Electric fluid pump with heating element

Abstract

The present invention relates to an electric fluid pump (100a, 100b, 100c) comprising a housing (111), an electric motor (10), a pump unit (50) and a control unit (30). The housing (111) is provided with at least one suction port (70) and at least one pressure port (90). The electric motor (10) has a stator (12) and a rotor (14) rotatable about an axis of rotation (X). The pump unit (50) in driving connection with the rotor (14) has a suction inlet (72) in fluid connection with the suction port (70) and a pressure outlet (92) in fluid connection with the pressure port (90). The control unit (30) is used to drive the electric motor (10). The electric fluid pump (100a, 100b, 100c) further comprises a heating element (20, 21), at least a portion of the heating element (20, 21) being arranged in the suction port (70) and electrically connected to the control unit (30). Figure for abstract: Figure 1

Description

Title of the invention: Electric fluid pump with a heating element

[0001] The present invention relates to an electric fluid pump, in particular an electric fluid pump provided with a heating element more particularly suitable for automotive applications.

[0002] In general, the automobile drive train is equipped with various components that require lubrication. These components are normally lubricated using a lubricating fluid. The lubricating fluid is circulated within the drive train using a fluid pump.

[0003] Generally, in a colder environment, the temperature of the lubricating fluid decreases. This leads to an increase in the viscosity of the lubricating fluid in the vehicle drive train, which deteriorates the fluidity of the fluid. This results in solidification of the fluid causing the impeller of the fluid pump to be retarded. This makes it difficult to operate the fluid pump driven by an electric motor. Normally, the efficiency of the fluid pump driven by an electric motor in the automobile is not considered in relation to the temperature of the fluid that must be circulated inside the drive train.

[0004] It is therefore necessary to solve the technical problem associated with the assembly explained above.

[0005] Accordingly, it is an object of the present arrangement to provide an assembly which overcomes the aforementioned and other disadvantages of known arrangements and to provide an electric fluid pump having improved efficiency in maintaining oil temperature.

[0006] The present arrangement relates to an electric fluid pump comprising a housing having at least one suction port and at least one pressure port, an electric motor having a stator and a rotor rotatable about an axis of rotation, a pump unit which is in driving connection with the rotor and having a suction inlet in fluid connection with the suction port and a pressure outlet in fluid connection with the pressure port, a control unit for driving the electric motor, the electric fluid pump comprising a heating element. According to the invention, at least a part of the heating element is arranged in the suction port and is electrically connected to the control unit. Therefore, because the heating element is arranged in the suction port, the viscosity of the fluid can be reduced before entering the suction inlet.As a result, the efficiency of the engine-driven fluid pump . Electric fluid pump operating in a colder environment can be improved. The fact that the heating element is connected to the pump's electronic components means that the electric fluid pump is much more compact and easier to integrate into the vehicle.

[0007] According to one aspect of the arrangement, the at least one suction orifice extends along an axis and the heating element is arranged substantially coaxially with this axis.

[0008] According to another aspect of the arrangement, the heating element is a resistive element.

[0009] According to another aspect of the arrangement, the heating element is a thermistor, including an element with a positive temperature coefficient.

[0010] According to another aspect of the arrangement, the heating element is a coating, an ink, a flexible film, a metal wire or a coil.

[0011] According to another aspect of the arrangement, the heating element is arranged over at least 20% of the length of the at least one suction port along the axis. Therefore, the contact area of ​​the heating element with the fluid can be improved.

[0012] According to another aspect of the arrangement, an electrical line extends through the electric fluid pump to electrically connect the control unit and the heating element.

[0013] According to another aspect of the arrangement, the pump unit is a gerotor, a gear, a vane or a centrifuge.

[0014] According to another aspect of the arrangement, the fluid is oil for lubricating a vehicle transmission system.

[0015] According to another aspect of the arrangement, the casing is thermally insulated. The oil should be kept warm inside the electric fluid pump. This means that when the outside temperature is for example -30 °C, the oil is heated at the inlet, flows into the internal volume of the pump and exits. During all this movement inside the pump, the casing should thermally insulate the oil in the electric fluid pump from the external temperature. Alternatively, an insulation layer can be added around the casing.

[0016] The present arrangement may be better understood with reference to the following description and drawings. The components in the figures are not necessarily to scale, the emphasis being rather on illustrating the principles of the arrangement. In addition, in the figures, like reference numerals designate corresponding parts. In the drawings:

[0017] [Fig.l] illustrates a cross-section of an electric fluid pump having a heating element, configured according to the present invention;

[0018] [Fig.2] illustrates a sectional view of a second embodiment of an electric fluid pump with a heating element, configured according to the present invention;

[0019] [Fig.3] illustrates a sectional view of a third embodiment of an electric fluid pump with a heating element, configured according to the present invention.

[0020] In the following description, reference is made to the accompanying drawings, which are part thereof, and in which there are illustrated in an illustrative manner specific embodiments in which the invention may be applied. These embodiments are described in sufficient detail to enable a person skilled in the art to practice the invention, and it will be understood that the embodiments may be combined or other embodiments may be used and that structural and logical modifications may be made without departing from the scope of the present invention. The following detailed description should therefore not be construed as limiting and the scope of the present invention is defined by the appended claims and their equivalents.

[0021] The present description refers to [Fig.l], [Fig.2] and [Fig.3] described in common for reasons of brevity.

[0022] The electric fluid pump 100a, 100b, 100c with a heating element 20, configured according to the present invention, comprises a housing 111 on which an electric motor 10, a pump unit 50 and a control unit 30 are mounted. The electric fluid pump circulates a fluid in an automobile transmission.

[0023] In a non-limiting example, the housing is formed as a dedicated housing 111 formed as a single piece. In another example not shown, the housing 111 may be formed as a separate housing for the electric motor 10, the pump unit 50, and the control unit 30.

[0024] The housing 111, which is primarily an injection-molded component, consists of substantially three parts, namely, from left to right, the control unit part 113, the electric motor part 101, the pump unit part 115.

[0025] The housing 111 extends substantially transversely to an axis of rotation X, forms an outer cover on a first side 11 to form a first partition wall 13 receiving the control unit 30 between the first side 11 and the first partition wall 13 forms the control unit part 113. The housing 111 extends substantially transversely to an axis of rotation X, forms an outer cover on a second side 17 configured with at least one suction port 70 and at least one pressure port 90. The housing 111 extends substantially transversely to an axis of rotation X to form a second partition wall 15 receiving the pump unit 50 between the second side 17 and the second partition wall forms the pump unit part 115. The electric motor 10 is arranged between the pump unit 50 and the control unit 30 delimited by the first partition wall 13 and the second partition wall 15.

[0026] The electric motor 10 is implemented in the form of an internal rotor motor and comprises a stator 12 and a rotor 14. The rotor 14 is received inside the stator 12 leaving an annular space facilitating the rotation of the rotor 13 about the axis of rotation X. The rotor 14 is mounted on a rotor shaft 16. The pump unit 50 comprises an impeller 52. The pump unit 50 is in driving connection with the rotor 14. The driving connection implies that the rotor 14 of the electric motor 10 and the impeller 52 of the pump unit 50 are coaxially aligned and that the impeller 52 is assembled on the rotor shaft 16 of the electric motor 10. The electric motor 10 drives the impeller 52 of the pump unit 50.

[0027] The pump unit 50 further comprises a suction inlet 72 and a pressure outlet 92. The suction inlet 72 is fluidly connected to the suction port 70 and the pressure outlet 92 is fluidly connected to the pressure port 90. Rotation of the impeller 52 of the pump unit 50 creates a vacuum near the suction inlet 72 which draws fluid past the suction port 70. The introduced fluid is pressurized near the pressure outlet 92 in the pump unit 50 and pumped through the pressure port 90 out thereof.

[0028] The control unit 30 serves to drive the electric motor 10 and to give instructions to the heating element 20. An electrical line 25 is equipped to communicate the instruction from the control unit 30 to the heating element 20, 21. The electrical line 25 is integrated in the housing 111, preferably in the peripheral walls. The control unit 30 has an electrical connection (not shown) provided to control and distribute the required electrical power to the electric motor 10 and the heating element 20, 21. At least a part of the heating element 20, 21 is arranged in the suction port 70 and is electrically connected to the control unit 30.

[0029] Preferably, the suction orifice 70 extends along an axis XI and the heating element 20 is arranged substantially coaxially with this axis XL. The axis XI is parallel to the axis X. In a non-limiting manner, the heating element 20, 21 is arranged over at least 20% of the length of the at least one suction orifice 70 along the axis XL.

[0030] The suction port 70 which extends axially from the housing 111 is arranged relative to the axis XI and is placed radially outwardly at a distance from the rotation axis X on the second side 17 of the housing. The heating element 20, 21 is arranged on the inner wall of the suction port 70. The control unit 30 instructs an operating time for the heating element 20, 21. Thus, the heating element 20, 21 can be heated well before the rotation of the electric fluid pump 100a, 100b, 100c which then heats the fluid to lower the viscosity of the fluid.

[0031] A temperature sensor (not shown) is in contact with the fluid for example at the suction port 70, and senses the fluid temperature. Based on feedback from the temperature sensor, the control unit 30 energizes the heating element 20, 21, thereby heating the fluid adjacent thereto. As a result, the fluid temperature increases in the suction port 70 and in the suction inlet 72 adjacent to the impeller 52.

[0032] Generally, the control unit 30 is configured to energize the heating element 20, 21 before the vehicle engine starts.

[0033] The control unit 30 may be configured to energize the heating element 20, 21 based on input from a cabin heating system of the vehicle. The cabin of the vehicle is heated prior to vehicle start by the cabin heating system based on user preferences. From this input, the control unit 30 is informed that the temperature of the environment is low and begins energizing the heating element 20, 21 to increase the temperature of the fluid.

[0034] The control unit 30 may also be configured to energize the heating element 20, 21 based on input from the driver opening the vehicle.

[0035] In one embodiment, the heating element 20, 21 is a resistive element. In another embodiment, the heating element 20, 21 is a thermistor, preferably a positive temperature coefficient element made of solid-state ceramic chips that acts as an overheating protection means.

[0036] In one example, the positive temperature coefficient element has a first side and a second side. The first side is arranged complementary to the interior side of the suction port 70 and the second side is submerged by / in contact with the fluid for heating the fluid.

[0037] In a first embodiment shown in [Fig. 1], the heating element 20 is for example a coating or an ink. The periphery / inner wall of the suction orifice 70 is suitably adapted to have the printing of the ink or the coating of the heating element 20.

[0038] As a variation of this first embodiment, the heating element 20 is a flexible film. The flexible film may be a strip-type heating element having a heating side and a securing side. The securing side is secured to the inner periphery of the suction port 70 and the heating side is in contact with the fluid.

[0039] In other embodiments shown in [Fig. 2] and [Fig. 3], the heating element 21 is a metal wire. In a non-limiting manner, the metal wire is arranged in the form of a spiral or a coil having at least one turn. An axis of the coil is arranged substantially coaxially with the axis XI of the orifice suction 70.

[0040] In the embodiment shown in [Fig. 3], the heating element 21 is partially extended within the suction inlet 72 adjacent the impeller. The suction inlet 72 is adapted to receive the heating element 21 extended adjacent the impeller 52. The heating element 21 is arranged in the suction port 70 and the suction inlet 72 such that the heating element 21 is completely surrounded by the fluid. The fluid is heated by the heating element 21 and is thus brought to a desired temperature. This can be done uniformly and with relatively little energy input in a short period of time due to the arrangement of the heating element 21 within the length of the suction port 70.

[0041] As illustrated in [Fig.l], [Fig.2] and [Fig.3], an electrical line 25 extends through the electric fluid pump 100a, 100b, 100c to electrically connect the control unit 30 and the heating element 20, 21.

[0042] In one example, the impeller 52 of the pump unit 50 is, for example, a gerotor. In another example, the impeller 52 of the pump unit 50 may be a gear pump or a vane pump or a centrifugal pump.

[0043] Throughout the embodiment, the fluid is a lubricating oil. The electric fluid pump 100a, 100b, 100c circulates the lubricating oil for lubrication of a vehicle transmission system.

Claims

Claims

1. An electric fluid pump (100a, 100b, 100c) comprising a housing (111) having at least one suction port (70) and at least one pressure port (90), an electric motor (10) having a stator (12) and a rotor (14) rotatable about an axis of rotation (X), a pump unit (50) which is in driving connection with the rotor (14) and having a suction inlet (72) in fluid connection with the suction port (70) and a pressure outlet (92) in fluid connection with the pressure port (90), a control unit (30) for driving the electric motor (10), the electric fluid pump (100a, 100b, 100c) comprising a heating element (20, 21), characterized in that at least a part of the heating element (20) is arranged in the suction port (70) and is electrically connected to the control unit (30).

2. Electric fluid pump according to claim 1, characterized in that the at least one suction port (70) extends along an axis (XI) and the heating element (20, 21) is arranged substantially coaxially with this axis (XI).

3. Electric fluid pump according to claim 1, characterized in that the heating element (20, 21) is a resistive element.

4. Electric fluid pump according to claim 3, characterized in that the heating element (20, 21) is a thermistor, in particular an element with a positive temperature coefficient.

5. An electric fluid pump according to claim 3 or 4, characterized in that the heating element (20, 21) is a coating, an ink, a flexible film, a metal wire or a coil.

6. Electric fluid pump according to one of the preceding claims, characterized in that the heating element (20, 21) is arranged over at least 20% of the length of the at least one suction port (70) along the axis (XI).

7. An electric fluid pump according to one of the preceding claims, characterized in that an electrical line (25) extends through the electric fluid pump (100a, 100b, 100c) in order to electrically connect the control unit (30) and the heating element (20, 21).

8. Electric fluid pump according to one of the preceding claims, characterized in that the pump unit (50) is a gerotor, a gear, a vane or a centrifuge.

9. An electric fluid pump according to one of the preceding claims, characterized in that the fluid is oil for lubricating a vehicle transmission system.

10. Electric fluid pump according to one of the preceding claims, characterized in that the casing (111) is thermally insulated.

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