Inner cylindrical body of drafting roller, roller member of drafting roller, drafting roller, drafting device, and air-jet spinning machine

Abstract

 A front top roller (20) includes a roller member (26) that is rotatably supported via a bearing member (28). The roller member (26) includes an outer cylindrical body (38) made of rubber and an inner cylindrical body (40) arranged inside the outer cylindrical body (38). A coating (53) is applied on an inner peripheral surface of the inner cylindrical body (40).

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

[0001] The present invention mainly relates to a configuration of a drafting roller for use in a drafting device of a spinning machine.

2. Description of the Related Art

[0002] A typical spinning machine includes a drafting device that stretches a sliver, which serves as a base material of a yarn, until the sliver reaches a state that is appropriate for spinning. Such a drafting device includes plural drafting rollers. In the drafting device, the sliver is nipped between the rotating drafting rollers and stretched until a fiber bundle of a predetermined thickness is formed.

[0003] The drafting roller includes a cylindrical roller member and a shaft member (arbor). A bearing that rotatably supports the roller member is mounted on the shaft member. An outer peripheral surface of the roller member of the drafting roller is made of rubber, and a metal cylindrical body (sleeve) is arranged on an inner periphery of the roller member. Such a structure is disclosed, for example, in Japanese Patent Application Laid-open No. H11-247036. In the structure disclosed in this patent document, bearings (bearings 20 and 21) are arranged between a cylindrical body of the roller member (roller cylindrical body 12) and a shaft member (shaft 10). The cylindrical body of the roller member is fitted onto the bearings and thereby, the roller member is supported to be rotatable relative to the shaft member.

[0004] The rubber on the outer peripheral surface of the roller member tends to wear out with use. Hence, it is preferable that the roller member is easy to replace. To achieve this, in the conventional drafting roller, a small gap is secured between the cylindrical body of the roller member and the bearings. In this structure, the worn out roller member can be easily pulled out and removed from the bearings, and a new roller member (unworn) can then be easily fitted by inserting the roller member onto the bearings.

[0005] However, along with an increased speed of the spinning devices in recent years, the drafting rollers are required to rotate at a higher rotational speed, resulting in fretting (wearing out) between the cylindrical body of the roller member and the bearings of the arbor.

[0006] Fretting can be prevented by not leaving a gap between the cylindrical body of the roller member and the bearings of the arbor. However, the absence of such a gap will not allow for easy replaceability of the roller member.

SUMMARY OF THE INVENTION

[0007] It is an object of the present invention to provide a structure that prevents fretting without adversely affecting the replaceability of the drafting roller.

[0008] An inner cylindrical body according to an aspect of the present invention is arranged in a drafting roller inside an outer cylindrical body of a roller member that is rotatably supported via a bearing, and the outer cylindrical body is made of rubber. A coating is applied on at least a portion of an inner peripheral surface of the inner cylindrical body.

[0009] A roller member according to another aspect of the present invention includes the above inner cylindrical body, and an outer cylindrical body that is made of rubber and that is arranged outside the inner cylindrical body.

[0010] A drafting roller according to still another aspect of the present invention includes the above roller member, and an arbor that includes a bearing that freely rotatably supports the roller member.

[0011] A drafting roller according to still another aspect of the present invention includes a cylindrical roller member and an arbor that rotatably supports the roller member. A coating is applied on at least the portion of the outer peripheral surface of the arbor.

[0012] A drafting device according to still another aspect of the present invention includes a roller pair constituted by the above drafting roller and a roller arranged opposing the drafting roller.

[0013] An air-jet spinning machine according to still another aspect of the prevent invention includes the above drafting device, an air-jet spinning device that twists the fiber bundle supplied from the drafting device by the action of a swirling air current to form a spun yarn, and a winding device that winds the spun yarn.

[0014] The above and other objects, features, advantages and the technical and industrial significance of this invention will be better understood by reading the following detailed description of presently preferred embodiments of the invention, when considered in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] 

FIG. 1 is a front view of an overall structure of a spinning frame according to an embodiment of the present invention;

FIG. 2 is a side view of a spinning unit;

FIG. 3 is a top cross-sectional view of a front top roller;

FIG. 4 is a top cross-sectional view showing an arbor and a roller member in a separated state; and

FIG. 5 is a top cross-sectional view showing an outer cylindrical body and an intermediate cylindrical body in a separated state from an inner cylindrical body.

DETAILED DESCRIPTION

[0016] Exemplary embodiments of a spinning frame (air-jet spinning machine) according to the present invention are explained in detail below with reference to the accompanying drawings. As shown in FIG. 1, a spinning frame 1 that is a spinning machine includes plural spinning units 2 arranged side by side and a yarn joining carrier 3.

[0017] As shown in FIG. 1, each of the spinning units 2 includes, arranged sequentially from upstream to downstream, a drafting device 7, a spinning device (spinning section) 9, a yarn pooling device 12, and a winding device 13. In this specification, the terms "upstream" and "downstream" refer to upstream and downstream in a running direction of a fiber bundle and a yarn during spinning. The spinning device 9 of each of the spinning units 2 spins a fiber bundle 8 conveyed from the drafting device 7 to form a spun yarn 10. The spun yarn 10 is wound by the winding device 13 to form a package 45.

[0018] The drafting device 7 is arranged near an upper edge of the spinning frame 1. The drafting device 7 includes plural drafting rollers 16, 17, 19, 20, 66, 67, 69, and 70.

[0019] The drafting rollers 66, 67, 69, and 70 are made of metal and are called bottom rollers. Each of the bottom rollers 66, 67, 69, and 70 is driven to rotate about an axis thereof by a not shown driving source. The drafting device 7 according to the present embodiment includes four bottom rollers, which are, sequentially from upstream, a back bottom roller 66, a third bottom roller 67, a middle bottom roller 69 with a rubber apron belt 68 stretched thereon, and a front bottom roller 70.

[0020] The drafting rollers 16, 17, 19, and 20 are called top rollers. The drafting device 7 according to the present embodiment includes four top rollers, which are, sequentially from upstream, a back top roller 16, a third top roller 17, a middle top roller 19 with an apron belt 18 stretched thereon, and a front top roller 20.

[0021] FIG. 3 is a drawing of a structure of the front top roller 20. The structures of the other top rollers 16, 17, and 19 are identical to that of the front top roller 20. As shown in FIG. 3, the top roller 20 includes a cylindrical roller member 26 and an arbor (shaft member) 27. The outer peripheral surface of the roller member 26 is made of rubber. A bearing member 28 that rotatably supports the roller member 26 is mounted on the arbor 27.

[0022] The bottom rollers and top rollers are arranged as pairs. That is, the drafting device 7 according to the present embodiment is configured as a so-called four-line drafting device that includes four drafting roller pairs, namely, a back roller pair constituted by the drafting rollers 16 and 66, a third roller pair constituted by the drafting rollers 17 and 67, a middle roller pair constituted by the drafting rollers 19 and 69, and a front roller pair constituted by the drafting rollers 20 and 70.

[0023] The top roller and the bottom roller of each of the drafting roller pairs are arranged opposite to each other. Each of the top rollers 16, 17, 19, and 20 is arranged more to the front of the device than their respective opposing bottom rollers 66, 67, 69, and 70. The drafting device 7 further includes a not shown urging member that urges each of the top rollers 16, 17, 19, and 20 toward their respective opposing bottom rollers 66, 67, 69, and 70. With this structure, the outer peripheral surface of the roller member 26 of each of the top rollers 16, 17, 19, and 20 is pressed against the outer peripheral surface of each of the bottom rollers 66, 67, 69, and 70, respectively. Hence, when the bottom rollers 66, 67, 69, and 70 are driven to rotate, the opposing roller members 26 of the top rollers 16, 17, 19, and 20 that are in contact with the bottom rollers 66, 67, 69, and 70 are also driven to rotate.

[0024] In such a drafting device 7, the rotating drafting roller pairs nip a sliver 15 therebetween and convey it downstream. In the drafting device 7, the rotational speed of each drafting roller pair is higher than the rotational speed of the adjacent drafting roller pair upstream thereof. Hence, the sliver 15 is stretched while being conveyed by the drafting roller pairs, and converted into the fiber bundle 8 having a predetermined width.

[0025] The spinning device 9 is arranged immediately downstream of the front roller pair. The fiber bundle 8 is supplied from the drafting device 7 to the spinning device 9. The spinning device 9 twists the fiber bundle 8 supplied from the drafting device 7 to create the spun yarn 10. In the present embodiment, an air-jet spinning device that twists the fiber bundle 8 by using a swirling air current has been used.

[0026] The winding device 13 is arranged downstream of the spinning device 9. The winding device 13 includes a cradle arm 71 that is supported to be swingable about a shaft 73. The cradle arm 71 rotatably supports a bobbin 48 onto which the spun yarn 10 is wound.

[0027] The winding device 13 includes a winding drum 72 and a traverse device 75. The winding drum 72 is driven while being in contact with the outer peripheral surface of the bobbin 48 or the outer peripheral surface of the package 45 that is formed by winding the spun yarn 10 onto an outer peripheral surface of the bobbin 48. The traverse device 75 includes a traverse guide 76 that is engageable with the spun yarn 10. By driving the winding drum 72 with a not shown electric motor while causing the traverse guide 76 to move back and forth with a not shown driving device, the winding device 13 causes the package 45 that is in contact with the winding drum 72 to rotate and winds the spun yarn 10 onto the bobbin 48 while traversing the spun yarn 10.

[0028] The yarn pooling device 12 is arranged between the spinning device 9 and the winding device 13. As shown in FIG. 2, the yarn pooling device 12 includes a yarn pooling roller 14 and an electric motor 25 that drives the yarn pooling roller 14 to rotate.

[0029] A certain amount of the spun yarn 10 can be wound on an outer peripheral surface of the yarn pooling roller 14 to temporarily pool the yarn. Because the spun yarn 10 can be temporarily pooled in the yarn pooling device 12, the yarn pooling device 12 can be made to function as a kind of a buffer. The buffering function of the yarn pooling device 12 prevents troubles (for example, slackening of the spun yarn 10) that can occur because of a mismatch in a spinning speed of the spinning device 9 and a winding speed of the winding device 13 due to some reason.

[0030] A yarn clearer (yarn quality measuring device) 52 is arranged between the spinning device 9 and the yarn pooling device 12. The spun yarn 10 that is spun in the spinning device 9 passes through the yarn clearer 52 before being wound in the yarn pooling device 12. The yarn clearer 52 monitors the running spun yarn 10 with a not shown optical sensor. When the optical sensor detects a yarn defect (a portion of the spun yarn 10 having an abnormal thickness) in the spun yarn 10, the yarn clearer 52 transmits a yarn defect detection signal to a not shown unit controller. The sensor of the yarn clearer 52 is not limited to the optical sensor; it can be an electrostatic capacitive sensor. Moreover, the yarn clearer 52 can also detect foreign substance included in the spun yarn 10 as a yarn defect.

[0031] As shown in FIGS. 1 and 2, the yarn joining carrier 3 includes a splicer (yarn joining device) 43 and yarn catching members 44 and 46. When yarn cut or yarn breakage occurs in a certain spinning unit 2, the yarn joining carrier 3 travels up to that spinning unit 2. Then, the yarn joining carrier 3 catches the cut ends of the spun yarn 10 by using the yarn catching members 44 and 46 and guides the yarn ends to the splicer 43. The splicer 43 joins the guided yarn ends together (yarn joining).

[0032] The front top roller 20 of the drafting device 7 is explained below in detail.

[0033] As mentioned above, the front top roller 20 includes the roller member 26 and the arbor 27.

[0034] As shown in FIG. 4, the arbor 27 includes a shaft member 29 and a bearing member 28. The bearing member 28 is arranged at the end of the shaft member 29. In the present embodiment, the bearing member 28 is arranged at each end of the arbor 27. That is, the arbor 27 includes two bearing members 28. Only one bearing member 28, however, is shown in FIGS. 3 and 4.

[0035] As shown in FIG. 4, the bearing member 28 includes two bearings 30 and 31 and a spacer 32. Each of the bearings 30 and 31 has a known configuration in which a rotating body is arranged between an outer ring and an inner ring. The outer ring, the inner ring, and the rotating body of each of the bearings 30 and 31 are made of metal. The spacer 32 is arranged between the outer ring of the bearing 30 and the outer ring of the bearing 31.

[0036] A washer 33 is fixed to an end face of the shaft member 29 with a bolt 51. A pressure receiving surface 34 that opposes the washer 33 is formed in the shaft member 29. The inner ring of the bearing 30 and the inner ring of the bearing 31 are arranged between the pressure receiving surface 34 and the washer 33. An urging member 35 (concretely, a compression coil spring) is arranged between the inner ring of the bearing 30 and the inner ring of the bearing 31. By the action of the urging force of the urging member 35, the inner ring of the bearing 30 presses against the pressure receiving surface 34, and the inner ring of the bearing 31 presses against the washer 33. With the above structure, the inner ring of the bearing 30 and the inner ring of the bearing 31 are fixed to the shaft member 29.

[0037] The spacer 32 is a substantially cylindrical member made of metal. An outer diameter of the spacer 32 is substantially identical to outer diameters of the outer rings of the bearings 30 and 31. With this structure, as shown in FIG. 4, the outer peripheral surface of the outer ring of the bearing 30, the outer peripheral surface of the outer ring of the bearing 31 and the outer peripheral surface of the spacer 32 are substantially flush with each other. Accordingly, the outer peripheral surface of the outer ring of the bearing 30, the outer peripheral surface of the outer ring of the bearing 31 and the outer peripheral surface of the spacer 32 are together referred to as an "outer peripheral surface of the bearing member 28". Because the outer ring of the bearing 30, the outer ring of the bearing 31, and the spacer 32 are made of metal, the outer peripheral surface of the bearing member 28 can be said to be made of metal. In the present embodiment, the outer peripheral surface of the bearing member 28 has no coating (later-explained). The spacer 32 rotates integrally with the outer ring of the bearing 30 and the outer ring of the bearing 31. A C ring 37 is fitted onto the outer periphery of the spacer 32.

[0038] The roller member 26 is overall cylindrical and is constituted by plural concentric layers. As shown in FIG. 4, the roller member 26 according to the present embodiment includes, sequentially from outer periphery, an outer cylindrical body 38, an intermediate cylindrical body 39, and an inner cylindrical body 40.

[0039] The outer cylindrical body 38 is made of rubber and is substantially cylindrical. The outer cylindrical body 38 is directly in contact with the sliver 15.

[0040] The inner cylindrical body 40 is arranged on the inner periphery of the outer cylindrical body 38. The inner cylindrical body 40 is made of metal (in the present embodiment, carbon steel for machine structure) and is substantially cylindrical.

[0041] The inner cylindrical body 40 is longer (the length in its axial direction) than the outer cylindrical body 38. Accordingly, the inner cylindrical body 40 includes a part that is located on the inner periphery of the outer cylindrical body 38 and a part that projects along the axial direction from the end face of the outer cylindrical body 38. As shown in FIG. 4, the part of the inner cylindrical body 40 that is located on the inner periphery of the outer cylindrical body 38 is called an inner peripheral portion 41 and the part of the inner cylindrical body 40 that projects along the axial direction from the end face of the outer cylindrical body 38 is called a projecting portion 42. Furthermore, as shown in FIG. 3, the roller member 26 is arranged such that the projecting portion 42 projects towards the side opposite to the end face of the shaft member 29.

[0042] In the roller member 26, a substantially cylindrical intermediate cylindrical body 39 is arranged between the inner peripheral portion 41 of the inner cylindrical body 40 and the outer cylindrical body 38. The intermediate cylindrical body 39 is made of metal (in the present embodiment, the metal is aluminium) and is substantially cylindrical. The intermediate cylindrical body 39 is bonded to the inner peripheral surface of the outer cylindrical body 38 in an appropriate manner. Furthermore, the intermediate cylindrical body 39 is fitted onto the outer peripheral surface of the inner peripheral portion 41 of the inner cylindrical body 40.

[0043] In the present specification, the term "cylindrical" or "cylindrical body" is not limited to a cylindrical shape with a perfect circular cross-section but also includes a wide range of rotor-shaped bodies having an inner peripheral surface and an outer peripheral surface. Accordingly, even if steps and/or grooves are formed on the outer peripheral surface and/or the inner peripheral surface of the outer cylindrical body 38 or the intermediate cylindrical body 39 or the inner cylindrical body 40, they would still be referred to as "cylindrical" or "cylindrical body". For example, as shown in FIG. 4, steps are formed on the outer peripheral surface of the outer cylindrical body 38 according to the present embodiment.

[0044] As shown in FIG. 3, in the front top roller 20, the bearing member 28 is arranged on the inner periphery of the inner peripheral portion 41 of the inner cylindrical body 40. The outer peripheral surface of the bearing member 28 almost touches the inner peripheral surface of the inner peripheral portion 41 of the inner cylindrical body 40. With this structure, the roller member 26 is rotatably supported by the bearing member 28.

[0045] A small gap is secured between the outer peripheral surface of the bearing member 28 and the inner peripheral surface of the inner cylindrical body 40. This gap allows the roller member 26 to be easily removed from and fitted onto the bearing member 28 (indicated by the bold arrow in FIG. 4).

[0046] As shown in FIG. 4, a positioning groove 47 is formed on the inner peripheral surface of the inner peripheral portion 41. The C ring 37 of the bearing member 28 is fitted into the positioning groove 47. With this structure, the roller member 26 is positioned relative to the bearing member 28 along the axial direction (the state shown in FIG. 3).

[0047] As shown in FIG. 3, a cap 49 that covers an end face portion of the front top roller 20 is fitted onto the roller member 26. An O ring 50 is arranged on the outer periphery of the shaft member 29 on the inner side of the projecting portion 42 of the inner cylindrical body 40. The cap 49 and the O ring 50 prevent yarn waste, and the like, from entering the bearing member 28.

[0048] Some features of the present embodiment are explained below.

[0049] A coating 53 is applied on the inner peripheral surface of the inner cylindrical body 40 of the roller member 26 according to the present embodiment. In FIG. 5, the portions where the coating 53 is applied are indicated by the bold dotted lines. A material that is slippery (having low resistance) is used for the coating 53. Accordingly, the portion where the coating 53 is applied has a relatively lower coefficient of friction than the inner peripheral surface of the inner cylindrical body 40 prior to the application of the coating 53.

[0050] The type of the coating 53 is not particularly limited. For example, a film of solid lubricant (dry coating film lubricant) that has excellent lubricity, such as molybdenum disulfide, graphite, fluorine compounds, and the like, can be used as the coating 53. Because the solid lubricants are typically non-metallic, the portion where the coating 53 is applied has a different color than the original color (metallic luster) of the inner cylindrical body 40. For example, the coated portion looks black when molybdenum disulfide or graphite is used and looks white or orange when a fluorine compound is used. By using a coating of a non-metallic solid lubricant, the coated portion can be easily differentiated visually from the non-coated portion. This allows easy detection of any peeling of the coating 53.

[0051] The method of application of the coating 53 on the inner cylindrical body 40 is not particularly limited. Known methods such as spraying and/or dipping can be used to apply the coating.

[0052] As explained above, by applying the coating 53 on the inner peripheral surface of the inner cylindrical body 40, the two metal layers (the inner cylindrical body 40 and the bearing member 28) can be prevented from coming into direct contact, and the friction between the inner cylindrical body 40 and the bearing member 28 can be reduced. With this structure, fretting between the inner cylindrical body 40 and the bearing member 28 can be prevented.

[0053] From the viewpoint of preventing the two metal layers from coming into direct contact and to lower the friction, for example, grease can be applied between the inner cylindrical body 40 and the bearing member 28. However, this would necessitate application of grease every time the roller member 26 is to be replaced, and therefore cost a user time and effort. The solid lubricant as the coating 53, being semi-permanent, is preferable as it saves user time and effort.

[0054] From the viewpoint of preventing fretting between the inner cylindrical body 40 and the bearing member 28, the coating 53 can be applied on the portion of the inner cylindrical body 40 that comes into contact with the bearing member 28 during rotation. Concretely, the coating 53 can be applied only on the inner peripheral surface of the inner peripheral portion 41 of the inner cylindrical body 40. That is, the coating 53 need not be applied on the inner peripheral surface of the projecting portion 42 of the inner cylindrical body 40. By applying the coating only on the required portion, coating material can be saved.

[0055] However, in the present embodiment, as shown in FIG. 5, the coating 53 is applied on the inner peripheral surface of the projecting portion 42 of the inner cylindrical body 40. Even though the coating 53 on this portion does not have a bearing on the prevention of fretting, it can be expected to be effective in improving the ease of replaceability of the roller member 26. That is, when the roller member 26 is fitted onto the bearing member 28, as indicated by the bold double-headed arrow in FIG. 4, the bearing member 28 is inserted inside the inner cylindrical body 40 from the projecting portion 42 side of the inner cylindrical body 40. Accordingly, if the coating 53 is also applied on the inner peripheral surface of the projecting portion 42 of the inner cylindrical body 40 as it is done in the present embodiment, the bearing member 28 can be easily inserted into the inner cylindrical body 40.

[0056] A technology related to coating in the field of drafting rollers is disclosed, for example, in Japanese Translation of PCT International Publication for Patent Application No. 2012-508828. However, this patent document discloses a top roller with a coating in the form of a non-abrasive non-corrosive member applied on a shaft body (middle shaft member 2). The coating disclosed in this patent document is not applied on the portion that is in contact with a rotating roller member (in the first place, it is not mentioned in that application that the roller member is replaceable). Accordingly, the coating mentioned in this patent document has no relevance to prevention of fretting.

[0057] Because of the coating 53, the inner cylindrical body 40 of the front top roller 20 according to the present embodiment is more expensive than the conventional inner cylindrical body (that is devoid of coating). Consequently, if the inner cylindrical body 40 can be reused when replacing the roller member 26, it would be advantageous from cost perspective. If, during replacement, the outer cylindrical body 38 (and the intermediate cylindrical body 39 that is bonded to the outer cylindrical body 38) that is worn out due to use can be removed from the inner cylindrical body 40, the inner cylindrical body 40 can be reused.

[0058] However, because the inner cylindrical body 40 is fitted onto the intermediate cylindrical body 39, in the conventional drafting roller, it is not easy to remove the intermediate cylindrical body 39 (and the outer cylindrical body 38 bonded to the intermediate cylindrical body 39) from the inner cylindrical body 40 during replacement.

[0059] In the present embodiment, as shown in FIG. 5, the coating 53 is also applied on the outer peripheral surface of the inner cylindrical body 40. Consequently, a frictional resistance between the inner cylindrical body 40 and the intermediate cylindrical body 39 fitted onto the outside of the inner cylindrical body 40 is reduced. Accordingly, the intermediate cylindrical body 39 (and the outer cylindrical body 38 bonded to the intermediate cylindrical body 39) can be easily removed from the inner cylindrical body 40 (as indicated by the bold arrow in FIG. 5). Consequently, the inner cylindrical body 40 can be reused, and thereby a replacement cost of the roller member 26 can be reduced.

[0060] As explained above, in the present embodiment, the coating 53 is applied on both the inner peripheral surface and the outer peripheral surface of the inner cylindrical body 40. Consequently, multiple advantages, namely, prevention of fretting, easy replaceability of the roller member 26, reuse of the inner cylindrical body 40, and the resulting replacement cost reduction, can be gained. Furthermore, because the coating 53 is applied on the entire inner cylindrical body 40, there is no need to apply a mask during the coating operation. Consequently, the coating operation can be easily performed and a manufacturing cost of the inner cylindrical body 40 can be reduced.

[0061] As explained above, the coating 53 is applied on the inner peripheral surface of the inner cylindrical body 40 according to the present embodiment. By applying the coating 53 on the inner peripheral surface of the inner cylindrical body 40, fretting between the inner cylindrical body 40 and the bearing member 28 can be prevented.

[0062] As explained above, the portion where the coating 53 is applied has less coefficient of friction than the inner peripheral surface of the inner cylindrical body 40 devoid of the coating 53. By applying the coating 53 that is slippery, friction between the inner cylindrical body 40 and the bearing member 28 can be reduced, and thereby fretting between the inner cylindrical body 40 and the bearing member 28 can be prevented.

[0063] Furthermore, as explained above, the inner cylindrical body 40 is made of metal and the coating 53 is non-metallic. Consequently, the portion where the coating 53 is applied has a different color than the original color (metallic luster) of the inner cylindrical body 40. Accordingly, any peeling of the coating 53 can be easily confirmed visually.

[0064] As explained above, it is preferable that the material of the coating 53 of the inner cylindrical body 40 is at least any one of molybdenum disulfide, graphite, and fluorine compounds. Because the coating 53 of any of the above coating agents is slippery and durable, fretting between the inner cylindrical body 40 and the bearing member 28 can be reliably prevented.

[0065] As explained above, the coating 53 is also applied on the outer peripheral surface of the inner cylindrical body 40. Consequently, the outer cylindrical body 38 (and the intermediate cylindrical body 39 bonded to the outer cylindrical body 38) can be easily removed from the inner cylindrical body 40. Consequently, the inner cylindrical body 40 can be reused. Furthermore, because the coating 53 is applied on the entire inner cylindrical body 40, there is no need to apply a mask, and the like, during the coating operation. Consequently, the coating operation can be simplified.

[0066] As explained above, the roller member 26 according to the present embodiment includes the inner cylindrical body 40, and the outer cylindrical body 38 that is made of rubber and that is arranged outside of the inner cylindrical body 40. By configuring the roller member 26 to include the inner cylindrical body 40 with the coating 53 applied on the inner peripheral surface thereof, fretting can be prevented.

[0067] As explained above, the front top roller 20 according to the present embodiment includes the roller member 26, and the arbor 27 that includes the bearing member 28 that rotatably supports the roller member 26. By configuring the front top roller 20 in this manner, fretting between the inner cylindrical body 40 of the roller member 26 and the bearing member 28 is prevented.

[0068] As explained above, the drafting device 7 according to the present embodiment includes the roller pair constituted by the front top roller 20 and the front bottom roller 70 that opposes the front top roller 20. By configuring the drafting device 7 in this manner, fretting of the front top roller 20 is prevented, and thereby, the front top roller 20 can be rotated smoothly and at a uniform speed. Consequently, a quality of the fiber bundle 8 being formed by the drafting device 7 can be improved.

[0069] As explained above, the spinning frame 1 according to the present embodiment includes the drafting device 7, the air-jet spinning device 9 that twists the fiber bundle 8 supplied from the drafting device 7 by the action of the swirling air current to form the spun yarn 10, and the winding device 13 that winds the spun yarn 10.

[0070] The spinning speed of an air-jet spinning machine is high and consequently, the rotational speed of the drafting roller also tends to be high, leading to fretting of the drafting roller. By adopting the configuration of the air-jet spinning machine according to the present invention, prevention of fretting of the drafting roller can be ideally demonstrated.

[0071] Exemplary embodiments of the present invention are explained above; however, the structures explained above can be modified as follows.

[0072] In the drafting roller according to the above embodiment, the coating 53 is applied on the inner peripheral surface (inner peripheral surface of the inner cylindrical body 40) of the roller member 26. Instead of the inner peripheral surface of the roller member 26 or in addition to the inner peripheral surface of the roller member 26, the coating 53 can be applied on the arbor 27. That is, by applying the coating 53 on the portion of the outer peripheral surface of the arbor 27 that comes into contact with the inner peripheral surface of the rotating roller member 26 (concretely, the outer peripheral surface of the bearing member 28), prevention of fretting in a manner similar to that of the above embodiment can be effectively demonstrated. However, the coating of the outer peripheral surface of the bearing member 28 will make the bearings 30 and 31 exclusive components and disadvantageously increase the overall cost of the spinning frame 1. Accordingly, it is preferable from cost perspective that the coating 53 is applied only on the inner peripheral surface of the roller member 26.

[0073] When coating the outer peripheral surface of the arbor 27 (concretely, the outer peripheral surface of the bearing member 28), a material that is slippery should be used for coating, as in the above embodiment. A non-metallic coating, as in the above embodiment, would be preferable because any peeling of the coating can be easily confirmed visually. Concretely, it is preferable that a coating of a coating film (dry coating film lubricant) of a solid lubricant that has excellent lubricity, such as molybdenum disulfide, graphite, fluorine compounds, and the like, is applied on the outer peripheral surface of the arbor 27.

[0074] The intermediate cylindrical body 39 can be omitted and the inner cylindrical body 40 can be directly arranged inside the outer cylindrical body 38.

[0075] The configuration of the bearing member 28 is not limited to what is shown in the accompanying drawings and can be suitably modified.

[0076] In the above embodiment, mainly, the front top roller 20 is explained. The structures of other top rollers 16, 17, and 19 are also identical to that of the front top roller 20. Accordingly, as in the front top roller 20, fretting can also be prevented in the other top rollers 16, 17, and 19 by applying the coating 53 on the inner cylindrical body 40 and/or the arbor 27. However, among the four top rollers 16, 17, 19, and 20 of the drafting device 7, the front top roller 20 has the highest rotational speed, and is therefore most prone to fretting. Accordingly, by applying the coating 53 on the inner cylindrical body 40 and/or the arbor 27 of the front top roller 20, as in the above embodiment, the advantage of prevention of fretting can be particularly ideally demonstrated.

[0077] An O ring, or a similar sealing member, can be arranged between the outer ring of the bearing 30 and the spacer 32, and the outer ring of the bearing 31 and the spacer 32. The gaps between the outer ring of the bearing 30 and the spacer 32, and the outer ring of the bearing 31 and the spacer 32 can be filled by the O ring.

[0078] An inner cylindrical body according to an aspect of the present invention is arranged in a drafting roller inside an outer cylindrical body of a roller member that is rotatably supported via a bearing, and the outer cylindrical body is made of rubber. A coating is applied on at least a portion of an inner peripheral surface of the inner cylindrical body.

[0079] By applying the coating on the inner peripheral surface of the inner cylindrical body, fretting between the inner cylindrical body and the bearing can be prevented.

[0080] It is preferable that the portion of the inner peripheral surface of the inner cylindrical body where the coating is applied has a lower coefficient of friction than the portion of the inner peripheral surface of the inner cylindrical body devoid of the coating.

[0081] That is, the material used for the coating is slippery. By using a slippery material for the coating, a friction between the inner cylindrical body and the bearing can be reduced, and thereby, fretting between the inner cylindrical body and the bearing can be prevented.

[0082] It is preferable that the inner cylindrical body is made of metal, and the coating has a non-metallic color.

[0083] When a non-metallic coating material is used, the coating-applied portion has a different color than the original color (metallic luster) of the inner cylindrical body. Consequently, any peeling of the coating can be easily confirmed visually.

[0084] In the inner cylindrical body, it is preferable that a material used for the coating is at least any one of molybdenum disulfide, graphite, and fluorine compounds.

[0085] Because the coating of any of the above coating agents is slippery and durable, fretting between the inner cylindrical body and the bearing can be reliably prevented.

[0086] A coating can be applied also on at least a portion of an outer peripheral surface of the inner cylindrical body.

[0087] By also applying the coating on the outer peripheral surface of the inner cylindrical body, the outer cylindrical body can be easily removed from the inner cylindrical body. Consequently, the inner cylindrical body can be reused. Furthermore, because the coating is applied on the entire inner cylindrical body, there is no need to apply a mask and the like during the coating operation. Consequently, the coating operation can be simplified.

[0088] A roller member according to another aspect of the present invention includes the above inner cylindrical body, and an outer cylindrical body that is made of rubber and that is arranged outside the inner cylindrical body.

[0089] By configuring the roller member to include the inner cylindrical body with the coating applied on the inner peripheral surface thereof, fretting can be prevented.

[0090] A drafting roller according to still another aspect of the present invention includes the above roller member, and an arbor that includes a bearing that freely rotatably supports the roller member.

[0091] By configuring the drafting roller in this manner, fretting between the inner cylindrical body of the roller member and the bearing is prevented.

[0092] A drafting roller according to still another aspect of the present invention includes a cylindrical roller member and an arbor that rotatably supports the roller member. A coating is applied on at least the portion of the outer peripheral surface of the arbor.

[0093] In this manner, the coating can be applied on the side of the arbor that supports the roller member. By configuring the drafting roller in this manner, fretting between the arbor and the roller member can be prevented.

[0094] It is preferable that, in the drafting roller, the portion of the outer peripheral surface of the arbor where the coating is applied has a lower coefficient of friction than the outer peripheral surface of the arbor devoid of the coating.

[0095] It is preferable that, in the drafting roller, the outer peripheral surface of the arbor is made of metal, and the coating has a non-metallic color.

[0096] It is preferable that, in the drafting roller, a material used for the coating is at least any one of molybdenum disulfide, graphite, and fluorine compounds.

[0097] A drafting device according to still another aspect of the present invention includes a roller pair constituted by the above drafting roller and a roller arranged opposing the drafting roller.

[0098] By configuring the drafting device in this manner, fretting of the drafting roller can be prevented, and thereby, the roller member of the drafting roller can be rotated smoothly and at a uniform speed. Consequently, a quality of the fiber bundle being formed by the drafting device can be improved.

[0099] An air-jet spinning machine according to still another aspect of the prevent invention includes the above drafting device, an air-jet spinning device that twists the fiber bundle supplied from the drafting device by the action of a swirling air current to form a spun yarn, and a winding device that winds the spun yarn.

[0100] A spinning speed of the air-jet spinning machine is high and consequently, the rotational speed of the drafting roller also tends to be high, leading to fretting of the drafting roller. By adopting the configuration of the air-jet spinning machine according to the present invention, prevention of fretting of the drafting roller can be ideally demonstrated.

[0101] Although the invention has been described with respect to specific embodiments for a complete and clear disclosure, the appended claims are not to be thus limited but are to be construed as embodying all modifications and alternative constructions that may occur to one skilled in the art that fairly fall within the basic teaching of the claims.

Claims

1. An inner cylindrical body(40) arranged in a drafting roller(20) inside an outer cylindrical body(38) of a roller member (26) that is rotatably supported via a bearing(30,31), the outer cylindrical body being made of rubber, wherein
a coating(53) is applied on at least a portion of an inner peripheral surface of the inner cylindrical body(40).

2. The inner cylindrical body(40) as claimed in Claim 1, wherein the portion of the inner peripheral surface of the inner cylindrical body(40) where the coating(53) is applied has a lower coefficient of friction than a portion of the inner peripheral surface of the inner cylindrical body(40) devoid of the coating(53).

3. The inner cylindrical body(40) as claimed in Claim 1 or 2, wherein the inner cylindrical body (40) is made of metal, and
the coating(53) has a non-metallic color.

4. The inner cylindrical body (40) as claimed in any one of Claims 1 to 3, wherein a material used for the coating (53) is at least any one of molybdenum disulfide, graphite, and fluorine compounds.

5. The inner cylindrical body (40) as claimed in any one of Claims 1 to 4, wherein a coating (53) is applied also on at least a portion of an outer peripheral surface of the inner cylindrical body(40).

6. A roller member(26) comprising:

the inner cylindrical body(40) as claimed in any one of Claims 1 to 5; and

an outer cylindrical body(38) that is made of rubber and that is arranged outside the inner cylindrical body(40).

7. A drafting roller(20) comprising:

the roller member(26) as claimed in Claim 6; and

an arbor (27) that includes a bearing(30,31) that freely rotatably supports the roller member.

8. A drafting roller(20) comprising:

a cylindrical roller member(26); and

an arbor(27) that rotatably supports the roller member(26),

wherein a coating(53) is applied on at least a portion of an outer peripheral surface of the arbor(27) that comes into contact with an inner peripheral surface of the roller member (26).

9. The drafting roller(20) as claimed in Claim 8, wherein the portion of the outer peripheral surface of the arbor(27) where the coating (53) is applied has a lower coefficient of friction than a portion of the outer peripheral surface of the arbor (27) devoid of the coating(53).

10. The drafting roller(20) as claimed in Claim 8 or 9, wherein
the outer peripheral surface of the arbor(27) is made of metal, and
the coating(53) has a non-metallic color.

11. The drafting roller(20) as claimed in any one of Claims 8 to 10, wherein a material used for the coating(53) is at least any one of molybdenum disulfide, graphite, and fluorine compounds.

12. A drafting device(7) comprising a roller pair(20,70) that includes
the drafting roller(20) as claimed in any one of Claims 7 to 11, and
a roller(70) that is arranged opposing the drafting roller.

13. An air-jet spinning machine(1) comprising:

the drafting device(7) as claimed in Claim 12;

an air-jet spinning device(9) that twists a fiber bundle supplied from the drafting device(7) by an action of a swirling air current and forms a spun yarn; and

a winding device(13) that winds the spun yarn.

Drawing