Field of the Invention

The present invention refers to an oil pump, to be driven by the crankshaft of an internal combustion engine, to draw lubricant oil from the interior of the engine crankcase, forcing the oil to pass through an oil filter and to reach different internal engine parts which require lubrication. The invention further refers to an oil filter to be operatively associated with an oil pump of an internal combustion engine.

Prior Art

There are well known in the art oil pumps of the type considered herein and mentioned above, generally gear pumps, having a housing provided with an oil outlet in which is connected, generally by threads, the inlet of an oil filter, whose body is thus directly and externally affixed, in a removably way, to the pump housing .

This known type of oil pump construction requires the provision of a pressure control means defined by a relief valve, mounted in a bypass which connects the inlet with the outlet of the oil filter. Thus, when there is an eventual obstruction of the oil filter and the consequent pressure increase at the pump outlet, the relief valve is automatically opened, allowing the pump to continue working, pumping oil to the interior of the engine through the relief valve mounted in the bypass of the oil filter.

The oil pumps of the type considered herein are also operatively associated with a check valve (or nonreturn valve) , disposed in the oil pumping circuit, so as to prevent the the return of the oil, upon the engine stop, that is, upon the pump stop, from the interior of the filter to the inside of the engine crankcase. Thus, upon an engine restart, the oil filter will be full of oil, allowing the latter to be rapidly supplied to the internal engine parts. Otherwise, if the oil is allowed to return to the interior of the pump or crankcase upon the engine stop, at the time of an engine restart, the pump will have to fill up the oil filter with oil, which will be then sent to the engine parts to be lubricated. This delay in the lubrication, upon engine starts, tends to produce premature wear of the movable engine components which were not submitted to an adequate lubrication .

Nowadays, there are used shielded-type oil filters, which are directly removably coupled to the oil pump housing and present an inlet nozzle connected to the pump outlet, and an outlet nozzle connected to the system which conducts the oil to the interior of the engine .

The current shielded filters are constructed with a housing which lodges, in its interior and in a non- detachable way, a filtering element, a check (or nonreturn) valve, disposed in the region of the filter inlet nozzle, and a relief or bypass valve, establishing a . selective and direct fluid communication of the inlet nozzle of the filter with its outlet nozzle.

Due to the shielded construction of the known oil filters, at the end of its useful life, the whole filter, including the housing, the filtering element, and the relief valve and check valve, has to be discarded and replaced by a new shielded filter. Thus, all the filter material is discarded, increasing the amount of environmentally aggressive material, as well as the filter cost to the end consumer.

Summary of the Invention As a function of the drawbacks mentioned above, it is one of the objects of the present invention to provide an oil pump for internal combustion engines, comprising an oil filter, operatively associated with the relief and check valves, and presenting a filtering element which can be replaced, without requiring replacing the other filter component parts, generally defined by the housing and by said relief and check valves.

The present invention also has the object of providing an oil filter, operatively associated with relief and check valves, to be coupled to the housing of an oil pump for internal combustion engines and having, as one of its component parts, a filtering element which can be replaced, without requiring the replacement of its other component parts and of said relief and check valves .

These and other objects of the present invention are associated with an oil pump, to be applied in internal combustion engines and presenting a housing provided with a dirty oil inlet; a dirty oil outlet; a dirty oil duct, having an inlet, opened to the dirty oil outlet, and an outlet; and, a clean oil duct, having an inlet opening and an outlet opening for conducting the clean oil to the interior of the engine.

According to the invention, the oil pump comprises: a check valve provided in the dirty oil duct, for allowing the oil to flow only towards the outlet opening of the dirty oil duct, preventing the oil from flowing in the opposite direction when the pump stops working; an oil filter having a tubular body removably affixed to the housing and opened to the outlet of the dirty oil duct, and a filtering element removably mounted in the interior of the tubular body and having a dirty oil inlet, opened to the interior of the tubular body, and a clean oil outlet, opened to the inlet opening of the clean oil duct; and a relief valve mounted in the interior, of the tubular body and communicating the interior of the latter with the clean oil outlet of the filtering element, when the hydraulic pressure, in the interior of the tubular body, reaches a certain value.

The construction proposed by the invention, and defined above, allows the filtering element to be the only periodically replaced component of the filter, preventing the filter housing, and the check and relief valves from being discarded, as it occurs with the shielded oil filters currently used in the internal combustion engines, in association with the oil pumps. The proposed construction allows saving maintenance costs and produces a lower amount of waste generated in the maintenance stations.

Brief Description of the Drawings

The invention will be described below, with reference to the enclosing drawings, given by way of example of a possible embodiment of the invention and in which: Figure 1 is front view of the pump of the invention, provided with an oil filter, and with a relief valve and a check valve;

Figure 2 is a view similar to that of figure 1, but with part of the pump housing being transversely cut, to better illustrate the dirty oil duct and the clean oil duct;

Figure 3 is a longitudinal sectional view of the oil filter and relief valve, and a cross-sectional view of the check valve; and

Figures 4 and 5 are longitudinal sectional views of the check valve, in the closed position and in the open position, respectively;

Description of the Invention As illustrated and already previously described, the present oil pump B is applied to internal combustion engines, to be driven, for example, by the engine crankshaft, by means of any adequate mechanical arrangement, which may be known or not in the prior art .

The oil pump B is of the type which has a housing 10 provided with a dirty oil inlet 11, maintained in fluid communication with the crankcase (not illustrated) of the internal combustion engine, so as to draw therefrom the lubricant oil to be pumped to the internal engine parts to be lubricated. The housing 10 is also provided with a dirty oil outlet 12, through which the oil is discharged, in a pressurized condition, from a pumping chamber (not illustrated) of the oil pump B, which chamber can be constructed in different ways, whether known or not, but capable of meeting the operational requirements demanded by the engine design.

The type of oil pump B considered herein also presents a dirty oil duct 13, having an inlet 13a, open to the dirty oil outlet 12 of the housing 10, and an outlet 13b to be commented ahead, and a clean oil duct 14, having an inlet opening 14a and an outlet opening 14b for conducting clean oil to the interior of the engine .

The housing 10 of the oil pump B can be formed by different ways such as, for example, by injection of an aluminum alloy, and can be configured so that the dirty oil duct 13 and clean oil duct 14 are defined by respective passages formed in the interior of an extension of the housing 10.

According to the invention, the oil pump B comprises a check valve 20 provided in the interior of the dirty oil duct 13, in order to allow the oil, pressurized by the oil pump B, to flow only towards the outlet 13b of the dirty oil duct 13. In the illustrated construction, the check valve 20 presents a seat 21, defined in the interior of the dirty oil duct 13, and a sealing means 22 which is displaced, in the interior of the dirty oil duct 13, between a closed position, seated against the seat 21, interrupting the fluid communication between the dirty oil duct 13 and the dirty oil outlet 12 of the housing 10, upon the stop of the oil pump B, and an open position, spaced from the seat 21 and allowing said fluid communication upon operation of the oil pump B.

The dirty oil duct 13 is preferably rectilinear, with an end defining the inlet 13a of said duct and forming, with the dirty oil outlet 12 of the housing 10, the seat 21 of the check valve 20, and with an opposite end closed by a removable cap 15. In this type of construction, the outlet 13b of the dirty oil duct 13 is radially disposed downstream of the seat 21.

As illustrated, the sealing means 22 of the check valve 20, generally in the form of a cylindrical piston, carrying an end sealing ring 22a and formed in any adequate material, metallic or polymeric, is constantly forced to the closed position, for example, by means of a spring element 23, disposed in the interior of the dirty oil duct 13 and having opposite ends respectively seated on the cap 15 and on the sealing means 22. The spring element 23 is dimensioned to be elastically deformed, allowing for the displacement of the sealing means 22 and for the opening of the seat 21 of the check valve 20, for the passage of the oil flow towards the outlet 13b of the dirty oil duct 13, upon the operation of the oil pump B. With the stop of the oil pump B and interruption of the hydraulic pressure against the sealing means 22, the spring element 23 forces the sealing means 22, more specifically its end sealing ring 22a, to seat against the seat 21, preventing the oil from returning to the interior of the oil pump B and back to the engine crankcase.

The present pump further comprises a filter 30, having a tubular body 40 removably affixed to the housing 10 and opened to the outlet 13b of the dirty oil duct 13, and a filtering element 50 removably mounted in the interior of the tubular body 40 and having a radial inlet of a radial dirty oil inlet 50a, opened to the interior of the tubular body 40, and a clean oil outlet 50b, opened to the inlet opening 14a of the clean oil duct 14.

Also making part of the present oil pump B, it is provided a relief valve 60 mounted in the interior of the tubular body 40 and communicating the interior of the latter with the clean oil outlet 50b of the filtering element 50, when the hydraulic pressure in the interior of the tubular body 40 reaches a certain value .

According to the exemplary construction, illustrated in the drawings, the filtering element 50 is in the form of a tubular cartridge constructed in a filtering material suitable for the application and presenting: closed and opposite annular end faces 51, with one of them being maintained seated against the housing 10 of the oil pump B; an external peripheral face 52, defining the radial dirty oil inlet 50a of the filtering element 50, from the interior of the tubular body 40 of the oil filter 30; and an internal peripheral face 53, which defines a filtered oil radial outlet 50c of the filtering element 50 and the lateral wall of a central duct 55, having an open outlet end 55b defining the clean oil outlet 50b of the filtering element 50 and coupled to the inlet opening 14a of the clean oil duct 14, and an opposite end 55a, in which is adapted the relief valve 60, defining a selective and direct fluid communication between the interior of the tubular body 40 of the oil filter 30 and the interior of the central duct 55, formed in the interior of the filtering element 50. The tubular body 40 of the oil filter 30 comprises: a base portion 41, incorporated to the housing 10 and having its interior kept in communication with the outlet 13b of the dirty oil duct 13; and a lid portion

42, in the form of a cylindrical cup, and to be tightly and removably coupled to the base portion 41. The base portion 41 and the lid portion 42 of the tubular body 40 of the oil filter 30 are provided with respective threads 41a, 42a, to be tightly engaged to each other, upon coupling the lid portion 42 to the base portion 41. The tightness in the coupling region of the lid portion 42 with the base portion 41 can be better ensured with the provision of a sealing ring

43, generally in elastomer and positioned between said lid portion 42 and base portion 41 and radially compressed therebetween.

In the illustrated construction, the relief valve 60 comprises a valve body 61, constructed in metallic or polymeric material and having an inlet end 61a opened and seated against the lid portion 42 of the tubular body 40 of the oil filter 30, and an outlet end 61b, seated against the adjacent end annular face 51 of the filtering element 50 and defining a seat 62 opened to the interior of the central duct 55. The relief valve 60 further comprises an obturator 63, operatively cooperating with the seat 62, and a spring element 64, forcing the obturator 63 against the seat 62 and maintaining the latter closed, while the hydraulic pressure in the interior of the tubular body 40 of the oil filter 30 is inferior to a certain value.

The relief valve 60 defines a bypass for the filtering element 50 and allows that, in case the latter is clogged, the oil being pumped by the oil pump B continues to flow through the oil filter 30, to the interior of the engine to be lubricated.

As already previously mentioned, one aspect of the present invention refers to an ^" oil pump of the type which comprises a housing 10 provided with: a dirty oil inlet 11; a dirty oil outlet 12; a dirty oil duct 13, having an inlet 13a open to the dirty oil outlet 12, and an outlet 13b; and a clean oil duct 14, having an inlet opening 14a and an outlet opening 14b for conducting the clean oil to the interior of the engine.

Other aspect of the invention refers to an oil filter to be used together with an oil pump, of the type which comprises a housing 10, provided with a dirty oil inlet 11 and a dirty oil outlet 12 and operatively associated with a dirty oil duct 13, having an inlet 13a, opened to the dirty oil outlet 12, and an outlet 13b, and a clean oil duct 14, having an inlet opening 14a and an outlet opening 14b for conducting the clean oil to the interior of the engine. The oil filter 30 presents the construction already previously defined in the present specification and exemplified in the enclosed drawings, and which may be applied to a housing incorporating, in its interior, the dirty oil duct 13 and the clean oil duct 14, or to a housing operatively associated, in any other manner, with said ducts .

The different constructive possibilities of the invention, as described herein, may be presented as individual solutions, or partially or totally combined to each other.

While only one possible embodiment of the invention has been illustrated herein, it should be understood that changes can be made in the form and arrangement of the component parts of the oil pump and oil filter, without departing from the scope of the invention, as defined in the claims that accompany the present disclosure .