WO2017037236A1

WO2017037236A1 - Open-end spinning rotor with a rotor cup made of a heat-treatable steel material

Info

Publication number: WO2017037236A1
Application number: PCT/EP2016/070723
Authority: WO
Inventors: Siegfried Krohmer; Bernd Loos
Original assignee: Maschinenfabrik Rieter Ag
Priority date: 2015-09-03
Filing date: 2016-09-02
Publication date: 2017-03-09
Also published as: DE102015114731A1

Abstract

An open-end spinning rotor (1) includes a rotor cup (3) made of a heat-treatable steel material. The rotor cup (3) has a fiber slide wall (4) and a fiber collecting groove (5). The rotor cup (3) has a chromium carbide layer (7) at least in the region of the fiber collecting groove (5) and/or the fiber slide wall (4). In a method for producing an open-end spinning rotor (1) with a rotor cup (3) made of a heat-treatable steel material, said rotor cup (3) having a fiber slide wall (4) and a fiber collecting groove (5), the rotor cup (3) undergoes a diffusion treatment, wherein a chromium carbide layer (7) is produced at least in the region of the fiber collecting groove (5) and/or the fiber slide wall (4).

Description

Open-end spinning rotor with a rotor cup made of usable

steel material

The present invention relates to an open-end spinning rotor having a rotor cup made of a heat-treatable steel material, wherein the rotor cup has a fiber slide wall and a fiber collecting groove.

From DE 31 44 383 A1 a spinning rotor for an open-end spinning machine made of heat-treatable steel is known, whose at least inner part has a surface layer which consists individually or in combination of iron carbide, iron boride, iron silicide or iron nitride. On this surface layer, a further, a foreign metal-containing, surface protective layer is applied, which may consist of zinc, nickel, oxide, phosphate or chromate. In this case, the first surface layer serves to provide a wear-resistant surface, while the second, applied thereto surface protection layer to protect the surface of the spinning rotor from corrosion.

Furthermore, EP 0 337 107 B1 discloses a steel spinning rotor in which at least the surfaces of the rotor cup which come into contact with the fibers and the thread have a borated surface layer and a nickel coating applied thereto. Again, the borated surface serves the wear protection, while the nickel layer is applied as corrosion protection. In addition, hard material grains can be incorporated into the nickel layer for wear protection. Between these two layers is an alpha-iron layer, which on the one hand serves as a bonding agent and on the other hand prevents damage to the borated surface layer and the nickel coating.

Although both inventions are spinning rotors with a wear-resistant surface and provide a solution for good spinning results, but it still have disadvantages. On the one hand, the processes for producing such spinning rotors prove to be expensive and, on the other hand, the boronization of the rotors used as wear protection can often not be carried out reliably.

Object of the present invention is thus to develop a spinning rotor, which is simple, inexpensive and process reliable to produce.

The object is achieved by an open-end spinning rotor with a rotor cup made of a heat-treatable steel material having the features of the independent patent claims 1 and 9.

The proposed open-end spinning rotor has a rotor cup made of a heat-treatable steel material, wherein the rotor cup includes a fiber slip wall and a fiber seed tube. The rotor cup has a chromium carbide layer at least in the area of the fiber collecting groove and / or the fiber sliding wall.

The chromium carbide layer provides a very hard surface in comparison with the known chloride layers, which offers very good wear protection, the spinning rotor nevertheless being suitable for high rotor speeds due to its production from a heat-treatable steel material. It has been shown that the comparatively smooth chromium carbide layer nevertheless ensures a certain degree of roughness, which ensures good entrainment of the fibers in the extended orientation. Nevertheless, the fibers adhere less strongly to the surface of the chromium carbide layer so that the fibers do not get stuck in the groove. If the fiber sliding wall is also provided with the chromium carbide layer, due to the comparatively smooth surface structure, the fibers are conveyed well and evenly into the groove. It has also proven to be advantageous that the chromium carbide layer has a continuous, ie substantially crack-free, and comparatively smooth surface provides. Dirt particles therefore find no liability and it can be prevented that accumulate dirt particles at certain points. Therefore, the chromium carbide layer leads to a strong reduction of rotor contamination in mixed fibers, but also in cotton, which has a more stable spinning process with long lasting consistent yarn quality result and reduces the maintenance effort for rotor cleaning.

The method of forming a chromium carbide layer by subjecting the rotor cup to diffusion treatment at least in the area of the fiber strand and / or the fiber tray describes a cost effective and easy way to provide the spinning rotor with a protective layer, since only a single chromium carbide layer is used Treatment is necessary. It is advantageous in this case that the chromium carbide layer which serves as wear protection already serves as a rust protection per se, which is why an additional nickel plating is not necessary, as in the previous spinning rotors.

Furthermore, it is advantageous if the rotor cup, at least in the area of the fiber collecting groove and / or the fiber sliding wall, has a maximum roughness depth between R _t 1 and R _t 10 or an average roughness depth between R _z 1, 6 and R _z 6 and / or an average surface roughness between R _a 0.2 and R _a 0.8. It has been found that with such values an optimum compromise is achieved between a roughness advantageous for the spinning process and a smooth surface which reduces the adhesion of soiling.

It is likewise advantageous if the chromium carbide layer has a layer thickness of at least 15 μιτι, preferably at least 18 μιτι and particularly preferably at least 20 μιτι, but preferably a layer thickness of 30 μιτι, preferably 25 μιτι does not exceed. As a result, a comparatively thin wear protection layer of high uniformity is obtained, which follows the contour of the blank very well, so that the spinning process is not influenced by the coating. The hardness of the chromium carbide layer should preferably have a hardness of at least 2000 HV. Due to the high hardness of the inchromated surface wear protection and thus the service life of a rotor is improved, so that even with comparatively thin layers very good results can be achieved.

In an advantageous embodiment of the invention, the chromium carbide layer is the only coating directly, d. H. without further surface treatment, applied to the surface of the rotor cup, in particular the Fasersammeirille and / or the Faserrutschwand. Since only one coating is present, such a spinning rotor can be produced very inexpensively and there is no distortion of the contour as in other methods.

It is advantageous if the rotor cup of the spinning rotor is produced as a turned part and the chromium carbide layer is applied directly to the surface of the rotating part, since the surface roughness can be adjusted well by the processing quality according to the requirements and with high processing quality no further surface treatment such as grinding or the like necessary is.

In order to enable a rust protection for the entire rotor cup, it is advantageous if at least one inner surface of the rotor cup is completely provided with a chromium carbide layer.

With regard to the method for producing the disclosed open-end spinning rotor, it is advantageous if the rotor cup is provided with a chromium carbide layer produced by diffusion at least in the area of the fiber collecting groove and / or the fiber sliding wall and this diffusion treatment is preferably carried out at a temperature of 900 ° C. 1200 ° C is performed. Since the chromium carbide layer is thereby firmly embedded in the steel of the basic Material diffused, the spinning rotor has improved heat dissipation.

It is likewise advantageous if the rotor cup is tempered after the diffusion treatment, in particular at a temperature between 400 ° C. and 550 ° C., over a period of 20 min-60 min.

It is furthermore advantageous if the chromium carbide layer is untreated, in particular unpolished, or in the method the rotor cup is no longer subjected to any further treatment after the diffusion treatment and / or after the tempering, in particular is not polished. Since the chromium carbide layer can be made even with a very high surface quality, which already has a reduced coefficient of friction, for example, a polishing of the surface is not required. Likewise, it is not necessary to apply an additional coating for corrosion protection, since the chromium carbide layer itself is already resistant to oxidation. Advantageously, the rotor cup is thus provided only with the untreated chromium carbide layer as the only coating.

Further advantages of the invention are described in the following exemplary embodiments. Show it:

FIG. 1 shows a sectional drawing of a spinning rotor with rotor shaft and rotor disk, in which only the fiber collecting lug has a chromium carbide layer,

Figure 2 is a sectional view of a spinning rotor with rotor shaft and rotor cup, in which the entire inner surface of the rotor cup has a chromium carbide layer, and

Figure 3 is a schematic representation of a microscopic

Micrograph of a chromium carbide layer. 1 shows a sectional view of a spinning rotor 1 with a rotor shaft 2 and a rotor cup 3, which has a rotor bottom 1 1, a Fasersammeirille 5 and a Faserrutschwand 4. In the spinning process, individual fibers enter the rotor cup 3 of the spinning rotor 1 through the opening 6. The fibers strike a fiber slipper wall 4 and from there, by means of the centrifugal force generated by the rotation of the spinning rotor 1, are guided to a fiber sliver groove 5, where they collect and form a fiber ring. The collected in the Fasersammeirille 5, individual fibers are finally deposited on a projecting into the spinning rotor 1 yarn end and are involved by the rotation of the spinning rotor in the generated, continuous thread. It is advantageous if the fiber sliding wall 4 of the spinning rotor 1 has a comparatively low roughness. Of the fiber slipper 4, the individual fibers with low frictional resistance in the direction of Fasersammeirille 5 are to be conducted. Arrived in the Fasersammeirille 5, the individual fibers are to be taken reliably by the rotation of the spinning rotor 1, for which a slightly higher roughness with a higher frictional resistance is advantageous.

In the present case, it is provided that the spinning rotor 1 is provided, at least in the fiber collecting groove 5, as shown in FIG. 1, with a chromium carbide layer 7, which serves to increase the hardness, corrosion resistance and wear resistance. The chromium carbide layer 7 is formed by inching the workpiece surface and has a thickness of between 15 μm and 30 μm, in particular between 20 μm and 25 μm, and a hardness of at least 2000 HV.

The process of inchrometering is based on a thermochemical diffusion process. In doing so, chromium-releasing substances, in particular halogen compounds of chromium, are allowed to act on the workpiece at temperatures between 900 ° C. and 1200 ° C. This can be done both in the powder process and in the gas phase or in salt baths. Due to the heat chromium can be diffused into the workpiece surface, so that a chromium-rich surface layer forms, which has a particularly good anchoring to the base material due to the fact that the layer predominantly penetrates into the base material. A spalling of the layer, as occurs in conventional nickel layers, is thus largely excluded.

In the spinning rotor 1 described here, a steel with a carbon content of> 0.2% C is used, so that the diffusing chromium forms a particularly hard and wear-resistant chromium carbide layer 7 with the carbon contained in the steel. To ensure that only the Fasersammeirille 5 inchroniert, while the remaining surface of the rotor cup 3 is covered with a suitable means. Similarly, the bore 8 for receiving the rotor shaft 2 is covered prior to the inchomation. After the diffusion treatment, the spinning rotor 1 is tempered for 30 minutes in another heat treatment.

Since the resulting chromium carbide layer 7 is comparatively thin and the rotor contour follows very accurately and with high uniformity without variations in the layer thickness, the coating does not affect the spinning results. At the same time, the chromium carbide layer 7 only has a very low tendency to crack under load, so that the spinning rotor 1 also has good spinning properties for a long time. It has also been shown that fibers adhere less strongly to the chromium carbide layer 7 and can easily escape from the fiber-collecting groove 5 with the spun fibers, so that the tendency of the fiber-collecting groove 5 to become soiled is reduced. This further contributes to a stable spinning process with long-term good yarn quality.

In contrast to the exemplary embodiment illustrated in FIG. 1, in the present spinning rotor 1, the entire inner surface 12 of the rotor cup 3 is provided with a chromium carbide layer 7. Depending on the chosen method for However, the whole surface of the spinning rotor 1 can be provided with the chromium carbide layer 7 for inchromatization. The thermochemical diffusion treatment is the same in this spinning rotor 1. However, only the bore 8 for receiving the rotor shaft 2 is covered here before the inchomization.

The fiber collecting groove 5 and the fiber sliding wall 4 have the same roughness in this spinning rotor 1. The chromium carbide layer 7 has proven to be optimal here, on the one hand not to hinder the sliding of the fibers on the fiber slipper 4 and still provide sufficient roughness in the fiber collecting groove 5. Due to the comparatively smooth surface in the region of the fiber slipper wall 4, the deposit of impurities is also reduced there, which likewise contributes to the spinning stability. In any case, the inner surface 12 of the spinning rotor 1, in particular the fiber collecting groove 5 and the Faserrutschwand 4, particularly well protected by the chromium carbide 7 both from wear by the abrasive action of the fibers and from corrosion.

After the diffusion treatment, the rotor cup 3 is preferably tempered at temperatures between 400 ° C and 550 ° C over a period of 30 minutes in both spinning rotors. Subsequently, the rotor shaft 2 can be mounted.

Finally, FIG. 3 also shows a schematic representation of a microscopic micrograph of a chromium carbide layer 7. The chromium carbide layer 7 shown has, for example, a layer thickness of 18 μιτι. It is within the chromium carbide 7 a dark gray base layer 9 with a layer thickness of about 15 μιτι and a light gray edge layer 10 with a layer thickness of about 3 μιτι recognizable. The dark gray base layer 9 has more than 80% of chromium carbides a higher concentration than the light gray surface layer 10 with only between 50% and 60% of chromium carbides. The hardness of the chromium carbide layer 7 thus decreases inwards even more, which further supports the particularly good wear properties of the spinning rotor 1.

The present invention is not limited to the illustrated and described embodiments. Variations within the scope of the claims are also possible.

LIST OF REFERENCES

Open-end spinning rotor

rotor shaft

rotor cup

Fiber slide wall

Fiber collecting groove

opening

chromium carbide

drilling

base layer

boundary layer

rotor base

palm

Claims

Patent claims

1 . Open-end spinning rotor (1) with a rotor cup (3) made of a heat-treatable steel material, wherein the rotor cup (3) has a fiber sliding wall (4) and a fiber collecting channel (5), characterized in that the rotor cup (3) at least in the region of the fiber collecting channel (5) and / or the fiber slipper wall (4) has a chromium carbide layer.

2. Open-end spinning rotor according to the preceding claim, characterized in that the rotor cup (3) at least in the area of the fiber collecting groove (5) and / or the fiber slide wall (4) a maximum surface roughness between R _t 1 and R _t 10 and / or has an average surface roughness between R _a 0.2 and R _a 0.8.

3. Open-end spinning rotor according to one of the preceding claims, characterized in that the chromium carbide layer has a layer thickness of at least 15 μηπ, preferably at least 18 μηι and more preferably at least 20 μηι.

4. Open-end spinning rotor according to one of the preceding claims, characterized in that the chromium carbide layer has a layer thickness of less than 30 μηπ, preferably less than 25 μηι.

5. Open-end spinning rotor according to one of the preceding claims, characterized in that the chromium carbide layer has a hardness of at least 2000 HV.

6. Open-end spinning rotor according to one of the preceding claims, characterized in that the chromium carbide layer directly on a surface of the rotor cup (3), in particular the Fasersammeirille (5) and / or the Faserrutschwand (4) is applied and the rotor cup (3) has no further coating.

7. open-end spinning rotor according to one of the preceding claims, characterized in that the rotor cup (3) is made as a turned part and the chromium carbide layer is applied directly to the surface of the rotary member.

8. open-end spinning rotor according to one of the preceding claims, characterized in that at least one inner surface (12) of the rotor cup (3) is completely provided with a chromium carbide layer.

9. open-end spinning rotor according to one of the preceding claims, characterized in that the chromium carbide layer untreated, in particular unpolished, is.

10. A method for producing an open-end spinning rotor (1) with a rotor cup (3) made of a heat-treatable steel material, wherein the rotor cup (3) has a Faserrutschwand (4) and a Fasersammeirille (5), characterized in that the rotor cup (3 ) is subjected to a diffusion treatment, wherein a chromium carbide layer is produced at least in the region of the fiber collection groove (5) and / or the fiber slide wall (4).

1 1. Method according to the preceding claim, characterized in that the diffusion treatment is carried out at a temperature of 900 ° C - 1200 ° C.

12. The method according to the preceding claim, characterized in that the rotor cup (3) is tempered after the diffusion treatment, in particular at a temperature between 400 ° C and 550 ° C is tempered.

13. The method according to any one of claims 10 - 12, characterized in that the rotor cup (3) after the diffusion treatment and / or after tempering no further treatment is subjected more, in particular not polished.