JPS629159B2 - - Google Patents

Description

[Detailed description of the invention]

[Field of Application of the Invention] The present invention relates to a grease composition for a cork friction plate of an electromagnetic clutch motor and an electromagnetic clutch motor using the same, and particularly relates to a grease composition for a cork friction plate suitable for industrial sewing machines and an electromagnetic clutch motor. . [Background of the Invention] Recently, the sewing industry has been actively promoting rationalization and labor saving of sewing operations. For this reason,
As drive motors for industrial sewing machines, electromagnetic clutches and automatic stop clutch motors with electromagnetic brakes (hereinafter referred to as electromagnetic clutch motors) have come to be widely used, making it extremely easy to operate the sewing machines. An electromagnetic clutch motor consists of an induction motor, an electromagnetic clutch, and an electromagnetic brake. Each of the electromagnetic clutch and electromagnetic brake mechanisms is equipped with an electromagnetic stator and a movable plate that slides in the axial direction on the spline of the clutch shaft, and each movable plate is equipped with a cork friction plate, so that the two movable plates are interlocked. connected. One cork friction plate faces the friction disc on the induction motor side (hereinafter referred to as the clutch disc), and the other cork friction plate faces the friction disc on the inertial body (pulley) side (hereinafter referred to as the brake disc). ing. The method of operating the electromagnetic clutch motor having the above structure is well known from Japanese Patent Application Laid-Open No. 52-94960, etc., and will be briefly explained as follows. The rotor of an induction motor is constantly rotating, and a flywheel fixed to the end of the shaft stores rotational energy. When the clutch winding is energized, a magnetic circuit is generated and the electromagnetic stator with the clutch winding is attracted to the clutch disk. The clutch disk is constantly rotated by an induction motor, and the movable plate on the clutch winding side comes into contact with this disk due to the suction, so rotational motion is transmitted to the pulley side via the clutch disk, cork friction plate, and movable plate. , the pulley rotates. 2
The cork friction plates are axially interlocked so that when they are in contact with the clutch disk, they are separate from the brake disk. Then, for stopping, the brake winding is energized, a magnetic circuit is generated, and the movable plate with cork friction plate is attracted to the brake disc together with the electromagnetic stator with the brake winding. 2
Since the cork friction plate of the plate is interlocked in the axial direction, it separates from the clutch disk at the same time as it contacts the brake disk. Therefore, the rotational movement on the clutch disk side is no longer transmitted to the pulley side, and at the same time, the inertial rotational movement on the pulley side is stopped by contact between the cork friction plate and the brake disk. In this way, industrial sewing machines are started and stopped by connecting an electromagnetic stator with a clutch winding and a brake winding, and a movable plate fixed to two cork friction plates that slide in the axial direction on the spline of the clutch shaft. It is carried out by. Cork friction plates are used as this type of lining material because industrial sewing machines are started and stopped frequently, and the noise generated when they are connected and the unpleasant odor from the friction plates due to frictional heat from sliding are objectionable. but,
Cork alone has excellent braking performance for sewing machines, but its wear resistance is poor. For this purpose, methods include impregnating the cork friction plate with lubricating oil, applying a lubricant that forms a film of solid lubricant such as graphite or molybdenum disulfide, or grease containing graphite or molybdenum disulfide on the surface of the cork plate. Another known method is to impregnate cork with lubricating oil and apply a lubricant or grease that forms a film of graphite, molybdenum disulfide, etc. on the surface. Using these methods, the braking performance and wear resistance of cork friction plates can be improved considerably, but none are fully satisfactory. All of the above methods are aimed at forming a lubricating film on the surface of the cork friction plate, preventing direct contact between each disc plate (friction disk) and the cork friction plate, and reducing wear on the cork friction plate. be. This lubricating film has a considerably high temperature atmosphere due to the heat of sliding friction, so the oil impregnated in the cork friction plate and the lubricant on the surface are oxidized and deteriorated. As oxidative deterioration accelerates, lubricity is lost, and as the temperature rises and the lubricating film wears out, cork friction plates rapidly wear out. For a cork friction plate to withstand long-term use, the lubricant applied to the surface of the cork friction plate must have excellent heat resistance, adhesion, and appropriate lubricity. Moreover, since the friction plate involves rotational movement, there is a risk that the grease will fly away due to centrifugal force during the rotational movement. [Object of the Invention] The object of the present invention is to provide a grease composition for a cork friction plate of an electromagnetic clutch motor, which greatly improves the wear resistance of the cork friction plate and extends its life, and has excellent control performance. To provide an electromagnetic clutch motor using an electromagnetic clutch motor. [Summary of the Invention] The lubricating grease composition for cork friction materials according to the present invention has the following configuration. (a) A thickening agent selected from lithium stearate and lithium 12-hydroxystearate. (b) Base oil with a viscosity of 30 to 1000cst at 37.8℃. (c) Solid lubricating oil selected from graphite and molybdenum disulfide. (d) Antioxidants or corrosion inhibitors. At least these components (a) to (d) are mixed and applied to the cork friction plate. Component (B) has the function of making the lubricant of component (C) adhere to the cork board. However, if only components (B) and (C) are used, there is a risk of oxidative deterioration as mentioned above, so component (D) is necessary, and furthermore, component (A) is required to prevent these components from volatilizing due to centrifugal force. is necessary. Component (A) itself is usually in powder form, but when heated to around 200°C and cooled, it becomes spongy, and the base oil is wrapped in this sponge, making it difficult to volatilize. In terms of blending amount, component (a) is 1 to 20% by weight, and component (b) is 1 to 20% by weight.
is preferably 70 to 98% by weight. Polyalkylene glycol is used as component (b), but from the viewpoint of coatability of the grease layer and workability, it is preferable to use polyalkylene glycol in the range of 30 to 1000 cst at 37.8°C. Polyalkylene glycol, which is a component of the composition of the present invention, is also called polyglycol or polyether synthetic oil, and contains ethylene oxide,
It is an oligomer obtained by addition polymerization of alkylene oxide such as propylene oxide, and can be represented by the following general formula. R ₁ —[O—(R ₂ O)m—R ₃ ]n (1) In the formula, R ₁ and R ₃ are hydrogen, an alkyl group, an alkenyl group, an acyl group, a benzyl group, or an allyl group, and are the same or May be different. R ₂ is carbon number 2
~4 alkylene group. m is a number from 2 to 500, and n is a number from 1 to 6. Note that polyalkylene glycol has better adhesion to cork than other lubricating oils, such as mineral oil and neopentyl polyether ester, and is therefore effective in preventing grease from scattering. Furthermore, component (d) is one of the components that contributes to improving the thermal stability of grease and preventing corrosion, and amine-based or phenol-based components are used, and the blending amount is preferably 0.5 to 5% by weight. Of course, an antioxidant and a corrosion inhibitor may be used together. If the amount of antioxidant is less than 0.1% by weight, the antioxidant effect will be severely reduced. Moreover, if it exceeds 5% by weight, the effect of preventing oxidative deterioration is not expected to be that great. In other cases, the antioxidant effect may be reduced. In addition, examples of amine-based antioxidants include M-phenyl-a-naphthylamine, di-secondary butylparaphenylenediamine, and examples of phenolic antioxidants such as 2.6
- ditertiarybutyl-4-methylphenol, 4,4'-methylenebis(2,6-ditertiarybutylphenol), etc. It is desirable to use the corrosion inhibitor in a range of 0.05 to 4% by weight. For example, zinc dialkyl dithiophosphates and the like have insufficient anticorrosive effects when less than 0.05% by weight. Moreover, if it exceeds 4% by weight, corrosion protection cannot be expected to be that great. A solid lubricant, that is, a self-lubricating substance such as graphite or molybdenum disulfide, is added as component (c) to the grease consisting of the above-mentioned structural components. The amount of solid lubricant mixed with 100% of grease is preferably in the range of 5 to 50% by weight. If the amount of solid lubricant mixed is less than 5% by weight, the film of solid lubricant that adheres to the cork friction plate will be very thin, making it difficult to use from the viewpoint of wear resistance of the cork friction plate.
Furthermore, if the amount of the solid lubricant mixed exceeds 50% by weight, the lubrication effect of the solid lubricant will not be so good, and the grease will become hard and difficult to apply to the cork wear plate. It is also possible to mix a thermosetting powder resin in an amount of 1 to 20% by weight as an adhesion enhancer for the solid lubricant adhered to the cork friction plate. Examples of thermosetting powder resin include phenolic resin (HP-
209NSL (manufactured by Hitachi Chemical). If it is less than 1% by weight, adhesion of the solid lubricant is insufficient. Also, 20
If it exceeds % by weight, it will adhere uniformly to the surface of the cork friction plate, and the oil impregnated in the cork will not be able to penetrate into the grease, which may lead to premature wear of the grease coating. The lining grease made of the above components can extend the wear resistance of the cork friction plate and can greatly improve the braking performance of the sewing machine. Furthermore, the grease of the present invention can be used not only as a lubricant for cork friction plates but also as a lubricant for splines of electromagnetic clutches and electromagnetic brakes other than cork friction plates. The electromagnetic clutch motor of the present invention is equipped with an induction motor, an electromagnetic clutch, and an electromagnetic brake, and forms a lubricating film on the surface of a cork friction plate fixed to a movable plate that slides on a clutch shaft. It is equipped with a mechanism in which the plate comes into contact with the friction disk, and is characterized in that the lubricating film is formed from the above-mentioned grease composition. [Examples of the Invention] Next, the present invention will be explained in more detail with reference to Examples. In addition, in order to clarify the advantages of the present invention, conventional grease was described as a comparison. The grease was manufactured using the following method. That is, lithium stearate or lithium 12-hydroxystearate was used as the thickening agent, and polyalkylene glycol was used as the base oil. An antioxidant, N-funyl-α-naphthylamine, a corrosion inhibitor, and zinc dialkyl dithiophosphate are added to half the required amount of base oil and dissolved by heating. When lithium stearate is used as a thickening agent, the temperature of the base oil in which antioxidants and corrosion inhibitors are dissolved is maintained at 1.60℃, and when lithium 12-hydroxystearate is used as a thickening agent, the temperature is maintained at 180℃. . Meanwhile, the required thickening agent is mixed with the remaining half of the base oil, heated to 200 to 220°C while stirring to dissolve, and rapidly cooled to 160 to 180°C. After maintaining this temperature for about 2 hours, the base oil containing the above-mentioned additives is added, stirred, and gradually cooled to room temperature. The solid lubricant and powdered phenolic resin are mixed in the required amounts and finished in a cylinder. In Examples 1 to 12, lithium stearate was used as the thickening agent, and Table 1 shows the composition of the constituent raw materials, that is, the composition of the lining grease. Further, Examples 13 to 24 are cases in which lithium 12-hydroxystearate is used as a thickening agent, and Table 2 shows the constituent raw materials in this case, that is, the composition of the friction material grease composition.

【table】

[Table] The general properties of the grease compositions of Examples 1 to 12 and 13 to 24, as well as the results of tests on the friction coefficient and durability of the friction plates that are applied to cork friction materials and are related to braking performance, are shown in the third table. It is shown in Table and Table 4. The friction coefficient was measured using a pin-disk friction tester under conditions of a surface pressure of 2.05 kg/cm ² and a sliding speed of 0.9 m/s. In addition, the durability of the cork friction plate is determined by the operating time until the grease applied to the surface of the cork friction plate is consumed under the conditions of a surface pressure of 0.5 kg/cm ² and a sliding speed of 13 m/s due to continuous sliding friction. evaluated. For comparison, the general properties of conventional greases are shown in Table 5.

【table】

【table】

【table】

【table】

〔Effect of the invention〕

Therefore, by using the grease for friction materials according to the present invention, the braking performance and durability of clutches and brakes can be greatly improved.

Claims (1)

[Claims] 1. (a) a thickening agent selected from lithium stearate and lithium 12-hydroxystearate, (b) polyalkylene glycol, (c) a solid lubricant selected from graphite and molybdenum disulfide, and (d) a grease composition for a cork friction plate of an electromagnetic clutch motor, which is characterized by containing an oxidation or corrosion inhibitor. 2.Equipped with an induction motor, an electromagnetic clutch, and an electromagnetic brake, a lubricant film is formed on the surface of a cork friction plate fixed to a movable plate that slides on the clutch shaft, and the cork friction plate contacts the friction disk through the lubricant film. In the electromagnetic clutch motor equipped with a device for 1) An electromagnetic clutch motor characterized by being made of a mixture of a solid lubricant selected from graphite and molybdenum disulfide, and (d) an oxidation or corrosion inhibitor.