Spinning or twisting rings and associated ring / travellers and ring / traveller systems

Abstract

The present invention relates to a spinning ring (8) for a ring spinning or ring twisting machine, comprising a web (15) and a ring flange (14), the ring flange (14) consisting at least in part of a sintered tungsten material containing at least 90% tungsten. Furthermore, the present invention relates to a ring / traveler system comprising a ring traveler consisting of HSS steel.

Description

[Technical field]

[0001] The invention relates to a ring and a ring / traveler system for a ring spinning machine or a ring twisting machine. The ring is used as a spinning ring in a so-called ring spinning machine or as a twisting ring in a so-called twisting machine. As a result, the spinning ring and the twisting ring are grouped under the concept of "spinning ring". The spinning ring cooperates with a ring traveler placed thereon. The ring traveler is driven around by the thread held by the ring traveler and rotates at high speed against the upper side of the spinning ring, the so-called ring flange. This results in high loads on the contact surface between the ring traveler and the ring flange of the spinning ring. To fix the spinning ring in the machine, a web is provided which continues to the ring flange. This web can end in a base flange. The ring flange and the base flange, or the web in the absence of a base flange, can be made in various configurations and, in each case with regard to form and geometry, are made to the requirements of the corresponding machine and of the defined structure for fixing the spinning ring. The spinning ring is held in the machine in a so-called ring frame.

[0002] During operation, friction between the spinning ring and the ring traveler heats up the contact surfaces and thus also the yarn. The rapid rotation of the ring traveler against the spinning ring can locally generate temperatures of over 400° C., which sets operational limits for the ring / traveler system. Due to this mechanical situation, for today's typical ring diameters, the ring traveler cannot rotate at a speed higher than 30,000 revolutions per minute, so as not to damage the ring traveler or the yarn. With the improvement of the spinning ring and ring traveler structure, this speed is being increasingly increased, and today the maximum value for reliable spinning has reached about 42 m / s for cotton and about 32 m / s for polyester. Developments in the field of materials have had little impact on the substrates of the spinning ring and the ring traveler, but rather on the surfaces of both. The development of substrates for the spinning ring and the ring traveler has hardly been taken into account since the invention of the ring frame in the 19th century. Still, the customary material for both components is hardened carbon steel. Many different coatings for the spinning ring and the ring traveler have been developed. These coatings have already resulted in a significant increase in the service life of the components. Nevertheless, no significant increase in the speed of the ring traveller has been achieved by the coatings. Although the sliding properties have been improved by special coatings, at least in the region of the contact surfaces, and thus the service life has indeed been increased, an increase in the number of rotations of the ring traveller has hardly been achieved.

[0003] From the prior art, different configurations of coatings of spinning rings or ring travelers are known. For example, EP 1 066 419 A1 discloses a traveler coated with phosphate. This achieves less wear of the ring traveler against the ring. EP 3 052 684 A1 discloses a spinning ring with a chromium coating incorporating boron nitride. This also results in less wear of the ring traveler. US 200020162315 A1 discloses a nitrided traveler. By nitriding, higher wear resistance and improved sliding properties are achieved. US 4 677 817 A1 discloses a ring traveler coated with ceramic in order to reduce wear and increase the service life. Furthermore, US 2 970 425 A1 discloses a spinning ring coated with nickel. This results in a uniform surface and thus a reduced coefficient of friction.

[0004] A reduction in wear of one of the components, as shown in the prior art, can be achieved relatively easily, as this component (e.g. the spinning ring) must be coated with as hard a layer as possible or must be made from an extremely hard material. This has the disadvantage that the other component (e.g. the ring traveler) wears out even more quickly. In this case, the temperature of the friction points or contact surfaces has a detrimental effect. This temperature is higher in the ring traveler than in the spinning ring, which therefore accelerates the wear of the ring traveler, despite the hardest coating.

[0005] The object of the present invention is therefore to provide a spinning ring which allows a longer service life of the ring traveller at present-day speeds and which improves the upper limit to be achieved for the ring traveller speed.

[0006] It is also an object of the present invention to provide a ring / traveler system which allows an increase in the speed limit of the ring traveller above 50 m / s (for cotton).

[0007] This problem is solved by a spinning ring and a ring / traveler system having the features of the claims.

[0008] To solve the problem, a spinning ring for a ring spinning or twisting machine is proposed, which comprises a web and a ring flange, which ring flange is at least partially made of a tungsten sintered material containing at least 90% tungsten. By forming the ring flange partially with a tungsten surface, a series of advantageous properties are obtained compared to surfaces known from the prior art, for example made of steel, chromium, chromium carbide, nickel phosphorus and others. The tungsten grains forming the sintered material have a hardness of about 450 HV. This prevents abrasive wear on the harder ring traveler, but the hardness is high enough so that it can withstand abrasive wear well itself. Today's conventional spinning ring surfaces reach hardnesses of up to 1000 HV. This leads to high wear of the ring traveler. Furthermore, the tungsten grains have a high thermal conductivity of about 180 W / mK, which is almost twice as high as conventional materials and coatings. The increased thermal conductivity leads to improved heat dissipation and therefore cooling of the spinning ring surface. Tungsten granules also have a melting temperature of about 3400°C, compared to about 1900°C for conventional materials. The high melting temperature reduces the tendency for microwelding, which at least delays the destruction of the sliding surface.

[0009] When tungsten sintered material is exposed to dry friction, tungsten oxide is formed. This tungsten oxide is powdery, soft, easily meltable and has a weak adhesion to the substrate. This results in a self-lubricating effect that contributes to improving the sliding properties. In contrast, in conventional coated spinning rings, the self-lubricating effect does not occur during dry friction, because in chromium-coated spinning rings, for example, the chromium oxide formed is solid and hard, forming a strongly adhering continuous coating on the chromium surface.

[0010] Under these circumstances, the use of spinning rings made of sintered tungsten material has a positive effect on the wear of all known ring travelers. The degree of improvement that can be achieved varies for different ring traveler surfaces. The least improvement can be seen with the use of nickel-plated ring travelers. For uncoated steel ring travelers made of carbon steel, nitrided ring travelers and CVD-coated ring travelers (CrC, TiC coating), in addition to the improved wear properties, speed advantages of more than 10-15% could be obtained.

[0011] Preferably, the entire ring flange is made of tungsten sintered material containing at least 90% tungsten. The construction of the entire ring flange instead of a limited insert in the ring flange simplifies the manufacture of the spinning ring.

[0012] In an alternative embodiment, the spinning ring comprises a base flange on the side of the web opposite the ring flange. There are different construction forms of spinning rings, right up to spinning rings with two ring flanges. The construction of the spinning ring with a web or with a web and a base flange depends on the construction of the fixation of the spinning ring in the spinning machine or spin twisting machine.

[0013] Preferably, the tungsten sintered material is W97Ni2Fe. As tungsten sintered alloy, essentially any available W-Ni-Fe sintered material may be used. However, the tungsten sintered alloy may have a density of 18.5 g / cm 3 It has been found that the best results can be obtained using the material W97Ni2Fe1, which has a density of 1.0.

[0014] It is furthermore advantageous if the base flange and / or the web are made of copper or a copper alloy, which, when used as a spinning ring, provides high thermal conductivity, good flexibility in dynamic operation and corresponding dimensional stability. This also allows the parts of the spinning ring made of tungsten sintered material to be attached, preferably by a brazing process, to the ring flange or web.

[0015] In certain applications, it may be advantageous if the base flange and / or web are made of aluminum bronze, preferably nickel aluminum bronze (CuAl10Ni5Fe4). Such spinning rings according to the embodiments of the invention can be produced particularly inexpensively and at the same time are distinguished by high corrosion resistance and mechanical capabilities as well as a sufficiently high thermal conductivity. Such material pairing also increases the visual recognizability of the ring traveler relative to the spinning ring. This generally applies to the embodiments of the spinning ring according to the invention with base flanges and / or webs made of copper or copper alloys. Such increased visual recognizability also simplifies the inspection and possibly the replacement of the ring traveler.

[0016] In certain applications it may be advantageous if the base flange and / or the webs consist of steel. Spinning rings with good thermal conductivity can be obtained if the base flange and / or the webs consist of carbon steel, in particular 100Cr6. The use of ferritic special steel (1.2083) or duplex special steel (1.1462) for the base flange and / or webs of certain embodiments of the spinning ring according to the invention is also advantageous.

[0017] Preferably, the spinning ring is made entirely of tungsten sintered material, which contains at least 90% tungsten. This eliminates the need to manufacture a multi-part spinning ring and to bond the parts together, for example by a brazing process. In the manufacture of the entire spinning ring from tungsten sintered material, there is no fundamental difference between conventional steel spinning rings and spinning rings made of tungsten sintered alloy, since both are turned from blanks or manufactured by machining methods. Even in the case of a multi-part assembled spinning ring, the finished spinning ring is manufactured from a tubular blank that has been previously brazed together. However, unlike steel spinning rings, tungsten spinning rings are ready for use immediately after turning, and do not require the usual subsequent manufacturing processes, such as hardening, rubbing, polishing and chrome plating.

[0018] Furthermore, a ring / traveler system for a ring spinning or ring twisting machine is proposed, which comprises a spinning ring according to the above description and a ring traveler made of wire made of high speed steel (HSS), the ring traveler having a minimum hardness of 60 HRC. To achieve a maximum increase in the speed of the ring traveler, it is necessary to reduce the wear of the ring traveler without increasing the wear of the spinning ring or vice versa. This means that the contact surface of the spinning ring and the contact surface of the ring flange, and thus both friction surfaces, must be considered as a pair and optimized. This optimization includes not only the matching of the surface hardness of the components, but also other aspects, such as improving the heat dissipation from the friction point or chemical processes that may be initiated during friction (e.g. oxidation). The increase in the number of revolutions or speed of the ring traveler that can be achieved by optimization leads to a corresponding increase in the productivity of the spinning machine.

[0019] HSS ring travelers may be manufactured from any known high speed steel that exists in wire form. The ring traveler manufacturing is similar to the conventional ring traveler manufacturing from carbon steel, with the difference that the annealing, quenching and tempering processes are carried out under different conditions. For each HSS material, known hardening parameters specific to the material must be applied. The resulting base hardness is in the range of 850-1000 HV, depending on the high speed steel used. HSS ring travelers basically do not require coating and are ready for use after rubbing and polishing.

[0020] The advantage of HSS travellers over carbon steel travellers is mainly due to their significantly higher hot hardness. Hardened carbon steels soften fairly quickly after about 300°C, whereas hardened high speed steels maintain their initial high hardness up to about 550°C. During spinning operations, the temperature at the ring traveller friction surface is usually above 300°C. HSS steels therefore extend the usability of ring travellers to higher speeds. However, even in the temperature range below 300°C, HSS steels offer significantly higher hardness and strength than carbon steels. Since high speed steels are not as brittle as carbon steels at maximum hardness, HSS ring travellers can have a hardness of more than 200 HV more than conventional ring travellers even at room temperature. Carbon steel ring travellers must not be harder than 700 HV, because otherwise they would break when fitted onto the spinning ring. In contrast, the HSS ring traveller breaks only after a hardness of approximately 950 HV when placed over the spinning ring.

[0021] As with the tungsten spinning rings compared to conventional spinning rings, the HSS ring traveler actually outperforms all conventional carbon steel ring travelers when used in combination with all possible spinning rings. However, even here the maximum effect was only achieved with the tungsten rings. The following examples of use will show how much speed increase was achieved in each individual case.

[0022] Preferably, the high speed steel corresponds to material 1.3343 according to DIN EN ISO 4957 (2018-11) having the material designation HS6·5-2C. The use of this material has proven to be particularly advantageous.

[0023] The combination of a spinning ring made of sintered tungsten material and a ring traveler made of high speed steel (HSS ring traveler) enabled an increase in the ring traveler speed of more than 20%.

[0024] The extent to which speed increases could be achieved in the individual cases of combinations of spinning rings with ring flanges made at least partially from sintered tungsten material (tungsten spinning rings) with conventional ring travelers is shown by the following use examples, the names of which are taken from the Applicant's product catalog and correspond to commercially available ring travelers.

[0025] Prior to the start of a test series, the corresponding ring travelers of all spinning rings were run-in at low speeds (23-34 m / s) for several hours. A test series consisted of several identical tests, where each subsequent test was carried out at a somewhat higher speed (ring traveler revolutions) within the test series. The duration of one test per speed and ring traveler was 1 hour (a new ring traveler was used for each test). To determine the degree of wear, all ring travelers were weighed before and after the test (measurement accuracy of about 0.01 mg). During the test series, the speed was increased stepwise by 0.6 m / s in one step. As a reference point for comparison, a defined scale of ring traveler wear of 0.2 mg was established, and ring travelers with a wear greater than 0.2 mg were considered worn. The maximum possible speed limit was set at the ring traveler speed at which the first ring traveler in the series was worn out during the 60-minute test. No measurable wear of the spinning rings was observed in all tests. All use cases correspond to laboratory tests on a 16-spindle spinning machine from SER.MA.TES. In all tests, the new components (tungsten spinning ring and / or HSS ring traveler) were tested simultaneously together with a geometrically identical reference component based on the prior art. This allowed for a direct comparison between the conventional and the new components under the same conditions. The combined tungsten spinning ring consisted of a ring flange made of sintered material W97Ni2Fe1 brazed to a copper web. The HSS ring traveler was made of high speed steel 1.3343 (M2). The maximum achievable ring traveler speed corresponds to the speed at which the ring traveler experiences the same wear as the reference ring traveler speed in the spinning ring / ring traveler pairing to be compared within the same operating time.

[0026] Example 1 A tungsten spinning ring was compared to a chrome plated steel spinning ring for use with a carbon steel uncoated ring traveller. Spinning ring type: T flange ring φ47×38 Ring traveler type: C1ELMudrISO35.5mg Spinning parameters: cotton, Ne30, twist=1000, not dense Reference ring traveler speed in steel spinning rings: 20,000 rpm (39.8 m / s) Maximum ring traveler speed for tungsten spinning rings: 23,300 rpm (46.3 m / s) This results in a 16.3% increase in speed and therefore productivity.

[0027] Example 2 A tungsten spinning ring was compared to a chrome plated steel spinning ring for use with a carbon steel nitrided ring traveller. Spinning ring type: T flange ring φ47×38 Ring traveler type: C1SELudrISO31.5mg Spinning parameters: cotton, Ne30, twist=922, dense Reference ring traveler speed in steel spinning rings: 22,000 rpm (43.8 m / s) Maximum ring traveler speed for tungsten spinning rings: 25,300 rpm (50.3 m / s) This results in a 14.9% increase in speed and therefore productivity.

[0028] Example 3 The use of a tungsten spinning ring with an HSS ring traveler was compared to the use of a chrome plated steel spinning ring with an uncoated carbon steel ring traveler. Spinning ring type: T flange ring φ47×38 Ring traveler type: C1ELudrISO18.0mg Spinning parameters: cotton, Ne46, twist=1000, not dense Reference ring traveler speed in steel spinning rings: 22,000 rpm (43.8 m / s) Maximum ring traveler speed for HSS ring travellers on tungsten spinning rings: 27,000 rpm (53.7 m / s) This results in a 22.6% increase in speed and therefore productivity.

[0029] Example 4 The use of a tungsten spinning ring with an HSS ring traveler was compared to the use of a chrome plated steel spinning ring with an uncoated carbon steel ring traveler. Spinning ring type: T flange ring φ47×38 Ring traveler type: C1MMudrISO63.0mg Spinning parameters: cotton, Ne20, twist=705, not dense Reference ring traveler rotation speed: 14,300 rpm (28.4 m / s) Maximum ring traveler speed for HSS ring travellers on tungsten spinning rings: 17,300 rpm (34.4 m / s) This results in a 21.1% increase in speed and therefore productivity.

[0030] The invention is explained below on the basis of exemplary embodiments and is explained in more detail by means of the drawings. [Brief description of the drawings]

[0031] [Figure 1] FIG. 2 is a schematic diagram of a spinning unit of a ring spinning machine. [Diagram 2] FIG. 1 is a schematic diagram of a spinning ring including a ring traveler. [Diagram 3] FIG. 3 is an enlarged view equivalent to FIG. [Figure 4] Schematic diagrams of the second and third embodiments of the spinning ring.

[0032] FIG. 1 shows a schematic representation of a spinning unit of a ring spinning machine. Today's ring spinning machines have up to 2,000 or even more such spinning units. In a ring spinning machine, a fiber bundle, the so-called sliver 1, is fed to a drafting device 2. The drafting device 2 stretches the sliver 1 to form a yarn 3. The illustrated drafting device 2 is a so-called apron drafting device, which is normally used for cotton. From the prior art, different constructions of the drafting device 2 are known, depending on the application. Downstream of the drafting device 2, the yarn 3 is guided via a yarn guide 4 to a ring traveler 10. After passing through this ring traveler 10, the yarn 3 is wound onto a twisting bobbin 5. This twisting bobbin 5 is rotated 6 by a drive 7. Due to this rotation 6 of the twisting bobbin 5, the ring traveler 10 is entrained by the yarn 3. This imparts a twist to the yarn 3, and thus a twisted yarn is formed. The ring traveler 10 is held by the spinning ring 8, so that the ring traveler 10 is forced to go around the twisting bobbin 5. The spinning ring 8 is held immovably by a ring frame 9.

[0033] FIG. 2 shows a schematic representation of a spinning ring 8 fitted with a ring traveler 10. The illustrated spinning ring 8 consists of a ring flange 14 and a web 15 which is connected to the ring flange 14. The web 15 is used to fasten the spinning ring 8 to the spinning machine. The ring traveler 10 is fitted over the ring flange 14 and partially surrounds it. In this case, the ring traveler 10 is formed so as to surround the ring flange 14 in such a way that, due to its shape, no falling of the ring traveler 10 from the ring flange 14 occurs, but the greatest possible freedom of movement of the ring traveler 10 relative to the ring flange 14 is obtained. Numerous shapes and configurations of the ring flange 14 and the ring traveler 10 are known from the prior art. Due to the rotational movement transmitted to the ring traveler 10 by the yarn 3, the ring traveler 10 rotates around the spinning ring 8 in the direction of the traveler rotation 11. This rotation also generates centrifugal forces 12 which act on the ring traveler 10. This centrifugal force 12 presses the ring traveler 10 against the inner surface of the spinning ring 8 or the ring flange 14 .

[0034] This situation is shown enlarged in Fig. 3. The ring traveler 10 slides along the spinning ring 8, whereby a contact surface 13 is created. At least in the region of this contact surface 13, care must be taken that the ring traveler 10 has good sliding properties with respect to the spinning ring 8. By a suitable material selection of the ring flange 14, at least in the region of the contact surface 13, the sliding pairing between the spinning ring 8 and the ring traveler 10 is promoted. In the region of the contact surface 13, the ring flange 14 is shown equipped with an insert 16 made of tungsten sintered material with at least 90% tungsten. This insert is connected to the ring flange by a brazing process to a base material, for example copper.

[0035] In FIG. 4, a schematic view of a second and a third embodiment of a spinning ring 8 according to the invention is shown. The drawing is divided into two parts, and in the left and right configurations, respectively, a spinning ring 8 is shown with a ring flange 14, a web 15 and a base flange 17 arranged on the side of the web 15 opposite the ring flange 14. The base flange 17 is used to fasten the spinning ring 8 to the spinning machine. In the right configuration, the ring flange 14 is made of a tungsten sintered material with at least 90% tungsten, while the remaining parts of the spinning ring 8, i.e. the web 15 and the base flange 17, are made of standard materials, for example copper, copper alloys, steel or light metals. The ring flange 14 is connected to the web 15 by a brazing or welding process. In contrast to this, in the left configuration, the entire spinning ring 8 is made of a tungsten sintered material with at least 90% tungsten.

[0036] The invention is not limited to the illustrated embodiments, but modifications within the scope of the claims are possible, as well as combinations of features even if illustrated in different embodiments. [Explanation of symbols]

[0037] 1 sliver 2 Draft device 3. Thread 4 Thread guide 5. Yarn Bobbin 6 Rotations 7 Drive unit 8. Spinning Ring 9 Ring Rail 10 Ring Traveler 11 Traveler Rotation 12 Centrifugal Force 13 Contact surface 14 Ring flange 15. Web 16 Insert 17 Foundation flange

Claims

1. A spinning ring (8) for a ring spinning machine or a ring twisting machine, comprising a web (15) and a ring flange (14), characterized in that the ring flange (14) is made at least in part of a sintered tungsten material containing at least 90% tungsten.

2. 2. Spinning ring (8) according to claim 1, characterized in that the entire ring flange (14) consists of a sintered tungsten material containing at least 90% tungsten.

3. 3. The spinning ring (8) according to claim 1 or 2, characterized in that the web (15) is provided with a base flange (17) on the side opposite the ring flange (14).

4. 3. Spinning ring (8) according to claim 1 or 2, characterized in that the tungsten sintered material is W97Ni2Fe1.

5. 4. Spinning ring (8) according to claim 3, characterized in that the base flange (17) and / or the web (15) consist of copper or a copper alloy.

6. Spinning ring (8) according to claim 5, characterized in that the copper alloy is an aluminum bronze, preferably a nickel aluminum bronze CuAl10Ni5Fe4.

7. 4. Spinning ring (8) according to claim 3, characterized in that the base flange (17) and / or the web (15) consist of steel.

8. 3. The spinning ring (8) according to claim 1 or 2, characterized in that the part of the spinning ring (8) made of tungsten sintered material is attached to the ring flange (14) or the web (15) by a brazing process.

9. 3. Spinning ring (8) according to claim 1 or 2, characterized in that the spinning ring (8) consists entirely of sintered tungsten material containing at least 90% tungsten.

10. A ring / traveler system comprising a spinning ring (8) according to claim 1 or 2 and a ring traveler (10) made of wire made of high speed steel (HSS), the ring traveler (10) having a minimum hardness of 60 HRC.

11. 11. The ring / traveler system according to claim 10, characterized in that the high speed steel (HSS) corresponds to material 1.3343 according to DIN EN ISO 4957 (2018-11) having the material designation HS6.5-2C.

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