JP2006009683A - Intake air throttling device for internal combustion engines - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To eliminate the need for an excessive pressure contact force and prevent unnecessary deformation from being exerted on a bore inside diameter face 10 of a throttle body 7. <P>SOLUTION: A basis part 51, minute protrusion parts 52, and minute groove parts 53 are integrally formed in a bore inside diameter surface 10 of a resinified throttle body 7 such that a number of unevenness is alternately repeated. This constitution rotates a throttle valve 5 in a manner to close in a totally enclosed direction and can decrease an area of contact between an outer peripheral end face part 34 of a throttle valve and a bore inside diameter surface 10 of the throttle body 7 when the outer peripheral end face part 34 of the throttle valve 5 is brought into pressure contact with the bore inside diameter surface 10 of the throttle body 7. Therefore, the bore inside diameter surface of the resinified throttle body 7 can be thermally deformed easily, an excessive contact pressure is not needed, and an unnecessary deformation can be prevented from being exerted on the bore inside diameter surface 10 of the throttle body 7. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an intake throttle device for an internal combustion engine that controls an engine torque or an engine speed by changing an intake air amount sucked into a combustion chamber of the internal combustion engine corresponding to a driver's accelerator operation amount or throttle operation amount. In particular, the present invention relates to an intake throttle device for an internal combustion engine in which the amount of leaked air is reduced when the throttle valve is fully closed.

[Conventional technology]
In recent years, as a circumstance surrounding an internal combustion engine, demands for reducing fuel consumption are increasing due to legal regulations and the like. One technique for meeting this requirement is to reduce the amount of leaked air when the throttle valve that controls the amount of intake air taken into the combustion chamber of the internal combustion engine is fully closed. Here, as shown in FIG. 6, a tubular throttle body 102 forming a throttle bore 101 having a circular cross section, and both end portions in the axial direction of the valve holding portion are rotatably supported by the throttle body 102. An intake throttle device for an internal combustion engine is proposed that includes a throttle shaft 104 and a disc-shaped throttle valve 105 that is integrally attached to the throttle shaft 104 and corresponds to the cross-sectional shape of the throttle bore 101 ( For example, see Patent Document 1).

  This is because the throttle body 102 is made of resin for the purpose of weight reduction and cost reduction. Then, as shown in FIG. 6 (a), the throttle valve 105 is pressed in the fully closed direction and vibrated by the vibration cone 106 which is a vibrating body, and the throttle bore wall surface (bore inner diameter surface) 103 of the throttle body 102 and This contact portion is heated by repeatedly separating the contact portion with the outer peripheral end surface portion of the throttle valve 105. That is, the resin material of the contact portion is melted and deformed by heating on the principle of vibration welding. In the technique described in Patent Document 1, both the throttle body 102 and the throttle valve 105 are made of resin, but the throttle valve 105 uses a resin material having a lower melting point than the throttle body 102.

  As a result, the outer peripheral end surface portion of the throttle valve 105 is pressed against the bore inner diameter surface 103 of the throttle body 102 while being heated and thermally deformed, so that the throttle valve 105 is fully closed as shown in FIG. The time posture can be set to a rotation angle that is more perpendicular to the axis of the throttle bore 101 (in the fully closed direction). As a result, the gap between the bore inner diameter surface 103 and the outer peripheral end surface of the throttle valve 105 when the throttle valve 105 is fully closed can be reduced, and the amount of leakage air when the throttle valve 105 is fully closed can be reduced. It becomes possible.

[Conventional technical problems]
However, in the inner diameter shape of the bore inner diameter surface 103 and the outer diameter shape of the outer peripheral end surface portion of the throttle valve 105 described in Patent Document 1, in order to reduce the clearance around the throttle valve 105, the bore inner diameter surface 103 or the throttle valve 105 The outer peripheral end face portion needs to be largely thermally deformed, an excessive pressure contact force is required, and unnecessary thermal deformation may be applied to the bore inner diameter face or the outer peripheral end face portion of the throttle valve 105.
JP 2001-248463 A (page 1-4, FIG. 1 to FIG. 3)

  An object of the present invention is to provide a convex or concave contact portion on either the throttle bore wall surface of the resinized throttle body or the outer peripheral end surface portion of the throttle valve, thereby eliminating the need for excessive pressure contact force. An object of the present invention is to provide an intake throttle device for an internal combustion engine that can prevent unnecessary deformation of a wall surface or an outer peripheral end surface portion of a throttle valve.

  According to the first aspect of the present invention, either the throttle bore wall surface of the throttle body or the outer peripheral end surface portion of the throttle valve that directly contacts the throttle bore wall surface is made of resin for the purpose of weight reduction and cost reduction. (For example, resin integral molding using a resin material such as a thermoplastic resin). When the throttle bore wall surface and the outer peripheral end surface portion of the throttle valve are brought into direct contact with either the resinized throttle bore wall surface or the outer peripheral end surface portion of the throttle valve, the throttle bore wall surface and the outer peripheral end surface of the throttle valve A convex or concave contact portion is provided for reducing the contact area with the portion.

  This reduces the contact area between the throttle bore wall surface and the outer peripheral end surface portion of the throttle valve when the throttle bore wall surface and the outer peripheral end surface portion of the throttle valve are in direct contact with each other. Alternatively, either one of the outer peripheral end surfaces of the throttle valve can be easily deformed, and an excessive pressure contact force is not required, thereby preventing unnecessary deformation of the throttle bore wall surface or the outer peripheral end surface of the throttle valve. Can do. In addition, when the throttle valve is set to a rotation angle corresponding to the fully closed position, the gap between the throttle bore wall surface of the throttle body and the outer peripheral end surface of the throttle valve becomes the minimum necessary clearance, and the throttle valve Since the amount of leaked air at the time of closing can be reduced, the demand for reduction in fuel consumption can be satisfied. Here, a gap remains between the throttle bore wall surface of the throttle body and the outer peripheral end surface portion of the throttle valve in the portion that could not be deformed, but the air passage formed by the gap has a labyrinth shape. The amount of intake air passing through the actual gap can be suppressed.

  According to the second aspect of the present invention, by providing a minute protrusion or minute groove as the convex or concave contact portion, the throttle bore wall surface and the outer peripheral end surface portion of the throttle valve are brought into direct contact with each other. When the shape of either the throttle bore wall surface or the outer peripheral end surface portion of the throttle valve is deformed to follow the shape of either the throttle bore wall surface or the outer peripheral end surface portion of the throttle valve, the throttle bore wall surface and the throttle valve The contact area with the outer peripheral end face can be reduced. Either the throttle bore wall surface of the throttle body or the outer peripheral end surface portion of the throttle valve that directly contacts the throttle bore wall surface is made of resin (for example, resin integral molding with a resin material such as thermoplastic resin), and the throttle bore Provided on either the throttle bore wall surface or the outer peripheral end surface portion of the throttle valve by laser heating either the throttle bore wall surface or the outer peripheral end surface portion of the throttle valve while pressing the wall surface and the outer peripheral end surface portion of the throttle valve. Alternatively, the tip (or the tip) of the minute protrusion may be thermally deformed.

  According to the third aspect of the present invention, the minute protrusions or the minute grooves may be provided in a sawtooth shape so that irregularities are alternately repeated on the wall surface of the throttle bore. The minute protrusion may be a minute streak protruding from the reference surface having a predetermined radius of curvature centering on the central axis of the throttle bore inward in the radial direction. Further, the minute groove portion may be a minute streak-like recess that is recessed outward in the radial direction from the reference surface having a predetermined radius of curvature centered on the central axis of the throttle bore. Here, a coating agent (such as molybdenum disulfide) for filling the gap between the throttle bore wall surface of the throttle body and the outer peripheral end surface portion of the throttle valve, or the throttle bore wall surface of the throttle body and the outer peripheral end surface portion of the throttle valve. A coating agent (fluorine-based resin or the like) that reduces the sliding resistance may be applied or coated on the throttle bore wall surface. In this case, since the contact surface between the coating agent and the throttle bore wall surface increases, the adhesion between the coating agent and the throttle bore wall surface is improved, and the coating agent is difficult to peel off from the throttle bore wall surface.

  According to the fourth aspect of the present invention, minute projections or minute groove portions may be provided in a sawtooth shape so that irregularities are alternately repeated on the outer peripheral end surface portion of the throttle valve. The minute protrusions may be minute streak-like protrusions protruding outward in the radial direction from the reference surface having a predetermined radius of curvature centering on the rotation center axis of the shaft. Further, the minute groove portion may be a minute streak-like recess that is recessed inward in the radial direction from a reference surface having a predetermined radius of curvature centering on the rotation center axis of the shaft. Here, a coating agent (such as molybdenum disulfide) for filling the gap between the throttle bore wall surface of the throttle body and the outer peripheral end surface portion of the throttle valve, or the throttle bore wall surface of the throttle body and the outer peripheral end surface portion of the throttle valve. A coating agent (fluorine resin or the like) that reduces the sliding resistance between the two may be applied to or coated on the outer peripheral end surface of the throttle valve. In this case, since the contact surface between the coating agent and the outer peripheral end surface portion of the throttle valve increases, the adhesion between the coating agent and the outer peripheral end surface portion of the throttle valve is improved, and the coating agent is applied from the outer peripheral end surface portion of the throttle valve. It becomes difficult to peel off.

  According to the fifth aspect of the present invention, the shape of either the resin-made throttle bore wall surface or the outer peripheral end surface portion of the throttle valve is changed to the other shape of the throttle bore wall surface or the outer peripheral end surface portion of the throttle valve. You may provide the micro projection part which has a curvature radius so that it may contact with the outer peripheral end surface part or throttle-bore wall surface of a throttle valve in the state before making it deform | transform so that it may copy. In addition, in a state before the resin-made throttle bore wall surface or the outer peripheral end surface portion of the throttle valve is deformed so as to follow the shape of either the throttle bore wall surface or the outer peripheral end surface portion of the throttle valve. Further, a minute groove portion having a radius of curvature that does not directly contact the outer peripheral end surface portion or the throttle bore wall surface of the throttle valve may be provided.

  According to the sixth aspect of the present invention, when the rotary drive body directly or indirectly contacts the locking portion of the throttle body, the rotation operation of the throttle valve in the fully closed direction is restricted at the fully closed position. . When the throttle valve is fully closed, the rotation angle of the throttle valve is indefinitely perpendicular to the axial direction of the throttle bore within the range where the outer peripheral end face of the throttle valve and the throttle bore wall surface do not directly contact each other. The rotation angle is set so as to approach. At this time, as described above, the shape of either the resin-made throttle bore wall surface or the outer peripheral end surface portion of the throttle valve follows the shape of the other one of the throttle bore wall surface or the outer peripheral end surface portion of the throttle valve. Since it is deformed, even if the rotation angle of the throttle valve is made closer to the axis of the throttle bore than the current fully closed position, the throttle valve's outer peripheral surface and the throttle bore wall surface are prevented from galling. In addition, the gap between the outer peripheral end face of the throttle valve and the throttle bore wall surface can be reduced to the minimum required minimum gap. Therefore, the amount of leaked air when the throttle valve is fully closed can be further reduced as compared with the current one.

  According to the seventh aspect of the present invention, when the rotary drive body directly or indirectly contacts the locking portion of the throttle body, the rotation operation of the throttle valve in the fully closed direction is restricted at the fully closed position. . Even when the throttle valve is fully closed, the rotation angle of the throttle valve is set to a rotation angle capable of forming a minute gap between the outer peripheral end surface portion of the throttle valve and the throttle bore wall surface. Therefore, the amount of leaked air when the throttle valve is fully closed becomes a predetermined amount of leaked air that is further reduced as compared with the current one.

  The best mode for carrying out the present invention is to eliminate the need for excessive pressure contact force and to prevent unnecessary deformation of the throttle bore wall surface or the outer peripheral end surface of the throttle valve. When the throttle bore wall surface and the outer peripheral end surface portion of the throttle valve are brought into direct contact with either the throttle bore wall surface or the outer peripheral end surface portion of the throttle valve, the contact area between the throttle bore wall surface and the outer peripheral end surface portion of the throttle valve This is realized by providing a convex or concave contact portion for reducing the above.

[Configuration of Example 1]
FIGS. 1 to 5 show Embodiment 1 of the present invention, and FIGS. 1 and 2 are views showing the overall configuration of an intake throttle device for an internal combustion engine.

  The intake throttle device for an internal combustion engine according to the present embodiment is based on an intake system of an internal combustion engine (for example, an engine for a two-wheeled vehicle: hereinafter referred to as an engine) based on a driver's throttle operation amount, that is, an internal portion of an intake port and a cylinder Incorporated in the middle of the intake pipe through which intake air flows into the combustion chamber), and is sucked into the cylinder of the engine based on the throttle operation amount of a throttle operation part such as a throttle lever or throttle handle of a vehicle such as a two-wheeled vehicle. It is a device that controls the engine speed or the engine torque by changing the amount of intake air that is generated. Note that the throttle operation amount corresponds to a driver's accelerator pedal depression amount (accelerator operation amount) in a four-wheeled vehicle. Here, the engine obtains an output (for example, engine output shaft torque) by heat energy obtained by burning a mixture of intake air and fuel in a combustion chamber.

  This intake throttle device for an internal combustion engine includes an idle opening adjusting bolt 2 assembled to an accelerator bracket 1 and an accelerator lever 3 mechanically connected to a throttle operating part such as a throttle lever or a throttle handle via a wire cable. A throttle shaft 4 integrated with the accelerator lever 3, a butterfly valve type throttle valve 5 rotating integrally with the throttle shaft 4, and the throttle valve 5 are fully closed so that the amount of intake air is minimized. An intake throttle valve device for an internal combustion engine including a return spring (valve urging means, elastic body) 6 for urging in a direction to return to a position and a throttle body 7 forming an intake pipe of the engine. Here, the return spring 6 is mounted on the outer peripheral side of the throttle shaft 4 and between the back surface of the accelerator lever 3 and the outer wall surface of the throttle body 7.

  In the intake throttle device for an internal combustion engine of this embodiment, as shown in FIGS. 1 and 2, the accelerator lever 3, the throttle shaft 4, the throttle valve 5 and the throttle body 7 are made of resin for the purpose of reducing the weight and cost. It has become. In particular, the non-cylindrical shaft side fitting portion (cylindrical portion) 11 of the throttle shaft 4 and the non-cylindrical valve side fitting portion (cylindrical portion) 12 of the throttle valve 5 are made of resin, A fitting portion between the shaft side fitting portion 11 and the valve side fitting portion 12 of the throttle valve 5 is fixed by using, for example, heat welding such as laser welding. The intake pipe of the engine has an intake duct (not shown) hermetically coupled to the downstream end of the case of an air cleaner (filter element: not shown) for filtering the intake air, and is airtight at the downstream end of the intake duct. The throttle body 7 is connected to the throttle body 7 and the intake pipe (not shown) is airtightly connected to the downstream end of the throttle body 7.

  The accelerator bracket 1 is integrally formed in a predetermined shape, for example, by press forming a metal plate such as a cold rolled steel plate (SPCC), and moves in the reciprocating direction on the valve opening side and valve closing side wire cables. It has two claw-like parts 13 for holding freely. The accelerator bracket 1 includes a plate-like full-close stopper 15 that indirectly contacts the full-close stopper portion 14 of the accelerator lever 3 when the throttle valve 5 is fully closed, and the accelerator lever 3 when the throttle valve 5 is fully opened. A flat open stopper (not shown) with which the fully open stopper portion (not shown) directly or indirectly abuts is integrally provided.

  Here, in this embodiment, an idle opening adjustment mechanism that manually adjusts the accelerator bracket 1 so that the rotation angle (valve opening, idle opening) of the throttle valve 5 during idle operation falls within an appropriate range. Is provided. The idle opening adjusting mechanism is held by the full-close stopper 15 and the full-close stopper 15 and is directly held by the full-close stopper portion 14 of the accelerator lever 3 when the throttle valve 5 is fully closed. It comprises an idle opening adjusting bolt (idle opening adjusting screw) 2 and the like that come into contact with each other. Here, the fully closed stopper 15 of the accelerator bracket 1 of the present embodiment has a plate thickness direction (vertical direction in the drawing) so that the upper end surface in the drawing and the lower end surface in the drawing are communicated in FIGS. A screw hole (female screw hole: not shown) is formed.

  The idle opening adjusting bolt 2 is a so-called through bolt, and a bolt head 16 positioned on the opposite side of the fully closed stopper portion 14 side with respect to the upper end surface of the fully closed stopper 15 in the figure, and the bolt head. A bolt shaft portion (shaft-like portion) that is tightened into the screw hole of the fully closed stopper 15 with the outer diameter smaller than 16 and the tip side protruding from the lower end surface of the fully closed stopper 15 to the fully closed stopper portion 14 side. )have. A cylindrical portion (column portion) having a larger outer diameter than the screw hole of the fully closed stopper 15 is formed near the bolt head portion 16 of the bolt shaft portion, and on the outer periphery on the tip side of the bolt shaft portion. A male screw portion 17 that can be screwed into the screw hole of the fully closed stopper 15 is formed. A coil-shaped compression spring 8 is mounted on the outer periphery of the cylindrical portion of the bolt shaft portion located between the upper end surface of the fully closed stopper 15 and the lower end surface of the bolt head 16. The compression spring 8 prevents the idle opening of the throttle valve 5 from changing by urging the idle opening adjusting bolt 2 toward the bolt head 16.

  The accelerator lever 3 is integrally formed by resin molding on the outer periphery of one end of the throttle shaft 4 in the rotation center axial direction (axial direction). A substantially V-shaped wire cable (not shown) wound around a throttle lever such as a throttle lever or a throttle handle operated by the driver is wound around the outer periphery of the accelerator lever 3. A circumferential groove portion 21 is provided. Further, on the outer peripheral portion of the accelerator lever 3, valve opening side and valve closing side mounting grooves 22 for attaching one end portions of the valve opening side and valve closing side wire cables are provided. A boss-shaped thick portion 23 is provided on the back surface of the accelerator lever 3. The thick portion 23 is provided so as to protrude from the periphery toward the outer wall surface of the throttle body 7. The thick portion 23 has a block-like (or convex) full-close that directly contacts the lower end (tip) of the bolt shaft portion of the idle opening adjusting bolt 2 when the throttle valve 5 is fully closed. The stopper part (contact part) 14 and the block-shaped (or convex) full-open stopper part (contact part) that directly or indirectly contact the full-open stopper of the accelerator bracket 1 when the throttle valve 5 is fully opened are made of resin. It is integrally formed by molding.

  The throttle shaft 4 is made of, for example, a resin material such as a thermoplastic resin (heat-resistant resin: for example, polybutylene terephthalate: PBT, or polyphenylene sulfide: PPS, or polyamide resin: PA, or polypropylene: PP, or polyetherimide: PEI). Insert-molding a split-type metal member made of a metal material (for example, stainless steel such as SUS304) for reinforcing the resin molding part such as the shaft side fitting part 11 into the shaft side fitting part 11 integrally molded by resin This is a valve shaft (rotating shaft). The shaft side fitting portion 11 is a non-cylindrical valve fixing portion (valve holding portion, resin shaft) that fixes the valve side fitting portion 12 of the throttle valve 5 using a heat welding method such as laser welding. The valve fixing portion refers to a portion of the valve side fitting portion 12 of the throttle valve 5 that is located in the throttle bore 9 of the throttle body 7. On the outer peripheral surface of the shaft-side fitting portion 11, two flat surfaces (two-surface width portions) are formed for increasing the welding strength at the time of laser welding. The outer peripheral surface of the shaft-side fitting portion 11 excluding the two flat surfaces is an arc-shaped curvature surface centered on the rotation center axis of the throttle shaft 4. In addition, after fitting the valve side fitting part 12 of the throttle valve 5 on the outer periphery of the shaft side fitting part 11 of the throttle shaft 4, the valve side fitting of the throttle valve 5 to the shaft side fitting part 11 of the throttle shaft 4 is performed. The joint portion 12 may be fastened and fixed using a screw such as a fixing bolt or a fastening screw.

  As shown in FIG. 2, the split-type metal member includes a central shaft-like metal shaft 31 disposed in the entire axial direction from one end surface to the other end surface of the throttle shaft 4, and a portion on the outer periphery of the metal shaft 31. In particular, the metal pipe 32 is fitted with a cylindrical gap and disposed on the same axis as the metal shaft 31. The metal shaft 31 of the throttle shaft 4 is insert-molded inside the shaft-side fitting portion 11, and a portion that fits with the shaft-side fitting portion 11 is a small-diameter portion having a cylindrical shape. In the metal shaft 31, the surface portion of the other end portion in the axial direction from the shaft side fitting portion 11 is exposed on the outer peripheral surface of the throttle shaft 4, and the exposed portion is the second shaft sliding hole of the throttle body 7. A second bearing sliding portion (cylindrical large diameter portion) that is rotatably supported on the inner peripheral surface is configured. The valve side fitting portion 12 of the throttle valve 5 is fitted on the outer periphery of the valve holding portion of the metal shaft 31 via the shaft side fitting portion 11.

  The metal pipe 32 of the throttle shaft 4 is fitted to the outer periphery of one axial end portion of the shaft side fitting portion 11, and the fitting portion is exposed on the outer circumferential surface of the throttle shaft 4, and the exposed portion is the throttle. A first bearing sliding portion is rotatably supported on the inner peripheral surface of the first shaft sliding hole of the body 7. The accelerator lever 3 is integrally formed of the same resin material as that of the shaft-side fitting portion 11 at one end portion of the throttle shaft 4 in the rotation center axis direction (axial direction). Here, in this embodiment, a heated and molten resin material (for example, a molten resin made of a thermoplastic resin) is injected from a lever gate into a lever cavity of a resin molding die and then cooled and solidified ( The resin accelerator lever is manufactured by injection molding of a resin material. At this time, the shaft side fitting portion 11 of the throttle shaft 4 is also resin-molded, and the metal shaft 31 and the metal pipe 32 are insert-molded inside the shaft side fitting portion 11 and the accelerator lever 3.

  The throttle valve 5 is, for example, a resin material such as a thermoplastic resin (heat-resistant resin: for example, polybutylene terephthalate: PBT, or polyphenylene sulfide: PPS, or polyamide resin: PA, or polypropylene: PP, or polyetherimide: PEI). The resin molded product integrally formed by the above-described method is accommodated in the throttle bore 9 of the throttle body 7 so as to be freely opened and closed. Here, in this embodiment, a heated and molten resin material (for example, a molten resin made of a thermoplastic resin) is injected from a valve gate into a valve cavity of a resin molding die, and then cooled and solidified ( The resin throttle valve is manufactured by injection molding of a resin material.

  This throttle valve 5 is a butterfly valve type having a rotation center axis in a direction substantially orthogonal to the throttle bore 9 of the throttle body 7, that is, the center axis direction of the intake passage (the axis direction of the average flow of intake air). The rotation angle (valve angle, valve opening) is changed within the range of rotational operation from the fully closed position that minimizes the intake air amount to the fully open position that maximizes the intake air amount. Thus, the amount of intake air taken into the cylinder of the engine is controlled. The throttle valve 5 of the present embodiment has a valve angle changed according to the throttle operation amount of a throttle operation part such as a throttle lever or a throttle handle of a vehicle such as a two-wheeled vehicle for adjusting the amount of intake air into the combustion chamber of the engine. Is done.

  As shown in FIGS. 2 to 5, the throttle valve 5 includes a non-cylindrical valve-side fitting portion 12 that is fitted and held on the outer periphery of the shaft-side fitting portion 11 of the throttle shaft 4, and A disc-shaped portion (valve body) that is connected to the valve-side fitting portion 12 and is radially expanded around the intersection of the center axis of the throttle bore 9 of the throttle body 7 and the rotation center axis of the throttle shaft 4. ) 33 is formed integrally. The valve side fitting portion 12 of the throttle valve 5 is fixed by using a heat welding method such as laser welding after being fitted to the outer periphery of the shaft side fitting portion 11 of the throttle shaft 4. This valve-side fitting portion 12 is press-fitted and fixed to the outer periphery of the shaft-side fitting portion 11 of the throttle shaft 4 at the center portion or at least one end portion of the fitting portion of the throttle shaft 4 with the shaft-side fitting portion 11 ( It has a throttle part (press-fit part) to be fitted.

  An oblong through hole (fitting hole) that penetrates in the axial direction is formed in the valve side fitting portion 12. Further, in the inner peripheral surface of the valve side fitting portion 12, the portion corresponding to the two flat surfaces (two surface width portions) formed on the outer peripheral surface of the shaft side fitting portion 11 of the throttle shaft 4, Two flat surfaces (two-surface width portions) are formed. This functions as a relative motion restricting means for preventing relative rotational motion between the shaft side fitting portion 11 of the throttle shaft 4 and the valve side fitting portion 12 of the throttle valve 5. The inner peripheral surface and the outer peripheral surface of the valve-side fitting portion 12 excluding two flat surfaces (two-surface width portions) are arc-shaped around the rotation center axis of the shaft-side fitting portion 11 of the throttle shaft 4. It is considered as a curvature surface.

  The disc-shaped portion 33 of the throttle valve 5 is formed integrally with the outer peripheral portion of the valve side fitting portion 12. When the rotation angle of the throttle valve 5 is set to the rotation angle corresponding to the valve fully closed position, that is, when the throttle valve 5 is fully closed, An annular outer peripheral end face portion 34 that is substantially parallel to the axial direction is provided. Further, one end face or both end faces of the semi-disc-like portion of the disc-like portion 33 of the throttle valve 5 are arranged on the outer peripheral portion of the valve-side fitting portion 12 and the vicinity of the outer peripheral end-face portion 34 of the disc-like portion 33. A plurality of reinforcing ribs 35 are integrally formed substantially radially so as to connect the two.

  The throttle body 7 is made of, for example, a resin material such as a thermoplastic resin (heat-resistant resin: for example, polybutylene terephthalate: PBT, or polyphenylene sulfide: PPS, or polyamide resin: PA, or polypropylene: PP, or polyetherimide: PEI). This is a resin molded product that is integrally molded (resinized) by the above, and is a device (housing) that accommodates and holds the throttle shaft 4 and the throttle valve 5 so as to be freely opened and closed. Here, in the present embodiment, a heated resin material (for example, a molten resin made of a thermoplastic resin) is injected from the body gate into the body cavity of the resin molding die and then cooled and solidified ( The resin throttle body is manufactured by injection molding of a resin material.

  Here, the throttle body 7 is provided with a cylindrical throttle bore portion (cylindrical wall, bore wall portion) that forms a throttle bore 9 having a substantially circular cross section. As shown in FIGS. 2 to 5, the throttle bore 9 is an intake passage through which intake air flows in the direction of the central axis, and an air inlet portion (intake port) for sucking intake air from an air cleaner through an intake duct ( And an air outlet for allowing intake air to flow into the intake port of the engine via the intake pipe. A bracket mounting base 41 is integrally formed on the outer wall surface of the throttle body 7. The accelerator bracket 1 is fastened and fixed to the bracket mounting base 41 by using a screw 42 such as a fastening screw.

  Here, in the throttle body 7, a predetermined range of the throttle bore wall surface (bore inner diameter surface) 10 that forms a gap with the outer peripheral end surface portion 34 of the disc-shaped portion 33 of the throttle valve 5 is shown in FIG. As shown in FIG. 5, a reference surface (reference part) 51 having a predetermined radius of curvature centering on the central axis of the throttle bore 9, and a minute line protruding inward in the radial direction from the reference part 51. Convex portion (for example, acute protrusion, convex contact portion: minute protrusion) 52, and minute streak recess (for example, acute groove portion) recessed outward in the radial direction from the reference portion 51. , A concave contact portion: a minute groove portion) 53. A sawtooth-like uneven shape in which a large number of concave and convex portions are alternately repeated in the order of 53 is integrally formed with a resin material.

  In addition, the reference portion 51 and the minute groove portion 53 are disposed in the throttle body 7 before the bore inner surface 10 of the throttle body 7 is deformed so as to correspond to the outer diameter shape of the outer peripheral end surface portion 34 of the disc-shaped portion 33 of the throttle valve 5. Even when the bore inner diameter surface 10 of the body 7 and the outer peripheral end surface portion 34 of the throttle valve 5 are pressed against each other, a minute gap is formed between the bore inner diameter surface 10 of the throttle body 7 and the outer peripheral end surface portion 34 of the throttle valve 5. The radius of curvature is such that it does not directly contact (mechanical touch) with the outer peripheral end surface portion 34 of the throttle valve 5. On the other hand, the tip end portion (pointed end portion) of the minute projection 52 deforms the bore inner diameter surface 10 of the throttle body 7 so as to correspond to the outer diameter shape of the outer peripheral end surface portion 34 of the disc-like portion 33 of the throttle valve 5. Before, when the bore inner diameter surface 10 of the throttle body 7 and the outer peripheral end surface portion 34 of the throttle valve 5 are pressed against each other, the curvature is such that the outer peripheral end surface portion 34 of the throttle valve 5 is in direct contact (mechanical touch). Has a radius.

[Heating deformation method of Example 1]
Next, a heating deformation method by the laser apparatus of the present embodiment will be briefly described with reference to FIGS.

First, in the throttle bore 9 of the throttle body 7, after fitting the valve side fitting portion 12 of the throttle valve 5 on the outer periphery of the shaft side fitting portion 11 of the throttle shaft 4, a thermal welding method such as laser welding is performed. The throttle body assembly fixed by use is assembled to a jig of a laser device (not shown). Further, the laser device collects the laser beam output from the laser oscillator with a lens or the like, and irradiates the outer peripheral edge of the disc-shaped portion 33 of the throttle valve 5 obliquely. As the laser oscillator, a semiconductor laser oscillator having a laser output of about 20 W to 30 W is used. As the laser oscillator, other laser oscillators such as a pulse YAG (yttrium, aluminum, garnet) laser, a CO ₂ laser, and the like may be used. Further, the moving speed of the jig is set to about 10 mm / sec.

  A jig that holds one end of the throttle shaft 4 in the axial direction while irradiating laser light obliquely from the laser oscillator of the laser device to the outer peripheral edge of the disc-like portion 33 of the throttle valve 5, The rotation angle of the throttle shaft 4 is further pressed in the fully closed direction. In addition, the jig for holding the throttle body 7 is moved in the rotational direction with a rotational radius about the inside diameter of the throttle bore, and while being slightly reciprocated in the radial direction of the disc-like portion 33 of the throttle valve 5, The laser beam is irradiated obliquely on the outer peripheral edge of the disk-shaped part 33. As a result, the laser light is incident on the outer peripheral edge of the disc-shaped portion 33 of the throttle valve 5, passes through this portion, reaches the bore inner diameter surface 10 of the throttle body 7, and is absorbed. The minute projection 52 is melted by this laser irradiation and the pressure contact force that presses the outer peripheral end surface 34 of the throttle valve 5 against the minute projection 52 provided on the bore inner diameter surface 10 of the throttle body 7.

  At this time, the throttle valve 5 is located at a position where the bore inner surface 10 of the throttle body 7 and the outer peripheral end surface portion 34 of the throttle valve 5 are in direct contact and in the vicinity of a position perpendicular to the axial direction of the throttle bore 9. By opening and closing the throttle valve 5, the throttle valve 5 swings around the rotation center axis of the throttle shaft 4 while the outer peripheral end surface portion 34 of the throttle valve 5 is gnawed at the tip portion (pointed portion) of the minute projection 52. (See FIG. 4 (a)). For this reason, the tip end portion (pointed end portion) of the minute projection portion 52 in the molten state is thermally deformed so as to follow the outer diameter shape of the outer peripheral end surface portion 34 of the throttle valve 5, and is perpendicular to the axial direction of the throttle bore 9. Between the outer peripheral end surface portion 34 of the throttle valve 5 and the bore inner diameter surface 10 of the throttle body 7 in the vicinity of a certain position, there is a minute gap so that the outer peripheral end surface portion 34 of the throttle valve 5 does not bite the bore inner diameter surface 10 of the throttle body 7. Is formed (see FIG. 4B).

[Idle opening adjusting method of embodiment 1]
Next, a method for adjusting the idle opening of the intake air throttle device for the internal combustion engine of the present embodiment will be briefly described with reference to FIGS.

  As described above, the outer peripheral end surface portion 34 of the throttle valve 5 is located between the outer peripheral end surface portion 34 of the throttle valve 5 and the bore inner surface 10 of the throttle body 7 in the vicinity of the position perpendicular to the axial direction of the throttle bore 9. Since a minute gap is formed so as not to bite the bore inner surface 10 of the throttle body 7, the return spring 6 is arranged on the outer peripheral side of the throttle shaft 4 and between the back surface of the accelerator lever 3 and the outer wall surface of the throttle body 7. When mounted in the middle, the fully closed stopper portion 14 of the accelerator lever 3 integrated with one end of the throttle shaft 4 in the axial direction is directly applied to the fully closed stopper 15 of the accelerator bracket 1 by the urging force of the return spring 6. Further rotating operation in the fully closed direction is restricted at the contacted position.

  Then, in the state where the coiled compression spring 8 is fitted on the outer periphery of the cylindrical portion of the bolt shaft portion of the idle opening adjusting bolt 2, the male screw portion 17 of the bolt shaft portion of the idle opening adjusting bolt 2 is connected to the accelerator bracket. The idle opening adjustment is adjusted to the screw hole of the fully closed stopper 15 by being screwed into the screw hole of the fully closed stopper 15 and rotating the idle opening adjusting bolt 2 in the normal rotation direction with respect to the tightening direction. Tighten the bolt shaft part of the bolt 2 to the maximum. In other words, the lower end surface of the cylindrical portion of the bolt shaft portion of the idle opening adjusting bolt 2 is screwed in until it comes into contact with the upper end surface of the fully closed stopper 15. As a result, the lower end portion (tip portion) of the male screw portion 17 of the idle opening adjusting bolt 2 protrudes from the lower end surface of the fully closed stopper 15 to the fully closed stopper portion 14 side of the accelerator lever 3 most.

  Next, a minute gap between the outer peripheral end surface portion 34 of the throttle valve 5 and the bore inner diameter surface 10 of the throttle body 7 so that the outer peripheral end surface portion 34 of the throttle valve 5 does not bite the bore inner diameter surface 10 of the throttle body 7, That is, a fine gap is formed so that a predetermined fully closed leakage air amount can be obtained when the throttle valve 5 is fully closed (during idle operation), that is, the rotation angle of the throttle valve 5 is the axis of the throttle bore 9. By rotating the idle opening adjustment bolt 2 in the reverse direction with respect to the tightening direction so that the rotation angle is near the position perpendicular to the direction, the outer peripheral end surface portion 34 of the throttle valve 5 during idle operation And the bore inner surface 10 of the throttle body 7 can be set to a very narrow minimum gap.

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

  When a driver operates a throttle operating part such as a throttle lever or a throttle handle of a vehicle such as a two-wheeled vehicle, the accelerator lever 3 mechanically connected to the throttle operating part via a wire cable causes the urging force of the return spring 6 to act. Against this, it rotates in the forward rotation direction by a predetermined rotation angle corresponding to the throttle operation amount. As a result, the throttle shaft 4 that rotates integrally with the accelerator lever 3 rotates by a predetermined rotation angle, and the throttle valve 5 is opened in the throttle bore 9 of the throttle body 7 by a predetermined rotation angle. Accordingly, since the throttle valve 5 opens the intake passage by a predetermined rotation angle corresponding to the throttle operation amount, the intake air enters the combustion chamber of the engine from the air cleaner via the intake duct, the throttle body 7 and the intake pipe and the intake port of the engine. Is inhaled. As a result, the engine rotation speed is changed to a speed corresponding to the throttle operation amount.

  Conversely, when the driver returns the throttle operating part such as the throttle lever or the throttle handle, the accelerator lever 3, the throttle shaft 4 and the throttle valve 5 are returned to the fully closed direction by the urging force of the return spring 6. At this time, the fully closed stopper portion 14 of the accelerator lever 3 directly contacts the lower end portion (tip portion) of the male screw portion 17 of the idle opening adjusting bolt 2 held by the fully closed stopper 15 of the accelerator bracket 1. The accelerator lever 3 is rotated by the urging force of the return spring 6 until it comes into contact. Accordingly, the idle opening adjusting bolt 2 held by the fully closed stopper 15 restricts further rotation of the accelerator lever 3, the throttle shaft 4 and the throttle valve 5, so that the throttle valve 5 is brought to the fully closed position. Retained. As a result, the intake passage of the throttle body 7 is closed while leaving a gap for obtaining a predetermined fully closed intake air flow rate when the throttle valve 5 is fully closed (idle operation). The amount of intake air sucked into the engine cylinder during idle operation becomes an appropriate value, and the engine rotation speed becomes a desired idle rotation speed. As a result, for example, even a motorcycle (two-wheeled vehicle) without a clutch such as a scooter does not start against the driver's will, and the safety of the vehicle can be improved.

[Effect of Example 1]
As described above, in the intake throttle device for the internal combustion engine of the present embodiment, the accelerator lever 3, the throttle shaft 4, the throttle valve 5 and the throttle body 7 are all made of resin (for example, heat) for the purpose of weight reduction and cost reduction. The resin is integrally formed with a resin material such as a plastic resin. When the outer peripheral end surface portion 34 of the throttle valve 5 is brought into pressure contact with the bore inner surface 10 of the throttle body 7 against the resin inner bore inner surface 10 of the throttle body 7, the outer peripheral end surface portion 34 of the throttle valve 5 and the throttle body 7 The reference portion 51, the minute protrusions 52, and the minute groove portions 53 for reducing the contact area with the bore inner diameter surface 10 are integrally formed so that many irregularities are alternately repeated. As a result, the throttle valve 5 is rotated so as to be closed in the fully closed direction around the rotation axis of the throttle shaft 4, and the outer peripheral end face portion 34 of the throttle valve 5 is brought into pressure contact with the bore inner diameter surface 10 of the throttle body 7. Since the contact area between the outer peripheral end surface portion 34 of the throttle valve 5 and the bore inner diameter surface 10 of the throttle body 7 can be reduced, the tips of a large number of minute protrusions 52 provided on the bore inner diameter surface 10 of the throttle body 7 can be reduced. Since the portion (pointed end portion) is crushed and can be easily thermally deformed, and an excessive pressure contact force is unnecessary, it is possible to prevent unnecessary deformation from being applied to the bore inner diameter surface 10 of the throttle body 7. .

  In the intake throttle device for the internal combustion engine of the present embodiment, when the throttle valve 5 is fully closed, the rotation angle of the throttle valve 5 is the same as that of the outer peripheral end surface portion 34 of the throttle valve 5 with respect to the axial direction of the throttle bore 9. The rotation angle is set so as to approach the vertical as much as possible within the range where the bore inner surface 10 of the throttle body 7 does not directly contact. At this time, as described above, the inner diameter shape of the bore inner diameter surface 10 of the resinized throttle body 7 is thermally deformed so as to follow the outer diameter shape of the outer peripheral end surface portion 34 of the throttle valve 5. Even when a resin material having a relatively poor molding accuracy is used as the material of the throttle body 5 and the throttle body 7, the rotation angle of the throttle valve 5 is made closer to the axis direction of the throttle bore 9 than the current fully closed position. However, since it is possible to prevent the outer peripheral end surface portion 34 of the throttle valve 5 from biting (or galling) the bore inner surface 10 of the throttle body 7, it is possible to prevent the opening / closing operation of the throttle valve 5 from being disabled. The gap between the outer peripheral end face 34 of the throttle valve 5 and the bore inner diameter face 10 of the throttle body 7 can be narrowed to the minimum necessary gap. Rukoto can. Therefore, the amount of air leaked when the throttle valve 5 is fully closed can be further reduced as compared with the current one, so that the demand for fuel consumption reduction can be satisfied. Here, a gap remains between the outer peripheral end surface portion 34 of the throttle valve 5 and the bore inner diameter surface 10 of the throttle body 7 in the portion that could not be deformed, but the air passage formed by the gap is a labyrinth. Because of the shape (see FIG. 5), the amount of intake air passing through the actual gap can be suppressed.

  Here, a coating agent (such as molybdenum disulfide) for filling a minimum gap between the outer peripheral end surface portion 34 of the throttle valve 5 and the bore inner diameter surface 10 of the throttle body 7, or the outer peripheral end surface portion 34 of the throttle valve 5 and the throttle A coating agent (fluorine-based resin or the like) that reduces sliding resistance with the bore inner surface 10 of the body 7 is applied to or coated on the outer peripheral end surface portion 34 of the throttle valve 5 or the bore inner surface 10 of the throttle body 7. May be. In this case, the contact surface between the coating agent and the outer peripheral end surface portion 34 of the throttle valve 5 or the bore inner diameter surface 10 of the throttle body 7 increases, so that the coating agent and the outer peripheral end surface portion 34 of the throttle valve 5 or the throttle body 7 Adhesion with the bore inner diameter surface 10 is improved, and the coating agent is hardly peeled off from the outer peripheral end surface portion 34 of the throttle valve 5 or the bore inner diameter surface 10 of the throttle body 7. Examples of the fluorine-based resin include tetrafluoroethylene resin (PTFE), poly (ethylene trifluoride) chloride (PCTFE), polyvinylidene fluoride (PVDF), polyvinyl fluoride (PVF), and polytetrafluorohexafluoride. One or more coating agents of ethylene (FEP), ethylene-tetrafluoroethylene resin (ETFE), and tetrafluoride-perfluoroalkyl vinyl ether resin (PFA) are desirable.

[Modification]
In this embodiment, as a valve driving means for driving the throttle valve 5 in a fully open direction or a fully closed direction, an operation amount (throttle operation amount) of a throttle lever or a throttle handle of a two-wheeled vehicle is mechanically controlled via a wire cable. 4 is transmitted to an accelerator lever (rotating body) 3 integrated at one end of the valve 4 so that the throttle valve 5 is rotated at a predetermined valve angle (valve opening degree, rotation angle) corresponding to the throttle operation amount. Although the drive means is adopted, the rotation output of an actuator such as a drive motor is transmitted to a valve gear (rotary body) integrated with one end of the throttle shaft 4 so that the throttle valve 5 corresponds to the throttle operation amount. Valve drive means designed to rotate at a predetermined valve angle (valve opening, rotation angle) It may be adopted. Further, the fully closed stopper may be integrally formed on the throttle bore wall surface (bore inner diameter surface) of the throttle body 7 by resin molding.

  In this embodiment, the present invention changes the valve angle (valve opening, rotation angle) of the throttle valve 5 in accordance with the operation amount (throttle operation amount) of the throttle lever or throttle handle of the two-wheeled vehicle. Although an example in which the present invention is applied to an intake throttle device for an internal combustion engine of an automobile has been described, the present invention is applied to a valve angle (valve opening degree, valve opening, The present invention may be applied to an intake throttle device for an internal combustion engine of a four-wheeled vehicle that changes the rotation angle).

  In this embodiment, the valve side fitting portion 12 of the throttle valve 5 is fixed to the outer periphery of the valve fixing portion of the shaft side fitting portion 11 of the throttle shaft 4 by heat welding. The valve side fitting portion 12 of the throttle valve 5 may be integrally formed on the outer periphery of the side fitting portion 11 by resin molding. Further, the throttle shaft (metal shaft) 4 may be directly insert-molded inside the valve side fitting portion 12 of the throttle valve 5. Further, the throttle valve 5 is throttled by using a fastener such as a fastening screw in a state where the throttle valve 5 is inserted into a valve insertion hole formed in a valve fixing portion of the throttle shaft (metal shaft) 4. It may be fastened and fixed to the valve fixing portion of the shaft 4.

  In addition, the biting property (coupling performance) between the outer periphery of the metal shaft 31 of the throttle shaft 4 and the inner periphery of the shaft side fitting portion (resin shaft) 11 of the throttle shaft 4 is improved, and the metal shaft 31 For the purpose of preventing relative movement of the shaft side fitting portion 11 in the axial direction, that is, for the purpose of preventing the metal shaft 31 from coming off from the shaft side fitting portion 11, the cylindrical diameter of the metal shaft 31. A part or all of the outer peripheral surface of the small part may be knurled. For example, a notch or an uneven portion may be formed on a part or all of the outer peripheral surface of the cylindrical small diameter portion of the metal shaft 31.

  Further, as a material for integrally molding the accelerator lever 3, the throttle shaft 4, the throttle valve 5, and the throttle body 7, a resin material that is heated and melted (for example, a molten resin made of a thermoplastic resin) is filled with a filler (for example, a low cost). Glass fiber, carbon fiber, aramid fiber, boron fiber, etc.) or a resin-based composite material mixed with an additive (for example, polybutylene terephthalate containing 30% glass fiber: PBTG30, or polybutylene terephthalate containing 40% glass fiber) : PBTG40) may be used. Also, by injecting the resin-based composite material from the gate into the cavity of the resin molding die, the resin throttle body, the resin accelerator lever, the resin throttle shaft, or the resin throttle valve is formed by injection molding of the resin-based composite material. May be manufactured. The resin molded product integrally molded by injection molding of the resin-based composite material thus manufactured is low in cost and excellent in resin moldability, and has mechanical properties, strength, rigidity, heat resistance, etc. Performance is improved.

  In this embodiment, a resin material (for example, a molten resin made of a thermoplastic resin) is used as a molten material that is heated and melted. However, a molten metal material (for example, an aluminum alloy) is used as a molten material that is heated and melted. Alternatively, a melt of a semi-molten alloy material such as a magnesium alloy may be used. That is, any one or more of the accelerator lever 3, the throttle shaft 4, the throttle valve 5, and the throttle body 7 may be metallized. However, when the minute protrusion 52 and the minute groove 53 are provided on the outer peripheral end surface portion 34 of the throttle valve 5, the throttle body 7 may be metalized, and the minute protrusion on the bore inner diameter surface 10 of the throttle body 7. When the portion 52 and the minute groove portion 53 are provided, the throttle valve 5 may be metalized.

  Further, in this embodiment, a large number of irregularities are alternately formed on the bore inner diameter surface 10 of the throttle body 7 with a reference portion 51, minute protrusions (convex contact portions) 52 and minute groove portions (concave contact portions) 53. Although it was provided so as to be repeated, a large number of only one of a minute protrusion (convex contact portion) 52 or a minute groove (concave contact portion) 53 was provided on the bore inner surface 10 of the throttle body 7. May be. Further, a minute protrusion (convex contact portion) 52 or a minute groove (concave contact portion) 53 is directly connected to the outer peripheral end surface portion 34 of the throttle valve 5 and the bore inner surface 10 of the throttle body 7 when they are in pressure contact. You may make it provide only in the site | part which contacts.

(A) is the side view which showed the whole structure of the intake throttle device for internal combustion engines, (b) is the front view which showed the whole structure of the intake throttle device for internal combustion engines, (c) is the intake throttle device for internal combustion engines (Example 1) which is the top view which showed the whole structure. (A) is AA sectional drawing of FIG.1 (b), (b) is BB sectional drawing of FIG.1 (c) (Example 1). FIG. 3 is a cross-sectional view showing a fully closed state of the throttle valve (Example 1). (A) is sectional drawing which showed the internal diameter shape of the bore internal surface before a deformation | transformation, (b) is sectional drawing which showed the internal diameter shape of the bore internal surface after a deformation | transformation (Example 1). (Example 1) which is the enlarged view which showed the clearance gap between the bore | bore internal-diameter surface of a throttle body, and the outer peripheral end surface part of a throttle valve when a throttle valve is fully closed. (A) is explanatory drawing which showed the heat deformation process, (b) is the enlarged view which showed the external shape of the outer peripheral end surface part of the throttle valve after a deformation | transformation (conventional technique).

Explanation of symbols

2 Idle opening adjustment bolt (Idle opening adjustment screw)
4 Throttle shaft 5 Throttle valve 7 Throttle body 9 Throttle bore 10 Bore inner diameter surface (throttle bore wall surface)
33 Throttle valve disc part 34 Throttle valve outer peripheral face part 51 Reference face (reference part)
52 Minute protrusions (sharp protrusions, minute streak protrusions, convex contact parts)
53 Minute groove (sharp groove, minute streak, concave contact)

Claims (7)

(A) a throttle body having a throttle bore communicating with the combustion chamber of the internal combustion engine;
(B) a shaft having a rotation center axis in a direction substantially perpendicular to an axial direction of the throttle bore or an average flow direction of intake air;
(C) The shaft is integrally assembled with the shaft, and the rotation angle is changed from the fully closed position where the intake air amount becomes the minimum to the fully open position where the intake air amount becomes the maximum, thereby flowing in the throttle bore. In an intake throttle device for an internal combustion engine comprising a throttle valve for adjusting the flow rate of intake air,
Either the throttle bore wall surface of the throttle body or the outer peripheral end surface portion of the throttle valve that is in direct contact with the throttle bore wall surface is made of resin.
When either the throttle bore wall surface or the outer peripheral end surface portion of the throttle valve is in direct contact with the throttle bore wall surface and the outer peripheral end surface portion of the throttle valve, the throttle bore wall surface and the outer periphery of the throttle valve An intake throttle device for an internal combustion engine, wherein a convex or concave contact portion for reducing a contact area with the end surface portion is provided. The intake throttle device for an internal combustion engine according to claim 1,
The convex or concave contact portion is
While directly contacting the throttle bore wall surface and the outer peripheral end surface portion of the throttle valve,
When the shape of either the throttle bore wall surface or the outer peripheral end surface portion of the throttle valve is deformed so as to follow the shape of the other one of the throttle bore wall surface or the outer peripheral end surface portion of the throttle valve,
An intake throttle device for an internal combustion engine, comprising: a minute projection or a minute groove for reducing a contact area between the throttle bore wall surface and an outer peripheral end surface of the throttle valve. The intake throttle device for an internal combustion engine according to claim 2,
The minute protrusions or the minute grooves are provided in a sawtooth shape so that irregularities are alternately repeated on the wall surface of the throttle bore.
The minute protrusion is a minute streaky protrusion that protrudes inward in the radial direction from a reference surface having a predetermined radius of curvature centered on the central axis of the throttle bore,
The intake for an internal combustion engine, wherein the minute groove is a minute streak that is recessed outward in the radial direction from a reference surface having a predetermined radius of curvature centering on a central axis of the throttle bore. Aperture device. The intake throttle device for an internal combustion engine according to claim 2 or 3,
The minute protrusions or the minute grooves are provided in a sawtooth shape so as to alternately repeat irregularities on the outer peripheral end surface of the throttle valve,
The minute protrusion is a minute streaky protrusion that protrudes outward in the radial direction from a reference surface having a predetermined radius of curvature centered on the rotation center axis of the shaft,
The intake for an internal combustion engine, wherein the minute groove is a minute streak recessed inward in a radial direction from a reference surface having a predetermined radius of curvature centering on the rotation center axis of the shaft. Aperture device. The intake throttle device for an internal combustion engine according to any one of claims 2 to 4,
The minute projections are deformed so that the shape of either the throttle bore wall surface or the outer peripheral end surface portion of the throttle valve follows the shape of the throttle bore wall surface or the outer peripheral end surface portion of the throttle valve. A radius of curvature that directly contacts the outer peripheral end surface of the throttle valve or the throttle bore wall surface in a state prior to the operation, and the minute groove portion includes the throttle bore wall surface or the outer peripheral end surface of the throttle valve. In a state before the shape of either one of the throttle bore wall surface or the outer peripheral end surface portion of the throttle valve is deformed so as to follow the other shape, and the outer peripheral end surface portion of the throttle valve or the throttle bore wall surface For internal combustion engines characterized by having a radius of curvature that does not contact directly Inlet throttle device. The intake throttle device for an internal combustion engine according to any one of claims 1 to 4,
A substantially annular rotary drive that changes the rotation angle of the throttle valve via the shaft;
The throttle body has a locking portion for restricting the rotation operation of the throttle valve in the fully closed direction at the fully closed position by directly or indirectly contacting the rotary drive body,
The throttle valve includes an outer peripheral end surface portion of the throttle valve and a throttle bore wall surface with respect to the axial direction of the throttle bore when the rotary drive body directly or indirectly contacts the locking portion. An intake throttle device for an internal combustion engine, wherein the rotation angle is set so as to approach the vertical as much as possible within a range in which the engine does not directly contact. The intake throttle device for an internal combustion engine according to claim 6,
The throttle valve includes an outer peripheral end surface portion of the throttle valve, a throttle bore wall surface, and a throttle bore wall surface in order to obtain a predetermined amount of leakage air when the rotary drive body abuts directly or indirectly on the locking portion. An intake throttle device for an internal combustion engine, wherein the rotation angle is set so that a minute gap can be formed between them.

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