Fluid pump with embedded heat dissipating plate

Abstract

A fluid pump, in particular an oil pump for supplying a clutch actuator, a gearbox actuator, a lubrication system and/or a cooling system of a drive train. The fluid pump includes a housing, a stator, a control unit which is arranged at one end of the housing, and a heat-conducting element with a plate-like base body. The stator, the control unit and the plate-like base body are embedded in a casting compound.

Claims

1. A fluid pump, for supplying a clutch actuator, a gearbox actuator, a lubrication system and/or a cooling system of a drive train, comprising: a housing, an electric drive unit which comprises a stator and a rotor which is arranged inside the stator and can rotate about a rotor axis, a control unit with a printed circuit board which is arranged at one end of the housing, and a heat-conducting element with a plate-like base body, wherein: the heat-conducting element is arranged on a side of the printed circuit board which faces away from the stator, and the stator, the control unit and the plate-like base body are embedded in a casting compound.

2. The fluid pump according to claim 1, wherein the plate-like base body has a surface area which is more than 50% of an internal cross-section of the housing.

3. The fluid pump according to claim 2, wherein the plate-like base body is provided with support tabs which bear elastically against the control unit.

4. The fluid pump according to claim 2, wherein the plate-like base body bears directly against at least one electronic component of the control unit.

5. The fluid pump according to claim 2, wherein a layer of the casting compound is situated between at least one electronic component of the control unit and the plate-like base body.

6. The fluid pump according to claim 2, wherein the plate-like base body is provided with a plurality of spacers which bear against a printed circuit board of the control unit.

7. The fluid pump according to claim 2, wherein the plate-like base body is provided with a plurality of through openings.

8. The fluid pump according to claim 2, wherein the plate-like base body has at least one embossed raised/depressed portion which has a different spacing from a printed circuit board of the control unit than the remainder of the plate-like base body.

9. The fluid pump according to claim 2, wherein the plate-like base body is made from an aluminium alloy.

10. The fluid pump according to claim 2, wherein the housing is made from an aluminium alloy.

11. The fluid pump according to claim 1, wherein the plate-like base body is provided with support tabs which bear elastically against the control unit.

12. The fluid pump according to claim 11, wherein the heat-conducting element and the housing are electrically conductive.

13. The fluid pump according to claim 11, wherein the plate-like base body bears directly against at least one electronic component of the control unit.

14. The fluid pump according to claim 1, wherein the plate-like base body bears directly against at least one electronic component of the control unit.

15. The fluid pump according to claim 1, wherein a layer of the casting compound is situated between at least one electronic component of the control unit and the plate-like base body.

16. The fluid pump according to claim 1, wherein the plate-like base body is provided with a plurality of spacers which bear against the printed circuit board of the control unit.

17. The fluid pump according to claim 1, wherein the plate-like base body is provided with a plurality of through openings.

18. The fluid pump according to claim 1, wherein the plate-like base body is made from an aluminium alloy.

19. The fluid pump according to claim 1, wherein the housing is made from an aluminium alloy.

Description

(1) The invention will be described below on the basis of two embodiments which are illustrated in the appended drawings, in which:

(2) FIG. 1 shows a fluid pump according to the invention in a perspective view;

(3) FIG. 2 shows a cross-section through the fluid pump from FIG. 1;

(4) FIG. 3 shows a plan view of the cast body of the fluid pump in FIGS. 1 and 2;

(5) FIG. 4 shows a section along the plane IV-IV of FIG. 3;

(6) FIG. 5 shows a heat-conducting element of the fluid pump according to a first embodiment in a perspective view;

(7) FIG. 6 shows a schematic exploded view of a fluid pump according to the first embodiment, wherein the cast body is illustrated in section;

(8) FIG. 7 shows a heat-conducting element of a fluid pump according to a second embodiment in a perspective view; and

(9) FIG. 8 shows a schematic exploded view of the fluid pump according to the second embodiment.

(10) A fluid pump 10, which has a housing 12 in which a stator 14 (see FIG. 2) and a control unit 16 are arranged, is shown in FIG. 1. The control unit 16 is used to activate the stator such that a rotor 18 can be set in rotation in a desired fashion.

(11) The rotor 18 is part of a pump module which has a pump unit 20, driven by the rotor 18, by means of which a fluid can be pumped through suction and pressure ports 22 shown schematically in FIG. 1.

(12) The pump module with the pump unit 20 and the rotor 18 is attached to the housing 12 from outside such that the rotor 18 lies inside the stator 14.

(13) A cap 24 which delimits the space relative to the rotor 18 is arranged inside the housing 12. The internal volume between the wall of the housing 12 and the cap 24 is filled with a casting compound 26. In addition to the stator 14 and the control unit 16, a heat-conducting element 30 is also embedded in the casting compound 26 and thus in the cast body 28 formed by the set casting compound 26.

(14) The heat-conducting element 30 (see in particular FIG. 5) has a plate-like base body 32 which is here designed as plane.

(15) Provided in the vicinity of the outer rim of the base body 32 are a plurality of spacers 34 which are here designed in the form of beads which extend along almost the whole outer circumference of the base body.

(16) The heat-conducting element 30 here extends over almost the whole cross-section of the housing 12.

(17) Provided at the outer rim of the base body 32 of the heat-conducting element 30 are a plurality of support tabs 36 which are provided and dimensioned so as to bear against the inner side of the housing 12 under pretension (see FIG. 2).

(18) The heat-conducting element 30 is attached to a printed circuit board 38 of the control unit 16 before the housing 12 is filled with the casting compound 26, and to be precise such that the spacers 34 are supported on the printed circuit board 38. It is consequently ensured that the base body 32 of the heat-conducting element 30 is situated with a desired predefined spacing from electronic power components 40 which are part of the control unit 16.

(19) As can be seen in FIG. 2, the heat-conducting element 30 is arranged on that side of the printed circuit board 38 which faces away from the stator 14.

(20) The support tabs 36 can be used to install the heat-conducting element 30 at the desired position inside the housing 12 and bearing against the printed circuit board 38 of the control unit 16. Depending on the component heights of the electronic power components 40 of the control unit 16 (and also depending on any raised/depressed portions which are embossed in the base body 32 of the heat-conducting element 30), the electronic power components 40 bear directly against the heat-conducting element 30 or a small gap is present between the upper side of the power components 40 and the underside of the base body 32 of the heat-conducting element 30.

(21) If the interior of the housing 12 is filled with the casting compound 26, the space between the printed circuit board 38 and the heat-conducting element 30 is also filled. A quantity of casting compound 26 is added here such that the level of the casting compound is above the heat-conducting element 30 such that the latter is completely embedded. As can be seen in FIGS. 1 and 2, however, the heat-conducting element 30 is situated with a slight spacing below the end face of the cast body 28 thus formed.

(22) Heat from the electronic power components 40 is transmitted into the base body 32 either by direct contact with the base body 32 (see the relieved portion, labelled with the reference sign 50 in FIG. 6, in the cast body 28) or via a residual thin layer of casting compound 26 (see the relieved portion, labelled with the reference sign 52 in FIG. 6, of a power component).

(23) The heat introduced locally from the power components 40 is transmitted over the whole surface area of the heat-conducting element 30 by virtue of the high thermal conductivity of the heat-conducting element 30. Some of the heat is emitted into the environment via the outer end side of the cast body 28, and some of the heat is emitted into the housing 12 via the support tabs 36. Relatively large amounts of heat can be effectively dissipated into the environment without there being any need for heat sinks to be provided which have to extend through the cast body 28 to the outside.

(24) A further advantage of the heat-conducting element 30 which is electrically conductively connected to the housing 12 is that it improves the EMC properties of the pump because it serves as a shield.

(25) FIGS. 7 and 8 show a second embodiment. The same reference signs are used for the features and components known from the first embodiment, and to this extent reference is made to the explanations above.

(26) The difference between the first and the second embodiment is that, in the second embodiment, the base body 32 is designed as not closed and instead has a plurality of perforations or through openings 60. Material bridges of casting compound extend through the through openings 60 such that those sections of the cast body 28 which are situated above and below the heat-conducting element 30 are connected directly to one another. This is advantageous for the strength of the cast body 28.

(27) In terms of avoiding notch effects, the rims of the through openings 60 are designed as very smooth and in particular with a rounded bevel.