JP2008075036A - Lubricating composition for chuck sliding part - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lubricating composition for a chuck sliding part having improved frictional properties and durability which enable securing the improvement on the gripping force and the stability of a chuck. <P>SOLUTION: The lubricating composition for a chuck sliding part comprises a grease composed of a base oil and a thickening agent and an inorganic powder which accounts for 15-65 wt.% of the total amount of the grease and the inorganic powder. The inorganic powder which is used has a primary particle diameter or an average particle diameter of about 0.1-50 μm, preferably about 0.5-20 μm (provided that when the inorganic powder is silicon oxide, the average particle diameter is about 1-50 nm, preferably 5-40 nm). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a lubricating composition for a chuck sliding part. More specifically, the present invention relates to a lubricating composition for a sliding part of a chuck, which has improved friction characteristics and durability for ensuring improvement in chucking force and stability.

  The chuck is a kind of chucking jig and is one of the most common and important components in a machine tool. There are manual operation, hydraulic operation, pneumatic operation, electric operation, etc. as the chuck operation method, and there are wedge type, cam lever type, crank type, draw down type, scroll type, etc. A wedge shape is often used because of its self-locking and inner and outer diameter chucks.

  Conventionally, grease has been used for machine tool chuck sliding parts. Generally, general-purpose grease using mineral oil as the base oil and lithium soap as the thickener is used as the grease for the chuck. .

Also, chucks with keys, chucks without keys, all types of collets, quick release chucks, tap mounting devices, nuts and torque increasing devices for attaching saw blades or abrasive discs to drive spindles, devices or mechanisms for attaching tools with drive members, etc. A solid thin film lubricant, preferably applied as a coating, is used on the main frictional engagement components of the tool holding device of the present invention, which consists of a binder and a pigment and is carried by the binder The most common combination of particulate pigments is said to be 10% graphite and 90% molybdenum disulfide.
Japanese National Patent Publication No. 11-506704

  Until now, grease with resistance to cooling fluid and cutting fluid has been listed as a necessary characteristic, and grease that satisfies those characteristics has been used. For this reason, there is a demand for powerful grasping of the workpiece and stabilization of the grasping force. For this reason, the grasping force of the chuck is an important factor, but the present situation is that it cannot respond to such a request due to the problem of a decrease in grasping force.

Conventionally, as shown in the following Patent Documents 2 to 3, although inventions relating to the shape of the chuck jaws and the weight reduction of the jaws have been seen, the relationship between the gripping force and the applied grease has not been studied.
Japanese Patent No. 2,646,076 Japanese Patent No. 2,579,750

  The chuck grasps about the grease by sliding between the master jaw and the chuck body, and the smaller the frictional force of the sliding portion, the smaller the force can be grasped. However, the conventional general-purpose grease has a problem that improvement in grasping force and stability cannot be expected due to a large frictional force.

  An object of the present invention is to provide a lubricating composition for a sliding part of a chuck that has improved friction characteristics and durability that can improve the gripping force and stability of the chuck.

  The object of the present invention is achieved by a lubricating composition for a sliding part of a chuck, in which an inorganic powder is contained in a grease comprising a base oil and a thickener in a proportion of 15 to 65% by weight in the total amount of the grease. The The inorganic powder has a primary particle size or average particle size of about 0.1 to 50 μm, preferably about 0.5 to 20 μm (however, in the case of silicon oxide, the average particle size is about 1 to 50 nm, preferably about 5 to 40 nm. ) Is used.

  The lubricating composition according to the present invention includes an inorganic powder in grease, and when this is applied to a chuck sliding portion, the friction characteristic indicated by the friction coefficient and the durability indicated by the wear scar diameter of the test piece disk. As a result, a large gripping force can be given to the various machine tool chucks as described above, the gripping force is constant, stick-slip is difficult to occur, tribo damage is difficult to occur, cooling There is an effect that resistance to the fluid and the cutting fluid is improved.

  Base oils include, for example, paraffinic and naphthenic mineral oils, synthetic hydrocarbon oils such as poly-α-olefins, ethylene / α-olefin co-oligomers, polybutenes or their hydrides, polyol esters, dibasic acid esters And ester-based synthetic oils such as aromatic polycarboxylic acid esters, phosphoric acid esters, phosphite esters, and carbonic acid esters, and ether-based synthetic oils such as alkyl diphenyl ether and polypropylene glycol.

The properties of these various base oils are not particularly limited and may be appropriately selected depending on the use conditions. In general, the kinematic viscosity (40 ° C.) is about ^{2 to} 1000 mm ² / sec, preferably about 5 to 500 mm ^2. / Sec is used. Using a base oil with a kinematic viscosity lower than this may cause a decrease in life such as an increase in evaporation loss or a decrease in oil film strength, and may cause wear and seizure. And there is a possibility of causing a problem that the torque becomes large, such as an increase in viscous resistance.

  Thickeners include soaps such as lithium soaps, lithium complex soaps, calcium soaps, calcium complex soaps, barium soaps, barium complex soaps, aluminum soaps, aluminum complex soaps or urea compounds. Used.

  As the inorganic powder, at least one kind of powder such as a silicon compound such as silicon nitride and silicon oxide, a metal phosphate such as calcium phosphate and zinc phosphate, and a metal oxide such as zinc oxide and magnesium oxide is used. . These inorganic powders have a primary particle size or average particle size of about 0.1 to 50 μm, preferably about 0.5 to 20 μm. However, for silicon oxide, about 1 to 50 nm, preferably about 5 to The one with 40 nm is used. When using an inorganic powder having a particle size smaller than this, there is a problem in durability. On the other hand, if an inorganic powder having a particle size larger than this is used, the powder particles are not smoothly supplied to the lubricated surface, so that the desired effect is obtained. I can't get it.

  These inorganic powders are used in a ratio of about 15 to 65% by weight, preferably about 25 to 55% by weight, based on the total amount of the base oil and the thickener. If the addition ratio of the inorganic powder is less than this, the ability of the added inorganic powder is not exhibited, and a reduction in the friction coefficient cannot be expected. On the other hand, if the inorganic powder is used at an addition ratio higher than this, the composition becomes too hard. Moreover, the oil separation becomes large and it becomes impossible to make grease.

  Of the remaining grease of about 85-35%, preferably about 75-45%, the base oil is about 99.9-60%, preferably about 95-70%, and the thickener is about 0.1%. Each is used in a proportion of -40% by weight, preferably about 5-30% by weight.

  In the composition, other additives such as antioxidants, rust inhibitors, corrosion inhibitors, extreme pressure agents, oiliness agents, viscosity index improvers, etc. that have been added to conventional lubricants are added as necessary. can do. Examples of the antioxidant include phenolic antioxidants such as 2,6-ditertiarybutyl-4-methylphenol and 4,4′-methylenebis (2,6-ditertiarybutylphenol), alkyldiphenylamine, Examples include amine-based antioxidants such as phenylamine, phenyl-α-naphthylamine, phenothiazine, alkylated phenyl-α-naphthylamine, and alkylated phenothiazine, and phosphoric acid-based antioxidants and sulfur-based antioxidants.

  Examples of the rust preventive agent include fatty acids, fatty acid amines, alkyl sulfonic acid metal salts, alkyl sulfonic acid amine salts, oxidized paraffins, polyoxyethylene alkyl ethers, and the like, and corrosion inhibitors include, for example, benzotriazole and benzimidazole. , Thiadiazole and the like.

  Examples of extreme pressure agents include phosphorous compounds such as phosphate esters, phosphite esters, and phosphate ester amine salts, sulfur compounds such as sulfides and disulfides, dialkyldithiophosphate metal salts, and dialkyldithiocarbamic acid metal salts. And sulfur-based compound metal salts, chlorinated paraffin, chlorinated diphenyl and other chlorinated compounds.

  Examples of the oily agent include fatty acids or esters thereof, higher alcohols, polyhydric alcohols or esters thereof, aliphatic amines, fatty acid monoglycerides, montan wax, amide waxes, and the like. Examples of other solid lubricants include molybdenum disulfide, graphite, boron nitride, and silane nitride.

  Examples of the viscosity index improver include polymethacrylate, ethylene-propylene copolymer, polyisobutylene, polyalkylstyrene, styrene-isoprene copolymer hydride, and the like.

  The composition is prepared by a method of adding a predetermined amount of base oil, thickener, inorganic powder and other necessary additives and kneading sufficiently with a three-roll or high-pressure homogenizer.

  Next, effects of the present invention will be described with respect to examples.

Examples 1-6, Comparative Examples 1-6
Base oil A: Mineral oil (40 ° C kinematic viscosity 30mm ² / sec)
〃 B: Poly α-olefin oil (40 ° C kinematic viscosity 400mm ² / sec)
〃 C: Polyalkylene glycol oil (40 ° C kinematic viscosity 400mm ² / sec)
Thickener A: Li-based soap 〃 B: Li-based composite soap 〃 C: Ba-based composite soap 〃 D: Ca-based composite soap Inorganic powder A: Zinc phosphate (primary particle size 3μm)
〃 B: Zinc oxide (average particle size 2μm)
〃 C: Silicon oxide (average particle size 14nm)
〃 D: MoS ₂ (average particle size 10μm)
Antioxidant: Phenylnaphthylamine

Lubricating composition comprising the above base oil, thickener, inorganic powder and antioxidant (used in common by 2 parts by weight) is a component of the apparatus (SRV tester) whose main parts are shown in FIG. The durability was evaluated by measuring the wear coefficient from the friction force generated between the cylinder 1 and the disk 2 and measuring the friction coefficient generated during the test under the following test conditions. . The measurement results obtained are shown in the following table.
(Test conditions)
Upper test piece: 100CR6 cylinder (15mm diameter, 22mm length)
Lower specimen: 100CR6 disc (24mm diameter, 7.9mm length)
Test load: 200N
Sliding distance: 0.5mm
Frequency: 50Hz
Test temperature: 50 ℃
Test time: 60 minutes
table
Base oil thickener inorganic powder wear
Example Type Weight part type Weight part type Weight part coefficient Depth (μm)
Example 1 A 65 A 5 A 28 0.19 0.5
〃 2 A 40 D 10 A 28 0.15 0.4
B 20
３ 3 A 35 C 15 A 20 0.15 0.4
B 28
４ 4 A 35 D 10 A 25 0.14 0.3
B 20
C 8
５ 5 B 50 C 20 B 28 0.18 0.5
Ｃ 6 C 50 A 15 A 33 0.18 0.5
Comparative Example 1 A 83 A 15 − −> 0.50 2.1
〃 2 A 78 A 10 D 10 0.38 1.2
〃 3 A 75 B 20 C 3> 0.50 2.2
４ 4 A 70 D 25 A 3> 0.50 1.9
５ 5 B 65 C 30 B 3 0.45 1.7
Ｃ 6 C 66 C 28 A 4 0.43 1.8

It is the schematic of the SRV testing machine used for the measurement.

Explanation of symbols

1 cylinder 2 disc

Claims (3)

  A lubricant composition for a sliding part of a chuck, wherein inorganic grease is contained in a grease comprising a base oil and a thickener at a ratio of 15 to 65% by weight in the total amount of the grease.   The lubricating composition for a chuck sliding portion according to claim 1, wherein the inorganic powder is at least one of a silicon compound, a metal phosphate, and a metal oxide.   The lubricating composition for a chuck sliding portion according to claim 1 or 2, wherein an inorganic powder having a primary particle size or an average particle size of 0.1 to 50 µm (however, 1 to 50 nm for silicon oxide) is used.

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