JPH01247882A - Duct structure - Google Patents

Abstract

PURPOSE:To enhance the rigidity of an entire duct and prevent the duct from being crushed by a negative pressure or the like by forming the duct of rubber or plastic used for the suction system or the like of an internal combustion engine and interposing a reinforcement member between opposite internal surfaces of a large curvature radius portion of the duct. CONSTITUTION:A suction duct 11 made of rubber or plastic is formed in a 3-dimensionally curved shape with a cross section extending laterally to show an ellipsoid. Straight line portions 11a, 11a at the front and rear and a curved portion 11b in the center of the duct of a large radius are provided at their internal opposite large curvature radius central portions with opposite pair of holding grooves 13, 13 between projections extending along the axial direction of the duct. Reinforcement members 15 are disposed in the holding groove 14.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a duct structure used, for example, in an intake system of an internal combustion engine for an automobile.

As is well known in the prior art, in an internal combustion engine for an automobile, an intake duct 3 made of rubber or synthetic resin is disposed between the engine body l and the air cleaner 2, as shown in FIG. ing.

By the way, a large suction negative pressure is generated inside the intake duct 3 during engine operation, and the intake duct 3 is likely to be crushed inward and deformed. Therefore, the flow resistance of the intake air increases, and the efficiency of filling the intake air into the combustion chamber decreases.

Therefore, according to the conventional intake duct structure, for example, as shown in FIG. An annular holding groove 5 is formed between the annular protrusions 4 and 4, and within the holding groove 5, the dividing points 6a and 7a are formed at 90°.
A double ring-shaped reinforcing member 6.7 with a phase shift of 6.7° is mounted. Then, by the reinforcing member 6.7,
This prevents the intake duct 3 from collapsing inward due to negative suction pressure.

Problems to be Solved by the Invention However, in the conventional duct structure described above, since the intake duct 3 has a substantially perfect circular shape with uniform wall thickness, the direction in which it collapses is not determined, and therefore the reinforcing member 6. 7 must be formed into an annular shape.

The reinforcing member 6.7 has divided parts 6a and 7a from the viewpoint of ease of attachment to the holding groove 5. Therefore, in order to strengthen the stress in the vertical and horizontal directions, one holding groove 5 has two parts. Two reinforcing members 6, 7 are required.

As a result, not only does the installation work of the reinforcing members 6 and 7 become complicated, but the number of parts increases, resulting in poor manufacturing efficiency.
There is a problem of high cost.

Means for Solving the Problems The present invention was devised in view of the problems of the conventional duct structure described above. It is characterized by a reinforcing member interposed between opposing inner surfaces having a large radius.

Effects According to the present invention having the above-mentioned configuration, since the cross-sectional shape is elliptical, the rigidity in the diametrical direction on the side with the small radius of curvature is increased, and therefore the reinforcing member in the diametrical direction of the part with the small radius of curvature is becomes unnecessary. Therefore, as mentioned above, it is only necessary to provide a reinforcing member between opposing surfaces having a large radius of curvature, that is, in the diametrical direction.
There is no need to provide two reinforcing members at each location.

EXAMPLES Hereinafter, examples of the present invention will be described in detail based on the drawings. still,
Each embodiment shows an application to an intake duct of an internal combustion engine for an automobile, as in the conventional case.

FIGS. 1A and 1B show a first embodiment of the present invention, and a second embodiment of the present invention is shown in FIGS.
The figure shows the overall configuration of the intake duct 11. That is, the intake duct 11 is made of rubber or synthetic resin.
The entire structure is three-dimensionally bent, and its cross section has a substantially elliptical shape extending left and right. Further, the vertically opposing inner surfaces 12.1 having a large radius of curvature between the front and rear straight portions 11+lL and Ila of the intake duct 11 and the central bent portion 11b
A pair of upper and lower retaining grooves 14 are formed between protrusions 13 degrees 13 that protrude along the axial direction from approximately the center of each of the retaining grooves 14, and reinforcing members 15 are formed within the retaining grooves 14.・are respectively retained. This reinforcing member 15... has the shape of a single plate made of synthetic resin, and its height is the upper and lower holding grooves 14...
14 The holding groove 1 is set slightly larger than the length between the bottom surfaces.
4.14 is press-fitted and fixed.

Therefore, the intake duct 11 of this embodiment has high rigidity in the left and right portions with a small radius of curvature, while the top and bottom portions with a large radius of surface area are strengthened by the reinforcing members I5. Collapse due to pressure is reliably prevented. Moreover, the upper and lower holding grooves 14... respectively!
Since the reinforcing members 15 are simply press-fitted from the front and rear ends of the intake duct 11, the installation work is extremely easy, and the reduction in the number of parts improves manufacturing workability.

Furthermore, since the intake air led from the air cleaner into the intake duct il is rectified and guided downstream along both surfaces 15a and 15a of the reinforcing member 15, it is quickly supplied to the engine combustion chamber, and the filling efficiency of the intake air is improved. improves. In particular, the bending part zb
In the vicinity, drifting of the air to the left and right to the blade side due to the inertial force of the intake air is prevented.

FIG. 3 shows a second embodiment of the present invention. In this embodiment, the reinforcing member 15 is formed by bending a wire spring steel into a rectangular shape instead of a plate, so that the reinforcing member 15 can be elastically supported. Therefore, the vibration noise of the intake duct 11 can also be suppressed.

FIGS. 4(A) and 4(B) show a third embodiment of the present invention, in which the retaining grooves of the first embodiment are eliminated, and the upper and lower ends of a plate-shaped reinforcing member 15 made of synthetic resin are Intake duct 1
A curved support portion 16.16 extending in the circumferential direction of the support portion 1 is integrally molded, and the whole is formed into a substantially horizontal H shape. Also,
The length between the support portions 16.16 is set larger than the length between the opposing inner surfaces 12.12 of the intake duct 11 having a large radius of curvature. Therefore, not only can the same reinforcing and rectifying effects as in the first embodiment be obtained, but also the engineering work of the reinforcing member 15 into the intake duct ll is facilitated by the support parts 16 and 16, and the retaining groove is Due to abolition,
Therefore, the manufacturing workability of the intake duct 11 itself is improved.

5A and 5B show a fourth embodiment of the present invention, in which a reinforcing member 15 made of synthetic resin is formed to have a substantially rectangular cross section, and intake ducts 11 are provided above and below the reinforcing portion 115. An axially extending support 17.17 is integrally formed. Others are third
The configuration is similar to that of the embodiment. Therefore, the manufacturing workability of the intake duct 11 itself is improved by eliminating the holding groove, and the overall weight can be reduced by downsizing the reinforcing member 15.

6(A) and 6(B) show a fifth embodiment of the present invention, in which a reinforcing member 15 is formed by twisting and bending wire spring steel into an approximately figure 8 shape, and upper and lower portions 15a and 15b are used for air intake. The structure is such that the bullet is loaded inside the duct 11. The reinforcing member 15 is disposed along the axial direction or the radial direction on the upper and lower opposing inner surfaces 12.12 of the intake duct It. Therefore, in this case as well, effective elastic support of the intake duct 11 is obtained, and
Since retaining grooves and the like are eliminated, the work of forming the intake duct 11 itself becomes easier.

Each of the embodiments is extremely practical because each reinforcing member 15 not only causes little flow resistance of intake air due to its structure and arrangement within the intake duct 11, but also has a rectifying effect. . Furthermore, the reinforcing member 15 may be provided at a predetermined location within the intake duct 11.

Further, the present invention provides 1. The invention is not limited to the intake duct as in each embodiment, but can also be applied to ducts in other equipment.

Effects of the Invention As is clear from the above explanation, according to the duct structure according to the present invention, a duct made of rubber or synthetic resin is formed into a substantially elliptical cross section, and the duct has a large radius of curvature between opposing inner surfaces. Since the reinforcing member is inserted, the overall rigidity of the duct is increased and collapse due to negative pressure is reliably prevented, and there is no need to provide two reinforcing members in one place as in the past. One is enough. Therefore, the work of attaching the reinforcing member is facilitated, and the manufacturing efficiency is improved by reducing the number of parts, and costs can be reduced.

[Brief explanation of the drawing]

FIG. 1(A) is I- of FIG. 2 showing the first embodiment of the present invention.
2 is a cross-sectional view taken along the line ■--■ of FIG. 2 (A), FIG. 4(A) is a sectional view taken along the line II in FIG. 2 showing the third embodiment of the present invention; FIG. 4(B) is a sectional view taken along Figure (A) is a sectional view taken along the line I-I in Figure 2 showing the fourth embodiment, and Figure (B)' is the same figure (
A) is a sectional view taken along the line IV-IV, FIG. 6(A) is a sectional view taken along the line II of FIG. 2 showing the fifth embodiment, and FIG.
FIG. 7 is a schematic diagram showing an intake system of an internal combustion engine to which the intake duct is applied, and FIG. 8 is a partial sectional view showing a conventional duct structure. 11...Intake duct, 12...Opposing inner surface, 15...
・Reinforcement member. 2nd person outside 4th ff1 (A) Figure 4 (B) Figure 5 (A)
Figure S (B) Figure 6 (A) Figure 6 (B) Figure 7 Figure 8

Claims (1)

[Claims] (1) A duct structure characterized in that a duct made of rubber or synthetic resin is formed to have a substantially elliptical cross section, and a reinforcing member is interposed between opposing surfaces of the duct having a large radius of curvature.