LIQUID PUMP, IN PARTICULAR FOR A COMPONENT OF A DRIVE TRAIN OF A MOTOR VEHICLE

Abstract

A liquid pump having an electric motor, a pump assembly, which is driven by the electric motor, and a housing wherein the electric motor and the pump assembly are arranged, wherein the housing is in the form of a one-piece, injection-moulded pot having a base and side walls, wherein the pump assembly bears against the base, and the electric motor is arranged on the open side of the housing remote from the base.

Claims

1. A liquid pump comprising an electric motor, a pump assembly, which is driven by the electric motor, and a housing in which the electric motor and the pump assembly are arranged, wherein the housing is in the form of a one-piece, injection-moulded pot having a base and side walls, wherein the pump assembly bears against the base and the electric motor is arranged on the open side of the housing remote from the base.

2. The liquid pump according to claim 1, wherein an intake opening and/or a discharge opening of the liquid pump is arranged in the base of the housing.

3. The liquid pump according to claim 2, wherein a sealing structure is associated with the opening in the base of the housing.

4. The liquid pump according to claim 1, wherein the pump assembly has a pump housing which bears against the base.

5. The liquid pump according to claim 4, wherein the pump housing is centred in the housing.

6. The liquid pump according to claim 4, wherein the pump housing is fixedly connected to the housing.

7. The liquid pump according to claim 1, wherein there is provided a separating pot which extends between a stator and a rotor of the electric motor and separates a hydraulic side of the liquid pump from a dry side such as electronics side.

8. The liquid pump according to claim 7, wherein the separating pot has a flange which is connected to the housing.

9. The liquid pump according to claim 8, wherein the flange is fixedly connected to the housing.

10. The liquid pump according to claim 8, wherein the flange bears against the pump housing.

11. The liquid pump according to claim 7, wherein the separating pot is formed by a pipe socket which is formed in one piece with the housing, and a separating cover which is sealingly connected to the end face of the pipe socket.

12. The liquid pump according to claim 1, wherein a printed circuit board is arranged on the open side of the housing remote from the base, which printed circuit board is encapsulated by potting compound in the housing together with the stator.

13. The liquid pump according to claim 1, wherein screw openings are integrated into the base of the housing.

14. The liquid pump according to claim 1, wherein screw openings spaced apart from the base in the axial direction are provided.

15. The liquid pump according to claim 1, wherein the pump assembly is a gear ring pump.

16. The liquid pump according to claim 2, wherein a sealing groove or a cylindrical surface is associated with the opening in the base of the housing.

17. The liquid pump according to claim 4, wherein the pump housing is welded or screwed to the housing.

18. The liquid pump according to claim 8, wherein the flange is welded, adhesively bonded, screwed or riveted to the housing.

19. The liquid pump according to claim 8, wherein the flange bears against the pump housing and is centred in the pump housing.

20. The liquid pump according to claim 1, wherein the pump assembly is a gerotor pump.

Description

[0024] The invention will be described below on the basis of various embodiments, which are illustrated in the appended drawings. In these drawings:

[0025] FIG. 1 shows a plan view of a liquid pump according to a first embodiment of the invention;

[0026] FIG. 2 shows a section along the plane II-II in FIG. 1;

[0027] FIG. 3 shows the detail III in FIG. 2 on an enlarged scale;

[0028] FIG. 4 shows a perspective view from below of the liquid pump in FIG. 1;

[0029] FIG. 5 shows a view from below of the liquid pump in FIG. 1;

[0030] FIG. 6 shows a sectional view along the plane VI-VI in FIG. 5;

[0031] FIG. 7 shows the detail VII in FIG. 6 on an enlarged scale;

[0032] FIG. 8 shows a perspective plan view of the liquid pump in FIG. 1;

[0033] FIG. 9 shows a perspective view from below of a second embodiment of the invention;

[0034] FIG. 10 shows a cross section through a liquid pump according to a third embodiment;

[0035] FIG. 11 shows a cross section through a liquid pump according to a fourth embodiment;

[0036] FIG. 12 shows a cross section through a liquid pump according to a fifth embodiment;

[0037] FIG. 13 shows a cross section through a liquid pump according to a sixth embodiment;

[0038] FIG. 14 shows part of a cross section through a liquid pump according to a seventh embodiment;

[0039] FIG. 15 shows part of a cross section through a liquid pump according to an eighth embodiment;

[0040] FIG. 16 shows part of a cross section through a liquid pump according to a ninth embodiment;

[0041] FIG. 17 shows part of a cross section through a liquid pump according to a tenth embodiment.

[0042] FIGS. 1 to 8 show a first embodiment of the liquid pump. It serves to provide a stream of hydraulic oil for a drive train of a motor vehicle. This stream can be used to lubricate or to cool components of the drive train. The stream of hydraulic oil can also be provided to be converted in actuators into an actuating stroke, for example in order to shift a clutch.

[0043] The liquid pump has a housing 10 which is formed in one piece and has a pot shape, that is to say has a base 12 and side walls 14. The housing 10 is an injection-moulded part composed of plastic.

[0044] If higher strengths are required, the housing 10 can also be produced from other materials. One example is a housing composed of an aluminium alloy, which is machined at least in some portions.

[0045] Arranged in the housing 10 are a pump assembly and an electric motor.

[0046] The pump assembly has a pump housing 16 and a pump rotor 18 received therein. In the embodiment of the liquid pump shown here, there is further present an outer ring 20 which is rotatably received in the pump housing 16.

[0047] The liquid pump is here a pump of the gerotor pump type. Other types of pump are in principle also possible.

[0048] The electric motor has a rotor 22 and a stator 24. The stator 24 is stationarily arranged in the housing 10 against the side walls 14. The rotor 22 is connected in a rotationally fixed manner to a shaft 26 which is rotatably mounted in an opening of the pump housing 16. The pump rotor 18 is attached in a rotationally fixed manner to the end of the shaft 26 that is located inside the pump housing 16.

[0049] The pump housing 16 is of a size such that the pump rotor 18 can be received therein with the necessary axial play.

[0050] The pump housing 16 is centred in the interior of the housing 10 by means of radially protruding centring lugs 17 (see in particular FIG. 3), which bear against the inner wall of the housing 10. In order to avoid accumulations of material there, which can be the cause of shrinkage problems on injection moulding, the centring lugs are hollow. In this manner, a certain resilience in the radial direction is also ensured, which assists with centring.

[0051] There is provided a separating pot 28 which separates the hydraulic oil side of the pump from the electronics side. The separating pot 28 here has a flange 30, a side wall 32 of circular cylindrical cross section, and an end wall 34.

[0052] The separating pot 28 is an injection-moulded part composed of plastic, which has a wall thickness at least in the region of the side wall 32, which extends between the rotor 22 and the stator 24, in the order of 0.3 mm.

[0053] There can be used for the housing 10, the pump housing 16 and the separating pot 28 in particular thermoplastics and/or thermosetting plastics. Particularly suitable materials are PPA or PPS.

[0054] The pump assembly and the electric motor are mounted into the interior of the housing 10 from the open side thereof. The pump housing 16 thereby bears against the inner side of the base 12, and the flange 30 of the separating pot 28 presses on a circumferential contact collar 36, which is formed in one piece with the pump housing 16. The flange 30 itself is welded to the housing 10, namely to a welding collar 38 protruding in the axial direction (see in particular FIG. 3).

[0055] In order to press the pump housing 16 in the axial direction against the base 12 of the housing 10, to fix the pump housing 16 in the housing 10 and at the same time to ensure a reliable seal between the hydraulic oil side and the electronics side, the flange 30 of the separating pot 28 is welded to the welding collar 38 of the housing 10. An ultrasonic welding method, for example, can be used for this purpose.

[0056] It can be seen in FIG. 3 that the flange 30 has a groove 40 in which the welding collar 38 is positioned. The dimensions of the components relative to one another in the axial direction are such that the flange 30 presses the pump housing 16 against the base 12 of the housing 10 via the contact collar 36 and is reliably welded to the welding collar 38 before the contact collar 36 bears against the contact shoulder 42, visible in FIG. 3, of the housing 10.

[0057] On mounting of the liquid pump, the pump housing 16, on which the pump rotor 18 and the rotor 22 of the electric motor are mounted, is inserted into the interior of the housing 10. The flange 30 of the separating pot 28 is then pressed against the welding collar 38 and welded there. During this operation, the welding collar 38 is compressed in the axial direction until the pump housing 16 is pressed with its end face firmly against the base 12 of the housing 10 via the contact collar 36, which bears against the flange 30 of the separating pot 28. The weld expulsion thereby formed can be received without difficulty in the groove 40 of the flange 30.

[0058] In the welded state, the hydraulic side of the pump is reliably separated from the electronics side owing to the welded connection between the welding collar 38 and the flange 30, without the need for further seals on the housing.

[0059] On welding of the flange 30 to the welding collar 38, there can be used in principle any suitable welding method with which two weldable plastics can be connected together. Examples are a laser welding method, an ultrasonic welding method and a friction welding method.

[0060] Once the separating pot 28 has been welded to the housing 10, the stator 24 can be inserted, and there is mounted on the stator a printed circuit board 44, starting from which the coils of the stator 24 of the electric motor are electrically contacted.

[0061] In FIG. 2 there is also shown an insertion channel 46 for an electrical connector plug with which the liquid pump is electrically contacted.

[0062] After the printed circuit board has been mounted, the region of the housing in which the stator 24 and the printed circuit board 44 are arranged is filled with a potting compound. This serves on the one hand as mechanical support for the separating pot 28, and on the other hand as material for dissipating thermal losses of the stator 24.

[0063] In the base 12 of the housing 10 there are also arranged an intake opening 48 and a discharge opening 50, which open in the interior of the housing 10 in the region in which the pump unit is located. As can be seen, for example, in FIG. 6, the intake opening 48 and the discharge opening 50 extend in the axial direction through the base 12 of the housing 10.

[0064] In the embodiment of FIGS. 1 to 8, each opening has an associated sealing ring 52, which is arranged in a sealing groove 54.

[0065] For the attachment of the liquid pump, multiple screw openings 56 are integrated in one piece into the housing. In the exemplary embodiment shown, these screw openings are integrated into the base 12, so that the liquid pump can be screwed directly to a transmission housing, for example. The seals 52 thereby seal against the transmission housing in the axial direction, and the liquid pump draws from the transmission housing directly, without the need for a separate storage container and corresponding lines.

[0066] In this manner, reliable sealing and high security against the undesirable escape of hydraulic oil are ensured with a minimum number of seals, namely exactly two seals.

[0067] FIG. 9 shows a second embodiment of the invention. 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.

[0068] The difference between the second and the first embodiment is that, in the second embodiment, there is used instead of two separate seals 52 a single seal 52, which has a separating web 53 which separates the intake opening 48 from the discharge opening 50.

[0069] FIG. 10 shows a third embodiment of the liquid pump. The same reference signs are used for the components known from the first two embodiments, and, in this respect, reference is made to the explanations above.

[0070] The difference between the third and the preceding embodiments is that, in the third embodiment, an axially acting seal which is arranged in a sealing groove 54 is provided for the intake opening 48, while a cylindrical sealing surface 58 is provided for the discharge opening 50, so that a radial seal is formed.

[0071] FIG. 11 shows a fourth embodiment of the liquid pump. 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.

[0072] The difference between the fourth and the third embodiments is that, in the fourth embodiment, a radial seal is used for the intake opening 48 instead of an axial seal. For this purpose, a stepped, cylindrical outer surface 59 is formed on a connecting piece 60 which is formed in one piece with the base 12.

[0073] FIG. 12 shows a fifth embodiment of the liquid pump. 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.

[0074] The difference between the first and the fifth embodiments is that, in the fifth embodiment, the screw openings 56 are not arranged at the level of the base 12 but are set back slightly in the axial direction towards the open side of the housing 10. In the exemplary embodiment shown, the screw openings 56 are located at approximately half the height of the housing 10.

[0075] FIG. 13 shows a sixth embodiment of the liquid pump. 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.

[0076] The sixth embodiment differs from the fifth and the first embodiment in that the screw openings 56 are now arranged at the height of the open end of the housing 10. Sealing in the region of the intake opening 48 and the discharge opening 50 still takes place in the axial direction, in that the housing 10 is pressed in the axial direction from the plane of the screw openings 56 in the direction towards the base 12 against a counter-surface. The housing 10 can be inserted in the manner of a cartridge into, for example, a suitably configured receiving opening and can be fixedly screwed there.

[0077] FIG. 14 shows a seventh embodiment of the liquid pump. 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.

[0078] The difference between the seventh embodiment and the preceding embodiments is that, in the seventh embodiment, the flange 30 of the separating pot 28 is adhesively bonded to the housing 10, more specifically to the contact shoulder 42. In this manner, the pump housing 16 is fixed in the housing 10 in the axial direction.

[0079] FIG. 15 shows an eighth embodiment of the liquid pump. 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.

[0080] The difference between the eighth embodiment and the preceding embodiments is that, in the eighth embodiment, the flange 30 of the separating pot 28 is sealingly connected to the housing 10 by means of a screw connection (see screw 61). A seal can thereby be interposed in the region of contact with the contact shoulder 42.

[0081] FIG. 16 shows a ninth embodiment of the liquid pump. 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.

[0082] The difference between the ninth embodiment and the preceding embodiments is that, in the ninth embodiment, the flange 30 of the separating pot 28 is riveted or staked to the housing 10. By way of example, a plastics rivet 62 is shown here, which rivet is deformed by heat staking such that the flange 30 of the pump housing 16 is applied to the inner side of the base 12 of the housing 10. Here too, a seal can be provided between the flange 30 and the contact shoulder 42 in order to ensure a fluid-tight connection.

[0083] FIG. 17 shows a tenth embodiment of the liquid pump. 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.

[0084] The difference between the tenth embodiment and the preceding embodiments is that, in the tenth embodiment, the separating pot 28 is not produced completely separately from the housing 10 and then connected thereto during mounting, but the side wall 32 of the separating pot is in the form of a pipe socket which is formed in one piece with the housing 10. The base 34 of the separating pot 28 is then seated on the end face of this pipe socket, wherein the base 34 is here in the form of a separating cover. It is sealingly connected, for example welded, to the end face of the pipe socket 32.

[0085] Before the separating cover 34 is welded to the pipe socket 32, the pump housing 16 with the components 18, 20 of the pump and the rotor 22 of the electric motor is inserted into the interior of the housing 10. In order to fix these components in the axial direction, the pump housing 16 is connected to the housing 10 in the vicinity of the base 12. For this purpose, a connection 70, indicated schematically, which acts axially and/or radially, can be used. For example, the pump housing 16 can be screwed to the housing 10. It is also possible to weld the pump housing 16 inside the housing 10.