JPH0463255B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a motor with an electromagnetic clutch and brake used in industrial sewing machines, etc., and in particular, a friction material used for the clutch lining and brake lining of the electromagnetic clutch and brake. This invention relates to an electromagnetic clutch/brake movable plate that is integrated with a movable iron core that is a supporting iron core.

Construction of a conventional example and its problems First, the construction of a motor with an electromagnetic clutch and brake that uses a movable electromagnetic clutch and brake plate that integrates a friction material and a movable iron core will be described with reference to FIG.

Figure 1 shows the configuration of the main parts of a motor with an electromagnetic clutch and brake.A flywheel, which is an inertial body, has a clutch disk 2, which is one of the clutch components, fixed to one end of the rotating shaft 1 of the drive motor. wheel 3
is fixed. An end bracket 4 located opposite the flywheel 3 is connected to a clutch winding 5.
A clutch yoke 5 having a brake winding 6a
It holds a brake yoke 6 and a brake shoe 7, has a pulley 9 for taking out an output via a bearing 8, and supports a clutch shaft 11 having a sliding shaft (spline) 10 at the other end. ing. A clutch ring (movable iron core) 14 and a brake ring (movable iron core) 15 holding a clutch lining (friction material) 12 and a brake lining (friction material) 13 are movable in the axial direction on the sliding shaft 10 and rotate in the direction of rotation. They are supported so that they cannot move relative to each other, and are connected by an O-ring 16 and a coupling ring 17.

Next, the operation of the electromagnetic clutch/brake will be explained.

The rotating shaft 1 is continuously rotating, and a flywheel 3 fixed to the end of the shaft is in a state where rotational energy is stored. Therefore, when the clutch winding 5a is energized, the electromagnetic force 5b is generated, the clutch ring (movable iron core) 14 is attracted to the clutch disc 2, and the rotational power is slid through the clutch lining (friction material) 12. It is taken out to the pulley 9 through the shaft 10 and clutch shaft 11. When stopping the brake winding 6a, an electromagnetic force 6b is generated and the brake ring (movable iron core) 15 is attracted to the brake shoe 7, and the brake lining (friction material) 1
A brake shoe 7 is fixed to the sliding shaft 10 through the brake shaft 3 and to the end bracket 4 through the clutch shaft 11.
A braking force is generated between the brake and the brake.

Motors with electromagnetic clutches and brakes having the above-mentioned structure are widely used to drive industrial sewing machines that are frequently started and stopped, and motors of about 400 W are used. In particular, for a motor with an electromagnetic clutch and brake for driving a sewing machine, the clutch and brake are operated approximately 10,000 times a day, so a long-life friction material is required, and one that is quiet during operation. was desired.

Conventionally, friction materials for motors with electromagnetic clutches and brakes as described above are disclosed in U.S. Patent Nos. 3016119, 3073424, and 3231058.
As described in the specification, cork particles obtained by crushing dried cork bark having a soft cell structure are mixed with a binder such as a phenol resin, a polyurethane resin, a urea resin, or a polyvinyl acetate resin, and the mixture is heated and compressed. A soft porous material such as pressed cork or fired cork is used.

The reason why a soft porous material such as cork is used as the above-mentioned friction material is that even though cork is a natural plant product, it is chemically resistant to oils, organic acids, soaps, alkalis, salts, etc. This is because it is stable and has sufficient heat resistance for practical use as a friction material for electromagnetic clutches and brakes where the temperature of the friction surface is up to about 80°C. In addition, characteristics such as softness derived from the fine air-filled cell structure, high damping property (tan δ), and high porosity soften the hitting sound during clutch/brake operation, and other than the frictional properties, This is because it basically has the property of being a material that is difficult to squeal during clutch/brake operation.

On the other hand, if a soft porous material such as cork does not have a lubricating film on its friction surface, the coefficient of friction is likely to change due to external factors during clutch/brake operation, such as temperature and sliding speed. This makes torque transmission or braking ability unstable. Furthermore, since soft porous materials such as cork have poor heat dissipation properties, frictional heat during clutch/brake operation tends to accumulate on the friction surface, and as a result, a portion of the cork may transfer to the mating material, or In addition, abnormal wear occurs in which part of the cork falls off. In this way, when a soft porous material such as cork directly rubs against the mating material without using a lubricating film, squeal may occur during clutch/brake operation, or wear may be significantly accelerated and the friction material may deteriorate prematurely. This results in the end of life.

Therefore, when using a soft porous material such as the above-mentioned cork as a friction material, it is important to improve the friction characteristics by forming a lubricating film on the friction surface.

As a means for forming a lubricating film on the friction surface, it is effective to impregnate cork with oil or grease, such as the friction material described in US Pat. No. 3,777,864. Due to the effect of the lubricating film, it is possible to ensure a significantly stable friction coefficient with respect to temperature, surface pressure, sliding speed, etc. during clutch/brake operation, and the viscosity of the oil that forms the lubricating film can be adjusted. By doing so, it is also possible to obtain desired torque transmission and braking characteristics. Furthermore, it is known that a lubricating film exists on the friction surface, and as long as it fulfills its function, abnormal wear of the friction material can be prevented and the life of the friction material can be qualitatively extended.

However, when cork is impregnated with oil or grease, the amount of impregnation, its functional role, and the electromagnetic clutch that integrates the friction material and the movable core are important.
Nothing has been clarified regarding the features that the movable brake plate should have, and as a result, there have been drawbacks, such as the fact that the wear life of the friction material tends to fluctuate greatly.

Purpose of the Invention The present invention aims to extend the life of an electromagnetic clutch/brake movable plate that integrates a movable iron core with a friction material made of a soft porous material such as cork impregnated with oil or grease, and to extend its reliability. The purpose is to enhance sexuality.

Structure of the Invention The present invention integrates a friction material and a movable iron core, and as shown in FIG.
The order is c and d.

(a) Cork particles 1a, binder 2a, liquid lubricant 3
A friction material consisting of a.

(b) Cured film of epoxy resin solvated with liquid lubricant 3a.

(c) Cured epoxy resin film.

(d) Movable iron core.

Further, the content of the liquid lubricant 3a of the friction material a is at least 18 wt%, and the sum of the thicknesses of the cured epoxy resin films b and c is 20 μm or more.

DESCRIPTION OF THE EMBODIMENTS The friction material referred to in the present invention consists of cork particles, a binder, and a liquid lubricant. Cork particles are obtained by crushing dried cork bark, and the particle size is generally preferably 6 to 60 mesh. If the particle size is large, the content of the liquid lubricant will be insufficient, and if the particle size is small, the workability in manufacturing the friction material will be reduced. (Cork is used as a waterproofing material and cork stopper, but due to its own bark-like substance and uniform cell structure, it is extremely difficult to infiltrate liquid lubricant into the cork's own cells. exists between cork particles.) As the binder, phenolic resins, polyurethane resins, polyvinyl acetate resins, etc., which are generally used when producing pressed cork or fired cork using cork particles as a raw material, can be used. The amount of the binder varies depending on the particle size and distribution of the cork particles, but is generally 10 to 30 parts by weight per 100 parts by weight of the cork particles. If the amount of the binder is small, the binding force between the cork particles will be insufficient, and if the amount is too large, it will be difficult for the liquid lubricant to penetrate between the cork particles.
The liquid lubricant referred to in the present invention is one or a mixture of two or more natural or synthetic oils such as mineral oil, α-olefin and its copolymer, polyalkylene glycol, polyalkylene oxide, dibasic acid ester, and hindered ester. It is. Moreover, they may be added with various additives as necessary. For example, higher alcohols, ketones, ester amines or higher fatty acids, oily agents which are long chain compounds with polar groups such as metal soaps and fats and oils, antifoaming agents such as polymethylsiloxane, sulfonates, amines, organic acids or their Rust inhibitors that are organic compounds with polar groups such as salts and esters, water repellent agents such as organic silicon compounds and higher aliphatic amines, adhesives such as polyisobutylene, polymethacrylate, and aluminum soaps made of unsaturated fatty acids; Free fatty acid glycerides, alkaline earth salts and lithium salts of naphthenic acids, zinc soaps, release inhibitors such as petrolactam, graphite,
These include solid lubricants such as molybdenum disulfide polytetrafluoroethylene. The content of the liquid lubricant as described above is at least 8% by weight of the friction material.

Next, in the present invention, the cured film of epoxy resin solvated with the liquid lubricant is the uncured epoxy resin that increases the polarity of the liquid lubricant and breaks through the liquid lubricant layer to form cork particles or bonds. Refers to the film that hardens after penetrating the agent. Epoxy resins that have discovered such functions include polyglycol-type epoxy oligomers, and epoxy resin curing agents such as polyamides. It is necessary to make it an essential component of at least one of the agents.

Next, the cured epoxy resin film referred to in the present invention is one that firmly joins the movable iron core to the cured film of the epoxy resin solvated with the liquid lubricant, and there are no particular restrictions on the type of epoxy resin. Of course, the epoxy resin may have the same composition as the epoxy resin that is solvated with the liquid lubricant. Note that the formation of both epoxy resin cured films may be performed separately or simultaneously.

Furthermore, the movable iron core referred to in the present invention is a soft magnetic material, and carbon steel, which is easy to machine, is usually used.

Next, the effects of the present invention will be explained using examples.

[Abrasion of liquid lubricant and friction material]

First, 100 parts by weight of 14-35 mesh cork particles and 20 parts by weight of polyurethane resin were thoroughly mixed and then shaped to obtain pressed cork with an apparent density of about 0.5 g/cc.
This was impregnated with a liquid lubricant having a kinematic viscosity of about 80 cst at 40°C to obtain a doughnut-shaped friction material a having an outer diameter of 112 mm, an inner diameter of 69 mm, and a thickness of 4.5 mm. However, the liquid lubricant used here is based on synthetic oil (Hisodade ester), and its additives include polyisobutylene, 4,
It uses 4'-butylidene pis6.t-butyl3.methylphenol.

The content of liquid lubricant in the friction material is 0.2~
5, 8-10, 12-14, and 18-20% by weight, and liquid lubricants were separately applied from the friction surface.
Next, as epoxy resin A, 50 parts by weight of bisphenol type epoxy oligomer, 50 parts by weight of polyglycol type epoxy oligomer, and 20 parts by weight of dicyandiamide were added.
By mixing parts by weight, applying it to the anti-friction surface of the friction material at room temperature, and heating and curing it, a cured film b of the epoxy resin solvated with the liquid lubricating oil in the friction material having a film thickness of approximately 50 μm is formed. did.

Next, as epoxy resin B, 100 parts by weight of bisphenol type epoxy oligomer and 20 parts by weight of dicyandiamide were mixed, and the liquid lubricant and the above-mentioned liquid lubricant were solvated. A cured epoxy resin film c having a thickness of approximately 10 μm was provided to serve as a movable electromagnetic clutch/brake plate.

Figure 3 shows that electromagnetic clutch/brake movable plates with different amounts of liquid lubricant in the friction material are mounted on a motor with electromagnetic clutch/brake as shown in Figure 1, and the clutch/brake operation is performed for 1 sec each. FIG. 3 is a characteristic diagram showing the relationship between the number of operations and the amount of wear of the friction material when performing each operation.

As is clear from Figure 3, wear progresses rapidly in the absence of liquid lubricant on the friction surface, and when the content of liquid lubricant in the friction material is 2 to 5 wt%, it is difficult to apply liquid lubricant to the friction surface. Only the same level of wear characteristics as those of the same type can be obtained. In other words, in order to achieve the effect of impregnating a liquid lubricant into a friction material, it is generally necessary to contain 8wt% or more of liquid lubricant in the friction material, and in order to further extend the friction life of the friction material. Desirably, the content is 18 wt% or more.

FIG. 4 is a characteristic diagram showing the relationship between the amount of liquid lubricant flowing out and the liquid lubricant content in the friction material when a friction material and a movable iron core are joined to form an electromagnetic clutch/brake movable plate.

The amount of liquid lubricant flowing out is determined by inserting filter paper into the joint and tightening the friction material at an arbitrary pressure at room temperature to suppress deformation due to free expansion of the friction material during heating, and then heating it at 150℃. It was estimated based on the weight increase of the filter paper when

As is clear from FIG. 4, the amount of liquid lubricant in the friction material flowing out during the joining operation tends to increase rapidly when the liquid lubricant content in the friction material is approximately 18 wt% or more.

As mentioned above, the liquid lubricant content in the friction material is
When it is 18wt% or more, it can sometimes have an effect on the friction life, but on the other hand, it is difficult to put it to practical use as an electromagnetic clutch/brake movable plate unless technology is established to ensure sufficient bonding force with the movable iron core.

[Joining friction material and movable core]

As in the previous section, friction materials, movable iron cores, and epoxy resins A and B with different liquid lubricant contents were prepared. In order to make the film thickness of the cured epoxy resin constant, glass nonwoven fabrics with different thicknesses were prepared.

First, epoxy resins A and B are applied to the movable core, a glass non-woven fabric is laid down to control the film thickness, and the friction material is combined with the epoxy resin. was hardened and used as a movable plate for electromagnetic clutches and brakes. When the friction material of this electromagnetic clutch/brake movable plate is excavated, the material that is not bonded at all or the material that has peeled off at the interface between the cured epoxy resin film and the movable iron core is designated as X, and only the friction material is excavated. The reliability of the bonded surface was evaluated using O as the case where the cured epoxy resin film and the movable iron core were firmly bonded. On the other hand, the amount of liquid lubricant contained in the friction material flowing out was estimated when a separately prepared filter paper was used instead of the epoxy resin to serve as a movable electromagnetic clutch/brake plate.

FIGS. 5 and 6 are characteristic diagrams collectively showing the above results.

As shown in FIG. 5, when a friction material and a movable iron core are combined to form an electromagnetic clutch/brake movable plate, the amount of liquid lubricant that flows out to the joint surface side depends most on the content of the liquid lubricant. On the other hand, in the bonded state shown in Figure 6, a cured film is formed after the epoxy resin is solvated with a liquid lubricant, and a single cured film of epoxy resin exists on the movable iron core surface due to sufficient film thickness. As far as I'm concerned, it's as good as it gets.

The above bonding state can be explained in more detail as follows. Epoxy resin B, which is difficult to solvate with the liquid lubricant in the friction material, does not bond to the friction material. On the other hand, the epoxy resin A that is solvated with the liquid lubricant is bonded to the friction material. However, when the cured film of epoxy resin A that is solvated with the liquid lubricant and cured comes into contact with the movable core, the liquid lubricant penetrates through the cured film and reversely permeates into the interface between the cured film and the movable core. Incidentally, the internal mold release agent in the molding material plays a role similar to that acting on the wall surface of the mold, making it impossible to achieve a sufficient bonding state. Therefore, in such cases, sufficient bonding conditions can only be found if the liquid lubricant content in the friction material is
It is clear that the sum of the film thicknesses of the cured film of the epoxy resin solvated with the liquid lubricant and the cured film of the epoxy resin alone at a concentration of 18 to 20 wt% must be at least 20 μm or more. be.

Effects of the Invention As described above, the present invention relates to motors with electromagnetic clutches and brakes used in industrial sewing machines, etc., and is particularly applicable to clutch linings and brake linings for electromagnetic clutches and brakes for which long life is desired. can significantly extend the life of friction materials used in

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view of the main parts of a motor with an electromagnetic clutch and brake, Fig. 2 is a cross-sectional view of the main parts of a movable electromagnetic clutch and brake plate according to the present invention, and Fig. 3 shows wear of the electromagnetic clutch and brake movable plate. Characteristic diagram shown,
Figure 4 is a characteristic diagram showing the relationship between the content of liquid lubricant and the amount of outflow during welding operations, Figure 5 is a characteristic diagram showing the relationship between welding conditions and the amount of liquid lubricant outflow, and Figure 6 is FIG. 3 is a characteristic diagram showing the relationship between the bonding state and the thickness of a cured epoxy resin film. a...Friction material, b, c...Cured film of epoxy resin, d...Movable iron core.

Claims (1)

[Claims] 1 The cross-sectional configuration of the joint portion between the friction material and the movable iron core is shown from the friction material side: a: a friction material consisting of cork particles, a binder, and a liquid lubricant; b: a solvate with the liquid lubricant; An electromagnetic clutch/brake movable plate provided in this order: c: cured epoxy resin film; d: movable iron core; 2 The liquid lubricant content of friction material a is at least
18wt%, and epoxy resin cured film,
The electromagnetic clutch/brake movable plate according to claim 1, wherein the sum of film thicknesses b and c is 20 μm or more.