Valve spring retainer for internal combustion engine

Field of invention

The present invention relates to "Valve spring retainer for internal combustion engine" and more particularly to a valve spring retainer for valve operating mechanism for

Internal combustion engines.

Brief description of the invention

An intimae combustion engine includes at least one reciprocating piston disposed in a combustion chamber for in taking fresh and exhausting burnt fuel via a network of poppet valves. A poppet valve is slide ably supported in a cylinder head and disposed in a seated position in a valve seat. The poppet valve includes a valve head adapted to seal against the valve seat and an elongated cylindrical stem extending perpendicularly from the valve head and slide ably supported in a valve guide for perpendicular movement toward and away from the seating position at the valve seat.

The stem guide is fixedly disposed in a portion of the cylinder head in a manner well known in the art. A return spring the helical wound compression type surrounds an upper portion of the stem above the stem guide for urging the poppet valve in a predetermined direction toward the seating position. The bottom end of the return spring rests against a support portion of the cylinder head adjacent the valve guide and an upper portion of the rectum spring engages a retainer means, for transferring forces to the poppet valve. That is, the retainer means is fixedly disposed on, or attached to, the end of the stem distal the valve head for retaining the return spring on the poppet valve. Thus, the retainer means moves with the poppet valve and functions to interconnect the stem of the poppet valve and the return spring. The retainer means has an operational position on the stem, wherein the retainer means is adapted to retain the return spring upon the stem and transfer forces there between. That is to say, the operational position is a predetermined relative position between the retainer mean and the stem in which the return spring is retained on the poppet valve ready for operation in the engine.

In prior art, poppet valve assemblies for compact engines; two collinear, inner and outer springs are used to achieve required pre load and working load for valve movement.

Achieving lower square ness values for the spring outer and spring inner in mass production requires special effort and cost.

Due to the space restriction and higher square ness values of springs, it is observed that the springs touch each other and makes noise. To reduce such adverse effects, single spring design is provided to meet required loading within space. In such compact engines (Ratio of Spring Installed length to spring mean coil diameter of value 1.2 to 1.4), valve spring retainer developed for single spring design have more weight. As valves for internal combustion engines are repeatedly opened and closed several times per second during the operative cycles of an internal combustion engine, such increased weight has adverse effect on engine performance.

To solve such problems, aluminum alloy valve spring retainers having reduced weight are also known in the prior art but they are generally too soft and not strong enough to be used for valve spring retainers. Also, they are not economically feasible.

Accordingly, there is a need to provide a retainer for maintaining the valve spring in compression which is having reduced weight, simple in design, and yet, sturdy enough to withstand the adverse operating conditions encountered within an internal combustion engine.

Brief description of the drawings

Figure 1 illustrates an engine along with its parts

Figure 2 illustrates the valve poppet valve arrangement

Figure 3 A illustrates the perspective view of retainer as in the prior art

Figure 3 B illustrates the top view of the retainer in the present invention

Brief description of the invention

It is therefore the object of the invention to provide a valve spring retainer utilized in conjunction with poppet valves in internal combustion engines, particularly valve spring retainer having reduced weight to improve the engine performance.

Accordingly, the present invention relates to a Valve spring retainer having reduced weight. Mass is removed from outer tubular portion. The mass of the retainer is selectively removed starting from the outer periphery of the outer tubular portion to join with the outer diameter of the inner tubular portion to form a shape of segments projecting from inner tubular portion equally distributed in a flower shape.

Further, the valve spring retainer according to the present invention is manufactured in conventional cold forging process.

In another aspect of the present invention, the valve spring retainer according to a first aspect of the invention is done for single spring guiding design.

In still another aspect of the invention, the valve spring retainer design according to a first aspect of the invention can also be done for Seat Valve springs and also for Retainer valve springs with two springs guiding.

Thus, the present invention provides a retainer for maintaining the valve spring in compression which is having reduced weight, simple in design, and yet, sturdy enough to withstand the adverse operating conditions encountered within an internal combustion engine.

Detailed description of the invention

A selected Illustrative embodiment of the present Invention will be now described with respect to the accompanying figures.

Figure 1 illustrates the principal portion of the engine 102 of the present invention is shown in cross-sectional view. As shown in this figure, the engine includes a crankcase 201, a cylinder block 202 connected to the crankcase 201, a cylinder head 203 to be connected to the cylinder block 202 and a cylinder head cover. These are clamped and fixed together via stud bolts and the like, thereby constituting the main structure of the engine 102.

The crankcase has a structure in which the half cases 204 & 205 are integrally connected to each other. The halves cases and are formed by dividing the crankcase into right 205 and left portions 204. In the crankcase, formed of the combined half cases and, a crankshaft is Rota table bearing 206 supported. A connecting rod 207 is Rota table attached to a crankpin of the crankshaft 208 via a bearing located at the large-end thereof. A piston 209 is pivotally attached to the small-end of the connecting rod 207 via a piston pin. In this embodiment, there is provided one piston and the engine of the present invention is a single cylinder 4-cycle engine. in the transmission portion of the power unit, a variable speed ratio V-belt drive 210 extends rearward from about the crankshaft 208.

A driving pulley 211 is fixed to the crankshaft. The driving pulley includes a fixed pulley half 212 which is caused to rotate with the output shaft. The fixed pulley half is disk shaped with a conical pulley surface. On the outer side of the pulley half is a fan 213 to cool the system with air drawn in through a passageway formed in the case 201. To provide lubrication to the engine assembly 102, which must cycle back and forth under load during driving of the vehicle, a sump for lubrication oil is provided.

Figure 2 explains the valve arrangement of the engine 102 according to the scope of the present invention. The engine 102 includes at least one reciprocating piston 209 disposed in a combustion chamber in the cylinder block 202 for in taking fresh and exhausting burnt fuel via a network of poppet valves 301. A poppet valve 301 is slide ably supported in a cylinder head 203 and disposed in a seated position in a valve seat 302. The poppet valve 301 includes a valve head 303 adapted to seal against the valve seat 302 and an elongated cylindrical stem 304 extending perpendicularly from the valve head 303 and slide ably supported in a valve guide for perpendicular movement toward and away from the seating-position at the valve seat 302.

The stem guide is fixedly disposed in a portion of the cylinder head 203 in a manner well known in the art. A return spring 305 of helical wound compression type surrounds an upper portion of the stem 304 above the stem guide for urging the poppet valve 301 in a predetermined direction toward the seating position. The bottom end of the return spring 305 rests against a support portion of the cylinder head 203 adjacent the valve guide and an upper portion of the return spring 305 engages a retainer means 306, for transferring forces to the poppet valve 301. Thus, the retainer means 306 moves with the poppet valve 301 and functions to interconnect the stem of the poppet valve 301 and the return spring 305.

The retainer means 306 has an operational position on the stem 304, wherein the retainer means 306 is adapted to retain the return spring 305 upon the stem 304 and transfer forces there between. That is to say, the operational position is a predetermined relative position between the retainer mean 306 and the stem 304 in which the return spring 306 is retained on the poppet valve 301 ready for operation in the engine.

As valves 301 are repeatedly opened and closed several times per second during the operative cycles of an internal combustion engine 102, such increased weight has adverse effect on engine performance.

Accordingly, the present invention Figure 3B relates to a Valve spring retainer having reduced weight when compared to it in the prior art that can be observed from Figure 3A. Mass is removed from outer tubular portion 307. The mass of the retainer 306 is selectively removed starting from the outer periphery of the outer tubular portion 307 to join with the outer diameter of the inner tubular portion 308 to form a shape of segments 309 projecting from inner tubular portion 308 equally distributed in a flower shape.
Further, the valve spring retainer 306 according to the present invention is manufactured in conventional cold forging process. The cold forging process is easy to manufacture and economically feasible.

In another aspect of the present invention, the valve spring retainer 306 according to a first aspect of the invention is done for single spring guiding design.

In still another aspect of the invention, the valve spring retainer 306 design according to a first aspect of the invention can also be done for seat valve springs and also for retainer valve springs with two springs guiding.

In another aspect, the valve spring retainer 306 is designed with 15 % reduced weight compared to the conventional valve spring retainer. Further, this retainer valve spring has adequate guidance for spring inner diameter guidance.

Thus, the present invention provides a retainer for maintaining the valve spring in compression which is having reduced weight, simple in design, and yet, sturdy enough to withstand the adverse operating conditions encountered within an internal combustion engine.

Part numbers associated with the description and drawings:

102. Engine 212. Fixed pulley

201.Crankcase 213. Fan

202. Cylinder block 301. Poppet valve

203. Cylinder head 302. Valve Seat

204. Left hand side crankcase 303. Valve head

205. Right hand side crankcase 304. Cylindrical stem

206. Crankshaft bearing 305. Return spring

207. Connecting rod 306. Spring retainer

208. Crankshaft 307. Outer tubular portion 209.Piston 308. Inner tubular portion

210. V- belt 309. Equidistant segments

211. Drive pulley

Claims:

1. A valve spring retainer 306 for internal combustion engine, the retainer
comprising:

an inner tubular portion 308;

an outer tubular portion 307 on the outer peripheral portion of the said retainer 306 for supporting a valve spring 305, wherein the outer tubular portion have characterizing segments formed by selectively removing mass from the outer periphery of the outer tubular portion 307 to join with the outer diameter of the inner tubular portion 308 to form a shape of segments projecting from inner tubular portion 308 that are equally distributed.

2. A valve spring retainer 306 as claimed in claim 1, wherein the said
valve spring retainer 306 is manufactured in cold forging process.

3. A valve spring retainer 306 as claimed in claim 1, wherein the said
valve spring retainer 306 is made of metal.

4. A valve spring retainer 306 as claimed in claim 1, wherein the said valve spring retainer 306 is made of polymer.

5. A valve spring retainer 306 as claimed in claim 1, wherein the said valve spring retainer 306 is applicable to single spring guiding design.

6. A valve spring retainer 306 as claimed in claim 1, wherein the said
valve spring retainer 306 is applicable to double spring guiding design.

7. A valve spring retainer 306 as claimed substantially as herein before
described with reference to and as illustrated in the accompanying
drawings.