Cylindrical vibration isolating device
A cylindrical vibration isolating device having an inner cylinder, an outer cylinder surrounding the inner cylinder, an elastic leg having a pair of right and left leg portions to connect the inner cylinder and the outer cylinder and, when viewed in the axial direction of the inner cylinder, being formed in a substantially inverted V-shape while placing the inner cylinder in an intermediate position, and a mass projection being provided in the elastic leg such that the mass projection resonates in a frequency range that the elastic leg causes bending resonance. The mass projection is provided outside of an inner restraint line that is a perpendicular line passing an outermost point of an inner restrained portion that is a connected portion between the inner cylinder and the elastic leg.
1. A cylindrical vibration isolating device, comprising:
an inner cylinder defining a center point, the center point being coaxially located within the inner cylinder so as to be equally spaced from all points of a perimeter of the inner cylinder,
an outer cylinder surrounding said inner cylinder,
an elastic leg having a pair of right and left leg portions connecting said inner cylinder and said outer cylinder and, when viewed in the axial direction of the inner cylinder, forming a substantially inverted V-shape with an apex point where the left leg portion joins the right leg portion, wherein a bisecting line connects the center point of the inner cylinder and the apex point of the elastic leg,
an inner restrained portion connecting said inner cylinder and said elastic leg together,
an outer restrained portion connecting said elastic leg with said outer cylinder, and
a mass projection being provided in said elastic leg such that said mass projection resonates in a frequency range that said elastic leg causes bending resonance,
wherein said mass projection is provided radially outside of an inner restraint line, said inner restraint line passing through a radially outermost point of the inner restrained portion and being parallel to the bisecting line,
and wherein said mass projection is provided entirely radially outside of an outer parallel line such that the outer parallel line is between said mass projection and said inner restraint line, said outer parallel line extending parallel to the inner restraint line and passing through a lowermost point of the outer restrained portion.
2. The cylindrical vibration isolating device according to claim 1 , wherein a center of said mass projection is located outside of an intermediate line that is between an outer restraint line connecting an uppermost point and the lowermost point of the outer restrained portion and a tangential line to an outer periphery of said inner cylinder, extending parallel to said outer restraint line, and that extends parallel to each of said outer restraint line and said tangential line.
3. The cylindrical vibration isolating device according to claim 2 , wherein at least half or more of a surface area of said mass projection is located outside of said intermediate line.
4. The cylindrical vibration isolating device according to claim 2 , wherein said mass projection is arranged outside of said intermediate line and in an upper area of said elastic leg.
5. The cylindrical vibration isolating device according to claim 4 , wherein said mass projection is provided adjacent a cavity formed between an upper edge of said elastic leg and said outer cylinder.