MOTOR VEHICLE COOLING CIRCUIT

Abstract

A cooling circuit for a vehicle, in particular a motor vehicle, includes a pump having at least one rotor that is driven in rotation by a motor and configured to force the circulation of cooling liquid in the circuit. The at least one rotor includes at least one driving screw that is driven by the motor, and at least one driven screw that is driven by the at least one driving screw, the driving screw(s) and driven screw(s) being configured to force the circulation of cooling liquid in the circuit.

Claims

1. A cooling circuit for a vehicle, this circuit having a pump having at least one rotor that is driven in rotation by a motor and configured to force the circulation of cooling liquid in the circuit, characterized in that said at least one rotor comprises at least one driving screw that is driven by said motor, and at least one driven screw that is driven by said at least one driving screw, the driving screw and the driven screw being configured to force the circulation of cooling liquid in the circuit.

2. The circuit as claimed in claim 1, wherein the circuit comprises one driving screw that is aligned with a shaft of the motor, and one or more driven screw(s) that extend parallel to the driving screw and are meshed with this driving screw.

3. The circuit as claimed in claim 1, wherein the circuit comprises two driving screws that are parallel to a shaft of the motor and driven by the motor by a gear train, and driven screws that extend parallel to the driving screws and are meshed with the driving screws.

4. The circuit as claimed in claim 1, wherein a number of driving screw(s) and driven screw(s) of the pump is between 2 and 16.

5. The circuit as claimed in claim 1, wherein the driving screw and the driven screw are mounted and guided in rotation in cylindrical recesses of a single fixed body of the pump.

6. The circuit as claimed in claim 5, wherein the fixed body is mounted at one end of the motor.

7. The circuit as claimed in claim 1, wherein the driving screw and the driven screw are made of plastic or composite material.

8. The circuit as claimed in claim 1, wherein the pump is fastened to a reservoir of cooling liquid.

9. The circuit as claimed in claim 1, also having a heat exchanger, at least one element to be cooled and a temperature sensor, the circuit having no proportional valve and said pump being configured so as to be controlled by a control unit in accordance with signals emitted by said temperature sensor.

10. A vehicle, having at least one circuit as claimed in claim 1.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0020] Other features and advantages of the invention will become apparent while reading the following detailed description, for the understanding of which reference will be made to the appended drawings, in which:

[0021] FIG. 1 is a schematic view of a vehicle cooling circuit,

[0022] FIG. 2 is a schematic view of a vehicle cooling circuit, according to one embodiment of the invention,

[0023] FIG. 3 is a schematic perspective view of a reservoir of cooling liquid equipped with a screw pump,

[0024] FIG. 4 is an exploded schematic perspective view of a first embodiment of a screw pump,

[0025] FIG. 5 is an exploded schematic perspective view of a second embodiment of a screw pump,

[0026] FIG. 6 is an exploded schematic perspective view of a third embodiment of a screw pump.

DETAILED DESCRIPTION

[0027] FIG. 1 has been described above.

[0028] FIG. 2 illustrates a cooling circuit 24 within the meaning of the invention. This circuit 24 comprises at least one screw pump 26. The circuit 24 also comprises a reservoir 10 of cooling liquid.

[0029] The screw pump 26 and the reservoir 10 may be two separate elements connected by at least one pipe, or they may be mounted on one another as in the example in FIG. 3 in which the pump 26 is fastened directly to the reservoir 10.

[0030] It is understood that the pump 26 comprises an inlet 26a connected to the reservoir 10 or opening into this reservoir, and an outlet 26b.

[0031] The screw pump 26 is connected to a heat exchanger 14 and to an element 16 to be cooled. The outlet 26b of the pump 26 is connected to an inlet 14a of the exchanger 14 of which an outlet 14b is connected to an inlet 16a of the element 16. This element 16 comprises an outlet 16b connected to the inlet 26a of the pump 26 or to the reservoir 10.

[0032] The element 16 is equipped with a temperature sensor 20 of which the signals are transmitted to a control unit 18 for controlling the screw pump 26 in order to regulate the flow rate of cooling liquid leaving the pump 26 and supplying the heat exchanger 14.

[0033] A screw pump 26 comprises at least one driving screw that is driven by a motor, and at least one driven screw that is driven by the driving screw(s), the driving screw(s) and driven screw(s) being configured to force the circulation of cooling liquid in the circuit.

[0034] FIGS. 4 to 6 illustrate exemplary embodiments of a screw pump 26.

[0035] In the embodiment in FIG. 4, the pump 26 comprises one driving screw 28 and one driven screw 30. The driving screw 28 has an elongate shape and comprises an end connected to a drive shaft 32 of the motor 33, which is for example an electric motor.

[0036] The screw 28 comprises a helicoidal thread that extends substantially over its entire length. The screw 28 is housed in a central first recess 34 of a cylindrical body 36 of the pump 26.

[0037] The driven screw 30 has an elongate shape and extends alongside the driving screw 28, parallel thereto. The screw 30 comprises a helicoidal thread that extends substantially over its entire length and is complementary to that of the screw 28, so that the screws are meshed and the screw 30 is driven in rotation by the screw 28, which is itself driven in rotation by the shaft 32.

[0038] The screw 30 is housed in a lateral second recess 38 of the body 36. The recesses 34, 38 communicate with one another, as illustrated in the drawing.

[0039] The body 36 is fastened to one end of the motor 33, and comprises for example at one axial end an annular fastening flange 36a.

[0040] In the embodiment in FIG. 5, the pump 26 comprises one driving screw 28 and three driven screws 30. The driving screw 28 has an elongate shape and comprises an end connected to the drive shaft 32 of the motor.

[0041] The screw 28 comprises a helicoidal thread that extends substantially over its entire length. The screw 28 is housed in a central first recess 34 of a cylindrical body 36 of the pump 26.

[0042] The driven screws 30 each have an elongate shape and extend alongside the driving screw 28, parallel thereto. They are regularly spaced apart from one another around the screw 28. Each screw 30 comprises a helicoidal thread that extends substantially over its entire length and is complementary to that of the screw 28, so that the screws are meshed and so that each screw 30 is driven in rotation by the screw 28, which is itself driven in rotation by the shaft 32.

[0043] The screws 30 are housed in lateral recesses 38 of the body 36. The recesses 34, 38 communicate with one another, as illustrated in the drawing.

[0044] The body 36 is fastened in a cowling 40 that is fastened to one end of the motor. This cowling 40 defines the inlet 26a and the outlet 26b of the pump 26.

[0045] In the embodiment in FIG. 6, the pump 26 comprises two driving screws 28 and two driven screws 30. Each driving screw 28 has an elongate shape and comprises a helicoidal thread that extends substantially over its entire length. The driving screws 28 are disposed in parallel and side by side, and are housed in first recesses 34 of the body 36.

[0046] Each screw 28 bears a pinion 42 at one axial end. A toothed wheel 44 is disposed between the pinions 42 that are secured to the screws 28, and is meshed with these pinions so as to form a gear train. The toothed wheel 44 is mounted on the drive shaft of the motor (not visible) and drives the screws 28 by means of the pinions 42.

[0047] The driven screws 30 each have an elongate shape and extend alongside the driving screws 28, parallel thereto. The axes of rotation of the screws 28, 30 are parallel and are situated for example at four corners of a parallelepiped.

[0048] Each screw 30 comprises a helicoidal thread that extends substantially over its entire length and is complementary to that of the screw 28, so that the screws are meshed and so that each screw 30 is driven in rotation by one of the screws 28.

[0049] The screws 30 are housed in lateral recesses 38 of the body 36. The recesses 34, 38 communicate with one another, as illustrated in the drawing.

[0050] As in the preceding embodiment, the body 36 is mounted in a cowling 40 that is fastened to one end of the motor. This cowling 40 defines the inlet and the outlet 26b of the pump 26.

[0051] In the various embodiments described above, the screws 28, 30 are advantageously made from plastic or composite material. They are for example produced by injection molding, which makes it possible to have screws with complex shapes at a relatively limited cost.

[0052] The invention affords a number of advantages, such as one or more of the following: [0053] the reduced cost of a screw pump, in particular by using injected-plastic screws; [0054] a current consumption of the motor 33 that is proportional to the flow rate of the pump 26; this allows energy to be saved relative to a centrifugal pump when a low flow rate of liquid is necessary; [0055] the screw pump 26 allows the circulation of liquid in the circuit to be stopped when the motor 33 is not in operation; this may for example allow a valve for closing the circuit of the prior art to be omitted; [0056] the flow rate of the pump is directly proportional to the speed of rotation of the motor; the pump can be directly controlled in accordance with the temperature of the element to be cooled 16; [0057] the transfer of liquid can take place in both directions and depends on the direction of rotation of the motor; whereas in a centrifugal pump the liquid can only travel in one direction; [0058] the screw pump has a better hydraulic efficiency; this means that the current consumption is lower for the same volume of liquid transferred; [0059] the screw pump allows a higher pressure to be obtained relative to a centrifugal pump, regardless of the speed of its rotor; [0060] the screw pump provides a flow rate of liquid at the outlet that is proportional to the speed of rotation of the motor; [0061] there is no cavitation phenomenon in a screw pump; and [0062] the screw pump is relatively compact and is easy to incorporate into a reservoir of cooling liquid.