JP2000097004A - Non-rotating mechanism for 3D cam valve lifter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a turn stopper mechanism which is for a valve lifter for an internal combustion engine and does not degrade the roundness of the outer surface of valve lifter and the inner surface of the lifter bore. SOLUTION: A projecting engagement part 19d is formed on the inner surface 19c of a valve lifter 19. On this part 19d, a notch 9h in a guide member 9a is fitted, and the valve lifter 19 is movable in the axial direction without rotating inside the lifter bore 9b. It is only required that the outside surface 19a of the valve lifter 19 is shaped cylindrical smoothly, and since there is no need to form any projection or groove, the roundness of the valve lifter 19 is not degraded. There is neither need to form any groove at the inner surface of the lifter bore 9b, so that the roundness of the inner surface of lifter bore 9b is not degraded.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotation preventing mechanism for a three-dimensional cam valve lifter used in an internal combustion engine.

[0002]

2. Description of the Related Art Conventionally, there has been known a variable valve timing mechanism for varying the opening / closing valve timing of an intake valve or an exhaust valve of an internal combustion engine in accordance with the operation state of the internal combustion engine. As one type of this variable valve timing mechanism, FIG.
6, the opening / closing valve timing is adjusted by making the lift amount of a valve 1018 variable by using a three-dimensional cam 1011 movable in the rotation axis direction (the direction of arrow Z in the drawing) (Japanese Patent Application Laid-Open No. H10-121926). Etc.) are known.

In such a variable valve timing mechanism using a three-dimensional cam, the inclination angle of the cam surface 1011a changes according to the rotation. Therefore, the valve lifter 1019
A cam follower 1023 is swingably disposed on the upper surface 1019a of the cam surface 1019a so as to correspond to a change in the inclination angle of the cam surface 1011a. The upper surface 1019a of the valve lifter 1019
Is formed with a guide groove 1021 extending in parallel with the rotation direction of the three-dimensional cam 1011. By disposing a semi-cylindrical cam follower 1023 in the guide groove 1021, the cam follower 1023 is swingably supported. In this way, the three-dimensional cam 1011 and the valve lifter 1019 are maintained in a sufficient contact state to improve the durability.

In this configuration, a semi-cylindrical cam follower 1 is provided.
It is necessary to always maintain the swing axis direction (the direction of arrow S in the drawing) of 023 parallel to the rotation direction of the three-dimensional cam 1011. For this reason, the valve lifter 10 serves as a detent mechanism.
A projection 1025 is provided on the outer peripheral surface 1019b of
A guide groove is formed in the inner peripheral surface of the lifter bore 1029 on the cylinder head 1027 side in the axial direction. This projection 1
025 is engaged with the guide groove on the side of the lifter bore 1029, thereby preventing the valve lifter 1019 from rotating in the axial direction while allowing the valve lifter 1019 to move in the axial direction.

[0005]

The above-mentioned valve lifter 10
The outer peripheral surface 1019b of the substrate 19 and the corresponding inner peripheral surface of the lifter bore 1029 are required to have a roundness of several μm level. However, when the above-described projections and grooves are formed to form the rotation preventing mechanism, the valve lifter 1 formed with high precision is formed.
019 and the roundness of the lifter bore 1029 may be significantly deteriorated.

An object of the present invention is to provide a rotation preventing mechanism which does not deteriorate the roundness of the outer peripheral surface of the valve lifter and the inner peripheral surface of the lifter bore.

[0007]

According to a first aspect of the present invention, there is provided a valve lifter for a three-dimensional cam, which is housed in a cylindrical lifter bore provided in a cylinder head of an internal combustion engine, and has a profile in a direction of a rotation axis. For a cylindrical valve lifter that reflects the lift amount of the three-dimensional cam, which changes according to the rotation of the internal combustion engine by contacting the cam surfaces of different three-dimensional cams through a swing follower, with the valve opening degree. A detent mechanism used, provided on the inner peripheral surface of the valve lifter, a protrusion-shaped or groove-shaped engaging portion provided along an axial direction of the inner peripheral surface, and provided on the cylinder head side. By engaging with the engaging portion provided on the inner peripheral surface of the valve lifter, the valve lifter is allowed to move in the axial direction of the lifter bore, but is rotated around the axis. Characterized in that a guide member not permitted.

A projection or groove-shaped engaging portion is formed on the inner peripheral surface of the cylindrical valve lifter, and a guide member extends from the cylinder head and engages with the engaging portion. As a result, rotation of the valve lifter is prevented.

As described above, no engaging portion such as a projection or a groove is formed on the outer peripheral surface of the valve lifter requiring a high roundness. Therefore, the roundness of the valve lifter does not deteriorate due to the formation of the engagement portion. Further, since the engaging portion is not formed on the outer peripheral surface of the valve lifter, it is not necessary to form a corresponding guide mechanism on the inner peripheral surface of the lifter bore. Therefore, the roundness of the inner peripheral surface of the lifter bore does not deteriorate.

According to a second aspect of the present invention, in the rotation preventing mechanism for a three-dimensional cam valve lifter according to the first aspect, the guide member includes a cylinder in which a valve spring combined with the valve lifter is disposed. The head is mounted on a spring seat.

As described above, the guide member may be attached to the spring seat of the cylinder head, and can be realized with a relatively simple configuration. 3. The method according to claim 3,
In the rotation preventing mechanism for the three-dimensional cam valve lifter, the engaging portion is formed in a projection shape with respect to the configuration according to claim 1 or 2, and the guide member has a groove or a groove along an axial direction of an inner peripheral surface of the valve lifter. A notch is formed, and the groove or the notch is engaged with the engaging portion.

In the case where the engaging portion is in the form of a protrusion, the guide member is formed with a groove or a notch along the axial direction of the inner peripheral surface of the valve lifter, so that the guide has a relatively simple structure. The engaging portion can be engaged. By this engagement, the valve lifter can be guided from the inside so that it cannot rotate and can move in the axial direction.

According to a fourth aspect of the present invention, the three-dimensional cam valve lifter rotation preventing mechanism is housed in a cylindrical lifter bore provided in a cylinder head of the internal combustion engine, and has a different profile in the rotation axis direction. A non-rotating mechanism used for a cylindrical valve lifter that reflects the lift amount of the three-dimensional cam, which changes according to the rotation of the internal combustion engine by contacting the surface via a swinging follower, with the valve opening. The valve lifter has a center axis between an outer peripheral surface and an inner peripheral surface of the valve lifter offset, and is provided on the cylinder head side, and has a maximum thickness side wall portion and a minimum thickness side wall generated by the offset. 2 of the inner peripheral surface of the valve lifter divided by
A guide member slidably in contact with each of the two regions or on the inner peripheral surface corresponding to the minimum thickness side wall portion.

As described above, since the central axes of the outer peripheral surface and the inner peripheral surface of the valve lifter are offset, the side wall portion existing between the outer peripheral surface and the inner peripheral surface of the valve lifter has a minimum thickness to a maximum thickness. There is a difference in thickness in the circumferential direction up to. Among these, the inner peripheral surface of the valve lifter can be divided into two regions by the side wall portion having the largest thickness and the side wall portion having the smallest thickness. Then, the guide member is slidably contacted with each of the regions, or is slidably contacted with the inner peripheral surface corresponding to the minimum thickness side wall portion.

The guide member is formed on the inner surface of the valve lifter.
When the valve lifter tries to rotate in any direction, the side wall of the valve lifter that is thicker than the gap between the lifter bore and the guide member that is in contact with either area Because of the approach, rotation of the valve lifter is prevented. However, since the thickness of the axial side wall of the valve lifter does not change, the axial movement of the valve lifter is not prevented.

When the guide member is in contact with the minimum thickness side wall portion of the inner peripheral surface of the valve lifter, the gap between the guide member and the lifter bore is larger than the distance between the guide member and the lifter bore regardless of the direction in which the valve lifter rotates. Since the side wall portion of the valve lifter is about to enter, rotation of the valve lifter is prevented. Further, since the thickness of the side wall portion in the axial direction of the valve lifter does not change even in the side wall portion having the minimum thickness, the movement of the valve lifter in the axial direction is not prevented.

As described above, since the engaging portion itself is not formed, the outer peripheral surface of the valve lifter which requires a high roundness can be kept completely cylindrical. Therefore, the roundness of the valve lifter does not deteriorate. Further, since the engaging portion is not formed on the outer peripheral surface of the valve lifter, it is not necessary to form a corresponding guide mechanism on the inner peripheral surface of the lifter bore. Therefore, the roundness of the inner peripheral surface of the lifter bore does not deteriorate.

Further, since there is no need to provide an engaging portion also on the inner peripheral surface of the valve lifter, it is not necessary to provide a structure for engaging with this engaging portion on the guide member, so that manufacturing is easy.

According to a fifth aspect of the present invention, in the rotation preventing mechanism for a valve lifter for a three-dimensional cam, the guide member is slidably in contact with the entire circumference of the inner peripheral surface of the valve lifter. It is characterized by being formed in a cylindrical shape.

In this manner, the guide member may be formed in a cylindrical shape so as to slidably contact the entire inner peripheral surface of the valve lifter. Even with such a configuration, the configuration of claim 4 can be satisfied, and the manufacture is easy because the rotation of the valve lifter can be sufficiently prevented with a simple cylindrical shape. In addition, since the surface pressure when sliding with the inner peripheral surface of the valve lifter is reduced, the durability of the rotation preventing mechanism is improved.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS [First Embodiment] FIG. 1 shows a valve drive mechanism to which a three-dimensional cam valve lifter rotation preventing mechanism according to a first embodiment is applied, and FIG. 2 shows the configuration of FIG. 1 shows a schematic configuration of a vehicular gasoline engine (hereinafter, referred to as an engine) 1. This engine 1
Is a DOHC4 valve type.

Cylinder block 2 constituting engine 1
Is provided with a plurality of cylinders 3, and a piston 4 is arranged in each cylinder 3. Each piston 4 is connected to a crankshaft 6 supported by a crankcase 5 by a connecting rod 7. A crankshaft timing pulley 8 is provided at one end of the crankshaft 6.

On the cylinder head 9 provided above the cylinder block 2, an intake camshaft 10 is supported by a plurality of journal bearings 22 so as to be rotatable and movable in the direction of the rotation axis (the direction of the arrow shown in FIG. 1). ing. The intake-side camshaft 10 is provided integrally with two intake-side cams 11 for each cylinder 3. Further, the exhaust-side camshaft 12 is supported on the cylinder head 9 by a plurality of journal bearings so as to be rotatable and immovable in the rotation axis direction. The exhaust-side camshaft 12 is provided integrally with two exhaust-side cams 13 for each cylinder 3.

The camshaft timing pulley 14 and the shaft drive mechanism 1
5 are provided integrally. On the other hand, one end of the exhaust side camshaft 12 is provided with a camshaft timing pulley 16.
Is provided. Each camshaft timing pulley 1
Reference numerals 4 and 16 are connected to the crankshaft timing pulley 8 by a timing belt 17. With such a configuration, when the crankshaft 6 rotates, the intake-side camshaft 10 and the exhaust-side camshaft 12 are driven to rotate.

Each cylinder 3 is provided with two intake valves 18. The intake valve 18 is drivingly connected to the intake cam 11 via a valve lifter 19. Each of the valve lifters 19 is slidably supported in a lifter bore 9 b provided in the cylinder head 9, and is non-rotatably and slidably guided by a cylindrical guide member 9 a attached to the cylinder head 9 as described later. Have been.

Further, each cylinder 3 has an exhaust valve 20.
Are arranged two by two. The exhaust valve 20 is drivingly connected to the exhaust-side cam 13 via a valve lifter 21. Each valve lifter 21 is slidably supported in a lifter bore (not shown) provided in the cylinder head 9.

The intake cam 11 supported by the intake camshaft 10 is a three-dimensional cam having a cam surface 11a.
Is formed so as to continuously and continuously change in the direction of the rotation axis. On the other hand, the exhaust side camshaft 1
The exhaust side cam 13 supported by 2 is a normal cam whose profile does not change in the direction of its rotation axis.

The exploded perspective view of FIG. 3, the perspective view of FIG. 4, the longitudinal sectional view of FIG. 5, and the transverse sectional view of FIG. The configuration around it is shown. As shown, the valve lifter 19
Is formed in a cylindrical shape, and its outer peripheral surface 19a is a smooth cylindrical shape, and has no projections or grooves. The lifter bore 9b in which the valve lifter 19 is housed also forms a smooth cylindrical surface in which no projection or groove is formed corresponding to the outer peripheral surface 19a of the valve lifter 19.

As shown in FIG. 5, the spring seat 9c provided on the cylinder head 9 is formed in a stepped cylindrical shape. The guide member 9a is press-fitted to the first stage of the spring seat 9c and fixed to the cylinder head 9. A ring-shaped spring seat 9d is arranged on the first-stage ring-shaped upper surface of the spring seat 9c, and the lower end of a spring 18a surrounded by the guide member 9a and the valve lifter 19 abuts.

The stem 18b of the intake valve 18 passes through the center hole 9e of the spring seat 9c via the valve guide 9f. Stem end 1 which is the upper end of this stem 18b
The upper end of the spring 18a contacts the retainer 18d attached to the retainer 8c to urge the retainer 18d upward. Therefore, the stem end 18c contacts the thick portion 19b inside the valve lifter 19 from below, and urges the entire valve lifter 19 toward the intake cam 11 side.

The diameter of the outer peripheral surface 9g of the guide member 9a is formed slightly smaller than the diameter of the inner peripheral surface 19c of the valve lifter 19, and the guide member 9a is inserted into the valve lifter 19 as shown in FIGS. Are placed in a state.
On the inner peripheral surface 19c of the valve lifter 19, a protruding engagement portion 19d is formed substantially near the center in the vertical direction.
A notch 9h is formed in the guide member 9a along the axial direction of the inner peripheral surface 19c of the valve lifter 19 corresponding to the position of the projecting engagement portion 19d. By arranging the engaging portion 19d in the notch 9h, the engaging portion 19d can move only in the vertical direction along the notch 9h. Therefore, the valve lifter 19 is guided so as not to rotate with respect to the guide member 9a and to be movable in the axial direction (the direction of arrow B in the drawing). The guide member 9a is a cylinder head 9
, The valve lifter 19 can move in the axial direction without rotating in the lifter bore 9b.

That is, even when the intake cam 11 pushes down the valve lifter 19 from the state shown in FIGS. 4 and 5 to the state shown in FIGS. There is no rotation in 9b. Further, even if the spring 18a pushes the valve lifter 19 back from the state of FIGS. 7 and 8 to the state of FIGS.
9 does not rotate in the lifter bore 9b.

A cam follower holder 24 is integrally formed on the top surface 19k of the valve lifter 19, and a cam follower 25 (corresponding to a swing follower) is supported on the cam follower holder 24 so as to swing in the width direction. I have. As described above, the valve lifter 19 is biased toward the intake cam 11 by the spring 18a. For this reason, the cam sliding surface 25a of the cam follower 25 is pressed toward the cam surface 11a of the intake cam 11, and comes into sliding contact with the cam surface 11a, and the cam follower 25 swings according to the cam surface 11a. Move.

As shown in an exploded perspective view of FIG. 3, the cam follower 25 has a semi-cylindrical main body 25b and a main body 25b.
An enlarged portion 25c having a larger diameter than the main body 25b is provided at a central portion in the swing axis direction (the direction of the arrow C in FIG. 3) in FIG. When the cylindrical outer peripheral surface of the main body 25b is disposed in the cam follower holder 24 of the valve lifter 19 as shown in FIGS. 4 and 7, when the cam follower 25 swings, a semicircular guide groove formed in the cam follower holder 24. The sliding surface 25d slides on the sliding surface 24a.

The enlarged portion 25c of the cam follower 25
Is an enlarged groove 24b formed at the center of the guide groove 24a (the center in the direction of arrow C) corresponding to the enlarged portion 25c.
Is housed inside. Accordingly, the thrust surface 25e of the enlarged portion 25c and the thrust surface 24c of the enlarged groove 24b are formed.
And the cam follower 25 can be prevented from moving in the swing axis direction indicated by the arrow C. That is, the cam follower 25 arranged on the cam follower holder 24 of the valve lifter 19 can swing around the swing axis, but cannot move in the swing axis direction.

When the cam follower 25 swings,
A moment acts on the valve lifter 19 via the cam follower 25 in the direction of rotation in the lifter bore 9b. However, the valve lifter 19 on which the cam follower 25 is mounted is, as described above, the inner peripheral surface 19 of the valve lifter 19.
By the engagement between the engaging portion 19d provided on the guide member 9c and the notch 9h provided on the guide member 9a, the movable member can be moved up and down without rotating. Therefore, the cam follower 25 swings in accordance with the rotation of the intake cam 11 while maintaining the swing axis direction.

According to the first embodiment described above, the following effects can be obtained. (I). In the first embodiment, the outer peripheral surface 19a of the valve lifter 19 requiring a high roundness may be formed in a smooth cylindrical shape, and there is no need to form protrusions and grooves.
Therefore, since it is not necessary to attach a projection to the outer peripheral surface 19a of the valve lifter 19 by welding or press fitting or to form a groove, the roundness of the valve lifter 19 does not deteriorate.

Further, since no protrusion or groove is formed on the outer peripheral surface 19a of the valve lifter 19, it is not necessary to form a corresponding groove or protrusion on the inner peripheral surface of the lifter bore 9b. Therefore, the roundness of the inner peripheral surface of the lifter bore 9b does not deteriorate.

(B). In the first embodiment, after the engaging portion 19d is formed on the inner peripheral surface 19c of the valve lifter 19, the outer peripheral surface 19a of the valve lifter 19 can be ground to obtain high roundness. Therefore, even if the processing on the inner peripheral surface 19c of the valve lifter 19 may affect the roundness of the outer peripheral surface 19a, this influence can be eliminated. When projections are present on the outer peripheral surface as in the related art, it is extremely difficult and practically impossible to obtain high roundness after the formation of the projections.

(C). The guide member 9a is attached to a spring seat 9c of the cylinder head 9. Moreover, it is attached to the cylindrical spring seat 9c by press fitting. Therefore, it can be realized with a relatively simple configuration and simple processing, and the productivity is also improved.

(D). Since the engaging portion 19d is in the shape of a protrusion, the guide member 9a is connected to the inner peripheral surface 19c of the valve lifter 19.
By simply forming the notch 9h along the axial direction, a configuration that engages with the engagement portion can be formed by a relatively simple configuration and processing. Therefore, productivity is improved.

[Embodiment 2] FIGS. 9 to 14 show the structure of the valve lifter 119 on the intake valve side and its periphery according to Embodiment 2 of the present invention. 9 is an exploded perspective view, FIG. 10 is a perspective view, FIG. 11 is a longitudinal sectional view, FIG. 12 is a transverse sectional view (A1-A1 cross section in FIG. 11), and FIGS. 13 and 14 show a change in position of the valve lifter 119. FIG. It should be noted that components having similar or identical functions to the components described in the first embodiment are denoted by reference numerals obtained by adding 100 to the reference numerals of the corresponding components in the first embodiment. Other configurations are the same as those of the first embodiment.

The second embodiment is different from the first embodiment in that the inner peripheral surface 119c of the valve lifter 119 has no projecting engagement portion, and as shown in FIGS. The point is that the inner peripheral surface 119c is offset with respect to the surface 119a.

The guide member 109a press-fit into the spring seat 109c of the cylinder head 109 is not formed with a notch but is formed as a simple cylindrical body.

As described above, the center axes of the outer peripheral surface 119a and the inner peripheral surface 119c of the valve lifter 119 are offset. For this reason, the outer peripheral surface 119 of the valve lifter 119
a between the inner peripheral surface 119c and the inner peripheral surface 119c
Has a thickness difference in the circumferential direction from the minimum thickness to the maximum thickness.

The inner peripheral surface 11 of the valve lifter 119
An outer peripheral surface 109g of the guide member 109a is slidably in contact with the entire periphery of 9c. As a result, the guide member 1
Also in the gap between the outer peripheral surface 109g of the housing 09a and the lifter bore 109b, there is a difference in the circumferential direction from the minimum to the maximum.

Therefore, in this stored state, the valve lifter 119 cannot rotate, and can move only in the vertical direction (the direction of the arrow B1 in the figure) while maintaining the swing axis direction of the cam follower 125 (the direction of the arrow C1 in the figure). In addition, the valve lifter 1
19. Guide member 109a and spring seat 109c
Can enter and exit from a slight gap between the valve lifter 119 and the guide member 109a. Therefore, the internal pressure of the space is increased by the valve lifter 119.
Does not hinder the movement of The valve lifter 11
Even if the space between the guide member 9 and the guide member 109a is completely adhered, air can enter and exit if a gap is provided in a part between the spring seat 109c and the guide member 109a.

According to the second embodiment described above, the following effects can be obtained. (I). The same effects as (a) and (c) of the first embodiment are obtained. (B). It is not necessary to provide a projection or groove-shaped engaging portion on the inner peripheral surface 119c of the valve lifter 119, and it is not necessary to provide a configuration for engaging with the projection or groove on the guide member 109a. Is improved.

(C). Since it is not necessary to form the engaging portion on the inner peripheral surface 119c of the valve lifter 119 as in the first embodiment, the outer peripheral surface 119a of the valve lifter 119 can be formed with a high roundness from the beginning without grinding again. High in nature.

(D). Outer peripheral surface 11 of valve lifter 119
Both the inner peripheral surface 119c and the inner peripheral surface 119c may be formed in a cylindrical shape, and the outer peripheral surface 109g of the guide member 109a may be formed in a cylindrical shape. Therefore, the rotation of the valve lifter 119 can be sufficiently prevented with a simple configuration. Therefore, manufacturing is easy and productivity is high.

(E). Inner peripheral surface 11 of valve lifter 119
Since 9c and the outer peripheral surface 109g of the guide member 109a are in contact with each other over a wide area, the surface pressure when both slide is reduced, and the durability of the rotation preventing mechanism is improved.

[Third Embodiment] FIG. 15 is a longitudinal sectional view of the third embodiment. A configuration having a function similar or identical to that of the configuration described in the first embodiment is indicated by a reference numeral obtained by adding 200 to the reference numeral of the corresponding configuration in the first embodiment.

The first embodiment differs from the first embodiment in that a guide member 209a is provided.
Is different. Other configurations are the same as the first embodiment. A lower end portion of the guide member 209a is bent inward in a concave shape in cross section to form a spring seat portion 209d. Then, the inner surface of the spring seat portion 209d is pressed into the outer peripheral portion of the second stage of the cylindrical spring seat 209c, and the entire guide member 209a is brought into contact with the cylinder head 2.
09.

The spring seat portion 209d contacts the lower end of the spring 218a and plays the role of the ring-shaped spring seat 9d of the first embodiment. According to the third embodiment described above, the following effects can be obtained.

(A). The same effect as in the first embodiment is obtained. (B). Since the guide member 209a also serves as a spring seat, the number of parts is reduced, and an increase in manufacturing cost can be prevented.

(C). Since the spring seat portion 209d having a concave cross section is formed at one end of the guide member 209a, the rigidity of the guide member 209a itself increases,
The guide for moving the valve lifter 219 can be highly accurate. Further, the guide member 209a can be made thinner and lighter.

[Other Embodiments] The guide member 109a of the second embodiment has the same configuration as the spring seat portion 209d having a concave cross section provided at the lower end of the guide member 209a of the third embodiment. Is also good. This makes it possible to reduce the number of components and increase the rigidity of the guide member 109a.

In the first and third embodiments, the guide member is provided with a notch to engage with the engaging portion on the inner peripheral surface of the valve lifter. However, a groove is formed on the outer peripheral surface of the guide member to form the valve lifter. You may make it engage with the engaging part of an inner peripheral surface.

In the first and third embodiments, the protruding engagement portion is provided on the inner peripheral surface of the valve lifter, and the notch is provided on the guide member. An extended groove-shaped engaging portion may be provided, and the guide member may be provided with a projection and engaged with each other.

In the second embodiment, the guide member is formed in a cylindrical shape, and is in contact with the inner peripheral surface of the valve lifter all around the outer peripheral surface of the guide member. In addition, instead of being in contact with the entire circumference of the inner surface of the valve lifter, the two regions of the inner surface of the valve lifter, which are divided by the maximum thickness portion and the minimum thickness portion of the side wall portion of the valve lifter, respectively, It may be configured to contact. Further, a configuration in which the contact is made at one place at the minimum thickness portion of the side wall portion may be employed. As described above, the rotation of the valve lifter can be prevented even without contacting the entire circumference.

Although the embodiments of the present invention have been described above, the embodiments of the present invention include the following various technical items in addition to the technical items described in the claims. It should be noted that it has.

(1). 6. The three-dimensional cam valve lifter detent according to claim 4, wherein the guide member is attached to a spring seat of the cylinder head in which a valve spring combined with the valve lifter is arranged. mechanism.

(2). The guide member forms a spring seat portion at one end, and is attached to the spring seat of the cylinder head where the valve spring combined with the valve lifter is disposed by the spring seat portion. 2. The valve spring according to claim 1, wherein said valve spring receives one end of said valve spring.
6. The mechanism for preventing rotation of a valve lifter for a three-dimensional cam according to any one of items 5 to 5.

[0064]

According to the first aspect of the present invention, in the three-dimensional cam valve lifter detent mechanism, a projecting or groove-shaped engaging portion is formed on the inner peripheral surface of the cylindrical valve lifter. A guide member extends from and engages with the cylinder head. This prevents rotation of the valve lifter. As described above, no engaging portion such as a protrusion or a groove is formed on the outer peripheral surface of the valve lifter requiring a high roundness. Therefore, the roundness of the valve lifter does not deteriorate due to the formation of the engagement portion. Further, since the engaging portion is not formed on the outer peripheral surface of the valve lifter, it is not necessary to form a corresponding guide mechanism on the inner peripheral surface of the lifter bore. Therefore, the roundness of the inner peripheral surface of the lifter bore does not deteriorate.

In the rotation preventing mechanism for a valve lifter for a three-dimensional cam according to the second aspect, the guide member is attached to the spring seat of the cylinder head, which is relatively simple. It can be realized with a configuration.

According to a third aspect of the present invention, in the rotation preventing mechanism for a valve lifter for a three-dimensional cam, the engaging portion has a projecting shape, and the guide member is formed on the inner peripheral surface of the valve lifter. A groove or notch is formed along the axial direction. For this reason, it is possible to engage with the protruding engagement portion with a relatively simple configuration. By this engagement, the valve lifter can be guided from the inside so that it cannot rotate and can move in the axial direction.

In the rotation preventing mechanism for a valve lifter for a three-dimensional cam according to the fourth aspect, since the central axes of the outer peripheral surface and the inner peripheral surface of the valve lifter are offset, the valve lifter does not need to have an engaging portion. Rotation is blocked,
The movement of the valve lifter in the axial direction is not prevented. As described above, since the engagement portion itself is not formed, the outer peripheral surface of the valve lifter that requires a high roundness can be completely cylindrical. Therefore, the roundness of the valve lifter does not deteriorate. Further, since the engaging portion is not formed on the outer peripheral surface of the valve lifter, it is not necessary to form a corresponding guide mechanism on the inner peripheral surface of the lifter bore. Therefore, the roundness of the inner peripheral surface of the lifter bore does not deteriorate. In addition, since the engagement portion does not need to be provided also on the inner peripheral surface of the valve lifter, the structure for engaging with the engagement portion does not need to be provided on the guide member, so that the manufacturing is easy.

According to the fifth aspect of the present invention, in the rotation preventing mechanism for a valve lifter for a three-dimensional cam, the guide member can be made cylindrical and slidable around the entire inner peripheral surface of the valve lifter. To make contact. Even with such a configuration, the configuration of claim 4 can be satisfied, and the manufacture is easy because the rotation of the valve lifter can be sufficiently prevented with a simple cylindrical shape.
In addition, since the surface pressure when sliding with the inner peripheral surface of the valve lifter is reduced, the durability of the rotation preventing mechanism is improved.

[Brief description of the drawings]

FIG. 1 is a configuration explanatory view of a valve drive mechanism to which a valve lifter rotation preventing mechanism according to a first embodiment is applied.

FIG. 2 is a schematic configuration diagram of a gasoline engine for a vehicle to which the valve drive mechanism of FIG. 1 is applied.

FIG. 3 is an exploded perspective view of the rotation preventing mechanism according to the first embodiment.

FIG. 4 is a perspective view of a rotation preventing mechanism according to the first embodiment.

FIG. 5 is a longitudinal sectional view of the rotation preventing mechanism according to the first embodiment.

FIG. 6 is a cross-sectional view of the rotation preventing mechanism according to the first embodiment.

FIG. 7 is a perspective view illustrating the operation of the rotation preventing mechanism according to the first embodiment.

FIG. 8 is a vertical sectional view illustrating the operation of the rotation preventing mechanism according to the first embodiment.

FIG. 9 is an exploded perspective view of a rotation preventing mechanism according to the second embodiment.

FIG. 10 is a perspective view of a rotation preventing mechanism according to the second embodiment.

FIG. 11 is a longitudinal sectional view of a rotation preventing mechanism according to the second embodiment.

FIG. 12 is a cross-sectional view of the rotation preventing mechanism according to the second embodiment.

FIG. 13 is a perspective view illustrating the operation of the rotation preventing mechanism according to the second embodiment.

FIG. 14 is a longitudinal sectional view illustrating the operation of the rotation preventing mechanism according to the second embodiment.

FIG. 15 is a longitudinal sectional view of a rotation preventing mechanism according to the third embodiment.

FIG. 16 is an explanatory diagram of a configuration of a conventional detent mechanism.

[Explanation of symbols]

1 ... engine, 2 ... cylinder block, 3 ... cylinder,
4 piston, 5 crankcase, 6 crankshaft, 7 connecting rod, 8 crankshaft timing pulley, 9 cylinder head, 9a guide member, 9
b ... lifter bore, 9c ... spring seat, 9d ... spring seat, 9e ... center hole, 9f ... valve guide, 9g ...
Outer peripheral surface, 9h: Notch, 10: Intake side camshaft, 1
DESCRIPTION OF SYMBOLS 1 ... Intake side cam, 11a ... Cam surface, 12 ... Exhaust side camshaft, 13 ... Exhaust side cam, 14 ... Camshaft timing pulley, 15 ... Shaft drive mechanism, 16 ... Camshaft timing pulley, 17 ... Timing belt, 18
... intake valve, 18a ... spring, 18b ... stem,
18c: stem end, 18d: retainer, 19: valve lifter, 19a: outer peripheral surface, 19b: thick portion, 19c
... inner peripheral surface, 19d ... engaging part, 19k ... top surface, 20 ... exhaust valve, 21 ... valve lifter, 22 ... journal bearing, 24 ... cam follower holder, 24a ... guide groove, 2
4b: enlarged groove, 24c: thrust surface, 25: cam follower, 25a: cam sliding surface, 25b: main body, 25c: enlarged portion, 25d: sliding surface, 25e: thrust surface, 109: cylinder head, 109a: guide member , 109b ... lifter bore, 109c ... spring seat, 109g ... outer peripheral surface,
119: valve lifter, 119a: outer peripheral surface, 119c ...
Inner peripheral surface, 119e ... side wall, 125 ... cam follower, 2
09: cylinder head, 209a: guide member, 209
d: Spring seat part, 218a: Spring, 21
9 ... Valve lifter.

Claims (5)

[Claims] 1. A three-dimensional cam which is housed in a cylindrical lifter bore provided in a cylinder head of an internal combustion engine and has a different profile in a rotation axis direction through a swing follower. A detent mechanism used for a cylindrical valve lifter that reflects a lift amount of the three-dimensional cam, which changes according to rotation of an internal combustion engine, in a valve opening, provided on an inner peripheral surface of the valve lifter, A protrusion-shaped or groove-shaped engagement portion provided along the axial direction of the inner peripheral surface; and a engagement member provided on the cylinder head side and provided on an inner peripheral surface of the valve lifter. And a guide member that allows the valve lifter to move in the axial direction of the lifter bore but does not allow rotation about the axis. Lid lock mechanism. 2. The three-dimensional cam valve lifter according to claim 1, wherein the guide member is mounted on a spring seat of the cylinder head where a valve spring combined with the valve lifter is disposed. Detent mechanism. 3. The engaging portion has a projection shape, and the guide member forms a groove or a notch along an axial direction of an inner peripheral surface of the valve lifter, and the groove or the notch is formed by the engaging portion. 3. The method as claimed in claim 1, wherein the third member is engaged with the third member.
Non-rotating mechanism for two-dimensional cam valve lifters. 4. A three-dimensional cam, which is housed in a cylindrical lifter bore provided in a cylinder head of an internal combustion engine and has a different profile in the direction of the rotation axis, contacts a cam surface of a three-dimensional cam via a swing follower. A non-rotating mechanism used for a cylindrical valve lifter that reflects a lift amount of the three-dimensional cam, which changes according to rotation of an internal combustion engine, into a valve opening, wherein the valve lifter includes an inner peripheral surface and an inner peripheral surface of the valve lifter. The center axis of the valve lifter is offset from the peripheral surface of the valve lifter and provided on the cylinder head side and divided by a maximum thickness side wall portion and a minimum thickness side wall portion caused by the offset. A guide member slidably contacting each of the two regions or on the inner peripheral surface corresponding to the minimum thickness side wall portion. Detent mechanism of the valve lifter for the dimension cam. 5. The valve lifter for a three-dimensional cam according to claim 4, wherein the guide member is formed in a cylindrical shape so as to be slidably in contact with the entire inner peripheral surface of the valve lifter. Stop mechanism.