EP3461771A1

EP3461771A1 - Fiber guide

Info

Publication number: EP3461771A1
Application number: EP17820154.7A
Authority: EP
Inventors: Mami IIDA; Hidehiro TAKENOSHITA; Satoshi Toyoda; Mizuho OOTA; Shuichi Iida
Original assignee: Kyocera Corp
Current assignee: Kyocera Corp
Priority date: 2016-06-28
Filing date: 2017-06-27
Publication date: 2019-04-03
Anticipated expiration: 2037-06-27
Also published as: CN109689550B; EP3461771A4; WO2018003800A1; JP6708736B2; JPWO2018003800A1; CN109689550A; EP3461771B1

Abstract

The contact surface of a fiber guide (10) according to the present disclosure contacting a fiber (1) has a 20% cut level load length ratio Rmr20, as calculated from a roughness curve, of 15% or lower, and a 50% cut level load length ratio Rmr50, as calculated from a roughness curve, of 60% or higher.

Description

Technical Field

The present disclosure pertains to a fiber guide.

Background Art

Fiber guides of various forms, such as roller guides, oiling nozzles, rod guides, and traverse guides, are attached to fiber machines to guide the fibers. It is required that the surface of a fiber guide that contacts the fibers (hereafter referred to as the contact surface) does not readily cause damage, such as tearing or fraying, to the fibers.
For example, Patent Document 1 proposes a fiber guide in which the surface roughness Ra of the surface contacting a conveyed fiber bundle is 0.1 µm or less.

Citation List

Patent Literature

Patent Document 1: JP 2000-73225 A

Summary of Invention

The fiber contact surface of the fiber guide of the present disclosure has a 20% cut level load length ratio Rmr20, as calculated from a roughness curve, of 15% or lower, and a 50% cut level load length ratio Rmr50, as calculated from a roughness curve, of 60% or higher.

Brief Description of Drawings

FIG. 1 is a perspective view of a roller guide illustrating one example of the fiber guide of the present disclosure.
FIG. 2 is a perspective view of an oiling nozzle illustrating one example of the fiber guide of the present disclosure.
FIG. 3 is a perspective view of a rod guide illustrating one example of the fiber guide of the present disclosure.
FIG. 4 is a perspective view of a traverse guide illustrating one example of the fiber guide of the present disclosure.
FIG. 5 is an enlarged view schematically illustrating one example of a contact surface of the fiber guide of the present disclosure.
FIG. 6 is a schematic illustration of a sliding testing apparatus.

Description of Embodiment

In recent years, fiber feed rates have reached extremely high speeds of 3000 to 10000 m/min in order to improve fiber production efficiency. The increase in fiber feed rate has increased the incidence of damage to fibers caused by friction with the contact surface. Therefore, there is a demand for a fiber guide having a low contact surface coefficient of friction that will result in little damage to fibers even at increased fiber feed rates.
The contact surface of the fiber guide of the present disclosure has a low coefficient of friction, thereby making it possible to minimize damage to fibers when guiding the fibers. The fiber guide of the present disclosure will now be described in detail with reference to the drawings.
First, representative types of fiber guides will be described with reference to FIGS. 1 to 4. The roller guide 10a illustrated in FIG. 1 guides a fiber 1 in a V-shaped groove portion while rotating. The oiling nozzle 10b illustrated in FIG. 2 is used to apply oil to a sliding fiber 1. The rod guide 10c illustrated in FIG. 3 is used to bundle or separate the fiber 1. The traverse guide 10d illustrated in FIG. 4 is used as a guide when winding the fiber 1 around the outer circumference of a cylindrical package. In the following description, the fiber guide will be labeled with the numeral "10" when not discussing a specific fiber guide.
The contact surface of the fiber guide 10 of the present disclosure contacting the fiber 1 has a 20% cut level load length ratio Rmr20, as calculated from a roughness curve, of 15% or lower, and a 50% cut level load length ratio Rmr50, as calculated from a roughness curve, of 60% or higher.
By virtue of satisfying this property, the contact surface of the fiber guide 10 of the present disclosure has a low coefficient of friction, thereby making it possible to minimize damage to the fiber 1 when guiding the fiber 1. Specifically, because the load length ratio Rmr20 of the contact surface is 15% or lower, there is a low contact surface area between the fiber 1 and the contact surface when the fiber 1 is being guided. Because the load length ratio Rmr50 is 60% or higher, the fiber 1 does not readily dig into the bottom of the trough in the contact surface, enabling the fiber 1 to smoothly slide. As a result, the fiber guide 10 of the present disclosure has a low contact surface coefficient of friction.
The load length ratio Rmr as calculated from a roughness curve is defined in JIS B 0601 (2013), and is the ratio, expressed as a percentage, of a cut length obtained when a reference length in an average line direction is taken from a roughness curve, and the roughness curve of this section is cut at a cut level parallel to a peak line, to the total reference length. Cut level refers to the ratio, expressed as a percentage, of height to maximum height (the sum of maximum peak height and maximum trough depth as indicated in JIS B 0601 (2013)) along the reference length. In other words, the 0% cut level load length ratio Rmr0 is 0%, and the 100% cut level load length ratio Rmr100 is 100%.
The contact surface of the fiber guide 10 of the present disclosure may have a load length ratio Rmr50 of 75% or higher. In a case where this property is satisfied, the fiber 1 will not readily dig into the bottom of the trough in the contact surface, enabling the fiber 1 to smoothly slide.
The contact surface of the fiber guide 10 of the present disclosure may have an average interval Rsm between peaks and troughs, as calculated from a roughness curve, of from 5 µm to 25 µm. In a case where this property is satisfied, it will be possible to minimize skipping of the fiber 1 when guiding the fiber 1, while reducing the contact surface area between the fiber 1 and the contact surface, enabling the fiber 1 to smoothly slide.
The average interval Rsm between peaks and troughs as calculated from a roughness curve is defined in JIS B 0601 (2013), and, defining the sum of the lengths of center lines corresponding to one peak and one trough adjacent thereto as the interval between the peak and the trough, is an indicator of the average value of this interval.
The contact surface of the fiber guide 10 of the present disclosure may have a peak count Pc, as calculated from a roughness curve, of 10 to 30. In a case where this property is satisfied, it will be possible to further minimize skipping of the fiber 1 when guiding the fiber 1, while further reducing the contact surface area between the fiber 1 and the contact surface, enabling the fiber 1 to smoothly slide.
The peak count Pc as calculated from a roughness curve is defined in JIS B 0601 (2013), and, defining average roughness height as a center line, is an indicator of the number of sections forming peaks and troughs present per unit of length (10 mm) with respect to the center line.
The load length ratio Rmr20, load length ratio Rmr50, average interval Rsm between peaks and troughs, and peak count Pc of the contact surface may be obtained by measuring the contact surface with a surface roughness gauge (e.g., a successor model of the SE-3300, such as the SE-3400, SE-3500, or SE-S500K, available from Kosaka Laboratory Ltd.) according to JIS B 0601 (2013), and calculating. Measurement conditions may be a reference length of 0.8 mm, a cutoff value of 1 mm, a stylus tip radius of 2 µm, and a stylus tip speed of 0.5 mm/sec. The contact surface may be obatined by calculating an average value of measurements meaured at at least five locations.
There is no particular limitation upon the material used for the contact surface of the fiber guide 10 of the present disclosure. In a case where the contact surface is made of ceramic, it will be possible to minimize damage to the fiber 1 due to the superior wear resistance and heat resistance of ceramic compared to metal or resin.
Among ceramics, aluminum oxide-based ceramic in particular is an inexpensive material; thus, forming the contact surface from aluminum oxide-based ceramic will make it possible to minimize costs.
A contact surface made of aluminum oxide-based ceramic may be manufactured by coating the surface of a member made of metal, resin, etc., with aluminum oxide-based ceramic; however, manufacturing the fiber guide 10 itself from aluminum oxide-based ceramic will yield better durability. As used herein, aluminum oxide-based ceramic refers to ceramics in which at least 80 mass% of the total 100 mass% of all components making up the ceramic is constituted by aluminum oxide.
The material used for the contact surface may be confirmed according to the following method. First, the contact surface is measured using an X-ray diffractometer (XRD), and identification based on the value for 2θ (wherein 2θ is diffraction angle) thus obtained is performed using a JCPDS card. Next, an X-ray fluorescence analyzer (XRF) is used to quantitatively analyze the constituent components. In a case where, for example, the abovementioned identification confirms the presence of aluminum oxide, and the aluminum oxide (Al₂O₃) content as calculated from the Al content measured by the XRF is at least 80 mass%, the ceramic is an aluminum-oxide-based ceramic.
In a case where the contact surface of the fiber guide 10 of the present disclosure is made of an aluminum oxide-based ceramic, the average roundness of the crystal particles 2 of the aluminum oxide may be from 0.55 to 0.8, as illustrated in FIG. 5. In a case where this property is satisfied, the gaps between the crystal particles 2 of the aluminum oxide will decrease while shedding of the crystal particles 2 of the aluminum oxide is minimized, making it possible to further reduce the coefficient of friction of the contact surface. Average roundness is the average value of roundness, and is an indicator of the degree of circularity. Roundness is 1 in the case of a perfect circle, and decreases as circularity of shape is disrupted.
The average roundness of the crystal particles 2 of the aluminum oxide in the contact surface can be calculated according to the following method. First, surface analysis of the contact surface is performed using an electron probe microanalyzer (EPMA). Particles in which titanium is not detected and aluminum and oxygen are simultaneously detected by surface analysis color mapping are considered to be aluminum oxide crystal particles 2. Next, the contact surface is photographed using a scanning electron microscope (SEM). FIG. 5 can be considered as a schematic illustration of the contact surface as observed under an SEM or the like; the aluminum oxide crystal particles 2 exhibit a whitish color. The aluminum oxide crystal particles 2 are copied from this photograph of the contact surface to tracing paper. The tracing paper can then be scanned as image data, and subjected to image analysis using the image analysis software Azo-kun (trade name, Asahi Kasei Engineering Cooperation; subsequent references to the image analysis software "Azo-kun" indicate the image analysis software produced by Asahi Kasei Engineering Cooperation) using a technique called particle analysis, to calculate average roundness of the aluminum oxide crystal particles 2. The analysis conditions for the image analysis software Azo-kun may be "light" for crystal particle lightness, "automatic" for binarization method, and "present" for shading. In a case where, during the course of the abovementioned measurement, it is difficult to photograph the contact surface using an SEM due to the curvature of the contact surface, the contact surface may be ground to a flat surface, and this ground surface considered identical to the contact surface for purposes of measurement.
In addition, the contact surface of the fiber guide 10 of the present disclosure may include aluminum titanate crystal particles 3, as illustrated in FIG. 5. Aluminum titanate is a material expressed by the compositional formula Al₂TiO₅, and has an extremely low Young's modulus compared to aluminum oxide. Specifically, the Young's modulus of aluminum titanate is about 4 to 6 GPa, whereas the Young's modulus of aluminum oxide is about 150 to 400 GPa. Therefore, in a case where this property is satisfied, the aluminum titanate crystal particles 3 that contact the fiber 1 when the fiber 1 is being guided will elastically deform, enabling damage to the fiber to be minimized.
The presence or absence of aluminum titanate crystal particles 3 on the contact surface can be confirmed using the following method. First, surface analysis of the contact surface is performed using an EPMA. Particles in which titanium, aluminum, and oxygen are simultaneously detected by surface analysis color mapping may be considered to be aluminum titanate crystal particles 3. As opposed to the aluminum oxide crystal particles 2, which exhibit a whitish color as illustrated in FIG. 5, the aluminum titanate crystal particles 3 exhibit a blackish color, and thus are visually distinguishable.
The average crystal particle size of the aluminum titanate crystal particles 3 on the contact surface of the fiber guide 10 of the present disclosure may be from 2 µm to 10 µm, and the ratio of the area occupied by the aluminum titanate crystal particles 3 may be from 1 area% to 7 area%. In a case where this property is satisfied, a structure will be yielded that, even if the temperature of the contact surface increases as the result of the fiber 1 being guided over an extended period of time, is resistant to crack formation caused by the difference in thermal expansion coefficient between aluminum titanate and aluminum oxide. As a result, a low coefficient of friction can be maintained for the contact surface of the fiber guide 10 of the present disclosure, thereby making it possible to minimize damage to the fiber 1.
The average crystal particle size of the aluminum titanate crystal particles 3 and the ratio of the area occupied by the aluminum titanate crystal particles 3 on the contact surface can be calculated according to the following method.
First, the contact surface is photographed using an SEM. Next, taking advantage of the fact that the crystal particles 3 of aluminum titanate exhibit a blackish color as described above, the photograph is used to perform image analysis using the image analysis software Azo-kun using a technique called particle analysis. It is thus possible to calculate the average crystal particle size of the aluminum titanate crystal particles 3 and the ratio of the area occupied by the aluminum titanate crystal particles 3. The analysis conditions for the image analysis software Azo-kun may be "light" for crystal particle lightness, "automatic" for binarization method, and "present" for shading.
Next, a method of measuring the coefficient of friction of the contact surface will be described using FIG. 6. The sliding testing apparatus illustrated in FIG. 6 includes a roller R1, a roller R2, a fiber guide 10, a roller R3, and a roller R4, and is capable of guiding the fiber 1 in that order. A tension detector (not shown in the drawings) is connected to the roller R2 and the roller R3.
A fiber 1 is guided using the sliding testing apparatus, and the measurement value for tension T1 detected by the tension detector of roller R2 and the measurement value for tension T2 detected by the tension detector of roller R3 can be used to calculate the coefficient of friction (µ) using the formula of Amonton's law (µ = {1n(T2-T1)}/θ).
The coefficient of friction varies according to test conditions such as the type of fiber 1 used, the form of the fiber 1, the running speed of the fiber 1, the tension of the fiber 1, and θ. Therefore, identical test conditions need to be used when comparing coefficients of friction.
Next, an example of a method of manufacturing the fiber guide of the present disclosure will be described. Here, an example in which the fiber guide is an oiling nozzle will be described.
First, powdered aluminum oxide (Al₂O₃) constituting a primary feedstock material is placed into a mill along with a solvent and balls, pulverized to a specific particle size, and used to prepare a slurry.
Next, a binder is added to the obtained slurry, after which the slurry is spray dried using a spray dryer to produce granules.
Next, the granules, a thermoplastic resin, and wax or the like are introduced into a kneader, and kneaded while being heated to obtain a green body. The obtained green body is then introduced into a pelletizer to obtain pellets for use as a feedstock material for injection molding. Next, the obtained pellets are introduced into an injection molding machine and injection molded to obtain an oiling-nozzle-shaped cast.
In order to obtain an oiling-nozzle-shaped cast in this way, a mold that will yield an oiling nozzle shape may be manufactured according to a typical injection molding method, and the mold installed in an injection molding machine to perform injection molding. The surface texture of the inner face of the mold will be transferred to the surface of the cast; thus, in order to obtain a contact surface having a load length ratio Rmr20 of 15% or less and a load length ratio Rmr50 of 60% or higher, a mold having an inner face with a corresponding surface texture may be used to produce the cast. The same holds true when seeking to obtain a contact surface having a load length ratio Rmr50 of 75% or higher, an average interval Rsm between peaks and troughs of from 5 µm to 25 µm, and a peak count Pc of from 10 to 30.
Next, in a case where, for example, aluminum oxide is the primary feedstock material, the oiling-nozzle-shaped cast is fired in an air atmosphere at a maximum temperature of 1500°C to 1600°C, with a maximum temperature retention time of 2 to 5 hours, to obtain an oiling-nozzle-shaped sintered compact. Firing conditions such as maximum temperature and retention time will vary according to the shape and size of the final product, and thus may be adjusted as necessary. Finally, the compact is washed and dried to obtain the oiling nozzle of the present disclosure.
To obtain a contact surface in which the average roundness of the aluminum oxide crystal particles is from 0.55 to 0.8, the standard deviation of the particle size of the powdered aluminum oxide after being pulverized in the mill may be from 0.05 µm to 0.2 µm. The particle size of the powdered aluminum oxide is a value measured via laser diffraction.
In order to obtain a contact surface in which aluminum titanate crystal particles are present, powdered aluminum titanate (Al₂TiO₅) may be added to the powdered aluminum oxide constituting the primary feedstock material. By imparting the powdered aluminum titanate with an average particle size from 0.5 µm to 1.2 µm, and adjusting the proportions of powdered aluminum oxide and powdered aluminum titanate so that the Al content is from 87 to 96 mass% in the form of Al₂O₃ and from 4 to 13 mass% in the form of Al₂TiO₅, it is possible to obtain a contact surface in which the average particle size of the aluminum titanate crystal particles is from 2 µm to 10 µm, and the ratio of the area occupied by aluminum titanate crystal particles is from 1 area% to 7 area%. The average particle size of the powdered aluminum titanate is a value measured via laser diffraction.

Example 1

First, 99.6% purity powdered aluminum oxide constituting a feedstock powder was introduced into a mill along with water as a solvent and balls, and pulverized to prepare a slurry.
Next, a binder was added to the slurry, after which the slurry was spray dried using a spray dryer to produce granules. A thermoplastic resin and wax or the like were then added to the obtained granules, introduced into a kneader, and kneaded while being heated to obtain a green body. Next, the obtained green body was introduced into a pelletizer to obtain pellets for use as a feedstock material for injection molding. The pellets were then introduced into an injection molding machine to obtain an oiling-nozzle-shaped cast.
The inner faces of the molds installed in the injection molding machine were imparted with a surface texture yielding the load length ratios Rmr20 and load length ratios Rmr50 listed in Table 1.
Next, the oiling-nozzle-shaped casts were fired in an air atmosphere at a maximum temperature of 1550°C, with a maximum temperature retention time of 3 hours, to obtain oiling-nozzle-shaped sintered compacts. Finally, the compacts were washed and dried to obtain samples.
Next, the load length ratios Rmr20 and the load length ratios Rmr50 of the contact surfaces of the samples were calculated by measuring the contact surfaces according to JIS B 0601 (2013) using a surface roughness gauge (SE-3500 available from Kosaka Laboratory Ltd.). Measurement conditions were a reference length of 0.8 mm, a cutoff value of 1 mm, a stylus tip radius of 2 µm, and a stylus tip speed of 0.5 mm/sec. The contact surface was measured at five locations, and an average value was calculated.
Next, the samples were set in the sliding testing apparatus illustrated in FIG. 6 and subject to sliding testing to determine the coefficients of friction of the samples. Measurement conditions were as follows.
Fiber type: nylon (75 den)
Fiber running speed: 1000 m/min
θ: 90°
Fiber tension: 50 gf
Measurement frequency: 10 times (per min)
Coefficient of friction: The coefficient of friction was calculated from the detected tension, with the average of 10 values being taken as the coefficient of friction.

Results are shown in Table 1.

[Table 1]

Sample No.	Load length ratio		Coefficient of friction
Sample No.	Rmr20 (%)	Rmr50 (%)	Coefficient of friction
1	17	60	0.33
2	8	57	0.33
3	16	58	0.34
4	15	70	0.31
5	8	69	0.31
6	5	67	0.31
7	5	65	0.31
8	5	63	0.31
9	5	62	0.31
10	3	60	0.31

As shown by the results listed in Table 1, Samples No. 4 to 10 had a low coefficient of friction of 0.31 compared to Samples No. 1 to 3. From these results, it was determined that a fiber guide in which the contact surface has a load length ratio Rmr20 of 15% or lower and a load length ratio Rmr50 of 60% or higher has a low contact surface coefficient of friction, and thus is capable of minimizing damage to fibers when the fibers are guided.

Example 2

Next, multiple oiling nozzles having different values for the load length ratio Rmr50 of the contact surface were manufactured. These oiling nozzles were subjected to sliding testing, and the coefficients of friction of the contact surfaces were compared. The manufacturing method was the same as the manufacturing method used for Sample No. 7 in Example 1, except that the surface texture of the inner face of the mold installed in the injection molding machine was altered so as to yield the load length ratios Rmr50 listed in Table 2. Sample No. 11 is the same sample as Sample No. 7 in Example 1.
Next, the load length ratios Rmr50 of the contact surfaces of the samples were calculated by measuring according to the same method as in Example 1.
The same sliding testing as in Example 1 was performed to calculate the coefficients of friction of the contact surfaces of the samples. Results are shown in Table 2. [Table 2]

Sample No. Load length ratio Rmr50 (%) Coefficient of friction

11 65 0.31

12 75 0.29

13 82 0.29
As shown by the results listed in Table 2, samples No. 12 and 13 had a low coefficient of friction of 0.29. From these results, it was determined that a fiber guide in which the contact surface has a load length ratio Rmr50 of 75% or higher has a lower contact surface coefficient of friction.

Example 3

Next, multiple oiling nozzles having different values for the average interval Rsm between peaks and troughs on the contact surface were manufactured. These oiling nozzles were subjected to sliding testing, and the coefficients of friction of the contact surfaces were compared. The manufacturing method was the same as the manufacturing method used for Sample No. 7 in Example 1, except that the surface texture of the inner face of the mold installed in the injection molding machine was altered so as to yield the average intervals Rsm between peaks and troughs listed in Table 3. Sample No. 14 is the same sample as Sample No. 7 in Example 1.
Next, the average intervals Rsm between peaks and troughs on the contact surfaces of the samples were calculated by measuring according to the same method as in Example 1.
The same sliding testing as in Example 1 was performed to calculate the coefficients of friction of the contact surfaces of the samples. Results are shown in Table 3. [Table 3]

Sample No. Rsm (µm) Coefficient of friction

14 3 0.31

15 5 0.29

16 12 0.29

17 25 0.29

18 29 0.31
As shown by the results listed in Table 3, Samples No. 15 to 17 had a low coefficient of friction of 0.29. From these results, it was determined that a fiber guide in which the contact surface has an average interval Rsm between peaks and troughs of from 5 µm to 25 µm has a lower contact surface coefficient of friction.

Example 4

Next, multiple oiling nozzles having different values for the peak count Pc of the contact surface were manufactured. These oiling nozzles were subjected to sliding testing, and the coefficients of friction of the contact surfaces were compared. The manufacturing method was the same as the manufacturing method used for sample No. 7 in Example 1, except that the surface texture of the inner face of the mold installed in the injection molding machine was altered so as to yield the peak counts Pc listed in Table 4. Sample No. 19 is the same sample as Sample No. 7 in Example 1.
Next, the peak counts Pc of the contact surfaces of the samples were calculated by measuring according to the same method as in Example 1.
The same sliding testing as in Example 1 was performed to calculate the coefficients of friction of the contact surfaces of the samples. Results are shown in Table 4. [Table 4]

Sample No. Pc Coefficient of friction

19 7 0.31

20 10 0.29

21 21 0.29

22 30 0.29

23 34 0.31
As shown by the results listed in Table 4, Samples No. 20 to 22 had a low coefficient of friction of 0.29. From these results, it was determined that a fiber guide in which the contact surface has a peak count Pc of 10 to 30 has a lower contact surface coefficient of friction.

Example 5

Next, multiple oiling nozzles including contact surfaces that were made of aluminum oxide-based ceramic and had different values for the average roundness of the aluminum oxide crystal particles were manufactured. These oiling nozzles were subjected to sliding testing, and the coefficients of friction of the contact surfaces were compared. The manufacturing method was identical to the manufacturing method of Sample No. 7 in Example 1, except that the standard deviations of the particle size of the powdered aluminum oxide after being pulverized in the mill were the values shown in Table 5.
Next, the average roundness of the aluminum oxide crystal particles in the contact surfaces of the samples were calculated according to the following method. First, surface analysis of the contact surface was performed using an EPMA. Particles in which titanium was not detected and aluminum and oxygen were simultaneously detected by surface analysis color mapping were considered aluminum oxide crystal particles. Next, the contact surface was photographed using an SEM, and the aluminum oxide crystal particles were copied from the photograph to tracing paper. The tracing paper was then scanned in as image data, and subjected to image analysis using the image analysis software Azo-kun using a technique called particle analysis to calculate the average roundness of the aluminum oxide crystal particles. The analysis conditions for the image analysis software Azo-kun were "light" for crystal particle lightness, "automatic" for binarization method, and "present" for shading.
The same sliding testing as in Example 1 was performed to calculate the coefficients of friction of the contact surfaces of the samples. Results are shown in Table 5. [Table 5]

Sample No. Standard deviation (µm) Degree of circularity Coefficient of friction

24 0.24 0.51 0.31

25 0.2 0.55 0.29

26 0.11 0.68 0.29

27 0.05 0.8 0.29

28 0.04 0.86 0.31
As shown by the results listed in Table 5, Samples No. 25 to 27 had a low coefficient of friction of 0.29. From these results, it was determined that a fiber guide in which the average roundness of the aluminum oxide crystal particles is from 0.55 to 0.8 has a lower contact surface coefficient of friction.

Example 6

Next, oiling nozzles in which aluminum titanate crystal particles were present on the contact surface were manufactured. Multiple oiling nozzles having different average crystal particle sizes for the aluminum titanate crystal particles and different ratios for the area occupied by the aluminum titanate crystal particles were manufactured. These oiling nozzles were subjected to sliding testing, and the coefficients of friction of the contact surfaces were compared. The manufacturing method was identical to the manufacturing method of Sample No. 26 in Example 5, except that powdered aluminum titanate having the average particle sizes listed in Table 6 mixed with powdered aluminum oxide in the proportions listed in Table 6 were used as feedstock powders.
Next, the presence or absence of aluminum titanate crystal particles on the contact surfaces of the samples were confirmed using the following method. First, surface analysis of the contact surface was performed using an EPMA. Particles in which titanium, aluminum, and oxygen were simultaneously detected by surface analysis color mapping were considered aluminum titanate crystal particles. As a result, the presence of aluminum titanate crystal particles was confirmed in all of the samples.
Next, the average crystal particle sizes of the aluminum titanate crystal particles and the ratios of the area occupied by the aluminum titanate crystal particles on the contact surfaces of the samples were calculated according to the following method. First, the contact surfaces were photographed using an SEM. Next, taking advantage of the fact that the aluminum titanate crystal particles distinguished in the abovementioned measurement exhibited a blackish color, the photographs were subjected to image analysis using the particle analysis technique of the image analysis software Azo-kun to calculate the average crystal particle sizes of the aluminum titanate crystal particles and the ratios of the area occupied by the aluminum titanate crystal particles. The analysis conditions for the image analysis software Azo-kun were "light" for crystal particle lightness, "automatic" for binarization method, and "present" for shading.
Next, the load length ratios Rmr20, load length ratios Rmr50, average intervals Rsm between peaks and troughs, and peak counts Pc of the contact surfaces of the samples were calculated by measuring according to the same methods as in Example 1. As a result, the load length ratios Rmr20, load length ratios Rmr50, average intervals Rsm between peaks and troughs, and peak counts Pc of the samples had the same values as Sample No. 26 in Example 5.

The same sliding testing as in Example 1 was performed to calculate the coefficients of friction of the contact surfaces of the samples. Results are shown in Table 6.

[Table 6]

Sample No.	Feedstock powder proportions (mass %)		Average particle size of powdered Al₂TiO₅ (µm)	Crystal particles		Coefficient of friction
Sample No.	Powdered Al₂O₃	Powdered Al₂TiO₅	Average particle size of powdered Al₂TiO₅ (µm)	Average crystal particle size (µm)	Area ratio (area%)
29	98.58	1.42	1.08	2.8	0.6	0.28
30	97.79	2.21	1.13	2	1.0	0.27
31	97.79	2.21	0.92	5	1.0	0.27
32	96.49	3.51	1.15	1.5	1.6	0.28
33	92.25	7.75	1.12	2.1	3.6	0.27
34	92.25	7.75	1.02	3.7	3.6	0.27
35	92.25	7.75	0.86	5.9	3.6	0.27
36	92.25	7.75	0.57	9.9	3.6	0.27
37	92.25	7.75	0.52	10.7	3.6	0.28
38	85.63	14.37	1.09	2.3	6.9	0.27
39	85.63	14.37	0.82	6.6	6.9	0.27
40	85.63	14.37	0.64	9	6.9	0.27
41	85.01	14.99	0.92	5.3	7.2	0.28

As shown by the results listed in Table 6, samples No. 29 to 41 had low coefficients of friction of 0.28 compared to sample No. 26 in Example 5. From these results, it was determined that a fiber guide in which aluminum titanate crystal particles are present on the contact surface has a lower contact surface coefficient of friction.
From the fact that Samples No. 30, 31, 33 to 36, and 38 to 40 out of Samples No. 29 to 41 had coefficients of friction of 0.27, it was determined that a fiber guide in which the average crystal particle size of the aluminum titanate crystal particles is from 2 µm to 10 µm and the ratio of the area occupied by the aluminum titanate crystal particles is from 1 area% to 7 area% will have an even lower contact surface coefficient of friction.

Reference Signs List

1 Fiber
2 Aluminum oxide crystal particle
3 Aluminum titanate crystal particle
10a Roller guide
10b Oiling nozzle
10c Rod guide
10d Traverse guide
10 Fiber guide
R1 to R4 Roller

Claims

A fiber guide in which a fiber contact surface has a 20% cut level load length ratio Rmr20, as calculated from a roughness curve, of 15% or lower, and a 50% cut level load length ratio Rmr50, as calculated from a roughness curve, of 60% or higher.
The fiber guide according to claim 1, wherein the Rmr50 of the contact surface is 75% or higher.
The fiber guide according to claim 1 or 2, wherein the contact surface has an average interval Rsm between peaks and troughs, as calculated from a roughness curve, of from 5 µm to 25 µm.
The fiber guide according to any one of claims 1 to 3, wherein the contact surface has a peak count Pc, as calculated from a roughness curve, of from 10 to 30.
The fiber guide according to any one of claims 1 to 4, wherein the contact surface is made of an aluminum oxide-based ceramic, the aluminum oxide having a crystal particle average roundness of from 0.55 to 0.8.
The fiber guide according to claim 5, wherein the contact surface includes aluminum titanate crystal particles.
The fiber guide according to claim 6, wherein the aluminum titanate crystal particles have an average crystal particle size of from 2 µm to 10 µm, and the ratio of the area occupied by the aluminum titanate crystal particles is from 1 area% to 7 area%.