Grease composition for control cables and control cables

Abstract

To provide a grease composition for a control cable which can remarkably suppress stick-slip and wear in long-period use by applying the grease composition to an outer peripheral surface of an inner cable or an inner peripheral surface of an outer casing, or the like.SOLUTION: A grease composition for a control cable contains: a silicone base oil; an amino-modified silicone; a thickener; a layered structure compound powder including tungsten disulfide; and a polytetrafluoroethylene powder. The content of the tungsten disulfide is 0.1 to 5.0 mass%.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a grease composition for a control cable and a control cable. [Background technology]

[0002] A control cable transmits the force or movement of a user's operation to a location far away from the user's hand, and is configured by inserting an inner cable slidably through an outer casing (Patent Documents 1 to 3, etc.). For example, when the movement of a gear shift lever of an automobile is transmitted to a transmission via a control cable, when the user operates the gear shift lever, the inner cable is pushed and pulled, and thus the operating force of the user is transmitted to the transmission.

[0003] In such control cables, grease is often applied to the outer peripheral surface of the inner cable or the inner peripheral surface of the outer casing, which reduces the resistance (sliding resistance) that occurs when the inner cable slides on the inner peripheral surface of the outer casing, thereby preventing a decrease in load efficiency. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 7-71434 [Patent Document 2] JP 2000-314416 A [Patent Document 3] JP 2007-321989 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, with conventional grease, the lubricating performance may decrease as the number of times the inner cable slides on the inner surface of the outer casing (hereinafter sometimes referred to as "endurance number") increases, which may cause a decrease in the load efficiency of the control cable. More specifically, the inner surface of the outer casing peels off due to sliding against the outer surface of the inner cable, generating wear powder that reduces the lubricating performance of the grease. The decrease in the lubricating performance of the grease then causes an increase in wear powder, accelerating the decrease in the lubricating performance of the grease and causing a decrease in the load efficiency of the control cable.

[0006] To improve this, it may be possible to develop a grease that is excellent at suppressing wear on the outer circumferential surface of the inner cable or the inner circumferential surface of the outer casing and maintaining this state even when the durability is increased, for example.

[0007] Grease also requires anti-stick-slip properties to provide stable low torque performance over a long period of time. Stick-slip is a vibration phenomenon caused by repeated adhesion and sliding of microscopic friction surfaces between friction surfaces, and occurs when the friction coefficient decreases with increasing sliding speed, or when there is a discontinuous decrease in friction when moving from static friction to kinetic friction.

[0008] An object of the present invention is to provide a grease composition for control cables that can significantly suppress stick-slip and wear during long-term use by applying it to the outer peripheral surface of an inner cable or the inner peripheral surface of an outer casing, etc. [Means for solving the problem]

[0009] The present inventors have discovered that a grease composition containing a silicone base oil, an amino-modified silicone, a thickener, polytetrafluoroethylene (PTFE) powder, and a specified amount of tungsten disulfide can solve the above-mentioned problems, and have completed the present invention.

[0010] That is, the present invention provides [1] A grease composition for a control cable, comprising a silicone base oil, an amino-modified silicone, a thickener, a layered compound powder containing tungsten disulfide, and a polytetrafluoroethylene powder, the grease composition having a tungsten disulfide content of 0.1 to 5.0 mass %; [2] The grease composition according to the above [1], wherein the total content of the layered compound powder and the polytetrafluoroethylene powder is 5 to 30 parts by mass per 100 parts by mass of the silicone base oil. [3] The grease composition according to the above [1] or [2], wherein the content of the amino-modified silicone is 1.0 to 13 parts by mass per 100 parts by mass of the silicone base oil. [4] The grease composition according to any one of the above [1] to [3], wherein the volume average particle diameter of the tungsten disulfide is less than 9.0 μm. [5] The kinetic viscosity of the silicone base oil at 25 ° C. is 50 to 2000 mm 2 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 amino-modified silicone is a silicone whose side chain is modified with an amino group. [7] The grease composition according to any one of the above [1] to [6], wherein the compound powder having a layered structure consists of the tungsten disulfide. [8] The grease composition according to any one of the above [1] to [7], wherein the thickener is a lithium soap-based thickener. [9] The grease composition according to any one of the above [1] to [8], wherein the content of the silicone base oil is 50 to 89 mass%.

[10] The grease composition according to any one of [1] to [9] above, wherein the content of the thickener is 5 to 44 mass%.

[11] A control cable having an outer circumferential surface of an inner cable and an inner circumferential surface of an outer casing, the control cable comprising the grease composition according to any one of the above [1] to

[10] applied thereto. Effect of the Invention

[0011] According to the present invention, there is provided a grease composition for control cables that can significantly suppress stick-slip and wear during long-term use. [Brief description of the drawings]

[0012] [Figure 1] 2 is a cross-sectional view of a control cable according to an embodiment of the present invention. FIG. [Diagram 2] FIG. 2 is a schematic plan view of an apparatus used in a durability test. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] The method for producing a control cable, including the method for producing a grease composition according to this embodiment, will be described in detail below. However, the following description is an example for explaining this embodiment, and is not intended to limit the technical scope of the present invention to only this described range. In this specification, when a numerical range is indicated using "~", it is intended to include both ends of the numerical range.

[0014] <Grease composition> The grease composition according to the present embodiment contains, as essential components, a silicone base oil, an amino-modified silicone, a thickener, a layered compound powder containing tungsten disulfide, and a polytetrafluoroethylene powder. The content of each of the above components contained in the grease composition according to the present embodiment can be appropriately selected from the ranges described above so that the total content in the grease composition is 100 mass% or less.

[0015] (Silicone base oil) Examples of silicone base oils include dimethyl silicone oils such as dimethyl polysiloxane (dimethicone) and high polymerization methyl polysiloxane; methyl phenyl silicone oils such as methyl phenyl polysiloxane; cyclic silicone oils such as methyl cyclopolysiloxane, octamethyl cyclotetrasiloxane, decamethyl cyclopentasiloxane, and dodecamethyl cyclohexasiloxane; modified silicones such as polyether modified silicone, carboxy modified silicone, fatty acid modified silicone, alcohol modified silicone, aliphatic alcohol modified silicone, epoxy modified silicone, fluorine modified silicone, and alkyl modified silicone; methyl hydrogen polysiloxane, dimethiconol, etc. These silicone base oils may be used alone or in combination of two or more. It should be noted that silicone base oils do not include amino modified silicones, which will be described later.

[0016] The kinetic viscosity of silicone base oil at 25°C is 50 to 2000 mm 2 / s is preferable, and 100 to 1500 mm 2 / s is more preferable, and 200 to 1000 mm 2 / s is more preferable. 2 By setting the kinetic viscosity at 2000 mm / s or more, a sufficient oil film is formed on the outer peripheral surface of the inner cable or the inner peripheral surface of the outer casing of the silicone base oil at 25°C. This suppresses wear on the outer peripheral surface of the inner cable or the inner peripheral surface of the outer casing, and as a result, it is possible to prevent a decrease in load efficiency. 2 By setting the kinematic viscosity at 1 / s or less, the amount of the grease composition that penetrates between the outer circumferential surface of the inner cable and the inner circumferential surface of the outer casing is reduced, and it is possible to prevent the sliding resistance from increasing. Note that the kinematic viscosity of the base oil in this specification is a value measured at 25°C using a glass capillary viscometer in accordance with JIS K 2283:2000.

[0017] The content of the silicone base oil in the grease composition is preferably 50 to 89 mass %, more preferably 60 to 85 mass %, from the viewpoints of preventing hardening of the grease composition and excessive oil separation and ensuring the durability of the control cable.

[0018] (Amino modified silicone) The grease composition according to the present embodiment contains an amino-modified silicone as an essential component. By blending the amino-modified silicone, the stick-slip resistance of the grease composition can be significantly improved.

[0019] Examples of amino-modified silicones include silicones whose terminals are modified with alkylamino groups, and silicones whose side chains are modified with alkylamino groups, with silicones whose side chains are modified with alkylamino groups being preferred.

[0020] The content of amino-modified silicone relative to 100 parts by mass of silicone base oil is preferably 1.0 parts by mass or more, more preferably 1.5 parts by mass or more, even more preferably 2.0 parts by mass or more, even more preferably 2.5 parts by mass or more, and particularly preferably 3.0 parts by mass or more. By making the content of amino-modified silicone 1.0 parts by mass or more, sufficient stick-slip resistance tends to be obtained. On the other hand, the content of amino-modified silicone relative to 100 parts by mass of silicone base oil is preferably 13 parts by mass or less, more preferably 12 parts by mass or less, even more preferably 11 parts by mass or less, even more preferably 10 parts by mass or less, and particularly preferably 9.0 parts by mass or less. If the content of amino-modified silicone base oil is more than 13 parts by mass, there is a concern about the hardening of grease over time and the influence on resin.

[0021] The grease composition according to the present embodiment may or may not contain a base oil other than the silicone base oil and the amino-modified silicone. The content of the base oil other than the silicone base oil and the amino-modified silicone in the grease composition is preferably less than 5.0 mass%, more preferably less than 1.0 mass%, and even more preferably less than 0.1 mass%.

[0022] (Thickener) The thickener is not particularly limited as long as it is a material that is normally used as a thickener for grease. Specific examples of the thickener include metal soap-based thickeners, complex metal soap-based thickeners, and urea-based compounds, and lithium soap-based thickeners are preferred.

[0023] The lithium soap thickener (lithium soap) is not particularly limited, but may be a lithium salt of a higher fatty acid having 10 to 28 carbon atoms, a lithium salt of a higher hydroxy fatty acid having 10 to 28 carbon atoms and having one or more hydroxyl groups, or a mixture thereof. Examples of the higher fatty acid include lauric acid, palmitic acid, stearic acid, linoleic acid, arachidic acid, myristic acid, pentadecanoic acid, heptadecanoic acid, oleic acid, arachidonic acid, and behenic acid, and stearic acid is preferred because of its good consistency yield (degree of hardening of the grease). Examples of the higher hydroxy fatty acid include 12-hydroxystearic acid, 12-hydroxylauric acid, and 16-hydroxypalmitic acid, and 12-hydroxystearic acid is preferred because it is easily available and inexpensive.

[0024] Specific examples of lithium soaps include lithium laurate, lithium stearate, lithium 12-hydroxystearate, and mixtures thereof.

[0025] The content of the thickener in the grease composition is preferably 5 to 44 mass%, more preferably 7 to 40 mass%, further preferably 9 to 35 mass%, and particularly preferably 11 to 30 mass%. By making the content of the thickener 5 mass% or more, it is possible to prevent the frictional force generated when the inner cable slides from increasing and the load efficiency from decreasing. On the other hand, by making the content of the thickener 44 mass% or less, it is possible to ensure the life of the grease composition.

[0026] (Layered compound powder) The layered compound powder is a powder of a compound having a layered crystal structure, and is, for example, a powder of an intercalation compound such as tungsten disulfide, molybdenum disulfide, graphite, graphite fluoride, mica, MCA (Melamine Cyanurate Acid), boron nitride, transition metal dichalcogenide, etc. The layered compound powder according to this embodiment contains tungsten disulfide as an essential component, and may contain a layered compound powder other than the tungsten disulfide, but it is preferable that the layered compound powder is composed of only tungsten disulfide.

[0027] From the viewpoint of wear suppression effect, the content of the layered compound powder in the grease composition is preferably 1 mass % or more, more preferably 3 mass % or more, and even more preferably 5 mass % or more. Also, the content of the layered compound powder in the grease composition is preferably 20 mass % or less, more preferably 15 mass % or less, and even more preferably 10 mass % or less.

[0028] The content of tungsten disulfide in the grease composition is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, even more preferably 1.0% by mass or more, even more preferably 1.5% by mass or more, and particularly preferably 1.8% by mass or more. The content is preferably 5.0% by mass or less, more preferably 4.5% by mass or less, even more preferably 4.0% by mass or less, even more preferably 3.5% by mass or less, and particularly preferably 3.2% by mass or less. By setting the content of tungsten disulfide within the above range, excellent effects are exhibited in the load efficiency and no-load sliding resistance in the cable durability test. In addition, by setting the content of tungsten disulfide to 5.0% by mass or less, hardening of the grease composition and excessive oil separation can be prevented, and the durability of the control cable can be ensured.

[0029] The proportion of tungsten disulfide in the layered structure compound powder is preferably 50 mass % or more, more preferably 70 mass % or more, further preferably 90 mass % or more, and particularly preferably 100 mass %.

[0030] The volume average particle diameter of tungsten disulfide is preferably 0.1 μm or more, more preferably 0.2 μm or more, even more preferably 0.3 μm or more, even more preferably 0.4 μm or more, and particularly preferably 0.5 μm or more. The volume average particle diameter of tungsten disulfide is preferably less than 9.0 μm, more preferably 8.0 μm or less, even more preferably 7.0 μm or less, even more preferably 5.0 μm or less, even more preferably 3.0 μm or less, even more preferably 2.0 μm or less, and particularly preferably 1.5 μm or less. By setting the volume average particle diameter of tungsten disulfide within the above range, the effect of suppressing wear of the outer peripheral surface of the inner cable or the inner peripheral surface of the outer casing can be further improved. The volume average particle diameter in this specification is a value measured according to a laser diffraction scattering method.

[0031] (Polytetrafluoroethylene powder) By blending tungsten disulfide, it is possible to impart excellent wear resistance and low friction properties to the grease composition, but since the specific gravity of tungsten disulfide is higher than that of the base oil, it is thought that it has a tendency to promote oil separation. In this way, while the lubrication properties are improved by oil separation, if the degree of oil separation is too high, the oil film is likely to break, and there is a concern that the surroundings of the sliding parts will be contaminated by scattering. Therefore, by using PTFE in combination, not only is the wear suppression effect and low friction properties improved, but the stability of the degree of oil separation is maintained, making it possible to achieve moderate oil separation over a long period of time, which is thought to lead to a longer life (in cable durability tests). In addition, moderate oil separation is, for example, in accordance with JIS K 2220 11, preferably 1.0 to 30 mass %, more preferably 1.5 to 25 mass %, and even more preferably 2.0 to 20 mass % at 100 ° C. for 1000 h.

[0032] Polytetrafluoroethylene (PTFE) has an overall band-like structure, and the band has a band structure in which plate-like crystal portions and amorphous portions are alternately arranged in a sandwich shape.

[0033] From the viewpoint of oil separation rate and wear suppression effect, the content of the PTFE powder in the grease composition is preferably 4.9% by mass or more, more preferably 5.5% by mass or more, even more preferably 6.0% by mass or more, even more preferably 6.5% by mass or more, even more preferably 7.0% by mass or more, and particularly preferably 7.5% by mass or more. The content of the PTFE powder in the grease composition is preferably 29% 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 volume average particle diameter of the PTFE powder is preferably 0.1 μm or more, more preferably 0.5 μm or more, even more preferably 1.0 μm or more, and particularly preferably 1.5 μm or more. The volume average particle diameter of the PTFE is preferably 25 μm or less, more preferably 15 μm or less, even more preferably 10 μm or less, and particularly preferably 7.0 μm or less. By setting the volume average particle diameter of the PTFE within the above range, the effect of suppressing wear of the outer peripheral surface of the inner cable or the inner peripheral surface of the outer casing can be further improved. Note that the volume average particle diameter in this specification is a value measured according to a laser diffraction scattering method.

[0035] The total content of the layered compound powder and the PTFE powder relative to 100 parts by mass of the silicone base oil is preferably 5 to 30 parts by mass, more preferably 7 to 25 parts by mass, even more preferably 9 to 22 parts by mass, and particularly preferably 11 to 19 parts by mass. By making the total content 5 parts by mass or more, it is possible to suppress wear and achieve low friction. On the other hand, by making the total content 30 parts by mass or less, it is possible to obtain an appropriate consistency, prevent excessive oil separation of the grease composition, and ensure the durability of the control cable.

[0036] The content of the layered compound powder relative to the total content of the layered compound powder and the PTFE powder is preferably 10% by mass or more, more preferably 15% by mass or more, even more preferably 18% by mass or more, and particularly preferably 20% by mass or more, from the viewpoint of the wear suppression effect. Also, the content of the layered compound powder relative to the total content of the layered compound powder and the PTFE powder is preferably 60% by mass or less, more preferably 50% by mass or less, even more preferably 45% by mass or less, and particularly preferably 40% by mass or less, from the viewpoint of the wear suppression effect.

[0037] (Other additives) The grease composition according to the present embodiment may further contain one or more of the additives listed below. Examples of the 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 succinimides, boron-modified alkenyl succinimides, benzylamines, and alkyl polyamines; anti-wear agents such as methylene bisdithiocarbamate, polycarboxylates, zinc-based anti-wear agents, sulfur-based anti-wear agents, and phosphorus-based anti-wear agents; thickeners such as polymethacrylates, ethylene propylene copolymers, styrene-isoprene copolymers, hydrogenated styrene-isoprene copolymers, and polyisobutylene; alkylphenols such as 2,6-di-tert-butyl-p-cresol, 4,4'-methylene bis-(2,6-di- antioxidants such as bisphenols such as n-octadecyl-3-(4'-hydroxy-3',5'-di-tert-butylphenol)propionate, 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, amine salts of carboxylic acids, metal salts of heavy sulfonic acids, and partial esters of carboxylic acids of polyhydric alcohols; and corrosion inhibitors such as benzotriazole and benzimidazole.

[0038] The grease composition according to this embodiment is produced by mixing predetermined amounts of the silicone base oil, the amino-modified silicone, the thickener, the powder of the compound having a layered structure containing tungsten disulfide, and the polytetrafluoroethylene powder in a known manner, and adding at least one of the additives described above, as necessary.

[0039] <Control cable> The control cable according to this embodiment is configured by inserting an inner cable into an outer casing and applying the grease composition according to this embodiment to the outer peripheral surface of the inner cable and the inner peripheral surface of the outer casing, as shown in Fig. 1. The outer peripheral surface of the inner cable is configured from resin or metal, and the inner peripheral surface of the outer casing is configured from resin.

[0040] The amount of the grease composition applied per unit area on the outer peripheral surface of the inner cable and the inner peripheral surface of the outer casing is, for example, 30.0 to 200.0 g / m from the viewpoint of the balance between the wear suppression effect and the lubricating performance. 2 , 35.0~150.0g / m 2 , 40.0~100.0g / m 2 It can be said that:

[0041] Here, the "outer peripheral surface of the inner cable" which is the basis for the amount of grease composition to be applied will be described. When the inner cable is composed of two layers, a shaft and a strand (as shown in FIG. 1 described later), the "outer peripheral surface of the inner cable" is a virtual peripheral surface that contacts the strand side wire 27 located at the outermost position in the radial direction of the inner cable. When a clearance 41 is provided on the radial outside of the inner cable 20 as shown in FIG. 1, the "outer peripheral surface of the inner cable" is the outer peripheral surface of the clearance 41.

[0042] In the present embodiment, the configurations of the inner cable and the outer casing are not limited to those described above. The configurations of the inner cable and the outer casing will be outlined below.

[0043] The inner cable may be made of two layers, a shaft and a strand, or it may be made of three layers, a shaft, a strand, and a coating layer. As shown in FIG. 1, the strand is made of a strand core wire 25 and a strand side wire 27. The shaft is preferably made of a material having appropriate rigidity and toughness, such as a carbon steel wire or carbon fiber. The strand is arranged on the outer circumferential surface of the shaft and twisted in a predetermined direction, and may be made of the same material as the shaft, having appropriate rigidity and toughness. The coating layer is made of the strand. It may be made of a material having a suitable rigidity like the shaft, or may be made of a resin such as PA (polyamide)66.

[0044] The outer casing preferably comprises three layers: a liner through which the inner cable is inserted, a shield, and a coating layer. The liner may be made of resin, and is preferably made of PTFE resin. This provides the effect of improving the sliding performance with the inner cable. The shield is disposed on the outer peripheral surface of the liner and twisted in a predetermined direction, and may be made of a material having appropriate rigidity and toughness, like the shaft of the inner cable. The coating layer covers the shield, and may be made of a resin such as PP (polypropylene) resin or polyester elastomer (hereinafter referred to as "TPC"). EXAMPLES

[0045] The present embodiment will be described in more detail below with reference to examples, but the present invention is not limited to these.

[0046] In this example, the following raw materials were used: Silicone base oil: Dimethylpolysiloxane Amino-modified silicone: DOWSIL CF 1029 (silicone whose side chains are modified with alkylamino groups) manufactured by Dow Toray Co., Ltd. Thickener: S7000 (lithium stearate) manufactured by Sakai Chemical Industry Co., Ltd. Tungsten disulfide 1: Powder, volume average particle size 0.6 μm Tungsten disulfide 2: Powder, volume average particle size 7.0 μm Boron nitride: Powder, volume average particle size 1.5 μm PTFE: Powder, volume average particle size 4.0μm

[0047] <Preparation of grease composition> According to the formulations shown in Table 1, the various raw materials were thoroughly stirred to disperse the lithium soap, and then milling was performed to obtain each test grease composition in which the lithium soap was dispersed in the silicone base oil.

[0048] <Preparing the control cable> The obtained grease composition was used to produce a control cable 10 shown in Fig. 1. Fig. 1 is a schematic diagram showing a cross section of the control cable 10.

[0049] Specifically, an inner cable 20 and an outer casing 30 constituting the control cable 10 were prepared. The inner cable 20 is composed of a shaft 21 and nine strands 23, and the strands 23 are arranged on the outer circumferential surface of the shaft 21 and twisted in the S direction. Each strand 23 is composed of a strand core wire 25 and six strand side wires 27, and the strand side wires 27 are arranged on the outer circumferential surface of the strand core wire 25 and twisted in the Z direction. Furthermore, a clearance 41 was provided on the radially outer side of the inner cable 20.

[0050] The shaft 21 is made of a carbon steel wire rod specified by SWRH72A of JIS G 3506 that has been subjected to oil tempering. The strand core wire 25 and the strand side wire 27 are each made of a carbon steel wire rod specified by SWRH62A of JIS G 3506 that has been galvanized and then drawn.

[0051] The outer diameter of the inner cable 20 is 2.92 mm, the outer diameter of the shaft 21 is 1.6 mm, the outer diameter of the strand core wire 25 is 0.265 mm, and the outer diameter of the strand side wire 27 is 0.24 mm.

[0052] The outer casing 30 is composed of a liner 31 through which the inner cable 20 is inserted, twenty shields 33, and a coating layer 35. The shields 33 are disposed on the outer peripheral surface of the liner 31 and twisted in the Z direction, and are covered with the coating layer 35.

[0053] The liner 31 is made of PTFE resin (product name "Hyflon" manufactured by Nissei Electric Co., Ltd.), the shield 33 is made of zinc-plated carbon steel wire material specified in SWRH62A of JIS G 3506, and the coating layer 35 is made of PP resin (product name "Zelas" manufactured by Mitsubishi Chemical Corporation).

[0054] The outer diameter of the outer casing 30 is 8.2 mm, the inner diameter of the liner 31 is 3.2 mm, the outer diameter of the liner 31 is 4.5 mm, and the outer diameter of the shield 33 is 0.8 mm.

[0055] Each of the obtained test grease compositions was applied in an amount of 50.0 g / m 2 The outer circumferential surface of the clearance 41 and the inner circumferential surface of the outer casing 30 were coated with the above-mentioned mixture, and the inner cable 20 was inserted into the liner 31 of the outer casing 30 to obtain the control cable 10.

[0056] <Durability test> A durability test was carried out on the obtained control cable 10. Fig. 2 is a schematic plan view of an apparatus used in the durability test.

[0057] Specifically, the control cable 10 was arranged in the shape described in "Arrangement" in Table 2 and placed in the thermostatic chamber 91. After that, a spring 95 was connected to one end of the inner cable 20, a test load W was applied, and the other end of the inner cable 20 was reciprocated by a push-pull force measuring device 93 at a speed of 30 cpm (cycles / min) and a stroke length of 30 mm, and the operation load F (tensile force) was measured. Then, the load efficiency for each number of reciprocations (endurance number) was calculated by (load efficiency (%)) = {(test load W) / (operation load F)} × 100. This test was performed by changing the temperature of the thermostatic chamber 91 to 130°C and 25°C, and evaluated according to the following evaluation criteria. A higher load efficiency indicates that wear on the outer peripheral surface of the inner cable and the inner peripheral surface of the outer casing is suppressed. (Initial load efficiency) A: 91% or more B: Less than 91% (Load efficiency after 1 million cycles) A: 88% or more B: Less than 88%

[0058] <Stick-slip test> The presence or absence of stick-slip was confirmed when the inner cable 20 was reciprocated 1 million times under the conditions of the durability test. Specifically, the operating load F1 derived from the static friction coefficient required for the inner cable 20 to start moving from a stopped state, and the operating load F2 derived from the kinetic friction coefficient required for moving the inner cable 20 at a constant speed were each monitored, and if F1 / F2 was not 0.005 or more, it was determined that stick-slip had not occurred, and cases with stick-slip were displayed as "+" and cases without stick-slip were displayed as "-".

[0059] <Long-term oil separation test> In accordance with JIS K 2220 11, the degree of oil separation (mass%) of each test grease composition was measured after standing at 100°C for 1000 hours.

[0060] [Table 1]

[0061] [Table 2]

[0062] The notes in Table 2 are as follows: (Note 1) R150×180°: The control cable 10 is routed so that the bending radius R is 150 mm and the total bending angle is 180°. Here, the bending radius R is “R” shown in FIG. 2.

[0063] The results in Table 1 show that a control cable in which the grease composition according to this embodiment, which contains silicone base oil, amino-modified silicone, thickener, polytetrafluoroethylene (PTFE) powder, and a specified amount of tungsten disulfide, is applied to the outer surface of the inner cable and the inner surface of the outer casing, can significantly suppress stick-slip and wear during long-term use. [Explanation of symbols]

[0064] 10 control cable, 20 inner cable, 21 shaft, 23 strand, 25 strand core wire, 27 strand side wire, 30 outer casing, 31 liner, 33 shield, 35 coating layer, 41 clearance, 91 thermostatic chamber, 93 push-pull force measuring instrument, 95 spring

Claims

1. A grease composition for a control cable, comprising: a silicone base oil; an amino-modified silicone; a thickener; a layered compound powder containing tungsten disulfide; and a polytetrafluoroethylene powder, A grease composition having a tungsten disulfide content of 0.1 to 5.0 mass %.

2. 2. The grease composition according to claim 1, wherein a total content of said layered compound powder and said polytetrafluoroethylene powder is 5 to 30 parts by mass per 100 parts by mass of said silicone base oil.

3. 3. The grease composition according to claim 1, wherein the content of the amino-modified silicone is 1.0 to 13 parts by mass per 100 parts by mass of the silicone base oil.

4. The grease composition according to any one of claims 1 to 3, wherein the tungsten disulfide has a volume average particle diameter of less than 9.0 µm.

5. The kinetic viscosity of the silicone base oil at 25° C. is 50 to 2000 mm 2 The grease composition according to any one of claims 1 to 4, wherein

6. The grease composition according to any one of claims 1 to 5, wherein the amino-modified silicone is a silicone whose side chain is modified with an amino group.

7. The grease composition according to any one of claims 1 to 6, wherein the compound powder having a layered structure consists solely of the tungsten disulfide.

8. The grease composition according to any one of claims 1 to 7, wherein the thickener is a lithium soap-based thickener.

9. The grease composition according to any one of claims 1 to 8, wherein the content of the silicone base oil is 50 to 89 mass%.

10. The grease composition according to any one of claims 1 to 9, wherein the content of the thickener is 5 to 44 mass%.

11. A control cable comprising an inner cable and an outer casing, the inner casing being coated with the grease composition according to any one of claims 1 to 10.

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