing side are pressed against the top ends of the mushroom-shaped intake valve 11 and the mushroom-shaped exhaust valve 12. It has become. Further, as shown in FIGS. 4 and 6 to 8, pin holes 36 and 37 are formed in the slipper side intake rocker arm 20 and the valve pushing side intake rocker arm 21 in parallel with the rocker arm shaft 24, respectively. Shift pins 38, 39 are slidably fitted in the pin holes 36, 37, and a compression coil spring is provided between the shift pin 38 and the spring receiver 40 locked in the pin hole 36 of the slipper side intake rocker arm 20.
41 is interposed, and a spherical cam follower 42 is fitted to the outer end of the shift pin 39 of the valve push side intake rocker arm 21 to form a coupling means. Furthermore, the slipper side exhaust rocker arm 20 and the valve push side intake rocker arm 21 have an axial position opposite to that of the slipper side exhaust rocker arm.
22 and the valve push side exhaust rocker arm 23 constitute a coupling means. That is, pin holes 43 and 44 are formed in the slipper side exhaust rocker arm 22 and the valve pushing side exhaust rocker arm 23 in parallel with the rocker arm shaft 25, and the shift pins 45 and 46 are slidable in the pin holes 43 and 44. The compression coil spring 48 is interposed between the spring receiver 47 and the shift pin 46 which are engaged with the pin hole 44 of the valve push side exhaust rocker arm 23, and the outer end of the shift pin 45 of the slipper side exhaust rocker arm 22. A spherical cam follower 49 is fitted on.

A drive gear 50 is integrally fitted to the camshaft 16 on the opposite side of the driven sprocket 19 with the intake cam 17 and the exhaust cam 18 interposed therebetween, and the rocker arm shafts 24 and 25 mesh with the drive gear 50. Timing gear 51,
52 is slidably and rotatably fitted in the axial direction, and the timing gears 51 and 52 are half the rotational speed of the drive gear 50 and the camshaft 16 and one-fourth of the crankshaft (not shown). It is designed to be rotationally driven at a rotational speed. Further, the timing gears 51 and 52 have intake timing cams 5 on the side adjacent to the rocker arms 21 and 22.
3. An exhaust side timing cam 54 and cam grooves 55 and 56 are formed, and circumferential grooves 57 and 58 are formed on the opposite side. Note that the length between both ends of the intake side timing cam 53 and the exhaust side timing cam 54 in the circumferential direction is 100 at the center angle as shown in FIG.
The lift is linearly reduced from the ends of the intake side timing cam 53 and the exhaust side timing cam 54 to the cam grooves 55 and 56 as shown by the lowermost broken line in FIG. .

Furthermore, as shown in FIG. 9, a swing shaft 59 is screwed through the head cover 4 in parallel with the line connecting the center lines of the rocker arm shafts 24 and 25, and the swing shaft 59 is attached to the swing shaft 59. Intake side shift fork 60, exhaust side shift fork
61 is swingably fitted, the gear engaging claws 62, 63 of the shift forks 60, 61 are engaged with the circumferential grooves 57, 58 of the timing gears 51, 52, and the shift forks 60, 61
The push rod engaging claws 64, 65 of the push rods 66, 67
Are engaged with the circumferential grooves 68, 69 of the. Moreover, the intake-side push rod 66 and the exhaust-side push rod 67 are slidably fitted to the head cover 4, and two push grooves 66a, 70b, 71a, 71b are formed in the push rod 66, 67, respectively. .

A solenoid 72 is integrally mounted on the head cover 4, and a buffer compression coil spring 74 is provided at the tip of the movable piece 73 of the solenoid 72, the intake side push rod 66, and the exhaust side push rod 67, respectively. A return compression coil spring 75 is provided on the opposite side. Further, the intake-side trigger cam 78 and the exhaust-side trigger cam 79 are integrally mounted on the camshaft 16 and positioned above the intake cam 17 and the exhaust cam 18 in a relative positional relationship as shown in FIG. The intake side trigger plate 80 and the exhaust side trigger plate 81 are swingably supported by a support pin 86 integrally fitted to the head cover 4, and the cam ridges of the intake cam 17 and the exhaust cam 18 are slippers 26, In the state of contacting each of the slippers 27,
Intake side trigger cam 78, exhaust side trigger cam 79 Intake side trigger plate 80, exhaust side trigger plate on the cam bottom
The cam follower portions 82 and 83 of 81 come into contact with each other, and the locking portion 84,
85 is intake side push rod 66, exhaust side push rod 67
Even if the movable piece 73 moves due to the solenoid 72 being operated or released to engage with any of the two locking grooves 70a, 70b, 71a, 71b of the above, the intake side push rod
66, the exhaust side push rod 67 is forcibly stopped at that position. Furthermore, intake cam 17, exhaust cam
The timing at which the lift of the 18 cam ridges is switched from 0 to + and from + to 0, and the engaging portions 84 and 85 of the intake side trigger plate 80 and the exhaust side trigger plate 81 have the engaging grooves 70a and 70b,
71a, 71b is disengaged, and the locking grooves 70a, 70b, 71a, 71
It is configured to coincide with the timing of engaging with b.

Since the illustrated embodiment is constructed as described above, the solenoid 72 does not operate under normal load conditions, and as shown in FIGS.
The movable piece 73, the intake side push rod 66, and the exhaust side push rod 67 remain retracted, and the timing gear 51,
52 is held at a position apart from the spherical cam followers 42, 49 of the shift pins 39, 45. And shift pins 38, 3
Even if 9, 45 and 46 are pushed toward the intake side timing cam 53 and the exhaust side timing cam 54 by the spring force of the compression coil springs 41 and 48, the valve pushing side intake rocker arm 21,
By the stopper rings 76 and 77 fitted in the pin holes 37 and 43 of the slipper side exhaust rocker arm 22, the shift pins 39 and 45 are further moved from the state shown in FIG. 4 to the intake side timing cam 53 and the exhaust side timing cam 54. It does not project toward.

Further, as the intake cam 17, the exhaust cam 18, the intake-side trigger cam 78, and the exhaust-side trigger cam 79 rotate at a rotational speed half the crankshaft rotational speed, the intake side of the timing gears 51, 52 Timing cam 53 and exhaust side timing cam 54 are 1/4 of crankshaft rotation speed
However, as shown in FIG. 4, when the solenoid 72 is not operating, the timing gear is rotated.
Since 51 and 52 are separated from the valve push side intake rocker arm 21 and the slipper side exhaust rocker arm 22, the spherical cam followers 42 and 49 of the shift pins 39 and 45 each take one intake side timing every four rotations of the crankshaft. Even if the cam 53 and the exhaust side timing cam 54 face each other, the spherical cam followers 42 and 49 do not come into contact with the intake side timing cam 53 and the exhaust side timing cam 54 and are pushed in.

As described above, in the non-operating state of the Sonorade 72, the shift pins 38 and 46 are arranged so that the valve push side intake rocker arm 2
1, pin holes 37, 43 of the exhaust rocker arm 22 on the slipper side
The intake rocker arm 20 on the slipper side and the intake rocker arm 21 on the valve push side are integrally connected, and the exhaust rocker arm 22 on the slipper side is attached.
And the valve push side exhaust rocker arm 23 are integrally connected,
The crankshaft (not shown) makes two revolutions, that is, the camshaft 16 makes one revolution, and the slipper-side intake rocker arm 20 and the slipper-side exhaust rocker arm 22 become intake cams.
17, each time the exhaust cam 18 swings once, the valve push side intake rocker arm 21 and the valve push side exhaust rocker arm 23 also swing once, and the mushroom-shaped intake valve 11 and the mushroom-shaped exhaust valve 12 once. It is opened and normal four-cycle operation is performed.

Next, a transitional state in which the solenoid 72 operates in the low load state and the normal 4-cycle operation is switched to the 8-cycle operation in which the cycle is stopped will be described.
First, when the solenoid 72 operates, for example, at timing 1 in FIG. 13, the cam follower portion 82 of the intake side trigger plate 80 and the cam follower portion 83 of the exhaust side trigger plate 81 as shown in FIG. Neither of them completely rides on the cam ridges of the intake side trigger cam 78 and the exhaust side trigger cam 79, and the engagement parts 84 and 85 of the intake side trigger plate 80 and the exhaust side trigger plate 81 are the intake side push rod 6
6, because the engaging pieces 70a, 71b of the exhaust side push rod 67 are engaged, even if the movable piece 73 moves toward the stopper rings 76, 77 by the operation of the solenoid 72, the intake side push rod 66, The exhaust side push rod 67 has locking grooves 70a, 71
It cannot be moved because it is locked by the locking portions 84 and 85 that engage with a.

Then, when the timing 2 in FIG. 13 is reached, FIG.
As shown in the figure, in the exhaust system, the cam follower part 83 of the exhaust side trigger plate 81 completely rides on the cam mountain of the exhaust side trigger cam 79, and the locking part 85 of the exhaust side trigger plate 81 is attached to the exhaust side push rod. It comes off from the engaging groove 71a of 67,
The exhaust side push rod 67 can move toward the valve push side intake rocker arm 21 by the spring force of the buffer compression coil spring 74 and stop there, but the spherical cam follower 49 of the shift pin 45 has a cam groove of the timing gear 52. 56
Since the spherical cam follower 49 is not pushed by the exhaust side timing cam 54, the shift pin 46 does not move into the pin hole 43 of the slipper side exhaust rocker arm 22.
The exhaust rocker arm 22 on the slipper side and the exhaust rocker arm 23 on the valve pushing side are integrally connected, and the mushroom-shaped exhaust valve 12 starts opening by the exhaust cam 18.

In the intake system, however, at the timing 2 in FIG. 13, the cam follower portion 82 of the intake side trigger plate 80 is moved to the intake side trigger cam 78 as shown in FIG.
6, the engaging portion 84 of the intake side trigger plate 80 is engaged with the engaging groove 70a of the intake side push rod 66 as shown in FIG. The rod 66 is locked by the locking portion 84 that engages with the locking groove 70a and is kept in a non-movable state, and then at timing 3, the exhaust valve 12 is fully opened. Further, at the timing 4 of FIG. 13, the intake side timing cam 53 of the timing gear 51 faces the spherical cam follower 42 of the shift pin 39, and as shown in FIG. 16, the cam follower portion 82 of the intake side trigger plate 80. Rides on the cam peak of the intake side trigger cam 78, the locking portion 84 of the intake side trigger plate 80 disengages from the locking groove 70a of the intake side push rod 66, and the intake side push rod 66 is a spring of the buffer compression coil spring 74. The force attempts to move toward the timing gear 52, but at timing 4, the slipper 26 of the intake rocker arm 20 on the slipper side is caught by the cam mountain of the intake cam 17.
Is pushed up, and a frictional force larger than the spring force of the buffer compression coil spring 74 begins to be generated on the outer peripheral surface of the shift pin 39 and the pin hole 37 of the valve push side intake rocker arm 21, and the intake side push rod 66, the timing gear. 51 、 Shift pin
39 and 38 remain stationary, the shift pin 39 is not pushed deeply into the pin hole 37, the shift pin 38 engages with the pin hole 37, and the slipper side intake rocker arm 20 and the valve pushing side intake rocker arm 21 are integrally combined. Then, the mushroom-shaped intake valve 11 starts opening by the intake cam 17.

Further, at the timing 6 in FIG. 13, in the exhaust system, the cam follower portion of the exhaust side trigger plate 81 is
83 goes down from the cam mountain of the exhaust side trigger cam 79, and the locking part 85 of the exhaust side trigger plate 81 becomes the exhaust side push rod 67.
Since the timing gear 52 is engaged with the locking groove 71b of the timing gear 52 and cannot move in the axial direction, the spherical cam follower 49 of the shift pin 45, which is in contact with the cam groove 56 of the timing gear 52 at timing 6, does not move. In response to the increase in the lift of the exhaust side timing cam 54 as the 52 rotates,
It begins to be pushed into 43. Then, after the timing 10 in FIG. 13 is reached, the lift amount of the exhaust side timing cam 54 becomes maximum, and as shown in FIG. 7, the exhaust side timing cam 54 is lifted.
When the spherical cam follower 49 is pushed deeply into the pin hole 43 by the 54 and the abutting surfaces of the shift pins 45 and 46 match the adjacent surfaces of the slipper side exhaust rocker arm 22 and the valve pushing side exhaust rocker arm 23, the slipper side exhaust rocker. Arm 22
Even if the slipper 27 of the slipper side exhaust rocker arm 22 is lifted up by the exhaust cam 18, the valve push side exhaust rocker arm 23 is lifted by the exhaust cam 18.
23 does not swing, and the mushroom-shaped exhaust valve 12 does not open and pauses from timing 10 to timing 14.

When timing 8 in FIG. 13 is reached again,
In the intake system, at the same time as the mushroom-shaped intake valve 11 is closed, as shown in FIG. 19, the cam follower part 82 of the intake side trigger plate 80 begins to descend from the cam mountain of the intake side trigger cam 78, and the intake side trigger is triggered. The locking portion 84 of the plate 80 is engaged with 70a, so that the intake side push rod 66 and the timing gear 51 cannot approach the valve push side intake rocker arm 21 side. Then, when timing 12 in FIG. 13 is reached, as shown in FIG. 16, the cam follower portion 82 of the intake side trigger plate 80 rides on the cam mountain of the intake side trigger cam 78 again, and the engagement of the intake side trigger plate 80 is resumed. The stopper 84 is disengaged from the locking groove 70a of the intake side push rod 66, and the cam groove 55 of the timing gear 51 faces the spherical cam follower 42 of the shift pin 39.
Return compression coil spring even if protruding towards
The spring force of 75 causes the intake side push rod 66 and the timing gear 51 to move toward the valve push side intake rocker arm 21, so that the engagement groove 70b of the intake side push rod 66 engages with the intake side trigger plate 80. It can move to a position adjacent to the portion 84, the shift pin 38 engages with the pin hole 37, and the slipper side intake rocker arm 20 and the valve push side intake rocker arm 21.
Are integrally connected, and the mushroom-shaped intake valve 11 starts opening the intake cam 17.

Therefore, in the intake system, when the timing 16 of FIG. 13 is reached, the cam follower portion 82 of the intake side trigger plate 80 descends again from the cam mountain of the intake side trigger cam 78, and the engagement of the intake side trigger plate 80 is reduced. Since the timing gear 51 is fixed so as not to move in the axial direction by engaging with the locking groove 70b of the stopper 84, the intake side timing cam 53 is fixed to the spherical cam follower 42 of the shift pin 39 as the timing gear 51 rotates. As approaching, the spherical cam follower 42 of the shift pin 39 is pushed by the intake side timing cam 53, the timing 20 of FIG. 13 is reached, and as shown in FIG. 8, the abutting surfaces of the shift pins 38 and 39 are on the slipper side. If the contact surfaces of the intake rocker arm 20 and the valve push side intake rocker arm 21 match, the slipper side intake rocker arm
20 and the valve push side intake rocker arm 21 is released,
Even if the slipper 26 of the abutment surface of the intake rocker arm 20 on the slipper side is pushed up by the intake cam 17, the intake rocker arm 21 on the valve pushing side does not swing, the mushroom-shaped intake valve 11 does not open, and the timing starts from timing 20. Pause for 24 hours.

After that, the timing gears 51 and 52 both approach the valve push side intake rocker arm 21 and the slipper side exhaust rocker arm 22, and the intake side trigger plate 80,
The engaging portions 84 and 85 of the exhaust side trigger plate 81 are the engaging side push rod 66, the engaging groove 70b of the exhaust side push rod 67,
Since the intake side push rod 66 and the exhaust side push rod 67 are prevented from moving in the axial direction by engaging with 71b, when the intake side timing cam 53 and the exhaust side timing cam 54 face the spherical cam followers 42, 49. After the mushroom-shaped intake valve 11 and the mushroom-shaped exhaust valve 12 are stopped and the crankshaft further rotates two times respectively, the mushroom-shaped intake is performed with the cam grooves 55 and 56 facing the spherical cam followers 42 and 49. The valve 11 and the mushroom-shaped exhaust valve 12 are opened. In this way, after the crankshaft makes two revolutions and the intake, compression, combustion, and exhaust strokes are performed, the intake, compression, combustion, and exhaust strokes are stopped during the next two crankshaft revolutions, and the crankshaft Every four rotations, the normal four strokes and the rest four strokes are repeated alternately.

Therefore, the state in which the intake, compression, combustion, and exhaust strokes are performed and the state in which they are stopped alternate between the timing gears 51 and 52 making one revolution, that is, the crankshaft making four revolutions. Since the number of intakes is halved by repeating each time, the engine output can be halved without reducing the intake amount when the fungiform intake valve 11 is opened by the throttle of a throttle valve (not shown).

Therefore, even in a low load operation state, it is possible to avoid an increase in intake loss and a deterioration in combustion state due to the throttle of the throttle valve, so that the fuel consumption can be improved.

Further, since the intake cam 17 and the exhaust cam 18 can be made into the same shape as the cam of a normal four-cycle internal combustion engine without making the shape of the acute angle, the intake cam 17, the exhaust cam 18, and the slipper 26 These heavy wears can be avoided without the use of special wear-resistant materials for 27 and 27.

Further, when the solenoid 72 operates, the movement of the movable piece 73 of the solenoid 72 is transmitted to the push rods 66 and 67 via the buffer compression coil spring 74, but the buffer compression coil spring 74 elastically moves. The mushroom-shaped intake valve 11 and the mushroom-shaped exhaust valve are prevented from being compressed and deformed and the push rods 66 and 67 are not forcibly moved in the axial direction.
12 is opened and the timing gears 51, 52
When the cam grooves 55, 56 of the driven plates 80, 81 are in a state of being opposed to the spherical cam followers 42, 49, the engaging portions 84, 85 of the driven plates 80, 81 are disengaged from the engaging grooves 70, 71 of the push rods 66, 67 and are pushed. The rods 66 and 67 move, and in the next stroke, the locking portions 84 and 85 of the driven plates 80 and 81 engage with the locking grooves 70 and 71 of the push rods 66 and 67, so that the intake side timing cam 53 and the exhaust gas are discharged. The shift pins 39, 45 are pushed in by the side timing cam 54, the slipper side rocker arm 20 and the valve pushing side rocker arm 21, and the slipper side rocker arm 22 and the valve pushing side rocker arm 23 are released, and the mushroom-shaped intake valve 1
1. Since the mushroom-shaped exhaust valve 12 is inactive, the switching between the normal 4-cycle operating state and the 8-cycle operating state accompanied by cycle suspension is smoothly performed, and the push rods 66, 67 are also provided.
In addition, the timing gears 51 and 52, the shift pins 38 and 39, the pin holes 44, and the shift pin 45 are prevented from being damaged by an unreasonable force.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional front view showing an embodiment of a cycle-stop reciprocating internal combustion engine according to the present invention.

FIG. 2 is a vertical sectional side view thereof.

FIG. 3 is a partially longitudinal rear view of the head cover.

FIG. 4 is a vertical cross-sectional plan view of an essential part of the head cover when the solenoid does not operate and at timing 1 in FIG.

FIG. 5 is a vertical sectional side view showing a state where a solenoid operates.

6 is a vertical cross-sectional plan view of an essential part of the head cover when the solenoid operates and at timing 2 in FIG.

7 is a vertical cross-sectional plan view of essential parts of the head cover when the solenoid operates and at timing 10 in FIG.

8 is a vertical cross-sectional plan view of an essential part of the head cover when the solenoid operates and at timing 20 in FIG.

9 is a cross-sectional front view cut along the line IX-IX in FIG.

FIG. 10 is a front view of a timing cam.

11 is a vertical sectional side view cut along the line XI-XI in FIG. 10.

FIG. 12 is an exploded front view of a slipper-side rocker arm and a valve pushing-side rocker arm.

FIG. 13 is an explanatory diagram illustrating an operation of the intake and exhaust valves, a rest state, and an operation state of the timing cam.

14 is a cross-sectional front view of timings 1, 9, and 17 cut along the line XIV-XIV in FIG. 4.

15 is a cross-sectional front view similar to FIG. 14 at timings 2, 10, and 18. FIG.

16 is a cross-sectional front view similar to FIG. 14 at timings 4, 12, and 20.

17 is a cross-sectional front view similar to FIG. 14 at timings 5, 13, and 21. FIG.

18 is a cross-sectional front view similar to FIG. 14 at timings 6, 14, and 22. FIG.

FIG. 19 is a cross-sectional front view similar to FIG. 14 at timings 8, 16 and 24.

[Explanation of symbols]

1 ... Reciprocating single cylinder internal combustion engine, 2 ... Cylinder block, 3
… Cylinder head, 4… Head cover, 5… Piston,
6 ... Intake passage, 7 ... Exhaust passage, 8 ... Combustion chamber, 9 ... Intake port, 10 ... Exhaust port, 11 ... Fungiform intake valve, 12 ... Fungiform exhaust valve, 1
3, 14 ... Valve spring, 15 ... Bearing, 16 ... Cam shaft, 17 ... Intake cam, 18 ... Exhaust cam, 19 ... Driven sprocket, 20 ... Slipper side intake rocker arm,
21 ... Valve push side intake rocker arm, 22 ... Slipper side exhaust rocker arm, 23 ... Valve push side exhaust rocker arm,
24, 25 ... Rocker arm shaft, 26, 27 ... Slipper, 30, 31, 32, 33 ... Spring receiving member, 34, 35 ... Compression coil spring, 36, 37 ... Pin hole, 38, 39 ... Shift pin, 40
… Spring receiver, 41… Compression coil spring, 42… Spherical cam follower, 43, 44… Pin hole, 45, 46… Shift pin, 47
... Spring receiver, 48 ... Compression coil spring, 49 ... Spherical cam follower, 50 ... Drive gear, 51, 52 ... Timing gear, 53 ... Intake side timing cam, 54 ... Exhaust side timing cam, 55, 56 ... Cam groove, 57 , 58 ... Circumferential groove, 59 ... Swing shaft, 60 ... Intake side shift fork, 61 ... Exhaust side shift fork, 62, 63 ... Gear engaging claw, 64, 65 ... Push rod engaging claw, 66 ... Intake side Push rod, 67 ... Exhaust side push rod, 68, 69 ... Circumferential groove, 70, 71 ... Locking groove, 72 ... Solenoid, 73 ... Movable piece, 74 ... Buffer compression coil spring, 75 ... Return compression coil spring, 76 , 77 ... Stopper ring, 78 ... Intake side trigger cam, 79 ... Exhaust side trigger cam, 80 ... Intake side trigger plate, 81 ... Exhaust side trigger plate, 82,83 ... Cam follower part, 84,85
… Locking part, 86… Support pin.

Claims (2)

[Claims] 1. A slipper-side rocker that swings around a rocker arm shaft that is in contact with the valve cam and that is parallel to the camshaft of the valve cam and that rotates at a speed half that of the crankshaft. An arm, a valve pushing side rocker arm that abuts the intake / exhaust valve and swings around the rocker arm shaft, a coupling means that detachably couples the slipper side rocker arm and the valve pushing side rocker arm, and The timing gear that rotates at half the rotational speed of the valve cam, and the slipper-side rocker arm that is integrally provided on the end surface of the timing gear and that is rotated once within a predetermined rotation angle range each time the timing gear rotates once. And a timing cam for releasing the coupling of the rocker arm on the valve pushing side and the timing cam for the coupling means. A cycle reciprocating reciprocating internal combustion engine, comprising: cycle switching means for moving the timing gear along a rotational axis direction between a position in which the timing gear can move and a position in which the timing gear cannot operate. 2. An intake / exhaust valve is equipped with a switching timing control means which prepares for cycle switching during the valve opening period and performs cycle switching during the valve opening period of the intake / exhaust valve after completion of the cycle switching preparation. The cycle-stop reciprocating internal combustion engine according to claim 1, wherein: