CN105814248A - Spinning or twisting ring - Google Patents

Abstract

The invention relates to a spinning ring or a twisting ring for a ring spinning machine or a ring twisting machine. The spinning or twisting ring has a metal core and a metal coating applied to the core. The metal coating is designed as at least one hard chromium dispersion layer consisting of chromium with embedded hexagonal boron nitride.

Description

Spinning or twisting rings

The invention relates to a spinning or twisting ring for a ring spinning machine or a ring twisting machine.

Spinning rings are used in so-called ring spinning machines and twisting rings are used in so-called ring twisting machines. For this, the spinning or twisting ring interacts with the mounted traveler. Driven by the thread supported by the traveler, the traveler rotates at high speed on the upper side of the spinning ring, the so-called ring flange, which leads to high stresses on the contact surfaces of the spinning ring. For this reason, particular attention is paid to the properties of this surface in the production of spinning or twisting rings. Rings for ring spinning machines or ring twisting machines must not only have a precise machined shape, but also have an optimal surface suitable for these requirements, so that the traveler that rotates around the ring at high speed The result is a quiet and as low-wear rotation as possible. Due to the rapid rotation of the traveler on the spinning ring, local temperatures of more than 400° C. may occur, which place additional demands on the surface properties of the spinning ring.

To secure the spinning or twisting ring in the machine, a ring neck wall terminating in a bottom flange is provided. The ring flange and the bottom flange, or the ring neck wall without a bottom flange, can be produced in various designs, each of which is adapted in shape and geometry to the requirements of the respective machine. Therefore, spinning rings or twisted steel rings are collectively referred to as spinning rings in terminology.

Various methods are known from the prior art for coating or treating the surface of spinning rings. For example WO99/51802 describes the application of hard chrome coatings. Hard chrome coatings are applied to components by electrolytic chrome plating, mostly for wear protection. US 2970425 also discloses a surface coating for spinning rings with an electrolytically applied chromium layer. The disadvantage of this design of the hard chrome coating of the spinning ring is that, although a hard and low-wear surface results, the running characteristics of the spinning ring depend on the fiber lubrication on the surface of the ring film, the fiber lubricating film is caused by the yarn sliding on the traveler.

The object of the present invention is to provide a spinning ring which has a surface which exhibits only a low running resistance to the traveler independent of a fiber lubricating film.

This object is achieved by the features in the characterizing parts of the independent claims. For this purpose, a new type of metal coating is provided for the metal core of the spinning ring or twisting ring, wherein the metal coating is designed as at least one hard chromium dispersion layer, which layer consists of embedded Chromium composition of hexagonal boron nitride.

Particles consisting of hexagonal boron nitride are embedded in a hard chromium dispersion layer applied to the core. Statistically, among the dispersed particles composed of hexagonal boron nitride distributed in the hard chromium dispersion layer, some particles always exist on the surface of the hard chromium dispersion layer. Hexagonal boron nitride is the so-called "white graphite". White graphite is a material with very excellent lubricating properties combined with the highest temperature resistance of all lubricants up to 600°C. Thus, the exposed hexagonal boron nitride provides a lubricating material on which the traveler can slide with low wear. Running properties can thus be determined independently of the presence of a fiber lubricating film formed by the yarn.

The coating method is essentially like the known electrolytic hard chrome plating process in a corresponding bath. In addition to the usual hard chromium plating process, a dispersant (in this case hexagonal boron nitride) and other chemicals are added to the bath. The effect of these other chemistries is to cause the hexagonal boron nitride to dissolve better in the bath and remain in suspension, thereby allowing better intercalation into the growing hard chromium layer. Dispersion coatings of this type with proportions of up to 40% of dispersed substance are known from electroplating. The dispersed solution is maintained agitated in the bath by means of a stirrer. As in the case of simple hard chromium coatings, the final result is only influenced by the control of the parameters current intensity and bath temperature (and stirring speed). During the coating process, the spinning rings to be coated are each fastened in a clamping manner on the support.

Typically, the entire spinning ring is immersed in a coating bath and coated, except for the contact points where the spinning ring is fixed. However, it is also conceivable to confine the coating of the metal core to and around the contact surface of the traveler in the direction of the spinning ring by means of a corresponding mode of operation or clamping of the spinning ring. In this manner of operation, parts of the metal core are not provided with a hard chromium dispersion layer.

In another embodiment, the metal coating comprises a layer of hard chromium disposed directly on the metal core, wherein a dispersion layer of hard chromium is applied on the first layer of hard chromium. This method of operation increases the stability of the hard chromium dispersion layer, since the hard chromium dispersion layer is supported by the underlying hard chromium coating. This arrangement also enables a thinner hard chromium dispersion layer concept than would be possible without the use of a hard chromium layer.

In the case where the metallic coating consists of a hard chromium layer with a hard chromium dispersion layer at least partially located thereon, it is also possible to provide the hard chromium dispersion layer only to part of the steel rings by a corresponding procedure. Again, it is not absolutely necessary to provide a hard chrome layer over the entire core.

Advantageously, the thickness of the hard chrome dispersion layer on the contact surface is 0.001-0.060 mm. In a preferred solution, the thickness of the hard chromium dispersion layer is designed to be 0.020-0.040mm.

In order for the traveler to run quietly on the spinning ring, the surface of the spinning ring must be as hard and smooth as possible. Advantageously, the surface hardness of the surface of the hard chrome dispersion layer is HV800-1200 as measured by Vickers0.05. The surface roughness Ra is advantageously at most 0.0003 mm.

In order to obtain a favorable relationship between wear resistance and lubricating properties, the embedding rate of hexagonal boron nitride in the hard chrome dispersion layer is 1-30%, preferably 20-30%.

The average particle size of the hexagonal boron nitride embedded in the hard chromium dispersion layer is 0.0005-0.010mm. The purity of the hexagonal boron nitride used for the coating is greater than 97%.

To achieve the corresponding effect of the hexagonal boron nitride embedded in the hard chromium dispersion layer, the specific surface area of the hexagonal boron nitride used for the coating is 4-30 m ² /g.

The metal core of the spinning ring is advantageously made of steel, in particular heat-treated steel. Spinning rings have particularly good properties if the hard chrome dispersion layer is polished. Small irregularities in the coated surface can thus be eliminated.

In another variant, the core of the ring has a polished surface before applying the hard chromium dispersion layer. Here, the core can also be coated with a copper or nickel layer, which is then itself polished and the hard chromium dispersion layer is arranged thereon. Such a nickel or copper layer above the core and below the hard chromium dispersion layer is particularly advantageous for applications of the steel ring under corrosive conditions. The hard chromium dispersion layer applied on the polished surface has a very smooth surface, which results in a very quiet running of the traveler on such hard chrome-plated rings.

Claims (12)

1. A steel ring for a ring spinning machine or a ring twisting machine, having a metal core and a metal coating applied to the core, characterized in that the metal coating is designed as at least one layer A hard chromium dispersion layer consisting of chromium with embedded hexagonal boron nitride. 2. A steel ring according to claim 1, characterized in that the metal coating is applied only on part of the metal core. 3. Steel ring according to claim 1 or 2, characterized in that said metallic coating comprises a hard chrome layer arranged directly on the metal core, wherein said hard chromium dispersion layer is applied on the first hard chromium layer. 4. A steel ring according to any one of the preceding claims, characterized in that the hard chromium dispersion layer has a thickness of 0.001-0.060 mm. 5. A steel ring according to any one of the preceding claims, characterized in that the hard chrome dispersion layer has a surface hardness HV of 800-1200 and a surface roughness Ra of at most 0.0003 mm. 6. The steel ring according to any one of the preceding claims, characterized in that the hexagonal boron nitride embedding rate in the hard chrome dispersion layer is 1-30%, preferably 20-30%. 7. A steel ring according to any one of the preceding claims, characterized in that the average grain size of the hexagonal boron nitride is 0.0005-0.010 mm. 8. Steel ring according to any one of the preceding claims, characterized in that the purity of the hexagonal boron nitride is greater than 97%. 9. Steel ring according to any one of the preceding claims, characterized in that the specific surface area of the hexagonal boron nitride is 4-30 ^m2 /g. 10. Steel ring according to any one of the preceding claims, characterized in that the metal core is made of steel, in particular heat-treated steel. 11. Steel ring according to any one of the preceding claims, characterized in that the hard chromium dispersion layer is polished. 12. A steel ring according to any one of the preceding claims, characterized in that a nickel or copper layer is provided on the core, on which the hard chromium dispersion layer is arranged.