JP2002021656A - Intake device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an intake device capable of correctly controlling an intake air amount with a clamping structure not producing excessive stress strain in the peripheral part of a throttle valve of a throttle body. SOLUTION: Since airtightness is kept by fitting annular elastic seal members 2 and 4 having plural annular lip parts 2a, 2b, 4a and 4b tilting toward the atmosphere into seal slots 1b and 1d formed in the circumference of the entrance part and the circumference of the exit part of the throttle body 1 and by fitting cylindrical seal parts 3a and 5a formed on an air duct 3 and an intake manifold 5, fitting load as well as clamping force are small as compared with a conventional one, so that the excessive stress strain is not produced in the peripheral part of the throttle valve 31 of the throttle body 1 and the intake quantity can correctly be controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intake device for an internal combustion engine, and more particularly, to a throttle body and an air duct.
And a connection structure with an intake manifold.

[0002]

2. Description of the Related Art In a fuel injection type internal combustion engine, as shown in FIG. 2, a throttle body 21 made of synthetic resin for controlling the amount of intake air and an air cleaner (not shown) for purifying the intake air. Is connected to an air duct 22 made of synthetic resin extending from the air duct 22 via an elastic seal member 24 on an air duct mounting portion 23 of the throttle body 21. Is tightened by a clamp 27 that tightens the band-shaped band 26 by the fastening force of the port 25, whereby the airtightness is maintained by the spool 21b and the elastic seal member 24 provided on the air duct mounting portion 21a of the throttle body 21, and the clamp 27 Generally, a structure for preventing the detachment by the fastening force of the above is used. FIG. 4 of Japanese Unexamined Utility Model Publication No. 8-68 discloses a method of joining by a clamp as a method of fastening and fixing an end of a resin-made intake duct with a fastening band.

The throttle body 21 and the intake manifold 23 made of synthetic resin are connected to a plurality of mounting holes 21d formed in a flange portion 21c of the throttle body 21 via O-rings 32 with a plurality of bolts 28. Is being done. Flange part 21 of throttle body 21
c is a hollow annular bracket 33 withstanding the tightening force of the bolt 28.
However, the flange portion 2 of the intake manifold 23
A screw fitting 34 having a female thread engaged with the bolt 28 is inserted into 3a at the time of molding or after molding.

A cylindrical intake passage 29 is formed through the throttle body 21 so as to penetrate the throttle shaft 30 so as to be rotatable across the intake passage 29. Has been fixed. The throttle valve 31 is opened and closed by rotation of a throttle lever (not shown) fixed to one end of the throttle shaft 30, and the gap area between the outer peripheral portion of the throttle valve 31 and the inner wall of the intake passage 29 of the throttle body 21 is determined. The intake air amount is controlled to guide the intake air to the internal combustion engine.

[0005]

However, in the above-described method of coupling with the air duct 22, since the bolt tightening force of the clamp 27 is as large as 500 to 1000 kgf, when the throttle body 21 is made of synthetic resin. When tightened, the air duct mounting portion 21a of the throttle body 21 may be distorted, and the stress distortion may reach the throttle body 21 around the throttle valve 31. In addition, in the above-described method of coupling with the intake manifold 23, a deformation force of about 70 kgf is required for the O-ring 32 in order to secure the air-tightness of the O-ring 32.

When applying this deformation force to the O-ring 32,
The tightening force of the bolt 28 causes distortion in the throttle body 21 around the throttle valve 31, and in any case, the intake passage 29 is deformed into an elliptical shape, and the throttle valve opening is small when the small air amount is small. In some cases, the intake air amount cannot be controlled, and the idling control of the internal combustion engine cannot be performed correctly. Therefore, when the present invention attaches the throttle body to the air duct and the intake manifold,
An object of the present invention is to provide a mounting structure in which an excessive tightening force is not applied to a throttle body and stress distortion at the time of mounting can be reduced and accurate intake air amount control can be performed.

[0007]

According to a first aspect of the present invention, there is provided a throttle body made of synthetic resin for controlling an intake air amount by opening and closing a throttle valve, and an air cleaner. In an intake system for an internal combustion engine comprising an air duct for guiding the intake air to the throttle body to the throttle body and an intake manifold for guiding the intake air measured by the throttle body to the combustion chamber, an outer periphery of an inlet portion and an outer periphery of an outlet portion of the throttle body. The annular elastic seal member having a plurality of annular lip portions inclined toward the atmosphere is fitted into the seal groove provided in
The airtightness is maintained by fitting a cylindrical seal portion provided on the air duct and the intake manifold to the elastic seal member. Also, the invention of claim 2 is characterized in that the dimensions of each part of the two seal grooves and the two elastic seal members are the same, and that the two elastic seal members are assembled in such a manner that the assembling directions are upside down. It is characterized in that a kind of elastic seal member is shared.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described with reference to the drawings. Note that the same parts as those in the related art are denoted by the same reference numerals, and description thereof will be omitted. FIG. 1 is a longitudinal sectional view of an intake device according to one embodiment of the present invention. In FIG. 1, an annular seal groove 1b is formed on an outer periphery of an inlet portion of a cylindrical intake passage 1a constituting the throttle body 1. The seal groove 1b has two lip portions 2a, 2b
An annular elastic seal member 2 made of rubber having

Each of the lips 2a and 2b is formed to have a predetermined angle and to be inclined in one direction. A cylindrical seal portion 3a is formed at the outlet of the air duct 3, is fitted around the elastic seal member 2, and is fixed to the throttle body 1 by fastening means (not shown). Cylindrical seal part 3
When "a" is assembled, the lip portions 2a and 2b are mounted to the atmosphere side of the throttle body 1 so as to face. At this time, the upstream end 1c of the throttle body 1 comes into contact with the locking portion 3b of the air duct 3. The number of the lips 2a and 2b is not limited to two as long as it is plural.

An annular seal groove 1d is also formed on the outer periphery of the outlet of the intake passage 1a, and a rubber elastic seal member 4 having two lip portions 4a and 4b is fitted in the seal groove 1d. Each of the lip portions 4a and 4b is formed to have a predetermined angle and to be inclined in one direction. A cylindrical seal portion 5a is formed at the entrance of the intake manifold 5, and the cylindrical seal portion 5a is fitted around the elastic seal member 4, and is connected to the throttle body 1 by a fastening means (not shown) via a flange portion 1e. Will be concluded.

When the cylindrical seal portion 5a is fitted to the elastic seal member 4, the lip portions 4a,
b Assembled so that the tip faces the atmosphere side of the throttle body 1. At this time, the downstream end 1 of the throttle body 1
f comes into contact with the locking portion 5b of the intake manifold 5. The number of the lip portions 4a and 4b is sufficient if it is plural.
However, the present invention is not limited to this, and is similar to the above-described elastic seal member 2. It is economical if two seal grooves 1b and 1d are formed to have the same dimensions, and the two elastic seal members 2 and 4 are used as one kind and shared.

Next, the operation of the present embodiment will be described. Throttle body 1 is intake manifold 5
When the air duct 3 is assembled to the throttle body 1, the respective cylindrical seal portions 3a, 5a
a is a lip portion 2 of each elastic seal member 2, 4
a, 2b, 4a, and 4b are aligned and assembled at the tips of the tips. Since the lip portions 2a, 2b, 4a, 4b are tapered toward the tip, the cylindrical seal portions 3a,
The load when 5a is fitted is not excessive as compared with the prior art, and can be fitted with approximately 10 to 20 kgf, and the fastening force by the fastening means (not shown) can be smaller than in the prior art.

Therefore, after fastening, the throttle body 1
No harmful tightening stress is generated around the throttle valve 31, and the intake air amount of the throttle valve 31 can be controlled correctly. In addition, the lip portions 2a of the elastic seal members 2, 4,
Since the assembled directions of 2b, 4a, and 4b are assembled toward the atmosphere side, they are deformed so as to be dense against the negative pressure in the intake passage 1a, so that sufficient airtightness is secured. In addition, since a plurality of lip portions are provided, even if one of the lip portions is damaged or leaked, the other lip portion supports it, thereby ensuring airtightness.

[0014]

The present invention has the following effects because it is configured as described above. That is, when the throttle body is connected to the air duct and the intake manifold, no harmful tightening stress is generated around the throttle valve of the throttle body, so that the intake amount of the throttle valve can be correctly controlled. Further, since the lip portion of the elastic seal member is deformed so as to be tight against the negative pressure in the intake passage, sufficient airtightness can be secured.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of an intake device according to an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of a conventional intake device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Throttle body 1b Seal groove 1d Seal groove 2 Elastic seal member 2a Lip part 2b Lip part 3 Air duct 3a Cylindrical seal part 4 Elastic seal member 4a Lip part 4b Lip part 5 Intake manifold 5a Cylindrical seal part

Claims (2)

[Claims] 1. A throttle body made of a synthetic resin for controlling an amount of intake air by opening and closing a throttle valve, an air duct for guiding intake air cleaned by an air cleaner to the throttle body, and a throttle body measured by the throttle body. An intake device for an internal combustion engine comprising an intake manifold for guiding intake air to a combustion chamber, wherein a plurality of annular lip portions inclined toward the atmosphere side are provided in seal grooves provided on an outer periphery of an inlet portion and an outer periphery of an outlet portion of the throttle body. An internal combustion engine wherein airtightness is maintained by fitting an annular elastic seal member and fitting a cylindrical seal portion provided on the air duct and the intake manifold to the elastic seal member. Intake device. 2. The two seal grooves and the two elastic seal members have the same dimensions, and the two elastic seal members are assembled so that the assembling direction of the two elastic seal members is upside down. The intake device for an internal combustion engine according to claim 1, wherein the members are shared.