WO2019215035A1

WO2019215035A1 - Electrical fluid pump and motor vehicle transmission

Info

Publication number: WO2019215035A1
Application number: PCT/EP2019/061382
Authority: WO
Inventors: Stephan Roos; Nico WIESSMANN
Original assignee: Brose Fahrzeugteile GmbH & Co. Kommanditgesellschaft, Würzburg
Priority date: 2018-05-08
Filing date: 2019-05-03
Publication date: 2019-11-14
Also published as: DE102018210415A1

Abstract

The invention relates to an electrical fluid pump (6) for a motor vehicle, in particular an oil pump for a motor vehicle transmission (2), having a pump unit (30) with a pump housing (32) and with a pump flange (34) which closes the pump housing (30), wherein the pump housing (32) and the pump flange (34), in the joined state, form a peripheral mounting drain (38), wherein the pump housing (32) and/or the pump flange (34) has, on its outer periphery, a catching region (48) for catching and collecting fluid (8), and wherein the catching region (48) opens into the mounting drain (38) which conveys the fluid (8) away on the peripheral side in the manner of a canal.

Description

description

Electric fluid pump and motor vehicle transmission

The invention relates to an electric fluid pump for a motor vehicle, in particular oil pump for a motor vehicle transmission, comprising a pump unit with a pump housing and with a pump housing concealing the pump housing flange, wherein the pump housing and the pump flange are joined to form a circumferentially extending mounting channel. The invention further relates to a motor vehicle transmission of a motor vehicle, with such a fluid pump.

An electric fluid pump serves to convey a fluid within a fluid circuit. An oil pump and in particular also a so-called auxiliary or additional pump serves here for conveying oil as a lubricant and as a transfer member in a hydraulic circuit for in particular moving parts or components, for example also of an internal combustion engine, hybrid-technically or electrically driven vehicle ( motor vehicle).

Such an oil pump usually generates an oil circuit due to their conveying properties, for example with an oil sump for receiving excess oil and / or leakage oil. An auxiliary or auxiliary pump driven, for example, electrically or by an electric motor often serves for at least temporary lubrication or additional lubrication of transmission parts of a vehicle transmission, in particular of an automatic transmission. The extracted oil often serves to cool components or additional components of the drive train of such a vehicle. Such oil pumps are to be designed for relatively large temperature ranges or designed to be constructive. The temperature range to be controlled or taken into account is frequently between, for example, -40 ° C. and, for example, 130 ° C. It should also be taken into account here that the lubricant (oil) used has a certain or specific viscosity which is temperature-dependent and thereby decreases with increasing temperature, that is to say is greater at lower temperatures, ie at higher temperatures.

Therefore, especially at higher operating temperatures or operationally increasing temperatures, the risk of leaks also increases. The reason for this is that, on the one hand, the avoidance of leakage causes a correspondingly tight pump housing, while on the other hand due to the high temperature fluctuations, housing expansions, ie different expansions of the pump housing and / or the relevant pump parts with increasing temperatures and thus decreasing viscosity of the oil used or

Lubricant increasingly tend to leaks, which at low temperatures and thus high viscosity of the oil or lubricant show less pronounced inclination. Such an oil pump usually comprises an electric motor driven pump unit. The pump unit typically has a pump rotor, which is accommodated in an approximately pot-like pump housing. The pump housing is in this case closed at the end, for example, by means of a pump cover or pump flange.

The pump housing and the pump flange are typically machined, in particular on the contact surfaces against which they abut one another in the assembled state. As a rule, there is no additional sealing element at the interface between the cup-shaped pump housing and the pump flange; instead, the pump housing and the pump flange are screwed together without seal, forming a mounting gap or a mounting groove. In addition to a high surface quality and a very good In particular, the contact pressure of the two housing parts relative to each other is a parameter which determines the tightness of the pump unit. In general, this contact pressure is effected by means of a screw connection, wherein in the case of a round pump housing usually four fastening screws are used in order to ensure a sufficiently high and uniform contact pressure. The fastening screws are typically arranged in a distribution measure (grid) distributed uniformly along the circumferential direction of the pump unit. In other words, the four fastening screws are typically rectangular, ie offset by 90 ° relative to one another.

In space-reduced applications, it is possible that an attachment of the pump flange on the pump housing by means of four mounting screws is not feasible. In such a space-reduced case, three fastening screws are preferably used, which are arranged in particular uniformly offset by 120 ° to each other on the pump flange. In such space-reduced applications, it is also possible that the three mounting screws can not be arranged in a 120 ° distributed distribution dimension, but only a 90 ° distribution measure is possible, so an approximately rectangular screw distribution is realized, in which a corner without screws is executed. Thus, only an uneven contact pressure is realized over the circumference of the pump unit. In particular, the contact pressure or the contact pressure in the screwless corner area is reduced.

If the pump unit is not completely inserted or sunk in an oil sump, it is possible that due to the reduced contact pressure, ambient air enters the pump housing via the mounting channel at the location of the screwless corner area. By such an air inlet on the one hand the Pump efficiency reduced. On the other hand, it is possible for an undesired air inlet that the oil pump is damaged or completely destroyed.

The invention has for its object to provide a particularly suitable electric fluid pump for a motor vehicle. In particular, an improved sealing concept for sealing the interface between the pump housing and the pump flange is to be specified, which prevents intrusion of ambient air into the pump housing outside of an oil or fluid sump. The invention is further based on the object of specifying a motor vehicle transmission with such a fluid pump.

With regard to the electric fluid pump, the object with the features of claim 1 and in terms of the motor vehicle transmission with the features of claim 7 is achieved according to the invention. Advantageous embodiments and continuing fertilization are the subject of the dependent claims. The advantages and preferred embodiments cited with regard to the fluid pump can also be applied to the motor vehicle transmission and vice versa.

The electric fluid pump according to the invention is suitable for a motor vehicle and set up. The fluid pump is in this case designed in particular as an oil pump for a motor vehicle transmission. The fluid pump has a pump unit with a pump housing and with a pump flange closing the pump housing. In the joining or assembly state, the pump housing and the pump flange form a circumferential mounting channel (mounting gap). The pump housing and the pump flange are in particular machined, and are each provided at the edge with a chamfer, wherein the mounting channel is formed in particular by the two mutually guided chamfers of the pump housing on the one hand and the pump flange on the other. The mounting channel thus has, for example, an approximately V-shaped cross-sectional shape. The pump housing and / or the pump flange has at its outer periphery a collecting area for collecting and collecting fluid. Here and in the following, the conjunction "and / or" is to be understood in such a way that the features linked by means of this conjunction can be formed both jointly and as alternatives to one another.

The trough-shaped catchment area, for example, opens into the mounting channel, as a result of which the fluid is channel-like on the circumference and can be discharged or is removed. This means that the collecting area in the region of the mounting channel has, for example, a drain opening.

In other words, the collected and collected fluid is routed along the sealless (housing) interface between the pump housing and the pump flange. If the interface has a leakage or leakage point, as can occur, in particular, in the case of an uneven contact pressure between the pump housing and the pump flange, then the guided fluid prevents the entry of ambient air into the pump unit. Instead of ambient air, therefore, only the fluid enters the pump unit, which, however, is conveyed anyway by means of the fluid pump. As a result, the pump unit is reliably and in a simple manner effectively sealed against the ingress of ambient air. Thus, a particularly suitable electric fluid pump is realized.

The collected and collected in the collecting area fluid is in particular a lubricating oil, preferably a return or dripping oil. The lubricating oil is used here, for example, for cooling the pump unit. The term (lubricating) oil is here in particular not restrictive to understand mineral oils, but also a fully synthetic or semi-synthetic oil, a silicone oil, or other oily liquids such as a hydraulic fluid or a coolant can be used. It is essential that the fluid delivered by the pump unit and the fluid collected and collected by the catchment area are the same. Furthermore, the fluid should have at least a certain viscosity, so that any point of leaks or leakage along the interface or mounting channel can be reliably wetted and covered.

In a suitable embodiment, the pump housing and the pump flange are joined to one another on a suction side of the pump unit. In other words, the interface or the mounting channel is arranged in the region of the suction side of the fluid pump. This ensures that the fluid is sucked into the pump unit in the area of leaks or leaks, thus preventing air from entering.

In an advantageous development, the collecting area is formed by ribs which project approximately radially upwards on the outer circumference of the pump housing. The ribs are in one piece, so one piece or monolithic, molded to the pump housing and / or the pump flange. As a result, the catchment area can be produced in a simple manner with little effort and at low cost. The pump housing and the pump flange are produced here in particular as die-cast parts, for example of an aluminum material.

In an expedient embodiment, the pump housing and the pump flange are joined by means of a number of fastening screws distributed around the circumference. This reliably ensures a reliable contact pressure between the housing parts.

In a preferred embodiment, the pump housing and the pump flange by means of three circumferentially, in particular by 90 °, arranged offset fastening screws joined together. The fastening screws thus have an approximately rectangular distribution dimension, wherein a screw-free point is formed in a corner region, along which the fluid guided by the mounting channel is guided or guided along. Due to the uneven arrangement The fastening screws causes a non-uniform contact pressure of the pump flange to the pump housing, so that in the corner region on the mounting channel a potential leakage point is formed. The guided along the mounting channel fluid prevents ambient air enters the interior of the pump unit. As a result, an air-tight pump unit of the fluid pump is always realized even in installation space-reduced installation situations.

Preferably, the pump unit is designed as a positive displacement pump (external gear pump), sickle cell pump or vane pump. In a particularly suitable embodiment, the pump unit is designed in particular as a gerotor pump (G rotor pump), and thus has a pump rotor designed as a gerotor. As a result, a relatively inexpensive and comparatively pulsation-free fluid delivery is possible. Such a pump rotor has a rotor set with an internally toothed outer ring (outer toothed ring) and an externally toothed inner rotor (inner toothed ring). In such a Innenzahnrand- or gerotor pump as a special type of gear pump runs in contrast to the external gear pump, the driving gear eccentric in the outer toothed ring. In this gerotor pump, the medium is conveyed by the volume-varying displacement space between the tooth spaces. In other words, in this gear pump, which is also referred to as a sickle pump, the medium to be delivered is conveyed in the spaces between the tooth gaps of the two toothed wheels, whereby the teeth pass through the sickle between the inwardly directed inner teeth of the outer toothed ring and the outwardly directed outer teeth of the inner toothed wheel be sealed. In a gerotor pump, the outer ring usually has exactly one more tooth than the inner wheel (trochoid toothing).

In a preferred application, the electric fluid pump described above is part of a motor vehicle transmission. The fluid pump is in this case designed, in particular, as an oil pump for conveying (lubricating) oil and, for example, arranged in the region of a transmission actuator, so that return flow or drip oil of the transmission actuator is collected and collected in the catchment area. As a result, a particularly expedient and durable vehicle transmission is formed. Hereinafter, an embodiment of the invention is explained in detail with reference to a drawing. Show:

1 is a schematic and simplified representation of a motor vehicle transmission with an electric fluid pump,

2 is a perspective view of the fluid pump with a pump unit and with an electric motor and with a functional unit,

3 is a perspective view of a detail of the electric motor and the pump unit,

Fig. 4, Fig. 5 in perspective view of the pump unit with a view of a

Front side,

Fig. 6 in plan view, the end face of the pump unit, and

7 shows a perspective view of the pump unit with a view of a catchment area.

Corresponding parts and sizes are always provided with the same reference numerals in all figures.

1 shows a schematic and simplified representation of a motor vehicle transmission 2 of a motor vehicle. The motor vehicle transmission has an oil circuit 4 with an electric or electromotive fluid pump 6 as a combined main oil pump and auxiliary or auxiliary pump for conveying a fluid 8, in particular a (lubricating) oil to transmission parts 10 of the motor vehicle transmission 2. The hereinafter also referred to as oil pump (Fluid) pump 6 has an electric motor 12 as an electric drive. During operation of the electric motor 12 and the pump 6, the oil 8 by means of a vacuum line 14 from an oil sump 16 sucked via a (pump) inlet 18 and pumped through a (pump) outlet 20 into an oil line 22, which is divided into a main oil line 24 and an auxiliary or auxiliary line 26. The main oil line 24 forms a main oil circuit of the oil circuit 4 and is provided in particular for the supply and actuation of hydraulic transmission actuators 28, with which, for example, the gears of the transmission part 10, which is preferably designed as an automatic transmission or dual-clutch transmission, inserted or switched. The auxiliary or additional line 26 is correspondingly in particular part of an auxiliary or additional circuit for at least temporary lubrication or additional lubrication of the gear arrangement, such as, for example, the gear part 10.

The oil pump 6 is shown in FIG. 2 comparatively detailed. The oil pump 6 comprises a pump unit 30 with a pump mechanism, not shown in greater detail, for conveying the oil 6, which is arranged in a pump housing 32.

The approximately pot-like pump housing 32 is closed at the end face with a frontal pump cover or pump flange 34. In this case, the pump housing 32 and the pump cover 34 are joined together in particular on the suction side of the pump unit 30.

The pump mechanism is drivingly coupled to the electric motor 12. For this purpose, the electric motor 12 is fastened to the pump housing 32 at the end opposite the pump flange 34.

The pump unit 30 is designed in this embodiment as a gerotor pump (G-rotor pump), and thus has a designed as a gerotor pump rotor as a pump mechanism. At the pump housing 32 opposite end face of the electric motor 12, a function carrier 36 is provided, which carries a (motor) electronics for operating the electric motor 12. FIG. 3 shows a detail of the pump unit 30 with a view of an upper side facing the transmission part 10 or the transmission actuators. The transition region or the mechanical interface between the pump housing 32 and the pump flange 34 is designed as an approximately channel-like mounting channel 38. The pump housing 32 and the pump flange 34 are in particular machined and in this case are each provided peripherally with a peripheral chamfer, the mounting channel 38 being formed in particular by the two chamfers of the pump housing 32 on the one hand and the pump flange 34 on the other hand. The mounting trough 38 thus extends along the circumferential direction of the pump unit 30. As can be seen in particular in FIGS. 4 to 6, the pump housing 32 and the pump flange 34 are joined by means of three fastening screws 40 arranged distributed over the circumference. The fastening screws 40 are in this case arranged in particular in an approximately rectangular distribution dimension, so that the three fastening screws are offset 90 ° to one another. Thus, a screwless point or corner region 41 is formed, which is preferably arranged in the region of a suction kidney 42 of the pump unit 30 indicated in dashed lines in FIG. 6.

As can be seen for example in FIG. 7, the pump housing 32 and the pump flange 34 are each designed with a rib or rib contour 44. The rib contours 44 are formed approximately radially upwardly on the outer circumference of the pump housing 32 or of the pump flange 34, and run essentially along the respective circumferential direction (tangential direction, azimuthal direction).

The pump housing 32 and the pump flange 34 furthermore have an integrally formed eyelet on the corner diametrically opposite the corner region 41. like receptacle 46 for the fastening screw 40, which are arranged in the mounting state axially aligned with each other.

The axially extending along the pump unit 30 receptacle 46 and the hie ran in one piece, so one-piece or monolithic, subsequent rib contours 44 form an approximately trough-shaped collecting area 48 for collecting and collecting the oil 8. The mounting channel 38 extends here through the collecting area 48, so that it effectively opens into the mounting channel 38. In the preferred application, the oil pump 6 is arranged below the transmission part 10 or a transmission actuator 28 or other gear arrangement of the motor vehicle transmission 2, as shown schematically in FIG. 1, so that dripping return or dripping oil 6 drips off in the direction of the catchment area 48 or is discharged. The oil 6 collects in the collecting area 48 and is discharged via the mounting channel 38 on the circumference of the pump unit 30 to the corner area 41.

In the corner region 41, the contact pressure due to the non-existent fastening screw 40 is reduced, whereby due to the oil 6 guided in the mounting channel 38, ambient air is prevented from being sucked into the pump unit.

The invention is not limited to the embodiment described above. Rather, other variants of the invention can be derived therefrom by the person skilled in the art without departing from the subject matter of the invention. In particular, all individual features described with the exemplary embodiment can also be combined with each other in other ways, without departing from the subject matter of the invention. LIST OF REFERENCE NUMBERS

2 motor vehicle transmission

4 oil circuit

6 fluid / oil pump

8 fluid / oil

10 gear part

12 electric motor

14 vacuum line

16 oil sump

18 inlet

20 outlet

22 oil line

24 main oil line

26 auxiliary / auxiliary oil line

28 gear actuator

30 pump unit

32 pump housings

34 pump cover / pump flange 36 function carriers

38 mounting channel

40 fixing screw

41 point / corner area

42 suckling kidneys

44 rib / rib contour

46 recording

48 catchment area

Claims

claims

1. An electric fluid pump (6) for a motor vehicle, in particular an oil pump for a motor vehicle transmission (2), comprising a pump unit (30) with a pump housing (32) and a pump flange (34) closing the pump housing (30),

- wherein the pump housing (32) and the pump flange (34) in the joining state form a circumferential mounting channel (38),

- Wherein the pump housing (32) and / or the pump flange (34) on its outer periphery a collecting area (48) for collecting and

Collecting fluid (8), and

- Wherein the collecting area (48) in the mounting channel (38) opens, which discharges the fluid (8) channel-like peripherally.

2. Electric fluid pump (6) according to claim 1,

characterized,

in that the pump housing (32) and the pump flange (34) on the suction side of the pump unit (30) are joined together.

3. Electric fluid pump (6) according to claim 1 or 2,

characterized,

in that the collecting area (48) is formed by ribs (44) which project approximately radially upwards on the outer circumference of the pump housing (32) and / or the pump flange (34).

4. Electric fluid pump (6) according to one of claims 1 to 3,

characterized,

in that the pump housing (32) and the pump flange (34) are joined by means of a number of fixing screws (40) arranged distributed over the circumference.

5. Electric fluid pump (6) according to one of claims 1 to 4,

characterized,

in that the pump housing (32) and the pump flange (34) are joined by means of three fastening screws (40) arranged offset on the circumference, in particular by 90 °, a screw-free point (41) being formed, from which the mounting channel (38) guided guided fluid (8) along or is feasible.

6. Electric fluid pump (6) according to one of claims 1 to 5,

characterized,

the pump unit (30) has a pump rotor designed as a gerotor.

7. Motor vehicle transmission (2) with a fluid pump (6) according to one of claims 1 to 6.