This volume explains the energy absorbed and accumulated in springs.

(a)Absorbed and accumulated energy in a spring with linear characteristics

	-	When you apply a load on the spring, deflection (deformation) occurs in accordance with Hooke's law. (See [Fig.1].) When you quickly release a load from this condition, the spring will be restored to its original condition by the oscillating motion. This means that energy by deflection is accumulated in the spring while the load is being applied.
	-	The amount of energy accumulated in this spring can be expressed in the following formula: Energy accumulated in the spring U = k · δ2 / 2    k:Spring constant  δ:Deflection This formula is equivalent to the area of the triangle OAB shown in [Fig.1].
	-	If the area of this triangle OAB in [Fig.1] is the energy storage capacity of a spring, the following is true: * When the deflection increases, the energy accumulation increases for the same springs. * For different springs, if you increase the amount of deflection, it results in a substantial amount of energy storage capacity even when the spring constant is small. This principle is applied to shock-absorbing dampers for precision equipment and MechaLock ([Fig.2]).

(b)Absorbed and accumulated energy in a spring with non-linear characteristics

	-	Some of the spring structures absorb and accumulate the energy generated during spring deflection.
	-	A ring spring ([Fig.3]) has a structure consisting of inner rings and outer rings with a conical surface alternately stacked. When a pressure load is applied in the axial direction, the outer rings expand and the inner rings contract. At that time, friction occurs on the conical surface of inner and outer rings. Since this friction causes a part of the deflection energy to be absorbed, ring springs are utilized for shock absorber and buffer equipment. (See [Fig.4].)
	-	In the case of [Fig.4], the absorbed energy at a release of the deflection is equal to the area enclosed within the load-deflection curve shown in [Fig.4].