Hazrat Abu Ayub Ansari’s name was Hazrat Khalid (ra) and his father was Zaid bin Kulayb.
(Ali Ibn al-Athir, Usd al-Ghabah fi Ma’rifat al-Sahabah, Vol. 6, Hazrat Abu Ayub al-Ansari [Beirut, Lebanon: Dar al-Kutub al-‘Ilmiyyah, 2003], 22)
He is known by his name as well as his title. Hazrat Abu Ayub Ansari (ra) belonged to the Banu Najjar branch of the Ansar tribe of Khazraj.