JPH062519A - Engine valve gear - Google Patents

Abstract

(57) [Summary] [Object] The present invention aims to perform valve body control without adding inertial weight to a valve train. A low-speed rocker arm that engages with a low-speed cam and a high-speed rocker arm that engages with a high-speed cam are joined at one end by a pin, and a valve element is engaged with this one end. On the other hand, a lash adjuster is arranged at the other end of each rocker arm to act as a fulcrum of each rocker arm.
Further, the high speed lash adjuster is provided with a deenergizing means for deactivating its rigidity.

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 engine, and is used, for example, to make the lift of intake and exhaust valves of an engine variable.

[0002]

2. Description of the Related Art As a prior art relating to the present invention, there is a "valve device for an internal combustion engine" disclosed in Japanese Patent Application Laid-Open No. 2-78720. This conventional technique will be described with reference to FIG. 4. The rocker arms 71, 72, 73 are swingably arranged around a rocker shaft 74. here,
The rocker arms 71 and 73 are engaged with the respective valve bodies (not shown), and the rocker arm 71 has a low speed cam (not shown) which is not shown and the rocker arm 72 has a high speed cam (not shown) which is not shown. Are engaged with perfect circular cams (projection amount 0). Here, the two valve bodies act as two intake valves (or exhaust valves) arranged in one cylinder. Rocker arms 71, 72, 7
3, continuous cylinders 75, 76, 77 are formed,
Pistons 78, 79, 80 divided into three parts are slidably inserted therein. Further, a pressure chamber 81 is formed by the cylinder 75 and the piston 78, and a spring 84 is arranged in the pressure chamber 81 and the rocker shaft 7
The oil pressure is supplied from the oil supply passage 82 formed in the engine 4 through the oil passage 83 formed in the rocker arm 71. On the other hand, a spring chamber 85 is formed by the cylinder 77 and the piston 80, and a spring 86 arranged inside thereof urges the pistons 78, 79, 80 upward in the drawing.

In this "valve system for internal combustion engine", the state shown in FIG. 4 is when the internal combustion engine has a low load, the amount of hydraulic pressure supplied to the pressure chamber 81 is small, and each piston 78, 79, 80 has a spring 86. The contacting surfaces are in sliding contact with each other at the positions shown in the figure by the urging force of. Therefore, the rocker arm 71 swings only by the low speed cam, the rocker arm 72 swings only by the high speed cam, and the rocker arm 73 does not swing because it engages with the perfect circular cam. As a result, the rocker arm 71
Only the valve element that engages with opens and closes with a small stroke. That is, only one intake valve is opened / closed in one cylinder.

On the other hand, when the internal combustion engine is under heavy load, the amount of hydraulic pressure supplied to the pressure chamber 81 is increased so that the pistons 78, 79,
80 moves downward in the drawing against the biasing force of the spring 86. As a result, the piston 75 moves to the rocker arm 71,
The rocker arms 71, 72, 73 are integrally connected by the pistons 75, 76 because the pistons 76 are positioned so as to connect the rocker arms 72, 73 with each other. At this time, the high-speed cam causes the rocker arm 7 to move more than the low-speed cam swings the rocker arm 71.
Since the amount of rocking 2 is larger, the integrated rocker arms 71, 72, 73 rock according to the profile of the high speed cam. Therefore, both the valve bodies engaging with the rocker arms 71 and 73 open and close with a large stroke. That is,
There are two intake valves opened and closed in one cylinder. As a result, a larger amount of air can be taken into the combustion chamber (not shown) than when the internal combustion engine has a low load.

[0005]

However, in the "valve device for an internal combustion engine" as described above, since the piston, the spring and the like are arranged on the rocker arm, the inertial weight of the valve operating system increases and the opening and closing of the valve body is increased. It is disadvantageous in responsiveness. Other conventional techniques include, for example, those disclosed in Japanese Patent Laid-Open No. 2-267307 and those disclosed in Japanese Patent Laid-Open No. 4-116211.

In view of this, the present invention has as its technical subject to perform valve body control without adding inertial weight to the valve train.

[0007]

[Constitution of the invention]

[0008]

Means for Solving the Problems The technical means of the present invention taken to solve the above-mentioned technical problems of the present invention include a valve body and a plurality of valve bodies, one end of which is connected to the valve body. Rocker arm and rocker arm swing,
First and second cams having different cam profiles, a plurality of lash adjusters that engage with the other ends of the plurality of rocker arms, and a deactivating means that deactivates the rigidity of the lash adjusters that engage with the first cam. That is, the valve operating device for the engine is configured.

[0009]

According to the above-mentioned technical means of the present invention, when the deactivating means deactivates the rigidity of the lash adjuster which engages with the first cam, the valve body passes through the lash adjuster which is swung by the second cam. Is driven to open and close. Further, when the depressing means does not depress the rigidity of the lash adjuster engaged with the first cam, the valve element is opened and closed via the lash adjuster swung by the first cam.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments embodying the technical means of the present invention will be described below with reference to the accompanying drawings.

1 to 3, in one cylinder having an engine 11, two intake passages (or exhaust passages: only one side is shown in FIG. 1) 12 have two valve bodies (intake valves or exhaust valves) 13, A valve seat 14 (a valve seat for the valve element 14 is not shown in FIG. 1) is disposed so as to be separable from and in contact with the valve seat 15. One end of the rocker arm 16 is engaged with the upper end of the valve body 13 in the drawing,
One end of a rocker arm 17 is engaged with the upper end of the valve body 14 in the figure. A rocker arm 18 is located between the rocker arms 16 and 17, and these three members are connected at one end thereof via a pin 19. Therefore, the valve body 1
3 and 14 are engaged with all of the rocker arms 16, 17, and 18.

The rocker arms 16, 17, and 18 have lash adjusters 20, 21, and 22 as fulcrums, respectively.
The cam profile of the cams 23, 24, 25 swings. Here, the cams 23 and 24 are low speed cams (second cams), and the cam 25 is a high speed cam. The rocking amount of the rocker arm 18 by the cam 25 is larger than the rocking amount of the rocker arm 16, 17 by the cams 23, 24. In addition, the rocker arms 16, 17, 18 and the cam 2
Rollers 26, 27, 28 are provided at the contact portions with 3, 24, 25.
The cams 16, 17, 18 are driven by an output shaft (not shown) of the engine 11 via a cam shaft 29.

A spring 31 is provided between the main body of the engine 11 and a cotter 30 fixed to the valve body 13 (a cotter for the valve body 14 is not shown in FIG. 1), so that the valve body 13 is seated in the valve seat 15. It is biased in the direction to be seated on.

The lash adjusters 20, 21, 22 will be described with reference to FIG. 4. The cylinder 32 embedded in the main body of the engine 11 has a bottomed cylindrical shape, and the first and second pistons 33, 34 are provided inside the cylinder 32. Slide. One end of the first piston 33 acts as a fulcrum of the rocker arms 16, 17, 18 and the other end is cup-shaped, and the second piston 3
4 and the reservoir chamber 35 is formed. The inside of the second piston 34 is divided into two spaces by a partition wall 36, the upper side in the figure serves as the aforementioned reservoir chamber 35, and the lower side in the figure constitutes a pressure chamber 37 together with the bottom part of the cylinder 32. A check valve 38 is arranged in the pressure chamber 37, and opens and closes a communication hole 39 formed in the partition wall 36. A third piston 41 having a pin portion 40 is arranged inside the reservoir chamber 35 to divide the inside of the reservoir chamber 35 into chambers 42 and 43. The pin portion 40 is located in the chamber 43 and can press the check valve 38. Further, a spring 44 is arranged in the chamber 43, and the pin portion 40 of the third piston 41 is attached to the check valve 3
It is urged away from 8.

An oil supply passage 45 and an oil discharge passage 46 are formed in the main body of the engine 11, the oil supply passage 45 communicates with an oil pressure source (not shown), and the oil discharge passage communicates with an oil pan (not shown). A control valve 47 that opens and closes the oil discharge passage 46 is provided. The oil supply passage 45 communicates with the chamber 42 of the reservoir chamber 35 via an oil passage 48 formed in the cylinder 32 and an oil passage 49 formed in the first piston 33, and the reservoir chamber 35 is always hydraulically operated. Source oil pressure is supplied. Further, a constant hydraulic pressure is also stored in the pressure chamber 37. On the other hand, the oil discharge passage 46 communicates with the chamber 43 of the reservoir chamber 35 via the oil passage 50 formed in the cylinder 32 and the oil passage 51 formed in the second piston 34.

Although the deactivating means is composed of the third piston 41, the oil discharge passage 46 and the control valve 47, the lash adjuster 2 is engaged with the cams 23 and 24 which are low speed cams.
No deactivating means may be provided at 0 and 21.

The operation of the valve operating system for the engine having the above construction will be described. The cam shaft 29 and the cams 23, 24, 25 rotate as the engine 11 starts. Now, when the engine 11 has a low load, the deactivating means acts on the lash adjuster 22. That is,
In the lash adjuster 22, the control means (not shown) that detects that the engine 11 has a low load opens the control valve 47 and connects the chamber 43 of the reservoir chamber 35 to the oil pan via the oil discharge passage 46. As a result, the hydraulic pressure supplied to the chamber 42 causes the third piston 41 to move downward in the drawing against the urging force of the spring 44, and the pin portion 40 opens the check valve 38. Therefore, since the hydraulic pressure in the pressure chamber 37 escapes from the chamber 43, the first and second pistons 33, 34 move up and down in the cylinder 32. On the other hand, this action does not occur in the lash adjusters 20 and 21. Therefore,
When the engine 11 has a low load, the lash adjuster 2
Although 0 and 21 have rigidity and serve as a fulcrum of the rocker arms 16 and 17, the lash adjuster 22 cannot be used as a fulcrum of the rocker arm 18 due to the depressurization of rigidity, and the rocker arm 18 swings around the pin 19 as a fulcrum. Therefore, only rocking of the rocker arms 16 and 17 acts on the valve bodies 13 and 14, and the valve bodies 13 and 14 are driven to open and close based on the cam profiles of the cams 23 and 24 which are low speed cams. Since the lift amount of the valve bodies 13, 14 by the cams 23, 24 is relatively small, the amount of air supplied from the intake passage 12 to the combustion chamber (not shown) is relatively small.

On the other hand, when the engine 11 has a high load, the deenergizing means does not work at all. As a result, engine 1
The check valve 38 of the lash adjuster 22 opened by the pin portion 40 at the time of low load of 1 does not open at the time of high load of the engine 11, and the lash adjusters 20, 21, 22 all maintain rigidity. Therefore, the rocker arms 16, 1
7 swings around the lash adjusters 20 and 21, and the rocker arm 18 moves toward the lash adjuster 22.
It swings about. At this time, the amount by which the cam 25, which is a high speed cam, swings the rocker arm 18 is larger than the cam 2
3 and 24 are larger than the rocker arms 16 and 17 rocking, and the rocker arms 16, 17 and 18 are integrated by the pin 19, so that the rockers arm 18 rocks on the valve bodies 13 and 14. The valve bodies 13 and 14 are opened and closed based on the cam profile of the cam 25. Since the lift amount of the valve bodies 13 and 14 by the cam 25 is relatively large, the amount of air supplied from the intake passage 12 to the combustion chamber (not shown) is relatively large.

[0019]

As described above, in the valve operating system for an engine of the present invention, when the lift amount of the valve element is changed, no additional weight is added to the cam, rocker arm and valve element, that is, no inertial weight is added, so that the cam is not added. Excellent driving response of rocker arm and valve body.

[Brief description of drawings]

FIG. 1 is a cross-sectional view (cross-section taken along the line AA in FIG. 2) of a valve operating system for an engine according to an embodiment of the present invention.

FIG. 2 shows a B view in FIG.

FIG. 3 shows a view from C in FIG.

FIG. 4 shows a cross-sectional view of a main part in FIG.

FIG. 5 is a cross-sectional view of a main part of a conventional valve operating system for an internal combustion engine.

[Explanation of symbols]

 13, 14 valve body, 16, 17, 18 rocker arm, 20, 21, 22 lash adjuster, 23, 24 first cam, 25 second cam,

Claims (1)

[Claims] 1. A valve body, a plurality of rocker arms, one end of which is connected to engage with the valve body, and first and second cams that swing the plurality of rocker arms and have different cam profiles. A valve operating device for an engine, comprising: a plurality of lash adjusters that are respectively engaged with the other ends of the plurality of rocker arms; and deactivating means that deactivates the rigidity of the lash adjusters that engage with the first cam.