ARRANGEMENT IN AN OIL FILTER

Abstract: The invention relates to an arrangement in an oil filter (1) for a machine with a centralised lubrication system, for example an internal combustion engine. The filter comprises a cylindrical container enclosing a filter material (2), one end (1b) of the container having a peripheral seal (1b1) arranged in an end section of the container wall (1a), and a central threaded sleeve (1b2) serving as outlet for oil that has passed through the oil filter (1). Furthermore there is between the sleeve (1b2) and the seal (1b1) at least one inlet opening (1b3) for oil which is to be filtered. The end (1b) comprises a circular plate (6). The sleeve (1b2) engages with or forms an integral part of the plate (6), which in turn at its periphery bears against the end section (1a2) of the container wall (1a) on that side of the said end section opposite the seal (1b1). The plate (6) has a pattern which is formed by ridges extending essentially radially with intervening channels. In this connection a peripheral part of the tops of the ridges is engaged in the bearing against the end section (1a2) of the container wall (1a) and the channels form inlet openings (1b3) for the oil.

Description: Arrangement in an oil filter The present invention relates to an arrangement in an oil filter according to the pre- characterising part of claim 1. The purpose of such an oil filter is to trap particles in the lubricating oil in order thereby to prevent unnecessary wear in the crank bearings, valve timing gear and other moving parts of an internal combustion engine. In the case of motor vehicle engines this generally involves replaceable, disposable filters comprising a paper-metal filter enclosed in a crimped metal casing, preferably of sheet steel. Such a filter is screwed on to an inlet pipe, projecting from the engine block, for the oil that has been cleaned in the filter. Around the said pipe the engine block has a raised shoulder, against which the filter seal seals off incoming oil that flows into the filter via one or more ports in the engine block, which are situated between the outlet pipe and the sealed shoulder. As the filter material becomes increasingly mixed with carbon particles from burnt oil and metal particles from the engine, it must be changed. When the oil filter is to be changed after the prescribed interval it is generally filled with contaminated oil. Handling the said used oil filters presents a number of awkward problems. In practice, used oil filters cannot be burned, since they are unsuitable from the combustion point of view and the end products, possibly with heavy metal residues, would be steel containers, not readily oxidizable, which are unattractive from the point of view of recycling, since they have a low recycling value and a large transport volume. Attempts have been made to improve the waste treatment by pressing the oil out of the filter container, thereby making it easier to burn, but leaving from each filter a compressed steel body with oil residues that is unsuitable for treatment in a metallurgical recycling process and makes environmental long-term tipping virtually unfeasible. One reason why used oil filters represent a relatively large weight of contaminated steel is that the filter casing, the function of which is to guide and distribute the oil coming from the engine via the filter material and then return the oil to the engine, must be able to withstand the working pressure of the oil and also the forces that occur due to engine vibrations. The lower end part of the filter casing in particular must be able to absorb CONFIRMATION COPY 2 not only the above-mentioned forces but also those forces that occur due to the tightening torque required in order to fit the oil filter to the engine. For this reason this end is made of relatively thick sheet steel in the order of thickness of 3 mm or more and pressed to a shape which allows the oil, from a number of small openings close to the centre of the filter, to change its direction of flow away from the centre before being guided up along the wall of the filter container and distributed over the surface of the filter material. Accordingly, in known oil filters the lower end part is made of relatively thick material and has a design shape entailing relatively high manufacturing costs and pressure drops. The object of the present invention is to produce an improved and simplified design shape of the lower end of the oil filter with an improved oil flow pattern and a reduced pressure drop in the filter inlet section. This is achieved by means of the characteristic features set out in the characterising part of claim 1. The invention will be further explained below with reference to the attached drawing in which figure 1, in a perspective view, shows one embodiment of the lower end of the oil filter. Figures 2a and 3 a show respectively a longitudinal section through the arrangement according to the invention in a disposable filter and a filter with changeable filter material, whilst figures 2b and 3b show detailed views of figures 2a and 3a respectively. In the drawing 1 generally denotes an oil filter according to the invention. This comprises a cylindrical container with a cylindrical wall la and two ends lb and lc. In the embodiment shown in figure 2a the end lc is firmly connected to the wall la whilst in the embodiment according to figure 3 a it can be removed and fitted like a cover, as will be explained later in connection with the last figure mentioned. The container encloses a filter material 2, which is composed of paper impregnated with thermosetting plastic and folded in order to obtain a sufficiently large filter surface. The filter material is in the form of a thick-walled tube with a central duct 2a and the outside diameter of the tube is selected so that there is a space lal between the filter material and the wall la. The end lb has a peripheral seal lbl , which is fixed in an annular groove formed in an end section la2 of the wall la. The said end section, which in the embodiment according to figure 2a is crimped to the cylinder wall 1 a but in the embodiment according to figure 3a forms an integral part of the latter, generally forms an inwardly 3 directed annular flange. Centrally located in the end lb is a threaded sleeve lb2, which serves as outlet for the oil that has passed through the oil filter. Between the sleeve lb2 and the seal lbl, more specifically in an area at the end section la2, are a number of inlet openings lb3 for the oil to be cleaned. When the oil filter is fitted to an internal combustion engine, for example, the sleeve lb2 is joined by means of threaded connection to an inlet pipe 3 projecting from the engine, for filtered oil, and the seal lbl bears tightly against a raised shoulder 4 on the engine block. Oil to be filtered flows through a duct 5, which surrounds the inlet pipe 3 and connects with the engine lubrication points. According to the invention the end lb comprises a circular plate 6, which has been pressed to give it a pattern of radially extending ridges 6a with intervening channels 6b. A peripheral part 6al of the tops of the ridges bears against the end section la2 of the container wall on that side of the said end section opposite the seal lbl and corresponding peripheral parts of the channels 6b form inlet openings lb3 for the oil. In the embodiments according figures 2a and 3a the detailed design shape of the plate 6 differs in certain respects, for which reason reference will first be made to the embodiment according to figures 2a, 2b, which as already stated relates to a disposable filter. The plate 6 generally has the design shape shown in figure 1. Here the sleeve lb2 is an integral part of the plate, to be more precise an axially pointing annular flange. This is provided with an internal thread in which an external thread of the inlet pipe 3 fits. The filter material 2 has ends 2b, 2c, of which 2c rests on an annular casing 7, which in turn engages with the sleeve lb2, which as stated constitutes an integral part of the plate 6. In this way the filter material is held between the ends lb and lc. A flow of oil from the engine, which in figure 2a is indicated by arrows 8a, flows up through the duct 5 and arrives by way of the openings lb3, that is the channels 6b, at the space lal , where the oil is distributed over the surface of the filter material 2. Having passed through the filter material 2, the filtered oil, the flow of which is indicated by arrows 8b, is collected in the duct 2a and reaches the outlet pipe 3 in an aggregate flow indicated by an arrow 9. 4 As stated, the oil filter according to figure 3a is provided with an end lc serving as cover, in order to permit changing of the filter material. As in the embodiment according to figure 2a, this is provided with ends 2b, 2c. A tube 10, which is provided with openings 10a and at one of its ends is firmly screwed into the sleeve lb2, extends axially through the filter. The other end of the tube 10 is provided with threads, which fit into threads in a central sleeve lcl on the end lc, so that the end lc can be screwed fast, tightening of the threaded connection preventing leakage between the end lc and the cylindrical wall 1 a by means of a seal 11 in the form of an O-ring located in a peripheral groove in the end lc. A spring washer 12 arranged on the sleeve lcl is designed to press against the end 2b of the filter material 2 when the end lc is in the tightened state. The end 2c of the filter material 2 rests with an inner edge against an annular flange lb4 on the sleeve lb2. The plate 6 is clamped between the annular flange lb4 and the end section la2 of the container wall la, on the side opposite the seal lbl. As will be apparent from what has been said above, the design shape of the end lb according to the invention can be used both in filters of the disposable type and in filters with changeable filter material. The plate 6, which constitutes an essential part of the invention, may be modified within the scope of the idea of the invention, for example by means of more or fewer ridges. Likewise the ridges, for example, can be made wider than the channels, the appearance of which will obviously be reversed viewed from the other side of the plate 6. It is important, however, that the pressed pattern give the plate 6 a rigidity which is at least equal to or greater than that of the corresponding end in known oil filters, despite the fact that the plate material is relatively thin.

Claims: Claims 1. Arrangement in an oil filter (1) for a machine with a centralised lubrication system, for example an internal combustion engine, comprising a cylindrical container enclosing a filter material (2), one end (lb) of the container comprising a circular plate (6), which is provided with radial ridges with intervening channels and which has a peripheral seal (lbl) arranged in an end section of the container wall (la), a central threaded sleeve (lb2) serving as outlet for oil that has passed through the oil filter (1), and between the sleeve (lb2) and the seal (lbl) at least one inlet opening (lb3) for oil which is to be filtered, characterised in that the sleeve (lb2) engages with or forms and integral part of the plate (6), which in turn at its periphery bears against the end section (la2) of the container wall (la) on that side of the said end section opposite the seal (lbl) and that a peripheral part of the tops of the ridges is engaged in the bearing against the end section (la2) of the container wall (la) and that the channels in the said end section (la2) form inlet openings (lb3) for the oil. 2. Arrangement according to claim 1, characterised in that the engagement of the sleeve with the plate comprises an annular flange arranged on the sleeve. 3. Arrangement according to claim 1 or 2, characterised in that the pattern of the plate (6) is made by pressing.

Inventors: HEDMAN ERIK, HEDMAN, ERIK
Applicants: HEDMAN ERIK, PUROLATOR PRODUCTS CO, HEDMAN, ERIK, PUROLATOR PRODUCTS COMPANY
Application year: 1999
Main classification: B01D27
IPC codes: B01D27