Claims:We claim:
1. A drive arrangement (100) for a supercharger (102), comprising at least:
a housing (104) comprising at least one inlet (106) to receive hydraulic fluid and an outlet (108);
a drive element (110) located within said housing (104) and adapted to be driven by said hydraulic fluid;
at least one shaft (112) fitted to at least one part of said drive element (110) and extending from said housing (104) in a manner such that at least one lobe (114) of said supercharger (102) is fitted to an end of said at least one shaft (112) extending from said housing (104) of said drive arrangement (100).

2. The drive arrangement (100) of claim 1, wherein said drive arrangement (100) is attached to the casing (118) of said supercharger (102).

3. The drive arrangement of claim 1, wherein a sealing element (116) located in between said drive element (110) and said at least one lobe (114) of said supercharger (102).

4. The drive arrangement of claim 1, wherein said drive element (110) is at least one chosen from a gear drive, and a vane pump.

5. A supercharger (102), comprising at least:
at least one shaft (112), comprising at least one lobe (114) mounted on said shaft (112); characterized in that
a drive arrangement (100) adapted to rotate said at least one shaft (112), said drive arrangement (100) comprising at least:
a housing (104) comprising at least one inlet (106) to receive hydraulic fluid and an outlet (108); and
a drive element (110) located within said housing (104) and adapted to be driven by a hydraulic fluid and fitted to at least an end said shaft (112) located within said housing (104). , Description:Field of the invention
[0001] This invention relates to the field of superchargers and drive arrangement for superchargers.

Background of the invention
[0002] Superchargers driven by crankshaft of the engine are known in the art. From the crankshaft a mechanical belt and pulley arrangement is used to transmit power from the crankshaft so as to rotate the shaft of the supercharger. The rotation of the supercharger shaft, causes the lobes of the supercharger to rotate, thereby causing air to be sucked in and compressed in the supercharger. This separate drive from the engine, for functioning of the supercharger requires additional space and effort. Hence there is need for a simple and efficient drive arrangement in a supercharger.

[0003] Prior art patent application US4671137 discloses a drive device of variable transmission ratio, particularly for operating an internal combustion engine supercharger. The drive device consists of a rotating casing containing a fluid and carrying internally in an idle manner a sun gear and a pair of respective planet gears which mesh with the sun gear and define a gear pump therewith; the fluid is contained in an inner reservoir of the casing, and this latter is provided, in correspondence with the meshing zones between the planet gears and sun gear, with respective intake chambers connected to the reservoir and with delivery chambers closed by automatic valves which are kept closed by the preloading of a spring against a ball and arranged to open at a predetermined pressure in order to connect the delivery chambers to the reservoir. A pneumatic device also controls a respective shut-off valve in order to connect the delivery chambers to the reservoir independently of the opening of the automatic valves.

Brief description of the accompanying drawing
[0004] Different modes of the invention are disclosed in detail in the description and illustrated in the accompanying drawing:

[0005] FIG. 1 illustrates a supercharger with the drive arrangement; and
[0006] FIG. 2 illustrates working of the drive arrangement.

Detailed description of the embodiments
[0007] FIG. 1 illustrates a drive arrangement 100 for supercharger 102. The drive arrangement 100 comprises at least a housing 104 comprising at least one inlet 106 to receive hydraulic fluid and an outlet 108. A drive element 110 is located within the housing 104 and adapted to be driven by the hydraulic fluid. The drive element 110 may be a gear drive or a vane pump. At least one shaft 112 is fitted to at least one part of the drive element 110 and extends from the housing 104 in a manner such that at least one lobe 114 of the supercharger 102 is fitted to an end of the shaft 112 extending from the housing 104 of the drive arrangement 100. The drive arrangement 100 is attached to the casing of the supercharger 102. A sealing element 116 is located in between the drive element 110 and the lobe 114 of the supercharger 102.

[0008] The constructional details of the drive arrangement 100 for the supercharger 102 will now be described in further detail. The supercharger 102 comprises at least one shaft 112 with a lobe 114 mounted on the shaft. The drive arrangement 100 is adapted to rotate the shaft 112 and comprises at least a housing 104, the housing 104 comprises an inlet 106 for receiving the hydraulic fluid, for example, the engine oil and an outlet 108. The profile of the inlet 106 is such that once the oil is received, the oil can be easily directed onto the drive element 110. The drive element 110 located within the housing 104 and is adapted to be driven by a hydraulic fluid and fitted to at least an end the shaft 112 located within the housing 104. The drive arrangement 100 is attached to the casing 118 of the supercharger 102. The drive arrangement 100 may be permanently and/ or temporarily attached to the casing 118 of the supercharger 102. The drive arrangement 100 also houses a shaft 112. The shaft 112 is fitted to at least one part of the drive element 110 and extends from the housing 104 in a manner such that at least one lobe 114 of the supercharger 102 that is fitted to an end of the shaft 112 extending from the housing 104 of the drive arrangement 100. In other words, the shaft 112 is common to both the drive element 110 and the lobe 114 of the supercharger 102. That is the shaft 112 extends within the housing 104 of the drive arrangement 100 and the casing 118 of the supercharger 102. The shaft 112 is provided with at least one sealing element 116. The sealing element 116 prevents the oil from the drive arrangement 100 from entering into the casing 118 of the supercharger 102.

[0009] FIG. 2 illustrates working of the drive arrangement 100. The drive arrangement has an inlet for receiving the oil. The oil impinges onto the drive element (a gear drive, for example) and causes the gears to rotate. Since the gear is mounted on the shaft 112, the shaft 112 rotates causing the lobes 114 of the supercharger that are mounted in the supercharger casing 118 to rotate thereby causing air to be sucked in for compression.

[00010] The working of the supercharger 102 with the drive arrangement 100 will now be explained in further detail. As, explained in the detailed description of FIG. 1, the proposed supercharger 102 is driven hydraulically. The engine oil that is used for lubrication of the components of the engine, may be used a hydraulic source. The oil, from the oil pump is flows to the inlet 106 of the housing 104. In case a variable oil pump is used, the speed of the supercharger 102 can be varied and can be adjusted to achieve the expected combusting engine intake air flow and intake pressure. From the inlet 106, the forced circulation of oil, causes the oil to impinge on the drive element 110. The drive element 110 may be a gear drive or a vane pump. For the purpose of understanding the drive element 110 is to be understood as a gear drive. As the oil impinges on the toothed elements of the gear drive, the gear drive starts rotating. The rotation of the gear drive causes the shaft 112 on which the gear drive is mounted to rotate. As the shaft 112 rotates, the lobes 114 of the supercharger 102 that are also fitted onto the shaft 112 also rotate causing air to be sucked in and compressed in the supercharger 102. By varying the rate of flow of oil through the drive element 110, it is possible to drive the supercharger 102 at varying speeds. The lubrication of supercharger bearings and the sealing capacity of the sealing element 116 increases as the load and speed of the supercharger 102 increases. This is because higher the speed, more amount of oil passes through the drive element 110. At higher speeds, the pressure differential in the supercharger is also very high, due to this the sealing element is pressed tight and hence efficiently seals the supercharger 102 against any flow of oil.

[00011] It should be understood that embodiments explained in the description above are only illustrative and do not limit the scope of this invention in terms type of drive element used and the different varieties of engines. Many such embodiments and other modifications and changes in the embodiment explained in the description are envisaged. The scope of the invention is only limited by the scope of the claims.