JP3319883B2 - Valve train for internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve train for an internal combustion engine, and more particularly to a valve stop for closing a valve of an engine.
Relates <br/> to the valve equipment of an internal combustion engine provided on the cam shaft between a pair of cam journal portion is rotatably supported between the holder fixed to the cylinder head and the cylinder head.

[0002]

2. Description of the Related Art Conventionally, a valve gear in which a camshaft is provided with a stop portion for stopping an intake valve as an engine valve is already known, for example, from Japanese Patent Laid-Open No. 17707/1992.

[0003]

In the above-mentioned conventional apparatus, a perfect circular rest portion and a plurality of cams are provided between a pair of cam journals in a camshaft.
Spacing is provided between both cam journals, resting parts and each cam, which not only makes it difficult to shorten the camshaft in the axial direction, that is, makes the valve train compact, but also increases the number of machining steps. Also invited.

[0004]

The present invention has been made in view of the above circumstances, and in a valve gear having a camshaft provided with a stop portion for closing and stopping the engine valve, the camshaft can be shortened in the axial direction and the number of processing steps can be reduced. The purpose is to enable reduction.

[0006]

In order to achieve the above-mentioned object, the present invention is directed to a method and a method for rotating a cylinder valve between a cylinder head and a holder fixed to the cylinder head. In a valve gear for an internal combustion engine provided on a camshaft between a pair of freely supported cam journals, a rest portion adjacent to at least one of the cam journals is flush with the cam journals without leaving a gap. And it is characterized by being provided on the camshaft so as to be integrally connected .

[0007]

[0008]

In accordance with the above Ki構 formed between the cam journal portion resting portion by utilizing the cam journal portion are perfectly circular
Integrally without any gap, it is not necessary to provide a gap between the resting portion and the cam journal portion, and the cam journal portion and the resting portion can be formed simultaneously.

[0009]

[0010]

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

1 to 5 show an embodiment of the present invention. FIG. 1 is a longitudinal side view of an internal combustion engine, and FIG.
3 is a sectional view taken along line 3-3 of FIG. 2, FIG. 4 is a sectional view taken along line 4-4 of FIG. 2, and FIG.
It is a line sectional view.

First, in FIG. 1, a plurality of cylinders 11 are provided in parallel in a cylinder block 10 of this SOHC type internal combustion engine.
... are slidably fitted. The cylinder block 10
Are arranged between the pistons 12 and the combustion chambers 13.
And a pair of intake valve ports 15... And a pair of exhaust valve ports 1 are connected to the cylinder head 14 so as to open to the ceiling surface of the combustion chambers 13.
6 are provided for each cylinder 11. Both intake valve ports 15 are communicated with intake ports 17 opening on one side of the cylinder head 14, and both exhaust valve ports 16 are connected to other cylinder heads 14. Are connected to the exhaust ports 18 that open to the side surfaces. The intake manifold 19 connected to the cylinder head 14 through the intake ports 17 is provided with fuel injection valves 20 for injecting fuel toward the intake ports 17. The cylinder head 14 has an exhaust port 1
8 are connected to the exhaust manifold 21.

Corresponds to cylinder 11 that enables cylinder deactivation
, A pair that can open and close both intake valve ports 15 individually
Intake valve V as an engine valve_I, V_IIs the cylinder head
14 can be slid on guide cylinders 22.
An intake valve fitted and protruding upward from each guide cylinder 22.
V_I, V_IRetainers 23, 23 provided at the upper end of the
Each intake valve V between the cylinder head 14_I, V_ISurround
The surrounding valve springs 24 are contracted, and the valve springs 24.
By the intake valve V_I, V_IIs the direction to close the intake valve ports 15 ...
It is urged to. In addition, both exhaust valve ports 16 can be opened and closed individually.
Exhaust valve V as a pair of engine valves_E, V_EIs the cylinder
Slides on guide cylinders 25 provided on the head 14, respectively.
And project upward from each guide cylinder 25.
Exhaust valve V _E, V_ERetainer 26 provided at the upper end of the
Each exhaust valve V is provided between the cylinder head 26 and the cylinder head 14._E, V
_EAre closed and the valve springs surrounding them are contracted.
27 ... exhaust valve V_E, V_ECloses the exhaust valve ports 16 ...
Biased in the direction.

[0014] Referring also to FIGS. 2 and 3, the intake valves V _I, and V _I, interlocking with a reduction ratio of 1/2 to a crankshaft (not shown), between the cam shaft 28 which is connected the rotational movement of the intake valves V _I of the camshaft 28, the intake valve driving means 29 _I for converting the closing movement of the V _I is provided,
Both exhaust valves V _E, between the said and the V _E camshaft 28, the exhaust valves V _E rotational motion of the camshaft 28, the exhaust valve driving means 29 _E for converting the closing movement of the V _E is provided.

The camshaft 28 is connected to the cylinder head 14
And the holder 30 coupled to the cylinder head 14,
It is rotatably supported with an axis parallel to the rotation axis of the crankshaft. The cam shaft 28, the cylinder head 14 and a pair of cam journal portions 31 ₁ is rotatably supported between the holder 30, 31 ₂ are provided at intervals in the axial direction, one of the cam journal portion 31 the cam shaft 28 is at a position sequentially spaced toward from _one to the other cam journal portion 31 _2, substantially resting cam 32
When, a rest portion 33 _1, the exhaust valve actuating cam 34, and the intake valve actuating cam 35, and the rest portion 33 ₂ is integrally provided, respectively.

The intake valve operating cam 35 has an intake valve V_IOpen
It has a profile that can operate the valve,
An arc-shaped base circle portion 35 centered on the axis of the shaft 28
a and a height extending radially outward from the base circle portion 35a.
And a bottom portion 35b. In addition, the substantial pause cam 32
Valve V_IIs set to a substantial rest state, but the intake valve V _I
With a profile that can slightly open the valve.
And an arc-shaped base centered on the axis of the camshaft 28.
Radially outward from the base circular portion 32a.
And a high-order portion 32b slightly projecting from the upper portion. Further pause
Part 33₁, 33_TwoIs centered on the axis of the camshaft 28
And one of the resting portions 33
₁Is between the substantially idle cam 32 and the exhaust valve operating cam 34.
Although provided on the camshaft 28, both cam journal portions
31₁, 31_TwoResting part 33 adjacent to one of_TwoThe cam
Journal part 31_TwoThe cam jar has an outer periphery flush with
Null part 31_TwoAnd the camshaft 28
Is provided.

The actuating cam 34 for the exhaust valve is one having a profile which can exhaust valves V _E is opened and closed, an arc-shaped base circle portion 34 about the axis of the cam shaft 28
a, and a high-order portion 34b extending radially outward from the base circle portion 34a.

4 and 5, the intake valve driving means _29I includes first and second intake valve side drive rocker arms 36 and 37, and first and second intake valve side free rocker arms 38 and 37. 39 and these rocker arms 3
6 to 39 are swingably supported by an intake valve side rocker arm shaft 40 fixedly supported by the holder 30 at a position obliquely above the camshaft 28.

First and second intake valve side drive rocker arms
One end of each of 36 and 37 has an intake valve V _I, V_IAt the top of
Tapping screws 41, 41 in contact can adjust their advance / retreat position
Driven rocker arms on both intake valves
The other end portions of the camshaft 28 and the rest portion 3
3₁, 33_TwoAbutment portions 36a and 37a that abut against
It is. The second intake valve side free rocker arm 39 is on both intake valve sides.
It is arranged between the drive rocker arms 36 and 37,
The intake valve side free rocker arm 38 is connected to the first intake valve side drive rocker.
Free rocker arm on the second intake valve side with respect to the cocker arm 36
39 is arranged on the opposite side. Thus, the first intake valve side is free
The rocker arm 38 comes into rolling contact with the pause cam 32 substantially.
Roller 42 is rotatably supported, and the second intake valve side free rocker arm is supported.
A low rolling contact with the intake valve side operating cam 35
The ra 43 is pivotally supported.

The exhaust valve driving means 29 _E includes first and second exhaust valves.
Exhaust valve side drive rocker arms 44 and 45 and an exhaust valve side free rocker arm 46 are provided.
46 to 46 are holders 3 at a position obliquely above the camshaft 28.
The rocker arm shaft 47 is fixed to the exhaust valve side and is swingably supported.

The first and second exhaust valve side drive rocker arms 44 and 45 project the projection onto a plane including the axis of the camshaft 28 on the first and second intake valve side drive rocker arms 36 and 45.
37 and are arranged so as to overlap at least in part, to one end portion of both the exhaust valve-side driving rocker arms 44 and 45, the exhaust valves V _E, the tappet screws 48 and 48 abutting the upper end of the V _E The advance / retreat position is adjustable and screwed. The rest portion 33 of both the exhaust valve side to the other end portion of the driving rocker arm 44 and 45, the intake valve driving means 29 in common with the driving rocker arms 36 and 37 _I camshaft 28
_1, 33 ₂ in contact with the contact portion 44a, 45a is provided. The exhaust valve side free rocker arm 46 is disposed between the exhaust valve side drive rocker arms 44 and 45, and a roller 49 that is in rolling contact with the exhaust valve side operation cam 34 is supported on the exhaust valve side free rocker arm 46.

The holder 30 is located above each of the intake valve side rocker arms 36 to 39 and the exhaust valve side rocker arms 44 to 46.
A support plate 50 is fixed on the upper side. The support plate 50 has the first and second intake valve side free rocker arms 38 and 39 of the intake valve driving unit 29 _I and the exhaust valve driving unit 2.
Lost motion mechanism 51 to correspond to the exhaust valve side free rocker arm 46 of 9 _E ... are respectively provided.
These lost motion mechanisms 51... Incorporate a spring (not shown), and a corresponding lost motion mechanism 51 is provided above the first and second intake valve side free rocker arms 38 and 39 and the exhaust valve side free rocker arm 46.
Are provided in contact with the projections 38a, 39a, 46a. The first and second intake valve-side free rocker arms 38, 39 are resiliently moved in a direction in which the first and second intake valve-side free rocker arms 38, 39 come into contact with the substantially stationary cam 33 and the intake valve-side operation cam 35, respectively, by the spring force exerted by the lost motion mechanisms 51. The exhaust valve side free rocker arm 46 is elastically urged in the direction in which it comes into contact with the exhaust valve side operation cam 34.

In the intake valve driving means 29 _I , the first connection switching means 53 ₁ capable of switching connection and disconnection of the first and second intake rocker drive rocker arms 36 and 38 between the first and second intake rocker free rocker arms 38 and 38. is provided, switchable second connection switching means 53 ₂ is provided a coupling and uncoupling thereof 37 and 39 in the second intake valve-side driving rocker arm 37 and the second intake valve-side free rocker arm 39, the first intake The valve-side drive rocker arm 36, the second intake-valve-side drive rocker arm 37, and the second intake-valve-side free rocker arm 39 are provided with third connection switching means 54 capable of switching between connection and disconnection of these 36, 37, 39.
Also in the exhaust valve driving means 29 _E, the first exhaust valve-side driving rocker arm 44 and the exhaust valve-side free rocker arm 46
, The switchable coupling switching means 55 ₁ coupling and uncoupling thereof 44, 46 are provided, the second exhaust valve-side driving rocker arm 45 and the exhaust valve-side free rocker arm 46
, The coupling and uncoupling thereof 45 and 46 switchable connection switching means 55 ₂ is provided.

[0024] Notice in Figure 4, the first connection switching means 53 ₁ provided between the first intake valve-side driving rocker arm 36 and the first intake valve-side free rocker arm 38, sliding on the first intake valve-side free rocker arm 38 A piston 56 movably fitted, a pressing pin 57 slidably fitted to the piston 56, a spring 58 contracted between the piston 56 and the pressing pin 57, and abutting on the pressing pin 57. Switching pin 59
A regulating member 60 which is in contact with the switching pin 59 on the side opposite to the pressing pin 57 and is slidably fitted to the first intake valve side driving rocker arm 36; and the regulating member 60 and the first intake valve side driving. And a return spring 61 contracted between the rocker arms 36. The set load of the return spring 61 is set to be larger than the set load of the spring 58.

The piston 56 is formed in a bottomed cylindrical shape with one end closed, and a hydraulic chamber 62 is formed between the closed end of the piston 56 and the free rocker arm 38 on the first intake valve side. You. The first intake valve side free rocker arm 38 is provided with a communication path 63 communicating with the hydraulic chamber 62, and the communication path 63 is always communicated with an oil path 64 provided in the intake valve side rocker arm shaft 40. You.

The pressing pin 57 has an outer diameter that can be fitted into the piston 56 and is formed in a cylindrical shape with a bottom. The opening end of the pressing pin 57 faces the closed end of the piston 56 so that To be slidably fitted to. Thus the spring 58
Is contracted between the closed end of the piston 56 and the closed end of the pressing pin 57.

The switching pin 59 contacts the pressing pin 57 with a position where the switching pin 59 is straddled between the first intake valve side free rocker arm 38 and the first intake valve side drive rocker arm 36 as shown in FIG. The surface is slidable between a position fitted to the first intake valve side drive rocker arm 36 so as to correspond between the first intake valve side drive rocker arm 36 and the first intake valve side free rocker arm 38.

The regulating member 60 is formed in a bottomed cylindrical shape with one end contacting the switching pin 59 as a closed end, and the other end of the regulating member 60 has a first intake valve side drive. A collar portion 60a slidably fitted to the rocker arm 36 is provided to protrude outward in the radial direction. A stop ring 65 is fitted to the first intake valve side drive rocker arm 36 to contact the flange 60a of the regulating member 60 and regulate the movement of the regulating member 60 to one end side, that is, to the switching pin 59 side.

The axial lengths of the switching pin 59 and the regulating member 60 are such that when the regulating member 60 moves to a position where the movement is regulated by the retaining ring 65 as shown in FIG. The switching pin 59 straddles the first intake valve side drive rocker arm 36 and the first intake valve side free rocker arm 38 to connect the two rocker arms 36 and 38, but the restricting member 60 compresses the return spring 61 to compress the first spring. When the switch pin 59 is moved to a position where the switch pin 59 contacts the drive rocker arm 36, the contact surface of the switching pin 59 with the pressing pin 57 is set at a position corresponding to between the two rocker arms 36 and 38. On the other hand, the piston 56 and the pressing pin 57
As shown in FIG. 4, the switching pin 59 partially
In the state of being fitted to the intake valve side free rocker arm 38, it is slidably fitted to the first intake valve side free rocker arm 38 so as to be separated from each other by the spring force of the spring 58.

An annular engaging groove 66 is provided on the outer periphery of the piston 56. When the piston 56 and the pressing pin 57 are separated from each other as shown in FIG. An annular engagement groove 67 is formed around the pressing pin 57 between the pins 59.

[0031] The first connection switching means 53 _1,
Trigger mechanism 70 ₁ for regulating the operation timing
Is attached. The trigger mechanism 70 _1, the engagement groove 66 of the piston 56 or the piston 56 and the switching pin 59,
Between the position where the piston 56 is moved by engaging with the engaging groove 67 and the position where the movement of the piston 57 is allowed by releasing the engaged state with the engaging groove 66 or 67. A trigger plate 71 is provided that can swing relative to the two rocker arms 36 and 38 around the axis of the side rocker arm shaft 40.

A slit 72 is provided in the first free rocker arm 38 on the side of the first intake valve, and the slit 72 is engaged with the engaging groove 67 in a state where the piston 56 is maximally displaced toward the hydraulic chamber 62 as shown in FIG. The engagement groove 66 is provided on the first intake valve side free rocker arm 38 so that the piston 56 and the pressing pin 57, which are in contact with each other, maximize the volume of the hydraulic chamber 62. It is provided on the outer periphery of the piston 56 so as to be located at a position corresponding to the slit 72 in the state of being moved to the maximum.

The trigger plate 71 is rotatably supported by the rocker arm shaft 40 on the intake valve side. The trigger plate 71 is integrally provided with an engagement plate portion 71a which is detachably engaged with the engagement groove 66 or 67 from the slit 72.

A stopper pin 73 is fixed to the cylinder head 14 toward the first intake valve side free rocker arm 38. A stopper 71 b that can contact the stopper pin 73 from below is protruded from the trigger plate 71. Is done. Also, a torsion spring 7 surrounding the intake valve side rocker arm shaft 40
The other end of the torsion spring 74 is engaged with the trigger plate 71 from above by locking one end of the stopper pin 73 with the stopper pin 73.
The trigger plate 71 is urged by a torsion spring 74 in a direction in which the stopper 71b contacts the stopper pin 73. When the stopper 71b contacts the stopper pin 73, the first intake valve side free rocker arm is provided. When the stationary plate 38 is in a stationary state in contact with the base circular portion 32a of the rest cam 32, the engaging plate 71a of the trigger plate 71 is
When the first intake valve-side free rocker arm 38 swings in the valve opening direction by the high-order portion 32b of the inactive cam 32, the engagement plate portion 71a can be engaged with the engagement groove 66 or 67.
The position of the stopper pin 73 is set so that the stopper pin 73 separates from the slit 72.

According to the first connection switching means 53 ₁ and the trigger mechanism 70 ₁ , when the hydraulic pressure in the hydraulic chamber 62 is released, the switching pin 59 is shown in FIG. as in a position obtained by connecting both the rocker arms 36 and 38 straddling between the first intake valve-side driving rocker arm 36 and the first intake valve-side free rocker arm 38, this time, engagement of the trigger plate 71 in the trigger mechanism 70 ₁ The plywood portion 71a is connected to the first intake valve side free rocker arm 38.
Is depressed by the high portion 32b of the substantially inactive cam 32, it is disengaged from the engagement groove 67, and the first intake valve side free rocker arm 38 is in a stationary state in which it slides on the base circular portion 32a of the inactive cam 32. Sometimes it engages with the engagement groove 67.

Next, when hydraulic pressure is applied to the hydraulic chamber 62,
When the engagement plate portion 71a is disengaged from the engagement groove 67, the piston 56 compresses the spring 58 and moves until it contacts the switching pin 59. The switching pin 59 is moved by the first intake valve side drive rocker arm 36 and the 1 Free rocker arm 3 on intake valve side
8, the rocker arms 36 and 38 are connected to each other, and a force in the shearing direction is applied to the switching pin 59. Therefore, the piston 56 causes the switching pin 59 to move to the first intake valve side driving rocker arm 36. It is prevented from moving until it is pushed. However, when the first intake valve side free rocker arm 38 starts to slide substantially against the base circular portion 32a of the rest cam 32 and the force in the shearing direction on the switching pin 59 decreases, the piston 56 causes the switching pin 59 to move to the first position. It operates until it is pushed into the intake valve side drive rocker arm 36, whereby the connection state of the two rocker arms 36, 38 is released.

[0037] In a state where the connected state is released in this way both the rocker arms 36 and 38, the engaging plate portion 71a of the trigger plate 71 in the trigger mechanism 70 _1, the first intake valve-side free rocker arm 38 is substantially resting cam 32 When it is pushed down by the high portion 32b, it is detached from the engagement groove 66 and the first
The intake valve side free rocker arm 38 engages with the engagement groove 66 when in a stationary state in which the intake valve side free rocker arm 38 is substantially in sliding contact with the base circular portion 32 a of the rest cam 32. Thus, when the hydraulic pressure in the hydraulic chamber 62 is released and the two rocker arms 36 and 38 are connected,
The first intake valve side free rocker arm 38 is substantially
The piston 56 moves to a position where the volume of the hydraulic chamber 62 is minimized by the spring force of the spring 58 in response to the engagement plate portion 71a being detached from the engagement groove 66 by being pushed down by the high-order portion 32b of the Free rocker arm 38 on first intake valve side
Starts sliding on the base circular portion 32a of the rest cam 32, and when the axes of the pressing pin 57 and the switching pin 59 coincide with each other, the position where the switching pin 59 straddles both rocker arms 36 and 38 by the spring force of the return spring 61. And the two rocker arms 36 and 38 are connected.

A second rocker arm 37 provided between the second intake valve side drive rocker arm 37 and the second intake valve side free rocker arm 39.
The connection switching means 53 ₂ is provided with the first connection switching means 53 _1.
And are those having basically the same configuration and the trigger mechanism 70 ₂ is also a trigger mechanism 70 ₁ described above which is attached to said connection switching means 53 ₂ in order to regulate the second operation timing of the connection switching means 53 ₂ It has basically the same configuration, and has the second connection switching means 53 ₂ and the trigger mechanism 70 ₂
A detailed description of the configuration will be omitted. Thus, the second connection switching means 53 _{2
When 1} is in a disconnected state between the first intake valve side drive rocker arm 36 and the first intake valve side free rocker arm 38, the second intake valve side drive rocker arm 37 and the second
The connection between the intake valve side free rocker arms 39 is released,
First connection switching means 53 ₁ is when between the first intake valve-side driving rocker arm 36 and the first intake valve-side free rocker arm 38 and the connection mode the second intake valve-side driving rocker arm 3
So as to 7 and the second coupling between intake valve-side free rocker arm 39 state, the first connection switching means 53 ₁ in synchronization with that switching operation.

Referring to FIG. 5, the third connection switching means 54 provided on the first intake valve side drive rocker arm 36, the second intake valve side drive rocker arm 37, and the second intake valve side free rocker arm 39, Valve side drive rocker arm 36
And a switching piston 76 capable of switching between connection and disconnection of the second intake valve side free rocker arm 39 and a switching capable of switching connection and disconnection of the second intake valve side free rocker arm 39 and the second intake valve side drive rocker arm 37. A pin 77, a regulating member 78 slidably in contact with the switching pin 77 on the side opposite to the switching piston 76, and
And a return spring 79 biased to the side.

The switching piston 76 is slidably fitted to the first intake valve side drive rocker arm 36 so as to be fitted to the second intake valve side free rocker arm 39.
A hydraulic chamber 80 is formed between one end of the switching piston 76 and the first intake valve side drive rocker arm 36. A communication passage 81 communicating with the hydraulic chamber 80 is formed in the first intake valve side drive rocker arm 36, and an oil passage 82 always communicating with the communication passage 81 is provided in the intake valve side rocker arm shaft 40.
There is provided independently of the first and second connection switching means 53 _1, 53 oil passage 64 for _2. Therefore, the third connection switching means 54 includes the first and second connection switching means 53 ₁ , 5
3 ₂ and can be independently switching operation.

The switching pin 77 is slidably fitted to the second intake valve side free rocker arm 39 so that it can be fitted to the second intake valve side drive rocker arm 37. It is abutted on the edge.

The restricting member 78 is formed in a cylindrical shape with a bottom and is slidably fitted to the second intake valve side drive rocker arm 37. It is abutted on the edge. Further, a retaining ring 83 is fitted to the second intake valve side drive rocker arm 37 to abut against a flange portion 78a provided on the opening end side of the regulating member 78 to prevent the regulating member 78 from moving. The return spring 79 is contracted between the regulating member 78 and the second intake valve side drive rocker arm 37.

In the third connection switching means 54, the hydraulic chamber 8
When no oil pressure is acting on 0, as shown in FIG.
The contact surface of the switching piston 76 and the switching pin 77 is between the first intake valve side drive rocker arm 36 and the second intake valve side free rocker arm 39, and the contact surface of the switching pin 77 and the regulating member 78 is the second intake valve. Side free rocker arm 39
And the second intake valve side drive rocker arm 37, and therefore the rocker arms 36, 37, 39 are in a disconnected state. When the hydraulic pressure is applied to the hydraulic chamber 80, the switching piston 76 moves to the position where the other end is fitted to the second intake valve side free rocker arm 39, and the switching pin 7
7 moves to the position where the other end is fitted to the second intake valve side drive rocker arm 37, and the rocker arms 36, 37, 3
9 is connected.

Exhaust valve driving means 29_EIn the first exhaust
Valve side drive rocker arm 44 and exhaust valve side free rocker
Arm 46 and the second exhaust valve side drive rocker arm 45
And the exhaust valve side free rocker arm 46 respectively.
Connection switching means 55₁, 55_TwoIs the above-mentioned intake valve driving hand
Step 29_IAnd second connection switching means 53 in₁,
53_TwoHas basically the same configuration as
Switching means 55₁, 55 _TwoThe detailed description of is omitted. However
And both connection switching means 55₁, 55_TwoIs the exhaust valve side rocker
Oil pressure release of oil passage 84 provided in arm shaft 47
And the hydraulic pressure applied to the oil passage 84.
The connection status is switched synchronously between
The trigger mechanism 70 described above.₁, 70_TwoAnd basically the same
Configuration trigger mechanism 85₁, 85_TwoIs the connection switching means 55
₁, 55_TwoIt is attached to.

Next, to explain the action of this embodiment, during engine operation, the first intake valve driving means 29 _I, the second
And third connection switching means 53 _1, 53 _2, 54, and an exhaust valve driving means 29 _E connection switching means 55 _1, 55 ₂
Are all in the disconnected state, the first and second intake valve side drive rocker arms 36 and 37 and the first and second exhaust valve side drive rocker arms 44 and 45
3 ₁ lies by 33 _2, respectively hibernation the intake valves V _I, V _I and two exhaust valves V _E, V _E becomes all closed resting state, cylinder deactivation state is obtained.

Next, in the intake valve driving means 29 _I , the first and second connection switching means 53 ₁ , 53 ₂ are operated to connect while the third connection switching means 54 is in the disconnected state, and the exhaust valve driving means 29 _E In both connection switching means 55
_{When the first} and 55 ₁ are connected and operated, the first intake valve side drive rocker arm 36 is connected to the first intake valve side free rocker arm 38, and the second intake valve side drive rocker arm 37 is connected to the second intake valve side free rocker arm 39. The first and second exhaust side drive rocker arms 44 and 45 are connected to an exhaust side free rocker arm 46. Thus, whereas one of the intake valves V _I by the first intake side free rocker arm 38 is in a substantially quiescent state by substantially pause cam 32 is substantially closed rest, the second intake valve-side free rocker arm 3
9 the other intake valve V _I is opened and closed driven in characteristics corresponding to the profile of the intake valve side operating cam 35 by being driven to the intake valve side operating cam 35, both the exhaust valves V _E,
V _E is driven to open and close with characteristics both depending on the profile of the exhaust-side operating cam 34. Therefore, one intake valve V _I
There can improve combustibility as possible to generate a swirl in the combustion chamber 13 in response to the state in a substantially resting state and the other intake valve V _I is opened and closed, a low speed of the engine A large amount of exhaust gas circulation and lean combustion can be performed in the region, so that fuel efficiency can be reduced and drivability can be improved.

Further, in the intake valve driving means 29 _I , the third
The connection switching means 54 is operated for connection, and the exhaust valve driving means 2 is operated.
_{9E, when} the two connection switching means 55 ₁ , 55 ₁ are held in the connected state, the first and second intake valve side drive rocker arms 3
6, 37 are connected to the second free rocker arm 39 on the intake valve side, and the first and second exhaust side drive rocker arms 44, 45.
Remain connected to the exhaust-side free rocker arm 46. Therefore, the second intake valve-side free rocker arm 39 is driven to be opened and closed with characteristics corresponding to the profile of the intake valves V _I, V _I are both intake valve side operating cam 35 by being driven to the intake valve side operating cam 35 both exhaust valves V _E, V _E will be both driven to open and close with characteristics corresponding to the profile of the exhaust-side operating cam 34.

[0048] In such a valve operating system, one 33 ₂ of the pair of rest portions 33 _1, 33 ₂ provided on the camshaft 28, so provided integrally with the outer peripheral surface as flush to the cam journal portion 31 ₂ , Cam journal part 31 ₂
Compared to the conventional one at a position spaced axially resting portion 33 ₂ provided from enables axial shortening of the camshaft 28, a further pause portion 33 ₂ and the cam journal portion 31 ₂ since at the same time it can be molded, as compared resting portion 33 ₂ and the cam journal portion 31 ₂ and the conventional one had to be molded, respectively, reduce the number of processing steps.

Moreover, the drive rocker arm 36 on the first intake valve side of the intake valve drive means 29 _I and the exhaust valve drive means 29 _E
Of the first exhaust valve-side drive rocker arm 44
3 ₁ , the second intake valve side drive rocker arm 37 of the intake valve drive means 29 _I and the second exhaust valve side drive rocker arm 45 of the exhaust valve drive means are connected to the other rest part 33.
₂ , the two stop portions 33, which are the minimum necessary compared to the case where the drive rocker arms 36, 37, 44, and 45 are provided with the stop portions individually.
_1, 33 ₂ are so only to be provided on the camshaft 28, it is possible to achieve further axial shortening of the camshaft 28, it is possible to reduce the number of processing steps due to a decrease in resting portion molding number.

Since the camshaft 28 can be shortened in the axial direction as described above, the valve train can be made more compact. In addition, the width of the substantially idle cam 32 and each of the operating cams 34, 35 is increased by the shortening in the axial direction, and the contact area between each of the cams 32, 34, 35 and the rollers 42, 43, 49 is increased, thereby improving durability and wear resistance. It is also possible to improve the performance.

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 present invention can be applied to a valve train in which only one of a pair of intake valves and one of a pair of exhaust valves are closed and stopped at a perfect circular stop. Further, the number of rocker arms is not limited to that of the above embodiment.

[0053]

As described above, according to the present invention, a perfect circular stop portion for closing and stopping the engine valve is provided between the cylinder head and the holder fixed to the cylinder head so as to be rotatably supported. in a valve operating system for an internal combustion engine provided on the cam shaft between the cam journal portion, resting portion adjacent to at least one of the cam journal portion is continuous with flush and integrally without leaving a gap the cam journal portion mosquito Since it is provided on the camshaft, there is no need to provide a gap between the rest portion and the cam journal portion, so that the camshaft can be shortened in the axial direction and the valve gear can be made compact, and the camshaft can be further reduced. The number of processing steps can be reduced by simultaneously forming the journal portion and the pause portion.

[0054]

[Brief description of the drawings]

FIG. 1 is a vertical side view of an internal combustion engine.

FIG. 2 is a view taken along line 2-2 of FIG. 1;

FIG. 3 is a sectional view taken along line 3-3 in FIG. 2;

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

FIG. 5 is a sectional view taken along line 5-5 in FIG. 2;

[Explanation of symbols]

14 ... Cylinder head 28 ... Cam shaft 30 ... Holder 31 ₁ , 31 ₂ ... Cam journal section 33 ₁ , 33 ₂ ... Pause section V _E ... Exhaust valve as engine valve V _I・ ・ ・ Intake valve as engine valve

──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Hiroyuki Niikura 1-4-1 Chuo, Wako-shi, Saitama Inside Honda R & D Co., Ltd. (56) References JP-A-4-17707 (JP, A) JP-A Sho 61-166980 (JP, A) Japanese Utility Model Showa 61-57110 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) F01L 13/00 302 F01L 13/00 303 F01L 1/04

Claims (1)

(57) [Claims] 1. A circular rest portion (33 ₁ , 33 ₂ ) for closing and stopping the engine valve (V _I , V _E ) is fixed to the cylinder head (14) and the cylinder head (14). A camshaft ( ₂ ) is inserted between a pair of cam journals (31 ₁ , 31 ₂ ) rotatably supported between holders (30).
In a valve operating system for an internal combustion engine provided in 8), resting portion adjacent to at least one of the cam journal portion (31 ₂₎ (33 _2), the gap to the cam journal portion (31 ₂₎
Without opening the camshaft (2
8) A valve gear for an internal combustion engine, which is provided in 8).
Place.