DE2558406A1 - METHOD OF MANUFACTURING RESILIENTLY RESILIENT ARTICLES AND ARTICLES MANUFACTURED BY THE METHOD - Google Patents

Description

Dr. F. Zumstein Sr. - Dr. E. Assmann - Dr. R. Koenigsberger Dipl.-Phys. R. Holzbauer - Dipl.-Ing. F. Klingseisen - Dr. F Zumstein jun.

PATENT LAWYERS

TELEPHONE: COLLECTIVE NO. 22 5341

TELEX 529979 TELEGRAMS: ZUMPAT

CHECK ACCOUNT: MUNICH 91139-8O9. Bank code 700 100 8O BANK ACCOUNT: BANKHAUS H. AUFHÄUSER

ACCOUNT NO. 397997. BLZ 70030600

8 MUNICH 2.

BRÄUHAUSSTRASSE 4

Case ΡΥ.5549 / 5550 (Cognate)
6 / DE

DUWLOP LIMITED, London, Great Britain

Method of making resilient articles and articles made by the method

The invention relates to a method for producing resiliently flexible objects as well as objects produced by the method Objects. In particular, the invention relates to articles in which elastomeric material is used to form a resiliently compliant Section or sections of the object are provided. These items are, for example, as resilient, Fastening devices that act as damping are intended in mechanical engineering, as well as for springs and axes of rotation, etc. for suspensions.

Such articles have rigid metal members which are adhered with a suitable elastomeric material such as rubber, connected, however, is the manufacture of such facilities and items are labor-intensive and time-consuming. The objects themselves are as a result of difficulties in the for

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the connection process required production of the metal surfaces expensive. In particular, from a manufacturing point of view when producing metal members with regard to the economic feasibility set limits, and reliability of the manufactured product is often affected by the effect of the adhesive bond due to corrosion and Deteriorated pollution during manufacture.

According to the invention, a method for producing an object is characterized, consisting of an element made of elastomeric material and at least one element of plastics material adhered to the elastomeric element by the fact that a first porous cavity from the elastomeric or plastic-like one Material is ingested while at least a second adjacent mold cavity is filled with a rigid spacer insert that the rigid insert is removed and that the empty second mold cavity with plastic-like or elastomeric material is filled in, the process, on the one hand, the removal of the insert and the subsequent filling with something similar to plastic or elastomeric material, is repeated until the plastic-like / elastomeric article is completed and that this object is removed from the mold.

In a first process stage, a preformed one is mechanically formed Part made of plastic or rubber material is introduced into a first mold cavity, or the material can also be injected into the mold cavity. It is essential to the invention that one injection process in the second Mold cavity or in the second mold cavities either with a plastic material or with a non-vulcanized one Natural rubber material or with synthetic rubber material can be carried out.

Preferably the plastic material is applied to the elastomeric material injection molded so that there is a fusion bond between

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the individual parts due to the predetermined pressure and the temperature of the materials, which of the actually selected materials to be connected are dependent. Yfenn an adhesive connection is established immediately, and the partially molded article can be retained in its shape by the adhesive bond in the mold cavity, while the next rigid insert is being removed, a simply constructed mold cavity can be used.

The method is particularly suitable for molding natural or synthetic rubber. The plastic materials that Suitable for this include nylon and filler materials and may vary according to the physical properties required to be selected.

The inlays or inserts can be removed when the mold is opened or with the aid of automatic ejectors.

Preferably, the method according to the invention is designed so that the preformed plastic or rubber part in its Position - in the mold cavity by reducing the pressure at least partially is held on the surface of the preformed part in contact with the mold.

The pressure reduction is preferably carried out with the aid of a vacuum pump, which is connected to an air inlet in the mold which opens on the surface of the mold in contact with the preformed one Part stands. In particular, several inlets can be provided, and the inlet (s) can be provided with a shaped, th vacuum surface in connection, which corresponds to the shape of the part that is to be held in its position in the mold, is equivalent to. The part is preferably designed in such a way that it is effectively held in its position by the pressure reduction, what is achieved for example with the help of a sealing lip - which is formed on the edges of the parts

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The pressure reduction can be controlled automatically either with the help of an air valve or a switch for the vacuum pump will. The valve or switch is activated by the movement of the interlocking mold parts or mold halves, respectively actuates the movement of the rubber or plastic applicators. Preferably the design is taken so that the ejector plate actuates this switch for ejecting a finished part.

The invention also relates to a composite article which is made up of at least one part of an elastomeric material and at least one further part consists of a plastic material, which are adhesively connected to one another, and this The composite object is characterized in that a device for mechanically attaching the PIa label part to the plastic part is provided with a part to which the object is to be firmly connected.

This fastening device can be a tapered bore in the plastic element with a corresponding tapered pin cooperates. Furthermore, recesses, grooves, depressions, serrations, keyways or similar structures can also be used be formed in the plastic part. Furthermore, internal or external threads can be provided, or the plastic part can also have flanges.

According to a preferred embodiment, the object a rubber ring that adheres to each curved surface with a plastic tube to form a resilient Bearing bush is adhesively connected.

In addition, more than one part made of an elastomeric material can be used for a correspondingly complex object be provided. For this purpose, a rubber bushing is listed, for example, which has an inner and an outer rigid part

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and includes an enclosed rigid part. The formation of the enclosed rigid part is possible in that a A corresponding cavity is provided which is filled in at the appropriate time during the plastic injection molding process.

Further details, features and advantages of the invention emerge from the following description of preferred embodiments according to the invention with reference to the accompanying drawings.

Piguren 1 to 5 show five process steps for injection molding a cylindrical rubber bush, which inner and Has outer parts made of plastic.

Piguren 6 to 11 show different embodiments of a Item according to the invention.

A Pormhohlraum comprises a main part 1 and an end plate 2. A cylindrical opening 3 is provided in the main part, the outer diameter of which corresponds to the outer diameter of the bushing to be produced. Injection molding sites 4 and 5 are provided accordingly, as will be described later. The end plate 2 has a circular gap 6 and a steel core sleeve 7 which is identical in dimensions to the inner sleeve in the finished object

and this can be adapted in shape to the gap 6. Projections 8 are arranged along the outer circumference 6a of the gap, the shape of which is complementary to the side of the elastomeric bushing which is used in the method. A similar embodiment is provided on the main part 1, so that the other side of the elastomeric bushing does so fits. Further details are provided in the appropriate places when discussing the method of making a socket explained.

A preformed, vulcanized, circular rubber sleeve 9

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is pushed over the core sleeve 7, which is held in a position that it protrudes beyond the gap 6, as shown in FIG. The projection 8 rests against an edge of the rubber bush 9. Passages 8a for the negative pressure can be provided accordingly in order to fix the socket 9 in position with the aid of an air pressure difference. The end plate 2 adjoins the main part 1, as shown in Figure 3, and an injection nozzle delivers Fylon at an appropriate temperature and pressure via feed s inlets into the injection molding points 5, the circular space for forming the outer plastic sleeve 10 of the socket fills up and at the same time an adhesive connection with the rubber socket 9 is established. The core sleeve 7 is pushed back into the gap 6 and further nylon is fed in via the injection molding points 4 to form the inner sleeve 11 of the bushing, as shown in FIG. The mold is then opened and the finished socket is injection molded, as shown in FIG. The plastic parts are formed during the pressing and injection molding process and bonded to the elastomeric material.

Since the injection parameters are selected in such a way that a fusion bond is created between the rubber and the nylon, the end plate 2 can be withdrawn from the main mold part 1, to pull out the core sleeve because the uylon is in the injection molding point 5 holds the rubber bushing 9 in the form by the adhesive connection with the other sleeve 10 the mold end plate 2 does not have to be designed to be subdivided and there is no need for any means for holding the outer sleeve 10 in place and the socket 9 to be provided when the core sleeve 7 is pulled out.

For carrying out the method according to the invention are materials preferably suitable, which are thermoplastic and can be heated in such a way that at least the surface melts,

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while in contact with a compatible elastomer, and which can be cooled while the materials are with each other stand in touch.

The rubber and the plastic can have various ingredients such. B. Pilling materials, pigments, anti-aging agents, for processing required oils, etc., which are known.

^ If necessary, the surfaces of the rubber composition be pretreated prior to injection molding in order to achieve the required adhesion between the rubber composition and the thermoplastic composition to improve.

Suitable pretreatments include surface treatment of the rubber composition with chemical means, for example using acidified sodium hypochlorite, more concentrated Nitric acid, aqueous solution of trichloroisocyanuric acid (Pi-clor 91) »Uatriumdichlorisoeyanuräure (]? I-elor 60S) or a 1% (weight / volume) dioxone solution of 4 (p-carboxphenyl) -3 * 5-triazoline-2-4-dione. The surface of the rubber composition can be subjected to this pretreatment in any known manner be subjected, for example by dipping, spraying or applying. The treatment time is calculated so that the Surface of the rubber composition is modified without the core of the rubber is adversely changed, and the ^ excess residue of the reactant is removed after treatment if this is detrimental to the plastic composition influenced. On the other hand, the surface of the rubber can be pretreated by exposing it to ultraviolet radiation will.

The resilient bushing that was described at the beginning is, represents only one embodiment, which by repeated injection molding process to form plastic parts

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is formed while at the same time creating an adhesive bond with an elastomeric material. Such rubber bushings are often provided as resilient connections both in machines and in motor vehicles. Such sockets are common in the installed state and this can be done in the case of a plastic rubber bushing by expanding the middle rubber sleeve be carried out when installing the object. This can be done in different ways, for example with a fitting bolt that is pressed into the sleeve (Figure 6), a taper bolt that is pushed into the sleeve with the help of a Nut is pulled into the sleeve (Figure 7), with two bolts that stretch the inner sleeve (Figure 8), a single one Expansion bolt (Figure 9), and the expansion of the inner Sleeve can also be performed so that the outer sleeve is also stretched by inserting the outer sleeve into an opening into which the bushing is to be installed «This means that there are no fits with tight tolerances, as is the case with the installation of rubber-metal bushings necessary. On the other hand, the outer band can be compressed around the elastomeric material as well to pretension. An advantage of the invention is that a socket can be made automatically, for which purpose no special treatment needs to be provided for the sleeves for adhesion, and there is also a manufacturing process not the risk of corrosion, as is the case with metal parts. Furthermore, the operations can be carried out without any human Work force to be carried out. This advantage can be achieved in that the rubber ring 9 is automatically cast, and that this is mechanically introduced into the mold. If necessary, the circular sleeve can be cast in the same mold 1 by placing two pull-out core sleeves, one each for the inner and outer sleeve, are introduced, and in the rubber is injected into the resulting annular space. This This is particularly advantageous when using rapidly vulcanizing materials.

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.. 9 -

A major advantage when molding the plastic parts is in that these can be complex in shape, as well as projections for defining the part made of elastomeric material and / or the material itself can be provided in which the Objects are to be accommodated. Keyways, keyways, etc. can also be formed and the cost of a such special shape are only reflected in the cost of the mold, so that the method according to the invention in particular is economical for mass-produced items.

Figures 10 and 11 show preferred embodiments which can be applied to the inner sleeve to make a sufficiently strong connection with a part that is overmolded on the socket is to ensure. In addition to the expansion of the inner sleeve as described above, flanges (Figure 10) or prongs (Figure 11) may be provided.

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Claims (17)

Patent claims "Method of manufacturing an object, consisting of a part made of elastomeric material and at least one part made of plastic material, which is adhesively connected to this is characterized in that a first mold cavity with the elastomeric material and the plastic material is filled in, while at least one adjoining lOrm cavity is filled with a rigid insert (7), that the rigid insert (7) is removed, and that the second Pormhohlraum with plastic material or elastomeric material is filled, with the removal of the insert and filling with plastic material or elastomeric material is repeated until the object, consisting of plastic material and elastomer material, is completed, and that then the object is removed from the mold (1). 2. The method according to claim 1, characterized in that the elastomeric material or the plastic material which the occupy the first cavity, shaped according to the shape of this cavity in a second shape, and that this is introduced into the first lOrm cavity. 3. The method according to claim 1, characterized in that the It is introduced mechanically. 4 ·. Method according to claim 1, characterized in that the elastomeric material or the plastic material is injected into the first porous cavity. 5. The method according to claim 1, 2 or 3, characterized in that v / at least the second adjacent l orm cavity by injection Clay plastic material or elastomeric material at such a temperature and pressure. 609832/0599 fills -will. that enamel adhesion with the material that is located in the Pormhohlraum, arises. 6. The method according to claim 5, characterized in that the adhesive connection between the injection molded plastic material or elastomeric material to the partially molded Form object in the Porm while the next rigid insert (7) is removed. 7. The method according to any one of claims 1 to 6, characterized in that that the insert (7) is removed with the help of an automatically operated Au swu rf device. 8. The method according to any one of claims 1 to 7, characterized in that that the prefabricated material (9) which fills the first Pormhohlraum, held in this cavity thereby is that at least partially on the surface of the preformed part the pressure is reduced, which is associated with the Porm (3) in Touch is. 9. The method according to claim 8, characterized in that the pressure reduction is carried out with a vacuum pump with a Air inlet (8a) in the Porm (3) on the surface (8) of the Porm is connected, which is in contact with the prefabricated rope. 10. The method according to claim 9, characterized in that a Sealing lip is formed on the preformed part. 11. The method according to claim 8, 9 or 10, characterized in that that the pressure reduction is controlled by the movement of the interlocking Pormteile. 12. The method according to claim 8, 9 or 10, characterized in that the pressure reduction by the movement of the supply organs 609 8 32/0599 for the rubber or plastic material is controlled. 15. The method according to claim 8, 9 or 10, characterized in that that the pressure reduction is actuated by the actuation of the ejection plate, which the previously shaped object ejects. 14 ·. Composite article consisting of at least one Part made of an elastomeric material and at least one part made of a plastic material that is adhesively connected to it is characterized by devices for mechanical plaguing of the part made of plastic, on a part with which the Object is to be firmly connected. 15. The object of claim 14 »characterized in that the Device for fixing is formed as a conical bore in the part made of plastic, which is provided with a corresponding conical pin comes into engagement. 16. The object of claim I4, characterized in that Sealing devices are provided with recesses in the part made of plastic. 17. The object of claim 14 »characterized in that the fasteners are pedestal grooves on the plastic part. 609832/0599