Abstract:
Apparatus is disclosed for treating liquid lubricant in a supply of lubricant such as a gearbox including a filter, an inlet for supplying the lubricant to one side of the filter, and through the filter into a cavity, a lubricant cooler downstream pf the cavity so that the lubricant can pass from the cavity through the lubricant cooler for cooling, an outlet for the treated lubricant, a connector for transporting the lubricant from the lubricant cooler to the outlet, with the connector being disposed within the cavity.

Description:
FIELD OF THE INVENTION 
     The present invention relates to apparatus for the filtration and cooling of a liquid medium. The present invention is particularly intended for use in the field of motor vehicles, in particular for the filtration and cooling of oil that is utilized for lubrication of a gearbox. 
     BACKGROUND OF THE INVENTION 
     In a manner which is well known, oil is used in the field of motor vehicles for lubrication of, for example, the vehicle gearbox. For purification of the oil, an oil filter is normally used, through which the oil is caused to flow. During filtration, contaminants (for example in the form of solid particles) in the oil are separated from the liquid phase. The reason for this is that the oil is caused to pass through a porous layer in the oil filter, by means of which the contaminants remain in that layer. 
     For filtration of oil in the gearbox of a heavy goods vehicle, a so-called “spin-on-filter” is normally used, which is normally arranged on the outside of the gearbox and is connected to inlets and outlets for the oil that flows through the gearbox. The filter is constructed as a container, normally made of sheet metal, which contains an oil-filtering element in the form of a porous filtering material, through which the oil is fed. When the filter has been used for a period of time, it must be renewed, in which case the entire spin-on-filter is discarded and exchanged for a new filter. In this connection, the term “spin-on” refers to the fact that the filter-exchange is carried out by means of the filter being provided with a threaded portion, by means of which the filter can be screwed on directly during such an exchange. 
     Furthermore, in the case of trucks, there is in some cases also a need for cooling of the oil in the gearbox. In particular, such a need generally arises in countries having a warm climate, or in places where driving takes place in exceptionally exposed environments, for example in mines. According to known techniques, cooling of the oil is in this case carried out by means of an oil cooler being mounted between the gearbox pump and the oil filter. The oil that is utilized in the gearbox will thus be fed through the oil cooler, in which the oil is cooled down and is filtered in the oil filter. To this end, the oil cooler is provided with connections for an inlet and an outlet for a suitable refrigerant, for example water. In this case, the oil that is passing through the cooler can be cooled by the cooling water which is flushed through the cooler. 
     Although today&#39;s oil filters normally operate satisfactorily, they still have certain drawbacks. For example, the known type of spin-on-filter is not suitable to use due to environmental reasons, since the entire filter, including its casing, must be discarded when the filter must be renewed. 
     An additional drawback with this known technique is that the oil that is fed into the filter is relatively cold due to the fact that it has just passed through the cooler. Since cold oil is comparatively viscous, this provides for inferior flow through the oil filter. Furthermore, the oil that is fed through the oil cooler is contaminated, i.e. it is supplied directly from the gearbox and contains contaminants, for example in the form of particles. There is therefore a risk of these contaminants blocking the oil cooler, which can result in costly and undesirable breakdowns. 
     One of the objects of the present invention is thus to provide an improved device for cooling and filtration of a liquid medium, particularly oil, that is utilized in a motor vehicle, wherein the above-mentioned drawbacks are eliminated. 
     SUMMARY OF THE INVENTION 
     In accordance with the present invention, this and other objects have now been accomplished by the discovery of apparatus for treatment of a liquid lubricant in a supply of the lubricant comprising a filter having a first side and a second side, an inlet for supplying the lubricant from the supply of lubricant to the first side of the filter, whereby the lubricant can pass through the filter to the second side of the filter, the second side of the filter comprising a cavity, a lubricant cooler disposed downstream of the cavity, whereby the lubricant can pass from the cavity through the lubricant cooler for cooling therein, an outlet for the treated lubricant, and a connector for transporting the lubricant from the lubricant cooler to the outlet, the connector being disposed within the cavity. In a preferred embodiment, the connector comprises a detachable tube. 
     In accordance with one embodiment of the apparatus of the present invention, the apparatus includes a filter housing surrounding the filter, the filter housing adapted for mounting proximate to the supply of the lubricant, the lubricant cooler adapted for mounting on the housing distal from the supply of the lubricant, and the filter housing including at least one aperture for passing the lubricant from the filter to the lubricant cooler. In a preferred embodiment, the filter housing includes a tubular portion extending into the lubricant cooler, the tubular portion including at least one aperture whereby the cooled lubricant can pass from the lubricant cooler into the tubular portion. Preferably, the connector is detachably mounted within the tubular portion and at the outlet. 
     In accordance with another embodiment of the apparatus of the present invention, the filter is removably mounted within the filter housing. 
     In accordance with another embodiment of the apparatus of the present invention, the supply of lubricant includes a lubricant pump for pumping the lubricant to the inlet, the inlet including a passageway and a normally closed valve for selectively opening the passageway, whereby the normally closed valve is selectively opened when the pressure in the inlet exceeds a predetermined value. In a preferred embodiment, the passageway is in fluid communication with the supply of the lubricant. 
     In accordance with another embodiment of the apparatus of the present invention, a gear box for a vehicle has been discovered comprising the above apparatus, the liquid lubricant comprising oil flowing in the gear box. 
     The present invention is intended to be used for filtration and cooling of a liquid medium which preferably, but not exclusively, can constitute lubricating oil for a lubricated component, such as a gearbox. The present invention comprises an inlet for supply of the liquid medium to a filtering component, which defines a cavity to which filtered medium is guided. The present invention also comprises a cooling device and an outlet for supply of the medium back to the filtering component. A basic principle of the present invention is that the cooling device is arranged downstream of the cavity, wherein the cavity is connected to the cooling device and the cooling device is connected to the outlet. Due to the fact that the cooling device is arranged downstream of the filtering component, the entire amount of liquid medium will be filtered before it reaches the cooling device. Since the medium is filtered when it flows through the filtering device, there is basically no risk of contaminants accumulating and blocking the cooling device. 
     An additional advantage of the present invention is that it provides for an improved flow through the filtering component, which is due to the fact that the liquid medium is normally warm when it exits the gearbox and flows towards the filtering component. This, in turn, provides for an improved flow and an increased percolation through the filtering component, which in turn results in more effective filtration. 
     According to one embodiment of the present invention, the filtering component is arranged as a detachable part in a protector for the filter; i.e., the filtering component constitutes an insertion filter. This creates an environmental advantage, since only the filtering component, which for example can be produced from paper, has to be discarded in connection with a filter-exchange. 
     In this connection, the term “filtering component” refers to the component, for example in the form of a filtering paper, that is arranged inside a sleeve-like filter protector and through which the contaminated medium is supplied. The term “filter unit” refers to the component that consists of the filtering component and the filter protector, which is adapted for mounting in the component in which the medium is used, for example for lubrication. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will be described in detail in the following detailed description, which refers to the annexed drawing, which is a side, elevational, partial cross-sectional view of a device according to the present invention. 
    
    
     DETAILED DESCRIPTION 
     Turning to the drawing, FIG. 1 shows a cross-sectional view of a device according to the present invention, which, according to a preferred embodiment, constitutes a combined filter and cooling device for a liquid medium. The invention is primarily intended for use in connection with a motor vehicle, such as a heavy goods vehicle, for the filtration and cooling of oil in the vehicle gearbox. Thus, the drawing shows the casing  1 A of the gearbox  1 . An oil pump  2  is arranged in the interior of the gearbox, by means of which oil can be supplied from the oil pump to the device according to the present invention. The oil is used for lubrication of components forming part of the gearbox, such lubrication being carried out in a manner which is previously known and therefore will not be described here in detail. 
     The oil pump comprises a pump body  3 , a pump cover  3 A and a pump axle  4 , which is rotatably arranged in the pump body  3 . In a known manner, the pump axle  4  is driven by being connected to a driving axle  5 , which in turn is driven by an axle in the gearbox and ultimately by the vehicle motor (not shown). Also, the oil pump  2  contains a pump element in the form of a gear wheel  6 , which is arranged on a pump axle  4  and which also drives a ring-shaped gear wheel. Many other types of pumps are possible. The oil is supplied through an inlet  7  and pumped by means of the oil pump  2  in the direction of chamber  8  arranged downstream of the pump element  6 . 
     The device according to the present invention contains two main components, namely a filter unit in the form of an oil filter  9  and an oil cooler  10 . For mounting of these components on a gearbox, the casing  1 A is designed so that it forms an opening. The filter unit  9  is designed having an essentially tubular filter protector  11  which supports a similarly tubular filtering component  12  which is constructed of a filtering material, preferably filtering paper which in a known manner is designed for the separation of particles that are present in percolating, contaminated oil. The filtering component  12  is inwardly delimited by a stay tube  13  which is preferably composed of a perforated tube, which can, for example, be made of plastic or steel and is utilized to fix the filtering component in its intended form. 
     Furthermore, the end of the filter protector  11  that faces towards the gearbox, is designed as a sleeve, the shape of which corresponds to a circular edge  14  on the pump cover  3 A. Also, a circular seal  15  is arranged between the end part of the filter protector  11  and edge  14 . Furthermore the filter protector  11  is designed with a peripheral flange  16 , which is intended to bear against the outside of the casing  1 A when the filter and the cooling device according to the present invention is in its mounting position. 
     The oil cooler  10  according to the present invention is arranged at the end of the filter protector  11  which is not facing towards the gearbox  1 . For this reason, this end of the filter protector  11  is designed having a protruding part in the form of a tubular support sleeve  17 , which extends through the oil cooler  10 . As is apparent from the drawing, the support sleeve  17  is hollow. The outermost end portion of the support sleeve  17  is provided with threads, which cooperate with a nut  18 , which thus may be used to screw the oil cooler  18  together with the filter unit  9 . Outermost at the nut  18 , a plug  19  is arranged. Furthermore, a seal  20  is arranged between the nut  18  and the oil cooler  10 . 
     The oil cooler is previously known and comprises a fine-meshed net of channels (not shown), through which a cooling medium, preferably water, can be supplied. For the supply of this cooling medium, the oil cooler  10  is provided with a connection  21 , which constitutes an inlet for feeding the cooling medium into the oil cooler. This connection  21  is connected to a (not shown) cooling water container or coolant supply, which is arranged in connection with the gearbox. The oil cooler  10  also contains an additional (not shown) connection, which constitutes an outlet for feeding the cooling water out of the oil cooler  10  and back into the water container or the coolant supply. 
     By means of the pump  2 , the oil that is utilized to lubricate the gearbox is fed from the inlet  7  towards the chamber  8 . When the pump  2  is in operation, there is a risk of an abnormally high pressure in the chamber  8 . This may, for example, be the case during cold starts, when the oil is still cold and thus viscous. When the pressures in the chamber  8  are too high, there is a risk that damage may occur to the pump  2 . In order to reduce the risk of such damage, an overflow valve  22  is arranged in connection with the pump  2 . The valve  22  comprises a valve piston  23  which is movable in its longitudinal direction and which, in its natural state, blocks an opening  24  which connects the chamber  8  with the oil inlet  7 . By means of a spring element  25 , the valve piston  23  is biased to assume this state. The valve  22  is adapted so that it opens, i.e. is removed, at a predetermined pressure, for example  4  bar, whereby the opening  24  is no longer blocked. This results in the oil in the chamber  8  being guided back to the inlet  7  through channel  33 , which in turn results in the oil being rapidly warmed up, due to the fact that the oil is pumped around in this manner. By means of the increase in the oil temperature, the flowability of the oil also increases. The predetermined pressure, at which the valve piston  23  exposes the opening  24 , can preferably be adjusted by means of the choice of spring element  25 . 
     The filtration and cooling of oil according to the present invention will now be described with reference to the drawing. Oil having a normal pressure, and which is fed in through the chamber  8 , will be guided into the filter unit  9 . Here, the oil will pass through the filtering component  12 , which collects particles and other contaminants in the oil. The oil which is filtered in this manner will pass out towards an essentially tubular cavity  26  in the interior of the filtering component  12 . Here, the oil is fed in the direction indicated by the arrows in the drawings. 
     The filtered oil, which has thus passed through the oil-filtering component  12 , is further fed in the direction of the end of the cavity  26  that is farthest from the gearbox. Due to the fact that the filter protector  11  is provided with at least one, though preferably two or more, bored-out channels  27  and  28  which connect the filter protector  11  with the oil cooler  10 , the oil will be fed into the oil cooler  10 . Furthermore, the oil cooler  10  is designed with an essentially ring-shaped chamber  29  into which the oil is fed. The chamber  29  is arranged around the support sleeve  17  of the filter protector  11 . Furthermore, the part of the oil cooler  10  which is arranged downstream is designed so that the oil is guided towards the support sleeve  17 , which is provided with at least one, though preferably with a plurality, of openings  30  which allow oil to pass towards the interior of the support sleeve  17 , as indicated by an arrow in the drawing. 
     The interior of the support sleeve  17  is connected to an outlet  31  for oil, i.e. an outlet which guides the oil back into the gearbox and towards its different points of lubrication. The connection between the interior of the support sleeve  17  and the outlet  31  comprises a separate connection component in the form of an elongated tube  32 . The tube  32 , which preferably has a circular cross-section, is mounted so that one of its ends is arranged inside the support sleeve  17  and the other end is arranged in the pump body  3 , whereupon a tight connection is obtained between the tube  32  and the interior of the support sleeve  17 , and between the tube  32  and the outlet  31 , respectively. It is apparent from the drawing that the tube  32  extends through the inner cavity  26  inside the filtering component  12 . 
     By means of the present invention, the filtered oil that is present in the cavity  26  will be forced against the oil cooler  10  through the holes  27  and  28 , in which oil cooler the oil is cooled down. Furthermore, the oil is fed through the holes  30  into the interior of the support sleeve  17  and further into the tube  32 . In this manner, the oil will be guided through the tube  32  and towards the outlet  31 , whereupon the oil is guided further through the gearbox in a manner, which is not shown. 
     Due to the fact that the oil cooler  10  is arranged downstream of the filtering component  12 , the entire amount of oil will first be filtered, and then cooled down. This results in the oil which is filtered being warm, which results in an improved flow through the oil-filtering component. Furthermore, contaminants will be separated from the oil before the oil reaches the oil cooler  10 , which reduces the risk of the oil cooler being blocked due to accumulation of particles. 
     Since the filter unit  9  primarily only contains the filtering component  12  and the filter protector  11 , the filter unit also can be made environmentally advantageous. During exchange of an oil filter in a vehicle, the oil cooler  10  is initially removed, whereupon the filter protector  11  is removed from its place in the gearbox casing  1 A. Thereafter, the filtering component  12 , which, for example, is composed of filtering paper, is removed and discarded. This will result in a minimum of ecologically harmful waste. 
     The present invention is not limited to the embodiment, which is described above, but may be varied within the scope of the appended claims. For example, the invention may be utilized in different types of vehicles, and in principle also in applications which are not related to vehicles, but where it is desirable to filter and cool of a liquid medium intended for a lubricated component. 
     Furthermore, the present invention may be constructed so that the cavity, through which the oil is fed before it reaches the oil cooler  10 , can be arranged inside as well as outside the filtering component  12 , provided that the oil from the cooling device is fed to the outlet  31  through the cavity by means of a connection element. 
     Although the invention herein has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present invention. It is therefore to be understood that numerous modifications may be made to the illustrative embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims.