KR102112038B1 - Insert injection molding of oil seal for gear cover and insert injection modling method using the same - Google Patents

Abstract

In the mold for injection molding of an oil seal for a gear cover using a thermoplastic elastomer and an injection method using the same, the mold for injection molding of an oil seal for a gear cover using a thermoplastic elastomer is for producing an oil seal for a gear box composed of a support part and an oil seal part. In the insert injection mold, the first mold having a circular seating surface on which the rear surface of the support portion is seated is coupled to the first mold and the first mold, and a circular core portion on which the front surface of the support portion is seated is formed in the central portion. And a second mold in which a thermoplastic elastomer is injected into a space between the first mold and through the resin injection holes formed in the core portion to form the oil seal.

Description

Mold for injection molding of oil seals for gear covers using thermoplastic elastomers and insert injection methods using the same. {INSERT INJECTION MOLDING OF OIL SEAL FOR GEAR COVER AND INSERT INJECTION MODLING METHOD USING THE SAME}

The present invention relates to an insert injection mold of an oil seal for a gear cover and an injection method using the same, and more particularly, to an insert injection mold of an oil seal for a gear cover using a thermoplastic elastomer (TPE) composition and an insert injection method using the same. .

Oil seals for gearboxes are used to prevent leakage in gearboxes of geared motors used to drive windows or sunroofs in vehicles.

1 is a block diagram showing a conventional oil seal 1 for a gear box, and FIG. 2 is a view showing a manufacturing process of the oil seal part of the oil seal 1 for a gear box in FIG. 1.

In general, the oil seal for the gear box, as shown in Figure 1, the oil seal (부) for preventing oil leakage (2) and the support (支持) for pressing and supporting the oil seal (2) in the axial direction (支持) It consists of 3). In this case, the oil-proof part 2 may include a vulcanized rubber (NBR, Nitrile-butadiene rubber) material, and the support part 3 may include a polybutylene terephthalate (PBT) material.

That is, the oil seal 1 for the gear cover currently used is composed of the oil-proof part 2 of vulcanized rubber (NBR) material and the support part 3 of injection-molded PBT material, and the oil-proof part 2 is NBR. It is made by injection molding by vulcanization / compression molding.

However, the oil seal 1 for the gear cover has a low dimensional accuracy, and assembling failure occurs due to a manual assembly process with the support part. It is outside the scope of 3R (Reuse, Remanufacturing, Recycling).

In addition, in general, the injection molding for securing the support is simple, but the manufacturing process for forming the oil seal is much complicated and relatively complicated as shown in FIG. 2. Looking at the specific process, the material weight to match the ratio of raw materials to secure the rubber properties, the mixing / mixing process of the raw materials, the physical property test to determine whether the characteristics are secured, the aging step to secure stable properties, the NBR version Until the cutting process to cut to a size suitable for molding, it is necessary to go through a very complicated and long process even when preparing the material, which is a step prior to compression molding, and even after molding, a finishing process to cut off the part that is out of the mold must be added.

Due to the complex process described above, various process problems and vulnerabilities occur. There is a high possibility of defects in the raw material itself due to inaccurate material weight, non-uniform mixing / kneading, and inadequate aging environment, and over cure or under cure (Under) due to immature vulcanization (compression molding). cure) is not only likely to cause defects, but also in the vulcanization operation, the amount of NBR input may increase, and the amount of work in the finishing process may increase. In addition, since NBR is fixed inside the mold, the continuity of mold use is poor, and defects can occur frequently due to post-deformation due to heat of the support part inserted into the mold, and flows when the reference type / inside is 8 due to support (PBT) and rubber extrusion Since it has an influence on gender (deficient), it is expected that 6 to 8 additional injection gates are required at the PBT and rubber protrusions, so that an increase in weight is expected, thereby increasing the mold cost of the PBT / rubber mold due to shape difficulty.

On the other hand, the environmentally friendly thermoplastic elastomer (TPE) is a material that simultaneously expresses the elasticity of rubber and the excellent processability of a thermoplastic plastic resin, and has a low specific gravity and does not require a vulcanization process, and is a material that is lightweight and easy to recycle for improving fuel efficiency. In addition, it is a block polymer with elasticity in a specific temperature range, or a composite composed of a binary component constituting a hard segment and a soft segment. It is a source material capable of various molding processes by physical cross-linking from secondary intermolecular forces. Because of this, it is spotlighted as a new replacement material for rubber materials that require excellent physical properties.

In addition, the environment-friendly thermoplastic elastomer is a material that exhibits excellent resilience with high strain, and is widely used as tires, various automobile parts that require precision, industrial parts, sports goods, medical supplies, leisure, toys, and plastic modifiers. It is used, and the demand for new environmentally friendly elastic materials that can reduce the environmental load along with the improvement of performance is increasing significantly.

As a lightweight material that has the advantages of excellent processability and recyclability of thermoplastic resins and elasticity of vulcanized rubber, the scope of application is rapidly expanding in all industries and is emerging as a new material that can completely replace vulcanized rubber in the future.

Republic of Korea Registered Patent No. 10-1561243 Republic of Korea Patent Publication No. 10-2016-0076029

Thus, the technical problem of the present invention was conceived in this regard, and the object of the present invention is to manufacture the oil-proof part of an oil seal for a gear cover by insert injection molding using a thermoplastic elastomer (TPE), thereby providing a conventional product. It relates to a mold for injection molding of an oil seal for a gear cover using a thermoplastic elastomer capable of fundamentally removing or minimizing defects and process problems, and further implementing an eco-friendly production of an oil seal insert for a gear cover.

In addition, another object of the present invention relates to an insert injection method using a mold for insert injection of an oil seal for a gear cover using a thermoplastic elastomer.

The insert injection mold of the oil seal for a gear cover using a thermoplastic elastomer according to an embodiment for realizing the object of the present invention described above is in an insert injection mold for manufacturing an oil seal for a gear box composed of a support part and an oil seal part. , A first mold having a circular seating surface on which a rear surface of the support portion is seated is coupled to the first mold, and a circular core portion on which a front surface of the support portion is seated is formed in the central portion, and formed on the core portion And a second mold in which a thermoplastic elastomer is injected into the space between the first mold through the resin injection holes to form the oil seal.

In one embodiment, a first groove recessed in a ring shape along an outer surface of the seating surface is formed on one surface of the first mold, and an outer surface of the core part on a surface facing the first mold of the second mold A second groove recessed in the shape of a ring may be formed.

In one embodiment, an air discharge unit communicating with the first groove to form a concave groove shape and discharging air between the first and second molds is formed on one surface of the first mold, and the second mold An air discharge portion formed to face the first mold and to form a concave groove in communication with the second groove and facing the air discharge portion may be formed.

In one embodiment, when the first and second molds are coupled while the support is seated therebetween, the rear and front surfaces of the guide wall formed along the circumference in the support are respectively in the first and second grooves, respectively. Can be inserted.

In one embodiment, the resin injection holes may be formed in an axisymmetric shape at regular intervals in the core portion.

In one embodiment, the seating surface may be formed with a plurality of ejection holes through which air is injected or through which ejection pins are axially symmetrical.

In one embodiment, first faces of a protruding shape are formed at each corner of one surface of the first mold, and each of the first faces is provided at each corner of the face facing the first mold of the second mold. Depressed second surfaces are formed to be coupled with, and a fastener having an open shape may be formed on each of the second surfaces.

In one embodiment, it is installed adjacent to the second mold, may further include a heating unit for applying heat to the thermoplastic elastomer passing through the resin injection port.

In an insert injection method using an insert injection mold of an oil seal for a gear cover using the thermoplastic elastomer according to an embodiment for realizing another object of the present invention described above, manufacturing an oil seal for a gear box composed of a support part and an oil seal part In the insert injection method, the support portion is seated on the seating surface of the first mold. A second mold is combined with the first mold. The oil seal for the gear cover is produced by injecting a thermoplastic elastomer into the rear and hollow portions of the support to form an oil seal. After separating the second mold from the first mold, the oil seal for the gear cover is taken out from the second mold.

According to embodiments of the present invention, the support is inserted into the insert between the first and second molds, a thermoplastic elastomer (Thermo Plastic Elastomer) that does not require a complicated preparation step such as basis weight, mixing / kneading, aging on the support , TPE) by injecting material, it is possible to produce high quality products with minimal defects by reducing process steps and increasing stability.

In particular, by using only a single material, TPE, as a material injected between the first and second molds, it is possible to reduce the defect rate of the oil seal through material simplification and minimize the hardness defect, and furthermore, recycling of the TPE material is possible. It is possible to improve the eco-friendliness.

In addition, since the melted TPE is injected into the support portion seated between the first and second molds to form an oil-proof portion, close clamping between the support portion and the oil-proof portion is possible, thereby eliminating assembly defects, thereby improving dimensional accuracy and assembly. It can be improved, and the process of material preparation, measurement, aging, cutting, etc. in the prior art can be omitted, so that high-speed processing, which is a characteristic of injection molding, is possible, thereby improving production speed and productivity.

1 is a block diagram showing a conventional oil seal for a gear box.
Figure 2 is a process diagram showing the manufacturing process of the oil seal of the oil seal for the gear box of Figure 1;
3A and 3B are schematic views showing an oil seal manufactured using insert injection according to an embodiment of the present invention.
4 is an image showing a first mold used for insert injection according to an embodiment of the present invention.
5 is an image showing a second mold coupled to the first mold of FIG. 4.
6 is a flowchart illustrating an insert injection method using the insert injection molds of FIGS. 4 and 5.
7A to 7D are process diagrams showing the insert injection method of FIG. 6.

The present invention can be applied to various changes and can have various forms, and the embodiments are described in detail in the text. However, this is not intended to limit the present invention to a specific disclosure form, and it should be understood as including all modifications, equivalents, and substitutes included in the spirit and scope of the present invention. In describing each drawing, similar reference numerals are used for similar components. Terms such as first and second may be used to describe various components, but the components should not be limited by the terms.

The terms are used only for the purpose of distinguishing one component from other components. The terms used in the present application are only used to describe specific embodiments, and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise.

In this application, terms such as “comprise” or “consist of” are intended to indicate that a feature, number, step, operation, component, part, or combination thereof described in the specification exists, and that one or more other features are present. It should be understood that the existence or addition possibilities of fields or numbers, steps, actions, components, parts or combinations thereof are not excluded in advance.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by a person skilled in the art to which the present invention pertains. Terms such as those defined in a commonly used dictionary should be interpreted as having meanings consistent with meanings in the context of related technologies, and should not be interpreted as ideal or excessively formal meanings unless explicitly defined in the present application. Does not.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

3A and 3B are schematic views showing an oil seal manufactured using insert injection according to an embodiment of the present invention. 4 is an image showing a first mold used for insert injection according to an embodiment of the present invention. 5 is an image showing a second mold coupled to the first mold of FIG. 4.

3A and 3B, an oil seal 5 for a gear cover may be manufactured using a mold 10 for insert injection according to this embodiment (see FIG. 7A), in which case the oil seal for the gear cover 5 ) Is formed in the form of a ring as a whole and is divided into two parts: a support portion 20 (see FIG. 7A) and an oil seal portion 30 (see FIG. 7A).

Here, the support part 20 should be prepared and prepared in advance by an injection molding method, and the oil seal part 30 is seated between the first and second molds 100 and 200 described below by the support part 20. It is formed while the thermoplastic elastomer is cured by injecting a thermoplastic elastomer in a dried state.

Here, the support portion 20 serves as a frame of the oil seal for the gear cover, and is generally made of a rigid material capable of maintaining shape, but the material is not limited to a specific type. However, the support portion 20 is also manufactured in advance through injection molding, and may be formed of a plastic material suitable for injection molding.

In general, when the oil seal is worn by a long-term operation or air bubbles are formed inside the oil seal, an oil seal may not function and an oil leak may occur. It serves to prevent leakage.

The oil-proof part 30 is the hollow portion 40 of the support part 20 as the thermoplastic elastomer is injected into the hollow part 40 of the support part 20 and the rear face 50 of the support part 20, and It is formed in a form surrounding the rear surface 50 of the support 20.

In other words, the rear surface of the support portion 20 is in close contact with the first mold 100 of the insert injection mold 10 (see FIG. 4), and the front surface of the support portion 20 is When the thermoplastic elastomer is injected between the first and second molds 100 and 200 in a state in close contact with the second mold 200 (see FIG. 5) of the insert injection mold 10, the thermoplastic elastomer It is cured to cover the hollow portion 40 of the support portion 20 and the rear surface 50 of the support portion 20 to form an oil-proof portion 30.

As described above, the oil seal 5 for the gear cover composed of the oil seal part 30 and the support part 20 forms a shape as shown in FIG. 3A, and the front face 21 This forms a shape as shown in Figure 3b.

In this case, since the front surface of the support part 20 is not covered by the oil seal part 30, it forms the same shape as the front surface of the oil seal 5 for the gear cover.

As shown in FIG. 3B, the support part 20 is formed with a guide wall 24 along a circumference, and a ring shape is formed in a space between the hollow part 40 of the support part 20 and the guide wall 24. A resin seating surface 25 having a groove shape is formed.

On the other hand, since the rear surface of the support part 20 is a form in which a part of the support part 20, that is, the back surface of the resin seating surface 25 is covered, the support part 20 is the guide walls in FIG. 3B. Only 24 and the hollow 40 are shown.

Referring again to FIGS. 4 and 5, the insert injection mold 10 includes the first mold 100 and the second mold 200.

In this case, the oil seal part 30 is thermoplastic between the first and second molds 100 and 200 while the support part 20 is positioned between the first and second molds 100 and 200. The elastomer is injected and molded into a solid form, and is formed to be integrated with the support 20.

As described above, since the oil seal part 30 is integrated with the support part 20 through injection molding, a separate assembly process is not required when the oil seal part 30 and the support part 20 are combined. Since it is not necessary, a problem due to assembly deviation as in the prior art may not occur.

More specifically, as shown in FIG. 4, the first mold 100 is formed with a circular seating surface 110 in which a rear surface of the support 20 is seated at a central portion, and the seating surface 110 is It is formed in a hollow shape.

In addition, a first groove 120 formed concave in a ring shape along the outer surface of the seating surface 110 is formed on one surface on which the seating surface 110 is formed in the first mold 100, the support described above The guide wall 24 of 20 may be inserted into the first groove 120.

The second mold 200 is coupled to the first mold 100 so that the support portion 20 is in close contact with the front surface of the support portion 20 when the rear surface is seated to be in close contact with the first mold 100.

In this case, on one surface of the second mold 200, a circular core part 210 in close contact with the front surface of the support part 20 and a second groove formed concave in a ring shape along the outer surface of the core part 210 220 is formed.

At this time, when the first and second molds 100 and 200 are positioned and coupled with the support portion 20 therebetween, the guide wall 24 of the support portion 20 is attached to the second groove 220. Is inserted.

On the other hand, one surface of the first mold 100 communicates with the first groove 120 and forms a concave groove shape in the direction from the outer surface of the first groove 120 toward the outside, and extends the air outlet 130 ) Is formed.

When the air discharge unit 130 is formed in a groove shape, the air existing therebetween can be discharged through the air discharge unit 130 when the first and second molds 100 and 200 are combined. Through this, the space between the first and second molds 100 and 200 may be formed by vacuum.

One surface of the second mold 200 communicates with the second groove 220 and forms a concave groove shape in the direction from the outer surface of the second groove 220 toward the outside, and the extended air discharge part 230 Is formed.

In this case, when the first and second molds 100 and 200 are coupled to face each other, the air discharge part 230 is formed on one surface of the second mold 200. It is formed at a position corresponding to the air discharge unit 130 so as to face each other.

That is, the air discharge unit 230 is formed to face each other with the air discharge unit 130 to form a space to discharge the air existing in the space between the first and second molds (100, 200) Accordingly, the number of air outlets 230 may be formed to be the same as the number of air outlets 120.

On the other hand, in the core portion 210 of the second mold 200, the resin injection holes 240 are formed in an axial symmetry at regular intervals with each other, and the support portion 20 seated on the second mold 200 The front of the resin injection holes 240 are formed in the resin injection holes (29, see Fig. 3b) formed in a position facing the.

Thus, when the thermoplastic elastomer described above is injected between the first and second molds 100 and 200, the thermoplastic elastomer passes through the resin injection holes 240 and the resin injection holes 29 in sequence. It is injected into the rear surface of the support portion 20 to cover the rear surface of the support portion 20 and the hollow portion 40. In this case, since the resin injection holes 240 and the resin injection holes 29 are positioned at regular intervals, the rear surface of the support portion 20 between the first and second molds 100 and 200 is It can be evenly interposed in the formed space.

On the other hand, the insert injection mold 10 may further include a heating unit (not shown). The heating unit is formed adjacent to the second mold 200 to apply heat to the thermoplastic elastomer passing through the resin injection holes 240, so that the thermoplastic elastomer is the first and second molds ( 100, 200) to be precisely molded according to the shape of the first and second molds (100, 200).

Meanwhile, first corners 150 having a protruding shape are formed at each corner of one surface on which the seating surface 110 of the first mold 100 is formed, and at each corner of the second mold 200 The first and second molds 100 and 200 are joined by combining the formed second surfaces 250 of the recessed shape.

In particular, an opening-shaped fixture 251 is formed on each of the second surfaces, and the second mold 200 is inserted into the first mold (not shown) by inserting the fixture 251 through a fixing member (not shown). 100) can be fixed more firmly.

As described above, in the state where the first and second molds 100 and 200 are coupled to each other, between the first and second molds 100 and 200, that is, to the rear surface of the support portion 20, the thermoplastic elastomer When injected and cured, the oil-proof part 30 is formed in a shape surrounding a part of the rear surface of the support part 20 and the hollow part 40.

In this case, the oil-proof part 30 and the support part 20 are integrally formed, and there is no need to apply any other material such as an adhesive between the first and second molds 100 and 200, so that the thermoplastic elastomer is not required. Is cured and the oil seal part 30 and the support part 20 form one body to be manufactured as the oil seal 5 for the gear cover.

Then, the oil seal 5 for the gear cover made of the oil seal part 30 and the support part 20 should be taken out between the first and second molds 100 and 200.

In this case, when the second mold 200 is first separated from the first mold 100, the gear cover oil seal 50 remains in close contact with the first mold 100. 1 The oil seal 5 for the gear cover can be easily separated from the second mold through a plurality of extraction holes 160 formed in the seating surface 110 of the mold 100.

That is, air is blown through the blowout holes 160 in the direction toward the oil seal 5 for the gear cover, or a blowout pin (not shown) is directed toward the oil seal 5 for the gear cover. By passing through the field 160, the oil seal 5 for the gear cover can be separated from the second mold 200.

6 is a flowchart illustrating an insert injection method using the mold for insert injection of FIGS. 4 and 5. 7A to 7D are process diagrams showing the insert injection method of FIG. 6.

Hereinafter, with reference to FIGS. 6 and 7A to 7D, an insert injection method for manufacturing the oil seal 5 for the gear cover using the insert injection mold 10 described above will be described.

6 and 7A, the support part 20 is seated on the seating surface 110 of the first mold 100 (S100).

Next, referring to FIGS. 6 and 7B, the second mold 200 is coupled to the first mold 100 (step S200). When the first and second molds 100 and 200 are combined, an injection space 400 is formed between the first and second molds 100 and 200.

Thereafter, referring to FIGS. 6 and 7C, the thermoplastic elastomer 500 is injected into the injection space 400 between the first and second molds 100 and 200. In this case, the thermoplastic elastomer 500 is injected in a form that covers the rear surface of the support part 20 and the hollow part 40 in the injection space 400 and is formed as the oil seal part 30 as it is cured. .

Next, referring to FIGS. 6 and 7D, after separating the second mold 200 from the first mold 100, the extraction holes 160 formed in the first mold 100 described above. Inject air into or through the blow pin.

Then, as shown in Figure 7e, the oil cover 5 for the gear cover consisting of the support portion 20 and the oil-proof portion 30 is taken out from the first substrate 100 (step S300), for the gear cover The oil seal can be installed and used in a gear box (not shown).

According to embodiments of the present invention, the support is inserted into the insert between the first and second molds, a thermoplastic elastomer (Thermo Plastic Elastomer) that does not require a complicated preparation step such as basis weight, mixing / kneading, aging on the support , TPE) material can be injected to reduce process steps and increase stability to produce high quality products with minimal defects.

In particular, by using only a single material, TPE, as a material injected between the first and second molds, it is possible to reduce the defect rate of the oil seal through material simplification and minimize the hardness defect, and furthermore, recycling of the TPE material is possible. It is possible to improve the eco-friendliness.

In addition, since the melted TPE is injected into the support portion seated between the first and second molds to form an oil-proof portion, close clamping between the support portion and the oil-proof portion is possible, thereby eliminating assembly defects, thereby improving dimensional accuracy and assembly. It can be improved, and the process of material preparation, measurement, aging, cutting, etc. in the prior art can be omitted, so that high-speed processing, which is a characteristic of injection molding, is possible, thereby improving production speed and productivity.

Although described above with reference to the preferred embodiments of the present invention, those skilled in the art may variously modify and change the present invention without departing from the spirit and scope of the present invention as set forth in the claims below. You will understand that you can.

5: Oil seal for gear cover 10: Insert injection mold
20: support 30: oil-proof
100: first mold 110: seating surface
120: first groove 130: air outlet
160: extraction holes 150: first sides
200: second mold 210: core
220: second groove 230: air outlet
250: second sides

Claims (9)

In the insert injection mold for manufacturing an oil seal for a gear box consisting of a support part and an oil-proof part,
A first mold in which a circular seating surface on which a rear surface of the support part is seated is formed in a central portion; And
Combined with the first mold, a circular core portion in which a front surface of the support portion is seated is formed in a central portion, and a thermoplastic elastomer is injected into the space between the first mold through the resin injection holes formed in the core portion, and the oil seal portion It includes a second mold is formed,
The support portion is formed with a resin seating surface having a ring-shaped groove in the space between the outermost guide wall and the hollow portion located inside the guide wall,
The front surface of the support part is not covered by the oil seal part, and the rear surface of the support part is covered by the oil seal part and the back surface of the resin seating surface is covered.
The oil-proof part is in the form surrounding the back of the support part, characterized in that formed by the hollow portion to be spaced apart from each other for injection mold. According to claim 1,
A first groove recessed in a ring shape is formed along an outer surface of the seating surface on one surface of the first mold,
A mold for insert injection characterized in that a second groove recessed in a ring shape is formed along an outer surface of the core part on a surface facing the first mold of the second mold. According to claim 2,
An air discharge part communicating with the first groove to form a concave groove shape and discharging air between the first and second molds is formed on one surface of the first mold,
A mold for insert injection characterized in that an air discharge portion formed to face the air discharge portion and to form a concave groove in communication with the second groove is formed on a surface facing the first mold of the second mold. According to claim 2,
When the first and second molds are coupled while the support is seated therebetween,
A mold for insert injection characterized in that the rear and front surfaces of the guide wall formed along the circumference in the support part are respectively inserted into the first and second grooves, respectively. According to claim 1, The resin injection port,
A mold for insert injection, characterized in that the core portion is formed in an axisymmetric shape at regular intervals. According to claim 1, The seating surface,
A mold for insert injection, characterized in that a plurality of ejection holes through which the air is injected or through which the ejection pin is penetrated are formed in axial symmetry. According to claim 1,
The first surfaces of the protruding shape are formed at each corner of one surface of the first mold, and the corners of the surfaces facing the first mold of the second mold are recessed to be coupled to each of the first surfaces. The second sides of the shape are formed,
A mold for insert injection, characterized in that a fastener having an open shape is formed on each of the second surfaces. According to claim 1,
A mold for insert injection that is installed adjacent to the second mold and further includes a heating unit that applies heat to the thermoplastic elastomer passing through the resin injection holes. In the insert injection method using the insert injection mold of claim 1,
Seating the support portion on a seating surface of a first mold;
Combining a second mold with the first mold;
Injecting a thermoplastic elastomer into the back and the hollow of the support portion to form an oil seal to produce an oil seal for a gear cover; And
And separating the second mold from the first mold, and then taking out the oil seal for the gear cover from the second mold.

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