JP4267561B2 - Throttle body - Google Patents

Description

The present invention forms part of an intake passage of an internal combustion engine (engine), about the throttle body to control the amount of intake air.

For example, in a manufacturing method of a throttle body (also referred to as an air flow rate control device) that includes a body main body in which an intake passage is formed and a valve body that is rotatably provided in the body main body and opens and closes the intake passage. A manufacturing method has been proposed in which a valve body is resin-molded by inserting a main body (see, for example, Patent Document 1).
Japanese Patent Laying-Open No. 2002-256898 (see claim 5, embodiment 4, FIGS. 5 and 6)

  In Patent Document 1, since the valve body is resin-molded by inserting the body body, a body insert mold (mold) that matches the dimensions of the body body, a so-called valve mold is required. However, since such a valve molding die must correspond to a complicated shape of the main body of the body, there is a problem that the mold structure is complicated and the cost is inevitably increased.

The problem to be solved by the present invention is to provide a throttle body capable of reducing the cost.

The problem can be more resolved the throttle body to subject matter the configuration described in the appended claims.
That is, according to the throttle body described in claim 1, the body body is resin-molded by inserting the resin-molded valve body in the fully closed position . Therefore, a mold having a complicated mold structure for inserting the body body is not required, and the mold structure of the mold for resin molding of the body body is simplified, thereby reducing the cost.

Further, the outer peripheral end surface of the valve body is tapered so that the outer diameter gradually decreases from the surface located on the opening side of the valve body toward the surface located on the closing side, and corresponds to the free end portion of the valve body. Formed by a tapered curved surface in which the taper angle gradually decreases from the position to the both bearing parts side, and by inserting the valve body and resin-molding the body body, the outer peripheral end surface of the valve body A valve seal surface is formed on the inner wall surface of the body.
Therefore, even when the fully closed position of the valve body is shifted in the opening direction in accordance with the molding shrinkage of the body (corresponding to “shrinkage” in the present specification), the body formed by the outer peripheral end surface of the valve body is used. The outer peripheral end surface of the valve body (specifically, the outer peripheral edge of the surface located on the closing side) abuts the valve sealing surface of the main body without swaying in the circumferential direction, so that the valve sealing surface of the body main body and the valve It is possible to seal between the outer peripheral end surfaces of the body . Thus, it is possible to reduce or avoid the malfunction of the valve body by-out Kuitsu of the valve body at fully closed. At the same time, by sealing the outer peripheral end surface of the valve body in the circumferential direction with respect to the valve seal surface of the body body, it is possible to prevent or reduce an increase in the amount of air leakage due to the generation of a gap between them.

According to the throttle body described in claim 2 , the curved portion is formed at least on the large-diameter side portion of the outer peripheral end surface of the valve body.
With this configuration, the intake flow rate per unit throttle opening in the low opening range of the valve body can be reduced, so that the accuracy of the decomposition of the intake flow rate relative to the throttle opening by the valve body is improved, and the throttle body is improved. The low opening degree characteristic can be improved. In addition, the “curved portion” referred to in this specification includes a shape that approximates an arc such as an involute, a quadratic curve, and a cubic curve, in addition to an R-shaped portion and an elliptical portion.

According to the throttle body of the present invention, a mold having a complicated mold structure for inserting the body of the body is unnecessary, and the mold structure of the mold for resin molding of the body of the body can be simplified and the cost can be reduced. . Furthermore, it is possible to prevent malfunction of the valve body and increase in the amount of air leakage when fully closed.

Hereinafter, the best mode for carrying out the present invention will be described with reference to the following examples.
[Example 1]

A first embodiment of the present invention will be described with reference to the drawings. In the present embodiment, a throttle body used in a throttle control device will be exemplified. First, the outline of the throttle control device will be described. As shown in FIG. 1, an electronically controlled throttle control device 1 includes a throttle body 2 that forms the main body.
As shown in FIG. 2, the throttle body 2 includes a resin body body 3 and a resin valve body 14.
The body 3 has a bore wall 4 and a motor housing 6 integrally. A substantially hollow cylindrical intake passage 7 penetrating in the front and back direction in FIG. 2 is formed in the bore wall 4 (see FIGS. 3 and 4). Although not shown, an air cleaner is connected to the upstream side of the bore wall portion 4, and an intake manifold is connected to the downstream side of the bore wall portion 4.

As shown in FIGS. 2 and 4, a metal throttle shaft 8 is disposed in the bore wall 4 so as to cross the intake passage 7 in the radial direction. One end portion (left end portion in FIG. 2) 8 a of the throttle shaft 8 is rotatably supported via a metal bearing 10 in the left bearing portion 9 formed integrally with the bore wall portion 4. The other end portion (the right end portion in FIG. 2) 8b of the throttle shaft 8 is rotatably supported via a metal bearing 12 with respect to the right bearing portion 11 formed integrally with the bore wall portion 4. Yes. The right bearing portion 11 is fitted with a plug 16 that seals the opening end face.
A resin valve body 14 capable of opening and closing the intake passage 7 by rotation is molded on the throttle shaft 8 (see FIG. 3). The valve body 14 controls the amount of intake air flowing through the intake passage 7 by opening and closing the intake passage 7 by driving a motor 20 (described later).

As shown in FIG. 2, the left end 8 a of the throttle shaft 8 passes through the left metal bearing 10. A throttle gear 18 made of a resin sector gear, for example, is integrally provided at the end 8a of the throttle shaft 8.
A back spring 19 located on substantially the same axis is interposed between the body main body 3 and the throttle gear 18. The back spring 19 always urges the throttle gear 18 in the closing direction of the valve body 14.

The motor housing 6 of the body 3 is formed in a substantially bottomed cylindrical shape that is parallel to the rotation axis L of the throttle shaft 8 and opens to the left in FIG. A motor 20 made of, for example, a DC motor is disposed in the motor housing 6. A mounting flange 22 provided in a motor casing 21 that forms an outer shell of the motor 20 is fixed to the body main body 3 with a screw 23.
Further, a resin motor pinion 26, for example, is integrally provided on the output rotation shaft 24 of the motor 20.

A countershaft 27 parallel to the rotation axis L of the throttle shaft 8 is provided between the body body 3 and a cover 30 (described later). For example, a counter gear 28 made of resin is rotatably supported on the counter shaft 27. The counter gear 28 has a large-diameter gear portion 28a and a small-diameter gear portion 28b having different gear diameters. A large-diameter gear portion 28 a is engaged with the motor pinion 26, and a small-diameter gear portion 28 b is engaged with the throttle gear 18.
The throttle gear 18, the motor pinion 26, and the counter gear 28 constitute a reduction gear mechanism 29.

On one side surface (the left side surface in FIG. 2) of the body 3, for example, a resin cover 30 for covering the reduction gear mechanism 29 and the like is provided with coupling means such as snap-fit means, clip means, and screw fastening means. Are connected through. An O-ring (O-ring) 31 is interposed between the body main body 3 and the cover 30 to keep the airtight inside.
As shown in FIG. 1, the cover 30 is provided with a connector portion 33. An external connector (not shown) can be connected to the connector portion 33. Although not shown, a connector connected to the motor 20 and a terminal connected to a rotation angle sensor 38 (described later) are disposed in the connector 33.

  In FIG. 1, the motor 20 responds to an accelerator signal, a traction control signal, a constant speed running signal, and an idle speed control signal related to the amount of depression of an accelerator pedal by a control means (not shown) such as an engine control unit of an automobile, so-called ECU. Drive control. The driving force of the output rotating shaft 24 of the motor 20 is transmitted from the motor pinion 26 to the throttle shaft 8 via the counter gear 28 and the throttle gear 18. Thereby, as a result of the valve body 14 being rotated, the intake passage 7 is opened and closed.

As shown in FIG. 2, the throttle gear 18 is integrally provided with a yoke 35 made of a ring-shaped magnetic material located on the same axis as the rotation axis L of the throttle shaft 8. A pair of magnets 36 and 37 for generating a magnetic field are integrated on the inner peripheral surface of the yoke 35. Both magnets 36 and 37 are made of, for example, a ferrite magnet, and are magnetized in parallel so that the magnetic lines of force generated between them, that is, the magnetic field are parallel to each other, and generate a substantially parallel magnetic field in the space in the yoke 35.
A rotation angle sensor 38 including a sensor IC 39 incorporating a magnetoresistive element is disposed on the inner side surface of the cover 30. The rotation angle sensor 38 is disposed at a position on the rotation axis L of the throttle shaft 8 with a predetermined interval between the magnets 36 and 37. The sensor IC 39 of the rotation angle sensor 38 calculates the output from the magnetoresistive element and outputs an output signal corresponding to the direction of the magnetic field to the control means such as the ECU, without depending on the strength of the magnetic field, The direction of the magnetic field can be detected.

In the throttle control device 1 (see FIG. 2), when the engine is started, the motor 20 is driven and controlled by a control means such as an ECU. As a result, as described above, the valve body 14 is opened and closed via the reduction gear mechanism 29, and as a result, the amount of intake air flowing through the intake passage 7 of the body body 3 is controlled. When the yoke 35 and the magnets 36 and 37 rotate together with the throttle gear 18 as the throttle shaft 8 rotates, the direction of the magnetic field that intersects the sensor IC 39 of the rotation angle sensor 38 changes according to the rotation angle. As a result, the output signal of the sensor IC 39 changes. In the control means (not shown) such as the ECU that outputs the output signal of the sensor IC 39, the rotation angle of the throttle shaft 8, that is, the opening degree of the valve body 14 is calculated based on the output signal of the sensor IC 39.
Further, a control means such as an ECU includes a throttle opening detected by the direction of the magnetic field output from the sensor IC 39 of the rotation angle sensor 38 and detected as the magnetic physical quantity of the pair of magnets 36 and 37, and a vehicle speed sensor (not shown). Fuel injection control and correction control of the opening degree of the valve body 14 based on the vehicle speed detected by the engine, the engine speed by the crank angle sensor, and detection signals from sensors such as an accelerator pedal sensor, an O2 sensor, and an air flow meter. Controls so-called control parameters such as automatic transmission shift control.

Next, the main part of the throttle body 2 will be described.
As shown in FIG. 3, the valve body 14 is resin-molded to form an outer peripheral end surface 14 a that contacts a valve seal surface 5 (described later) of the body main body 3.
The body 3 is resin-molded with the valve body 14 inserted. A valve seal surface 5 is formed on the inner wall surface of the bore wall portion 4 of the body body 3 so that the outer peripheral end surface 14a of the valve body 14 when fully closed is in contact therewith.
Note that the valve seal surface 5 and the outer peripheral end surface 14 a are formed in a point-symmetric manner with the left half and the right half in FIG. 3 centering on the rotation axis L of the throttle shaft 8. In the case of FIG. 3, the valve body 14 is opened in the counterclockwise direction (see arrow O in FIG. 3) and conversely closed in the clockwise direction (see arrow S in FIG. 3).

Thus, the valve seal surface 5 has such a shape that the outer peripheral end surface 14a of the valve body 14 can be sealed in the circumferential direction even when the fully closed position of the valve body 14 is shifted in accordance with the contraction of the body body 3. Is formed. That is, the valve seal surface 5 is substantially tapered and has a taper angle θ (see FIG. 3) gradually from the position corresponding to the free end of the valve body 14 toward the bearings 9 and 11 (see FIG. 2). It is formed by a tapered curved surface having a linear cross section that changes slightly. Further, the outer peripheral end surface 14a of the valve body 14 is substantially tapered so as to shape the valve seal surface 5 during resin molding of the body main body 3, and from both positions corresponding to the free end of the valve body 14 It is formed by a tapered curved surface having a linear cross section in which the taper angle θ (see FIG. 3) gradually decreases toward the portions 9 and 11 (see FIG. 2).
The taper angle θ is such that the outer peripheral end surface 14a of the valve body 14 contacts the valve seal surface 5 in the circumferential direction even when the fully closed position of the valve body 14 is shifted in accordance with the contraction amount of the body 3. Set to be possible.

  The shapes of the valve seal surface 5 of the body 3 and the outer peripheral end surface 14a of the valve body 14 will be described in detail. As described above, the valve seal surface 5 and the outer peripheral end surface 14 a are formed so that the left half and the right half in FIG. 3 are point-symmetric about the rotation axis L of the throttle shaft 8. Therefore, hereinafter, the right half portion will be described, and the description of the left half portion will be omitted. In this example, the bore wall 4 of the body 3 contracts uniformly in the circumferential direction by a certain amount in the radial direction. However, the bore wall 4 of the body main body is deformed so that each part in the circumferential direction contracts. If they are different, the shape of the sealing surface corresponding to that, that is, the shape of the outer peripheral end surface 14a of the valve body 14 can be made, and the left half and the right half are not necessarily centered on the rotation axis L of the throttle shaft 8. It need not be symmetrical.

Now, in the relationship between the body body 3 and the right half of the valve body 14 immediately after molding, as shown in FIG. 5A, the surface of the valve body 14 (the surface located on the opening side corresponds) 14A ( Let R be the radius centered on point Pa on FIG. Further, a radius around the point Pb of the back surface (a surface located on the closing side) 14B (see FIG. 5B) of the valve body 14 is defined as r. The point Pb is on a line (referred to as “intake passage axis”) L1 (see FIG. 5B) passing through the center of the bore (intake passage 7). At this time, the radii R and r are
R> r
Satisfy the relationship.
The outer peripheral end surface 14a of the valve body 14 is a tapered curved surface that satisfies the relationship of R> r, that is, is substantially tapered, and both bearing portions 9 and 11 from a position corresponding to the free end portion of the valve body 14 (see FIG. 2 (see FIG. 3), the taper angle θ (see FIG. 3) is formed by a tapered curved surface that gradually changes.

That is, at the position corresponding to the free end of the valve body 14 on the outer peripheral end surface 14a of the valve body 14 formed by a tapered curved surface, the taper angle θ (α) is set (see FIG. 5B). Further, the taper angle θ (β) (see FIG. 5C) is set at a position corresponding to the both bearing portions 9 and 11 (see FIG. 2) of the valve body 14. At this time, the taper angles θ (α) and θ (β) are
θ (α)> θ (β)
Satisfy the relationship. Further, the outer peripheral end surface 14 a of the valve body 14 is tapered from a taper angle θ (α) at a position corresponding to the free end of the valve body 14 to a position corresponding to both the bearing portions 9 and 11 (see FIG. 2). The taper angle θ is gradually reduced toward (β).

Further, at the time of resin molding of the body 3, the valve seal surface 5 of the body 3 is shaped by the outer peripheral end surface 14 a of the valve body 14. Therefore, the valve seal surface 5 formed by the tapered curved surface has a taper angle θ (α) at a position corresponding to the free end portion of the valve body 14 as in the outer peripheral end surface 14a of the valve body 14 (FIG. 5 ( b)), and the taper angle θ (β) (see FIG. 5C) at the positions corresponding to both bearing portions, and the taper angles θ (α) and θ (β) are
θ (α)> θ (β)
Satisfy the relationship. Further, the valve seal surface 5 gradually increases from a taper angle θ (α) corresponding to the free end of the valve body 14 toward a taper angle θ (β) corresponding to both bearing portions. Is formed into a tapered curved surface.
The valve seal surface 5 of the body main body 3 may be formed entirely by the outer peripheral end surface 14a of the valve body 14 during resin molding of the body main body 3, or when the body main body 3 is resin molded. The portion corresponding to the outer peripheral end surface 14a (described later) of the valve body 14 is partially shaped by the outer peripheral end surface 14a of the valve body 14, and the other portions are continuously tapered by the body mold 40 (described later). A curved surface may be formed.

In the relationship between the body body 3 and the valve body 14 after contraction, as shown in FIG. 6A, the bore wall portion 4 of the body body 3 contracts uniformly in the circumferential direction by a certain amount in the radial direction. Shall. Then, the fully closed position of the valve body 14 is deviated by a predetermined angle in the opening direction. At the position corresponding to the free end portion of the valve body 14, the outer peripheral end surface 14 a of the valve body 14 abuts the valve seal surface 5 without a gap ( Specifically, point contact is performed (see FIG. 6B). Further, at a position corresponding to both bearing portions, the outer peripheral end surface 14a of the valve body 14 contacts the valve seal surface 5 without any gap (specifically, point contact) (see FIG. 6C). Similarly, the outer peripheral end surface 14a abuts the valve seal surface 5 almost entirely without any gap in the circumferential direction (specifically, line contact).
Therefore, even when the fully closed position of the valve body 14 is shifted in accordance with the contraction of the body body 3, it is possible to prevent or reduce an increase in the amount of air leakage due to the generation of a gap between the body body 3 and the valve body 14. it can.

On the other hand, assuming the case where the valve seal surface 5 and the outer peripheral end surface 14a are formed with a constant taper angle θ (α) in the circumferential direction, in the relationship between the body body 3 and the valve body 14 immediately after molding, As shown in FIG. 7A, the radius around the point Pa of the surface (surface on the open side) 14A (see FIG. 7B) of the valve body 14 is R. Further, a radius centered on the point Pb of the back surface (surface located on the closing side) 14B (see FIG. 7B) of the valve body 14 is defined as r. The point Pb is on the axis L1 of the intake passage 7 (see FIG. 5B). At this time, the radii R and r are
R> r
Satisfy the relationship.
Further, in the valve seal surface 5 and the outer peripheral end surface 14a formed by the tapered curved surface, the circumferential direction is constant regardless of the position corresponding to the free end portion of the valve body 14 and the position corresponding to the both bearing portions. The taper angle θ (α) is assumed (see FIGS. 7B and 7C).

Then, in the relationship between the body main body 3 and the valve body 14 after contraction, as shown in FIG. 8A, the bore wall portion 4 of the body main body 3 has a certain amount in the radial direction (the same as FIG. 6A). The amount is uniformly shrunk in the circumferential direction. Then, the fully closed position of the valve body 14 is shifted by a predetermined angle in the opening direction. At this time, the outer peripheral end surface 14a of the valve body 14 abuts the valve seal surface 5 without a gap at a position corresponding to both bearing portions (see FIG. 8C). However, at the position corresponding to the free end of the valve body 14, the outer peripheral end surface 14 a of the valve body 14 cannot abut on the valve seal surface 5, so that there is a gap C between the outer peripheral end surface 14 a and the valve seal surface 5. (See FIG. 8B). For this reason, air leakage occurs.
On the contrary, if it is considered that the outer peripheral end surface 14a of the valve body 14 contacts the valve seal surface 5 at a position corresponding to the free end of the valve body 14 (see FIG. 8B), At the corresponding position (see FIG. 8C), the outer peripheral end surface 14a of the valve body 14 and the valve seal surface 5 are stagnated, resulting in malfunction of the valve body 14.

Therefore, when the valve seal surface 5 and the outer peripheral end surface 14a are formed at a constant taper angle θ (α) in the circumferential direction, the valve seal surface 5 of the body main body 3 is moved with respect to the contraction of the body main body 3. Since the outer peripheral end surface 14a of the valve body 14 cannot contact (that is, seal) in the circumferential direction, there is a problem in that the valve body malfunctions and the amount of air leakage increases.
Unlike this, according to the present embodiment, as described above, even when the fully closed position of the valve body 14 is shifted in accordance with the contraction of the body main body 3, the valve seal surface 5 of the body main body 3 is moved. On the other hand, since the outer peripheral end surface 14a of the valve body 14 can be sealed over the circumferential direction, it is possible to prevent or reduce the malfunction of the valve body and the increase in the amount of air leakage.

As shown in FIG. 4, the valve body 14 is cast around the throttle shaft 8, and both end surfaces around the shaft slidably contact the end surfaces of the metal bearings 10 and 12. Thereby, the valve body 14 is positioned with respect to the axial direction. The shaft portion of the throttle shaft 8 cast around by the valve body 14 is, for example, a deformed shaft portion having a substantially oval cross section.
In FIG. 4, the left metal bearing 10 is prevented from coming off to the non-valve side (left side in FIG. 4) by a retaining portion 3 a protruding from the inner wall surface of the bearing portion 9 of the body body 3. . Further, the right metal bearing 12 is prevented from coming off to the non-valve side (left side in FIG. 4) by a retaining portion 3 b protruding from the inner wall surface of the bearing portion 11 of the body main body 3.
Further, in the left bearing portion 9, a rubber seal material 17 that is in contact with the retaining portion 3a is fitted from the opening side (left side in FIG. 4). The inner peripheral portion of the sealing material 17 is slidably fitted in an annular groove 8 c formed in the outer peripheral surface of the throttle shaft 8 and having an annular shape in the circumferential direction. The seal material 17 prevents air leakage from the cover 30 into the intake passage 7 and gas leakage from the intake passage 7 into the cover 30.

Next, a method for manufacturing the throttle body 2 will be described.
This manufacturing method includes a valve molding step and a body molding step.
In the valve molding step, as shown in FIG. 9, the valve body 14 is resin-molded by injection molding using a well-known valve molding die (mold) not shown. At this time, the throttle shaft 8 is inserted in advance in the valve molding die, and the throttle shaft 8 is resin-molded on the valve body 14 by injection molding.

Next, in the body molding step, as shown in FIG. 10, the valve body 14 is inserted into a body molding die (mold) 40 and the body main body 3 (see FIG. 3) is resin molded by injection molding.
The body mold 40 includes an upper mold 41, a lower mold 42 and a plurality of side molds 43 that form a cavity 46 for molding the body 3, an upper auxiliary mold 44 that supports the valve body 14 in the fully closed position, and A lower auxiliary mold 45 is provided. The upper mold 41 is provided with a resin injection port 47 communicating with the cavity 46 from the upper surface thereof.
Then, the molds 41 to 45 are closed while the valve body 14 is inserted and the metal shafts 10 and 12 (see FIG. 4) are fitted to the throttle shaft 8. In this state, the body body 3 is resin-molded by injecting a resin material (molten resin) from the resin injection port 47 into the defined cavity 46 (see FIG. 3).
Next, after the body 3 is cured, the molds 41 to 45 are opened and the product, that is, the throttle body 2 is taken out.
By assembling the plug 16, the sealing material 17, the back spring 19, the motor 20, the reduction gear mechanism 29, the cover 30 and the like to the throttle body 2 manufactured as described above, the throttle control device 1 (FIG. 2) is completed.

In addition, as a resin material used for the above-mentioned body main body 3 and valve body 14, the composite material which uses synthetic resin as a base material (matrix) can be used. Examples of the base material of the synthetic resin include polyester resins such as polyethylene terephthalate and polybutylene terephthalate, polyolefin resins such as polyethylene and polypropylene, polyamide resins such as polyamide 6, polyamide 66, and aromatic polyamide, and ABS. General engineering resin such as polycarbonate and polyacetal, super engineering plastic such as polyphenylene sulfide resin, polyethersulfone, polyetheretherketone, polyethernitrile and polyetherimide, phenol resin, epoxy resin, unsaturated polyester resin, etc. A synthetic resin such as a curable resin, a silicone resin, or a Teflon (registered trademark) resin can be used.
The composite material includes a fiber material and a filling material. For example, fibers such as glass fiber, carbon fiber, ceramic fiber, cellulose fiber, vinylon fiber, brass fiber, and aramid fiber, calcium carbonate, oxide Zinc, titanium oxide, alumina, silica, magnesium hydroxide, talc, calcium silicate, mica, glass, carbon, graphite, thermosetting resin powder, cashew dust and the like can be employed. In some cases, the composite material may be blended with a flame retardant, an ultraviolet ray inhibitor, an antioxidant, a lubricant and the like.

  According to the throttle body 2 described above, the body body 3 is resin-molded by inserting the resin-molded valve body 14. Therefore, a mold having a complicated mold structure for inserting the body 3 is not required, and the mold structure of the mold for resin molding of the body 3 is simplified, thereby reducing costs.

  In Patent Document 1, as described above, since the valve body is resin-molded by inserting the body body, a valve mold corresponding to the dimensions of the body body is required. Considering distortion, that is, molding shrinkage, there remains a problem that a gap between the mold and the body becomes large and molding burrs become large. However, according to the present embodiment, since the body body 3 is resin-molded by inserting the resin-molded valve body 14, an effect that molding burrs can be reduced is also recognized.

Further, the valve seal surface 5 is formed on the inner wall surface of the body 3 so that the outer peripheral end surface 14a of the valve body 14 when fully closed is in contact with the inner wall surface. Even when the valve seal surface 5 of the body body 3 and the outer peripheral end surface 14 a of the valve body 14 are displaced from the fully closed position of the valve body 14 in accordance with the molding shrinkage of the body body 3, the valve seal surface 5 of the body body 3. And the outer peripheral end surface 14a of the valve body 14 (specifically, the outer peripheral edge of the surface located on the closed side) are formed in a shape that can be sealed in the circumferential direction.
Therefore, even when the fully closed position of the valve body 14 is shifted according to the contraction of the body body 3, the outer peripheral end surface 14a of the valve body 14 with respect to the valve seal surface 5 of the body body 3 (specifically , the valve body 14 is positioned on the closed side). The outer peripheral edge of the surface can be sealed over the circumferential direction. Thus, it is possible to reduce or avoid the malfunction of the valve body 14 due to a valve sealing surface 5 of the main body 3 and the outer peripheral end face 14a of the valve body 14 at the time of fully closing bite. At the same time, the outer peripheral end surface 14a of the valve body 14 (specifically, the outer peripheral edge of the surface located on the closed side) seals in the circumferential direction with respect to the valve seal surface 5 of the body 3 so that there is a gap between them. It is possible to prevent or reduce an increase in the amount of air leakage due to the occurrence of air.

  Further, the valve seal surface 5 of the bore wall portion 4 of the body body 3 and the outer peripheral end surface 14a of the valve body 14 are substantially tapered and taper from the position corresponding to the free end of the valve body 14 toward both bearing portions. It is formed by a tapered curved surface in which the angle θ gradually changes. Thereby, even when the fully closed position of the valve body 14 is shifted in accordance with the contraction of the body body 3, the outer peripheral end surface 14 a of the valve body 14 seals in the circumferential direction with respect to the valve seal surface 5 of the body body 3. be able to. Thereby, as described above, it is possible to prevent malfunction of the valve body 14 and increase in the amount of air leakage.

  Moreover, according to the manufacturing method of the throttle body 2 described above, it is possible to easily manufacture the throttle body 2 having the above-described functions and effects.

In addition, by applying a sealing agent to at least one of the valve seal surface 5 of the body main body 3 and the outer peripheral end surface 14a of the valve body 14, the outer peripheral end surface 14a of the valve body 14 and the valve seal surface of the body main body 3 when fully closed. 5 can be improved.
[Example 2]

A second embodiment of the present invention will be described. Since the present embodiment describes an example of changing the shape of the valve body 14 in the first embodiment, a duplicate description is omitted. Similarly, in the following embodiments, duplicate description is omitted.
As shown in FIG. 11, an outer peripheral end surface 14 a corresponding to the valve seal surface 5 of the bore wall portion 4 of the body body 3 is formed in about half of the plate thickness of the valve body 14 of the present embodiment on the closed side. It is.
Also by the throttle body of this embodiment, the same operation and effect as those of the first embodiment can be obtained.
[Example 3]

A third embodiment of the present invention will be described. In this embodiment, a modification of the shapes of the body main body 3 and the valve body 14 in the first embodiment will be described.
As shown in FIG. 12, the valve seal surface 5 of the bore wall portion 4 of the body body 3 of this embodiment has a predetermined amount in the axial direction (vertical direction in FIG. 12) between the left half and the right half in FIG. It is formed by shifting. Correspondingly, the outer peripheral end surface 14a of the left half portion and the outer peripheral end surface 14a of the right half portion of the valve body 14 are formed so as to be shifted by a predetermined amount in the axial direction of the body body 3 (vertical direction in FIG. 12). .
Also by the throttle body of this embodiment, the same operation and effect as those of the first embodiment can be obtained.
[ Related technologies ]

Related technologies will be described. The related art describes a modification of the shapes of the body main body 3 and the valve body 14 in the first embodiment.
As shown in FIG. 13, the valve seal surface 5 of the bore wall portion 4 of the body main body 3 of this embodiment and the outer peripheral end (reference numeral 14 b) of the valve body 14 are attached to the axis L <b> 1 of the intake passage 7. It is formed so as to come into contact with each other at orthogonal surfaces. In this case, the valve seal surface 5 is formed in a flange portion 4 a that protrudes in a flange shape on the inner wall surface of the bore wall portion 4. That is, the fully closed position of the valve body 14 is orthogonal to the axis L <b> 1 of the intake passage 7.
According to the present embodiment, even when the body body 3 contracts, the closed surface of the outer peripheral end portion 14b of the valve body 14 abuts against the valve seal surface 5 of the flange portion 4a of the body body 3 for sealing. be able to. Accordingly, it is possible to prevent or reduce the malfunction of the valve body 14 due to the striking between the valve seal surface 5 of the flange portion 4a of the body body 3 and the outer peripheral end portion 14b of the valve body 14, and An increase in the amount of air leakage due to the generation of a gap between the valve seal surface 5 of the flange portion 4a and the closed surface of the outer peripheral end portion 14b of the valve body 14 can be prevented or reduced. In addition, the outer peripheral end surface 14a of the valve body 14 in the present embodiment is formed by a cylindrical curved surface with the axis L1 of the intake passage 7 as the center.
[Example 4 ]

Embodiment 4 of the present invention will be described. In this embodiment, a modified example in which the shape of the outer peripheral end face 14a of the valve body 14 in the first embodiment is changed will be described. In addition, as described above, the outer peripheral end surface 14a of the valve body 14 is formed such that the left half and the right half in FIG. 3 are symmetric with respect to the rotation axis L of the throttle shaft 8. Therefore, the right half will be described, and the description of the left half will be omitted. Further, in this embodiment, the valve seal surface 5 of the body body 3 is shaped entirely by the outer peripheral end surface 14a of the valve body 14 when the body body 3 is molded with resin.

As shown in FIGS. 14A and 15A, the outer peripheral end surface 14a of the valve body 14 of the present embodiment is basically tapered and the valve body 14 is basically the same as in the first embodiment. A taper having a linear cross section formed by a tapered curved surface in which the taper angle θ (see FIG. 3) gradually changes from the position corresponding to the free end portion toward the bearings 9 and 11 (see FIG. 2). It is formed mainly of a shape portion (reference numeral 14a1 is attached).
Thus, the opening side portion of the outer peripheral end surface 14a of the valve body 14, that is, the large-diameter side portion (the upper portion in FIGS. 14B and 15B) has a convex cross section that is gently continuous with the tapered portion 14a1. An arcuate R-shaped portion 14a2 is formed in the circumferential direction. That is, the outer peripheral end surface 14a of the valve body 14 has a tapered portion 14a1 formed on its closed side portion, that is, a small-diameter side portion, and is smoothly continuous with the tapered portion 14a1 and also has an open side portion, that is, a large diameter. It is comprised by the R-shaped part 14a2 formed in the side part. However, the outer peripheral end surface 14a of the valve body 14 has a tapered curved surface that is substantially the same as described above. The R-shaped portion 14a2 corresponds to a “curved portion” in this specification.

As shown in FIG. 14 (b), the R-shaped portion 14a2 at a position corresponding to the free end of the valve body 14 is a center point P1 (FIG. 14) of a surface 14A located on the open side of the valve body 14. Is formed with a radius R1 (α) centered at. Further, as shown in FIG. 15B, the R-shaped portion 14 a 2 at a position corresponding to the both bearing portions 9 and 11 (see FIG. 2) side of the valve body 14 is located on the opening side of the valve body 14. It is formed with a radius R1 (β) centered on an arbitrary point P2 located on the radius of the surface 14A. At this time, the radii R1 (α) and R1 (β) are
R1 (α)> R1 (β)
Satisfy the relationship. Furthermore, the R-shaped portion 14a2 of the valve body 14 is located on the side of the bearings 9 and 11 (see FIG. 2) from the radius R1 (α) (see FIG. 14B) at a position corresponding to the free end of the valve body 14. Is formed with a radius R that gradually decreases toward a radius R1 (β) (see FIG. 15B) at a position corresponding to. Further, the ratio of the R-shaped portion 14a2 in the outer peripheral end surface 14a of the valve body 14 is determined from the thickness t1 (α) (see FIG. 14B) at the position corresponding to the free end portion of the valve body 14 to the double bearings. It is formed with a thickness t that gradually decreases toward the thickness t2 (β) (see FIG. 15B) at a position corresponding to the side of the portions 9 and 11 (see FIG. 2). In this embodiment, the thickness t1 (see FIG. 14B) is about 70% of the wall thickness t0 on the outer peripheral end surface 14a of the valve body 14, and the thickness t2 (see FIG. 15B) is the thickness. It is about 25% of the thickness t0.

  Therefore, the taper portion 5a1 corresponding to the tapered portion 14a1 and the R-shape are formed on the valve seal surface 5 formed corresponding to the outer peripheral end surface 14a of the valve body 14 at the time of resin molding of the body 3. An R-shaped portion 5a2 corresponding to the portion 14a2 is formed (see FIGS. 14B and 15B). 16A and 16B show the relationship between the body body and the valve body after contraction. FIG. 16A is a sectional view according to FIG. 6B, and FIG. 16B is a partially enlarged view of FIG. FIG. 17 shows the relationship between the body body and the valve body after contraction. FIG. 17A is a cross-sectional view according to FIG. 6C, and FIG. 17B is a partially enlarged view of FIG.

Also with the throttle body of the present embodiment, the same operation and effect as the first embodiment can be obtained. When the body 3 is contracted and the fully closed position of the valve body 14 is shifted, the outer periphery of the valve body 14 is located at the position corresponding to the free end of the valve body 14 as shown in FIG. At a position corresponding to both bearing portions of the valve body 14, the end portion of the tapered surface 14 a 1 of the end surface 14 a is in contact with the valve seal surface 5 of the body body 3 at the point P (α). 17 (b), the taper angle is such that the end on the small diameter side of the tapered portion 14a1 of the outer peripheral end surface 14a of the valve body 14 and the valve seal surface 5 of the body body 3 are in contact at a point P (β). θ (α) (see FIG. 14B) and taper angle θ (β) (see FIG. 15B) are set. And since it is sealed entirely by the linear seal portion formed by the point P (α) (see FIG. 16B) and the point P (β) (see FIG. 17B), The sealing performance between the outer peripheral end surface 14a of the valve body 14 when closed and the valve seal surface 5 of the body 3 can be improved, and the amount of air leakage can be greatly reduced.

  Furthermore, an R-shaped portion 14a2 that is continuous with the tapered portion 14a1 is formed on the large-diameter side portion of the outer peripheral end surface 14a of the valve body 14. Thus, the intake air amount per unit throttle opening (referred to as “intake flow rate”) in the low opening range of the valve body 14 (for example, the opening range of 0 ° to 7 ° when the fully closed position is 0 °). .) Can be reduced.

FIG. 20 is a characteristic diagram showing the low opening degree characteristic of the throttle body. In FIG. 20, the horizontal axis represents the throttle opening (°), and the vertical axis represents the intake flow rate (m ³ / h). Moreover, the characteristic line La is the flow characteristics of the throttle body of the first embodiment, characteristic line Lb flow rate characteristics of the throttle body of the present example (Example 4) are shown, respectively.
As is clear from FIG. 20, according to the throttle body (refer to characteristic line Lb) of the present embodiment (embodiment 4 ), per unit throttle opening in the low opening range (0 ° to 7 °) of the valve body 14. It can be seen that the intake air flow rate is reduced by about 30% compared to the first embodiment (see the characteristic line La).

  Therefore, by reducing the intake flow rate per unit throttle opening in the low opening range of the valve body 14, the decomposition accuracy of the intake flow rate with respect to the throttle opening by the valve body 14 is improved, and the low opening characteristic of the throttle body 2 is improved. Can be improved. Furthermore, by making it possible to reduce the idling speed of the engine, it is possible to exert advantageous effects for improving fuel efficiency and reducing exhaust emissions.

In addition, according to the throttle body of the present embodiment (embodiment 4 ), for example, the improvement effect of the low opening degree characteristic is also obtained as compared with, for example, that of JP-T-2002-530877 (hereinafter referred to as “Patent Document 2”). Can be said to be large. More specifically in this regard, the throttle body of the patent document 2, as shown in FIG. 21, in the intake passage 103 of the resin of the bore wall portion 102, and rotatably supported to the valve body 105 by the throttle shaft 104 A metal cylinder 112 having an inner contour 126 for obtaining a characteristic curve of the intake flow rate in relation to the throttle opening of the valve body 105 is fitted in the bore wall 102. It is a thing. The inner contour 126 of the cylindrical body 112 is point symmetric between the upper portion and the lower portion of the throttle shaft 104, and has a straight cylindrical section 126a on the closed side starting from the fully closed position of the valve body 105. An arcuate section 126b is provided on the opening side.
In the case of Patent Document 2, in order to combine the valve body 105 and the cylindrical body 112 manufactured separately, it is necessary to consider variation in the dimensions of the individual parts (105, 112). That is, when the radius of the valve body 105 Rv, the radius of the arc-shaped segment 126b of the inner contour 126 of the cylinder 112 and the _{R B,}
Rv = _{R B}
Then, the valve body 105 interferes with the arcuate section 126b of the inner contour 126 of the cylindrical body 112, so that the valve body 105 malfunctions. For this reason,
Rv _{<R B}
Must be set to

On the other hand, according to the present embodiment (Example 4 ), the valve body 14 is inserted and the body body 3 is resin-molded, and the valve seal surface 5 of the body body 3 is fitted to the outer peripheral end surface 14a of the valve body 14. By shaping (molding)
Rv = _{R B}
(See FIG. 14A).
Further, the gap due to the difference of the radius R _B and the radius Rv is to become the opening area, the more the difference is small, the intake air flow rate in the low opening range of the valve body 14 is reduced.

Therefore, according to this example (Example 4 ), as described above,
Rv = _{R B}
Therefore, by reducing the intake flow rate in the low opening range of the valve body 14, it is possible to improve the resolution accuracy of the intake flow rate with respect to the throttle opening by the valve body 14. For this reason, since the improvement effect of a low opening degree characteristic can be utilized to the maximum, even if compared with the said patent document 2 (refer FIG. 21 ), it can be said that the improvement effect of a low opening degree characteristic is large.

In addition, the improvement effect of the low opening degree characteristic can be freely selected by changing the ratio of the tapered portion 14a1 and the R-shaped portion 14a2 of the outer peripheral end surface 14a. Incidentally, as the ratio of the R-shaped portion 14a2 is larger than that of the tapered portion 14a1, the intake flow rate per unit throttle opening in the low opening range of the valve body 14 can be reduced, and the throttle opening by the valve body 14 can be reduced. The decomposition accuracy of the intake flow rate with respect to can be improved, and the low opening degree characteristic of the throttle body 2 can be improved. For this reason, the R-shaped portion 14a2 only needs to be formed on at least the large-diameter side portion of the outer peripheral end surface 14a of the valve body 14, and can be formed entirely on the outer peripheral end surface 14a.

Further, according to the present embodiment (embodiment 4 ), it is possible to reduce the cost for the following reason as compared with the first embodiment. For example, when the valve body 14 of the first embodiment is molded with resin, a small chamfered R portion 15 is formed at the open side, that is, the corner portion on the large diameter side of the outer peripheral end surface 14a of the valve body 14 (see FIG. 18). ). In FIG. 18, the R portion 15 is exaggerated.
For this reason, as shown in FIG. 18, when the valve body 14 is inserted and the body main body 3 is resin-molded by the body molding die 40, the R portion 15 is formed between the upper auxiliary die 44 and the valve body 14. The molten resin flows into the minute space created by Thereby, a molding burr | flash generate | occur | produces in the body main body 3 of the shape | molded product. When the valve body 14 opens, this molded burr may interfere with the inner wall surface of the intake passage 7 (see FIG. 3) and cause the valve body 14 to malfunction. In such a case, it is necessary to remove the molding burr of the body 3 by post-processing.

On the other hand, in the throttle body of the present embodiment (embodiment 4 ), an R-shaped portion 14a2 is formed on the large-diameter side portion of the outer peripheral end surface 14a of the valve body 14 (FIGS. 14B and 15B). )reference). The angle θt formed by the tangent Lt of the R-shaped portion 14a2 (in the first embodiment, the outer peripheral end surface 14a having a tapered curved surface) and the surface 14A located on the opening side of the valve body 14 is compared to the first embodiment. The angle becomes larger, that is, an angle close to 90 °. Thereby, the R part 15 (refer FIG. 18) formed by resin molding of the valve body 14 can be made small. As the angle θt becomes larger (closer to 90 °), the R portion 15 (see FIG. 18) of the valve body 14 becomes smaller.
Therefore, by reducing the molding burr of the body 3 caused by the R portion 15 of the valve body 14 to a level that does not hinder the operation of the valve body 14, the removal work of the molding burr can be omitted .

[Example 5 ]

A fifth embodiment of the present invention will be described with reference to the drawings. In this embodiment, a modified example of the fourth embodiment will be described. That is, as shown in FIG. 22 , an R-shaped portion 14a2 (see FIG. 14B) formed on the open side portion, that is, the large-diameter side portion of the outer peripheral end surface 14a of the valve body 14 in Example 4 is tapered. Instead of the elliptical portion 14a3 having a convex cross-sectional elliptical shape that is gently continuous with the shaped portion 14a1. Accordingly, an elliptical portion 5a3 corresponding to the elliptical portion 14a3 is formed on the valve seal surface 5 that is shaped corresponding to the outer peripheral end surface 14a of the valve body 14 during resin molding of the body main body 3.
Also according to the present embodiment, the same actions and effects as in the fourth embodiment can be obtained. The elliptical portion 14a3 and the R-shaped portion 14a2 (see the fourth embodiment) of the valve body 14 may be involute, quadratic curve, cubic curve, or the like that approximates an arc in addition to the above-described embodiment. Good. In addition, the outer peripheral end surface 14a of the valve body 14 may have a tapered curved surface that is substantially the same as described above, and the elliptical portion 5a3 (or the R-shaped portion 14a2) has a plurality of stages with different curvatures. It can be formed by combining an elliptical part or an R-shaped part and them .
[Example 6 ]

A sixth embodiment of the present invention will be described with reference to the drawings. In this embodiment, a modified example of the fourth embodiment will be described. That is, as shown in FIG. 23 , an R-shaped portion 14a2 (see FIG. 14B) formed on the open side portion, that is, the large-diameter side portion of the outer peripheral end surface 14a of the valve body 14 in the fourth embodiment is tapered. Instead of the taper portion 14a4 having a linear cross section that is continuous with the shape portion 14a1. The taper angle θ4 of the tapered portion 14a4 is set smaller than the taper angle θ (α) of the tapered portion 14a1. Accordingly, an elliptical portion 5a4 corresponding to the tapered portion 14a4 is formed on the valve seal surface 5 which is shaped corresponding to the outer peripheral end surface 14a of the valve body 14 during resin molding of the body main body 3.
Also according to the present embodiment, the same actions and effects as in the fourth embodiment can be obtained. The outer peripheral end surface 14a of the valve body 14 is not limited to the two-step tapered portions 14a1 and 14a4, but may be three-steps having different taper angles as a whole. It can be formed by the above tapered part, and can be formed in a shape including at least one elliptical part or R-shaped part .

  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.

It is a front view which shows the throttle control apparatus concerning Example 1 of this invention. It is the II-II sectional view taken on the line of FIG. FIG. 3 is a cross-sectional view taken along line III-III in FIG. 1. FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 3. The relationship between the body body and the valve body immediately after molding is shown. (A) is a plan view of the valve body, (b) is a cross-sectional view taken along line AA in (a), and (c) is (a). It is BB sectional view taken on the line. It shows the relationship between the body body and the valve body after contraction, (a) is a plan view of the body body, (b) is a cross-sectional view taken along line AA of (a), and (c) is (a). It is BB sectional view taken on the line. The valve seal surface shows the relationship between the body body and the valve body immediately after molding when the valve seal surface is formed with a constant taper angle in the circumferential direction. (A) is a plan view of the valve body, and (b) is (a) ) Is a cross-sectional view taken along line A-A in FIG. FIG. 2 shows the relationship between the body body and the valve body after contraction when the valve seal surface is formed with a constant taper angle in the circumferential direction, (a) is a plan view of the body body, and (b) is (a). ) Is a cross-sectional view taken along line A-A in FIG. It is a rough body sectional view showing a valve body before fabrication of a body main part. It is a rough body sectional view showing a body mold. It is sectional drawing which shows the throttle body concerning Example 2 of this invention. It is sectional drawing which shows the throttle body concerning Example 3 of this invention. It is sectional drawing which shows the throttle body concerning the related technology of this invention. FIG. 5 shows a relationship between a body body and a valve body immediately after molding of a throttle body according to Example 4 of the present invention, in which (a) is a sectional view according to FIG. 5 (b), and (b) is a valve of (a). It is a disassembled sectional view which shows the relationship between the outer peripheral end surface of a body, and the valve seal surface of the bore wall part of a body main body. The relationship between the body body and the valve body immediately after the molding of the throttle body is shown. (A) is a sectional view according to FIG. 5 (c), (b) is the outer peripheral end surface of the valve body and the body body of (a). It is a disassembled sectional view which shows the relationship with the valve seal surface of a bore wall part. The relationship between the body main body and valve body after contraction is shown, (a) is a sectional view according to FIG. 6 (b), and (b) is a partially enlarged view of (a). The relationship between the body main body and the valve body after contraction is shown, (a) is a sectional view according to FIG. 6 (c), and (b) is a partially enlarged view of (a). It is explanatory drawing concerning description of the shaping | molding burr | flash at the time of resin molding of the body main body. It is explanatory drawing which shows the effect by the R-shaped part of the valve body at the time of resin molding of a body main body. It is a characteristic diagram which shows the low opening degree characteristic of a throttle body. It is sectional drawing which shows an example of the conventional throttle body. It is a disassembled sectional view which shows the relationship between the outer peripheral end surface of the valve body concerning Example 5 of this invention, and the valve seal surface of the bore wall part of a body main body. It is a disassembled sectional view which shows the relationship between the outer peripheral end surface of the valve body concerning Example 6 of this invention, and the valve seal surface of the bore wall part of a body main body.

2 Throttle body 3 Body body 7 Intake passage 5 Valve seal surface 5a1 Tapered part 5a2 R-shaped part (curved part)
14 Valve body 14a Outer peripheral end surface 14a1 Tapered portion 14a2 R-shaped portion

Claims (2)

A body body in which an intake passage is formed;
A throttle body provided with a valve body rotatably provided on the body body and opening and closing the intake passage by the rotation;
The valve body is resin molded,
The body body is resin-molded by inserting the valve body in a fully closed position ,
The outer peripheral end surface of the valve body is tapered such that the outer diameter gradually decreases from the surface located on the opening side of the valve body toward the surface located on the closing side, and the position corresponding to the free end of the valve body Formed from a tapered curved surface in which the taper angle gradually decreases from both bearing parts to
A throttle body characterized in that a valve seal surface is formed on an inner wall surface of the body body by an outer peripheral end surface of the valve body by inserting the valve body and resin-molding the body body. The throttle body according to claim 1 ,
A throttle body characterized in that a curved portion is formed at least on the large diameter side portion of the outer peripheral end face of the valve body.

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