JP2005273563A - Throttle body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent an outer peripheral face of a valve element from biting into a body main body, to realize a good close contact state between the outer peripheral face of the valve element and a valve seal face of the body main body and to obtain a stable intake air flow rate, without setting severe molding conditions for countermeasures against contraction caused by resin molding. <P>SOLUTION: This throttle body 1 is provided with the body main body 10 on which a cylindrical intake passage 14 is formed and the disk-shaped valve element 20 rotatably arranged on the body main body 10 and opening/closing the intake passage 14 by the rotation. The valve element 20 is molded of resin, and the outer peripheral face 21 of the valve element 20 is formed to have an inclined face shape of which diameter is enlarged in the opening direction of the valve element 20. The body main body 10 comprising the valve element 20 inserted into therein is molded of resin, and is formed by projecting the valve seal face 12 of the body main body 10 at the time of full closing of the valve element 20 from an inner wall face 11 of the body main body 10, taking the outer peripheral face 21 of the valve element 20 as a molding face. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a throttle body. In particular, the present invention relates to a throttle body that controls the amount of intake air by forming a part of an intake passage of an internal combustion engine.

  2. Description of the Related Art Conventionally, a throttle body (also referred to as an air flow control device or a throttle chamber) is provided with a body body in which a cylindrical intake passage is formed and a valve body that is rotatably provided in the body body and opens and closes the intake passage. )It has been known.

  A conventional throttle body is shown in FIG. 11, FIG. 12, and FIG. 11 is a transverse sectional view of the vicinity of a valve body of a conventional throttle body, and FIG. 12 is a sectional view taken along line XII-XII in FIG. FIG. 13 is a longitudinal sectional view corresponding to FIG. 12 conceptually showing molding shrinkage of the body.

  The throttle body 1 has a body body 10 and a valve body 20. The body 10 made of resin has a hollow cylindrical shape and forms an intake passage 14. The resin valve body 20 has a disk shape, is integrally formed by casting a metal shaft 30, and resin reinforcing ribs 22 are appropriately provided on both front and back surfaces of the valve body 20. . The valve body 20 rotates with the rotation of the shaft 30 supported by the bearing 13, thereby creating a gap between the outer peripheral surface 21 of the valve body 20 and the valve seal surface 12 of the body body 10. The amount of air passing through the intake passage 14 is controlled. As shown in FIGS. 11 and 12, when the valve body 20 is fully closed, the outer peripheral surface 21 of the valve body 20 can be brought into close contact with the valve seal surface 12 of the body body 10. The controllability of the intake air amount is improved.

Here, in order to improve the close contact state of the intake passage 14 when the valve body 20 is fully closed, the outer peripheral surface 21 of the valve body 20 and the valve seal surface 12 of the body main body 10 are in close contact contact during resin molding. Although the method of making it conventionally is performed, there exists a problem that molding shrinkage arises by resin hardening after that in resin molding.
In Patent Document 1, as a countermeasure for this, molding is performed by separating the molding space of the body main body 10 and the molding space of the valve body 20 by a predetermined interval in consideration of the subsequent contraction during resin molding. A method is employed in which the molding shrinkage rate of the resin material used for molding the body 10 is made smaller than the molding shrinkage rate of the resin material used for molding the valve body 20.
JP 2000-210983 A

However, it is practically difficult to manage the mold shrinkage such that the outer peripheral surface 21 of the valve body 20 comes into close contact with the valve seal surface 12 of the body main body 10 after the mold shrinkage. As a result, there is a problem in that the contact contact state as intended is not obtained.
In particular, under severe conditions for bringing the outer peripheral surface 21 of the valve body 20 into close contact with the valve seal surface 12 of the body body 10 after molding shrinkage, it is difficult to manage the conditions. Even if it is in a good tight contact state as described above, molding shrinkage may occur in the direction of the arrow 40 shown in FIG. 13 due to subsequent resin curing. As a result, the valve body 20 bites into the inner wall surface 11 of the body main body 10, and the valve body 20 becomes unable to rotate.

  The present invention was devised in view of such points, and the problem to be solved by the present invention is that the outer peripheral surface of the valve body bites into the body body without imposing severe molding conditions for measures against resin molding shrinkage. The object is to obtain a good tight contact state between the outer peripheral surface of the valve body and the valve seal surface of the body body. Furthermore, in addition to the problem, it is to obtain a stable intake air flow rate.

In order to solve the above problems, the present invention takes the following means.
First, the throttle body according to the first invention takes the following means. That is, a throttle body comprising a body body in which a cylindrical intake passage is formed, and a disc-shaped valve body that is rotatably disposed in the body body and opens and closes the intake passage by the rotation. The valve body is resin-molded, and its outer peripheral surface is formed into an inclined surface shape whose diameter increases in the opening direction of the valve body. The body body is resin-molded by inserting the valve body, and the outer periphery of the valve body The surface of the body of the valve body when the valve body is fully closed is formed by projecting from the inner wall surface of the body of the valve body, and the flow rate control near the fully closed state of the valve body is the rotation of the valve body. This is performed by changing the gap between the valve seal surface and the inner wall surface of the body main body.
According to the first aspect of the present invention, even if the body shrinkage occurs due to insert molding of the valve body, the contact position between the valve seal surface of the body body and the outer peripheral surface of the valve body shifts so Contact property is maintained. Further, even when the deviation does not occur, the biting of the valve body into the inner wall surface of the body main body can be compensated. Furthermore, by adjusting the step size between the inner wall surface of the body body and the valve seal surface protruding from the inner wall surface, the flow rate characteristic in the vicinity of the fully closed state of the valve body can be controlled.

The throttle body according to the second invention takes the following means. That is, in the throttle body according to the first invention described above, the flow rate control in the vicinity of the fully closed state of the valve body is a gap between the outer peripheral surface of the valve body and the valve seal surface and the inner wall surface of the body body. It is characterized in that the change is made by a configuration that is a smooth continuous change.
According to the second aspect of the invention, in the vicinity of the fully closed state of the valve body, the passage path of the intake air is from a path where the gap between the outer peripheral surface of the valve body and the valve seal surface of the body body is dominant. It is possible to reduce discontinuous gap changes when the gap between the outer peripheral surface and the inner wall surface of the body body transitions to a dominant path.

The throttle body according to the third invention takes the following means. That is, in the throttle body according to the first or second invention described above, the outer peripheral surface of the valve body and the body main body when the rotational position of the valve body is separated from the valve seal surface protruding from the body main body. The gap dimension relationship between the valve seal surface and the inner wall surface of the valve body is the shortest gap dimension between the outer peripheral surface of the valve body and the valve seal surface of the body body, and the outer peripheral surface of the valve body and the inner wall surface of the body body. The shortest gap dimension between them is formed to be substantially the same dimension.
According to the third aspect of the present invention, the intake air flow rate control near the fully closed state of the valve body is controlled by the flow rate control based on the gap size between the outer peripheral surface of the valve body and the valve seal surface of the body body. It is possible to substantially eliminate the discontinuous flow rate change that occurs when the flow control is performed by the dimension of the gap between the surface and the inner wall surface of the body body.

The present invention can obtain the following effects by taking the above-mentioned means.
According to the first invention, the valve body due to the molding contraction of the body body without adversely affecting the flow rate characteristics near the fully closed state of the valve body without performing molding contraction management that strictly defines the mold and the resin material. Can be prevented.
Further, according to the second invention, it is possible to reduce the discontinuous intake air flow rate change in the vicinity of the fully closed valve body.
Further, according to the third aspect of the invention, in the vicinity of the fully closed state of the valve body, the passage path of the intake air is from the path where the gap between the outer peripheral surface of the valve body and the valve seal surface of the body body is dominant. Discontinuous gap change when the gap between the outer peripheral surface of the body and the inner wall surface of the body transitions to the dominant path can be virtually eliminated, and stable at all rotational positions of the valve body The obtained intake air flow rate can be obtained.

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

  Example 1 is shown in FIGS. 1 is a cross-sectional view of the vicinity of a valve body of a throttle body according to this embodiment, FIG. 2 is a cross-sectional view taken along the line II-II of FIG. 1, FIG. 3 is a cross-sectional view taken along the line III-III of FIG. 2 is a one-side sectional view corresponding to FIG. 2 when the rotational position is slightly separated from the valve seal surface of the body body, and FIG. 5 is a one-side sectional view when further spaced apart from FIG. In the present embodiment, the parts corresponding to the parts of the conventional structure shown in FIGS. 11 to 13 are denoted by the same reference numerals.

First, the structure of the throttle body according to this embodiment will be described with reference to FIGS.
The throttle body 1 has a resin body body 10 and a resin valve body 20, and FIGS. 1 to 3 show a case where the valve body 20 is in a fully closed position.
As shown in FIG. 2, the body body 10 has an inner wall surface 11 that forms a cylindrical intake passage 14 inside thereof, and a valve body 20 in the circumferential direction of the intake passage 14 in the circumferential direction. A valve seal surface 12 is provided in contact with the outer peripheral surface 21 of the valve. Here, the valve seal surface 12 protrudes from the inner wall surface 11 of the body main body 10 by a predetermined step size. Further, the body 10 is provided with metal bearing portions 13 for disposing the valve body 20 at opposite portions of the intake passage 14 in the diameter direction of the cross section.

  On the other hand, the disc-shaped valve body 20 is integrally formed by casting around the shaft 30 having an oval cross-section, and is rotatably supported by a bearing portion 13 provided in the body main body 10. Since the shaft 30 has an oval cross section, the valve body 20 follows the rotation of the shaft 30 without idling. Further, in order to withstand the stress of the intake air flow, a plurality of reinforcing ribs 22 are arranged in parallel on the front and rear surfaces of the valve body 20 in a direction from the central axis of rotation of the valve body 20 toward the outer peripheral surface 21. It is provided as appropriate.

As shown in FIG. 3, a bearing seal portion 23 is formed in a portion of the outer periphery of the valve body 20 that abuts on the bearing portion 13 of the body body 10. It is configured to flow through the intake passage 14 without leaking from the portion 13. On the other hand, as shown in FIG. 2, an inclined surface shape (so-called taper shape) that expands in the opening direction (counterclockwise direction) of the valve body 20 is provided at a portion that contacts the valve seal surface 12 of the body body 10. ) Is formed. The valve body 20 and the body body 10 are also provided with a similar inclined surface shape on the valve seal surface 12 of the body body 10 with which the outer peripheral surface 21 of the valve body 20 abuts when the valve body 20 is fully closed. It is the structure where the contact | abutting contact state with is obtained.
In addition, although the cross section is drawn as a straight line in FIG. 2, this taper shape may be a curve as long as the rotation of the valve body 20 and the close contact state of the outer peripheral surface 21 are not hindered.

Next, the molding process of the throttle body 1 will be described. This molding process includes a molding process for the valve body 20 and a molding process for the body 10.
First, the valve body 20 is molded by resin injection using a known valve mold (mold). That is, the shaft 30 is inserted into the valve mold, and the resin is injected into the molding space of the shape of the valve body 20, so that the resin is filled around the shaft 30 and the outer periphery of the valve body 20. A shaped valve body 20 is formed.
Secondly, the body 10 is molded by inserting the valve body 20 molded in the above process and injecting a resin into the molding space of the shape of the predetermined body 10. At this time, since the resin is filled along the outer peripheral surface 21 of the valve body 10, the valve seal surface 12 of the body main body 10 that substantially matches the outer peripheral surface 21 is formed.

Here, in the molding process of the body body 10, molding shrinkage occurs as the post-molding body body 10 is cured. For this reason, the valve body 20 may bite into the inner wall surface 11 of the body main body 10. In the present embodiment, the following two methods shown in FIG. 2 are used as methods for preventing the bite.
The first method is that the outer peripheral surface 21 of the valve body 20 is formed in an inclined surface shape whose diameter increases in the opening direction of the valve body 20. Thus, even when the valve seal surface 12 of the body body 10 is molded and contracted in the inward direction, the fully closed position of the valve body 20 is rotated so as to deviate by a predetermined angle in the opening direction. The contact with the seal surface 12 is maintained.
The second method is that the valve seal surface 12 of the body main body 10 is formed on the end surface of the protruding portion 15 that protrudes from the inner wall surface 11 of the body main body 10 by a predetermined step size. Thus, even if the outer peripheral surface 21 of the valve body 20 relatively pushes out the valve seal surface 12 without shifting as intended in the first method, the body body 10 having the valve seal surface 12 protrudes. Since the portion 15 is only pushed into the body body 10, the valve body 20 itself does not bite into the body body 10.

Next, the intake air flowing through the intake passage 14 of the throttle body 1 near the fully closed state of the valve body 20 will be described with reference to FIGS. 4 and 5.
First, as shown in FIG. 4, in the vicinity of the fully closed valve body 20, when the valve body 20 is slightly rotated counterclockwise, that is, in the opening direction, the outer peripheral surface 21 of the valve body 20 is A clearance is formed between the valve body 12 and the valve seal surface 12 of the body 10. The intake air flowing from the upper part to the lower part of the intake passage 14 passes through the clearance.
Next, as shown in FIG. 5, even when the valve body 20 is in the vicinity of the fully closed state, when the valve body 20 is further rotated in the opening direction, the outer peripheral surface 21 of the valve body 20 is now moved to the body. A gap is formed between the main body 10 and the inner wall surface 11, and the intake air passes through the gap.

That is, as the opening degree of the valve body 20 increases, the clearance path between the outer peripheral surface 21 of the valve body 20 and the valve seal surface 12 of the body body 10 is dominant in the passage path of the intake air flowing through the intake passage 14. From the passage route, the clearance dimension between the outer peripheral surface 21 of the valve body 20 and the inner wall surface 11 of the body body 10 transitions to a dominant passage route.
Therefore, if these gap sizes are adjusted by the step size provided between the valve seal surface 12 and the inner wall surface 11 in the body body 10, the passage path of the intake air can be controlled. Furthermore, the flow rate of the intake air can be controlled.

Example 2 is shown in FIGS. Since the present embodiment shows a modified example of the projecting portion 15 provided in the body main body 10 according to the first embodiment, a duplicate description is omitted.
Here, FIG. 6 is a conceptual diagram showing an air inflow path in which the gap between the outer peripheral surface of the valve body and the valve seal surface of the body body is dominant in the throttle body according to this embodiment, and FIG. FIG. 8 is an air flow rate / valve opening curve obtained by the throttle body. FIG. 8 is a conceptual diagram showing an air inflow path in which the gap between the surface and the inner wall surface of the body body is dominant.

  First, as well shown in FIGS. 6 and 7, the protruding portion 15 of the body body 10 according to the present embodiment has a size that can sufficiently compensate for molding shrinkage after the body body 10 is molded. In other words, by sufficiently increasing the step size of the protrusion 15 provided between the valve seal surface 12 and the inner wall surface 11 in the body main body 10, the effect of compensating the molding shrinkage after the molding of the body main body 10 is achieved. It is increasing.

  Next, the flow of intake air in the present embodiment will be described with reference to FIGS. Here, L1 is the shortest gap dimension that represents the gap between the outer peripheral surface 21 of the valve body 20 and the valve seal surface 12 of the body body 10, and L2 is the outer wall surface 21 of the valve body 20 and the inner wall surface of the body body 10. 11 is the shortest gap dimension representative of the gap between the two. Here, the reason that the gap between each surface is represented by the shortest gap dimension is that it is simple to set the gap dimension between each surface to only one, and in the flow control of the air flowing into the gap. This is because the shortest gap size is dominant. Hereinafter, the shortest gap dimension is simply referred to as “gap dimension”.

As shown in FIG. 6, in the vicinity of the fully closed state of the valve body 20, the intake air flows as indicated by an arrow 41 through a passage route in which the gap dimension L <b> 1 is dominant. However, the intake air flowing through the passage route in which the gap dimension L2 is dominant is as indicated by an arrow 41 shown in FIG. 7, and the flow rate of the intake air is greatly increased compared to the case of FIG.
Therefore, even when the valve body 20 is slightly rotated in the opening direction, the flow rate of the intake air is discontinuous by the transition from the passage path in which the gap dimension L1 is dominant to the passage path in which the gap dimension L2 is dominant. Result in an increase.

This is shown in FIG. That is, the flow rate of the intake air rapidly increases discontinuously when the opening degree of the valve body 20 is around 5 degrees. This discontinuous point coincides with a point where the gap dimension L1 transitions from a dominant passage path to a dominant passage path of the gap dimension L2. Such discontinuities indicate that the intake air amount of the internal combustion engine suddenly increases and is not preferable in the design of the internal combustion engine.
This tendency becomes more prominent as the difference between the gap dimension L1 and the gap dimension L2 is larger. Therefore, paying attention to the flow rate of the intake air of the throttle body 1 in addition to the compensation for molding shrinkage, the protruding portion of the body body 10 It is necessary to determine 15 step dimensions.

  Example 3 is shown in FIGS. The present embodiment shows a modification of the protruding portion 15 provided in the body main body 10 according to the second embodiment. FIG. 9 is an enlarged sectional view on one side showing the relationship between the valve body and the body of the throttle body according to this embodiment, and FIG. It is an opening curve.

  As described in the second embodiment, the gap dimension L1 between the outer peripheral surface 21 of the valve body 20 and the valve seal surface 12 of the body main body 10, the outer peripheral surface 21 of the valve body 20, the inner wall surface 11 of the body main body 10, and the like. Since there is a discontinuity in the flow rate of the intake air due to the large difference between the gap dimension L2 between the two, the difference between the gap dimension L1 and the gap dimension L2 is substantially guaranteed while guaranteeing molding shrinkage compensation. It is desirable to eliminate them. By doing so, it is possible to obtain a stable intake air flow rate in which no discontinuity occurs at all the rotational positions of the valve body 20.

Therefore, as shown in FIG. 9, by determining the step size of the protruding portion 15 of the body body 10, a desirable relationship between the minimum gap dimension L1 and the minimum gap dimension L2 can be obtained. Here, T is the thickness of the protruding portion 15 of the body body 10 and the thickness of the valve body 20, C is the radius of the intake passage 14, and θ is the diameter of the outer peripheral surface 21 of the valve body 20 in the opening direction of the valve body 20. It is an inclination angle. Further, the gap dimension L1 ₀ is a dimension from the lower surface end portion 20b of the valve body 20 to the upper surface end portion 15a of the protruding portion 15 of the body body 10, and the gap dimension L2 ₀ is a distance between the upper surface end portion 20a of the valve body 20 and the body body 10. It is the dimension up to the inner wall surface 11.

Note that the gap dimensions L1 ₀ and L2 ₀ shown in FIG. 9 are the gap dimensions L1 and L2 in a plane in which the lower surface end 20b of the valve body 20 includes the upper surface of the protruding portion 15 of the body body 10 (see FIG. 9). 6). The reason why the rotational position of the valve body 20 is set to this position is that this position is a boundary point (a point of intake air flow rate control in which the gap dimension L1 transitions from a passage path where the gap dimension L1 is dominant to a passage path where the gap dimension L2 is dominant. (Discontinuous point).

At this time, if the condition of L1 ₀ ≈L2 ₀ is satisfied, the difference in gap size for controlling the intake air at the transition boundary point is substantially eliminated. Therefore, as shown in FIG. An air flow / valve opening curve that cannot be obtained is obtained.
In this embodiment, the conditions are T = 2 mm, C = 22.5 mm, and θ = 10 °.

  The dimensional relationship described above also holds for the entire contact surface between the valve seal surface 12 of the body body 10 and the outer peripheral surface 21 of the valve body 20. Therefore, the adhesiveness of the entire contact surface is kept good.

FIG. 3 is a cross-sectional view of the vicinity of the valve body of the throttle body according to the first embodiment. It is the II-II sectional view taken on the line of FIG. It is the III-III sectional view taken on the line of FIG. FIG. 3 is a one-side sectional view corresponding to FIG. 2 when the rotational position of the valve body is slightly separated from the valve seal surface of the body body. FIG. 5 is a one-side cross-sectional view corresponding to FIG. 2 when further separated from FIG. 4. FIG. 9 is a conceptual diagram showing an air inflow path in which a gap dimension between an outer peripheral surface of a valve body and a valve seal surface of a body body is dominant in a throttle body according to a second embodiment. FIG. 9 is a conceptual diagram showing an air inflow path in which a gap dimension between an outer peripheral surface of a valve body and an inner wall surface of a body of the throttle body according to the second embodiment is dominant. 6 is an air flow rate / valve opening curve obtained with the throttle body according to the second embodiment. FIG. 9 is a one-side enlarged cross-sectional view showing a relationship such as a gap dimension between a valve body and a body body of a throttle body according to a third embodiment. 10 is an air flow rate / valve opening curve obtained in a modification of the throttle body according to the third embodiment. It is a cross-sectional view near the valve body of a conventional throttle body. It is the XII-XII sectional view taken on the line of FIG. It is a longitudinal cross-sectional view of the conventional throttle valve which shows notionally the shrinkage | contraction of a body main body.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Throttle body 10 Body main body 11 Inner wall surface 12 Valve seal surface 13 Bearing part 14 Intake passage 15 Projection part 15a Projection part upper surface end part 20 Valve body 20a Upper surface end part 20b Lower surface end part 21 Outer peripheral surface 22 Rib 23 Bearing seal part 30 Shaft 40 Shrinkage direction 41 Air flow 42 Valve body center line
L1 The shortest clearance dimension between the outer peripheral surface 21 of the valve body 20 and the valve seal surface 12 of the body body 10
L2 The shortest clearance dimension between the outer peripheral surface 21 of the valve body 20 and the inner wall surface 11 of the body body 10

Claims (3)

A throttle body comprising a body body formed with a cylindrical intake passage, and a disc-shaped valve body that is rotatably disposed in the body body and opens and closes the intake passage by the rotation,
The valve body is resin-molded, and the outer peripheral surface is formed in an inclined surface shape that expands in the opening direction of the valve body,
The body body is formed by resin molding by inserting the valve body, and the valve seal surface of the body body is projected from the inner wall surface of the body body when the valve body is fully closed with the outer peripheral surface of the valve body as a molding surface. And
A throttle body characterized in that the flow rate control near the fully closed state of the valve body is performed by a change in a gap between a valve seal surface and an inner wall surface of the body main body as the valve body rotates. The throttle body according to claim 1,
The throttle is characterized in that the flow rate control near the fully closed state of the valve body is performed by a configuration in which a gap change between the valve body and a valve seal surface and an inner wall surface of the body body is a smooth and continuous change. Body. The throttle body according to claim 1 or 2,
The clearance dimension relationship between the outer peripheral surface of the valve body and the valve seal surface and the inner wall surface of the body body when the rotational position of the valve body is separated from the valve seal surface protruding from the body body is The shortest clearance dimension between the outer peripheral surface and the valve seal surface of the body body and the shortest clearance dimension between the outer peripheral surface of the valve body and the inner wall surface of the body body are formed to be substantially the same dimension. Throttle body characterized by

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