JPH0874539A - Valve system of internal combustion engine - Google Patents

Abstract

PURPOSE: To shorten a cam shaft in the axial direction, and to reduce processing man-hours by providing rest part adjacent to at least one side cam journal part on a cam shaft so that it may be flush with and integral with the cam journal part. CONSTITUTION: Rest parts 331 , 332 are formed into a round shape taking an axis of a cam shaft 28 as the center. The rest part 331 is provided on the cam shaft 28 between a substantial rest cam 32 and an exhaust valve operating cam 34, and the rest part 332 adjacent to a cam journal part 312 is provided with the outer periphery flush with the cam journal part 312 and provided on the cam shaft 28 so as to be integrated with the journal part 312 . Thereby, the cam shaft can be axially shortened in comparison with the conventional one wherein the rest part 332 is provided in the position axially distant from the cam journal part 312 , and the rest part 332 and the cam journal part 312 can be simultaneously formed, and decrease of processing man-hours can be achieved.

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, and more particularly, to a perfect circular resting part for closing and resting an engine valve.
A valve operating device for an internal combustion engine provided on a cam shaft between a pair of cam journal portions rotatably supported between a cylinder head and a holder fixed to the cylinder head,
In addition, the camshaft is provided with a perfect circle-shaped pause portion for closing and closing the intake valve and the exhaust valve, and the exhaust valve side drive that is linked and linked to the rocker arm and the exhaust valve is linked and linked to the intake valve. A rocker arm relates to a valve operating device of an internal combustion engine, which is brought into contact with a rest portion.

[0002]

2. Description of the Related Art Heretofore, a valve operating device in which a cam shaft is provided with a pause portion for stopping an intake valve as an engine valve is already known, for example, from Japanese Patent Application Laid-Open No. 4-17707.

[0003]

By the way, in the above-mentioned prior art, a perfect circular rest portion and a plurality of cams are provided between a pair of cam journals on the camshaft,
Since there is a space between each cam journal, the rest part, and each cam, it is difficult to shorten the cam shaft in the axial direction, that is, to make the valve gear compact, and increase the number of machining steps. Is also invited.

Further, in a SOHC type valve operating device having a single camshaft which is common to both the intake valve and the exhaust valve, it is necessary not only to suspend the intake valve but also the exhaust valve when the cylinder is deactivated. Yes, in this case, it is simply necessary to separately provide a rest portion for the intake valve and a rest portion for the exhaust valve on the camshaft, but this makes it difficult to shorten the camshaft in the axial direction and increases the number of processing steps. Will be done.

The present invention has been made in view of the above circumstances, and in a valve operating system in which a cam shaft is provided with a pausing portion for closing and pausing the engine valve, the axial direction of the cam shaft is shortened and the number of machining steps is reduced. The purpose is to enable reduction.

[0006]

In order to achieve the above object, the invention according to claim 1 is such that a perfect circular rest portion for stopping and closing the engine valve is fixed to the cylinder head and the cylinder head. In a valve operating system for an internal combustion engine provided on a cam shaft between a pair of cam journal portions rotatably supported between holders, at least a rest portion adjacent to one cam journal portion is flush with the cam journal portion. It is characterized in that it is integrally provided on the camshaft.

According to a second aspect of the present invention, the camshaft is provided with a perfect circular resting portion for closing and closing the intake valve and the exhaust valve, and the intake valve side drive rocker arm and the exhaust which are linked and connected to the intake valve. In a valve operating system of an internal combustion engine in which an exhaust valve-side drive rocker arm that is interlocked with and connected to a valve is in contact with a rest portion, at least partially overlap projections onto a plane including an axis of a camshaft. The intake valve-side drive rocker arm and the exhaust valve-side drive rocker arm that are arranged are brought into contact with a common rest portion.

[0008]

According to the structure of the invention described in claim 1, the pausing portion and the cam journal are integrated so as to be flush with the cam journal portion by utilizing the fact that the cam journal portion has a perfect circle shape. It is not necessary to provide a gap between the parts, and the cam journal part and the rest part can be molded at the same time.

According to the second aspect of the present invention, the intake valve side drive rocker arm and the exhaust valve skin drive rocker arm are brought into contact with a common rest portion to minimize the number of rest portions. You can

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 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 vertical sectional side view of an internal combustion engine, and FIG. 2 is FIG.
2-2 line arrow view, 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, and a piston 12 is provided in each cylinder 11.
... are slidably fitted. In addition, the cylinder block 10
On the upper surface of the combustion chamber 13 ...
Is coupled to the cylinder head 14, and a pair of intake valve openings 15 ... And a pair of exhaust valve openings 1 are formed in the cylinder head 14 so as to open on the ceiling surface of the combustion chamber 13.
6 are provided for each cylinder 11, and both intake valve ports 15 are communicated with an intake port 17 that opens on one side surface of the cylinder head 14, and both exhaust valve ports 16 are other than the cylinder head 14. It communicates with the exhaust ports 18 ... Opening to the side surface. 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
The exhaust manifold 21 leading to 8 ... Is connected.

Corresponding to the cylinder 11 that enables cylinder deactivation
A part that can open and close both intake valve ports 15 ... individually
Intake valve V as an engine valve of_I, V_IThe cylinder head
Slidable on the guide cylinders 22 ...
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 is connected to the cylinder head 14._I, V_IEnclose
The coiled valve springs 24 ... Are contracted, and the valve springs 24 ...
By intake valve V_I, V_IIs the direction to close the intake valve port 15 ...
Be urged by. 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
Sliding on the guide cylinders 25 provided on the head 14, respectively.
It fits as much as possible and protrudes upward from each guide tube 25 ...
Exhaust valve V _E, V_EA retainer 26 provided at the upper end of the
26 and the cylinder head 14 between the exhaust valves V_E, V
_EThe valve springs 27 that surround the
27 ... Exhaust valve V_E, V_ECloses the exhaust valve opening 16 ...
Is urged in the direction of.

Referring to FIGS. 2 and 3 together, between the intake valves V _I and V _I and a cam shaft 28 which is interlocked and connected to a crank shaft (not shown) at a speed reduction ratio of 1/2. Is provided with intake valve drive means 29 _I for converting the rotational movement of the camshaft 28 into the opening / closing movement of the intake valves V _I , V _I ,
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 cam shaft 28 is used for the cylinder head 14.
And a holder 30 connected to the cylinder head 14,
It is rotatably supported with an axis parallel to the axis of rotation of the crankshaft. The camshaft 28 is provided with a pair of cam journal portions 31 ₁ and 31 _{2 which} are rotatably supported between the cylinder head 14 and the holder 30 at intervals in the axial direction. _The camshaft 28 has a substantially stationary cam 32 at a position sequentially spaced from ₁ to the other cam journal 31 _2.
The pause portion 33 ₁ , the exhaust valve actuation cam 34, the intake valve actuation cam 35, and the pause portion 33 ₂ are integrally provided.

The intake valve actuating cam 35 includes an intake valve V_IOpen
It has a profile that allows valve actuation.
An arc-shaped base circle portion 35 centered on the axis of the shaft 28
a and the height of the base circular portion 35a protruding outward in the radial direction.
And a position portion 35b. In addition, the actual stop cam 32
Valve V_IOf the intake valve V at the opening timing. _I
With a profile that allows the valve to be opened slightly
The arc-shaped base around the axis of the camshaft 28.
Radius 32a and radially outward from the base circle 32a
It has a high part 32b that slightly overhangs. Further pause
Part 33₁, 33₂Around the axis of the camshaft 28
Is formed in a perfect circular shape, and the one rest portion 33
₁Is substantially between the rest cam 32 and the exhaust valve actuating cam 34.
Both cam journal parts are provided on the camshaft 28.
31₁, 31₂The rest portion 33 adjacent to one side₂The cam
Journal section 31₂The cam jar having a flush outer periphery with
Null part 31₂Camshaft 28 so as to be integrated with
It is provided in.

The exhaust valve actuating cam 34 has a profile capable of opening and closing the exhaust valve V _E , and has an arcuate base circle 34 centered on the axis of the camshaft 28.
a and a high portion 34b protruding radially outward from the base circular portion 34a.

Referring to FIGS. 4 and 5 together, the intake valve drive means 29 _I 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 a holder 30 at a position obliquely above the cam shaft 28.

First and second intake valve side drive rocker arms
At one end of each of 36 and 37, an intake valve V _I, V_IHit the top of
The advancing / retreating position can be adjusted by the tappet screws 41, 41 touching
It is screwed as a function, and both intake valve side drive rocker arm
At the other end of 36 and 37, the rest portion 3 of the camshaft 28 is provided.
Three₁, 33₂Contact portions 36a, 37a for contacting the
Be done. 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, and the first
The intake valve side free rocker arm 38 includes a first intake valve side drive lock arm.
Second intake valve side free rocker arm with respect to the armature arm 36
It is arranged on the side opposite to 39. Thus, the first intake valve side is free
The rocker arm 38 is substantially in rolling contact with the rest cam 32.
Roller 42 is pivotally supported and the second intake valve side free rocker
The cam 39 is in low contact with the intake valve side actuating cam 35.
La 43 is pivotally supported.

The exhaust valve driving means 29 _E includes the first and second exhaust valves.
Exhaust valve side drive rocker arms 44 and 45 and exhaust valve side free rocker arm 46 are provided.
~ 46 is the holder 3 at a position obliquely above the camshaft 28.
It is rockably supported by an exhaust valve side rocker arm shaft 47 which is fixedly supported at 0.

The first and second exhaust valve side drive rocker arms 44, 45 project the projection onto the plane including the axis of the camshaft 28 into the first and second intake valve side drive rocker arms 36, 45.
37, at least partially overlapping the exhaust valve side drive rocker arms 44, 45 with tappet screws 48, 48 abutting the upper ends of the exhaust valves V _E , V _E. The advancing / retreating position is adjustable and screwed. At the other end of both the exhaust valve side drive rocker arms 44 and 45, the rest portion 33 of the camshaft 28 is shared by the both drive rocker arms 36 and 37 of the intake valve drive means 29 _I.
Abutting portions 44a and 45a that come into contact with ₁ , 33 ₂ are provided. The exhaust valve side free rocker arm 46 is arranged between the exhaust valve side drive rocker arms 44 and 45, and a roller 49 which is in rolling contact with the exhaust valve side actuating cam 34 is pivotally supported on the exhaust valve side free rocker arm 46.

The holder 30 is provided above 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 support plate 50, on which the first and second intake valve side free rocker arms 38 and 39 of the intake valve drive means 29 _I and the exhaust valve drive means 2 are mounted.
Lost motion mechanisms 51 ... Are provided corresponding to the exhaust valve side free rocker arms 46 of 9 _E , respectively.
These lost motion mechanisms 51 ... Incorporate a spring (not shown), and the corresponding lost motion mechanisms 51 are provided above the first and second intake valve-side free rocker arms 38 and 39 and the exhaust valve-side free rocker arm 46.
Abutting protrusions 38a, 39a, 46a that come into contact with. Thus, the spring force exerted by each lost motion mechanism 51 causes the first and second intake valve-side free rocker arms 38, 39 to elastically move in the directions in which they come into contact with the substantially rest cam 33 and the intake valve-side actuating cam 35, respectively. The free rocker arm 46 on the exhaust valve side is elastically biased in the direction of coming into contact with the operation cam 34 on the exhaust valve side.

In the intake valve drive means 29 _I , the first intake valve side drive rocker arm 36 and the first intake valve side free rocker arm 38 can be connected and disconnected by the first connection switching means 53 ₁ The second intake valve-side drive rocker arm 37 and the second intake valve-side free rocker arm 39 are provided with second connection switching means 53 ₂ capable of switching connection and disconnection of these 37, 39. 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 a third connection switching means 54 capable of switching connection and disconnection of these 36, 37, 39.
Further, in the exhaust valve drive means 29 _E , the first exhaust valve side drive rocker arm 44 and the exhaust valve side free rocker arm 46.
Is provided with connection switching means 55 ₁ capable of switching connection and disconnection of these 44, 46, and the second exhaust valve side drive rocker arm 45 and the exhaust valve side free rocker arm 46.
Is provided with a connection switching means 55 ₂ capable of switching connection and disconnection of these 45 and 46.

Referring to FIG. 4, the first connection switching means 53 ₁ provided between the first intake valve side drive rocker arm 36 and the first intake valve side free rocker arm 38 slides on the first intake valve side free rocker arm 38. A piston 56 that is movably fitted, a pressing pin 57 that is slidably fitted to the piston 56, a spring 58 that is compressed between the piston 56 and the pressing pin 57, and abuts on the pressing pin 57. Switching pin 59
And a regulating member 60 that is in contact with the switching pin 59 on the opposite side of the pressing pin 57 and is slidably fitted to the first intake valve side drive rocker arm 36, and the regulating member 60 and the first intake valve side drive. A return spring 61 that is contracted between the rocker arms 36 is provided, and 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 first intake valve side free rocker arm 38. It Further, the first intake valve-side free rocker arm 38 is provided with a communication passage 63 communicating with the hydraulic chamber 62, and the communication passage 63 is always communicated with an oil passage 64 provided in the intake valve-side rocker arm shaft 40. It

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

As shown in FIG. 4, the switching pin 59 abuts the position where the first intake valve side free rocker arm 38 and the first intake valve side drive rocker arm 36 are fitted over the pressing pin 57. The surface is made slidable between the first intake valve side drive rocker arm 36 and the first intake valve side free rocker arm 38 and the position fitted to the first intake valve side drive rocker arm 36.

The regulating member 60 is formed in a bottomed cylindrical shape with one end contacting the switching pin 59 being a closed end, and the other end of the regulating member 60 is driven by the first intake valve. A brim portion 60a slidably fitted to the rocker arm 36 is provided so as to project outward in the radial direction. Further, a retaining ring 65 is fitted to the first intake valve side drive rocker arm 36 to abut the flange portion 60a of the regulating member 60 and regulate the movement of the regulating member 60 to one end side, that is, the switching pin 59 side.

The axial lengths of the switching pin 59 and the regulating member 60 come into contact with the regulating member 60 when the regulating member 60 moves to a position where movement is restricted 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, 38, but the restricting member 60 compresses the return spring 61 to make the first When it moves to a position where it abuts on the intake valve side drive rocker arm 36, the contact surface of the switching pin 59 with the pressing pin 57 is set to a position corresponding to between the 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
When fitted to the intake valve side free rocker arm 38, they are 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.

By the way, an annular engaging groove 66 is provided on the outer periphery of the piston 56, and when the piston 56 and the pressing pin 57 are in a state of being separated from each other as shown in FIG. An annular engagement groove 67 is formed around the pressing pin 57 between the pins 59.

The first connection switching means 53 ₁ as described above includes
Trigger mechanism 70 ₁ for regulating its 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 positions where the piston 56 is engaged with the engaging groove 67 to restrict the movement of the piston 56, and the positions where the engagement with the engaging groove 66 or 67 is released to allow the piston 57 to move. The side rocker arm shaft 40 is provided with a trigger plate 71 capable of swinging relative to both rocker arms 36 and 38 around the axis.

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

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

A stopper pin 73 is fixedly provided on the cylinder head 14 toward the first intake valve side free rocker arm 38 side, and a stopper 71b capable of contacting the stopper pin 73 from below is provided to project from the trigger plate 71. To be done. In addition, the torsion spring 7 surrounding the intake valve side rocker arm shaft 40
One end of 4 is locked to the stopper pin 73, and the other end of the torsion spring 74 is locked to the trigger plate 71 from above.
Thus, the trigger plate 71 is biased by the torsion spring 74 in the direction of bringing the stopper 71b into contact with the stopper pin 73, and with the stopper 71b in contact with the stopper pin 73, the first intake valve side free rocker arm. When 38 is in a stationary state by abutting on the base circular portion 32a of the substantially resting cam 32, the engaging plate portion 71a of the trigger plate 71 is provided with the slit 72.
Can be engaged with the engaging groove 66 or 67 from the engaging groove portion 66 or 67, and when the first intake valve side free rocker arm 38 swings in the valve opening direction by the high portion 32b of the substantially rest cam 32, the engaging plate portion 71a.
The position of the stopper pin 73 is set so that is separated from the slit 72.

According to the first connection switching means 53 ₁ and the trigger mechanism 70 ₁ as described above, the switching pin 59 is shown in FIG. 4 by the spring force of the return spring 61 when the hydraulic pressure in the hydraulic chamber 62 is released. As described above, the rocker arms 36 and 38 are connected to each other by straddling the first intake valve side drive rocker arm 36 and the first intake valve side free rocker arm 38. At this time, the engagement of the trigger plate 71 in the trigger mechanism 70 ₁ is performed. The plywood portion 71a includes the first intake valve side free rocker arm 38.
Is pushed down by the high position portion 32b of the substantially resting 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 sliding contact with the base circle portion 32a of the substantially resting cam 32. Sometimes it engages with the engagement groove 67.

Next, when hydraulic pressure is applied to the hydraulic chamber 62,
The piston 56 moves until it comes into contact with the switching pin 59 by compressing the spring 58 when the engaging plate portion 71a is disengaged from the engaging groove 67. The switching pin 59 causes the first intake valve side drive rocker arm 36 and the 1 Intake valve side free rocker arm 3
Since the rocker arms 36 and 38 are connected to each other across 8 and the force in the shearing direction acts on the switching pin 59, 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 in. However, when the first intake valve side free rocker arm 38 starts sliding contact with the base circular portion 32a of the substantially rest cam 32 and the force in the shearing direction on the switching pin 59 becomes small, the piston 56 moves the switching pin 59 to the first position. It operates until it is pushed into the intake valve side drive rocker arm 36, whereby the connected state of both rocker arms 36, 38 is released.

In the state where the two rocker arms 36 and 38 are disconnected from each other in this way, the engagement plate portion 71a of the trigger plate 71 in the trigger mechanism 70 ₁ is arranged such that the first intake valve side free rocker arm 38 is substantially the rest cam 32. When it is pushed down by the high position portion 32b, it is disengaged from the engaging groove 66,
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 circle portion 32 a of the rest cam 32. Thus, when the hydraulic pressure in the hydraulic chamber 62 is released to bring both rocker arms 36, 38 into the connected state,
The first intake valve side free rocker arm 38 is substantially stopped by the cam 32.
The piston 56 moves to the 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 disengaged from the engagement groove 66 by being pushed down by the high-order portion 32b. First intake valve side free rocker arm 38
Is a position where the switching pin 59 straddles both rocker arms 36 and 38 due to the spring force of the return spring 61 when the sliding contact with the base circular portion 32a of the stationary cam 32 begins and the axes of the pressing pin 57 and the switching pin 59 coincide. The rocker arms 36 and 38 are connected to each other.

The second intake valve side drive rocker arm 37 and the second intake valve side free rocker arm 39 provided between the second
The connection switching means 53 ₂ is the above-mentioned first connection switching means 53 ₁
And the trigger mechanism 70 ₂ attached to the connection switching means 53 ₂ in order to regulate the operation timing of the second connection switching means 53 ₂ as well as the above-mentioned trigger mechanism 70 ₁ . The second connection switching means 53 ₂ and the trigger mechanism 70 ₂ have basically the same configuration.
The detailed description of the configuration will be omitted. Thus, the second connection switching means 53 ₂ is the first connection switching means 53.
_{When 1} disengages the first intake valve side drive rocker arm 36 and the first intake valve side free rocker arm 38 from each other, the second intake valve side drive rocker arm 37 and the second intake valve side drive rocker arm 37
The connection between the free rocker arms 39 on the intake valve side 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
7 and the second intake valve side free rocker arm 39 are connected to each other to perform a switching operation in synchronization with the first connection switching means 53 ₁ .

Focusing on 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 is the first intake air intake side. Valve side drive rocker arm 36
And a switching piston 76 capable of switching connection and disconnection of the second intake valve side free rocker arm 39, and 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. The pin 77 and a regulating member 78 that is in sliding contact with the switching pin 77 on the side opposite to the switching piston 76, and the regulating member 78 is the switching pin 77.
And a return spring 79 for biasing the side.

The switching piston 76 is adapted to be fitted to the second intake valve side free rocker arm 39 and slidably fitted to the first intake valve side drive rocker arm 36.
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 constantly communicating with the communication passage 81 is provided in the intake valve side rocker arm shaft 40.
However, it is provided independently of the oil passage 64 for the first and second connection switching means 53 ₁ and 53 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 driving rocker arm 37, and one end of this switching pin 77 is the other of the switching piston 76. Abutted on the edge.

The regulating 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. The closed end of the regulating member 78 is the other of the switching pin 77. Abutted on the edge. Further, a retaining ring 83 is fitted to the second intake valve side drive rocker arm 37 for abutting against a flange portion 78 a 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 restriction member 78 and the second intake valve side drive rocker arm 37.

In the third connection switching means 54, the hydraulic chamber 8
When hydraulic pressure is not acting on 0, as shown in FIG.
The contact surfaces of the switching piston 76 and the switching pin 77 are between the first intake valve side drive rocker arm 36 and the second intake valve side free rocker arm 39, and the contact surfaces of the switching pin 77 and the restriction member 78 are the second intake valve. Side free rocker arm 39
And between the second intake valve side driving rocker arm 37, and therefore the rocker arms 36, 37, 39 are in the disconnected state. When hydraulic pressure is applied to the hydraulic chamber 80, the switching piston 76 moves its other end side to a position where it is fitted into the second intake valve side free rocker arm 39, and the switching pin 7
7 moves the other end side to the position where it is fitted to the second intake valve side drive rocker arm 37, and the rocker arms 36, 37, 3
9 is in a connected state.

Exhaust valve drive means 29_EAt the first exhaust
Valve side drive rocker arm 44 and exhaust valve side free rocker arm
Arm 46 and second exhaust valve side drive rocker arm 45
And the free rocker arm 46 on the exhaust valve side.
Connection switching means 55₁, 55₂Is the intake valve drive hand
Step 29_IFirst and second connection switching means 53 in₁,
53₂It has basically the same configuration as
Switching means 55₁, 55 ₂The detailed description of is omitted. However
Both connection switching means 55₁, 55₂Is the exhaust valve side rocker
Hydraulic release of oil passage 84 provided in arm shaft 47
When the hydraulic pressure is applied to the oil passage 84,
It is configured to switch between the connection release state and the connection release state in synchronization.
And the trigger mechanism 70 described above.₁, 70₂Basically the same as
Configuration trigger mechanism 85₁, 85₂Is each connection switching means 55
₁, 55₂Attached to.

Next, the operation of this embodiment will be described. When the engine is operating, the first and second intake valve driving means 29 _I are operated.
And third connection switching means 53 ₁ , 53 ₂ , 54 and connection switching means 55 ₁ , 55 _{2 of the} exhaust valve driving means 29 _E.
When all of them are in the decoupled 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 have the rest portion 3
3 ₁ and 33 ₂ are in a deactivated state, and both intake valves V _I and V _I and both exhaust valves V _E and V _E are all closed and a cylinder deactivated state is obtained.

Next, in the intake valve driving means 29 _I , the first and second connection switching means 53 ₁ and 53 ₂ are connected and operated while the third connection switching means 54 is in the connection released state, and the exhaust valve driving means 29 _E. In both connection switching means 55
_{When 1} 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 the exhaust side free rocker arm 46. Therefore, since the first intake side free rocker arm 38 is in the substantially resting state by the substantially resting cam 32, one of the intake valves V _I is substantially closed and rested, whereas the second intake valve side free rocker arm 38 is substantially rested. Three
9 is driven by the intake valve side actuating cam 35, the other intake valve V _I is opened and closed with a characteristic according to the profile of the intake valve side actuating cam 35, and both exhaust valves V _E ,
Both V _E are opened / closed with a characteristic according to the profile of the exhaust side operation cam 34. Therefore, one intake valve V _I
Can be generated in the combustion chamber 13 in response to the opening / closing operation of the other intake valve V _{I in} a state in which the engine is in a substantially idle state to improve the combustibility and reduce the engine speed. A large amount of exhaust gas circulation and lean combustion can be executed in the region, which can reduce fuel consumption and improve drivability.

Further, in the intake valve drive means 29 _I ,
The connection switching means 54 is operated for connection, and the exhaust valve driving means 2
When the 9 _E both 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 intake valve side free rocker arm 39, and are connected to the first and second exhaust side drive rocker arms 44, 45.
Remains connected to the exhaust side free rocker arm 46. Therefore, the second intake valve-side free rocker arm 39 is driven by the intake valve-side actuating cam 35, so that both intake valves V _I and V _I are both opened and closed with characteristics according to the profile of the intake valve-side actuated cam 35. , Both the exhaust valves V _E and V _E are driven to open and close with the characteristics according to the profile of the exhaust side operation 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 Department 31 ₂
Compared to the conventional one in which the pause portion 33 ₂ is provided at a position spaced apart in the axial direction from the above, the camshaft 28 can be shortened in the axial direction, and the pause portion 33 ₂ and the cam journal portion 31 ₂ can be further shortened. Since they can be molded at the same time, the number of processing steps can be reduced as compared with the conventional one in which the rest portion 33 ₂ and the cam journal portion 31 ₂ are respectively molded.

Moreover, the first intake valve side drive rocker arm 36 of the intake valve drive means 29 _I and the exhaust valve drive means 29 _E
The first exhaust valve side drive rocker arm 44 of FIG.
3 ₁ is in contact with the common intake valve driving means 29 the second exhaust valve-side driving rocker arm 45 and the other resting portion 33 of the second intake valve-side driving rocker arm 37 and the exhaust valve driving means _{I
The two} rest portions 33, which are the minimum required, are compared with those in which a rest portion is provided corresponding to each of the drive rocker arms 36, 37, 44, 45 by being abutted against the _two in common.
_{Since 1} , 33 ₂ need only be provided on the camshaft 28, the axial length of the camshaft 28 can be further shortened, and the man-hours required for processing can be reduced by reducing the number of moldings of the rest portion.

Since the camshaft 28 can be shortened in the axial direction in this manner, the valve train can be made compact. Further, the width of the substantially resting cam 32 and the respective actuating cams 34, 35 is expanded by the shortened portion in the axial direction to increase the contact area between the respective cams 32, 34, 35 and the rollers 42, 43, 49, thereby improving durability and wear resistance. It is also possible to improve the property.

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 in which only one of the pair of intake valves and one of the pair of exhaust valves are closed by the perfect circular rest portion. Further, the number of rocker arms is not limited to that in the above embodiment.

[0053]

As described above, according to the first aspect of the present invention, the perfect circular rest portion for closing and resting the engine valve is rotatable between the cylinder head and the holder fixed to the cylinder head. In a valve operating system for an internal combustion engine provided on a cam shaft between a pair of supported cam journal parts, a rest part adjacent to at least one cam journal part is flush with and integrated with the cam journal part on the cam shaft. Since it is provided, it is not necessary to provide a gap between the rest portion and the cam journal portion, the axial direction of the cam shaft can be shortened, and the valve train can be made compact, and the cam journal portion and the rest portion can be provided. The number of processing steps can be reduced by simultaneously molding.

According to the second aspect of the invention, the intake valve side drive rocker arm is provided on the camshaft with a perfect circular resting portion for closing and closing the intake valve and the exhaust valve. And an exhaust valve-side drive rocker arm that is linked to and connected to the exhaust valve at least partially overlap the projection on the plane including the axis of the camshaft in the valve train of the internal combustion engine that is in contact with the rest portion. Since the intake valve-side drive rocker arm and the exhaust valve-side drive rocker arm that are arranged so as to contact each other are in contact with a common rest portion, the number of rest portions is minimized to shorten the axial direction of the camshaft and thus to move. The valve device can be made compact and the number of processing steps can be reduced.

[Brief description of drawings]

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

FIG. 2 is a view taken along the line 2-2 of FIG.

3 is a sectional view taken along line 3-3 of FIG.

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

5 is a sectional view taken along line 5-5 of FIG.

[Explanation of Codes] 14 ... Cylinder Head 28 ... Cam Shaft 30 ... Holders 31 ₁ , 31 ₂ ... Cam Journal Section 32 ... Substantially Resting Cams 33 ₁ , 33 ₂ ... Resting Section 35 ... operating cam 36, 37 ... intake valve-side driving rocker arms 44, 45 ... exhaust valve-side driving rocker arm V _E ... exhaust valves V _I ... intake valve

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiroyuki Niikura 1-4-1 Chuo, Wako-shi, Saitama Stock Engineering Company Honda R & D Co., Ltd.

Claims (2)

[Claims] 1. A engine valve (V _I, V _E) circular shape resting portion for closing pause (33 _1, 33 ₂₎ is fixed to the cylinder head (14) and said cylinder head (14) The cam shaft (2) is provided between the pair of cam journal portions (31 ₁ , 31 ₂ ) rotatably supported between the holders (30).
In the valve operating system for an internal combustion engine provided in 8), at least one cam journal portion (31 ₂ ) has a rest portion (33 ₂ ) adjacent to the cam journal portion (31 ₂ ) which is flush with and integrated with the cam journal portion (31 ₂ ). A valve train for an internal combustion engine, which is provided on a shaft (28). 2. An intake valve (V_I) And an exhaust valve (V_E)
A perfect circle-shaped pause part (33 for closing the valve)₁, 33₂) Is
The intake valve (V _I) To
Intake valve side driven rocker arm (36, 3
7) and exhaust valve (V _E) Linked to and connected to the exhaust valve side
The rocker arms (44, 45) and the rest portion (33₁, 3
Three₂) In the valve train of the internal combustion engine
The projection on the plane including the axis of the camshaft (28).
Intake valve side drive arranged at least partially overlapping
Rocker arm (36, 37) and exhaust valve side drive rocker
The arms (44, 45) have a common rest (33₁, 33
₂), The valve device for an internal combustion engine
Place.