JPH0544418A - Variable valve timing and lift mechanism - Google Patents

Abstract

PURPOSE:To speed up changing-over speed of valve opening and closing timing or valve lift of inlet and exhaust valves, and also to reduce abnormal noise generation in the case of changing-over of an internal combustion engine from a low speed to a high speed. CONSTITUTION:There are provided a low speed rocker arm 3 which makes an inlet valve open and close by making them rock by means of a low speed cam having a small working angle or lift, and a high speed rocker arm 4 which is rocked by means of a high speed cam having a large working angle or lift. Furthermore, there are provided a hydraulic piston 52 by which the high speed rocker arm 4 is separated from the low speed rocker arm 3 in the case of low speed running of an internal combustion engine, and the high speed rocker arm 4 is connected to the low speed rocker arm 3 in the case of high speed running of the internal combustion engine. And, a notch 58 is formed on a hydraulic pressure acting surface 57 for supplying working fluid 7 to the hydraulic pressure acting surface 57.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mechanism for switching the opening / closing timing of an intake / exhaust valve or the lift amount between low speed and high speed of an internal combustion engine, and more particularly to speeding up the switching speed.

[0002]

2. Description of the Related Art A conventional variable valve timing / lift mechanism is shown in FIG. 3 (the drawing shows an embodiment of the present invention, but the appearance thereof is the same as that of the conventional one, which is incorporated herein by reference).
As shown in, the low speed cam 11 with a small working angle or lift amount and the high speed cam 12 with a large working angle or lift amount.
A low speed rocker arm 3 that swings by a low speed cam 11 to open and close the intake valve 6; a high speed rocker arm 4 that swings by a high speed cam 12; And a hydraulic piston 52 that slides with the oil 7.

At low speed of the internal combustion engine, as shown in FIG. 13, the hydraulic piston 52 is actuated to the right by the coil spring 55, and the hydraulic action surface 57 at the right end contacts the inner end face 50 of the high pressure chamber. Since the restriction wall 43 of the high speed rocker arm 4 can enter the annular recess 59 near the left end, the high speed rocker arm 4 is separated from the low speed rocker arm 3. Therefore, high-speed rocker arm 4
Is oscillated by the high speed cam 12 independently, and the low speed rocker arm 3 is oscillated by the low speed cam 11 so that the intake valve 6
Open and close.

Further, at the time of high speed of the internal combustion engine, as shown in FIG. 14, from the hollow portion 21 of the rocker shaft 2 to the high pressure chamber 5.
The hydraulic oil 52 supplied to 6 operates the hydraulic piston 52 to the left, the hydraulic action surface 57 moves away from the inner end face 50, and the position of the annular recess 59 shifts.
Since the restriction wall 43 is engaged with the outer peripheral surface of the rocker arm 4, the high speed rocker arm 4 is connected to the low speed rocker arm 3. Therefore,
The high speed rocker arm 4 swings by the high speed cam 12,
The swing swings the low speed rocker arm 3 to open and close the intake valve 6.

[0005]

However, when the internal combustion engine is operating at a low speed, the entire area of the hydraulic action surface 57 of the hydraulic piston 52 is in contact with the inner end surface 50 of the high pressure chamber, so that the internal combustion engine shifts from a low speed to a high speed. It takes time for the hydraulic oil 7 to be supplied at some time to penetrate into the slight gap between the hydraulic pressure acting surface 57 and the inner end surface 50, and the hydraulic pressure on the hydraulic acting surface 57 is delayed from starting to act. Therefore, the initial speed of the hydraulic piston 52 operating to the left becomes slower, and the time (full stroke time) until the hydraulic piston 52 finishes operating to the left is, for example, about 45 msec. It was hanging.

As described above, when the full stroke time of the hydraulic piston 52 is long, the switching timing of the intake / exhaust valve 6 or the switching of the lift amount is delayed when the internal combustion engine shifts from low speed to high speed, and the response becomes poor. there were.
Further, if the initial speed of operation of the hydraulic piston 52 is slow as described above, the left end of the hydraulic piston 52 contacts the restriction wall 43 and is pushed back to the right in the initial operation, and it cannot be switched smoothly in one operation. There was also a problem that abnormal noise was generated at that time.

In order to solve the above problem, the present inventors initially studied to form a notch in the inner end surface 50 of the high pressure chamber 56 for allowing the hydraulic oil 7 to enter the hydraulic pressure acting surface 57. There is a new problem that the low-speed rocker arm 3 is difficult to machine and its strength is reduced.

An object of the present invention is to shorten the full stroke time by increasing the initial operating speed of the hydraulic piston, and to increase the opening / closing timing of the intake / exhaust valve or the switching speed of the lift amount when the internal combustion engine changes from low speed to high speed. As well as
It is possible to reduce the generation of abnormal noise when switching,
Further, it is to provide a new variable valve timing / lift mechanism which can be modified by a simple machining of the hydraulic piston and does not reduce the strength of the rocker arm.

[0009]

In order to achieve the above object, according to the present invention, a low speed rocker arm which swings by a low speed cam having a small operating angle or lift amount to open and close an intake / exhaust valve, and an operating angle or A high-speed rocker arm that swings with a high-speed cam with a large lift amount, and a hydraulic piston that separates the high-speed rocker arm from the low-speed rocker arm when the internal combustion engine is at low speed and connects the high-speed rocker arm to the low-speed rocker arm when the internal combustion engine is at high speed. In the provided variable valve timing / lift mechanism, a means for forming a notch for allowing hydraulic oil to enter the hydraulic action surface of the hydraulic piston is adopted.

The variable valve timing / lift mechanism of the present invention switches either the opening / closing timing of the intake / exhaust valve or the lift amount, or both. Therefore, the "low speed cam" and the "high speed cam" are: Any one or both of the working angle and the lift amount may be different. Further, this mechanism can be applied to either or both of the intake valve and the exhaust valve. The "notch" may have any shape as long as it allows hydraulic oil to penetrate into the hydraulic action surface. However, in order to remarkably increase the initial operating speed of the hydraulic piston, It is preferable that the notches occupy 20% or more of the total area.

[0011]

Since the notch is formed in the hydraulic action surface of the hydraulic piston, the hydraulic oil supplied when the internal combustion engine shifts from the low speed to the high speed immediately enters the outer peripheral edge of the hydraulic action surface from the notch. As a result, the hydraulic pressure starts to act on the hydraulic pressure acting surface faster than before. Therefore, the initial speed of operation of the hydraulic piston is increased, and the full stroke time until the operation is completed is shortened. When the full stroke time is shortened in this way, the opening / closing timing of the intake valve or the switching of the lift amount becomes faster when the internal combustion engine changes from low speed to high speed, and the response is improved. Also, when the initial operating speed of the hydraulic piston becomes faster, the end of the hydraulic piston does not contact the high-speed rocker arm and is pushed back at the beginning of operation, and the operation switches smoothly in one operation, preventing or reducing abnormal noise. To be done.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to an intake valve 2 per cylinder.
One embodiment embodying a variable valve timing / lift mechanism of a so-called four-valve internal combustion engine having two exhaust valves will be described with reference to FIGS.

As shown in FIGS. 3 to 5, in each cylinder-corresponding portion of the camshaft 1 for driving the intake valve, a base circle 11a and a nose 11b having a small working angle and a small lift amount are arranged on the right side of the portion. A low speed cam 11 is formed, and a high speed cam 1 including a base circle 12a and a nose 12b having a large working angle and a large lift amount is provided on the left side of the portion.
2 is formed. A hollow rocker shaft 2 arranged obliquely below the cam shaft 1 is rocked by a low speed rocker arm 3 which rocks by a low speed cam 11 to open and close two intake valves 6, and a high speed cam 12. A high-speed rocker arm 4 and a high-speed rocker arm 4 are pivotally attached to each other. Both rocker arms 3 and 4 are provided with a switching mechanism for disconnecting or connecting them.

The main body of the low-speed rocker arm 3 has left and right shaft mounting portions 31 through which the rocker shaft 2 is passed, right and center fork portions 32 extending forward from the right shaft mounting portion 31, and a left shaft mounting portion. Left fork part 3 extending forward from 31
2, a connecting portion 33 that connects the front ends of these fork portions 32, a mechanism housing portion 34 extending below the left and right shaft attachment portions 31, and a diagonally downward direction from the left front end portion of the mechanism housing portion 34. The spring receiving portion 35 and the spring receiving portion 35 are integrally formed in this embodiment. A roller 36 that contacts the low speed cam 11 while rotating to reduce friction loss is disposed in the space sandwiched by the right and center fork portions 32. As shown in FIG. It is pivotally attached via 37. Male screw pins 39 for pressing the two intake valves 6 are screwed into the female screw holes 38 formed at the right end and the left end of the connecting portion 33 so as to adjust the protrusion amount, and fixed by nuts.

The body of the high-speed rocker arm 4 includes a shaft-mounting portion 41 through which the rocker shaft 2 is inserted between the left and right shaft-mounting portions 31 of the low-speed rocker arm 3, and the shaft-mounting portion 41.
From the right end of the arm portion 42 as shown in FIG. 1 and FIG.
In the present embodiment, these parts are integrally formed. A hard tip 44 that abuts the high speed cam 12 is fixed to the upper surface of the arm portion 41. Arm part 42
Recesses 4 formed in the lower surface of the spring and the spring receiving portion 35, respectively.
A coil spring 45 is attached between 2a and 35a,
The high speed rocker arm 4 is always biased upward. An arcuate restriction surface 46 is formed at the lower end of the restriction wall 43.

The switching mechanism is shown in FIGS. 1 and 2 and 6 to 8.
As shown in, it is configured as follows. A cylinder hole 51 having a closed right end is formed inside the mechanism accommodating portion 34, and a hydraulic piston 52 is slidably inserted into the cylinder hole 51. A cylindrical stopper 53 is inserted near the left end of the cylinder hole 51, and is fixed by a stop ring 54 so that it cannot be pulled out. A coil spring 55 is mounted between the left end flange portion of the stopper 53 and the left end surface of the hydraulic piston 52 to constantly urge the hydraulic piston 52 to the right. The right end of the cylinder hole 51 is hydraulic oil 7
It is a high pressure chamber 56 in which the rocker shaft 2
In addition, the low speed rocker arm 3 is formed with oil holes 22 and 30 for communicating the hollow portion 21 of the rocker shaft 2 and the high pressure chamber 56. Further, a valve that closes at low speed of the internal combustion engine and opens at high speed is provided in an oil passage connecting a hydraulic pump (not shown) and the hollow portion 21 of the rocker shaft 2, and the hydraulic oil 7 pumped from the hydraulic pump is at high pressure only at high speed. It is adapted to be supplied to the chamber 56.

An annular and stepped notch 58 is formed on the outer peripheral edge of the right end surface, which is the hydraulic acting surface 57 of the hydraulic piston 52, for allowing the hydraulic oil 7 to quickly enter the outer peripheral edge of the hydraulic acting surface 57. Has been done. The hydraulic piston 52 of this embodiment
Has a diameter of 10 mm, and the width of the notch 58 in the radial direction is 2 mm.
8 occupy. The length of the notch 58 in the left-right direction is 2
mm.

An annular recess 59 for controlling the restriction wall 43 of the high speed rocker arm 4 is formed on the outer peripheral surface near the left end of the hydraulic piston 52. When the hydraulic piston 52 is actuated to the right by the coil spring 55, the restriction wall 43 of the high speed rocker arm 4 can enter the annular recess 59, so that the high speed rocker arm 4 is separated from the low speed rocker arm 3. .. Further, when the hydraulic piston 52 is operated to the left by the hydraulic oil 7, the position of the annular recess 59 is displaced and the outer peripheral surface of the hydraulic piston 52 abuts and engages with the restricting surface 46 of the restricting wall 42. The high speed rocker arm 4 is connected to the low speed rocker arm 3.

The variable valve timing / lift mechanism constructed as described above operates as follows. First, when the internal combustion engine is running at low speed, as shown in FIG. 1, the hydraulic piston 52 is actuated to the right by the coil spring 55, the hydraulic action surface 57 at the right end abuts the inner end face 50 of the high pressure chamber 56, and the left end is actuated. Since the restriction wall 43 of the high speed rocker arm 4 can enter the annular recess 59 in the vicinity, the high speed rocker arm 4 is separated from the low speed rocker arm 3.
Therefore, the high-speed rocker arm 4 independently swings freely by the high-speed cam 12, and the low-speed rocker arm 3 moves in the low-speed cam 1.
The intake valve 6 is swung by 1 to open and close the intake valve 6.

Further, when the internal combustion engine is operating at high speed, the valve is opened, so that the hydraulic oil 7 pressure-fed by a hydraulic pump (not shown) is valve 7 → hollow part 21 → oil hole 22 → oil hole 30.
And is supplied to the high pressure chamber 56. The hydraulic pressure of the hydraulic oil 7 causes the hydraulic piston 52 to move to the left as shown in FIG. 2, so that the hydraulic acting surface 57 is separated from the inner end surface 50, and
Since the position of the annular recess 59 is displaced and the regulation wall 43 abuts and engages with the outer peripheral surface of the hydraulic piston 52, the high speed rocker arm 4 is connected to the low speed rocker arm 3. Therefore,
The high speed rocker arm 4 swings by the high speed cam 12,
The swing swings the low speed rocker arm 3 to open and close the intake valve 6.

Since a notch 58 is formed in the hydraulic action surface 57 of the hydraulic piston 52 of this embodiment, the hydraulic oil 7 supplied when the internal combustion engine changes from low speed to high speed.
Immediately enters the outer peripheral edge of the hydraulic pressure acting surface 57 through the notch 58, and the hydraulic pressure starts to act on the hydraulic acting surface 57 faster than before. Therefore, the initial speed of actuation of the hydraulic piston 52 to the left becomes faster, and the full stroke time until the end of the actuation to the left is about 18 msec. Is shortened to.

When the full stroke time of the hydraulic piston 52 is shortened as described above, the opening / closing timing of the intake valve 6 and the switching of the lift amount are accelerated when the internal combustion engine changes from low speed to high speed, and the response is improved. Further, as described above, when the initial operating speed of the hydraulic piston 52 is increased, the left end of the hydraulic piston 52 is prevented from coming into contact with the restriction wall 43 of the high-speed rocker arm 4 and being pushed back to the right in the initial operation, and the single operation is performed. The smooth switching can prevent or reduce the generation of abnormal noise.

The present invention is not limited to the configuration of the above-described embodiment, but may be embodied by being modified without departing from the spirit of the invention, for example, as follows. (1) Change the shape of the notch 58 as follows, for example. First Modification Example: As shown in FIG. 9, a notch 58 is formed in an outer peripheral edge of a hydraulic action surface 57 of a hydraulic piston 52 in an annular and obliquely chamfered shape. Second Modification Example ... As shown in FIG.
A notch 58 formed in an annular and chamfered shape on the outer peripheral edge of the hydraulic action surface 57. Third Modification Example: As shown in FIGS. 11 and 12, a notch 58 formed in a cross groove shape on the hydraulic action surface 57 of the hydraulic piston 52. (2) Although the above embodiment is embodied as the intake valve 6, it should be applied to the exhaust valve.

[0024]

Since the variable valve timing / lift mechanism of the present invention is constructed as described above, the initial operating speed of the hydraulic piston is increased to shorten the full stroke time, and the internal combustion engine is shifted from low speed to high speed. In addition to speeding up the opening / closing timing of the intake / exhaust valve or the switching speed of the lift amount, it is possible to reduce the occurrence of abnormal noise at the time of switching, and the modification for that can be done by simple machining of the hydraulic piston. Therefore, it is possible to obtain the effect that the strength of the rocker arm is not reduced.

[Brief description of drawings]

FIG. 1 is a cross-sectional view taken along the line DD of FIG. 5 when an internal combustion engine is operating at a low speed, showing an embodiment of a variable valve timing / lift mechanism embodying the present invention.

FIG. 2 is a DD of FIG. 5 when the internal combustion engine is operating at high speed.
It is a line sectional view.

FIG. 3 is a perspective view showing the whole of the embodiment.

FIG. 4 is a plan view of the same embodiment.

FIG. 5 is a right side view of the same embodiment.

6 is a cross-sectional view taken along the line AA of FIG.

7 is a cross-sectional view taken along the line BB of FIG.

8 is a cross-sectional view taken along the line CC of FIG.

FIG. 9 is a side view showing a first modification of the notch of the hydraulic piston.

FIG. 10 is a side view showing a second modification of the notch of the hydraulic piston.

FIG. 11 is a side view showing a third modification of the notch of the hydraulic piston.

FIG. 12 is an end view of FIG.

FIG. 13 is a cross-sectional view showing a conventional example of a variable valve timing / lift mechanism when an internal combustion engine is operating at a low speed.

FIG. 14 is a sectional view of a conventional example of the internal combustion engine at high speed.

[Explanation of symbols]

3 Low-speed rocker arm 4 High-speed rocker arm 6 Intake valve 7 Hydraulic oil 11 Low-speed cam 12 High-speed cam 52 Hydraulic piston 57 Hydraulic action surface 58 Notch

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[Procedure amendment]

[Submission date] January 31, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be amended] Claims

[Correction method] Change

[Correction content]

[Claims]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] 0002

[Correction method] Change

[Correction content]

[0002]

Conventional variable valve timing lift mechanism, as shown in FIGS. 13 to 15, and two low-speed cam 111 small working angle or lift amount, one large operating angle or lift amount of the high-speed Cam 112 and each low speed cam
111 swung by two intake valves 106 (exhaust Bas
(Although it may be a lube) , the left and right low-speed rocker arms 103 for opening and closing, and the central high-speed cam 112 for rocking
And one high-speed rocker arm 104, these rocker
The switching mechanism 105 provided in the frames 103 and 104.
I have it. The switching mechanism 105 includes each rocker arm 10
Provided so as to be divided at their boundaries in the width direction of 3,104
Cylinder hole 151 and left of the cylinder hole 151
Is slidably inserted into the low speed rocker arm 103 on the side.
Similarly, the first hydraulic piston 152a and the high-speed rocker arm
Second hydraulic piston slidably inserted in the chamber 104
152b and inside the low-speed rocker arm 103 on the right side as well
Is slidably inserted in the
Stopper pin 153 biased to the left and low speed on the left
An oil hole 130 formed in the rocker arm 103
ing.

[Procedure 3]

[Document name to be amended] Statement

[Name of item to be corrected] 0003

[Correction method] Change

[Correction content]

At low speed of the internal combustion engine, as shown in FIG. 14 , the first and second hydraulic pistons 152a, 152a,
152b is actuated to the left by the coil spring 155, and the low speed rocker arm 103 and the high speed on the left side , respectively.
The high-speed rocker arm 104 is separated from the low-speed rocker arm 103 because the high-speed rocker arm 104 is accommodated in the low-speed rocker arm 104 . Therefore, the high-speed rocker arm 104 is connected to the high-speed cam 1
12 rocks independently and rocks for low speed rocker arm 103
Swings by the low speed cam 111 to open and close the intake valve 106 . At this time, the left end of the first hydraulic piston 152a
The hydraulic action surface 157 of the abutting against the inner end surface 150 of the high pressure chamber.
There is.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0004

[Correction method] Change

[Correction content]

Further, at the time of high speed of the internal combustion engine, as shown in FIG. 15 , oil is discharged from the hollow portion 121 of the rocker shaft 102.
Hydraulic oil 107 supplied to the high pressure chamber 156 through the hole 130
Causes the hydraulic action surface 157 to separate from the inner end surface 150, and
The first and second hydraulic pistons 152a, 152b are moved to the right.
The rocker arm 103 for low speed and the high speed
Boundary with rocker arm 104 for high speed, rocker arm 1 for high speed
04 and the right low-speed rocker arm 103
Therefore , the high speed rocker arm 104 is connected to the low speed rocker arm 103 . Therefore, the high-speed cam 112
The rocking of the rocker arm 104 for high speed rocks the rocker arm 103 for low speed to open and close the intake valve 106 .

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0005

[Correction method] Change

[Correction content]

[0005]

However, the above-mentioned variable
The valve timing lift mechanism has two intake valves 1
Two low-speed rocker rockers on the left and right to open and close 06
Frame 103 and one high-speed rocker arm 104 in the center.
Since a total of 3 rocker arms were used, the intake valve
The distance between the valves 106 is increased, and the internal combustion engine can be made compact.
The first problem was that there wasn't one.

[Procedure Amendment 6]

[Document name to be amended] Statement

[Correction target item name] 0006

[Correction method] Change

[Correction content]

As a second problem, the cylinder hole 15
1 is divided at the boundary of each rocker arm 103, 104
Therefore, when the internal combustion engine transitions from low speed to high speed,
The right peripheral portion of the pressure piston 152a is the rocker arm 1 for high speed.
It collided with the left peripheral part of the cylinder hole 151 in 04.
The right peripheral portion of the second hydraulic piston 152b is on the right side at low speed.
Left side of the cylinder hole 151 in the rocker arm 103 for use
If it collides with the edge, it switches smoothly with one operation.
No contact, abnormal noise, or worn contact
There was a possibility that Moreover, when the internal combustion engine is operating at low speed,
The entire hydraulic action surface 157 of one hydraulic piston 152a is high.
Since it is in contact with the inner end surface 150 of the pressure chamber, transition to high speed
At some times, the hydraulic oil 107 causes the hydraulic pressure acting surface 157 and the inner end surface 150 to
It takes time to penetrate into the slight gap of the
The start of hydraulic pressure on the work surface 157 is delayed. That
To the right of the first and second hydraulic pistons 152a, 152b.
The initial velocity of the
The ability was increasing. In addition, the first and second hydraulic fixers
The time until the end of the operation of the valves 152a and 152b to the right
(Full stroke time) becomes longer, so shift to high speed
Sometimes the intake valve opening / closing timing or lift amount
There is also a problem that switching is delayed and response becomes poor.
It was

[Procedure Amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0007

[Correction method] Change

[Correction content]

Recently, the second problem has been solved.
Of the hydraulic piston in the low-speed rocker arm.
A variable valve that is provided without breaking the solder hole on the way.
Although a timing and lift mechanism has been disclosed (Japanese Patent Application Laid-Open No. HEI 3-
No. 43612), the disclosure is still left and right.
Low speed rocker arm and one central high speed rocker arm
It used a total of three rocker arms called Mu.
Therefore, the first problem could not be solved at all.

[Procedure Amendment 8]

[Document name to be amended] Statement

[Correction target item name] 0008

[Correction method] Change

[Correction content]

The object of the present invention is to solve the first problem.
The low-speed rocker arm opens and closes the two valves.
Requires only one rocker arm for high speed and one for high speed, and the structure is simple
As the valve becomes closer, the
New variable valve timing that can be compacted
To provide a lifting and lifting mechanism. Also, the present invention
Another object of the present invention is to solve the second problem, and
Opening and closing timing of the valve when shifting from high speed to high speed
Or speed up the switching of the lift amount and make it smoother
To reduce abnormal noise and wear.

[Procedure Amendment 9]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

[Correction content]

[0009]

In order to achieve the above object, the present invention provides one low-speed rocker arm that swings and opens and closes a valve by a low-speed cam having a small operating angle or lift, and an operating angle or A switching mechanism that separates one high-speed rocker arm that swings by a high-speed cam with a large lift amount and the high-speed rocker arm from the low-speed rocker arm when the internal combustion engine is at low speed, and connects the high-speed rocker arm to the low-speed rocker arm when the internal combustion engine is at high speed. a variable valve timing lift mechanism with the door, lock for said low-speed
Kaarm is for one low speed provided on one side in the width direction
Cam contact part and one high speed provided on the other side in the width direction
Rocker arm accommodating part for use, and provided at both ends in the width direction
The high-speed rocker arm having two valve pressing parts
Is equipped with one high-speed cam contact part,
The rocker arm accommodating portion is swingably disposed, and the switching machine
The structure is divided in the width direction of the low speed rocker arm.
Without a cylinder hole, and in the middle of the cylinder hole
An opening provided to open to the high-speed rocker arm housing.
It is slidably inserted into the mouth and the cylinder hole,
The rocker arm for high speed that swings at low speed does not come into contact
The rocker arm for high speed that swings at high speed of the combustion engine opens
And a hydraulic piston that comes into contact with the hydraulic piston.
The hydraulic oil is applied to the hydraulic operating surface of the ton.
It is characterized in that a notch for forming is formed.

[Procedure Amendment 10]

[Document name to be amended] Statement

[Correction target item name] 0011

[Correction method] Change

[Correction content]

[0011]

[Operation] The low-speed rocker arm has two widthwise end portions.
With two valve pressing parts, the high-speed rocker arm
High-speed rocker arm housing formed on the high-speed rocker arm
Since it is swingably installed in the section, two valves can be opened.
Low speed rocker arm and high speed rocker arm to close
Only one for each, the structure is simple and the valve
Are approaching each other. In addition, in the switching mechanism,
The ton cylinder hole is halfway in the width direction of the low-speed rocker arm.
Since it is installed without being divided by the internal combustion engine
When moving from low speed to high speed, the hydraulic piston
Sliding and switching smoothly without colliding with the hole.
Moreover, since the hydraulic piston has a notch formed on the hydraulic action surface, the hydraulic oil supplied at the time of shifting to high speed immediately enters the outer peripheral edge of the hydraulic action surface from the notch, and the hydraulic pressure is applied to the hydraulic action surface. Will start to work faster than before. Therefore, the hydraulic piston operating the initial velocity becomes fast, full stroke time to finish working is Ru is shortened.

[Procedure Amendment 11]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Change

[Correction content]

The main body of the low-speed rocker arm 3 has left and right shaft mounting portions 31 through which the rocker shaft 2 is passed, right and center fork portions 32 extending forward from the right shaft mounting portion 31, and a left shaft mounting portion. Left fork part 3 extending forward from 31
2, a connecting portion 33 that connects the front ends of these fork portions 32, a mechanism housing portion 34 extending below the left and right shaft attachment portions 31, and a diagonally downward direction from the left front end portion of the mechanism housing portion 34. The spring receiving portion 35 and the spring receiving portion 35 are integrally formed in this embodiment. In the space sandwiched by the right and central fork portions 32, rollers 36 that are in contact with the low speed cam 11 while rotating to reduce friction loss are arranged. As shown in FIG. A bearing 37 is rotatably attached to the shaft. one
The space surrounded by the fork parts 32 on the left, the center, and the left is high.
It serves as a rocker arm housing for speed. A male screw pin 39 as a valve pressing portion for pressing the two intake valves 6 is screwed into each female screw hole 38 formed at the right end and the left end of the connecting portion 33 so as to adjust the protrusion amount and fixed by a nut. There is.

[Procedure Amendment 12]

[Document name to be amended] Statement

[Correction target item name] 0015

[Correction method] Change

[Correction content]

The high speed rocker arm 4 is for the low speed rocker arm 4.
Rocker arm 3 can be swung to the high-speed rocker arm housing
It is installed in. That is, the main body of the high-speed rocker arm 4 includes a shaft mounting portion 41 through which the rocker shaft 2 is inserted between the left and right shaft mounting portions 31 of the low speed rocker arm 3, and an arm portion 42 extending forward from the shaft mounting portion 41. As shown in FIGS. 1 and 7, it comprises a restriction wall 43 extending downward from the right end of the arm portion 42, and in the present embodiment, these portions are integrally formed. The upper surface of the arm portion 4 2 hard tip 44 in contact with the high-speed cam 12 is fixed.
A coil spring 45 is provided between the lower surface of the arm portion 42 and the recesses 42a and 35a formed in the spring receiving portion 35, respectively.
Is mounted, and always urges the high-speed rocker arm 4 upward. In addition, the lower end of the restriction wall 43 has an arcuate restriction surface 4
6 is formed.

[Procedure Amendment 13]

[Document name to be amended] Statement

[Correction target item name] 0016

[Correction method] Change

[Correction content]

The switching mechanism is shown in FIGS. 1 and 2 and 6 to 8.
As shown in, it is configured as follows. Inside the mechanism accommodating portion 34, it is not divided in the width direction on the way.
A cylinder hole 51 is formed, which extends so that its right end is closed, and a hydraulic piston 52 is slidably inserted into the cylinder hole 51. A cylindrical stopper 53 is inserted near the left end of the cylinder hole 51, and is fixed by a stop ring 54 so that it cannot be pulled out. A coil spring 55 is mounted between the left end flange portion of the stopper 53 and the left end surface of the hydraulic piston 52 to constantly urge the hydraulic piston 52 to the right. The right end of the cylinder hole 51 is a high pressure chamber 56 into which the hydraulic oil 7 enters, and the rocker shaft 2 and the low speed rocker arm 3 have oil holes 22 and 30 for communicating the hollow portion 21 of the rocker shaft 2 with the high pressure chamber 56. Are formed. Further, a valve that closes at low speed of the internal combustion engine and opens at high speed is provided in an oil passage connecting a hydraulic pump (not shown) and the hollow portion 21 of the rocker shaft 2, and the hydraulic oil 7 pumped from the hydraulic pump is at high pressure only at high speed. It is adapted to be supplied to the chamber 56.

[Procedure Amendment 14]

[Document name to be amended] Statement

[Correction target item name] 0018

[Correction method] Change

[Correction content]

A high speed roller is provided in the middle of the cylinder hole 51.
I split the cylinder in half so that it opens to the housing
An opening having a rugged shape is formed. Further, the outer peripheral surface near the left end of the hydraulic piston 52 is an annular recess 59 for controlling the restriction wall 43 of the high speed rocker arm 4 is formed. When the hydraulic piston 52 is actuated to the right by the coil spring 55, the restriction wall 43 of the high speed rocker arm 4 passes through the opening in the annular recess 59.
Since the possible intrusion Te, the high speed rocker arm 4 is disconnected from the low speed rocker arm 3. When the hydraulic piston 52 is actuated to the left by the hydraulic oil 7, the position of the annular recess 59 is displaced so that the restriction surface 46 of the restriction wall 42 abuts and engages the outer peripheral surface of the hydraulic piston 52 via the opening. For matching, the high speed rocker arm 4 is connected to the low speed rocker arm 3.

[Procedure Amendment 15]

[Document name to be amended] Statement

[Correction target item name] 0021

[Correction method] Change

[Correction content]

The low speed rocker arm 3 of this embodiment is
With male threads as two valve pressing parts at both ends in the width direction
High speed rocker arm 4 with pin 39, low speed rocker arm 4
Swing in the high-speed rocker arm housing formed on the arm 3.
It is possible to open and close the two intake valves 6
To do this, low-speed rocker arm 3 and high-speed rocker arm
4 is required for each one, the structure is simple and both
The air valve 6 can be closely spaced,
It can be made compact.

[Procedure 16]

[Document name to be amended] Statement

[Name of item to be corrected] 0022

[Correction method] Change

[Correction content]

In the switching mechanism, the hydraulic piston 5
2 cylinder holes 51 in the width direction of the low speed rocker arm 3
Since it is installed without being divided in the middle,
During the transition from low speed to high speed, the hydraulic piston 52
Sliding without colliding with any of the cylinder holes 51,
Smooth opening and closing timing of intake valve 6 and lift amount
, The abnormal noise is generated and the hydraulic piston 52 and
The wear of the solder holes 51 is reduced. Moreover, the hydraulic piston 5
The notch 58 is formed in the hydraulic action surface 57 of the second
Therefore, the hydraulic oil 7 supplied at the time of the transition is the oil from the notch 58.
Immediately enters the outer peripheral edge of the pressure acting surface 57, and the hydraulic acting surface 5
The hydraulic pressure starts to act on 7 faster than before. That
Therefore, the initial speed of actuation of the hydraulic piston 52 to the left becomes faster,
The switching becomes smoother. Also, the hydraulic piston 5
The full stroke time until 2 has finished operating to the left is about
18 msec. Since it is shortened to
The response is improved.

[Procedure Amendment 17]

[Document name to be amended] Statement

[Correction target item name] 0024

[Correction method] Change

[Correction content]

[0024]

Since the variable valve timing / lift mechanism of the present invention is configured as described above, it has two valves.
To open and close the, low-speed rocker arm and high-speed rocker arm
Only one for each, simplifying the structure and
Aiming to make the internal combustion engine compact by making the distance between the lubes closer
be able to. In addition, the transition from low speed to high speed of internal combustion engine
Sometimes the valve opening / closing timing or lift amount is high.
It switches smoothly and reduces abnormal noise and wear.

[Procedure 18]

[Document name to be amended] Statement

[Name of item to be corrected] Fig. 13

[Correction method] Change

[Correction content]

FIG. 13 is a perspective view showing an entire conventional example of a variable valve timing / lift mechanism.

[Procedure Amendment 19]

[Document name to be amended] Statement

[Name of item to be corrected] Fig. 14

[Correction method] Change

[Correction content]

FIG. 14 is a sectional view of a conventional example when the internal combustion engine is operating at a low speed.

[Procedure amendment 20]

[Document name to be amended] Statement

[Correction target item name] Fig. 15

[Correction method] Added

[Correction content]

FIG. 15 is a sectional view of a conventional example when the internal combustion engine is operating at high speed.

[Procedure correction 21]

[Document name to be amended] Statement

[Correction target item name] Explanation of code

[Correction method] Change

[Correction content]

[Explanation of symbols] 3 low speed rocker arm 4 high speed rocker arm 6 intake valve 11 low speed cam 12 high speed cam 36 roller as low speed cam abutment 39 male screw pin as valve pressing part 43 restriction wall 44 high speed cam Hard tip as contact part 46 Restriction surface 51 Cylinder hole 52 Hydraulic piston 57 Hydraulic action surface 58 Notch

[Procedure correction 22]

[Document name to be corrected] Drawing

[Name of item to be corrected] Fig. 13

[Correction method] Change

[Correction content]

[Fig. 13]

[Procedure amendment 23]

[Document name to be corrected] Drawing

[Name of item to be corrected] Fig. 14

[Correction method] Change

[Correction content]

FIG. 14

[Procedure amendment 24]

[Document name to be corrected] Drawing

[Correction target item name] Fig. 15

[Correction method] Added

[Correction content]

FIG. 15

Claims (1)

[Claims] 1. A low-speed rocker arm that swings by a low-speed cam having a small operating angle or lift amount to open and close an intake / exhaust valve, and a high-speed rocker arm that swings by a high-speed cam having a large operating angle or lift amount. In a variable valve timing / lift mechanism having a hydraulic piston that separates the high-speed rocker arm from the low-speed rocker arm when the internal combustion engine is at low speed, and connects the high-speed rocker arm to the low-speed rocker arm when the internal combustion engine is at high speed, the hydraulic action of the hydraulic piston A variable valve timing / lift mechanism, characterized in that a notch for allowing hydraulic oil to penetrate into the hydraulic action surface is formed on the surface.