JPH11294126A - Valve system for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To compact a valve system by interlocking and connecting an actuator to one of component elements of a planetary gear type or planetary friction type power transmission means for finely changing actuation characteristics of an engine valve, and enabling close disposition of a cam shaft to the power transmission means. SOLUTION: Among an inner ring 37, an outer ring, and a carrier composing a power transmission means 361, a roller 44 to get in rolling-contact with a valve cam 291 is shaft-supported between tip parts of a pair of roller holding arms 45 extended from one of the outer ring and the carrier toward the valve cam 291 , and a recess 45b to enable invasion of a part of the valve cam 291 inside a tangent line connecting an outer circumference of the outer ring and an outer circumference of the roller 44 is formed in a side surface of the roller holding arm 45 on the side of the valve cam 291 .

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve train for an internal combustion engine, and more particularly to a valve train for an internal combustion engine capable of changing the operating characteristics of an engine valve such as an intake valve or an exhaust valve in accordance with the operating state of the engine. About.

[0002]

2. Description of the Related Art Conventionally, such a valve train is already known, for example, from Japanese Patent Publication No. 7-107368.

[0003]

By the way, in the above-mentioned prior art, the rocker arm connected to the engine valve is driven by selectively switching between a plurality of types of valve cams having different cam profiles. The operating characteristics of the engine valve are switched between two or three stages according to the operating state of the engine. However, in order to further improve engine performance such as engine output torque, fuel consumption and exhaust properties, it is desirable that the operating characteristics of the engine valve can be more finely switched in accordance with the engine operating state. In the configuration of the valve device, more types of valve operating cams having different cam profiles are required, which increases the size of the valve operating device, and is difficult to realize.

Therefore, the applicant of the present invention has proposed that a planetary gear type or planetary friction type power transmission means having an inner ring, an outer ring and a carrier as components is provided between a camshaft and an engine valve, and one configuration of the power transmission means is provided. Rotational position control means is connected to the element, and by controlling the amount of rotation of the component by the rotational position control means, the operating characteristics of the engine valve can be reduced in a small configuration that does not require a plurality of valve cams. A valve train that can be finely changed has already been proposed (Japanese Patent Application No. 8-232283).

[0005] In using the proposed valve train, it is desirable to make the axis of the cam shaft as close as possible to the outer periphery of the power transmission means in order to make the valve train compact. Moreover, in order to reduce the frictional resistance between one of the components of the power transmission means and the interlocking of the valve operating cam and the connecting portion to reduce the valve operating load, the power transmission means is connected to one of the components. It is necessary to support a roller that is in rolling contact with the valve operating cam between the distal ends of the pair of roller holding arms.

However, in order to reduce the inertial weight of the power transmitting means, it is desirable to reduce the width of the power transmitting means along the axial direction of the camshaft as much as possible to reduce the weight of the power transmitting means. When the shaft length matches the width of the valve operating cam, a part of the roller and the valve operating cam becomes non-contact due to an assembly error or the like, and the contact area of the roller and the valve operating cam becomes smaller than the set value. As a result, uneven wear of the roller and the valve operating cam may occur due to the increase of the surface pressure. Therefore, even if there is an assembling error, the roller is brought into contact with the valve operating cam over its entire length in the axial direction to prevent uneven wear. It is desirable. From such a viewpoint, it is necessary that the axial length of the roller is set smaller than the width of the valve operating cam along the axial direction of the cam shaft, and as such, the width of the valve operating cam and the axial length of the roller are required. Once set, the relative positions of the camshaft and the power transmission means must be determined so that the roller holding arm and the valve cam do not interfere with each other. Limits arise.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and it has been made possible to finely change the operating characteristics of an engine valve, to reduce the valve operating load and to make the internal combustion engine compact. An object of the present invention is to provide a valve train for an engine.

[0008]

SUMMARY OF THE INVENTION To achieve the above object, an invention according to claim 1 is a valve operating apparatus for an internal combustion engine capable of changing the operating characteristics of an engine valve in accordance with the operating state of the engine. An inner ring rotatable about an axis parallel to a cam shaft on which the valve cam is provided, an outer ring rotatable around the same axis as the inner ring and surrounding the inner ring, and a planetary rotator disposed between the inner ring and the outer ring And a carrier that rotatably supports around an axis parallel to the axis of the inner ring and the outer ring and that rotates in conjunction with the revolution of the planetary rotator around the inner ring as a component, and A first component defined as one of an outer ring and a carrier is interlocked with and connected to the valve operating cam, and a second component defined as the other of the outer ring and the carrier or the inner ring of the components. Power transmission means having a component connected to the engine valve; rotation position control being connected to the third component to control a rotation position of a third component among the components of the power transmission means; Means for reducing the distance between the inner surfaces of the pair of roller holding arms to be smaller than the width of the valve cam along the axial direction of the camshaft. A roller extending on the valve cam side and rolling in contact with the valve cam between the end portions of both roller holding arms is pivotally supported, and is located inside a tangent connecting the outer periphery of the outer ring and the outer periphery of the roller. A concave portion that allows a part of the valve cam to enter into one side is formed on a side surface of the both roller holding arms on the valve cam side.

According to the above construction, the first and second components of the power transmission means, which include the inner race, the outer race and the carrier, are interlocked and connected to the valve cam and the engine valve, respectively. The rotation position of the third component is controlled by the rotation position control means, so that the rotation of the second component accompanying the rotation of the first component due to the rotation of the valve cam, that is, the rotation of the engine valve. The operation characteristics are controlled, and the rotation position of the third component is more finely controlled by the rotation position control means, whereby the operation characteristics of the engine valve can be more finely controlled. . Moreover, since the power transmission means is configured such that the inner ring, the outer ring, and the carrier constituting the power transmission means are rotatably arranged around the same axis, the power transmission means can be compactly assembled.
The size of the valve train can be reduced. Further, the first component is one of the outer race and the carrier, and a roller supported between the distal ends of a pair of roller holding arms connected to the outer race or the carrier is in rolling contact with the valve gear cam, The valve operating load can be reduced.
In addition, since the distance between the inner side surfaces of both roller holding arms is smaller than the width of the valve operating cam along the camshaft axis, the width of the power transmission means along the camshaft axial direction is made as small as possible to reduce the power. In addition to reducing the inertia weight by reducing the weight of the transmission means, even if there is an assembling error, the roller is brought into contact with the valve operating cam over its entire length in the axial direction to maintain the set surface pressure. Uneven wear of the cam can be prevented. In addition, a recess is formed on the side of the both roller holding arms on the valve cam side, which allows a part of the valve cam to enter into the inner side of the tangent connecting the outer circumference of the outer ring and the outer circumference of the roller. Therefore, it is possible to dispose the valve operating cam as close as possible to the outer periphery of the power transmitting means by avoiding interference between the valve operating cam and both roller holding arms, and to make the cam shaft and the power transmitting means as close as possible. Thus, the valve train can be made compact.

[0010] The invention according to claim 2 provides the above-described claim 1.
In addition to the configuration of the invention described, the carrier has a pair of support plates arranged in a ring plate shape and spaced apart in the rotation axis direction of the inner ring, and an axis parallel to the rotation axis of the inner ring. And a plurality of shafts provided between the two support plates to rotatably support each planetary rotator, and are pivotally supported between the distal ends of the roller holding arms integrally connected to the two support plates. One of the plurality of shafts is disposed on a straight line connecting the center of the roller and the center of the inner ring.

According to this structure, a load acts on the continuous portion of the two roller holding arms and the two support plates via the rollers from the valve cam. The strength of the continuous portion is controlled by each planetary rotating body. The carrier can be reinforced by one of a plurality of shafts that are rotatably supported, and the carrier can have sufficient strength without increasing the thickness of both support plates and both roller holding arms. It is possible to contribute to the weight reduction of the power transmission means and the valve train.

According to a third aspect of the present invention, in addition to the configuration of the first aspect of the present invention, the rollers are provided on upper side surfaces of both roller holding arms arranged so as to come into rolling contact with the valve operating cam from below. According to this configuration, the oil accumulated in the concave portion is guided to the power transmission means side, particularly to the roller side, so that the rotation of the roller is performed. Resistance can be reduced.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described based on embodiments of the present invention shown in the accompanying drawings.

FIGS. 1 to 4 show a first embodiment of the present invention. FIG. 1 is a longitudinal sectional view of a main part of an internal combustion engine, FIG. 2 is an enlarged sectional view taken along line 2-2 of FIG. 2 is an enlarged sectional view taken along line 3-3 of FIG. 1, and FIG. 4 is a sectional view taken along line 4-4 of FIG.

First, in FIG. 1, a combustion chamber 15 is formed between the upper surface of a piston slidably fitted to a cylinder block (not shown) and the cylinder head 14. A pair of intake valve ports 16... And a pair of exhaust valve ports 17
Are provided, the two intake valve ports 16 are connected to an intake port 18, and the two exhaust valve ports 17 are connected to an exhaust port 19.

[0016] As the intake valves V _I ... stem 20 ... are of the intake valve ports 16 ... individually openable pair of engine valves slidably fitted with the guide tube 21 ... to the respectively provided in the cylinder head 14 And retainers 22 provided at the upper ends of the stems 20 projecting upward from the respective guide cylinders 21.
A coil-shaped valve spring 23 which surrounds the respective stem 20 ... are provided between the cylinder head 14, with the intake valves V _I ... in a direction to close the intake valve ports 16 ... by their valve springs 23 ... Be inspired. The two exhaust valve ports 17 ... individually openable pair of exhaust valves V _E ... stems 24 ... of slidably fitted with the guide tube 25 ... to the respectively provided in the cylinder head 14, the guide tube Coiled valve springs 27 surrounding the stems 24 are provided between the cylinder head 14 and the retainers 26 provided at the upper end of the stems 24 projecting upward from the cylinders 25. 2
7, the exhaust valves V _E are biased in a direction to close the exhaust valve ports 17.

The two intake valves V _I and the two exhaust valves V _E.
Between them, a camshaft 2 parallel to the axis of a crankshaft (not shown)
8 are rotatably disposed so as to be positioned below the upper end and the upper end of both exhaust valves V _E ... of the intake valves V _I ..., 1 the cam shaft 28 at a reduction ratio of 1/2 And is linked to and connected to the crankshaft so as to rotate counterclockwise. Moreover, an oil bath 30 is formed on the upper surface of the cylinder head 14, and the cam shaft 28 is
The intake-side valve cam 29 _I and the exhaust-side valve cam 29 _{E provided} in the oil bath 8 are arranged at positions where they can be immersed in oil in the oil bath 30.

Both intake valves V_I… And the intake valve on the camshaft 28
Cam 29_IBetween the camshaft 28 and the intake valve
V_I… The intake-side valve train 31 that can be converted to the opening and closing movement of_IBut
Provided, both exhaust valves V_E... and the exhaust side movement of the camshaft 28
Valve cam 29_EExhaust the rotational movement of the camshaft 28
Valve V_EExhaust-side valve train 31 that can be converted to the opening and closing movement of ... _E
Is provided.

Exhaust side valve gear 31_EIs flat with the camshaft 28
Rocker arm shaft 32 that is fixedly arranged with a regular axis
And are rotatably supported by the rocker arm shaft 32 and
Ki valve V _E… And exhaust side valve cam 29_EProvided between
And a rocker arm 33. One end of rocker arm 33
The exhaust valve cam 29_ECam slipper 34 that contacts
The other end of the rocker arm 33 has two exhaust valves V
_E, A pair of tappet screws 35 respectively contacting the upper ends of
… Are screwed in, respectively, with adjustable advance / retreat positions.
You.

Referring also to FIGS. 2 and 3, the intake side
Valve train 31_IIs the power transmission means 36 ₁With
This power transmission means 36₁Can rotate around the axis
Sun gear 37 which is a large inner ring, and the same shaft as the sun gear 37
An outer ring surrounding the sun gear 37 so as to be rotatable around a line
A ring gear 38 and a plurality of planetary rotators
The gears 40 are connected to the sun gear 37 and the ring gear 38.
Supports rotation around an axis parallel to the axis
Of the planet gears 40 around the sun gear 37
Composed of a planetary gear type with a carrier 39 that rotates in conjunction with it
Is done.

The parallel power transmission means 36 _first sun gear 37 is a three components that constitute the, sun gear 37 of the ring gear 38 and carrier 39, the axis of the cam shaft 28 at a position offset from the axis of the cam shaft 28 And is provided coaxially and integrally with a rotating shaft 41 having a
1 is rotatably supported by a cylinder head 14.

The sun gear 37, which is one of the above components,
On both sides of the base 42a of the pair of connecting arms 42, 42 extending in the intake valves V _I ... side at a position spaced in the axial direction of the pivot shaft 41, 42a is fitted, are fixed, these the distal end portion of the connecting arm 42, 42 of the tappet screws 43, 43 that contact each stem 20 ... upper end of the intake valves V _I ... it is screwed respectively be adjustable forward and backward position. Thus, sun gear 37 is linked to the intake valves V _I ..., will be connected, the intake valves V _I ... it is opened and closed in response to the rotation of the sun gear 37.

A carrier 39, which is another component of the power transmission means 36, includes a pair of ring-shaped support plates rotatably supported by the bases 42a, 42a of the connecting arms 42, 42, respectively. 39a, 39a and the rotating shaft 41
A plurality of, e.g., six shafts 39b, 39b having both ends supported by both support plates 39a, 39a having an axis parallel to the
The planetary gear 40 meshes with the outer periphery of the sun gear 37 and the inner periphery of the ring gear 38 with the shafts 39b, 39b, ... arranged at equal intervals in the circumferential direction of the rotating shaft 41. , 40 ... are rotatably supported.

The two supporting plates 39a, 3 of the carrier 39
The 9a, the roller retaining arms 45 extending to the intake side valve operating cam 29 _I side, 45 is provided integrally, an inner surface and the support plates 39a of the rollers holding arms 45, 45, between the inner surface of 39a Are formed with step portions 45a, 45a. At the tips of the roller holding arms 45, 45, a disc-shaped bearing portion 4 is provided.
6 and 46 are provided integrally, and their bearing portions 4
A roller 44 longer than the entire length of the planetary gears 40 in the axial direction is supported between the gears 6 and 46. That is, both ends of a roller shaft 47 having an axis parallel to the axis of the rotating shaft 41 are fixed to the bearings 46, 46, and the roller 44 and the roller shaft 4.
7, a needle bearing 48 is interposed.

As shown by the solid lines in FIGS. 2 and 3, the support plate 39a, the roller holding arm 45 and the bearing 4
If the outer surface of the 6 is formed so as to be continuous and flush with, but workability is to be good, as shown by the two-dot chain line L ₁ in FIG. 2 and FIG. 3, the outer surface of the bearing portion 46 The thickness of the bearing portion 46 may be increased by being located outside of the outer side surface of the roller holding arm 45, so that the rigidity of the bearing portion 46 can be increased. and as indicated by the two-dot chain line L ₂ in FIG. 3, so as to reduce the wall thickness of the bearing portion 46 as the outer surface of the bearing portion 46 is located inward from the outer surface of the roller retaining arms 46 Well,
Then, the weight of the bearing portion 46 and thus the carrier 39 can be reduced.

[0026] with the width of the power transmitting means 36 ₁ in the axial direction of the cam shaft 28 to minimize achieved inertia weight reduction due to weight reduction of the power transmission unit 36 _1, also roller 44 and the intake side by the assembling error or the like due to the increase of the surface pressure by the contact area with the the part of the valve operating cam 29 _I is a non-contact state roller 44 and the intake-side valve operating cam 29 _I is smaller than the set value roller 44 In order to prevent uneven wear on the intake side valve cam 29 _I and
The width of the intake-side valve operating cam 29 _I along the axis direction of the cam shaft 28 is set larger than the axial length of the distance or roller 44 between the inner surfaces of the roller retaining arms 45, 45, the roller 4
The overall axial length of 4 to rolling contact with the intake-side valve operating cam 29 _I.

That is, the carrier 39 is linked and connected to the intake valve cam 29 _I of the camshaft 28, and the carrier 39 is rotated by the intake valve cam 29 _I in accordance with the rotation of the camshaft 28. It is driven dynamically.

Further, as shown in FIG. 4, the carrier 39 has six shafts 39 on a straight line SL connecting the center of the roller 44 and the center of the sun gear 37, that is, the center of the rotating shaft 41.
b are arranged so that one of the shafts 39b is arranged.

The outer periphery of the ring gear 38 and the roller 4
4 recess 45b than the tangent line TL connecting the outer periphery to allow the portion of the intake-side valve operating cam 29 _I enters into the inner side of the
But it is formed on the side surfaces of the valve operating cam 29 _I side of the rollers holding arms 45, 45. That is, as clearly shown in FIG. 4, on a projection onto a plane orthogonal to the axis of the camshaft 28, the rotation trajectory RT drawn by the tip of the intake valve cam 29 _I indicates the outer circumference of the ring gear 38 and the outer circumference of the roller 44. as intersect the tangent TL connecting the cam shaft 28 and the relative position of the power transmission means 36 ₁ is set, side i.e. the bottom side of the intake-side valve operating cam 29 _I side of the rollers holding arms 45, 45 a recess 45b that allows the entering part of the intake-side valve operating cam 29 _I ... are formed.

[0030] Incidentally, the side surface or upper side surface opposite to the intake side valve operating cam 29 _I the rollers holding arms 45, 45,
As shown by the solid line in FIG. 4, the workability is improved if formed along the tangent connecting the outer circumferences of the support plates 39 a, 39 a and the outer circumferences of the bearing portions 46, 46. as shown by the two-dot chain line L _3, the tangent may be formed to bulge outward than, it is possible to increase the rigidity of the rollers holding arms 45, 45 that way, two more of 4 as shown by the dash-dotted L _4, may be formed on the recessed inward side of the tangent, it is possible to reduce the weight of the rollers holding arms 45, 45 that way.

The ring gear 38 is a residual component of the three components forming the power transmitting means 36 _1,
The carrier 39 is rotatably supported. That is, both ends of the ring gear 38 formed in a cylindrical shape are connected to the carrier 3.
9, the two supporting plates 39a, 39a are rotatably supported by the inner peripheral edges thereof.
a, 39a, at both ends corresponding to the roller holding arms 45, 45, both ends of the ring gear 38 are supported by the support plates 39a, 3a.
9a and the roller holding arms 45, 45 are rotatably supported by step portions 45a, 45a formed between them.

The ring gear 38 is integrally provided with a control arm 49 extending in a direction perpendicular to the axis of the rotating shaft 41.
The head cover 52 is provided with a rotation position control means 51 having a control rod 50 that comes into contact with the control arm 49 in a direction substantially orthogonal to the control arm 49.
For example, the hydraulic pressure or the electromagnetic force is transmitted from the control rod 50 to the control arm 4.
9 can be applied, and the force applied from the control rod 50 to the control arm 49 can be changed steplessly by hydraulic control or electric control. In order to prevent the ring gear 38 from inclining with respect to the axis of the rotating shaft 41 due to the force acting on the control arm 49 from the control rod 50, the control arm 49 is provided with a rotating shaft. The ring gear 38 is integrally provided at the center of the ring gear 38 in the direction along the axis of 41, so that the rotation position control means 51 can apply a force to the ring gear 38 while avoiding an increase in the number of parts.

By the way, the carrier 39 by the roller retaining arms 45, 45 is pushed by the intake-side valve operating cam 29 _I
Rotates in the direction indicated by the arrow 53 in FIG.
Since a relatively large spring load of about 20kgf example by the valve springs 23 ... in the intake valves V _I ... and the sun gear 37 is acting, the ring gear 38 when the rotation of the ring gear 38 is not regulated in the arrow 53 and free to rotate in the same direction, there is no possibility that the intake valves V _I ... it is opened and closed. However, in the rotation of the ring gear 38 when it is controlled by the rotational position control means 51, the planetary gears 40 ... with rotation sun gear 37 is operated Tsutomu times, the intake valves V _I ... is opened actuated That is, by changing the rotational position of the ring gear 38 steplessly, the maximum lift amount and the valve opening period of the two intake valves V _I , that is, the operation characteristics can be changed steplessly.

[0034] Next, to explain the action of this first embodiment, the three components constituting the intake side valve operating device 31 _I smell 1, the power transmitting means 36 ₁ is a planetary gear type, i.e. the sun gear 37, ring gear 38 And carrier 39
Of which, the carrier 39 and the sun gear 37 are
8, the intake valve cam 29 _I and the intake valve V _I ...
Is connected, since the amount of rotation of the ring gear 38 is controlled steplessly pivoted position control means 51, can be made and finely control the intake valves V _I ... operating characteristics of the stepless.

Further power transmitting means 36 _1, three components i.e. the sun gear 37 that constitute the ring gear 3
8 and the carrier 39 is of a planetary gear type comprised disposed rotatably around the same axis, power transmitting means 36 _primary compaction i.e. the intake-side valve operating device 31 _I
Miniaturization can be achieved, and by the components 37, 38, 39 mutual meshing coupling forming the power transmitting means 36 _1, it is possible to accurately control the intake valves V _I ... operating characteristics of . Between the pair of connection arms 42 and 42 yet to be connected respectively to the intake valves V _I ..., the ring gear 38, since the planetary gear 40 ... and the carrier 39 are disposed, to be more compact and more power transmission means 36 ₁ it can.

[0036] In such a power transmitting means 36 _1,
The amount of rotation of the carrier 39 is significantly smaller than the amount of rotation of the sun gear 37, and the carrier 39 is interlocked with and linked to the intake valve cam 29 _I of the camshaft 28.
There interlocking the intake valves V _I ..., since it is intended to be connected, lift i.e. the sun gear 3 that is required by the intake valves V _I ...
It is possible to set the size of the intake side valve actuation cam 29 _I with respect to the amount of rotation of 7 to be significantly smaller. Therefore, the load received by the carrier 39 from the intake side valve operating cam 29 _{I can} be made relatively small to contribute to the reduction of the valve operating load, and the intake side valve operating cam 29 _I becomes relatively small. The space required for the rotation of the valve cam 29 _{I and} the space required for the operation of the roller holding arms 45 and 45 of the carrier 39 are also relatively small, so that the valve operating chamber in which the intake-side valve operating device 31 _I is arranged is made compact. Can be achieved.

Also formed on the upper surface of the cylinder head 14
Intake oil and exhaust side movement in the oil in the oil bath 30
Valve cam 29_I, 29_EIs squashed, so the intake side and
Exhaust valve cam 29_I, 29_EI'll scrape the oil with
Thus, the power transmission means 36 ₁Thoroughly lubricate the
Can be. At this time, the cam shaft 28 is turned counterclockwise in FIG.
By rotating, intake and exhaust side movement
Valve cam 29_I, 29_EPower transmission
Step 36₁To the power transmission means 36₁of
Lubrication can be performed more effectively.

The roller holding arm 4 connected to the carrier 39
The roller 44 supported between the tips of the rollers 5 and 45 moves on the intake side.
Valve cam 29_IRolling contact reduces valve load
The layer can be reduced. Moreover, both roller holding arms 45,
45 along the axial direction of the camshaft 28.
Air side valve cam 29_IIs smaller than the width of the camshaft 28
Transmission means 36 along the axial direction of₁As small as possible
Power transmission means 36 ₁Inertia weight reduction by weight reduction
The roller can be used even if there is an assembly error.
44 is provided on the intake valve cam 29 over its entire length in the axial direction._I
To maintain the set surface pressure,
And intake valve cam 29_ITo prevent uneven wear on
Can be stopped.

[0039] Additionally, the outer and than tangent TL connecting the outer periphery of the roller 44 allows the entering part of the intake-side valve operating cam 29 _I inwardly and the recesses 45b of the ring gear 38 ... is, both because it is formed on the side surface of the intake-side valve operating cam 29 _I side of the roller retaining arms 45, 45, while avoiding the interference of the intake-side valve operating cam 29 _I and the rollers holding arms 45, 45, the cam shaft 28 and the power the transmitting means 36 ₁ is as close as possible can be made compact intake-side valve operating device 31 _I and.

One of the six shafts 39b of the carrier 39 is arranged on a straight line SL connecting the center of the roller 44 and the center of the sun gear 37.
Both roller holding arms 45, 45 and both support plates 39a, 39
a can be reinforced by one shaft 39b, and the carrier 39 has sufficient strength without increasing the thickness of both support plates 39a, 39a and both roller holding arms 45, 45. so that it is, it can contribute to weight reduction i.e. weight reduction of the power transmitting means 36 ₁ and thus the intake-side valve operating device 31 _I carrier 39.

FIGS. 5 and 6 show a second embodiment of the present invention. FIG. 5 is a longitudinal sectional view of the power transmission means, and FIG. 6 is a sectional view taken along line 6-6 of FIG.

First, referring to FIG.
_2, the control arm and the sun gear 37 which is connected to the intake valves V _I ... (see FIG. 1), in conjunction with the intake-side valve operating cam 29 _I, a ring gear 38 which is connected, which is connected to the rotational position regulating means 51 With the carrier 39 having 49 ', it is configured as a planetary gear type.

The ring gear 38 includes an intake valve cam 29.
Roller holding arms 55 extending to the _I side are integrally provided, both ends of a roller shaft 47 are fixed between the tip portions of both roller holding arms 55. The roller shaft 4 is provided with a bearing 48 interposed.
It is rotatably supported at 7.

The cam shaft 28 is connected to both roller holding arms 55
Are arranged above the tip of the camshaft 28.
On the intake side valve operating cam 29 _I, the roller 44 is in rolling contact from below.

As shown by the solid line in FIG. 5, if the outer peripheral portion of the ring gear 38 facing the roller 44 is formed so as to be curved at the same curvature as the other outer peripheral portions of the ring gear 38, although the weight reduction is possible, may be linearly formed as shown by two-dot chain line L ₅ in FIG. 5, it is possible to improve the workability that way, two more of 5 as shown by the dash-dotted L _6,
It may be formed so as to be curved substantially corresponding to the outer periphery of the roller 44, so that the rigidity of the ring gear 38 can be increased.

The outer periphery of the ring gear 38 and the roller 4
A concave portion 55 that allows a part of the intake side valve actuation cam 29 _I to enter the inside of the tangent line TL connecting the outer circumferences of the intake valves 4.
a, 55a are the valve operating cams 2 of the roller holding arms 55, 55.
9 Formed on the _I side surface. That is, on a projection view on a plane perpendicular to the axis of the cam shaft 28, the intake valve cam 29 _I
Rotation locus RT which is drawn, so intersect the tangent TL connecting the outer periphery of the outer periphery and the roller 44 of the ring gear 38, the relative position of the cam shaft 28 and the power transmission unit 36 ₂ is set, both rollers holding arms 55 the ... side or upper side of the intake-side valve operating cam 29 _I side of the recess 55a that allows the entering part of the intake-side valve operating cam 29 _I, and 55a are provided, their recesses 55a, 55a is formed so as to open upward and the roller 44 side at the portion corresponding to the axial length of the intake-side valve operating cam 29 _I.

[0047] Incidentally, the side surface or upper side surface of the rollers holding arms 55 ... opposite to the intake side valve operating cam 29 _I of the first
As described in relation to the roller retaining arms 45, 45 integral with the carrier 39 in the embodiment, it may be a shape corresponding to the two-dot chain line L _3, L ₄ in FIG.

[0048] The second embodiment also can be made compact of the similar to the first embodiment, the intake-side valve operating device as much as possible to close the cam shaft 28 and the power transmission unit 36 _2.

Since the concave portions 55b, 55b provided on the upper side surfaces of the roller holding arms 55, 55 are formed to be open to the roller 44 side, the oil scattered in the valve operating chamber is reduced. The rotation resistance of the roller 44 can be reduced by being guided to the roller 44 side from 55b.

FIGS. 7 and 8 show a modification of the second embodiment. FIG. 7 is a longitudinal sectional view of the power transmission means, and FIG. 8 is a sectional view taken along line 8-8 of FIG.

In this modification, the cam shaft 28 is disposed further above the position shown in FIG.
5 and 55, the ring gear from the intake side valve operating cam 29 _I 38
The concave portions 55 a, 55 a provided on the upper surfaces of the roller holding arms 55, 55 can flow oil toward the ring gear 38. The ring gear 38 is provided with passages 57 for guiding the oil supplied from the concave portions 55a into the ring gear 38.

According to this modification, the concave portions 55a, 55a
The oil that has accumulated in the power transmission means 36 ₂
Also guided within, can be used for lubrication of the power transmitting means 36 _2.

As still another embodiment of the present invention, JP-A-5-33840, JP-A-5-79450,
JP-A-5-157149, JP-A-6-34005
It is also possible to use a planetary friction type power transmission means (traction drive) as disclosed in Japanese Patent Application Laid-Open No. 6-66360 and JP-A-6-66360 as the power transmission means. Further, the present invention can be applied to an exhaust valve as an engine valve.

Although the embodiments of the present invention have been described in detail, the present invention is not limited to the above embodiments, and various design changes can be made without departing from the present invention described in the appended claims. It is possible to do.

[0055]

As described above, according to the first aspect of the present invention, the first and second components of the power transmission means having the inner ring, the outer ring, and the carrier as the components are valve-operated cams. And the rotation position of the third component is controlled by the rotation position control means, so that the operating characteristics of the engine valve can be more finely controlled using compact power transmission means. It is possible to
Further, since the roller supported between the distal ends of the pair of roller holding arms connected to the outer race or the carrier is in rolling contact with the valve operating cam, the valve operating load can be reduced.
In addition, the distance between the inner surfaces of the two roller holding arms is made smaller than the width of the valve cam along the axial direction of the camshaft, so that the inertia weight of the power transmission means can be reduced, and the rollers and the valve cam can be reduced. Uneven wear can be prevented. In addition, the concave portion that allows a part of the valve operating cam to enter a part inward of a tangent connecting the outer periphery of the outer race and the outer periphery of the outer race and the outer periphery of the roller has a valve operating mechanism of the two roller holding arms. By being formed on the side surface on the cam side, the camshaft and the power transmission means can be brought as close as possible to make the valve train compact.

According to the second aspect of the present invention, the strength of the continuous portion of the two roller holding arms and the two support plates is reduced by one of a plurality of shafts.
And the carrier can have sufficient strength without increasing the thicknesses of both support plates and both roller holding arms, so that the weight of the carrier can be reduced, that is, the power transmission means, and thus the valve train. It can contribute to the conversion.

Further, according to the third aspect of the invention, the rotational resistance of the roller can be reduced by guiding the oil accumulated in the concave portion to the power transmission means side, particularly to the roller side.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a main part of an internal combustion engine according to a first embodiment.

FIG. 2 is an enlarged sectional view taken along line 2-2 of FIG.

FIG. 3 is an enlarged sectional view taken along line 3-3 of FIG. 1;

FIG. 4 is a sectional view taken along line 4-4 of FIG. 2;

FIG. 5 is a longitudinal sectional view of a power transmission means of a second embodiment.

FIG. 6 is a sectional view taken along line 6-6 in FIG. 5;

FIG. 7 is a longitudinal sectional view of a power transmission means according to a modification of the second embodiment.

FIG. 8 is a sectional view taken along line 8-8 in FIG. 7;

[Explanation of symbols]

28 ... camshaft 29 _I ... valve operating cam 31 _I ... valve operating device 36 ₁ , 36 ₂ ... power transmission means 37 ... sun gear as inner ring 38 ... ring gear 39 as outer ring ... Carrier 39a ... Support plate 39b ... Shaft 40 ... Planetary gear as planetary rotating body 44 ... Roller 45,55 ... Roller holding arm 45b, 55a ... Recess 51 ... - rotating position control means SL · · · straight TL · · · intake valve as the tangent V _I · · · engine valve

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Hidetoshi Oishi 1-4-1 Chuo, Wako, Saitama Prefecture Inside Honda R & D Co., Ltd. (72) Katsuaki Shiiki 1-4-1, Chuo, Wako, Saitama Honda R & D Co., Ltd.

Claims (3)

[Claims] An engine valve (V) according to an operating state of the engine._I)
In a valve train of an internal combustion engine capable of changing the operating characteristics of the internal combustion engine,
Valve operated cam (29_I) Is parallel to the camshaft (28)
Inner ring (37) rotatable about a simple axis, and the inner ring (3)
The inner ring (37) is made rotatable around the same axis as 7).
Outer ring (38) surrounding the inner ring (37) and outer ring
(38) The planetary rotator (40) arranged between the inner ring
Around an axis parallel to the axis of (37) and the outer ring (38)
The planetary rotator (40)
A cap that rotates in conjunction with the revolution around the inner ring (37)
The rear (39) is a component, and those components (3
7, 38, 39), the outer ring (38) and the carrier.
A) the first component (3
9) is the valve cam (29)_I) Linked to and linked to the
Outer ring (38) and component (37-39)
And the other of the carrier (39) or the inner ring (37)
The second component (37) defined as the engine valve
(V_I) Connected to the power transmission means (36)₁, 36_Two)
And the power transmission means (36₁, 36_Two)
(37-39) Rotational position of the third component (38)
A circuit coupled to the third component (38) to control the position
Moving position control means (51);
Arms (45, 55) are their roller holding arms (45, 5).
5) the distance between the inner side surfaces in the axial direction of the camshaft (28)
Valve cam (29)_I) Width smaller than before
From the first component (39, 38), the valve cam (2)
9 _I) Side of the roller holding arms (45, 55).
The valve cam (29)_IRolling contact
Roller (44) is supported by the outer ring (38).
And a tangent line (TL) connecting the outer circumference of the roller (44).
The valve cam (29_I) Partly enters
Recesses (45b, 55a) that allow
Valve cam (29) of roller holding arm (45, 55)_I) On the side
Valve train for internal combustion engine characterized by being formed on the side
Place. 2. The carrier (39) has a ring plate shape and a pair of support plates (39a) arranged at intervals in the rotation axis direction of the inner ring (37), and a rotation of the inner ring (37). A plurality of shafts (39b) having an axis parallel to the axis and provided between the support plates (39a) and rotatably supporting the respective planetary rotators (40).
a) on a straight line (SL) connecting the center of the roller (44) pivotally supported between the distal ends of the roller holding arms (45) integrally connected to the center of the inner ring (37); The valve train for an internal combustion engine according to claim 1, wherein one shaft (39b) of the plurality of shafts (39b) is arranged. 3. The valved cam (2), wherein the roller (44) is
9 _I ) is characterized in that the concave portions (55b) are provided on the upper side surfaces of both roller holding arms (55) arranged so as to be in rolling contact with the roller members from below and open to the upper side and the roller (44) side. The valve train for an internal combustion engine according to claim 1, wherein