JP2009180097A - Throttle device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a throttle device capable of reducing a leaked intake flow when fully closed. <P>SOLUTION: This throttle device 10 comprises: a body 12 in which a bore 17 through which an intake air flows is formed; and a valve element 14 having a shaft section 28 supported in a bearing support hole 21 formed in the body 12 rotatably through bearings 23 and a valve part 30 of butterfly valve type for opening and closing the bore 17. An annular member 50 fitted into the bore 17 side opening end of the bearing support hole 21 rotatably through an annular gap C1 is installed in the valve element 14. The annular member 50 is press-fitted to the shaft section 28 of the valve element 14, and brought into surface-contact with the axial end surface 31 of the valve section 30. The annular member 50 is formed of a press-formed part. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a throttle device that controls an intake flow rate of an internal combustion engine (engine).

A conventional example of a throttle device will be described. FIG. 11 is a cross-sectional view showing the throttle device.
As shown in FIG. 11, the throttle device 100 includes a bore forming body 101 that forms a bore 102 through which intake air flows, and a valve body 105 having a butterfly valve type valve portion 106 that opens and closes the bore 102. The valve body 105 has a shaft portion 107 that is discharged from both end faces of the valve portion 106 and is rotatably supported through a bearing 109 in a bearing support hole 103 formed in the bore forming body 101. Yes. The valve portion 106 has an axial end face 106a orthogonal to the axis. The throttle device 100 having such a configuration is described in, for example, Patent Document 1.

JP 2007-255253 A

  In the throttle device 100 (see FIG. 11), a clearance c is set between the valve portion 106 and the bearing 109 that face each other in the axial direction (left and right direction in FIG. 1) of the shaft portion 107 of the valve body 105. Has been. The gap c is set in order to reduce the sliding resistance due to the sliding contact between the bearing 109 and the valve portion 106 and improve the operability related to the opening and closing of the valve body 105. However, when the valve body 105 is fully closed during idle operation or the like (simply referred to as “when fully closed”), the clearance c leaks intake air from the upstream side to the downstream side of the valve body 105 (in FIG. 11, As a result, a straight flow path that generates an arrow y) is formed, resulting in an increase in the flow rate of intake air leakage (this is referred to as “intake leakage flow rate”).

  In Patent Document 1, the intake leakage flow rate when fully closed is reduced by providing a sealing means that elastically seals the gap between the valve portion of the valve body and the bearing. Therefore, an attempt is made to reduce the intake leakage flow rate when fully closed without relying on such sealing means.

  The problem to be solved by the present invention is to provide a throttle device capable of reducing the intake leakage flow rate when fully closed.

The above-mentioned problem can be solved by a throttle device having the gist of the configuration described in the claims.
That is, according to the throttle device described in claim 1 of the claims, the annular portion provided in the valve body is rotated through the annular clearance in the opening end portion on the bore side of the bearing support hole in the bore forming body. It is movably fitted. Therefore, the flow rate of the intake air when the valve body is fully closed (this is referred to as “intake leakage”) is bent by the annular portion of the valve body, thereby reducing the intake leakage flow rate when the valve body is fully closed. Can do.

  According to the throttle device described in claim 2 of the claims, the annular portion provided in the valve body has an annular gap in the opening end portion on the bore side of the bearing support hole of the bearing holder in the bore forming body. It is fitted so that it can rotate. Therefore, the flow path that causes intake leakage when the valve body is fully closed is bent by the annular portion of the valve body, so that the intake leakage flow rate when fully closed can be reduced.

  According to the throttle device recited in claim 3 of the claims, the annular portion is formed of an annular member attached to the valve body. Therefore, the annular portion can be formed by attaching the annular member to the valve body.

  According to the throttle device described in claim 4, the annular member is press-fitted into the shaft portion of the valve body and is in contact with the axial end surface of the valve portion. Therefore, the annular member can be easily fixed to the shaft portion of the valve body by press-fitting. At the same time, by bringing the annular member into contact with the axial end face of the valve body, the annular member can be accurately positioned with reference to the axial end face of the valve body.

  According to the throttle device recited in claim 5 of the claims, the annular member is formed with the lightening portion that opens to the outer peripheral surface of the shaft portion of the valve body. Therefore, the press-fitting load can be reduced while reducing the press-fitting area of the annular member to the shaft portion of the valve body. Moreover, since the part corresponding to the lightening part of the annular member is reduced in weight, it is possible to reduce the operating torque necessary for the rotation of the valve body.

  According to the throttle device recited in claim 6 of the claims, the annular member is formed of a press-formed product. Therefore, the manufacturing cost concerning an annular member can be reduced.

  According to the throttle device recited in claim 7 of the claims, the annular portion is formed integrally with the valve body. Accordingly, the annular portion can be easily formed in the valve body.

  According to the throttle device recited in claim 8 of the claims, the valve portion and the bore forming body having the annular portion are molded with the shaft portion and the bearing holder as an insert, and the bearing support hole of the bearing holder An annular gap between the annular portion is formed by molding shrinkage of the annular portion. Therefore, the valve part and the bore forming body having the annular part can be easily formed. Further, an annular gap between the bearing support hole of the bearing holder and the annular portion can be easily formed by utilizing the molding shrinkage of the annular portion.

  According to the throttle device recited in claim 9, the gap filling material having lubricity is provided in the annular gap between the bearing support hole and the annular portion. Therefore, by filling the annular gap between the bearing support hole and the annular portion with the gap filling material, the intake leakage flow rate through the annular gap can be reduced. Further, since the gap filling material has lubricity, it is possible to avoid a decrease in the operability of the valve body due to the provision of the gap filling material.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

[Example 1]
A first embodiment of the present invention will be described. In the present embodiment, a so-called electronically controlled throttle device that controls opening and closing of a valve body by a motor will be illustrated. For the convenience of explanation, after explaining the outline of the throttle device, the configuration of the main part will be explained. 1 is a sectional view showing the throttle device, and FIG. 2 is a sectional view taken along the line II-II in FIG.

First, an outline of the throttle device will be described. As shown in FIG. 1, the throttle device 10 includes a body main body 12 and a valve body 14.
The body body 12 is made of resin and has a bore wall portion 16 and a motor housing portion 18. The bore wall portion 16 is formed in a substantially hollow cylindrical shape, and a bore 17 through which intake air flows is formed by the hollow portion (see FIG. 2). Further, the motor housing portion 18 of the body body 12 is formed in a substantially bottomed cylindrical shape that opens to the right in FIG. An air cleaner (not shown) communicates with the upstream side (upper side in FIG. 2) of the bore wall portion 16, and an intake manifold (not shown) communicates with the downstream side (lower side in FIG. 2). It is like that. Accordingly, the intake air flowing from the air cleaner flows to the intake manifold through the bore 17. The body main body 12 corresponds to a “bore forming body” in this specification.

  As shown in FIG. 2, a pair of left and right bearing bosses 20 having a hollow cylindrical shape are integrally formed on the bore wall portion 16 in a symmetrical manner. An inner peripheral surface of the bearing boss portion 20 serves as a bearing support hole 21. A bearing 23 made of a metal annular bush is disposed in the bearing support hole 21. The bearing 23 is formed in a quadrangular cross section having both end surfaces orthogonal to the axis and inner and outer peripheral surfaces parallel to the axis. Further, the outer end portion (left end portion in FIG. 1) of the left bearing boss portion 20 is sealed with a plug 25.

  As shown in FIG. 1, the valve body 14 is formed by resin-molding a butterfly valve disk-shaped valve portion 30 with a metal throttle shaft 27 as an insert. The central portion of the valve portion 30 is formed so as to surround the central portion of the throttle shaft 27. Further, both end portions of the throttle shaft 27 protruding from the valve portion 30 are shaft portions 28. In addition, annular end surfaces (referred to as “axial end surfaces”) 31 that are orthogonal to the axis 27 </ b> L of the throttle shaft 27 are formed at both ends of the valve portion 30 in the axial direction.

  Both shaft portions 28 of the valve body 14 are rotatably supported in the bearings 23. Further, the valve portion 30 rotates integrally with the throttle shaft 27 to open and close the bore 17 of the body main body 12 and adjust the intake air flow flowing through the bore 17. A seal member 33 made of a rubber-like elastic material is provided between the right bearing boss portion 20 and the shaft portion 28 for sealing between the two.

  The right shaft portion 28 passes through the right bearing boss portion 20. A throttle gear 35 made of, for example, a resin sector gear is fixed to the tip end portion (right end portion in FIG. 1) of the shaft portion 28. Further, a back spring 37 made of a coil spring that constantly urges the throttle gear 35 in the closing direction is interposed between the throttle gear 35 and the body main body 12. A drive motor 40 made of, for example, a DC motor or the like is housed and fixed in the motor housing portion 18. Further, for example, a resin motor pinion 42 is fixed to a tip end portion (right end portion in FIG. 1) of the motor shaft 41 of the drive motor 40.

  The body 12 is provided with a resin cover 44 that closes the open end surface on the right side in FIG. A counter shaft 46 is supported between the body main body 12 and the cover body 44. For example, a counter gear 47 made of resin is rotatably supported on the counter shaft 46. The counter gear 47 has two large and small gear portions 47a and 47b having different gear diameters on the same axis. A large-diameter gear portion 47 a is engaged with the motor pinion 42, and a small-diameter gear portion 47 b is engaged with the throttle gear 35. The throttle gear 35, the motor pinion 42, and the counter gear 47 constitute a reduction gear mechanism. The reduction gear mechanism is housed in a gear housing space formed between the body main body 12 and the cover body 44. The cover body 44 is provided with a throttle position sensor 48 for detecting the opening degree of the valve body 14. The body body 12 and the cover body 44 constitute a throttle body.

  In the throttle device 10 (see FIG. 1), the drive motor 40 is controlled by a control device (not shown) such as an engine control unit of an automobile, so-called ECU, an accelerator signal or a traction control signal relating to the depression amount of the accelerator pedal. Drive control is performed based on a high-speed driving signal and an idle speed control signal. The driving force of the motor shaft 41 of the driving motor 40 is transmitted from the motor pinion 42 to the valve body 14 via the counter gear 47 and the throttle gear 35. As a result, the valve body 14 is rotated and the bore 17 is opened and closed by the valve portion 30, so that the flow rate of intake air flowing through the bore 17 is controlled.

  Next, a representative example of a method for forming the body main body 12 and the valve body 14 in the throttle device 10 will be described. Since the molding method is well known, it will be briefly described. Further, after the body body 12 and the valve body 14 are molded, the throttle device 10 is completed by assembling the plug 25, the sealing material 33, the back spring 37, the drive motor 40, the reduction gear mechanism, the cover body 44, and the like ( (See FIG. 1).

[Molding method 1]
By inserting the throttle shaft 27 into a valve molding die (mold) and injecting resin into the cavity of the valve molding die, the valve body 14 in which the valve portion 30 is integrally molded with the throttle shaft 27 is molded. Is done. Next, the body body 12 is molded by inserting the valve body 14 and the bearing 23 into the body mold (mold) and injecting resin into the cavity of the body mold.

[Molding method 2]
The body main body 12 is molded by inserting the bearing 23 in the body mold (mold) and injecting resin into the cavity of the body mold. Next, the body body 12, the throttle shaft 27 and the bearing 23 are inserted into the valve mold (mold), and the resin is injected into the cavity of the valve mold to mold the valve body 14. .

[Molding method 3]
By inserting the bearing 23 and the throttle shaft 27 in a mold (mold) and injecting resin into the valve body cavity and the body body cavity of the mold, the valve body 14 and the body body are injected. 12 is molded.

  Next, the configuration of the main part of the throttle device 10, that is, the intake leakage prevention structure when fully closed will be described. In addition, since the intake leak prevention structure including the support structure of the shaft portion 28 of the valve body 14 with respect to the bearing boss portion 20 of the body main body 12 is configured symmetrically, the right side portion thereof will be described, and the left side portion thereof will be described. The description is omitted. FIG. 3 is a cross-sectional view showing the main part.

  As shown in FIG. 3, an annular plate-shaped annular member 50 is press-fitted into the shaft portion 28 of the valve body 14. That is, the annular member 50 is fixed on the shaft portion 28 by press-fitting the shaft portion 28 into the hole 50 a of the annular member 50. The annular member 50 is made of a metal plate press-formed product. Further, the annular member 50 is brought into contact with the axial end surface 31 of the valve portion 30 in a contact surface, that is, in a surface contact manner by press-fitting the shaft portion 28. It is also possible to attach the annular member 50 to the shaft portion 28 of the throttle shaft 27 before the valve portion 30 is formed, and then form the valve portion 30 on the throttle shaft 27.

  The annular member 50 is rotatably fitted in the bearing support hole 21 of the bearing boss portion 20 via an annular gap C1. The outer diameter of the annular member 50 is set to be larger than the outer diameter of the axial end surface 31 of the valve portion 30 and smaller than the inner diameter of the bearing support hole 21 of the bearing boss portion 20. In addition, the outer diameter of the annular member 50 and the inner diameter of the bearing support hole 21 are set so that the annular gap C1 is a minute gap. The annular member 50 corresponds to the “annular portion” in this specification.

The bearing 23 is arranged at a position spaced a predetermined gap C2 from the surface of the annular member 50 opposite to the valve portion 30 side (right side in FIG. 3). With this gap C2, the sliding resistance due to the sliding contact between the bearing 23 and the annular member 50 can be reduced, and the operability related to the opening and closing of the valve body 14 can be improved.
Further, it is assumed that the axial end surface 31 of the valve portion 30 is located on substantially the same plane as the opening end surface on the bore 17 side of the bearing support hole 21 in the bearing boss portion 20. Further, the outer diameter of the axial end surface 31 is set to a diameter slightly smaller than the hole diameter of the annular member 50.

  According to the throttle device 10 described above, the annular member 50 provided in the valve body 14 is rotatably fitted in the opening end portion on the bore 17 side of the bearing support hole 21 in the body main body 12 via the annular gap C1. The Therefore, the flow path that causes suction leakage (see arrow Y in FIG. 3) from the upstream side to the downstream side of the valve body 14 when fully closed is bent by the gap C1. Therefore, the flow path is formed in a crank shape by the gap C1 and the gap C2 between the bearing 23 and the annular member 50. Thereby, compared with the case of the straight flow path of the conventional example (see FIG. 11), the intake leakage flow rate when fully closed can be reduced.

Further, the annular portion can be formed by attaching the annular member 50 to the valve body 14.
The annular member 50 is press-fitted into the shaft portion 28 of the valve body 14 and is in contact with the axial end surface 31 of the valve portion 30. Therefore, the annular member 50 can be easily fixed to the shaft portion 28 of the valve body 14 by press fitting. At the same time, by bringing the annular member 50 into contact with the axial end face 31 of the valve body 14, the annular member 50 can be accurately positioned with reference to the axial end face 31 of the valve body 14.
The annular member 50 is made of a press-formed product. Therefore, the manufacturing cost concerning the annular member 50 can be reduced.

[Example 2]
A second embodiment will be described. Since the present embodiment is obtained by changing a part of the first embodiment, the changed portion will be described, and redundant description will be omitted. Also, in the following embodiments, the changed parts will be described, and redundant description will be omitted. FIG. 4 is a cross-sectional view showing the main part.
In this embodiment, as shown in FIG. 4, a grease-like gap filling material having lubricity is provided in the annular gap C1 between the annular member 50 and the bearing support hole 21 of the bearing boss portion 20 in the first embodiment. 54 is applied. As the gap filling material 54, for example, Moricoat (registered trademark of Toray Dow Corning Co., Ltd.) can be used.

  According to the present embodiment, the annular gap C1 between the bearing support hole 21 of the bearing boss portion 20 and the annular member 50 is filled with the gap filling material 54, thereby reducing the intake leakage flow rate through the annular gap C1. be able to. Further, since the gap filling material 54 has lubricity, it is possible to avoid a decrease in the operability of the valve body 14. The gap filling material 54 may be provided in at least the downstream half or the upstream half of the annular gap C1.

[Example 3]
A third embodiment will be described. In the present embodiment, a part of the first embodiment is modified. FIG. 5 is a sectional view showing the main part.
In the present embodiment, as shown in FIG. 5, a metal cylindrical bearing holder 56 is provided in the bearing boss portion 20 in the first embodiment. The bearing 23 is provided with the inner peripheral surface of the bearing holder 56 as a bearing support hole 57. Further, instead of the annular member 50 in the first embodiment, an annular portion 60 having the same outer shape as the outer shape of the annular member 50 is provided on the axial end surface side (right side in FIG. 5) of the valve portion 30 of the valve body 14. 30 is formed by integral molding. The annular portion 60 is fitted in the bearing support hole 57 of the bearing holder 56 so as to be rotatable via an annular gap C1.

  In the present embodiment, the body body 12 and the valve body 14 are molded based on the molding method 3. That is, by inserting the bearing 23, the throttle shaft 27, and the bearing holder 56 in the mold (mold), and injecting the resin into the valve body cavity and the body body cavity of the mold, The valve body 14 and the body main body 12 are molded. Thereafter, an annular gap C <b> 1 is formed between the annular portion 60 of the valve portion 30 and the bearing holder 56 by molding shrinkage of the annular portion 60.

  According to the present embodiment, the annular portion 60 provided in the valve body 14 is rotatably fitted in the opening end portion on the bore 17 side of the bearing support hole 57 of the bearing holder 56 in the body main body 12 via the annular gap C1. Combined. Therefore, the flow path that causes suction leakage (see arrow Y in FIG. 3) from the upstream side to the downstream side of the valve body 14 when fully closed is bent by the gap C1. For this reason, the flow path is formed in a crank shape by the gap C <b> 1 and the gap C <b> 2 between the bearing 23 and the annular portion 60. Thereby, compared with the case of the straight flow path of the conventional example (see FIG. 11), the intake leakage flow rate when fully closed can be reduced.

  Further, the annular portion 60 is formed on the valve body 14 by integral molding. Therefore, the annular portion 60 can be easily formed in the valve body 14.

  Further, the valve portion 30 having the annular portion 60 and the body main body 12 are resin-molded using the shaft portion 28 and the bearing holder 56 as inserts, and an annular gap C1 between the bearing support hole 57 of the bearing holder 56 and the annular portion 60 is formed. Is formed by molding shrinkage of the annular portion 60. Therefore, the valve part 30 and the body main body 12 having the annular part 60 can be easily formed. Further, the annular clearance C <b> 1 between the bearing support hole 57 of the bearing holder 56 and the annular part 60 can be easily formed by utilizing the molding shrinkage of the annular part 60.

  In addition, it replaces with the valve body 14 which integrally molded the annular part 60 of the present Example, and the valve body 14 which provided the annular member 50 in the said Example 1 can also be used.

[Example 4]
Example 4 will be described. In the present embodiment, a part of the first embodiment is modified. FIG. 6 is a cross-sectional view showing the main part.
In the present embodiment, as shown in FIG. 6, the outer peripheral surface of the annular member 50 is an uneven surface 50b. As the uneven surface 50b, shapes such as a knurled shape, a male screw shape, and a pulley shape are conceivable.
According to the present embodiment, the wall surface resistance of the flow of intake leakage is increased by the uneven surface 50b on the outer peripheral surface of the annular member 50, whereby the intake leakage flow rate when fully closed can be reduced.

[Example 5]
Example 5 will be described. In the present embodiment, a part of the first embodiment is modified. FIG. 7 is a cross-sectional view showing the main part.
In the present embodiment, as shown in FIG. 7, chamfered tapered surfaces 50 c are formed at both opening ends of the inner peripheral surface of the hole 50 a of the annular member 50. As a result, a lightening portion 62 that opens to the outer peripheral surface of the shaft portion 28 of the valve body 14 is formed at both opening end portions of the inner peripheral surface of the hole 50 a of the annular member 50.
According to the present embodiment, by forming the thinned portion 62 in the annular member 50, the press-fitting load can be reduced while reducing the press-fitting area of the annular member 50 with respect to the shaft portion 28 of the valve body 14. As a result, the impact on the axial end surface 31 of the valve portion 30 when the annular member 50 is press-fitted can be reduced, and cracking of the valve portion 30 due to the impact can be prevented or reduced. Further, since the portion corresponding to the lightening portion 62 of the annular member 50 is reduced in weight, it is possible to reduce the operating torque necessary for the rotation of the valve body 14. The tapered surface 50c is not limited to those formed at both opening end portions of the inner peripheral surface of the hole 50a of the annular member 50, and may be formed at any one opening end portion.

[Example 6]
Example 6 will be described. In the present embodiment, the present embodiment is obtained by changing a part of the first embodiment. FIG. 8 is a cross-sectional view showing the main part.
In the present embodiment, as shown in FIG. 8, a cylindrical support shaft portion 64 that protrudes from the inner peripheral portion of the axial end surface 31 of the valve portion 30 and surrounds the shaft portion 28 is integrally formed. The portion 64, that is, the resin portion is press-fitted into the hole 50 a of the annular member 50.

[Example 7]
Example 7 will be described. In the present embodiment, a part of the first embodiment is modified. FIG. 9 is a cross-sectional view showing the main part.
In the present embodiment, as shown in FIG. 9, a rectangular cross section is formed on the inner peripheral surface of the hole 50 a of the annular member 50, opening on the end surface 31 of the valve portion 30 and facing the outer peripheral surface of the shaft portion 28 of the valve body 14. In this case, the lightening portion 66 is formed.
According to the present embodiment, by forming the thinned portion 66 in the annular member 50, it is possible to reduce the press-fit area of the annular member 50 with respect to the shaft portion 28 of the valve body 14 and reduce the press-fit load. As a result, the impact on the axial end surface 31 of the valve portion 30 when the annular member 50 is press-fitted can be reduced, and cracking of the valve portion 30 due to the impact can be prevented or reduced. Further, since the portion corresponding to the lightening portion 66 of the annular member 50 is reduced in weight, it is possible to reduce the operating torque necessary for the rotation of the valve body 14.

[Example 8]
Example 8 will be described. In this embodiment, a part of the embodiment 7 is changed. FIG. 10 is a cross-sectional view showing the main part.
In this embodiment, as shown in FIG. 10, a cylindrical guide tube portion 68 that protrudes toward the end surface 31 of the valve portion 30 and extends the axial length of the hole 50 a is provided on the inner peripheral portion of the annular member 50. Is.

  The present invention is not limited to the above-described embodiments, and modifications can be made without departing from the gist of the present invention. For example, the body body 12 is not limited to resin, but can be made of metal. Moreover, in the said Example, although the metal throttle shaft 27 and the resin valve | bulb part 30 were integrated, the valve body 14 was comprised, instead of this, the shaft part 28 and the valve | bulb part 30 are integrated with resin. Thus, a single-part valve body 14 can be obtained. Alternatively, the valve body 14 can be configured by attaching a metal or resin valve portion 30 to a metal or resin throttle shaft 27 with a screw or the like. Further, the annular member 50 is not limited to metal but can be made of resin. Further, the annular member 50 may be fixed to the valve body 14 by press fitting, or may be fixed by adhesion, welding or the like. The annular portion 60 is not limited to being formed integrally with the valve portion 30 and may be integrally formed with the shaft portion 28.

It is sectional drawing which shows the throttle apparatus which concerns on Example 1 of this invention. It is the II-II sectional view taken on the line of FIG. It is sectional drawing which shows the principal part. FIG. 6 is a cross-sectional view showing a main part according to a second embodiment. FIG. 6 is a cross-sectional view illustrating a main part according to a third embodiment. FIG. 10 is a cross-sectional view showing a main part according to a fourth embodiment. FIG. 10 is a cross-sectional view showing a main part according to a fifth embodiment. FIG. 10 is a cross-sectional view showing the main parts according to Example 6. FIG. 10 is a cross-sectional view showing the main parts according to Example 7. FIG. 10 is a cross-sectional view showing the main parts according to Example 8. It is sectional drawing which shows the throttle apparatus which concerns on a prior art example.

Explanation of symbols

10 Throttle device 12 Body body (bore forming body)
14 Valve body 17 Bore 21 Bearing support hole 23 Bearing 28 Shaft part 30 Valve part 31 Axial end face 50 Annular member (annular part)
54 Gap Filling Material 56 Bearing Holder 57 Bearing Support Hole 60 Annular Portion 62 Thinned Portion 66 Thinned Portion C1 Clearance C2 Clearance

Claims (9)

A bore forming body forming a bore through which intake air flows; and
A throttle device comprising: a shaft portion rotatably supported via a bearing in a bearing support hole formed in the bore forming body; and a valve body having a butterfly valve type valve portion for opening and closing the bore. ,
A throttle device, wherein the valve body is provided with an annular portion that is rotatably fitted through an annular gap in an opening end portion on the bore side of the bearing support hole. A bore forming body forming a bore through which intake air flows; and
A cylindrical bearing holder provided in the bore forming body and forming a bearing support hole;
A throttle device comprising: a shaft portion rotatably supported through a bearing in a bearing support hole of the bearing holder; and a valve body having a butterfly valve type valve portion for opening and closing the bore,
A throttle device, wherein the valve body is provided with an annular portion that is rotatably fitted through an annular gap in an opening end portion on a bore side of the bearing holder. The throttle device according to claim 1 or 2,
The throttle device according to claim 1, wherein the annular portion includes an annular member attached to the valve body. The throttle device according to claim 3,
The throttle device, wherein the annular member is press-fitted into a shaft portion of the valve body and is in contact with an axial end surface of the valve portion. The throttle device according to claim 4, wherein
The throttle device according to claim 1, wherein a hollow portion that is open on an outer peripheral surface of the shaft portion of the valve body is formed in the annular member. The throttle device according to any one of claims 3 to 5,
A throttle device characterized in that the annular member is made of a press-molded product. The throttle device according to claim 1 or 2,
The throttle device according to claim 1, wherein the annular portion is formed integrally with the valve body. The throttle device according to claim 2,
Using the shaft part and the bearing holder as an insert, the valve part and the bore forming body having the annular part are resin-molded,
The throttle device, wherein the annular gap between the bearing support hole of the bearing holder and the annular portion is formed by molding shrinkage of the annular portion. The throttle device according to any one of claims 1 to 8,
A throttle device, wherein a gap filling material having lubricity is provided in the annular gap between the bearing support hole and the annular portion.

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