The invention relates to a connecting sealing structure of a
nozzle assembly of a
solid rocket engine. The spray
pipe expansion section is a cylindrical structure with an inner cavity in a trumpet shape, a first step, a second step and a third step are sequentially arranged on the outer surface of the spray
pipe expansion section, the spray
pipe shell is sleeved outside the spray pipe expansion section, the inner cavity of the spray pipe shell is provided with a first step groove, a second step groove and a third step groove, the first step groove and the second step groove, and the third stepis matched, a
sealant is arranged between the first step of the
nozzle expanding section and the first step groove of the
nozzle shell, the second step part of the spray pipe expansion section is provided with a concave annular installation groove, and the
retaining ring is arranged in the concave annular mounting groove and forms a thread pair with the spray pipe shell. The structure can be applied to the connection of almost all small
solid rocket engine nozzle assemblies, in particular, to address such limitations as structural space, it is desirable to withstand higher
impact and higher weatherability, the nozzle
assembly connecting structure with the problems of temperature
shock resistance performance requirement and the like provides a high reliability. the structure is simple andcompact, and the
processing technology is simple and convenient.