A pump, comprising: an accommodating housing which forms a cup-shaped accommodating space comprising an end-facing wall and a circumferential wall; a pump insert which is arranged in the accommodating space, wherein the pump insert comprises: - a rotor; - a first housing part and a second housing part, between which the rotor is arranged such that it can be rotated about a rotational axis and relative to the first and second housing part (2, 3); - a stroke ring which surrounds the rotor and is arranged between the first housing part and the second housing part, wherein a spring which flexes along or in the direction of the rotational axis is arranged between the accommodating housing and the second housing part, wherein the spring comprises a spring structure which is made of metal, in particular steel, and which imbues the spring with its essential spring characteristics along or in the direction of the rotational axis, and wherein the spring is supported on the accommodating housing in a region which is arranged in axial alignment with the stroke ring in the direction of the rotational axis, and is supported towards the second housing part in a region which is arranged in axial alignment with the stroke ring in the direction of the rotational axis, and thus presses the second housing part against the stroke ring, characterised by at least one positioning element which positions the second housing part with respect to its angular position about the rotational axis relative to the first housing part, wherein the spring is fastened to the at least one positioning element or the second housing part. an accommodating housing which forms a cup-shaped accommodating space comprising an end-facing wall and a circumferential wall; a pump insert which is arranged in the accommodating space, wherein the pump insert comprises: - a rotor; - a first housing part and a second housing part, between which the rotor is arranged such that it can be rotated about a rotational axis and relative to the first and second housing part (2, 3); - a stroke ring which surrounds the rotor and is arranged between the first housing part and the second housing part, - a rotor; - a first housing part and a second housing part, between which the rotor is arranged such that it can be rotated about a rotational axis and relative to the first and second housing part (2, 3); - a stroke ring which surrounds the rotor and is arranged between the first housing part and the second housing part, wherein a spring which flexes along or in the direction of the rotational axis is arranged between the accommodating housing and the second housing part, wherein the spring comprises a spring structure which is made of metal, in particular steel, and which imbues the spring with its essential spring characteristics along or in the direction of the rotational axis, and wherein the spring is supported on the accommodating housing in a region which is arranged in axial alignment with the stroke ring in the direction of the rotational axis, and is supported towards the second housing part in a region which is arranged in axial alignment with the stroke ring in the direction of the rotational axis, and thus presses the second housing part against the stroke ring, characterised by at least one positioning element which positions the second housing part with respect to its angular position about the rotational axis relative to the first housing part, wherein the spring is fastened to the at least one positioning element or the second housing part.