JPH08135412A - Valve forced opening and closing mechanism - Google Patents

Abstract

PURPOSE: To provide a mechanism to facilitate processing, installation and removal by constituting a mechanism to rotate a camshaft on which three pieces of cams are formed in a cylindrical lifter and to open and close a valve by way of vertically moving the lifter. CONSTITUTION: A camshaft on an outer peripheral surface of which three pieces of cams 1-3 are formed is installed so as to rotate around the center of a shaft 4 as its axis, and a lifter 2 constrained free to move only in the vertical direction is moved vertically by its rotation. At this time, a valve 10 is opened at the time when the first cam 1 collides and makes contact with the lifter 2, and the valve 10 is closed at the time when the second cam 2 collides and makes contact with it. Additionally, opening and closing of the valve 10 is assisted as the third cam 3 collides and makes contact with it. At the time of making the cams, head end positions of the second and third cams 2, 3 are found so that the valve 10 comes to be in a state of lowering by 5 in the case when a diameter of a base circle of the camshaft is set at 30 and cam lift of each of the cams 1-3 is set at 10.

Description

Detailed Description of the Invention

[0001]

[Industrial application] Mainly used for opening and closing valves of 4-cycle engines.

[0002]

[Prior art]

(A) The conventional valve opening and closing was performed by a cam and a strong spring, and therefore, the strong spring causes a great resistance to rotate the camshaft. (B) In the conventional valve opening and closing, the cam opened the valve and closed the valve with the spring. Therefore, when the rotation was increased, the valve jumped or bounced and the valve did not move in the shape of the cam. . (C) Desmodromic valves, which forcibly open and close conventional valves, required multiple camshafts and rocker arms, so they were bulky and heavy.

[0003]

[Problems to be Solved by the Invention]

(B) This valve opening / closing mechanism eliminates jumps and bounces, which were the problems of valve opening / closing that used conventional springs. (B) This valve opening / closing mechanism does not take up much space and is lighter in weight than conventional desmodromic valves, and solves the problem of valve opening / closing that uses a spring.

[0004]

[Means for Solving the Problem] The inner circle in FIG. 7 is the point O in FIG.
It corresponds to a circle with a radius of 25 centered on. The coordinates (2
5,0) to (25,10), (-25,0) to (-
25, 10) and the protruding portion in FIG. Then, the lifter (part 2) is separately prepared for each of the upper and lower halves and fastened with the screws (11).

[0005]

[Operation] By doing this, processing becomes easier and mounting,
Easy to remove.

[0006]

【Example】

(A) As shown in FIG. 13, attach the cam shaft (part 1) so that it can rotate about the center of the shaft (4),
The lifter (part 2) is rotated about the center of the shaft (4) so as not to move in any direction other than the vertical direction. However,
The rotation direction is counterclockwise in this description. (B) Since the structure must have a clearance so that the metal part can be thermally expanded even if it is thermally expanded, there is not much adhesion with the valve seat (9) when the valve (10) is closed. It is better to have a weak valve spring (8). (C) Shape of the first cam (1) (cam lift, operating angle, etc.)
By changing the engine characteristics according to the characteristics
Since the movement of the cam (2) and the third cam (3) also changes, the lines of the depressions (5) and (6) on the upper left and right of the inner circle in FIG. 6 and the second cam (2) and the third cam () It is necessary to change the shape of.

[0007]

【The invention's effect】

(B) By using this valve opening / closing mechanism, it is possible to overcome many drawbacks of the conventional valve opening / closing. (B) It is especially effective for a racing engine that rotates 10,000 rpm or more.

[Brief description of drawings]

1 is a perspective view of a component 1 of the present invention.

FIG. 2 is a front view of the component 1 of the present invention.

FIG. 3 is a right side view of the component 1 of the present invention.

FIG. 4 is a perspective view of component 2 of the present invention.

FIG. 5 is a front view of component 2 of the present invention.

FIG. 6 is a side view of the component 2 of the present invention.

7 is a sectional view taken along line b of FIG. The recesses (5) and (6) on the left and right of the upper part of the inner circle serve as the passage of the second cam (2) and the passage of the third cam (3) on the right when the valve (10) is open. For the calculation method of the dent line, see FIG. 12 and the description of FIG.

FIG. 8 is a sectional view taken along line e of FIG.

FIG. 9 is a perspective view of a combination of the component 1 and the component 2 of the present invention.

FIG. 10 is a front view of a combination of the component 1 and the component 2 of the present invention.

FIG. 11 is a side view of a combination of the component 1 and the component 2 of the present invention.

FIG. 12 is a recess (5) on the upper left and right of the inner circle of FIG.
It is a figure explaining the calculation method of (6). * Calculation method The diameter of the base circle of the camshaft is 30, and the cam lift of the first cam (1), the second cam (2) and the third cam (3) is 1.
In the case of 0: Find the positions of the tips of the second cam (2) and the third cam (3) when the valve (10) is in the state of being lowered by 5. First, the shaft (4) when the valve (10) is closed
The point at the center of is defined as O (0,0). A circle centered on this point O and having a radius of 25 corresponds to the inner circle in FIG. And the fact that the valve (10) went down by 5 means that the shaft (4)
Can be considered in the same way as when the point 5 has risen by 5, so that the center of the shaft (4) comes from the point O to the point O ′ (0,5) on the point 5 and then the radius of 25 around the point O ′. Draw a circle,
The two points P and P'where the circle and the straight line Y = -15 intersect are determined, and the two points P and P'are set as the tip of the first cam (1), and the coordinates of the points O'P and P'are determined. The coordinates of the tip of the second cam (2) and the third cam (3) are obtained. Thus, the Y of the point O '
The coordinates are moved from 0 to 10 and the same calculation is performed to find the lines of the depressions (5) and (6) on the upper left and right of the inner circle in FIG.

FIG. 13 is a front view of the embodiment of the present invention.

[Explanation of symbols]

1 1st cam 2 2nd cam 3 3rd cam 4
Shaft 5 Left dent 6 Right dent 7 Valve mounting screw hole 8 Valve spring 9 Valve seat 10
Valve 11 Screw (2nd cam of 3 and 3rd cam of 3
The left depression of 6 and the right depression of 6 are symmetrical with respect to the Y axis (see FIG. 12). )

Claims (1)

[Claims] (A) A cam shaft (part 1) having three cams of first, second, third is rotated in a tubular lifter (part 2) to move the lifter up and down. (B) The first cam (1) opens the valve, the second cam (2) closes the valve, and the third cam (3) is combined to make the valve the shape of the first cam (1) by three cams. Assist in how to move.