Elastomer molded article and method for manufacturing an elastomer molded article

Abstract

Suppresses unintended deformation of the bellows section. [Solution] The elastomer molded body 10 has a bellows section 20 in which a plurality of ridges 22, 24 are connected, and is formed in a cylindrical shape. The bellows section 20 comprises a first ridge 22 and a second ridge 24 which is formed to be thicker than the first ridge 22. In the bellows section 20, the first ridge 22 has an inwardly opening recess 22a. In contrast, the second ridge 24 which is formed to be thicker than the first ridge 22 does not have an inward recess.

Description

Technical Field

[0001] This invention relates to an elastomer molded body and a method for manufacturing the elastomer molded body.

Background Art

[0002] There is a hose with bellows obtained by injection molding rubber or a thermoplastic elastomer (see, for example, Patent Document 1). In this hose, the thickness of the bellows is made thinner than the portion below the bellows, making it easier for the bellows to expand and contract or bend.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When an unintended force other than expansion and contraction or bending, such as a negative pressure inside the bellows, is applied to the bellows, the bellows may deform.

[0005] In view of the above problems in the prior art, the present invention has been proposed to preferably solve these problems, and an object thereof is to provide an elastomer molded body and a method for manufacturing the elastomer molded body that can suppress unintended deformation of the bellows.

Means for Solving the Problems

[0006] A first aspect of the elastomer molded body according to the present invention is an elastomer molded body having a bellows in which a plurality of ridges are continuous and formed in a cylindrical shape, wherein the plurality of ridges include a first ridge and a second ridge formed thicker than the first ridge.

[0007] A second embodiment of the elastomer molded article according to the present invention is, in the first embodiment, The second peak may be located at a location other than the end of the bellows section.

[0008] A third aspect of the elastomer molded article according to the present invention is, in the first or second aspect, The first mountain portion has a recess that opens inward, The second peak does not necessarily have to have an indentation on the inside.

[0009] A fourth aspect of the elastomer molded article according to the present invention is, in the first or second aspect, The recess opening inward in the second peak may be shallower than the recess opening inward in the first peak.

[0010] A fifth aspect of the elastomer molded article according to the present invention is, in the first or second aspect, The second peak may protrude outward from the first peak and have a recess that opens inward.

[0011] A sixth aspect of the elastomer molded article according to the present invention is, in any one of the first, second, third, fourth, and fifth aspects, The second peak may have injection marks of the elastomer constituting the elastomer molded body on its outer surface.

[0012] An example of a method for producing an elastomer molded article according to the present invention is: The gist of this invention is to form one of the elastomer molded articles of the first, second, third, fourth, fifth, and sixth embodiments by injecting elastomer from a gate that opens at a position corresponding to the outer surface of the second peak in the mold. [Effects of the Invention]

[0013] According to the elastomer molded article of the present invention, unintended deformation of the bellows section can be suppressed. According to the method for manufacturing an elastomer molded body according to the present invention, an elastomer molded body capable of suppressing unintentional deformation of the bellows can be obtained.

Brief Description of the Drawings

[0014] [Figure 1] It is a cross-sectional view showing an elastomer molded body according to the first embodiment. [Figure 2] It is a side view showing an elastomer molded body according to the first embodiment. [Figure 3] It is a schematic longitudinal sectional view showing a main part of a mold for molding an elastomer molded body in an open mold state. [Figure 4] It is a schematic longitudinal sectional view showing a main part of a mold for molding an elastomer molded body in a closed mold state. [Figure 5] It is a schematic cross-sectional view showing a main part of a mold for molding an elastomer molded body in a closed mold state. [Figure 6] It is a cross-sectional view showing an elastomer molded body according to the second embodiment. [Figure 7] It is a cross-sectional view showing an elastomer molded body according to the third embodiment. [Figure 8] It is a side view showing an elastomer molded body according to the third embodiment.

Modes for Carrying Out the Invention

[0015] Next, with respect to the elastomer molded body and the method for manufacturing the elastomer molded body according to the present invention, preferred embodiments will be given and described below with reference to the accompanying drawings. It should be noted that the embodiments and drawings described below are examples of a part of the embodiments of the present invention, and are not used for the purpose of limiting to these configurations, and can be appropriately changed without departing from the gist of the present invention.

[0016] (First Embodiment) The elastomer molded body 10 shown in Fig. 1 is used, for example, in an air cleaner hose that sends air purified by an air cleaner to an engine, or a grommet that protects electric wires or the like by passing electric wires or the like through it. Further, the elastomer molded body 10 may be a vehicle part, and is not limited thereto, and may be used for other parts such as home appliances. The elastomer molded body 10 is a molded product made of an elastomer. As the elastomer, for example, rubber-based materials such as ethylene-propylene-diene rubber (EPDM), and resin-based materials such as olefin-based elastomer (TPO) and styrene-based elastomer are used.

[0017] As shown in Fig. 1, the elastomer molded body 10 according to the first embodiment is a tubular body formed in a cylindrical shape with both ends open, and has an internal space 10a that communicates between both ends. The elastomer molded body 10 has a general part 12 and a bellows part 20 provided axially in the general part 12, and the bellows part 20 can be expanded and contracted and / or bent. The general part 12 is a part that does not have a bellows structure like the bellows part 20, and is composed of a cylindrical wall extending along the axial direction. Here, the axial direction refers to the direction in which the internal space 10a extends between both ends of the cylindrical elastomer molded body 10. The radial direction is a direction orthogonal to the axial direction, the inner radial side is the side toward the center of the internal space 10a, and the outer radial side is the side away from the center of the internal space 10a.

[0018] As shown in Fig. 1, the bellows part 20 is formed by a plurality of peak parts 22, 24 connected in the axial direction. The bellows part 20 includes, as the plurality of peak parts, a first peak part 22 and a second peak part 24 formed thicker than the first peak part 22. The ends of the bellows part 20 are formed by the first peak part 22, and the first peak part 22 is connected to the general part 12. In the bellows part 20, the plurality of peak parts 22, 24 are arranged at regular intervals (see Fig. 2). The bellows part 20 of the first embodiment has one second peak part 24 and two or more (eight) first peak parts 22.

[0019] As shown in Figure 1, the first peak 22 has a recess 22a that opens to the inside (internal space 10a). The first peak 22 is formed in a wave-like shape with its cylindrical wall curving radially outward and inward, and is formed with approximately the same thickness from the top to the base of the first peak 22. The first peak 22 is connected to adjacent peaks 22, 24 at their bases. The top of the first peak 22 protrudes radially outward from the outer surface of the general part 12, and the base of the first peak 22 is located radially inward from the inner surface of the general part 12.

[0020] As mentioned above, the first peak 22 has an internal recess 22a, while the second peak 24 does not have an internal recess (see Figure 1). The second peak 24 is filled with elastomer from the base to the top, connecting to the adjacent first peak 22, making the second peak 24 thicker than the first peak 22. The external shape of the second peak 24 is the same convex shape as the external shape of the first peak 22, and the radial dimension H from the base to the top of the first peak 22 and the axial dimension W between the bases are the same (see Figure 2). Thus, since the external shapes of the multiple peaks 22 and 24 of the bellows section 20 are the same, it has a good appearance. The internal shape of the second peak 24 is a flat surface connecting the inner surfaces of the bases of the adjacent first peaks 22, and the internal shapes of the second peak 24 and the first peak 22 are different. Thus, the bellows section 20 has a similar appearance to the first peak 22 and the second peak 24.

[0021] As shown in Figure 1, the second peak 24 is located at a location other than the end of the bellows section 20. More specifically, in the bellows section 20, the first peaks 22 are located on both sides of the second peak 24. The second peak 24 is used as a location for injecting elastomer when molding the elastomer molded body 10, as will be described later. In this case, the second peak 24 may be located in the axial center of the bellows section 20, as in the first embodiment, or it may be located at a location other than the center of the bellows section 20, such as a location closer to the general section 12, taking into consideration the flow of the elastomer. The second peak 24 has injection marks 26 of the elastomer constituting the elastomer molded body 10 on its outer surface (see Figure 2).

[0022] Next, the manufacturing method for the elastomer molded body 10 described above will be explained. As shown in Figure 3, the mold 30 has a lower mold 32 having a mold surface for molding the outer surface of the lower half of the elastomer molded body 10, and an upper mold 34 having a mold surface for molding the outer surface of the upper half of the elastomer molded body 10. A core 36 for molding the inner surface of the elastomer molded body 10 is set in the mold 30, and the mold 30 is closed (see Figure 4). The elastomer molded body 10 is molded by injecting elastomer into the cavity 30a of the mold 30 from a gate 38 that opens at a position corresponding to the outer surface of the second peak 24 in the mold 30 (see Figure 5). The elastomer that flows from the gate 38 to the position corresponding to the second peak 24 in the cavity 30a flows to the position corresponding to the first peak 22, and then flows through the position corresponding to the first peak 22 to the position corresponding to the general part 12, spreading throughout the entire body. Here, by positioning the gate 38 in the vertical center of the cavity 30a of the mold 30 and on the side of the cavity 30a (PL surface in this embodiment), the elastomer can be evenly distributed throughout the cavity 30a. The elastomer molded body 10 is removed from the mold 30, and the remaining runner is removed from the elastomer molded body 10 to obtain the elastomer molded body 10 as a finished product. Note that traces of runner removal appear slightly on the outer surface of the second peak 24 as injection marks 26 of the elastomer constituting the elastomer molded body 10 (see Figure 2).

[0023] In the elastomer molded body 10, the second peak 24 of the bellows section 20 is formed to be thicker than the first peak 22, resulting in higher rigidity of the second peak 24 than the first peak 22. This means that when an unintended force other than expansion / contraction or bending is applied to the bellows section 20, such as negative pressure inside the bellows section 20, the higher rigidity of the second peak 24 suppresses unintended deformation of the bellows section 20. Furthermore, in the elastomer molded body 10, only the second peak 24 is thicker than the first peak 22, while the first peak 22 is formed to be thinner. Therefore, the first peak 22 ensures the bellows function of the bellows section 20, including expansion / contraction and bending. Thus, the elastomer molded body 10 can suppress unintended deformation of the bellows section 20 while ensuring its bellows function. And, according to the manufacturing method described above, an elastomer molded body 10 capable of suppressing unintended deformation of the bellows section 20 can be easily obtained.

[0024] In the elastomer molded body 10, the first ridge 22 has an inwardly opening recess 22a, while the second ridge 24 does not have an inward recess. In this way, the elastomer molded body 10 can ensure the bellows function of the bellows section 20 with the first ridge 22, while suppressing unintended deformation of the bellows section 20 with the second ridge 24. In particular, if there is only one second ridge 24 in the bellows section 20, it is easier to ensure the bellows function of the bellows section 20.

[0025] Since unintended deformation of the bellows section 20 is more likely to occur towards the center than at the ends of the bellows section 20, the elastomer molded body 10 can more effectively suppress unintended deformation of the bellows section 20 by having the second peak 24 located at a location other than the ends of the bellows section 20.

[0026] When the elastomer is injected into the mold 30 from a position corresponding to the second peak 24 during the molding of the elastomer molded body 10, an injection mark 26 of the elastomer remains on the outer surface of the second peak 24 in the elastomer molded body 10. Here, since the second peak 24 is thicker than the first peak 22 in the bellows section 20, the position in the mold 30 corresponding to the second peak 24 is wider than the position corresponding to the first peak 22. Therefore, the flow of the elastomer is less likely to be obstructed at the position corresponding to the second peak 24, and the elastomer flows smoothly from the position corresponding to the second peak 24 to the position corresponding to the first peak 22, allowing the elastomer to spread smoothly throughout the entire area corresponding to the bellows section 20. Moreover, even when a general section 12 is formed by connecting to the bellows section 20, the elastomer can flow smoothly from the position corresponding to the bellows section 20 to the position corresponding to the general section 12, thus enabling efficient molding of the elastomer molded body 10.

[0027] For example, if elastomer is injected from one end of the bellows section 20, the elastomer has difficulty flowing at the position corresponding to the relatively thin and curved first ridge section 22, and it takes time for the elastomer to reach the other end of the bellows section 20, resulting in poor molding efficiency. Also, if elastomer is injected from both ends of the bellows section 20, molding defects such as poor air circulation and poor welds are likely to occur in the central part of the bellows section 20 where the elastomers flowing from both sides collide. As in the first embodiment, by injecting the elastomer from the position corresponding to the second ridge section 24 located in the central part of the bellows section 20, the time it takes for the elastomer to spread throughout the entire area corresponding to the bellows section 20 can be shortened, and molding efficiency can be improved. In addition, the occurrence of molding defects caused by collisions between elastomers injected from different positions can be suppressed.

[0028] (Second Embodiment) In the first embodiment, the elastomer molded body 10 does not have a recess formed on the inside of the second peak 24, but a recess 24a may be formed on the inside of the second peak 24, as shown in Figure 6 of the elastomer molded body 40 according to the second embodiment. In the description of the second embodiment, the same reference numerals as in the first embodiment are used for components similar to those in the first embodiment, and their descriptions are omitted.

[0029] As shown in Figure 6, the elastomer molded article 40 according to the second embodiment has a recess 24a in the second peak 24 that opens inward (towards the internal space 10a). The recess 24a opening inward in the second peak 24 is formed to be shallower than the recess 22a opening inward in the first peak 22. The outer shape of the second peak 24 is the same convex shape as the outer shape of the first peak 22, and the radial dimensions from the base to the top of the first peak 22 and the axial dimensions between the bases are the same. The second peak 24 has the same outer shape as the first peak 22, but because the recess 24a is shallower than the recess 22a of the first peak 22, the second peak 24 is thicker than the first peak 22. The elastomer molded article 40 according to the second embodiment can be manufactured in the same manner as the first embodiment described above.

[0030] The elastomer molded body 40 according to the second embodiment provides the same effects as the first embodiment. In addition, the elastomer molded body 40 according to the second embodiment ensures rigidity with the thick second peak portion 24, and because the second peak portion 24 has a recess 24a, it is less likely to interfere with the bellows function of the bellows portion 20.

[0031] (Third embodiment) In the first embodiment, the elastomer molded body 10 has the same external shape for the first peak 22 and the second peak 24. However, as shown in Figures 7 and 8, the elastomer molded body 50 of the third embodiment may be formed so that the second peak 24 protrudes outward more than the first peak 22. In the description of the third embodiment, components similar to those in the first embodiment are denoted by the same reference numerals as in the first embodiment, and their descriptions are omitted.

[0032] As shown in Figure 7, the elastomer molded article 50 according to the third embodiment has a second peak 24 that protrudes radially outward from the first peak 22 and has a recess 24a that opens inward (towards the internal space 10a). The recess 24a that opens inward in the second peak 24 is formed to the same depth as the recess 22a that opens inward in the first peak 22. Since the second peak 24 protrudes outward from the first peak 22, even though the recess 24a is the same as the recess 22a of the first peak 22, the second peak 24 is thicker than the first peak 22. The elastomer molded article 50 according to the third embodiment can be manufactured in the same manner as the first embodiment described above.

[0033] The elastomer molded body 50 according to the third embodiment differs from the first embodiment in that the appearance of the first peak 22 and the second peak 24 are different, but it provides the same effects and benefits as the first embodiment except for those derived from the appearance. In addition, the elastomer molded body 50 according to the third embodiment ensures rigidity with the thick second peak 24, and because the second peak 24 has a recess 24a, it is less likely to interfere with the bellows function of the bellows section 20.

[0034] (Example of change) The present invention is not limited to the aforementioned matters, but may also be applied as follows, for example. Furthermore, the present invention is not limited to the embodiments and the following specific examples of modifications. (1) In the embodiment described above, one second peak was provided, but the invention is not limited to this, and two or more second peaks may be provided. In this case, the number of second peaks should be less than the number of first peaks. (2) In the embodiment described above, a general section was provided, but the invention is not limited to this, and the general section may be omitted. (3) The elastomer molded body of the embodiment described above is formed in a cylindrical shape, but is not limited to this, and may have a polygonal cross-sectional shape such as an elliptical cross-section or a rectangular cross-section. Also, the cross-sectional shape may differ between the general part and the bellows part. (4) In the third embodiment, the second peak protrudes radially outward from the first peak and has an inwardly opening recess set to the same depth as the recess of the first peak. However, the embodiment is not limited to this, and the second peak does not have to have a recess, as in the first embodiment, and the recess of the second peak may be formed to be shallower than the recess of the first peak, as in the second embodiment. (5) In the embodiment described above, the thickness of the second peak was set to be the same over the entire circumference of the bellows section. However, the invention is not limited to this, and a portion of the circumferential area of ​​the second peak may be made thicker than the first peak. In this case, it is preferable that the location where the injection marks remain (the location of the gate during molding) is included in the portion of the second peak that is made thicker than the first peak. Furthermore, it is preferable that the portion of the second peak that is made thicker than the first peak be larger than the dimensions of the injection marks (the dimensions of the gate that opens into the cavity). Having a thickened portion in a portion of the second peak provides the reinforcement effect of the bellows section described above. (6) In the embodiments described above, the first and second peaks were formed as independent annular shapes, but the invention is not limited to this, and the first and second peaks may be connected in a spiral shape. In this case, the portion formed to be relatively thin within the spiral bellows section is called the first peak, and the portion formed to be relatively thick within the spiral bellows section is called the second peak. It is preferable that the location where the injection marks remain (the location of the gate during molding) be included in the second peak, and that the extent of the second peak be larger than the dimensions of the injection marks (the dimensions of the gate opening into the cavity). Even with a spiral bellows section, the presence of the thick second peak provides the reinforcement effect of the bellows section described above. [Explanation of Symbols]

[0035] 10, 40, 50 Elastomer molded body, 20 Bellows section, 22 First peak section, 22a Recess 24 Second peak, 24a Indentation, 26 Injection mark, 30 Molding mold, 38 Gate

Claims

1. An elastomer molded body formed in a cylindrical shape, having a bellows section with multiple connected peaks, An elastomer molded body comprising, as the plurality of peaks, a first peak and a second peak formed to be thicker than the first peak.

2. The elastomer molded article according to claim 1, wherein the second ridge portion is located at a location other than the end of the bellows portion.

3. The first mountain portion has a recess that opens inward, The elastomer molded article according to claim 1, wherein the second peak portion does not have an indentation on the inside.

4. The elastomer molded article according to claim 1, wherein the recess opening inward in the second peak is shallower than the recess opening inward in the first peak.

5. The elastomer molded article according to claim 1, wherein the second peak protrudes outward from the first peak and has a recess that opens inward.

6. The elastomer molded body according to claim 1, wherein the second peak has an injection mark of the elastomer constituting the elastomer molded body on its outer surface.

7. A method for manufacturing an elastomer molded article, comprising injecting an elastomer from a gate opening at a position corresponding to the outer surface of the second peak in the mold, thereby forming an elastomer molded article according to any one of claims 1 to 6.

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