JP2006090234A - Throttle valve device - Google Patents

Abstract

To improve sealing performance between a throttle valve body and a throttle body.
A throttle valve device includes a throttle valve main body 10 and a throttle body 8 that accommodates the throttle valve main body 10. The throttle valve body 10 includes a shaft portion 12 and a valve portion 11. The valve part 11 has an elastic part 21 added to the valve part 11 by double molding. The elastic portion 21 extends to the shaft portion 12, and the peripheral edge of the extended portion is formed in a corrugated cross-sectional shape in order to improve the adhesion with the throttle body 8. The shaft portion 12 includes a large diameter portion 13 having a size larger than that of the valve portion 11 and a small diameter portion 14 having a small size.
[Selection] Figure 1

Description

  The present invention relates to a throttle valve device, and more particularly to a throttle valve device having a structure suitable for improving sealing performance.

In order to adjust the output of the internal combustion engine by adjusting the amount of the air-fuel mixture sucked into the combustion chamber of the internal combustion engine, a throttle valve device is incorporated in the carburetor and the electronic fuel injection device. For example, as described in Japanese Utility Model Publication No. 3-112542, a throttle valve device has a butterfly throttle valve body pivotally supported in a throttle chamber or a throttle body. Adjust. In this throttle valve device, the throttle body is made of resin. Japanese Utility Model Laid-Open No. 4-134463 discloses a throttle valve device in which a resin coating or a resin tape is applied to the valve surface in order to prevent icing of water adhering to the throttle valve.
Japanese Utility Model Publication No. 3-112542 Japanese Utility Model Publication No. 4-134463

  A conventional throttle valve main body is divided into a butterfly valve portion and a shaft portion, and these are integrally assembled by a method such as screwing or caulking. Thus, since the butterfly valve part and the shaft part are separated, there is a problem that a large number of assembly steps are required. Also, when the valve is fully closed, the sealing performance may vary due to variations in dimensional tolerances between the throttle valve body and the throttle body, and the air flow rate may need to be adjusted after assembly.

  FIG. 14 is a cross-sectional view of the prior art showing an example of variation in sealing performance due to angular tolerance between the throttle body and the butterfly valve portion. The butterfly valve unit 100 is configured to contact the step 120 of the throttle body 110 to ensure a seal. However, as can be understood from this figure, due to the variation in the step 120 of the throttle body 110, a gap 130 is generated even though the butterfly valve portion 100 is rotated to a predetermined fully closed position.

  FIG. 15 is a cross-sectional view of the prior art showing an example of variation in seal performance due to axial length tolerance between the throttle body and the throttle valve body. The throttle valve body shows only the shaft. As understood from this figure, one (150) of the two surfaces 150, 160 of the throttle valve body 140, which is set so that the throttle valve body 140 and the throttle body 110 are in contact with each other, is in contact with the throttle body 110. The other (160) is not in contact with the throttle body 110, and a gap 170 is generated.

  An object of the present invention is to provide a throttle valve device capable of eliminating the above-described imperfect seal and reducing the number of assembling steps of the throttle valve body.

  In order to achieve the above object, the present invention provides a throttle valve device for an internal combustion engine having a throttle valve body and a throttle body that accommodates the throttle valve body, wherein the throttle valve body is an intake passage portion in the throttle body. A butterfly valve portion that opens and closes and a shaft portion that supports the butterfly valve portion with respect to the throttle body, and the butterfly valve portion is preferably covered with an elastic portion made of an elastic material added by double molding. There is a first feature in this point.

  Further, the present invention has a second feature in that the throttle valve body is formed with a recess and / or a hole into which the elastic material can enter.

  Further, according to the present invention, the elastic portion is extended from the valve portion to the shaft portion, and the extended portion includes a corrugated peripheral edge, and the throttle body is provided with a wall surface against which the peripheral side portion abuts. There is a third feature.

  Further, in the present invention, the butterfly valve portion and the shaft portion are an integral structure made of resin, and the shaft portion has a diameter larger than the maximum dimension of the butterfly valve portion on one side of the butterfly valve portion, The fourth feature is that the other side has a diameter smaller than the maximum dimension.

  According to a fifth aspect of the present invention, the throttle valve body is positioned with respect to the throttle body in a direction along the axis while being loaded on one side along the axis of the shaft. There are features.

  According to the first feature, since the butterfly valve portion is covered with the elastic portion, variation in tolerance of the rotation angle of the valve and variation in tolerance of the shape of the intake passage in the throttle body with which the butterfly valve portion contacts when the throttle is closed. Even if it is large, these variations can be absorbed by the deformation of the elastic portion. Therefore, the sealing performance in the throttle closed state can be improved. The elastic part can be easily added by double molding.

  According to the second feature, since the elastic material enters the recess and / or the hole at the time of molding, the connection between the elastic portion and the throttle valve body is further ensured.

  According to the third feature, the peripheral edge of the waveform contacts the wall surface formed on the throttle body. At this time, since the peripheral portion has a waveform that tends to bend, it can be in close contact with the wall surface in the throttle body to provide high sealing performance.

  According to the fourth feature, since the throttle valve body can be inserted into the throttle body from the small diameter portion, assembly is easy.

  According to the fifth feature, since the load is applied to the throttle valve body in the direction of extension of the axis, the peripheral side portion of the extended portion of the elastic portion can be better pressed against the wall surface of the throttle body. Will improve.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 2 is a sectional view of an essential part of an internal combustion engine including a throttle valve device according to an embodiment of the present invention. In the figure, an intake valve 3 is disposed in an intake port 2 formed in a cylinder head 1 of an internal combustion engine. An intake pipe 4 that introduces an air-fuel mixture into the intake port 2 includes a base 5 coupled to the cylinder head 1, a heat insulator 6 formed of a heat insulating material, an air cleaner case 7, and a throttle body 8. In a portion of the intake pipe 4 formed at the lower part of the air cleaner case 7, a fuel injection valve 9 is disposed with its injection hole directed into the intake pipe 4. The heat insulator 6 prevents the heat from the engine from being directly conducted to the air cleaner 7 and the throttle body 8, and enables the air cleaner case 7 and the throttle body 8 to be formed of a resin material having a relatively low heat resistance. To do.

  The throttle body 8 is incorporated in the air cleaner case 7, and the air purified by an air cleaner body (air filter) (not shown) is expanded at the upper intake port 81 of the throttle body 8 during the intake stroke of the internal combustion engine. To the intake pipe 4. A throttle valve body 10 is pivotally supported on the throttle body 8 so as to be swingable. The throttle valve body 10 includes a butterfly valve portion (hereinafter simply referred to as “valve portion”) 11 and a shaft portion 12 that supports the valve portion 11 on the throttle body 8.

  FIG. 1 is a sectional view of the throttle valve device, and FIG. 3 is a side view thereof. 1 and 3, the shaft portion 12 includes a large-diameter portion 13 located in the upper portion of FIG. 1 and a small-diameter portion 14 located in the lower portion. The cross-sectional shape of the intake pipe at the position where the valve portion 11 and at least the valve portion 11 are arranged is rectangular, and the valve portion 11 abuts against a stepped surface formed in the throttle body 8 when the throttle is closed. This step is formed by shifting the axis of the intake pipe 4 between the upstream side and the downstream side of the valve portion 11 (see the cross-sectional shape of the throttle body 8 in FIG. 2).

  That is, the diameter of the large diameter portion 13 is larger than one side of the rectangle of the valve portion 11 (that is, the maximum dimension of the valve portion in the direction perpendicular to the shaft portion 12), and the diameter of the small diameter portion 14 is the rectangular shape of the valve portion 11. It is set smaller than one side. The valve portion 11 is positioned at an intermediate portion between the large diameter portion 13 and the small diameter portion 14 with both ends coupled to the large diameter portion 13 and the small diameter portion 14. The large-diameter portion 13 is inserted into the sleeve 15 protruding from the throttle body 8, and the small-diameter portion 14 is inserted through the collar 18 into the inner wall 17 of the double sleeve 16 protruding to the opposite side of the sleeve 15. ing. The end of the small diameter portion 14 protrudes from the inner wall 17. A washer 19 is passed through the projecting portion, and a stop ring 20 is fitted therein to prevent the throttle valve body 10 from coming out of the throttle body 8.

  The valve part 11 is provided with an elastic part 21 that covers the valve part 11. The elastic portion 21 includes annular portions 22 and 23 extending from the valve portion 11 to the large diameter portion 13 and the small diameter portion 14, respectively. The peripheral portions of the annular portions 22 and 23 are formed in a corrugated shape in order to bend easily at the portion that contacts the throttle body 8 to improve the adhesion. The elastic part 21 is preferably formed from an elastic polymer. Elastic polymers are materials with excellent chemical resistance. The operation of the elastic portion 21 will be further described later.

  The valve portion 11 and the shaft portion 12 are integrally formed by resin molding. The elastic portion 21 is added to the valve portion 11 and the shaft portion 12 which are resin-molded by molding.

  A torsion spring 24 that biases the shaft portion 12 in the throttle closing direction is provided on the outer periphery of the sleeve 15. One end of the torsion spring 24 is fixed to the base portion of the sleeve 15, and the other end is fixed to the flange portion 25 protruding from the upper portion of the large diameter portion 13. An annular groove 26 is formed along the outer periphery of the flange portion 25, and a throttle cable 27 is attached to the flange portion 25 while being guided by the groove 26. One end of the throttle cable 27 is coupled to the flange portion 25 by a pin 28, and the other end is coupled to an accelerator operation unit (a grip of a steering bar in a motorcycle) (not shown).

  The torsion spring 24 is provided on the shaft portion 12 so as to bias the valve portion 11 in the throttle fully closed direction. The throttle cable 27 is biased by the torsion spring 24 when the throttle cable 27 is pulled. The shaft portion 12 rotates in the opposite direction to be attached to the flange portion 25 so that the throttle is opened.

  When the throttle valve body 10 is assembled to the throttle body 8, the throttle valve body 10 is inserted into the sleeve 15 from the small diameter portion 14 side. Then, after the small diameter portion 14 passes through the inner wall 17 of the sleeve 16 and its end protrudes from the inner wall 17, the washer 19 and the stop ring 20 are fitted into the outer periphery of the end of the small diameter portion 14. Since the throttle valve body 10 includes the large diameter portion 13 and the small diameter portion 14, the throttle body 8 can be easily assembled to the throttle body 8 from one direction.

  The throttle valve body 10 is assembled to the throttle body 8 so that a reliable sealing performance can be obtained by pressing the periphery of the elastic portion 21, particularly the side surface, to the throttle body 8. That is, the stop ring 20 is fitted into the shaft portion 12 in a state where a thrust load is applied by the torsion spring 24 in a direction (direction B described later) directed from the large diameter portion 13 side to the small diameter portion 14 side.

  A connecting shaft 29 for connecting the throttle sensor 28 to the small diameter portion 14 is coupled to the small diameter portion 14. The throttle sensor 28 is a variable resistor, for example, and can detect the throttle opening based on a resistance value corresponding to the rotational position of the connecting shaft 29 coupled to the small diameter portion 14.

  FIG. 4 is a perspective view of the completed throttle valve body 10, and the same reference numerals as those in FIGS. 1 and 3 denote the same parts.

  5-10 is explanatory drawing of the molding method of the throttle valve main body 10 and the elastic part 21. FIG. In the molding, first, as shown in FIG. 5, a mold 30 for molding (injection molding) the throttle valve body 10 excluding the elastic portion 21 is prepared. The mold 30 includes a part 301 and a part 302. A resin 31 is injected into the mold 30 from a resin injection port 303. When the state of FIG. 6 in which sufficient resin 31 has been injected into the mold 30 is reached, the injection is terminated, and the mold 30 is removed after cooling of the resin 31 (withdrawn in the direction of the arrow in FIG. 7).

  A die 33 for integrally adding the elastic portion 21 to the core portion 32 of the throttle valve main body 10 thus completed (that is, the throttle valve main body 10 to which the elastic portion 21 is not added) 32 is prepared (FIG. 8). The mold 33 includes a part 331 and a part 332. When the core portion 32 of the throttle valve body 10 is fitted into the mold 33, a space 34 for the elastic portion 21 is formed as shown in FIG. Therefore, the elastic polymer 36 is injected from the elastic polymer injection port 35. FIG. 10 shows a state where the space 34 is filled with an elastic polymer. When the mold 33 is removed after cooling, the throttle valve body 10 (see FIG. 4) is obtained in which the elastic polymer 36 is integrally added to the core portion 32 of the throttle valve body 10 as the elastic portion 21.

  FIG. 11 is a cross-sectional view showing an engaging portion between the valve portion 11 and the throttle body 8. In the figure, the valve portion 11 is biased in the direction of arrow A by the force of the torsion spring 24 when the throttle is fully closed. Therefore, the edge 211 of the elastic part 21 covering the periphery of the valve part 11 is pressed against the steps 81 and 82 of the throttle body 8. The elastic portion 21 is deformed by being pressed against the steps 81 and 82 and reliably contacts both the surfaces of the steps 81 and 82.

  FIG. 12 is a cross-sectional view showing an engaging portion between the elastic portion 21 and the throttle body 8. In the figure, the throttle valve body 10 is assembled to the throttle body 8 in a state in which a thrust load is applied in the direction of arrow B. Accordingly, the annular portions 22 and 23 of the elastic portion 21 are pressed against the surfaces of the steps 83 and 84 of the throttle body 8 by the thrust load, respectively, and bend. The amount of deflection depends on the tolerance variation of the throttle valve body 10 and the throttle body 8, but in the example of FIG. 2, the annular portion 23 is deflected more than the annular portion 22.

  In FIG. 12, the resin portion 21 has portions 39 and 40 that extend through the large diameter portion 13 and the small diameter portion 14 through holes 37 and 38 formed in the large diameter portion 13 and the small diameter portion 14. . Since the large-diameter portion 13 and the small-diameter portion 14 are sandwiched between the projecting portions 39 and 40 and the annular portions 22 and 23, the elastic portion 21 and the core portion 28 of the throttle valve body 10 are more reliably coupled.

  In order to improve the coupling between the valve part 11 and the elastic part 21, the valve part 11 can also be provided with a hole or a recess into which the elastic polymer can flow during molding. FIG. 13 is a perspective view of the valve portion 11 excluding the elastic portion 21, and a plurality of concave portions 41 are formed on the surface of the valve portion 11. The concave portion 41 may be provided on the surface of the shaft portion 12 where the annular portions 22 and 23 of the elastic portion 21 are in close contact. In addition, it may replace with the recessed part 41 and the hole which penetrates the valve | bulb part 11 may be provided, and the number is not limited. Moreover, a hole and a recessed part may be mixed.

  As described above, according to the present embodiment, the elastic body 21 provided in the valve portion 11 securely seals the throttle valve body 10 and the throttle body 8.

  The shaft portion 12 may have a constant shaft diameter without providing a large-diameter portion in which the shaft diameter on the flange 181 side is increased, or may have a small shaft diameter on the flange 181 side. In that case, in order to allow the throttle valve body 10 to be inserted from one side of the throttle body 8, the bearing (bush) supporting the shaft on the flange 181 side (large diameter portion in FIG. 1) is divided into two parts, that is, the shaft portion. 12 divided by a dividing surface along the longitudinal direction is used.

It is sectional drawing of the throttle valve apparatus which concerns on one Embodiment of this invention. It is sectional drawing of the intake system containing the throttle valve apparatus which concerns on one Embodiment of this invention. It is a side view of a throttle valve device concerning one embodiment of the present invention. 1 is a perspective view of a throttle valve body 10. It is explanatory drawing which shows the molding method of a throttle valve main body and an elastic part. It is explanatory drawing which shows the molding method of a throttle valve main body and an elastic part. It is explanatory drawing which shows the molding method of a throttle valve main body and an elastic part. It is explanatory drawing which shows the molding method of a throttle valve main body and an elastic part. It is explanatory drawing which shows the molding method of a throttle valve main body and an elastic part. It is explanatory drawing which shows the molding method of a throttle valve main body and an elastic part. It is sectional drawing which shows the engaging part of a valve | bulb part and a throttle body. It is sectional drawing which shows the engaging part of an elastic part and a throttle body. It is a perspective view of the valve | bulb part except an elastic part. It is sectional drawing of the conventional apparatus which shows the example of the seal incomplete by the angle tolerance of a throttle body and a butterfly valve part. It is sectional drawing of the conventional apparatus which shows the example of the seal incomplete by the length tolerance of the axial direction of a throttle body and a throttle valve main body.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Cylinder head, 2 ... Intake port, 4 ... Intake pipe, 7 Air cleaner case, 8 ... Throttle body, 10 ... Throttle body main body, 11 ... Valve part, 12 ... Shaft part, 13 ... Large diameter part, 14 ... Small diameter part 15 ... Sleeve, 21 ... Elastic part

Claims (6)

In a throttle valve device for an internal combustion engine having a throttle valve body and a throttle body that houses the throttle valve body,
The throttle valve body comprises a butterfly valve portion that opens and closes an intake passage portion in the throttle body, and a shaft portion that supports the butterfly valve portion with respect to the throttle body,
A throttle valve device, wherein the butterfly valve portion is covered with an elastic portion.   2. The throttle valve device according to claim 1, wherein the elastic portion is fixed to the throttle valve body by a double molding method in which an elastic material is further added by molding on the molded throttle valve body.   The throttle valve device according to claim 2, wherein the throttle valve body is formed with a recess and / or a hole into which the elastic material can enter. The elastic part extends from the valve part to the shaft part, and the extension part includes a corrugated peripheral edge;
The throttle valve device according to any one of claims 1 to 3, wherein the throttle body is provided with a wall surface with which the peripheral side portion abuts. The butterfly valve portion and the shaft portion are an integral structure made of resin,
The shaft portion has a diameter larger than a maximum dimension of the butterfly valve portion on one side of the butterfly valve portion and a diameter smaller than the maximum dimension on the other side. 5. The throttle valve device according to any one of 4 above. 6. The throttle valve body is positioned with respect to the throttle body in a direction along the axis while being loaded on one side along the axis of the shaft portion. Throttle valve device.

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