Hollow guide shaft body, air spinning device, and yarn winder assembled with the same

Abstract

To provide a hollow guide shaft body with suppressed peeling of a surface layer.SOLUTION: A hollow guide shaft body 32 is provided with a fiber passage where, in an air spinning device, a fiber affected by a rotation air current rotates around and a fiber twisted by the rotation air current passes. This hollow guide shaft body 32 is assembled with a base material part 50 having electric conductivity, an intermediate layer 51 that is a layer harder than the base material part 50 and formed on a surface of the base material part 50, and a surface layer 52 that is a layer harder than the intermediate layer 51 and formed on at least a part of a surface of the intermediate layer 51. A hardness of the intermediate layer 51 is 1000Hv or over and 1500Hv or under and a thickness of the intermediate layer 51 is 60 μm or over and 200 μm or under.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a configuration of a hollow guide shaft provided in a pneumatic spinning device. [Background technology]

[0002] 2. Description of the Related Art Air spinning devices are known that apply a swirling air current to a fiber bundle to twist the fiber bundle and produce a spun yarn.

[0003] An air spinning device includes a spindle (hollow guide shaft). The spindle has a cylindrical or conical shape, and a predetermined space (swirl chamber) is formed around the spindle. In the air spinning device, fibers are subjected to the action of a swirling air flow and are swung around the spindle in the swirl chamber. This adds twist to the fibers, producing spun yarn.

[0004] Patent Document 1 discloses a hollow guide shaft having a substrate formed of a conductive material such as stainless steel, on which an intermediate layer and a surface layer are provided. The surface layer is a coating made of diamond-like carbon or the like that is harder than the substrate. The intermediate layer also serves to bond the substrate and the surface layer together. The hollow guide shaft disclosed in Patent Document 1 has higher wear resistance and toughness than conventionally used ceramic spindles, and is less likely to generate static electricity between the shaft and the fibers. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-005562 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the hollow guide shaft disclosed in Patent Document 1 has a problem in that the surface layer is easily peeled off due to an impact load.

[0007] The present invention has been made in view of the above circumstances, and a main object of the present invention is to provide a hollow guide shaft body that can suppress peeling of the surface layer. [Means for solving the problem]

[0008] Below, several aspects will be described as means for solving the problems. These aspects can be combined as needed.

[0009] According to an aspect of the present invention, there is provided the following configuration of a hollow guide shaft in an air spinning device, in which fibers subjected to the action of a swirling air current swirl around and a fiber passage is formed through which fibers twisted by the swirling air current pass. The hollow guide shaft includes a substrate, an intermediate layer that is harder than the substrate and formed on the surface of the substrate, and a surface layer that is harder than the intermediate layer and formed on at least a portion of the surface of the intermediate layer. The hardness of the intermediate layer is 1000 Hv or more and 1500 Hv or less, and the thickness of the intermediate layer is 60 μm or more and 200 μm or less.

[0010] This hollow guide shaft has a relatively thick intermediate layer between the surface layer and the base material. The intermediate layer not only functions to bring the base material and the surface layer into close contact with each other, but also absorbs the difference in the amount of elastic deformation between the base material and the surface layer in response to an impact load applied to the surface layer. As a result, even when an impact load acts on the surface layer, the surface layer is prevented from peeling off from the intermediate layer. Therefore, this hollow guide shaft can prevent peeling of the surface layer.

[0011] In the hollow guide shaft, the hardness of the surface layer may be 2000 Hv or more and 3500 Hv or less.

[0012] This makes the surface layer harder than ceramic, achieving high wear resistance.

[0013] In the hollow guide shaft, the surface layer may have a thickness of 3 μm or more and 7 μm or less.

[0014] This allows the surface layer to both ensure its lifespan and prevent peeling. More specifically, by making the surface layer 3 μm or thicker, a sufficient period (lifespan) is ensured before wear occurs, even if the surface layer is worn. Furthermore, by making the surface layer 7 μm or thicker, a decrease in the toughness of the surface layer is prevented.

[0015] In the hollow guide shaft, the intermediate layer has a lower hardness on the substrate side than on the surface layer side.

[0016] This prevents the difference in hardness between the surface of the intermediate layer facing the substrate and the hardness of the substrate from increasing, and also prevents the difference in hardness between the surface of the intermediate layer facing the surface layer and the hardness of the surface layer from increasing. As a result, the intermediate layer and the substrate can effectively absorb impact loads acting on the surface layer, thereby preventing peeling of the surface layer.

[0017] In the above hollow guide shaft, the surface layer may be a diamond-like carbon coating.

[0018] This allows the formation of a surface layer with sufficient hardness. Furthermore, because the diamond-like carbon coating has a low coefficient of friction, it is possible to reduce friction between the hollow guide shaft and the fibers. This further increases the rotation speed of the fibers, thereby further increasing the spinning speed of the air spinning device.

[0019] In the above hollow guide shaft, the surface layer may include at least one of convex portions formed by attached droplets and concave portions formed by fallen droplets, and the maximum peak height Rp may be greater than 0 μm and not more than 2.0 μm, and the arithmetic mean height Ra may be not more than 0.4 μm.

[0020] This makes it possible to prevent the unevenness formed by droplets that occurs when a diamond-like carbon coating is formed using the arc ion plating method from increasing the coefficient of friction between the fiber and the surface layer.

[0021] In the above hollow guide shaft, the diameter of the convex portion or the diameter of the concave portion of the surface layer may be 1 μm or more and 10 μm or less when viewed from the normal direction.

[0022] This makes it possible to prevent the unevenness formed by droplets that occurs when a diamond-like carbon coating is formed using the arc ion plating method from increasing the coefficient of friction between the fiber and the surface layer.

[0023] In the above hollow guide shaft, the surface layer has a number of convex or concave portions of 10,000 μm 2 The number of pieces may be 3 or more and 30 or less.

[0024] This makes it possible to prevent the unevenness formed by droplets that occurs when a diamond-like carbon coating is formed using the arc ion plating method from increasing the coefficient of friction between the fiber and the surface layer.

[0025] In the above hollow guide shaft, the surface layer may have a width of 5 mm or more extending from the edge surrounding the entrance of the fiber passage along the surface of the hollow guide shaft in a direction away from the entrance of the fiber passage.

[0026] This allows the surface layer to cover the area where the fibers come into contact with the hollow guide shaft (fiber contact area), thereby preventing the intermediate layer and / or substrate of the hollow guide shaft from being worn down due to contact with the fibers.

[0027] In the above hollow guide shaft, the surface layer may have a width of 2 mm or less at a portion extending from an edge surrounding the entrance of the fiber passage along the inner wall surface of the fiber passage in a direction away from the entrance of the fiber passage.

[0028] The outer surface of the hollow guide shaft (the area excluding the inner wall surface surrounding the fiber passage) may be subjected to impact loads due to collision with another component during maintenance of the air spinning device, etc. By limiting the area covered by the surface layer of the fiber passage, which is less likely to be subjected to impact loads, the process of forming the surface layer is simplified, and the manufacturing costs of the hollow guide shaft are reduced.

[0029] In the hollow guide shaft, the substrate may be made of at least one of iron, conductive ceramics, cemented carbide, and stainless steel.

[0030] The air spinning device includes the hollow guide shaft, a swirl chamber forming member in which a swirl chamber in which the fibers swirl is formed, and a fiber guide portion that guides the fibers into the swirl chamber.

[0031] According to another aspect of the present invention, there is provided an air spinning device including the above-mentioned hollow guide shaft, a swirl chamber forming member in which a swirl chamber in which fibers swirl is formed, and a fiber guide section that guides the fibers into the swirl chamber.

[0032] The hollow guide shaft is easy to handle because peeling of the surface layer is suppressed, and therefore an air spinning device including the hollow guide shaft is also easy to handle.

[0033] According to yet another aspect of the present invention, there is provided a yarn winding machine including the air spinning device described above and a winding section that winds the spun yarn produced by the air spinning device to form a package.

[0034] This yarn winding machine employs the air spinning device and is therefore easy to handle.

[0035] According to yet another aspect of the present invention, there is provided the following configuration of a hollow guide shaft in an air spinning device, in which fibers subjected to the action of a swirling air current swirl around and fibers twisted by the swirling air current pass through. The hollow guide shaft includes a base material, an intermediate layer that is harder than the base material and formed on the surface of the base material, and a surface layer that is harder than the intermediate layer and formed on the surface of the intermediate layer. The surface layer has a width of 5 mm or more and 20 mm or less extending from an edge surrounding the fiber passage entrance along the surface of the hollow guide shaft in a direction away from the fiber passage entrance. The intermediate layer has a wider width from the edge surrounding the fiber passage entrance than the surface layer.

[0036] This allows the area where the fibers come into contact with the hollow guide shaft (fiber contact area) to be covered with the surface layer. This prevents the intermediate layer and / or base material of the hollow guide shaft from being worn down due to contact with the fibers. Furthermore, not covering the entire intermediate layer and base material with the surface layer simplifies surface treatment, thereby preventing an increase in the manufacturing cost of the hollow guide shaft. [Effects of the Invention]

[0037] This hollow guide shaft body can suppress peeling of the surface layer. [Brief explanation of the drawings]

[0038] [Figure 1] 1 is a front view showing the overall configuration of a yarn winding machine according to an embodiment of the present invention. [Figure 2] FIG. [Figure 3] FIG. 2 is a vertical cross-sectional view of the air spinning device. [Figure 4] FIG. 10 is a vertical cross-sectional view of the air spinning device showing how twisting is being applied to a fiber bundle. [Figure 5] FIG. 2 is a longitudinal cross-sectional view showing a fiber contact portion. [Figure 6] FIG. 2 is a diagram conceptually showing the structure of the surface of a hollow guide shaft body. [Figure 7] FIG. 6 is an enlarged view of part A in FIG. 5. [Figure 8]FIG. 1 is a cross-sectional view conceptually illustrating a droplet. [Figure 9] 10 is a graph showing the evaluation results of the first example. [Figure 10] 10 is a graph showing the evaluation results of the second example. DETAILED DESCRIPTION OF THE INVENTION

[0039] 1. First embodiment (1) Hollow guide shaft, air spinning device, and yarn winding machine equipped with the same A hollow guide shaft 32, an air spinning device 5, and a yarn winding machine 1 including the same according to a first embodiment of the present invention will now be described. As shown in Fig. 1, the yarn winding machine 1 mainly includes a number of spinning units 2 arranged in parallel and a yarn splicing cart 3. As shown in Fig. 2, each spinning unit 2 includes, in order from upstream to downstream, a draft device 4, an air spinning device 5, a yarn monitoring device 6, a yarn storage device 7, and a winding section 8. In this specification, "upstream" and "downstream" refer to upstream and downstream in the running direction of the fiber bundle and spun yarn during spinning.

[0040] The draft device 4 drafts sliver (raw material for the fiber bundle) 9 to form a fiber bundle 10. The draft device 4 has multiple draft rollers 11, 12, 13, and 14, and opposing rollers arranged to face each draft roller. The multiple draft rollers 11, 12, 13, and 14 are each driven to rotate at a predetermined rotational speed. The draft device 4 drafts the sliver 9 supplied from a sliver case (not shown) by sandwiching it between the rotating draft rollers 11, 12, 13, and 14 and the opposing rollers facing them, and transporting the sliver 9 to form a fiber bundle 10. The fiber bundle 10 drafted by the draft device 4 is supplied to the air spinning device 5.

[0041] The air spinning device 5 generates a swirling air current therein, and causes the swirling air current to act on the fiber bundle 10, thereby twisting the fiber bundle 10 and producing a spun yarn 15. The detailed configuration of the air spinning device 5 will be described later.

[0042] The spun yarn 15 produced by the air spinning device 5 passes through the yarn monitoring device 6. The yarn monitoring device 6 monitors the condition of the traveling spun yarn 15 and detects any abnormalities in the quality of the spun yarn 15 (yarn defects). The yarn monitoring device 6 may be provided with a cutter 16 for cutting the spun yarn 15 when a yarn defect is detected.

[0043] The spun yarn 15 that has passed through the yarn monitoring device 6 is wound onto a bobbin 17 by the winding section 8. The winding section 8 includes a cradle arm 19, a winding drum 20, and a traverse device 21.

[0044] The cradle arm 19 rotatably supports the bobbin 17 for winding the spun yarn 15. The winding drum 20 comes into contact with the outer peripheral surface of the bobbin 17 and is driven to rotate, thereby rotating the bobbin 17. The traverse device 21 is equipped with a traverse guide 22 that engages with the spun yarn 15 and is driven left and right (in the winding width direction of the bobbin 17). The traverse device 21 traverses the spun yarn 15 being wound onto the bobbin 17.

[0045] The spinning unit 2 configured as described above can produce the spun yarn 15 from the sliver 9 and wind it onto the bobbin 17. The bobbin 17 with the spun yarn 15 wound thereon is called a "package."

[0046] Furthermore, in the yarn winding machine 1 of the present embodiment, a yarn pooling device 7 is disposed between the yarn monitoring device 6 and the winding section 8. As shown in FIG. 2, the yarn pooling device 7 includes a yarn pooling roller 23 and an electric motor 25 that drives and rotates the yarn pooling roller 23.

[0047] The yarn pooling roller 23 can temporarily store a certain amount of spun yarn 15 by winding it around its outer circumferential surface. By temporarily storing the spun yarn 15 in this way, the yarn pooling device 7 functions as a kind of buffer. This can eliminate problems (such as slack in the spun yarn 15) that may occur when the spinning speed in the air spinning device 5 and the winding speed in the winding section 8 do not match for some reason.

[0048] Each spinning unit 2 is also provided with a unit control section 26. The unit control section 26 controls each component included in the spinning unit 2 as appropriate.

[0049] As shown in Figures 1 and 2, the yarn splicing cart 3 is equipped with a yarn splicing device 27 and a suction device (suction pipe 28 and suction mouth 29). The yarn splicing cart 3 is capable of traveling in the direction in which the spinning units 2 are lined up (left and right direction in Figure 1). If the spun yarn 15 between the air spinning device 5 and the winding section 8 in a certain spinning unit 2 becomes cut for some reason, the yarn splicing cart 3 travels to the front of that spinning unit 2 and splices the cut spun yarn 15.

[0050] The yarn joining device 27 joins the yarn ends together. The configuration of the yarn joining device 27 is not particularly limited, but for example, an air splicer that twists the yarn ends together using a swirling air current can be used. The suction pipe 28 sucks in and captures the yarn end delivered from the air spinning device 5, and guides it to the yarn joining device 27. The suction mouth 29 sucks in and captures the yarn end from the package 18 supported by the winding unit 8, and guides it to the yarn joining device 27.

[0051] Next, the configuration of the air spinning device 5 will be described in detail with reference to Fig. 3. Fig. 3 is a schematic vertical cross-sectional view of the air spinning device 5 taken along a plane passing through the axis of the hollow guide shaft body 32.

[0052] 3, the air spinning device 5 includes a fiber guide block 30, a nozzle block 31, a hollow guide shaft body 32, and a casing 33. The casing 33 is made up of an upstream casing 33a and a downstream casing 33b.

[0053] The fiber guide block 30 is formed with a fiber introduction hole 34 for introducing the fiber bundle 10 drafted by the draft device 4. The fiber guide block 30 also holds a needle (fiber guide portion) 44 arranged on the path of the fiber bundle 10. The fiber guide block 30 is also held in an upstream casing 33a. The fiber guide block 30 does not necessarily have to have the needle 44.

[0054] As shown in Figure 3, the hollow guide shaft 32 has a tapered section 37 whose shape expands toward the downstream side, and a cylindrical section 38. The cylindrical section 38 is connected to the larger diameter side of the tapered section 37 so that their axes are aligned. A fiber passage 39 is formed in the axial center of the cylindrical section 38 and the tapered section 37. This makes the hollow guide shaft 32 hollow.

[0055] The tapered portion 37 of the hollow guide shaft 32 is arranged so that the small diameter side faces the upstream side. The cylindrical portion 38 of the hollow guide shaft 32 is held in the downstream casing 33b.

[0056] An inlet 40a of a fiber passage 39 opens at the upstream end of the hollow guide shaft 32 (the end on the small-diameter side of the tapered portion 37). The upstream end face of the hollow guide shaft 32 is called the inlet portion 40 of the fiber passage 39. As shown in FIG. 3, the inlet portion 40 has an opening formed in the center, which is the inlet of the fiber passage 39, and is positioned so as to face the tip of the needle 44. With the above configuration, the fiber bundle 10 introduced into the fiber introduction hole 34 is guided by the needle 44 and introduced into the fiber passage 39 from the opening formed in the inlet portion 40 (see FIG. 4). The downstream end of the fiber passage 39 is an outlet hole (not shown).

[0057] The nozzle block 31 is formed with a swirl chamber 41 and a tapered chamber 42. Therefore, the nozzle block 31 can also be called a swirl chamber-forming member. The swirl chamber 41 is formed as a substantially cylindrical space and is connected to the fiber introduction hole 34. The tapered chamber 42 is formed as a tapered space that widens toward the downstream side. The tapered chamber 42 is located downstream of the swirl chamber 41 and is connected to the swirl chamber 41. The nozzle block 31 is held in the upstream casing 33a.

[0058] The casing 33 is configured to be openable and closable. When the casing 33 is closed (the upstream casing 33a and the downstream casing 33b are close to each other, as shown in FIG. 3), the tapered portion 37 of the hollow guide shaft 32 is arranged so that it is partially inserted into the swirl chamber 41 and the tapered chamber 42. The hollow guide shaft 32 is arranged so that its axis coincides with that of the swirl chamber 41 and the tapered chamber 42. Furthermore, when the casing 33 is closed, a predetermined space (the swirl chamber 41 and the tapered chamber 42) is formed between the outer peripheral surface of the hollow guide shaft 32 and the inner surface of the nozzle block 31. When the air spinning device 5 produces spun yarn 15, the casing 33 is in this closed state.

[0059] By opening the casing 33 (a state in which the upstream casing 33a and the downstream casing 33b are separated, not shown), the hollow guide shaft 32 can be separated from the nozzle block 31 and the fiber guide block 30. This allows the hollow guide shaft 32 to be exposed to the outside. For example, if debris such as fiber waste has accumulated on the hollow guide shaft 32, the casing 33 can be opened as described above to expose the hollow guide shaft 32, allowing cleaning of the hollow guide shaft 32. The nozzle block 31 and the fiber guide block 30 may be integrally configured.

[0060] An air supply chamber 35 is formed around the nozzle block 31. A compressed air supply pipe 36 connected to a compressed air source (not shown) is connected to the upstream casing 33a. This allows compressed air to be supplied from the compressed air source to the air supply chamber 35.

[0061] The nozzle block 31 is formed with one or more air ejection nozzles 43 that communicate between the swirl chamber 41 and the air supply chamber 35. The air ejection nozzles 43 are formed so that their longitudinal direction is oriented in a direction approximately tangential to the swirl chamber 41 in a plan view. The compressed air supplied to the air supply chamber 35 is ejected into the swirl chamber 41 through the air ejection nozzles 43. This generates a swirling airflow in the swirl chamber 41 that flows in one direction around the axis of the hollow guide shaft 32.

[0062] 3, the air ejection nozzle 43 is formed so that its longitudinal direction is slightly inclined toward the downstream side, thereby allowing the compressed air ejected from the air ejection nozzle 43 to flow toward the downstream side.

[0063] With the above configuration, the compressed air injected from the air ejection nozzle 43 flows downstream while swirling around the hollow guide shaft 32 in the swirling chamber 41. In this way, a spiral swirling air current flowing downstream can be generated in the swirling chamber 41.

[0064] Next, how the air spinning device 5 of this embodiment twists the fiber bundle 10 to produce the spun yarn 15 will be described with reference to Fig. 4. In Fig. 4, the air flow within the air spinning device 5 is indicated by thick arrows.

[0065] The fiber bundle 10 is made up of a large number of fibers. The downstream end of each fiber constituting the fiber bundle 10 is twisted into the fiber bundle 10 while being twisted, while the upstream end is a free end. The free end of each fiber introduced into the air spinning device 5 through the fiber introduction hole 34 is carried downstream by the air flow generated by the air ejected from the air ejection nozzle 43. As the upstream end (free end) of the fiber is carried downstream in this manner, the orientation of the upstream end is "inverted" and faces downstream (the lower side in Figure 4). The fiber in this state is called a reversed fiber 10b.

[0066] Some of the fibers contained in the fiber bundle 10 are in a continuous state between the fiber introduction hole 34 and the fiber passage 39. The fibers in this state are called core fibers 10a.

[0067] The free ends of the reverse fibers 10b are affected by the swirling airflow that flows spirally around the hollow guide shaft 32 in the swirling chamber 41. As a result, the reverse fibers 10b move along the surface of the tapered portion 37 of the hollow guide shaft 32 and swirl around the tapered portion 37, as shown in Fig. 4. As a result, the reverse fibers 10b are sequentially wound around the core fibers 10a.

[0068] The core fiber 10a is twisted by the rotating reverse fiber 10b. In this way, the reverse fiber 10b is wound around the core fiber 10a, and further twisting is applied to the core fiber 10a, so that the reverse fiber 10b is twisted into the core fiber 10a, and a spun yarn 15 is produced.

[0069] The twist of the core fibers 10a tends to propagate upstream (toward the front roller 14), but this propagation is prevented by the needles 44. In this way, the needles 44 function as twist propagation prevention means.

[0070] The spun yarn 15 produced by the air spinning device 5 is wound by the winding section 8, and a downstream transport force is applied to the spun yarn 15. As a result, the spun yarn 15 and the core fiber 10a are transported downstream as a whole. The reverse fiber 10b wound around the core fiber 10a is dragged by the core fiber 10a transported downstream and into the fiber passage 39 through the opening of the fiber passage 39.

[0071] As explained above, the reversible fibers 10b are swung around the tapered portion 37 of the hollow guide shaft 32, and friction occurs between the outer peripheral surface of the tapered portion 37 and the reversible fibers 10b. However, friction does not occur over the entire outer peripheral surface of the tapered portion 37, but occurs mainly in a portion of the outer peripheral surface of the tapered portion 37 close to the inlet portion 40 (portion indicated by 37a in FIG. 5), the inlet portion 40, and an edge 39a of the inlet portion 40 surrounding the inlet 40a. Hereinafter, for convenience, the portion 37a of the surface of the hollow guide shaft 32 where friction occurs, particularly with the fibers, the inlet portion 40, and the edge 39a will be collectively referred to as the "fiber contact portion" (portion indicated by the thick line in FIG. 5).

[0072] (2) Surface structure of hollow guide shaft The hollow guide shaft 32 comprises a base material portion 50, an intermediate layer 51, and a surface layer 52. More specifically, the intermediate layer 51 and the surface layer 52 are formed on the surface of the base material portion 50, which is formed so as to have a tapered portion 37 and a cylindrical portion 38. Fig. 6 is a diagram conceptually showing the structure of the surface of the hollow guide shaft.

[0073] The base material 50 is made of stainless steel (e.g., SUS304) and is electrically conductive. The downstream casing 33b that holds the hollow guide shaft 32 is made of a material (specifically, metal) that has good electrical conductivity so that static electricity generated in the hollow guide shaft 32 can be released. Furthermore, the downstream casing 33b is electrically connected to a metal frame that constitutes the spinning unit 2. The metal frame is grounded.

[0074] The above configuration suppresses static electricity from building up on the hollow guide shaft 32. This suppresses the adhesion of debris such as fiber waste to the surface of the hollow guide shaft 32, and the surface of the hollow guide shaft 32 can be kept constantly clean, improving the quality of the spun yarn 15 produced by the air spinning device 5. Furthermore, the productivity of the spinning unit 2 is improved because the maintenance work required to clean the surface of the hollow guide shaft 32 can be reduced.

[0075] The intermediate layer 51 is a layer formed by surface treatment performed on the surface of the base material 50. The intermediate layer 51 is a layer harder than the base material 50. The intermediate layer 51 is formed to adhere the surface layer 52, which has a significantly different hardness from the base material 50, to the base material 50. The intermediate layer 51 has a heat-treated layer 53, a nitriding layer 54, and a plating layer 55.

[0076] The heat-treated layer 53 is a layer that has been subjected to heat treatment such as quenching and tempering to improve the hardness of the surface of the base material 50. The heat-treated layer 53 is the first layer to be formed.

[0077] The nitrided layer 54 is a layer obtained by performing a known nitriding process on the heat-treated layer 53. This further improves the hardness of the surface of the substrate 50. If a compound layer is formed on the surface of the substrate 50 by the nitriding process, there is a concern that the compound layer may peel off from the surface of the substrate 50. Therefore, it is preferable to use a nitriding method (e.g., radical nitriding) that forms only a diffusion layer without forming a compound layer.

[0078] The plated layer 55 is a layer in which a hard plated coating of tungsten, chromium, etc. is formed on the nitrided layer 54. The plated layer 55 may be omitted.

[0079] The hardness of the intermediate layer 51 is preferably 1000 Hv or more and 1500 Hv or less.

[0080] The intermediate layer 51 may have a hardness gradient such that the hardness on the substrate 50 side is lower than the hardness on the surface layer 52 side. Specifically, the intermediate layer 51 may have a hardness gradient such that the hardness on the substrate 50 side is 1000 Hv or more and 1200 Hv or less, and the hardness on the surface layer 52 side is 1300 Hv or more and 1500 Hv or less. For example, the intermediate layer 51 has a hardness gradient of 1000 Hv in 70 μm on the substrate 50 side and 1200 Hv in 30 μm on the surface layer 52 side. Examples of the hardness gradient of the intermediate layer 51 include a linear gradient or a step-like gradient in an approximation curve.

[0081] The thickness of the intermediate layer 51 is preferably 60 μm or more and 200 μm or less.

[0082] The height and thickness of the intermediate layer 51 are controlled by the treatment time, treatment temperature, etc. of the heat treatment and / or nitriding treatment.

[0083] The intermediate layer 51 is electrically conductive, and therefore, the intermediate layer 51 can release static electricity generated in the hollow guide shaft body 32.

[0084] The surface layer 52 is a coating layer formed on at least a portion of the surface of the intermediate layer 51. The surface layer 52 is a layer harder than the intermediate layer 51. In this embodiment, the surface layer 52 is a diamond-like carbon coating (hereinafter also referred to as a DLC coating). As is well known, a DLC coating is much harder than stainless steel. Therefore, by forming the surface layer 52 (DLC coating) on ​​the surface of the substrate portion 50, the wear resistance of the hollow guide shaft body 32 is significantly improved. The surface layer 52 is formed, for example, by an arc ion plating method.

[0085] From the viewpoint of improving the wear resistance of the hollow guide shaft body 32, it is preferable that a surface layer 52 is formed at least on the portion that comes into contact with the fibers (the fiber contact portion shown in FIG. 5). Specifically, it is preferable that the width w1 (the range indicated by the dotted line in FIG. 5) of the portion of the surface layer 52 that extends from the edge 39a along the surface of the hollow guide shaft body 32 in a direction away from the inlet 40a is 5 mm or more.

[0086] The surface layer 52 preferably has a width w2 (see FIG. 7) of 2 mm or less at a portion extending from the edge 39a along the inner wall surface of the fiber passage 39 in a direction away from the inlet 40a (toward the cylindrical portion 38).

[0087] The hardness of the surface layer 52 is preferably 2000 Hv or more and 3500 Hv or less.

[0088] The thickness of the surface layer 52 is preferably 3 μm or more and 7 μm or less.

[0089] When the surface layer 52 is formed using an arc ion plating method, molten carbon particles, called droplets, having a size ranging from submicrons to several microns, may adhere to or be embedded in the surface of the surface layer 52. As shown in FIG. 8, the surface of the surface layer 52 is formed with fine irregularities, such as protrusions 62a formed by the attached droplets 61 and recesses 62b formed by the fallen droplets 61. As shown in FIG. 8, the protrusions 62a may be formed by the droplets 61 themselves that adhere to the surface layer 52 (protrusions 62aa), or by droplets 61 at least partially embedded in the surface layer 52 (protrusions 62ab). In FIG. 8, the imaginary lines of the droplets 61 that have fallen and formed recesses 62b are indicated by dashed lines.

[0090] The protrusions 62a and recesses 62b are preferably small from the viewpoint of suppressing friction occurring between the fibers and the surface layer 52. Specifically, when the protrusions 62a and recesses 62b are formed, the surface roughness of the surface layer 52 is preferably such that the maximum peak height Rp is greater than 0 μm and not more than 2.0 μm, and the arithmetic mean height Ra is not more than 0.4 μm, according to the JIS standard (JIS B0601:2013).

[0091] Furthermore, the diameter d1 of the convex portion 62a or the diameter d2 of the concave portion 62 is preferably 1 μm or more and 10 μm or less when viewed from the normal direction ND of the surface layer 52.

[0092] Furthermore, the number of the convex portions 62a or the concave portions 62b is 10000 μm 2 It is preferable that there are 3 or more and 30 or less per unit area.

[0093] The surface roughness of the surface layer 52 caused by the droplets 61, and the size and number of the convex portions 62a and concave portions 62b are controlled by the deposition time of the surface layer 52, the use of a filter, processing using shot blasting after deposition, etc.

[0094] It is preferable that the surface layer 52 also has electrical conductivity so that static electricity generated in the hollow guide shaft body 32 can be released to the base material portion 50 .

[0095] (3) Variations The material of the substrate 50 does not need to be electrically conductive. However, from the viewpoint of adhesion of the DLC coating, it is preferable that the material of the substrate 50 be electrically conductive. In this case, the material of the substrate 50 is not limited to stainless steel, and any material having good electrical conductivity may be used. In addition to stainless steel, examples of such materials include iron, conductive ceramics, and cemented carbide such as tungsten carbide. However, in terms of corrosion resistance and appropriate toughness, it is preferable to use stainless steel for the substrate 50 as in the above embodiment.

[0096] The surface layer 52 is not limited to a DLC coating, but may be a coating of chromium nitride (CrN), titanium nitride (TiN), titanium carbide (TiC), vanadium carbide (VC), or the like.

[0097] The surface layer 52 may be formed on the entire inner wall surface surrounding the fiber passage 39, or may not be formed on the entire inner wall surface surrounding the fiber passage 39.

[0098] The spinning unit 2 may further include a suction and catching device (not shown). The suction and catching device is provided between the yarn pooling device 7 and the winding section 8. The suction and catching device suctions and catches the spun yarn 15 traveling between the yarn pooling device 7 and the winding section 8. Specifically, if the spun yarn 15 is cut, the suction and catching device suctions and catches the spun yarn 15 on the package side. Even more specifically, by rotating the yarn pooling roller 23 while stopping the rotation of the package, the suction and catching device suctions and catches the spun yarn 15 unwound from the yarn pooling roller 23. When the yarn splicing cart 3 performs work on the spinning unit 2, the suction and catching device is located upstream of the yarn splicing device 27 of the yarn splicing cart 3.

[0099] (4) Features of the First Embodiment As described above, the hollow guide shaft 32 is formed with a fiber passage 39 through which fibers subjected to the action of the swirling air current in the air spinning device 5 swirl and through which fibers twisted by the swirling air current pass. The hollow guide shaft 32 includes an electrically conductive substrate 50, an intermediate layer 51 that is harder than the substrate 50 and formed on the surface of the substrate 50, and a surface layer 52 that is harder than the intermediate layer 51 and formed on at least a portion of the surface of the intermediate layer 51. The hardness of the intermediate layer 51 is 1000 Hv or more and 1500 Hv or less, and the thickness of the intermediate layer 51 is 60 μm or more and 200 μm or less.

[0100] In components in which a high-hardness coating such as a DLC coating is formed on the surface of a substrate made of a highly ductile material such as stainless steel, when an impact load is applied, the coating can deform in response to the elastic deformation of the substrate, which can cause the coating to peel off.

[0101] In the hollow guide shaft 32, the intermediate layer 51 provided between the surface layer 52 and the base material 50 is formed to be relatively thick. The intermediate layer 51 formed in this manner not only functions to bring the base material 50 and the surface layer 52 into close contact with each other, but also absorbs the difference in the amount of elastic deformation between the base material 50 and the surface layer 52 in response to an impact load applied to the surface layer 52. As a result, even when an impact load acts on the surface layer 52, peeling of the surface layer 52 from the intermediate layer 51 is suppressed. Therefore, the hollow guide shaft 32 can suppress peeling of the surface layer 52.

[0102] In the hollow guide shaft body 32, the hardness of the surface layer 52 may be 2000 Hv or more and 3500 Hv or less.

[0103] This makes the surface layer 52 harder than ceramic, and provides high wear resistance.

[0104] In the hollow guide shaft body 32, the thickness of the surface layer 52 may be 3 μm or more and 7 μm or less.

[0105] This ensures both the longevity and the prevention of peeling of the surface layer 52. More specifically, a thickness of 3 μm or more ensures a sufficient period (life) until wear occurs even if the surface layer 52 is worn. Furthermore, a thickness of 7 μm or less prevents the surface layer 52 from losing its toughness.

[0106] In the hollow guide shaft body 32, the intermediate layer 51 may have a lower hardness on the substrate portion 50 side than on the surface layer 52 side.

[0107] This prevents the difference in hardness between the surface of the intermediate layer 51 facing the substrate 50 and the hardness of the substrate 50 from increasing, and also prevents the difference in hardness between the surface of the intermediate layer 51 facing the surface layer 52 and the hardness of the surface layer 52 from increasing. Therefore, the intermediate layer 51 and the substrate 50 can suitably absorb the impact load acting on the surface layer 52, thereby preventing peeling of the surface layer 52.

[0108] In the hollow guide shaft 32, the surface layer 52 may be a DLC coating.

[0109] This allows the formation of a surface layer 52 with sufficient hardness. In addition, because the DLC coating has a low friction coefficient, it is possible to reduce friction that occurs between the hollow guide shaft 32 and the fibers. This allows the orbital speed of the fibers to be further increased, and therefore the spinning speed of the air spinning device 5 to be further increased.

[0110] In the hollow guide shaft body 32, the surface layer 52 may include at least one of convex portions 62a formed by the attached droplets 61 and concave portions 62b that are traces of the droplets 61 that have fallen off, and the maximum peak height Rp may be greater than 0 μm and not more than 2.0 μm, and the arithmetic mean height Ra may be not more than 0.4 μm.

[0111] This makes it possible to prevent the coefficient of friction between the fibers and the surface layer 52 from increasing due to irregularities formed by droplets that occur when a DLC coating is formed using the arc ion plating method.

[0112] In the hollow guide shaft body 32, the surface layer 52 may have a diameter d1 of the convex portion 62a or a diameter d2 of the concave portion 62b of 1 μm or more and 10 μm or less when viewed from the normal direction.

[0113] This makes it possible to prevent the coefficient of friction between the fibers and the surface layer 52 from increasing due to irregularities formed by droplets that occur when a DLC coating is formed using the arc ion plating method.

[0114] In the hollow guide shaft body 32, the surface layer 52 has a convex portion 62a or a concave portion 62b of 10000 μm. 2 The number of pieces may be 3 or more and 30 or less.

[0115] This makes it possible to prevent the coefficient of friction between the fibers and the surface layer 52 from increasing due to irregularities formed by droplets that occur when a DLC coating is formed using the arc ion plating method.

[0116] In the hollow guide shaft 32, the surface layer 52 may have a width w1 of 5 mm or more at a portion extending from the end edge 39a along the surface of the hollow guide shaft 32 in a direction away from the inlet 40a.

[0117] This allows the area where the fibers come into contact with the hollow guide shaft 32 (fiber contact area) to be covered with the surface layer 52. This prevents the intermediate layer 51 and / or the base material portion 50 of the hollow guide shaft 32 from being worn down due to contact with the fibers.

[0118] In the hollow guide shaft 32, the surface layer 52 may have a width w2 of 2 mm or less at a portion extending from the end edge 39a along the inner wall surface of the fiber passage 39 in a direction away from the inlet 40a.

[0119] The outer surface of the hollow guide shaft 32 (the area excluding the inner wall surface surrounding the fiber passage 39) may be subjected to an impact load due to a collision with another component during maintenance of the air spinning device 5. By limiting the area of ​​the fiber passage 39 that is less susceptible to impact loads and that is covered with the surface layer 52, the process of forming the surface layer 52 is simplified, and the manufacturing cost of the hollow guide shaft 32 is reduced.

[0120] In the hollow guide shaft body 32, the substrate portion 50 may be made of at least one of iron, conductive ceramics, cemented carbide, and stainless steel.

[0121] This allows static electricity generated by friction between the hollow guide shaft body 32 and the fibers to be reliably released.

[0122] The air spinning device 5 includes a hollow guide shaft 32, a swirl chamber forming member (nozzle block 31) in which a swirl chamber 41 in which the fibers swirl is formed, and a fiber guide section (needle 44) that guides the fibers into the swirl chamber 41.

[0123] The hollow guide shaft 32 is easy to handle because peeling of the surface layer 52 is suppressed. Therefore, the air spinning device 5 including the hollow guide shaft 32 is also easy to handle.

[0124] The yarn winding machine 1 includes an air spinning device 5 and a winding section 8 that winds the spun yarn 15 produced by the air spinning device 5 to form a package.

[0125] The yarn winding machine 1 employs an air spinning device 5, and is therefore easy to handle. [Example]

[0126] (First Example) The inventors evaluated the amount of deformation when an impact load was applied to base material parts 50 with intermediate layers 51 of different thicknesses. FIG. 9 is a graph showing the evaluation results of Example 1. In this evaluation, base material parts 50 with intermediate layers 51 of different thicknesses were arranged with the inlet part 40 facing upward, and then a weight was dropped from above, and the drop height of the weight at which a dent was generated was compared. In the graph shown in FIG. 9, the vertical axis represents the drop height (mm) of the weight at which a dent was generated.

[0127] Comparative Example 1 is a substrate part 50 only. Comparative Example 2 is a substrate part 50 on which only a surface layer 52 (DLC coating) is formed. Comparative Example 3 is a substrate part 50 on which a 20 μm thick intermediate layer 51 is coated with a surface layer 52. Comparative Example 4 is a substrate part 50 on which only a 100 μm thick intermediate layer 51 is formed. Comparative Example 5 is a substrate part 50 (i.e., hollow guide shaft body 32) on which a 100 μm thick intermediate layer 51 is coated with a surface layer 52.

[0128] In all the comparative examples, the hardness of the intermediate layer 51 is approximately Hv 1000. The base material 50 is made of SUS304, which has not been subjected to any hardening treatment.

[0129] 9, it was found that the base member 50 having the intermediate layer 51 with a thickness of 100 μm formed thereon had a higher weight drop height at which a dent was generated (i.e., the base member 50 was less likely to have a dent) than the base member 50 having the intermediate layer 51 with a thickness of 20 μm, regardless of whether the surface layer 52 was present or not. This confirmed that the thick intermediate layer 51 can absorb the difference in the amount of elastic deformation between the base member 50 and the surface layer 52 in response to an impact load applied to the surface layer 52.

[0130] (Second Example) The inventors evaluated the effect of the unevenness formed by the droplets on spinning performance. Fig. 10 is a graph showing the evaluation results for Example 2. In this evaluation, the yarn diameter and fluff index of spun yarns produced by an air spinning device 5 equipped with a hollow guide shaft 32 were compared. Fig. 10 shows the yarn diameter and fluff index obtained in this evaluation normalized by the values ​​of a spun yarn produced by an air spinning device using a conventional ceramic hollow guide shaft.

[0131] In Comparative Example 6, a hollow guide shaft 32 was used in which protrusions 62a having a diameter of 13 μm and a height of 2.5 μm were formed on the surface layer 52. In Comparative Example 7, a hollow guide shaft 32 was used in which protrusions 62a having a diameter of 13 μm and a height of 1.0 μm were formed on the surface layer 52. In Comparative Example 8, a hollow guide shaft 32 was used in which protrusions 62a having a diameter of 10 μm and a height of 2.5 μm were formed on the surface layer 52.

[0132] The surface layer 52 of Comparative Example 6 was formed only by the arc ion plating method. The surface layer 52 of Comparative Example 7 was formed by performing the arc ion plating method and then removing part of the protrusions 62a by special shot blasting. The surface layer 52 of Comparative Example 8 was formed by performing the arc ion plating method in a furnace equipped with a filter capable of removing droplets 61.

[0133] As shown in Figure 10, it was confirmed that by using the hollow guide shaft 32 of Comparative Example 7, in which the height of the convex portions 62a is 1.0 μm, and the hollow guide shaft 32 of Comparative Example 8, in which the diameter of the convex portions 62a is 10 μm, both the yarn diameter and the fluff index were improved compared to the hollow guide shaft 32 of Comparative Example 6.

[0134] 2. Second embodiment A hollow guide shaft (not shown) according to the second embodiment will now be described. Like the hollow guide shaft 32, the hollow guide shaft is also used in the air spinning device 5 and the yarn winding machine 1. The main difference between the hollow guide shaft 32 and the hollow guide shaft is the area where the surface layer 52 is formed. In the following description, features that are the same as or correspond to those of the first embodiment will be given the same reference symbols, and description thereof will be omitted as appropriate.

[0135] The hollow guide shaft according to the second embodiment has a fiber passage 39 formed therein, around which fibers subjected to the action of the swirling air current in the air spinning device 5 swirl, and through which fibers twisted by the swirling air current pass. The hollow guide shaft according to the second embodiment includes a conductive substrate 50, an intermediate layer 51 that is harder than the substrate 50 and is provided on the surface of the substrate 50, and a surface layer 52 that is harder than the intermediate layer 51 and is provided on at least a portion of the surface of the intermediate layer 51.

[0136] The surface layer 52 has a width w1 of a portion extending from the end edge 39a along the surface of the hollow guide shaft body 32 toward the large diameter portion of the tapered portion 37, the width w1 being 5 mm or more and 20 mm or less.

[0137] The intermediate layer 51 has a width (not shown) that is wider than that of the surface layer 52 at a portion extending from the end edge 39 a along the surface of the hollow guide shaft body 32 toward the large diameter portion of the tapered portion 37 .

[0138] This allows the portions where the fibers come into contact with the hollow guide shaft 32 (fiber contact portions) to be covered with the surface layer 52. This prevents the intermediate layer 51 and / or the substrate portion 50 of the hollow guide shaft 32 from being worn down due to contact with the fibers. Furthermore, by not covering the portions where the fibers are unlikely to come into contact with the surface layer 52, the process of forming the surface layer 52 is simplified, and the manufacturing costs of the hollow guide shaft 32 are reduced.

[0139] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications are possible without departing from the spirit of the invention. In particular, the multiple embodiments and modifications described in this specification can be combined as needed. [Industrial Applicability]

[0140] The hollow guide shaft can be used in an air spinning device that applies a swirling air flow to a fiber bundle to twist the fiber bundle and produce a spun yarn. [Explanation of symbols]

[0141] 1: Yarn winding machine 2: Spinning unit 3: Yarn splicing cart 4: Draft device 5: Air spinning device 6: Yarn monitoring device 7: Yarn storage device 8: Winding section 9: Sliver 10: Fiber bundle 10a: Core fiber 10b: Inverted fiber 11-14: Draft Roller 15: Spun yarn 16: Cutter 17: Bobbin 18: Package 19: Cradle arm 20: Winding drum 21: Traverse device 22: Traverse Guide 23: Yarn storage roller 25: Electric motor 26: Unit control section 27: Yarn splicing device 28: Suction pipe 29: Suction mouth 30: Fiber guide block 31: Nozzle block 32: Hollow guide shaft 32a: Hollow guide shaft 33: Casing 33a: Upstream casing 33b: Downstream casing 34: Fiber introduction hole 35: Air supply chamber 36: Compressed air supply pipe 37: Tapered section 37a :part 38: Cylindrical part 39: Fiber passage 39a: edge 40: Entrance 40a: Entrance 41: Turning room 42: Tapered chamber 43: Air jet nozzle 44: Needle 50: Base material part 51: Middle class 52: Surface layer 53: Heat-treated layer 54: Nitrided layer 55: Plating layer 61: Droplet 62a: Convex part 62b: recess ND: Normal direction

Claims

1. A hollow guide shaft body in an air spinning device, in which fibers subjected to the action of a swirling air current swirl around the hollow guide shaft body and a fiber passage through which the fibers twisted by the swirling air current pass, A substrate portion; an intermediate layer formed on a surface of the base material, the intermediate layer being harder than the base material; a surface layer that is harder than the intermediate layer and is formed on at least a portion of the surface of the intermediate layer; Equipped with The hardness of the intermediate layer is 1000Hv or more and 1500Hv or less, The thickness of the intermediate layer is 60 μm or more and 200 μm or less Hollow guide shaft.

2. The hardness of the surface layer is 2000Hv or more and 3500Hv or less, The hollow guide shaft according to claim 1 .

3. The thickness of the surface layer is 3 μm or more and 7 μm or less, The hollow guide shaft according to claim 1 or 2.

4. The intermediate layer is the hardness of the substrate side is lower than the hardness of the surface layer side; The hollow guide shaft according to any one of claims 1 to 3.

5. The surface layer is Diamond-like carbon coating The hollow guide shaft according to any one of claims 1 to 4.

6. The surface layer is The surface includes at least one of a convex portion formed by the attached droplets and a concave portion formed by the droplets having fallen off, The maximum peak height Rp is greater than 0 μm and not more than 2.0 μm, and the arithmetic mean height Ra is not more than 0.4 μm. The hollow guide shaft according to any one of claims 1 to 5.

7. The surface layer is the diameter of the convex portion or the diameter of the concave portion is 1 μm or more and 10 μm or less when viewed from the normal direction of the surface layer; The hollow guide shaft according to claim 6.

8. The surface layer is The number of the convex portions or concave portions is 10,000 μm ２ The number of winners is between 3 and 30.

8. The hollow guide shaft according to claim 6 or 7.

9. The surface layer is a width of a portion extending from an edge surrounding the inlet of the fiber passage along the surface of the hollow guide shaft in a direction away from the inlet of the fiber passage being 5 mm or more; The hollow guide shaft according to any one of claims 1 to 8.

10. The surface layer is a width of a portion extending from an edge surrounding the inlet of the fiber passage along an inner wall surface of the fiber passage in a direction away from the inlet of the fiber passage being 2 mm or less; The hollow guide shaft according to claim 9.

11. The substrate portion is Consisting of at least one of iron, conductive ceramics, cemented carbide, and stainless steel; The hollow guide shaft according to any one of claims 1 to 10.

12. A hollow guide shaft according to any one of claims 1 to 11; a swirl chamber forming member in which a swirl chamber in which the fibers swirl is formed; a fiber guide section that guides the fibers into the swirl chamber; An air spinning device comprising:

13. The air spinning device according to claim 12; a winding section that winds the spun yarn produced by the air spinning device to form a package; A yarn winding machine comprising:

14. A hollow guide shaft body in an air spinning device, in which fibers subjected to the action of a swirling air current swirl around the hollow guide shaft body and a fiber passage through which the fibers twisted by the swirling air current pass, A substrate portion; an intermediate layer that is harder than the base material and is provided on the surface of the base material; a surface layer that is harder than the intermediate layer and is provided on at least a portion of the surface of the base material, and is provided on the surface of the intermediate layer; Equipped with The surface layer is a width of a portion extending from an edge surrounding the inlet of the fiber passage along the surface of the hollow guide shaft in a direction away from the inlet of the fiber passage is 5 mm or more and 20 mm or less; The intermediate layer is The width from the edge surrounding the entrance of the fiber passage is wider than that of the surface layer. Hollow guide shaft.

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