Textiles: spinning – twisting – and twining – Apparatus and processes – Open end spinning
Reexamination Certificate
2001-09-24
2003-03-11
Worrell, Danny (Department: 3765)
Textiles: spinning, twisting, and twining
Apparatus and processes
Open end spinning
Reexamination Certificate
active
06530206
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a supporting disk for supporting a rotor of an open-end spinning machine, including a hub ring and a supporting ring made of polymeric material affixed to its periphery.
BACKGROUND INFORMATION
Such supporting disks are generally known, the hub ring being made exclusively of a metallic material, such as aluminum, or made exclusively of a nonmetallic material, such as a polymeric material.
The advantage of a hub ring made of a metallic material is to be seen in its good thermal conductivity, its great mechanical strength and its good workability. The disadvantage with such hub rings is the comparatively great weight, the high energy requirement resulting from this during frequently occurring braking and starting events, for example, during starting spinning of the open-end spinning machine, and the comparatively high price of metallic materials.
Hub rings made of polymeric materials are also known from the related art. A hub ring made of polymeric material is of advantage, because of its low weight as well as its simple and cost-effective manufacturability. Hub rings made of polymeric materials have the disadvantages of considerably lower heat conductivity and lower mechanical strength compared to metallic materials. Because of the relaxation of many plastics, there is a danger that the press fit between the drive shaft and the hub ring may loosen with increasing time of use, and that the hub ring will change its position with respect to the shaft.
SUMMARY OF THE INVENTION
The present invention is based on the object of developing further a supporting disk, of the kind named at the beginning, in such a way that the supporting disk has a good thermal conductivity, a sufficiently great mechanical strength, a low weight, as well as being producible in a cost-effective manner. The low weight is intended to reduce to a minimum the energy demand during braking and starting when starting spinning in the open-end spinning machine.
The object of the present invention is achieved by the features of claim
1
. The dependent claims refer to advantageous refinements.
To attain the object, it is provided that the hub ring is developed as a composite part and is made of at least two different materials. The advantageous properties of each material are thereby used in optimal fashion for partial areas of the object to be attained. Disadvantageous properties of each material do not have a disadvantageous influence on the working properties of the supporting disk, but are compensated for by the positive properties of the other material in each case.
According to one advantageous development, it can be provided that the hub ring includes a metallic and a polymeric material which are connected to each other in a force-locking or a form-locking manner. It is an advantage with such a choice of materials that the metallic material involves good thermal conductivity and great mechanical strength, as well as good workability, while the polymeric material contributes measurably to the low weight of the supporting disk and to its cost-effective manufacturing. In that case the metallic part of the hub ring can be reduced to the minimum that is technically necessary. Through the combination of metallic and polymeric materials, each of the materials contributes only its advantageous properties, so that the hub ring is optimized overall with regard to its working properties as well as in regard to its economical manufacturability.
The hub ring can be formed by a disk made of a metallic material which is overlapped at least partially by at least one plastic element. Preferably the disk is made as an aluminum disk. The aluminum disk brings about good thermal conductivity out of the support ring, on which the rotor runs, into the surroundings, and a sufficient mechanical strength of the hub ring. Since the size of the aluminum disk is reduced to the minimum technically necessary, and the remainder of the hub ring, on the other hand, is formed by the plastic element, the supporting ring has only a low weight overall, and can be made simply and cost-effectively. The plastic element is used, for example, for obtaining a sufficiently large surface for fixing the supporting ring and/or a sufficiently large seat for the pressure fit with which the hub ring is pressed onto the shaft or onto a journal on the shaft. The aluminum disk can have a thickness between 0.5 mm and 6 mm, preferably 3 mm.
The circumference of the plastic element and the inner circumference of the supporting ring can be connected to each other by force-locking or form-locking. It has proven especially advantageous for the plastic element and the supporting ring to be connected to each other by force-locking and form-locking. In this connection it can be provided that, in a first method step, at first the aluminum disk is extrusion-coated with the polymeric material of which the plastic component is made, in order thereby to make the hub ring. In a further, second method step the polymeric material of the supporting ring is, for example, deposited on the completed hub ring also by injection molding.
Aside from the use of an injection molding process, the supporting ring can also be pressed on or poured on, for example. Beyond that, there is the possibility of applying a two-component injection molding process, in the injection molding process, in general, the same machine being used for producing the hub ring and the supporting ring. The hub ring, for example, can be made of a thermoplastic, and the supporting ring, on the other hand, can be made of a thermoplastic polyurethane. In such a method, investment costs for the production equipment are only very low.
In view of the method steps according to which the aluminum disk, which may be stamped, for example, is first of all extrusion coated with plastic to create the hub ring, the hub ring subsequently being extrusion coated with the material of the supporting ring, it is of advantage that the strength of the processed materials decreases with each working step. The advantages lie in the handling, and since the harder precursor product in each case acts in a stabilizing manner the product is easy to handle at each point in time of manufacturing. By contrast, handling would be substantially more difficult using an opposite sequence, if, for example, one had to work on a soft supporting ring.
Since the plastic of the hub ring is very hard and strong compared to the material of the supporting ring, and melts at higher temperatures, it is possible to produce the plastic regions of the hub ring with great dimensional precision and to handle them with ease. This dimensional precision is not even influenced in a negative way by the hotly sprayed on but lower melting material of the supporting ring. The tying-up of the manufacturer's capital in semi-finished products is relatively low, since both the aluminum disk, especially when it is stamped, is produced very cost-effectively, and the plastic for the hub ring, which, compared to the plastic of which the supporting ring is made, is also favorable.
However, it is also possible to extrusion-coat the aluminum disk in a first method step with the polymeric material of the supporting ring, and subsequently, in a second method step, to spray the supporting geometries in hard plastic, e.g. using the injection molding method, onto the preassembled unit made up of the aluminum disk and the supporting ring. Since the harder plastic for the hub ring melts only at higher temperatures than the material of which the supporting ring is made, an appropriate selection of plastic can bring about fusing of the hub ring plastic with the supporting ring material, and therefore a good bonding of the two materials. As the material, glass fiber-reinforced polyurethane, for example, comes into consideration.
The overlapping of the aluminum disk with a plastic element takes place only in partial regions in which this is also technically necessary.
The circumference of the plastic element and the inner circumferenc
Firma Carl Freudenberg
Kenyon & Kenyon
Worrell Danny
LandOfFree
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