JPH07317518A - Valve system having pause mechanism for internal combustion engine - Google Patents

Abstract

PURPOSE:To provide a valve system having a pause mechanism which shows a compact size in a height direction, light weight, and can adjust a valve clearance. CONSTITUTION:An inverted cup-like lifter 11 transmits cam action of a cam 19 to an intake/exhaust valve 6. A piston 30 reciprocates inside the lifter 11 in a direction substantially perpendicular to an axis of the intake/exhaust valve 6. A first entrance hole 33 is formed on the piston 30, which hole 33 a stem end 7a of the intake/exhaust valve 6 can enter. A second entrance hole 14 is formed on an end wall 12 of the lifter 11, which hole 14 the stem end 7a can enter through the first entrance hole 33. A shim 17 is installed on the end wall 12. A third entrance hole 18 is formed on the shim 17, which hole 18 the stem end 7a can enter through the second entrance hole 14.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art This type of valve operating mechanism with a pause mechanism is effective in reducing the fuel consumption amount when the internal combustion engine is actually used. The applicant of the present invention discloses in Japanese Patent Laid-Open No. 63-16112 that a piston guide 52 made of a light alloy or a synthetic resin is formed separately from the inverted cup-shaped lifter 51 as shown in FIGS. 22 and 23. A cylinder hole 53 formed in the lifter 51 and formed in the piston guide 52 thereof.
A valve mechanism with a pause mechanism is proposed in which a piston 54 having a substantially round bar shape is reciprocally fitted. The stem end portion 57 of the intake / exhaust valve 56 is inserted into the stem hole 55 provided through the piston 54.
The valve stroke is absorbed by the stem hole 55 and the intake / exhaust valve 56 is brought into a resting state when the vehicle enters. A similar technique is disclosed in Japanese Utility Model Laid-Open No. 61-134504.

According to this valve actuation mechanism with a rest mechanism, a cylinder hole is formed in the lifter itself and a piston is inserted into the cylinder hole as in the prior art, for example, Japanese Patent Laid-Open No. 61-8416. Compared with the example, the effect of being lighter and easier to process and assemble was obtained.

[0004]

However, the conventional valve operating mechanism with a pause mechanism proposed by the present applicant also has the following problems.
The following problems remained. Since it is necessary to increase the height of the stem hole 55, that is, the height of the piston 54 in order to absorb the valve stroke at rest, as shown in FIG. 22, the dimension from the lower surface of the piston 54 to the upper surface of the end wall of the lifter 51. Was increased and bulky in the height direction, and space was restricted. Since the piston 54 having a high height is provided, the weight of the piston 54, the piston guide 52, and the lifter 51 is increased, which is disadvantageous in terms of fuel consumption and the inertial weight of the valve operating mechanism is increased, thereby increasing the speed of the internal combustion engine. There is a possibility that the followability of the valve operating mechanism with respect to rotation may deteriorate. Since there was no means for adjusting the valve clearance, the adjustment was extremely difficult. Therefore, as shown in FIG. 24, a structure in which a shim 58 for adjusting the valve clearance is mounted on the end wall of the lifter 51 is conceivable.

An object of the present invention is to solve the above problems, to provide a valve operating mechanism with a resting mechanism, which can be made compact in the height direction, can be reduced in weight, and can be adjusted in valve clearance. Especially.

[0006]

In order to achieve the above object, a valve operating mechanism with a resting 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 inside the lifter in a direction substantially orthogonal to the axial center direction of the intake / exhaust valve, and the stem end of the intake / exhaust valve can enter the piston. A second entrance hole is provided in the end wall of the lifter so that the stem end that has entered the first entrance hole can subsequently enter.

The piston is preferably formed in the shape of a thin plate.

Further, a cylinder groove is provided on one surface 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, so that the piston in the cylinder groove A pressure chamber is formed between the piston guide and the piston guide communication hole that supplies engine oil to the pressure chamber is provided in the piston guide, and a lifter communication hole that communicates with the piston guide communication hole is provided in the lifter and communicates with the lifter communication hole. It is advisable to provide an oil passage for the cylinder head.

Then, a return spring mounting groove is provided at the end of the cylinder groove in the piston guide, a short return spring is fitted in the return spring mounting groove, and the return spring urges the piston in one direction. be able to. Here, as the short return spring, a torsion coil spring, a leaf spring or the like can be exemplified. The torsion coil spring is a spring formed by winding a spring wire in a coil shape and extending both ends thereof to exert elasticity in a torsion direction.

Next, a shim may be attached to the end wall of the lifter, and the shim may be provided with a third entrance hole into which the stem end portion that has entered the second entrance hole can subsequently enter.

Further, the cam may be provided with an entrance groove into which the stem end part, which has entered the second entrance hole, can subsequently enter.

Further, it is also possible to combine the third entry hole and the entry groove, that is, to provide the cam with an entry groove into which the stem end part that has gone through the third entry hole can continue.

Further, an operating pressure chamber is formed between one end surface of the piston and the piston guide, and a resting pressure chamber is formed between the other end surface of the piston and the piston guide. A piston guide communication hole for operation and a piston guide communication hole for rest that supply engine oil to the pressure chambers are provided in the piston guide, and an operation lifter communication hole that communicates with the operation piston guide communication hole and the rest piston guide communication hole, respectively. It is also possible to provide the lifter communication hole for rest and the lifter, and to provide the working oil passage and the rest oil passage which are respectively communicated with the operation lifter communication hole and the rest lifter communication hole in the cylinder head.

Further, the operating lifter communicating hole and the resting lifter communicating 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. It is preferable.

Next, it is also preferable to provide disengagement prevention means for stopping the return spring in the return spring mounting groove.

[0016]

According to the valve operating mechanism with the pause mechanism of the internal combustion engine according to the present invention, the stem end portion of the intake and exhaust valve is
Since it enters into the first entrance hole provided in the piston inside the lifter and then into the second entrance hole provided in the end wall of the lifter, the valve stroke is made by these first and second entrance holes. Be absorbed. Therefore, compared with 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 mechanism can be made compact in the height direction. Can be formed. Also, since the weight of the piston, lifter, etc. can be reduced by the amount that the height of the piston can be lowered, it is advantageous in fuel consumption and the inertial 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.

Particularly, if the piston is formed in the shape of a thin plate, the height can be reduced and the first entrance hole can be easily formed.

If a cylinder groove is provided on one surface of the substantially disk-shaped piston guide and the piston is slidably inserted into the cylinder groove, these piston guide, cylinder groove and piston can be easily formed. Can be processed. The 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 brought into pressure contact with each other to seal the hydraulic pressure, so that the hydraulic pressure is prevented from decreasing.

A return spring mounting groove is provided at the end of the cylinder groove in the piston guide, and a short return spring is fitted in the return spring mounting groove, and the return spring mounts the piston in one direction. By urging the return spring, the height of the return spring can be minimized and the return spring can be housed in the piston guide. If a pair of return springs are symmetrically arranged on both sides of the piston and the return springs bias the pistons, the pistons can be biased smoothly without deviation.

Next, if a shim is attached to the end wall of the lifter and a third entrance hole is provided in this shim, the stem end of the intake / exhaust valve has only the first and second entrance holes at rest. In addition, the valve stroke is absorbed by the first to third entry holes because the entry also enters the third entry hole of the shim.
Therefore, even if the shim is mounted, the height of the piston needs to be further reduced by the thickness of the shim, so that the valve mechanism does not have to be bulky in the height direction and can be formed compactly. The valve clearance can be easily adjusted by selectively mounting a shim having a desired thickness from shims having various thicknesses.

Further, if the cam is provided with an entrance groove, the stem end of the intake / exhaust valve enters not only the first and second entrance holes but also the cam entrance groove at rest. The valve stroke is absorbed by the entry hole and the entry groove. Therefore, since the height of the piston needs to be further reduced by the depth of the entry groove, the valve mechanism does not have to be bulky in the height direction, and the valve mechanism can be made compact.

Further, by combining the third admission hole and the admission groove, that is, by providing the shim with the third admission hole and the cam with the admission groove, the stem end of the intake and exhaust valve is Since the first to third entrance holes and the entrance groove also enter, the valve stroke is absorbed by these entrance holes and entrance grooves. Therefore, the valve mechanism can be formed to be the most compact in the height direction.

Further, an operating pressure chamber is formed between one end surface of the piston and the piston guide, and a resting pressure chamber is formed between the other end surface of the piston and the piston guide. A piston guide communication hole for operation and a piston guide communication hole for rest that supply engine oil to the pressure chambers are provided in the piston guide, and an operation lifter communication hole that communicates with the operation piston guide communication hole and the rest piston guide communication hole, respectively. And a lifter communication hole for suspension are provided in the lifter, and an oil passage for operation and an oil passage for suspension which respectively communicate with the lifter communication hole for operation and the lifter communication hole for suspension are provided on the cylinder head, the piston is hydraulically operated. Can be displaced bidirectionally at high speed, and switching from resting state to working state and from working state to resting state can be performed smoothly and instantaneously. It can be carried out in. Further, when the return spring is provided, the spring load can be reduced, so that the above state can be switched even if the hydraulic pressure is low. Further, even if the return spring malfunctions due to some abnormality such as foreign matter mixed in, there is no concern that the state switching will be impossible.

Further, the operating lifter communicating hole and the resting lifter communicating 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. 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. Since the return spring does not come off from the return spring mounting groove by the end, the assembling property of the piston guide and the return spring can be improved.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a valve operating mechanism with a pause 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 pause mechanism of the first embodiment. 1 and 2 show the whole of the valve operating mechanism, in which a cylinder head 1 of an internal combustion engine has a lifter guide hole 2, a valve spring chamber 3 and an air passage 4 in order from the top.
And a pipe-shaped valve guide 5 is attached to the boundary wall between the valve spring chamber 3 and the airflow passage 4. The stem portion 7 of the intake / exhaust valve 6 is slidably fitted into the valve guide 5, and the stem portion 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. Between the retainer 8 and the inner bottom portion of the valve spring chamber 3, an intake / exhaust valve 6 is provided. 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 is slidably inserted into the lifter guide hole 2 as shown in FIG. A circular second entrance hole 14 through which the stem end 7a can enter is provided at the center of the end wall 12 in the vertical direction. Further, a lifter oil groove 15 is provided at the right end portion of the outer peripheral surface of the peripheral wall 13 in the drawing.
Further, the peripheral wall 13 is provided with a lifter communication hole 16 which allows the lifter oil groove 15 and a piston guide oil groove 25 described later to communicate with each other.

A disc-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 the convex wall 12a provided upright on the peripheral edge thereof. A circular third entrance hole 1 into which the stem end 7a having entered the second entrance hole 14 can subsequently enter in the center of the shim 17.
8 is provided so as to extend vertically. The upper surface of the shim 17 is in sliding contact with the cam 19, and since the width of the cam 19 in the thickness direction of the paper in FIG. 1 is larger than the diameter of the third entry hole 18, the cam 19 fits into the third entry hole 18. There is no entry.

Inside the lifter 11, a piston guide 2 made of an aluminum alloy and having a substantially disc shape 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 to urge the piston guide 20 upward without pushing the retainer 8 downward. Therefore, lost motion spring 2
1 is a valve spring 10 even when compressed to maximum
Has a low spring constant so as not to 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 portion 7 is formed.
2 is provided as a recess, and a pair of return spring mounting grooves 23, which are deeper than the cylinder groove 22, are provided on both sides of the left end portion of the cylinder groove 22 in the drawing. The cylinder groove 22 forms a cylinder hole with the lower surface of the end wall 12. At the center of the piston guide 20, the stem end 7
The stem hole 24 in the vertical direction through which a is always inserted is provided,
The stem hole 24 intersects with the cylinder groove 22. A piston guide oil groove 25 that communicates with the lifter communication hole 16 is formed at the right end portion of the piston guide 20 in the drawing, and a piston guide oil groove 25 that communicates with the pressure chamber 32 described later is further formed. Communication hole 2
6 is transparently provided. 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, it is possible to prevent the hydraulic pressure in the piston guide oil groove 25 from decreasing.

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 surface of the piston 30 in the drawing is formed in a plane arc shape, and the right end surface in the drawing is formed in a flat corner shape like the right end surface of the piston guide 20. In the pair of return spring mounting grooves 23, a pair of return springs using a short torsion coil spring formed by winding a spring wire into a coil shape and extending both ends thereof in a V shape so as to intersect each other when seen from a plane. 31 are fitted, one end of each return spring 31 abuts on the left end face of the piston 30, and the other end abuts on the left end face of the return spring mounting groove 23 in the figure, thereby urging the piston 30 to the right. is 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 formed between the right end surface of the piston 30 and the right end surface 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 in the reverse path. Then, the piston 30 is displaced rightward by the repulsive force of the return spring 31.

On the right side of the piston 30, the stem end 7a is formed.
A first entry hole 33 having a circular shape that allows the entry of is penetrated in the vertical direction. Then, when the piston 30 is displaced to the left as described above, the first entrance hole 33 becomes the stem hole 2
4, the second entrance hole 14 and the third entrance hole 18 are coincident with, and the stem end portion 7a enters into them. Further, when the piston 30 is displaced rightward as described above, the first entry hole 33 is misaligned with the stem hole 24, the second entry hole 14 and the third entry hole 18, and the stem end 7a is the piston end. The lower surface of 30 is abutted.

The cylinder head 1 is provided with an oil passage 35 that opens into the lifter oil groove 15, and 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 done. The engine oil is discharged from the pressure chamber 32 to the oil pan 40 via the switching valve 37 and the oil discharge pipe 39. The switching valve 37 is controlled by a computer (not shown).

The valve mechanism with the suspension mechanism of this embodiment operates as follows. First, when the internal combustion engine has a high load, as shown in FIG.
As shown in, 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, no pressure is applied to the pressure chamber 32, and 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 that is 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 to open the intake / exhaust valve 6.
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 when the internal combustion engine is under a low load, as shown in FIG. 2, the switching valve 37 is switched so that the pressure chamber 32 and the pump 36 are communicated with each other according to a command from the computer. To be Therefore, the engine oil is pressure-fed to the pressure chamber 32 through the above-mentioned path and a 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 and enters the first entrance hole 33, then the second entrance hole 14, and then the third entrance hole 18. When the cam 19 rotates in this state, the lifter 11 and 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 only repeats compression and restoration of itself, 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 in a rest state.

According to the valve operating mechanism with the resting mechanism of the present embodiment as described above, the end wall 12 of the lifter 11 and the shim 17 are different from the conventional example in which the valve stroke is absorbed only by the stem hole of the piston. Piston 3 for both thicknesses
The height of 0 can be reduced, and the dimension from the lower surface of the piston 30 to the upper surface of the end wall 12 can be reduced, so that the valve mechanism can be formed compact in the height direction. 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 the amount that the height of the internal combustion engine can be reduced, it is advantageous in fuel consumption, and the inertial weight of the valve mechanism is reduced, so The followability of the valve mechanism is also improved.

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 of the second embodiment, in which the cam 19 (viewed from the side of 90 degrees with respect to FIG. 1) enters the third entrance hole 18. The present embodiment is different from the first embodiment only in that an entry groove 41 into which the stem end 7a that has passed through can be subsequently entered is provided. According to this embodiment, at rest, the stem end 7a is
Not only the third entry holes 33, 14, 18 but also the entry groove 41 of the cam 19, the valve stroke is absorbed by these entry holes and the entry grooves. Therefore, the height of the piston 30 can be further reduced by the depth of the entry groove 41, and the valve mechanism can be formed most compact in the height direction.

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

Next, FIG. 9 shows a valve operating mechanism with a resting mechanism of the fourth embodiment, in which the shim is omitted and the stem end 7a that has passed through the second inlet hole 14 enters the cam 19 subsequently. It differs from the third embodiment only in that a possible entry groove 41 is provided.

By the way, in the above-mentioned first to fourth embodiments, since the mounting space of the return spring 31 in the piston guide 20 is narrow, the return spring 31 having a high spring constant (and hence 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 its repulsive force, which may delay the switching of the intake / exhaust valve 6 from the rest state to the operating state.

Even if the return spring 31 having a high constant can be employed, it takes time to displace the piston 30 leftward by hydraulic pressure against the large spring load, and the intake / exhaust valve 6 Since there is a possibility that the switching from the operating state to the rest state may be delayed, a high hydraulic pressure that greatly exceeds the spring load is required.

It is possible to improve these problems by referring to FIGS.
It is a valve operating mechanism with a pause mechanism of the fifth embodiment shown in FIG. This embodiment is different from the first embodiment only in the following points, and the members common to the first embodiment are designated by the same reference numerals as those of the first embodiment and the description thereof will be omitted.

The cylinder head 1 is provided with an operating oil passage 42 and a resting oil passage 44 which are vertically arranged side by side, and an operating oil passage 42 is opened on the inner peripheral surface of the lifter guide hole 2. The annular passage 43 and the resting annular passage 45 in which the resting oil passage 44 is opened are vertically provided in a recessed manner. Each oil flow path 4
2 and 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 flatly cutting the outer peripheral surface of the peripheral wall 13 so as to communicate with the operating annular passage 43.
01 and two operation lifter communication holes 102 penetrating the groove bottom are provided. Further, in the lower right portion of the peripheral wall 13 in FIG. 10 and the like, a rest lifter oil groove 103 formed by flatly recessing the outer peripheral surface of the peripheral wall 13 so as to communicate with the rest annular passage 45 and the groove bottom are penetrated. Two resting lifter communication holes 104 thus formed are provided. 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.

A peripheral wall 201 extending downward from the peripheral edge of the piston guide 20 is integrally formed, and the peripheral wall 201 is press-fitted and fixed to the peripheral wall 13 of the lifter 11. Perimeter wall 20
A lost motion spring 202, which replaces the lost motion spring 21 of the first embodiment, is in contact with the lower end surface of 1 to urge the piston guide 20 upward.

In the cylinder groove 22 of the piston guide 20, as shown in FIG. 10, between the left end face of the piston 30 and the left end of the piston guide 20, the working pressure chamber 203 is provided.
Are formed, and as shown in FIG.
A resting pressure chamber 204 is formed between the right end surface of the piston 30 and the right end of the piston guide 20.

In the return spring 31 of this embodiment,
As compared with that of the first embodiment, a spring constant is low and therefore a spring load is small. The reason for this is that the return spring 31 of the present embodiment only returns the piston 30 to the right when the internal combustion engine stops and the hydraulic pressure is cut off, and makes the intake / exhaust valve 6 operable at the next startup of the internal combustion engine. Because it is a thing. Further, a spring engaging groove 34 with which one end of the return spring 31 is engaged is recessed 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, there is an operating piston guide oil groove 205 formed by flatly recessing the outer peripheral surface of the peripheral wall 201 so as to communicate with the operating lifter communication hole 102, and the oil. The groove 205 is used as the pressure chamber 20 for operation.
Two working piston guide communication holes 20 that communicate with each other 3
And 6 are provided. Further, on the right side of the piston guide 20 in FIG. 10 and the like, there is a resting piston guide oil groove 207 formed by flatly recessing the outer peripheral surface of the peripheral wall 201 so as to communicate with the resting lifter communication hole 104, and the oil groove 207. Two resting piston guide communication holes 208 are provided for communicating the 207 with the resting pressure chamber 204.

Therefore, when the switching valve 46 is switched as shown in FIG. 10, the base circle of the cam 19 is moved to the lifter 1.
Only when corresponding to 1, the pump 36 → oil supply pipe 38 → switching valve 46 → operating oil flow passage 42 → operating annular passage 43 → operating lifter oil groove 101 → operating lifter communication hole 102 → operating piston guide oil The engine oil is pumped and supplied through the hydraulic circuit for operation of the groove 205 → the piston guide communication hole 206 for operation → the pressure chamber 203 for operation, and the piston 30 is displaced to the right at a high speed by the oil pressure, and the intake / exhaust valve 6 Is in the operating state as in the first embodiment. At this time, the engine oil in the pause pressure chamber 204 is discharged through the next pause hydraulic circuit in the reverse direction.

Further, when the switching valve 46 is switched as shown in FIG. 11, the base circle of the cam 19 is moved to the lifter 11.
Only when it corresponds to the pump 36 → oil supply pipe 38 → switching valve 46 → resting oil passage 44 → resting annular passage 45 → resting lifter oil groove 103 → resting lifter communication hole 104 → resting piston guide oil groove Engine oil is pumped and supplied through the hydraulic circuit for pause of 207 → piston guide communication hole for pause 208 → pressure chamber for pause 204, and the piston 30 is displaced leftward at high speed against the repulsive force of the return spring 31. Then, the intake / exhaust valve 6 is in the rest state as in the first embodiment. At this time, the engine oil in the operating pressure chamber 203 is discharged through the operating hydraulic circuit in the reverse direction.

When the internal combustion engine is stopped 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 in an operable state 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, hydraulic circuits for operating and stopping the intake / exhaust valve 6 are provided, and the piston 30 is displaced bidirectionally at high speed by the hydraulic pressure thereof. Both the switching to the operating state and the switching from the operating state to the resting state can be performed more smoothly and instantaneously than those of the first to fourth embodiments.

As described above, the return spring 3
Since the spring load of No. 1 can be significantly reduced as compared with that of the first to fourth embodiments, it is possible to switch between the states even if the hydraulic pressure is low.

In addition, even if the return spring 31 malfunctions due to some abnormality such as the entry of foreign matter, in this embodiment, the bidirectional displacement of the piston 30 is
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 above states becomes impossible,
The reliability can be increased.

Further, as described above, the structure is such that the oil is supplied only when the base circle of the cam 19 corresponds to the lifter 11 when switching from the rest state to the operating state and when switching from the operating state to the resting state. The engine oil leakage amount is, for example, 20 to 30% compared with that of the first to fourth embodiments.
It can be reduced. On the other hand, the nose of the cam 19 is the lifter 11.
No oil will be supplied when pressing, but there is no concern that the piston 30 will move at that time, so there is no problem at all. That is, the piston 30 is stopped by the load of the valve spring 10 during operation, and the stem end 7a during rest. This is because it has been stopped by the approach of.

Next, some modified examples of the return spring 31 or its mounting structure will be described according to purposes.

(1) Improvement of spring performance / reliability First, the return spring 1 of the modified example (1) shown in FIG.
Reference numeral 11 is formed by winding a spring wire into a coil and extending both ends thereof in a V shape so as not to intersect 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 is opened (expanded) when pushed by the piston 30, but the return spring 111 of the modified example (1) is coiled when pushed by the piston 30. It deforms so that the spring closes (diameter reduction). According to this modified example (1), compared with the return spring 31 of the first embodiment, the spring load can be increased and the stress can be reduced with the same wire diameter and the same number of turns.

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 folded back in a U shape. . According to this modification (2), the contact area with the piston 30 is increased, so that the reliability can be improved.

(2) Prevention of Return Spung Removal during Assembly In the modification example (3) shown in FIG. 15, the return spring is formed by deforming the pair of protrusions 113 provided on the bottom of the return spring mounting groove 23. It differs from the first embodiment in that the end of 31 is fixed by crimping.

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

In the modified example (5) shown in FIG. 17, the pin 115 is passed through the through hole formed in the groove bottom of the return spring mounting groove 23, and the coil portion of the return spring 31 is fitted onto the pin 115 and locked. This is different from the first embodiment in that the pin 115 is removed after the piston guide 20 is press-fitted and fixed to the lifter. The through hole after the pin 115 is removed serves as an air vent hole when the piston is operated.

In the modified example (6) shown in FIG. 18, the end portion of the return spring 111 is wound several times, and the outermost end thereof is elastically brought into contact with the inside of the return spring mounting groove 23, and the return force is returned by the reaction force. The difference from the modification (1) is that the end of the spring 111 is fixed.

In a modified example (7) shown in FIG. 19, the position of the return spring mounting groove 23 is laterally displaced from the cylinder groove,
The point where the position of the end of the return spring 118 is changed,
The end portion is wound several times (the diameter is larger than the coil portion, so that the return spring 118 itself can be prevented from being displaced), and the outermost end thereof is elastically abutted on the inside of the return spring mounting groove 23, and The difference from the first embodiment is that the end portion of the return spring 118 is fixed by a reaction force.

According to these modified examples (3), (4), (5), (6) and (7), the return springs 31, 111 and 118 are fitted into the return spring mounting groove 23, and then the piston guide 20 is mounted. Since the return springs 31, 111, 118 do not come off from the return spring mounting groove 23 before the press-fitting / fixing to the lifter is completed, the assembling property can be improved.

(3) Reduction of the number of parts In the modified example (8) shown in FIG. 20, the return spring mounting groove 23 and the return spring 11 on both sides of the piston 30 are provided.
9 is different from the first embodiment in that the respective end portions of 9 are integrated and integrated.

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

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

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

The present invention is not limited to the configuration of the above-described embodiment, and can be embodied by appropriately changing it without departing from the spirit of the invention.

[0073]

As described above in detail, according to the valve operating mechanism with the pause mechanism of the internal combustion engine according to the invention described in claim 1, the valve operating mechanism is compact in the height direction despite having the pause mechanism. In addition, since it is possible to reduce the weight of the internal combustion engine, the weight of the valve operating mechanism is reduced, and the inertial weight of the valve operating mechanism is reduced. .

In addition to the above effects, according to the valve operating mechanism of the second aspect of the present invention, the height of the piston can be reduced and the first entry hole can be easily formed.

Further, according to the valve mechanism of the third aspect of the present invention, the piston guide, the cylinder groove, and the piston can be easily machined, and the hydraulic sealing performance is improved to prevent the hydraulic pressure from decreasing.

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

According to the valve operating mechanism of the fifth aspect of the present invention, the valve operating mechanism is not bulky in the height direction,
Shims can be attached, and valve clearance can be adjusted easily.

According to the valve mechanism of the present invention, the height of the piston can be lowered by the depth of the entry groove formed in the cam. There is no need to worry about bulkiness in the direction, and it can be made compact.

Further, according to the valve mechanism of the invention as defined in claim 7, the valve mechanism can be formed to be the most compact in the height direction.

Further, according to the valve mechanism of the present invention, it is possible to smoothly and instantly switch from the rest state to the working state and from the working state to the rest state. . Further, when the return spring is provided, the spring load can be reduced, so that the above state can be switched even if the hydraulic pressure is low. Further, even if the return spring malfunctions due to some abnormality such as foreign matter mixed in, there is no concern that the state switching will be disabled, and the reliability can be further improved.

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

Further, according to the valve mechanism of the present invention, the assemblability of the piston guide and the return spring can be improved.

[Brief description of drawings]

FIG. 1 shows a valve mechanism of a first embodiment embodying the present invention, in which (a) is a cross-sectional view of an intake / exhaust valve during operation, (b).
FIG. 3B is a sectional view taken along line Ib-Ib of FIG.

2A and 2B show the valve operating mechanism, in which FIG. 2A is a cross-sectional view of the intake and exhaust valves at rest, and FIG. 2B is a cross-sectional view taken along line IIb-IIb of FIG.

FIG. 3 shows a shim of the valve operating mechanism, (a) is a plan view,
(B) is a IIIb-IIIb line sectional view of (a).

FIG. 4 shows a lifter of the valve operating mechanism, (a) is a plan view,
(B) is a IVb-IVb line sectional view of (a).

5A and 5B show a piston guide of the valve operating mechanism, FIG. 5A is a plan view, FIG. 5B is a sectional view taken along line Vb-Vb of FIG. 5A, and FIG.
FIG. 7A is a sectional view taken along line Vc-Vc of FIG.

6A and 6B show a piston of the valve mechanism, FIG. 6A is a plan view, and FIG. 6B is a sectional view taken along line VIb-VIb in FIG. 6A.

FIG. 7 is a cross-sectional view of essential parts showing a valve mechanism of a second embodiment.

FIG. 8 is a cross-sectional view of essential parts showing a valve mechanism of a third embodiment.

FIG. 9 is a cross-sectional view of essential parts showing a valve mechanism of a fourth embodiment.

FIG. 10 shows a valve mechanism of a fifth embodiment, (a) is a cross-sectional view of the intake and exhaust valves during operation, (b) is a cross-sectional view taken along line Xb- of (a).
It is a Xb line sectional view.

11A and 11B show the valve operating mechanism, FIG. 11A is a cross-sectional view of the intake / exhaust valve at the time of pause switching, and FIG.
It is a b line sectional view.

FIG. 12 is a sectional view showing the valve operating mechanism, in which (a) is a sectional view of the intake and exhaust valves at rest, and (b) is XIIb-XII in (a).
It is a b line sectional view.

FIG. 13 is a plan view of a modified example (1) of the 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 the mounting structure thereof.

FIG. 16 shows a modified example (4) of the return spring or its mounting structure, (a) is a plan view and (b) is a partial cross-sectional view.

FIG. 17 shows a modified example (5) of the return spring or its mounting structure, (a) is a plan view and (b) is a partial sectional view.

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

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 modification (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 the mounting structure thereof.

FIG. 22 is a cross-sectional view showing a valve mechanism of a conventional example.

FIG. 23 is a main-portion cross-sectional view showing the valve mechanism in another cutting direction.

FIG. 24 is a cross-sectional view of essential parts showing a modified example of the valve mechanism of the conventional example.

[Explanation of symbols]

1 Cylinder Head 2 Lifter Guide Hole 6 Intake / Exhaust Valve 11 Lifter 12 End Wall 14 Second Entry Hole 16 Lifter Communication Hole 17 Shim 18 Third Entry Hole 19 Cam 20 Piston Guide 22 Cylinder Groove 23 Return Spring Mounting Groove 26 Piston Guide Communication Hole 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 Working Lifter Communication Hole 104 Resting Lifter Communication Hole 111, 112, 118, 119, 120 Return spring 203 Working pressure chamber 204 Resting pressure chamber 206 Working piston guide communication hole 208 Resting piston guide communication hole

Claims (10)

[Claims] 1. An inverted cup-shaped lifter that is slidably inserted into a lifter guide hole of a cylinder head to transmit a cam action of a cam to an intake / exhaust valve, and an axial direction of the intake / exhaust valve inside the lifter. And a piston that reciprocates in a direction substantially orthogonal to the piston, the piston is provided with a first entrance hole into which the stem end of the intake and exhaust valve can enter, and the end wall of the lifter enters the first entrance hole. A valve operating mechanism with a pause mechanism for an internal combustion engine, characterized in that a second entry hole through which the stem end part that has passed through is continuously provided. 2. The valve mechanism with a pause mechanism for an internal combustion engine according to claim 1, wherein the piston is formed in a thin plate shape. 3. A substantially circular disc-shaped piston guide is provided with a cylinder groove on one surface thereof, 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 cylinder 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. The valve operating mechanism with a pause mechanism for an internal combustion engine according to claim 2, wherein an oil passage provided in a lifter and communicating with the lifter communication hole is provided in the cylinder head. 4. A return spring mounting groove is provided in an end portion of a cylinder groove of the piston guide, a short return spring is fitted in the return spring mounting groove, and the return spring mounts the piston in one direction. The valve mechanism with a pause mechanism for an internal combustion engine according to claim 3, wherein the valve mechanism is urged. 5. A shim is attached to an end wall of the lifter, and the shim is provided with a third entrance hole through which the stem end part that has entered the second entrance hole can subsequently enter. The valve operating mechanism with a pause mechanism for an internal combustion engine according to claim 1. 6. The operation mechanism with a stop mechanism for an internal combustion engine according to claim 1, wherein the cam is provided with an entrance groove into which the stem end part that has entered the second entrance hole can enter. Valve mechanism. 7. The internal combustion engine-equipped motion mechanism according to claim 5, wherein the cam is provided with an entrance groove into which the stem end part, which has passed through the third entrance hole, can subsequently enter. Valve mechanism. 8. An operating pressure chamber is formed between one end surface of the piston and a piston guide, and a resting pressure chamber is formed between the other end surface of the piston and the piston guide. And a suspension piston guide communication hole for supplying engine oil to the suspension pressure chamber and a suspension piston guide communication hole, 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 operating lifter communicating hole and a resting lifter communicating hole are provided in the lifter, and an operating oil passage and a resting oil passage communicating with the operating lifter communicating hole and the resting lifter communicating hole are provided in the cylinder head. The valve operating mechanism with a pause mechanism for an internal combustion engine according to claim 3, 4, or 5. 9. The operating lifter communicating hole and the resting lifter communicating hole, and the operating oil passage and the resting oil passage,
9. The valve operating mechanism with a pause mechanism for an internal combustion engine according to claim 8, wherein the valve 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 pause mechanism for an internal combustion engine according to claim 4, further comprising disengagement prevention means for stopping the return spring in the return spring mounting groove.