JPH11236809A - Variable valve device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a variable valve device with secured stable operations. SOLUTION: A variable valve device is composed of a suction/exhaust valve 2; a first plunger 4 which is installed in the first cylinder hole 3a in a cylinder body 3 to form a pressure chamber 13 and is driven by a first eccentric drive cam 8; a second plunger 5 which is energized by a working oil pressurized by the first plunger 4 and operates the valve 2; a piston 6 installed in the second cylinder hole 3b in the cylinder body 3 to form a pressure absorption chamber 14; a third plunger 7 which variably sets the initial position of the piston 6; and a second eccentric drive can 9. The cylinder body 3 is furnished with a supply port 3d to supply the working oil and a plug 16, and the pressure chamber 13 and pressure absorption chamber 14 are closed tightly by blocking the supply port 3d with the plug 16.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable valve apparatus for variably controlling a valve lift or opening / closing valve timing.

[0002]

2. Description of the Related Art A conventional variable valve apparatus is disclosed in
As disclosed in Japanese Patent Application Publication No. 189633, a valve and a first cylinder hole provided in the cylinder body are disposed so as to be able to advance and retreat, and a pressure chamber is formed in front thereof.
A first plunger which pressurizes hydraulic oil in the pressure chamber by being driven by a driving means, and which is disposed in the first cylinder hole so as to be able to move forward and backward and forms the pressure chamber behind the first plunger; A second plunger actuated by the hydraulic oil pressurized by the first plunger to operate the valve, and a second cylinder hole provided in the cylinder body, which is disposed so as to be able to advance and retreat, A variable valve comprising: a piston forming a pressure absorbing chamber forwardly into which hydraulic oil pressurized by the first plunger can flow, and variable piston position setting means for variably setting an initial position of the piston. In the device, the piston position changing means urges the piston backward by causing lubricating oil of an internal combustion engine to flow into the pressure absorption chamber via the pressure chamber. There is known, which comprises causing to act on so that.

[0003]

However, this conventional variable valve apparatus uses lubricating oil for an internal combustion engine. Generally, the lubricating oil for an internal combustion engine has a high viscosity when it is cold and has a high viscosity when it is hot. Due to the lowering characteristic, there is a possibility that the operation of the variable valve apparatus differs depending on the temperature condition.

[0004] It is an object of the present invention to provide a variable valve device that ensures stable operation.

[0005]

In order to solve the above-mentioned problems, a valve and a first cylinder hole provided in a cylinder body are provided so as to be able to move forward and backward, and a pressure chamber is formed in front of the valve. A first plunger that pressurizes the working fluid in the pressure chamber by being driven by driving means;
The first cylinder hole is provided so as to be able to move forward and backward, and the pressure chamber is formed behind the first cylinder hole, and the valve is operated by being urged by the working fluid pressurized by the first plunger. Two plungers and a second cylinder hole provided in the cylinder body are provided so as to be able to move forward and backward, and form a pressure absorbing chamber in front of which a working fluid pressurized by the first plunger can flow. In a variable valve actuating apparatus comprising a piston and a piston position variable setting means for variably setting an initial position of the piston, the cylinder body supplies a working fluid to the pressure chamber and the pressure absorption chamber. And a closing member for closing the supply port, wherein the pressure chamber and the pressure absorption chamber are hermetically sealed by closing the supply port with the closing member. It was constructed with a variable valve controlling system according to claim.

Preferably, the piston position variable setting means is disposed in the second cylinder hole so as to be able to advance and retreat behind the piston, and is advanced and retreat by auxiliary driving means, and has a front portion of the piston. It is desirable that the variable valve actuating device be provided with a third plunger that defines a retreat limit of the piston by contacting the rear portion.

According to a first aspect of the present invention, the supply port is closed by a closing member. In the second aspect of the invention, in addition to the operation of the first aspect, the third plunger is advanced and retracted by the auxiliary driving means. , The retraction limit of the piston is defined.

[0008]

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 an intake / exhaust valve 2, a cylinder body 3, a first plunger 4, a second plunger 5, a piston 6, a third plunger 7, a first eccentric drive cam 8, It has an eccentric drive cam 9 and a plug 16.

The cylinder head 10 is provided with a valve seat 2a for the intake / exhaust valve 2. The valve seat 2a is a cylinder head 1
0 communicates with the gas passage 11.

The valve body 2b of the intake / exhaust valve 2 is disposed on the cylinder head 10 so as to be able to reciprocate in its axial direction (vertical direction in FIG. 1). The valve body 2b is constantly urged by the valve spring 12 in the closing direction of the intake / exhaust valve 2, that is, upward in FIG.

Above the cylinder head 10, a cylinder body 3 is provided. The cylinder body 3 has a first cylinder hole 3a extending coaxially with the axis of the valve body 2b in the vertical direction in FIG. 1, and a left and right side in FIG. 1 such that the axis of the first cylinder hole 3a is perpendicular to the axis. A second cylinder hole 3b extending in the direction is formed.

A first plunger 4 is disposed in an upper portion of the first cylinder hole 3a so as to be able to move up and down in FIG. 1, and a second plunger 5 is provided in a lower portion of the first cylinder hole 3a. Are disposed so as to be able to move up and down in FIG. In the first cylinder hole 3a, a pressure chamber 13 is formed between an end face on the front side (lower side in FIG. 1) of the first plunger 4 and an end face on the rear side (upper side in FIG. 1) of the second plunger 5. Have been.

A piston 6 is disposed in the second cylinder hole 3b so as to be able to move forward and backward in the left-right direction in FIG. A pressure absorbing chamber 14 is formed between a front end surface (left side in FIG. 1) of the piston 6 and a bottom surface of the second cylinder hole 3b facing the front end surface of the piston 6. Pressure chamber 1
3 and the pressure absorbing chamber 14 are communicated via a communication passage 3c formed in the cylinder body 3.

A first eccentric drive cam 8 is disposed above the cylinder body 3 so as to abut on the rear end surface of the first plunger 4 on its outer peripheral surface. First eccentric drive cam 8
Are rotated in synchronization with the crankshaft of an internal combustion engine (not shown), and the first eccentric drive cam 8 is rotated, whereby the first
The plunger 4 is moved in the first cylinder 3a.

A third plunger 7 is disposed rearward of the piston 6 in the second cylinder hole 3b so as to be able to advance and retreat in the large two cylinder hole 3b. A lift adjustment chamber 15 is formed between the front end face 7 and the front end face.

In the lift adjusting chamber 15, the piston 6 and the third
A spring 16 is provided between the plunger 7. The spring 16 moves the piston 6 forward, i.e.
It is constantly biased to the middle left.

A second eccentric drive cam 9 which is in contact with the rear end surface of the third plunger 7 on its outer peripheral surface is disposed on the side of the cylinder body. The rotation of the second eccentric drive cam 9 moves the third plunger 7 through the second cylinder hole 3b.

The cylinder body 3 has a supply port 3d for communicating the pressure absorbing chamber 14 with the outside of the cylinder body 3. When the hydraulic oil flows into the cylinder body 3 from the supply port 3d, a predetermined amount of the hydraulic oil is filled into the pressure absorbing chamber 14, the communication path 3c, and the pressure chamber 13.

After filling the pressure chamber 13, the communication passage 3c, and the pressure supply chamber 14 with hydraulic oil, a plug 16 is fitted into the supply port 3d. By mounting the plug 16 to the cylinder body 3, the pressure chamber 3, the communication passage 3c, and the pressure supply chamber 1
Reference numeral 4 denotes a sealed state.

Next, the operation of the variable valve operating device 1 will be described. In the initial state shown in FIG.
a, so that the intake / exhaust valve 2 takes a closed state,
The communication between the gas passage 11 and the outside of the cylinder head 10 is shut off. The urging force of the valve spring 12 is set to be larger than the urging force of the spring 16.

When the first eccentric drive cam 8 is rotated, for example, clockwise in FIG. 1, the first plunger 4 is moved forward (downward in FIG. 1) in the first cylinder hole 3a. The hydraulic oil in the pressure chamber 13 is pressurized by the advance of the first plunger 4,
The working oil flows into the pressure supply chamber 14 via the communication passage 3c.

When the hydraulic oil flows from the pressure chamber 13 into the pressure absorbing chamber 14, the piston 6 is moved backward against the spring 16, that is, in the direction in which the pressure absorbing chamber 14 expands. When the piston 6 is retracted, the piston 6 is moved to the third plunger 7.
It is continued until it contacts.

When the piston 6 comes into contact with the third plunger 7 and its retreat is regulated by the third plunger 7, the hydraulic oil cannot flow from the pressure chamber 13 into the pressure absorbing chamber 14. Therefore, the pressure chamber 13 pressurized by the first plunger 4
The hydraulic oil inside presses and urges the second plunger 5 forward (downward in FIG. 1), and the second plunger 5 is moved forward in the first cylinder hole 3a.

When the second plunger 5 advances, the valve body 2b
Is pressed against the valve spring 12 in the opening direction of the intake / exhaust valve 2 (downward in FIG. 1). Therefore, the movement of the valve body 2b causes the valve body 2b to be separated from the valve seat 2a, and the intake / exhaust valve 2
Is opened, and the gas passage 11 communicates with the outside of the cylinder head 10.

That is, by the action of the pressure absorbing chamber 14, the first
The timing of starting the movement of the valve body 2b in the opening direction of the intake / exhaust valve 2 is later than the timing of starting the forward movement of the plunger 4, in other words, the first timing.
The opening timing of the intake / exhaust valve 2 is later than the start of the lift of the eccentric drive cam 8. The amount of delay in opening the intake and exhaust valves 2 is determined by the amount of hydraulic oil that can flow into the pressure absorption chamber 14.

When the first eccentric drive cam 8 continues to rotate and its vertex contacts the rear end face of the first plunger 4, the amount of separation of the valve body 2b from the valve seat 2a becomes maximum. When the apex portion of the first eccentric drive cam 8 passes through the rear end face of the first plunger 4, the valve body 2b is urged upward in FIG.

When the valve body 2b moves in the closing direction (upward in FIG. 1) of the intake / exhaust valve 2 with respect to the cylinder head 10, the second plunger 5 and the first plunger 4 move backward in the first cylinder hole 3a. (Upward in FIG. 1), and the valve body 2
b contacts the valve seat 2a, the intake / exhaust valve 2 is closed, and the gas passage 11 is shut off from the outside of the cylinder head 10.
After the valve body 2b comes into contact with the valve seat 2a, the retreating movement of the second plunger 5 also ends with the end of the movement of the valve body 2b in the closing direction of the intake / exhaust valve 2, and the piston 6 is moved forward by the spring 16. Moved to

When the piston 6 advances, the pressure absorbing chamber 14
The working oil in the inside flows into the pressure chamber 13. When the hydraulic oil flows from the pressure absorbing chamber 14 into the pressure chamber 13, the first plunger 4 is further urged rearward, and eventually the first plunger 4, the second plunger 5, and the piston 6
Returns to the initial state.

When the second eccentric drive cam 9 is rotated by a predetermined amount, for example, clockwise in FIG. 1, by a step motor (not shown) controlled by an electronic control unit (not shown) for controlling the engine, the third plunger 7 is rotated. Second cylinder hole 3b
Is moved forward (to the left in FIG. 1). As the third plunger 7 moves forward, the retreat limit position of the piston 6 is moved forward in the second cylinder hole 3b.

When the third plunger 7 advances, the piston 6 generated by the inflow of hydraulic oil from the pressure chamber 13 to the pressure absorbing chamber 14 as the first plunger 4 advances.
Is reduced. That is, the delay of the movement start timing of the valve body 2b in the opening direction of the intake / exhaust valve 2 with respect to the advance start timing of the first plunger 4 is different from the advance start timing of the first plunger 4 in the operation in the initial state shown in FIG. Valve body 2b
Is shorter than the delay of the start timing of the movement of the intake / exhaust valve 2 in the opening direction.

Further, since the amount of hydraulic oil flowing from the pressure chamber 13 into the pressure absorbing chamber 14 with the advance of the first plunger 4 is reduced, the amount of advance of the second plunger 5 and the valve seat 2a of the valve body 2b are reduced. Will be increased.

Therefore, by appropriately selecting the position of the third plunger 7 in the second cylinder 3b, the lift amount and the opening / closing timing of the intake / exhaust valve 2 can be set.

As described above, the variable valve apparatus 1 according to the present embodiment has a configuration in which the pressure chamber 13 and the pressure absorption chamber 14 are hermetically closed. Hydraulic oil to be filled in the air intake / exhaust valve 2 can be selected as appropriate for the lift amount and opening / closing timing setting mechanism of the intake / exhaust valve 2, thereby enabling stable control of the intake / exhaust valve 2.

Therefore, it is possible to provide the variable valve operating device 1 that ensures stable operation.

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.

[0037]

According to the first aspect of the present invention, since the pressure chamber and the pressure absorbing chamber are configured to be hermetically sealed, the working fluid filled in the pressure chamber and the pressure absorbing chamber can be lifted by the valve. And a mechanism suitable for the opening / closing timing setting mechanism, thereby enabling stable valve control.

Therefore, it is possible to provide a variable valve operating device that ensures stable operation.

According to the invention of claim 2, in addition to the effect of the invention of claim 1, a better form of the piston position variable setting means is shown.

[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 Intake / exhaust valve 3 Cylinder body 3a 1st cylinder hole 3b 2nd cylinder hole 3c Communication passage 3d Supply port 4 1st plunger 5 2nd plunger 6 Piston 7 3rd plunger 8 1st eccentric drive cam 9th 2 Eccentric drive cam 13 Pressure chamber 14 Pressure absorption chamber 16 Plug

Claims (2)

[Claims] And a pressure chamber formed in a first cylinder hole provided in the cylinder body so as to be able to move forward and backward, and formed with a pressure chamber in front of the valve. A first plunger for pressurizing the working fluid therein; a first plunger disposed in the first cylinder hole so as to be able to move forward and backward; and a pressure chamber formed behind the first plunger, and the working fluid pressurized by the first plunger. A second plunger for actuating the valve by being urged, a second plunger disposed in the cylinder body being disposed so as to be able to move forward and backward, and being pressurized forward by the first plunger. A variable valve train, comprising: a piston forming a pressure absorption chamber into which a working fluid can flow; and a piston position variable setting unit variably setting an initial position of the piston. The cylinder body includes a supply port that supplies a working fluid to the pressure chamber and the pressure absorption chamber, and a closing member that closes the supply port, and the supply port is closed by the closing member. The pressure chamber and the pressure absorption chamber are hermetically closed by a valve. 2. The variable piston position setting means is disposed in the second cylinder hole so as to be able to advance and retreat behind the piston, and is advanced and retracted by an auxiliary driving means, and a front part thereof is a rear part of the piston. 2. The variable valve operating device according to claim 1, further comprising a third plunger that defines a retreat limit of the piston by contacting the piston.