Control device for a recirculation pump having a multistage bearing fixed on a pump body

Abstract

The present application relates to an operating device for operating an impeller (1) of a pump (10) for recirculating a coolant fluid of a vehicle, comprising: a driven shaft (2) arranged to support and rotate the impeller (1) of the pump (10); a fixed pump body (11); a motion receiving element (31a) for receiving a rotational motion; an electromagnetic clutch comprising an electromagnet (22) and an armature (40) rotating integrally with the driven shaft (2) and axially movable with respect to said shaft, these devices cooperating to drive the driven shaft at a first rotational speed, so as to transmit the rotational motion taken from the motion receiving element (31a); an eddy current or Foucault coupling arranged to transmit to the shaft (2) a rotational motion proportional and reduced with respect to the rotational motion of the motion receiving element (31a). The motion receiving element is formed on a coaxial rotor (30) having a front friction surface (32a) arranged between the electromagnet (22) and the armature (40); the pump body (11) is rigidly connected to an intermediate bearing (20b) of a multi-stage bearing unit (20) which further comprises: an inner race (20a) to which the driven shaft is keyed; and an outer race (20c) on which the coaxial rotor is supported. The driving portion of the Foucault coupling rotates integrally with the rotor, the driven portion (61) rotating integrally with the shaft (2).

Description

Technical Field

[0001] The present invention relates to an operating device for operating the impeller of a pump used to recirculate coolant fluid in vehicles, etc. Background Technology

[0002] In the field of engine manufacturing, it is known that engines need to be cooled by recirculating coolant fluid, which is moved by a corresponding recirculation pump whose impeller is driven by a belt connected to a drive shaft.

[0003] It is also known that the recirculation of coolant fluid must be carried out at a flow rate corresponding to the actual cooling requirements, which are determined by the actual operating conditions and external temperature. Summary of the Invention

[0004] Therefore, the technical problem proposed is to provide an operating device for operating the impeller of a pump used to recirculate coolant fluid in vehicles, etc., and the operating device is capable of generating a change in the impeller rotation speed.

[0005] Regarding this issue, it is also required that the device be easy to manufacture and assemble, and have a compact size, especially the axial size, but the radial size should also be compact.

[0006] According to the present invention, these technical problems are solved by an operating device for operating the impeller of a pump according to claim 1, the pump being used to recirculate coolant fluid in vehicles, etc. Attached Figure Description

[0007] Other features will become clear from the following description of a non-limiting example of an embodiment of a device according to the invention, with reference to the accompanying drawings, in which:

[0008] Figure 1 A schematic cross-sectional view along the axial plane of the pump, which is equipped with an example embodiment of the device according to the invention. Detailed Implementation

[0009] like Figure 1 As shown, as conventionally defined, the pump 10, having an axial direction XX parallel to the axis of rotation of shaft 2; a radial direction perpendicular to the axis; a front portion and a rear portion opposite the front portion in the axial direction, is used to recirculate coolant fluid from vehicles, etc. The impeller 1 is mounted on the front end 2a of the driven shaft 2. The pump body 11 is fixed to the base 11a of the vehicle engine or to a support designed to house the volute of the pump. Shaft 2 is coaxially inserted into the pump body 11, wherein the front end 2a is arranged inside the pump body 11, in front of the sealing member 2b arranged between shaft 2 and the pump body itself.

[0010] Driven shaft 2 is rotatably supported by a multi-stage bearing unit 20, which includes: an inner race 20a to which impeller shaft 2 is keyed; an intermediate race 20b rigidly connected to pump body 11; and an outer race 20c supporting a coaxial rotor 30, the coaxial rotor 30 having a pulley 31 on its outer peripheral surface for receiving rotational motion, the pulley 31 constituting a preferred example of an element designed to receive rotational motion, for example by driving belt 3.

[0011] More specifically, the intermediate seat ring 20b is rigidly connected to the pump body 11 by an axial fixing member 21 of the screw type or the like, which engages in the pump body 11 once inserted through the intermediate seat ring 20b in the front-rear direction.

[0012] The coaxial rotor 30, receiving the rotational motion transmitted by the motion receiving element, has a cross-sectional shape with a radially outer axial branch 31 on which a pulley 31a is formed. This radially outer axial branch 31 is opposite to a radially inner axial branch 33 supported on the outer race 20c of the multi-stage bearing 20. A radial arm 32 connects the two axial branches 31 and 33 and has a front friction surface 32a facing the rear portion. The outer axial branch 31 of the rotor 30 extends axially rearward beyond the front surface 32a and is rigidly fastened to the rear disk 34, thereby defining an internal housing volume extending axially between the front surface and the rear disk. More specifically, the outer axial branch 31 extends axially beyond the rear end of the shaft 2, wherein the rear disk 34 is arranged to enclose the housing volume.

[0013] The electromagnetic clutch is arranged to transmit rotational motion from the rotor 30 to the driven shaft 2 at a first rotational speed, and includes an electromagnet 22 fixed on the pump body 11 and an armature 40 arranged to face forward toward the electromagnet 22, wherein the front surface 32a of the rotor 30 is arranged between the electromagnet 22 and the armature 40.

[0014] The excitation of the electromagnet can be remotely controlled, for example, via a connector 22a connected to a control unit. Preferably, the stationary electromagnet 22 comprises a solenoid arranged within a support, which is preferably in the form of a "C" or an "inverted C," and is then fixed to the pump body 11. Advantageously, to reduce the axial dimension, the electromagnet 22 is coaxially housed within the rotor 30, between the outer axial branch 21 and the inner axial branch 33, in front of the radial arm 32.

[0015] Preferably, the arrangement of the electromagnet, rotor 30, and multi-stage bearing unit 20 is substantially concentric. “Substantially concentric” should be understood as meaning that the same radial axis passes through the bearing unit 20, the electromagnet 22, and the rotor 30, accommodating the front portion of the electromagnet (at a substantially midpoint along their axial extension).

[0016] The armature 40 is rotatably constrained on the driven shaft 2, but can move axially relative to the driven shaft 2, particularly by means of the elastic sheet 41.

[0017] The thin sheet 41 is fastened to the hub 42 mounted on the rear end of the driven shaft 2. Therefore, by energizing the electromagnet 22, the armature can be brought against the front surface 32a of the rotor 30, thereby rotatably connecting the armature 40 and the rotor 30 so as to transmit the rotational motion of the rotor 30 to the driven shaft 2.

[0018] Hub 42 also supports the driven portion 61 of induction, eddy current or Foucault coupling 60, which is designed to transmit rotational motion to shaft 2 in proportion to the rotational motion of rotor 30 (at a slower second speed).

[0019] More specifically, in the preferred example shown, the driven portion of the Foucault connector includes a permanent magnet 61 mounted on an annular flange 61a fixed to the hub 42, in a position located behind the armature. Thus, the permanent magnet 61 can rotate with the shaft but is fixed in the axial direction.

[0020] The drive portion of the Foucault connector 60 includes a magnetic ring 62, which is radially engaged in the rear disk 34 so as to be arranged axially opposite to the permanent magnet 61, thereby closing the magnetic circuit and causing rotation to drive the driven portions 61, 61a.

[0021] The disk 34 is made of a non-magnetic material, such as aluminum or copper. In particular, the disk 34 can be a die-cast aluminum component, with the annular element 62 cast inside the disk 34. The disk 34 can also be used as a heat sink.

[0022] As shown in the figure, the armature 40 and the driven portion 61 are housed within the internal housing volume and between the rotor 30 and the rear disc 34.

[0023] Therefore, the arrangement of the device, extending axially, sequentially includes the pump body 11, the electromagnet 22, the front surface 33 of the rotor, the armature 40, the driven portion 61 of the connector 60, and the drive portion 62 of the Foucault connector. This arrangement is very compact in the axial direction, but also in the radial direction, especially when the electromagnet 22 is arranged coaxially (preferably concentrically) within the rotor 30, as shown in the example.

[0024] The multi-stage bearing unit 20 allows for a reduction in radial dimensions and effectively secures the rotor 30 and shaft 2 to the pump body, providing relative rotational freedom, even in cases of limited axial space. This avoids the use of systems such as riveting and / or adhesives, which are unreliable when considering the materials of the pump supports, the cleanliness of their surfaces and bearing surfaces, and thermal expansion. This is particularly disadvantageous in the case of materials with different coefficients of thermal expansion (e.g., in the case of an aluminum pump body). Furthermore, the bearing unit 20 allows for the effective release of belt tension from the motion receiving belt 31a.

[0025] The operating principle of this device is as follows:

[0026] When cooling requirements are limited:

[0027] - Electromagnet 22 is deactivated, so no attractive magnetic field is formed between rotor 30 and armature 40, which remains separated from the front friction surface;

[0028] - The rotation of the disc 34, which is integral with the rotor, causes the formation of a magnetic field and eddy currents (Foucault effect) between the permanent magnet 61 and the drive section 62, which includes a ring 62 that rotates integrally with the rear disc 34, thereby rotating the drive hub and (therefore) the shaft 2 at a slower speed than the speed of the motion receiving pulley 31, without contacting the disc 34.

[0029] When overheating occurs and it is necessary to increase the recirculation of coolant fluid:

[0030] - Excite the electromagnet 22 to generate an electromagnetic flux that attracts the armature 40 against the front surface of the rotor 30 in the axial direction.

[0031] - Due to the elastic ring 43, the armature moves axially toward the rotor and attaches itself to the rotor, thus firmly rotating and attaching to the rotor 30, and driving the shaft 2 at the same speed as the impeller 1, which is substantially the same as the rotor 30.

[0032] Therefore, it is evident how the device according to the invention can be used to obtain two different rotational speeds of the impeller of the recirculation pump, wherein one rotational speed is greater than the other, or equal to or less than the rotational speed of the pulley that generates the motion.

[0033] It is also clear how the operating device according to the invention is particularly suitable for operating the engine coolant recirculation pump or the oil pump for recirculating lubricant under conditions of high ambient temperature and limited axial and radial space in the engine compartment. This also results in low consumption levels because the action of the electromagnet can be limited to overheating conditions, and the fluid recirculation, which can be determined solely by the speed obtained from the Foucault connector, is usually sufficient.

[0034] Although the description is based on applications related to water pumps used for recirculating coolant fluid, it should be understood that the coolant fluid can also be a lubricant, such as oil, and therefore the operating components according to the invention can be used in oil pumps.

Claims

1. An operating device for operating an impeller (1) of a pump (10) for recirculating coolant fluid in a vehicle, the operating device comprising: Driven shaft (2), which is arranged to support and rotatably drive the impeller (1) of pump (10); Fixed pump body (11); A motion receiving element (31a) is used to receive rotational motion; An electromagnetic clutch comprising an electromagnetic component (22) and an armature (40) that rotates integrally with the driven shaft (2) and is axially movable relative to the driven shaft, the components being configured to drive the driven shaft at a first rotational speed to transmit rotational motion obtained from the motion receiving element (31a); An inductive or eddy current or Foucault connector is arranged to transmit rotational motion toward the shaft (2), the rotational motion being proportional to and reduced relative to the rotational motion of the motion receiving element (31a); The motion receiving element is formed on a coaxial rotor (30), which has a front friction surface (32a) arranged between an electromagnetic component (22) and an armature (40). The pump body (11) has: an intermediate bearing ring (20b) of a multi-stage bearing unit (20) rigidly connected thereto, the multi-stage bearing unit further including: an inner bearing ring (20a) on which the driven shaft (2) is keyed; and an outer bearing ring (20c) on which the coaxial rotor (30) is supported. The drive portion of the Foucault connector rotates integrally with the coaxial rotor, and the driven portion (61) of the connector rotates integrally with the driven shaft (2).

2. The operating device according to claim 1, wherein: The intermediate seat ring (20b) is rigidly connected to the pump body (11) by an axial fixing member (21), which is inserted through the intermediate seat ring (20a) in the front-back direction and engaged in the pump body (11).

3. The operating device according to any one of the preceding claims, wherein: The coaxial rotor (30) has a cross-sectional form having: a radially outer axial branch (31) on which a motion receiving element is formed, the radially outer axial branch being opposite to a radially inner axial branch (33) supported on the outer race (20c) of the multi-stage bearing unit (20); and a radial arm (32) connecting the two axial branches (31, 33) together and having the front surface (32a) facing the armature (40).

4. The operating device according to any one of the preceding claims, wherein: The outer axial branch of the rotor extends axially rearward beyond the front surface and is rigidly fastened to the rear disk (34), thereby defining the internal housing volume that extends axially between the front surface (32a) and the rear disk (34).

5. The operating device according to any one of the preceding claims, wherein: The armature (40) and the driven portion (61) are housed in an internal housing volume defined between the rotor (30) and the rear disc (34).

6. The operating device according to any one of the preceding claims, wherein: The electromagnetic component includes an electromagnet (22) fixed on the pump body (11), preferably including a solenoid arranged in a support member in the form of a "C" or "inverted C" and fixed in the pump body (11).

7. The operating device according to any one of the preceding claims, wherein: The armature (40) is rotatably constrained on the driven shaft (2), but is axially movable relative to the driven shaft by means of an elastic sheet (41).

8. The operating device according to any one of the preceding claims, wherein: The elastic sheet (41) is fastened to the hub (42) mounted on the rear end of the driven shaft (2), which is opposite to the front end (2a) for supporting the impeller.

9. The operating device according to any one of the preceding claims, wherein: The hub (42) also supports the driven portion (61) of the Foucault connector.

10. The operating device according to any one of the preceding claims, wherein: The driven portion of the connector includes a permanent magnet (61) mounted on an annular flange (61a), which is fastened to the shaft in a position behind the armature.

11. The operating device according to any one of the preceding claims, wherein: The drive portion of the connector (60) is formed by a conductive ring (62) which is radially engaged in the rear disc (34) so ​​as to be axially arranged opposite the driven portion (61).

12. The operating device according to any one of the preceding claims, characterized in that: An arrangement extending axially sequentially includes: a pump body (11), an electromagnet (22), a front surface (33) of a rotor, an armature (40), a driven portion (61) of a connector (60), and a driving portion (63) of the connector.

13. The operating device according to any one of the preceding claims, wherein: The electromagnet (22) is arranged coaxially within the rotor, particularly between the outer and inner axial branches of the rotor (30).

14. The operating device according to any one of the preceding claims, wherein: The motion receiving element (31a) is a pulley formed on the outer peripheral surface of the rotor, particularly on the outer peripheral surface of the radially outer axial branch (31).

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