JP2769713B2 - Damping material - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration damping material used for a brush of a small motor used for audio video, office automation equipment and the like.

[Conventional technology]

In general, the brush of a small motor is in sliding contact with the outer periphery of a cylindrical commutator so that current flows between the rotor and an external circuit. In such a brush, as the commutator rotates,
Since the contact portion vibrates and generates abnormal noise, and sparks occur due to the chattering phenomenon, some measures have been taken to prevent vibration. For example, as shown in FIGS. 2 and 3, a double-sided tape-shaped adhesive material 2
And a viscoelastic material 3 made of a rubber elastic piece or the like are laminated. In the figure, A is a commutator. The pressure-sensitive adhesive material 2 in the form of a double-sided pressure-sensitive adhesive tape is also referred to as a pressure-sensitive adhesive material, which is easily adhered with a light pressure such as a finger pressure, and is made of an acrylic or rubber-based solvent-type adhesive material. And this adhesive material 2 itself also has considerable vibration damping properties. The viscoelastic material 3 laminated on the adhesive material 2 includes
Vulcanized rubber such as butyl rubber, chlorosulfonated polyethylene rubber, fluorine rubber, chloroprene rubber and the like, and cured resins such as urethane elastomer and urethane foam are exemplified. This viscoelastic material 3 has a glass transition point near the glass transition point.
By converting vibration energy into heat energy,
It exhibits high damping (damping) and is the core of damping materials.

[Problems to be solved by the invention]

The vibration damping material 4 as described above is made by sticking an adhesive material on one side of a sheet-like viscoelastic material and cutting the adhesive material to a set size with a cutter. 1 and is attached to the brush body 1. However, since the viscoelastic material 3 made of the rubber elastic piece has high adhesiveness, the rubber adheres to the cutter blade at the time of cutting, so that the cutting cannot be performed or the dimensional accuracy of the vibration damping material is deteriorated. Later, there are problems such as the adjacent cut surfaces sticking to each other, making it difficult to separate them, and, when assembled in the motor, dust in the air adheres to the cut surface, resulting in defective contact of the motor.

The present invention has been made in view of such circumstances,
It is an object of the present invention to provide a vibration damping material that has good dimensional accuracy, that is easy to separate after cutting, and that does not cause a motor contact failure due to adhesion of dust by reducing adhesiveness.

[Means for solving the problem]

In order to achieve the above object, a vibration damping material of the present invention is a vibration damping material comprising a viscoelastic material and an adhesive material for sticking the viscoelastic material to a brush surface of a motor brush, While constituting the base material of the viscoelastic material with an elastomer,
The structure is such that fine and solid glass spheres are distributed in the base material.

[Action]

That is, in the vibration damping material of the present invention, fine and solid glass spheres are distributed in the elastomer constituting the base material of the viscoelastic material. Therefore, the distributed glass spheres are exposed on the cut surface, and the adhesiveness of the cut surface is reduced, and at the time of cutting, rubber is adhered to the cutter blade, the cut surfaces are adhered to each other, or incorporated into the motor. In this case, dust in the air does not adhere to the cut surface.
As a result, the dimensional accuracy of the vibration damping material is improved, and the vibration damping materials after cutting can be easily separated from each other.
The contact failure of the motor due to the adhesion of dust to the cut surface of the damping material does not occur. Also, because the glass sphere is solid,
If it breaks when it is cut or used as a vibration damping material, it will be of high quality without any break.

Next, the present invention will be described in detail based on embodiments.

〔Example〕

FIG. 1 shows a state in which a damping material 5 according to one embodiment of the present invention is adhered to the upper surface of a plate-like brush body 6. That is, the vibration damping material 5 is made of a double-sided tape-shaped adhesive material 7,
A viscoelastic material 9 in which glass spheres 8 having a particle size of 50 μm are distributed is laminated, and the thickness of the viscoelastic material 9 is set to 1 mm. It is set to about 20 parts for 100 parts by weight (hereinafter abbreviated as "part"). As the adhesive material 7, an acrylic or rubber-based solvent-type adhesive material is used similarly to the adhesive material 2 used for the vibration damping material 4 shown in FIG. As the base material, an elastomer containing butyl rubber as a main component is used.

The vibration damper 5 is manufactured, for example, as follows. That is, first, as an elastomer material containing butyl rubber as a main component, with respect to 100 parts of butyl rubber,
5 parts of zinc white, 1 part of stearic acid, 1.5 parts of sulfur, T
eEDC (tellurium diethyl dithiocarbamate) 1.5
Part, 1 part MBTS (dibenzothiazyl disulfide), SR
Prepare 25 parts of F black and 5 parts of process oil, and prepare 20 parts of glass balls 8, and knead them with a kneading machine such as an open roll, a Banbury mixer, or a kneader. Next, the obtained kneaded material is formed into a sheet shape by using a calender roll, an extruder equipped with a T-die, or the like, and then press-vulcanized at a temperature of 160 ° C. for 40 minutes to form a viscoelastic material. Next, after sticking an adhesive material to one surface of the viscoelastic material, the vibration damping material 5 can be obtained by cutting the viscoelastic material into a set dimension with a cutter. Then, the vibration damping material 5 is adhered to the plate-shaped brush body 6 with the adhesive material 7 side aligned with the upper surface of the plate-shaped brush body 6.

As a result of this configuration, the cutability of the vibration damping material is improved, and the glass sphere 8
Is exposed, the adhesiveness of the cut surface is reduced, and the above-mentioned problem due to the adhesiveness of the cut surface is solved.

In addition, as the elastomer constituting the base material of the viscoelastic material 9, in addition to the butyl rubber, similarly to the viscoelastic material 3 of the conventional example, a vulcanized rubber such as chloroprene rubber or a cured resin such as a urethane elastomer may be used. it can. The particle size of the glass spheres 8 is preferably set to 500 μm or less, and the compounding ratio is preferably set to 5 to 200 parts with respect to 100 parts of the base material. Further, the thickness of the viscoelastic material 9 is preferably set to 0.5 to 1.5 mm. In the base material of the viscoelastic material 9, as fillers, inorganic substances such as calcium carbonate, clay, mica, and carbon black, process oil, plasticizer, softener, antioxidant, pigment and the like are used as required. Is added as appropriate.

In addition to the damping material 5 (Example 1), a damping material 5 (Examples 2 and 3) using an elastomer containing butyl rubber or chloroprene rubber as a main component as a base material of the viscoelastic material 9 is manufactured. , Damping material not containing glass ball 8 (conventional example 1,
2) was manufactured and their physical properties and properties were compared. The results are shown in the table below.

From the above table, it can be seen that the product of the example of the present invention has improved cutability and sticking workability and loses adhesiveness while maintaining the physical property values almost the same as those of the conventional product.

In the above table, 22 is 2-mercaptoimidazoline, TT is tetramethylthiuram disulfide, and Tb
Is the tensile strength at break, and Eb is the physical property value (measured according to JISK6301) indicating the elongation at break. In addition, as butyl rubber, Exxon butyl 268 (manufactured by Exxon Chemical)
And neoprene W (manufactured by Showa Neoprene Co., Ltd.) as the chloroprene rubber.
μm was used. In addition, as the glass sphere 8,
Solid objects must be used. Thereby, a high-quality damping material can be obtained.

〔The invention's effect〕

Since the vibration damping material of the present invention is configured as described above, the adhesiveness of the viscoelastic material is reduced, and at the time of cutting, the rubber adheres to the cutter blade, or the cut surfaces adhere to each other,
When assembled in the motor, dust in the air does not adhere. As a result, the dimensional accuracy is improved, the separation after cutting is facilitated, and furthermore, the contact failure of the motor due to the adhesion of dust does not occur. In addition, since the glass sphere is solid, if it is broken at the time of cutting or when used as a vibration damping material, the glass sphere can be of high quality without breaking.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of one embodiment of the present invention, FIG. 2 is a plan view of a conventional example, and FIG. 3 is a longitudinal sectional view thereof. 5: damping material, 6: brush body, 7: adhesive material, 8: glass ball, 9: viscoelastic material

Claims (1)

(57) [Claims] 1. A vibration damping material comprising a viscoelastic material and an adhesive material for sticking the viscoelastic material to a brush surface of a motor brush, wherein the base material of the viscoelastic material is an elastomer. And a fine and solid glass sphere distributed in the base material.