Cakka: ‘wheel’, is one of the seven ‘precious possessions’ ratana of a righteous World Emperor cakkavatti ‘He who owns the Wheel,’ cf. D. 26, and symbolizes conquering progress and expanding sovereignty. From that derives the figurative expression dhamma - cakkam pavatteti, he sets rolling the Wheel of the Law’ and the name of the Buddha’s first sermon, Dhamma-cakkappavattana Sutta see: dhamma-cakka.
Another figurative meaning of C. is ‘blessing’. There are 4 such ‘auspicious wheels’ or ‘blessings’: living in a suitable locality, company of good people, meritorious acts done in the past, right inclinations A. IV, 31.
bhāva - cakka ‘wheel of existence’, or of life, is a name for ‘dependent origination’ see: paticca-samuppāda.
See The Buddhist Wheel Symbol, by T. B. Karunaratne WHEEL 137/138; The Wheel of Birth and Death, by Bhikkhu Khantipalo WHEEL 147/149