JPH04813B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a method for producing a vibration isolating rubber with metal fittings such as a bushing used for cushioning the connecting parts of various rods in suspension systems, steering systems, etc. of automobiles. [Prior Art] Anti-vibration rubber with fittings, especially bushings, are generally made by fitting an outer cylindrical fitting 2 onto an inner cylindrical fitting 1 and gluing it into the gap between the two fittings 1 and 2, as shown in Figs. 3 and 4. After injecting unvulcanized rubber for the sleeve through the agent layer and vulcanizing it to form a rubber sleeve 3 and adhering it, the outer cylindrical fitting 2 is drawn to reduce its diameter, or the inner cylindrical fitting 1 is The rubber sleeve 3 between the inner and outer cylinders is compressed in the direction perpendicular to the axis by expanding the diameter of the rubber sleeve 3 (see FIG. 5). Rust prevention for this type of bushing is carried out by immersing the entire bushing in an organic solvent-based anticorrosive paint after manufacture, and then baking it. This is due to the following reasons. In other words, even if the inner and outer cylindrical fittings 1 and 2 are subjected to anti-corrosion treatment such as metal plating in advance to form a plating film, the plating film will be damaged during diameter expansion and diameter reduction of the inner and outer cylindrical fittings 1 and 2. On the other hand, tensile stress and compressive stress act on the plating film, causing it to peel off. The same effect can be obtained by forming a chemical conversion film made of zinc phosphate or manganese phosphate in place of the plating film. Therefore, the reality is that the inner and outer cylindrical fittings 1 and 2 are rust-proofed by immersing the entire bushing in anti-rust paint after manufacturing as described above. [Problem to be solved by the invention] However, since painting with anti-corrosion paint cannot provide sufficient rust prevention for the inner and outer cylindrical fittings 1 and 2, it cannot be used under corrosive conditions such as water, salt water, etc. In use, water, salt water, etc. enter from the contact surface between the rubber sleeve 3 and the inner and outer cylindrical fittings 1 and 2, and this acts on the parts of the inner and outer cylindrical fittings that are incompletely rust-proofed, causing a local battery phenomenon. It gradually expands and the entire contact surface of the inner and outer cylindrical fittings 1 and 2 is attacked, resulting in thinning. As a result, the adhesive layer that adhered the rubber sleeve 3 to the inner and outer cylindrical fittings 1 and 2 disappears along with the base of the inner and outer cylindrical fittings, and the adhesiveness of the rubber sleeve to the inner and outer cylindrical fittings 1 and 2 disappears. This poses a serious practical problem in that the rubber sleeve 3 becomes damaged and comes off. Further, the above conventional method uses an organic solvent-based anticorrosion paint, and therefore has the disadvantage of causing health and safety problems. Other conventional methods for manufacturing bushings include applying chemical conversion treatment to the inner cylinder fitting 1 and outer cylinder fitting 2 in advance to form a chemical conversion film, or applying electrodeposition coating to form an electrodeposition coating film. There is a method of manufacturing a bush by injecting unvulcanized rubber between the inner and outer cylindrical fittings 1 and 2 coated with these films (coating film), vulcanizing the rubber, and then expanding the diameter of the inner cylinder. Unlike the conventional method mentioned above, this method does not use an organic solvent-based anti-corrosive paint and bake the bushings to prevent rusting, as in the conventional method described above, resulting in safety and health problems and the deterioration of the physical properties of the rubber due to the heat during baking. Does not cause any problems. However, the chemical conversion treatment method requires special equipment, which makes the entire device large-scale, and also requires a large amount of expense for waste liquid treatment, resulting in the problem of increased product costs. In addition, since electrodeposition equipment uses high-temperature baking at 170 to 200°C, paints whose main component is epoxy resin, which is a high-temperature curing resin, are used, which increases the rigidity of the resulting coating film. Therefore, when the inner cylinder is expanded in diameter and the rubber sleeve 3 is pre-compressed, cracks occur in the formed coating film, which leads to corrosion of the inner and outer cylinder fittings 1 and 2, which is a drawback. Moreover, like the chemical conversion treatment described above, electrodeposition coating requires special equipment and has the disadvantage that the equipment becomes large-scale. The present invention was made in view of the above circumstances, and an object of the present invention is to manufacture a vibration-proof rubber with metal fittings having high corrosion resistance without requiring large-scale equipment and at low cost. [Means for Solving the Problems] In order to achieve the above object, the manufacturing method of the vibration isolating rubber with metal fittings of the present invention involves injection molding the metal fittings using a thermoplastic resin. The metal fitting is coated with a film, and a vibration isolating rubber member is integrally formed on a predetermined portion of the metal fitting covered with the thermoplastic resin film via an adhesive layer. In other words, as a result of repeated research on resins that can form a resin film that can sufficiently follow the deformation of metal fittings during processing such as expanding the diameter of the inner cylinder, the inventor found that thermoplastic resins are suitable for this purpose. If the metal fittings are coated with this resin in advance using a conventionally known injection molding machine, the metal fittings will be insulated by the coating resin film and the occurrence of the above-mentioned local battery phenomenon will be prevented. Since the resin coating by injection molding is performed prior to disposing the rubber member, thermal deterioration of the rubber member does not occur, and since the above coating is performed using a conventionally known injection molding machine,
The present invention was achieved by discovering that no large-scale equipment is required, and since no organic solvent is used, there are no safety and health problems. As mentioned above, the vibration isolating rubber with metal fittings of this invention has the following features:
It is obtained by previously covering a metal fitting with a thermoplastic resin film by injection molding, and then forming a vibration-proof rubber member on a predetermined portion of the resin-coated metal fitting via an adhesive layer. Here, the above-mentioned covering includes not only the case where the entire metal fitting is covered with resin, but also the case where a part of the metal fitting is covered with resin. The metal fittings mentioned above are not particularly limited. As the anti-vibration rubber with metal fittings, for example, when manufacturing a bush, conventionally used inner and outer cylindrical metal fittings can be used as they are (after being degreased and cleaned). In this case, it is preferable to use metal fittings that do not have a plating film that peels off when the inner and outer cylinders are expanded or contracted in diameter. When manufacturing engine mounts and the like as the anti-vibration rubber with metal fittings, the above-mentioned problems do not occur, and the anti-vibration rubber with metal fittings can be used regardless of whether it is plated or not. In order to improve the adhesion between the thermoplastic resin film and the metal fitting, it is desirable to roughen the surface of the metal fitting by subjecting it to shot blasting or the like. For the above injection molding, a wide variety of conventionally known injection molding machines can be used. As described above, a major feature of the present invention is that a conventionally known injection molding machine can be used as is, and no special equipment is required. The thermoplastic resin used in this injection molding is not particularly limited, and any type of resin can be used. Excellent from the viewpoint of injection moldability. The mold used for injection molding as described above has a surface of 5 to
It is preferable to use a material that can form a rough surface with irregularities of about 20 μm. By forming a rough surface on the surface of the thermoplastic resin film as described above, the adhesion to the rubber member can be significantly improved. The formation of a vibration-proof rubber member on a predetermined portion of the thermoplastic resin coated metal fittings is usually done by applying a one-component or two-component vulcanizing adhesive for rubber and metal to the part where the rubber member is to be formed. Vulcanized rubber is injected and vulcanized adhesion is performed. For example, when manufacturing a bushing as a vibration-proof rubber with metal fittings, this rubber injection is carried out.
This can be done by injecting unvulcanized rubber into the gap between the inner cylindrical metal fitting and the outer cylindrical metal fitting. Another method for forming a vibration-proof rubber member is to arrange a rubber member that has been vulcanized in advance at the predetermined portion and heat-bond it (post-bond). According to this method, vibration-proof rubber members can be formed extremely easily on metal fittings having various shapes. In this way, the desired vibration isolating rubber with metal fittings is obtained, but depending on the type of vibration isolating rubber with metal fittings, further post-processing is performed. For example, when the anti-vibration rubber with metal fittings is a bush, the rubber member is pre-compressed by expanding the diameter of the inner cylinder or contracting the diameter of the outer cylinder. In this case, in the anti-vibration rubber with metal fittings of the present invention, the metal fittings, that is, the inner and outer cylindrical metal fittings, are coated with a thermoplastic resin film that is highly adaptable to bending processes, so this film is sufficient for the above processing. This is a major feature of the resin film, as it follows the pattern and does not cause any cracks or the like in the resin film. [Effects of the Invention] As described above, the manufacturing method of the vibration isolating rubber with metal fittings of the present invention involves injection molding the metal fittings using a thermoplastic resin and coating the metal fittings with a thermoplastic resin film. The metal fittings are insulated with a thermoplastic resin film, so even if salt water or the like gets wet, local battery phenomenon will not occur on the metal fittings. Therefore, it becomes possible to manufacture a vibration isolating rubber with metal fittings that has an extremely long life. Furthermore, since the above-mentioned coating is performed using a conventionally known injection molding machine, there is no need for large-scale special equipment, and there are no problems such as waste liquid treatment, so it can be manufactured at low cost. Next, an embodiment in which the present invention is applied to a bush will be described. [Example] Degreasing and degreasing of the inner and outer cylinder fittings with perclean vapor (steam temperature 120°C, cleaning time 5 to 30 minutes)
The outer peripheral surface of the inner cylindrical metal fitting and the inner peripheral surface of the outer cylindrical metal fitting were then subjected to grit blasting treatment to roughen the surface. The surface roughening is preferably set to a surface roughness of 5 to 50μ, preferably 10 to 40μ. In this example, it was set to 13μ. Next, the above-mentioned inner and outer cylindrical fittings were placed in a conventionally known injection mold, and a nylon resin film having a thickness of 2 μm to 2 mm was formed on the outer circumferential surface of the inner cylindrical fitting and the inner circumferential surface of the outer cylindrical fitting, respectively, by injection molding. Next, an adhesive was applied to the outer peripheral surface of the inner cylindrical metal fitting and the inner peripheral surface of the outer cylindrical metal fitting on which the resin film was formed as described above. As the adhesive, a one-component or two-component vulcanized adhesive for rubber and metal, which has good wettability to the resin film, was used. The inner and outer cylindrical fittings coated with adhesive in this way are placed in a vulcanization mold, and in that state, an unvulcanized rubber elastic body is injected and the inner and outer cylindrical fittings are integrally vulcanized and bonded. A bush was obtained that had a double tube structure and had a rubber sleeve between both metal fittings before pre-pressurization. Then, the diameter of the inner cylinder was expanded using a die, and the rubber sleeve was compressed in the direction perpendicular to the axis to obtain the desired bush. The bush thus obtained is shown in FIG. In the figure, 1 is an inner cylindrical metal fitting, 2 is an outer cylindrical metal fitting,
3 is a rubber sleeve, 4a and 4b are nylon resin films, and 5 is an adhesive layer. The performance of this bushing (Example 1) was compared with that of a bushing (Example 2) obtained in the same manner as above except that the inner cylinder diameter expansion ratio was changed, and an inner and outer cylinder coated with an epoxy resin coating film by electrodeposition. Comparisons were made with conventional bushes (Comparative Examples 1 and 2) obtained in the same manner as above except for using metal fittings, and with conventional bushes obtained by baking organic solvent-based paint after the bushes were manufactured (Comparative Example 3). are shown in the table below.

【table】

[Table] From Table 1, the adhesive strength of the rubber sleeve of the example product is extremely strong, and the contact surfaces of the inner and outer cylindrical metal fittings are not corroded even when sprayed with salt water. Therefore, the adhesive strength of the rubber sleeve is almost negligible. It can be seen that it has not decreased.
On the other hand, in Comparative Examples 1, 2, and 3, the adhesiveness of the rubber sleeve was impaired due to corrosion caused by the local battery phenomenon, and no great force was required to pull out the rubber sleeve. The above effects can also be obtained by providing a flange portion on the outer cylindrical fitting 2 as shown in FIG.

[Brief explanation of drawings]

FIG. 1 is a vertical cross-sectional view of a bush obtained according to an embodiment of the present invention, FIG. 2 is a vertical cross-sectional view of a modified example thereof, FIG. 3 is a perspective view of a conventional bush before preliminary compression, and FIG. FIG. 4 is a longitudinal sectional view thereof, and FIG. 5 is a longitudinal sectional view after preliminary compression. 1... Inner tube metal fitting, 2... Outer tube metal fitting, 3... Rubber sleeve, 4a, 4b... Nylon resin film.

Claims (1)

[Scope of Claims] 1. A metal fitting is injection molded using a thermoplastic resin to cover the metal fitting with a thermoplastic resin film, and a predetermined portion of the metal fitting covered with the thermoplastic resin film is coated with an adhesive. A method for producing a vibration isolating rubber with metal fittings, characterized by integrally forming a vibration isolating rubber member through layers. 2. The method for manufacturing a vibration isolating rubber with metal fittings according to claim 1, wherein the metal fittings are an inner cylindrical metal fitting and an outer cylindrical metal fitting, and the vibration isolating rubber member is a rubber sleeve disposed between these two metal fittings. 3. The method for manufacturing a vibration isolating rubber with fittings according to claim 1, wherein the thermoplastic resin is a nylon resin.