Oil pump sprocket float control mechanism

Field of the invention

The present invention relates to "Oil pump sprocket float control mechanism" and more particularly to an improved arrangement for the oil pump sprocket float control mechanism of the lubricating oil pump drive for a single cylinder internal combustion engine.

Background of the invention

Internal combustion engine is provided with an oil pump for sucking oil from an oil pan and sending it under pressure to lubricate and cool the parts of engine. The oil is stored in the oil pan under the engine, supplied to the various parts of engine and returned to the oil pan after achieving the lubrication and cooling of the parts of engine.

In the known type of internal combustion engines, the lubrication oil pump drive arrangements are made to ensure the oil supply by means of gear pumps or internally geared rotor pumps. Such known oil pump drives are expensive because they require corresponding transmission members; require additional installation space, etc. Furthermore, internally-geared rotor-pump arrangements are known in which the inner rotor is pressed onto the crankshaft and is mounted in the oil-pump housing together with the outer rotor, which leads to a complicated drive mechanism.

In order to eliminate the above-described lacunas, an oil pump drive is provided for an internal combustion engine having a continuous driving chain for connecting an oil pump drive chain wheel to an engine clutch shaft. A set of wear pads and float control brackets are provided for controlling and aligning the oil pump drive chain along the centreline; however the application of the aforesaid related art becomes difficult for construction owing to positioning the parts suitably for smooth running of the engine lubricating oil pump. The shaft along with sprocket can slide freely forward in the absence of any axial stopper. Also the construction of the said arrangements requires more number of parts that leads engine larger in size and results in increase in engine cost.

Hence the main objective of the present invention to provide an oil pump drive for an internal combustion engine with an improved sprocket float control mechanism for the continuous chain placed in oil pump drive arrangement with reduced number of parts and cost.

Another objective of the present invention is to provide a simple and inexpensive sprocket float control mechanism for drive chain of the oil pump for an internal combustion engine.

Brief description of the invention

The present invention relates to an improved single cylinder engine having a crankshaft and clutch shaft assembly. An oil pump sprocket is press fitted on to the oil pump rotor shaft; a clutch shaft sprocket through a continuous drive chain drives the oil pump sprocket. The clutch shaft sprocket is fitted on to the clutch shaft in the clutch housing of the internal combustion engine. The rotor shaft of the oil pump is driven directly by the continuous chain drive arrangement through the oil pump sprocket fitted on the oil pump rotor shaft and the clutch shaft sprocket fitted on the clutch shaft. A cover clutch is provided with a cavity for locating an oil filter with its axis nearly coinciding with the axis of the oil pump drive and projects towards oil pump drive sprocket. A pair of cylindrical projections is formed on the outer surface of the projected cavity facing the oil pump. The top most surface of the cylindrical projections almost touches the outer side of the sprocket thereby preventing axial movement of the sprocket along with the respective shaft.

Brief description of the drawings

Figure 1 illustrates partial cross section of the present invention

Figure 2 illustrates the pump drive system

Detailed description of the invention

A selected illustrative embodiment of the present invention will be now described with respect to the accompanying figure 1 and figure 2. The present invention relates to an internal combustion engine 101 that mounts a crankcase 112 and a crankshaft assembly 102 housed in the said crankcase 112 of the internal combustion engine 101. A clutch shaft assembly 103 is connected to crankshaft assembly 102 by means of a gear for meeting the drive and transmission requirements. A drive shaft is mounted on the adjacent axis of the crankcase 112 and is respectively connected to clutch shaft 103. The gear final drive and differential assembly is mounted on another axis of crankcase 112 and is connected to drive shaft through another set of gears.

A single cylinder internal combustion engine 101 comprises a crankshaft 102 and a clutch shaft assembly 103, an oil pump sprocket 104 is press fitted on to an oil pump rotor shaft 105; a shaft sprocket 106 through a continuous drive chain 107 drives the oil pump sprocket 104. The sprocket 106 is fitted on to the clutch housing 108 of the internal combustion engine 101. The rotor shaft 105 of the oil pump 110 is driven directly by the continuous chain drive arrangement 107 through the oil pump sprocket 104 fitted on the oil pump rotor shaft 105 and the sprocket 106 fitted on the clutch housing 108.

Accordingly for an Improved sprocket float control mechanism, the lubricating oil pump 110 is first mounted on the engine crankcase 112. The rotor of the oil pump 111 is provided with an D shaped opening at its centre and allows the rotor shaft 105 to fit with the oil pump rotor 111 for driving the oil pump 110.The rotor shaft is D shaped at the mating area with the rotor of the oil pump 111.

One end of the oil pump rotor shaft 105 passes through the oil pump outer : housing and locates in the rotor 111 of the oil pump 110. Other end is provided with a collar 113 larger than the diameter of the oil pump rotor shaft 105. One side of the collar 113 of the oil pump shaft 105 faces the oil pump outer cover with a normal running gap and other side of the said collar 113 locates the sprocket 106 for driving the oil pump rotor 111.
The distance between sprocket locating collar face to edge of the shaft on oil pump drive sprocket 104 fitting side is lesser than the thickness of the oil pump driving sprocket 104. The collar end 113 of pump shaft 103 is provided with threaded hole for tightening the sprocket 106 on to the said pump shaft 105. A bolt is inserted into the threaded hole of the shaft and tightened over the sprocket face to clamp it on to oil pump drive shaft 105 firmly. The entire assembly of shaft 105 along with sprocket and bolt is inserted into the oil pump 110 that locates on the oil pump rotor gear 118. The shaft along with sprocket can slide freely forward in the absence of any axial stopper and hence to prevent the axial movement of sprocket 104 and shaft assembly, a cover clutch 114 is provided with a projected cavity 115 for locating an oil filter 116 with its axis nearly coinciding with the axis of the oil pump drive 110 and projects towards oil pump drive sprocket 104. A pair of cylindrical projections 117 is formed on the outer surface of the projected cavity 115 facing the oil pump 110. The top most surface of the cylindrical projections 117 almost touches the outer side of the sprocket 104 thereby preventing axial movement of the sprocket along with the respective shaft.

This sprocket float control is defined by pair of cylindrical projections 117 formed on the outer surface of the projected cavity 115 facing the oil pump 110, which effectively control and align the chain 107 in one line or along the ; centreline for maintaining the smoothness during the pumping process.

The present invention allows for providing a simple and inexpensive sprocket float control mechanism for drive chain of the oil pump, with easiness for; serviceability and increased reliability for an internal combustion engine.

The improved oil pump sprocket float control mechanism allows for providing a compact and positive drive arrangement with less number of parts, and hence reducing the size and cost of the engine.

Part numbers associated with the description and drawings:

101 - Engine 111 - Rotor of oil pump
102-Crankshaft 112-Crankcase
103- Clutch shaft assembly 113- Collar
104-Oil pump sprocket 114-Clutch cover
105-Oil pump rotor shaft 115-Cavity in oil filter
106-Shaft sprocket 116- Oil filter
107-Continuous drive chain 117- Cylindrical projection
108-Clutch housing 118- Oil pump rotor gea
110-Oil pump

Claims:

We claim:

1. An oil pump sprocket float control mechanism for an internal combustion engine comprising

a crankshaft 102 and clutch shaft assembly 103;

an oil pump sprocket 104 slide fitted on to a oil pump rotor shaft 105;

the said oil pump sprocket 104 driven by sprocket 106 fitted on a clutch housing 108 on clutch shaft 103 through a continuous drive chain 107;

the rotor 111 of an oil pump 110 is provided with an opening at its centre and allows the rotor shaft 105 to fit with the oil pump rotor for driving the oil pump 110;

a cover clutch 114 provided with a projected cavity 115 for locating an oil filter 116 with its axis nearly coinciding with the axis of the oil pump 110 and projects towards oil pump drive sprocket 104;

a pair of cylindrical projections 117 is formed on the outer surface of the ; projected cavity 115 facing the oil pump 110, wherein the top most surface of the cylindrical projections 117 almost touches the outer side of the sprocket 104 thereby preventing axial movement of the sprocket along with the respective shaft.

2. The cover clutch 114 as claimed in claim 1, wherein the cover clutch 114 is made of metal.

3. The cover clutch as claimed in claim 1, wherein the gap between the oil pump sprocket and the pillar is just enough to allow the rotation of the oil pump drive sprocket 104.