Oval cross section valve springs were first put to practical use in Japan and in the world by Murata Spring.
Conversion of the circular cross sections of general valve springs (helical compression springs) to the oval cross sections provides a variety of advantages.
Reduction of solid height enables a larger stroke of a spring. Reducing the mounting height results in decreasing the dimension of the relevant parts, which saves space and reduces the weight of the parts.
This design enables higher loads or reductions in stress without changing the dimensions of the relevant parts and the mounting height.
As a result, it is possible to design springs satisfying specifications that cannot be realized by conventional round wires (circular sections).