JP7390969B2 - Ring for spinning machine and its manufacturing method - Google Patents

Description

The present invention relates to rings for spinning machines, etc.

Almost the final step in the spinning process to make yarn from raw cotton is the spinning process, in which the roving obtained in the roving process is stretched to a predetermined thickness, twisted, and wound onto a bobbin. . Currently, the spinning process is mainly carried out using ring spinning machines. A ring spinning machine is a spinning machine that winds yarn through a traveler that slides on a ring that is supported by a ring rail and moves up and down.

By the way, in order to improve the productivity of the spinning process (particularly the spinning process), it is desired that the ring spinning machine be able to operate continuously at high speed for a long period of time. Therefore, there is a need to improve or enhance the sliding characteristics between the ring and the traveler under non-liquid lubrication (dry state) to extend their service life (lengthen their replacement life). A proposal related to this can be found, for example, in Patent Document 1 below.

Special Publication No. 2002-510755 Patent No. 5910569 Patent No. 5994721 Patent No. 6149838

Patent Document 1 proposes coating the sliding surface of the ring with hard chromium. Patent Document 2 proposes forming a periodic structure consisting of a recessed part and a flat part on the sliding surface of a ring. Patent Document 3 proposes forming microcracks (recesses) on a chromium plating layer provided on the sliding surface of a ring. Patent Document 4 proposes forming large recesses (dents) and small recesses (microcracks) on a chromium plating layer provided on the sliding surface of a ring.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a new ring for spinning machines, etc., which can improve sliding characteristics.

The inventor of the present invention conducted extensive research to solve this problem, came up with a new texture to be formed on the sliding surface of the ring, and actually confirmed its effectiveness. By developing this result, we have completed the present invention described below.

《Ring for spinning machine》
(1) The present invention is a ring that is used in a spinning machine that winds yarn through a traveler, and has a sliding surface on which the traveler slides, and the sliding surface has a plurality of recesses and a ring between the recesses. The ring has a texture having curved convex portions between adjacent convex portions, and the convex portions are rings for spinning machines having a radius of curvature of 40 to 400 μm.

(2) According to the ring for a spinning machine (also simply referred to as a "ring") of the present invention, even in a dry environment, a long sliding distance (operating time) can be achieved with low friction between the sliding part of the ring and the traveler. Can be secured. As a result, the life of the rings and travelers can be extended, the spinning machine can be operated at high speed for a long period of time, and the productivity related to spinning can be improved.

(3) Although the reason why such an effect is obtained is not necessarily certain, it is currently assumed as follows. Fibers (mainly cellulose) generated from the yarn during spinning intervene between the sliding parts and contribute to reducing friction and suppressing wear between the ring and the traveler. The recesses in the texture temporarily trap (reserve) the fibers and stabilize such sliding conditions.

The space between the recesses according to the present invention is not a mere flat surface as in the conventional case, but a convex portion curved with a predetermined curvature. Sliding between the ring and the traveler is more likely to occur at the smooth convex portion (particularly near the top). Further, the fibers captured in the recesses are guided to the curved surfaces of the protrusions that smoothly extend from the recesses, and are easily supplied to the sliding gap near the protrusions. These factors act synergistically to improve the sliding characteristics between the ring and the traveler (lower friction, less wear, etc.), ensuring a long sliding distance with low friction. It is thought that it has become.

《Method for manufacturing rings for spinning machines》
The present invention can also be understood as a method for manufacturing rings for spinning machines. For example, the present invention includes a first step of forming a plurality of recesses on the surface to be treated of the ring, and a second step of rounding the periphery of the recesses and/or the adjacent areas (surfaces) of the recesses. The present invention may also be a method for manufacturing a ring for a spinning machine that provides a moving surface.

"others"
(1) In this specification, the case where the texture is provided on the ring is illustrated, but the texture may be provided on the traveler. At this time, texture may be provided on both the ring and the traveler. Therefore, the present invention can be understood not only as a ring for a spinning machine, but also as a traveler for a spinning machine, and further as a ring/traveler system for a spinning machine. Furthermore, the present invention may be understood as a spinning machine (including a spinning frame as well as a roving frame) equipped with such a ring and/or a traveler.

(2) "x to y" as used herein includes a lower limit x and an upper limit y, unless otherwise specified. A new range such as "a to b" can be established by setting any numerical value included in the various numerical values or numerical ranges described herein as a new lower limit or upper limit. Furthermore, unless otherwise specified, "x to y μm" as used herein means x μm to y μm. The same applies to other unit systems.

They are a perspective view (a) of a ring as an example, a partially enlarged perspective view (b) thereof, and a schematic sectional view (c) showing a state of sliding contact between the ring and the traveler during spinning. FIG. 2 is a plan view showing an example of a substrate surface on which a depression is formed by laser processing. FIG. 3 is a schematic diagram showing a state of lapping processing, which is an example of polishing processing. FIG. 3 is a schematic cross-sectional view illustrating a state after laser processing and a state after lapping processing. It is a profile illustrating a surface cross section after lapping. FIG. 2 is a schematic diagram showing the state of a ball-on-disc friction test (BOD test). It is a graph illustrating the relationship between sliding distance and friction coefficient obtained by a BOD test. It is a scatter diagram which shows the relationship between the radius of curvature of a convex part and the sliding distance where a friction coefficient is 0.6 or less. It is a bar graph illustrating the relationship between the sliding distance and the wear depth of the ball (the amount of wear on the mating material). This is a photograph (SEM image) obtained by observing the textured surface of Sample 6 after the friction test using a scanning electron microscope (SEM). It is a scatter diagram showing the correlation between the sliding distance of the BOD test (basic test) and the sliding distance of the actual machine test. It is a graph showing the relationship between sliding distance and friction coefficient (another example) obtained by a BOD test. This is a SEM image of the textured surface after the test.

One or more components arbitrarily selected from the present specification may be added to the components of the present invention described above. The content described in this specification may apply not only to products (such as rings for spinning machines) but also to manufacturing methods as appropriate.

《Ring Traveler》
A ring 11 and a traveler 12 used in a ring spinning machine are shown in FIGS. 1(a) to 1(c). The ring 11 has a flange 11a having a substantially T-shaped cross section. The traveler 12 has a substantially C-shaped cross section and is slidably engaged with the flange 11a. Both the ring 11 and the traveler 12 are made of steel, and the ring 11 has a (hard) chromium plating layer 13 on the surface (sliding surface) of the flange 11a. The chromium plating layer 13 has a thickness of about 3 to 20 μm, more preferably about 10 to 15 μm.

As shown in FIG. 1(c), the yarn Y sent out from the draft part (schematic diagram) passes through the traveler 12 and is wound onto a bobbin (schematic diagram) that rotates at high speed. At this time, the traveler 12 slides on the chrome plating layer 13 of the flange 11a due to the winding tension of the thread Y. Although the traveling attitude of the traveler 12 may change somewhat depending on the rotational speed, during normal spinning operation, the traveler 12 comes into sliding contact with the inner lower part of the flange 11a, as shown in FIG. 1(c). Note that even during normal spinning operation, the maximum rotational speed of the spindle increases to about 25,000 rpm.

"texture"
(1) The texture is preferably provided on at least a portion of the sliding surface between the ring and the traveler sliding on the ring. For example, when a ring is provided with a texture, the texture may be provided on the entire surface of the ring, but it is preferable that the texture be provided at least on the inside (or even lower) surface of the flange.

(2) The texture is made up of a plurality of concave portions and convex portions. The area (size) in which the texture is formed is adjusted depending on the sliding behavior between the ring and the traveler. For example, the texture may be present in areas of the ring that are primarily in contact with the traveler. The portion is preferably formed into an annular shape with a width of 1 to 5 mm, or more preferably 2 to 3 mm.

The concave portions (or convex portions) formed in the texture preferably exist at a density of, for example, 15 to 25, or more preferably 17 to 22, within the field of view (263 μm x 350 μm) observed under a microscope. The presence or absence of a recess is determined, for example, by whether or not its approximate center (the deepest part of the longitudinal section (the section perpendicular to the sliding area)) is within the field of view.

The plurality of recesses may be arranged regularly or irregularly. The regular arrangement may be, for example, a checkerboard pattern or a zigzag pattern (a state in which rows are alternately staggered). Each recess may have the same shape or a different shape. The recesses having the same shape may have the same size or different sizes.

The interval between adjacent recesses is the distance between the deepest parts of each recess. For the plurality of recesses in the field of view mentioned above, draw a straight line (any one line) passing through their approximate centers, and calculate the arithmetic average value of the adjacent intervals (distance between centers) on that straight line as the "adjacent interval". (simply referred to as "pitch"). The pitch determined in this way may be, for example, 40 to 100 μm, 45 to 90 μm, or even 55 to 80 μm. It is preferable that the recesses are provided regularly. Note that each dimensional accuracy (tolerance) referred to in this specification is approximately ±20% of the target dimension.

The shape of the opening of the recess (the shape of the outermost periphery) may be circular, elliptical, rectangular, or the like. A typical example thereof is a circular shape. The size of the recess is indexed by the longest width before forming the curved protrusion (simply referred to as a "recess"). Regarding the plurality of recesses within the above-mentioned field of view, the size of the recess is indexed by the arithmetic average value of the longest width of each recess (regardless of whether the recess is circular or not, simply referred to as "recess diameter"). The diameter of the depression may be, for example, 10 to 80 μm, and more preferably 30 to 60 μm.

Similarly, the depth of the recess is indexed by the depth from the periphery to the deepest part (deepest length) of the recess before the formation of the convex part. Regarding the plurality of recesses within the field of view described above, the depth of the recess is indexed by the arithmetic mean value of the deepest length of each recess (simply referred to as "recess depth"). The depth of the depression may be, for example, 2 to 12 μm, more preferably 4 to 10 μm.

The radius of curvature of the convex portion is determined from the curve near the apex (the outermost surface) of the concave portion, based on the longitudinal section of the concave portion. Specifically, the radius of the circular arc that approximated the curve near the apex was taken as the radius of curvature of the convex portion. Arc approximation was performed using the least squares method. The apex of the convex portion was set as the point of contact with a plane (reference plane) around the convex portion. The reference plane is, for example, a plane that touches (or is closest to) three or more recesses (opening edges) around the protrusion.

Regarding the plurality of convex portions within the above-mentioned field of view, the arithmetic mean value of the radius of curvature of each convex portion appearing on one longitudinal section passing through the center of the plurality of concave portions is referred to as the “radius of curvature” in this specification. shall be. The radius of curvature determined in this way is preferably, for example, 40 to 400 μm, 45 to 370 μm, 50 to 330 μm, and further 80 to 280 μm.

(3) Various methods can be used to form the texture. The texture may be formed, for example, through a first step of forming a plurality of depressions on the treated surface of the ring, and a second step of rounding the periphery of the depressions and/or the surface between adjacent depressions.

The first step is performed, for example, by irradiating a high-energy beam (eg, laser, electron beam, etc.) onto the surface to be treated of the base material that will become the ring or traveler. For example, a pulsed laser with a short pulse width (femtosecond, picosecond, nanosecond, etc.) can be used as the high-energy beam. As an example, it is preferable to use a nanosecond pulse laser having a pulse width of, for example, 1 to 100 ns, or even 5 to 50 ns.

The second step is performed, for example, by polishing the surface on which the depressions were formed in the first step. The polishing may be mechanical polishing or chemical polishing (etching, etc.). Mechanical polishing using free abrasive grains is performed by jetting processing (shot blasting, shot peening, etc.), barrel processing, lapping, polishing, etc. Polishing uses appropriate abrasive grains (material, grain shape, grain size, etc.) and method (tools, equipment, etc.) may be selected. The second step may be performed by, for example, blasting or lapping by projecting an abrasive onto the surface to be treated after the first step.

By selecting and adjusting the type of polishing, the amount of polishing (time), etc., the form of the texture (convex and concave portions) can be controlled. For example, when the polishing time (amount) per unit area is increased, the curvature of the convex portion generally increases (the radius of curvature decreases), and the concave portion may become shallower.

《Chrome plating layer》
The sliding surface is preferably made of a chrome plating layer. The chromium plating layer can improve the sliding characteristics (wear resistance, etc.) of the sliding surface. The above-mentioned texture is preferably formed on the chromium plating layer. However, the texture processing itself may be performed after or before chrome plating. The "chromium plating" referred to in this specification is preferably so-called hard chrome plating (also referred to as functional chrome plating or industrial chrome plating (JIS)).

The thickness of the chromium plating layer is preferably, for example, 3 to 20 μm, and more preferably 10 to 15 μm. The hardness of the chromium plating is preferably, for example, 850 to 1050 HV, and more preferably 900 to 1000 HV. The correlation between the hardness of the chrome plating layer and its wear resistance is not necessarily clear, but if the hardness is too low, no improvement in wear resistance can be expected, and if the hardness is too high, the amount of wear on the mating material (traveler) may increase. .

"others"
(1) Rings and travelers may be made of any material. The ring may be made of carbon steel or alloy steel, for example. The traveler may be made of, for example, spring steel or high carbon steel. The traveler can be prevented from adhering to the sliding partner (ring) by heat treatment (oxidation treatment).

(2) Thread (fiber)
The type of thread that comes into sliding contact with the traveler does not matter. If I had to say so, I would say that yarns that can naturally supply lubricating components under non-liquid lubrication (dry state) in the atmosphere, such as cotton, linen, silk, wool, and chemical fibers (nitrocellulose, nylon, vinylon, etc.), can be spun. Preferred as a target.

Rings and the like may be used not only for spinning thin yarns but also for spinning thick yarns. Even when a heavy traveler is used when spinning thick yarn, desired sliding characteristics can be ensured by combining it with the ring according to the present invention.

"overview"
A plurality of disks (samples) were fabricated with a texture formed after chrome plating on the surface to be treated of the substrate that would serve as the sliding surface. Using each disc and ball, the sliding characteristics (low friction sliding distance) under non-liquid lubrication (dry state) were evaluated by a ball-on-disc friction test (simply referred to as the "BOD test") (basic test). .

In addition, a ring having a textured sliding surface was attached to a ring spinning machine (simply referred to as the "actual machine"), and the influence of the texture on the sliding characteristics was evaluated using the actual machine (actual machine test). The present invention will be explained in more detail based on these specific examples.

[Basic exam]
《Sample production》
(1) Substrate A substrate made of bearing steel (JIS SUJ2) used for rings for spinning machines was prepared (φ30 mm x thickness 5 mm). The surface to be processed of the substrate was mirror-finished to have a surface roughness Ra of 0.08 μm.

(2) Chrome plating Chrome plating was applied to the surface to be treated. Chrome plating was performed by electroplating using a high speed bath. In each sample, the thickness of the chromium plating layer was approximately 13 μm. The film thickness was determined by measuring the wear marks after the sliding test using Calotest manufactured by CSM.

(3) Texture A texture was formed in the central area (a 10 mm square area surrounding the center) on the chrome plating layer as follows. First, using a nanosecond pulsed laser or a femtosecond pulsed laser, depressions (substantially hemispherical) with substantially circular openings were regularly (periodically) formed on the chromium plating layer (first step). The depressions were alternately arranged in a staggered manner. Although the size of the depression was changed for each sample, it was kept the same within the same sample. An example in which depressions of the same size are arranged in a staggered manner is shown in FIG. 2A. The morphology of the depressions formed in each sample (dent diameter: D, pitch (adjacent distance): P, depth: H) is summarized in Table 1. Note that the interval between the rows of the recesses arranged alternately was set at a half pitch (P/2 μm). For comparison, a sample without texture was also prepared.

Next, the surface to be treated in which the depressions were formed was polished (second step). The polishing process was performed using a mirror finishing device (AERO LAP manufactured by Yamashita Works Co., Ltd.). Specifically, as shown in FIG. 2B, an abrasive (MultiCone manufactured by the same company) was projected onto the surface to be treated. The abrasive material consists of abrasive grains (particle size: several mm) in which diamond particles (particle size: 2 to 4 μm) are attached to a core made of food material.

The abrasive material was supplied and projected at a conveyor speed of 120 mm/s (constant). The degree of polishing was adjusted by the relative movement speed of the nozzle with respect to the surface to be processed (referred to as "scanning speed"). Note that the abrasive material was projected from a direction of about 45° to the surface to be treated. At this time, the distance between the tip of the nozzle and the surface to be treated was approximately 50 mm.

FIG. 2C schematically shows how the form of the texture changes after laser processing (first step) and after polishing processing (second step). As a result of the polishing process, the flat surface formed between adjacent depressions became a curved convex portion, and the original depression became a concave portion with a rounded outer peripheral edge (surface side).

FIG. 3 illustrates how the shapes of convex portions and concave portions change depending on the scanning speed. The profile shown in FIG. 3 was obtained by measuring a longitudinal section of the surface of the substrate after polishing using a three-dimensional shape measuring machine (NewView 5022 manufactured by ZYGO). As is clear from Figure 3, as the scanning speed decreases, the contact time between the projected abrasive grains and the unit surface after laser processing becomes longer, so the texture becomes smoother with convex parts with small curvature radius and shallow concave parts. It becomes a continuous form.

For each sample, the radius of curvature of the convex portion obtained by measurement and observation as shown in FIG. 3 is also shown in Table 1. Note that, as described above, the radius of curvature was the radius of a circular arc that approximated the curve (curved surface) near the apex of each convex portion.

《Sliding test》
A ball-on-disk test (BOD test/basic test) in which a ball was slid on the disk of each sample was conducted using a tribometer manufactured by CSM. The state of this test is schematically shown in FIG. The ball (φ6 mm) used was made of bearing steel (JIS SUJ2), had a surface roughness of 0.08 μmRzjis, and a surface hardness of HV800 (test load: 100 g).

The sliding test was conducted under a test load of 4 N (Hertzian surface pressure (maximum value): 1036 MPa), a sliding speed of 0.2 m/s, and a sliding environment in the atmosphere without any lubricant (dry state). The sliding position between the ball and the disk was on a circle 4 mm (sliding radius) from the center of the disk. The coefficient of friction (μ) was calculated from the measured value (frictional force) obtained from a frictional resistance sensor attached to the ball side and the test load.

The sliding test was conducted as follows. First, the disk and ball of each sample are brought into direct contact with each other in a dry state and allowed to slide. After sliding for 5 m in this state, cellulose was supplied to the sliding part and sliding was further performed for 100 m (total sliding distance: 105 m).

Cellulose was supplied using a suspension in which cellulose powder (KC floc manufactured by Nippon Paper Industries Co., Ltd./average particle size 24 μm) was dispersed in a solvent (hydrofluoroether (C ₄ F ₉ OCH ₃ )/Novec 7100 manufactured by 3M Co., Ltd.). I dripped it. A suspension was prepared by blending cellulose powder: solvent = 122 mg: 25 mL and stirring with an ultrasonic cleaner. The dropping amount was 200 μL per test. The dropped suspension was spread on the disk and air-dried.

In this way, the change in friction coefficient with respect to the sliding distance was measured for each sample. An example of the measurement results (graph) is shown in FIG. 5A. For each sample, the distance when the coefficient of friction once decreased due to the dropping of cellulose and then returned to 0.6 (μ≦0.6 sliding distance) was determined from each graph. The results are summarized in Table 1 and FIG. 5B.

After the sliding test, the wear diameter on the sliding surface of the ball was measured. The wear diameter was measured when the sliding distance after dropping cellulose was 10 m (total sliding distance: 15 m) and when the sliding distance after dropping cellulose was 100 m (total sliding distance: 105 m). did. For some samples, the wear diameter of the ball was converted into the wear depth (reduction in diameter) of the ball, which is shown in FIG.

Further, FIG. 7 shows an SEM image (sample 6) of the sliding surface of the disk after the sliding distance reached 10 m (total sliding distance: 15 m).

"evaluation"
(1) As is clear from Table 1 and FIGS. 5A and 5B, the radius of curvature (R) of the convex portion of the texture formed on the sliding surface and the sliding distance until μ≦0.6 There was a correlation between them. That is, it has been found that when the radius of curvature (R) is within a predetermined range, the sliding distance increases significantly.

(2) As is clear from FIG. 6, it has been found that when the radius of curvature (R) is within a predetermined range, the amount of wear on the sliding ball is also reduced. Therefore, it was found that the sliding characteristics were significantly improved by providing the sliding surface with a texture having convex portions with a radius of curvature (R) within a predetermined range. As can be seen from FIG. 5A, FIG. 7, etc., it is presumed that the fibers (cellulose in this example) captured by the textured sliding surface are involved in the sliding characteristics.

[Actual machine test]
(1) Conditions A ring having the texture shown in Table 2 on its sliding surface and a traveler are assembled into an actual machine (ring spinning machine RX240 manufactured by Toyota Industries Corporation), and the sliding distance until the traveler reaches the end of its life is calculated. I asked for it. The results are summarized in Table 2. At this time, the actual machine was operated at a maximum rotational speed of 21,000 rpm in a dry environment. The life of the traveler was defined as the time when the initial thickness (t) of the traveler became 1/2 (0.5t), and was expressed by the sliding distance up to that time.

Disks with similar textures were prepared and subjected to the BOD test in the same manner as the basic test. The test load at this time was 2N (Hertzian surface pressure (maximum value): 822 MPa). In this way, the sliding distance until the friction coefficient returned to 0.8 to 0.9 was determined for each sample. The results are also shown in Table 2. Note that the sliding radius (sliding position between the disk and the ball) was 4 mm and 8 mm. When the sliding radius was 8 mm, the area where the disk was formed was a 20 mm square area surrounding the center.

Incidentally, the above BOD test was conducted by dropping 100 mg of cellulose powder onto the center of the rotating disk immediately after sliding it for 5 meters in a dry state. The cellulose particles collide with the ball (steel ball) while scattering in the outer circumferential direction. The cellulose particles compressed by the disk and ball lubricate the sliding movement of the disk and ball. Due to the difference in scattering speed, more cellulose particles are supplied to the region with a large sliding radius (8 mm) than to the region with a small sliding radius (4 mm). Therefore, the lubricity due to the cellulose particles is higher in the latter region than in the former region.

(2) Results The results of the BOD test shown in Table 2 and the actual machine test are summarized in FIG. 8. As is clear from FIG. 8, it was confirmed that when similar textures were formed on the sliding surfaces, there was a correlation between the results of both tests. In other words, it was confirmed that the BOD test can be used as a substitute for the actual machine test.

[Supplementary exam]
A BOD test (test load: 4N) was conducted with an extended sliding distance. The results are shown in FIG. 9A. The sliding surface of the disk used at this time was also textured by polishing the depressions (D: 40 μm, P: 70 μm, H: 4 μm) formed by laser processing (the radius of curvature of the convex portion). R: 86 μm).

A SEM image of the sliding surface after the test is shown in FIG. 9B. Further, the wear diameter on the sliding surface of the ball after the test was 347 μm (5 μm when converted to wear depth). By the way, when using a disk without texture, the wear diameter of the ball is 412 μm (wear depth: 7.1 μm) when the sliding distance is 100 m, and the wear diameter of the ball is 463 μm (wear depth: 7.1 μm) when the sliding distance is 200 m. Wear depth: 8.9 μm).

From these facts, if a texture with convex portions with a radius of curvature within a predetermined range is formed on the sliding surface, the lubricating effect of the fibers will be stably exerted, and the sliding distance with low friction will be extended. It was revealed that the wear of the mating material was also suppressed.

11 Ring 12 Traveler 13 Chrome plating layer

Claims (6)

A ring used in a spinning machine that winds yarn through a traveler and having a sliding surface on which the traveler slides,
The sliding surface has a texture including a plurality of recesses and a curved protrusion between adjacent recesses,
The convex portion is a ring for a spinning machine and has a radius of curvature of 40 to 400 μm. The ring for a spinning machine according to claim 1, wherein the interval between adjacent recesses is 40 to 100 μm. The ring for a spinning machine according to claim 1 or 2, wherein the sliding surface comprises a chrome plating layer. A method for manufacturing a ring for a spinning machine according to any one of claims 1 to 3, comprising:
The sliding surface includes a first step of forming a plurality of depressions on the treated surface of the ring;
A method for producing a spinning frame ring obtained through a second step of rounding the periphery of the depression and/or the adjacent areas of the depression. 5. The method for manufacturing a ring for a spinning machine according to claim 4, wherein the first step is performed by irradiating the surface to be treated with a laser. 6. The method for manufacturing a ring for a spinning frame according to claim 4, wherein the second step is performed by projecting an abrasive onto the surface to be treated after the first step.

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