RESIN AIR INTAKE SYSTEM PROVIDED WITH INTAKE CONTROL VALVE

Abstract: The objective is to provide a resin air intake system provided with an intake control valve which permits simplifying the mold structure and maintaining axis center precision. In an air intake manifold with air intake passages (13) and (14) are fabricated to be opened and provided with an intake control valve (31) supported by a shaft (30) having an axis in the direction perpendicular to the axes of the openings (16), the air intake manifold is molded from a resin comprising at least an air intake manifold proper (10) and an air intake manifold cluster (20) which have split faces for the two, the split face of the air intake manifold proper (10) is provided with groove (18) in a direction perpendicular to the axes of the openings (16), bearings (32) which slidably support shaft (30) are mounted to be in the grooves (19), and a projection which projects from the split face of the air intake manifold cluster is brought into contact with the bearings (32).

Description: TITLE RESIN AIR INTAKE SYSTEM PROVIDED WITH INTAKE CONTROL VALVE BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine air intake system, particularly a resin air intake system provided with an intake control valve, designed to make the air intake system be provided with an air intake control valve of a resin. 2. Description of Related Art Requirements for higher performance engines in recent years have resulted in using a variety of systems for air intake systems. There is known a so-called variable air intake system to improve both the engine torque in the medium to low speed range and to improve output in the high speed region. These try to increase the engine fueling efficiency by varying the essential air intake type lengths or capacity of the air intake system according to the engine operating conditions, so as to make effective use of inertial and resonance actions under a given situation. In order to change the air intake tube length or capacity, such a variable air intake system equips the air intake constituting part, such as an air intake manifold, with air intake passages open to be connected to each combustion chamber of an engine with intake control valves rotatably, which are supported by a shaft having an axis in the direction perpendicular to the axes of the openings. Driving this shaft with an external actuator is designed to control the opening and closing of the intake control valve. There is known a lean combustion engine for improved engine fuel consumption rate for energy saving, in which its air intake manifold is provided with a plurality of air intake passages per cylinder, and controlling the opening and closing of an intake control valve provided for one of the air intake passages is designed to give an air intake with a swirl within the designated operating range. In general, such an air intake manifold is cast from a metal such as aluminum and bearing holes to support the above shaft rotatably are drilled by machining after casting. SUMMARY OF THE INVENTION From the standpoint of energy saving, requests for reducing engine weight are still intense, for which attempts and proposals have been made to make an engine air intake system from a resin. Among these approaches, there are examples in which part of an air intake system, such as a simple design air duct and an intake manifold with no movable parts have already been made of a resin, but there is yet no example in which a resin is used to make an air intake system provided with the above intake control valve, particularly in an air intake manifold. Having no such example may be rationalized in terms of the insufficient development of materials which can possess the heat resistance in a high temperature engine compartment and have strength enough to endure the shaking resulting from engine vibration. Furthermore, another lack of such example may be due to the fact that an air intake manifold provided with an intake control valve, or the like, is too complicated in configuration to allow an ease of fabricating the molds or cores therefore. In particular, if an intake control valve, and the like, are provided, there is a need for having a bearing opening which rotatably supports the shaft for the intake control valve, but drilling such an opening by machining after molding from a resin will not allow taking advantage of molding by a one-shot molding operation, while fabricating it by molding alone will aggravate the difficulty in making such a mold for it. In addition, when a plurality of intake passages are arrayed in parallel, machining such a bearing hole opening incurs extreme difficulty in achieving a precision axis center in the case of the resin. Therefore, the problem has been that since the machining of the bearing opening is difficult, supporting the shaft while warranting the sealability of each air intake passage is also difficult. It is an objective of this invention to solve the previous problems and to provide a resin air intake system provided with an intake control valve which permits simplifying the mold structure and maintaining the axis center precision. It is another objective of this invention to provide a resin air intake system provided with an intake control valve which can easily assure the sealability of each air intake passage or the sealability of the shaft support. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is an exploded oblique view showing Example 1. Figure 2 is a cross sectional view showing the way Example 1 is assembled. Figure 3 is a semi-cross sectional view along III-III line cut of Figure 1. Figure 4 is a partial cross sectional view along IV-IV line of Figure 1. Figure 5 is a partial cross sectional view of a carrier plate along V- V line of Figure 1. Figure 6 is a partial plan view of a carrier plate. Figure 7 is an exploded oblique view showing Example 2 of this invention with a different point of viewing for the supplementary air intake manifold 120 to aid comprehension. Figure 8 is an exploded oblique view showing Example 3 of this invention. Figure 9 is an exploded oblique view showing Example 4 of this invention. DETAH.ED DESCRffTION In order to achieve such objectives, one embodiment of this invention comprises is a resin air intake system provided with an intake control valve characterized in that in an air intake system comprising an air intake constituting part with an air intake passage open to be connected through an engine combustion chamber which part is provided with intake control valves supported by a shaft having an axis in the direction perpendicular to the axes of the openings, wherein said intake constituting part is molded from at least a first and second part having a split face between the two; providing said split face of said first part with a groove in the direction perpendicular to the axes of said openings; fitting into said groove a bearing part which slidably supports said shaft; and bringing a projection which projects from said split face of the second part into said bearing part. A preferred embodiment of this invention is that the above groove has a U-shaped cross section and is provided with notched grooves in which the side edge of said bearings are engaged. A further preferred embodiment of this invention comprises a resin air intake system provided with an intake control valve wherein said first and second parts make up an intake manifold provided with a plurality of air intake passages built in parallel; said shaft is one common shaft which supports the intake control valves corresponding to the plurality of air intake passages; and said bearing parts are mounted with at least one on each side of each air intake passage. Another preferred embodiment of this invention is characterized in that a resin air intake system is provided with an intake control valve in which said first and second parts make up a throttle body and said intake control valve is a throttle valve. Another embodiment of this invention comprises a resin air intake system provided with an intake control valve characterized in that an air intake system comprises an air intake constituting part with an air intake passage open to be connected through an engine combustion chamber which part is provided with an intake control valve supported by a shaft having an axis in the direction perpendicular to the axes of the openings, wherein said intake constituting part is molded from at least a first, second, and third part having a split face between the two; providing said split face of said first part with grooves in the direction perpendicular to the axes of said openings; fitting into said grooves bearing parts which slidably support said shaft; and bringing a projection which projects from a front side split face of said third part into said bearings at the same time bringing the back side split face into the split face of said second part. A preferred embodiment of this invention is characterized by a resin air intake system provided with an intake control valve except the third part is a plate having a gasket for sealing in the form of covering said air intake passage for each of the said front side and back side split face. Operation According to one embodiment of this invention, the air intake constituting part with its air passage through an engine compartment being formed open is molded from at least a first and a second resin part which has a split face between the two and the split face of the first part is provided with a groove in the direction perpendicular to the axes ot the openings. A bearing which slidably supports a shaft provided with an intake control valve is made to fit into the groove and the projection which projects from the split face of the second part is brought into contact with the bearing. The shaft is held within the groove provided on the split face of the first part, so that the mold structure is simplified and axis center precision can also be maintained. Since the bearing parts are made to fit in the groove and the projection is brought into contact with the bearings, this readily assures the sealability of the shaft support. According to a preferred embodiment of this invention, said groove has a U-shaped cross section and is provided with notched grooves within which the side edge of said bearings fit, so that there is no revolution of the bearing due to the revolution of the shaft or shifting in the thrust direction to give further better sealability. According to further improved embodiment, said first and second parts make up an air intake manifold provided with a plurality of air intake passages fabricated in parallel and the shaft is a one common shaft that supports the air intake control valves corresponding to the plurality of air passages and at least one of said bearing is mounted on each side of each air intake passage; hence, the mold structure as described above can be simplified and its axis center precision can also be maintained. Furthermore, the sealability of the shaft support, that is, the sealability between each air intake passage can also be readily assured. According to another preferred embodiment of this invention in which the above first and second parts make up a throttle body and said air intake control valve is a throttle valve, there is no need to mold the groove body independently, thereby simplifying the mold structure. According to another embodiment of this invention, the air intake constituting part with its air intake passage through an engine compartment chamber is fabricated open and is molded from at least a first, second, and third part having a split face therebetween and the split face of the first part is provided with a groove in a direction perpendicular to the axes of the openings. A bearing which supports slidably a shaft provided with an air intake control valve is made to fit into the above groove; the projection which projects from the front side split face of the third part is brought into contact with the bearing, at the same time bringing the backside split face into contact with the split face of the second part. Thus, the shaft can be held in the groove provided on the split face of the first part, so that the mold structure can be simplified and the bearing center precision can also be maintained. Furthermore, since the bearing is made to fit into the groove and the projection which projects from the front side split face of the third part is brought into contact with the bearing so that the sealability of the shaft support can also be readily assured. Furthermore, according to a preferred embodiment, the third part is a plate provided with a gasket for sealing in the form of surrounding the air intake passage for each of the front side split face and back side split face so ύiat die sealability between each air intake passage can also be assured, in addition, making it easy to fabricate the third part. The mold structure can also be further simplified. EXAMPLES Preferred examples of this invention are described specifically based on die examples described by the attached drawings. Each of these examples are meant to illustrate the invention without limiting the scope thereof. In fact, it would be clear to those skilled in the art that a variety of amendments and modifications of diis invention can be made without deviating from the scope, that is, the spirit of this invention. For example, any features which are illustrated or described as a part of Example 1 can be other examples to create further examples. Throughout me described explanations and drawings, identical functional sites use comparable numerals. Example 1 of this invention is described by referring to Figures 1-6. Example 1 An application of this invention to a variable air intake system which makes use of an air intake inertia action. In the figure, 10 is an air intake manifold proper; 20 is an air intake manifold cluster, each as a whole is fabricated from a glass fiber reinforced thermoplastic resin. The thermoplastic resin used here in terms of heat resistance and strength-wise adaptability is preferably polyamide, polyester, or polyphthalamide, or the like. Air intake manifold proper 10 is provided at both ends thereof first and second attaching flanges 11 and 12. Furthermore, in diis example, for each cylinder of die engine (not illustrated) a short lengdi air intake passage 13 and a long lengdi second air intake passage 14 are provided. These first and second air intake passages are confluenced mid-way and they open as a common opening 15 in the first attaching flange 11. In the second attaching flange 12, each opens as a first and second opening 16 and 17. For diis example, which is an air intake manifold for a four cylinder engine, such first and second openings 16 and 17 are paired and arrayed as four pairs in parallel. The first and second air passages 13 and 14 can be molded using a core by a "lost core" process. In the molding operation, the edge face of the second flange 12, that is, the split face, is provided widi a U-shaped cross sectional groove 18 in the direction perpendicular to the axes of the first openings 16. Groove 18, so as to permit the shaft to be described later, to extend outwardly has one end opened to die outside of die second flange 12. Groove 18 is provided widi at least one notched slot 19 on each side of each of die four first openings 16. In the illustrated example, me length between the opening 16 and 16 corresponding to die second or iird cylinder is too long so mat the two notched grooves 19 and 19 are provided. Notched grooves 19 have a broader designated wid i and deeper U-shaped grooves relative to d e U- shaped cross sectional groove 18 and iey have the designated diickness. The air intake manifold cluster is provided widi a flange 21 in a shape corresponding to die second flange 12 of die air intake manifold proper, 10, and die flange 21 is provided widi openings 22 in a form which encompasses the first and second openings 16 and 17, arrayed as four pairs as described above. The air intake manifold cluster 20 is connected d rough its integrated duct 23 to an upstream throtde body (not illustrated). Here, the above air intake manifold 10 makes up the first part of the air intake constituting part and die air intake manifold cluster 20 constitutes die second part of die air intake constituting part and die edge faces of the flanges 12 and 21 are split faces. 30 is a shaft having an axis in d e direction perpendicular to die axes of die openings 16, which in this example is a common single metal shaft. A common single shaft may be made by connecting a multiple number of metal shafts obtained by machining me engaging sections in a preliminary step. The designated bearing chamfer of said shaft 30, as is well known, supports butterfly type air intake control valves 31 corresponding to the number of openings 16 so as to be pivoted. Instead of diis attachment, a resin valve may be molded onto die shaft. Shaft 30 is provided wid bearings 32 which slidably support shaft 30 at a position corresponding to die above notched grooves 19. Bearings 32 engage widi the notched grooves 19 and are wide and diick enough to constitute a contact seal or a labyrinύi seal; and dieir upper ends are made into a flat U-shape. These are made of a resin or metal which has excellent sliding properties, preferably a poly amide or polyimide if a resin is used or a bearing metal if a metal is used. 40 is a carrier plate as a third part and is made of a resin similar to diat of the first and second parts. The carrier plate 40 has a contour corresponding to each of die flanges 12 and 21 of d e above air intake manifold proper 10 and air intake manifold cluster 20, respectively, and is interposed between die two flanges. Openings 41 and 42 are provided corresponding to me above openings 16 and 17 of me first and second parts. The front side of carrier plate 40 (the side opposite to diat illustrated in Figure (1)) has die projections 43 projecting from the split face (see Figures 3 and 4) widi die projections having a shape which is brought into contact with the upper end of bearing 32 corresponding to die widdi and diickness of the above notched slot 19. The front and back sides of die carrier plate 40 are provided widi annular grooves 44 and 45 in die shape of surrounding openings 41 and 42 corresponding to d e openings 16 and 17 of die above first and second parts. However, the annular groove 44 on die front side surrounding opening 41 is an exception made discontinuous by projection 43 (see Figure 3). The annular grooves 44 and 45 on die front side are connected to d e annular grooves 44 and 45 on die back side tiirough their bases via a continuous opening 46 provided at certain intervals. The annular grooves 44 and 45 on die front and back sides are provided widi rubber and like gaskets 47 and 48 by casting so as to project from the front and die back sides in the state of non-compressed condition. Incidentally, die front and back side gaskets 47 and 48 are connected via die above connecting opening 46 and are prevented from dropping off from carrier plate 40 after casting. 50 is an actuator supported by support bracket 51 , integrally molded to me air intake manifold proper 10, which drives me revolving shaft 30. Support bracket 51 may be formed separately. The actuator is a pressure response type diaphragm actuator or an electrical motor. In me above example, die air intake manifold proper 10, air intake manifold cluster 20, and carrier plate 40 are molded from die resin in the above configuration and men assembled widi a sub-assembled air intake control value 31. That is, the shaft 30 is placed in the groove 18 while the bearings 32 which support slidably die shaft 30 are engaged in the notched slot 19; and die carrier plate 40 is mounted on the flange 12. The flange 21 of d e air intake manifold cluster 20 is mounted on die carrier plate 40 and die flanges 12 and 21 are fastened by bolts (non-illustrated) widi d e carrier plate 40 interposed dierebetween. As tightening progresses, die gaskets 47 and 48 of carrier plate 40 are compressed and deformed so as to bring die split faces to come in contact with each other. In this case, projection 43 which projects from the front side split face of die carrier plate 40 is engaged in die top of notch slot 19, coming in contact with die top flat face of die bearings 32, tiiereby aligning to secure die bearings 32 at me designated positions. A dimensional relationship is established between die bearings 32 and notched grooves 19 so as not to cause shaft 30 to substantially come in contact widi slot 18, which is preferred for the maintenance of die shaft 30 at d e center and prevention of wear. Lastiy, die actuator 50 is connected to shaft 30. In die variable air intake system in d is example, as the shaft 30 rotates, sliding against bearings 32 when driven by die actuator 50 in me low to medium revolution range of an engine, and die control valves 31 supported by shaft 30 close d e first air intake passages 13 to introduce air intake to the engine only dirough the lengd y second air intake passages. W en a high speed revolution range is reached, die short lengdi first air intake passages 13 are opened by die air intake control valves 31 to allow air intake through bo i die first and second air intake passages 13 and 14. Thus, it is essential diat die air passage lengdi can be switched according to die engine revolution region to a lengdi suitable for obtaining a inertial- supercharging effect, thus enhancing the charge efficiency. Any leakage among die first air intake passages 13 corresponding to each cylinder when die air intake control valves are in a closed position, is prevented by having the U-shaped bearings 32 engaging with die notched slot 19 widi dieir upper ends being brought into contact wid die projection 43 of die carrier plate 40, as well as by the gasket 47 between die split faces. A similar example of this invention is explained referring to Figure 7. This example is an application of this invention to die air intake system of a lean combustion engine. In me figure, 110 is an air intake manifold proper and 120 is a supplemental air intake manifold. Bod , as entireties, are molded, as in the case of die above example, of a glass fiber reinforced diermoplastic resin. In diis example, the upstream section of the air intake manifold proper 110 is integrally molded as a cluster section widi a surge tank 111, with die bottom ends provided widi attaching flange 112. Each cylinder of e engine (not illustrated) is provided widi about equal lengdis of first air intake passage 113 and second air intake passage 114. These first and second air intake passages come to confluence midway and open to surge tank 111 at a common opening 115. Attaching flange 112 is opened by way of openings 116 and 117 for the first and second parts. Since diis example is for an air intake manifold for a four cylinder engine four pairs of such first and second openings 116 and 117 are arrayed in a series. The edge face of die attaching flange 112, diat is the split face is provided widi a U-cross-sectional shaped groove 118 which runs in a direction perpendicular to die axes of openings 116. The groove 118 has one end opened to die outside of attaching flange 112. Groove 118 is provided wid at least one notched slot 119 for each side of die 8 first and second openings 116 and 117. Notched slot 119, as in the above example, has a designated broader widdi and deeper U-shaped cross- section compared to die U-cross-sectional shaped groove 118 and has a designated diickness. In die supplementary air intake manifold 120, at d e upper end an attaching flange 121 is provided in a shape corresponding to die attaching flange 112 of die air intake manifold proper 110; said flange 121 is provided widi die first and second openings 122 and 123 in a shape corresponding to d e openings 116 and 117 of d e four paired first and second parts, as well as the first and second supplementary air intake passages (not illustrated) connected to d e openings 122 and 123. At d e bottom is provided an attaching flange 124 corresponding to a similar engine cylinder head, and so on. In diis example, the aforementioned air intake manifold proper 110 makes up me first part of me air intake constituting part and d e supplementary air intake manifold 120 makes up me second part of die air intake constituting part widi dieir flanges 112 and 121 edges faces becoming split faces. 130 is a shaft having an axis in die direction perpendicular to d ose of openings 116 and is a common single metal shaft in diis example. The designated bearing chamfer of the shaft 130 as is well known, supports butterfly inlet control valves 131 in a number corresponding to d e numbers and positions of die first openings 116. Shaft 130 is provided wid bearing 132 which slidably supports shaft 130 at a position corresponding to die above notched slot 119. A bearing 132, as in die previous example, has enough widd , diickness, and material so as to be engaged widi notched slot 119 to make up a labyrindi seal U-shaped widi a flat top end. 140 is a carrier plate as a third part and is molded from a resin similar to that of die first and second parts. Carrier plate 140 has a contour corresponding to each of die flanges 112 and 121 of die above are intake manifold proper 110 and supplementary air intake 120 and is interposed between diese two flanges. It has openings 141 and 142 corresponding to die openings 116 and 117 of die first and second parts. The basic structure wi i a carrier at 140 is identical to die carrier plate 40 of die previous example except for different opening positions, and die like parts are explained using symbols with die symbols increased by 100 widi respect to die symbols used in illustrating Figures 3-6; Figures 3-6 should be referred to in following die description below. The front side of die carrier plate 140 (die side opposite to diat illustrated in Figure 7) is provided widi projection 143, projecting from the split face, die projection being in a shape which is brought into contact widi die upper end of die bearings 132 corresponding to die widdi and diickness of die above notched slot 119 (see Figures 3 and 4 of die previous example). The front and back sides of die carrier plate 140 are provided widi annular grooves 144 and 145 in a shape of surrounding each of die openings 141 and 142 corresponding to die openings 116 and 117 of die above first and second parts. This is so except for die fact that die annular groove 144 on die surface side surrounding die openings 141 is made discontinuous by projection 143 (see Figure 3). Annular grooves 144 and 145 on d e front side are made to be connected dirough dieir bottoms to the annular grooves 144 and 145 for die back side, respectively, dirough a connecting opening 146 provided at die designated intervals. Rubber, and die like, gaskets 147 and 148 are provided by casting to die annular grooves 144 and 145 of bodi die front and back sides, so as to project from the front and back sides, respectively, in a noncompressed state. Incidentally, die gaskets 147 and 148 for both d e front and back faces are connected dirough die above connecting openings 146 so as to prevent them from dropping off from the carrier plate 140 after casting. However, in this example, air intake manifold proper 110, supplementary air intake manifold 120, and a carrier plate 140 are first molded from a resin into die above configuration. This is followed by assembling with a sub-assembled air intake control valve 131. Shaft 130 is placed in groove 118 with die bearings 132 being engaged widi notched grooves 119, and die carrier plate 140 is attached to flange 112. The flange 121 of die supplementary air intake manifold 120 is dien attached to die carrier plate 140. Flanges 112 and 121 are fastened by bolts which are not illustrated, while carrier plate 140 is interposed dierebetween. As the fastening progresses, as in die previous example, gaskets 147 and 148 of die carrier plate 140 are compressed and deformed to bring die split faces to come into contact with each odier. Incidentally, in diis case projection 143 which projects from die surface side split face of carrier plate 140 fits in the top of notched grooves 119 to come in contact wid die edge flat face of bearing 132, thereby aligning bearing 132 to me designated positions to secure d e bearings 132. An actuator which is not illustrated is connected to d e shaft 130. In a lean combustion system in diis example, for example in a low to middle load region of an engine, die shaft 130 is driven by d e actuator to cause it to rotate, while sliding against bearings 132, when intake control valve 131 supported on shaft 130 closes die first air intake passage 113 to cause die air intake dirough d e engine to pass only via die second air intake passage 114. The second air passage 114 is connected to a floor port of the engine via die second supplementary air intake passage, so diat die mixed gas assumes a swirl, which is optimum for lean combustion in a combustion chamber. As the system reaches a high load region, d e first air inlet passage 113 is opened by die air inlet control valves 131, so as to permit air intake through bodi the first and second air intake passages 113 and 114. This results in a reduced air intake resistance to assure die high output. When die air intake control valves 113 are closed, any leakage between each air intake passage 113 and 114 is prevented because d e U- shaped bearings 132 are engaged widi notched grooves 119 near die shaft 130 and d e edge sections diereof are brought into contact widi die positions 143 of d e carrier plate 140, as well as by gaskets 147 and 148 between the split faces. The second example shows an example using a supplementary air intake manifold 120 to be attached to d e cylinder head, but die supplementary air intake manifold 120 is not always needed depending upon engine types. For example, without having a supplementary air intake manifold 120, air intake manifold proper 110 may be attached to die cylinder head via a carrier plate 140. In this case, the air intake manifold proper 110 makes up the first part of the air intake constituting part, and die carrier plate 140 makes up die second part. The diird example of this invention is described by referring to Figure 8. The diird example is an application of diis invention to a variable air intake system which makes use of an air resonance action. In the figure, 210 is die top side air inlet manifold and 220 is die bottom side air inlet manifold and bodi in dieir entirety are molded as in die previous examples of a glass fiber-reinforced diermoplastic resin. The top air intake manifold 210 has a half-split box shape widi its bottom periphery being provided widi a joining flange 211. Furthermore, in diis example, a barrier wall 212 which separates the half split box between die top and bottom is mounted in die center at a location about die same height as that of die joining flange 211 and die rest of die section is opened as openings 213 and 214 for the first and second parts. The bottom air intake manifold 220 also has a half split box shape, having on die top end a joining flange 221. Air inlet passages 223 and 224 corresponding to each cylinder of an engine (not illustrated) extend from the bottom of die half split box shape; diese air intake passages open as openings of die first and second attaching flanges 225 and 226. This example is for an air intake manifold for a V-type six cylinder engine, so diat the first and second attaching flanges 225 and 226 are arrayed right and left in parallel. In molding die top air intake manifold 210, a joining flange 211 and d e edged face of barrier wall 212, that is the split face, are provided widi a cross-sectional U-shaped groove 218 in a direction perpendicular to die axis of die first opening 213. The groove 218 has one end opened to die outside at die joining flange 211 so as to allow die shaft to be described later to be extended outwardly. Groove 218 is provided widi at least one notched slot 219 on bodi sides of die opening 213. Notched slot 219, as in die case of die previous examples, is a designated broader and deeper U- shaped slot compared to d e cross-sectional U-shaped groove 218, and has die designated diickness. For the top air intake manifold 210, duct 215 having an axis perpendicular to die axis of the second opening 214 is integrally molded widi its axis matching that of joining flange 211. The duct 215 is connected to an upstream dirotde body (not illustrated). Here, die aforementioned top air intake manifold 210 makes up die first part of the air intake constituting part and die bottom air intake manifold makes up die second part of die air intake constituting part and die edge surfaces of die joining flanges 211 and 221 and barrier wall 212 make split faces. 230 is a shaft having its axis in a direction perpendicular to diat of die opening 213. To said shaft 230 is attached by mold shaping a rectangular resin air intake control valve 231 conforming to the shape of opening 213. Shaft 230 is provided widi bearings 232 which slidably support die shaft 230 at the positions corresponding to die above notched grooves 219. The bearings 232, as in die previous examples, have a widdi and diickness enough to be engaged widi notched grooves 219 to make up a labyrinth seal widi die edge of d e bearing being made to a flat U-shape. It is made of a resin or metal with excellent sliding properties, preferably of polyimide or polyamide in die case of die resin and a bearing metal in the case of a metal. This example does not use die carrier plate used in die previously examples. The joining flange 221 of die bottom air intake manifold 220 is provided widi a projection (not shown in Figure 8) projecting from die split face, widi the projection being in a shape which is brought into contact with the top edge of the bearings 232 corresponding to die widdi and diickness of die above-mentioned notched grooves 19. Eid er joining flange 211 or 221 is provided with a groove, which groove is provided with a rubber, or die like, gasket similar to diat of die previous example. However, in diis example, after the top air intake manifold 210 and bottom air intake manifold 220 have been molded widi die resin in the above configuration, diey are assembled toged er with an assembly of the shaft 230 and air intake control valve 231. The shaft 231 is held in groove 218 while die bearings 232 are engaged widi die notched grooves 219 of die top air intake manifold 210 and then die bottom air intake manifold 220 is mounted. In diis case, die projection which projects from the split face of d e bottom air intake manifold engages widi die edge of d e notched grooves 219 to come into contact with d e flat end faces of bearings 232, thereby aligning to secure the bearings 232 at the designated positions. An actuator which is not illustrated and die shaft 2 are connected to each odier. Thus, as die top and bottom side air intake manifolds 210 and 220 are joined togedier, a first surge chamber is formed on die bottom side of die barrier wall 212 and die second surge chamber on the top of the barrier wall 212. In die variable air intake system of this example, air intake control valve 231 is closed, for example, in an engine at a low-to-medium revolution region, thereby introducing an air intake to the engine via die first surge chamber of a small capacity. In an engine high revolution region, the first opening 213 is opened by die air intake control valve 231 driven by die actuator and supported by die shaft 230, wherein the second surge chamber absorbs any pulsation of die air intake. Therefore, the essential lengdis or capacities of the air intake system that affect the pulsating air intake are optimally switched according to die engine revolution region, diereby achieving improved torque over die entire revolution region. The fourth example of this invention is explained by referring to Figure 9. The fourth example is an application of diis invention to die dirotde body of an air intake system. In Figure 9, 310 is a first throtde body and 320 is a second dirotde body, bodi are molded as in die previous examples of a glass fiber reinforced diermoplastic resin. In diis example, the first throtde body 310 is integrally molded wid surge tank 315 and die second dirotde body wid air duct 325, connected to an air cleaner. The first and second dirotde bodies 310 and 320 are half split cylinders and have openings 312 and 322 (322 is not illustrated in die figure) along widi air intake passages and edges of die openings provided widi joining flanges 311 and 321. An air intake passage 316 corresponding to each cylinder of an engine (not illustrated) is mounted to extend from the surge tank 315. In molding the first throtde body 310, die edge face of the joining flange 311, diat is die split face is provided widi a cross-sectional U-shaped groove 318 in a direction perpendicular to die axis of die opening 312. The groove 318 has one end opened to d e outside at joining flange 311 in order to allow die shaft (o be described) o extend outwardly. The groove 318 is provided widi at least one notched slot 319 at each side of opening 312. Notched grooves 319, as widi die previous examples, have designated broader and deeper U-shaped grooves compared to the cross sectional U-shaped groove 318 and have die designated diickness. Here, die aforementioned first throtde body 310 makes up die first part of the air intake constituting part and second dirotde body 310 makes up die second part of die air intake constituting part where the edge faces of die joining flanges 311 and 321 are split faces. 330 is a shaft having an axis in a direction perpendicular to die axis of opening 312. Said shaft 230 has a hinged butterfly type dirotde valve 331 as an intake control valve. The shaft 330 is provided widi bearings 332 which support slidably die shaft 330 at positions corresponding to die above notched grooves 319. The bearings 332 as in die previous examples, have a widdi and diickness to engage widi die notched grooves 319 to constitute a labyrindi seal widi die edge shaped into a flat U-shape. It is made of a resin widi excellent sliding properties or a metal, preferably of polyimide or polyamide in die case of a resin and a bearing metal in the case of a metal. In diis example also, no carrier plate of Examples 1 or 2 is used; die joining flange 321 is provided widi a projection (not illustrated in Figure 9) projecting from a split face, the position corresponding to die widdi and diickness of die aforementioned notch grooves 319 and being brought into contact with d e upper end of die bearings 332. Joining flange 311 is provided widi a groove in a shape to surround opening 312 and said groove, as in die previous examples, is provided widi a rubber or like gasket 314. In this example, after the first dirotde body 310 and second hrotde body 320 have been molded from a resin into die above configuration, diey are assembled widi an assembly of shaft 330 and dirotde body 331, diat is, shaft 330 is held in groove 318 while die bearings 322 are engaged widi notched grooves 319 of die dirotde body 310 and die second dirotde body 320 is attached. In diis case, die projection projecting from die second dirotde body 320 split face is engaged in die edge of die notched grooves 319 and is brought into contact with die edge flat face of bearings 332, so as to align and secure die bearings 332 at the designated positions. A dirotde linkage which is not illustrated is linked to d e shaft 330. The throtde body is completed as die first and second dirotde bodies 310 and 320 are joined togedier. Advantageous Effect of the Invention As described above, according to one embodiment of diis invention, die air intake constituting part with its air passage through an engine compartment being formed open is molded from at least a first and a second resin part which has a split face between the two and die split face of the first part is provided widi a groove in a direction perpendicular to die axis of the opening; a bearing which slidably supports a shaft provided widi an intake control valve is made to fit into the groove and die projection which projects from the split face of the second part is brought into contact widi the bearing; me shaft is held within die groove provided on die split face of the first part, so that the mold structure is simplified and axis center precision can also be maintained. Therefore, this makes it easy to fabricate an air intake system provided widi an intake control valve from die resin. Furthermore, die bearing part is made to fit in die slot and die projection is brought into contact with the bearing, so as to readily assure die sealability of die shaft support. According to a preferred embodiment of diis invention, said groove has a U-shaped cross section and is provided widi a notched slot witiiin which the side edges of said bearing fit, so that there is no revolution of die bearing due to die revolution of die shaft or shifting in die dirust direction to further give better sealability. According to a further improved embodiment, said first and second parts make up an air intake manifold provided widi a plurality of air intake passages fabricated in parallel and die shaft is a common shaft diat supports die air intake control valves corresponding to die plurality of air passages and at least one of said bearings is mounted on each side of each air intake passage; hence, die mold structure as described above can be simplified and its axis center precision can also be maintained. Furthermore, die sealability of the shaft support, diat is, die sealability between each air intake passage can also be readily assured. According to anodier preferred embodiment of diis invention in which die above first and second parts make up a dirotde body and said air intake control valve is a dirotde valve, diere is no need to mold die groove body independendy, diereby simplifying me mold structure. According to anodier embodiment of diis invention, die air intake constituting part widi its air intake passage through an engine compartment chamber is fabricated open and is molded from at least a first, second, and diird part having a split face therebetween and die split face of the first part is provided widi a groove in a direction perpendicular to die axis of die opening; a bearing which supports slidably a shaft provided widi an air intake control valve is made to fit into die above groove; a projection which projects from the front side split face of die diird part is brought into contact widi die bearing, at die same time bringing die backside split face into contact widi die split face of the second part; dius, the shaft can be held in die groove provided on die split face of the first part, so that die mold structure can be simplified and die bearing center precision can also be maintained. Furthermore, since the bearing is made to fit into die slot and die projection which projects from the front side split face of the diird part is brought into contact with die bearing, die sealability of the shaft support can also be readily assured. Furthermore, according to a preferred embodiment, die diird part is a plate provided widi a gasket for sealing in die form of surrounding die air intake passages for both die front side split face and back side split face so diat die sealability between each air intake passage can also be assured, in addition, making it easy to fabricate the diird part. The mold structure can also be further simplified.

Claims: WHAT IS CLAIMED IS: 1. A resin air intake system provided widi an intake control valve characterized in diat in an air intake system comprising an air intake constituting part with an air intake passage open to be connected dirough an engine combustion chamber which part is provided widi an intake control valve supported by a shaft having an axis in die direction perpendicular to die axes of die openings, wherein said intake constituting part is molded from at least a first and second part having a split face between the two; providing said split face of said first part with a groove in die direction perpendicular to die axes of said openings; fitting into said groove a bearing part which slidably supports said shaft; and bringing a projection which projects from said split face of die second part into said bearing part. 2. A resin air intake system provided widi an intake control valve as set forth in Claim 1 in which said groove has a U-shaped cross section and is provided widi an notched groove for a side edge part of said bearing part to engage widi. 3. A resin air intake system provided widi an intake control valve as set forth in Claims 1 or 2 wherein said first and second parts make up an intake manifold provided widi a plurality of air intake passages built in parallel; said shaft is one common shaft which supports die intake control valves corresponding to die plurality of air intake passages; and said bearing parts are mounted widi at least one on each side of each air intake passage. 4. A resin air intake system provided widi an intake control valve as set forth in Claims 1 or 2 in which said first and second parts make up a dirotde body and said intake control valve is a throtde valve. 5. A resin air intake system provided widi an intake control valve characterized in diat in an air intake system comprising an air intake constimting part widi an air intake passage open to be connected dirough an engine combustion chamber, which part is provided wid an intake control valve supported by a shaft having an axis in die direction perpendicular to die axes of die openings, wherein said intake constituting part is molded from at least a first, second, and diird part having a split face between die two; providing said split face of said first part with a groove in die direction perpendicular to die axes of said openings; fitting into said groove a bearing part which slidably supports said shaft; and bringing a projection which projects from a front side split face of said diird part into said bearing at die same time bringing die back side split face into die split face of said second part. 6. A resin air intake system provided widi an intake control valve as set forth in Claim 5 except the diird part is a plate having a gasket for sealing in die form of covering said air intake passage for each of the said front side and back side split faces.

Inventors: FUJITA SUSUMU, FUJITA, SUSUMU
Applicants: DU PONT, FUJITA SUSUMU, E.I. DU PONT DE NEMOURS AND COMPANY, FUJITA, SUSUMU
Application year: 1996
Main classification: F02M35
IPC codes: F02B27, F02B31, F02D9, F02M35