JP3195880B2 - Valve train with stop mechanism for internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve operating mechanism for an internal combustion engine, and more particularly to a valve operating mechanism having a mechanism for stopping a desired one of a plurality of intake and exhaust valves at a predetermined time. is there.

[0002]

2. Description of the Related Art A valve train with a stop mechanism of this type is effective for reducing the fuel consumption of an internal combustion engine during actual use. The applicant has disclosed in Japanese Patent Application Laid-Open No. 63-16112 a piston guide 52 made of a light alloy or a synthetic resin formed separately from an inverted cup-shaped lifter 51 as shown in FIGS. A cylinder hole 53 formed in the piston guide 52 and assembled inside the lifter 51.
Has proposed a valve mechanism with a rest mechanism in which a substantially round rod-shaped piston 54 is inserted so as to be able to reciprocate. A stem end 55 of an intake / exhaust valve 56 is inserted into a stem hole 55 penetrated through the piston 54.
When the valve enters, the valve stroke is absorbed by the stem hole 55, and the intake / exhaust valve 56 is brought into a rest state. As a similar technique, there is a technique disclosed in Japanese Utility Model Application Laid-Open No. 61-134504.

According to the valve operating mechanism with a pause mechanism, a prior art is disclosed in Japanese Patent Application Laid-Open No. 61-8416, in which a cylinder hole is formed in the lifter itself and a piston is inserted into the cylinder hole. As compared with the example, the effect that the weight is reduced and the processing and the assembling are facilitated is obtained.

[0004]

However, the prior art valve train with a stop mechanism proposed by the present applicant also has a problem.
The following problems remained. Since the height of the stem hole 55, that is, the height of the piston 54 needs to be increased in order to absorb the valve stroke at rest, the dimension from the lower surface of the piston 54 to the upper surface of the end wall of the lifter 51 as shown in FIG. Increased, and it became bulky in the height direction and was restricted in space. The provision of the high piston 54 leads to an increase in the weight of the piston 54, the piston guide 52, and the lifter 51, which is disadvantageous in fuel efficiency and increases the inertial weight of the valve operating mechanism. There is a possibility that the followability of the valve train with respect to rotation may be reduced. Since there was no means for adjusting the valve clearance, the adjustment was very difficult. Therefore, as shown in FIG. 24, a structure is conceivable in which a shim 58 for adjusting the valve clearance is attached to the end wall of the lifter 51. However, doing so further worsens the above-described problem.

[0005] An object of the present invention is to solve the above-mentioned problems, to provide a valve train with a pause mechanism that can be formed compact in the height direction, can be reduced in weight, and can also adjust the valve clearance. It is in.

[0006]

SUMMARY OF THE INVENTION To achieve the above object, a valve train mechanism with a stop mechanism for an internal combustion engine according to the present invention is slidably inserted into a lifter guide hole of a cylinder head to perform a cam action of a cam. Equipped with an inverted cup-shaped lifter that transmits to the intake / exhaust valve, and a piston that reciprocates in the lifter in a direction substantially perpendicular to the axis of the intake / exhaust valve, and the stem end of the intake / exhaust valve can enter the piston. a first access holes provided such stem end through the entry into the first entrance hole is followed by an end wall of the lifter is provided entering possible second entrance hole, a piston thin plate shape
Formed and made of torsion coil spring or leaf spring short
The return spring biases the piston in one direction .

Also, the lifter guide hole of the cylinder head
Slidably inserted to transmit cam action to intake and exhaust valves
Inverted cup-shaped lifter and intake / exhaust valve inside the lifter
Piston reciprocating in a direction substantially perpendicular to the axis of
Equipped with a piston that allows the stem end of the intake / exhaust valve to enter the piston.
One entry hole is provided, and the end wall of the lifter is
A second entry hole through which the stem end that has passed can be entered subsequently,
The piston is formed in a thin plate shape, and the piston
The cylinder groove is recessed on one side of the
May be slidably inserted.

In addition, the lifter guide hole of the cylinder head
Slidably inserted to transmit cam action to intake and exhaust valves
Inverted cup-shaped lifter and intake / exhaust valve inside the lifter
Piston reciprocating in a direction substantially perpendicular to the axis of
Equipped with a piston that allows the stem end of the intake / exhaust valve to enter the piston.
One entry hole is provided, and the end wall of the lifter is
A second entry hole through which the stem end that has passed can be entered subsequently,
The piston is formed in a thin plate shape, a cylinder groove is recessed on one side of the substantially disk-shaped piston guide, the piston is slidably inserted into the cylinder groove, and the piston guide is press-fitted and fixed inside the lifter. A pressure chamber is formed between the piston and the piston guide in the groove, a piston guide communication hole for supplying engine oil to the pressure chamber is provided in the piston guide, and a lifter communication hole communicating with the piston guide communication hole is provided in the lifter. It is preferable to provide an oil flow passage communicating with the communication hole in the cylinder head.

A return spring mounting groove is recessed at the end of the cylinder groove in the piston guide, and a short return spring is fitted into the return spring mounting groove, and the return spring urges the piston in one direction. be able to. Here, examples of the short return spring include a torsion coil spring and a leaf spring. The torsion coil spring refers to a spring in which a spring wire is wound in a coil shape and both ends of the spring wire are stretched to exert elasticity in the torsion direction.

Next, in the lifter guide hole of the cylinder head,
Slidably inserted to transmit cam action to intake and exhaust valves
Inverted cup-shaped lifter and intake / exhaust valve inside the lifter
Piston reciprocating in a direction substantially perpendicular to the axis of
Equipped with a piston that allows the stem end of the intake / exhaust valve to enter the piston.
One entry hole is provided, and the end wall of the lifter is
A second entry hole through which the stem end that has passed can be entered subsequently,
A shim may be attached to the end wall of the lifter, and the shim may be provided with a third entry hole through which a stem end portion that has entered the second entry hole can subsequently enter.

Also, the lifter guide hole of the cylinder head
Slidably inserted to transmit cam action to intake and exhaust valves
Inverted cup-shaped lifter and intake / exhaust valve inside the lifter
Piston reciprocating in a direction substantially perpendicular to the axis of
Equipped with a piston that allows the stem end of the intake / exhaust valve to enter the piston.
One entry hole is provided, and the end wall of the lifter is
A second entry hole through which the stem end that has passed can be entered subsequently,
The cam may be provided with an entry groove in which the stem end portion that has entered the second entry hole can subsequently enter.

Further, the third entry hole and the entry groove may be combined, that is, the cam may be provided with an entry groove through which the stem end portion which has entered the third entry hole can subsequently enter.

In addition, an operating pressure chamber is formed between one end of the piston and the piston guide, and a stop pressure chamber is formed between the other end of the piston and the piston guide. An operation piston guide communication hole and a pause piston guide communication hole for supplying engine oil to the pressure chamber are provided in the piston guide, and an operation lifter communication hole communicating with the operation piston guide communication hole and the suspension piston guide communication hole, respectively. The lifter communication hole may be provided in the lifter, and the cylinder head may be provided with an operation oil flow path and a stop oil flow path that respectively communicate with the operation lifter communication hole and the stop lifter communication hole.

Further, the operating lifter communication hole and the resting lifter communication hole, and the working oil passage and the resting oil passage are provided so as to communicate with each other only when the base circle of the cam corresponds to the lifter. Is preferred.

Next, it is preferable to provide a detachment preventing means for stopping the return spring in the return spring mounting groove.

[0016]

According to the valve train with the stop mechanism of the internal combustion engine according to the present invention, at the time of stop, the stem end of the intake / exhaust valve has:
Since the valve enters the first entry hole provided in the piston inside the lifter and subsequently enters the second entry hole provided in the end wall of the lifter, the valve stroke is increased by these first and second entry holes. Absorbed. Therefore, compared to the conventional example in which the valve stroke is absorbed only by the stem hole of the piston, the height of the piston can be reduced by the thickness of the end wall of the lifter, and the valve train is made compact in the height direction. Can be formed. Also, the weight of the piston, lifter, etc. can be reduced by the amount that the height of the piston can be reduced, which is advantageous in fuel efficiency, and the inertia weight of the valve mechanism is reduced,
The followability of the valve train to the high-speed rotation of the internal combustion engine is also improved. In addition to the above action, the piston was formed into a thin plate shape
Therefore, the height can be reduced and the first
It can be easily formed. In addition, a short return spring
To bias the piston in one direction.
Suitable for minimizing height space
You.

Further , the piston is formed in a thin plate shape,
A cylinder groove is recessed on one side of the disc-shaped piston guide,
Insert the piston slidably into the cylinder groove.
If these piston guide, cylinder groove and piston
Can be easily processed.

Further, the piston is formed in a thin plate shape, and a cylinder groove is recessed on one surface of a substantially disc-shaped piston guide.
If the piston is slidably inserted into the cylinder groove, the piston guide, the cylinder groove, and the piston can be easily processed. A piston guide is press-fitted and fixed inside the lifter, a pressure chamber is formed between the piston and the piston guide, and a piston guide communication hole for supplying engine oil to the pressure chamber is provided in the piston guide and communicates with the piston guide communication hole. If the lifter communication hole is provided in the lifter and the oil flow path communicating with the lifter communication hole is provided in the cylinder head, the lifter and the piston guide are pressed against each other to seal the hydraulic pressure, thereby preventing a decrease in hydraulic pressure.

A return spring mounting groove is recessed at an end of the cylinder groove in the piston guide, and a short return spring is fitted into the return spring mounting groove, and the return spring attaches the piston in one direction. By energizing the return spring, the height of the return spring can be minimized, and this can be accommodated in the piston guide. Here, if a pair of return springs are disposed symmetrically on both sides of the piston and the piston is biased by both return springs, the piston can be biased smoothly without bias.

Next, if a shim is attached to the end wall of the lifter and a third entrance hole is provided in the shim, the stem end of the intake / exhaust valve can be closed only at the first and second entrance holes at the time of rest. Instead, the valve enters the third entrance hole of the shim, so that the first to third entrance holes absorb the valve stroke.
Therefore, even if the shim is mounted, the height of the piston may be further reduced by the thickness of the shim, so that there is no need to worry about the valve operating mechanism becoming bulky in the height direction, and it is possible to form the valve mechanism compact. The valve clearance can be easily adjusted by selectively mounting a shim having a desired thickness from among shims having various thicknesses.

If the cam is provided with an entry groove, the stem end of the intake / exhaust valve enters not only the first and second entry holes but also the entry groove of the cam at rest. The valve hole is absorbed by the entry hole and the entry groove. Therefore, since the height of the piston may be further reduced by the depth of the entry groove, there is no need to worry about the valve operating mechanism becoming bulky in the height direction, and the valve mechanism can be formed compact.

Further, if the third entry hole and the entry groove are combined, that is, if the shim is provided with the third entry hole and the cam is provided with the entry groove, the stem end portion of the intake / exhaust valve at the time of rest can be provided. Since it also enters the first to third entry holes and entry grooves, the valve stroke is absorbed by these entry holes and entry grooves. Therefore, the valve train can be formed most compact in the height direction.

An operating pressure chamber is formed between one end of the piston and the piston guide, and a resting pressure chamber is formed between the other end of the piston and the piston guide. An operation piston guide communication hole and a pause piston guide communication hole for supplying engine oil to the pressure chamber are provided in the piston guide, and an operation lifter communication hole communicating with the operation piston guide communication hole and the suspension piston guide communication hole, respectively. If a lifter communication hole is provided in the lifter, and an operation oil flow path and a stop oil flow path communicating with the operation lifter communication hole and the stop lifter communication hole are respectively provided in the cylinder head, the piston is operated by hydraulic pressure. Can be displaced at high speed in both directions, and switching from the idle state to the active state and switching from the active state to the idle state can be performed more smoothly and instantaneously. It can be carried out in. When a return spring is provided, the spring load can be reduced, so that the state can be switched even when the hydraulic pressure is low. In addition, even if the return spring malfunctions due to some kind of abnormality such as the entry of foreign matter, there is no fear that the switching of the state becomes impossible.

Further, an operating lifter communicating hole and a resting lifter communicating hole, and an operating oil passage and a resting oil passage are provided so as to communicate with each other only when the base circle of the cam corresponds to the lifter. In this case, the amount of engine oil leakage can be reduced.

Next, in the case where disengagement prevention means for stopping the return spring is provided in the return spring mounting groove, the return spring is fitted in the return spring mounting groove, and then the piston guide is fixed to the lifter. Until the end, the return spring does not come off the return spring mounting groove, so that the assemblability of the piston guide and the return spring can be improved.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a valve train with a stop mechanism for an internal combustion engine embodying the present invention will be described below with reference to the drawings.

First, FIGS. 1 to 6 show a valve operating mechanism with a stop mechanism according to the first embodiment. 1 and 2 show the entirety of the same valve mechanism. A lifter guide hole 2, a valve spring chamber 3 and a flow path 4
A pipe-shaped valve guide 5 is mounted on a boundary wall between the valve spring chamber 3 and the air passage 4. The stem 7 of the intake / exhaust valve 6 is slidably fitted into the valve guide 5, and the stem 7 extends into the lifter guide hole 2. A retainer 8 is attached to the upper end of the stem portion 7 slightly below the stem end portion 7a via a cotter 9. A suction and exhaust valve 6 is provided between the retainer 8 and the inner bottom of the valve spring chamber 3. A valve spring 10 for urging the valve upward is interposed.

An inverted cup-shaped lifter 11 having an upper end wall 12 and a peripheral wall 13 as shown in FIG. 4 is slidably inserted into the lifter guide hole 2. A circular second entry hole 14 into which the stem end 7a can enter is vertically provided through the center of the end wall 12. A lifter oil groove 15 is provided at the right end of the outer peripheral surface of the peripheral wall 13 in the drawing.
Further, a lifter communication hole 16 for communicating the lifter oil groove 15 with a later-described piston guide oil groove 25 is formed in the peripheral wall 13.

A disk-shaped shim 17 as shown in FIG. 3 is mounted on the upper surface of the end wall 12 so as to be dropped into a convex wall 12a provided upright on the peripheral edge thereof. At the center of the shim 17, a stem end portion 7a that has entered the second entry hole 14 is a circular third entry hole 1 that can be entered subsequently.
8 penetrates vertically. The upper surface of the shim 17 is in sliding contact with the cam 19, and the width of the cam 19 in the thickness direction in FIG. 1 is larger than the diameter of the third entry hole 18. You will not enter.

Inside the lifter 11, a substantially disk-shaped piston guide 2 made of an aluminum alloy as shown in FIG.
0 is press-fitted and fixed so as to contact the end wall 12.
A lost motion spring 21 is interposed between the lower surface of the piston guide 20 and the retainer 8, and urges the piston guide 20 upward without pushing the retainer 8 downward. Therefore, lost motion spring 2
1 is the valve spring 10 even when fully compressed
Has such a low spring constant that it does not compress.

On the upper surface of the piston guide 20, a shallow cylinder groove 2 extending in a direction orthogonal to the axial direction of the stem 7 is provided.
2, a pair of return spring mounting grooves 23 deeper than the cylinder groove 22 are formed on both sides of the left end of the cylinder groove 22 in the drawing. The cylinder groove 22 forms a cylinder hole together with the lower surface of the end wall 12. The center end of the piston guide 20 has a stem end 7
A vertical stem hole 24 that a is always inserted through is provided,
This stem hole 24 intersects the cylinder groove 22. A piston guide oil groove 25 communicating with the lifter communication hole 16 is formed at the right end of the piston guide 20 in the drawing, and a piston guide that communicates the piston guide oil groove 25 with a pressure chamber 32 described later. Communication hole 2
6 is provided through. Since the outer peripheral surface of the piston guide 20 is in pressure contact with the inner peripheral surface of the lifter 11 and the sealing property therebetween is high, a decrease in oil pressure in the piston guide oil groove 25 can be prevented.

A flat piston 30 as shown in FIG. 6 is inserted into the cylinder groove 22 so as to be slidable in the left-right direction. The left end face of the piston 30 in the drawing is formed in a plane arc shape, and the right end face in the drawing is formed in a flat rounded corner like the right end face of the piston guide 20. A pair of return springs using a short torsion coil spring formed by winding a spring wire in a coil shape and extending both ends of the spring wire in a V-shape so as to intersect each other when viewed from above. 31 is fitted, one end of each return spring 31 abuts the left end surface of the piston 30 and the other end abuts the left end surface of the return spring mounting groove 23 in the drawing to urge the piston 30 rightward. are doing. Since the return spring 31 can be formed short, it is suitable for minimizing the space in the height direction.

On the other hand, a pressure chamber 32 is provided between the right end face of the piston 30 and the right end face of the piston guide 20, and the lifter oil groove 15 → the lifter communication hole 16 → the piston guide oil groove 25 → the piston guide communication hole 26. → When the engine oil is pumped through the path of the pressure chamber 32, the piston 30 is displaced leftward against the repulsive force of the return spring 31, and the engine oil is discharged from the pressure chamber 32 through the reverse path. When this occurs, the piston 30 is displaced rightward by the repulsive force of the return spring 31.

The right end of the piston 30 has a stem end 7a
Is penetrated in a vertical direction. When the piston 30 is displaced leftward as described above, the first entry hole 33 is
4, coincides with the second entry hole 14 and the third entry hole 18, and the stem end 7a enters these. When the piston 30 is displaced to the right as described above, the first entry hole 33 is different from the stem hole 24, the second entry hole 14 and the third entry hole 18, and the stem end 7a is The lower surface 30 is brought into contact with the lower surface.

The cylinder head 1 is provided with an oil passage 35 opening to the lifter oil groove 15, and the engine oil is supplied to the oil passage 35 by a pump 36 through an oil supply pipe 38 having a switching valve 37 in the middle. It is supposed to be. The engine oil is discharged from the pressure chamber 32 to the oil pan 40 via the switching valve 37 and the drain pipe 39. The switching valve 37 is controlled by a computer (not shown).

The valve train with a pause mechanism according to this embodiment operates as follows. First, when the internal combustion engine is under a high load, FIG.
As shown in the figure, the switching valve 37 is switched so that the pressure chamber 32 and the oil pan 40 communicate with each other according to a command from the computer. Therefore, since no pressure is applied to the pressure chamber 32, the piston 30 is displaced rightward by the urging force of the return spring 31. When the cam 19 rotates in this state, the stem end 7a in contact with the lower surface of the piston 30 is pushed downward via the lifter 11, the piston guide 20, and the piston 30, and the intake / exhaust valve 6 is opened.
The intake / exhaust valve 6 is closed by the urging force of the valve spring 10.

Next, when the intake / exhaust valve 6 is stopped during a low load of the internal combustion engine, as shown in FIG. 2, the switching valve 37 is switched so that the pressure chamber 32 and the pump 36 communicate with each other according to a command from a computer. Can be Therefore, the engine oil is pressure-fed to the pressure chamber 32 in the above-mentioned path and pressure is applied, so that the piston 30 is displaced leftward. Then, the stem end portion 7a comes off the lower surface of the piston 30, enters the first entry hole 33, subsequently enters the second entry hole 14, and subsequently enters the third entry hole 18. When the cam 19 rotates in this state, the lifter 11, the piston guide 20
And the piston 30 is pushed downward, but the stem end 7a
Are the first, second and third entry holes 33, 14,
Enter 18. Also, lost motion spring 2
1 merely repeats its own compression and return, and does not compress the valve spring 10 as described above. Therefore, the cam action of the cam 19 is not transmitted to the intake / exhaust valve 6, the valve stroke is absorbed, and the intake / exhaust valve 6 is brought into a rest state.

According to the valve operating mechanism with a rest mechanism of the present embodiment as described above, the end wall 12 of the lifter 11 and the shim 17 are different from those of the prior art in which the valve stroke is absorbed only by the stem hole of the piston. Piston 3 for both thicknesses
The height of the valve mechanism can be made compact in the height direction by reducing the height from the lower surface of the piston 30 to the upper surface of the end wall 12. Also, the piston 30
Since the weight of the piston 30, the piston guide 20, the lifter 11, and the like can be reduced by an amount corresponding to a reduction in the height of the engine, the fuel efficiency is improved, and the inertial weight of the valve operating mechanism is reduced. The followability of the valve mechanism is also improved.

Further, the valve clearance can be easily adjusted by selectively mounting the shim 17 having a desired thickness from the shims having various thicknesses on the end wall 12.

Next, FIG. 7 shows a valve operating mechanism with a pause mechanism according to the second embodiment, in which the cam 19 (as viewed from the side at 90 degrees with respect to FIG. 1) enters the third entrance hole 18. The second embodiment differs from the first embodiment only in that an entry groove 41 is provided in which a stem end portion 7a passing through the above-mentioned portion can continue. According to this embodiment, at rest, the stem end 7a is
Since it enters not only the third entry holes 33, 14, and 18 but also the entry groove 41 of the cam 19, the valve stroke is absorbed by these entry holes and the entry groove. Therefore, the height of the piston 30 can be further reduced by the depth of the entry groove 41, and the valve train can be formed most compact in the height direction.

FIG. 8 shows a valve mechanism with a pause mechanism of the third embodiment, which differs from the first embodiment only in that the shims are omitted. According to this embodiment, substantially the same effects as those of the first embodiment are obtained except that it is difficult to adjust the valve clearance.

Next, FIG. 9 shows the valve operating mechanism with a pause mechanism of the fourth embodiment, in which the shim is omitted and the cam 19 is followed by the stem end portion 7a which has entered the second entry hole 14. It differs from the third embodiment only in that a possible entry groove 41 is provided.

In the first to fourth embodiments, since the space for mounting the return spring 31 in the piston guide 20 is narrow, the return spring 31 having a high spring constant (and therefore a large spring load) may be employed. difficult. If the spring constant of the return spring 31 is low, it takes time to displace the piston 30 to the right due to the repulsive force, and the switching of the intake / exhaust valve 6 from the rest state to the operating state may be delayed.

Also, for example, even if a return spring 31 having a high spring constant can be adopted, it takes time to displace the piston 30 to the left by hydraulic pressure against the large spring load. Since there is a possibility that the switching from the operating state to the rest state may be delayed, a high oil pressure that greatly exceeds the spring load is required.

FIGS. 10 to 10 can improve these problems.
12 is a valve train with a pause mechanism of a fifth embodiment shown in FIG. This embodiment differs from the first embodiment only in the following points. Members common to the first embodiment are denoted by the same reference numerals as in the first embodiment, and description thereof will be omitted.

The cylinder head 1 is provided with an operating oil flow path 42 and a resting oil flow path 44 arranged vertically one above the other, and the operation oil flow path 42 is opened on the inner peripheral surface of the lifter guide hole 2. The annular passage 43 for suspension and the annular passage 45 for suspension in which the oil passage 44 for suspension is opened are recessed vertically. Each oil passage 4
2, 44 are switching valves 46 controlled by a computer 47.
Is selectively connected to the pump 36 or the oil pan 40.

On the upper left side of the peripheral wall 13 of the lifter 11 in FIG. 10 and the like, an operating lifter oil groove 1 is formed by flattening the outer peripheral surface of the peripheral wall 13 so that it can communicate with the operating annular passage 43.
01 and two operating lifter communication holes 102 penetrating the groove bottom. On the lower right side of the peripheral wall 13 in FIG. 10 etc., a lifter oil groove 103 for suspension formed by flatly recessing the outer peripheral surface of the peripheral wall 13 so as to be able to communicate with the annular passage 45 for suspension, and penetrates the groove bottom. There are provided two lifter communication holes 104 for stopping. The operating lifter oil groove 101 and the resting lifter oil groove 103 are provided only when the base circle of the cam 19 corresponds to the lifter 11 as shown in FIGS. 10 and 11, respectively. When the nose of the cam 19 presses the lifter 11 as shown in FIG. 12, the communication is cut off.

The piston guide 20 is integrally formed with a peripheral wall 201 extending downward from the peripheral edge thereof, and the peripheral wall 201 is press-fitted and fixed to the peripheral wall 13 of the lifter 11. Peripheral wall 20
A lower motion spring 202 in place of the lost motion spring 21 of the first embodiment abuts on the lower end surface of the piston 1 to urge the piston guide 20 upward.

In the cylinder groove 22 of the piston guide 20, an operating pressure chamber 203 is provided between the left end surface of the piston 30 and the left end of the piston guide 20, as shown in FIG.
Is formed, as shown in FIG.
A rest pressure chamber 204 is formed between the right end surface of the piston 30 and the right end of the piston guide 20.

The return spring 31 of this embodiment includes:
As compared with that of the first embodiment, a spring having a lower spring constant and therefore a smaller spring load is selected. This is because the return spring 31 of the present embodiment only returns the piston 30 to the right when the internal combustion engine is stopped and the oil pressure is cut off, and enables the intake and exhaust valve 6 to be operable at the next start of the internal combustion engine. Because it is a thing. A spring engagement groove 34 into which one end of the return spring 31 is engaged is formed in the left end surface of the piston 30 to prevent the return spring 31 from coming off.

On the left side of the piston guide 20 in FIG. 10 and the like, an operating piston guide oil groove 205 formed by flattening the outer peripheral surface of the peripheral wall 201 so as to communicate with the operating lifter communication hole 102, The groove 205 is connected to the pressure chamber 20 for operation.
3 communicating piston guide communication holes 20
6 are provided. On the right side of the piston guide 20 in FIG. 10 and the like, a resting piston guide oil groove 207 formed by flattening the outer peripheral surface of the peripheral wall 201 so as to be able to communicate with the resting lifter communication hole 104, Two pause piston guide communication holes 208 for communicating the pressure chamber 207 with the pressure chamber 204 are provided.

Therefore, when the switching valve 46 is switched as shown in FIG.
Only at the time corresponding to 1, the pump 36 → the oil supply pipe 38 → the switching valve 46 → the operating oil flow path 42 → the operating annular path 43 → the operating lifter oil groove 101 → the operating lifter communication hole 102 → the operating piston guide oil. The engine oil is pumped and supplied through an operating hydraulic circuit of the groove 205 → the operating piston guide communication hole 206 → the operating pressure chamber 203, and the piston 30 is displaced to the right at high speed by the oil pressure. Is in the operating state as in the first embodiment. At this time, the engine oil in the pressure chamber for suspension 204 is discharged through the next hydraulic circuit for suspension in the opposite direction.

When the switching valve 46 is switched as shown in FIG. 11, the base circle of the cam 19 is
Only when the above-mentioned condition is satisfied, the pump 36 → the oil supply pipe 38 → the switching valve 46 → the resting oil flow path 44 → the resting annular path 45 → the resting lifter oil groove 103 → the resting lifter communication hole 104 → the resting piston guide oil groove. 207 → piston guide communication hole 208 for rest → engine oil is pressure-fed and supplied through a rest hydraulic circuit of the pressure chamber 204 for rest, and the piston 30 is displaced to the left at high speed against the repulsive force of the return spring 31. Then, the intake / exhaust valve 6 is in a rest state as in the first embodiment. At this time, the engine oil in the working pressure chamber 203 is discharged through the working hydraulic circuit in the opposite direction.

When the internal combustion engine stops and the hydraulic pressure is cut off, as shown in FIG.
1 returns the piston 30 to the right and prepares the intake / exhaust valve 6 to be operable at the next start of the internal combustion engine. As described above, since the spring load of the return spring 31 is small, the speed at which the piston 30 is returned to the right is low, but there is no problem because the internal combustion engine is stopped.

As described above, according to this embodiment, the hydraulic circuit for operating and stopping the intake / exhaust valve 6 is provided, and the piston 30 is bidirectionally displaced at high speed by the hydraulic pressure. Both the switching to the operating state and the switching from the operating state to the rest state can be performed more smoothly and instantly as compared with those of the first to fourth embodiments.

As described above, the return spring 3
Since the spring load of (1) can be significantly reduced as compared with that of the first to fourth embodiments, the above-mentioned state can be switched even when the hydraulic pressure is low.

In the present embodiment, even if the return spring 31 malfunctions due to some kind of abnormality such as the entry of foreign matter, the bidirectional displacement of the piston 30 is not changed.
Since it is performed by hydraulic pressure and does not depend on the return spring 31, there is no fear that the switching of the state becomes impossible.
The reliability can be further improved.

As described above, the oil is supplied only when the base circle of the cam 19 corresponds to the lifter 11 at the time of switching from the resting state to the operating state and at the time of switching from the operating state to the resting state. The amount of engine oil leakage is, for example, 20 to 30% lower than that of the first to fourth embodiments.
Can be reduced. On the other hand, the nose of the cam 19 is lifter 11
No oil is replenished when the pressure is pressed, but there is no problem because the piston 30 does not move at that time. That is, the piston 30 is stopped by the load of the valve spring 10 at the time of operation and the stem end 7a at the time of rest. Because it has stopped due to the approach of

Next, some modifications of the return spring 31 or its mounting structure will be described for each purpose.

(1) Improvement of Performance and Reliability of Spring First, the return spring 1 of the modification (1) shown in FIG.
11 is formed by winding a spring wire in a coil shape and extending its ends in a C shape so as not to cross each other when viewed from a plane.
It is a short torsion coil spring. The return spring 31 of the first embodiment is deformed so that the coil spring opens (expands the diameter) when pushed by the piston 30, but the return spring 111 of the modified example (1) The spring deforms to close (reduce the diameter). According to the modification (1), the spring load can be increased and the stress can be reduced with the same wire diameter and the same number of turns as compared with the return spring 31 of the first embodiment.

The return spring 112 of the modified example (2) shown in FIG. 14 is different from the return spring 31 of the modified example (1) in that the end contacting the piston 30 is bent in a U-shape. . According to the modified example (2), the contact area with the piston 30 increases, so that the reliability can be improved.

(2) Preventing the return spong from coming off at the time of assembly In a modification (3) shown in FIG. 15, the return spring is formed by deforming a pair of projections 113 provided on the bottom of the return spring mounting groove 23. This embodiment is different from the first embodiment in that the end of 31 is fixed by caulking.

The modification (4) shown in FIG. 16 is different from the first embodiment in that the bent end of the return spring 31 is inserted into the locking hole 114 formed in the bottom of the return spring mounting groove 23 and locked. This is different from one embodiment.

In a modification (5) shown in FIG. 17, a pin 115 is passed through a through hole formed in the bottom of the return spring mounting groove 23, and the coil portion of the return spring 31 is fitted over the pin 115 and locked. The first embodiment is different from the first embodiment in that the pin 115 is removed after the piston guide 20 is pressed into and fixed to the lifter. The through hole from which the pin 115 has been removed acts as an air vent when the piston is operated.

In a modification (6) shown in FIG. 18, the end of the return spring 111 is wound several times, and the end of the return spring 111 is elastically brought into contact with the inside of the return spring mounting groove 23. The difference from the modification (1) is that the end of the spring 111 is fixed.

In a modification (7) shown in FIG. 19, the position of the return spring mounting groove 23 is shifted laterally to the cylinder groove,
That the position of the end of the return spring 118 has been changed,
The end portion is wound several times (the diameter of the return portion is larger than the coil portion, so that the return spring 118 itself can be prevented from slipping). This is different from the first embodiment in that the end of the return spring 118 is fixed by the reaction force.

According to these modified examples (3), (4), (5), (6), and (7), after the return springs 31, 111, and 118 are fitted in the return spring mounting grooves 23, the piston guide 20 is attached. Since the return springs 31, 111, 118 do not come off from the return spring mounting groove 23 until the press-fitting and fixing to the lifter are completed, the assemblability can be improved.

(3) Reduction of the Number of Parts The modification (8) shown in FIG. 20 is a modification of the return spring mounting groove 23 and the return spring 11 on both sides of the piston 30.
9 is different from the first embodiment in that the end portions 9 are connected to each other to be integrated.

The return spring 120 of the modification (9) shown in FIG. 21 is a plate spring integrated in an arc shape.

According to these modified examples (8) and (9), since the return springs 119 and 120 are respectively integrated, the number of parts can be reduced as compared with the above embodiment.

As an application, the above-mentioned modified examples (1) to
(9) can be further modified or combined.

The present invention is not limited to the configuration of the above-described embodiment, but can be embodied with appropriate modifications without departing from the spirit of the invention.

[0073]

As described above in detail, according to the first aspect of the present invention, the valve operating mechanism with a pause mechanism is compact in the height direction despite having the pause mechanism. And the weight can be reduced, which is advantageous in terms of fuel efficiency, the inertial weight of the valve train is reduced, and the followability of the valve train to the high-speed rotation of the internal combustion engine is improved. . In addition to the above effects, the piston
Is formed into a thin plate shape, so if its height can be reduced
In both cases, the first entry hole can be easily formed. Moreover, the back
Low return spring biases piston in one direction
To minimize space in the height direction.
Suitable for

Further, according to the valve mechanism according to the second aspect of the invention, the piston guide, the cylinder groove and the piston
Can be easily processed.

According to the third aspect of the present invention, the piston guide, the cylinder groove and the piston can be easily machined, and the sealing performance of the hydraulic pressure is improved, so that a decrease in the hydraulic pressure can be prevented.

According to the valve mechanism according to the fourth aspect of the present invention, the height of the return spring can be minimized,
The return spring can be housed in the piston guide.

According to the fifth aspect of the present invention, the valve mechanism is not bulky in the height direction.
A shim can be attached, so that the valve clearance can be easily adjusted.

According to the sixth aspect of the present invention, the height of the piston may be reduced by the depth of the entrance groove provided in the cam. There is no need to worry about bulkiness in the direction, and it can be formed compact.

Further, according to the valve operating mechanism of the present invention, the valve operating mechanism can be formed most compact in the height direction.

According to the valve operating mechanism of the present invention, the switching from the idle state to the operating state and the switching from the operating state to the idle state can be performed more smoothly and instantaneously. . When a return spring is provided, the spring load can be reduced, so that the state can be switched even when the hydraulic pressure is low. In addition, even if the return spring malfunctions due to some kind of abnormality such as the entry of foreign matter, there is no fear that the switching of the state becomes impossible, and the reliability can be further improved.

Further, according to the valve operating mechanism of the ninth aspect, the amount of engine oil leakage can be reduced.

According to the valve mechanism according to the tenth aspect, the assemblability of the piston guide and the return spring can be improved.

[Brief description of the drawings]

FIGS. 1A and 1B show a valve operating mechanism according to a first embodiment of the present invention, in which FIG. 1A is a cross-sectional view when an intake / exhaust valve is operated, and FIG.
FIG. 3 is a cross-sectional view taken along line Ib-Ib of FIG.

2 (a) is a cross-sectional view when the intake / exhaust valve is stopped, and FIG. 2 (b) is a cross-sectional view taken along line IIb-IIb of FIG. 2 (a).

3A and 3B show a shim of the same valve mechanism, wherein FIG.
(B) is a sectional view taken along line IIIb-IIIb of (a).

4A and 4B show a lifter of the same valve mechanism, wherein FIG.
(B) is a sectional view taken along line IVb-IVb of (a).

5 (a) is a plan view, FIG. 5 (b) is a sectional view taken along line Vb-Vb of FIG. 5 (a), and FIG.
FIG. 3 is a sectional view taken along line Vc-Vc of FIG.

6 (a) is a plan view, and FIG. 6 (b) is a sectional view taken along the line VIb-VIb of FIG. 6 (a).

FIG. 7 is a sectional view of a main part showing a valve train of a second embodiment.

FIG. 8 is a sectional view of a main part showing a valve train of a third embodiment.

FIG. 9 is a cross-sectional view of a principal part showing a valve mechanism of a fourth embodiment.

10A and 10B show a valve operating mechanism according to a fifth embodiment, wherein FIG. 10A is a cross-sectional view when the intake / exhaust valve is operated, and FIG.
It is Xb line sectional drawing.

11A and 11B show the same valve mechanism, wherein FIG. 11A is a cross-sectional view of the intake / exhaust valve at the time of rest switching, and FIG. 11B is XIb-XI of FIG.
It is a sectional view taken on line b.

12A and 12B show the same valve mechanism, wherein FIG. 12A is a cross-sectional view when the intake / exhaust valve is at rest, and FIG. 12B is a sectional view taken along line XIIb-XII of FIG.
It is a sectional view taken on line b.

FIG. 13 is a plan view of a modified example (1) of a return spring or its mounting structure.

FIG. 14 is a side view of a modified example (2) of the return spring or its mounting structure.

FIG. 15 is a plan view of a modified example (3) of the return spring or its mounting structure.

16A and 16B show a modified example (4) of a return spring or a mounting structure thereof, wherein FIG. 16A is a plan view and FIG. 16B is a partial sectional view.

FIGS. 17A and 17B show a modified example (5) of the return spring or its mounting structure, wherein FIG. 17A is a plan view and FIG. 17B is a partial sectional view.

FIG. 18 is a plan view of a modified example (6) of the return spring or its mounting structure.

FIG. 19 is a plan view of a modified example (7) of the return spring or its mounting structure.

FIG. 20 is a plan view of a modified example (8) of the return spring or its mounting structure.

FIG. 21 is a plan view of a modified example (9) of the return spring or its mounting structure.

FIG. 22 is a cross-sectional view showing a conventional valve train.

FIG. 23 is an essential part cross-sectional view showing the same valve operating mechanism in another cutting direction.

FIG. 24 is a cross-sectional view of a main part showing a modification of the conventional valve train.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Cylinder head 2 Lifter guide hole 6 Intake / exhaust valve 11 Lifter 12 End wall 14 Second entrance hole 16 Lifter communication hole 17 Shim 18 Third entrance hole 19 Cam 20 Piston guide 22 Cylinder groove 23 Return spring mounting groove 26 Piston guide communication hole Reference Signs List 30 piston 31 return spring 32 pressure chamber 33 first entry hole 35 oil flow path 41 entry groove 42 operation oil flow path 44 resting oil flow path 102 actuation lifter communication hole 104 resting lifter communication hole 111, 112, 118, 119, 120 Return spring 203 Operating pressure chamber 204 Resting pressure chamber 206 Actuating piston guide communication hole 208 Resting piston guide communication hole

Claims (10)

(57) [Claims] 1. An inverted cup-shaped lifter slidably inserted into a lifter guide hole of a cylinder head and transmitting a cam action of a cam to an intake / exhaust valve, and an axial center direction of the intake / exhaust valve inside the lifter. A piston which reciprocates in a direction substantially orthogonal to the first direction, wherein the piston is provided with a first entry hole through which a stem end of the intake / exhaust valve can enter, and an end wall of the lifter enters the first entry hole. A second entry hole through which the end of the stem that has passed through can enter is provided , and the piston is formed into a thin plate shape.
Formed and made of torsion coil spring or leaf spring short
The return spring urges the piston in one direction
A valve train with a stop mechanism for an internal combustion engine. 2. Sliding in lifter guide hole of cylinder head
Inserted to transmit the cam action of the cam to the intake and exhaust valves
An inverted cup-shaped lifter, and the suction and discharge inside the lifter.
A piston that reciprocates in a direction substantially perpendicular to the axis of the air valve
The piston has a stem end portion of the intake / exhaust valve.
Providing a first entrance hole capable of entering, the end wall of the lifter
The end of the stem that has passed through the first entry hole continues to enter
Provide a possible second entry hole and make the piston into a thin plate shape
Form a cylinder groove on one side of a substantially disk-shaped piston guide
The piston is slidable in the cylinder groove.
A valve train with a stop mechanism for an internal combustion engine, wherein the valve train is inserted . 3. Sliding in lifter guide hole of cylinder head
Inserted to transmit the cam action of the cam to the intake and exhaust valves
An inverted cup-shaped lifter, and the suction and discharge inside the lifter.
A piston that reciprocates in a direction substantially perpendicular to the axis of the air valve
The piston has a stem end portion of the intake / exhaust valve.
Providing a first entrance hole capable of entering, the end wall of the lifter
The end of the stem that has passed through the first entry hole continues to enter
Provide a possible second entry hole and make the piston into a thin plate shape
A cylinder groove is recessed on one side of a substantially disk-shaped piston guide, the piston is slidably inserted into the cylinder groove, the piston guide is press-fitted and fixed inside the lifter, and the cylinder groove is formed. A pressure chamber is formed between the piston and the piston guide, a piston guide communication hole for supplying engine oil to the pressure chamber is provided in the piston guide, and a lifter communication hole communicating with the piston guide communication hole is formed in the lifter. provided, wherein the lifter passage inner combustion engine stop mechanism with the valve mechanism to the oil passage communicating with you <br/> characterized in that provided in the cylinder head. 4. A return spring mounting groove is recessed at an end of a cylinder groove in the piston guide, a short return spring is fitted into the return spring mounting groove, and the piston is moved in one direction by the return spring. 4. A valve train with a stop mechanism for an internal combustion engine according to claim 2, wherein the valve train is biased. 5. Sliding in lifter guide hole of cylinder head
Inserted to transmit the cam action of the cam to the intake and exhaust valves
An inverted cup-shaped lifter, and the suction and discharge inside the lifter.
A piston that reciprocates in a direction substantially perpendicular to the axis of the air valve
The piston has a stem end portion of the intake / exhaust valve.
Providing a first entrance hole capable of entering, the end wall of the lifter
The end of the stem that has passed through the first entry hole continues to enter
A possible second entry hole was provided, a shim was attached to the end wall of the lifter, and a third entry hole was provided to allow the stem end portion to enter the second entry hole, followed by the stem end. pause mechanism with a valve operating mechanism of the internal combustion engine shall be the characterized in that. 6. Sliding in lifter guide hole of cylinder head
Inserted to transmit the cam action of the cam to the intake and exhaust valves
An inverted cup-shaped lifter, and the suction and discharge inside the lifter.
A piston that reciprocates in a direction substantially perpendicular to the axis of the air valve
The piston has a stem end portion of the intake / exhaust valve.
Providing a first entrance hole capable of entering, the end wall of the lifter
The end of the stem that has passed through the first entry hole continues to enter
The second access holes can be provided, with halting mechanism of the internal combustion engine enters the by the stem end followed passed through you characterized in that a penetration possible entry groove to said second access holes in the cam Valve train. 7. An operation of the internal combustion engine with a stop mechanism according to claim 5, wherein the cam is provided with an entry groove in which the end of the stem that has entered the third entry hole can continue. Valve mechanism. 8. An operating pressure chamber is formed between one end surface of the piston and a piston guide, and a stop pressure chamber is formed between the other end surface of the piston and the piston guide. And an operation piston guide communication hole and a suspension piston guide communication hole for supplying engine oil to the suspension pressure chamber, respectively, are provided in the piston guide, and communicate with the operation piston guide communication hole and the suspension piston guide communication hole, respectively. An operation lifter communication hole and a suspension lifter communication hole are provided in the lifter, and an operation oil flow path and a suspension oil flow path communicating with the operation lifter communication hole and the suspension lifter communication hole are provided in the cylinder head. 5. A valve train with a stop mechanism for an internal combustion engine according to claim 3, wherein 9. The operation lifter communication hole and the suspension lifter communication hole, and the operation oil flow path and the suspension oil flow path,
9. The valve train with a stop mechanism for an internal combustion engine according to claim 8, wherein the cam is provided so as to communicate with each other only when the base circle of the cam corresponds to the lifter. 10. A valve mechanism with a stop mechanism for an internal combustion engine according to claim 4, further comprising: a disengagement preventing means for stopping said return spring with respect to said return spring mounting groove.