Grease composition and control cable

Abstract

This invention provides a grease composition that, when applied to the outer surface of an inner cable or the like, can improve the overall performance of wear resistance and stick-slip resistance. [Solution] A grease composition comprising a base oil, a modified silicone, a thickener, and a solid lubricant, wherein the solid lubricant comprises two or more melamine cyanurates with different volume average particle sizes.

Description

[Technical Field]

[0001] This invention relates to a grease composition and a control cable. [Background technology]

[0002] A control cable transmits force or movement from a user's hand to a location far away from the user. It consists of an inner cable slidably inserted into an outer casing. For example, when transmitting the movement of a car's gear shift lever to the transmission via a control cable, when the user operates the gear shift lever, the inner cable is pushed and pulled, thereby transmitting the user's operating force to the transmission.

[0003] In such control cables, grease is often applied to the outer surface of the inner cable. This reduces the resistance (sliding resistance) that occurs when the inner cable slides against the inner surface of the outer casing, thereby preventing a decrease in load efficiency.

[0004] Patent Document 1 describes a grease composition containing a silicone base oil, a thickener, a layered compound powder, and polytetrafluoroethylene powder, which can prevent a decrease in the load efficiency of a control cable. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2012-255094 [Overview of the project] [Problems that the invention aims to solve]

[0006] The polytetrafluoroethylene used in Patent Document 1 has high stability, and there are concerns about its impact on the natural environment and the human body. It is expected that its use will be restricted by environmental regulations. Therefore, alternative materials for polytetrafluoroethylene are being considered, and it is necessary to study formulations to compensate for the performance degradation associated with reducing or eliminating the use of polytetrafluoroethylene.

[0007] An object of the present invention is to provide a grease composition that can improve the overall performance of wear resistance and anti-stick-slip by applying it to the outer peripheral surface of an inner cable or the like.

Means for Solving the Problems

[0008] The present inventors have found that a grease composition containing a base oil, a modified silicone, a thickener, and two or more kinds of melamine cyanurates having different volume average particle diameters can solve the above problems, and have completed the present invention.

[0009] That is, the present invention provides 〔1〕A grease composition containing a base oil, a modified silicone, a thickener, and a solid lubricant, wherein the solid lubricant contains two or more kinds of melamine cyanurates having different volume average particle diameters. 〔2〕The grease composition according to the above 〔1〕, wherein the solid lubricant contains melamine cyanurate (MCA1) having a volume average particle diameter of 6.0 μm or less and melamine cyanurate (MCA2) having a volume average particle diameter of 10 to 30 μm, and the mass content ratio of MCA1 and MCA2 in the solid lubricant is 60:40 to 99.9:0.1. 〔3〕The grease composition according to the above 〔1〕 or 〔2〕, wherein the total content of melamine cyanurate in the grease composition is 1 to 30% by mass. 〔4〕The grease composition according to any one of the above 〔1〕 to 〔3〕, wherein the base oil contains a silicone base oil, and the content of the silicone base oil in the grease composition is 45% by mass or more and 70% by mass or less. 〔5〕The modified silicone is represented by the following general formula (1), (2), or (3): TIFF2026079372000002.tif80113[wherein, R 1 and R 2 each independently represents -W 1 -COOH, or -W 1 -NH2; when there are a plurality of Rs 3 each independently represents -W 1 -COOH, -W 1 -NH2, or -W 1 -NH-W 2 -NH2; R represents a linear or branched alkyl group having 1 to 30 carbon atoms; R 4 represents -W 1 -COOH; W 1 and W 2 each independently represents a linear or branched alkylene group having 1 to 30 carbon atoms when there are a plurality of them; m and n each independently represent a repetition number of 1 or more], and is one or more modified silicones selected from the group consisting of compounds represented by the above formula, the grease composition according to any one of the above [1] to [4]], 〔6〕The grease composition according to any one of the above [1] to [5]], wherein the content of the modified silicone in the grease composition is 0.01 to 10% by mass. 〔7〕A control cable in which the grease composition according to any one of the above [1] to [6] is applied to the outer peripheral surface of an inner cable.

Advantages of the Invention

[0010] According to the present invention, there is provided a grease composition capable of improving the overall performance of wear resistance and anti-stick-slip by applying it to the outer peripheral surface of an inner cable or the like.

Brief Description of the Drawings

[0011] [Figure 1] It is a cross-sectional view of a control cable according to an embodiment of the present invention. [Figure 2] It is a cross-sectional view showing another embodiment of the control cable. [Figure 3]This is a schematic plan view of the equipment used for durability testing. [Modes for carrying out the invention]

[0012] A method for manufacturing a control cable, including a method for manufacturing a grease composition according to this embodiment, will be described in detail below. However, the following description is illustrative for explaining this embodiment and is not intended to limit the technical scope of the present invention to this scope only. In this specification, when a numerical range is indicated using "~", it includes the numerical values ​​at both ends of that range.

[0013] <Grease composition> The grease composition according to this embodiment contains a base oil, modified silicone, a thickener, and a solid lubricant as essential components. Furthermore, the solid lubricant is characterized by containing two or more types of melamine cyanurates with different volume-average particle sizes. The content of each of the above components contained in the grease composition according to this embodiment can be appropriately selected from the range described so that the total content in the grease composition is 100% by mass or less.

[0014] (Base oil) The base oil is not particularly limited as long as it is a common base oil used in greases, but examples include mineral oil, synthetic hydrocarbon oil, synthetic ester oil, vegetable oil, animal oil, silicone base oil, polyglycol-based synthetic oil, phenyl ether-based synthetic oil, and fluorine-based synthetic oil. Among these, from the viewpoint of lubrication characteristics over a wide temperature range, it is preferable to include a silicone base oil, and a base oil consisting solely of a silicone base oil may also be used. The base oil may be used alone, or two or more may be used in combination.

[0015] Examples of silicone base oils include dimethyl silicone oils such as dimethylpolysiloxane (dimethicone) and highly polymerized methylpolysiloxane; methylphenyl silicone oils such as methylphenylpolysiloxane; cyclic silicone oils such as methylcyclopolysiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, and dodecamethylcyclohexasiloxane; modified silicones such as polyether-modified silicones, carboxy-modified silicones, fatty acid-modified silicones, alcohol-modified silicones, aliphatic alcohol-modified silicones, epoxy-modified silicones, fluorine-modified silicones, and alkyl-modified silicones; and methylhydrogenpolysiloxane and dimethiconol. These silicone base oils may be used individually or in combination of two or more. Note that the modified silicones described later are not included in the silicone base oils.

[0016] The kinematic viscosity of the base oil at 25°C is 50-2000 mm². 2 / s is preferred, and 100~1500mm 2 / s is more preferable, 200~1000mm 2 / s is even more preferable. Kinematic viscosity of 50 mm 2 By setting the kinematic viscosity to 2000 mm² or higher, a sufficient oil film is formed on the outer surface of the inner cable or the inner surface of the outer casing. This suppresses wear on the outer surface of the inner cable or the inner surface of the outer casing, preventing a decrease in load efficiency. On the other hand, if the kinematic viscosity is 2000 mm² or higher... 2 By keeping the kinematic viscosity below / s, the amount of grease composition that penetrates between the outer surface of the inner cable and the inner surface of the outer casing is reduced, preventing an increase in sliding resistance. The kinematic viscosity of the base oil in this specification is measured at 25°C using a glass capillary viscometer in accordance with JIS K 2283:2000.

[0017] The proportion of silicone base oil in the base oil is preferably 50% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 90% by mass or more, even more preferably 95% by mass or more, and particularly preferably 100% by mass.

[0018] From the viewpoint of the effects of the present invention, the content of base oil (preferably silicone base oil) in the grease composition is preferably 35% by mass or more, more preferably 40% by mass or more, even more preferably 45% by mass or more, and particularly preferably 50% by mass or more. Furthermore, the content of base oil (preferably silicone base oil) in the grease composition is preferably 70% by mass or less, more preferably 65% ​​by mass or less, even more preferably 60% by mass or less, even more preferably less than 57% by mass, and particularly preferably 55% by mass or less.

[0019] (Modified silicone) The grease composition according to this embodiment contains a modified silicone as an essential component. By using the melamine cyanurate described below in combination with the modified silicone, it is possible to suppress the decrease in load efficiency of the grease composition and significantly improve its stick-slip resistance. The modified silicone is not particularly limited, but examples include carboxyl-modified silicone, amino-modified silicone, carbinol-modified silicone, polyether-modified silicone, epoxy-modified silicone, etc. These modified silicones may be used individually or in combination of two or more. Among these, from the viewpoint of the effects of the present invention, one or more modified silicones selected from the group consisting of carboxyl-modified silicone and amino-modified silicone are preferred, and carboxyl-modified silicone is more preferred.

[0020] Examples of carboxyl-modified silicones include silicones modified with carboxyl groups at the terminal ends and silicones modified with carboxyl groups in the side chains, with silicones modified with carboxyl groups in the side chains being preferred.

[0021] Examples of amino-modified silicones include silicones modified with amino groups at the terminal ends and silicones modified with amino groups in the side chains, with silicones modified with amino groups in the side chains being preferred.

[0022] Examples of carboxyl-modified silicones and amino-modified silicones include, for example, those of the following general formulas (1), (2), or (3): TIFF2026079372000003.tif80113[where R 1 and R 2 These are, independently, -W 1 -COOH, or -W 1 - Represents NH2; R 3 If there are multiple options, each one can be used independently, -W 1 -COOH, -W 1 -NH2 or -W 1 -NH-W 2 - Represents NH2; R represents a linear or branched alkyl group having 1 to 30 carbon atoms (preferably 2 to 24); R 4 is, -W 1 - Represents COOH; W 1 and W 2 If there are multiple, each independently represents a linear or branched alkylene group having 1 to 30 carbon atoms (preferably 2 to 24); m and n independently represent 1 or more repeating units. One or more modified silicones selected from the group consisting of compounds represented by formula (2) are preferred, and one or more carboxyl-modified silicones (i.e., R) selected from the group consisting of compounds represented by formula (2) are preferred. 3 ga-W 1 -COOH is more preferable.

[0023] The kinematic viscosity at 25°C of a modified silicone (preferably one or more modified silicones selected from the group consisting of carboxyl-modified silicones and amino-modified silicones; more preferably one or more modified silicones selected from the group consisting of compounds represented by the general formulas (1), (2), or (3)) is 100 to 10000 mm². 2 / s is preferred, and 300-7500mm 2 / s is more preferable, 500~5000mm 2 / s is more preferably 700-3000mm 2 / s is particularly preferred.

[0024] From the viewpoint of the effects of the present invention, the content of modified silicone in the grease composition is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, even more preferably 0.5% by mass or more, even more preferably 1.0% by mass or more, and particularly preferably 1.5% by mass or more. On the other hand, from the viewpoint of suppressing the hardening of the grease composition over time, it is preferably 10% by mass or less, more preferably 8.0% by mass or less, even more preferably 6.0% by mass or less, and particularly preferably 4.0% by mass or less.

[0025] (Thickener) The thickener is not particularly limited as long as it is a material commonly used as a thickener for grease. Specific examples of thickeners include metal soap-based thickeners, composite metal soap-based thickeners, and urea compounds, with metal soap-based thickeners being preferred and lithium soap-based thickeners being more preferred. The thickener may be used alone or in combination of two or more types.

[0026] The lithium soap-based thickener (lithium soap) is not particularly limited, but examples include lithium salts of higher fatty acids having 10 to 28 carbon atoms, lithium salts of higher hydroxy fatty acids having 10 to 28 carbon atoms and having one or more hydroxyl groups, or mixtures thereof. Examples of the higher fatty acids include lauric acid, palmitic acid, stearic acid, linoleic acid, arachidic acid, myristic acid, pentadecanoic acid, heptadecanoic acid, oleic acid, arachidonic acid, and behenic acid, but stearic acid is preferred due to its good consistency yield (degree of grease hardening). Examples of the higher hydroxy fatty acids include 12-hydroxystearic acid, 12-hydroxylauric acid, and 16-hydroxypalmitic acid, but 12-hydroxystearic acid is preferred due to its availability and low cost.

[0027] Specific examples of lithium soaps include lithium laurate, lithium stearate, lithium 12-hydroxystearate, and mixtures thereof.

[0028] From the viewpoint of preventing a decrease in load efficiency, the content of the thickener (preferably metal soap, more preferably lithium soap) in the grease composition is preferably 5% by mass or more, more preferably 10% by mass or more, even more preferably 15% by mass or more, even more preferably 20% by mass or more, and particularly preferably 25% by mass or more. On the other hand, from the viewpoint of ensuring the lifespan of the grease composition, it is preferably 45% by mass or less, more preferably 40% by mass or less, and even more preferably 35% by mass or less.

[0029] (Solid lubricant) The grease composition according to this embodiment contains two or more melamine cyanurates with different volume-average particle sizes as a solid lubricant. By using two or more melamine cyanurates with different volume-average particle sizes in combination, it is possible to suppress the decrease in load efficiency of the grease composition and significantly improve its stick-slip resistance.

[0030] The solid lubricant according to this embodiment can, for example, contain melamine cyanurate with a small particle size having a volume-average particle diameter of 8.0 μm or less and melamine cyanurate with a large particle size having a volume-average particle diameter greater than 8.0 μm. Preferably, it contains melamine cyanurate (MCA1) with a volume-average particle diameter of 6.0 μm or less (preferably 0.1 to 6.0 μm, more preferably 1.0 to 6.0 μm) and melamine cyanurate (MCA2) with a volume-average particle diameter of 10 to 30 μm (preferably 10 to 20 μm). Note that the volume-average particle diameter in this specification is a value measured according to the laser diffraction scattering method.

[0031] From the viewpoint of the effects of the present invention, the mass content ratio of small-particle melamine cyanurate to large-particle melamine cyanurate (preferably MCA1 and MCA2) in the solid lubricant is preferably 55:45 to 99.9:0.1, more preferably 60:40 to 99.9:0.1, even more preferably 65:30 to 99:1, even more preferably 70:30 to 98:2, even more preferably 75:25 to 97:3, and particularly preferably 80:20 to 96:4.

[0032] In addition to melamine cyanurate, other solid lubricants that can be used include polytetrafluoroethylene, tungsten disulfide, molybdenum disulfide, graphite, graphite fluoride, mica, boron nitride, and transition metal dichalcogenides.

[0033] From the viewpoint of the effects of the present invention, the total content of the solid lubricant (preferably melamine cyanurate) in the grease composition is preferably 1% by mass or more, more preferably 3% by mass or more, even more preferably 5% by mass or more, and particularly preferably 7% by mass or more. Furthermore, the total content of the solid lubricant (preferably melamine cyanurate) in the grease composition is preferably 30% by mass or less, more preferably 25% by mass or less, even more preferably 20% by mass or less, and particularly preferably 15% by mass or less.

[0034] The proportion of melamine cyanurate (preferably MCA1 and MCA2) in the solid lubricant is preferably 50% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 90% by mass or more, even more preferably 95% by mass or more, and particularly preferably 100% by mass. In other words, a solid lubricant consisting only of melamine cyanurate is also acceptable.

[0035] From the viewpoint of environmental impact, the polytetrafluoroethylene content in the grease composition is preferably less than 4.8% by mass, more preferably less than 3.0% by mass, even more preferably less than 1.0% by mass, even more preferably less than 0.5% by mass, even more preferably less than 0.1% by mass, even more preferably less than 0.01% by mass, and particularly preferably 0% by mass.

[0036] (Other additives) The grease composition according to this embodiment may further contain one or more of the additives listed below. Examples of additives include: metal-based detergents such as alkaline earth metal sulfonates, alkaline earth metal phenates, and alkaline earth metal salicylates; detergent dispersants such as alkenyl succinimide, alkenyl succinimide borylated modified products, benzylamine, and alkyl polyamines; anti-wear agents such as methylene bisdithiocarbamate, polycarboxylate, zinc-based anti-wear agents, sulfur-based anti-wear agents, and phosphorus-based anti-wear agents; thickeners such as polymethacrylate, ethylene-propylene copolymer, styrene-isoprene copolymer, styrene-isoprene copolymer hydride, and polyisobutylene; alkylphenols such as 2,6-di-tert-butyl-p-cresol, and 4,4'-methylenebis-(2,6-di-t- Antioxidants include bisphenols such as butylphenol, phenolic compounds such as n-octadecyl-3-(4'-hydroxy-3',5'-di-tert-butylphenol)propionate, and aromatic amine compounds such as naphthylamines or dialkyldiphenylamines; extreme pressure agents such as sulfurized olefins, sulfurized oils and fats, methyl trichlorostearate, chlorinated naphthalene, benzyl iodide, fluoroalkylpolysiloxane, and lead naphthenate; rust inhibitors such as carboxylic acids such as stearic acid, dicarboxylic acids, metal soaps, carboxylic acid amine salts, metal salts of heavy sulfonic acids, and carboxylic acid partial esters of polyhydric alcohols; and corrosion inhibitors such as benzotriazole and benzimidazole.

[0037] The grease composition according to this embodiment is produced by mixing predetermined amounts of a base oil, modified silicone, thickener, and solid lubricant by a known method, and adding at least one of the above-mentioned additives as needed.

[0038] <Control Cable> The control cable according to this embodiment is constructed by inserting an inner cable into an outer casing, and applying the grease composition according to this embodiment to the outer circumferential surface of the inner cable. The outer circumferential surface of the inner cable is made of resin or metal, and the inner circumferential surface of the outer casing is made of resin.

[0039] The amount of grease composition applied per unit area to the outer surface of the inner cable should be 45-220 g / m², from the viewpoint of balancing wear suppression effect and lubrication performance. 2 Preferably, 50-210 g / m² 2 This is more preferable. The amount applied per unit area to the outer surface of the inner cable can be the amount of grease composition interposed per unit area between the outer surface of the inner cable and the inner surface of the outer casing.

[0040] Here, we will describe the "outer surface of the inner cable" which serves as the basis for determining the amount of grease composition to be applied. The outer surface of the inner cable is a hypothetical circumferential surface that is in contact with the outermost strand in the radial direction of the inner cable. As shown in Figure 1, if a coating layer 69 is provided on the radially outer side of the strand wire 63, the outer surface of the inner cable becomes the outer surface of the coating layer 69. As shown in Figure 2, the surface of the strand wire 22 facing radially outward becomes the outer surface of the inner cable.

[0041] This embodiment is not limited to the configurations of the inner cable and outer casing. The following outlines the configurations of the inner cable and outer casing.

[0042] The inner cable is preferably constructed by twisting strand side wires onto the outer surface of a shaft or strand core wire. A coating layer or clearance may also be provided on the radially outer side of the strand side wires. The shaft is preferably made of a material that has moderate rigidity while also possessing toughness, such as carbon steel wire or carbon fiber. The strands, like the shaft, are preferably made of a material that has moderate rigidity while also possessing toughness. The coating layer covers the strands and may be made of a material with moderate rigidity, similar to the shaft, or of a resin such as nylon 66.

[0043] The outer casing preferably consists of three layers: a liner through which the inner cable is inserted, a shield wire, and a coating layer. The liner may be made of a resin such as polypropylene or polyester. The shield wire is arranged on the outer surface of the liner and twisted in a predetermined direction, and may be made of a material that has appropriate rigidity and toughness, similar to the shaft of the inner cable. The coating layer covers the shield wire and may be made of a resin such as polypropylene or polyester. [Examples]

[0044] The embodiments will be described in more detail below with reference to examples, but the present invention is not limited to these.

[0045] In this example, the following raw materials were used. Base oil: Dimethylpolysiloxane (Kinematic viscosity at 25°C: 500 mm) 2 / s) Modified Silicone 1: DOWSIL BY 16-880 Fluid (represented by general formula (2)), manufactured by Dow Toray Ltd., with side chains modified by carboxyl groups, kinematic viscosity at 25°C: 2200 mmHg 2 / s) Modified Silicone 2: DOWSIL CF 1029 (represented by general formula (2)), manufactured by Dow Toray Ltd., with side chains modified by amino groups, kinematic viscosity at 25°C: 1200 mmHg 2 / s) Thickener: S7000 (Lithium Stearate) manufactured by Sakai Chemical Industry Co., Ltd. MCA1: Melamine cyanurate (volume-average particle size: 5.0 μm) MCA2: Melamine cyanurate (volume-average particle size: 14.0 μm) PTFE: Polytetrafluoroethylene (Volume-average particle size: 4.0 μm)

[0046] <Preparation of grease composition> Each test grease composition was obtained by thoroughly stirring the various raw materials in a heat-resistant container according to the formulations listed in Table 1 to disperse the thickener, and then performing a milling process.

[0047] [Table 1]

[0048] <Making Control Cable 50> Using the obtained grease composition, a control cable 50, as shown in Figure 1, was fabricated. Figure 1 is a schematic diagram showing a cross-section of the control cable 50.

[0049] Specifically, an inner cable 60 and an outer casing 70 constituting the control cable 50 were prepared. The inner cable 60 consists of a strand core wire 61, strand side wires 63, and a coating layer 69. In the strand side wires 63, six second strand side wires 65 are arranged on the outer surface of the strand core wire 61 and twisted in the Z direction, while six third strand side wires 67A and six first strand side wires 67B are arranged outside the second strand side wires 65 so as to alternate in the circumferential direction and are twisted in the S direction. The strand side wires 63 thus constructed are covered with a coating layer 69.

[0050] The strand core wire 61, the second strand side wire 65, the third strand side wire 67A, and the first strand side wire 67B are made of carbon steel wire rods specified in SWRH62B of JIS G 3506, which have been zinc-plated, and the coating layer 69 is made of nylon 66 resin (product name "Leona" manufactured by Asahi Kasei Corporation).

[0051] The outer diameter of the inner cable 60 is 4.3 mm, the wire diameter of the strand core wire 61 is 0.65 mm, the wire diameter of the second strand side wire 65 is 0.6 mm, the wire diameter of the third strand side wire 67A is 0.7 mm, and the wire diameter of the first strand side wire 67B is 0.5 mm.

[0052] The outer casing 70 is composed of a liner 71 through which the inner cable 60 is inserted, 20 shield wires 73, and a coating layer 75. The shield wires 73 are arranged on the outer surface of the liner 71 and twisted in the Z direction, and are covered with the coating layer 75.

[0053] Liner 71 is made of a thermoplastic resin containing potassium titanate fibers (product name "Pochicon" manufactured by Otsuka Chemical Co., Ltd.), shield wire 73 is made of a carbon steel wire rod specified in SWRH62A of JIS G 3506 that has been zinc-plated, and coating layer 75 is made of a polyester thermoplastic elastomer (product name "Perprene" manufactured by Toyobo Co., Ltd.).

[0054] The outer casing 70 has an outer diameter of 9.0 mm, the liner 71 has an outer diameter of 6.0 mm, the liner 71 has an inner diameter of 4.6 mm, and the shield wire 73 has a wire diameter of 0.884 mm.

[0055] Then, each of the obtained test grease compositions was applied at a rate of 63 g / m² per unit area. 2 The inner cable 60 was coated with the coating on its outer surface, and the inner cable 60 was inserted into the liner 71 of the outer casing 70 to obtain the control cable 50.

[0056] <Durability Test> A durability test was conducted on the obtained control cable 50. Figure 3 is a schematic plan view of the apparatus used for the durability test.

[0057] Specifically, the control cable 50 was routed in the shape described in "Routing" in Table 9 and placed inside the constant temperature chamber 91. Then, a spring 95 was connected to one end of the inner cable 60 to apply a test load W, and the other end of the inner cable 60 was moved back and forth at a speed of 30 cpm (cycles / min) and a stroke length of 30 mm using a push-pull force measuring instrument 93. The unloaded sliding resistance and operating load F (tensile force) were measured initially and after 1 million cycles, respectively. The load efficiency was then calculated initially and after 1 million cycles using the formula (Load Efficiency (%)) = {(Test Load W) / (Operating Load F)} × 100. This test was performed by changing the temperature of the constant temperature chamber 91 to 130°C, 25±5°C, and -40°C, and evaluated according to the evaluation criteria in Tables 2, 3, and 4. A higher load efficiency indicates that wear on the outer surface of the inner cable and the inner surface of the outer casing is suppressed. The results are shown in Table 8.

[0058] [Table 2]

[0059] [Table 3]

[0060] [Table 4]

[0061] <Stick-slip test> Under the conditions of the aforementioned durability test, the stick-slip ratio of the inner cable 60 was calculated initially and after 1 million cycles. Specifically, the operating load F1, derived from the static friction coefficient required to start the inner cable 60 from a stationary state, and the operating load F2, derived from the dynamic friction coefficient required to move the inner cable 60 at a constant speed, were monitored, and the stick-slip ratio F1 / F2 was calculated. This test was conducted by changing the temperature of the constant temperature chamber 91 to 130°C, 25±5°C, and -40°C, and the stick-slip resistance performance was evaluated according to the evaluation criteria in Tables 5, 6, and 7. The results are shown in Table 8.

[0062] [Table 5]

[0063] [Table 6]

[0064] [Table 7]

[0065] [Table 8]

[0066] [Table 9]

[0067] <Making control cable 10> Using the obtained grease composition, a control cable 10, as shown in Figure 2, was fabricated. Figure 2 is a schematic diagram showing a cross-section of the control cable 10.

[0068] Specifically, an inner cable 20 and an outer casing 30 constituting the control cable 10 were prepared. The inner cable 20 consists of a shaft 21 and 12 strands of wire 22, with the strands 22 arranged on the outer surface of the shaft 21 and twisted in the S direction.

[0069] The shaft 21 is made of carbon steel wire rod specified in JIS G 3506 SWRH72A that has been treated with oil tempering, and the strand wire 22 is made of carbon steel wire rod specified in JIS G 3506 SWRH62B that has been galvanized.

[0070] The outer diameter of the inner cable 20 is 2.2 mm, the outer diameter of the shaft 21 is 1.4 mm, and the wire diameter of the stranded wire 22 is 0.4 mm. Here, the outer diameter of the inner cable 20 can be the diameter of the circumscribed circle 41 of the stranded wire 22.

[0071] Furthermore, the outer casing 30 consists of a liner 31 through which the inner cable 20 is inserted, 20 shield wires 33, and a coating layer 35. The shield wires 33 are arranged on the outer surface of the liner 31 and twisted in the Z direction, and are covered with the coating layer 35.

[0072] The liner 31 is made of polybutylene terephthalate resin (product name "Duranex" manufactured by Polyplastics Co., Ltd.), the shield wire 33 is made of carbon steel wire rod specified in SWRH62A of JIS G 3506 and coated with zinc, and the coating layer 35 is made of polyester thermoplastic elastomer (product name "Perprene" manufactured by Toyobo Co., Ltd.).

[0073] The outer diameter of the outer casing 30 is 7.1 mm, the outer diameter of the liner 31 is 3.95 mm, the inner diameter of the liner 31 is 2.35 mm, and the wire diameter of the shield wire 33 is 0.7 mm.

[0074] Then, each of the obtained test grease compositions was applied at a rate of 103 g / m² per unit area.2 The inner cable 20 was coated with the coating on its outer surface, and the inner cable 20 was inserted into the liner 31 of the outer casing 30 to obtain the control cable 10.

[0075] <Durability Test> A durability test was conducted on the obtained control cable 10. Figure 3 is a schematic plan view of the apparatus used for the durability test.

[0076] Specifically, the control cable 10 was routed in the shape described in "Routing" in Table 17 and placed inside the constant temperature chamber 91. Then, a spring 95 was connected to one end of the inner cable 20 to apply a test load W, and the other end of the inner cable 20 was moved back and forth at a speed of 30 cpm (cycles / min) and a stroke length of 30 mm using a push-pull force measuring instrument 93. The unloaded sliding resistance and operating load F (tensile force) were measured initially and after 1 million cycles, respectively. The load efficiency was then calculated initially and after 1 million cycles using the formula (Load Efficiency (%)) = {(Test Load W) / (Operating Load F)} × 100. This test was performed by changing the temperature of the constant temperature chamber 91 to 130°C, 25±5°C, and -40°C, and evaluated according to the evaluation criteria in Tables 10, 11, and 12. A higher load efficiency indicates that wear on the outer surface of the inner cable and the inner surface of the outer casing is suppressed. The results are shown in Table 16.

[0077] [Table 10]

[0078] [Table 11]

[0079] [Table 12]

[0080] <Stick-slip test> Under the conditions of the aforementioned durability test, the stick-slip ratio of the inner cable 60 was calculated initially and after 1 million cycles. Specifically, the operating load F1, derived from the static friction coefficient required to start the inner cable 60 from a stationary state, and the operating load F2, derived from the dynamic friction coefficient required to move the inner cable 60 at a constant speed, were monitored, and the stick-slip ratio F1 / F2 was calculated. This test was conducted by changing the temperature of the constant temperature chamber 91 to 130°C, 25±5°C, and -40°C, and the stick-slip resistance performance was evaluated according to the evaluation criteria in Tables 13, 14, and 15. The results are shown in Table 16.

[0081] [Table 13]

[0082] [Table 14]

[0083] [Table 15]

[0084] [Table 16]

[0085] [Table 17]

[0086] The results in Tables 8 and 16 show that a control cable coated with the grease composition according to this embodiment, which contains a base oil, modified silicone, thickener, and two or more types of melamine cyanurate with different volume-average particle sizes, maintains or reduces no-load sliding resistance over a wide temperature range, and comprehensively improves wear resistance and stick-slip resistance, compared to a case where PTFE is used as a solid lubricant. [Explanation of Symbols]

[0087] 10 control cables 20 Inner Cables 21 Shaft 22 strands 30 Outer casing 31 Liner 33 Shielded wire 35 Coat Layers 41 Circumscribed circle 50 Control Cables 60 Inner Cable 61 Stranded core wire 63 Strand Siding 65 Second Strand Siding 67A Third Strand Siding 67B First Strand Siding 69 Coat Layers 70 Outer casing 71 Liner 73 Shielded wire 75 Coat Layers 91 Constant temperature bath 93 Push / pull force measuring device 95 Spring

Claims

1. A grease composition comprising a base oil, modified silicone, thickener, and solid lubricant, The solid lubricant is a grease composition containing two or more melamine cyanurates with different volume-average particle sizes.

2. The solid lubricant comprises melamine cyanurate (MCA1) with a volume-average particle diameter of 6.0 μm or less, and melamine cyanurate (MCA2) with a volume-average particle diameter of 10 to 30 μm. The grease composition according to claim 1, wherein the mass content ratio of MCA1 to MCA2 in the solid lubricant is 60:40 to 99.9:0.

1.

3. The grease composition according to claim 1 or 2, wherein the total content of melamine cyanurate in the grease composition is 1 to 30% by mass.

4. The grease composition according to claim 1 or 2, wherein the base oil contains a silicone base oil, and the content of the silicone base oil in the grease composition is 45% by mass or more and 70% by mass or less.

5. The modified silicone is defined by the following general formulas (1), (2), or (3): [wherein, R 1 and R 2 each independently represents -W 1 -COOH, or -W 1 -NH 2 ; when there are a plurality of R 3 , each independently represents -W 1 -COOH, -W 1 -NH 2 , or -W 1 -NH-W 2 -NH 2 ; R represents a linear or branched alkyl group having 1 to 30 carbon atoms; R 4 represents -W 1 -COOH; when there are a plurality of W 1 and W 2 , each independently represents a linear or branched alkylene group having 1 to 30 carbon atoms; m and n each independently represent a repetition number of 1 or more], which is one or more modified silicones selected from the group consisting of compounds represented by the following formula: The grease composition according to claim 1 or 2.

6. The grease composition according to claim 1 or 2, wherein the content of the modified silicone in the grease composition is 0.01 to 10% by mass.

7. A control cable in which the grease composition according to claim 1 is applied to the outer surface of the inner cable.

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