JP5447331B2 - Hollow body manufacturing method, hollow body, flow rate measuring device manufacturing method, and flow rate measuring device - Google Patents

Description

  The present invention relates to a hollow body manufacturing method for obtaining a hollow body having a hollow portion formed therein, and a hollow body manufactured by this manufacturing method, and in particular, a hollow portion (bypass channel) is formed inside. The present invention relates to a method for manufacturing a flow rate measuring device (flow rate sensor module) including a hollow structure (hollow housing) and a flow rate sensor that measures the flow rate of a fluid flowing through a bypass flow path, and the flow rate measuring device.

[Conventional technology]
2. Description of the Related Art Conventionally, an air flow rate measuring device including a heating resistance type air flow meter (thermal air flow meter) that measures the flow rate of intake air sucked into a combustion chamber of an internal combustion engine mounted on an automobile is known ( For example, see Patent Documents 1 and 2).
The air flow meter described in Patent Document 1 (conventional example 1) is provided on the outer wall surface of the intake duct so that a flow sensor module (hereinafter referred to as a module) is located inside the intake duct that forms the intake passage of the internal combustion engine. Part of the module is fixed.
As shown in FIG. 12, this module incorporates a U-shaped bypass passage 101 and an electronic circuit 102 for the intake passage formed in the intake duct. The heating resistor and the temperature-sensitive resistor 103 are disposed in the bypass channel 101 and are fixed to the conductive supports 104 and 105 by welding or the like. Further, the module includes a base 112 having a drop-off preventing projection 111, a cover 113, and a housing 114, which are joined via an adhesive.

Further, the air flow meter described in Patent Document 2 (conventional example 2) is an assembly of a resin-molded housing 121 and cover, and a metal base, as shown in FIG. The bypass passage 125, which is inserted into the insertion hole 123 and in which the temperature measuring element 124, the heating resistor and the temperature sensitive resistor are arranged, is attached so as to be positioned in the intake passage 126 formed by the intake duct 122. Yes.
The housing 121 is made of plastic, and an electronic circuit board 127 and the like are insert-molded. Further, the electronic circuit board 127 is bonded and fixed to a metal base member (not shown) and is surrounded by the housing 121 so as to be protected by the housing 121. Further, the metal base member is integrated with the housing 121 by adhesive fixing to the housing 121.

Here, a forming method for forming a hollow body product (for example, an intake manifold or the like) having a hollow portion inside is known (see, for example, Patent Document 3).
As shown in FIG. 14, the technique described in Patent Document 3 (conventional example 3) has a pair of semi-hollow bodies 130 and 140 in primary molding so as to have joints 131 and 141 only at the outer peripheral edge thereof. In the method of forming the hollow body product by joining the joint portions 131 and 141 with the secondary molding resin, the joint ends 131 and 141 of the pair of semi-hollow bodies 130 and 140 are joined to the joint ends in the primary molding. Filling grooves 132 and 142 that are open on the side of the part and a plurality of communication holes 133 and 143 that communicate with the filling grooves 132 and 142 from the outside of the pair of semi-hollow bodies 130 and 140 are formed. In the secondary molding, the joining portion 131 of one half-hollow body 130 is held by the first holder 150, the joining portion 141 of the other half-hollow body 140 is held by the second holder 160, and the joining portions 131, 141 are retained. The ends of the two are kept in contact with each other.

  The second holder 160 is formed with a plurality of resin inlets 161 and a resin supply path 162. The molten resin is injected from the resin injection port 161 into the plurality of communication holes 133 and 143 and the filling grooves 132 and 142 to integrate the pair of semi-hollow bodies 130 and 140. Then, after the molten resin is cooled and solidified, the integrated hollow body product is taken out. A hollow body product is manufactured by the molding method as described above. In addition, convex portions 134 and 144 having the shape of rivet heads are formed outside the communication holes 133 and 143 of the pair of semi-hollow bodies 130 and 140.

[Conventional technical problems]
However, in the air flowmeters described in the conventional examples 1 and 2, there is a possibility that the adhesive protrudes into the bypass channels 101 and 125. As a result, there is a problem that the flow of air flowing through the bypass passages 101 and 125 is disturbed, and an error in measuring the air flow rate occurs.
Further, according to the technique of Conventional Example 3, the pair of semi-hollow bodies 130 and 140 are joined to the joining portions 131 and 141 provided only at the outer peripheral edge portions, and the molten resin is injected into the joined portions. Since the pair of semi-hollow bodies 130 and 140 are joined, there is a problem that the joining strength of the joined portions 131 and 141 of the obtained hollow body product is low. As a result, there is a problem that a gap is formed between the joining end surfaces of the joining parts 131 and 141 or a step is generated between the joining parts 131 and 141.

  Note that the bonding strength was increased by increasing the injection pressure or resin pressure when the molten resin was injected and filled in the secondary molding, and injection filling was performed by the secondary molding with the joint portions 131 and 141 of the pair of semi-hollow bodies 130 and 140. By improving the adhesion to the secondary molding resin, it can be increased to some extent. However, in order to increase the injection pressure or the resin pressure, it is necessary to make the mold for secondary molding strong. Further, when the injection pressure or the resin pressure is increased, there is a possibility that the molten resin leaks from between the joint end surfaces of the joint portions 131 and 141 to the bypass flow path side.

  In addition, when the technology of Conventional Example 3 is used for joining the housing (case) forming the air flow meter module and the cover, it is only possible to join the joint portion around the outer periphery of the housing and the joint portion around the outer periphery of the cover. In addition, the central partition walls that define the U-shaped bypass channel formed inside the housing and the cover must be joined together. When these two different joints are divided into two times by the secondary molding, there is a problem that the manufacturing time becomes long, leading to deterioration in productivity and an increase in manufacturing cost.

  The air flow meter is assembled by a plug-in method into a mounting hole formed at a predetermined position of the intake duct of the internal combustion engine. Therefore, as in the technique of the conventional example 3, rivets are formed on both end surfaces of the joint portions 131 and 141 of the pair of semi-hollow bodies 130 and 140 (protruding portions projecting outward from the cylindrical portion in the radial direction: protruding portions). When the convex portions 134 and 144 having the shape of the head are formed, the intake resistance (pressure loss) increases. Accordingly, there is a problem that the air flow rate when the throttle valve is fully opened is reduced and the performance of the internal combustion engine is deteriorated.

Japanese Patent Laid-Open No. 11-258019 JP 2006-234766 A Japanese Patent No. 3263167

  An object of the present invention is to improve the productivity by shortening the manufacturing time for manufacturing a hollow body, and to reduce the manufacturing cost, the hollow body manufacturing method, the hollow body, the flow rate measuring device manufacturing method, and the flow rate measurement. To provide an apparatus. Another object of the present invention is to provide a method for manufacturing a hollow body, a method for manufacturing a hollow body, a flow rate measuring device, and a flow rate measuring device that can improve the joint strength of the joint portion of the pair of semi-hollow bodies. Furthermore, a hollow body manufacturing method, a hollow body, a manufacturing method of a flow rate measuring device, and a flow rate measuring device capable of suppressing the occurrence of problems such as leakage of a molten material as a secondary molding material to the flow path side are provided. It is in. Another object of the present invention is to provide a method for manufacturing a hollow body, a method for manufacturing a hollow body, a flow rate measuring device, and a flow rate measuring device capable of suppressing the occurrence of problems such as deformation of a joint portion of a pair of semi-hollow bodies.

The invention according to claim 1 is a manufacturing method for obtaining a hollow body in which a hollow portion is formed by joining a joint portion of a pair of semi-hollow bodies formed of a primary molding material with a secondary molding material. , Each of the joint portions of the pair of semi-hollow bodies has an outer partition wall disposed on the outer side of the hollow portion and a central partition wall disposed on the inner side of the hollow portion.
And the manufacturing process which obtains the hollow body in which the hollow part was formed in the inside WHEREIN: The primary shaping | molding process which shape | molds a pair of semi-hollow body with a primary molding material so that it may have a junction part (an outer partition and a central partition are included). And a secondary molding material in a molding die for secondary molding so that the outer partition wall is fused and fixed with the secondary molding material and the central partition wall is sandwiched with the joint end faces of the joint portion being in contact with each other. A secondary molding step of injecting and filling the molten material to join the joints.

  According to the first aspect of the present invention, the production process for obtaining the hollow body in which the hollow portion is formed includes the primary molding process and the secondary molding process described above, thereby performing the secondary molding once. During the process, the joint end face of the outer partition wall and the joint end face of the central partition wall can be joined at the same time in the joint part of the pair of semi-hollow bodies, so that the manufacturing time for manufacturing the hollow body is shortened and the productivity is improved. At the same time, the manufacturing cost can be reduced.

In addition, the outer partition walls of the pair of semi-hollow bodies are fused and fixed with a secondary molding material, and the central partition walls of the pair of semi-hollow bodies are sandwiched with the secondary molding material to join the pair of semi-hollow bodies. The joint strength of the joint part of the pair of semi-hollow bodies can be improved.
Moreover, since the joining strength of the joint part of a pair of semi-hollow bodies can be improved, it is not necessary to increase the injection pressure or the resin pressure when injecting and filling the molten material during secondary molding. Thereby, the malfunction which the molten material used as a secondary molding material leaks to the hollow part side can be suppressed.
In addition, since the joint strength of the joint part of the pair of semi-hollow bodies can be improved, the joint part of the pair of semi-hollow bodies may be deformed or the like (a gap may be formed between the joint end surfaces of the joint parts, It is possible to suppress the occurrence of problems such as the occurrence of steps between them.

Furthermore, according to invention of Claim 1, a pair of semi-hollow body has a through-hole which penetrates a central partition (in the thickness direction), respectively. The through hole is opened at the joint end face of the central partition, and is opened at the open end face opposite to the joint end face of the central partition.
Moreover, according to the first aspect of the present invention, the melted material that becomes the secondary molding material is injection-filled 2 into the joint portion of the pair of semi-hollow bodies, for example, the joint end surface of the outer partition wall and the joint end surface of the central partition wall. The next flow path is formed.
According to the second aspect of the present invention, the secondary molding material is a secondary molding resin (molten resin) injected and filled in a molten state in a mold for secondary molding.
Here, in the primary molding step, a pair of semi-hollow bodies are joined to the joint (outer partition wall and the center using a primary molding resin (molten resin) injected and filled in a molding state for primary molding in a molten state. Primary molding may be performed so as to include a partition wall.

According to the third aspect of the present invention, the mold for secondary molding is larger in diameter than the through hole (large in the radial direction) between the opening end surfaces of the central partition walls of the pair of semi-hollow bodies. Flange) has a molding surface that forms a molding space. Thereby, since each center partition of a pair of semi-hollow bodies is pinched | interposed with the secondary molding material (flange) injection-filled in molding space, each center partition of a pair of semi-hollow bodies is joined firmly.
Thus, it is not necessary to increase the injection pressure or the resin pressure when the molten material is injected and filled during the secondary molding. As a result, it is possible to suppress a problem that the molten material that becomes the secondary molding material leaks to the hollow portion side through the joint end surfaces of the central partition wall, so that the flow velocity of the air flow flowing through the hollow portion is reduced or the air is disturbed. There is nothing to do. Accordingly, since the measurement error of the air flow rate is reduced, the measurement accuracy of the air flow rate can be improved.
Moreover, since the joint strength of the joint end face of the central partition wall can be improved, there is a problem that the joint part of the pair of semi-hollow bodies is deformed (a gap is formed between the joint end faces of the joint part or a step between the joint parts). The occurrence of problems such as the occurrence of a fault can be suppressed.

According to invention of Claim 4 , the center partition has a cylinder wall so that the circumference | surroundings of a through-hole may be surrounded. The opening end surface of the cylindrical wall is formed at a position recessed toward the joining end surface side of the central partition wall from the opening end surface of the central partition wall.
In this case, since the opening end surface of the cylindrical wall is recessed toward the joint end surface side of the central partition wall relative to the opening end surface of the central partition wall, the secondary molding material (flange) injected and filled into the molding space is the opening of the central partition wall. The malfunction which protrudes toward the exterior rather than the outer surface of an end surface, ie, a pair of semi-hollow body, can be suppressed.
Here, when the hollow body is installed in an intake pipe (duct) of an internal combustion engine in order to use the hollow body as, for example, a hollow housing (a housing of a flow rate measuring device) in which a flow sensor is installed, The air that flows toward the internal combustion engine through the outside of the body is not disturbed by the protruding portions (joints 131 and 141 in the conventional example 3). For example, the air flow rate when the throttle valve is fully opened is the flow rate as required by the internal combustion engine. Therefore, it is possible to suppress a decrease in the performance of the internal combustion engine.

According to the invention described in claim 5, the molding die for secondary molding forms a molding space having a diameter larger than that of the through hole (a flange having a larger radial dimension) between the opening end surface of the cylindrical wall. Has a molding surface. Thereby, since each center partition of a pair of semi-hollow bodies is pinched | interposed with the secondary molding material (flange) injection-filled in molding space, each center partition of a pair of semi-hollow bodies is joined firmly.
Thus, it is not necessary to increase the injection pressure or the resin pressure when the molten material is injected and filled during the secondary molding. Thereby, the malfunction that the molten material used as the secondary molding material leaks to the hollow portion side through between the joining end faces of the cylindrical wall can be suppressed. Moreover, since the joining strength of the joining end surface of the cylinder wall can be improved, there is a problem that the joining portion of the pair of semi-hollow bodies is deformed (a gap is formed between the joining end surfaces of the joining portion, or a step is formed between the joining portions. The occurrence of problems such as the occurrence of a fault can be suppressed.

According to the sixth aspect of the present invention, the pair of semi-hollow bodies have filling grooves that open at the joint end face of the outer partition wall and communicate with each other. Then, in the secondary molding step, the secondary molding material is filled into the filling groove and the outer partition walls are fused and fixed.
According to the seventh aspect of the present invention, the outer partition wall has a protrusion protruding from the groove wall surface of the filling groove toward the joining end surface side of the outer partition wall. In this case, in the secondary forming step, the molten material is heated so as to have a temperature higher than the melting point of the protrusion, and the molten material is injected and filled into the filling groove, whereby the protrusion melts and disappears with the heat of the molten material. . Thereby, the joining end surface of each outer partition of a pair of semi-hollow bodies is firmly fused and fixed.
As a result, the sealing property for hermetically sealing the gap formed between the joining end faces of the outer partition walls can be improved, so that the molten material that becomes the secondary molding material passes between the joining end faces of the outer partition walls to the hollow portion side. It is possible to suppress problems that leak out.
Moreover, since the joint strength of the joint end face of the outer partition wall can be improved, there is a problem that the joint part of the pair of semi-hollow bodies is deformed (a gap is formed between the joint end faces of the joint part, or there is a step between the joint parts. The occurrence of problems such as the occurrence of a fault can be suppressed.

According to the eighth aspect of the present invention, the gap formed between the joining end surfaces of the outer partition walls is formed by forming a gap in the labyrinth structure having an uneven shape or a bent shape on the joining end surfaces of the outer partition walls. It becomes difficult for the air that circulates through. Thereby, the sealing performance which airtightly seals the gap formed between the joining end faces of the outer partition walls can be improved.
According to the ninth aspect of the present invention, the gap formed between the joint end faces of the central partition wall is formed by forming a gap in the labyrinth structure having an uneven shape or a bent shape on the joint end face of the central partition wall, thereby forming a hollow portion. It becomes difficult for the air that circulates through. Thereby, the sealing performance which airtightly seals the gap formed between the joint end faces of the central partition wall can be improved.

According to invention of Claim 10, the fitting recessed part is formed in the junction end surface of the one side outer partition provided in the junction part of the one half hollow body of a pair of half hollow bodies. Moreover, the fitting convex part is formed in the junction end surface of the outer partition of the other side provided in the junction part of the other half hollow body of a pair of half hollow bodies. Then, by fitting the fitting convex part of the outer partition wall on the other side into the fitting concave part of the outer partition wall on one side, the joint end surface of each outer partition wall of the pair of semi-hollow bodies can be positioned. The positional deviation of the part can be suppressed.

According to invention of Claim 11, the fitting recessed part is formed in the junction end surface of the one side central partition provided in the junction part of the one half hollow body of a pair of half hollow bodies. Moreover, the fitting convex part is formed in the junction end surface of the other side central partition provided in the junction part of the other half hollow body of a pair of half hollow bodies. And, since the fitting projections of the central partition on the other side are fitted into the fitting recesses on the central partition on the one side, the joint end surfaces of the central partition walls of the pair of semi-hollow bodies can be positioned, The positional deviation of the part can be suppressed.

According to the twelfth aspect of the present invention, the pair of semi-hollow bodies respectively have a pair of half-tubular nozzles surrounding the periphery of the inlet portion or the outlet portion of the hollow portion. The pair of halved cylindrical nozzles each have a planar outer wall surface (parallel to the flow direction of the fluid flowing through the hollow portion).
According to the thirteenth aspect of the present invention, the secondary flow path in which the molten material to be the secondary molding material is injected and filled is formed on the joining end surfaces of the pair of halved cylindrical nozzles.
Accordingly, since the secondary flow path can be provided up to the joining end surfaces of the pair of half-cylindrical nozzles, the joining end surfaces of the pair of half-cylindrical nozzles are firmly fused and fixed. Thereby, the joint strength of the joint part of a pair of semi-hollow bodies can be improved.
According to the fourteenth aspect of the present invention, the pair of semi-hollow bodies have filling grooves that open at the joint end surfaces of the pair of half-tubular nozzles and communicate with each other. Then, in the secondary molding step, the secondary molding material is filled into the filling groove, and the pair of halved cylindrical nozzles are fused and fixed.
Accordingly, since the filling groove can be provided up to the joining end surfaces of the pair of half cylindrical nozzles, the joining end surfaces of the pair of half cylindrical nozzles are firmly fused and fixed. Thereby, the joint strength of the joint part of a pair of semi-hollow bodies can be improved.

According to the invention described in claim 15, characterized in that it is a hollow body produced by the method according to any one of claims 1 to 14.
According to the invention described in claim 16, a flow rate measuring device including the hollow body according to claim 15 is manufactured.
According to the invention described in claim 17, in the flow rate measuring device including the hollow body (hollow structure body, hollow housing) according to claim 15, the flow sensor is provided inside the hollow body. Yes.
According to the eighteenth aspect of the invention, the inside of the hollow body is a bypass passage into which a part of the air flowing through the intake passage of the internal combustion engine flows. The flow rate sensor has a flow rate measuring element that measures the flow rate of air flowing through the bypass flow path.
Thereby, since the joint strength of the joint part of the pair of semi-hollow bodies can be improved, it is not necessary to increase the injection pressure or the resin pressure when the molten material is injected and filled during the secondary molding. As a result, it is possible to suppress the problem that the molten material that becomes the secondary molding material leaks to the hollow portion (bypass flow path) side, so that the flow velocity of the air flow flowing through the hollow portion (bypass flow path) decreases or the air is turbulent. There is nothing to do. Accordingly, since the measurement error of the air flow rate is reduced, the measurement accuracy of the air flow rate can be improved.

1 is a configuration diagram illustrating an engine control system (Example 1). FIG. (A), (b) is the front view and side view which showed the air flowmeter (AFM) (Example 1). It is the exploded view which showed the hollow molded object which comprises a hollow module housing (Example 1). (A) is the side view which showed the joining end surface of the 1st semi-hollow molded object, (b) is the side view which showed the joining end surface of the 2nd semi-hollow molded object before mounting | wearing with a thermal type flow sensor. Example 1). (A) is the side view which showed the joining end surface of the 1st semi-hollow molded object, (b) is the side view which showed the joining end surface of the 2nd semi-hollow molded object after mounting | wearing with a thermal type flow sensor. Example 1). It is the side view which showed the hollow molded object after primary shaping | molding (Example 1). (Example 1) which is AA sectional drawing of FIG. It is explanatory drawing which showed the secondary shaping | molding process (Example 1). It is explanatory drawing which showed the hollow molded object after secondary shaping | molding (Example 1). (A), (b) is the front view and side view which showed the air flowmeter (Example 2). (Example 2) which was the exploded view which showed the hollow molded object which comprises a hollow module housing. It is the exploded view which showed the air flow measuring device (conventional example 1). It is explanatory drawing which showed the air flow measuring device (conventional example 2). It is explanatory drawing which showed the manufacturing method of a hollow molded object (conventional example 3).

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
The object of the present invention is to improve the productivity by shortening the production time for producing the hollow body, to reduce the production cost, and to improve the bonding strength of the joint part of the pair of semi-hollow bodies, For the purpose of suppressing the occurrence of problems such as leakage of molten material as a secondary molding material to the hollow part (bypass flow path) side, and the occurrence of problems such as deformation of the joint part of a pair of semi-hollow bodies In the secondary molding process, the outer partition wall is fused and fixed in the secondary molding process, and the secondary molding material is melted into the secondary molding mold so as to sandwich the central partition wall. This was realized by injection filling the material and joining the joints.

[Configuration of Example 1]
FIG. 1 to FIG. 9 show Embodiment 1 of the present invention, FIG. 1 is a view showing an engine control system, FIG. 2 is a view showing an air flow meter (AFM), and FIG. It is the figure which showed the hollow molded object which comprises this module housing.

  The control device (engine control system) of the internal combustion engine of the present embodiment measures the flow rate of intake air (intake air amount, intake air amount: hereinafter referred to as air flow rate) supplied to the combustion chamber of the internal combustion engine (engine) E ( An air flow rate measuring device (measuring and calculating) is provided. The air flow rate measuring device corresponds to an engine control unit (engine control device: hereinafter referred to as ECU) for performing various engine controls such as fuel injection control and air-fuel ratio control, and an air flow rate supplied to the combustion chamber of the engine E. A heating resistance type air flow meter (flow sensor module: hereinafter referred to as AFM) that outputs an electric signal to the microcomputer of the ECU is provided.

The AFM of this embodiment is used as a thermal air flow meter that measures the air flow rate based on the amount of heat released from the heating resistor (flow rate measuring element) as a heat ray.
The AFM is detachably attached to a mounting hole formed at a predetermined position of the intake duct of the engine E by a plug-in method. This AFM includes a hollow molded body (a pair of semi-hollow molded bodies 1, 2, 1, 2, 2, 4, and a coupling member 5) that constitutes a hollow module housing, and an interior of the hollow molded body And a controller case 8 which is provided integrally with the mounting flange 7 of the hollow molded body and forms a controller housing space for housing a controller as a circuit module.

The hollow molded body is a sensor body made of a synthetic resin, and a joint portion of a pair of semi-hollow molded bodies 1 and 2 molded by the primary molded resin is formed by a secondary molded resin (first and second sealing members 3, 4 and the coupling member 5 etc.).
The thermal flow sensor 6 has a flat substrate made of silicon, and a heating resistor and an air temperature detection resistor are formed in a thin film on the surface of the substrate in a predetermined pattern.
The controller has a control circuit that controls the amount of current supplied to the heating resistor, and an output circuit that amplifies the electrical resistance value of the heating resistor (or the voltage value applied to the heating resistor) and outputs it to the ECU. ing.

Here, the joint part of a pair of semi-hollow molded objects 1 and 2 has the 1st, 2nd outer side partition 11, 12 and the center partition 13, etc., respectively. The first and second filling grooves 15 and 16 are formed inside the first and second outer partition walls 11 and 12 of the pair of semi-hollow molded bodies 1 and 2. Further, each central partition wall 13 of the pair of semi-hollow molded bodies 1 and 2 has a square tubular wall 18 having a rectangular tubular shape in which a through hole 17 is formed.
Further, a bypass passage (a portion of the intake air flowing through the intake duct 19 forming the intake passage of the engine E flows into the hollow molded body (between the inner wall surfaces of the pair of semi-hollow molded bodies 1 and 2)). Hollow portions 21 and 22 are formed.
Details of the AFM will be described later.

The engine E of this embodiment is equipped with an air cleaner, an electronic throttle device, an evaporated fuel processing device, a fuel supply device, an ignition device, and the like. The engine E is mounted in an engine room of a vehicle such as an automobile.
Here, the engine E generates engine output by heat energy obtained by burning a mixture of clean outside air (intake air) filtered by an air cleaner and fuel in a combustion chamber. This engine E is a water-cooled multi-cylinder gasoline engine having a plurality of cylinders, and is a four-cycle engine that repeats four strokes (strokes) of an intake stroke, a compression stroke, an expansion (combustion) stroke, and an exhaust stroke as a cycle. Is adopted.
The engine E also includes an intake duct 19 for introducing intake air into the combustion chamber for each cylinder, and an exhaust duct 20 for discharging exhaust gas flowing out from the combustion chamber for each cylinder of the engine E to the outside. It has.

  Here, the air cleaner has a filter element (filtering element) 23 for filtering air (outside air) introduced into the air introduction passage (intake passage) from the outside air inlet opening at the upstream end of the inlet duct (outside air introduction duct). doing. The filter element 23 captures and removes impurities (dust such as dust, dust, and sand) contained in the outside air, so that hard dust is sucked into the combustion chamber of the engine E to slide the engine E. This is an air filter that prevents wear of the air. The filter element 23 is housed and held inside an air cleaner case installed at the most upstream portion of the intake duct 19 of the engine E.

The downstream end of the air cleaner case is connected to the throttle body of the electronic throttle device via the outlet pipe of the air cleaner and the air cleaner hose. Further, the downstream end of the throttle body is connected to the intake port of the engine E via a surge tank and an intake manifold (intake branch pipe). An intake duct 19 is constituted by these air cleaner case, outlet pipe, air cleaner hose, throttle body, surge tank, intake manifold, and the like.
The downstream end of the exhaust port of the engine E is connected to the muffler via an exhaust manifold (exhaust branch pipe) and an exhaust pipe. An exhaust duct 20 is constituted by the exhaust manifold, the exhaust pipe, the muffler, and the like.

The electronic throttle device is a system that variably controls the flow rate of air sucked into the combustion chamber of each cylinder of the engine E according to the throttle opening corresponding to the valve opening of the throttle valve 24.
This electronic throttle device includes a throttle body installed in the middle of the intake duct 19 of the engine E, a butterfly throttle valve 24 that varies the flow rate of air flowing through the intake duct 19, and a closing operation direction of the throttle valve 24 (or It is configured by a return spring (or default spring) or the like that biases in the valve opening operation direction).

The throttle body is also equipped with an electric actuator 25 having a power transmission mechanism such as an electric motor and a gear reduction device that drives a shaft for supporting and fixing the throttle valve 24 in the valve opening operation direction (or valve closing operation direction). Yes. Here, the electric motor that drives the throttle valve 24 is configured to be energized and controlled by the ECU.
Further, a throttle opening sensor 26 for detecting the throttle opening is mounted on the throttle body.

The engine E includes a cylinder head in which a downstream end portion of an intake manifold constituting the most downstream portion of the intake duct 19 and an upstream end portion of an exhaust manifold constituting the most upstream portion of the exhaust duct 20 are hermetically coupled, And a cylinder block that forms a combustion chamber with the head.
A plurality of intake ports formed on one side of the cylinder head are opened and closed by an intake valve 27. A plurality of exhaust ports formed on the other side of the cylinder head are opened and closed by an exhaust valve 28.

Further, the cylinder block includes a knock sensor 29 that detects engine vibration caused by knocking, a cooling water temperature sensor 30 that detects the temperature (cooling water temperature) of engine cooling water that is circulated and supplied to the water jacket of the engine E, and the engine E A crank angle sensor 31 for detecting the crank angle is mounted.
In the cylinder bore formed inside the cylinder block, pistons 32 connected to the crankshaft via connecting rods are supported so as to be slidable in their sliding directions.

The ignition device is a system that ignites and burns the air-fuel mixture when the air-fuel mixture in each combustion chamber of the engine E is compressed as the piston 32 rises.
The ignition device includes an ignition coil (not shown) that generates a high voltage for igniting the air-fuel mixture, and a plurality of spark plugs that ignite the air-fuel mixture by blowing a spark with the high-voltage current generated by the ignition coil. 33 or the like.
A plurality of spark plugs 33 are mounted on the cylinder head corresponding to each cylinder of the engine E.

The intake duct 19 of the engine E is an intake pipe in which an intake passage 34 for supplying intake air to the combustion chamber of each cylinder of the engine E is formed. An AFM is mounted on the intake duct 19.
The exhaust duct 20 of the engine E is an exhaust pipe in which an exhaust passage 35 for discharging exhaust gas flowing out from the combustion chamber of each cylinder of the engine E to the outside through the exhaust purification device is formed.
In this embodiment, catalysts 36 and 37 such as a three-way catalyst for purifying CO, HC, NOx and the like in exhaust gas are employed as the exhaust purification device.
The exhaust duct 20 is also equipped with exhaust gas sensors (air-fuel ratio sensor 38, oxygen sensor 39) that detect the state of the exhaust gas (air-fuel ratio, oxygen concentration, etc.) flowing out from the combustion chamber of each cylinder of the engine E. ing.

  The fuel supply device is a system that supplies the fuel in the fuel tank 41 to a fuel injection valve (injector) of the engine E at a predetermined pressure. A suction filter 42 and a pump module are accommodated in the fuel tank 41. This pump module includes an in-tank type electric fuel pump (fuel pump) 43 installed in the fuel tank 41, a fuel filter 44 disposed around the fuel pump 43, and the like. The fuel supply device also supplies a fuel pump 43 that discharges the sucked-in fuel, a delivery pipe 45 that temporarily stores the high-pressure fuel by the fuel pump 43, and fuel that is distributed and supplied by the delivery pipe 45. And a plurality of injectors 46 for injecting the fuel into the intake port of the engine E at an optimal timing.

The plurality of injectors 46 are mounted on the cylinder head corresponding to each cylinder of the engine E. The fuel pump 43 and the plurality of injectors 46 are configured to be energized and controlled by the ECU.
Here, the fuel in the fuel tank 41 is supplied to the delivery pipe 45 by the fuel pump 43 via the fuel supply pipe. The fuel pressure at this time is adjusted to a predetermined fuel pressure by the pressure regulator 47 in the fuel tank 41.

The evaporative fuel processing apparatus introduces (purifies) the evaporated fuel evaporated in the fuel tank 41 into the intake duct 19 using the intake pipe negative pressure via the canister 48, thereby evaporating in the fuel tank 41. It is a system that prevents vaporized fuel vapor from being released into the atmosphere.
In this fuel vapor processing apparatus, the fuel tank 41 and the canister 48 communicate with each other via a fluid introduction pipe, and the canister 48 and the intake duct 19 communicate with each other via a fluid introduction pipe (purge line).

In the canister 48, an adsorbent (for example, activated carbon) that adsorbs the evaporated fuel is stored. In addition, an air release pipe that is open to the atmosphere is connected to the air release hole (port) of the canister 48.
A purge duty VSV (vacuum switching valve) 49 for controlling a purge flow rate for introducing the evaporated fuel from the canister 48 into the intake duct 19 is installed in the fluid introduction pipe (purge line). The purge duty VSV 49 is configured to be energized and controlled by the ECU.

Next, details of the AFM and ECU of this embodiment will be briefly described with reference to FIGS.
As described above, the AFM is detachably attached to the attachment hole of the intake duct 19 by a plug-in method. This AFM has a hollow molded body, a thermal flow sensor 6, a controller case 8, and the like.

  The hollow molded body is a hollow structure (hollow module housing) in which hollow portions (bypass channels 21 and 22) are formed inside, and a primary molding resin (for example, polybutylene terephthalate (PBT)) is synthesized. Resin (thermoplastic resin)) and secondary molding resin (synthetic resin (thermoplastic resin) same as the primary molding resin) are formed into a predetermined shape and penetrate the mounting hole from the outside of the intake duct 19. It is inserted into the intake duct 19 so as to protrude into the intake passage 34. A mounting flange that is fastened and fixed to the peripheral edge (outer wall surface) of the mounting hole of the intake duct 19 by a fastening screw (not shown) or the like at the upper portion in the height direction of the hollow molded body, particularly the semi-hollow molded body 2 7 is provided.

  An I-shaped bypass flow path is formed in the hollow molded body so as to be parallel to the air flow direction flowing through the intake passage 34 of the intake duct 19 and bypasses the intake passage 34 of the intake duct 19. 21 and a part of the air flow flowing through the bypass passage 21 and a U-shaped bypass passage 22 that bypasses the intake passage 34 of the intake duct 19 are formed. Further, the hollow molded body is obtained by joining the joint portions of the pair of semi-hollow molded bodies 1 and 2 with a secondary molding resin (first and second sealing members 3 and 4 and a coupling member 5 and the like).

The bypass passage 21 bypasses the outside air filtered by the filter element 23 of the air cleaner, bypasses the intake passage 34, the inside of the throttle body, the inside of the surge tank, the inside of the intake manifold, the inside of the cylinder head (intake port). It is an air introduction flow path which introduces into the combustion chamber for every cylinder of engine E via.
The bypass passage 21 is provided in the vicinity of the central axis of the intake duct 19 and is parallel to the direction of air flow through the intake passage 34 (the direction of the average flow of intake air through the intake passage 34). It is a linear flow path that extends straight.
An air inlet 51 through which intake air flows from the intake passage 34 of the intake duct 19 is provided at the upstream end of the bypass passage 21. An air outlet 52 through which intake air flows out to the intake passage 34 of the intake duct 19 is provided at the downstream end of the bypass flow path 21. The air outlet 52 is provided with a tapered throttle portion 57 whose flow path cross-sectional area decreases toward the downstream side in the air flow direction.

The bypass flow path 22 branches from the middle of the bypass flow path 21 and further bypasses the air outlet 52 of the bypass flow path 21 so that the inside of the throttle body, the inside of the surge tank, the inside of the intake manifold, the cylinder head It is an air introduction flow path that is introduced into the combustion chamber of each cylinder of the engine E via the inside (intake port).
The bypass passage 22 branches off upstream of the air outlet 52 of the bypass passage 21 in the air flow direction, and an inclined portion (inclined from the branch portion 53 with respect to the central axis direction of the bypass passage 21 ( (Inclined channel) → Bent part that bends the air flow direction at right angles → Straight line part that extends in the horizontal direction (horizontal direction) in the figure (horizontal flow path) → Bend part that bends the air flow direction at right angles → Vertical direction in the figure (height direction ) Extending in a straight line portion (vertical flow path) → opening on the side wall surfaces of the pair of semi-hollow molded bodies 1 and 2 via an inclined portion (inclined flow path) inclined with respect to the central axis direction of the straight line portion The air outlet 54 is bent while being bent.

In the hollow molded body, the air inlet 51 is opened at the air inlet portion of each of the semi-hollow molded bodies 1 and 2. The air inflow port 51 opens toward the upstream side (air filter side) of the intake passage 34.
In the hollow molded body, the air outlet 52 is opened at the air outlet portion of each of the semi-hollow molded bodies 1 and 2 (the blowout nozzle of the bypass channel 21). The air outlet 52 opens toward the downstream side (throttle body side) of the intake passage 34.
In the hollow molded body, the air outlet 54 is opened at the air outlet portion (blowout nozzle of the bypass channel 22) of each of the semi-hollow molded bodies 1 and 2. The air outlet 54 opens toward the downstream side (throttle body side) of the intake passage 34.

Each of the semi-hollow molded bodies 1 and 2 is integrally provided with a pair of half-cylindrical hood covers 55 and 56 that form the bypass channel 21 and the air outlets 52 and 54 therein. These hood covers 55 and 56 have a streamline shape that smoothly expands in the thickness direction of the hollow molded body toward the downstream side in the air flow direction flowing through the intake passage 34.
Thereby, since the air flowing around the hood covers 55 and 56 of the hollow molded body flows smoothly without stagnation, an increase in the intake resistance (pressure loss) of the main flow of the intake air flowing through the intake passage 34 can be suppressed. .
Details of the pair of semi-hollow molded bodies 1 and 2 will be described later.

  The thermal flow sensor 6 is inserted from a sensor insertion port (not shown) formed in the mounting flange 7 from the upper side of the mounting flange 7 of the semi-hollow molded body 2 to the straight portion (horizontal) of the bypass flow path 22. And a sensing unit 61 installed in the directional flow path. The sensing unit 61 includes a sensor chip having a thin film portion. This sensor chip is installed in a direction orthogonal to the axial direction of the average flow of the intake air flowing through the bypass flow path 22.

The sensor chip has a flat substrate parallel to the flow direction of the air flowing through the bypass flow path 22, and an insulating support film made of silicon nitride is formed on the surface of the substrate. On the support film, a flow rate detection unit (heating resistor, air temperature detection resistor) constituting the sensing element and an electrode pad group electrically connected to a control circuit built in the controller are formed. ing. An insulating protective film made of silicon nitride for protecting the flow rate detection unit is formed on the flow rate detection unit.
The sensor chip is provided with a membrane (thin film portion) formed by etching the substrate from the back surface.

The flow rate detection unit consists of a thin-film heating resistor (heater resistor) that generates heat at a high temperature due to the heating current flowing through itself, and a thin-film air temperature detection resistor (temperature-sensitive resistor) whose resistance value changes depending on the ambient temperature. ).
The heating resistor is a flow rate measuring element for measuring the flow rate of air flowing through the bypass passage 22, and for example, platinum (Pt), polysilicon (Poly-Si), single crystal silicon, or the like is detected by vacuum deposition or sputtering. A thin film is formed in a predetermined pattern on the chip membrane.

The air temperature detection resistor is a temperature sensing element (temperature sensor resistor) for measuring the temperature of the intake air flowing through the bypass passage 22 (intake air temperature), and, like the heating resistor, vacuum deposition or sputtering. Thus, a platinum film (Pt), a polysilicon film (Poly-Si), a single crystal silicon film, or the like formed in a predetermined pattern on the membrane of the sensor chip.
Terminals that electrically connect the wiring portions and electrode pads of the heating resistor and the control circuit built in the controller, and terminals that electrically connect the air temperature detection resistor and electrode pads and the control circuit are insulative. It protrudes upward in the figure from the opening of the protective case 62 in the shape of a square bag formed of resin. Further, the connecting portion between the heating resistor and the air temperature detection resistor and each terminal is molded in a potting resin.

  The controller is accommodated in a controller accommodating space formed between the upper end portion of the mounting flange 7 of the hollow molded body and the lower end portion of the controller case 8, and is attached to the mounting flange 7 or the controller case 8 of the hollow molded body. It is installed. This controller is disposed outside the mounting hole of the intake duct 19. The controller includes a control circuit and an output circuit on a built-in circuit board, and a thermistor (not shown) as an intake air temperature sensor that detects the air temperature of the intake passage 34.

  The control circuit is electrically connected to the heating resistor and the air temperature detection resistor via each terminal, electrode pad, and wiring portion. The control circuit then supplies the heating resistor (current value, power) so that the temperature deviation between the heating temperature of the heating resistor and the intake air temperature detected by the air temperature detection resistor becomes a constant value. Amount). That is, the control circuit is an energization control circuit that controls energization (current) of the heating resistor.

  Here, the heating temperature of the heating resistor is determined based on the electric resistance value of the air temperature detection resistor, and is substantially constant with respect to the ambient temperature (the intake air temperature detected by the air temperature detection resistor) by the control circuit. Is controlled so as to have a temperature difference (ΔT). Specifically, for example, when ΔT of the heating resistor is controlled to 200 ° C., energization control is performed so that the temperature of the heating resistor becomes about 220 ° C. when the ambient temperature (intake air temperature) is 20 ° C. The energization is controlled so that the temperature of the heating resistor is about 240 ° C. when the ambient temperature (intake air temperature) is 40 ° C.

The output circuit outputs the amount of heat released from the heating resistor to the intake air flowing around the heating resistor as an electrical signal to the ECU. For example, a heating resistor and an air temperature detection resistor are incorporated in a bridge circuit, and a constant electrical resistance value (heating temperature) is always maintained even if the heat radiation amount of the heating resistor changes due to the intake air flow flowing around the heating resistor. However, current control is performed so as to maintain temperature compensation, and the current value is converted into a voltage and output to the ECU as an air flow voltage signal.
The controller case 8 is formed integrally with the upper portion of the mounting flange 7 in the figure. The controller case 8 includes a connector housing 63 that holds a plurality of terminals that electrically connect the above-described controller and an external ECU.

Here, the ECU includes a CPU that performs control processing and arithmetic processing, a control program or control logic, a storage device that stores various data (memory such as ROM and RAM), a timer, and the like. A microcomputer is provided.
The ECU also includes an electrical signal (AFM output signal) output from the output circuit of the controller of the AFM, including a throttle opening sensor 26, a knock sensor 29, a coolant temperature sensor 30, a crank angle sensor 31, an exhaust gas sensor (air-fuel ratio). Sensor output signals from various sensors such as the sensor 38, the oxygen sensor 39), and the thermistor are A / D converted by the A / D converter and then input to the microcomputer. This microcomputer is used for various engine controls (for example, fuel injection control, air-fuel ratio control, EGRV opening degree control, etc.) based on an electrical signal (for example, an AFM output signal such as an air flow rate voltage signal) output from the AFM. Measure (calculate) the air flow rate and flow velocity.

Then, the ECU calculates the air flow rate based on the electric signal (AFM output signal) output from the AFM, calculates the fuel injection amount based on the calculated air flow rate, and calculates the calculated fuel injection amount. Accordingly, the energization time (valve opening period) of the injector 46 is variably controlled, and the energization time of the injector 46 is controlled in association with each system such as an electronic throttle device, a fuel supply device (fuel injection device), and an ignition device. It is configured as follows.
The ECU also controls the electric actuator 25 including an electric motor that drives the shaft of the throttle valve 24, the electric motor of the fuel pump 43, and the electromagnetic actuator of the purge duty VSV 49 based on sensor output signals from the various sensors.

Next, the details of the pair of semi-hollow molded bodies 1 and 2 according to the present embodiment will be briefly described with reference to FIGS.
As shown in FIGS. 3 to 6, the semi-hollow molded body 1 has an I-shaped bypass flow channel groove (i.e., a bypass flow channel 21) on the joint end surface side abutted against the joint end surface of the semi-hollow molded body 2. (Hereinafter abbreviated as a channel groove) and a U-shaped bypass channel groove (hereinafter abbreviated as a channel groove) to be the bypass channel 22.

  The semi-hollow molded body 1 has a one-letter-shaped first portion installed on the outer side (the lower side in the height direction of the intake duct 19, the lower side in the drawing) than the flow channel as the bypass flow channel 21. 1 Outside partition wall (thick part, block) 11, outside of the channel groove as the bypass channel 22 (front and rear sides (upstream / downstream side) in the front-rear direction (air flow direction) of the intake duct 19) and the intake duct 19 The U-shaped second outer partition wall (thick part, block) 12 installed on the upper side in the height direction (upper side in the figure) and the channel groove as the bypass channel 22 are installed on the inner side. A central partition wall 13 (thick part, block) having a predetermined shape is provided.

  As shown in FIGS. 3 to 6, the semi-hollow molded body 2 has an I-shaped bypass channel groove (i.e., a bypass channel 21) on the side of the joint end surface that is abutted against the joint end surface of the semi-hollow molded body 1. (Hereinafter abbreviated as a channel groove) and a U-shaped bypass channel groove (hereinafter abbreviated as a channel groove) to be the bypass channel 22.

  The semi-hollow molded body 2 has a one-letter-shaped first portion installed on the outer side (the lower side in the height direction of the intake duct 19, the lower side in the drawing) with respect to the channel groove as the bypass channel 21. 1 Outside partition wall (thick part, block) 11, outside of the channel groove as the bypass channel 22 (front and rear sides (upstream / downstream side) in the front-rear direction (air flow direction) of the intake duct 19) and the intake duct 19 The U-shaped second outer partition wall (thick part, block) 12 installed on the upper side in the height direction (upper side in the figure) and the channel groove as the bypass channel 22 are installed on the inner side. A central partition wall 13 (thick part, block) having a predetermined shape is provided.

  The first and second outer partition walls 11 and 12 and the central partition wall 13 provided in the semi-hollow molded body 2 correspond to the first and second outer partition walls 11 and 12 and the central partition wall 13 provided in the semi-hollow molded body 1. Is formed. That is, when the joined portions of the pair of semi-hollow molded bodies 1 and 2 are butted together during the manufacturing process, the joining end surfaces of the first outer partition walls 11 of the pair of semi-hollow molded bodies 1 and 2, the pair of semi-hollow molded bodies The joint end faces of the first and second second outer partition walls 12 and the joint end faces of the central partition walls 13 of the pair of semi-hollow molded bodies 1 and 2 are provided in correspondence with each other.

On the joint end face of each first outer partition 11 of the pair of semi-hollow molded bodies 1 and 2, a U-shaped first filling groove 15 communicating with each other is formed. The first filling groove 15 is opened at the joining end face of the first outer partition wall 11. Further, on each filling groove wall surface (especially, the filling groove bottom surface) of the first filling groove 15, a first protrusion 71 protruding from the filling groove bottom surface toward the joining end face side of the first outer partition wall 11 is formed. Since the first protrusion 71 melts and disappears during the secondary molding process, the first outer partition wall 11 is fused and fixed to the secondary molding resin, and between the bypass channel 21 and the outside (the intake channel 34). A hermetic seal is made.
The space surrounded by the first and second filling grooves 15 and 16 of the semi-hollow molded body 1 and the first and second filling grooves 15 and 16 of the semi-hollow molded body 2 is secondary during the secondary molding step. A two-letter flow path in which a molding resin is injected and filled is formed.

U-shaped second filling grooves 16 communicating with each other are formed on the joining end surfaces of the second outer partition walls 12 of the pair of semi-hollow molded bodies 1 and 2, respectively. The second filling groove 16 is opened at the joining end face of the second outer partition 12. Further, on each filling groove wall surface (especially the filling groove bottom surface) of the second filling groove 16, a second protrusion 72 is formed that protrudes from the filling groove bottom surface toward the joining end face side of the second outer partition wall 12. Since the second protrusion 72 melts and disappears during the secondary molding step, the second outer partition wall 12 is fused and fixed to the secondary molding resin, and the bypass channel 21 and the outside (the intake passage 34) are bypassed. An airtight seal with the passage 22 is formed. In addition, the thickness of the second outer partition 12 of the semi-hollow molded body 2 increases as it approaches the mounting flange 7. That is, the joint end surface of the second outer partition 12 of the hollow molded body 2 has an upward slope.
The space surrounded by the second filling groove 16 of the semi-hollow molded body 1 and the second filling groove 16 of the semi-hollow molded body 2 is a two-character flow in which the secondary molding resin is injected and filled during the secondary molding step. Configure the road.

  Here, a plurality of fitting protrusions 73 are formed on the joining end face of the second outer partition 12 of the semi-hollow molded body 1. These fitting protrusions 73 are provided so as to protrude from the joint end face of the second outer partition 12 by a predetermined protrusion amount. A plurality of fitting recesses 74 that fit into the plurality of fitting protrusions 73 are formed on the joint end face of the second outer partition 12 of the semi-hollow molded body 2. These fitting recesses 74 are provided so as to be recessed from the joint end surface of the second outer partition 12 by a predetermined amount of depression.

  The plurality of fitting recesses 74 are provided corresponding to the plurality of fitting protrusions 73 provided on the joining end surface of the second outer partition 12. That is, when the joining parts of the semi-hollow molded bodies 1 and 2 are abutted in the manufacturing process, the plurality of fitting convex parts 73 and the plurality of fitting concave parts 74 are provided so as to be fitted. Thus, a labyrinth gap having an uneven shape is formed between the joint end surface of the second outer partition wall 12 of the semi-hollow molded body 1 and the joint end surface of the second outer partition wall 12 of the semi-hollow molded body 2. . In addition, the joining end surface of the second outer partition wall 12 of the semi-hollow molded body 1 and the joining end surface of the second outer partition wall 12 of the semi-hollow molded body 2 are positioned.

Triangular hole-shaped through-holes 17 communicating with each other are formed on the joining end surfaces of the central partition walls 13 of the pair of semi-hollow molded bodies 1 and 2, respectively. The through hole 17 is provided so as to penetrate the central partition wall 13 in the thickness direction. The central partition wall 13 has a triangular cylindrical wall 18 that surrounds the periphery of the through hole 17.
The through-hole 17 opens at the joint end surface of the central partition wall 13 and the rectangular tube wall 18, and opens at the open end surface opposite to the joint end surface side of the square tube wall 18. In addition, the open end surface of the rectangular tube wall 18 is formed at a position recessed toward the joint end surface side of the central partition wall 13 relative to the open end surface of the central partition wall 13 as shown in FIGS. That is, the opening end surface of the square tube wall 18 is formed to be recessed by a predetermined amount of depression from the joint end surface of the central partition wall 13.

  Here, a plurality of fitting convex portions 75 are formed on the joining end face of the central partition wall 13 of the semi-hollow molded body 1. These fitting protrusions 75 are provided so as to protrude from the joint end surface of the central partition wall 13 by a predetermined protrusion amount. A plurality of fitting recesses 76 that fit into the plurality of fitting protrusions 75 are formed on the joint end face of the central partition wall 13 of the semi-hollow molded body 2. These fitting recesses 76 are provided so as to be recessed from the joint end surface of the central partition wall 13 by a predetermined amount of depression.

  The plurality of fitting recesses 76 are provided corresponding to the plurality of fitting projections 75 provided on the joining end surface of the central partition wall 13. In other words, when the joining portions of the semi-hollow molded bodies 1 and 2 are abutted during the manufacturing process, the plurality of fitting convex portions 75 and the plurality of fitting concave portions 76 are provided so as to be fitted. Thereby, a gap of a labyrinth structure having an uneven shape is formed between the joint end surface of the central partition wall 13 of the semi-hollow molded body 1 and the joint end surface of the central partition wall 13 of the semi-hollow molded body 2. In addition, the joining end surface of the central partition wall 13 of the semi-hollow molded body 1 and the joining end surface of the central partition wall 13 of the semi-hollow molded body 2 are positioned.

  The first seal member 3 has a U-shape (three-dimensional shape) corresponding to the shape of the internal space (filling space) formed by the first filling grooves 15 of the pair of semi-hollow molded bodies 1 and 2 by the secondary molding resin. ). The first sealing member 3 is a first filling member that is filled in an internal space (filling space) formed by the first filling grooves 15 of the pair of semi-hollow molded bodies 1 and 2 during the secondary molding step. . The first seal member 3 is fused to the filling groove wall surface of the first outer partition wall 11 in each first filling groove 15. Thereby, since the gap formed between the joining end faces of the first filling groove 15 is sealed by the first seal member 3, the outside of the hollow molded body (intake passage 34) and the inside of the hollow molded body (bypass channel 21). ) Is airtightly partitioned.

  The second seal member 4 has a U-shape (three-dimensional shape) corresponding to the shape of the internal space (filling space) formed by the second filling grooves 16 of the pair of semi-hollow molded bodies 1 and 2 by the secondary molding resin. ). The second sealing member 4 is a second filling member that fills an internal space (filling space) formed by the second filling grooves 16 of the pair of semi-hollow molded bodies 1 and 2 during the secondary molding step. . The second seal member 4 is fused to the filling groove wall surface of the second outer partition wall 12 in each second filling groove 16. Thereby, since the gap formed between the joining end faces of the second filling groove 16 is sealed by the second seal member 4, the outside of the hollow molded body (intake passage 34) and the inside of the hollow molded body (bypass channel 21). ) And the inside of the hollow molded body (bypass channel 22) are hermetically partitioned.

The coupling member 5 is formed in a predetermined shape (for example, a letter shape of a cross section H) by secondary molding resin. As illustrated in FIGS. 3, 8, and 9, the coupling member 5 includes a triangular prism-shaped intermediate coupling portion (shaft-shaped filling portion) 80 that is filled in the through hole 17.
One end portion of the intermediate connecting portion 80 in the axial direction protrudes from the opening end surface of the rectangular tube wall 18 of the central partition wall 13 and is filled in a flange forming space (first flange forming space) on one side described later. The flange 81 is formed. The flange 81 is a flange having a larger diameter than the through hole 17, that is, a flange having a larger dimension in the radial direction than the through hole 17, and is in close contact with the open end surface of the rectangular tube wall 18.

The other end portion of the intermediate connecting portion 80 in the axial direction protrudes from the opening end surface of the rectangular tube wall 18 of the central partition wall 13 and is filled in a flange forming space (second flange forming space) on the other side described later. The flange 82 has a shape. The flange 82 is a flange having a diameter larger than that of the through hole 17, that is, a flange having a larger dimension in the radial direction than the through hole 17, and is in close contact with the open end surface of the rectangular tube wall 18.
Here, at the time of the secondary molding step, when the molten resin, which is the secondary molding resin, is injected and filled into a molding die for secondary molding, the joining member is joined to join the joint portions of the pair of semi-hollow molded bodies 1 and 2. The open end surface of the rectangular tube wall 18 of the central partition 13 is sandwiched between the five flanges 81 and 82. As a result, the pair of semi-hollow molded bodies 1 and 2 having the central partition wall 13 are firmly joined and integrated.

[Production Method of Example 1]
Next, a method for manufacturing a hollow molded body constituting the hollow module housing of the AFM of this embodiment will be briefly described with reference to FIGS. Here, FIG. 7 thru | or FIG. 9 is the figure which showed the manufacturing process of the hollow molded object.

Here, a synthetic resin (thermoplastic resin) such as polybutylene terephthalate (PBT) is employed as the primary molding resin and the secondary molding resin for molding the hollow molded body.
In addition, the AFM of the present example is a pair of semi-hollow molded bodies 1 by injection filling a molten resin that becomes a primary molding resin that is heated and injected and filled in a molten state into an injection mold for primary molding. A primary molding step for primary molding 2 and injection molding of a molten resin that becomes a secondary molding resin that is heated and injected and filled in a molten state in an injection mold for secondary molding. It can be obtained by carrying out a secondary molding step for secondary molding of the joint portions of the hollow molded bodies 1 and 2.

First, the injection molding method of the semi-hollow molded body 1 will be briefly described. A pellet-shaped resin material is heated and melted, and pressure is applied to the molten resin (primary molding resin injected and filled in a molten state). Injection filling (injection injection) into the cavity of the injection mold for primary molding (the first cavity having a shape corresponding to the product shape of the semi-hollow molded body 1 (see FIGS. 3 to 7)), cooling and solidifying After (curing), the injection molding die for primary molding is punched in a predetermined die cutting direction, and the semi-hollow molded body 1 is taken out from the injection molding die for primary molding (primary molding step).
Here, in the primary molding step of the semi-hollow molded body 1, injection molding (primary molding) is performed so as to have the channel grooves and the joints as the bypass channels 21 and 22.

Next, the injection molding method of the semi-hollow molded body 2 will be briefly described. A pellet-shaped resin material is heated and melted, and pressure is applied to the molten resin (primary molding resin injected and filled in a molten state). Injection filling (injection injection) into the cavity of the injection mold for primary molding (second cavity having a shape corresponding to the product shape of the semi-hollow molded body 2 (see FIGS. 3 to 7)), and cooling After solidification (curing), the injection molding die for primary molding is punched in a predetermined die cutting direction, and the semi-hollow molded body 2 is taken out from the injection molding die for primary molding (primary molding step). .
Here, in the primary molding step of the semi-hollow molded body 2, injection molding (primary molding) is performed so as to have the channel grooves and the joints as the bypass channels 21 and 22.
In addition, two first and second cavities may be provided in one injection molding die for primary molding, and the pair of semi-hollow molded bodies 1 and 2 may be simultaneously primary molded simultaneously.

Next, an injection mold for secondary molding will be described. An injection mold for secondary molding includes a fixed mold made of at least one mold (block) and a movable mold made of at least one mold (slide block, slide core, etc.). . Note that the movable mold is movable in a predetermined mold release direction with respect to the fixed mold.
Further, the injection molding mold (fixed mold and movable mold) for secondary molding has a plurality of molds 91 and 92. In these molds 91 and 92, cavities (molding spaces having flange molding spaces 93 and 94) having a shape corresponding to the product shape of the hollow molded body constituting the hollow module housing of the AFM are formed.
At least one of the plurality of molds 91 and 92 is provided with a resin supply channel and a gate for communicating the outside of the injection mold for secondary molding and the cavity (flange molding spaces 93 and 94). It has been.

Further, the first and second filling grooves 15 and 16 of the pair of semi-hollow molded bodies 1 and 2 of the present embodiment include an outside of the injection molding die for secondary molding and a cavity (first and second filling grooves 15). , 16 internal space, seal molding space) are provided through the resin supply flow path, the first and second gates (not shown) are provided. The first gate is a through hole formed at an arbitrary position (for example, the groove bottom surface) of the first filling groove 15. The second gate is a through-hole formed at an arbitrary position (for example, the groove bottom surface) of the second filling groove 16. One of the first and second gates may be eliminated.
And molten resin is inject | poured into the resin supply flow path, a gate, or the 1st, 2nd gate from the injection nozzle of the injection apparatus arrange | positioned outside the injection molding die for secondary molding. In addition, an ejector mechanism having an ejector pin is mounted on an injection mold for secondary molding.

  Here, the mold 91 has a first molding surface that forms a flange molding space 93 larger in diameter than the through-hole 17 between the opening end surface of the square tube wall 18 of the central partition wall 13. The flange forming space 93 is a forming space in which the flange 81 of the coupling member 5 is formed between the open end surface of the rectangular tube wall 18 of the central partition wall 13 and the first forming surface of the mold 91. The mold 92 has a second molding surface that forms a flange molding space 94 having a diameter larger than that of the through-hole 17 between the opening end surface of the rectangular tube wall 18 of the central partition wall 13. The flange forming space 94 is a forming space in which the flange 82 of the coupling member 5 is formed between the opening end surface of the square tube wall 18 of the central partition wall 13 and the second forming surface of the mold 92.

In the secondary molding step of joining the pair of semi-hollow molded bodies 1 and 2 with the secondary molding resin, first, the pair of semi-hollow molded bodies 1 and 2 are in contact with the joining end surfaces in the injection molding die for secondary molding. Then, the injection mold is closed by applying a clamping force to the plurality of molds 91 and 92 of the injection mold for secondary molding (mold closing process).
Here, when the pair of semi-hollow molded bodies 1 and 2 are held (set) in a state in which the joining end surfaces are butted together, the fitting convex portion 73 of the second outer partition wall 12 of the semi-hollow molded body 1 and the semi-hollow molded body The fitting recess 74 of the second outer partition wall 12 is fitted into the fitting projection 75 of the center partition wall 13 of the semi-hollow molded body 1 and the fitting recess 76 of the center partition wall 13 of the semi-hollow molded body 2. When fitted, positioning of the joining end surface of the semi-hollow molded body 1 and the joining end surface of the semi-hollow molded body 2 can be easily performed. Thereby, the position where the first and second filling grooves 15 and 16 of the semi-hollow molded body 1 and the first and second filling grooves 15 and 16 of the semi-hollow molded body 2 communicate with each other, and the At the position where the through hole 17 and the through hole 17 of the semi-hollow molded body 2 communicate with each other, the joining end surfaces of the pair of semi-hollow molded bodies 1 and 2 are abutted. Moreover, the position shift of the bypass flow paths 21 and 22 can be suppressed.

Next, when the mold closing process is completed, the filling process is started. When the filling process is started, the molten resin injected from the injection nozzle of the injection device (secondary molding resin that is heated and melted) passes through the first and second gates and passes through the first and second filling grooves. 15 and 16 are injected and filled into the interior space, and after passing through the gate, are filled into the cavities (inside spaces of the flange forming spaces 93 and 94 and the through hole 17).
That is, the molten resin is injected and injected into a secondary molding injection mold (a plurality of molds 91, 92, etc.) from the injection nozzle via the resin supply flow path, and the first and second filling grooves 15, The molten resin is filled in the internal space of 16 and the cavities (internal spaces of the flange forming spaces 93 and 94 and the through holes 17) (filling step).

Next, when the filling process is completed, a pressure holding process and a cooling process are subsequently started. In this pressure holding step, the pressure applied from the first and second gates and the gates to the internal spaces and cavities of the first and second filling grooves 15 and 16 (the internal spaces of the flange forming spaces 93 and 94 and the through holes 17) is applied. It is maintained almost constant and is replenished with the shrunken molten resin.
That is, in the pressure-holding step of holding the molten resin in the internal spaces of the first and second filling grooves 15 and 16 and in the cavities (internal spaces of the flange forming spaces 93 and 94 and the through holes 17), the first and second While continuing to pressurize the molten resin in the internal spaces of the filling grooves 15 and 16 and in the cavities (internal spaces of the flange forming spaces 93 and 94 and the through holes 17), a cooling water channel (not shown) is provided around the cavities. The cooling water is introduced into the interior space of the first and second filling grooves 15 and 16 and the cavity (flange molding space 93, 94 and the internal space of the through-hole 17).

In the cooling process for cooling the molten resin in the internal spaces of the first and second filling grooves 15 and 16 and in the cavities (internal spaces of the flange forming spaces 93 and 94 and the through holes 17), the pressure holding process is followed. The molten resin in the internal spaces of the first and second filling grooves 15 and 16 and in the cavities (the internal spaces of the flange forming spaces 93 and 94 and the through holes 17) is cooled and gradually cured (solidified) over time. Go.
Next, after completion of the cooling process including the pressure holding process, the injection mold is opened (mold opening process).
After completion of the mold opening process, an incidental ejector mechanism is operated on the injection molding die for secondary molding, and a hollow molded body (injection) is selected from the plurality of molds 91 and 92 of the injection molding die for secondary molding. (Molded product) is taken out (takeout step).

Here, in the secondary molding process as described above, the first and second molten resins heated to the melting points of the first and second protrusions 71 and 72 provided in the first and second filling grooves 15 and 16 are first and second. When the filling grooves 15 and 16 are injected and filled, the first and second protrusions 71 and 72 made of the primary molding resin projecting into the first and second filling grooves 15 and 16 are melted to melt the resin (secondary molding). The first and second protrusions 71 and 72 disappear.
Thereby, since the gap formed between the joining end faces of the first filling groove 15 is sealed by the first seal member 3, the outside of the hollow molded body (intake passage 34) and the inside of the hollow molded body (bypass channel 21). ) Is airtightly partitioned. Further, since the gap formed between the joining end faces of the second filling groove 16 is sealed by the second seal member 4, the outside of the hollow molded body (intake passage 34) and the inside of the hollow molded body (bypass flow path 21). And the inside of the hollow molded body (bypass channel 22) are hermetically partitioned.

Therefore, since the sealing performance for hermetically sealing the gap formed between the joining end surfaces of the first and second outer partition walls 11 and 12 of the pair of semi-hollow molded bodies 1 and 2 can be improved, As a result, it is possible to prevent the molten resin from leaking to the bypass flow path side through between the joining end faces of the first and second outer partition walls 11 and 12, so that the flow velocity of the air flow flowing through the bypass flow paths 21 and 22 is reduced. And the air is not disturbed. Accordingly, since the measurement error of the air flow rate is reduced, the measurement accuracy of the air flow rate can be improved.
In addition, since the bonding strength of the bonding end surfaces of the first and second outer partition walls 11 and 12 can be improved, a problem such as deformation of the bonding portions of the pair of semi-hollow molded bodies 1 and 2 (between the bonding end surfaces of the bonding portions). It is possible to suppress the occurrence of defects such as gaps being formed or steps formed between the joints.

Further, in the secondary molding process, the molten resin is injected and filled (injection injection) into the flange molding spaces 93 and 94 and the internal space of the through-hole 17, and after cooling and solidifying (curing), the secondary molding is used. When the hollow molded body is taken out from the injection mold, the opening end face of the square tubular wall 18 of the central partition wall 13 is sandwiched between the flanges 81 and 82 of the coupling member 5. As a result, the pair of semi-hollow molded bodies 1 and 2 having the central partition wall 13 are firmly joined and integrated.
As described above, by performing the secondary molding step after the primary molding step, the joint portion of the hollow molded body is joined and integrated.

[Operation of Example 1]
Next, the operation of the engine control system including the AFM (thermal air flow meter) of the present embodiment will be briefly described with reference to FIGS.

  When the ignition switch is turned on (IG / ON), the ECU controls energization of the electric actuator 25 including an electric motor that drives the throttle valve 24, and also includes an ignition device (ignition coil, spark plug 33, etc.) and a fuel injection device. (Electric motor of fuel pump 43, a plurality of injectors 46, etc.) are driven. As a result, the engine E is operated.

Then, when the specific cylinder of the engine E shifts from the exhaust stroke to the intake stroke in which the intake valve 27 is opened and the piston 32 is lowered, the negative pressure (lower than the atmospheric pressure) in the combustion chamber of the cylinder is lowered as the piston 32 is lowered. The pressure is increased, and the air-fuel mixture is sucked from the open intake port.
At this time, a flow of intake air is generated in the intake passage 34 communicating with the intake port that is opened. When a flow of intake air is generated in the intake passage 34, a part of the clean intake air filtered by the filter element 23 of the air cleaner flows into the bypass passage 21 of the hollow molded body in the AFM.

Then, part of the intake air that has flowed into the bypass flow channel 21 flows into the bypass flow channel 22 that branches from the bypass flow channel 21 inside the hollow molded body in the AFM.
And in the sensing part 61 of the thermal flow sensor 6 installed in the bypass flow path 22, when the flow velocity of the intake air flow (bypass flow) flowing through the bypass flow path 22 increases, the heat dissipation amount of the heating resistor increases. Therefore, in order to keep the temperature deviation (ΔT) from the intake air temperature measured by the air temperature detection resistor at a constant value, the amount of supply current supplied from the control circuit of the controller to the heating resistor increases.

Conversely, when the flow velocity of the intake air flow flowing through the bypass flow path 22 is reduced, the heat dissipation amount of the heating resistor is reduced, so that the amount of supply current supplied from the control circuit of the controller to the heating resistor is reduced.
An electrical signal (AFM output signal) is output from an output circuit of the controller to an external ECU in accordance with the amount of current supplied to the heating resistor, and the combustion chamber of each cylinder of the engine E is detected by a microcomputer built in the ECU. The air flow rate introduced into the is measured (calculated). The microcomputer calculates the basic injection time from the air flow rate measured by the AFM and the engine rotational speed, and outputs the basic injection time from various sensors such as the throttle opening sensor 26, the cooling water temperature sensor 30, and the intake air temperature sensor (thermistor). The total output time (fuel injection amount) is calculated by correcting the sensor output signal. The microcomputer controls the energization time and injection timing of the injector 46 according to the fuel injection amount.

[Effect of Example 1]
As described above, the hollow molded body used as the module housing of the AFM of this embodiment is a primary molded resin that is injected and filled in a molten state in an injection mold for primary molding in the primary molding step. By the (primary molding material), a pair of semi-hollow molded bodies 1 and 2 having joint portions (first and second outer partition walls 11 and 12, central partition wall 13 and the like) are primarily molded (manufactured). The pair of semi-hollow molded bodies 1 and 2 may be subjected to primary molding (injection molding) at the same time with one primary molding injection mold, or two or more primary molding injection moldings. Primary molding (injection molding) may be performed separately for each mold.

Next, in the secondary molding step that is performed after primary molding of the pair of semi-hollow molded bodies 1, 2, with the joint end surfaces of the joint portions of the pair of semi-hollow molded bodies 1, 2 abutting each other, Each of the first and second of the pair of semi-hollow molded bodies 1 and 2 is formed by a secondary molding resin (first and second seal members 3 and 4) injected and filled in a molten state into an injection mold for secondary molding. The outer partition walls 11 and 12 are fixed by fusion. At the same time, each of the central partition walls 13 of the pair of semi-hollow molded bodies 1 and 2 is formed by a secondary molding resin (flanges 81 and 82 of the coupling member 5) injected and filled in a molten state in an injection mold for secondary molding. Square tube wall 18 is sandwiched from both sides in the thickness direction.
By performing the secondary molding step as described above, the joining end surfaces of the joint portions of the pair of semi-hollow molded bodies 1 and 2 are joined, and the pair of semi-hollow molded bodies 1 and 2 are integrally coupled.

Thereby, in one secondary molding step, the joint end surfaces of the first and second outer partition walls 11 and 12 and the joint end surface of the central partition wall 13 in the joint portion of the pair of semi-hollow molded bodies 1 and 2. Can be joined simultaneously, so that the production time for producing the hollow molded body can be shortened to improve the productivity and the production cost can be reduced.
Further, the first and second outer partition walls 11 and 12 of the pair of semi-hollow molded bodies 1 and 2 are fused and fixed with a secondary molding resin (first and second seal members 3 and 4), and the pair of half-hollow molded bodies 1 and 2 The rectangular tube wall 18 of each central partition wall 13 of the hollow molded bodies 1 and 2 is sandwiched from both sides by a secondary molding resin (the flanges 81 and 82 of the coupling member 5), thereby joining the pair of semi-hollow molded bodies 1 and 2 Are joined. Thereby, compared with the conventional technique (conventional example 3) which joins only the outer periphery part of a pair of semi-hollow bodies 130 and 140 by secondary molding resin, joining of the junction part of a pair of semi-hollow molded objects 1 and 2 is carried out. Strength can be improved.

Moreover, since the joint strength of the joint part of a pair of semi-hollow molded objects 1 and 2 can be improved, it is not necessary to increase the injection pressure or the resin pressure when the molten resin is injected and filled in the secondary molding step. As a result, the secondary molding resin (molten resin) injected and filled in a molten state in the injection molding die for secondary molding is unlikely to leak to the bypass flow path side, so that the air flow flowing through the bypass flow paths 21 and 22 is reduced. The flow velocity does not decrease and the air is not disturbed. Therefore, since the measurement error of the air flow rate becomes small, the measurement accuracy of the air flow rate can be improved as the AFM.
Moreover, since the joint strength of the joint part of a pair of semi-hollow molded objects 1 and 2 can be improved, a defect such as deformation of the joint part of the pair of semi-hollow molded bodies 1 and 2 (a gap between the joint end faces of the joint part) It is possible to suppress the occurrence of defects such as being formed or having a step between the joints.

Further, in the injection mold for secondary molding, the fitting convex portion 73 of the second outer partition wall 12 of the semi-hollow molded body 1 and the fitting concave portion 74 of the second outer partition wall 12 of the semi-hollow molded body 2 are fitted. Match. Further, the fitting convex portion 75 of the central partition wall 13 of the semi-hollow molded body 1 and the fitting concave portion 76 of the central partition wall 13 of the semi-hollow molded body 2 are fitted.
As a result, a labyrinth-shaped gap having an uneven shape is formed between the joining end faces of the second outer partition walls 12 and the central partition wall 13 of the pair of semi-hollow molded bodies 1 and 2. As a result, the air flowing through the bypass channels 21 and 22 does not easily pass through the gap formed between the joining end surfaces of the second outer partition walls 12 and the central partition wall 13. Accordingly, it is possible to improve the sealing performance for hermetically sealing the gap formed between the joining end faces of the second outer partition walls 12 and the central partition wall 13.

Further, in the injection molding die for secondary molding, the fitting concave portion 74 of the second outer partition wall 12 of the semi-hollow molded body 2 is fitted into the fitting convex portion 73 of the second outer partition wall 12 of the semi-hollow molded body 1, By fitting the fitting concave portion 76 of the central partition wall 13 of the semi-hollow molded body 2 into the fitting convex portion 75 of the central partition wall 13 of the semi-hollow molded body 1, the joint portions of the pair of semi-hollow molded bodies 1 and 2 are combined. By doing so, it is possible to position the joining end surfaces of the second outer partition walls 12 and the central partition wall 13 of the pair of semi-hollow molded bodies 1 and 2, thereby suppressing the displacement of the bypass flow paths 21 and 22. it can.
Moreover, since it is possible to suppress the positional deviation between the joining end surfaces of the joining portions of the pair of semi-hollow molded bodies 1 and 2, the secondary molding resin that is injected and filled in a molten state in an injection molding die for secondary molding. Since (molten resin) is less likely to leak to the bypass flow path side, the flow velocity of the air flow flowing through the bypass flow paths 21 and 22 does not decrease and the air is not disturbed. Therefore, since the measurement error of the air flow rate is reduced, the AFM measurement accuracy (air flow rate measurement accuracy) can be improved.

  Further, each central partition wall 13 of the pair of semi-hollow molded bodies 1 and 2 has a rectangular tube wall 18 in which a through hole 17 is formed. The opening end surface of the rectangular tube wall 18 is formed at a position recessed from the opening end surface of the central partition wall 13 toward the joining end surface side of the central partition wall 13. As a result, the opening end face of the rectangular tube wall 18 is recessed closer to the joining end face side of the central partition wall 13 than the opening end face of the central partition wall 13, so that the secondary molding resin (injection filling into the flange molding spaces 93 and 94) It is possible to suppress a problem that the flanges 81 and 82) of the coupling member 5 protrude outward from the opening end surface of the central partition wall 13, that is, the outer surfaces of the pair of semi-hollow molded bodies 1 and 2. In this case, when an AFM having a hollow molded body is installed in the intake duct 19 of the engine E, the intake air that flows through the outside of the hollow molded body of the AFM toward the combustion chamber of each cylinder of the engine E is projected (conventionally). It is not disturbed by the joint portions 131 and 141) of the third example. For example, since the air flow rate when the throttle valve 24 is fully opened becomes a flow rate as required by the engine E, the performance of the engine E (for example, engine output) decreases. Can be suppressed.

  10 and 11 show Example 2 of the present invention. FIG. 10 shows an air flow meter (AFM). FIG. 11 shows a hollow molded body constituting a hollow module housing. FIG.

  Here, in each of the semi-hollow molded bodies 1 and 2 of the AFM of the first embodiment, a pair of air enclosing the periphery of the air inlet (inlet part of the hollow part, inlet part of the bypass channel 21) 51 of the bypass channel 21. A half-cylindrical nozzle (hereinafter referred to as an air introduction nozzle) 64 is formed. The pair of air introduction nozzles 64 is provided in the upstream portion of the streamlined hood covers 55 and 56 in the air flow direction. For this reason, the pair of air introduction nozzles 64 are respectively formed with convexly curved outer wall surfaces (hereinafter referred to as curved surface portions) 65 (see FIGS. 2, 3 and 6).

However, as in the AFM of the first embodiment, when the outer wall surface of each air introduction nozzle 64 of the semi-hollow molded bodies 1 and 2 has a curved shape, that is, each air introduction nozzle 64 is provided with a curved portion 65. A pair of molds constituting an injection mold for secondary molding cannot be firmly pressed from both sides. As a result, the air is introduced into the first and second filling grooves 15 and 16 for filling the secondary molding resin injected and filled in the molten state into the injection molding die for secondary molding, that is, the molten resin at the time of the secondary molding. It cannot be extended to the vicinity of the upstream end of the nozzle 64.
Therefore, the joining end surfaces of the pair of air introduction nozzles 64 are not welded, and there is a problem that the joining strength between the pair of air introduction nozzles 64 becomes weak. Even if the first and second filling grooves 15 and 16 are arranged up to the vicinity of the upstream end of each air introduction nozzle 64, injection is performed in a molten state into an injection mold for secondary molding by molding pressure at the time of secondary molding. There is a possibility that the filled secondary molding resin leaks out to the bypass flow path side.

  At this time, burrs may be generated so as to protrude into the bypass channels 21 and 22. In this case, the flow of air flowing through the bypass channels 21 and 22 is disturbed by the burr. In addition, the measurement value in the sensing unit 61 of the thermal flow sensor 6 varies depending on the presence or absence of burrs, the size of the burrs, and the like, resulting in a problem that the AFM measurement accuracy (air flow measurement accuracy) decreases. Further, in the case of a hollow molded body having a weak joint strength at the joint portion of the pair of air introduction nozzles 64, there is a risk that peeling or turning will occur on the joint end surfaces of the air introduction nozzles 64 of the semi-hollow molded bodies 1 and 2. . In this case, since the quality of the hollow molded body is lowered and the aesthetic appearance is deteriorated, the defect rate is increased and the productivity is lowered.

Therefore, for the purpose of improving the joint strength of the joint portions of the air introduction nozzles 64 of the semi-hollow molded bodies 1 and 2, the joint portions of the pair of semi-hollow molded bodies 1 and 2 injection-molded with the primary molding resin are used. In a manufacturing method for obtaining a hollow molded body (hollow module housing) in which hollow portions (bypass channels 21 and 22) are formed inside by joining (welding) with a molten resin that is a secondary molding resin, A planar outer wall surface (hereinafter referred to as a plane portion) 66 is provided in a part of the air introduction nozzle 64.
The flat portion 66 is a flat outer wall surface parallel to the flow direction of the air flowing through the bypass channel 21.
The second filling grooves 16 of the pair of semi-hollow molded bodies 1 and 2 are formed from the U-shaped portion 77 and the end of the U-shaped portion 77 on the bypass flow channel 21 side toward the air inlet 51 side. And an extended portion 78 extended. The extension portion 78 extends from the end of the U-shaped portion 77 on the bypass flow channel 21 side to the vicinity of the tip surface of the air introduction nozzle 64 in the vicinity of the flat portion 66. The extended portions 78 of the pair of semi-hollow molded bodies 1 and 2 open at the joining end face of the air introduction nozzle 64 and communicate with each other.
The space surrounded by the first and second filling grooves 15 and 16 of the semi-hollow molded body 1 and the first and second filling grooves 15 and 16 of the semi-hollow molded body 2 is secondary during the secondary molding step. A secondary flow path is formed in which the molding resin is injected and filled.

  As described above, in the AFM of the present embodiment, a plane having a planar shape parallel to the flow direction of the air flowing through the bypass passage 21 is formed in a part of each air introduction nozzle 64 of the semi-hollow molded bodies 1 and 2. By providing the portion 66, the secondary flow path (particularly the second filling groove 16) in which the secondary molding resin is injected and filled in the secondary molding step is arranged (formed) longer by the length of the extension portion 78. Therefore, the joint strength of the joint part of the pair of air introduction nozzles 64 can be increased. As a result, the secondary molding resin (molten resin) injected and filled in a molten state in the injection molding die for secondary molding is less likely to leak to the bypass flow path 21 side due to molding pressure during secondary molding. The flow velocity of the airflow flowing through the bypass passages 21 and 22 does not decrease or the air is not disturbed. Therefore, since the measurement error of the air flow rate is reduced, the AFM measurement accuracy (air flow rate measurement accuracy) can be improved.

Further, since the joint strength of the joint portion of the pair of air introduction nozzles 64 can be improved as compared with the first embodiment, no burrs are generated so as to protrude into the bypass channels 21 and 22. Thereby, the flow of the air which flows through the bypass flow paths 21 and 22 is not disturbed by the burr. Further, the measurement value in the sensing unit 61 of the thermal flow sensor 6 does not vary depending on the presence or absence of burrs, the size of burrs, and the like. Therefore, the measurement accuracy of AFM (measurement accuracy of air flow rate) can be improved.
Further, since the joint strength of the joint portion of the pair of air introduction nozzles 64 can be improved as compared with the first embodiment, the joining end surface of the air introduction nozzle 64 does not peel or turn up. As a result, the quality of the hollow molded body can be improved and the aesthetic appearance is also improved, so the defect rate is reduced. Therefore, the productivity of AFM can be improved.

  In the present embodiment, a pair of semi-hollow molded bodies 1 and 2 of the AFM are provided with a pair of half-cylinder-shaped air introduction nozzles 64 that surround the periphery of the air inlet 51 of the bypass channel 21, and this air introduction A planar portion 66 having a planar shape parallel to the flow direction of the air flowing through the bypass flow passage 21 is provided in a part of the nozzle 64, but the air flow outlet of the bypass flow passage 21 (the outlet portion of the hollow portion, the bypass) A pair of halved cylindrical air outlet nozzles surrounding the periphery of the outlet portion 52 of the flow path 21 is provided, and a part of the air outlet nozzle is parallel to the flow direction of the air flowing through the bypass flow path 21. A planar outer wall surface (planar portion) may be provided.

[Modification]
In this example, a method for producing a hollow body having a hollow portion formed therein, and a method for producing a synthetic resin hollow body (AFM module housing) having hollow portions (bypass channels 21 and 22) formed therein. Applied to the manufacturing method of a hollow body with a hollow part formed therein, and manufacturing of a synthetic resin hollow body (intake duct and other sensor housings) with a hollow part (intake passage) formed therein It may be applied to the method.

In this embodiment, the flow rate measuring device of the present invention is applied to an air flow rate measuring device that detects the flow rate of air supplied to the combustion chamber of the internal combustion engine (engine) and the air flow direction. The flow rate measuring device may be applied to a flow rate measuring device that detects a flow rate of a fluid such as a gas supplied to a gas appliance or a gaseous fuel or a liquid fuel supplied to a combustion chamber of an internal combustion engine (engine).
Although the temperature sensor resistor is not affected by the heat of the heater resistor and is placed in a place where the temperature of the surrounding air is detected, the temperature sensor resistor has a temperature distribution generated by the heat of the heater resistor. You may form on the membrane of a sensor chip so that it may be located in the downstream of a heater resistor, or both upstream and downstream sides so that it can detect.

  In this embodiment, a heating resistor formed in a predetermined pattern on the surface of a silicon substrate (circuit board) is used as a flow measuring element, but a cylindrical bobbin is inserted as a flow measuring element at both ends of this bobbin. A pair of lead wires to be formed, a resistance wire wound around the outer periphery of the bobbin and connected to the lead wire, and a heating resistor configured to protect the resistance wire and the lead wire may be used. Further, as the protective film, for example, a glass coating film containing lead oxide that is fired at a high temperature may be used.

  In this embodiment, a synthetic resin (thermoplastic resin) such as polybutylene terephthalate (PBT) is used as a primary molding resin for molding a hollow molded body and a secondary molding resin. Synthetic resin (thermoplastic resin) such as polyphenylene sulfide (PPS) or polyethylene terephthalate (PET) or polyphthalamide (PPA) or synthetic resin such as unsaturated polyester (UP) (thermosetting) Resin).

In the present embodiment, an I-shape in which a part of the intake air flowing through the intake duct 19 (intake passage 34) flows into the hollow molded body (between the inner wall surfaces of the pair of semi-hollow molded bodies 1 and 2). The bypass flow path 21 and the U-shaped bypass flow path 22 are formed, but inside the intake duct 19 (intake air) inside the hollow molded body (between the inner wall surfaces of the pair of semi-hollow molded bodies 1 and 2). Only a U-shaped or e-shaped bypass flow path into which a part of the intake air flowing through the passage 34) flows may be formed.
In this embodiment, in the primary molding step, the pair of semi-hollow molded bodies 1 and 2 are integrally formed so as to have different shapes (plane symmetry shapes). The semi-hollow molded bodies 1 and 2 may be integrally formed so as to have the same shape.
Further, a pair of rectifying walls (rectifying portions) for rectifying the air flow flowing from the bypass channel 21 to the bypass channel 22 may be provided in the pair of semi-hollow molded bodies 1 and 2. These rectifying walls may be provided in the inclined channel of the bypass channel 22. In this case, you may provide so that it may protrude toward the joining end surface side of a rectification | straightening wall from each flow-path groove bottom face of the bypass flow path 22. FIG.

1 Semi-hollow molded body (half-hollow body on one side, primary molding material, primary molding resin)
2 Semi-hollow molded body (the other half-hollow body, primary molding material, primary molding resin)
3 First seal member (secondary molding material, secondary molding resin)
4 Second seal member (secondary molding material, secondary molding resin)
5 Bonding member (secondary molding material, secondary molding resin)
6 Thermal flow sensor 11 First outer partition (outer partition on one side, outer partition on the other side)
12 Second outer partition (outer partition on one side, outer partition on the other side)
13 Central bulkhead (Central bulkhead on one side, Central bulkhead on the other side)
15 First filling groove (secondary flow path)
16 Second filling groove (secondary flow path)
17 Through hole 18 Square tube wall 19 Air intake duct 21 I-shaped bypass channel (hollow part)
22 U-shaped bypass channel (hollow part)
34 Intake passage 64 Air introduction nozzle (half-divided cylindrical nozzle)
66 Plane part (outer wall surface) of air introduction nozzle
71 1st protrusion 72 2nd protrusion 73 Fitting convex part 74 Fitting concave part 75 Fitting convex part 76 Fitting concave part 78 Extension part (filling groove)
93 Flange forming space 94 Flange forming space

Claims (18)

In the method for producing a hollow body, a hollow body having a hollow portion formed therein is produced by joining a joint portion of a pair of semi-hollow bodies formed of a primary molding material with a secondary molding material.
The joint part of the pair of semi-hollow bodies has an outer partition that is installed on the outer side of the hollow part, and a central partition that is installed on the inner side of the hollow part,
The manufacturing process for manufacturing the hollow body includes:
A primary molding step of molding the pair of semi-hollow bodies with the primary molding material so as to have the joint portion;
In the state where the joint end surfaces of the joints are in contact with each other, the secondary partition is fused and fixed with the secondary molding material, and the secondary partition is placed in the secondary molding mold so as to sandwich the central partition. A secondary molding step of injecting and filling a molten material to be a molding material and joining the joint,
Each of the pair of semi-hollow bodies has a through-hole penetrating the central partition,
The through hole is opened at the joint end surface of the central partition wall, and is opened at the opening end surface opposite to the joint end surface side of the central partition wall ,
A method for manufacturing a hollow body, characterized in that a secondary flow path in which a molten material serving as the secondary molding material is injected and filled is formed at a joint between the pair of semi-hollow bodies . In the manufacturing method of the hollow body of Claim 1,
The method for producing a hollow body, wherein the secondary molding material is a secondary molding resin that is injected and filled in a molten state in the mold for secondary molding. In the manufacturing method of the hollow body of Claim 1 or Claim 2,
The mold for secondary molding has a molding surface that forms a molding space having a diameter larger than that of the through-hole between the opening end surface of the central partition and the hollow body. Method. In the manufacturing method of the hollow body of Claim 1 or Claim 2,
The central partition wall has a cylindrical wall so as to surround the through hole,
The hollow body manufacturing method, wherein the opening end surface of the cylindrical wall is formed at a position recessed toward the joining end surface side of the central partition wall relative to the opening end surface of the central partition wall. In the manufacturing method of the hollow body of Claim 4,
The secondary molding die has a molding surface that forms a molding space having a diameter larger than that of the through-hole between the opening end surface of the cylindrical wall and the hollow body. Method. In the manufacturing method of the hollow body as described in any one of Claims 1 thru | or 5,
Each of the pair of semi-hollow bodies has a filling groove that opens at a joint end surface of the outer partition wall and communicates with each other;
The method for producing a hollow body , wherein, in the secondary molding step, the secondary molding material is filled into the filling groove and the outer partition wall is fused and fixed . In the manufacturing method of the hollow body of Claim 6 ,
The method for producing a hollow body, wherein the outer partition wall has a protrusion protruding from the groove wall surface of the filling groove toward the joining end surface side of the outer partition wall . In the manufacturing method of the hollow body according to any one of claims 1 to 7 ,
A method for producing a hollow body, wherein a gap of a labyrinth structure having an uneven shape or a bent shape is formed on a joining end face of the outer partition wall. In the manufacturing method of the hollow body according to any one of claims 1 to 8,
A method for producing a hollow body, wherein a gap of a labyrinth structure having an uneven shape or a bent shape is formed on a joint end face of the central partition wall . In the manufacturing method of the hollow body according to any one of claims 1 to 9,
The outer partition wall includes an outer partition wall on one side formed at a joint portion of one half hollow body of the pair of semi-hollow bodies, and a semi-hollow body on the other side of the pair of semi-hollow bodies. Having an outer partition on the other side formed at the joint,
A fitting recess is formed on the joint end surface of the outer partition on the one side,
The manufacturing method of the hollow body characterized by the fitting convex part which fits in the said fitting recessed part being formed in the joining end surface of the said outer side partition on the said other side . In the manufacturing method of the hollow body according to any one of claims 1 to 10,
The central partition is formed of a central partition on one side formed at a joint of one half hollow body of the pair of semi-hollow bodies, and a semi-hollow body on the other side of the pair of semi-hollow bodies. Having a central partition on the other side formed at the joint,
A fitting recess is formed on the joint end surface of the central partition on the one side,
A fitting convex portion that fits into the fitting concave portion is formed on the joint end surface of the other central partition wall . In the manufacturing method of the hollow body according to any one of claims 1 to 11,
The pair of semi-hollow bodies each have a pair of half-tubular nozzles surrounding the inlet portion or the outlet portion of the hollow portion,
The pair of half-divided cylindrical nozzles each have a planar outer wall surface . In the manufacturing method of the hollow body according to claim 12 ,
A method for producing a hollow body, characterized in that a secondary flow path is formed on a joining end face of the pair of half-cylindrical nozzles, in which a molten material serving as the secondary molding material is injected and filled . In the manufacturing method of the hollow body of Claim 12 or Claim 13,
The pair of semi-hollow bodies each have a filling groove that opens at a joint end surface of the pair of half-tubular nozzles and communicates with each other;
A method for producing a hollow body , wherein, in the secondary molding step, the secondary molding material is filled into the filling groove and the pair of half-tubular nozzles are fused and fixed . A hollow body manufactured by the manufacturing method according to any one of claims 1 to 14 . A method for producing a flow rate measuring device, comprising producing a flow rate measuring device comprising the hollow body according to claim 15 . In the flow measuring device comprising the hollow body according to claim 15 ,
A flow rate measuring apparatus comprising a flow rate sensor installed inside the hollow body . The flow rate measuring device according to claim 17 ,
The inside of the hollow body is a bypass flow path into which a part of the air flowing through the intake passage of the internal combustion engine flows,
The flow rate sensor has a flow rate measuring element for measuring a flow rate of air flowing through the bypass flow path .

Images