An electric fluid pump with a heating element

Abstract

The present subject matter relates to an electric fluid pump (100a, 100b, 100c, 100d) includes a housing (111), an electric motor (10), a pump unit (50) and a control unit (30) The housing (111) with at least one suction port (70) and at least one pressure port (90).The electric motor (10) having a stator (12) and a rotor (14) rotatable about an axis of rotation X. The pump unit (50) in drive connection with the rotor (14) 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). The control unit (30) for driving the electric motor (10). The electric fluid pump (100a, 100b, 100c, 100d) further includes a heating element (20, 21, 22), with at least part of the heating element (20, 21) arranged on the housing (111) around the pump unit (50) and / or in the suction port (70) and electrically connected to the control unit (30).

Description

DescriptionTitle of the invention: An electric fluid pump with a heating element[1] The present subject matter relates to an electric fluid pump particularly to an electric fluid pump with a heating element more particularly suitable for automobile applications.[2] In general, drivetrain of the automobile is provided with various components that requires lubrication. These components are normally lubricated with the help of a lubricating fluid. The lubricating fluid is circulated within the drivetrain with the help of a fluid pump.[3] Usually in colder environment the temperature of the lubricating fluid reduces. That leads to an increase of the viscosity of the lubricating fluid in the drivetrain of the vehicle which deteriorates the fluidity of the fluid. This results in solidification of the fluid causing the rotating element of the fluid pump to retard which makes it difficult for the electric motor driven fluid pump to work. Normally, the efficiency of the electric motor driven fluid pump in the automobile is not considered with respect to the fluid temperature that is need to be circulated within the drivetrain.[4] There is therefore a need to solve the technical problem associated with the assembly explained above.[5] It is accordingly an object of the present arrangement to provide an assembly, which overcomes the above mentioned and other disadvantages of the known arrangements and provide an electric fluid pump with improved efficiency for maintaining the oil temperature.[6] 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 able to rotate about an axis of rotation X, a pump unit which is in drive 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 , wherein the electric fluid pump comprises a heating element. According to the invention, at least part ofthe heating element is arranged on the housing around the pump unit and / or in the suction port and is electrically connected to the control unit.[7] Therefore, by virtue of the heating element arranged around the pump unit on the housing and / or in the suction port, the viscosity of the fluid may be reduced. Accordingly, the efficiency of the electric motor driven fluid pump working in colder environment can be improved.[8] Moreover, the fact that the heating element is connected to the control unit means that the electric fluid pump is much more compact and easier to integrate into the vehicle. This also simplifies and improves heating control by synchronizing the electric motor control with the heating. Of course, electric motor and heating element can be controlled independently. For example, the heating element can be triggered before the electric motor starts rotating.[9] According to an aspect of the arrangement, the at least one suction port extends along an axis X1 and the heating element is arranged substantially coaxially with this axis X1 .

[0010] According to another aspect of the arrangement, the heating element is arranged on the inner or outer surface of the housing around the pump unit substantially coaxially with the axis X. Accordingly, the contact area of the heating element with the fluid can be improved in the region of the pump unit.

[0011] According to another aspect of the arrangement, the heating element is a resistive element.

[0012] According to another aspect of the arrangement, the heating element is a thermistor, notably a positive temperature coefficient element. This has the advantage to provide a self-regulating heating element as its electrical resistance increases as the temperature rises.

[0013] According to another aspect of the arrangement, the heating element is a coating, an ink, a flexible film, a wire or a coil.

[0014] According to another aspect of the arrangement, the heating element is arranged on at least 20% of the length of the at least one suction port along the axis X1 . Accordingly, the contact area of the heating element with the fluid can be improved.

[0015] According to another aspect of the arrangement, an electric line extend through the electric fluid pump in order to electrically connect the control unit and the heating element.

[0016] According to another aspect of the arrangement, the pump unit is a gerotor, a gear, a vane or a centrifugal.

[0017] According to another aspect of the arrangement, the fluid is oil for lubrication, cooling or actuation purpose of a vehicle transmission system.

[0018] According to another aspect of the arrangement, the housing is thermally insulated. The oil should be kept hot inside the electric fluid pump. This means that when the outside temperature is for example -30°C, the oil is heated up at the entrance, flow the internal volume of the pump unit and comes out. During all that travel inside the pump, the housing should thermally insulate the oil in the electric fluid pump from the external temperature. As an alternative, an insulation layer can be added around the housing.

[0019] The present arrangement can be better understood with reference to the following description and drawings. The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the arrangement. Moreover, in the figures, like reference numerals designate corresponding parts.

[0020] In the drawings:

[0021] [Figure 1] illustrates a cut-section of a first embodiment of an electric fluid pump with a heating element, configured in accordance with the present subject matter;

[0022] [Figure 2] illustrates a cut-section of a second embodiment of an electric fluid pump with a heating element, configured in accordance with the present subject matter;

[0023] [Figure 3] illustrates a cut-section of a third embodiment of an electric fluid pump with a heating element, configured in accordance with the present subject matter;

[0024] [Figure 4] illustrates a cut-section of a fourth embodiment of an electric fluid pump with a heating element, configured in accordance with the present subject matter.

[0025] In the description that follows, reference is made to accompanying drawings, which form part thereof, and in which is shown by way of illustration specific implementations in which the invention may be practiced. These implementations are described in sufficient detail to enable that skilling in the art to practice the invention, and it is to be understood that the implementations may be combined, or that other implementations may be utilized, and that structural and logical changes may be made without departing from the scope of the present invention. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is defined by the appended claims and their equivalents.

[0026] The description herein pertains to [Figure 1], [Figure 2], [Figure 3] and [Figure 4] described in a common manner for the sake of brevity.

[0027] The electric fluid pump 100a, 100b, 100c, 10Od with a heating element 20, 21 , 22 configured in accordance with the present subject matter includes 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.

[0028] In a non-limiting example the housing is formed as one integrally formed dedicated housing 111. In another example that is not shown but covered by the present invention, the housing 111 may be formed as a separate housings for the electric motor 10, the pump unit 50 and the control unit 30.

[0029] The housing 111 , is in plastic, for example an injection molded component. The housing 111 consists of three portions, namely from left to right starting from a control unit portion 113, an electric motor portion 101 , a pump unit portion 115.

[0030] The housing 111 comprises an outer cover on a first side 11 to form with a first partition wall 13 the control unit portion 113. The control unit 30 is received axially between the first side 11 and the partition wall 13. The partition wall 13 may be optional in the context of a control unit 30 in direct contact with the fluid.

[0031] The housing 111 comprises an outer cover on a second side 17 configured with at least one suction port 70 and at least one pressure port 90.

[0032] The housing 111 comprises a second partition wall 15 receiving the pump unit 50 in between the second side 17 and the second partition wall 15 forming the pump unit portion 115. The second partition wall 15 may comprise at least one opening to let the fluid circulate in contact with the electric motor 10.

[0033] The electric motor 10 is disposed axially in between the pump unit 50 and the control unit 30 delimited by the first partition wall 13 and the second partition wall 15.

[0034] The electric motor 10 is executed as an internal rotor motor and includes a stator 12 and a rotor 14. The rotor 14 is received within the stator 12 leaving an annular gap facilitating rotation of the rotor 13 about the axis of rotation X. The rotor 14 is mounted on a rotor shaft 16.

[0035] The pump unit 50 includes a rotating element 52 to pressurize and / or accelerate the fluid flow. The pump unit 50 is in drive connection with the rotor 14. The drive connection implies that the rotor 14 of the electric motor 10 and the rotating element 52 of the pump unit 50 are coaxially aligned and the rotating element 52 is assembled on the rotor shaft 16 of the electric motor 10. The electric motor 10 drives the rotating element 52 of the pump unit 50.

[0036] The pump unit 50 further includes a suction inlet 72 and a pressure outlet 92. The suction inlet 72 is in fluid connection with the suction port 70 and the pressure outlet 92 is in fluid connection with the pressure port 90. The rotation of the rotating element 52 of the pump unit 50 creates a vacuum near the suction inlet 72 that draws the fluid past the suction port 70. The fluid entered is pressurized near the pressure outlet 92 in the pump unit 50 and pumped out through the pressure port 90.

[0037] The control unit 30 is for driving the electric motor 10 and instructing the heating element 20, 21 , 22. An electric line 25 is equipped to communicate the instruction from the control unit 30 to the heating element 20, 21 , 22. The electric line 25 is integrated in the housing 111 , preferably in the peripheral walls. As an alternative, the electric line 25 can be arranged against the peripheral walls of the housing 111 , on the inner or outer side. The control unit 30 includes an electrical connection (not shown) provided to control and distribute the required power supply to the electric motor 10 and the heating element 20, 21 , 22.

[0038] In all embodiments at least part of the heating element 20, 21 is arranged in the suction port 70 and is electrically connected to the control unit 30.

[0039] In the fourth embodiment shown on [Figure 4], the heating element 22 is also arranged on the inner or outer surface of the housing 111 around the pump unit 50 substantially coaxially with the axis X in addition to the heating element 20, 21 arranged in the suction port 70. Within the scope of the invention, it is also possible to have the heating element 22 arranged on the inner or outer surface of the housing 111 around the pump unit 50 alone without heating element 20, 21 arranged in the suction port 70.

[0040] Preferably, the suction port 70 extends along an axis X1 and the heating element 20, 21 is arranged substantially coaxially with this axis X1 . Axis X1 is parallel to axis X. In a non-limiting manner the heating element 20, 21 is arranged on at least 20% of the length of the at least one suction port 70 along the axis X1 .

[0041] The suction port 70 that extends axially from the housing 111 is arranged with respect to the axis X1 and is placed radial outward at a distance from the axis of rotation X on the second side 17 of the housing. The heating element 20, 21 is disposed on the inner wall of the suction port 70.

[0042] The control unit 30 instructs an operation duration for the heating element 20, 21 , 22. Thus the heating element 20, 21 , 22 can be heated well before the rotation of the electric fluid pump 100a, 100b, 100c, 100d which subsequently heats the fluid to lower the viscosity of the fluid.

[0043] A temperature sensor (not shown) is in contact with the fluid for example at the suction port 70 or in the pump unit 50, and senses the fluid temperature. Based on the feedback from the temperature sensor, the control unit 30 energizes the heating element 20, 21 , 22 thereby heating the fluid adjacent to it. As a result the temperature of the fluid rises in the suction port 70 and in the pump unit 50.

[0044] Generally, the control unit 30 is configured in such a way to energize the heating element 20, 21 , 22 before the vehicle engine starts.

[0045] The control unit 30 can be configured in such a way to energize the heating element 20, 21 , 22 based on the input from a cabin heating system of the vehicle. The cabin of the vehicle gets heat up before the start of the vehicle by the cabin heating system based on the user preferences. From this input the control unit 30get to know that the temperature of the surrounding is low and starts to energize the heating element 20, 21 , 22 to increase the temperature of the fluid.

[0046] The control unit 30 can also be configured in such a way to energize the heating element 20, 21 , 22 based on the input from the opening of the vehicle by the driver.

[0047] The heating element 20, 21 , 22 is a resistive element. As an alternative, the heating element 20, 21 , 22 is a thermistor, preferably a positive temperature coefficient element with overheating protection means.

[0048] In an example the positive temperature coefficient element is having a first side and a second side. The first side is arranged in complimentary to the inner side of the suction port 70 and the second side is flooded by / in contact with the fluid for heating the fluid.

[0049] In the embodiments shown on [Figure 1] and [Figure 4], the heating element 20, 22 is for example a coating or an ink. The inner periphery / wall of the suction port 70 and / or the housing 111 is suitably adapted to have the printing of the ink or the coating of the heating element 20, 22.

[0050] As a variant, the heating element 20, 22 is a flexible film. The flexible film may be a strip like heating element with a heating side and a fixing side. The fixing side is attached with the inner periphery of the suction port 70 and / or the housing111 and the heating side is in contact with the fluid

[0051] In the embodiments shown on [Figure 2] and [Figure 3] the heating element 21 is a wire. In a non-limiting manner the wire is arranged in the form of a spiral or a coil with at least one turn. An axis of the coil is substantially coaxially arranged with the axis X1 of the suction port 70.

[0052] In the embodiment shown on [Figure 3] the heating element 21 is partly extended inside the suction inlet 72 adjacent to the rotating element 52. The suction inlet 72 is adapted to receive the heating element 21 extended adjacent to the rotating element 52. The heating element 21 is arranged in the suction port 70 and the suction inlet 72 in such a way that the heating element 21 is completely surrounded by the fluid .The fluid is heated by the heating element 21 and is thereby brought to a desired temperature. This can be done evenly andwith relatively little energy input in a short time due to arrangement of the heating element 21 in the length of the suction port 70.

[0053] Within the scope of the present invention, it is also possible that the heating element 20, 22 shown on the [Figure 4] is made of a wire.

[0054] As illustrated in [Figure 1], [Figure2], [Figure 3] and [Figure 4], an electric line 25 extend through the electric fluid pump 100a, 100b, 100c, 100d to electrically connect the control unit 30 and the heating element 20, 21 , 22.

[0055] In one example, the rotating element 52 of the pump unit 50 is, for instance, part of a gerotor. In another example the rotating element 52 of the pump unit 50 may be part of a gear pump or a vane pump or a centrifugal pump.

[0056] In all embodiment, the fluid is a lubricating oil. The electric fluid pump 100a, 100b, 100c, 100d circulates the lubricating oil for lubrication, cooling or actuation purpose of a vehicle transmission system.,

Claims

Claims

1. Electric fluid pump (100a, 100b, 100c, 10Od) 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) able to rotate about an axis of rotation X, a pump unit (50) which is in drive 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), wherein the electric fluid pump (100a, 100b, 100c) comprises a heating element (20, 21 ), characterized in that at least part of the heating element (20, 21 , 22) is arranged on the housing (111 ) around the pump unit (50) and / or 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 X1 and the heating element (20, 21 ) is arranged substantially coaxially with this axis X1 .

3. Electric fluid pump according to claim 1 or 2, characterized in that the heating element (22) is arranged on the inner or outer surface of the housing (111 ) around the pump unit (50) substantially coaxially with the axis X.

4. Electric fluid pump according to one of the preceding claims, characterized in that the heating element (20, 21 , 22) is a resistive element.

5. Electric fluid pump according to claim 4, characterized in that the heating element (20, 21 , 22) is a thermistor, notably a positive temperature coefficient element.

6. Electric fluid pump according to claim 4 or 5, characterized in that the heating element (20, 21 , 22) is a coating, an ink, a flexible film, a wire or a coil.

7. Electric fluid pump according to one of the preceding claims, characterized in that the heating element (20, 21 , 22) is arranged on at least 20% of the length of the at least one suction port (70) along the axis X1 .

8. Electric fluid pump according to one of the preceding claims, characterized in that an electric line (25) extend through the electric fluid pump (100a, 100b, 100c, 10Od) in order to electrically connect the control unit (30) and the heating element (20, 21 , 22).

9. 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 centrifugal.

10. Electric fluid pump according to one of the preceding claims, characterized in that the fluid is oil for lubrication, cooling or actuation purpose of a vehicle transmission system.

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

Images