Operating assembly for pumps for recirculating a cooling fluid of combustion engines and recirculating pump provided with such an operating assembly
Operating assembly for a pump for recirculating a cooling fluid of a vehicle, comprising: an axially extending driven shaft ( 2 ) with a front end ( 2 a ) designed to carry the impeller ( 1 ) of a pump, at least one electromagnetic friction clutch ( 2 ), arranged between an element ( 21,21 a ) for taking up the rotational movement and the driven shaft ( 2 ), an electric drive for driving the driven shaft ( 2 ) independently of the movement take-up element, a support body ( 11;13 ) extending axially between a front part which carries the front end of the shaft ( 2 ) and a rear end which rotationally supports the movement take-up element, wherein the electric drive is axially arranged between the front end of the shaft and said movement take-up element.
1 . An operating assembly for a pump with an impeller for recirculating a cooling fluid of a combustion engine of a vehicle, comprising
a driven shaft extending axially with a front end designed to carry the impeller of the pump and rotating around an axis of rotation;
at least one electromagnetic friction clutch arranged between a movement take-up element for taking up a rotational movement from the combustion engine and the driven shaft;
an electric drive comprising a stator and a rotor for driving the driven shaft independently of the movement take-up element;
a fixed support body extending axially between a front part which carries the front end of the shaft and a rear end which rotationally supports the movement take-up element;
wherein the support body is made of two parts and comprises a first front body part which is proximal to said front end of the shaft and is designed to be fastened to a fixed base, and a bell member fastened to the first body part along a front end of the bell member extending radially away from the axis of rotation of the shaft and comprising an axial extension which supports the movement take-up element adjacent to the electromagnetic clutch via a bearing arranged in between,
wherein said bell member further comprises a front axial and radially outer section extending axially fully between the front end of the bell member and a radial section of the bell member, the radial section extending from the front axial and radially outer section towards the axis of rotation of the shaft, and said axial extension extending from the radial section and is axially distal from the impeller, and
wherein the stator of the electric drive is arranged inside the bell member and integral with the front axial and radially outer section of the bell member such that the front axial and radially outer section extends an entire axial length of the stator.
2 . The operating assembly according to claim 1 , wherein a first bearing is arranged between the shaft and the first front body part of the support body and a second bearing is arranged between the bell member and the shaft.
3 . The operating assembly according to claim 1 , wherein the electromagnetic clutch comprises:
a fixed electromagnet rigidly joined with the bell member;
a rotor which receives the rotational movement transmitted by the movement take-up element;
an armature arranged facing the electromagnet, with a front surface of the rotor arranged between the electromagnet and the armature.
4 . The operating assembly according to claim 3 , wherein the rotor of the electromagnetic clutch is supported by the said axial extension of the bell member via said bearing arranged in between.
5 . The operating assembly according to claim 1 , wherein said movement take-up element is a pulley formed on a radially outer section of a rotor opposite to a radially inner section supported on the bearing supported by the support body.
6 . The operating assembly according to claim 1 , wherein an armature of the electromagnetic clutch has, mounted thereon, an elastic lamina fastened to a flange in turn integrally joined with a rear end of the shaft opposite to the front end supporting the impeller, so that the armature is rotationally integral with the flange and the driven shaft, but is able to perform movements in the axial direction with respect to the driven shaft towards/from a rotor of the electromagnetic clutch.
7 . The operating assembly according to claim 3 , wherein, when the electromagnet is de-energized, the armature is recalled by an elastic lamina axially away from the electromagnet, disengaging the rotor from the armature so that the flange and the driven shaft remain idle, and, when the electromagnet is energized, an induced magnetic field overcomes the elastic resistance of the lamina, axially recalls the armature with the consequent engagement thereof with the rotor and rotational driving of the shaft of the impeller with the movement obtained from the movement take-up element.
8 . The operating assembly according to claim 3 , wherein the rotor is concentrically arranged so as to contain the electromagnet inside it.
9 . A recirculating pump, comprising an operating assembly according to claim 1 and the impeller mounted on the front end of the driven shaft.
10 . The operating assembly according to claim 1 , wherein the shaft is rotationally supported by the first front body part with an arrangement of a first double bearing in between.
11 . The operating assembly according to claim 1 , wherein the shaft is rotationally supported by the bell member with an arrangement of a second double bearing in between.