JP3358852B2 - Valve train for internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to three or more cams provided on a camshaft with different profiles.
A plurality of cam followers, each of which is arranged so as to be able to swing around the same swing axis corresponding to each of the cams and at least one of which the engine valve is interlocked and connected, and along an axis parallel to the swing axis. An internal combustion engine having a plurality of connection / separation means each having a connection pin enabling a mutually independent switching operation between a connection position and a connection release position and having different combinations of cam followers connected by the connection pin. The present invention relates to a valve train.

[0002]

2. Description of the Related Art Conventionally, such a valve train is already known, for example, from Japanese Patent Application Laid-Open No. 63-57805.

[0003]

In the valve train disclosed in the above publication, three rocker arms are arranged adjacent to each other, and the connection and disconnection of two sets of rocker arms adjacent to each other are switched. By
The operating characteristics of the pair of engine valves are changed according to three operating states of the engine, a low-speed operating state, a medium-speed operating state, and a high-speed operating state. However, in this case, the operating characteristics of each engine valve are changed in two stages in the disconnected state and the connected state with the adjacent rocker arm, and the operating characteristics of the pair of engine valves are changed in three stages to operate the engine. The three-stage operation characteristic change according to the state is achieved. In order to enable more precise control of the valve operation characteristic change according to the engine operation state, the valve operation characteristic in each operation range is required. It is desirable to increase the degree of freedom in selecting combinations.

Accordingly, the present applicant has made all three cam followers adjacent to each other connectable by means of high-speed connection / separation means, and at the same time straddles the cam followers at the center in the arrangement direction and connects the cam followers on both sides with other connection / separation means. It is connectable, and linked to the cam follower at one end along the arrangement direction of each cam follower, the operating characteristics of the connected engine valve are changed in three stages, so that the degree of freedom in selecting the valve operating characteristics is increased. Proposed valve gear (Japanese Patent Application No. 4-24)
No. 6648). However, when the high-speed connection / separation means is in the uncoupled state and the other cam separation / following means is connected to the cam followers on both sides, the cam followers on both sides are connected across the cam follower at the center in the arrangement direction. Rigidity is relatively weak, and bounce tends to occur when the engine valve is seated.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a valve train for an internal combustion engine in which the degree of freedom in selecting valve operating characteristics is increased while increasing connection rigidity. I do.

[0006]

To achieve the above object of the Invention The invention of Claim 1 wherein the three or more cams provided on the camshaft at different flop Rofiru mutually, individually their cam A plurality of cam followers arranged so as to be able to swing around the same swing support shaft and to have at least one engine valve interlocked and connected thereto, and a connection along an axis parallel to the swing support shaft And a plurality of connection / separation means having different combinations of cam followers connected by the connection pins, the connection pins being capable of mutually independent switching operations between a position and a connection release position. In the valve device, the plurality of cams are provided on the camshaft by arranging a cam having a profile corresponding to a high-speed operation of the engine along the axis of the camshaft. High-speed connection / separation means capable of switching between a state in which all the cam followers are connected in a high-speed operation range of the Seki and a state in which the connection is released in a state other than the high-speed operation range; and another cam follower linked to and connected to the engine valve And one or a plurality of connection / separation means capable of switching between connection and disconnection are provided on the cam follower at positions different from each other in the circumferential direction of the pivot shaft, and all the members including the high-speed connection / separation means are provided. Is connected to the engine valve and is located at a position avoiding between the end of the connected cam follower on the engine valve side and the oscillation support shaft, as viewed from the outside in the axial direction of the oscillation support shaft. And the camshaft is disposed below the swing support shaft.
It is arranged directly above the cam provided on the camshaft,
A roller, which is arranged on the opposite side of the engine valve as viewed from the swing shaft and is coaxial with the connecting pin of the high-speed connecting / separating means and is in rolling contact with a cam corresponding to each cam follower, is supported by each of the cam followers. It is the fact that to said.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, reference examples and embodiments of the present invention will be described with reference to the drawings.

FIGS. 1 to 4 show a first reference example. FIG. 1 is a longitudinal sectional view taken along line 1-1 of FIG. 2, and FIG. 2 is an enlarged view of FIG. FIG. 3 is a plan view, and FIG.
FIG. 4 is an enlarged sectional view taken along line 4-4 in FIG.

First, in FIGS. 1 and 2, a cylinder head 11 in an SOHC type internal combustion engine has a combustion chamber 12
A pair of intake valve ports 13 are provided so as to open to the ceiling surface of the vehicle. The intake valves V ₁ , V ₂ as a pair of engine valves capable of individually opening and closing both intake valve ports 13 are respectively slidably fitted to a pair of guide cylinders 14 arranged on the cylinder head 11. Each intake valve V is provided between the cylinder head 11 and a retainer 15 fixed to the upper end of each intake valve V ₁ , V ₂ protruding from each guide cylinder 14.
_1, a coil-shaped valve spring 16 surrounding the V ₂ ... are interposed respectively, the intake valves V ₁ by their valve springs 16 ...,
V ₂ is biased upwardly i.e. closing direction.

Referring also to FIG. 3, both intake valves V ₁ , V
₂ and a camshaft 17 common to an exhaust valve (not shown) are interlocked and connected to a crankshaft (not shown) at a reduction ratio of 1/2. The camshaft 17 is connected to the cylinder head 11 and the cylinder The head 11 is rotatably supported by a plurality of holders 18 respectively coupled to the head 11.

The camshaft 17 has first, second and third cams 19, 20, and 2 having different profiles.
1 are provided in that order and spaced apart from one another. The first cam 19 has a profile for opening and closing both the engine valves V ₁ and V ₂ in the high-speed operation range of the engine, and has a constant base circle portion 19 a with a constant distance from the center of the cam shaft 17. And the base circle portion 19
and a high-order portion 19b extending radially outward from the upper portion 19a.
The second cam 20 is connected to one of the intake valves V _{1 in} a low speed operation range of the engine.
And has a profile for opening and closing both intake valves V ₁ and V ₂ in the middle speed operation range of the engine, and has a base circle having the same radius as the base circle portion 19 a of the first cam 19. The amount of outward projection of the camshaft 17 along the radial direction is made smaller than that of the high portion 19b of the first cam 19, and the high portion 19b
And a high-order portion 20b protruding from the base circle portion 20a over a narrower central angle range. The third cam 21 is designed with a profile for substantially dormant the other intake valve V ₂ in the low-speed operating range of the engine, the first
And the base circle portions 19a, 20a of the second cams 19, 20
Base circle portion 21a having the same radius as
The cams 19 and 20 have high portions 21b slightly protruding radially outward from the base circle portion 21a at positions corresponding to the high portions 19b and 20b.

First, second and third cams 19, 20, 2
1 has first, second, and third rocker arms 22, 23, 24 as cam followers that are individually driven, and the rocker arms 22, 23, 24
Is rockably supported by a rocker arm shaft 25 fixedly supported by a holder 20 while having an axis parallel to the camshaft 17 at a position obliquely above the camshaft 17.

The first rocker arm 22 extends from the rocker arm shaft 25 to the camshaft 17, and has a cam slipper 2 slidingly in contact with the first cam 19 at the lower end thereof.
6 is fixed. The second rocker arm 23 extends to both sides from the rocker arm shaft 25, and a cam slipper 27 slidingly contacting the second cam 20 is provided at a lower end of one end thereof.
A tappet screw 29 that is in contact with the upper end of _one intake valve V1 is screwed to the other end so that the screwing position thereof can be adjusted. The third rocker arm 24 extends from both sides of the rocker arm shaft 25. A cam slipper 28 slidingly in contact with the third cam 21 is fixedly provided at one lower end of the third rocker arm 24, and the other intake valve V is provided at the other end. _A tappet screw 29 abutting on the upper end of ₁ is screwed so that its screwing position can be adjusted. The first rocker arm 22 is resiliently biased by a resilient biasing means (not shown) in a direction in which the cam slipper 26 slides on the first cam 19.

By the way, as shown in Figure 2, to the intake valves V _1, V ₂ from the plane perpendicular to the axis of the cam shaft 17 through the widthwise center position of the second cam 20 along the axis of the camshaft 17 distance L _1, L ₂ of the are set to substantially the same. That is, from the second cam 20 to the second rocker arm 23
The distance from the point of application of the driving force to the intake valves V ₁ and V ₂ is set to be substantially equal.

The first to third rocker arms 22 to 24 include:
All of the rocker arm 22 to 24 high-speed connecting and separating means 30 ₁ couplable provided with high-speed operating range of the engine, first to
Intake valves V _1, V ₂ are linked each of the third rocker arm 22 to 24, the second and third rocker arms 23, 24 adjacent to each other are connected, for fast coupling and uncoupling of both 23 and 24 connecting separate switchable connecting and separating means 31 ₁ is provided with separating means 30 _1. Moreover, as shown in Figure 1, the connecting and separating means 31 _1, second and third rocker arms between the second and the axis and the cam 20, 21 of the swing axis i.e. the rocker arm shaft 25 of the third rocker arms 23, 24 while provided 23 and 24, the high-speed connecting and separating means 30 ₁ is first in a position in which the angle α deviation constituting substantially 90 degrees in the circumferential direction as the connecting and separating means 31 ₁ about the axis of the rocker arm shaft 25 The first to third rocker arms 22 to 24 are provided.

[0016] In FIG. 3, the connecting and separating means 31 _1, the second and third rocker arms 23, 24 can be operated to connect the connecting pin 32, the regulating member 3 for restricting the movement of the connecting pin 32
3 and a return spring 34 for urging the connecting pin 32 and the regulating member 33 to the uncoupling side.

The second rocker arm 23 is provided with a bottomed guide hole 35 opened to the third rocker arm 24 side in parallel with the rocker arm shaft 25. The connecting pin 32 is slidable in the guide hole 35. Fitted, connecting pin 3
A hydraulic chamber 36 is defined between one end of the second and the closed end of the guide hole 35. A hydraulic path 37 is provided in the rocker arm shaft 25, and a communication path 38 is provided in the second rocker arm 23 and the rocker arm shaft 25 so that the hydraulic path 37 always communicates with the hydraulic chamber 36 regardless of the swinging motion of the second rocker arm 23. Provided.

The third rocker arm 24 has a bottomed guide hole 39 corresponding to the guide hole 35 and is opened to the second rocker arm 23 side and is bored in parallel with the rocker arm shaft 25. A disc-shaped regulating member 33 slidably in contact with the end is slidably fitted in the guide hole 39.
An intermediate portion of the guide hole 39 is provided with a regulating step 39a which abuts on the regulating member 33 and regulates the moving end of the regulating member 33. The return spring 34 is provided with the closed end of the guide hole 39 and the regulating member. 33. Guide hole 39
The guide hole 40 coaxially and integrally connected to the regulating member 33 is movably inserted into the closed end of the insertion hole 4.
1 is provided.

In FIG. 4, the high-speed connection / separation means 30 ₁
A connecting pin 42 capable of connecting the first and second rocker arms 22 and 23, a restricting member 43 for restricting the movement of the connecting pin 42, and a return for urging the connecting pin 42 and the restricting member 43 to the uncoupling side. A spring 44, a connecting pin 45 capable of connecting the second and third rocker arms 23 and 24, a restricting member 46 for restricting the movement of the connecting pin 45, and a connecting pin 4
5 and a return spring 47 for urging the regulating member 46 to the uncoupling side.

The second rocker arm 23 has a guide hole 48 opened at both ends in parallel with the rocker arm shaft 25. The connecting pins 42 and 45 form a hydraulic chamber 49 between the two 42 and 45 to guide the second rocker arm 23. It is slidably fitted in the hole 48. The rocker arm shaft 25 in addition, the hydraulic passage 5, wherein the hydraulic passage 37 in the connecting and separating means 31 ₁ is isolated
The second rocker arm 23 and the rocker arm shaft 25 are provided with a communication passage 51 for communicating the hydraulic chamber 49 with the hydraulic passage 50 regardless of the swinging state of the second rocker arm 23.

A guide hole 52 having a bottom corresponding to the guide hole 48 is formed in the first rocker arm 22 so as to open toward the second rocker arm 23 and is formed in parallel with the rocker arm shaft 25. The disc-shaped regulating member 43 in contact is slidably fitted in the guide hole 52. An intermediate portion of the guide hole 52 is provided with a regulating step 52a which abuts on the regulating member 43 and regulates the moving end of the regulating member 43. The return spring 44 is provided with the closed end of the guide hole 52 and the regulating member. 43. At the closed end of the guide hole 52, an insertion hole 54 for movably inserting a guide rod 53 coaxially and integrally connected to the regulating member 43 is provided.

A guide hole 56 having a bottom corresponding to the guide hole 48 is formed in the third rocker arm 24 so as to open toward the second rocker arm 23 and is formed in parallel with the rocker arm shaft 25. The disc-shaped regulating member 46 in contact is slidably fitted in the guide hole 56. An intermediate portion of the guide hole 56 is provided with a regulating step 56a which abuts on the regulating member 46 and regulates the moving end of the regulating member 46. The return spring 47 is provided with the closed end of the guide hole 56 and the regulating member. It is contracted between 46. At the closed end of the guide hole 56, an insertion hole 58 for movably inserting a guide rod 57 coaxially and integrally connected to the regulating member 46 is provided.

By the way, the hydraulic paths 37 and 50 formed in the rocker arm shaft 25 are
Switching control valves 60, 61 capable of switching between a state in which the hydraulic pressure from the hydraulic pump 59 is applied to the pressure control valves 7, 50 and a state in which the hydraulic pressure in the hydraulic paths 37, 50 is released are connected to the switching control valves 60, 61. The switching operation of 61 is controlled by control means 62.
Is controlled by The control means 62 releases the hydraulic pressure of the hydraulic passages 37 and 50 in the low-speed operation range of the engine and releases the hydraulic pressure from the hydraulic pump 59 to the hydraulic passage 37 in the medium-speed operation range of the engine. But the hydraulic pressure in the hydraulic passage 50 is released, and in the high-speed operation range of the engine, both hydraulic passages 3
The switching operation of the two switching control valves 60 and 61 is controlled so that the hydraulic pressure from the hydraulic pump 59 acts on the switches 7 and 50 together.

Next, to explain the action of the first reference example, the high-speed connecting and separating means in the low-speed operating range of the engine 30 ₁
Hydraulic pressure in the hydraulic pressure chamber 36 is released in the hydraulic chamber 49 and the connecting and separating means 31 ₁ in. Thus, both the connecting pin is a high speed for connecting and separating means 30 ₁ 42,4
5 is moved to the hydraulic chamber 49 side by the spring force of the return springs 44 and 47 to the maximum extent.
Is located between the first and second rocker arms 22 and 23, and the contact surface of the connecting pin 45 and the regulating member 46 is the second contact surface.
And between the third rocker arms 23 and 24. Also In the connecting and separating means 31 _1, the connecting pin 32 is the return spring 3
By the spring force of 4, it has moved to the maximum to the hydraulic chamber 36 side,
The contact surface between the connecting pin 32 and the regulating member 33 is located between the second and third rocker arms 23 and 24. Therefore the first
-The third rocker arms 22, 23, 24 are in a state where relative angular displacement is possible.

[0025] In the connection release state of such high-speed connecting and separating means 30 ₁ and the connecting and separating means 31 _1, the second rocker arm 23 is swung by the second cam 20 by the rotation operation of the cam shaft 17, One intake valve V ₁ opens and closes at a timing and a lift according to the profile of the second cam 20. The third rocker arm 24 in sliding contact with the third cam 21 is in a state in which substantially rested its swung, it is possible to substantially closed resting the other intake valve V _2. Moreover, since the higher portion 21b which protrudes slightly in the third cam 21 is provided corresponding to the higher portion 20b of the second cam 20, the intake valve V ₂ is completely rather than closed rest, of one since the intake valve V ₁ is slightly operated in the opening direction when the valve opening, it is possible to prevent sticking to the valve seat of the intake valve V ₂ occurring when maintaining a fully closed state. Further, the first rocker arm 22 swings in accordance with the sliding contact with the first cam 19, but the swinging operation does not affect the second and third rocker arms 23 and 24 at all.

[0026] In the medium-speed operating range of the engine, the high-speed connecting and separating means 30 ₁ is in the decoupled state while the hydraulic pressure in the hydraulic pressure chamber 49 is released, but the connecting and separating means 31 ₁ of the hydraulic chamber 3
The hydraulic pressure from the hydraulic pump 59 is applied to 6.
As a result, in the connecting / separating means 31 ₁ , the connecting pin 32 is fitted into the guide hole 39 of the third rocker arm 24 against the spring force of the return spring 34, and the second and third rocker arms 2
3, 24 will be connected.

Thus, the second and third rocker arms 2
When the third rocker arm 3 and the second cam 20 are connected to each other, the third rocker arm 24 swings together with the second rocker arm 23 slidingly contacting the second cam 20, and the intake valves V ₁ and V ₂ correspond to the profile of the second cam 20. It can be opened and closed by the timing and lift amount.

[0028] At this time, the connecting and separating means 31 ₁ Since those connecting the second and third rocker arms 23, 24 adjacent to each other, the conventional which is adapted to couple across the other rocker arm existing between each other It is possible to make the connection rigidity relatively high as compared with that of the above. Second cam 2
Since the distance from the point of application of the driving force from 0 to the second rocker arm 23 to the two intake valves V ₁ and V ₂ is set to be substantially equal, the driving load from the second cam 20 is distributed almost evenly. It can act on both intake valves V ₁ and V ₂ , can avoid the occurrence of an eccentric load, prevent the cam slipper 27 from coming into contact with the second cam 20, and prevent the second cam 20.
In addition, uneven wear of the sliding surface of the cam slipper 27 can be prevented.

[0029] In the high-speed operating range of the engine, the hydraulic chamber 49 and the connecting and separating means at a high speed for connecting and separating means 30 ₁ 31
The hydraulic pressure from the hydraulic pump 59 is applied to the hydraulic chamber 36 at ₁ . Thus, in the high-speed connecting and separating means 30 _1, with between the first and second rocker arms 22, 23 connecting pin 42 is fitted in the guide hole 52 is connected, the connecting pin 45 is fitted into the guide hole 56 during the second and third rocker arms 23, 24 are connected Te, all of the rocker arm by the high-speed connecting and separating means 30 ₁ 22-2
4 are connected.

When all of the first to third rocker arms 22 to 24 are connected, the second and third rocker arms 23 and 24 connected to and linked to the intake valves V ₁ and V ₂ swing by the first cam 19. It swings with the first rocker arm 22 that is driven and driven, and the two intake valves V ₁ and V ₂
The opening and closing operation is performed at a timing and a lift amount according to the profile of No. 9.

[0031] In such a valve operating system, in the high speed operating range of the engine, not only all the rocker arms 22 to 24 are connected by a high-speed connecting and separating means 30 _1, by connecting and separating means 31 ₁ second Since the second and third rocker arms 23 and 24 are connected, the connection rigidity can be increased.

[0032] Moreover the connecting and separating means 30 ₁ and the connecting and separating means 31 ₁ for high speed, since it is intended to be disposed at a position displaced about the axis of the rocker arm shaft 25, a plurality of connecting and separating means 30 _1, 31 ₁ despite being disposed, can be obtained without increasing the width of the rocker arms 22 to 24 along the axis of the rocker arm shaft 25, a sufficient working stroke in both connecting and separating means 30 _1, 31 ₁ .

Further connecting and separating means 31 ₁ to become a consolidated state in the medium-speed operating range and the high-speed operating range of the engine, second and third in between the axis and the second and third cam 20, 21 of the rocker arm shaft 25 Since it is provided on the rocker arms 23 and 24, the second
And the third rocker arms 23 and 24 are connected, so that the connection rigidity can be further increased.

By the way, when all the rocker arms 22 to 24 are connected in the high-speed operation range of the engine, the first rocker arm 22 to 24 located at one end along the direction of arrangement is arranged.
The second and third rocker arms 23, 23 interlocked and connected to the intake valves V ₁ and V ₂ respectively by the rocker arm 22.
24 is oscillated, each rocker arm 22 to 24 is provided with the first rocker arm 2 from the first cam 19.
Direction load of twisting with respect to the virtual plane 63 the axis of the rocker arm shaft 25 in a (see FIG. 1) passing through the axis of the connecting and separating means 31 _first axis and the rocker arm shaft 25 located in the vicinity of the driving force acting point of the 2 When the torsion occurs, uneven wear occurs due to a single contact on the sliding contact surface between the cam slipper 26 of the first rocker arm 22 and the first cam 19. However, high-speed connecting and separating means 30 _1,
Since the connecting and separating means 31 ₁ about the axis of the rocker arm shaft 25 is provided on the rocker arm 22 to 24 at a position shifted by an angle α of approximately 90 degrees in the circumferential direction, connecting and separating means 30 ₁ is in the connection mode for high-speed As a result, the rigidity against the torsion is enhanced, and the occurrence of an uneven load on the sliding contact surface between the cam slipper 26 and the first cam 19 is prevented as much as possible.

[0035] FIG. 5 shows a modification of the first reference example, the parts corresponding to the first reference example of FIGS. 1-4 are denoted by the same reference numerals.

In the high speed operation range of the engine, all rocker arms 2
High speed connecting and separating means 30 ₂ connectable 2 to 24 includes a first connecting and separating mechanism 64 that can switch connection and uncoupling of the first and second rocker arms 22 and 24, second and third rocker arms 23, The second connection / separation mechanism 65 can switch the connection / disconnection of the 24 independently of the first connection / separation mechanism 64.

The first connection / separation mechanism 64 includes first and second
A connecting pin 42 capable of connecting the rocker arms 22 and 23,
The connecting member 42 includes a regulating member 43 for regulating the movement of the connecting pin 42, and a return spring 44 for urging the connecting pin 42 and the regulating member 43 to the uncoupling side. A connecting pin 45 for connecting the rocker arms 23 and 24, and a regulating member 4 for regulating the movement of the connecting pin 45;
6 and a return spring 47 for urging the connection pin 45 and the regulating member 46 toward the connection release side.

[0038] The second rocker arm 23, the guide hole 48 ₁ of the bottom that is open to the side first rocker arm 22 is parallel to drilled the rocker arm shaft 25, connecting pin 4
2 to form a hydraulic chamber 49 ₁ is slidably fitted in the guide holes 48 ₁ between the closed end of the guide hole 48 _1. In the rocker arm shaft 25, a connection switching means 31 is provided.
₁ (see FIG. 3), a hydraulic path 50 isolated from the hydraulic path 37
₁ is provided, on the second rocker arm 23 and the rocker arm shaft 25, the communication passage 51 ₁ for communicating is provided a hydraulic chamber 49 ₁ regardless swing state of the second rocker arm 23 to the hydraulic passage 50 _1.

Further to the second rocker arm 23 is a third rocker arm 24 of the open bottom on the side guide hole 48 ₂ is formed in the guide hole 48 ₁ coaxially connecting pin 4
5 to form a hydraulic chamber 49 ₂ is slidably fitted in the guide holes 48 ₂ between the closed end of the guide hole 48 _2. In the rocker arm shaft 25, the connection switching means 31 is provided.
_{1 and} the hydraulic path 50 ₁
And has hydraulic passage 50 ₂ that is isolated is provided in the partition wall member 66, the second rocker arm 23 and the rocker arm shaft 25, the hydraulic chamber 49 ₂ hydraulic passage 50 ₂ regardless swing state of the second rocker arm 23 communicating passage 51 ₂ which communicates is provided.

The hydraulic paths 37, 50 ₁ , and 50 ₂ formed in the rocker arm shaft 25 correspond to the hydraulic paths 3
Switching control valves 60, 6 capable of switching between a state in which hydraulic pressure from hydraulic pump 59 acts on 7, 50 ₁ , 50 ₂ and a state in which hydraulic pressures in hydraulic paths 37, 50 ₁ , 50 ₂ are released.
1 _1, 61 ₂ are connected, their switching control valve 6
0,61 _1, 61 ₂ of the switching operation is controlled by the control means 62. Condition Thus the control means 62 and, depending on the operating state of the engine, to act and a state to release all the hydraulic path 37,50 _1, 50 ₂ of the hydraulic, the hydraulic pressure from the hydraulic pump 59 only to the hydraulic passage 37 When, by switching between a state in which the action of hydraulic pressure only to the hydraulic passage 50 _1, and a state for applying a hydraulic pressure from all of the hydraulic path 37,50 _1, 50 ₂ to the hydraulic pump 59, the switching control valve 60, 61 ₁ and controls the switching operation of the 61 _2.

According to this modification, the connection of the first to third rocker arms 22 to 24 is released to make the opening / closing operation characteristic of the intake valve V ₁ according to the profile of the second cam 20 and the intake valve V ₂ In accordance with the profile of the third cam 21 and the second and third rocker arms 23,
24 and the opening and closing operation characteristics of both intake valves V ₁ and V ₂ according to the profile of the second cam 20, and the first and second rocker arms 21 and 22 are connected to connect the intake valve V ₁ the third opening and closing operation characteristics of the intake valves V ₂ as well as one corresponding opening and closing operating characteristics of the profile of the first cam 19
A state according to the profile of the cam 21 and a state where all the rocker arms 22 to 24 are connected to connect the two intake valves V ₁ , V
The _second opening and closing characteristic switchable between it and a state that one corresponding to the profile of the first cam 19 can be increased more freedom of choice of the valve operating characteristic.

[0042] Figure 6 to 9 show a second exemplary embodiment of the present invention, FIG. 6 is a sectional view along line 6-6 in FIG. 7 a longitudinal sectional view, 7 of FIG. 7 6 8 is an enlarged plan view taken along line -7, FIG. 8 is an enlarged sectional view taken along line 8-8 in FIG. 6, and FIG.
FIG. 10 is an enlarged sectional view taken along line -9, and the same reference numerals are given to portions corresponding to the first reference example.

First, in FIGS. 6 and 7, first to third
The rocker arm 22 to 24, all the rocker arms 22 to 24 high-speed connecting and separating means 30 ₃ connectable to provided a high-speed operating range of the engine, first through third rocker arms 22 to
24, the intake valves V ₁ and V ₂ are interlocked and connected to each other, and the second and third rocker arms 23 and 2 are adjacent to each other.
The 4, switchable connecting and separating means 31 ₂ is provided independently of the high speed connection separation means 30 ₃ coupling and uncoupling of both 23 and 24. Moreover, as shown in Figure 6, the high-speed connecting and separating means 30 _3, the first through third rocker arm between the axis and the cam 19 to 21 of the swing axis i.e. the rocker arm shaft 25 of the rocker arms 22 to 24 22-2
While it provided 4, connecting and separating means 31 ₂ second and at a position angle α deviation constituting substantially 90 degrees in the circumferential direction with the high speed connection separation means 30 ₃ about the axis of the rocker arm shaft 25 Three rocker arms 23 and 24 are provided.

In FIG. 8, the high-speed connection / separation means 30 ₃
A connecting pin 68 for connecting the third and second rocker arms 24 and 23, and a connecting pin 68 for connecting the second and first rocker arms 23 and 23;
A connecting pin 69 capable of connecting the connecting pins 22;
And a connecting pin 68, 69
Spring 7 for urging the regulating member 70 toward the connection release side
1 is provided.

The third rocker arm 24 is provided with a bottomed guide hole 72 opened to the second rocker arm 23 side in parallel with the rocker arm shaft 25, and the connecting pin 68 is slidably fitted in the guide hole 72. You. Moreover, the guide hole 72
A hydraulic chamber 73 is formed between the closed end of the locker arm and the connecting pin 68, and the hydraulic chamber 73 is connected to a hydraulic path 50 in the rocker arm shaft 25 through a communication path 74 provided in the third rocker arm 24 and the rocker arm shaft 25. You can always communicate.

A guide hole 75 corresponding to the guide hole 72 is provided in the second rocker arm 23 in parallel with the rocker arm shaft 25 with both ends opened, and a connecting pin 69 having one end slidably in contact with the connecting pin 68 is provided. It is slidably fitted in the guide hole 75.

A guide hole 76 corresponding to the guide hole 75 is formed in the first rocker arm 22.
A cylindrical regulating member 70 having a bottom and slidably contacting the connecting pin 69 is slidably fitted in the guide hole 76. A regulating member 70 is provided at an intermediate portion of the guide hole 76.
A restricting step 76a is provided for restricting the moving end of the restricting member 70 by abutting against the guide hole 7a.
6 is contracted between the retaining ring 77 fitted on the inner surface of the inner ring 6 and the regulating member 70.

[0048] In FIG. 9, the connecting and separating means 31 ₂ includes a connecting pin 80 capable of connecting the third and second rocker arms 24 and 23, regulating member 8 for regulating the movement of the connecting pin 80
1 and a return spring 82 for urging the connecting pin 80 and the regulating member 81 to the uncoupling side.

The third rocker arm 24 is provided with a bottomed guide hole 83 opened to the second rocker arm 24 side in parallel with the rocker arm shaft 25, and a connecting pin 80 is slidable in the guide hole 83. Mating, connecting pin 8
Hydraulic chamber 84 is defined between one end of O and the closed end of guide hole 83. The third rocker arm 23 and the rocker arm shaft 25 are provided with a communication passage 85 for allowing the hydraulic chamber 84 to always communicate with the hydraulic passage 37 in the rocker arm shaft 25.
Is provided.

A guide hole 86 corresponding to the guide hole 83 is formed in the second rocker arm 23.
5, a cylindrical regulating member 81 having a bottom and slidingly in contact with the connecting pin 80 is slidably fitted in the guide hole 86. A regulating member 81 is provided at an intermediate portion of the guide hole 86.
A restricting step 86a is provided for restricting the moving end of the restricting member 81 by contact with the guide hole 8a.
6 is contracted between the retaining ring 87 fitted on the inner surface of the inner ring 6 and the regulating member 81.

[0051] The second reference example as well the connecting and separating means 31 ₂ and the high-speed connecting and separating means 30 ₃ and the connecting release state in the low speed operating range of the engine, connecting state coupling separating means 31 ₂ in the medium-speed operating range of the engine Although the the uncoupled state connecting and separating means 30 ₃ for high speed, by allowed to both operatively connected to connecting and separating means 31 ₂ and the high-speed connecting and separating means 30 ₃ in the high-speed operating range of the engine, similarly to the first reference example The effect can be achieved.

Next, an embodiment of the present invention will be described with reference to FIG.
I will tell. This embodiment is based on the second reference example.
Therefore, only the differences will be described below. That is, this
In this embodiment, rollers 88... That are in rolling contact with the corresponding cams 19 to 21 are respectively supported on the rocker arms 22 to 24, and are accommodated coaxially in the rollers 88. 30 ₃ to each rocker arm 2
2 to 24 are arranged . Thus, the frictional force is reduced between the corresponding cam 19 to 21 and the rocker arms 22 to 24, Ru can contribute to the reduction of the valve driving force.

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.

For example, the positions of the second and third cams 22 and 23 may be interchanged.
A profile having a profile that substantially operates the intake valve may be used. Further, the present invention can be applied to a valve gear of an exhaust valve.

[0055]

As described above, according to the present invention, among the plurality of cams, a cam having a profile corresponding to a high-speed operation of the engine is disposed outside the camshaft along the axis of the camshaft. A high-speed connection / separation means for switching between a state in which all the cam followers are connected in a high-speed operation range of the engine and a state in which the connection is released in other than the high-speed operation range; Since one or a plurality of connection / separation means capable of switching connection / disconnection of another cam follower are disposed on the cam follower at positions different from each other in the circumferential direction of the swing support shaft, the valve operating characteristics can be freely selected. The connection rigidity can be increased when the cam follower is connected by the connection / separation means outside the high-speed operation range of the engine, and the connection / disconnection mechanism can be increased. Can the contributing to downsizing as possible to reduce the width of the entire cam follower along the swing shaft by causing shifting around the swing shaft of the cam followers. In addition, all of the above connection and separation means are interlocked with the engine valve as viewed from the outside of one end in the axial direction of the swing support shaft, to avoid a gap between the end of the connected cam follower on the engine valve side and the swing support shaft. Since it is arranged at the position, the space for disposing the parts such as the retainer for supporting the valve spring around the upper end of the engine valve can be sufficiently secured without being affected by the connection / separation means. It is possible to increase the degree of freedom of setting the lift amount between them, and furthermore, the part of the cam follower holding the connecting and separating means can be separated from the above-mentioned parts such as the retainer. Therefore, it is effective in preventing deformation of the cam follower, and can contribute to improvement in reliability of the switching operation of the connection / separation means.

[0056] Further mosquitoes especially Mushafuto is arranged below the rocking shaft, the high speed connection separation means and is arranged immediately above the cam provided on the camshaft, the swing support shaft When viewed from the opposite side of the engine valve, the roller which is disposed coaxially with the connecting pin of the high-speed connecting / separating means and is in rolling contact with the cam corresponding to each cam follower is pivotally supported by each cam follower. The high-speed connection / separation means and rollers can be arranged without difficulty by effectively utilizing the space above the camshaft arranged below the support shaft, contributing to downsizing of the valve operating mechanism in the height direction. In addition, the thickness of the portion of the cam follower that holds the high-speed connection / separation means can be sufficiently ensured, which is effective in preventing deformation of the portion. Therefore, the reliability of the switching operation of the high-speed connection / separation means can be improved. It can contribute to .

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a valve gear according to a first reference example, and FIG.
Sectional view along line 1-1

FIG. 2 is an enlarged plan view of FIG.

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

FIG. 4 is an enlarged sectional view taken along line 4-4 of FIG. 1;

FIG. 5 is a longitudinal sectional view corresponding to FIG. 4 of a modification of the first reference example;

6 is a longitudinal sectional view of a valve gear according to a second reference example, and FIG.
Sectional view along line 6-6

FIG. 7 is an enlarged plan view as viewed in the direction of arrow 7 in FIG. 6;

8 is an enlarged sectional view taken along line 8-8 of FIG. 6;

FIG. 9 is an enlarged sectional view taken along line 9-9 of FIG. 6;

FIG. 10 is a longitudinal sectional view showing an embodiment of the present invention and corresponding to FIG. 6;

[Explanation of symbols]

17 camshafts 19, 20, 21 ... cams 22, 23, 24 ... rocker arms 25 as cam followers 25 ... rocker arm shafts 30 ₁ , 30 ₂ , 30 ₃ ... High-speed connection / separation means 31 ₁ , 31 ₂ ... Connection / separation means 32, 42, 45, 68, 69, 80 ... Connection pin 62 ... Control means V ₁ , V ₂ ... Intake as an engine valve valve

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-292509 (JP, A) JP-A-64-41607 (JP, A) JP-A-6-93821 (JP, A) 127813 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) F01L 13/00 301 F01L 13/00 302

Claims (1)

(57) [Claims] 1. A three or more cams which the flop Rofiru was different from each other are provided on the camshaft (17) (19, 2
0, 21) and their cams (19, 20, 21), respectively, and are arranged so as to be swingable around the same swing support shaft (25), and at least one of the engine valves (V ₁ ,
V ₂ ) are linked and connected to a plurality of cam followers (22,
23, 24) and connecting pins (68, 69; 80) enabling switching operation independently between a connecting position and a disconnecting position along an axis parallel to the swing support shaft (25). And the connecting pins (68, 69; 8)
0) connected by cam followers (22, 23, 2)
A plurality of connection / separation means (3) with different combinations of (4)
0 ₃ ; 31 ₂ ), the plurality of cams (19, 20, 21) are provided with the cams (1).
9, 20, 21), the cam (19) having a profile corresponding to the high-speed operation range of the engine is arranged on the outer side along the axis of the camshaft (17), and is provided on the camshaft (17). All cam followers (22,23,
24) and a high-speed connection / separation means (3) capable of switching between a connection state and a connection release state other than in the high-speed operation range.
0 ₃ ) and the other cam followers (2) to the cam followers (23, 24) interlocked and connected with the engine valves (V ₁ , V ₂ ).
One or a plurality of connection / separation means (31 ₂ ) capable of switching connection / disconnection of the cam followers (22, 23, 23) at different positions in the circumferential direction of the swing support shaft (25). 24) and all the connection / separation means (3) including the high-speed connection / separation means (30 ₃ ).
0 ₃ , 31 ₂ ) are linked to the engine valves (V ₁ , V ₂ ) when viewed from the outside of one end in the axial direction of the swing support shaft (25). The camshaft (17) is disposed below the pivot shaft (25), and the camshaft (17) is disposed below the pivot shaft (25). High-speed connection / separation means (3
0 ₃ ) is a cam (19, 19) provided on the cam shaft (17).
While being disposed directly above the 20, 21), arranged on the opposite side to the engine valves as viewed from the swing shaft (25) (V _1, V _2), the high-speed connecting and separating means (30 ₃ ) Are arranged coaxially with the connection pins (68, 69) of each cam follower (2).
Cams (19, 20, 21) corresponding to (2, 23, 24)
Valve operating equipment of an internal combustion engine rolling contact with the roller (88) is characterized in that it is pivotally supported by the respective cam follower (22, 23, 24) on.