Synthetic resin material and sliding member

Abstract

To provide a synthetic resin material capable of improving flexural modulus and abrasion resistance, and a sliding member or the like using the same.SOLUTION: In the synthetic resin material, a first fibrous filler, a second fibrous filler, a hard filler and a solid lubricant are dispersed in a matrix composed of a thermoplastic resin. A content of the first fibrous filler is in a range of 15 to 35wt%, and a content of the solid lubricant is in a range of 5 to 15wt%. A content x of the hard filler and a content y of the second fibrous filler with respect to the whole of the synthetic resin material satisfy conditions expressed by 1 ≤ x ≤ 49 (1), 1 ≤ y ≤ 49 (2), and x + y ≤ 50 (3).SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a sliding member and a synthetic resin material constituting the sliding member. [Background technology]

[0002] In ultrasonic motors that utilize the vibration of piezoelectric bodies, the sliding members of the rotor are required to have high flexural modulus and wear resistance in order to improve the efficiency and life of the motor. Resin materials are generally used for the sliding members, and in order to improve the flexural modulus, large amounts of inorganic materials such as whiskers are filled in addition to carbon fibers (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 2899090 Summary of the Invention [Problem to be solved by the invention]

[0004] However, when inorganic fibers are exposed to the sliding surface, they tend to wear out and shorten the life of the motor.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a synthetic resin material that can improve the flexural modulus and wear resistance, and a sliding member or the like that uses the same. [Means for solving the problem]

[0006] The synthetic resin material of the present invention comprises: A synthetic resin material in which a first fibrous filler, a second fibrous filler, a non-fibrous hard filler, and a solid lubricant are dispersed in a matrix made of a thermoplastic resin, the content of the first fibrous filler is in the range of 15 to 35 wt % and the content of the solid lubricant is in the range of 5 to 15 wt % relative to the entire synthetic resin material; The content x of the hard filler and the content y of the second fibrous filler relative to the total synthetic resin material satisfy the conditions expressed by 1 wt%≦x≦49 wt% (1), 1 wt%≦y≦49 wt% (2), and x+y≦50 wt% (3).

[0007] According to the synthetic resin material of this configuration or a sliding member in which at least the surface layer portion of the sliding portion is made of this synthetic resin material, the flexural modulus and wear resistance are improved. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is an explanatory diagram relating to the configuration of an ultrasonic motor in which a sliding member according to one embodiment of the present invention is used; [Figure 2] FIG. 2 is an explanatory diagram showing the contents of the hard filler and the second fibrous filler in each sample. [Figure 3] FIG. 1 is an explanatory diagram showing the increase rate of the flexural modulus of each sample. [Figure 4] FIG. 1 is an explanatory diagram showing the reduction rate of the amount of wear of each sample. [Figure 5] FIG. 1 is an explanatory diagram of a first specimen region in an SEM photograph of a sample. [Figure 6] FIG. 1 is an explanatory diagram of a second specimen region in an SEM photograph of a sample. [Figure 7] FIG. 1 is an explanatory diagram regarding the flexural modulus of samples having different shapes of added hard fillers. [Figure 8] FIG. 1 is an explanatory diagram regarding the abrasion resistance of samples having different shapes of added hard fillers. DETAILED DESCRIPTION OF THE INVENTION

[0009] A sliding member according to one embodiment of the present invention is used, for example, as a component of an ultrasonic motor 1 shown in Fig. 1. As shown in Fig. 1, the ultrasonic motor 1 includes an output shaft 10, a rotor 11, a stator 12, and a piezoelectric element 14. An annular sliding member 112 is provided on the rotor 11 so as to extend in a substantially annular shape along its outer periphery. The rotor 11 is pressed against the stator 12 via the sliding member 112 by the biasing force of an elastic member (not shown). When a drive signal is applied to the piezoelectric element 14, a traveling wave is generated in the stator 12 in the circumferential direction, and the traveling wave rotates the rotor 11 and the output shaft attached concentrically to the rotor 11.

[0010] In addition to constituting at least a part of the rotor 11 of the ultrasonic motor 1, the sliding member 112 may also constitute at least a part of a component and / or part that requires sliding properties with a mating member, such as a slide plate, liner, guide, star wheel, bearing, bushing, roller, etc.

[0011] At least the surface layer of the sliding portion (the portion that is pressed against the stator 12) of the sliding member 112 is made of the synthetic resin material of the present invention. In the synthetic resin material, a first fibrous filler, a second fibrous filler, a hard filler, and a solid lubricant are dispersed in a matrix made of a thermoplastic resin.

[0012] Examples of "thermoplastic resins" that can be used include super engineering plastics such as PPS resin, PES resin, PEK resin, PEI resin, PI resin, PAI resin, PEEK resin, and PSU resin, as well as general-purpose engineering plastics such as POM resin, PA resin, PET resin, PC resin, and liquid crystal polymer, or combinations of these. The content of the thermoplastic resin in the synthetic resin material is, for example, in the range of 30 to 78 wt%, 30 to 47 wt%, or 30 to 43 wt%.

[0013] The "first fibrous filler" may be at least one of carbon fiber (e.g., PAN-based carbon fiber or pitch-based carbon fiber), glass fiber (e.g., E-glass fiber, C-glass fiber), and aramid fiber. The fiber length of the first fibrous filler in the synthetic resin material (not the raw material) is, for example, in the range of 5 to 500 μm. The fiber diameter of the first fibrous filler is, for example, in the range of 5 to 10 μm. The content of the first fibrous filler in the synthetic resin material is, for example, in the range of 15 to 35 wt% or 20 to 30 wt%.

[0014] As the "second fibrous filler", whiskers of at least one of calcium carbonate, zinc oxide, rock wool, and potassium titanate are used, for example. The fiber length of the second fibrous filler in the synthetic resin material (not the raw material) is, for example, within the range of 1 to 10 μm. The fiber diameter of the second fibrous filler is, for example, within the range of 0.5 to 1 μm. The second fibrous filler may or may not be surface-treated.

[0015] Examples of "hard fillers" include xonotlite (6CaO·6SiO2·H2O), magnesium oxide, phenolic resin, and tobermorite (Ca5·(SiO 18 Non-fibrous particles of at least one of potassium titanate (H2·4H2O) are used. The particle size of the hard filler in the synthetic resin material (not the raw material) is, for example, in the range of 1 to 20 μm, 1 to 15 μm, or 1 to 10 μm.

[0016] The "solid lubricant" used may be, for example, particles of at least one of polytetrafluoroethylene, graphite, graphene, molybdenum disulfide, high-density polyethylene, metal sulfide, and silicone resin. The particle size of the solid lubricant in the synthetic resin material (not the raw material) is, for example, in the range of 5 to 50 μm or 5 to 20 μm. The content of the solid lubricant in the synthetic resin material is, for example, in the range of 5 to 15 wt% or 10 to 15 wt%.

[0017] FIG. 2 shows the relationship between the content x of the hard filler and the content y of the second fibrous filler relative to the total synthetic resin material.

[0018] The content x of the hard filler and the content y of the second fibrous filler relative to the total synthetic resin material satisfy the conditions expressed by the relational expressions (1), (2), and (3). This condition means that (x, y) are included in the right-angled triangular area A0 shown by the solid line in Figure 2.

[0019] 1wt%≦x≦49wt% ‥(1).

[0020] 1wt%≦y≦49wt% ‥(2).

[0021] x+y≦50wt% ‥(3).

[0022] It is preferable that the content x of the hard filler and the content y of the second fibrous filler relative to the total synthetic resin material satisfy the conditions expressed by the relational expressions (11) and (21). This condition means that (x, y) are included in the rectangular first designated area A1 shown by the dashed line in Figure 2.

[0023] 1wt%≦x≦13wt% ‥(11).

[0024] 5wt%≦y≦20wt% ‥(21).

[0025] It is more preferable that the content x of the hard filler and the content y of the second fibrous filler relative to the total synthetic resin material satisfy the conditions expressed by the relational expressions (12) and (22), which mean that (x, y) are included in the rectangular second designated area A2 indicated by the two-dot chain line in Figure 2.

[0026] 3wt%≦x≦9wt% ‥(12).

[0027] 5wt%≦y≦18wt% ‥(22).

[0028] (sample) PPS resin as a thermoplastic resin, carbon fiber as a first fibrous filler, surface-treated calcium carbonate whiskers as a second fibrous filler, xonotlite particles as a hard filler, and PTFE particles as a solid lubricant were kneaded together, molded, and then cooled to produce pellets made of synthetic resin material as samples 1 to 20 and samples 56 to 59, and each sample was molded to be the same or approximately the same size. The fiber length and fiber diameter of the first and second fibrous fillers, the particle size of the hard filler and the solid lubricant, and the kneading conditions, such as the kneading time, were adjusted so that the carbon fiber serving as the first fibrous filler in each sample had a fiber length in the range of 5 to 500 μm and a fiber diameter in the range of 5 to 10 μm, the surface-treated calcium carbonate whiskers serving as the second fibrous filler had a fiber length in the range of 1 to 10 μm and a fiber diameter in the range of 0.5 to 1 μm, the xonotlite particles serving as the hard filler had a particle size in the range of 1 to 20 μm, and the PTFE particles serving as the solid lubricant had a particle size in the range of 5 to 50 μm. However, for samples 51 to 55, the amount of PPS resin added was less than 30 wt%, making it difficult to prepare pellets suitable for testing the flexural modulus and abrasion resistance.

[0029] Samples 4(1) to 4(3) were fabricated under the same conditions as Sample 4, except that PEI resin, PEEK resin, and PA resin were used instead of PPS resin as the thermoplastic resin. Samples 4(4) to 4(5) were fabricated under the same conditions as Sample 4, except that glass fiber and aramid fiber were used instead of carbon fiber as the first fibrous filler. Samples 4(6) to 4(8) were fabricated under the same conditions as Sample 4, except that zinc oxide, rock wool, and potassium titanate (KO·nTiO) whiskers were used instead of calcium carbonate (CaCO) whiskers as the second fibrous filler. Samples 4(9) to 4(12) were fabricated under the same conditions as Sample 4, except that magnesium oxide (MgO), phenolic resin, tobermorite, and potassium titanate (KO·nTiO) were used instead of xonotlite as the hard filler. Samples 4(13) to 4(15) were prepared under the same conditions as Sample 4, except that molybdenum dioxide (MoS2), high-density PE, and silicone resin were used instead of PTFE as solid lubricants.

[0030] The contents of the matrix such as PPS resin, the first fibrous filler such as carbon fiber, the second fibrous filler such as surface-treated calcium carbonate whiskers, the hard filler such as xonotlite particles, and the solid lubricant such as PTFE particles for each of Samples 1 to 20 and Samples 4(1) to 4(15) are summarized in Table 1. The contents of the PPS resin, carbon fiber, surface-treated calcium carbonate whiskers, xonotlite particles, and PTFE particles for each of Samples 51 to 59 are summarized in Table 2.

[0031] TIFF2026002100000002.tif234161

[0032] TIFF2026002100000003.tif72161

[0033] (Evaluation of each sample) The rate of increase in the flexural modulus of each sample was measured based on x = 0 wt%. The flexural modulus and its rate of increase were measured for each sample according to the measurement method in accordance with JIS K7171 (or K7017).

[0034] The abrasion reduction rate of each sample was measured based on x = 0 wt%. The abrasion reduction rate and the abrasion reduction rate of each sample were measured according to the measurement method in accordance with JIS K7218.

[0035] SEM images were taken for each of Samples 1, 4, 8, 10, 13, 15, and 16. As shown in Figures 5 and 6, the SEM image of Sample 4 (x=5) shows that the addition of xonotlite (hard filler) to PTFE (synthetic resin material) results in surface-treated calcium carbonate whiskers (second fibrous filler) being evenly dispersed.

[0036] The SEM images were analyzed to measure the sample variance of the number of centroids of the second fibrous filler (surface-treated calcium carbonate whiskers) contained in each of multiple (e.g., 4 to 10) 20 μm × 20 μm first sample regions that did not contain the first fibrous filler, as shown in Figure 5. The SEM images were analyzed to measure the sample variance of the number of centroids of the second fibrous filler (surface-treated calcium carbonate whiskers) contained in each of multiple (e.g., 4 to 10) 40 μm × 60 μm second sample regions that contained the first fibrous filler, as shown in Figure 6. Similar measurements were also made for Samples 104, 108, 113, 115, and 116, which had 0 wt% hard filler (xonotlite) and had an increased content of thermoplastic resin (e.g., PPS resin) constituting the matrix.

[0037] Table 3 shows the measurement results of the rate of increase in flexural modulus and the rate of reduction in wear volume for each of samples 1 to 20 and samples 4(1) to 4(15). Table 3 also shows the measurement results of the sample variance of the number of centroids for each of samples 1, 4, 8, 10, 13, 15, and 16. Table 4 shows the measurement results of the rate of increase in flexural modulus and the rate of reduction in wear volume for each of samples 56, 58, and 59. Table 4 also shows the measurement results of the sample variance of the number of centroids for each of samples 104, 108, 113, 115, and 116.

[0038] TIFF2026002100000004.tif225161

[0039] TIFF2026002100000005.tif78161

[0040] As is clear from Table 3, Figures 2 and 3, for samples 1 to 20 and samples 4(1) to 4(15) included in area A0, the increase in flexural modulus from the case where x = 0 is in the range of 1 to 11%. For samples 1 to 17, 4(1) to 4(8), and 4(13) to 4(15) included in the first designated area A1, the increase in flexural modulus from the case where x = 0 is in the range of 3 to 11%. For samples 1, 2, 4, 5, 7 to 10, 14 to 17, and samples 4(1) to 4(15) included in the second designated area A2, the increase in flexural modulus from the case where x = 0 is in the range of 1 to 9%.

[0041] As is clear from Table 4, for sample 59, in which the content of the solid lubricant was 16 wt%, exceeding the upper limit of the range of 5 to 15 wt%, the increase rate of the flexural modulus was -1%.

[0042] As is clear from Table 3, Figure 2, and Figure 4, for samples 1 to 20 and samples 4(1) to 4(15) included in area A0, the reduction rate of wear volume relative to the case where x = 0 is between 1 and 68%. For samples 1 to 17 and samples 4(1) to 4(15) included in the first designated area A1, the reduction rate of wear volume relative to the case where x = 0 is between 2 and 63%. For samples 1, 2, 4, 5, 7 to 10, 14 to 17, and samples 4(1) to 4(15) included in the second designated area A2, the reduction rate of wear volume relative to the case where x = 0 is between 2 and 63%.

[0043] As is clear from Table 4, the wear reduction rate was -1% for Sample 56, in which the content of the first fibrous filler was 14 wt%, which is below the lower limit of the range of 15 to 35 wt%, and the wear reduction rate was -1% for Sample 56, in which the content of the solid lubricant was 4 wt%, which is below the lower limit of the range of 5 to 15 wt%.

[0044] As is clear from Table 3, for samples 1, 4, 8, 10, 13, 15, and 16 included in the first designated area A1, the sample variance of the number of whisker centroids in the first sample area is included in 38 to 595, and the sample variance of the number of whisker centroids in the second sample area is included in 370 to 5452. For samples 1, 4, 8, 10, 15, and 16 included in the second designated area A2, the sample variance of the number of whisker centroids in the first sample area is included in 38 to 595, and the sample variance of the number of whisker centroids in the second sample area is included in 370 to 2314.

[0045] (Another embodiment of the present invention) Similar to sample 4, a sample containing irregularly shaped (irregularly shaped) xonotlite particles, a sample containing spherical (approximately spherical) xonotlite particles, and a sample without any xonotlite particles were prepared. Figure 7 shows the results of measuring the flexural modulus of each of the three samples. Figure 7 indicates that there is little difference in the rate of increase in the flexural modulus of the samples between irregularly shaped and spherical xonotlite particles. Figure 8 shows the results of measuring the wear volume of each of the three samples. Figure 8 indicates that the sample containing spherical xonotlite particles exhibited a higher reduction in wear volume than the sample containing irregularly shaped xonotlite particles. [Explanation of symbols]

[0046] 1. Ultrasonic motor 10. Output shaft 11. Rotor 12. Stator 14. Piezoelectric element 112. Sliding member

Claims

1. A synthetic resin material comprising a matrix made of a thermoplastic resin, and a first fibrous filler, a second fibrous filler, a non-fibrous hard filler, and a solid lubricant dispersed therein, the content of the first fibrous filler is in the range of 15 to 35 wt % and the content of the solid lubricant is in the range of 5 to 15 wt % relative to the entire synthetic resin material; The content x of the hard filler and the content y of the second fibrous filler relative to the total synthetic resin material satisfy the conditions expressed by 1 wt%≦x≦49 wt% (1), 1 wt%≦y≦49 wt% (2), and x+y≦50 wt% (3). Synthetic resin material.

2. The synthetic resin material according to claim 1, Satisfy the conditions expressed by 1 wt%≦x≦13 wt% (11) and 5 wt%≦y≦20 wt% (21). Synthetic resin material.

3. The synthetic resin material according to claim 2, Satisfy the conditions expressed by 3 wt%≦x≦9 wt% (12) and 5 wt%≦y≦18 wt% (22). Synthetic resin material.

4. The synthetic resin material according to claim 1, With respect to the case where x=0 wt%, the increase rate of the flexural modulus of the synthetic resin material is within the range of 1 to 11%, and the reduction rate of the wear amount of the synthetic resin material is within the range of 1 to 63%. Synthetic resin material.

5. The synthetic resin material according to claim 1, The first fibrous filler includes at least one of carbon fiber, glass fiber, and aramid fiber; the second fibrous filler includes whiskers of at least one of calcium carbonate, zinc oxide, rock wool, and potassium titanate; The hard filler contains particles of at least one of xonotlite, magnesium oxide, phenolic resin, tobermorite, and potassium titanate, The solid lubricant contains particles of at least one of polytetrafluoroethylene, graphite, graphene, molybdenum disulfide, high-density polyethylene, metal sulfide, and silicone resin. Synthetic resin material.

6. The synthetic resin material according to claim 1, The second fibrous filler has a fiber length in the range of 1 to 10 μm and a fiber diameter in the range of 0.5 to 1 μm, The particle size of the hard filler is in the range of 1 to 20 μm. Synthetic resin material.

7. The synthetic resin material according to claim 5, The sample variance of the number of centroids of the second fibrous filler contained in each of a plurality of 20 μm×20 μm first sample areas on the surface of the synthetic resin material that do not contain the first fibrous filler is in the range of 38 to 595. Synthetic resin material.

8. The synthetic resin material according to claim 5, The sample variance of the number of centroids of the second fibrous filler included in each of a plurality of second sample areas of 40 μm×60 μm in which the first fibrous filler is included on the surface of the synthetic resin material is in the range of 370 to 2314. Synthetic resin material.

9. At least the surface layer of the sliding portion is made of the synthetic resin material according to any one of claims 1 to 8. Sliding member.

10. A sliding member used in a rotor of an ultrasonic motor, the sliding member being made of the sliding member according to claim 9.

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