| 摘要 |
PROBLEM TO BE SOLVED: To clarify the concrete composition of a vibration control cushion to ensure necessary vibration control performance and prevent the damage of an outside resin material. SOLUTION: A vibration control cushion 20 made of rubber is molded on the outside of a casing cap 10 and a cover cushion 30 made of resin the material of which is polyamide resin is molded on the outside thereof. EPDM rubber in a ratio consisting of 40-48% a rubber component, 20-24 wt.% a rubber reinforcing material, and 32-28 wt.% oil or natural rubber in a ratio consisting of 40-55 wt.% a rubber component, 26-29 wt.% a rubber reinforcing material, and 10-20 wt.% oil are used as the rubber material of the vibration control cushion 20, and hardness is set to 38-48 deg. and dynamic magnification to 2-3. A free sulfur component in the rubber component is suppressed to 0.25 wt.% or less, an addition sulfur component to 0.23% or less. This constitution ensures vibration controllability against vibration of 40-250 Hz and prevents the damage of a resin material.
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