JPH11193726A - Seal structure of throttle device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure a sufficient amount of sealing surface with increase of the flow-through resistance being prevented despite the shrinkage of the molded passage. SOLUTION: A passage having an intake passage is formed in a mold. Bosses are formed at least one side of the intake passage on a diameter thereof. A valve shaft having an axis rectangular to the diameter is rotatably supported by the passage. A pair of circular sealing surfaces are formed to contact the outer periphery of a butterfly valve 12 fixed to the valve shaft at both sides of the valve shaft respectively when the butterfly valve is fully closed. The sealing structure of a throttle device is formed on the inner surface of the intake passage such that the width of sealing surfaces 161 , 162 corresponding to bosses 10a1 , 10b1 of the passage 101 is the larger as they are parted from the valve shaft 13 and becomes the largest when the bosses are farthest from the valve shaft 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a butterfly valve which is rotatably supported on a passage forming body which has an intake passage and which is formed by molding, and which is fixed to the valve shaft. The present invention relates to a seal structure of a throttle device in which a pair of seal surfaces that contact substantially half of the outer periphery of a butterfly valve on both sides of the valve shaft when closed are formed on the inner surface of an intake passage.

[0002]

2. Description of the Related Art Conventionally, such a sealing structure has been disclosed in, for example, Japanese Patent Application Laid-Open Nos. 5-171960 and 7-2796.
No. 98 has already been known.

[0003]

By the way, in such a throttle device, when the butterfly valve is fully closed, an idle adjustment screw for adjusting an air flow rate in a bypass passage that bypasses the butterfly valve, and a hot water for preventing icing. A hot water riser or the like for guiding (engine cooling water) is provided in the passage forming body, and the idle adjustment screw, the hot water riser, and the like are provided on at least one of the intake passages on one diameter line of the intake passage orthogonal to the axis of the valve shaft. Is generally provided in the passage forming body on the side, and the passage forming body is formed such that the thickness of the portion where the idle adjust screw, the hot water riser, etc. are disposed is larger than the thickness of the other portions. Have been. In addition, since the passage forming body is formed by molding with a metal casting mold or by injection molding of a synthetic resin, shrinkage sink after molding becomes the largest in the direction along the one diameter line.

However, in the above-mentioned conventional device, when the butterfly valve is fully closed, a pair of sealing surfaces which contact on both sides of the valve shaft substantially every half of the outer periphery of the butterfly valve are evenly distributed along the circumferential direction of the intake passage. The contraction sinkage, which is the largest in the direction perpendicular to the axis of the valve shaft, allows the contact area of the sealing surface to the butterfly valve in the direction perpendicular to the axis of the valve shaft to be sufficient. It may not be possible to secure. Further, if the width of the sealing surface is determined in consideration of the shrinkage sink, the sealing area of the sealing surface becomes larger than necessary on the side close to the valve shaft, and the flow resistance at the time of opening the butterfly valve increases. .

[0005] The present invention has been made in view of the above circumstances, and it is possible to secure a sufficient sealing area while avoiding an increase in flow resistance, despite shrinkage of a passage forming body to be molded. It is an object of the present invention to provide a seal structure for a throttle device.

[0006]

In order to achieve the above-mentioned object, the present invention relates to a passage forming body having an intake passage, which is formed by molding at least one of the intake passages on one diameter line of the intake passage. The thick portion located on the side is formed so as to be thicker than the portion other than the thick portion along the circumferential direction of the intake passage, and has an axis orthogonal to the one diameter line to form the intake passage. A transverse valve shaft is rotatably supported by the passage forming body,
When the butterfly valve fixed to the valve shaft is fully closed, a pair of sealing surfaces formed in an arc shape so as to come into contact with the outer periphery of the butterfly valve on both sides of the valve shaft, respectively, are formed on the inner surface of the intake passage. In the seal structure of the device, the width of the seal surface of the two seal surfaces on the side corresponding to the thick portion of the passage forming body is maximized at a position farthest from the valve shaft, but becomes closer to the valve shaft. It is characterized in that it is formed to be small.

According to this configuration, the width of the sealing surface along the radial direction of the intake passage is maximum at a position farthest from the valve shaft, and decreases as the position approaches the valve shaft. Although the shrinkage shrinkage is largest in the portion corresponding to the thick portion, that is, in the direction along one diameter line of the intake passage perpendicular to the axis of the valve shaft, the sealing surface in the direction along the one diameter line A sufficient contact area with the butterfly valve can be ensured, and the sealing area of the sealing surface on the side close to the valve shaft does not become unnecessarily large, thereby increasing the flow resistance when the butterfly valve is opened. Can be prevented.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described based on embodiments of the present invention shown in the accompanying drawings.

1 and 2 show a first embodiment of the present invention. FIG. 1 is a longitudinal sectional view of a throttle device, and FIG.
FIG. 2 is a sectional view taken along line 2-2 of FIG. 1.

[0010] The throttle body 10 ₁ of the passage defining member is formed by injection molding of synthetic resin, the intake passage 11 ₁ which extends in a straight line is provided a cross-sectional shape as a circular, of the intake passage 11 ₁ valve shaft 13 traversing the intake passage 11 ₁ has an axis perpendicular to one diameter line L is rotatably supported by the throttle body 10 _1, the intake passage 11
₁ of the flow area butterfly valve for regulating the 12, for example, is fixed to the valve shaft 13 by a pair of screw members 14, 14.

[0011] The throttle body 10 ₁ has a first raised portion 15 ₁ corresponding to approximately half of the butterfly valve 12 on one side of the valve shaft 13, corresponding to approximately half of the butterfly valve 12 in the other side of the valve shaft 13 a second raised portion 15 ₂ is provided integrally so as to bulge radially inwardly from the inner surface of the intake passage 11 _1, on the upstream side along the flow direction 17 of the air in the intake passage 11 within ₁ is formed on the first raised portion 15 ₁ as possible that the first sealing surface 16 ₁ of the arc-shaped contacts the substantially half of the outer circumference of the butterfly valve 12 fully closed facing and downstream along the flow direction 17 The facing second arc-shaped second sealing surface 16 ₂
There are formed _two second projections 15 as possible to contact the substantially half of the outer circumference of the butterfly valve 12 fully closed.

The intake passage 11 ₁ on the one diameter line L
The throttle body 10 ₁ at one side of the butterfly valve 1
When the valve 2 is fully closed, a bypass passage 18 that bypasses the butterfly valve 12 is provided, and an idle adjust screw 19 for adjusting the flow rate of air flowing through the bypass passage 18 is screwed forward and backward freely. The throttle body 10 ₁ in the intake passage 11 ₁ in the other side on the one diameter line L, the hot water riser (not shown) is provided. By this arrangement of the bypass passage 18 and the idle adjust screw 19 and the hot water riser, the throttle body 10 _1, the thick portion 1 positioned on both sides of the intake passage 11 ₁ in the intake passage 11 ₁ on one diameter line L
0a _1, 10b ₁ is formed the thickness as large than the circumferential along said direction thick portion 10a _1, 10b ₁ other than the portion of the intake passage 11 _1.

The first and second raised portions 15 ₁ , 15 ₂
Of ridges, the intake passage 11 ₁ in the circumferential direction the valve shaft 13
Is largest at a position furthest away from the valve shaft 13 and becomes smaller as it approaches the valve shaft 13.
_1st and 2nd sealing surfaces 16 ₁ , 1 along the radial direction
6 _second width is maximized at the position farthest from the valve shaft 13 will be less toward the valve stem 13.

[0014] Furthermore, the first projections 15 _1, downstream of the portion along the first sealing surface 16 _first flow direction 17 than is formed into smoothly curved shape, the second raised portion 15 _2, a second
The seal surface 16 ₂ parts of the upstream side along the flow direction 17 is formed on the smooth curved shape. By forming the first and second raised portions 15 ₁ and 15 _{2 in} this manner, the air flowing through the intake passage 11 ₁ when the butterfly valve 12 is opened flows downstream of the raised portions 15 ₁ and 15 ₂ . Can be suppressed as much as possible. Especially when the throttle body 10 ₁ is made of a synthetic resin,
Although the airflow noise caused by the airflow turbulence passes through the synthetic resin, the generation of the airflow noise can be effectively reduced by suppressing the airflow turbulence as described above.

[0015] Next, to explain the action of this first embodiment, both the sealing surface along the radial direction of the intake passage 11 ₁ 16
_1, 16 ₂ of the width is maximum at the position farthest from the valve axis 13, is set to be smaller as closer to the valve shaft 13. Therefore, the shrinkage sink generated after molding the throttle body 10 ₁ is greatest in the direction corresponding to the thick portions 10a ₁ and 10b ₁ , that is, along the one diameter line L of the intake passage 11 ₁ orthogonal to the axis of the valve shaft 13. Despite becomes, the can be sufficiently ensured the contact area to the butterfly valve 12 of the two sealing surfaces 16 _1, 16 ₂ in the direction along one diameter line L, also both on the side close to the valve shaft 13 Since the sealing area of the sealing surfaces 16 ₁ and 16 ₂ does not become unnecessarily large, it is possible to prevent the flow resistance from increasing when the butterfly valve 12 is open.

In addition, since a sufficient sealing area can be ensured by the two sealing surfaces 16 ₁ and 16 ₂ , when the butterfly valve 12 is fully closed, the butterfly valve 12 is
It is possible to set a relatively small force for pressing on 6 ₁ and 16 ₂ . If the return spring biases the butterfly valve 12 is fully opened side (not shown) is provided between the valve shaft 13 and the throttle body 10 ₁ is therefore the throttle body 10 ₁ is made of a synthetic resin Despite, it becomes unnecessary to reinforce the throttle body 10 ₁ at a portion where the return spring is coupled.

The first and second sealing surfaces 16 ₁ , 16 ₁
The first and second projections 15 _1, 15 to form the ₂
Because ₂ is provided in the throttle body 10 ₁ so as to bulge from the inner surface of the intake passage 11 _1, the stiffness reduction of the throttle body 10 ₁ by the bypass passage 18 and the hot water riser provided in the throttle body 10 ₁ both it can be compensated by the projections 15 _1, 15 _2.

3 and 4 show a second embodiment of the present invention. FIG. 3 is a vertical sectional view of a throttle device, and FIG.
FIG. 4 is a sectional view taken along line 4-4 of FIG.

[0019] The throttle body 10 _second intake passage 11 ₂ provided in the first passage portion 11a of circular cross section which is disposed upstream along the flow direction 17 and extends in a straight line
And a second passage portion 11b having a circular cross section and extending in a straight line and arranged on the downstream side along the flow direction 17;
The two passage portions 11a, 11b are eccentrically connected to each other on one diameter line L, and are connected to each other.
Valve shaft 13 having an axis the perpendicular as one diameter line L in 1b connecting portion of, is rotatably supported by the throttle body 10 ₂ so as to cross the intake passage 11 _2, the flow of the intake passage 11 ₂ A butterfly valve 12 for adjusting the area is fixed to a valve shaft 13.

The intake passage 11 ₂ on the one diameter line L
The throttle body 10 ₂ in one side of the bypass passage 1
8 and idle adjustment screw 19 is arranged, the throttle body 10 ₂ in the other side of the intake passage 11 ₂ in on one diameter line L is hot water riser (not shown) is provided, the throttle body 10 _2, intake thick portion 10a _2, 10b ₂ located on both sides of the intake passage 11 ₂ at passage 11 ₂ on one diameter line L, the intake passage 11 ₂ in the circumferential along said direction thick portion 10a _2, 10b ₂ other than It is formed to have a greater thickness than the portion.

Based on the fact that the first and second passage portions 11a and 11b are eccentric with respect to each other, the intake passage 11 ₂ in the continuous portion of the first and second passage portions 11a and 11b is provided.
The inner surface includes a first sealing surface 16 ₁ arcuate facing the upstream side periphery so as to contact the substantially half of the along the flow direction 17 of the fully closed butterfly valve 12, fully closed butterfly valve 12 In the flow direction 17 so as to contact substantially half of the outer circumference of the
And ₂ second sealing surface 16 arcuate facing downstream along the is formed, the first and second sealing surfaces 16 _1, 16 ₂ in the width along the radial direction of the intake passage 11 _2, the valve shaft 13 At the position furthest away from the valve shaft, but decreases as the position approaches the valve shaft 13.

Further air flowing through the intake passage 11 within ₂ during the opening of the butterfly valve 12, the first and second passage portions 1
In order to minimize the disturbance caused by the eccentric arrangement of the first sealing surface 16 ₁ and the second passage portion 1,
1b is formed in a smoothly curved shape,
Connecting portions of the sealing surface 16 ₂ and the first passage portion 11a is also formed smoothly curved shape.

According to the second embodiment, the same effects as those of the first embodiment can be obtained.

Although the embodiments of the present invention have been described in detail, the present invention is not limited to the above embodiments, and various design changes can be made without departing from the present invention described in the appended claims. It is possible to do.

For example, in the above-described embodiment, thick portions are formed in the throttle body on both sides of the intake passage on one diameter line of the intake passage, and the width of both seal surfaces becomes maximum at the position farthest from the valve shaft. Although formed so as to become smaller as approaching the valve shaft, the present invention is also applicable to a structure in which a thick portion is formed in the throttle body on one side of the intake passage on one diameter line of the intake passage. In such a case, the width of the seal surface corresponding to the thick portion of the two seal surfaces may be formed so as to be maximum at a position farthest from the valve shaft but to decrease as the position approaches the valve shaft.

In the above embodiment, the case where the throttle body as the passage forming body is made of a synthetic resin has been described. However, the present invention is also applicable to the case where the throttle body is made of metal by casting. It is. Further, the present invention is applicable to a case where the passage forming body is a carburetor body of the carburetor.

[0027]

As described above, according to the present invention, the shrinkage sink formed after the passage forming body is formed is along the portion corresponding to the thick portion, that is, along one diameter line of the intake passage orthogonal to the axis of the valve shaft. Despite being the largest in the direction, the contact area of the seal surface with the butterfly valve in the direction along the one diameter line can be sufficiently ensured, and the seal area of the seal surface on the side close to the valve shaft is small. Since it does not become larger than necessary, it is possible to prevent the flow resistance when the butterfly valve is opened from increasing.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a throttle device according to a first embodiment.

FIG. 2 is a sectional view taken along line 2-2 of FIG.

FIG. 3 is a longitudinal sectional view of a throttle device according to a second embodiment.

FIG. 4 is a sectional view taken along line 4-4 of FIG. 3;

[Explanation of symbols]

10 ₁ , 10 ₂ ··· Throttle body 10a ₁ , 10a ₂ , 10b ₁ , 10b ₂ ··· Thick portion 11 ₁ · 11 ₂ ··· Intake passage 12 ··· Butterfly valve 13 · ..Valve shafts 16 ₁ and 16 ₂ ... Seal surfaces L...

Claims (1)

[Claims] An intake passage (11)₁, 11_Two) Has a mold
The passage forming body (10₁, 10_Two), The intake
Passage (11₁, 11_Two) On one diameter line (L).
Road (11₁, 11_Two) At least on one side
Meat (10a ₁, 10b₁; 10a_Two, 10b_Two)But,
The intake passage (11)₁, 11_TwoA) along the circumferential direction
Thick part (10a₁, 10b₁; 10a_Two, 10b_Two)
The one-diameter line is formed with a greater thickness than the outer part.
(L) and an intake passage (11₁, 11
_Two) Crossing the passage forming body (10).₁,
10_Two) Is rotatably supported on the valve shaft (13).
When the butterfly valve (12) is completely closed, the valve shaft (1) is closed.
3) Contact the outer circumference of the butterfly valve (12) on both sides
A pair of sealing surfaces (16₁,
16_Two) Is the intake passage (11)₁, 11_TwoInside)
In the formed throttle structure of the throttle device,
Both seal surfaces (16₁, 16_Two), The passage forming body (10
₁, 10_Two) Of the thick portion (10a₁, 10b₁; 10
a_Two, 10b_Two) Corresponding to the sealing surface (16)₁, 1
6_Two) At the position farthest from the valve shaft (13)
Maximum but smaller as approaching the valve shaft (13)
Throttle device characterized by being formed
Seal structure.