JPH1162637A - Intake device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an intake device for internal combustion engines, the whole body of which is molded of a resin, and which can highly accurately form the bore inner peripheral wall section of an intake passage and the bearing section of a throttle shaft. SOLUTION: A throttle body 10 comprises plastic body 11 comprising a bore inner peripheral wall section 13 surrounding a throttle valve 2 out of an intake passage and a boss section 14 integrally formed and a plastic body 12 forming other sections. Forming the body 11 into a simple cylinder-like shape eliminates the shrinkage and unevenness of the body 11 when it is molded, which provides a highly accurate molded body. For the body 11, resin of excellent properties such as high accuracy, high strength and excellent environmental resistance is used. The whole of the throttle body 10 can be lighten and be made at a low cost by using light and low cost material for the body 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to an internal combustion engine (hereinafter referred to as "internal combustion engine").
The present invention relates to an intake device for an "internal combustion engine", and more particularly to an intake device for an engine using a resin as a material of a throttle body (hereinafter, the intake device for an engine is referred to as a throttle device).

[0002]

2. Description of the Related Art In recent years, in order to reduce the weight and cost of a throttle device, it has been known to form a throttle body from a resin material. Since particularly high dimensional accuracy is required for the inner wall of the bore of the intake passage and the bearing portion of the throttle shaft, as disclosed in Japanese Utility Model Publication No. 2-41328, metal around the inner wall of the bore and the bearing is provided. Molded with resin and the rest molded with resin,
As disclosed in Japanese Patent Application Laid-Open No. 04249, there is known a resin-made throttle body in which a metal or resin ring-shaped insertion member is embedded at right angles to an intake passage.

[0003]

However, in the conventional throttle device disclosed in Japanese Utility Model Publication No. 2-41328, a gap is formed at the mating surface of metal and resin due to shrinkage and sink during resin molding. There is.
In this case, the air in the intake passage flows through the gap due to the differential pressure between the upstream and downstream of the throttle valve. In particular, when the valve is fully closed, there is a problem that the idle speed increases due to an increase in the engine intake air amount.

In the throttle device disclosed in Japanese Patent Publication No. 8-504249, a bore inner peripheral wall surrounding a throttle valve is formed integrally with a throttle body having a complicated shape. If the throttle body is deformed due to assembly or temperature change, the inner wall of the bore is also likely to be deformed by the effect.When the throttle valve is fully closed, air flows downstream from the clearance between the throttle valve and the inner wall of the bore to the intake downstream side. There is a possibility that the throttle valve may leak or come into contact with the inner peripheral wall surface of the bore, preventing smooth rotation of the throttle valve.

[0005] Further, both of the above-mentioned prior arts have a problem that, when high and low temperatures are repeated, a gap is enlarged due to a difference in linear expansion coefficient between the metal and the resin, and in the worst case, the resin is broken. In addition, fitting a metal member to the inner wall of the resin throttle body reduces the advantage in terms of weight reduction by using resin.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and the entire throttle body is formed of a resin material, and the inner peripheral wall of the intake passage and the bearing of the throttle shaft are formed with high dimensional accuracy. It is an object of the present invention to provide a throttle device that can perform the throttle operation.

[0007]

According to the throttle device of the present invention, the throttle body is formed of a resin material in order of the intake inner wall surrounding the throttle valve and the remainder other than the intake inner wall. Therefore, the weight of the entire throttle body can be reduced as compared with the case where a metal material is used for the inner wall of the intake, and shrinkage at the time of resin molding which occurs when a metal material is used, generation of a gap due to sink, and linear expansion. The expansion of the gap due to the difference in the coefficients can be prevented. In addition, since the intake inner wall surrounding the throttle valve can be manufactured with higher dimensional accuracy than when the entire throttle body is integrally formed of resin, air leaks to the intake downstream side when the valve is fully closed, or the throttle valve is It is possible to prevent the smooth rotation of the throttle valve from being hindered by contacting the inner wall surface.

According to the throttle device of the second aspect of the present invention, since the intake inner wall portion and the remaining portion are formed of different resin materials, the intake inner wall portion is made of a material having high precision, high strength and excellent environmental resistance. The remainder can be formed of a lightweight and inexpensive material having excellent weldability and machinability. As a result, it is possible to achieve both the weight reduction and cost reduction of the entire throttle body, as well as the high accuracy and durability improvement of the intake inner wall portion.

According to the throttle device of the third aspect of the present invention, since the bearing portion of the throttle body that supports the throttle shaft is simultaneously formed of the same resin material as the inner wall portion of the intake, the bearing portion of the throttle body is raised. It can be manufactured with dimensional accuracy. Therefore, the throttle valve can rotate smoothly.

[0010]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a first embodiment of the present invention; FIGS. 1, 2 and 3 show a first embodiment of the present invention. The throttle device 1 forms an intake passage to an engine and controls an intake flow rate. Butterfly type throttle valve 2
Is formed of a metal such as aluminum or brass,
It is sandwiched by the throttle shaft 3 and screwed. Both ends of the throttle shaft 3 are rotatably supported by bearings 4.

An accelerator lever 5 provided at one end of the throttle shaft 3 is connected to an accelerator pedal (not shown) operated by a driver, and rotates according to the amount of depression of the accelerator pedal. The throttle shaft 3 and the throttle valve 2 rotate with the rotation of the accelerator lever 5, and the intake flow rate is controlled. The spring 6 urges the accelerator lever 5 in the fully closed direction, and the accelerator lever 5 is locked by the fully closed stopper 7 to define the fully closed position of the throttle valve 2. Also, the accelerator lever 5 is fully opened stopper 8
, The full open position of the throttle valve 2 is defined.

A rotation angle sensor 16 is attached to the other end of the throttle shaft 3. The rotation angle sensor 16
The rotation angle of the throttle shaft 3, that is, the opening of the throttle valve 2 is detected, and an opening signal is transmitted from the connector 161 to an ECU (not shown) which is an engine control device. The pipe 15 is for taking out a negative pressure in the intake passage. ISC
The (Idle Speed Control) unit 17 controls the amount of air passing through a flow path (not shown) that bypasses the throttle valve 2 when the engine is in an idle state, so that an optimum idle speed is adjusted according to the engine coolant temperature and the engine load. It is for setting to.

The throttle body 10 includes a resin body 11 in which a bore inner peripheral wall 13 as an intake inner wall, which is a portion surrounding the throttle valve 2 in the intake passage, and a boss 14 are integrally formed. And a resin body 12 as a remaining portion forming a portion. The order in which the body 11 and the body 12 are molded is as follows.
May be either earlier or later. Also, the body 11 and the body 1
As a molding method for integrating the two, there are insert molding in which the body 11 and the body 12 are formed in separate processes and inserted into a mold, and two-color molding in which both members are molded in the same process.

When the throttle valve 2 is in a fully closed state, the body 11 does not cause galling between the bore inner peripheral wall portion 13 and the throttle valve 2 and prevents air from leaking from the gap. It is necessary to set the clearance between the part 13 and the throttle valve 2 with high accuracy. The bearing 4 is fixed to the boss 14 as a bearing, and supports the throttle shaft 3. If the accuracy of the boss 14 is low, smooth rotation of the throttle valve 2 may be hindered. In the present embodiment, by forming the body 11 to have a shape close to a simple cylinder, it is possible to perform molding with high precision without nonuniform shrinkage and distortion during molding. Therefore,
The bore inner peripheral wall 13 and the boss 14 can be formed with high precision. Further, even when the shape of the throttle body 10 is changed, the same body 11 can be used, so that the accuracy of the body 11 does not change every time the throttle body 10 changes.

In the present embodiment, a resin having properties such as high precision, high strength, and excellent environmental resistance is used for the body 11. For example, resins such as PPS and aromatic nylon can be used. Therefore, the dimensional accuracy and durability of the body 11 are improved, and the bore inner peripheral wall portion 13 and the boss portion 14 are improved.
Can be prevented from being deformed. As a result, the throttle valve 2 rotates smoothly, and the intake air flow rate can be controlled with high accuracy. Since the amount of resin used for the body 11 is small in the entire throttle body 10, even if the cost is somewhat high, material selection giving priority to required performance can be performed.

Since the pipe 15 and the like are welded to the body 12, it is desirable to use a material having a low melting point and excellent weldability. Further, since the rotation angle sensor 16 and the ISC unit 17 are attached to the body 12 with a tapping screw or the like, it is desirable to use a material having good machinability. Further, if the body 12 is bolted to fix the throttle body 10 to another intake pipe, the body 12 may be deformed. However, if the body 12 is formed of a soft resin, the deformed portion may be formed. It becomes only a portion near the bolted portion, and deformation of the intake passage can be prevented. Furthermore, since the body 12 occupies most of the volume of the throttle body 10, the weight and cost of the entire throttle body 10 can be reduced by using a lightweight and low-cost material for the body 12. As a material of the body 12, for example, a resin such as polyamide or PBT (polybutylene terephthalate) can be used. Body 11
And the body 12 may be formed of the same kind of resin material.

When a part of the resin throttle body is formed of metal, there is a problem that a gap is generated at the mating surface between the resin part and the metal part. In this embodiment, both bodies 11 and 12 are formed. Because it is a resin, it fits well and there is no gap due to shrinkage or sink during molding. Further, since the difference between the coefficients of linear expansion of the bodies 11 and 12 is smaller than that of the case where metal is used, even if the temperature changes, no gap or crack occurs. Further, the weight of the entire throttle body 10 can be reduced as compared with the case where metal is used.

FIG. 4 is a partially broken sectional view showing a second embodiment of the present invention. The substantially same parts as those in the first embodiment are denoted by the same reference numerals. In the first embodiment, the bore inner peripheral wall 13 and the boss 1
4 are integrally formed as the body 11, but it is also possible to form only the bore inner peripheral wall portion 13 as the body 110 and the remaining portion as the body 120 as shown in FIG.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view of a throttle device according to a first embodiment of the present invention as viewed in the direction of arrow I in FIG. 2;

FIG. 2 is a plan view showing a throttle device according to a first embodiment of the present invention.

FIG. 3 is a cross-sectional view taken along line AA of FIG. 1 showing the throttle device according to the first embodiment of the present invention;

FIG. 4 is a partially broken cross-sectional view illustrating a throttle device according to a second embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Throttle device 2 Throttle valve 3 Throttle shaft 4 Bearing 5 Accelerator lever 6 Spring 7 Fully-closed stopper 8 Fully-opened stopper 10 Throttle body 11 Body 12 Body (remaining part) 13 Bore inner peripheral wall part (intake inner wall part) 14 Boss part (bearing part) 15 Pipe 16 Rotation angle sensor 17 ISC section

Claims (3)

[Claims] 1. An intake device for an internal combustion engine, comprising: a throttle body forming an intake passage; and a throttle valve rotatably housed in the throttle body and controlling an intake flow rate in the intake passage. An intake device for an internal combustion engine, wherein a throttle body is formed of a resin material in order of an intake inner wall surrounding the throttle valve and a remaining portion other than the intake inner wall. 2. The intake device for an internal combustion engine according to claim 1, wherein the inner wall portion of the intake and the remaining portion are formed of different kinds of resin materials. 3. The throttle body of the throttle body, which rotatably supports a throttle shaft of the throttle valve, is formed of the same resin material as the inner wall of the intake at the same time. The intake device for an internal combustion engine according to any one of the above.