JPH032647Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Technical Field) The present invention relates to an exhaust valve rotator for an engine.

(Prior art) In order to prevent engine exhaust valves from sealing failure or burning due to adhesion of combustion products, the exhaust valves are rotated using the expansion and contraction movement of a valve spring during engine operation. is being carried out.

Figures 1 to 3 show a first conventional example of a ball built-in type, in which a main body 3 is fixed to the upper end of an exhaust valve 2 protruding from a valve seat 1a of an engine head 1, and the main body has an inclined surface 3a in the circumferential direction. A plurality of grooves 3b are formed, into which balls 4 and coil springs 5 are inserted, supported by disc springs 6, and a retainer 8 is disposed between the disc springs 6 and the upper ends of the coiled valve springs 7. Therefore, exhaust valve 2
When the valve spring 7 is lifted, the disc spring 6 is deflected due to a change in the load on the valve spring 7, and the ball 4 rolls in the circumferential direction along the inclined surface 3a, thereby rotating the exhaust valve 2.

4 to 6 show a second conventional example of a built-in coil spring type, in which a main body 13 is fixed to the upper end of an exhaust valve 12 protruding from a valve seat 11a of an engine head 11, and a coil spring is inserted into an annular groove 13a formed in the main body 13. 15 is inserted and supported by a disc spring 16, and a retainer 18 is disposed between the disc spring 16 and the upper end of a coiled valve spring 17. Therefore, during engine operation, the coil spring 15 is collapsed by the disc spring 16 that moves together with the valve spring 17, as shown in FIG. 6, and this collapse causes the exhaust valve 12 to collapse.
rotates.

However, both the first conventional example and the second conventional example have the disadvantage that the mechanism for rotating the exhaust valve is provided at the upper end of the valve spring, which increases the height and makes the structure complicated and expensive. .

(Objective) It is an object of the present invention to provide an inexpensive exhaust valve rotating device that has a simpler structure without increasing the height.

(Embodiment) FIGS. 7 and 8 show a first embodiment of the present invention.
A retainer 23 is fixed to the upper end of the exhaust valve 22 protruding from the valve seat 21a of the engine head 21, and a coil-shaped valve spring 25 is installed between the lower surface of the retainer 23 and the seat 24 fixed to the engine head 21.
2, a large number of protrusions 26a inclined with respect to the axial direction are formed on the outer periphery at regular intervals, and an elastic cylindrical rotator 26 made of nylon, diuracon, rubber, metal, etc. is used as a valve spring. 25 and its lower surface is fixed to the seat 24, and the inner surface of the strands of the valve spring 25 is pressed against the protrusion 26a.

Next, the effect will be explained. During operation of the engine, when the exhaust valve 22 is opened and the exhaust valve 22 is in the farthest position from the valve seat 21a of the engine head 21, the elastic cylindrical rotator 26 forms a large number of slanted protrusions 26a. The lower surface is fixed to the seat 24 within the spring 25, and the rotator 26
The tips of the outer surfaces of the many inclined protrusions 26a are in contact with the inner spring wires of the valve spring 25 to such an extent that almost no contact pressure is applied (at this time, the inner diameter of the valve spring 25 has expanded to its maximum). ).

Since the valve spring 25 is a compression coil spring when the exhaust valve 22 moves to the closed state in which it is in close contact with the engine head 21 as shown in FIG. 7, that is, when the exhaust valve 22 is lifted, Valve seat 21a
Since the valve spring 25 is lifted and expanded, the inner diameter of the valve spring 25 is reduced as the valve spring 25 is expanded.

At this time, the inner surface of the wire of the valve spring 25 and the rotator 2
The contact pressure with the outer surface of the tip of the protrusion 6 increases as the inner diameter decreases due to the expansion of the valve spring 25. Furthermore, the winding direction of the wire of the valve spring 25 is the same as the direction of inclination of the protrusion 26a of the rotator 26, and the lower surface of the rotator 26 is fixed to the seat 24 fixed to the cylinder head 21. A reaction force of contact pressure is generated according to the winding direction of the wire, acts in a direction to rotate the valve spring 25, and rotates the retainer 23.
Since the exhaust valve 22 rotates together, the exhaust valve 22 also rotates together.

FIG. 9 26' shows a second embodiment of the rotator, in which a number of protrusions 26a' are formed adjacent to each other. The operation is similar to that of the first embodiment.

(Effects) According to the present invention, a retainer is fixed to the upper end of the exhaust valve that protrudes from the valve seat of the engine head, and a coiled valve spring is interposed between the retainer and the engine head with the exhaust valve at the center, and A cylindrical rotator with a large number of protrusions on its outer circumference that is inclined to the valve spring is disposed inside the valve spring and fixed to the engine head, and the inner surface of the valve spring wire is pressed against the protrusions on the outer surface of the rotator to exhaust air. The mechanism for rotating the valve is placed inside the valve spring, making the height lower than before, and the structure is extremely simple, so it can be manufactured at low cost.

[Brief explanation of the drawing]

Fig. 1 is a cutaway front view of the main part of the first conventional example, Fig. 2 is a bottom view of the main body in Fig. 1, Fig. 3 is a front sectional view explaining the ball part in Fig. 1, and Fig. 4 is a front view of the main part of the second conventional example. 5 is a bottom view of the main body of FIG. 4, FIG. 6 is an explanatory view of the operation of FIG. 4, FIG. 7 is a front sectional view of the first embodiment of the present invention, and FIG. A perspective view of the rotator in Figure 7,
FIG. 9 is a perspective view of a second embodiment of the rotator. 21...Engine head, 21a...Valve seat, 2
2... Exhaust valve, 23... Retainer, 25... Valve spring, 26, 26'... Rotator, 26a, 26
a′...projection.

Claims (1)

[Scope of utility model registration request] A retainer is fixed to the upper end of the exhaust valve that protrudes from the valve seat of the engine head, and a coiled valve spring is interposed between the retainer and the engine head around the exhaust valve, and a large number of coiled valve springs are provided that are inclined with respect to the axial direction. An exhaust valve rotation device for an engine, in which a cylindrical rotator having a protrusion formed on its outer periphery is disposed within a valve spring and fixed to an engine head, and the inner surface of the valve spring wire is pressed against the protrusion on the outer surface of the rotator.