17-5. Torsion bar

17-5. Torsion bar		Symbol description and unit
Torsion bar spring（Torsion bar）	Screw angle:　〔 Every time〕 θ=32*M*L*(180/π)/(π*(d24-d14)*G) θ= Maximum shear stress:　〔kgf/mm2〕 τmax=16*d2*M/(π*(d24-d14)) τmax=	d1： Inner diameter　〔mm〕
		d2： Outer diameter　〔mm〕
		L： Effective length of spring　〔mm〕
		M：Torsion moment　〔kgf･mm〕
		G：Lateral modulus〔kgf/mm2〕
		Lateral modulus G The value of the(Kgf/mm2) Piano wire（SWPA,SWPB）　8000 Spring steel(SUP)　　　　　　 　8000 Oil temper wire(SWO)　8000 Stainless steel wire(SUS-WH) 7000〜7500 Stainless steel wire for springs(SUS-WP) 7000〜7500
Reference: "Machine Official Collection" (co-authored by Masaaki Oishi / Tatsuo Inami) Mechanical Design Spring Page 100 Twisted bar spring (torsion bar).