LIQUID PUMP, IN PARTICULAR FOR PROVIDING A SUPPLY TO A TRANSMISSION OF AN ELECTRIC OR HYBRID DRIVE MODULE OF A MOTOR VEHICLE

Abstract

A liquid pump, in particular for providing a supply to a transmission of an electric or hybrid drive module of a motor vehicle, having a pump housing wherein a pump chamber and a pump rotor are arranged, wherein the pump chamber is connected to an outlet channel to which a temperature sensor is assigned, wherein the temperature sensor has a lead frame and an SMD sensor element.

Claims

1. A liquid pump for providing a supply to a transmission of an electric or hybrid drive module of a motor vehicle, said liquid pump comprising a pump housing wherein a pump chamber and a pump rotor are arranged, wherein the pump chamber is connected to an outlet channel to which a temperature sensor is assigned, wherein the temperature sensor has a lead frame and an SMD sensor element.

2. The liquid pump according to claim 1, wherein the lead frame is provided on the side facing away from the SMD sensor element with two press-in contacts, which are pressed into openings in a circuit board.

3. The liquid pump according to claim 2, wherein the circuit board carries the control electronics of the liquid pump.

4. The liquid pump according to claim 1, wherein the lead frame has a plastic bridge between the SMD sensor element and the press-in contacts.

5. The liquid pump according to claim 1, wherein the SMD sensor element has a plastic encapsulation.

6. The liquid pump according to claim 5, wherein the plastic encapsulation of the SMD sensor element extends to just before the press-in contacts.

7. The liquid pump according to claim 1, wherein the plastic encapsulation has a sealing flange which bears sealingly against the pump housing.

8. The liquid pump according to claim 7, wherein the sealing flange has a groove wherein an O-ring seal is arranged.

9. The liquid pump according to claim 7, wherein the sealing flange is clamped between the pump housing and a control housing.

10. The liquid pump according to claim 1, wherein provision is made of a control housing which is attached to the pump housing, and wherein the control housing is provided with a protuberance which projects into the outlet channel, wherein the SMD sensor element is arranged within the protuberance.

11. The liquid pump according to claim 9, wherein the control housing, including the protuberance, is filled with a potting compound.

12. The liquid pump according to claim 10, wherein the pump housing has an opening for the protuberance, the inner diameter of which opening is larger than the outer diameter of the protuberance.

Description

[0034] FIGS. 1 and 2 show a liquid pump 2 according to a first embodiment. It may serve for delivering hydraulic fluid which is supplied to a transmission of an electric or hybrid drive module of a motor vehicle, for example for lubrication of bearing points.

[0035] The liquid pump 2 may be attached to a transmission housing 4 for example by means of fastening screws 3 and directly suck hydraulic fluid from the transmission housing 4 through a filter 5. Said hydraulic fluid may then be removed via an outlet channel 6.

[0036] In the exemplary embodiment shown, the outlet channel 6 of the liquid pump 2 leads directly to a supply channel 7 which is integrated into the transmission housing 4. Alternatively, the liquid pump 2 could also have an outlet connector situated outside the transmission housing 4, in order to pass on the delivered hydraulic fluid through pipes or hoses.

[0037] The liquid pump 2 has a pump housing 10 with a pump chamber 11 in which a pump rotor 12 is arranged. The pump rotor 12 is coupled to a motor rotor 16 via a motor shaft 14.

[0038] In the embodiment shown, the pump rotor 12 meshes in an outer ring 18 which slides in the pump housing 10. Said liquid pump is therefore a toothed ring pump, also known as a “gerotor pump”.

[0039] The specific configuration of the rotor is however of no further relevance here. Use could also be made of a rotor which functions according to the principle of a centrifugal pump.

[0040] A control housing 20 having inter alia a stator 22 and a circuit board 24 is attached to the pump housing 10.

[0041] Together with the motor rotor 16, the stator 22 forms the drive motor of the liquid pump.

[0042] The circuit board 24 carries various electronic components which serve for activation of the drive motor formed inter alia by the components 14, 22.

[0043] A temperature sensor 26 (see also FIGS. 3 to 6) is integrated into the liquid pump 2. Specifically, the temperature sensor 26 is assigned here to the outlet channel 6, so that the temperature of the hydraulic fluid on the pressure side of the liquid pump 2 can be detected.

[0044] The temperature sensor 26 has a lead frame 28, which is formed here by two conductor sections composed of metal that extend in a substantially parallel manner. An SMD sensor element 30 is attached to the lead frame 28 at one end. As can be seen in particular in FIG. 6, the SMD sensor element 30 is supported in a planar manner on the lead frame 28.

[0045] That end of the lead frame which is situated opposite the SMD sensor element 30 is in the form of two press-in contacts 32.

[0046] The temperature sensor 26 furthermore has a plastic encapsulation 34, which extends here from the region of the SMD sensor element 30 to just before the press-in contacts 32. As can be seen in particular in FIGS. 3 to 5, the plastic encapsulation 34 has a head-like section 36 which surrounds the SMD sensor element 30. In the direction towards the press-in contacts 32, the plastic encapsulation 34 is formed in the manner of a plastic bridge which fixes the two conductor sections of the lead frame 28 at a precise distance from one another.

[0047] A material having good heat conduction properties is used for the plastic encapsulation 34, so that the SMD sensor element 30 responds quickly to changes in the temperature on the outer side of the head-like section 36.

[0048] At the crossover from the head-like section 36 to the plastic bridge, the plastic encapsulation 34 has a sealing flange 38 which extends in a plane perpendicular to the longitudinal axis of the two conductor sections of the lead frame 28. A circumferential groove 40 intended for receiving an O-ring seal is provided on the side facing the SMD sensor element 30.

[0049] The temperature sensor 26 is fitted in the liquid pump 2 in such a way that the SMD sensor element 30 is situated within the outlet channel 6 (see FIGS. 1 and 2). For this purpose, the pump housing 10 has an opening through which the head-like section 36 extends. Here, the sealing flange 38 is clamped between the pump housing 10 and the control housing 20. An O-ring seal arranged in the groove 40 provides for liquid-tight sealing at this point.

[0050] As an alternative to an O-ring, use may also be made of moulded-on sealing lips.

[0051] The temperature sensor 26 is pressed, by way of its press-in contacts 32, into suitable openings in the circuit board 24 in such a way that the sealing flange 38 comes to bear on a support surface 44 of the control housing 20, which support surface faces the pump housing 10.

[0052] The control housing 20 may have an inwardly extending supporting wall 46 which guides the temperature sensor 26.

[0053] In the exemplary embodiment shown, the interior of the control housing 20 is filled with a potting compound 48 such that all the components (including the stator 22, the circuit board 24 and those sections of the temperature sensor 26 which extend into the control housing 20) are fixed rigidly therein.

[0054] FIGS. 7 to 10 show a second embodiment of the liquid pump. The same reference signs are used for the components known from the first embodiment, and, in this respect, reference is made to the explanations above.

[0055] The difference between the first and second embodiments is that, in the second embodiment, the control housing has a protuberance 50 which extends into the outlet channel 6 through an opening 52 in the pump housing 10. The temperature sensor 26, in particular the SMD sensor element 30, is arranged within the protuberance 50, so that the temperature sensor is separated by means of a (thin) wall of the control housing 20 from the outlet channel 6 and the hydraulic fluid situated therein.

[0056] As can be seen in FIGS. 8 to 10, for the temperature sensor according to the second embodiment, the plastic encapsulation 34 is formed only as a plastic bridge which fixes the two conductor elements of the lead frame 28 at a distance from one another and parallel to one another. The SMD sensor element 30 is exposed at the front end of the lead frame 28.

[0057] In the second embodiment too, the temperature sensor 26 is pressed into suitable openings in the circuit board 24. The supporting wall 46 serves for guidance. In the second embodiment too, the control housing 20 is completely filled with a potting compound 48 which conducts heat well. The potting compound 48 is situated even within the protuberance 50, with the result that the SMD sensor element 30 is separated thermally from the hydraulic fluid flowing through the outlet channel 6 only by the potting compound and the thin wall of the protuberance 50 of the control housing 20.

[0058] Since the protuberance 50 extends freely through the opening 52 of the pump housing 10, hydraulic fluid flows around the protuberance 50 on all sides, with the result that the SMD sensor element 30 can respond quickly to any changes in the temperature of the hydraulic fluid.

[0059] FIG. 12 shows a temperature sensor according to a further embodiment. The same reference signs are used for the components known from the preceding embodiments, and, in this respect, reference is made to the explanations above.

[0060] The difference between the third embodiment and the preceding embodiments is that, in the third embodiment, the temperature sensor 30 is connected to the lead frame 28 via two contact wires 60. The contact wires 60 perform both the function of electrical connection of the temperature sensor 30 and the function of mechanical fixing of same until this is potted in the control housing in the same manner as the temperature sensor in the second embodiment.