Background Art In some transmission systems roller bearings or similar devices are used to mediate the engagement of a rotatable body, such as a gear-wheel, with a shaft about which the rotatable body is rotatably provided. Despite modem precision engineering techniques, the considerable rotational speeds involved in such systems generate appreciable quantities of frictional heat. It is one object of the present invention to provide a means for dissipating such heat.

The preceding discussion of the background to the invention is intended to facilitate an understanding of the present invention. However, it should be appreciated that the discussion is not an acknowledgement or admission that any of the material referred to was part of the common general knowledge in Australia as at the priority date of the application.

Throughout the specification, unless the context requires otherwise, the word "comprise"or variations such as"comprises"or"comprising", will be understood to imply the inclusion of a stated integer or group of integers but not the exclusion of any other integer or group of integers.

Disclosure of the Invention In accordance with the present invention there is provided a cooling system for roller bearings in a transmission system comprising at least one shaft, provided

about which are at least two rotatable bodies such that each roller bearing mediates the engagement of a rotatable body provided about a shaft, the cooling system comprising one or more seals, a pump and a heat exchanger, whereby the or each seal is provided about the shaft and is interposed between adjacent gear-wheels thereby creating a cavity through which a lubricant may be cycled, via the heat exchanger, by way of the pump.

In one form of the invention, the or each seal may be a labyrinth seal. In an altemate form of the invention, the or each seal may be provided in the form of a reduced gap between the adjacent gear wheels.

In a further form of the invention, each seal is annular in shape.

Preferably, where each seal is annular in shape, the cooling system of the present invention further comprises a sea recess, provided in a face of each gear wheel, whereby the seal recesses provided in opposing faces of adjacent gear wheels simultaneously partially receive one of said seals therein.

Preferably, the cooling system of the present invention further comprises one or more apertures provided axially through each roller bearing and adapted to facilitate the access of lubricant to the roller bearing.

In one form of the invention, the heat exchanger is provided in the form of a conventional oil cooler.

Brief Description of the Drawings The present invention will now be described, by way of example only, with reference to one embodiment thereof and the accompanying drawings in which: Figure 1 is a schematic cross sectional view of a transmission system equipped with a cooling system in accordance with the embodiment; and Figure 2 is a partial perspective view of a roller bearing of the transmission system of Figure 1.

Best Mode (s) for Carrying Out the Invention In Figures 1 and 2 there is shown a cooling system 10 in accordance with the embodiment. The cooling system 10 is provided in a transmission system 12 comprising a shaft 14, about which are provided seven gear-wheels 16. The engagement of each of the gear wheels 16 with the shaft 14 is mediated by a roller bearing 18. Each gear-wheel 16 comprises two faces 20.

The cooling system 10 comprises six annular seals 22, a pump 24 and a heat exchanger 26. Provided in each face 20, about the shaft 14, is an annular recess 28. Each annular seal 22 is partially received between the annular recesses 28 provided in the opposing faces 20 of adjacent gear-wheels 16, such that the six annular seals 22 and the seven gear-wheels 16 effectively form a sealed path 30 through which lubricant (not shown) may pass.

Each roller bearing 18 has provided axially extending therethrough, relative to the shaft 14, a plurality of apertures 32, adapted to facilitate the access of lubricant to the roller bearing 18.

In use, the pump 24 pumps the lubricant through the sealed path 30 and, via the apertures 32, through the roller bearings 18, thereby drawing frictional heat therefrom. The lubricant is then passed to the heat exchanger 26 where heat may be passed to a coolant fluid (not shown), such as air or water. The lubricant so cooled may be returned, by the action of the pump 24, to the sealed path 30 in a cyclical manner, thereby ensuring that the roller bearings 18 are maintained within an operational temperature range.

Modifications and variations such as would be apparent to the skilled addressee are considered to fall within the scope of the present invention.