JPH0693820A - Valve system for internal combustion engine - Google Patents

Abstract

PURPOSE:To arrange a trigger mechanism while avoiding increasing the widths of three rocker arms along their swing axes, and arrange a roller followers coaxial with a coupling change-over mechanism. CONSTITUTION:A first rocker arm 171 adapted to follow up a cam, a second rocker arm 181 adapted to follow up a cam coping with an operating condition at a speed higher than that of the first mentioned cam, and a third rocker arm 191 adapted to be associated and coupled with an engine valve V2 are swingably journalled to a rocker shaft 241, a first coupling change-over means 30 which can couple and discouple between the third rocker arm 191 and the first rocker arm 171 and a second change-over means 311 which can couple and discouple between at least one of the first rocker arm 171 and the third rocker arm 191, and the second rocker arm 181, independent from the first change-over means 301 are arranged, being shifted from each other in the circumferential direction of the rocker arm shaft 241.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve operating system for an internal combustion engine, in which the operating characteristics of the engine valve can be changed according to the operating condition of the engine.

[0002]

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

[0003]

By the way, in the valve operating device disclosed in the above publication, three rocker arms are arranged adjacent to each other, and two rocker arms adjacent to each other are switched between connection and disconnection. By
The operating characteristics of the pair of engine valves are changed according to three operating states of the engine, which are a low speed operating state, a medium speed operating state, and a high speed operating state. However, in the above-mentioned conventional one, the connection switching means for connecting the adjacent rocker arms of one set and the connection switching means for connecting the adjacent rocker arms of the other set are coaxially arranged above each other. In order to secure the operating stroke of the connection switching means, the widths of the three rocker arms adjacent to each other along the swing axis line must be set relatively large, which leads to an increase in the size of the valve operating device and at the time of rocker arm connection. It is necessary to increase the strength of the rocker arm in order to secure the rigidity.

As disclosed in Japanese Patent Laid-Open No. 61-31611, there is a connection switching means provided with a trigger mechanism for restricting its operation timing. If the above-mentioned trigger mechanism is applied to the above-described conventional valve operating device disposed in the above, it is necessary to set the axial length of the connecting piston, which is a component of the connection switching means, to a relatively long value. The width along should be relatively large. Also fair 2
As disclosed in Japanese Laid-Open Patent Publication No. -50286, a rocker arm is driven by a cam via a roller follower in order to reduce frictional resistance with the cam, and connection switching means is arranged coaxially with the roller follower. But there is
In the above-mentioned conventional valve operating device in which the pair of connection switching means are coaxially arranged, if the connection switching means is coaxially arranged with the roller follower, the width of the rocker arm is secured in order to secure the space occupied by the roller followers. Must be increased.

The present invention has been made in view of the above circumstances, and is provided with a trigger mechanism or a roller coaxially with the connection switching mechanism while avoiding an increase in the width of the three rocker arms along the swing axis. An object of the present invention is to provide a valve operating device for an internal combustion engine that allows disposition of a follower.

[0006]

In order to achieve the above object, according to the invention of claim 1, a first cam follower follows.
A rocker arm, a second rocker arm that follows a cam corresponding to an operating state faster than the cam, and a third rocker arm that is interlocked with and linked to an engine valve are swingably supported on a rocker arm shaft, and a third rocker arm. And the first
First switchable connection and disconnection with rocker arm
The connection switching means and the second connection switching means capable of switching connection and disconnection between at least one of the first rocker arm and the third rocker arm and the second rocker arm independently of the first connection switching means include the rocker arm shaft. It is arranged at a position displaced in the circumferential direction.

According to the second aspect of the invention, in addition to the configuration of the first aspect of the invention, at least one of the first and second connection switching means exerts a spring force in the extension direction to expand and contract. A trigger plate that is configured to be movable and that can be actuated in a direction parallel to the axis of the rocker arm shaft, and that can engage and disengage the connection piston to regulate the actuation timing has a relative angular displacement with the rocker arm. It is possible to arrange.

Further, according to the invention of claim 3, in addition to the constitution of the invention of claim 1, first, second and third aspects are provided.
The rocker arm is provided with a roller follower that individually contacts the corresponding cam, and one of the first and second connection switching means is disposed coaxially with the roller follower.

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

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

First, referring to FIGS. 1 and 2, the SOHC type
Cylinder head H in an internal combustion engine _C1In the combustion chamber 11
A pair of intake valve openings 12 are installed to open on the ceiling surface of the
Be kicked. A pair of machines that can open and close both intake valve openings 12 individually
Intake valve V as a gate₁, V ₂Is the cylinder head H_C1
Slidably on a pair of guide cylinders 13 arranged in
Each intake valve fitted and protruding from each guide cylinder 13
V₁, V₂Retainers 14 fixed to the upper ends of the
And cylinder head H_C1Between each intake valve V₁, V₂To
Surrounding coil-shaped valve springs 15 are provided, respectively.
Each intake valve V₁, V₂Do not go up
That is, it is biased in the valve closing direction.

A camshaft 16 _{1, which} is common to both intake valves V ₁ and V ₂ and an exhaust valve (not shown), is linked and connected to a crankshaft (not shown) at a speed reduction ratio of 1/2. Between the shaft 16 ₁ and both intake valves V ₁ and V ₂ ,
First, second and third rocker arms 17 ₁ , 18 ₁ and 19 ₁ are provided to convert the rotational movement of the camshaft 16 ₁ into the opening / closing movement of the intake valves V ₁ and V ₂ .

Referring also to FIG. 3, the camshaft 16
₁ is rotatably supported by a cylinder head H _C and a plurality of holders 20 respectively coupled to the cylinder head H _C. The cam shaft 16 ₁ is integrally provided with a low speed cam 21, a high speed cam 22, and a raised portion 23 in this order side by side. Low speed cam 21, which has a shape for allowing opening and closing the intake valves V _1, V ₂ at medium speed operating range of the engine with allowed to opening and closing one of the intake valves V ₁ in a low speed operating range of the engine , Base circle part 21
a and a high-order portion 21b extending radially outward from the base circular portion 21a. The high-speed cam 22 has a shape for opening and closing both intake valves V ₁ and V ₂ in the high-speed operating range of the engine, and is located outside the base circular portion 22a and the camshaft 16 _{1 in} the radial direction. The amount of protrusion to one side is set to be larger than that of the high-level portion 21b of the low-speed cam 21, and the base circular portion 2 covers a wide range of center angles from the high-level portion 21b.
2a and the high-order part 22b overhanging. Further, the raised portion 23 is basically provided in the camshaft 16 so that the other intake valve V ₂ is substantially in a rest state in the low speed operation region of the engine.
_Although it is formed so as to have a substantially circular outer surface centering on the axis of ₁ , the protrusion that slightly protrudes at a position corresponding to the high positions 21b, 22b of the low speed cam 21 and the high speed cam 22. Section is provided.

[0014] The first rocker arm 1 to the intake valves V ₁ of the one
7 ₁ interlock, are connected, the other intake valve V ₂ third rocker arm 19 ₁ is linked, coupled, a second rocker arm 1
8 ₁ is allowed to be free of both intake valves V ₁ and V ₂ and is arranged adjacent to the first and third rocker arms 17 ₁ and 19 ₁ . Thus, each rocker arm 17 _{1 to} 19
₁ is rockably supported by a rocker arm shaft 24 ₁ fixedly supported by a holder 20 while having an axis parallel to the cam shaft 16 _{1 at} an obliquely upper position of the cam shaft 16 ₁ .

A cam slipper 25 slidably contacting the low speed cam 22 is provided below one end of the first rocker arm 17 ₁ .
A high speed cam 22 is provided under one end of the second rocker arm 18 _1.
A cam slipper 26 that is in sliding contact with the slipper 2 that slides in contact with the raised portion 23 is provided at the lower portion of the third rocker arm 19 _1.
7 is provided.

First and third rocker arms 17 ₁ and 19
Tappet screws 28, which come into contact with the upper ends of the intake valves V ₁ and V ₂ , are respectively screwed to the other end of _{1 so} as to freely move back and forth.
The intake valves V ₁ and V ₂ are opened and closed in response to the swinging operation of the first and third rocker arms 17 ₁ and 19 ₁ .

[0017] The second rocker arm 18 _1, by the elastic biasing means, not shown, is resiliently biased in a direction to sliding contact with the cam slipper 26 into the high-speed cam 22.

[0018] The first to third of the rocker arm 17 ₁ to 19 _1, the first and third rocker arms 17 _1, 19 both 17 ₁ between _1, 19 ₁ first connection switching that can switch connection and release of the A means 30 ₁ is provided, and the first to third rocker arms 17 ₁ to 18 ₁ can switch connection and disconnection of these 17 _{1 to} 19 ₁ independently of the first connection switching means 30 ₁ . The connection switching means 31 ₁ is provided around the axis of the rocker arm shaft 24 ₁ at a position deviated from the first connection switching means 30 ₁ .

Rocker arm shaft 24₁Than both intakes
Valve V₁, V₂First rocker arm 17 on the side₁In the second
Kuka Arm 18₁3rd rocker arm 19₁On the side
An extending connecting arm 29 is integrally provided.
29 and the third rocker arm 19 ₁Connection and disconnection with
And the first connection switching means 30 can be switched₁Is provided
It Also rocker arm shaft 24₁With regard to the first connection
Switching means 30₁1st to 3rd rocker arm 1 on the side opposite to
7₁, 18₁, 19₁The second connection switching means 31₁Is provided
To be

The first connection switching means 30 ₁ has a connection piston 32 capable of connecting the first rocker arm 17 ₁ and the third rocker arm 19 ₁ , a restriction member 33 for restricting the movement of the connection piston 32, the connection piston 32 and the restriction. Member 3
And a return spring 34 for urging 3 toward the connection release side.

In the connecting arm 29 of the first rocker arm 17 ₁ , a bottomed guide hole 35 opened to the side of the third rocker arm 19 ₁ is formed in parallel with the rocker arm shaft 24 _1, and is connected to this guide hole 35. The piston 32 is slidably fitted, and one end of the connecting piston 32 and the guide hole 35
A hydraulic chamber 36 is defined between the closed end and the closed end. In addition, the first rocker arm 17 ₁ has a communication passage 37 communicating with the hydraulic chamber 36.
And a hydraulic passage 38 communicating with a hydraulic supply source (not shown) is provided in the rocker arm shaft 24 _1. This hydraulic passage 38 is connected to the communication passage 37, that is, the hydraulic chamber regardless of the rocking state of the first rocker arm 17 _1. Always in communication with 36.

By the way, the connecting piston 32 is constructed so as to expand and contract by exerting a spring force in the extension direction, and is slidably fitted in the guide hole 35 while the closed end is exposed to the hydraulic chamber 36. It has a bottomed cylindrical body 41, a short cylindrical body 42 slidably fitted in the guide hole 35, and a spring 43 compressed between the bottomed cylindrical body 41 and the short cylindrical body 42. Moreover, when the open end is brought into contact with one end surface of the short cylindrical body 42, an annular first outer surface of the bottomed cylindrical body 41 is provided between the one end surface of the short cylindrical body 42 and the bottomed cylindrical body 41. An annular notch that forms the engagement groove 44 is provided. An annular second engagement groove 45 is provided on the outer periphery of the bottomed cylindrical body 41. Moreover, the set load of the spring 43 is set smaller than that of the return spring 34.

In the third rocker arm 19 ₁ , a bottomed guide hole 47 corresponding to the guide hole 35 is opened in parallel with the rocker arm shaft 24 ₁ so as to open to the side of the connecting arm 29. The bottomed cylindrical regulation member 33 that abuts the other end of the short cylindrical body 42 is slidably fitted in the guide hole 47. The restricting member 33 is arranged such that its open end faces the closed end side of the guide hole 47, and the brim portion 33 protruding outward in the radial direction at the open end.
a slides on the inner surface of the guide hole 47. The return spring 34 is
The connecting piston 32 and the restriction member 33, which are contracted between the closed end of the guide hole 47 and the closed end of the restriction member 33 and abut against each other by the spring force of the return spring 34, are directed toward the hydraulic chamber 36 side. Be energized. Moreover, the guide hole 47
A communication hole 48 for removing air and oil is provided at the closed end of the. Further, the regulating member 33 is provided on the inner surface of the guide hole 47.
A retaining ring 49 is fitted which abuts on the flange portion 33a and prevents the regulating member 33 from falling off the guide hole 47.

A trigger mechanism 51 for regulating the operation timing of the first connection switching means 30 ₁ is attached to the first connection switching means 30 1. The trigger mechanism 51 is provided with the first engagement groove 44 or the first engagement groove 44 in the connection piston 32. The position where the second engaging groove 45 is engaged to restrict the movement of the connecting piston 32, and the connecting state of the first engaging groove 44 or the second engaging groove 45 is released to move the connecting piston 32. The trigger plate 52 is provided so as to be capable of swinging relative to the rocker arms 17 _{1 to} 19 ₁ around the axis of the rocker arm shaft 24 ₁ between the positions allowing the above.

A slit 53 is provided on the upper portion of the first rocker arm 17 ₁ , and guide portions 54, 54 extending upward are formed so as to be continuous with both side surfaces of the slit 53. The slit 53 is formed so as to correspond to the first engaging groove 44 in a state where the bottomed cylindrical body 41 and the short cylindrical body 42 of the connecting piston 32 are maximally displaced toward the hydraulic chamber 36 as shown in FIG. The second engagement groove 45 is formed in the upper portion of the first rocker arm 17 ₁ , and the second engagement groove 45 has moved to the maximum in the direction in which the bottomed cylindrical body 41 and the short cylindrical body 42 that are in contact with each other are separated from the hydraulic chamber 36. It is provided on the outer periphery of the bottomed cylindrical body 41 so as to be positioned corresponding to the slit 53 in this state.

First rocker arm 17 ₁ and one holder 2
A cylindrical collar 55 is inserted into the rocker arm shaft 24 ₁ between 0 and 0, and a cylindrical collar 56 is inserted into the rocker arm shaft 24 ₁ between the other holder 20 and the third rocker arm 19 _1. , Their colors 55,5
6, the movement of the rocker arms 17 _{1 to} 19 ₁ along the rocker arm shaft 24 ₁ is restricted.

The trigger plate 52 is provided with the one collar 55.
Is rotatably supported relative to. In this trigger plate 52,
An engaging plate portion 52a is provided integrally with the guide portions 54, 54 so as to slidably contact both surfaces thereof and engage with the first engaging groove 44 or the second engaging groove 45 from the slit 53 in a disengageable manner.

[0028] On the side of the holder 20 facing the first rocker arm 17 ₁ of the rocker arms 17 ₁ to 19 ₁ on both sides of the holder 20, 20, the stopper pin 57 is implanted toward the first rocker arm 17 ₁ side A stopper 52b that can come into contact with the stopper pin 57 from below is projected from the trigger plate 52. Further, one end of a torsion spring 58 surrounding the collar 55 is locked to the stopper pin 57, and the other end of the torsion spring 58 is locked to the trigger plate 52 from above. Thus, the trigger plate 52 is urged by the torsion spring 58 in the direction to bring the stopper 52b into contact with the stopper pin 57, and the first rocker arm 17 ₁ is stationary while the stopper 52b is in contact with the stopper pin 57. When it is in the state, the engagement plate portion 52a of the trigger plate 52 has the slit 5
3 can be engaged with the engaging grooves 54, 55, and when the first rocker arm 17 ₁ swings in the valve opening direction, the engaging plate portion 52
stopper pin 57 so that a is separated from the slit 53.
The position of is set.

In FIG. 4, the second connection switching means 31
₁Is the first and second rocker arms 17 ₁, 18₁A series
Connectable connecting piston 61 and second and third rocker arms
Form 18 ₁, 19₁And a connecting pin 62 capable of connecting
Regulation for regulating movement of piston 61 and connecting pin 62
Member 63, connecting piston 61, connecting pin 62 and ruler
And a return spring 64 for urging the control member 63 toward the connection release side.
Get

The first rocker arm 17 ₁ is provided with a bottomed guide hole 65 open to the second rocker arm 18 ₁ side in parallel with the rocker arm shaft 24 ₁ , and the connecting piston 61 slides in the guide hole 65. A hydraulic chamber 66 is defined between the one end of the connecting piston 61 and the closed end of the guide hole 65. Further, a communication passage 67 communicating with the hydraulic chamber 66 is bored in the first rocker arm 17 ₁ . Further, a hydraulic passage 68, which is isolated from the hydraulic passage 38 of the first connection switching means 30 ₁ and communicates with a hydraulic supply source (not shown), is formed in the rocker arm shaft 24 ₁ .
The hydraulic passage 68 always communicates with the communication passage 67, that is, the hydraulic chamber 66, regardless of the swinging state of the first rocker arm 17 ₁ .

The second rocker arm 18 ₁ has a guide hole 6
The guide hole 70 corresponding to No. 5 is the rocker arm shaft 24.
A connecting pin 62, which is formed parallel to ₁ and extends between both side surfaces and one end of which abuts against the other end of the connecting piston 61, is slidably fitted in the guide hole 70.

[0032] The third rocker arm 19 _1, the guide hole bottomed guide hole 71 corresponding to 70 are parallel bored with the rocker arm shaft 24 ₁ is opened to the second rocker arm 18 ₁ side, connecting pins A bottomed cylindrical regulating member 63 that abuts the other end of 62 is slidably fitted in the guide hole 71. The regulating member 63 has an opening end with a guide hole 7
It is arranged toward the closed end side of No. 1 and the flange portion 63a that projects outward in the radial direction at the open end of the guide hole 7 is formed.
Sliding contact with the inner surface of 1. The return spring 64 is provided between the closed end of the guide hole 71 and the closed end of the restricting member 63, and the connecting piston 61, the connecting pin 62, and the restricting member 63 are in contact with each other by the spring force of the return spring 64. Is urged toward the hydraulic chamber 66 side. Moreover, the closed end of the guide hole 71 is provided with a communication hole 72 for removing air and oil. Further, on the inner surface of the guide hole 71, a retaining ring 73 that is in contact with the flange portion 63a of the regulation member 63 and prevents the regulation member 63 from falling off the guide hole 71 is fitted.

Next, the operation of the first embodiment will be described. In the low speed operation range of the engine, the hydraulic pressures in the hydraulic chambers 36 and 66 in the first and second connection switching means 30 ₁ and 31 ₁ are released. In the 1-connection switching means 30 ₁ , the connection piston 32 is moved to the hydraulic chamber 36 by the spring force of the return spring 34.
In the second connection switching means 31 ₁ , the connection piston 61 and the connection pin 62 have been moved to the hydraulic chamber 66 side to the maximum extent. Is in a state. At this time, the first engagement groove 44 is formed in the first connection switching means 30 ₁ ,
The trigger plate 52 is engaged with the first engagement groove 44 when the first rocker arm 17 ₁ is stationary. Further, the contact surfaces of the connecting piston 32 and the regulating member 33 are located at positions corresponding to the connecting arm 29 and the third rocker arm 19 ₁ which are integral with the first rocker arm 17 ₁ . On the other hand, in the second connection switching means 31 ₁ , the contact surfaces of the connection piston 61 and the connection pin 62 are between the first and second rocker arms 17 ₁ and 18 ₁ , so that the connection pin 62 and the restriction member 63 come into contact with each other. The tangent surface lies between the second and third rocker arms 18 ₁ , 19 ₁ . Therefore, the first to third rocker arms 17 ₁ , 18 ₁ and 19 ₁ are in a state capable of relative angular displacement.

Such first and second connection switching means 3
In the uncoupled state of 0 ₁ and 30 ₂ , the first rocker arm 17 ₁ swings in response to the sliding contact with the low speed cam 21 due to the rotational operation of the cam shaft 16 ₁ , and one intake valve V ₁
Opens and closes at a timing and a lift amount according to the shape of the low speed cam 21. Further, the third rocker arm 19 ₁ slidingly in contact with the raised portion 23 is in a state in which its swinging operation is substantially stopped, and the other intake valve V ₂ can be substantially closed and stopped. Moreover, since the protruding portion 23 is provided with a slightly projecting portion corresponding to the high-order portions 21b and 22b of the low speed cam 21 and the high speed cam 22, the intake valve V ₂ is completely closed. Not one intake valve V
_{Since the} valve ₁ slightly operates in the valve opening direction when the valve ₁ opens, it is possible to prevent the intake valve V _{2 from} sticking to the valve seat, which occurs when the valve is completely closed. Further, the second rocker arm 18 ₁ swings in response to the sliding contact with the high speed cam 22, but the swinging motion is performed by the first and third rocker arms 1 1.
It has no effect on 7 ₁ , 19 ₁ .

In the medium speed operation range of the engine, the second connection switching means 31 ₁ is in the disconnection state while the hydraulic pressure in the hydraulic chamber 66 remains open, but the second connection switching means 31 ₁ is in the hydraulic chamber 36 of the first connection switching means 30 _1. High hydraulic pressure is supplied. As a result, in the first connection switching means 30 ₁ , the connection piston 32 tries to move in the direction of increasing the volume of the hydraulic chamber 36 against the spring force of the return spring 34. However, when the first rocker arm 17 ₁ is in the stationary state, the trigger plate 52 is engaged with the first engagement groove 44 and the movement of the connecting piston 32 is blocked. Thus, when the first rocker arm 17 ₁ starts to operate in the valve opening direction, the engaging plate portion 52b of the trigger plate 52 is disengaged from the first engaging groove 44 and the connecting piston 32 can be moved. 32 moves slightly to the 3rd rocker arm 19 ₁ side, and the 1st engaging groove 44 shifts from the position corresponding to the slit 53. Therefore, the first rocker arm 17
_{Even if 1} operates in the valve closing direction, the trigger plate 52 causes the first engaging groove 4 to move.
4 will not be engaged.

In this way, when the axes of the guide holes 35 and 47 coincide with each other, that is, the rocker arms 17 _{1 to} 19
_{When the 1} enters the stationary state, the connecting piston 32 fits into the guide hole 47, and the first and third rocker arms 17 ₁ ,
19 ₁ is in a connected state. In this state, the second engagement groove 45 is at a position corresponding to the slit 53, and the trigger plate 52 engages with the second engagement groove 45 when the first rocker arm 17 ₁ is in the stationary state.

When the first and third rocker arms 17 ₁ and 19 ₁ are connected as described above, the third rocker arm 19 ₁ swings together with the first rocker arm 17 ₁ slidingly contacting the low speed cam 21, and both The intake valves V ₁ and V ₂ are opened / closed at a timing and a lift amount according to the shape of the low speed cam 21.

In the high speed operation range of the engine, high hydraulic pressure is applied to the hydraulic chambers 36 and 66 of the first and second connection switching means 30 ₁ and 31 ₁ . As a result, the first connection switching means 30 ₁ maintains the connected state. Further, in the hydraulic chamber 66 of the second connection switching means 31 _1, an oil pressure that presses the connection piston 61 is generated against the spring force of the return spring 64, and the axis of the guide hole 65, the guide hole 70, and the guide hole 71. , The connecting piston 61 is fitted in the guide hole 70, and the connecting pin 62 is fitted in the guide hole 71.
The third rocker arms 17 _{1 to} 19 ₁ are in the connected state.

When the first to third rocker arms 17 _{1 to} 19 ₁ are connected, the first and third rocker arms 17 ₁ and 19 ₁ interlockingly connected to the intake valves V ₁ and V ₂ are connected to the high speed cam. Since it swings together with the second rocker arm 18 ₁ swingably driven by 22, the intake valves V ₁ and V ₂ are opened and closed at the timing and lift amount according to the shape of the high speed cam 22.

It should be noted that in the high speed operation range described above, the second connection
Switching means 31₁After the connection state is established, the first connection switching means 3
0₁To release the hydraulic pressure from the hydraulic chamber 36 of the first connection switching means
Thirty ₁May be in a decoupled state.

By the way, when the engine is changed from the high speed operation range to the low speed operation range or after the connection state of the second connection switching means 31 ₁ is established in the high speed operation area, the hydraulic chamber 36 in the first connection switching means 30 ₁ is When the hydraulic pressure of the connection piston 32 is released, the connecting piston 32 is pressed by the spring force of the return spring 34.
Although it is pushed to the side, when the first rocker arm 17 ₁ is in the stationary state, the trigger plate 52 is engaged with the second engagement groove 45 and the movement is blocked. Thus, the first rocker arm 1
When ₇₁ begins to swing in the opening direction, the trigger plate 52 second
First, the bottomed cylindrical body 41 is moved to the hydraulic chamber 36 side by being released from the engagement groove 45 and by the spring force of the spring 43. In this case, the short cylindrical body 42 does not return to the guide hole 35 by frictional force between the guide hole 35, 47 accompanying the swinging of the ₁ first rocker arm 17, to the first rocker arm 17 ₁ then becomes quiescent Accordingly, it returns to the guide hole 35, and the connection state of the first and third rocker arms 17 ₁ and 19 ₁ is released. In the second connection switching means 31 ₁ , the connecting piston 61 returns to the guide hole 65 and the connecting pin 62 returns to the guide hole 70 in the state where the axes of the guide hole 65, the guide hole 70, and the guide hole 71 are aligned. The state is released.

As described above, in the low speed operation range of the engine, one intake valve V ₁ is opened and closed at the timing and lift amount corresponding to the shape of the low speed cam 21, and the other intake valve V ₂ is substantially driven. It is possible to reduce fuel consumption by temporarily stopping the valve, and in the medium speed operation range of the engine, both intake valves V ₁ and V ₂ are adjusted in timing and lift amount according to the shape of the low speed cam 21. It becomes possible to obtain an output torque according to the medium speed operation by opening and closing with, and in the high speed operation range of the engine, both the intake valves V ₁ and V ₂ have timings corresponding to the shape of the high speed cam 22 and It is possible to improve the engine output by opening and closing with the lift amount, and it is possible to obtain the valve operating characteristics corresponding to the low speed, medium speed and high speed operating ranges of the engine.

Moreover, since the intake valve V _{2 which} is interlocked and connected to the third rocker arm 19 ₁ can be connected to the first rocker arm 17 ₁ while straddling the second rocker arm 18 ₁ , the low speed operating range of the engine can be achieved. It is possible to change the operating characteristics in three stages, namely, the valve closing is substantially stopped, the open / close operation is performed by the low speed cam 21 in the medium speed operation range of the engine, and the open / close operation is performed by the high speed cam 22 in the high operation range of the engine. Rocker arm 17
_The opening / closing operation by the low speed cam 21 and the opening / closing operation by the high speed cam 22 of the intake valve V ₁ linked and linked to ₁
In combination with the stepwise operation characteristic change, the degree of freedom in selecting the operation characteristics of the intake valves V ₁ and V ₂ according to the engine operating state can be increased.

In such a valve operating system, the second rocker arm 18 ₁ slidably contacting the high speed cam 22 includes a pair of intake valves V ₁ ,
Since it is arranged between the first and third rocker arms 17 ₁ and 19 ₁ which are individually interlocked and connected to V ₂ , the high speed cam 2
The driving load from 2 is distributed almost evenly and both intake valves V ₁ ,
It is possible to act on V ₂ and avoid the occurrence of unbalanced loads.

By the way, the connecting piston 32 of the first connection switching means 30 ₁ engages the trigger plate 52 of the trigger mechanism 51 in a disengageable manner, so that the bottomed cylindrical body 4 facing the hydraulic chamber 36.
1, the short cylindrical body 42, and the spring 43 compressed between the bottomed cylindrical body 41 and the short cylindrical body 42 are configured to exert a spring force in the extending direction and to be expandable and contractable. The axial length is relatively long. Thus, the first and second
The connection switching means 30 ₁ and 31 ₁ are rocker arm shafts 2.
The first connection switching means 30 ₁ is arranged so as to be displaced around the axis line of the third rocker arm 19 ₁ and the connection arm 29 extending from the first rocker arm 17 ₁ toward the third rocker arm 19 ₁ side. It is provided between and. Therefore, without increasing the width of the first rocker arm 17 ₁ along the axis of the rocker arm shaft 24 ₁ , the length required for the connecting piston 32 in the first rocker arm 17 ₁ can be secured, and the trigger mechanism 51 allows the first The connection switching means 30 ₁ can be operated at an accurate timing. Further, without increasing the width of each rocker arm 17 ₁ , 18 ₁ , 19 ₁ along the axis of the rocker arm shaft 24 ₁ , the first and second connection switching means 3
A sufficient operating stroke can be obtained with 0 ₁ and 31 ₁ , and the rigidity when the rocker arms 17 _{1 to} 19 ₁ are connected can be increased.

FIG. 5 shows a modification of the first embodiment, in which the first connection switching means 30 _1, which can be operated independently of the second connection switching means 31 ₁ , is the low speed of the first rocker arm 17 ₁ . The central angle α formed with the load acting point from the cam 21 is 90
It is provided between the first and third rocker arms 17 ₁ and 19 ₁ at a position close to a degree.

By the way, when the first connection switching means 30 ₁ is in the connected state, the first rocker arm 17 ₁ drives the third rocker arm 19 ₁ to swing. Therefore, the first rocker arm 17 ₁ has the first and second locker arms 17 _1. Third rocker arm 1
7 ₁ , 19 ₁ connection point and rocker arm shaft 24
A rotating moment about a straight line connecting the axis of _{1 at} a right angle acts. However, as described above, the first connection switching mechanism 30 ₁ is arranged at a position such that the central angle α of the first rocker arm 17 ₁ with the load acting point from the low speed cam 21 is close to 90 degrees. As a result, the rotation moment is increased by the cam slipper 25 of the first rocker arm 17 _1.
Occurs on a plane substantially parallel to the sliding contact surface between the low-speed cam 21 and the low-speed cam 21, and an unbalanced load is prevented from occurring on the sliding contact surface between the cam slipper 25 and the low-speed cam 21.

6 to 9 show a second embodiment of the present invention. FIG. 6 is a vertical sectional view taken along line 6-6 of FIG. 7, and FIG. 7 is a sectional view of FIG. FIG. 8 is an enlarged plan view taken along line -7, FIG. 8 is an enlarged sectional view taken along line 8-8 of FIG. 6, and FIG.
FIG. 9 is an enlarged cross-sectional view taken along line -9, in which parts corresponding to those in the first embodiment are designated by the same reference numerals.

First, referring to FIGS. 6 and 7, the DOHC type
Cylinder head H in an internal combustion engine _C2Can be opened and closed
Paired intake valve V supported₁, V₂And the camshaft 16
₂Between the camshaft 16₂The rotary motion of the intake valve
V₁, V₂The first, second and
3 rocker arm 17₂, 18₂, 19₂Is installed.

Referring also to FIG. 8, the camshaft 16
₂ , a medium speed cam 75, a high speed cam 22, and a low speed cam 21 are integrally provided side by side in this order. The medium speed cam 75 opens and closes one of the intake valves V ₁ in the low speed operation range of the engine, and both intake valves V ₁ and V ₁ in the middle speed operation range.
It has a shape for opening and closing V ₂ , and has a base circular portion 75a and a high-order portion 75b protruding outward in the radial direction from the base circular portion 75a. Moreover, the high-order portion 75b makes the amount of protrusion of the cam shaft 16 ₂ outward in the radial direction larger than the high-order portion 21b of the low-speed cam 21 and smaller than the high-order portion 22b of the high-speed cam 22, and the high-order portion 21b It is extended from the base circular part 75a so as to cover a wider central angle range than the higher part 22b.

One intake valve V ₁ has a first rocker arm 1
One end of 7 ₂ is interlocked and connected, one end of the third rocker arm 19 ₂ is interlocked and connected to the other intake valve V ₂ , and the second rocker arm 18 ₂ is connected to the first and third rocker arms 1 2.
It is arranged between 7 ₂ and 19 ₂ . Thus to the rocker arms 17 _{2-19 2} is swingably supported by the rocker arm shaft 24 ₂ having an axis parallel to the cam shaft 16 ₂ obliquely lower position of the cam shaft 16 _2.

[0052] The first to third of the rocker arm 17 ₂ to 19 _2, first and third rocker arms 17 _2, 19 both 17 ₂ Between ₂ and 19 ₂ first connection switching that can switch connection and release of the means 30 ₂ is provided in the first through third rocker arms 17 ₂ to 18 _2, they 17 _2-19 first coupling and uncoupling of the _two coupling switching means 30 ₂ second possible independently switching the The connection switching means 31 ₂ is provided around the axis of the rocker arm shaft 24 ₂ at a position deviated from the first connection switching means 30 ₂ .

Referring also to FIG. 9, on the opposite side of the rocker arm shaft 24 _{2 from} both intake valves V ₁ and V ₂ ,
The first and third rocker arms 17 ₂ and 19 ₂ have a second
Connecting arms 7 facing each other across the rocker arm 18 _2.
6, 77 are integrally provided, and these connecting arms 7
A first connection switching means 30 ₂ is provided between 6 and 77. Further, the first and third rocker arms 17 ₂ and 19 ₂ are interlocked with the intake valves V ₁ and V _2, and the first to third rocker arms 17 ₂ and 18 are connected between the connection position and the rocker arm shaft 24 _2.
Second connection switching means 31 ₂ is provided at ₂ , 19 ₂ .

The first connection switching means 30 ₂ includes connection arms 76,
Connecting piston 82 capable of connecting 77 and connecting piston 8
2 and the connecting member 82 for restricting the movement of the connecting piston 82
And a return spring 8 for urging the regulating member 83 toward the connection release side.
4 and.

A connecting arm 76 of the first rocker arm 17 ₂ ;
Guide holes 85, 89 corresponding to each other are formed in the connecting arm 77 of the third rocker arm 19 _{2 and} the rocker arm shaft 24.
Drilled in parallel with ₂ .

The connecting piston 82 is slidably fitted in the guide hole 85, and a hydraulic chamber 86 is defined between the connecting piston 82 and the closed end of the guide hole 85. Further, a communication passage 87 communicating with the hydraulic chamber 86 is bored in the first rocker arm 17 _2, and a hydraulic passage 88 communicating with a hydraulic supply source (not shown) is provided in the rocker arm shaft 24 ₂ , and the hydraulic passage 88 is the first hydraulic passage. Regardless of the rocking state of the rocker arm 17 _2, the rocker arm 17 ₂ is always in communication with the communication passage 87, that is, the hydraulic chamber 86.

The bottomed cylindrical regulating member 83 has a guide hole 89.
Is slidably fitted in the guide hole 89 of the regulating member 83.
From the retaining ring 9 fitted on the inner surface of the guide hole 89.
Blocked by 0. The return spring 84 is contracted between the closed end of the guide hole 89 and the regulating member 83, and
A communication hole 91 for removing air and oil is provided at the closed end of the.

By the way, the first to third rocker arms 17 ₂
To 19 _2, which follows the respective cam 75,22,21 via the roller follower 92, 93, 94, each roller follower 92 to 94, the rocker arm shaft 24 ₂
And each intake valve V ₁ , V ₂ between each rocker arm 17 ₂ ~
19 ₂ . The second rocker arm 18 ₂
The roller follower 93 is elastically biased in a direction in which the roller follower 93 is brought into sliding contact with the high speed cam 22 by an elastic biasing means (not shown).

The roller follower 92 has an axis parallel to the rocker arm shaft 24 ₂ and has the first rocker arm 17
_A plurality of rollers 97 are provided between an inner ring 95 fitted and fixed to the _{second member 2} and an outer ring 96 which is in sliding contact with the medium speed cam 75. The roller follower 93 is a rocker arm shaft 24.
_A plurality of rollers 100 are provided between an inner ring 98 having an axis parallel to ₂ and fitted and fixed to the second rocker arm 18 ₂ and an outer ring 99 slidingly contacting the high speed cam 22.
The roller follower 94 has an axis parallel to the rocker arm shaft 24 ₂ and is fitted into the third rocker arm 19 ₂ and fixed to the inner ring 101, and the outer ring 102 slidably contacting the low speed cam 21 has a plurality of rollers 103. Is installed. Moreover, each inner ring 95, 98, 101 is attached to each rocker arm 17
_{When 2 to} 19 ₂ are in a stationary state, they are fitted and fixed to the rocker arms 17 _{2 to} 19 ₂ so as to be aligned on the same axis.

The second connection switching means 31 ₂ has a connection piston 105 capable of connecting the first and second rocker arms 17 ₂ and 18 ₂ and the second and third rocker arms 18 ₂ and 19 ₂ .
A connecting pin 106 capable of connecting ₂ and a connecting piston 105
And a regulating member 107 for regulating the movement of the connecting pin 106
And a return spring 108 for urging the connecting piston 105, the connecting pin 106, and the regulating member 107 toward the connection releasing side.

The connecting piston 105 is the roller follower 92.
Slidably fitted to the inner ring 95 of the connecting piston 105
Between the first rocker arm 17 ₂ and one end of the hydraulic chamber 109.
Is defined. Further, a communication passage 110 communicating with the hydraulic chamber 109 is bored in the first rocker arm 17 ₂ . Further, in the rocker arm shaft 24 ₂ , the first connection switching means 30
_A hydraulic passage 112, which is isolated from the hydraulic passage 87 of ₁ and communicates with a hydraulic supply source (not shown), is provided. The hydraulic passage 112 has the communication passage 110 regardless of the swinging state of the first rocker arm 17 _2. That is, the hydraulic chamber 109
Always communicate with.

The connecting pin 106, one end of which abuts against the other end of the connecting piston 105, is slidably fitted to the inner ring 98 of the roller follower 93.

The bottomed cylindrical regulating member 107 that abuts the other end of the connecting pin 106 is an inner ring 101 of the roller follower 94.
The return spring 108 is contracted between the third rocker arm 19 ₂ and the restriction member 107. A communication hole 113 coaxial with the inner ring 101 is bored in the third rocker arm 19 ₂ .

In this second embodiment, in the low speed operation range of the engine
Is the first and second connection switching means 30 ₂, 31₂Is a connection solution
And the intake valve V on one side is released.₁Is the shape of the medium speed cam 75
Open and close with timing and lift according to the condition.
While the other intake valve V₂Of the low speed cam 21
Open and close with timing and lift according to the shape.
Can be Also, in the medium speed operation range of the engine, the first connection switching means
Thirty₂While the second connection switching means 3 is connected.
1₂Remains in the disconnected state, and both intake valves V ₁, V₂
Are both timing and timing according to the shape of the medium speed cam 75.
It can be opened and closed depending on the lift amount. Further institutional high speed
In the operating range, at least the second connection switching means 31₂Is connected
Both intake valves V₁, V₂Is the shape of the high-speed cam 22
Opening and closing at the timing and lift amount according to
Be done.

Therefore, the opening / closing operation characteristics of the intake valves V ₁ and V ₂ are changed according to the low speed, medium speed and high speed operating ranges of the engine to reduce the fuel consumption in the low operating range and the engine output in the entire operating range. It is possible to improve. Moreover, since the intake valve V _{2 which} is interlocked and connected to the third rocker arm 19 ₂ can be connected to the first rocker arm 17 ₂ across the second rocker arm 18 ₂ , the intake valve V ₂ is for low speed operation in the low speed operation range of the engine. The opening / closing operation by the cam 21, the opening / closing operation by the medium speed cam 75 in the medium speed operation range of the engine, and the opening / closing operation by the high speed cam 22 in the high speed operation range of the engine can be changed in three stages. 17 ₂ to interlock, in combination with opening and closing operations as well as the two-stage operating characteristics change of the opening and closing operation by the high-speed cam 22 by the quick cam 75 in a linked intake valves V _1, operating characteristics of the intake valves V _1, V ₂ It is possible to increase the degree of freedom in selection of changes according to the engine operating state.

The first and second connection switching means 30₂，
31₂Rocker arm shaft 24 ₂Shifted in the circumferential direction
Since it is placed, it is possible to connect and connect the adjacent rocker arms.
A pair of connection switching means that can switch connection / disconnection are arranged coaxially
Each rocker arm 17₂~ 1
9₂The second station without increasing the width along the swing axis of
Connection switching means 31₂Connecting piston 105, connecting piston
The shaft length of the connector 106 and the restriction member 107 is set to be relatively long.
can do. Therefore, each rocker arm 17₂
~ 19₂Second connection switching means without increasing the width of the
31₂Arrange the roller followers 92 to 94 coaxially with
Each cam 75, 22, 21 and each rocker arm 17₂~ 19
₂It reduces frictional resistance with the valve and contributes to reduction of valve power.
You can

FIG. 10 shows a third embodiment of the present invention.
Yes, in the SOHC internal combustion engine, the intake valve V₁In a row
The first roller that is moved and connected and that is slidably contacted with the low speed cam
Kuka Arm 17₁And intake valve V₂When linked and linked
Both slide against the ridge to obtain the valve resting state.
3rd Rocker Arm 19₁Between the high speed cam
The second rocker arm 18 to be touched₁Are placed, the first and
And the third rocker arm 17 ₁, 19₁First connection switching hand
Step 30₁And second and third rocker arms
18₁, 19₁In between, the first series in the second embodiment
Connection switching means 30₂A second series having basically the same configuration as
Connection switching means 31₃Is provided.

Thus, by setting both connection switching means 30 ₁ and 31 ₃ in the disconnection state in the low speed operation range of the engine, one intake valve V ₁ is driven by the low speed cam and the other intake valve 1 ₂ is driven. Are substantially stopped, and both the intake valves V ₁ and V ₂ are opened / closed by the low speed cam by setting only the first connection switching means 30 ₁ to the connected state in the medium speed operation range. Both the intake valves V ₁ and V ₂ can be opened and closed by the high speed cam by setting the first and second connection switching means 30 ₁ and 31 ₃ to the connected state.

FIG. 11 shows a fourth embodiment of the present invention.
Yes, in the SOHC internal combustion engine, the intake valve V₁In a row
The first roller that is moved and connected and that is slidably contacted with the low speed cam
Kuka Arm 17₁And intake valve V₂When linked and linked
Both slide against the ridge to obtain the valve resting state.
3rd Rocker Arm 19₁Between the high speed cam
The second rocker arm 18 to be touched₁Are placed, the first and
And the third rocker arm 17 ₁, 19₁First connection switching hand
Step 30₁But also the first and second rocker arms 17₁，
18₁Second connection switching means 31₃Is provided.

Thus, by setting both connection switching means 30 ₁ and 31 ₃ in the disconnection state in the low speed operation range of the engine, one intake valve V ₁ is driven by the low speed cam and the other intake valve 1 ₂ Are substantially stopped, and both the intake valves V ₁ and V ₂ are opened / closed by the low speed cam by setting only the first connection switching means 30 ₁ to the connected state in the medium speed operation range. Both intake valves V ₁ and V ₂ can be opened / closed by the high speed cam by setting both the first and second connection switching means 30 ₁ and 31 ₄ to the connected state.

FIG. 12 shows a fifth embodiment of the present invention. In a DOHC type internal combustion engine, a first rocker arm 17 ₂ which is slidably contacted with a medium speed cam and is interlocked with and linked to an intake valve V ₁ And a third rocker arm 19 ₂ interlockingly linked to the intake valve V ₁ and slidably contacting the low speed cam, a second rocker arm 18 slidably contacting the high speed cam.
₂ are arranged and the first and third rocker arms 17 ₂ , 1
9 first connection switching means 30 ₂ between ₂ and first and second rocker arms 17 _2, 18 second connection switching means 3 between ₂
1 ₃ are provided.

In the fifth embodiment, the intake valve V ₁ is opened and closed by the medium speed cam and the intake valve V ₁ is opened and closed by setting the connection switching means 30 ₂ , 31 ₃ in the disconnection state in the low speed operation range of the engine. V ₂ is opened / closed by the low speed cam and both the intake valves V ₁ and V ₂ are opened / closed by the medium speed cam by setting only the first connection switching means 30 ₂ in the medium speed operation range. By setting both the first and second connection switching means 30 ₂ and 31 ₃ in the high speed operation range, the intake valves V ₁ and V ₂ can be both opened and closed by the high speed cam.

FIG. 13 shows a sixth embodiment of the present invention. In a DOHC type internal combustion engine, a first rocker arm 17 ₂ which is slidably contacted with a medium speed cam and is interlocked with and linked to an intake valve V ₁ And a third rocker arm 19 ₂ which is interlocked with and linked to the intake valve V ₁ and slidably contacts the low speed cam, the first connection switching means 30 ₂ is provided between the third rocker arm 19 ₂ and the high speed cam. First and third rocker arms 17
_2, 19 second rocker arm 18 is disposed between _{2 2} and the second connection switching means 31 ₃ between the third rocker arm 19 ₂
May be provided.

Further, as in the seventh embodiment shown in FIG.
In the DOHC type internal combustion engine, the single intake valve V is interlocked with and linked to the third rocker arm 19 ₂ at a position corresponding to the second rocker arm 18 ₂ slidingly contacting the high speed cam, and the first and third rocker arms 17 ₂ , 19 are connected. The first connection switching means 30 ₂ between the _two , the first and second rocker arms 17 ₂ ,
A second connection switching means 31 ₃ may be provided between 18 ₂ .

According to the seventh embodiment, the engine operates at a low speed.
Both connection switching means 30 in the area₂, 31₃To disconnect
This allows the intake valve V to be opened and closed by the low speed cam.
Therefore, in the medium speed operation range, the first connection switching means 30₂Only connected
State, the intake valve V is opened and closed by the medium speed cam.
First, in the high speed operation range, the first and second connection switching means 3
0₂, 31₃Intake valve by connecting both
The V can be opened and closed by a high speed cam. Only
Is also linked to the intake valve V, and is connected to the third rocker arm 19 ₂
The second rocker arm 18 in which the rocking is driven by a high speed cam.₂
The high speed cam in the high speed operation area
To second rocker arm 18₂Point of load on the intake valve
It is possible to bring the load action point on V close to it, and
Occurrence can be avoided as much as possible.

FIG. 15 shows an eighth embodiment of the present invention, in which a first rocker arm 17 ₂ slidably contacting a medium speed cam.
And a third rocker arm 19 ₂ which is interlocked and connected to the intake valve V and slidably contacts the low speed cam, the first connection switching means 30 ₂ is provided between the third rocker arm 19 ₂ and the third speed rocker arm 19 ₂ . The second rocker arm 18 ₂ and the third rocker arm 1 arranged between the first and third rocker arms 17 ₂ and 19 _2.
The second connection switching means 31 ₃ may be provided between the second connection switching means 31 ₃ and 9 ₂ .

FIG. 16 shows a ninth embodiment of the present invention, in which a medium speed cam is provided on both sides of a third rocker arm 19 ₃ which is interlocked with and connected to the intake valve V and is slidably contacted with the low speed cam. in conjunction with the intake valve V with the sliding contact, the first rocker arm 17 ₃ to be connected, a second rocker arm 18 ₃ which is in sliding contact with the high-speed cam is disposed in the first and second rocker arms 17 _3, 19 First connection switching means 30 ₂ capable of switching connection and disconnection of ₃ and _second connection switching means capable of switching connection and disconnection of the first, second and third rocker arms 17 ₃ , 18 ₃ , 19 _3. 31 ₂ are arranged at positions displaced in the circumferential direction of the rocker arm shaft 24 ₂ .

According to this ninth embodiment, the engine operates at a low speed.
Both connection switching means 30 in the area₂, 31 ₂Is disconnected
Therefore, the intake valve V should be opened and closed by the low speed cam.
In the medium speed operation range of the engine, the first connection switching means 30₂Are
In the closed state, the intake valve V is opened and closed by the medium speed cam.
In the high speed operation range of the engine, the second connection switching means 31₂Are
In the closed state, the intake valve VH high-speed cam opens and closes.
To be

Further, as in the tenth embodiment shown in FIG. 17, the third rocker arm 19 ₄ slidably contacting the low speed cam and the first rocker arm 17 ₄ slidably contacting the medium speed cam.
Connection switching means 3 capable of switching connection and disconnection of
0 _2, third rocker arm 19 which is in sliding contact with the high-speed cam
_{The fourth} and third rocker arms 19 ₄ and the second connection switching means 30 ₃ capable of switching connection and disconnection of the rocker arm shafts 24 ₂ may be provided at positions displaced in the circumferential direction of the rocker arm shafts 24 ₂ .

Although the embodiments of the present invention have been described in detail above, 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 claims. It is possible to do.

For example, the present invention can be applied to a valve operating device for an exhaust valve.

[0082]

As described above, according to the first aspect of the invention, the first rocker arm that follows the cam, the second rocker arm that follows the cam corresponding to an operating state faster than the cam, and the engine valve A third rocker arm that is interlocked with and connected to the rocker arm shaft so as to be swingable, and a first connection switching means that can switch connection and disconnection between the third rocker arm and the first rocker arm; a first rocker arm; At least one of the third rocker arm and the second rocker arm is provided at a position displaced in the circumferential direction of the rocker arm shaft, with a second connection switching means capable of switching connection and disconnection independently of the first connection switching means. Because it is done
It is possible to secure a sufficient operation stroke of each connection switching means while keeping the width of each rocker arm along the swing axis relatively small, and also to dispose the trigger mechanism and change the connection while keeping the width small. It is possible to arrange the mechanism coaxially with the roller followers, and it is possible to reduce the size of the valve train and to ensure sufficient rigidity when the rocker arms are connected.

According to the invention described in claim 2, in addition to the structure of the invention described in claim 1, at least one of the first and second connection switching means exerts a spring force in the extension direction to expand and contract. A trigger plate that is configured to be movable and that can be actuated in a direction parallel to the axis of the rocker arm shaft, and that can engage and disengage the connection piston to regulate the actuation timing has a relative angular displacement with the rocker arm. The connection switching mechanism can be operated at a precise timing to ensure reliable operation.

According to the third aspect of the present invention, in addition to the structure of the first aspect of the invention, the first, second and third rocker arms have roller followers respectively contacting the corresponding cams. Is provided, and either one of the first and second connection switching means is disposed coaxially with the roller follower, so that it is possible to reduce friction loss and reduce valve operating power while avoiding an increase in the size of the rocker arm. be able to.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a first embodiment when applied to an intake valve side valve operating device of an SOHC type internal combustion engine, which is 1-1 of FIG.
It is sectional drawing which follows the line.

FIG. 2 is an enlarged plan view taken along the arrow 2 in FIG.

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

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

FIG. 5 is a vertical sectional view corresponding to FIG. 1 of a modified example of the first embodiment.

6 is a vertical cross-sectional view of the second embodiment when applied to the intake valve side valve operating system of the DOHC type internal combustion engine, and 6-6 in FIG.
It is sectional drawing which follows the line.

FIG. 7 is an enlarged plan view taken along line 7-7 of FIG.

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

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

FIG. 10 is a simplified plan view of the third embodiment.

FIG. 11 is a simplified plan view of the fourth embodiment.

FIG. 12 is a simplified plan view of the fifth embodiment.

FIG. 13 is a simplified plan view of the sixth embodiment.

FIG. 14 is a simplified plan view of the seventh embodiment.

FIG. 15 is a simplified plan view of the eighth embodiment.

FIG. 16 is a simplified plan view of the ninth embodiment.

FIG. 17 is a simplified plan view of the tenth embodiment.

[Explanation of symbols]

17 _{1 to} 17 ₄ ... 1st rocker arm 18 ₁ to 18 ₄ ... 2nd rocker arm 19 _{1 to} 19 ₄ ... 3rd rocker arm 21 ... low speed cam 22 ... high speed cam 24 ₁ , 24 ₂ ... rocker arm Shaft 30 ₁ , 30 ₂ ...... First connection switching means 31 ₁ , 31 ₂ , 31 ₃ ... Second connection switching means 32 ...... Connection piston 52 ...... Trigger plate 75 ...... Middle speed cam 92, 93, 94 ... … Roller followers V, V ₂ …… Intake valves as engine valves

[Procedure amendment]

[Submission date] August 6, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0013

[Correction method] Change

[Correction content]

Referring also to FIG. 3, the camshaft 16
₁ is rotatably supported by a cylinder head H _C1 and a plurality of holders 20 respectively coupled to the cylinder head H _C1 . The cam shaft 16 ₁ is integrally provided with a low speed cam 21, a high speed cam 22, and a raised portion 23 in this order side by side. Low speed cam 21, which has a shape for allowing opening and closing the intake valves V _1, V ₂ at medium speed operating range of the engine with allowed to opening and closing one of the intake valves V ₁ in a low speed operating range of the engine , Base circle part 21
a and a high-order portion 21b extending radially outward from the base circular portion 21a. The high-speed cam 22 has a shape for opening and closing both intake valves V ₁ and V ₂ in the high-speed operating range of the engine, and is located outside the base circular portion 22a and the camshaft 16 _{1 in} the radial direction. The amount of protrusion to one side is set to be larger than that of the high-level portion 21b of the low-speed cam 21, and the base circular portion 2 covers a wide range of center angles from the high-level portion 21b.
2a and the high-order part 22b overhanging. Further, the raised portion 23 is basically provided in the camshaft 16 so that the other intake valve V ₂ is substantially in a rest state in the low speed operation region of the engine.
_Although it is formed so as to have a substantially circular outer surface centering on the axis of ₁ , the protrusion that slightly protrudes at a position corresponding to the high positions 21b, 22b of the low speed cam 21 and the high speed cam 22. Section is provided.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0018

[Correction method] Change

[Correction content]

[0018] The first to third of the rocker arm 17 ₁ to 19 _1, the first and third rocker arms 17 _1, 19 both 17 ₁ between _1, 19 ₁ first connection switching that can switch connection and release of the means 30 ₁ is provided in the first through third rocker arm 17 ₁ to 1 9 _1, the possible independently of switching from those 17 _1-19 coupling and uncoupling the first connection switching means 30 ₁ of ₁ The 2-connection switching means 31 ₁ is provided at a position deviated from the first connection switching means 30 ₁ around the axis of the rocker arm shaft 24 ₁ .

[Procedure 3]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 1

[Correction method] Change

[Correction content]

[Figure 1]

[Procedure amendment 4]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 5

[Correction method] Change

[Correction content]

[Figure 5]

Front page continuation (72) Inventor Shoichi Kinoshita 1-4-1 Chuo, Wako-shi, Saitama, Ltd. Honda R & D Co., Ltd. (72) Inventor Shigemasa Kajiwara 1-4-1 Chuo, Wako-shi, Saitama Stock Incorporated Honda Technical Research Institute (72) Inventor Susumu Toki 1-4-1 Chuo 1-4 Wako City Saitama Stock Ltd. Honda Technical Research Institute

Claims (3)

[Claims] 1. An engine valve (V₂, V) operating characteristics of the engine
A valve operating system for an internal combustion engine that can be changed according to operating conditions
, The first rocker arm driven by the cam (21, 75)
(17₁, 17₂, 17₃, 17_Four) And the cam (2
Cams (2
2) The second rocker arm (18)₁, 18₂, 1
8₃, 18_Four) And the engine valve (V₂, V)
The third rocker arm (19₁, 19₂, 19₃, 19
_Four) And rocker arm shaft (24₁, 24₂) To
The third rocker arm (19₁~ 19
_Four) And the first rocker arm (17₁~ 17_Four)
And first connection switching means (30₁，
Thirty₂) And the first rocker arm (17₁~ 17_Four) And
And the third rocker arm (19₁~ 19_Four) At least one
One and the second rocker arm (18₁~ 18_Four) And
And connection release for the first connection switching means (30₁, 30 ₂) Is
Independently switchable second connection switching means (31₁, 3
1₂, 31₃) And rocker arm shaft (24₁，
24₂) Are arranged at positions displaced in the circumferential direction
And a valve operating device for an internal combustion engine. 2. The first and second connection switching means (30 ₁ ,
31 ₁ at least one of) (30 ₁₎ has a direction parallel to the axis in operable linkage piston rocker arm shaft (24 ₁₎ while being telescopically configured exerts a spring force in the extending direction (32) The connecting piston (3
2. A trigger plate (52) which can be engaged with and disengageably from (2) and can regulate the operation timing, is arranged so as to be capable of relative angular displacement with respect to the rocker arm (17 ₁ ).
A valve train for an internal combustion engine as described above. 3. The first, second and third rocker arms (1
7₂, 18₂, 19 ₂), The corresponding cam (7
5,21,22) roller followers respectively contacting
(92, 93, 94) are provided for the first and second connection
Switching means (30 ₂, 31₂) Either one (31₂)
Is arranged coaxially with the roller followers (92, 93, 94)
A valve operating valve for an internal combustion engine according to claim 1, wherein
apparatus.