JPH0291467A - Reinforcing structure of air duct for introducing negative pressure - Google Patents

Abstract

PURPOSE:To exert no bad influence on ventilation resistance of introduced air, saving configuration space by fitting a hard ring-like member with the substantially same diameter as the outside diameter of a duct to the outer peripheral surface of an air duct. CONSTITUTION:When negative pressure is applied to an air duct 1 fitted to a ring-like member 5 at the time of introducing outside air, a portion of the outer peripheral portion thereof is a little deformed to cave in the diametral direction. Whereupon, though a part orthogonal to the portion deformed to cave in escapes outward to be deformed, the outward relief deformation is restrained because the ring-like member 4 retains it s circular shape so that the air-duct 1 will not be crushed. Furthermore, the ring-like member 4 has the substantially same diameter as that of the air duct 1 not to be projected out, so that it can be arranged in the minimum space not obstructing the configuration of peripheral devices. It is not necessary to provide any reinforcing member in the air duct 1 so that ventilation resistance is not increased so as to exert no bad influence on an engine.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a reinforcement structure for an air duct for introducing negative pressure air used, for example, as an outside air introduction path of an internal combustion engine.

BACKGROUND OF THE INVENTION Negative pressure acts on an air duct for introducing combustion air in an automobile depending on the operating conditions of the engine, and in some cases, the air duct collapses and deforms (as shown in FIG. 3). This crushing deformation often occurs in a form where the cross-sectional area becomes A=A', but various reinforcing structures are available to prevent this.

For example, as shown in FIG. 4, reinforcing ribs 2 are formed on the outer peripheral surface of the air duct l to prevent crushing deformation;
Alternatively, as shown in FIG. 5, a coil spring 3 is disposed on the inner peripheral surface of the air duct 1 to counteract the crushing force.

Problems to be Solved by the Invention The reinforcing structure in which the ribs 2 are provided on the outer peripheral surface of the air duct 1 has a problem in that the ribs 2 protrude outside the air duct 1 and require a large amount of space for arrangement.

In addition, with a reinforced structure in which a coil spring 3 is provided on the inner circumferential surface of the air duct 1, the above-mentioned problem regarding the installation space does not occur, but the spring 3 increases the ventilation resistance when introducing outside air. There is a problem in that the engine performance is adversely affected.

Therefore, the present invention provides a reinforcement structure for an air duct for introducing negative pressure air that does not take up much space and does not adversely affect the ventilation resistance of the introduced air.

Means for Solving the Problem A hard annular member having approximately the same diameter as the duct outer diameter is attached to the outer peripheral surface of the air duct.

By suppressing the part that tends to be pushed outward when the working air duct collapses and deforms, with an annular member from the outside,
Prevents crushing and deformation.

Example Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

In Fig. 1.2, ``■'' indicates an air duct made of resin or rubber, which is interposed between an air cleaner (not shown) and the engine.

Annular members 4 made of hard resin (or stainless steel) are attached to the outer peripheral surface of the air duct 1 at predetermined intervals.

This annular member 4 is in the form of a belt, and is fixed by inserting the tip portion 4b into the buckle portion 4a.The annular member 4 has a thin wall so as not to protrude from the outer peripheral surface of the air duct l as much as possible when attached. is used.

Incidentally, instead of the above-mentioned band type, a ring-shaped member made of metal such as stainless steel may be used and fitted onto the outer periphery of the air duct 1.

Further, the annular member 4 has a shape-retaining property that maintains its circular shape even when the air duct 1 is crushed and deformed.

According to the above embodiment structure, when negative pressure acts on the air duct 1 to which the annular member 4 is attached when introducing outside air, the second
As shown in the figure, a portion of the outer circumferential portion is slightly depressed and deformed in the diametrical direction.

Along with this, a part that is perpendicular to the part that has undergone the above-mentioned depressed deformation tries to escape and deform outward, but since the annular member 4 is kept in a circular shape, the above-mentioned outward escape deformation occurs. is suppressed and therefore the air duct l
It does not cause any crushing deformation.

Furthermore, since the annular member 4 has approximately the same diameter as the air duct 1, it does not protrude outward, and is therefore advantageous in that it can be arranged in a minimum space that does not prevent the arrangement of peripheral equipment.

Since no reinforcing member is required inside the air duct 1, the ventilation resistance will not increase and adversely affect the engine.

Furthermore, according to experiments, 190U is lost if no measures are taken.
! When resin annular members are attached at intervals of 50RN to an air duct that collapses and deforms due to Hg, -115ixHg
The crushing deformation pressure increases to -25utHg, and the stainless steel annular member is installed at
It was revealed that the crushing deformation pressure increases to -110iu+Hg when attached at v intervals.

In this way, the air duct 1 can be effectively reinforced with a simple structure in which the annular member 4 is attached to a necessary part after molding.

As described in detail, according to the present invention, crushing deformation of any part can be reliably prevented without restricting the installation space of peripheral equipment or increasing the ventilation resistance of introduced air. It has the effect of being able to prevent this.

[Brief explanation of the drawing]

FIG. 1 is a plan view of an embodiment of the present invention, FIG. 2 is a cross-sectional view of the deformed state along the line ■-■ in FIG. 1, FIG. The plan view, FIG. 5, is a plan sectional view of another prior art. l... Air duct 4... Annular member. External 4 people Figure 4 Exit■ Figure 2

Claims (1)

[Claims] (1) A reinforcement structure for an air duct for introducing negative pressure air, characterized in that a hard annular member having approximately the same diameter as the duct outer diameter is attached to the outer peripheral surface of the air duct.