ROD WITH TEMPERATURE INDEPENDENT AXIAL SIZE Russian patent published in 2003 - IPC

FIELD: mechanical engineering. SUBSTANCE: invention can be used in all branches of industry for extremely precise machines, instruments and mechanisms exposed to considerable temperature fluctuations of surrounding medium. Proposed rod contains two concentrically installed bushing-intermediate one and enclosing one and rod arranged in center. According to invention, intermediate bushing is made of material featuring high linear expansion coefficient being fixed by one end on end of enclosing bushi8ng and by opposite end with end of center rod. Linear sizes of rod with temperature independent axial size are found from equation where L is temperature independent axial size of rod, mm; l₁ - is initial length of enclosing bushing, mm: l₂ - is initial length of working section of intermediate bushing, mm; l₃ is initial length of central rod, mm; α₁, α₂, α₃ are linear expansion coefficients of material of enclosing bushing, intermediate bushing and central rod, 1/oC. EFFECT: no negative action of ambient temperature onto axial base size of rod. 4 cl, 3 dwg