The utility model discloses a connecting piece, a
filter element assembly and a filter, the connecting piece comprises a hollow support and an end disc connected with one end of the support, and the support is arranged on the periphery of a
filter element in a surrounding mode and used for limiting the
filter element in the radial direction; an oil return plug is eccentrically arranged on the outer end face of the end disc and used for sealing an oil
return channel in the filter
assembly. According to the technical scheme, when the filter element is assembled, an operator can firstly install the connecting piece with the oil return plug into the filter
assembly, meanwhile, the oil return plug on the end disc also enters and seals the oil
return channel in the assembly, then the filter element is installed in the
screw cap or placed into the connecting piece, and finally the
screw cap is screwed on the assembly. When the filter element is disassembled, after the
screw cap is unscrewed, the screw cap takes out the filter element, and meanwhile, the filter element is taken out of the connecting piece. According to the scheme, the situation that the position of the oil return plug is adjusted in a rotating mode can be avoided, the filter element assembly can be installed without too much operation experience, product
machining is easy, and the requirement for deviation is low.