AIR FILTER DEVICE FOR INTAKE AIR FOR AN ENGINE

Abstract: An air filter device (110) for intake air for an engine comprising a filter supporting member (112) extending within a filter placing frame constituted by an external frame structural member (111) and a filter (113) supported by the filter supporting member (112), wherein the filter (113) is integrally joined to the filter supporting member (112), whereby it is possible to prevent the occurrence of a dusting phenomenon of the filter in the filter device and breakage of the filter while it is being distributed, or when mounted and/or in use.

Description: FILED OF THE INVENTION The present invention relates to an engine intake-air filter apparatus. BACKGROUND OF THE INVENTION An engine intake-air cleaner apparatus is incorporated in an intake-air system of an engine in order to remove dust from intake-air and to reduce noise of intake-air. There exists a conventional air-cleaner apparatus adapted an air-filter apparatus to be removably fitted in an air-cleaner casing which is attached to an air-cleaner conduit. In this air-filter apparatus, a filter support member such as a net or the like is stretched in a filter attaching frame of an outer structural member which is held in the air-filter casing so as to support an air-cleaner filter with the use of the filter support member. There exists another air-filter apparatus which is attached directly to the intake-air port of an air cleaner casing. In this air-filter apparatus, a filter support member such as an inner net is stretched in a filter attaching frame of an outer structural member such as a funnel attached to an air-cleaner conduit, and an air-cleaner filter is supported with the use of the filter support member. In conventional air-filter apparatuses for an air-cleaner apparatus, although the filter is held by any means in the filter attaching frame of the outer frame structure member, the filter is merely set and held on the filter support member. Further, in the conventional air-filter apparatuses, the filter support member is generally formed of hard metal materials such as stainless steel wires or a perforated stainless steel sheet. JP-A-06272630 reveals an air cleaner filter comprising layers of filter elements disposed like a semi-sphere. The marginal edges of the filter elements are integrated to hold the semi-sperical shape, and the inner most layer may have 3-dimensional cuts. One example of conventional air-cleaner apparatuses will be hereinbelow explained with reference to Fig. 5 illustrating an air-filter apparatus 1 attached directly to the intake-air port of an air-cleaner apparatus in which a flared opening of a funnel 2 is covered with an inner net 3 and an outer net 4 between which an air-cleaner filter 5 having a two-layer structure is laid. The end parts of the inner net 3 are fixed to a flat part 6 of a funnel 2 while the end parts of the outer net 4 are removably secured to the end parts of the flat part 6 . Further, each of these inner and outer nets 3, 4 is originally a rectangular net which is formed into a substantially semi-spherical shape. Further, an air-cleaner filter 5 is a wet-type filter which is impregnated with oil (having a coefficient of viscosity of 3 to 5 pa.s) in order to enhance the dust collecting effect. However, in the air-filter apparatus 1 shown in Fig. 5 , the inner net 3 and the outer net 4 are laid respectively over the front and rear surfaces of the filter 5 , and accordingly, the intake-air opening area of the filter 5 is decreased so that the intake-air resistance possibly increases. In the conventional filter apparatus 1 , it is desirable to increase the flared opening of the funnel 2 in order to enhance the intake-air efficiency. However, if the size of the funnel is increased, the air-filter apparatus 1 requires a larger-size which is unpreferable for an air-filter apparatus adapted to be located in a limited space. Further, since the outer net 4 is a rectangular net which is formed into a substantially spherical shape, a curved part thereof is deformed, that is, its rectangular shape is deformed into a diamond-like shape or the like, and more specifically, each of the comers thereof is greatly deformed. This deformation hinders the flow of the intake-air, and accordingly, the intake-air efficiency is possibly lowered. Further, since the air-cleaner filter 5 is impregnated with oil having a small coefficient of viscosity, in case the size of pores in porous resin (such as polyurethane resin) which forms the air-cleaner filter is large, the impregnation of oil would be insufficient. Accordingly, the air-cleaner filter 5 is made of porous resin which is impregnated with the oil, resulting in increased flow-passage resistance of the air-cleaner filter 5 . In view of this point, the intake-air efficiency is lowered. An object of the present invention is to provide an air-cleaner apparatus which can enhance the intake-air efficiency without increasing the size of the air-cleaner apparatus. According to the present invention there is provided an air-cleaner apparatus wherein a flared opening of a funnel is covered with an inner frame and an outer frame between which a filter is interposed, comprising a lip part that is integrally planted on the inner peripheral surface of the flared opening of the above-mentioned funnel, opposing the flowing direction of the intake-air such that a negative pressure area is induced upstream of and below said lip part. The inner frame may be composed of a top part which extends to the center part of the flared opening of the funnel, and a plurality of frame bars radially extend from the top part. Preferably the outer frame is formed of a honeycomb-like net. The filter may be formed of porous resin having a large pore size impregnated with an adhesive having a high coefficient of viscosity. The present invention offers the following three effects: (1) Since the lip part is planted on the inner peripheral surface of the flared opening of the funnel, a negative pressure area is induced upstream of and below the lip part due to the stream of intake-air so that the flow rate of intake-air flowing into the funnel from the outer peripheral part of the flared opening of the funnel is heightened, and as a result, the volume of intake-air is increased. Thereby it is possible to enhance the intake-air efficiency without the size of the air-cleaner apparatus being increased by increasing the size of the funnel. (2) Since the outer frame is formed of a honeycomb-like net in a substantially semi-spherical shape, the honeycomb-like deformation is equally divided into six portions, and accordingly, the deformation at each corner of the honeycomb-like (hexagonal) filter is less than that of the conventional rectangular shape net. Accordingly, it is possible to enhance the intake-air efficiency without hindering the stream of intake-air. (3) Since the filter is formed of porous resin impregnated with an adhesive having a high coefficient of viscosity, the adhesive can enhance the dust collecting efficiency, and since the pore size of the porous resin is large, the flow passage resistance of the filter becomes small, therefore, it is possible to enhance the intake-air efficiency. BRIEF DESCRIPTION OF THE DRAWINGS: Figs. 1A and 1B show an embodiment of an air-cleaner apparatus according to the present invention, in which Fig. 1A is a side sectional view illustrating the air-cleaner apparatus, and Fig.1B is a plan view illustrating the air-cleaner apparatus from which a filter and an outer net are eliminated; Figs. 2A and 2B show an external appearance of the air-cleaner apparatus shown in Figs. 1A and 1B , in which Fig. 2A is a side view illustrating the air-cleaner apparatus, and Fig. 2B is a plan view illustrating the air-cleaner apparatus; Figs. 3A and 3B show a funnel in the air-cleaner apparatus shown in Figs. 1A and 1B , in which Fig. 3A is a side sectional view illustrating the funnel, and Fig. 3B a plan view illustrating the funnel; Figs. 4A and 4B show an inner frame in the air-cleaner apparatus shown in Figs.1A and 1B , in which Fig. 4A is a side sectional view illustrating the inner frame, and Fig. 4B is a plan view illustrating the inner frame; and Fig. 5 is a side view illustrating a left half part of a conventional air-cleaner apparatus. Referring to Figs. 1 to 4 , an air-cleaner apparatus 19 is composed of a funnel 26 , an inner frame 27 , an outer net 28 as an outer frame and a filter 29 , for removing dust from air introduced into an engine and enhancing the intake-air efficiency. The funnel 26 and the inner frame 27 are made of synthetic resin such as plastic while the outer net 28 is made of metal such as iron, and the filter 29 is made of porous resin. As shown in Figs. 1 and 3 , the funnel 26 has a duct part 30 which is connected thereto with a flared opening 31 whose diameter is gradually increased, and a flat part 32 is connected to the flared opening 31 . Further, a lip part 33 is integrally planted on the inner peripheral surface of the flared opening 31 . The duct part 30 can be connected to an air flow meter 20 . Further, an engaging stepped part 34 is formed at the outer periphery of the flat part 32 . An engaging end (which will be explained later) of the inner frame 27 can be engaged with the engaging stepped part 34 . The lip part 33 is formed opposing the stream A of air flowing into the air-cleaner apparatus 19 , and this stream A of air induces a negative pressure area B between the lip part 33 and the flat part 32 . Under the effect of this negative pressure area B, the flow rate of air flowing into the funnel 26 along a flat part 37 (which will be explained hereinbelow) of the inner frame 27 can be increased. As shown in Figs. 1 and 4 , the inner frame 27 is composed of a top part 35 extending from the flared opening part 31 of the funnel 26 to the center part of the duct part 30 , frame bars 36 with which the lip part 33 of the funnel 26 is covered, and which radially extend from the top part 35 , and a flat part 37 extend radially outward from the frame bars 36 , orthogonal to the top part 35 . The frame bars 36 have a stream line cross-sectional shape. The top part 35 and the frame bars 36 smooth the stream A of air flowing into the funnel 26 . The flat part 37 is engaged at its inner peripheral edge with an engaging edge 38 so as to be engaged with the engaging stepped part 34 of the funnel 26 , and accordingly, the inner frame 27 is fitted to the funnel 26 . In this assembled condition, the flat part 37 of the inner frame 27 is flush with the flat part 32 of the funnel 26 so as to define a flat surface, whereby it is possible to smooth the stream of air flowing along the flat parts 37, 32 . The flat part 37 of the inner frame 27 is formed at its outer surface with an engaging ridge 39 . This engaging ridge 39 has a triangular cross-sectional shape and is adapted to stick into the end surface 40 of the filter 29 so as to restrain the filter 29 from being elastically deformed, and to prevent the end surface 40 of the filter 29 from floating up from the outer surface of the flat part 37 . A screw fitting part 41 is embedded in the top part 35 , as shown in Fig. 1A and 4B, and a net retaining bolt 42 can be tightened into the screw fitting part 41 . The net retaining bolt 42 has a large diameter head part 42A by which the outer net 28 is integrally incorporated with the top part 35 of the inner frame 27 . The outer net 28 is formed of a honeycomb-like (hexagonal) net in a substantially semi-spherical shape. With this honeycomb-like net, deformation in the curved part 28A of the outer net 28 is equally divided into six portions at comer parts of the hexagon, and accordingly, the degree of the deformation at each corner becomes smaller than that of a rectangular net. As shown in Fig. 1A , the filter 29 is composed of an outer filter 43 and an inner filter 44 which are joined together in a two layer structure, and which are formed of polyurethane resin. That is, the outer filter 43 is made of polyurethane resin having a large coarse pore size, but the inner filter 44 is made of polyurethane resin having an intermediate pore size. The outer filter 43 and the inner filter 44 are bonded together by heating and melting their bonding surfaces (which is the so-called lamination). The outer filter 43 and the inner filter 44 are impregnated with a highly viscous adhesive (which is not shown) in order to enhance the dust collecting effect. For example, chlorinated paraffin is used as the highly viscous adhesive, preferably having a coefficient of viscosity which is higher than about 100 pa.s and lower than about 350 pa.s. The fibers of the outer filter 43 and the inner filter 44 are swollen and softened with the use of a solvent (such as methylene chloride or thinner), and thereafter, the softened fibers are impregnated with the highly viscous adhesive. Next, explanation will be hereinbelow made of operation and effects. Air flowing from the outer periphery of the air-cleaner apparatus 19 and passing through the meshes of the outer net 28 , passes through the filter 29 and flows along the top part 35 of the inner frame 27 and the frame bars 36 , and then flows into the duct part 30 along the lip part 33 and the flared opening 31 of the funnel 26 . During passing through the filter 29 , dust is removed from the air. With the above-mentioned embodiment, since the lip part 33 is planted on the inner peripheral surface of the flared opening 31 of the funnel 26 , the stream A of air induces the negative pressure area B between the lip part 33 of the funnel 26 and the flat part 32 so as to increase the flow rate of air flowing into the duct part 30 of the funnel 26 from the outer side of the flat part 37 of the inner frame 27 , whereby it is possible to increase the volume of intake-air. Thus, it is possible to enhance the intake-air efficiency without the size of the air-cleaner apparatus 29 being increased by increasing the size of the funnel 26 . Further, since the inner frame 27 is composed of the top part 35 extending to the center part of the funnel 26 , and since the top part 35 is composed of a plurality of the frame bars 36 radially extending from the top part 35 and having a stream line cross-sectional shape, the stream A of air flowing into the funnel 26 can be smoothed so as to reduce the flow passage resistance, whereby it is possible to enhance the intake-air efficiency. Further, since the flat part 37 of the inner frame 27 is flush with the flat part 32 of the funnel 26 in the assembled condition between the funnel 26 and the inner frame 27 , the stream of air flowing through the flat parts 32, 37 is not hindered, whereby it is possible to further enhance the intake-air efficiency. Since the outer net 28 is formed of a honeycomb-like net in a substantially semi-spherical shape, deformation of the honeycomb net occurring in the curved part 28A is equally divided into 6 portions so that deformation at each corner of the honeycomb cell can be made smaller than that of a rectangular cell. Accordingly, it is possible to prevent the stream A of intake-air from being hindered by the outer net 28 , and in view of this point, it is possible to further enhance the intake-air efficiency. Further, since the filter 29 is made of porous polyurethane resin, and since the filter 29 is impregnated with the highly viscous adhesive, the dust collecting effect can be enhanced by the highly viscous adhesive. Simultaneously, since the filter 29 can be impregnated with the highly viscous adhesive even though it has a large pore size, the flow passage resistance of the filter 29 becomes small, in comparison with such a case that the filter 29 is made of porous polyurethane resin having a small pore size. In addition, since the engaging ridge 39 is formed on the flat part 37 of the inner frame 27 and is adapted to lock the end surface 40 of the filter 29 , it is possible to prevent the end surface 40 from floating up, whereby it is possible to prevent lowering the dust collecting effect of the filter 19 . As mentioned above, the air filer apparatus for engine intake-air, according to the present invention, can enhance both dust collecting effect and intake-air efficiency of the air filter apparatus.

Claims: An air cleaner apparatus comprising an inner frame (27) and an outer frame (28) with which a flared opening (31) of a funnel (26) is covered, and a filter (29) interposed between said frames, wherein a lip part (33) is integrally planted on the inner peripheral surface of said flared opening (31) of said funnel (26), being opposed to an air stream direction such that a negative pressure area (B) is induced upstream of and below said lip part (33). An air-cleaner apparatus as set forth in claim 1, wherein the inner frame (27) is composed of a top part (35) extending toward a center of said flared opening (31) of said funnel (26), and a plurality of frame bars (36) extending radially from said top part (35). An air-cleaner apparatus as set forth in claim 1 or 2, wherein said outer frame is formed of a honeycomb-like net (28). An air-cleaner apparatus as set forth in any one of claims 1 to 3, wherein said filter (29) is made of a porous resin having a large pore size and impregnated with a highly viscous adhesive. An air-cleaner apparatus as set forth in any one of claims 1 to 4, wherein a flat part (32) is connected to the flared opening (31) below said lip part (33) and said negative pressure area (13) is induced between said lip part (33) and said flat part (32). An air-cleaner apparatus as set forth in claims 2 and 5, wherein said inner frame (27) comprises a flat part (37) extending radially outwardly from said frame bars (36) and wherein said flat part (37) is flush with said flat part (32) of said funnel (26) in the assembled condition. An air-cleaner apparatus as set forth in claim 6, wherein said flat part (32) of said funnel (26) comprises at its outer periphery a stepped portion (34) and said flat part (37) of said inner frame (27) comprises at its inner periphery an engaging step (38) engaged with said stepped portion in the assembled condition.

Inventors: KATTA MASAHIKO, KATTA, MASAHIKO
Applicants: HKS CO LTD, HKS CO., LTD.
Application year: 1995
Main classification: F02M35
IPC codes: F02M35, B01D46