JPH07305610A - Intake/exhaust valve structure for internal combustion engine - Google Patents

Abstract

PURPOSE:To secure smooth motion of an intake/exhaust valve by securing smooth motion of each stem irrespective of manufacturing error. CONSTITUTION:An aperture 4 of an intake port 3 communicated with a combustion chamber 2 is opened and closed by an intake valve 6. The aperture 4 has an oval shape. The intake valve 6 has a valve shade 8 which can open and close the aperture 4 and a pair of stems 9, 10 extending from the valve shade 8 parallely to each other. The valve shade 8 is integrated with the stems 9, 10, and can be divided into two valve pieces 18, 19 between the stems 9 and 10. Abutting surfaces 18a, 19a of the valve pieces 18, 19 are engaged with each other. The stems 9, 10 are supported slidably to a cylinder head 1 through stem guides 11, 12. Manufacturing error in the intake valve is eliminated between the valve piece 18 and 19. Arrangement of the stems 9, 10 is aligned in their moving directions.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intake / exhaust valve that operates for intake / exhaust in a combustion chamber of an internal combustion engine, and more particularly to an intake / exhaust valve structure thereof.

[0002]

2. Description of the Related Art Conventionally, it has been considered to increase the number of intake and exhaust valves provided for a combustion chamber in order to increase the output of an internal combustion engine. That is, the number of intake / exhaust ports in the combustion chamber is increased, and the number of intake / exhaust valves is increased accordingly. With this configuration, the passage area for intake and exhaust is increased to increase intake and exhaust efficiency.

However, in the above structure, since the valve diameter of the intake / exhaust valve must be secured to some extent for each opening of each port, the substantial passage area obtained by all the openings does not become so large. Moreover, the air-fuel mixture flowing into the combustion chamber through the openings of the intake ports tends to interfere with each other. Therefore, even if the passage areas obtained by all the openings are made to have a certain size or more, it is difficult for the amount of increase in intake air to be larger than the increase in the area. This also applies to the exhaust gas, and there is a tendency that the intake / exhaust efficiency of the combustion chamber as a whole does not improve so much.

Therefore, Japanese Utility Model Laid-Open No. 60-107306 discloses an intake valve structure intended to improve the intake / exhaust efficiency by substantially improving the intake / exhaust efficiency in response to the above problems.

As shown in FIG. 37, in this intake valve structure, in order to improve intake efficiency, an opening 53 for the combustion chamber 52 of the intake port 51 is formed in an oval shape, and
The valve head portion 5 of the intake valve 54 according to the shape of the opening 53.
5 is formed in an oval shape. Two stems 56 and 57 are integrally formed on the valve head portion 55, and these stems 56 and 57 are slidably attached to the cylinder head 60 via stem guides 58 and 59.
Both stems 56 and 57 have retainers 61 at their upper ends.
It is pressed by a cam (not shown) via the above. By this pressing, the valve umbrella portion 55 is pushed down and the opening portion 53 is opened.

[0006]

By the way, in the above intake valve 54, both stems 56 and 57 need to be formed in parallel with each other in the same length in order to ensure the smooth operation thereof. Similarly, both stem guides 58, 59 need to be arranged in parallel with each other in the cylinder head 60. However, the intake valve 54 and both stem guides 5
If there is some manufacturing error in 8, 59, or the cylinder head 60, etc., the positions of both stems 56, 57 are aligned with the positions of both stem guides 58, 59 due to such errors. May not. In this case, the movement of both the stems 56 and 57 when pressed by the cam becomes poor, and there is a possibility that the smooth operation of the intake valve 54 may be hindered. Alternatively, if the stems 56, 57 are slightly different in length, one of the stems 56, 57 will be pressed before the other. As a result, both stems 5
Unreasonable bending stress may be generated between the valves 6, 57 and the valve head portion 55, and smooth operation of the intake valve 54 may be hindered.

The present invention has been made in view of the above-mentioned circumstances, and a first object thereof is to ensure smooth movement of each stem regardless of some manufacturing errors and the like, so that the intake and exhaust valves can be operated smoothly. It is an object of the present invention to provide an intake / exhaust valve structure for an internal combustion engine that can ensure a smooth operation.

A second object of the present invention is to provide an intake / exhaust valve structure for an internal combustion engine which can secure good airtightness of the intake / exhaust valve.

[0009]

In order to achieve the first object, in the first aspect of the present invention, an intake / exhaust valve for opening / closing an opening of an intake / exhaust port communicating with a combustion chamber is provided. In an intake / exhaust valve structure for an internal combustion engine having a valve head portion capable of opening and closing an opening and a plurality of stems extending from the valve head portion, each stem is formed integrally with the valve head portion, and It is intended that the umbrella portion is formed so as to be divided into a plurality of valve pieces between the stems.

In order to achieve the above first object, in a second aspect of the present invention, an intake / exhaust valve for opening / closing an opening of an intake / exhaust port communicating with a combustion chamber is provided. In an intake / exhaust valve structure of an internal combustion engine having an openable / closable valve head portion and a plurality of stems extending from the valve head portion, at least one stem and the valve head portion are separately formed and assembled. It is intended.

In order to achieve the first and second objects, in the third invention according to claim 3, in the structure of the first invention, a part of the valve pieces adjacent to each other is vertically stacked. It is intended that the overlapped lower valve piece is configured to be opened earlier and closed later than the upper valve piece.

In order to achieve the above-mentioned second object, in the fourth invention described in claim 4, the first, second or third invention is provided.
In the configuration of the invention described above, it is intended that a flexible sealing material is interposed between the divided valve pieces or between the valve head portion and the stem.

[0013]

According to the first aspect of the invention, the stems are simultaneously moved in the axial direction of the intake and exhaust valves in the state where the intake and exhaust valves are assembled to the internal combustion engine, and the entire valve head portion is integrally moved. Thereby, the opening of the intake / exhaust port leading to the combustion chamber is opened / closed. Here, even if there are some manufacturing errors in the intake and exhaust valves and the like, the errors and the like will be released between the valve pieces, and the arrangement of the stems will match their moving directions.

According to the second aspect of the invention, even if there is some manufacturing error in the intake / exhaust valve or the like, the error is released between the valve stem portion and the separate stem. Becomes
The placement of each stem matches its direction of travel.

According to the third aspect of the invention, even if there is some manufacturing error in the intake / exhaust valve or the like, the error will be released between the valve pieces, and the arrangement of the stems will be improved. Match their movement direction. In addition, since the adjacent valve pieces are partially overlapped with each other, the valve pieces are sealed with a large contact area.

According to the structure of the fourth invention, in the structure of the first or third invention, the space between the valve pieces is sealed by a flexible seal material. In the configuration of the second invention, the space between the valve head portion and the separate stem is sealed with a flexible seal material.

[0017]

【Example】

(First Embodiment) A first embodiment in which the intake / exhaust valve structure for an internal combustion engine according to the first invention is embodied as an intake valve structure will now be described with reference to FIG.
~ It will be described in detail with reference to FIG.

FIG. 1 is a perspective view showing the intake valve structure in this embodiment with a part broken away, and FIG. 2 is a vertical sectional view showing the structure. 3 is a front view showing a part of the intake valve, FIG. 4 is a bottom view of the intake valve, and FIG. 5 is a view of the opening of the intake port and the like as seen from the combustion chamber side.

The reciprocating type internal combustion engine is provided with a cylinder head 1, and an intake port 3 communicating with a combustion chamber 2 of each cylinder is formed in the head 1. This intake port 3
The opening 4 for the combustion chamber 2 is formed in an elliptical shape having a passage area larger than that of a normal circular shape in order to enhance the intake efficiency in the combustion chamber 2. A valve seat 5 is attached around the opening 4. As shown in FIG. 2, the intake port 3 extends almost straight toward the combustion chamber 2,
The inclination is set to be close to the inclination of the bottom wall 1a around the exhaust valve (not shown) in the combustion chamber 2. With this configuration, the step between the bottom wall around the intake valve 6 and the bottom wall around the exhaust valve is made as small as possible. As shown in FIG.
A spark plug 7 is provided in the cylinder head 1 adjacent to the opening 4.
Is attached. This spark plug 7 has an opening 4
Is arranged corresponding to the center of the longitudinal direction.

The intake valve 6 comprises a valve head portion 8 and two stems 9 and 10 extending upward from the upper surface of the valve head portion 8 in parallel. The valve umbrella portion 8 is for seating on the valve seat 5 to close the opening portion 4, and is formed in an oval shape in accordance with the opening portion 4. This shape is different from an intake valve having a normal circular valve head portion. Both stems 9 and 10 are slidably attached to the cylinder head 1 via cylindrical stem guides 11 and 12. As shown in FIG. 2, the upper ends of both the stems 9 and 10 can be separately pressed by different cams 16 via a retainer 13, a lifter 14, a shim 15 and the like. The profiles of these two cams 16 and their rotational phases are set to be the same. Further, a spring 17 is interposed between the cylinder block 1 and the retainer 13, and the spring 17 constantly urges the intake valve 6 in the direction of closing the opening 4 (upward). The configurations of both the stems 9 and 10 and the members 13 to 17 related thereto are the same as those of a normal intake valve.

In the intake valve 6, both stems 9 and 10 and the valve head portion 8 are integrally formed. The valve head portion 8 is formed so as to be divided into two valve pieces 18 and 19 in the middle of both the stems 9 and 10. As shown in FIGS. 1, 3 and 6, recesses 18b and protrusions 19b extending in the width direction of the valve head portion 8 are formed on the mating surfaces 18a and 19a of the valve pieces 18 and 19, respectively. It is fitted. Figure 6
As shown in FIG. 7, a slight gap G is formed in advance between the concave line 18b and the convex line 19b in order to allow a slight positional deviation between the valve pieces 18 and 19.

In this embodiment, an exhaust port (not shown) communicating with the combustion chamber 2 is formed in the cylinder head 1, and an exhaust valve is openably and closably arranged at the opening of the exhaust port. This exhaust valve has a normal circular valve head portion, and is driven via a cam or the like (not shown) like the intake valve 6. The intake valve 6 and the exhaust valve are driven in synchronization with the rotation cycle of the output shaft of the internal combustion engine, and a mixture of fuel and air is introduced into the intake port 3. These are well known in the art.

Next, the operation and effect of the intake valve structure configured as described above will be described. In the intake stroke of the internal combustion engine, when the stems 9 and 10 are pressed downward by the action of the cam 16 and move, the entire valve head portion 8 is integrally separated from the valve seat 5 as shown in FIG. The opening 4 leading to the combustion chamber 2 is opened. Here, since the opening 4 is an ellipse having a relatively large area, a large amount of air-fuel mixture is taken into the combustion chamber 2 through the intake port 3 without causing flow interference, and The intake efficiency can be improved.

Moreover, when the opening 4 is opened, there is nothing in the vicinity of the center of the opening 4 which serves as a resistance to intake air. Neither of the stems 9 and 10 is located near the center of the opening 4. Therefore, the flow of the air-fuel mixture is likely to concentrate near the center of the combustion chamber 2, the air-fuel mixture convects in the axial direction of the combustion chamber 2, and an axial vortex (longitudinal vortex) is formed. After that, when the spark plug 7 operates near the top dead center of the compression stroke of the internal combustion engine, the air-fuel mixture burns. At this time,
Since the vertical vortex flow as described above is given to the air-fuel mixture, stratified combustion in the left-right (radial) direction of the combustion chamber 2 can be obtained. Then, due to the stratified combustion and the turbulence of the mixed air flow, it is possible to easily achieve lean combustion.

Further, in this embodiment, since the intake valve 6 is supported by the cylinder head 1 by the two stems 9 and 10, there is no possibility that the intake valve 6 will be rotationally displaced around its axis. Therefore, opening / closing of the opening 4 by the intake valve 6 can be stabilized.

Moreover, in this embodiment, the valve head portion 8 is composed of two separable valve pieces 18 and 19, and their mating surfaces 18a and 19a are fitted in a concave-convex relationship, and a gap G is provided between them. Are formed. Therefore, even if there is a slight manufacturing error in the intake valve 6 or the like, the error is released between the valve pieces 18 and 19, and the arrangements of the stems 9 and 10 are aligned with their moving directions. . The same applies even if the intake valve 6 is slightly deformed.

For example, even if there is an error between the arrangement of the stems 9 and 10 and the arrangement of the stem guides 11 and 12 due to a manufacturing error of the intake valve 6 or the cylinder head 1, etc., the intake valve 6 Is attached to the cylinder head 1, so that the clearance G between the stems 9 and 10 is absorbed by the gap G between the valve pieces 18 and 19.

Alternatively, even if the lengths of the stems 9 and 10 are precisely different, the difference is absorbed by the gap G between the valve pieces 18 and 19. Therefore, each stem 9, 10
The distances between the upper ends of the stems and their corresponding cams 16 are the same, and both stems 9 and 10 are pressed simultaneously by the cams 16. As a result, an unreasonable bending stress is not generated between the stems 9 and 10 and the valve head portion 8,
The parallelism of 10 does not collapse. As a result, the intake valve 6
Both stems 9 and 1 regardless of some manufacturing errors related to
A smooth movement of 0 can be ensured, and a smooth operation of the intake valve 6 can be ensured.

In this embodiment, since the mating surfaces 18a and 19a of the two valve pieces 18 and 19 are fitted in a concavo-convex relationship, the airtightness between the two valve pieces 18 and 19 can be secured.

Furthermore, in this embodiment, although the shape and size of the valve head portion 8 are different from those of a normal intake valve, both stems 9 and 1 are
The size of 0 and each of the members 13 to 17 associated therewith are the same as the normal one. Therefore, when assembling the intake valve 6 of this embodiment to the cylinder block 1, the members 13 to 1 are
It is possible to share 7 with that of a normal intake valve.
Therefore, the production line for assembling the ordinary intake valve can be shared for assembling the intake valve 6 of this embodiment. That is, there is no need to provide a separate manufacturing line for assembling the intake valve 6 of this embodiment.

(Second Embodiment) Next, a second embodiment in which the intake / exhaust valve structure for an internal combustion engine according to the fourth invention is embodied as an intake valve structure.
An embodiment will be described with reference to FIGS.

7 and 8 are drawings based on FIGS. 1 and 2 described above. 9 shows a cross-sectional shape of the intake port 3, and FIG.
FIG. 4 is an enlarged sectional view showing a central portion of a valve head portion 8.
In each of the following embodiments including this embodiment, the same components as those in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted. Differences will be mainly described.

The intake valve 20 of this embodiment differs from the intake valve 6 in the shape of the valve head portion 8. That is,
As shown in FIGS. 7 and 8, the central portion of the valve head portion 8 has a substantially triangular cross-sectional shape, and the upper surface 8a near the central portion.
Are inclined toward the combustion chamber 2 along the direction of the air-fuel mixture flow. Further, in this embodiment, as shown in FIG. 9, the intake port 3 has a trapezoidal cross-sectional shape in which the upper bottom is longer than the lower bottom.

In addition, in this embodiment, as shown in FIG. 10, the mating surfaces 18a of the split valve pieces 18 and 19 are
A flexible sealing material 21 is interposed in the entire area between 19a. This sealing material 21 is used for both valve pieces 18, 19
Join between them with some flexibility. As the sealing material 21, a simple substance of a flexible metal such as copper, zinc, lead, indium or tin, or an alloy of lead and tin,
An alloy formed by appropriately mixing the above metals can be used.

Therefore, in this embodiment, as shown in FIG. 8, the air-fuel mixture flow (indicated by the arrow) when the opening 4 is opened is further increased along the inclination of the upper surface 8a of the valve head portion 8. It is smoothly guided to the combustion chamber 2, and the generation of the vertical vortex flow in the combustion chamber 2 can be further promoted. In that sense, stratified combustion of the air-fuel mixture, and further lean combustion, can be further promoted.

In addition, in this embodiment, since the cross section of the intake port 3 has a broad trapezoidal shape on the upper side, the flow of the air-fuel mixture is concentrated in the upper layer of the intake port 3. As a result, in combination with the shape of the valve head portion 8, the air-fuel mixture is mixed with the combustion chamber 2
Can be concentrated in the center of the spark plug 7, and can be concentrated in the vicinity of the spark plug 7. From this point of view, the generation of the vertical vortex flow can be further promoted, and by extension, the leanness limit of the fuel in the air-fuel mixture for performing lean combustion can be expanded.

Further, in this embodiment, both valve pieces 18, 19 are
A sealing material 21 seals between the mating surfaces 18a and 19a. Then, in this sealed state, both valve pieces 18, 1
Since 9 is joined with moderate flexibility, both 1
Some relative movement is allowed between 8 and 19. Therefore, similar to the first embodiment, it is possible to allow a slight manufacturing error or the like related to the intake valve structure to ensure smooth movement of both the stems 9 and 10, and to ensure smooth operation of the intake valve 20. Can be secured. At the same time, when the opening 4 is closed by the intake valve 20, the airtightness between the valve pieces 18 and 19 can be enhanced by the sealing material 21, and the good airtightness of the intake valve 20 can be further secured. It can be effectively achieved.

(Third Embodiment) Next, a third embodiment in which the intake / exhaust valve structure for an internal combustion engine according to the second invention is embodied as an intake valve structure.
An embodiment will be described with reference to FIG.

FIG. 11 is a partially cutaway front view of the intake valve 22 in this embodiment. The intake valve 22 differs from the intake valves 6 and 20 in the structure of the valve head portion 23 and the pair of stems 24 and 25. That is, unlike the valve head portion 8 described above, the valve head portion 23 is not divided and is integrally formed in an oval shape. Both stems 24, 25
Extend upward from the valve head portion 23 in parallel with each other, one stem 24 is formed integrally with the valve head portion 23, and the other stem 25 is formed separately from the valve head portion 23. And
The separate stem 25 is assembled to the valve head portion 23. The separate stem 25 has a round bar shape, and a flange 25a is formed near the lower end thereof. The valve head portion 23 has a hole 26 through which the stem 25 is assembled and which is vertically penetrated.
Are formed. The inner diameter of this hole 26 has two steps, and the wide mouth portion 2 in which the lower surface side of the valve head portion 23 is larger than the upper surface side thereof.
6a. Then, the lower end of the stem 25 is inserted into the hole 26 from the upper surface side of the valve head portion 23, and is welded to the stopper plate 27 fitted in the wide mouth portion 26a. The lower end of the stem 25 is positioned on the valve head portion 23 between the stopper plate 27 and the flange 25a. In this state, stem 2
A slight gap is formed between the hole 5 and the hole 5 in order to allow a slight positional deviation between the holes 25 and 26.

Therefore, even if there is some manufacturing error in the intake valve 22 and the like of this embodiment, the error is released between the valve head portion 23 and the stem 25 in the assembled state with the cylinder head. Both stems 24 and 2
The arrangement of 5 matches the direction of their movement. As a result, the smooth movement of both the stems 24 and 25 can be ensured regardless of some manufacturing error, and the smooth operation of the intake valve 22 can be ensured. In addition, the operation and effect obtained by the shape of the valve head portion 23 are basically the same as those of the first embodiment.

(Fourth Embodiment) Next, a fourth embodiment in which the intake / exhaust valve structure for an internal combustion engine according to the second invention is embodied as an intake valve structure.
An example will be described with reference to FIG.

FIG. 12 is a front view showing a partially cutaway view of the intake valve 28 in this embodiment. The intake valve 28 is slightly different from the intake valve 22 of the third embodiment in the structure of attaching a separate stem 29 to the valve head portion 23. That is, the lower end of the separate stem 29 is a spherical journal 30. On the other hand, in order to assemble the journal 30, a spherical concave portion 31 is formed on the upper surface of the valve head portion 23. The lower half of the journal 30 is fitted into the recess 31 of the valve head portion 23, and the periphery of the upper half of the journal 30 is welded to the upper surface of the valve head portion 23.
Covered by 2. With such a spherical bearing structure, the lower end of the stem 29 is assembled to the valve head portion 23, and the stem 29 has the valve head portion 2 centered around the journal 30.
3 can be tilted to some extent in any direction.

Therefore, even if the intake valve 28 of this embodiment has some manufacturing error, the error is released between the valve head 23 and the stem 29 as in the third embodiment. , The arrangement of both stems 24, 29 is aligned with their direction of movement. As a result, even in this intake valve structure, the third
The same operation and effect as those of the embodiment can be obtained.

(Fifth Embodiment) Next, a fifth embodiment in which the intake / exhaust valve structure for an internal combustion engine according to the third invention is embodied as an intake valve structure.
An example will be described with reference to FIG.

FIG. 13 is a partially cutaway front view of the intake valve structure in this embodiment. The intake valve 33 of this embodiment includes a valve head portion 8 that can be divided into two valve pieces 18 and 19 as in the first and second embodiments. Further, the stems 9 and 10 are integrally formed with the valve pieces 18 and 19, respectively. In this embodiment, both valve pieces 18,
The mating surfaces 18a, 19a of 19 are obliquely cut in the same direction. The mating surface 19a of the other valve piece 19 is superposed on the mating surface 18a of the one valve piece 18. Further, in this embodiment, the stems 9 and 10 are
Corresponding to, retainer 13, lifter 14, shim 15A,
15B, the cam 16 and the spring 17 are assembled in the same manner as in the first and second embodiments.

Here, in the valve head portion 8, the lower valve piece 18 opens before the upper valve piece 19 and closes later. As a configuration for that, the thickness of the shim 15A corresponding to the lower valve piece 18 is set to be larger than that of the upper valve piece 19. That is, by changing the thickness of each shim 15A, 15B, a difference is provided between the clearances C1, C2 with respect to each cam 16. In FIG. 13, both clearances C1 and C2 are exaggerated and shown in a large size, but they are actually in units of microns.

Therefore, also in this embodiment, even if there is some manufacturing error in the intake valve 33 or the like, the error will be released between the valve pieces 18 and 19, and the stems 9 and 10 will be released. The arrangements of are aligned with their moving directions. As a result, smooth movement of both stems 9 and 10 can be ensured regardless of some manufacturing error, and smooth operation of intake valve 33 can be ensured.

In addition, since the mating surfaces 18a and 19a of the two adjacent valve pieces 18 and 19 are vertically overlapped with each other, the space between the two valve pieces 18 and 19 is sealed by a corresponding amount. become. As a result, when the opening is closed by the intake valve 33, the airtightness between the valve pieces 18 and 19 can be enhanced, and the good airtightness of the intake valve 33 can be ensured.

In addition, the operation and effect obtained by the shape of the valve head portion 8 are basically the same as those of the first embodiment. Further, in the structure of this embodiment, it is possible to open only the lower valve piece 18 while keeping the upper valve piece 19 closed. Therefore, by configuring the movement of each cam 16 corresponding to each stem 9 and 10 to be individually controllable, the opening of the intake port can be fully opened or half opened.

(Sixth Embodiment) Next, a sixth embodiment in which the intake / exhaust valve structure for an internal combustion engine according to the first invention is embodied as an intake valve structure.
An example will be described with reference to FIGS. The drawings referred to in each of the following embodiments including this embodiment are based on FIGS. 3 to 5 of the first embodiment.

In this embodiment, the intake valve structure of the first embodiment is modified in shape. In this embodiment, the valve head portion 8 has an elliptical shape and accordingly the opening 4
Has an elliptical shape. The other structure is the same as that of the first embodiment. Therefore, also in this embodiment, the first
The same operation and effect as those of the embodiment can be obtained.

(Seventh Embodiment) Hereinafter, a seventh embodiment in which the intake / exhaust valve structure of the internal combustion engine according to the first invention is embodied as an intake valve structure.
An example will be described with reference to FIGS.

Also in this embodiment, the shape of the intake valve structure of the first embodiment is changed. In this embodiment, two valve pieces 18 and 19 in which the valve head portion 8 has a substantially elliptical shape.
Has a shape in which a part of “” is overlapped in a “C” shape, and the opening 4 has a shape adapted to the valve head portion 8. Both valve pieces 18, 1
The nine mating surfaces 18a and 19a are vertical flat surfaces. The other structure is the same as that of the first embodiment. Therefore, also in this embodiment, the same operation and effect as those of the first embodiment can be obtained.

In addition, in this embodiment, both valve pieces 18,
Since the mating surfaces 18a, 19a of 19 are flat surfaces in the vertical direction, it is possible to open only one of the mating surfaces 18, 19. Therefore, it is possible in structure to open the opening 4 fully or half.

(Eighth Embodiment) Next, the intake / exhaust valve structure of the internal combustion engine according to the first invention is embodied as an intake valve structure.
An example will be described with reference to FIGS.

This embodiment also shows a modification to the intake valve structure of the first embodiment. In this example,
The valve head portion 8 has a shape in which two valve pieces 18 and 19 having a substantially circular shape are partially overlapped with each other, and the opening 4 has a shape that matches the valve head portion 8. Mating surfaces 18a of both valve pieces 18, 19
19a is a flat surface in the vertical direction. However,
Regarding the shapes of the two valve pieces 18 and 19, it is considered that both the valves 18 and 19 are symmetrical with respect to each other as shown in FIG. 21 and the both 18 and 19 are asymmetric with respect to each other as shown in FIG. The other structure is the same as that of the first embodiment. Therefore, also in this embodiment, it is possible to obtain the same actions and effects as those in the first embodiment.

Besides, in this embodiment, like the seventh embodiment, only one of the valve pieces 18 and 19 can be opened, and the opening 4 can be fully opened or half opened. It is possible due to the configuration.

(Ninth Embodiment) Next, the intake / exhaust valve structure of the internal combustion engine according to the first invention is embodied as an intake valve structure.
An example will be described with reference to FIGS.

This embodiment also shows a modification to the intake valve structure of the first embodiment. In this example,
Unlike the first embodiment and the like, the valve head portion 39 has three valve pieces 40,
It is composed of 41 and 42. That is, the valve head 39
Is divided into three parts. Each of the valve pieces 40 to 42 has a substantially circular shape, and the valve pieces 40 to 42 are arranged in series and a part of the valve pieces 40 to 42 adjacent to each other are stacked. Further, the stems 43, 44 and 45 which are parallel to each other are integrally formed on the valve pieces 40 to 42, respectively. These stems 43 to 45 are supported by the cylinder head 1 via stem guides 46, 47 and 48. The opening 4 has a shape that matches the valve head 39. The other structure is the same as that of the first embodiment. Therefore, also in this embodiment, the same operation and effect as those of the first embodiment can be obtained.

(Tenth Embodiment) Next, a tenth embodiment in which the intake / exhaust valve structure for an internal combustion engine according to the first invention is embodied as an intake valve structure will be described with reference to FIG.

This embodiment shows a modification of the intake valve structure of the first embodiment. In the intake valve structure of this embodiment, compared with that of the first embodiment, both stem guides 11,
The shapes of 12 are different. That is, both stems 11 and 12
The portions exposed to the intake port 3 are blades 11a and 12a having a streamline shape parallel to the flow of the air-fuel mixture. Both wings 11a, 12a are arranged parallel to each other. The other structure is the same as that of the first embodiment.

Therefore, also in this embodiment, the same operation and effect as in the first embodiment can be obtained. In addition, since the portions of both the stem guides 11 and 12 exposed to the intake port 3 are streamlined blades 11a and 12a, the flow passage resistance in the intake port 3 is reduced. As a result, the intake and exhaust efficiency in the combustion chamber 2 can be improved, and the generation of the vertical vortex flow in the combustion chamber 2 can be further promoted. In that sense, stratified combustion of the air-fuel mixture, and further lean combustion, can be further promoted.

Further, the gist of the intake valve structure of this embodiment can be embodied in the second to ninth embodiments. (Eleventh Embodiment) Next, an eleventh embodiment in which the intake / exhaust valve structure for an internal combustion engine according to the first invention is embodied as an intake valve structure will be described with reference to FIG.

This embodiment shows a modification of the intake valve structure of the first embodiment. In the intake valve structure of this embodiment, the shape of the valve head portion 8 is different from that of the first embodiment. That is, both valve pieces 18 and 19 that form the valve umbrella portion 8
A pair of deflecting plates 18c, 19 standing upright on the upper surface of the
c is formed. Both the deflection plates 18c and 19c are arranged in a V shape in the flow direction of the air-fuel mixture.
A central axis line between 8c and 19c is arranged toward the center of the combustion chamber 2. The other structure is the same as that of the first embodiment.

Therefore, also in this embodiment, the same operation and effect as in the first embodiment can be obtained. In addition, the intake valve 6
When the valve is opened, the flow of the air-fuel mixture is changed by the deflection plates 18c and 19c on the upper surfaces of the valve pieces 18 and 19, respectively.
Will be concentrated on the central part of. as a result,
It is possible to further promote the generation of the vertical vortex flow in the central portion of the combustion chamber 2. In that sense, stratified combustion of air-fuel mixture,
As a result, lean combustion can be further promoted.

The gist of the intake valve structure of this embodiment can be embodied in the second to ninth embodiments. (Twelfth Embodiment) Next, a twelfth embodiment in which the intake / exhaust valve structure for an internal combustion engine according to the first invention is embodied as an intake valve structure will be described with reference to FIGS.

This embodiment shows a modification of the intake valve structure of the first embodiment. In the intake valve structure of this embodiment, compared with that of the first embodiment, both stem guides 11,
The shapes of 12 are different. That is, as shown in FIGS. 29 and 30, the portions of both the stems 11 and 12 exposed to the intake port 3 form a streamlined shape parallel to the flow of the air-fuel mixture, and have blades 11b and 12b having a trapezoidal side surface shape. Has become. Both blades 11b and 12b are arranged in a V-shape in the flow direction of the air-fuel mixture, and the central axis line between the two blades 11b and 12b is arranged toward the center of the combustion chamber 2. The other structure is the same as that of the first embodiment.

Therefore, also in this embodiment, the same operation and effect as those of the first embodiment can be obtained. In addition, the intake valve 6
Wing 11 of both stem guides 11 and 12 when is opened
By b and 12b, the flow of the air-fuel mixture is concentrated and directed to the central portion of the combustion chamber 2, as shown by the arrow in FIG. As a result, the generation of the vertical vortex flow in the central portion of the combustion chamber 2 can be further promoted. In that sense, stratified combustion of the air-fuel mixture, and further lean combustion, can be further promoted.

Alternatively, as a modification of this embodiment, FIG.
As shown in FIG. 1, the wings 11b and 12b are parallel to each other,
In addition, they are arranged so that their directions deviate from the center of the combustion chamber 2. In this case, the flow of the air-fuel mixture is the combustion chamber 2
Since it will be concentrated on one side portion, it is possible to further promote the generation of the vertical vortex flow on the one side portion. In that sense, stratified combustion of the air-fuel mixture, and further lean combustion, can be further promoted.

The gist of the intake valve structure of this embodiment can be embodied in the second to ninth embodiments. The present invention can be embodied in the following other embodiments.

(1) In the second embodiment, both valve pieces 18,
The sealing material 2 is provided in the entire area between the mating surfaces 18a, 19a
1 was interposed. On the other hand, as shown in FIG. 32, the sealing material 21 is interposed only between the concave stripes 18b and the convex stripes 19b, or as shown in FIG.
The sealing material 21 may be interposed only on the upper side of 9a. In these cases, the airtightness is slightly inferior to that of the second embodiment, but it is advantageous in that the amount of the sealing material 21 used can be reduced.

(2) In the fifth embodiment, both valve pieces 18,
Although 19 mating surfaces 18a and 19a are directly superposed on each other, in the configuration of the fifth embodiment, as shown in FIG. 34, a sealing material 21 may be interposed between the mating surfaces 18a and 19a. . In this case, in the configuration of the fifth embodiment, the airtightness of the intake valve 33 can be improved.

(3) In the fifth embodiment, both valve pieces 18,
Although the mating surfaces 18a, 19a of 19 are flat surfaces cut obliquely, as shown in FIG.
You may cut | disconnect 9a in a step shape and may be piled up on top of each other. In this case as well, since the space between the two valve pieces 18 and 19 is sealed with a larger contact area, good airtightness of the intake valve 33 can be ensured.

(4) In the third and fourth embodiments, of the two stems 24, 25, or both the stems 24, 29,
Only one of the stems 25 and 29 was formed separately from the valve head portion 23 and assembled together. On the other hand, both of the two stems may be formed separately from the valve head portion and assembled together.

(5) In the fifth embodiment, in order to open the lower valve piece 18 that is vertically stacked and open the upper valve piece 19 earlier than the upper valve piece 19, both shims 15A,
There was a difference in the thickness of 15B. On the other hand, both valve pieces 1
8 and 19, the two lifters 14 corresponding to each other have different heights, and the two cams 1 corresponding to both valve pieces 18 and 19 are provided.
The profile characteristics may be different among the six.

(6) In each of the above embodiments, the intake / exhaust valve structure is embodied only in the intake valve, but it may be embodied only in the exhaust valve or in both the intake valve and the exhaust valve.

(7) In the second embodiment, in the structure embodying the first invention, the intake port 3 has a trapezoidal cross-sectional shape that expands upward, and the upper surface 8a of the valve head 8 is connected to the combustion chamber 2. A tilt angle is applied.

On the other hand, either the shape limitation of the intake port or the shape limitation of the valve head portion as described above may be adopted. Alternatively, in the configuration in which the second or third invention is embodied, at least one of the shape limitation of the intake port and the shape limitation of the valve head portion as described above may be adopted. In these cases, the same operation and effect as those of the second embodiment can be obtained.

(8) As for the positional relationship of both stems with respect to the valve head portion, as shown in FIG. 36, the two stems 9 and 10 are as far as possible on both sides of the upper surface of the valve head portion 8 as compared with those of the above-mentioned embodiments. Place them close together. With this configuration, the flow path resistance near the opening 4 can be further reduced, and the intake / exhaust efficiency can be improved.

Although the respective embodiments of the present invention have been described above, it is stated that the respective embodiments include the following various embodiments relating to the technical idea described in the scope of claims. The effect is described in.

(A) In claim 1, an intake / exhaust valve structure for an internal combustion engine in which the mating surfaces of the valve pieces constituting the valve head portion are fitted to each other in a concavo-convex relationship, and a slight gap is formed between them. .

According to this structure, in addition to the effect of the structure of claim 1, the airtightness between the valve pieces can be enhanced and the airtightness of the intake valve can be secured. (B) An intake / exhaust valve structure for an internal combustion engine as defined in claim 1, claim 2 or claim 3, wherein the intake / exhaust port has a broad trapezoidal sectional shape on the upper side.

According to this structure, in addition to the effects of the first, second or third structure, the intake / exhaust flow in the intake / exhaust port can be concentrated in the center of the opening.

(C) An intake / exhaust valve structure for an internal combustion engine according to claim 1, claim 2 or claim 3, wherein an inclination angle toward the combustion chamber is provided on the upper surface of the valve head portion. According to this structure, in addition to the effects of the structure of claim 1, claim 2 or claim 3, generation of a vertical vortex flow in the combustion chamber can be further promoted, and stratified combustion of the air-fuel mixture is further promoted. Can be made.

(D) In Claim 1, Claim 2 or Claim 3, each stem is movable along the stem guide, and a part of each stem guide is arranged so as to be exposed to the intake port. An intake / exhaust valve structure for an internal combustion engine having a streamlined blade parallel to the intake / exhaust flow on the exposed portion.

According to this construction, in addition to the effects of the construction of claim 1, claim 2 or claim 3, the intake and exhaust efficiency in the combustion chamber can be improved, and the generation of a vertical vortex flow in the combustion chamber. Can be promoted.

(E) An intake / exhaust valve structure for an internal combustion engine according to claim 1, claim 2 or claim 3, wherein a deflection plate for deflecting an intake / exhaust flow is provided on an upper surface of the valve head portion. According to this configuration, in addition to the effects of the configuration of claim 1, claim 2 or claim 3, generation of a vertical vortex flow in the combustion chamber can be promoted.

In this specification, means, members and the like relating to the constitution of the invention are defined as follows. (A) The intake / exhaust valve is a generic term for an intake valve and an exhaust valve, and includes a case where only one of them is meant.

(B) The intake / exhaust port is a generic term for the intake port and the exhaust port, and includes the case where only one of them is meant.

[0090]

As described in detail above, according to the first aspect of the present invention, each stem is formed integrally with the valve head portion, and the valve head portion is provided between the stems. It is divided into valve pieces. Therefore, some manufacturing errors in the intake / exhaust valves and the like are released between the valve pieces, and the arrangement of the stems is aligned with their moving directions. As a result, the smooth movement of each stem can be ensured, and the smooth operation of the intake and exhaust valves can be ensured.

According to the second aspect of the present invention, at least one stem and the valve head portion are separately formed and assembled. Therefore, some manufacturing errors in the intake / exhaust valves and the like are released between the valve head portion and at least one stem, and the arrangement of each stem is aligned with the movement direction thereof. As a result, the smooth movement of each stem can be ensured, and the smooth operation of the intake and exhaust valves can be ensured.

According to the third aspect of the present invention, a part of the adjacent valve pieces are vertically overlapped with each other, and the lower valve piece is opened earlier than the upper valve piece and then closed. Is configured. Therefore, some manufacturing errors in the intake and exhaust valves and the like are released between the valve pieces, and the arrangement of the stems is aligned with their moving directions. In addition, a larger contact area is provided between the valve pieces. As a result, the smooth movement of each stem can be ensured, the smooth operation of the intake and exhaust valves can be ensured, and at the same time, the good airtightness of the intake and exhaust valves can be ensured. Demonstrate.

According to the fourth aspect of the present invention, a flexible sealing material is interposed between the divided valve pieces or between the valve head portion and the stem. Therefore, the space between the valve pieces is sealed with the seal material, or the space between the valve head portion and the separate stem is sealed with the seal material. As a result, it is possible to ensure good airtightness of the intake and exhaust valves.

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view of an intake valve structure in a first embodiment embodying the first invention.

FIG. 2 is a longitudinal sectional view showing an intake valve structure in the first embodiment.

FIG. 3 is a front view showing a part of an intake valve in the first embodiment.

FIG. 4 is a bottom view of the intake valve in the first embodiment.

FIG. 5 is a view of an opening of an intake port and the like seen from a combustion chamber side in the first embodiment.

FIG. 6 is an enlarged sectional view showing mating surfaces of both valve pieces in the first embodiment.

FIG. 7 is a perspective view showing a partially broken view of an intake valve structure in a second embodiment embodying the fourth invention.

FIG. 8 is a vertical sectional view showing an intake valve structure in the second embodiment.

FIG. 9 is a cross-sectional view showing the shape of an intake port in the second embodiment.

FIG. 10 is an enlarged sectional view showing mating surfaces of both valve pieces in the second embodiment.

FIG. 11 is a front view showing a partially cutaway view of an intake valve in a third embodiment of the second invention.

FIG. 12 is a front view showing a partially broken view of a part of an intake valve in a fourth embodiment in which the second invention is embodied.

FIG. 13 is a front view showing a partially broken view of a part of an intake valve structure in a fifth embodiment embodying the third invention.

FIG. 14 is a front view showing a part of an intake valve in a sixth embodiment embodying the first invention.

FIG. 15 is a bottom view of the intake valve in the sixth embodiment.

FIG. 16 is a diagram of an opening of an intake port and the like viewed from a combustion chamber side in a sixth embodiment.

FIG. 17 is a front view showing a part of an intake valve in a seventh embodiment embodying the first invention.

FIG. 18 is a bottom view of the intake valve in the seventh embodiment.

FIG. 19 is a diagram of an opening of an intake port and the like viewed from a combustion chamber side in a seventh embodiment.

FIG. 20 is a front view showing a part of an intake valve in an eighth embodiment of the first invention.

FIG. 21 is a bottom view of the intake valve in the eighth embodiment.

FIG. 22 is a bottom view of the intake valve of the eighth embodiment.

FIG. 23 is a view of the opening of the intake port and the like as seen from the combustion chamber side in the eighth embodiment.

FIG. 24 is a front view showing a part of the intake valve in the ninth embodiment of the first invention.

FIG. 25 is a bottom view of the intake valve in the ninth embodiment.

FIG. 26 is a view of the opening of the intake port and the like as seen from the combustion chamber side in the ninth embodiment.

FIG. 27 is a perspective view of the intake valve structure of the tenth embodiment, partially cut away.

FIG. 28 is a perspective view showing a partially cutaway intake valve structure in the eleventh embodiment.

FIG. 29 is a plan view showing an intake valve, a stem guide and the like in a twelfth embodiment.

FIG. 30 is a side view showing an intake valve, a stem guide and the like in a twelfth embodiment.

FIG. 31 is a plan view showing an intake valve, a stem guide and the like in a twelfth embodiment.

FIG. 32 is a cross-sectional view showing an enlarged mating surface of both valve pieces in another embodiment embodying the fourth invention.

FIG. 33 is a cross-sectional view showing an enlarged mating surface of both valve pieces in another embodiment in which the fourth invention is embodied.

FIG. 34 is a cross-sectional view showing, in an enlarged manner, a mating surface of both valve pieces in another embodiment embodying the fourth invention.

FIG. 35 is a cross-sectional view showing, in an enlarged manner, a mating surface of both valve pieces in another embodiment embodying the third invention.

FIG. 36 is a perspective view showing a partially cutaway intake valve structure in another embodiment.

FIG. 37 is a sectional view showing an intake valve structure in the prior art.

[Explanation of symbols]

2 ... combustion chamber, 3 ... intake port, 4 ... opening, 6, 20,
22, 33 ... Intake valve, 8, 23, 36, 39 ... Valve head portion,
9, 10, 24, 25, 37, 38, 43 to 45 ... Stem, 15, 15A, 15B ... Shim, 18, 19, 34,
35, 40-42 ... Valve piece, 21 ... Sealing material.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location // F02F 1/42 HE

Claims (4)

[Claims] 1. An intake / exhaust valve for opening / closing an opening of an intake / exhaust port communicating with a combustion chamber, the internal combustion engine having a valve head portion capable of opening / closing the opening portion and a plurality of stems extending from the valve head portion. In an intake / exhaust valve structure for an engine, each stem is formed integrally with the valve head portion, and the valve head portion is formed so as to be divided into a plurality of valve pieces between the respective stems. Engine intake and exhaust valve structure. 2. An intake / exhaust valve for opening / closing an opening of an intake / exhaust port communicating with a combustion chamber, the internal combustion engine having a valve head portion capable of opening / closing the opening portion and a plurality of stems extending from the valve head portion. An intake / exhaust valve structure for an internal combustion engine, characterized in that at least one of the stem and the valve head portion are separately formed and assembled. 3. The intake / exhaust valve structure according to claim 1, wherein a part of the valve pieces adjacent to each other is vertically overlapped, and the overlapped lower valve piece precedes the upper valve piece. An intake / exhaust valve structure for an internal combustion engine, wherein the intake / exhaust valve structure is configured so as to open at the same time and close at a later time. 4. The intake / exhaust valve structure according to claim 1, 2 or 3, wherein a flexible sealing material is provided between the divided valve pieces or between the valve head portion and the stem. An intake / exhaust valve structure for an internal combustion engine, characterized in that a valve is interposed.