JP4733171B2 - Intake device for internal combustion engine - Google Patents

Description

  The present invention relates to an intake device for an internal combustion engine having a throttle body in which a throttle valve is disposed in an intake passage.

  An intake device attached to a spark ignition internal combustion engine (for example, an automobile engine) is a throttle device for controlling the amount of intake air flowing into the combustion chamber, or for introducing intake air that has passed through the throttle device into the combustion chamber. It consists of the intake pipe etc. The throttle device includes a throttle body and a throttle valve that is rotatably held in a bore of the throttle body. Normally, the throttle device is connected to an intake manifold, and a continuous intake passage is formed by the bore of the throttle body and the bore of the intake manifold.

  In recent years, a technique for manufacturing a throttle body and a throttle valve constituting an intake device by resin injection molding has been developed for reasons such as weight reduction of parts and improvement of productivity. For example, a throttle body mounted on an intake manifold of an internal combustion engine, which includes a resin throttle body and a throttle valve. The air flow path and the throttle valve are provided such that the maximum width of each is larger than the maximum height. Is known (see Patent Document 1).

Japanese translation of PCT publication No. 2004-512451

  By the way, in order to realize good intake control in the intake device, it is desired to accurately form a throttle bore that defines an intake passage. In particular, when the throttle body is resin-molded, it becomes difficult to accurately manage the throttle bore due to molding shrinkage based on the difference in orientation of the reinforcing fibers contained in the resin material.

  However, although the prior art described in the above-mentioned Patent Document 1 aims at improving intake control, it pays attention to the bending of the throttle valve, and improvement in the accuracy of the throttle bore cannot be expected. Further, in the configuration in which the maximum width of the air flow path is larger than the maximum height as in the above prior art, the distance between the bearings supporting both sides of the rotary shaft of the throttle valve is increased, so that the coaxial accuracy is lowered and is rather good. Inspiratory control could be hindered.

  The present invention has been devised in view of such problems of the prior art, and provides an intake device for an internal combustion engine that can improve the coaxial accuracy of the throttle valve when the throttle body is resin-molded. The purpose is to provide.

A first invention made to solve the above-described problem is that a resin throttle body (12) having a first intake passage (10) having a throttle bore (11) is formed, and a rotation shaft is provided on the throttle body. And a throttle valve (14) used for throttle control of the first intake passage. The throttle bore has an elliptical cross section, and the major axis of the ellipse is The throttle body is formed of a resin material containing reinforcing fibers, and the longitudinal direction of the reinforcing fibers is orthogonal to the long axis of the ellipse.

In the second aspect of the invention, the intake member (3) having the second intake passage (42) communicating with the first intake passage, and either the throttle body or the intake member are protruded. In addition, a male screw (43) is formed on the outer peripheral surface, and a connection pipe (41) provided for connection between the first intake passage and the second intake passage, and the other of the throttle body and the intake device And a connecting pipe holding portion (15) in which a female screw (45) screwed with the male screw is formed on the inner peripheral surface.

According to a third aspect of the present invention, the connecting pipe has a substantially circular inner cross section continuous to the first intake passage, and the first intake passage extends from the throttle bore toward the connecting pipe. It can be set as the structure which changes gradually from the said ellipse to the said substantially perfect circle.

According to the first aspect of the invention, even when the throttle body is resin-molded, the coaxial accuracy can be improved by shortening the distance between the bearings that support the rotary shaft of the throttle valve by making the throttle bore elliptical. it can. Further , since the molding shrinkage rate in the longitudinal direction of the reinforcing fiber in the throttle body is smaller than the direction orthogonal to the longitudinal direction, the longitudinal direction of the reinforcing fiber is orthogonal to the major axis of the ellipse (that is, the longitudinal direction of the reinforcing fiber). The direction in which the molding shrinkage rate increases becomes the elliptical long axis direction of the highly rigid throttle bore, improving the accuracy of the throttle bore and further improving the coaxial accuracy. Can be made. According to the second aspect of the present invention, the connecting pipe and the connecting pipe holding portion are screwed together, thereby avoiding deformation of the throttle bore that may occur when the resin throttle body and the intake member are bolted. It becomes possible to do. According to the third invention, even when the second intake passage has a substantially circular cross section, the shape of the intake passage is prevented from changing suddenly from the first intake passage to the second intake passage. Smooth air intake flow can be maintained.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a perspective view of an intake device according to a first embodiment of the present invention, FIG. 2 is a longitudinal sectional view of a main part of the intake device of FIG. 1, and FIG. FIG.

  As shown in FIG. 1, the intake device 1 of this embodiment includes an electronic control throttle device 2 and an intake manifold (intake member) 3 connected to the downstream side of the electronic control throttle device 2 as main components. The upstream end of the electronically controlled throttle device 2 is connected to the downstream end of an intake duct 4 communicating with an air cleaner (not shown), and the downstream end of the intake manifold 3 is an in-line 4-cylinder gasoline engine (hereinafter abbreviated as an engine) E for automobiles. The cylinder head E1 is connected via an injector base (not shown).

  The electronically controlled throttle device 2 includes a motor 5 that rotationally drives a throttle valve 14 (see FIG. 2), and a gear box (deceleration mechanism) that decelerates the rotational output of the motor 5 and transmits it to the rotating shaft 14a of the throttle valve 14. 6 are provided. The motor 5 is driven and controlled by an ECU (not shown). The intake manifold 3 is provided with a negative pressure actuator 7 of a variable intake mechanism. The intake manifold 3 is provided with a negative pressure actuator 7 of a variable intake mechanism.

  2 and 3, the electronically controlled throttle device 2 includes a throttle body 12 in which an intake passage 10 (first intake passage) having a throttle bore (hereinafter abbreviated as a bore) 11 is formed. ing. The throttle body 12 is an injection-molded product made of a resin material containing reinforcing fibers (carbon fiber, glass fiber, etc.), and is provided on a cylindrical portion 12a connected to the intake duct 4 and one end side of the cylindrical portion 12a. It has a housing portion 5a of the motor 5 and a flange portion 12b in which the gear box 6 is integrated. Around the bore 11 in the flange portion 12b, four bolt holes 13 are provided at an angular interval of 90 °. Further, the throttle valve 14 provided in the throttle body 12 is rotatably held at both ends of a rotary shaft 14a by bearings 16 (see FIG. 4). The throttle valve 14 has a substantially disc-shaped butterfly valve body 14b corresponding to the cross-sectional shape of the bore 11, and is used for intake air amount control of the engine E by opening and closing the bore 11 based on the turning operation. The The bore 11 has an elliptical cross section perpendicular to the direction in which the intake passage 10 extends, so that the major axis direction of the ellipse indicated by line A in FIG. 3 is orthogonal to the direction of the rotary shaft 14 a of the throttle valve 14. Has been placed.

  In this way, the bore 11 has an elliptical shape, and the long axis direction of the ellipse is arranged so as to be orthogonal to the direction of the rotating shaft 14a of the throttle valve 14, thereby shortening the distance between the bearings 16 that support the rotating shaft 14a. Thus, even when the throttle body 12 is resin-molded, the coaxial accuracy can be improved. In addition, since the rigidity of the direction of the rotating shaft 14a (the minor axis direction of the ellipse) in the throttle body 12 is enhanced by the arrangement of the bearing 16 and the rotating shaft 14a, the major axis direction of the ellipse is set to the direction of the rotating shaft 14a of the throttle valve 14. By arranging them so as to be orthogonal to the direction, there is an advantage that the balance of rigidity in the major axis direction and the direction of the rotating shaft 14a is improved. Since the bore 11 has an elliptical shape, the distance X between the bolt holes 13 in the direction of the rotation shaft 14a can be shortened as compared to the distance Y in the major axis direction of the ellipse as shown in FIG. Thus, the throttle body 12 can be reduced in weight and size.

  The intake manifold 3 is a resin injection-molded product similar to the throttle body 12 and has a substantially square connection flange (intake member) 15 to which the electronic control throttle device 2 is connected. As shown in FIG. 2, the connection flange 15 is formed with an intake passage 20 connected to the intake passage 10 of the throttle body 12, and a metal nut (see FIG. (Not shown) is inserted. The throttle body 12 is fastened to the connection flange 15 of the intake manifold 3 by a flange bolt 23 (see FIG. 1) with a spacer 21 and a plate packing 22 interposed between the throttle body 12 and the intake manifold 3. A ring-shaped packing 25 is fitted in the annular groove 24 formed on the end face of the connection flange 15.

  4 and 5 are a schematic longitudinal sectional view and a transverse sectional view showing an outline of the injection molding method of the throttle body 12 in FIG. 1, respectively. 4 and 5, a schematic image of the orientation of the reinforcing fibers contained in the resin material is indicated by a plurality of parallel lines (hatching).

  When the throttle body 12 is injection-molded, an outer peripheral portion of the flange portion 12b of the throttle body 12 (more specifically, a position corresponding to one side of the rotary shaft 14a of the throttle valve 14) in a molding die (not shown). The gate 31 is arranged on the lower end side (the intake manifold 3 side). As shown in FIG. 5, the gate 31 is arranged wider than the long axis of the bore 11. With such a configuration, in the lower part of the throttle body 12 where the bore 11 is disposed (particularly, the flange portion 12b), the molten resin material is injected into the mold cavity substantially parallel to the rotary shaft 14a of the throttle valve 14. Is done. As a result, as shown in FIGS. 3 and 4, at the lower part of the throttle body 12, the reinforcing fibers contained in the resin material have a longitudinal direction (resin flow direction) orthogonal to the major axis direction of the ellipse or Oriented to intersect. In this case, the bearing 16 can be insert-molded or press-fitted after the throttle body 12 is molded.

  Thus, by orienting the reinforcing fibers so that the longitudinal direction thereof is orthogonal to or intersecting with the long axis of the ellipse, the molding shrinkage rate (for example, 0.15) in the direction of the rotation shaft 14a in the throttle body 12 is It becomes smaller than the molding shrinkage rate (for example, 0.5) in the major axis direction of the ellipse. That is, the direction in which the molding shrinkage rate increases is the elliptical long axis direction of the highly rigid bore 11 in the throttle body 12, thereby improving the accuracy of the bore 11 and further improving the coaxial accuracy of the rotating shaft 14a. Can be made. When the throttle body 12 is not a simple cylinder but has a configuration in which accessories such as the housing 5a of the motor 5 and the gear box 6 are integrated, it is more preferable to ensure the accuracy of the bore 11 better. Since it becomes difficult, the method of optimizing the orientation of the reinforcing fibers as described above is particularly effective.

  In the injection molding method, since the gate 31 can be disposed on the outer peripheral portion of the throttle body 12, the flatness of the lower surface 30 (see FIG. 4) of the throttle body 12 located on the connection flange side of the intake manifold. Can be maintained satisfactorily, and there is an advantage that burrs and deformation at the time of gate cut do not adversely affect the performance of the electronic control throttle device 2.

  FIG. 6 is a longitudinal sectional view of an essential part of an intake device according to the second embodiment of the present invention. Here, the same components as those in the first embodiment are denoted by the same reference numerals, and matters not particularly mentioned are the same as those in the first embodiment.

  As shown in FIG. 6, the intake device 1 of the present embodiment includes a connecting pipe 41 that projects from one side (lower end of the flange portion 12 b) of the throttle body 12. The connection pipe 41 forms an intake passage (second intake passage) 42 whose inner peripheral surface is connected to the intake passage 10, and the intake passage 42 has a substantially circular cross section perpendicular to the extending direction. Further, a male screw (sawtooth screw) 43 having a flank angle on the proximal end side smaller than a flank angle on the distal end side is formed on the outer peripheral surface of the connecting pipe 41. The sawtooth screw is preferably formed with a very small flank angle on the base end side (about 0 to 3 °). Further, a female screw (sawtooth screw) 45 that is screwed with the male screw 43 is provided on the inner peripheral surface of the connecting hole 44 formed in the connecting flange (connecting pipe holding portion) 15 of the intake manifold 3. The male screw 43 has a configuration in which screw threads are provided intermittently in the circumferential direction. An O-ring 47 is fitted in an annular groove 46 provided at the boundary between the outer peripheral surface of the connecting pipe 41 and the main body of the throttle body 12.

  As described above, the configuration in which the connecting pipe 41 and the connection flange 15 are screwed together can avoid deformation of the bore 11 that may occur when the resin throttle body 12 and the intake manifold are bolted together. Further, the bolt holes 13 as in the first embodiment can be omitted or the number thereof can be reduced (see FIG. 7), and the throttle body 12 can be reduced in weight and size. Furthermore, there is also an advantage that tightening distortion and deformation of the flange portion 12b and the bore 11 which can occur in the case of bolt fastening can be avoided. Further, by forming the screws 43 and 45 with sawtooth screws, the fastening state between the connecting pipe 41 and the connection flange 15 can be stably maintained.

  The intake passage 10 of the throttle body 12 has a shape that is gradually biased from an ellipse to a substantially perfect circle from the bore 11 toward the connecting pipe 41. More specifically, the cross-sectional shape of the intake passage 10 is from an ellipse (the shape of the bore 11) to a substantially perfect circle (the shape of the bore 11) from the parting position in the intake passage 10 indicated by line B in FIG. The shape of the intake passage 42 of the connecting pipe 41 is provided so as to gradually change. Thereby, even if the connection flange 15 (intake manifold) has a substantially circular cross section, the shape of the intake passage is prevented from changing suddenly from the intake passage 10 to the intake passage 42, and smooth intake air is prevented. The flow can be maintained.

  Although the present invention has been described in detail based on specific embodiments, these embodiments are merely examples, and the present invention is not limited to these embodiments. For example, the connection between the connecting pipe of the throttle body and the connecting flange of the intake manifold can be realized by a configuration in which a female screw is provided on the inner peripheral surface of the connecting pipe and a male screw is provided on the outer peripheral surface of the connecting pipe holding portion. Can do.

The perspective view of the air intake device which concerns on 1st Embodiment The principal part longitudinal cross-sectional view of the intake device which concerns on 1st Embodiment The principal part cross-sectional view of the intake device which concerns on 1st Embodiment Schematic longitudinal cross-sectional view which shows the outline of the injection molding method of the throttle body which concerns on 1st Embodiment Schematic cross-sectional view showing the outline of the injection molding method of the throttle body according to the first embodiment The principal part longitudinal cross-sectional view of the intake device which concerns on 2nd Embodiment

Explanation of symbols

1 Intake device 2 Electronically controlled throttle device 3 Intake manifold (intake member)
4 intake duct 5 motor 6 gear box 10 intake passage (first intake passage)
11 Throttle bore 12 Throttle body 15 Connection flange 16 Bearing 14 Throttle valve 14a Rotating shaft 31 Gate 41 Connecting pipe 42 Intake passage (second intake passage)
43 Male thread 45 Female thread

Claims (3)

A resin throttle body having a first intake passage having a throttle bore;
A throttle valve that is rotatably supported by the throttle body via a rotation shaft and is used for throttle control of the first intake passage;
The throttle bore has an elliptical cross section, and the major axis of the ellipse is orthogonal to the rotation axis ,
The intake device for an internal combustion engine, wherein the throttle body is made of a resin material containing reinforcing fibers, and the longitudinal direction of the reinforcing fibers is orthogonal to the long axis of the ellipse . An intake member formed with a second intake passage communicating with the first intake passage;
A projecting pipe projecting from one of the throttle body and the intake member and having a male screw formed on an outer peripheral surface thereof, and a connecting pipe provided to connect the first intake passage and the second intake passage;
2. The connecting pipe holding portion according to claim 1 , further comprising a connecting pipe holding portion provided on one of the throttle body and the intake device and having a female screw threadedly engaged with the male screw formed on an inner peripheral surface. An intake device for an internal combustion engine as described. The connecting pipe has a substantially circular shape in the cross section of the inner periphery connected to the first intake passage,
The intake device for an internal combustion engine according to claim 2 , wherein the first intake passage gradually changes from the ellipse to the substantially perfect circle from the throttle bore toward the connection pipe.

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