Pump arrangement having temperature control components

Abstract

Pump arrangement (20) for conveying a fluid, with a housing (22), with a first rotatably mounted pump member (24), and with a second rotatably mounted pump member (26), wherein a fluid-conveying effect is produced by means of a relative rotary movement between the first and the second pump member (24, 26), wherein the first pump member (24) can be driven by an electric motor (42) which is arranged concentrically to the first pump member (24) and which has a stator (44) and a rotor (46), wherein the rotor (46) is fixed to the first pump member (24) and wherein the pump arrangement (20) is constructed in such a way that fluid is present in an annular gap (58) between the rotor (46) and the stator (44). In this case, the pump arrangement has temperature control means for heating the fluid in the annular gap (58).

Claims

1. A pump arrangement for delivering a lubricating fluid to a component of a motor vehicle, comprising: a housing; a first rotatably mounted pump member disposed in the housing; a second rotatably mounted pump member disposed in the housing, wherein a delivering effect of the lubricating fluid is produced by means of a relative rotary movement between the first and the second pump member; an electric motor arranged concentrically with the first pump member and which has a stator and a rotor, wherein the rotor is fixed to the first pump member for driving the first pump member; and an annular gap defined between the rotor and the stator for containing the lubricating fluid; wherein the rotor has a lower thermal conductivity than the first pump members; wherein the rotor is a ring element having a plurality of magnets and surrounds an outer circumference of the first pump member; wherein the ring element further includes a first heat insulating layer disposed radially between the magnets and the annular gap to define the annular gap between the inner surface of the stator and an outer surface of the first heat insulating layer for reflecting heat arising from the stator to hold the heat in the annular gap to heat the lubricating fluid in the annular gap to provide improved cold starting to the pump arrangement.

2. The pump arrangement as claimed in claim 1, wherein the stator has at least one stator pole on which an electric stator winding is arranged, and wherein the the at least one stator pole directly adjoins the annular gap.

3. The pump arrangement as claimed in claim 1, wherein the first pump member is produced from a metallic material.

4. The pump arrangement as claimed in claim 1, wherein the rotor generally has a ring shape.

5. The pump arrangement as claimed in claim 4, wherein the rotor has a plurality of magnets distributed over the circumference of the rotor.

6. The pump arrangement as claimed in claim 5, wherein a second heat insulating layer is disposed radially between the magnets and the first pump member.

7. The pump arrangement as claimed in claim 6, wherein the first and second heat insulating layers are comprised of one of a plastics material, a synthetic resin material or a ceramic material.

8. The pump arrangement of claim 5 wherein the first heat insulating layer is entirely disposed radially outwardly away from the plurality of magnets toward the gap.

9. The pump arrangement as claimed in claim 4, wherein the first pump member presents a plurality of internal teeth extending radially inwardly and the second pump member defines a plurality of external teeth extending radially outwardly for meshing with the internal teeth of the first pump member; the rotor includes a plurality of rotor magnet pole pairs disposed circumferentially about the rotor, and wherein the number of pole pairs of the rotor is equal to the number of internal teeth of the first pump member or to an integral multiple thereof.

10. The pump arrangement as claimed in claim 1, wherein the housing has a first housing section and a second housing section which are arranged on axially opposite sides of the pump members, and wherein one of the housing sections is formed by a circuit board arrangement that is fluidtight with respect to the interior of the housing.

11. The pump arrangement as claimed in claim 1, wherein the fluid contained in the annular gap is an oil.

12. The pump arrangement as claimed in claim 1, wherein the first and the second pump members form an annular gear pump.

13. The pump arrangement as claimed in claim 1, wherein at least one rotor position sensor is positioned directly on the stator.

14. The pump arrangement as claimed in claim 13, wherein the at least one stator pole includes a plurality of stator poles, and wherein the space between at least two of the plurality of stator poles of the stator is filled with an electrically insulating material.

15. The pump arrangement as claimed in claim 14, wherein the rotor position sensor is positioned directly on the stator between two of the stator poles.

16. A pump arrangement for conveying a lubricating fluid to a component of a motor vehicle, comprising: a housing; a gear pump rotatably supported in the housing and including a first pump member and a second pump member, wherein apumping effect of the lubricating fluid is produced in response to relative rotation between the first and second pump members; an electric motor adapted to rotatably drive the first pump member, the electric motor including a stator and a rotor, the stator being fixed to the housing and arranged concentrically with respect to the first pump member, the rotor being fixed to the first pump member and configured to define an annular gap with the stator, wherein the lubricating fluid is present in the annular gap between the stator and rotor, and wherein the rotor has a lower thermal conductivity than the first pump member; wherein the stator includes a stator core having a plurality of radially aligned stator poles, windings surrounding the stator poles, and an electrically insulating material provided between adjacent stator poles, and wherein the stator includes a cylindrical inner surface formed alternately by terminal ends of the stator poles and the electrically insulating material; wherein the rotor is a ring element having a plurality of magnets and surrounds an outer circumference of the first pump member; wherein the ring element further includes a first heat insulating layer disposed radially between the magnets and the annular gap to define the annular gap between the inner surface of the stator and an outer surface of the first heat insulating layer for reflecting heat arising from the stator to hold the heat in the annular gap to heat the lubricating fluid in the annular gap to provide improved cold starting to the pump arrangement.

17. The pump arrangement of claim 16 wherein the rotor position sensor is positioned directly on the stator between two of the stator poles.

18. The pump arrangement of claim 16 wherein the rotor further includes a second heat insulating layer disposed between the magnetic poles and the first pump member.

Description

DRAWINGS

(1) Illustrative embodiments of the invention are shown in the drawing and are explained in greater detail in the following description. In the drawing:

(2) FIG. 1 shows a schematic axial view of one embodiment of a pump arrangement according to the invention and a drive train of a motor vehicle in which a pump arrangement of this kind can be used;

(3) FIG. 2 shows a schematic detail view II of FIG. 1;

(4) FIG. 3 shows a schematic axial view of another embodiment of a pump arrangement according to the invention;

(5) FIG. 4 shows a schematic axial section through another embodiment of a pump arrangement according to the invention; and

(6) FIG. 5 shows a schematic development of a rotor and of a first pump member connected thereto to illustrate the field line profile within the first pump member given a suitable choice of the number of pole pairs and of teeth of the first pump member.

DETAILED DESCRIPTION

(7) FIG. 1 shows a drive train for a motor vehicle in schematic form denoted in general by 10. The drive train 10 comprises a drive motor 12, such as an internal combustion engine, a clutch arrangement 14 and a transmission arrangement 16 and a power split arrangement 18, by means of which the motive power can be distributed to driven wheels.

(8) In a drive train of this kind, it is necessary to deliver various fluids. This applies particularly to the oil for the internal combustion engine 12 and to the oil for a transmission 16.

(9) Furthermore, in a drive train 10 of this kind delivered fluid is fuel for an internal combustion engine.

(10) FIG. 1 shows in schematic form a pump arrangement 20 which is suitable for delivering such fluids, in particular for delivering fluids, the viscosity of which is highly temperature dependent, e.g. oil, especially transmission oil, such as ATF-oil or hypoid oil.

(11) The pump arrangement 20 comprises a housing 22, which is substantially circular in cross section. The pump arrangement 20 furthermore has a first pump member 24 and a second pump member 26. In the present case, the pump members 24, 26 form an annular gear pump or an gerotor pump, wherein the first pump member 24 forms an outer rotor and the second pump member 26 forms an inner rotor.

(12) The mode of operation of annular gear pumps or gerotor pumps of this kind is well known. Here, fluid is delivered from a schematically indicated suction port 28 to a schematically indicated discharge port 30 by initiating a relative rotary motion between the first and the second pump member 24, 26.

(13) The first pump member 24 is coaxial with a first axis 32. The second pump member 26 is coaxial with the second axis 34, wherein the axes 32, 34 are radially offset with respect to one another. In the present case, the first pump member 24 has internal teeth 36 and, in the present case, the second pump member 26 has external teeth 38, wherein the internal teeth 36 and the external teeth 38 mesh in the manner of an annular gear pump. In particular, the tooth flanks of the internal teeth 36 and of the external teeth 38 are in the form of circular arcs or trochoids. In the present case, the first pump member 24 has seven teeth, between which an identical number of outer kidney shaped recesses is formed. The second pump member 26 has one tooth less and thus has six teeth and an identical number of kidney shaped recesses.

(14) The second pump member 26 is supported rotatably on the housing 22. The support is indicated schematically by 40 in FIG. 1.

(15) The pump arrangement 20 furthermore comprises an electric motor 42. The electric motor 42 has a stator 44 and a rotor 46. The stator 44 is fixed on the housing 22 and is arranged concentrically to the first pump member 24. The stator 44 comprises a stator core 48, on which a plurality of substantially radially aligned stator poles 50 are formed. Respective windings 52 are fixed on the stator poles 50. In the present case, the number of stator poles is 12.

(16) The regions between the stator poles 50 and the windings 52 contained therein are filled with an electrically insulating material 54, which can be formed by plastic or by synthetic resin, for example.

(17) The rotor 46 comprises a plurality of magnet poles 56, in the present case 14 magnet poles, which are arranged in a manner distributed over the circumference and are preferably magnetized radially. In this case, the rotor 46 is preferably designed as a ring element and is arranged on the outer circumference of the first pump member 24 and connected to the latter for conjoint rotation, e.g. by press fitting, by adhesive bonding or similar.

(18) An annular gap 58 is set up between the rotor 46 and the stator 44. The design of the pump arrangement 20 is such that the fluid to be delivered between the pump members 24, 26 is also situated in the annular gap 58. This makes it possible to avoid complex seals in the region of the annular gap.

(19) The stator 44 is designed in such a way that the stator poles 50 thereof directly adjoin the annular gap 58. Consequently, the inner circumference of the stator is formed alternately by stator poles 50 and electrically insulating material 54. This inner surface is designed or machined in such a way that it can form a kind of sliding bearing for the rotor 46.

(20) At least one rotor position sensor 60, by means of which the rotor position can be detected, is provided in the region between two stator poles 50.

(21) FIG. 1 furthermore schematically illustrates a control device 62, which is designed to control the drive train 10 and/or the pump arrangement 20. It is self-evident that the rotor position sensor 60 can be connected to a control device 62 of this kind.

(22) During the operation of the pump arrangement 20, the electric motor 42 is operated in such a way that the rotor 46 rotates together with the first pump member 24 in a direction of rotation 64 relative to the housing 22 and the second pump member 26, as indicated at 64. Thereby, a delivery effect of the fluid from the suction port 28 to the discharge port 30 is initiated.

(23) FIG. 2 shows a detail view II of FIG. 1.

(24) It can be seen here that the rotor 46 is formed by a plurality of magnets 56, on the radial outer side of which a first heat insulating layer 66 is formed and on the radially inner side of which a second heat insulating layer 68 is formed.

(25) At low temperatures, such as those which can occur in motor vehicle drive trains, fluid present in the annular gap 58 can have a very high viscosity, with the result that the cold starting behavior in the case of prior art gerotor pumps can be problematic.

(26) In the present case, the heat which arises in the windings 52 during a cold start is passed into the stator poles 50 and, from there, is fed directly to the fluid in the annular gap 58, with the result that the latter warms up quickly, thereby reducing the viscosity.

(27) By means of the first heat insulating layer 66 and/or by means of the second heat insulating layer 68, it is furthermore achieved that the heat remains substantially in the annular gap 58 and is not dissipated directly to the first pump member 24 and to fluid in contact therewith. This too leads to rapid heating of the fluid in the annular gap, thus, improving the cold starting behavior of the pump arrangement 20.

(28) FIG. 3 shows an alternative embodiment of a pump arrangement 20, which corresponds in general terms as regards construction and operation to the pump arrangement 20 in FIGS. 1 and 2. Identical elements are therefore denoted by identical reference signs. In the following the differences are mainly explained.

(29) In the present case, the pump arrangement 20 is designed in such a way that the first pump member 24 is the inner rotor and the second pump member 26 is the outer rotor. In this case, the electric motor is arranged concentrically with the inner rotor 24, while, in this case, the electric motor 47 is designed as an external rotor motor, which has a stator 44 situated radially on the inside and a rotor 46 situated radially on the outside. In this case too, temperature control means for the rapid heating of the fluid in the annular gap 58 can be designed identically or in a similar way to those described above with reference to FIGS. 1 and 2.

(30) FIG. 4 shows another alternative embodiment of a pump arrangement 20, which can correspond in general terms as regards construction and operation to one of the pump arrangements in FIGS. 1 to 3. Identical elements are therefore denoted by identical reference signs. In the following the differences are mainly explained.

(31) The pump arrangement 20 in FIG. 4 comprises a housing 22, which has a first housing section 72. The first housing section 72 comprises a radial section 74, which is arranged on one axial side of the pump arrangement. Furthermore, the first housing section 72 has a substantially cylindrical axial section 76, which is connected integrally to the radial section 74 and surrounds the pump arrangement at the outer circumference.

(32) Furthermore, the housing 22 has a second housing section 78, which is arranged on the axially opposite side of the pump arrangement and is connected in the manner of a cover to the first housing section 72 in order to surround the pump arrangement in a fluid-tight manner.

(33) In the present case, the second housing section 78 is designed as an electric circuit board arrangement, which can be produced from a material such as FR4 or ceramics. The circuit board arrangement is configured so as to be fluid-tight with respect to the interior of the housing 22. Here, the circuit board arrangement 78 preferably forms an axial running surface for the pump members 24, 26.

(34) It is furthermore shown in FIG. 4 that a rotor position sensor 60, which is embedded in an electrically insulating material 54, can be connected directly to the circuit board arrangement 78. As an alternative, it is possible to integrate a rotor position sensor 60 into the circuit board arrangement 78.

(35) Electronic components can be provided on the axially outer side of the circuit board arrangement 78, as indicated schematically at 80.

(36) At the same time, the circuit board arrangement 80 can also comprise power-carrying components, such as power transistors for example. These can preferably be arranged on the circuit board arrangement 78 in such a way that they are connected in the circumferential direction and/or in the radial direction with the spatial zone of the pump arrangement in which the fluid is delivered from the suction port to the discharge port. Thereby, the fluid can contribute to the cooling of the electronic or electric components on the circuit board arrangement 78. It is furthermore possible to improve the cold starting behavior of the pump arrangement since the heat of the electronics can contribute to heating the fluid.

(37) The electric components 80 can also be integrated into such a circuit board, this preferably being designed with buried wires.

(38) FIG. 5 shows a schematic development of the rotor 46 and of the first pump member 24 connected thereto in FIGS. 1 and 2.

(39) The number of magnets 56 corresponds here to the number of teeth of the first pump member 24. The poles of the magnets are each arranged in the region of a tooth base of the internal teeth 36. In the first pump member 24, this leads to a field line profile between the adjacent permanent magnets of the kind indicated by way of example as a single field line 84 in FIG. 5. Substantially, the field line profile 84 coincides with the profile of the contour of a tooth of the internal teeth 36, with the result that the magnetic resistance is minimized and consequently a high efficiency can be obtained from the electric motor 42. In this arrangement of the first pump member 24 and rotor 46 in FIG. 5, the number of pole pairs of the rotor is thus equal to the number of teeth of the first pump member. The number of pole pairs could also be twice this or preferably an integral and, in particular, even-numbered multiple thereof. In this case too, the advantage described above would be achieved as before, although possibly not in this form.