Thermoplastic elastomer bellows

Abstract

The invention relates to a thermoplastic elastomer bellows. The invention relates to a thermoplastic elastomer bellows (10) comprising a corrugated pipe section (12) between two elbow sections (14, 18), wherein at least one of the elbow sections (18) is made of thermoplastic elastomer and is connected to an end section (22) of the corrugated pipe section (12) by overmolding the elbow section (18) on the end section (22) of the corrugated pipe section (12), and wherein the end section (22) of the corrugated pipe section (12) comprises a guide and seal arrangement (50) pointing in a direction away from the corrugated pipe section (12) in a radial direction (32). The invention also relates to an air duct (80) having such a thermoplastic elastomer bellows (10).

Description

Technical Field

[0001] This invention relates to a thermoplastic elastomer corrugated duct, specifically for use in the air ducts of combustion engines. Background Technology

[0002] US2006125149A discloses a method for forming a conduit, which serves as an air duct for example, an automotive engine, and includes a corrugated section as an undercut portion in a longitudinal direction of the conduit. The method includes injecting an elastomeric material into a cavity having a cavity mold for forming an outer surface of the conduit and a core mold for forming an inner surface of the conduit, wherein the core mold is a separable core mold axially separable into two parts: one part for forming a conduit region including the corrugated section, and the other part for forming a conduit region without the corrugated section; and after opening the cavity mold, expanding the corrugated section radially by air injection to remove the conduit region including the corrugated section from the core mold.

[0003] Nevertheless, there are still some limitations regarding what geometries can be produced by this process. Summary of the Invention

[0004] The purpose of this invention is to provide a thermoplastic elastomer corrugated pipe, which includes a corrugated pipe section between two elbow-shaped sections, the two elbow-shaped sections being manufactured by two injection molding parts.

[0005] Another object of the present invention is to provide an air duct that can be manufactured from two injection-molded parts.

[0006] One object of the present invention is achieved by a thermoplastic elastomer corrugated pipe comprising a corrugated pipe section between two elbow-shaped sections, wherein at least one of the elbow-shaped sections is made of a thermoplastic elastomer and is connected to the end portion of the corrugated pipe section by overmolding the elbow-shaped section onto the end portion of the corrugated pipe section, and wherein the end portion of the corrugated pipe section includes a guiding and sealing arrangement in a radial direction pointing away from the corrugated pipe section.

[0007] Another object of the present invention is achieved by an air duct comprising a thermoplastic elastomer corrugated duct, the thermoplastic elastomer corrugated duct comprising a corrugated duct section between two elbow-shaped sections, wherein at least one of the elbow-shaped sections is made of thermoplastic elastomer and is connected to the end portion of the corrugated duct section by overmolding the elbow-shaped section onto the end portion of the corrugated duct section, and wherein the end portion of the corrugated duct section comprises a guiding and sealing arrangement in a radial direction pointing away from the corrugated duct section.

[0008] The other claims, description, and drawings depict advantageous embodiments of the invention.

[0009] According to a first aspect of the invention, a thermoplastic elastomer corrugated pipe includes a corrugated pipe section between two elbow segments, wherein at least one of the elbow segments is made of a thermoplastic elastomer and is connected to the end segment of the corrugated pipe section by overmolding the elbow segment onto an end segment of the corrugated pipe section, and wherein the end segment of the corrugated pipe section includes a guiding and sealing arrangement in a radial direction pointing away from the corrugated pipe section.

[0010] The guiding and sealing arrangement provides a function to ensure the position of the corrugated pipe section in the mold and to prevent leakage during the overmolding stage. Otherwise, due to the elasticity of the corrugated pipe section, it could have an unpredictable position in the mold.

[0011] Preferably, a thermoplastic elastomer (TPE) elbow pipe segment is overmolded onto a thermoplastic elastomer corrugated pipe segment, which is produced by an injection process and force-demolded. Preferably, a material with a Shore A hardness of 70 to 90 is used.

[0012] The overmolded connection between the corrugated pipe section and the elbow section provides excellent strength properties and meets stringent flexibility requirements for separation capabilities even without damage to the pipe.

[0013] Corrugated pipe sections can be manufactured by injection molding in a mold tool and demolded in the usual manner (e.g., force demolding). Advantageously, connecting elbow sections by overmolding allows for a variety of geometries and curvatures between the corrugated pipe sections and the elbow sections.

[0014] Advantageously, demolding of the overmolded elbow segment can be achieved without specialized tools such as pressurized air injection. It can be manufactured using one injection mold or two molds.

[0015] The guiding and sealing arrangement can utilize one or more features on the corrugated pipe section to provide guiding and sealing functions. Features serving as sealing functions are advantageously arranged continuously around the corrugated pipe section. Features serving as guiding functions preferably have at least a surface capable of guiding a slider to its correct position. Specifically, this feature may have an inclination to allow an external slider to guide this section to the correct position. Simultaneously, the corrugated pipe section is positioned in a stable position. This feature may be continuously arranged around the corrugated pipe section, or divided into several sections, or only in a small section.

[0016] The corrugated pipe section can be integrally manufactured with the first elbow section in an injection mold. Optionally, the corrugated pipe can be manufactured with elbow sections attached to the two end sections of the corrugated pipe section by overmolding.

[0017] According to an advantageous embodiment of the corrugated pipe, the guiding and sealing arrangement may include at least one continuous rib projecting radially from the outer surface of the end section. Despite the high pressure during injection molding, the continuous rib still allows for a reliable seal. The ribs provide the intended functions on their respective sides, with guiding functionality on one side and sealing functionality on the opposite side.

[0018] According to an advantageous embodiment of the corrugated pipe, the continuous ribs have a tapered cross-section. Each side of the rib can be optimized for a desired function, wherein a guiding function is provided on one side of the rib and a sealing function is provided on the opposite side of the rib. Advantageously, the side configured for sealing can be inclined at an angle of at least 5° and no more than 45°. Similarly, the side configured for guiding can be inclined at an angle of at least 5° and no more than 45°. Advantageously, the sealing side can intersect the outer surface of the end section at a steeper angle compared to the guiding side.

[0019] According to an advantageous embodiment of the corrugated pipe, the continuous rib may include a sealing side and an opposing guiding side, specifically wherein the sealing side intersects the wall at a steeper angle than the guiding side. Specifically, the sealing side of the rib may be arranged closer to the end segment than the opposing guiding side. When material is introduced by injection during molding, the sealing function can be ensured by a slider with appropriate recesses in the mold.

[0020] Specifically, the sealing side of the rib can be arranged closer to the end segment than the opposing guide side. Advantageously, the sealing side can point towards the elbow segment, where the guide side is the opposite side of the rib. In an advantageous embodiment, the sealing side of the rib can be arranged perpendicular to or at a small angle of less than 10° to the outer surface perpendicular to the end segment.

[0021] According to an advantageous alternative embodiment of the corrugated pipe, the guiding and sealing arrangement may include a first rib structure configured to guide the injection tool when it is closed around an end section of the corrugated pipe segment; and a second rib structure configured to overcome pressure to seal the injection tool during overmolding on the end section of the corrugated pipe segment. Advantageously, the sealing rib structure can be optimized for the sealing function independently of the guiding function, and vice versa.

[0022] According to an advantageous embodiment of the corrugated pipe, the guide rib structure and the sealing rib structure can be configured as continuous ribs on the outer surface of the end section. This arrangement has a simple and reproducible geometry.

[0023] According to an advantageous embodiment of the corrugated pipe, on the outer surface of the end section, the sealing rib structure can be configured as a continuous rib and the guide rib structure can be configured as a discontinuous array of ribs. Those skilled in the art can select from different arrangements according to the desired layout.

[0024] According to an advantageous embodiment of the corrugated pipe, the guide rib structure and the sealing rib structure can be arranged symmetrically with respect to the inclination of the specific rib surfaces. This arrangement has a simple and reproducible geometry.

[0025] According to an advantageous embodiment of the corrugated pipe, the guide and sealing arrangement may protrude from the outer surface of the wall of the end section by a distance equal to at least 1 / 4, specifically at least 1 / 3, of the wall thickness at the intersection of the guide and sealing arrangement and the wall on the distal side in front. Specifically, the ribs or rib arrays arranged on the distal side of the end section may protrude by a distance equal to at least 1 / 4, specifically at least 1 / 3, of the wall thickness at the intersection between the end section and the side of the ribs or rib array opposite to the end section.

[0026] According to an advantageous embodiment of the corrugated pipe, the sealing rib structure can be arranged closer to the end section than the guide rib structure. This arrangement is advantageous for sealing in the mold.

[0027] According to another aspect of corrugated ducts, an air duct is proposed, comprising a thermoplastic elastomer corrugated duct including a corrugated duct section between two elbow-shaped sections, wherein at least one of the elbow-shaped sections is made of thermoplastic elastomer and is connected to the end portion of the corrugated duct section by overmolding the elbow-shaped section onto the end portion of the corrugated duct section, and wherein the end portion of the corrugated duct section includes a guiding and sealing arrangement in a radial direction pointing away from the corrugated duct section.

[0028] Advantageously, this provides a reliable and cost-effective technical solution for flexible corrugated ducts. Nevertheless, the air duct still offers sufficient material flexibility and strength. The overmolded connection between the corrugated and elbow sections provides excellent strength properties and meets stringent flexibility requirements for separation capabilities even without damage to the ductwork. Attached Figure Description

[0029] The invention, together with the foregoing and other objects and advantages, can be best understood from the following detailed description of the embodiments, but is not limited to these embodiments, wherein:

[0030] Figure 1 A perspective view of an air duct according to an embodiment of the present invention is shown, the air duct comprising a corrugated duct section disposed between two elbow-shaped sections;

[0031] Figure 2 It shows according to Figure 1 A perspective view of a corrugated pipe segment, wherein the corrugated pipe segment has an elbow-shaped pipe and an end section for covering a molded second elbow-shaped segment;

[0032] Figure 3 The side view shows details of a guide and seal arrangement located at the end section of a corrugated pipe segment according to an embodiment of the invention, wherein the guide and seal arrangement includes a circumferential rib having a guide and seal function;

[0033] Figure 4 The cut view shows the data based on... Figure 3 Details of the interface between the corrugated pipe section and the overmolded section;

[0034] Figure 5 The longitudinal sectional view shows details of a guide and sealing arrangement consisting of a single rib according to an embodiment of the invention;

[0035] Figure 6 The side view shows details of a guide and sealing arrangement positioned at the end section of a corrugated pipe section according to an embodiment of the invention, wherein the guide and sealing arrangement includes two circumferential ribs having a sealing rib structure and a guide rib structure.

[0036] Figure 7 The sectional view shows the data according to... Figure 6 Details of the interface between the corrugated pipe section and the overmolded section;

[0037] Figure 8The perspective longitudinal section view shows details of the interface at the end section of the corrugated pipe segment, which is partially enclosed by the slider of the mold, wherein the elbow core is inserted into the corrugated pipe segment at the end section.

[0038] Figure 9 The longitudinal sectional view shows the data according to... Figure 8 The interface between the slider and the core;

[0039] Figure 10 The longitudinal sectional view shows the data according to... Figure 8 The interface between the slider and the core, indicating the sealing ribs on the slider and the core;

[0040] Figure 11-16 The different stages of the injection process for covering a molded elbow segment onto a corrugated pipe segment are shown. Detailed Implementation

[0041] In the accompanying drawings, the same elements are referenced by equivalent reference numerals. The drawings are merely schematic and are not intended to depict specific parameters of the invention. Furthermore, the drawings are intended to depict only typical embodiments of the invention and should therefore not be considered as limiting the scope of the invention.

[0042] Figure 1 The perspective view depicts an air duct 80 including a thermoplastic elastomer corrugated duct 10. The thermoplastic elastomer corrugated duct 10 includes a corrugated duct section 12 located between two elbow sections 14, 18. In this embodiment, the corrugated duct section 12 and the first elbow section 14 are integrally formed to create the basic duct body 40.

[0043] Air duct 80 may include one or more additional ducts (not shown) attached to duct body 40. Figure 2 The basic pipeline body 40 is shown in isolation.

[0044] The corrugated pipe section 12 has a corrugated portion, with a first elbow section 14 at one end. The first elbow section 14 has a curved region 16 juxtaposed to the corrugated portion of the corrugated pipe section 12.

[0045] On the opposite side of the corrugated portion of the corrugated pipe section 12, a straight pipe portion having an end section 22 is arranged, and a second elbow-shaped portion 18 is attached to the end section 22 by overmolding. The second elbow-shaped portion 18 has a curved region 20 that is juxtaposed to the end section 22 at the straight portion of the corrugated pipe section 12. In another embodiment, the corrugated pipe does not terminate in a straight line, but has an end with another shape, such as a curved section.

[0046] The end segment 22 is provided with a guide and seal arrangement 50, which is formed as a single external rib 54 that extends continuously along the circumference of the end segment 22.

[0047] Preferably, all sections of the corrugated pipe 10 are made of thermoplastic elastomer materials, such as, for example, polyamide elastomers, polyester elastomers, polyurethane elastomers (e.g., polyester-urethane elastomers and polyether-urethane elastomers), polystyrene elastomers, polyolefin elastomers (e.g., elastomers comprising polyethylene or polypropylene as hard segments and ethylene propylene rubber or ethylene-propylene-diene rubber as soft segments; olefin elastomers comprising hard and soft segments with different degrees of crystallinity), polyvinyl chloride elastomers, fluorinated thermoplastic elastomers, etc. These thermoplastic elastomers can be used alone or in combination.

[0048] Figure 3 The side view shows details of a guide and seal arrangement 50 located at the end section 22 of a corrugated pipe section 12 according to an embodiment of the invention, wherein the guide and seal arrangement 50 includes a continuous circumferential rib 54 that provides guide and seal functions.

[0049] Figure 4 The sectional view shows the data according to... Figure 3 Details of the interface 78 between the corrugated pipe section 12 and the elbow-shaped section 18 molded on the end section 22 of the corrugated pipe section 12.

[0050] In this embodiment, the guiding and sealing arrangement 50 includes a continuous rib 54 projecting radially 32 from the outer surface 26 of the end segment 22.

[0051] The continuous rib 54 has a tapered cross-section. The continuous rib 54 includes a rib surface 56 having a sealing side 56 and an opposing guiding side 58. Specifically, the sealing side 56 intersects the wall at a steeper angle than the guiding side, pointing toward the elbow segment 18. The rib surface 56 is arranged perpendicular to or nearly perpendicular to the outer surface 26 of the end segment 22.

[0052] The rib surface 56 of rib 54 pointing towards elbow segment 18 is the sealing side 56 of rib 54, and the opposite rib surface 58 is the guiding side 58 of rib 54. The guiding side 58 allows for ensuring that the corrugated pipe segment 12 is correctly positioned in the mold before overmolding. The sealing side 56 helps to prevent leakage during the overmolding stage.

[0053] The elbow segment 18 extends into a protrusion 19 of material on the sealing side 56 of the rib 54.

[0054] Optionally, the front end 36 of the end segment 22 may be provided with serrations or lobes (not shown) extending in the axial direction 30 to improve the connection between the end segment 22 and the elbow segment 18 at the interface 78.

[0055] Figure 5 The longitudinal sectional view shows details of a guide and seal arrangement 50 at the end section 22 of the corrugated pipe section 12 according to an embodiment of the invention, the guide and seal arrangement 50 consisting of a rib 54.

[0056] Rib 54 has a tapered cross-section, wherein the sealing side 56 is inclined at an angle σ between the face of the sealing side 56 and the radial direction 32, the angle being at least 5° and no greater than 45°. Guide side 58 is inclined at an angle γ between the face of the guide side 58 and the radial direction 32, the angle being at least 5° and no greater than 45°. In one embodiment, angle σ may be much smaller than angle γ.

[0057] The wall 24 of the end section 22 has a thickness 34 at the intersection of the rib 54 (specifically, the guide side 58 of the rib 54) and the outer surface 26 of the corrugated pipe section 12.

[0058] The height 76 of the rib 54 in the radial direction 32 is at least 1 / 4, preferably 1 / 3, of the thickness 34 of the wall 24.

[0059] The wall 24 can be thinner on the opposite side 56 of the rib 54 because the material from the overmolded elbow segment 18 will increase the total thickness at the interface 78.

[0060] Figure 6 The side view shows details of an alternative guide and seal arrangement 50 located at the end section 22 of a corrugated pipe section 12 according to another embodiment of the invention, wherein the guide and seal arrangement 50 includes two circumferential ribs configured as a guide rib structure 60 and a seal rib structure 70.

[0061] Figure 7 The sectional view shows the data according to... Figure 6 Details of the interface 78 between the corrugated pipe section 12 and the overmolded section 18.

[0062] The guide rib structure 60 is configured to guide the slider when it closes the injection mold around the end section 22 of the corrugated pipe section 12, so that the corrugated pipe section is correctly positioned in the mold. The sealing rib structure 70 is configured to overcome pressure and seal the injection tool during overmolding on the end section 22 of the corrugated pipe section 12.

[0063] The sealing rib structure 70 and the guide rib structure 60 are configured as continuous ribs on the outer surface 26 of the end section 22.

[0064] The sealing rib structure 70 is arranged closer to the front 36 of the corrugated pipe section 12 than the guide rib structure 60.

[0065] In this embodiment, the guide rib structure 60 and the sealing rib structure 70 are arranged symmetrically with respect to the inclinations of the specific rib surfaces 72, 62 and 74, 64. The rib structures 60, 70 enclose the groove 52, where the wall 24 is thinner than at the distal side of the guide and sealing arrangement 50.

[0066] In an alternative embodiment (not shown), the sealing rib structure 70 may be configured as a continuous rib and the guide rib structure 60 may be configured as a discontinuous rib array on the outer surface 26 of the end segment 22.

[0067] In an alternative embodiment, the guide rib structure 60 may be configured with even only one protrusion instead of multiple ribs.

[0068] Figure 8 The perspective longitudinal sectional view depicts details of the interface at the end section 22 of the corrugated pipe section 12, which is partially enclosed by a laterally separable slider 110 of the mold and has an elbow-shaped core 120 inserted into the corrugated pipe section 12 at the end section 22. Figure 9 The longitudinal sectional view shows the data according to... Figure 8 The interface between the detachable slider 110, the corrugated pipe section 12, and the core 120. Figure 10 These interfaces are shown in the enhanced view.

[0069] Figure 8 The bold arrows in the text indicate the demolding direction of the slider 110 and the elbow core 120.

[0070] As in Figure 9 As best seen in the enhanced view, rib 114 protrudes from the surface of the removable slider 110 into the corrugated pipe section 12. Similarly, rib 122 protrudes from the surface of the elbow core 120 into the corrugated pipe section 12. Ribs 54 of the guide and sealing arrangement 50 are engaged in the recess 112 of the removable slider 110.

[0071] Ribs 114 and 122 press against the wall 24 of the corrugated pipe section 12 from both the inside and outside to prevent leakage and improve mold closure.

[0072] It should be understood that, additionally or alternatively, such ribs can be arranged on the inner and / or outer surfaces of the corrugated pipe section 12.

[0073] Figures 11 to 16Different stages of the injection process for covering the molded elbow segment 18 onto a base pipe body 40 are illustrated, wherein the base pipe body 40 includes a corrugated pipe segment 12 and an elbow segment 14. In this embodiment, two molds 100 and 130 are used.

[0074] Figure 11 A mold 100 is shown having two detachable sliders 102, 104 for manufacturing the base pipe body 40, wherein the corrugated portion of the corrugated pipe section 12 is in slider 104 and the elbow section 14 is in slider 102.

[0075] Figure 12 The demolding of the base pipe body 40 is shown. The detachable slider 104 is removed from the corrugated portion of the corrugated pipe section 12, and the corrugated core 106 is forcefully demolded from the corrugated pipe section 12. The elbow section 14 remains in the slider 102, as shown in... Figure 13 As can be seen from it.

[0076] At the end section 22 of the corrugated pipe section 12, a guiding and sealing arrangement 50 has been formed by combining it with the basic pipe body 40.

[0077] The end section 22 of the basic pipe body 40 can now be used for a laterally detachable slider 110 arranged around the end section 22, as in Figure 14 As illustrated in the exploded view.

[0078] At the end section 22, the elbow-shaped core 120 is inserted through the opening of the corrugated pipe section 12 and closes the detachable slider 116. During this process, the corrugated portion of the corrugated pipe section 12 is slightly compressed because the geometry of the corrugated pipe is variable and due to the force in the mold 100 during the demolding process. Figure 12 The final shape of the bellows is uncertain.

[0079] Figure 14 The bold arrows in the text indicate the closing direction of sliders 110, 116 and core 120.

[0080] The slider 110 engages the guide and sealing arrangement 50 and guides the corrugated pipe section 12 into the correct position, and the removable slider 110 can close properly. Similarly, the slider 110 provides a seal with the guide and sealing arrangement 50 to prevent leakage during molding.

[0081] When slider 110 is closed, slider 116 can be closed by abutting against elbow core 120.

[0082] Figure 15 The mold 130 is shown in a closed configuration, ready for the overmolding step.

[0083] Figure 16 The exploded view of mold 130 illustrates the end of the overmolding process, wherein the complete corrugated pipe 10 is characterized by a guide and sealing arrangement 50 between the corrugated pipe section 12 and the overmolded elbow section 18.

Claims

1. A thermoplastic elastomer corrugated pipe (10) comprising a corrugated pipe section (12) between two elbow-shaped sections (14, 18), wherein, At least one of the elbow segments (18) is made of thermoplastic elastomer and is connected to the end segment (22) of the corrugated pipe segment (12) by overmolding the elbow segment (18) onto the end segment (22) of the corrugated pipe segment (12), and wherein the end segment (22) of the corrugated pipe segment (12) includes a guiding and sealing arrangement (50) pointing in a radial direction (32) away from the corrugated pipe segment (12). The guiding and sealing arrangement (50) includes at least one continuous rib (54) projecting radially (32) from the outer surface (26) of the end segment (22), the continuous rib (54) including a sealing side (56) pointing toward the elbow segment and an opposing guiding side (58) pointing away from the elbow segment, wherein the sealing side (56) intersects the wall at a steeper angle than the guiding side (58), the guiding side (58) allows ensuring that the corrugated pipe segment (12) is correctly positioned in the mold before overmolding, and the sealing side (56) helps to prevent leakage during the overmolding stage.

2. The corrugated pipe according to claim 1, wherein, The continuous rib (54) has a tapered cross-section.

3. The corrugated pipe according to claim 1, wherein, The sealing side (56) of the continuous rib (54) is arranged closer to the end segment (22) than the opposite guide side (58).

4. A thermoplastic elastomer corrugated pipe (10) comprising a corrugated pipe section (12) between two elbow-shaped sections (14, 18), wherein, At least one of the elbow segments (18) is made of a thermoplastic elastomer and is connected to the end segment (22) of the corrugated pipe segment (12) by overmolding the elbow segment (18) onto the end segment (22) of the corrugated pipe segment (12), and wherein the end segment (22) of the corrugated pipe segment (12) includes a guiding and sealing arrangement (50) pointing in a radial direction (32) away from the corrugated pipe segment (12), wherein the guiding and sealing arrangement (50) includes: a guiding rib structure (60) configured for surrounding The end section (22) of the corrugated pipe segment (12) guides the injection tool when it closes; and a sealing rib structure (70) configured to overcome pressure and seal the injection tool during overmolding on the end section (22) of the corrugated pipe segment (12), the sealing rib structure (70) including a sealing rib surface (72) pointing toward the elbow section, and a guide rib structure (60) including a guide rib surface (62) pointing away from the elbow section, wherein the sealing rib structure (70) is arranged closer to the end section (22) than the guide rib structure (60).

5. The corrugated pipe according to claim 4, wherein, The guide rib structure (60) and the sealing rib structure (70) are configured as continuous ribs on the outer surface (26) of the end section (22).

6. The corrugated pipe according to claim 4, wherein, On the outer surface (26) of the end section (22), the sealing rib structure (70) is configured as a continuous rib and the guide rib structure (60) is configured as a discontinuous rib array.

7. The corrugated pipe according to any one of claims 4 to 6, wherein, The distance by which the guide and sealing arrangement (50) protrudes from the outer surface (26) of the wall (24) of the end section (22) is at least 1 / 4 of the wall thickness (34) at the intersection of the guide and sealing arrangement (50) and the wall (24) on the side away from the front (36).

8. An air duct (80) comprising a corrugated duct (10) according to any one of the preceding claims.

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