JP2006150875A - Manufacturing method of throttle device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make it possible to carry out the injection molding of a throttle valve 3 almost simultaneously in the same injection mold as that of a throttle body 1 without using a core-back method and the necessity of advanced mold adjustment technique and advanced mold working technique. <P>SOLUTION: An insert core 2 is set in the inside of an injection mold so that a body cavity 57 and a valve cavity 58 may be divided off. A bore internal diameter surface 33 of the insert core 2 is used as a part of the injection mold which forms a periphery side end surface 35 of the throttle valve 3, thereby the shape of a periphery side end surface of the throttle valve 3 is injection-molded to the shape imitated with the shape of a bore internal diameter surface shape of the insert core 2. Therefore, the clearance dimension between the bore internal diameter surface 33 of the insert core 2 and the periphery side end surface 35 of the throttle valve 3 becomes highly precise, and the leakage air volume at the time of the totally-enclosed throttle valve 3 easily becomes on-target air volume also with high precision. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method of manufacturing a throttle device for an internal combustion engine mounted on a vehicle such as an automobile, and more particularly to an internal combustion engine capable of forming a throttle body and a throttle valve substantially simultaneously in the same molding die. The present invention relates to a method for forming a throttle device.

[Conventional technology]
In recent years, a throttle device for an internal combustion engine in which a throttle body and a throttle valve are both made of resin has been proposed for the purpose of reducing fuel consumption, reducing weight, and reducing costs. Conventionally, in a throttle device for an internal combustion engine in which the valve angle of a throttle valve is changed in accordance with the amount of depression of an accelerator pedal by a vehicle occupant, the inner diameter surface (bore of the throttle bore) formed in the throttle body. It is known that a gap formed between the inner diameter surface) and the outer peripheral side end face of the throttle valve has a great influence on the amount of leakage air when the throttle valve is fully closed.

  In the conventional throttle device for an internal combustion engine, in order to control the clearance between the bore inner diameter surface of the throttle body and the outer end surface of the throttle valve with high accuracy, the bore inner diameter surface of the throttle body as a molded product is A core back molding method used as a part of a molding die for molding an end face is known (see, for example, Patent Document 1). Also, fine adjustment of the molding die to increase the accuracy of the clearance between the bore inner diameter surface of the throttle body and the outer peripheral end surface of the throttle valve, or the method of making the throttle valve separately and then assembling the throttle body later Has been proposed and put to practical use.

[Conventional technical problems]
However, in the core back molding method described in Patent Document 1, since the throttle valve is molded after the throttle body is molded, there is a problem that the cycle time becomes slow and the productivity is poor. In addition, when the throttle body and the throttle valve are resin-molded with the same resin material, there is a possibility that the outer peripheral side end face of the throttle valve may be caught on the bore inner diameter face of the throttle body. Moreover, since the accuracy of the roundness of the throttle bore is not good, there is a problem that the roundness of the throttle valve is poor.
In addition, the method of finely adjusting the molding die to increase the accuracy is not a method that can be applied anywhere such as an overseas base because it requires advanced die adjustment technology and advanced die processing technology.
In addition, there is a problem in that an additional cost is required for a method of making the throttle valve as a separate body and later assembling the throttle valve on the throttle body.

Here, a structure in which a metal insert is fitted into a cylindrical groove of a resinized throttle body has been proposed (see, for example, Patent Document 2).
However, the throttle body described in Patent Document 2 uses a metal insert with good thermal conductivity to prevent icing caused by the low thermal conductivity of the resin, and the throttle bore with heat from the engine coolant. This is to prevent the inside from freezing. Therefore, since the purpose of molding the throttle body and the throttle valve in the same molding die is not the same, the desired product cannot be obtained as it is.

The reason is that if the throttle valve is molded simultaneously with the throttle body, it is necessary to insert the molding die into the metal insert, but if the minute gap (clearance) between the metal insert and the molding die is narrowed, There is a problem that the molding die is galling on the inner peripheral surface of the metal insert and scratches the inner peripheral surface of the metal insert. Conversely, if the clearance between the metal insert and the molding die is widened, the resin material enters the clearance when heated and injected into the molding die with a molten resin material, There is a problem that a large burr is formed on the outer peripheral side end face of the throttle valve.
Japanese Patent No. 3315135 (page 1-7, FIGS. 1-7) Japanese Utility Model Publication No. 6-49756 (page 1-2, FIGS. 1 to 3)

  An object of the present invention is to provide a throttle for an internal combustion engine in which a throttle body and a throttle valve can be injection-molded substantially at the same time in the same molding die without requiring advanced die adjustment technology and advanced die machining technology. It is to provide a method for manufacturing an apparatus.

  According to the first aspect of the present invention, the insert core is set in a molding die (for example, an injection molding die), and the cavity formed in the molding die is shaped corresponding to the product shape of the throttle body. The body cavity and the valve cavity having a shape corresponding to the product shape of the throttle valve are divided into at least two parts. Then, the bore inner surface of the insert core is used as a part of a molding die that forms the outer peripheral end surface of the throttle valve, and a molten resin material is injected and filled into the body cavity and the valve cavity. As a result, the throttle body and the throttle valve are injection-molded almost simultaneously in the same molding die without the need for advanced mold adjustment technology and advanced mold processing technology, and the insert core is placed inside the throttle body. Is insert molded.

  At this time, the outer peripheral side end face of the throttle valve is formed in a shape that follows the inner diameter dimension of the insert core, so the clearance dimension between the bore inner diameter face of the insert core and the outer peripheral side end face of the throttle valve becomes high accuracy, and the throttle valve The amount of air leaked when the valve is fully closed can be easily achieved with high accuracy. In addition, since the throttle body and the throttle valve can be injection-molded substantially simultaneously, the cycle time can be shortened and the productivity can be improved. Further, a throttle device for an internal combustion engine in which the throttle body and the throttle valve are made of resin and an insert core is insert-molded inside the throttle body can be manufactured without requiring assembly costs.

  According to the second aspect of the present invention, the first resin injection port for injecting the molten resin material into the body cavity and the second resin for injecting the molten resin material into the valve cavity are formed in the molding die. By providing the injection port independently of each other, the throttle valve can be independently moved without post-processing after removing the runner even in the same molding die and injection molding at the same time. In addition, since an insert core is provided at the boundary surface between the body cavity of the molding die and the valve cavity of the molding die, the molten resin material injected from the first resin inlet and the second resin injection. Even if the molten resin material injected from the inlet is the same resin material, it will not be caught, and there will be fewer defective products such as throttle body molding defects and throttle valve molding defects, The defective rate of the throttle device for an internal combustion engine in which both the throttle body and the throttle valve are made of resin can be reduced.

  According to the invention described in claim 3, the annular gap formed between the bore inner surface of the insert core and the outer periphery of the movable mold is temporarily wide, and the interior of the insert core is movable in the direction of the central axis of the circular space. When the cylinder is moved, the annular gap is sealed by the sealing material, so that the molten resin material does not enter the annular gap from the valve cavity of the molding die, and a large burrs are formed on the outer peripheral end face of the throttle valve. Is not formed. In addition, if the annular gap formed between the bore inner surface of the insert core and the outer periphery of the movable mold is narrow, and the movable mold is moved in the center axis direction of the circular space within the insert core, the sealing member Since it is formed of a material softer than the bore inner surface of the insert core, the sealing material does not damage the bore inner surface of the insert core.

  According to the invention described in claim 4, when an insert core is set in a molding die (for example, an injection molding die) and the throttle valve is molded almost simultaneously with the throttle body, the material does not deform due to heat or pressure ( For example, if the insert core is formed of metal material, ceramics, resin material, etc., and the inner diameter dimension of the bore inner diameter surface of the insert core is processed with high accuracy in advance before setting the insert core in the molding die, Since the outer peripheral end face shape of the throttle valve is formed so as to follow the bore inner face shape of the insert core, the roundness of the throttle valve can be ensured with high accuracy.

  According to the invention described in claim 5, the throttle valve is integrally assembled with a throttle shaft having a rotation center axis in a direction substantially orthogonal to the center axis direction of the throttle bore of the throttle body. For example, the throttle shaft is insert-molded inside the throttle valve. One end portion or both end portions of the throttle shaft in the rotational center axis direction are installed so as to protrude from the outer peripheral end surface of the throttle valve toward the insert core. And the through-hole which the one end part or both ends of a throttle shaft penetrates in the insert core is provided.

  According to the sixth aspect of the present invention, the inner periphery of the through-hole of the insert core has a sliding hole that supports one end or both ends of the throttle shaft in the rotational center axis direction so as to be slidable in the rotational direction. The bearing member is press-fitted and fitted. The bearing member is press-fitted into the inner periphery of the through hole of the insert core before substantially simultaneous molding of the throttle body and the throttle valve, and when the insert core is set in the molding die, the molding die A bearing member may also be set in (for example, an injection mold). Further, the bearing member may be press-fitted and fitted to the inner periphery of the through hole of the insert core after substantially simultaneous molding of the throttle body and the throttle valve. Thus, the coaxiality between the center axis of the through hole of the insert core or the center axis of the sliding hole of the bearing member and the rotation center axis of the throttle shaft can be ensured with high accuracy.

  According to invention of Claim 7, the insert core is formed with the bearing material which is excellent in abrasion resistance. The through hole functions as a sliding hole that pivotally supports one end or both ends of the throttle shaft in the rotation center axis direction so as to be slidable in the rotation direction. As a result, it is not necessary to press-fit the bearing member to the inner periphery of the through hole of the insert core, and the assembling cost can be reduced. Further, the coaxiality between the center axis of the through hole of the insert core and the rotation center axis of the throttle shaft can be ensured with high accuracy.

  The best mode for carrying out the present invention is that the throttle body and the throttle valve are injection-molded substantially at the same time in the same molding die without requiring advanced die adjustment technology and advanced die machining technology. The object was achieved by setting the insert core in the mold and molding the throttle valve using the insert core as part of the mold.

[Configuration of Example 1]
1 and 2 show a first embodiment of the present invention. FIG. 1 shows a schematic structure of an injection mold, and FIG. 2 (a) shows a main structure of a throttle device for an internal combustion engine. FIG. 2B is a view showing the insert core.

  The throttle device for an internal combustion engine of the present embodiment includes a throttle body 1 that communicates with each cylinder (cylinder) of an internal combustion engine (hereinafter referred to as an engine) such as a gasoline engine, and an insert core that is insert-molded inside the throttle body 1. 2, a throttle valve 3 for adjusting the flow rate of intake air flowing in the throttle body 1 and the insert core 2, and a power unit as a valve driving means for rotationally driving the throttle valve 3 in the valve opening direction (or valve closing direction) (Not shown), a return spring 5 as valve urging means for urging the throttle valve 3 in the valve closing direction (or valve opening direction), and the throttle valve 3 according to the accelerator operation amount of the driver (driver). Engine control device (engine control unit: It is provided with a call) and the ECU.

  The power unit of the present embodiment includes a drive motor (not shown) as a power source and a gear reduction mechanism that reduces the rotational speed of the drive motor to a predetermined reduction ratio. Has been. Here, the ECU opens the accelerator opening sensor that converts the accelerator operation amount (accelerator pedal depression amount) by the driver into an electric signal (accelerator opening signal) and outputs to the ECU how much the accelerator pedal is depressed. (Not shown) is connected. The throttle device for an internal combustion engine converts the valve opening (rotation angle) of the throttle valve 3 into an electrical signal (throttle opening signal) and outputs to the ECU how much the throttle valve 3 is open. It has a sensor (throttle position sensor: not shown). The ECU feedback-controls the control signal to the drive motor so that there is no deviation between the throttle opening signal output from the rotation angle sensor and the accelerator opening signal output from the accelerator opening sensor.

  Here, the rotation angle sensor is a split permanent magnet (magnet) that is a magnetic field generation source attached to one end or the other end of the throttle shaft 4 to be described later, and an inner periphery of a split yoke magnetized by the magnet. A non-contact detection element (for example, a Hall element, a Hall IC, a magnetoresistive element, etc.) that is disposed to face the surface and receives the magnetic force of the magnet to detect the rotation angle of the throttle valve 3 is configured. The rotation angle sensor is integrally arranged on a sensor cover (not shown) assembled to the outer wall portion of the throttle body 1. Moreover, the magnet and the yoke are fixed to the inner peripheral surface of the valve gear 6 which is one of the components of the gear reduction mechanism by using an adhesive.

  Here, the gear reduction mechanism is engaged with a pinion gear (not shown) fixed to the motor shaft of the drive motor, an intermediate reduction gear (not shown) rotating in mesh with the pinion gear, and rotating in mesh with the intermediate reduction gear. And is used as a power transmission mechanism that transmits the rotational power of the drive motor to the throttle shaft 4. The valve gear 6 is integrally formed in a predetermined substantially annular shape, for example, by a resin material, and a gear portion (toothed portion) 11 that meshes with the intermediate reduction gear is integrally formed on the outer peripheral surface of the valve gear 6. Has been. Further, a fully closed stopper portion (not shown) that is locked to the fully closed stopper when the throttle valve 3 is closed to the fully closed position is integrally formed on the outer peripheral portion of the valve gear 6. In addition, you may integrally form in the outer peripheral part of the valve gear 6 the full open stopper part latched by a full open stopper when the throttle valve 3 opens to a full open position.

  A return spring 5 is mounted in a cylindrical portion 12 that is integrally formed so as to protrude from the bore wall side surface (body side surface) of the valve gear 6 toward the left in the figure. The return spring 5 is a coil spring mounted on the outer peripheral side of the throttle shaft 4. One end of the return spring 5 is held by a body side hook (not shown) provided on the outer wall surface of the cylindrical portion 13 of the throttle body 1, that is, the bottom wall surface of the gear box portion (not shown). The other end of the return spring 5 is held by a gear-side hook (not shown) provided on the bore wall side surface (body side surface) of the valve gear 6.

  The throttle body 1 of the present embodiment accommodates a throttle valve 3 in an openable and closable manner, and has a cylindrical portion (throttle bore wall portion) 13 through which intake air sucked into each cylinder of the engine flows in the central axis direction. The throttle housing is formed with a circular throttle bore 14 in which the intake air (air) toward the engine flows in the cylindrical portion 13, and the throttle valve 3 is moved from the fully closed position to the fully open position in the throttle bore 14. It is a device that holds it rotatably in the rotational direction until it is tightened and fixed to the intake manifold of the engine using a fastener (not shown) such as a fixing bolt or a fastening screw. In the present embodiment, the intake air filtered by the air cleaner flows into the throttle bore 14 from the upper side of the figure via the intake pipe, and passes through the intake manifold connected to the lower side of the throttle body 1 in the figure. The cylinder is configured to be sucked into the cylinder.

  Here, the cylindrical portion 13 of the throttle body 1 of the present embodiment is made of a resin material such as a thermoplastic resin (for example, polyphenylene sulfide: PPS, or polybutylene terephthalate: PBT, or polyamide resin: PA, or polypropylene: PP, or Polyetherimide: heat-resistant resin such as PEI) is injected into an injection mold so as to be integrally formed into a substantially circular tube shape. The cylindrical portion 13 of the throttle body 1 is resin-molded so as to have substantially the same inner diameter and outer diameter over the flow direction of intake air (the direction from the upper end side in the figure toward the lower end side in the figure).

  In addition, the first and second valve bearing portions 15 and 16 that rotatably support the first and second bearing sliding portions at both ends of the throttle shaft 4 are integrated with the cylindrical portion 13 of the throttle body 1 by resin molding. Is formed. The first and second valve bearing portions 15 and 16 are provided with first and second shaft through holes 21 and 22 having round holes. In the present embodiment, the outer wall surfaces of the first and second valve bearing portions 15 and 16 are provided so as to be flush with the outer wall surface of the cylindrical portion 13 of the throttle body 1, but the first and second valves You may provide so that the outer wall surface of the bearing parts 15 and 16 may protrude in the both ends side (outside side) of an axial direction rather than the outer wall surface of the cylindrical part 13 of the throttle body 1. FIG. In this case, the first and second valve bearing portions 15 and 16 are formed in a substantially cylindrical shape.

  Further, on the outer wall surface of the cylindrical portion 13 of the throttle body 1, a gear box portion (not shown) for rotatably accommodating each reduction gear of the gear reduction mechanism, and for accommodating and fixing the drive motor therein. A motor housing portion (not shown) and the like are integrally formed (resin integrated molding) by resin molding. In the gear box portion, a fully closed stopper (not shown) for restricting the rotational operation of the throttle valve 3 in the fully closed direction at the fully closed position of the throttle valve 3 is integrally formed by resin molding. . Note that a full-open stopper for restricting the rotation operation of the throttle valve 3 in the fully-open direction at the fully-open position of the throttle valve 3 may be integrally formed in the gear box portion by resin molding. Further, at one end of the cylindrical portion 13 of the throttle body 1, there is a mounting flange portion 23 for fastening the throttle body 1 to an engine intake manifold (or surge tank) with a fastener such as a fixing bolt or a fastening screw. Is provided. Here, a cylindrical fitting groove 24 for fitting the insert core 2 is provided on the inner wall surface of the cylindrical portion 13 of the throttle body 1 of the present embodiment.

  The insert core 2 is a cylindrical body formed of a metal material such as brass or stainless steel, and has a circular space 25 that forms a part of the throttle bore 14 therein. Further, the insert core 2 is provided with first and second shaft through holes 31 and 32 having round hole shapes through which both end portions of the throttle shaft 4 pass. A bore inner wall surface (hereinafter referred to as a bore inner diameter surface) 33 is formed on the inner circumference of the insert core 2, and the fitting groove 24 of the cylindrical portion 13 of the throttle body 1 is formed on the outer circumference of the insert core 2. An outer wall 34 that is in close contact is formed.

  In the present embodiment, the bore inner surface 33 of the insert core 2 is formed by molding (or inner diameter cutting or inner diameter polishing) so that the cross-sectional shape of the circular space 25 of the insert core 2 is a perfect circle. The clearance accuracy with the outer peripheral side end face 35 of the throttle valve 3 is improved. The dimension of the insert core 2 in the central axis direction is such that the outer peripheral side end surface 35 of the throttle valve 3 is located on the bore inner diameter surface 33 of the insert core 2 when the valve angle of the throttle valve 3 is at the fully closed position where the intake air amount is minimized. It is provided in a length that allows direct contact. Further, the thickness of the insert core 2 in the radial direction substantially perpendicular to the central axis direction is such that the outer wall surface 34 of the insert core 2 is not exposed from the outer wall surface of the cylindrical portion 13 of the throttle body 1, and the insert core 2. The bore inner diameter surface 33 is set to a size range that can be held by the core holding portion of the fixed mold 51 and the movable mold 52 described later.

  The throttle valve 3 of the present embodiment is a substantially disk-shaped butterfly type rotary valve having a rotation center axis in a direction substantially orthogonal to the direction of the center axis of the cylindrical portion 13 of the throttle body 1 and is fully opened from the fully closed position. By changing the rotation angle to the position, the amount of intake air taken into each cylinder of the engine is controlled. The throttle valve 3 includes a substantially disc-shaped resin disk (plate-shaped portion) 41, a substantially cylindrical resin shaft (cylindrical portion, shaft-shaped portion) 42, and the like. The resin disk 41 and the resin shaft 42 are made of a resin material such as a thermoplastic resin (for example, polyphenylene sulfide: PPS, or polybutylene terephthalate: PBT, or polyamide resin: PA, or polypropylene: PP, or polyetherimide: PEI). Etc.) are integrally formed so as to have a substantially disc shape by injecting the resin into the injection mold.

  The resin shaft 42 of the throttle valve 3 is integrally formed on the outer periphery of the valve holding portion of the throttle shaft 4 by resin molding. As a result, the throttle valve 3 and the throttle shaft 4 can be integrated and rotated integrally. Further, on the outer periphery of the resin disk 41 of the throttle valve 3, an outer peripheral side end surface 35 having a shape following the shape of the bore inner diameter surface 33 of the insert core 2 is formed. A reinforcing rib (not shown) for reinforcing the resin disk 41 is formed by resin molding on one end surface of the resin disk 41 (for example, the upstream side surface in the flow direction of the intake air flowing through the throttle bore 14) or both end surfaces. You may form integrally.

  The throttle shaft 4 of the present embodiment is a metal shaft (rotary shaft) formed of a metal material such as brass or stainless steel in the shape of a round shaft, and flows in the throttle bore 14 of the cylindrical portion 13 of the throttle body 1. The rotation center axis direction (axial direction) is set in a direction substantially orthogonal to the flow direction of the intake air, that is, in a direction substantially orthogonal to the center axis direction of the insert core 2. Both end portions of the throttle shaft 4 in the axial direction pass through the first and second shaft through holes 31 and 32 of the insert core 2, and further, the first and second shaft through holes 21 of the cylindrical portion 13 of the throttle body 1, 22 is rotatably supported by the first and second valve bearing portions 15 and 16.

  The minimum diameter portion provided near the central portion in the axial direction of the throttle shaft 4 functions as a valve holding portion that holds and fixes the throttle valve 3 and reinforces the resin disk 41 and the resin shaft 42 of the throttle valve 3. Insert molding is performed inside the resin shaft 42. The maximum diameter portion provided on one end side in the rotation center axis direction (axial direction) of the throttle shaft 4 is exposed (protruded) from the annular end surface on one end side of the resin shaft 42 of the throttle valve 3, so that the throttle body 1 It functions as a first bearing sliding portion that slides rotatably on the first valve bearing portion 15 of the cylindrical portion 13. Further, the maximum diameter portion provided on the other end side in the rotation center axial direction (axial direction) of the throttle shaft 4 is a second bearing that slides rotatably on the second valve bearing portion 16 of the cylindrical portion 13 of the throttle body 1. Functions as a sliding part.

  The throttle shaft 4 is disposed between the outer peripheral surface of the first bearing sliding portion of the throttle shaft 4 and the inner peripheral surface of the first shaft through hole 21 of the cylindrical portion 13 of the throttle body 1. An annular gap of about 10 to 20 μm is formed in order to slide freely inside. Further, the throttle shaft 4 is disposed between the outer peripheral surface of the second bearing sliding portion of the throttle shaft 4 and the inner peripheral surface of the second shaft through hole 22 of the cylindrical portion 13 of the throttle body 1. An annular gap of about 10 to 20 μm is formed in order to slide freely inside. And the valve gear 6 which is one of the components of a gear reduction mechanism is assembled | attached to the right end part (other end part) of the throttle shaft 4 shown in figure using fixing means, such as caulking. It should be noted that axial end portions (first and second bearing sliding portions) of the throttle shaft 4 are arranged in the rotational direction on the inner circumferences of the first and second valve bearing portions 15 and 16 of the cylindrical portion 13 of the throttle body 1. A bearing member having a sliding hole that is slidably supported may be press-fitted and fitted.

[Production Method of Example 1]
Next, an injection molding method of the throttle device for an internal combustion engine according to the present embodiment will be briefly described with reference to FIGS.

  The injection mold (resin molding mold) of the present embodiment is mounted on an injection molding machine (not shown), and as shown in FIG. 1, mainly a fixed mold (fixed mold) 51 and this fixed mold. A movable mold (movable mold) 52 is configured so as to be movable back and forth (approach / separate, contact / separate) in the illustrated vertical direction with respect to the mold 51. The fixed mold 51 has a substantially cylindrical fixed mold insert 53 in which, for example, the bore inner diameter of the cylindrical portion 13 of the throttle body 1 and the bore inner diameter of the insert core 2 substantially coincide with each other. The illustrated upper end surface (parting surface, parting line) of the fixed mold insert 53 is located on the downstream side surface of the resin disk 41 of the throttle valve 3 and the resin shaft 42 in the intake air flow direction.

  The movable mold 52 has a substantially cylindrical movable nest 54 in which the bore inner diameter of the cylindrical portion 13 of the throttle body 1 and the bore inner diameter of the insert core 2 substantially coincide with the outer diameter. The illustrated lower end face (parting surface, parting line) of the movable insert 54 is located on the upstream side surface of the resin disc 41 of the throttle valve 3 and the resin shaft 42 in the flow direction of the intake air. In this embodiment, the fixed mold 51 and the fixed mold insert 53 are integrated, but they may be separated. In the present embodiment, the movable mold 52 and the movable insert 54 are integrated, but they may be separated. Furthermore, the fixed mold 51 and the movable mold 52 may be interchanged, or both may be movable molds.

  Further, a split-type slide that is movable between the fixed mold 51 and the movable mold 52 so as to be movable back and forth (approaching / separating and contacting / separating) in the horizontal direction in the figure with respect to the fixed mold 51 and the movable mold 52. Cores 55 and 56 are interposed. These slide cores 55 and 56 are formed in a substantially semi-cylindrical shape, and the inner peripheral surface (parting surface, parting line) has, for example, an outer diameter and an inner diameter dimension of the cylindrical portion 13 of the throttle body 1 substantially equal. I'm doing it. Here, the insert core 2 is fitted in the cylindrical portion 13 of the throttle body 1 when the throttle valve 3 is resin-molded (injection molding) substantially simultaneously with the throttle body 1 in the same injection mold as the throttle body 1. The inner peripheral portion of the insert core 2 is held by a core holding portion (not shown) provided in the injection mold so as to be insert-molded in the joint groove 24. The core holding part is provided in the fixed mold insert 53 of the fixed mold 51 and the movable mold insert 54 of the movable mold 52.

  Further, both axial end portions of the throttle shaft 4 function as first and second bearing sliding portions that are rotatably supported by the first and second valve bearing portions 15 and 16 of the cylindrical portion 13 of the throttle body 1. In addition, the central portion located in the throttle bore 14 of the cylindrical portion 13 of the throttle body 1 functions as a valve holding portion that holds and fixes the resin shaft 42 of the throttle valve 3. Therefore, the throttle shaft 4 is placed inside the resin shaft 42 of the throttle valve 3 when the throttle valve 3 is resin-molded (injection-molded) almost simultaneously with the throttle body 1 in the same injection mold as the throttle body 1. Both end portions in the axial direction of the throttle shaft 4 are held by first and second shaft holding portions (not shown) provided in the injection mold so as to be insert-molded. The first and second shaft holding portions are provided in the fixed mold insert 53 of the fixed mold 51 and the movable mold insert 54 of the movable mold 52.

  In this embodiment, when the injection mold is clamped, the mold splitting surface of the fixed mold 51, the mold splitting face of the movable mold 52, and the outer peripheral surface (mold splitting face) of the fixed mold insert 53 are movable. A shape corresponding to the product shape of the throttle body 1 is formed between the outer peripheral surface (molding surface) of the mold insert 54, the inner peripheral surface (molding surface) of the slide cores 55 and 56, and the outer wall surface 34 of the insert core 2. A body cavity 57 is formed. The body cavity 57 has a shape corresponding to the product shape of the first body cavity and the gear box portion of the throttle body 1 corresponding to the product shape of the cylindrical portion 13 (including the mounting flange portion 23 and the like) of the throttle body 1. The second body cavity and the third body cavity having a shape corresponding to the product shape of the motor housing portion for housing and fixing the drive motor therein.

  Further, in this embodiment, when the injection mold is clamped, the upper end surface (mold splitting surface) of the fixed mold insert 53, the lower end surface (mold splitting surface) of the movable mold insert 54 and the insert core 2 are shown. A valve cavity 58 having a shape corresponding to the product shape of the throttle valve 3 is formed between the bore inner diameter surface 33. The valve cavity 58 includes a first valve cavity having a shape corresponding to the product shape of the resin disc 41 of the throttle valve 3 and a second valve cavity having a shape corresponding to the product shape of the resin shaft 42 of the throttle valve 3. ing.

  Although the first to third body cavities communicate with each other, the first and second valve cavities are partitioned by the insert core 2 from the first to third body cavities. The first to third body cavities and the first and second valve cavities are connected to a resin material supply device (not shown) for supplying a resin material into the injection mold. This resin material supply device is heated and melted in a body cavity 57 for molding the throttle body 1 at the front ends of a plurality of resin flow paths (not shown) for feeding the resin material into the injection mold. One or more body gates (first gate, first resin inlet: not shown) for injecting a resin material (for example, a molten resin made of a thermoplastic resin such as PPS or PBT), and a throttle One or more valve gates for injecting a molten resin material (for example, a molten resin made of a thermoplastic resin such as PPS or PBT) into the valve cavity 58 for molding the valve 3 And a second gate and a second resin injection port (not shown).

  Next, in order to manufacture the throttle device for the internal combustion engine of the present embodiment, that is, for the purpose of converting the throttle body 1 and the throttle valve 3 into resin, the throttle body 1 and the throttle valve 3 are placed in the same injection mold. The injection molding process for injection molding almost simultaneously will be briefly described. First, the insert core 2 and the throttle shaft 4 are set in the injection mold, and the injection mold is clamped (first process, mold clamping process). Thereby, the cavity formed in the injection mold is liquid-tight into the body cavity 57 having a shape corresponding to the product shape of the throttle body 1 and the valve cavity 58 having a shape corresponding to the product shape of the throttle valve 3. It is divided (divided into two).

  Next, the resin material heated and melted is injected into the body cavity 57 and the valve cavity 58 formed by the injection mold from one or more body gates and valve gates, and the body cavity The resin material is filled in 57 and the valve cavity 58 (second step, injection / filling step). At this time, the bore inner diameter surface 33 of the insert core 2 held by the core holding portion of the injection mold is used as a part of the injection mold for molding the outer peripheral side end surface 35 of the resin disk 41 of the throttle valve 3. The

  Next, the resin pressure in the injection mold (resin pressure in the body cavity 57 and the valve cavity 58) is gradually increased to hold the pressure at a resin pressure larger than the maximum resin pressure at the time of injection. That is, a predetermined pressure is applied to the resin material in the injection mold, cooling water is introduced into the injection mold, and the resin material for the shrinkage caused by the cooling water is supplied to one or more body gates. Further, the body cavity 57 and the valve cavity 58 are replenished from the valve gate (pressure holding step).

  Next, the resin material filled in the body cavity 57 and the valve cavity 58 of the injection mold is taken out and cooled to be cured (solidified), or the resin material is cooled in the cavity of the injection mold. Is cooled and cured (solidified), a product-shaped resin molded product in which the throttle valve 3 is rotatably incorporated into the cylindrical portion 13 of the throttle body 1 is manufactured by injection molding of a resin member. At this time, the insert core 2 is insert-molded on the inner periphery of the cylindrical portion 13 of the throttle body 2. The throttle shaft 4 is also insert-molded inside the resin shaft 42 of the throttle valve 3.

  Since the bore inner diameter surface 33 of the insert core 2 is used as a part of an injection mold for molding the outer peripheral side end surface 35 of the resin disk 41 of the throttle valve 3, the outer periphery of the resin disk 41 of the throttle valve 3 is used. The side end face shape follows the bore inner diameter face shape of the insert core 2, and the gap between the bore inner diameter face 33 of the insert core 2 and the outer peripheral side end face 35 of the resin disk 41 of the throttle valve 3 is the minimum required gap, that is, the insert A gap in which the throttle valve 3 can rotate is formed in the circular space 25 of the core 2.

[Operation of Example 1]
Next, the operation of the throttle device for an internal combustion engine according to this embodiment will be briefly described with reference to FIGS.

  When the driver depresses the accelerator pedal, an accelerator opening signal is input to the ECU from the accelerator opening sensor. The drive motor is energized so that the throttle valve 3 has a predetermined throttle opening (rotation angle) by the ECU, and the motor shaft of the drive motor rotates. Then, the torque of the drive motor is transmitted to the pinion gear, the intermediate reduction gear, and the valve gear 6. As a result, the valve gear 6 rotates against the urging force of the return spring 5 by a rotation angle corresponding to the amount of depression of the accelerator pedal (accelerator operation amount). Accordingly, since the valve gear 6 rotates, the throttle shaft 4 rotates at the same rotation angle as that of the valve gear 6, and the throttle valve 3 is rotationally driven in a direction to open from the fully closed position to the fully opened position (fully opened direction). As a result, since the throttle bore 14 formed in the circular space 25 of the insert core 2 is opened by a predetermined rotation angle, the engine rotation speed is changed to a speed corresponding to the accelerator pedal depression amount (accelerator operation amount). Is done.

  Conversely, when the driver removes his / her foot from the accelerator pedal, the throttle valve 3, throttle shaft 4, valve gear 6 and accelerator pedal, etc. are moved to their original positions (idling position, throttle valve 3 fully closed position) by the urging force of the return spring 5. Is returned to. When the driver returns the accelerator pedal, an accelerator opening signal (0%) is output from the accelerator opening sensor, so that the ECU opens the valve opening (valve opening) when the throttle valve 3 is fully closed. The drive motor may be energized to reversely rotate the motor shaft of the drive motor. In this case, the throttle valve 3 can be rotationally driven in the fully closed direction by the drive motor.

  At this time, the throttle valve 3 is fully opened from the fully open position side by the urging force of the return spring 5 until the fully closed stopper portion provided on the valve gear 6 comes into contact with the fully closed stopper resin-molded on the gear box portion of the throttle body 1. It rotates in the closing direction (full closing direction). Further, since the further closing operation of the throttle valve 3 in the fully closed direction is restricted by the fully closed stopper, the throttle valve 3 is held in a predetermined fully closed position in the circular space 25 of the insert core 2. As a result, the throttle bore 14 communicating with each cylinder of the engine is fully closed, and the rotational speed of the engine becomes the idle rotational speed.

[Effect of Example 1]
As described above, in the throttle device for an internal combustion engine of the present embodiment, the throttle valve 3 is injection-molded substantially simultaneously with the throttle body 1 in the same injection mold as the throttle body 1, thereby A resin molded product having a product shape in which the throttle valve 3 is rotatably incorporated in the cylindrical portion 13 is manufactured. In the injection mold according to the present embodiment, the body cavity 57 and the valve cavity 58 are partitioned in a liquid-tight manner (divided into two parts) in the pre-process of the injection molding process, that is, when the injection mold is clamped. ), The insert core 2 is set in advance, and the throttle shaft 4 is set in advance as a reinforcing member for reinforcing the throttle valve 3. The bore inner diameter surface 33 of the insert core 2 is used as a part of an injection mold for molding the outer peripheral side end surface 35 of the resin disk 41 of the throttle valve 3, whereby the outer peripheral side of the resin disk 41 of the throttle valve 3 is used. The end surface shape can be made to follow the bore inner surface shape of the insert core 2.

  As a result, the outer peripheral side end surface shape of the resin disk 41 of the throttle valve 3 is injection molded into a shape following the bore inner diameter surface shape of the insert core 2 without requiring advanced die adjustment technology or advanced die processing technology. Therefore, the accuracy of the clearance dimension between the bore inner diameter surface 33 of the insert core 2 and the outer peripheral side end surface 35 of the resin disk 41 of the throttle valve 3 becomes high, and the amount of leaked air when the throttle valve 3 is fully closed is easily obtained. Moreover, it can be ensured with high accuracy. Further, since the throttle valve 3 can be injection-molded substantially simultaneously with the throttle body 1 in the same injection mold as the throttle body 1 without using the core back method, one injection mold is used. Since the manufacturing time of the resin molded product in is shortened, the cycle time is shortened. As a result, a large amount of resin molded product can be produced per unit time in a single injection mold, so that productivity can be improved.

  Further, the throttle device for an internal combustion engine in which the throttle body 1 and the throttle valve 3 are made of resin and the insert core 2 is insert-molded inside the throttle body 1 can be manufactured without requiring assembly costs. In addition, when the insert core 2 is set in an injection mold and the throttle valve 3 is molded substantially simultaneously with the throttle body 1, the insert core 2 is not deformed by heat or pressure (for example, metal material, ceramics, resin material). Etc.), and before setting the insert core 2 in the injection mold, the inner diameter dimension of the bore inner diameter surface 33 of the insert core 2 is previously cut or polished with high accuracy. If this is the case, the outer peripheral side end surface 35 of the resin disk 41 of the throttle valve 3 is injection molded so as to follow the shape of the bore inner surface of the insert core 2, so that the roundness of the resin disk 41 of the throttle valve 3 can be made highly accurate. Can be secured. Further, even when a resin material such as a thermoplastic resin (for example, PPS, PBT, PA, PP, PEI, or the like) is used as the material of the insert core 2, the melting point is higher than that of the resin material for molding the throttle body 1 and the throttle valve 2. It is desirable to use a resin material having a high value.

  Here, after injection molding of the throttle body 1 and the throttle valve 3, deformation (molding distortion) occurs due to molding shrinkage, and the bore inner surface 33 of the insert core 2 and the outer peripheral side end surface 35 of the resin disk 41 of the throttle valve 3. Even if a gap larger than the design dimension is formed between the bore inner surface 33 of the insert core 2 and the resin disc of the throttle valve 3 by tilting the fully closed position of the throttle valve 3 toward the valve rotation angle 0 °. Since the gap between the outer peripheral side end face 35 of the terminal 41 can be narrowed, the amount of leaked air when the throttle valve 3 is fully closed can be reduced. Further, since the airtight performance when the throttle valve 3 is fully closed can be improved, when the throttle valve 3 is fully closed, between the bore inner diameter surface 33 of the insert core 2 and the outer peripheral side end surface 35 of the resin disk 41 of the throttle valve 3. The gap formed is the size as designed. As a result, the leaked air amount when the throttle valve 3 is fully closed becomes the target air amount, the idle rotation speed substantially matches the target value, and the fuel injection amount is controlled according to the intake air amount. Fuel consumption during driving can be improved.

  The injection mold according to the present embodiment includes a body gate for injecting a molten resin material heated in the body cavity 57, and an injection for injecting a molten resin material heated in the valve cavity 58. The valve gates are provided independently of each other. As a result, the throttle valve 3 can be independently moved with respect to the throttle body 1 without any post-processing after removing the runner in the same injection mold and simultaneously injection molding. In addition, since the insert core 2 is installed at the boundary surface between the body cavity 57 of the injection mold and the valve cavity 58 of the injection mold, the molten state injected from the body gate into the body cavity 57 is provided. Even if the resin material and the molten resin material injected from the valve gate into the valve cavity 58 are the same resin material, the resin material is not attracted, and a defective product such as a molding failure of the throttle body 1 and the throttle valve 3 Therefore, the defective rate of the throttle device for the internal combustion engine in which the throttle body 1 and the throttle valve 3 are both made of resin can be reduced.

  FIG. 3 shows a second embodiment of the present invention and is a view showing the main structure of an injection mold having a burr preventing function.

  The injection mold according to the present embodiment includes first and second movable molds 61 and 62 and first and second movable molds 61 and 62 having shapes corresponding to the cross-sectional shape of the circular space 25 of the insert core 2. On the other hand, it is constituted by a split type slide core 63 that can move freely in the horizontal direction in the figure. The first and second movable molds 61 and 62 have annular outer peripheral grooves 64 and 65 that form an annular gap with the bore inner diameter surface 33 of the insert core 2, and the insert core 2 has a circular space. It is installed so as to be movable in the direction of 25 central axes. The first and second movable molds 61 and 62 are in contact with the bore inner surface 33 of the insert core 2 and are annular first and second sealing members (burr prevention protrusions) 66 that seal the annular gap. , 67 are assembled together. The first and second seal members 66 and 67 are made of a material that is softer than the bore inner diameter surface 33 of the insert core 2.

  With the above configuration, the annular gap formed between the bore inner diameter surface 33 of the insert core 2 and the annular outer peripheral grooves 64 and 65 of the first and second movable molds 61 and 62 is temporarily wide. When the movable mold is moved in the direction of the central axis of the circular space 25, the annular gap is sealed by the first and second seal members 66 and 67, so that the molten resin material becomes the valve cavity of the injection mold. 57 does not enter the annular gap, and no large burr is formed on the outer peripheral side end surface 35 of the resin disk 41 of the throttle valve 3. Further, the annular gap formed between the bore inner diameter surface 33 of the insert core 2 and the annular outer peripheral grooves 64 and 65 of the first and second movable molds 61 and 62 is temporarily narrow, and the insert core 2 has a circular space. When the first and second movable molds 61 and 62 are moved in the direction of the central axis 25, the first and second seal members 66 and 67 are formed of a material softer than the bore inner surface 33 of the insert core 2. Therefore, the first and second seal members 66 and 67 do not scorch and damage the bore inner surface 33 of the insert core 2.

  FIG. 4 shows a third embodiment of the present invention, FIG. 4 (a) shows an example of the insert core bearing structure, and FIG. 4 (b) shows another example of the insert core bearing structure. FIG.

  The throttle valve 3 according to this embodiment includes a throttle shaft 4 having a rotation center axis in a direction substantially perpendicular to the center axis direction of the throttle bore 14 of the cylindrical portion 13 of the throttle body 1 and the circular space 25 of the insert core 2. It is assembled integrally. Then, both ends of the throttle shaft 4 in the rotation center axial direction (axial direction) are installed so as to protrude from the outer peripheral side end face 35 of the resin disk 41 of the throttle valve 3 toward the insert core 2 side. The insert core 2 is integrally formed with first and second valve bearing portions 26 and 27 that rotatably support both end portions (first and second bearing sliding portions) of the throttle shaft 4 in the axial direction. Has been.

  Then, in the first and second valve bearing portions 26 and 27, the first and second shafts having a round hole shape through which both end portions (first and second bearing sliding portions) in the axial direction of the throttle shaft 4 pass. Through holes 31 and 32 are provided. Then, both end portions (first and second bearing sliding portions) in the axial direction of the throttle shaft 4 are slidable in the rotational direction on the inner circumferences of the first and second shaft through holes 31 and 32 of the insert core 2. A bearing member 9 having first and second sliding holes 71 and 72 that are pivotally supported by the shaft is press-fitted and fitted. The bearing member 9 is a slide bearing, a thrust bearing, or a bearing bush integrally formed in a predetermined substantially cylindrical shape by a sintered bearing material having excellent wear resistance.

  Here, as shown in FIG. 4A, the throttle body 1 and the throttle valve 3 are injection-molded, and then the bearing member 9 is inserted into the first and second shaft through holes 31 and 32 of the insert core 2. You may press-fit. Further, as shown in FIG. 4B, before the insert core 2 is set in the injection mold, the bearing member 9 is placed in the first and second shaft through holes 31 and 32 of the insert core 2 in advance. The bearing member 9 may be insert-molded simultaneously with the insert core 2 in the cylindrical portion 13 of the throttle body 1 by press-fitting. Thus, the center axis of the first and second shaft through holes 31 and 32 of the insert core 2 or the center axis of the first and second sliding holes 71 and 72 of the bearing member 9 and the rotation center axis of the throttle shaft 4 are arranged. The coaxiality can be ensured with high accuracy.

  FIG. 5 shows Embodiment 4 of the present invention, FIG. 5 (a) is a view showing a bearing structure of an insert core, and FIG. 5 (b) is a view showing an insert core.

  The insert core 2 of the present embodiment is formed of a sintered bearing material having excellent wear resistance. The first and second shaft through-holes 31 and 32 of the insert core 2 are slides that axially support both end portions (first and second bearing sliding portions) of the throttle shaft 4 so as to be slidable in the rotational direction. It functions as a moving hole. Thereby, it is not necessary to press-fit the bearing member 9 to the inner periphery of the first and second shaft through holes 31 and 32 of the insert core 2, and the assembling cost can be reduced.

  Further, the coaxiality between the center axis of the first and second shaft through holes 31 and 32 of the insert core 2 and the rotation center axis of the throttle shaft 4 can be ensured with high accuracy. Then, the outer wall surfaces of the first and second valve bearing portions 26 and 27 of the insert core 2 of the present embodiment are projected to both end sides (outside sides) in the axial direction from the outer wall surface 34 of the insert core 2. Is formed. Further, the outer wall surfaces of the first and second valve bearing portions 26 and 27 of the insert core 2 are formed so as to protrude toward both ends (outside sides) in the axial direction from the outer peripheral surface of the cylindrical portion 13 of the throttle body 1. Has been. The outer wall surfaces of the first and second valve bearing portions 26 and 27 may be provided so as to be flush with the outer wall surface 34 of the insert core 2.

[Modification]
In this embodiment, the rotational power of the drive motor (actuator) is transmitted to the throttle shaft (in this example, the throttle shaft 4) via a power transmission mechanism such as a gear reduction mechanism, and the rotational angle of the throttle valve 3 is determined. Although the example applied to the throttle device for an internal combustion engine (electronically controlled throttle control device) that controls (valve opening, valve opening, throttle opening) according to the accelerator operation amount of the driver has been described, the present invention, You may employ | adopt for the throttle apparatus for internal combustion engines which does not have power units, such as a drive motor. In this case, instead of the valve gear 6 provided integrally with the other end (or one end) of the throttle shaft 4, an accelerator lever mechanically connected to the accelerator pedal or the throttle lever via a wire cable is provided. . Even in this case, the driver's accelerator operation amount can be transmitted to the throttle valve 3 and the throttle shaft 4.

  In this embodiment, the throttle valve 3 is integrally formed of a resin material and the throttle shaft 4 is integrally formed of a metal material. However, both the throttle valve 3 and the throttle shaft 4 are formed of a resin material. You may form integrally. Further, a resin shaft portion (cylindrical portion) is formed on the outer periphery of the valve holding portion of the throttle shaft 4, and the resin shaft portion (resin shaft 42) of the throttle valve 3 and the resin shaft portion of the throttle shaft 4 are heated. You may make it couple | bond by welding. Further, either one or both of the fully closed stopper portion and the fully opened stopper portion may be provided directly on the throttle valve 3 or the throttle shaft 4. In this case, either or both of a fully closed stopper and a fully opened stopper are provided on the bore inner diameter side of the insert core 2.

  Further, the inner peripheral surfaces of the first and second shaft through holes 21 and 22 of the first and second valve bearing portions 15 and 16 of the cylindrical portion 13 of the throttle body 1 or the first and second shaft through holes of the insert core 2. A lubricant having excellent lubricity, such as a fluorine-based resin, may be applied between the inner peripheral surfaces of 31 and 32 and the outer peripheral surfaces of both end portions in the axial direction of the throttle shaft 4. Further, a release agent or a lubricant (for example, fluorine-based resin, molybdenum disulfide, etc.) may be applied to the outer peripheral surfaces of both end portions of the throttle shaft 4 in the axial direction. Thereby, the control responsiveness of the throttle valve 3 and the throttle shaft 4 can be further improved.

Further, as a resin material for molding the throttle body 1 and the throttle valve 3, a heated resin material (for example, a molten resin made of a thermoplastic resin) and a filler (for example, high-strength, low-cost glass fiber or powder) are used. Jo metal (aluminum), or fiber-like metal or powdered carbon or carbon fibers or high mineral dimensional accuracy, (calcium carbide: CaCO _3, etc.)) or additive mixing or the added resin (For example, polybutylene terephthalate containing 30% glass fiber: PBTG30 or polyphenylene sulfide containing 50% glass fiber: PPSG50) may be used.

  In addition, the biting property (coupling performance) between the inner circumference of the resin shaft 42 of the throttle valve 3 and the outer circumference of the valve holding portion of the throttle shaft 4 is improved, and the axial relative of the throttle valve 3 to the throttle shaft 4 is improved. In order to prevent movement, that is, in order to prevent the throttle valve 3 from coming off from the valve holding portion of the throttle shaft 4, a part or all of the outer peripheral surface of the valve holding portion of the throttle shaft 4 is knurled. Also good. For example, a notch or an uneven portion may be formed on a part or all of the outer peripheral surface of the valve holding portion of the throttle shaft 4. Alternatively, the cross-sectional shape of the valve holding portion of the throttle shaft 4 may be a substantially circular shape having a two-sided width, and the cross-sectional shape of the resin shaft 42 of the throttle valve 3 may be a substantially cylindrical shape having a two-sided width. Thereby, the relative rotational movement of the throttle valve 3 and the throttle shaft 4 in the rotational direction can be prevented.

It is sectional drawing which showed schematic structure of the injection mold (Example 1). (A) is sectional drawing which showed the main structures of the throttle apparatus for internal combustion engines, (b) is the perspective view which showed the insert core (Example 1). (Example 2) which is sectional drawing which showed the main structures of the injection mold which has a burr | flash prevention function. (A) is the exploded view which showed an example of the bearing structure of an insert core, (b) is sectional drawing which showed the other example of the bearing structure of an insert core (Example 3). (A) is sectional drawing which showed the bearing structure of the insert core, (b) is the perspective view which showed the insert core (Example 4).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Throttle body 2 Insert core 3 Throttle valve 4 Throttle shaft 9 Bearing member 13 Cylindrical part of throttle body 14 Throttle bore of throttle body 25 Circular space of insert core 31 First shaft through hole (sliding hole) of insert core
32 Insert shaft second shaft through hole (sliding hole)
33 Bore inner diameter surface of insert core 35 Outer peripheral end surface of throttle valve 51 Fixed mold (injection mold)
52 Movable mold (injection mold)
57 Body cavity in injection mold 58 Valve cavity in injection mold 61 First movable mold (movable mold)
62 Second movable mold (movable mold)
64 Annular outer peripheral groove (outer peripheral part) of the first movable mold
65 Annular outer peripheral groove (outer peripheral part) of the second movable mold
66 First seal member of first movable mold (burr prevention protrusion)
67 Second seal member of second movable mold (burr prevention protrusion)
71 First sliding hole of bearing member 72 Second sliding hole of bearing member

Claims (7)

The throttle body formed with a throttle bore communicating with the cylinder of the internal combustion engine and the throttle valve for adjusting the amount of intake air flowing through the throttle bore are made of resin, and a part of the throttle bore is formed inside the throttle body A throttle device for an internal combustion engine in which an insert core having a circular space is insert-molded,
In the method of manufacturing a throttle device for an internal combustion engine, wherein the throttle body and the throttle valve are molded substantially simultaneously in the same molding die.
(A) The insert core is set in the molding die, and the cavity formed in the molding die is made into a body cavity having a shape corresponding to the product shape of the throttle body and the product shape of the throttle valve. A first step of dividing into at least two correspondingly shaped valve cavities;
(B) Injecting molten resin material into the body cavity and the valve cavity using the bore inner diameter surface of the insert core as a part of the molding die forming the outer peripheral side end surface of the throttle valve And a second step of filling, and a method of manufacturing a throttle device for an internal combustion engine. In the manufacturing method of the throttle device for internal-combustion engines according to claim 1,
The molding die is provided independently of the first resin injection port for injecting the molten resin material into the body cavity and the first resin injection port. And a second resin injection port for injecting the resin material in a state. In the manufacturing method of the throttle device for internal-combustion engines according to claim 1 or 2,
The molding die has a movable mold having a shape corresponding to the cross-sectional shape of the circular space,
The movable mold has an outer peripheral portion that forms an annular gap with the bore inner surface of the insert core, and is installed in the insert core so as to be movable in the direction of the central axis of the circular space.
The movable mold is integrally assembled with a seal member that contacts the bore inner surface of the insert core and seals the annular gap.
The method for manufacturing a throttle device for an internal combustion engine, wherein the seal member is made of a material softer than a bore inner diameter surface of the insert core. In the manufacturing method of the throttle device for internal-combustion engines according to any one of claims 1 to 3,
The method of manufacturing a throttle device for an internal combustion engine, wherein the insert core is formed of a material that does not deform when the throttle valve is molded substantially simultaneously with the throttle body. In the manufacturing method of the throttle device for internal-combustion engines according to any one of claims 1 to 4,
The throttle valve is integrally assembled with a throttle shaft having a rotation center axis in a direction substantially orthogonal to the center axis direction of the throttle bore,
One end portion or both end portions of the throttle shaft in the rotation center axis direction are installed so as to protrude from the outer peripheral side end surface of the throttle valve to the insert core side,
A method of manufacturing a throttle device for an internal combustion engine, wherein the insert core is provided with a through-hole through which one or both ends of the throttle shaft pass. In the manufacturing method of the throttle device for internal-combustion engines according to claim 5,
A bearing member having a sliding hole that slidably supports one end portion or both end portions of the throttle shaft in the rotation direction is press-fitted and fitted to the inner periphery of the through hole of the insert core. A method of manufacturing a throttle device for an internal combustion engine. In the manufacturing method of the throttle device for internal-combustion engines according to claim 5,
The insert core is formed of a bearing material having excellent wear resistance,
Manufacturing of a throttle device for an internal combustion engine, wherein the through hole constitutes a sliding hole that pivotally supports one end portion or both end portions of the throttle shaft in the rotational center axis direction so as to be slidable in the rotational direction. Method.

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