JPH11280437A - Variable valve system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a variable valve system which can set in a wide range the lift quantity of a valve element to a valve seat and also has satisfactory responsiveness. SOLUTION: This variable valve system is equipped with a first cylinder body 4, a first piston 5 arranged in a first cylinder hole 4a, a valve element 3b brought into contact with and separated from a valve seat 3a accompanied by the movement of a lifter 6, a valve driving cam 7 and the first cylinder body 4, a second cylinder body 8, a second piston 9 arranged in a second cylinder hole 8a, a control cam 10 and a communicating passage 17. An introducing amount of hydraulic fluid introduced to a first pressure chamber 15 is controlled, thereby distance between the abutting parts of the first piston 5 and lifter 6 can be controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable valve operating apparatus for variably controlling a valve lift.

[0002]

2. Description of the Related Art A conventional variable valve apparatus is disclosed in
As disclosed in JP-A-324611, a cylinder body having a bottomed cylindrical shape having a cylinder hole extending in a vertical direction and having a lower side opened and disposed in a housing so as to be movable in a vertical direction, A plate portion provided integrally with the cylinder body so as to close the opening of the hole and having a hole having a diameter smaller than the diameter of the cylinder hole; and a plate portion having a diameter smaller than the diameter of the cylinder hole. A body having a diameter greater than the diameter;
A projection is provided on the lower surface of the main body and inserted into the hole, and a projection is provided on the upper surface of the main body and can contact an upper bottom surface of the cylinder body. The piston is provided movably in the up and down direction, and the protrusion projects downward from the hole in accordance with the movement in the cylinder hole. A first position where the projection of the piston contacts the upper bottom surface of the cylinder body and a lower surface of the projection is flush with a lower surface of the plate; Control means for selectively controlling the lower surface of the portion to be in contact with the upper surface of the plate so that the convex portion projects downward from the hole to a second position; and moving the cylinder body downward. Moving means for moving downwardly the piston with said cylinder body integrally by a,
A valve body that comes into contact with and separates from a valve seat as the piston moves with the movement of the cylinder body.

In this conventional variable valve device, when the control means does not fill the cylinder hole with the working fluid, the position of the piston with respect to the valve body is set to the first position, and the distance between the valve body and the valve seat is reduced. The state is set to the low lift state. On the other hand, when the control means fills the cylinder hole with the working fluid, the position of the piston with respect to the cylinder body is set to the second position, and the distance between the valve body and the valve seat is set to the high lift state.

[0004]

In this conventional variable valve operating apparatus, the amount of separation between the valve seat and the valve body obtained by the operation of the control means is only two for the low lift and the high lift. However, in recent years, there has been a demand for a variable valve operating device capable of setting a lift amount of a valve body with respect to a valve seat in a wider range, and the above-described conventional variable valve operating device may not be able to cope with the problem.

Further, in this conventional variable valve operating apparatus, when the control means fills the cylinder hole with the working fluid and sets the position of the piston relative to the cylinder body to the second position, the cylinder hole starts to be filled with the working fluid. Until the working fluid reaches between the upper surface of the main body of the piston and the upper bottom surface of the cylinder body, the working fluid does not cause the piston to move downward with respect to the cylinder body. That is, it did not have good responsiveness.

It is an object of the present invention to provide a variable valve operating apparatus which can set a lift amount of a valve body with respect to a valve seat in a wider range and has good responsiveness.

[0007]

In order to solve the above-mentioned problems, a first cylinder body having a first cylinder hole and disposed in a housing so as to be able to move forward and backward is provided. A first piston, which is disposed so as to be capable of forming a first pressure chamber in front of the first pressure chamber, and is capable of abutting on the first piston, and biases the first piston forward to allow the first piston to move forward in the first pressure chamber. A first moving means for advancing the first cylinder body via a working fluid; and a first piston and the first moving means by controlling an amount of the working fluid introduced into the first pressure chamber. A variable valve actuating device comprising a control means for controlling the distance between the contact portions of the valve body and a valve element which comes into contact with and separates from the valve seat as the first cylinder body moves.

Preferably, the control means includes a second cylinder body having a second cylinder hole, a second cylinder body provided in the second cylinder hole so as to be able to move forward and backward and forming a second pressure chamber in front of the second cylinder body. It is preferable that the variable valve device include two pistons, a second moving unit that advances the second piston, and a communication path that communicates the first pressure chamber and the second pressure chamber.

Preferably, the communication passage includes a valve member capable of cutting off communication between the first pressure chamber and the second pressure chamber.
The second communication means communicates with the communication passage between the valve seat member and the second pressure chamber, and the second movement means moves the second movement chamber.
It is desirable that the variable valve device be provided with a pressure accumulating chamber capable of storing the working fluid flowing out of the pressure chamber.

Preferably, the second moving means is a variable valve operating device which is a cam.

Preferably, the second moving means is a cam, and the first cylinder body, the first piston, the valve seat, the valve body, the second cylinder body, the second piston, the communication passage, And a variable valve apparatus in which a plurality of units including at least the cams are provided, and the cams of the respective units are arranged on a single shaft.

Preferably, the diameter of the first piston is substantially equal to the diameter of the first cylinder hole.

According to the first aspect of the present invention, when the control means is operated, the distance between the contact portions of the first piston and the first moving means is controlled, and the distance between the valve body and the valve seat is reduced. Controlled.

According to a second aspect of the present invention, in addition to the first aspect, the amount of the working fluid introduced into the first pressure chamber is controlled by moving the second piston by the second moving means. .

According to a third aspect of the present invention, in addition to the second aspect, the working fluid flowing out of the second pressure chamber is temporarily stored in the accumulator.

The function of claim 4 is the function of claim 2 or claim 3.
In addition to the operation described above, the second piston is moved by operating the cam.

According to the fifth aspect, in addition to the second aspect, a plurality of units are simultaneously controlled by driving only one shaft provided with a plurality of cams.

The function of claim 6 is the same as the function of any one of claims 1 to 5, except that the first cylinder bore has a first cylinder hole.
The piston forms a first pressure chamber only in front of it.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to embodiments.

FIG. 1 is a sectional view of a main part of an internal combustion engine using a variable valve apparatus 1 according to one embodiment of the present invention. The variable valve operating device 1 includes a housing 2, an intake / exhaust valve 3, a first cylinder body 4, a first piston 5, a lifter 6, a valve drive cam 7, a second cylinder body 8, and a second piston. 9, a control cam 10, an oil passage valve 11, and a reservoir 12.

The housing 2 has an assembling hole 2a extending vertically (in the vertical direction in FIG. 1). The housing 2 is provided with a valve seat 3 a of the intake / exhaust valve 3. The valve seat 3a communicates with a gas passage (not shown) communicating with the mounting hole 2a.

The valve body 3b of the intake / exhaust valve 3 is disposed in the mounting hole 2a so as to be able to reciprocate in its axial direction (vertical direction in FIG. 1). A valve spring 13 is provided between a retainer integrally provided on the valve body 3b and a stepped portion of the mounting hole 2a, and the valve body 3b is always closed by the valve spring 13 in the closing direction of the intake / exhaust valve 3. That is, it is urged upward in FIG.

In the assembling hole 2a, a first cylinder body 4 having a bottomed cylindrical shape having a first cylinder hole 4a extending in a vertical direction and opening at an upper side thereof is provided. The first cylinder body 4 is integrally connected at its lower end surface to the upper end of the valve body 3b, and is capable of moving up and down the mounting hole 2a integrally with the valve body 3b.

The first cylinder hole 4 of the first cylinder body 4
The first piston 5 is disposed at a so as to be able to move up and down in the first cylinder hole 4a. The diameter of the first piston 5 is substantially equal to the diameter of the first cylinder hole 4a, and the first pressure chamber 1 is provided in the first cylinder hole 4a below the first piston 5.
5 are formed.

Above the first piston 5, a lifter 6 and a first
A valve driving cam 7 is provided. Lifter 6 and 1st
The drive cam 7 constitutes a first moving means 14. The lifter 6 is disposed on the housing 2 so as to be able to move up and down, and can be brought into contact with the upper surface of the first piston 5 by a projection formed on the lower surface thereof. A spring 18 is provided between the lower surface of the lifter 6 and the upper surface of the piston 5, and the first piston 5 and the lifter 6 are urged by the spring 18 so as to be separated from each other.

The housing 2 is integrally provided with a second cylinder body 8, and the second cylinder body 8 has a second cylinder hole 8a extending vertically. A second piston 9 is provided in the second cylinder hole 8a so as to be vertically movable. The second piston 9 forms a second pressure chamber 16 below the second cylinder hole 8a. Above the second piston 9, there is provided a second piston 9 for moving the second piston 9 downward.
A control cam 10 as a moving means is provided.

The housing 2 has a first pressure chamber 15 and a second pressure chamber 15.
A communication passage 17 for communicating with the pressure chamber 16 is formed. The first cylinder body 4 has a communication hole 4b for communicating the first pressure chamber 15 with the communication passage 17.

An oil passage valve 11 is provided in the communication passage 17, and a reservoir 12 is provided between the oil passage valve 11 and the second pressure chamber 16. The oil passage valve 11 includes the intake / exhaust valve 3
Depending on the lift state of the cylinder and the pressure accumulation state of the reservoir 12.
The communication between the pressure chamber 15 and the second pressure chamber 16 and the pressure accumulation chamber 12 is established and cut off.

The reservoir 12 is formed integrally with the housing 2, a bore 12 b formed in the body 12 a and extending in the up-down direction, and disposed in the bore 12 b so as to be movable in the up-down direction. A third piston 12d that forms a pressure accumulation chamber 12c below the bore 12b is provided, and a spring 12e that is disposed inside the bore 12b and urges the third piston 12d downward. The accumulation chamber 12c
The communication passage 17 is provided between the oil passage valve 11 and the second pressure chamber 16.

Next, the operation of the variable valve operating device 1 will be described. In the initial state shown in FIG. 1, the lower end of the valve body 3b is in contact with the valve seat 3a, so that the intake / exhaust valve 3 takes a closed state, and the communication between the gas passage and the outside of the housing 2 is cut off. I have.

The oil passage valve 11 blocks communication between the first pressure chamber 15, the second pressure chamber 16, and the pressure accumulating chamber 12c. or,
The second piston 9 is at the retreat limit position with respect to the second cylinder body 12a.
The position of the piston 12d with respect to the body 12a is a position where the spring 19 is not bent. That is, the working fluid is not accumulated in the reservoir 12.

In the initial state shown in FIG. 1, a predetermined clearance exists between the lower end surface of the projection formed on the lower surface of the lifter 6 and the upper end surface of the first piston 5 in the first pressure chamber 15. As such, a working fluid is introduced.

When the valve drive cam 7 is rotated, for example, clockwise in FIG. 1, the lifter 6 is advanced downward with respect to the housing 2. When the lifter 6 advances by the clearance between the lifter 6 and the first piston 5 against the urging force of the spring 18, the protrusion of the lifter 6 comes into contact with the first piston 5 and moves the first piston 5 downward with respect to the housing 2. To move forward.

When the lifter 6 and the first piston 5 are integrally advanced, the first cylinder body 4 is also advanced downward with respect to the housing 2 through the working fluid in the first pressure chamber 15, and As the one cylinder body 4 advances, the valve body 3b also moves downward with respect to the housing 2 against the urging force of the valve spring 13, that is, in the opening direction of the intake / exhaust valve 2. Accordingly, the movement of the valve body 3b causes the valve body 3b to move to the valve seat 3a.
, The intake / exhaust valve 3 is opened, and the gas passage is communicated with the outside of the housing 2.

When the valve driving cam 7 continues to rotate and its apex portion comes into contact with the rear end face of the lifter 6, the distance between the valve body 3b and the valve seat 3a, that is, the lift amount becomes maximum. When the apex portion of the valve driving cam 7 passes through the rear end surface of the lifter 6, the valve body 3b
Is retracted upward with respect to the housing 2.

When the valve body 3b is moved upward with respect to the housing 2, that is, in the closing direction of the intake / exhaust valve 3, the first
The cylinder body 4 is retracted upward in the mounting hole 2a, and the first piston 5 and the lifter 6 are also retracted with the retraction of the first cylinder body 4.

Accordingly, the valve body 3b comes into contact with the valve seat 3a, and the intake / exhaust valve 3 is closed, and the gas passage is shut off from the outside of the housing 2. After the valve body 3b comes into contact with the valve seat 3a, the retreat of the first cylinder body 4 and the first piston 5 also ends with the end of the movement of the valve body 3b in the closing direction of the intake / exhaust valve 3, and the lifter 6 Is moved upward by the spring 18 and returned to the initial position shown in FIG.

For example, in order to adjust the lift amount of the intake / exhaust valve 3 according to the operation state of the internal combustion engine, the control cam 10 is controlled by a step motor (not shown) controlled by an electronic control unit (not shown) for controlling the internal combustion engine. Is rotated by a predetermined amount, for example, clockwise in FIG.
Is advanced downward in the second cylinder hole 8a. When the second piston 9 is advanced, the second pressure chamber 16
The working fluid inside is discharged to the communication passage 17.

At this time, by operating the oil passage valve 11, the first
The communication between the pressure chamber 15 and the second pressure chamber 16 is cut off, and the working fluid flowing out of the second pressure chamber 16 flows into the pressure accumulating chamber 12 c of the reservoir 12. The working fluid flowing into the pressure accumulating chamber 12c urges the third piston 12d upward against the body 12a against the urging force of the spring 19. That is, the pressure generated in accordance with the rotation of the control cam 10 or the movement of the second piston 9 is stored in the reservoir 12.

When the reservoir 12 is in the pressure accumulating state and the oil passage valve 1
When 1 is in the shut-off state, when the lift amount of the intake / exhaust valve 3 becomes 0, that is, the valve body 3b comes into contact with the valve seat 3a,
When the first cylinder body 4 is at the retreat limit position with respect to the housing 2, the oil passage valve 11 is operated to be in an open state, so that the first pressure chamber 15 and the pressure accumulating chamber 12c are in a communicating state. .

Therefore, the working fluid in the pressure accumulating chamber 12c flows into the first pressure chamber 15 via the communication passage 17, the oil passage valve 11, and the communication hole 4b. When the working fluid flows into the first pressure chamber 15, the pressure in the first pressure chamber 15 increases, and the first piston 5 retreats upward with respect to the cylinder body 4 against the urging force of the spring 18. Is done.

The amount of retreat of the first piston 5 is determined by the pressure accumulating chamber 12c.
Pressure stored in the control cam 1
It depends on the rotation angle of 0, and the clearance between the lifter 6 and the first piston is reduced by retreating the first piston 5. In the reservoir 12, the pressure stored by the working fluid in the pressure accumulating chamber 12c flowing to the first pressure chamber 15 becomes zero, and FIG.
To the initial state. Further, as the reservoir 12 returns to the initial state, the oil passage valve 11 is closed, and the communication between the first pressure chamber 15 and the pressure accumulating chamber 12c is cut off.

With the working fluid flowing from the pressure accumulating chamber 12c into the first pressure chamber 15 and the clearance between the first piston 5 and the lifter 6 being reduced by a predetermined amount, the valve driving cam 7 is moved as described above. When rotated, the clearance between the first piston 5 and the lifter 6 is reduced, so that the amount of advance of the first cylinder body 4 with respect to the housing 2 and the amount of advance of the valve body 3b with respect to the housing 2 are increased. You. Therefore, the lift amount of the intake / exhaust valve 3 is increased.

In particular, when the apex portion of the control cam 10 comes into contact with the rear end face of the second piston 9, the reservoir 12
The pressure stored in the pressure accumulating chamber 12c becomes maximum, and when the maximum pressure stored in the pressure accumulating chamber 12c flows into the first pressure chamber 15, the clearance between the first piston 5 and the lifter 6 becomes zero. The first piston 5 is retracted with respect to the first cylinder body 4 until. In this state, the lift amount of the intake / exhaust valve 3 associated with the operation of the valve drive cam 7 becomes the maximum.

When the lift amount of the intake / exhaust valve 3 is reduced from the state where the lift amount of the intake / exhaust valve 3 is maximized, when the intake / exhaust valve 3 takes a closed state, that is, when the first cylinder body 4 is retracted relative to the housing 2. When the position becomes the position, the oil passage valve 11 is opened, and the first pressure chamber 15 and the second pressure chamber 16 are connected to each other.

Next, for example, when the control cam 10 is rotated counterclockwise to the state shown in FIG. 1, the second piston 9 can be moved upward with respect to the second cylinder body 8. Therefore, the working fluid in the first pressure chamber 15 flows through the communication hole 4b, the oil passage valve 11,
Through the second pressure chamber 16. Therefore, the pressure in the first pressure chamber 15 decreases and the first piston 5
Is moved downward with respect to the first cylinder body 4 by the spring 18, and the first piston 4 returns to the state shown in FIG.

The flow of the working fluid from the first pressure chamber 15 into the second pressure chamber 16 moves the second piston 9 upward with respect to the second cylinder body 8a, and the second piston 9 is also shown in FIG. Return to the initial position.

As described above, according to the present invention, by changing the rotation angle of the control cam 10, the first
By increasing or decreasing the amount or pressure of the working fluid introduced into the pressure chamber 15 to increase or decrease the distance between the contact portions between the first piston 5 and the lifter 6, the lift amount of the intake / exhaust valve 3 can be steplessly adjusted. Can be increased or decreased.

Further, when the working fluid is increased or decreased in the first pressure chamber 15, the clearance between the first piston 5 and the lifter 6 is immediately increased or decreased, and the lift amount of the intake / exhaust valve 3 is immediately set. Because it is possible, the responsiveness of the variable valve operating device 1 can be improved.

Therefore, it is possible to set the lift amount of the valve body 3b with respect to the valve seat 3a in a wider range, and to provide the variable valve apparatus 1 having good responsiveness.

For example, a plurality of variable valve operating devices 1 are provided,
By arranging the control cam 10 of each device 1 on only one shaft, it is possible to simultaneously set the lift amounts of the intake and exhaust valves 3 in the plurality of variable valve operating devices 1 by rotating one shaft. , And a simple configuration.

Although the present invention has been described based on the above embodiments, the present invention is not limited to the above embodiments but includes various embodiments according to the principle of the present invention.

[0053]

According to the first aspect of the present invention, the amount of working fluid in the first pressure chamber is controlled by the control means,
The amount of separation of the valve body from the valve seat can be controlled steplessly.

Accordingly, it is possible to provide a variable valve actuation device capable of setting the lift amount of the valve body with respect to the valve seat in a wider range.

According to the invention of claim 2, in addition to the effect of the invention of claim 1, a better mode of the control means is shown.

According to the third aspect of the present invention, in addition to the effect of the second aspect of the present invention, a better mode of communication control between the first pressure chamber and the second pressure chamber is shown.

According to the invention of claim 4, in addition to the effect of the invention of claim 2 or 3, a better mode of the second moving means is shown.

According to the fifth aspect of the invention, in addition to the effects of the second aspect of the invention, the amount of separation of the valve body from the valve seat in a plurality of units can be set simultaneously, and the control form is simplified. It can be.

According to the sixth aspect of the invention, in addition to the effects of the first to fifth aspects of the present invention, it is possible to improve the responsiveness of the variable valve operating device.

Therefore, it is possible to provide a variable valve operating device having good responsiveness.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a variable valve apparatus 1 according to a first embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Variable valve apparatus 2 Housing 3 Intake / exhaust valve 3a Valve seat 3b Valve seat 4 First cylinder body 4a First cylinder hole 5 First piston 6 Lifter 7 Valve drive cam 8 Second cylinder body 8a Second cylinder hole 9 Second Piston 10 Control cam 11 Oil passage valve 12 Reservoir 12c Accumulation chamber 12d Third piston

Claims (6)

[Claims] A first cylinder body having a first cylinder hole and disposed in the housing so as to be able to move forward and backward, and a first cylinder body disposed to be able to move forward and backward in the first cylinder hole, and having a first pressure in front of the first cylinder body. A first piston that forms a chamber; and a first piston body that can contact the first piston and urges the first piston forward to advance the first cylinder body through the working fluid in the first pressure chamber. Controlling the distance between the first piston and the first moving means by controlling the amount of the working fluid introduced into the first pressure chamber. Means, and a valve element that comes into contact with and separates from the valve seat as the first cylinder body moves. 2. The control means includes a second cylinder body having a second cylinder hole, a second cylinder body disposed in the second cylinder hole so as to be able to move forward and backward and forming a second pressure chamber in front of the second cylinder body. 2. The variable valve operating device according to claim 1, further comprising a piston, a second moving means for moving the second piston forward, and a communication passage communicating the first pressure chamber and the second pressure chamber. 3. The communication path, wherein a valve member capable of cutting off communication between the first pressure chamber and the second pressure chamber, and the communication path between the valve seat member and the second pressure chamber. And a pressure accumulating chamber capable of storing the working fluid flowing out of the second pressure chamber with the movement of the second moving means. 4. The apparatus according to claim 2, wherein said second moving means is a cam.
Or the variable valve train according to claim 3. 5. The second moving means is a cam, the first cylinder body, the first piston, the valve seat, the valve body, the second cylinder body, the second piston, the communication passage, and 3. The variable valve apparatus according to claim 2, comprising a plurality of units each having at least the cam, wherein the cam of each of the units is disposed on a single shaft. 6. The variable valve apparatus according to claim 1, wherein a diameter of the first piston is substantially equal to a diameter of the first cylinder hole.