JP4692338B2 - Bellows hose - Google Patents

Description

  The present invention relates to a rubber bellows hose used for an air cleaner hose and the like.

  The air cleaner hose 100 of the automobile is disposed between the air cleaner 200 and the engine 300 as shown in FIG. The air cleaner hose generally has straight pipe portions 101 and 103 at both ends, and a bellows pipe portion 102 is formed between the first straight pipe portion 101 and the second straight pipe portion 103 to enhance vibration resistance. . The air cleaner hose 100 is generally formed by injection molding from a synthetic rubber such as CR or EPDM.

  By the way, when forming a bellows hose having a bellows tube portion by injection molding, a core for forming the inner peripheral surface of the bellows tube portion is used, and after the molding, a mold release operation for removing the bellows hose from the core is required. Become. However, since the bellows tube portion is undercut with respect to the center core, it is difficult to release as it is. Therefore, by utilizing the fact that it is made of rubber that is easily elastically deformed, it is possible to release mold while inflating the bellows hose by injecting pressurized air between the inner peripheral surface of the bellows hose and the outer peripheral surface of the core. It has been broken.

  However, depending on the shape of the bellows tube, it may be difficult to release the mold by being caught by the center core. In addition, a part of the bellows tube portion climbs on the center, and pressurized air leaks from that portion, which makes expansion difficult, which may make mold release difficult.

  Therefore, Japanese Utility Model Laid-Open No. 63-128382 proposes a bellows hose in which one unit of the saddle constituting the bellows tube portion is composed of an upright wall in the radial direction of the hose and an oblique wall continuous to the upright wall. Yes. By setting it as such a bellows part, an undercut becomes weak with a slanting wall, and mold release becomes easy.

Japanese Utility Model Laid-Open No. 05-027485 describes that in an air cleaner hose having a clamp portion on the outer peripheral surface, a groove is formed in the clamp portion. By doing in this way, since the rigidity of a clamp part falls and a deformation | transformation becomes easy, mold release work can be performed smoothly.
Japanese Utility Model Publication No. 63-128382 Japanese Utility Model Publication No. 05-027485

  However, depending on the shape of the bellows tube, it may be difficult to obtain the structure described in the above publication. For example, if the bellows tube portion of the air cleaner hose is a bellows tube portion having a slanted wall as described in Patent Document 1, vibration resistance performance and negative pressure resistance performance may deteriorate. Further, the inclined wall increases the length of one bellows unit in the axial direction, and the desired number of bellows units may not be formed. Therefore, when ensuring the vibration resistance performance or the number of bellows units, there is a problem that the inclined wall cannot be formed, making it difficult to release the mold and increasing the man-hour of the worker.

  In the case of a curved bellows hose in which the central axis of the straight pipe portion intersects with the central axis of the bellows pipe portion continuous to the straight pipe portion, the first peak of the bellows pipe portion closest to the straight pipe portion and the straight pipe portion is used. A bend-shaped transition portion that connects the portions is formed. In the case of such a bent bellows hose, the length of the transition portion cannot often be increased on the side that bends in the direction close to the first peak portion or on the opposite side. For this reason, a portion where the undercut becomes strong is generated in the transition portion, making it difficult to release the mold.

  This invention is made | formed in view of such a situation, and makes it the problem which should be solved to make it easy to release from a center core, without changing the shape of the collar of a bellows pipe part.

A feature of the bellows hose of the present invention that solves the above problems is that a straight pipe portion having a fitting portion fastened to a mating member, and a central axis of a first peak closest to the straight pipe portion is a central axis of the straight pipe portion And a bellows hose comprising a bellows tube portion intersecting at an obtuse angle, and a transition portion connecting the straight tube portion and the first peak portion,
The transition part consists of an inner transition part inside the bending direction and an outer transition part outside the bending direction,
The inner peripheral surface of the inner transition portion is a curved surface having a radius of curvature (R _1), the radius of curvature (R ₁₎ is the highest portion of the inner peripheral surface of the first crest in the axial section of the bellows tube portion and the inner transition portion Greater than the distance ( h ₁ ) from the innermost surface of the inner peripheral surface of the pipe, and the thickness ( t ₁ ) of the portion continuing to the inner transition part of the straight pipe part is 60% or less of the distance ( h ₁ ), and the outer transition The radius of curvature (R ₂ ) is smaller than the distance (h ₂ ) between the top of the inner peripheral surface of the first peak and the bottom of the inner peripheral surface of the outer transition portion in the axial cross section of the bellows tube. The inner peripheral surface of the transition portion is that it is smoothly continuous with the inner peripheral surface of the first peak portion .

It is desirable that the curvature circle of the inner peripheral surface of the inner transition portion and the curvature circle of the inner peripheral surface of the first peak portion have a common tangent line and are smoothly continuous at the contact point of the tangent line.

  According to the bellows hose of the present invention, the bellows tube portion can be easily pulled out from the core without changing the shape of the flange of the bellows tube portion, that is, while maintaining the shape of the bellows tube portion with a favorable vibration resistance performance. be able to.

  When pressurizing compressed air between the inner peripheral surface of the bellows hose and the outer peripheral surface of the core, and extracting the bellows tube from the core while inflating the bellows hose, inject pressurized air into the bellows tube It is necessary that the end opposite to the side is intimately sealed with the core. Sealing the end portion in this way prevents leakage of pressurized air and expands almost the entire bellows tube portion by the pressurized air, thus enabling release from the center core.

  Here, in the case of an air cleaner hose, the straight pipe portion becomes the seal portion. However, one unit of the bellows present at the end opposite to the pressurized air injection side, that is, the first peak portion closest to the straight pipe portion among the plurality of peak portions of the bellows pipe portion is a straight pipe that is difficult to expand. Due to the presence of the part, it is easy to be caught and particularly difficult to release. Further, in the case of a bent air cleaner hose in which the central axes of the straight pipe portion and the bellows pipe portion intersect, a bent transition portion that connects the straight pipe portion and the first peak portion is formed. In particular, the undercut becomes strong at the transition portion, and release becomes difficult.

Therefore, in the bellows hose of the present invention, the inner peripheral surface of the inner transition portion is formed of a curved surface having a radius of curvature ( R ₁ ). The inner transition radius of curvature of the (R _1), the distance between the lowest portion of the inner peripheral surface of the topmost portion and the inner transition portion of the first crest inner peripheral surface of the axial section of the bellows tube portion (h ₁₎ While being larger ( h ₁ <R ₁ ), the thickness ( t ₁ ) of the portion continuing to the inner transition portion of the straight pipe portion is set to 60% or less of the distance ( h ₁ ).

With such a configuration, the inner transition portion can be easily deformed, and the first peak portion can easily get over the convex portion of the core that forms the first peak portion. Then, since a gap is generated between the inner peripheral surface of the inner transition portion and the outer peripheral surface of the core, the inner transition portion expands due to the flow of pressurized air into the gap, and the straight pipe portion is continuously accompanied accordingly. Therefore, the bellows tube portion can be easily pulled out from the center core.

The radius of curvature ( R ₁ ) of the inner transition part is less than the distance ( h ₁ ), or the wall thickness ( t ₁ ) of the straight pipe part continuous to the inner transition part exceeds 60% of the distance ( h ₁ ) In such a case, the amount of deformation of the inner transition portion when the pressurized air is introduced becomes small, and the first peak portion is caught by the convex portion of the core that forms the first peak portion, so that it is difficult to release the bellows tube portion. It becomes.

Furthermore, it is desirable that the curvature circle of the inner peripheral surface of the inner transition portion and the curvature circle of the inner peripheral surface of the first peak portion have a common tangent line and are smoothly continuous at the contact point of the tangent line. With this configuration, the amount of deformation of the inner transition portion at the time of introduction of pressurized air gradually changes, and buckling and the like are less likely to occur, so that release is further facilitated.

  Hereinafter, the present invention will be specifically described with reference to conventional examples and examples.

(Conventional example)
FIG. 2 shows a cross-sectional view of the main part of a conventional bellows hose. This bellows hose is the air cleaner hose 100 shown in FIG. 1, and includes a first straight pipe portion 101 connected to the air cleaner 200, a bellows pipe portion 102 coaxially continuous with the first straight pipe portion 101, and a bellows pipe portion. And a second straight pipe portion 103 that is coaxially connected to the engine 300 and connected to the engine 300. The air cleaner hose 100 was manufactured from synthetic rubber by injection molding.

  The first straight pipe portion 101 is continuous with the first peak portion 105 of the bellows tube portion 102 via a transition portion 104 having a curved surface with a radius of curvature (R). The radius of curvature (R) is smaller than the distance (h) between the topmost part of the inner peripheral surface of the first peak 105 and the inner peripheral surface of the first straight pipe part 101 in the axial section (h> R). Moreover, the transition part 104 shall connect the thickness of the 1st peak part 105 and the straight pipe | tube part 101 smoothly. The central axis of the first peak portion 105 intersects the central axis of the first straight pipe portion 101.

  This air cleaner hose 100 is formed by injection molding using a core 400 as shown in FIG. Then, pressurized air is injected between the air cleaner hose 100 and the core 400 from the end of the second straight pipe portion 103 after molding. Then, since the first straight pipe portion 101 and the center core 400 are tightly sealed, the bellows tube portion 102 expands. In this state, the air cleaner hose 100 is removed from the core 400 by moving the core 400 to the left in the figure and the air cleaner hose 100 to the right in the figure.

  However, in such a bent bellows hose, the length of the transition portion 104 is asymmetric with respect to the axial center, and the length of the transition portion 104 must be shortened on the inner side in the bending direction shown in an enlarged manner in FIG. Therefore, the film length is shortened, and the transition portion 104 is caught by the core 400 as shown in FIG.

Example 1
Therefore, the bellows hose of the embodiment of the present invention shown in FIG. 4 is an air cleaner hose similar to that shown in FIG. 1, and includes a first straight pipe portion 1 connected to the air cleaner, a first straight pipe portion 1 and And a bellows tube portion 2 having a continuous central axis. The bellows tube portion 2 has a plurality of peaks and valleys, and the peak portion closest to the first straight tube portion 1 constitutes the first peak portion 20. The central axis of the first straight pipe portion 1 and the central axis of the first peak portion 20 intersect at an obtuse angle as in the conventional example.

  The first straight pipe portion 1 is formed with a fitting portion 10 that is fastened to the mating member and a transition portion 11 that is continuous with the first peak portion 20. The shape of the transition portion 11 is asymmetric with respect to the axis, and an inner transition portion 12 is formed on the upper side (inner side in the bending direction) of FIG. 13 is formed.

  The outer transition portion 13 formed on the lower side (outside) of FIG. 4 has the same shape as the conventional example because there is no hindrance to the drawing. On the other hand, in the inner transition part 12, since the first peak 20 and the first straight pipe part 1 are close to each other, it is difficult to increase the length and to secure the film length.

Therefore, the inner peripheral surface of the inner transition portion 12 is a curved surface having a radius of curvature (R ₁ ) as shown in FIG. 5 and smoothly continues to the first peak portion 20 of the bellows tube portion 2. That is, as shown in FIG. 5, the curvature circle (A ₁ ) of the inner peripheral surface of the inner transition portion 12 and the curvature circle (B ₁ ) of the inner peripheral surface of the first peak portion 20 have a common tangent (L ₁ ). Also, it is smoothly continuous at the tangent point.

The radius of curvature (R ₁ ) of the inner peripheral surface of the inner transition part 12 is the distance (h) between the top of the inner peripheral surface of the first peak 20 and the bottom of the inner peripheral surface of the inner transition part 12 in the axial section. ₁ ) is larger (h ₁ <R ₁ ). Further, the wall thickness (t ₁ ) of the transition portion 12 is 60% or less of the distance (h ₁ ). Specific dimensions are R ₁ = 10 mm, h ₁ = 7.5 mm, t ₁ = 3.5 mm, and the general thickness of the bellows tube portion 2 is 3 mm.

  At the time of injection molding of the bellows hose, a center core (not shown) is used, and after the molding, a mold release step for removing the bellows hose from the core is performed. At this time, pressurized air is blown between the bellows hose and the core from the end opposite to the first straight pipe portion 1. Since the sealing function acts in a state where the first straight pipe portion 1 is in close contact with the core, and the bellows pipe portion 2 expands, the bellows hose is pulled out in the direction opposite to the first straight pipe portion 1 and the core is Pull out relatively in the opposite direction.

  At this time, since the inner transition portion 12 has the above-described shape, it can be easily elastically deformed, and the outer transition portion 13 does not hinder extraction. Therefore, the transition part 11 easily gets over the convex part which formed the 1st peak part 20 of the center on the whole periphery. Thereby, pressurized air is introduced also between the 1st straight pipe part 1 and a center core, and the 1st straight pipe part 1 expand | swells continuously, and can release a bellows hose from a center core easily. Can do.

It is a typical front view which shows the use condition of an air cleaner hose. It is principal part sectional drawing of the bellows hose of the prior art example 1. It is a principal part expanded sectional view which shows the bellows hose of the prior art example 1 at the time of mold release. It is principal part sectional drawing of the bellows hose which concerns on one Example of this invention. It is a principal part expanded sectional view of the bellows hose which concerns on one Example of this invention.

Explanation of symbols

1: First straight pipe part 2: Bellows pipe part 10: Fitting part
11: Transition part 12: Inner transition part 13: Outer transition part
20: First mountain

Claims (2)

A straight pipe part having a fitting part fastened to the mating member, a bellows pipe part in which the central axis of the first peak closest to the straight pipe part intersects the central axis of the straight pipe part at an obtuse angle, and the straight pipe part A rubber bellows hose comprising a transition portion connecting the pipe portion and the first peak portion,
The transition part is composed of an inner transition part inside the bending direction and an outer transition part outside the bending direction,
The inner peripheral surface of the inner transition portion is a curved surface having a radius of curvature (R _1), the radius of curvature (R ₁₎ is the highest portion of the inner peripheral surface of the first crest in the axial section of the bellows tube portion Is greater than the distance ( h ₁ ) between the innermost transition surface and the innermost surface of the inner transition portion, and the thickness ( t ₁ ) of the straight pipe portion continuous to the inner transition portion is equal to the distance ( h ₁ ). The outer transition portion has a radius of curvature (R ₂ ) of the innermost surface of the inner peripheral surface of the first peak portion and the outermost surface of the inner peripheral surface of the outer transition portion in the axial cross section of the bellows tube portion. A bellows hose characterized by being smaller than the distance (h ₂ ) from the bottom, and the inner peripheral surface of the inner transition portion is smoothly continuous with the inner peripheral surface of the first peak portion . 2. The bellows according to claim 1, wherein the curvature circle of the inner peripheral surface of the inner transition portion and the curvature circle of the inner peripheral surface of the first peak portion have a common tangent, and are smoothly continuous at the contact point of the tangent. hose.

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