seal

Abstract

Seal. A seal for a molding machine, the seal comprising a base having an internal socket, wherein the base is provided with a venting duct to connect the internal socket of the seal with its outer surface.

Description

Technical Field

[0001] This application relates to a seal for a molding machine. Background Technology

[0002] High-resistance foam seals (e.g., polyurethane foam seals) for single cables or wire harnesses are known to form, for example, insulating rings to create firewalls, splice overmolding, rigid wiring, or ring terminal cups. The most common way to form a seal on a cable is to inject material into a mold through which the cable or wire harness passes. The opening in the mold through which the wire harness passes must be sealed to ensure that the sealant forming the overmolded part remains within the mold during the injection process.

[0003] One of the key components in the molding process is a seal installed in the mold to ensure that the overmolding material (i.e., PUR foam) remains within the mold during the first stage of the process. Sealing the interface between the product and the mold (mold half) is known in the art through mechanical seals or resilient seals. However, these solutions do not allow for controlled venting because these seals are intended to provide a seal in the best possible way.

[0004] It is also known to provide venting channels and / or venting chambers in the mold. However, these channels and chambers may leave venting marks in the overmolded part of the final product. Summary of the Invention

[0005] The purpose of this application is to provide a seal that allows for a good seal between the mold and the product, and allows the mold to release air without leaving any air vent marks on the final product.

[0006] As a solution, this application provides a seal for a molding machine for providing a product having an overmolded part by injection molding. The seal includes a base having an internal socket for receiving the product and an outer surface, wherein the base is provided with at least one venting pipe connecting the internal socket to the outer surface of the seal.

[0007] According to this solution, proper venting is ensured during the injection molding process because the bubbly surface of the semi-liquid molding material can exit the mold through at least one venting duct of the seal. This provides a high-quality and smooth surface for the final product. Any material remaining in the at least one venting duct can be easily removed, or can remain on the outer periphery of the product in the form of a thin web and / or ring. According to this solution, the highest point in the molding machine can vent without leaving venting marks on the final product.

[0008] According to the terminology of this disclosure, injection molding includes all variations of materials injected into a mold, such as injection thermoplastic materials, hot melt materials, PUR materials, 2K PUR materials, etc.

[0009] According to one embodiment, the seal can be made of a soft foam material, including rubber materials (such as synthetic rubber or natural latex), silicone resins, polyurethane materials, or made of rubber foam or polyurethane foam. Alternatively, rigid materials such as PTFE can be used. Such seals can be manufactured in an efficient manner, can have a closed-cell structure, and can provide sufficient elasticity and resilience to seal products with different external profiles. The closed-cell structure provides very good performance in terms of elasticity.

[0010] According to another embodiment, the seal can be removably inserted into the recess of the mold. This allows the seal to be replaced to match the outer diameter of the product.

[0011] According to one embodiment, the internal socket of the substrate extends along the longitudinal axis of the seal, wherein the at least one venting conduit includes an axially extending section. In this embodiment, the at least one venting conduit includes a section extending parallel to the longitudinal axis of the seal. Since the seal surrounds the product and the overmolding material is injected into the space between the product and the mold, any gas or air bubbles will be discharged through the axially extending section of the at least one venting conduit when the overmolding material is injected into the mold. Of course, the internal socket may also have a shape such as a thread extending along the longitudinal axis.

[0012] According to another embodiment, the at least one exhaust duct includes a plurality of parallel and axially extending sections. This allows for uniform exhaust along the circumference of the product.

[0013] According to another embodiment, the at least one exhaust duct includes a radially extending section to discharge gas or bubbles without affecting the sealing properties of the seal.

[0014] According to another embodiment, these axially extending sections are merged into an annular section of the at least one exhaust duct to provide balanced exhaust.

[0015] This application also includes a molding machine for providing a product having an overmolded part by injection molding, wherein the molding machine includes a mold having a cavity for receiving the product, and wherein a seal as disclosed above is provided in the mold to seal the cavity.

[0016] The mold can be an integrated part of the molding machine, or the molding machine can be a separate station for injection.

[0017] According to one embodiment, the molding machine is configured in a working configuration such that the cavity of the mold is oriented in a vertical direction, causing gas or bubbles of the covering molding material to accumulate on top of the covering molding material between the product and the mold.

[0018] According to another embodiment, the seal is housed in a recess of the mold, wherein the mold is provided with at least one venting conduit communicating with the recess. In this embodiment, the at least one venting conduit of the mold is disposed adjacent to the seal, allowing gas to exit the mold cavity in an upward direction opposite to the direction of gravity.

[0019] According to another embodiment, the seal is housed in a recess of the mold, wherein the mold has at least one venting chamber communicating with the recess. In this arrangement, any gas or air bubbles can be expelled from the mold by forcing sufficient overmolding material into the venting chamber until no gas remains in the cavity of the mold.

[0020] This application also includes a method for providing a product having an overmolded part by injection molding in a molding machine as described above, the method comprising the steps of: inserting a seal into a recess in a mold; arranging the product in a cavity such that the seal abuts against the mold to seal the product; and injecting overmolding material into an inner container and venting the inner socket through a conduit in the seal.

[0021] In this method, a seal is used to seal the product relative to the mold to prevent the overmolding material from leaving the mold. On the other hand, the seal is also used to remove gas or air bubbles from the internal space within the mold between the product and the cavity.

[0022] According to one embodiment, the product to be sealed is at least one cable, cable bundle, cable harness, tube, or housing, etc. Attached Figure Description

[0023] An exemplary embodiment of the seal is described with reference to the accompanying drawings, in which:

[0024] Figure 1 In this context, (a)-(f) represent the individual steps of the molding process;

[0025] Figure 2 This is a side view of the seal; and

[0026] Figure 3 This is a partial view of the molding machine. Detailed Implementation

[0027] Figure 1(a)-(f) illustrate the various steps of a process for providing a product with an overmolded part by injection molding. According to an exemplary embodiment, the product is a cable 20 having an overmolded part provided with, for example, polyurethane foam material.

[0028] The molding machine used for the above process is not shown in detail, but includes a split mold with two half molds 10, wherein only one half mold (hereinafter referred to as mold) 10 is shown in the figure.

[0029] The mold 10 includes a cavity 12 for receiving the cable 20, wherein the cavity 12 is formed along a longitudinal axis A. The mold 10 also includes a pocket 14 for receiving a seal 30. The seal in each mold has a generally sleeve-shaped, separate sleeve to surround the cable 20 along half of its circumference.

[0030] Figure 2 Another embodiment of the seal 30' is shown, the seal 30' including an internal socket R for receiving the cable 20 (see Figure 1 The substrate of (b) includes an internal socket R extending along half the circumference of the cable 20. The substrate also includes an outer surface 32 extending along the outer periphery of the seal 30'. Furthermore, the substrate of the seal 30' is provided with an exhaust conduit connecting the internal socket R to the outer surface 32 of the seal.

[0031] like Figure 1 (b) and Figure 2 As shown, the internal socket R of the seals 30, 30' extends along the longitudinal axis A, and the exhaust duct disposed in the base includes multiple axially extending sections 34 incorporated into the annular section 36 of the exhaust duct. Furthermore, two radially extending sections 38, 40 are also incorporated into the annular section 40, as shown... Figure 2 As shown.

[0032] When cable 20 is inserted into the internal socket R formed by seals 30, 30', the axial extension section 34 and the annular section 36 of the exhaust duct are sealed by the outer sheath of the cable, allowing gas entering the axial extension section 34 to travel through the annular section 36 toward the radial extension section 38 to exit the seal. To allow gas to escape from the mold, mold 10 is provided with exhaust chambers 22, 24 respectively leading to the molding machine (see...). Figure 3 The exhaust chambers 22 and 24 are connected to the atmosphere via additional exhaust pipes 26 and 28.

[0033] from Figure 1 (b) to Figure 1 (e) in Figure 2A comparison shows that seals 30 and 30' have similar shapes and designs. Compared to seal 30, which can be inserted into the recess 14 of mold 10 with its top facing upwards or upside down, seal 30' needs to be inserted into the recess 14 in such a way that the axial section 34 of the exhaust pipe faces downwards.

[0034] Now refer to Figure 1 The methods for providing a sheathed part for cable 20 by injection molding in a molding machine as described above are described in (a)-(f).

[0035] Figure 1 Image (a) shows an empty mold 10 (half-mold), wherein, Figure 1 In (b), the seal 30 is inserted into the recess 14 of the cavity 12 such that the radial extension sections 38 and 40 of the venting pipe of the seal 30 are aligned with the venting pipes 16 and 18 of the mold 10.

[0036] Subsequently, cable 20 is inserted into the internal socket R of seal 30, and a second half of the mold (not shown), also provided with seal 30 in the manner described above, abuts against mold 10 to close. Seal 30 then seals cable 20 against the surrounding wall of mold 10.

[0037] exist Figure 1 In the next step shown in (d), an overmolding material 50 (e.g., PUR foam) is injected into the space between the cable 20 and the surrounding mold. During this process step, the overmolding material expands and fills the mold to form the final shape of the product. The surface of the injected overmolding material includes gas and bubbles, and the semi-liquid overmolding material is discharged through the axially extending section 34, the annular section 36, the radially extending sections 38 and 40 of the seal, and through the venting pipes 16 and 18 of the mold. Excess material is collected in the venting chambers 22 and 24. Thereafter, the space between the cable 20 and the mold 10 is completely filled with the overmolding material. After the two half-molds are opened and the cable 20 is removed, the cable is provided with an overmolded section that surrounds the outer sheath of the cable and has an annular ring on the top of the overmolded section, which is connected to the rest of the overmolded section by a plurality of axially extending webs.

[0038] Because the cable 20 is oriented vertically (parallel to the direction of gravity g) within the mold during operation, any gas within the mold will move upwards towards the seals 30, 30'. Therefore, after a certain amount of overmolding material is injected into the venting chambers 22 and 24, no gas remains within the mold. Any material remaining in the venting channels or chambers of the mold after this process can be easily removed. The material formed on the outer sheath of the cable 20 can be retained and has a flawless, attractive appearance.

Claims

1. A seal (30, 30') for a molding machine for providing a product (20) with an overmold by injection molding, the seal (30, 30') comprising: a base body having elasticity and resilience, the base body being formed of a soft foam material or a hard material and having an inner receptacle (R) for accommodating the product (20) and an outer surface (32), wherein the seal (30, 30') is configured to be accommodated within a mold having a cavity (12), wherein the seal (30, 30') is configured to provide a seal between a surrounding wall of the mold and the product, and wherein the base body is provided with at least one venting duct connecting the inner receptacle (R) with the outer surface (32) of the seal (30, 30').

2. The seal of claim 1, wherein, The inner receptacle (R) extends along a longitudinal axis (A) of the seal, and wherein the at least one venting duct further comprises an axially extending section (34).

3. The seal of claim 2, wherein, The at least one venting duct comprises a plurality of parallel and axially extending sections (34).

4. The seal of claim 3, wherein, The axially extending section (34) merges into an annular section (36) of the at least one venting duct.

5. The seal of claim 4, wherein, The at least one venting duct (34-40) comprises a radially extending section (38, 40).

6. The seal of claim 4 or 5, wherein, The annular section (36) merges into at least one radially extending section (38, 40).

7. A molding machine for providing a product with an overmold by injection molding, the molding machine comprising: a mold (10) having a cavity (12) for accommodating the product (20), wherein a seal (30, 30') according to any one of claims 1 to 6 is provided in the mold (10) to seal the cavity (12).

8. The molding machine according to claim 7, configured in a working configuration such that the cavity (12) is oriented in a vertical direction.

9. The molding machine according to claim 7 or 8, wherein, The seal (30, 30') is accommodated in a recess (14) of the mold (10), wherein the mold is provided with at least one venting duct (16, 18, 26, 28) communicating with the recess (14).

10. The molding machine of claim 7 or 8, wherein, The seal (30, 30') is accommodated in a recess (14) of the mold (10), wherein the mold is provided with at least one venting chamber (22, 24) communicating with the recess (14).

11. A method of providing a product with an overmold by injection molding in a molding machine according to any one of claims 7 to 10, the method comprising the steps of: inserting the seal into a recess of the mold; placing the product in the cavity such that the seal provides a seal between a surrounding wall of the mold and the product; injecting overmolding material into the inner receptacle and venting the inner receptacle through the venting duct of the seal.

12. The method of claim 11, wherein, The product comprises at least one electrical cable.

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