DE102020131360A1 - Fluid pump, in particular for a component of a drive train of a motor vehicle - Google Patents

Abstract

The invention relates to a fluid pump with an electric motor (22, 24), a pump set (16, 18, 20) which is driven by the electric motor (22, 24), and a housing (10) in which the electric motor (22, 24) and the pump set (16, 18, 20) are arranged, characterized in that the housing (10) is designed as a one-piece, injection-moulded pot with a base (12) and side walls (14), the pump set (16, 18 , 20) rests against the base (12) and the electric motor (22, 24) is arranged on the open side of the housing (10) facing away from the base (12).

Description

The invention relates to a fluid pump with an electric motor, a pump set that is driven by the electric motor, and a housing in which the electric motor and the pump set are arranged.

The fluid pump is intended to be used in a drive train of a motor vehicle. For example, the fluid pump can be used to provide a flow of cooling oil, with which various components in a transmission or a clutch can be cooled or also lubricated. Provision can also be made for the fluid pump to be used to provide a hydraulic oil flow which is converted into an actuating force and an actuating stroke in an actuator. For example, a clutch can be switched with the hydraulic oil flow provided. The pump can also be used to pump other fluids, such as coolant for battery cooling, gear oil, lubricating oil, cooling oil, motor oil, transformer oil, insulating oil, etc.

Such fluid pumps are known in various embodiments. They can be designed as separate units, which are then connected to the component to be supplied via lines, or they can also be attached directly to another component, for example a transmission housing.

In a typical construction of such a fluid pump, the housing is designed in several parts, one housing part for the pump set and one housing part for the electric motor being used in most cases.

The disadvantage of the known designs is that the forces occurring during operation of the pump cannot be optimally absorbed and that there are long chains of tolerance.

The object of the invention is to create a fluid pump in which the forces that occur are optimally absorbed and which is characterized by short tolerance chains.

To solve this problem, a fluid pump of the type mentioned at the outset provides for the housing to be in the form of a one-piece, injection-molded pot with a base and side walls, with the pump assembly resting on the base and the electric motor being arranged on the open side of the housing facing away from the base is. The invention is based on the idea of completely eliminating any step of assembling different housing parts to one another by using a single piece injection molded housing which houses the components of the fluid pump. On the one hand, this results in very simple assembly with short tolerance chains, since all the components are assembled from one side of the housing and are in contact with the corresponding configurations of the housing. As a result, no tolerances have to be taken into account that can occur when assembling different housing parts together. On the other hand, the forces occurring during operation of the fluid pump are evenly absorbed and passed on within the housing.

A suction opening and/or a pressure opening of the fluid pump are preferably arranged in the bottom of the housing. In the simplest case, the openings can be in the form of passages through the base of the housing, so that there is a direct connection to another component when the fluid pump is mounted with its base against the other component. Type-specific connection interfaces can be implemented with little effort by arranging the suction opening and the pressure opening differently in the base, but otherwise the housing is standardized.

The opening in the bottom of the housing is preferably associated with a sealing configuration, in particular a sealing groove or a cylinder surface. A sealing ring can be accommodated in the sealing groove in order to achieve an axial seal, ie a seal in which the contact pressure forces that occur are applied in the axial direction. A cylindrical surface can also be used, into which a socket of another component engages, or which itself represents the outer surface of a socket, with a seal lying against the cylindrical surface, in which case the sealing forces are then applied in the radial direction.

According to one embodiment of the invention, it is provided that the pump set has a pump housing that rests against the floor. The inner surface of the bottom serves as a reference plane during assembly of the fluid pump, and an axial play of a pump rotor within the pump housing is determined solely on the basis of the dimensions of the pump housing and the rotor; the housing has no influence.

The pump housing is preferably centered in the housing of the fluid pump, so that no tolerance chains occur in the radial direction either.

According to one embodiment, the pump housing is firmly connected to the housing, in particular welded or screwed. In this way, during operation of the fluid pump occurring axial forces are diverted directly into the housing.

According to a preferred embodiment of the invention, a separating pot is provided, which extends between a stator and a rotor of the electric motor and separates a hydraulic oil side of the fluid pump from an electronics side. The separating pot ensures that no hydraulic oil can escape from the fluid pump to the electronics side.

According to a preferred embodiment of the invention, it is provided that the separating bowl has a flange which is connected to the housing. The separating pot is therefore designed as a component that is separate from the housing, as a result of which it can be designed with a particularly small wall thickness. The separating pot can in particular be designed as a thin-walled injection molded part made of plastic.

It is particularly advantageous if the wall thickness is in the range from 0.2 to 0.4 mm, in particular in the order of 0.3 mm. This is advantageous with regard to high efficiency, since the wall thickness of the separating pot increases the air gap between the stator and the rotor. The smaller the wall thickness of the separating pot, the smaller the air gap can be.

The flange is firmly connected to the housing, in particular welded, glued, screwed or riveted, so that a reliable seal is guaranteed. Furthermore, the forces occurring during operation are absorbed immediately.

The flange rests against the pump housing so that it also serves to press the pump housing against the ground.

According to an alternative embodiment of the housing, the separating pot is formed by a tubular extension that is designed in one piece with the housing and a separating cover that is tightly connected to the end face of the tubular extension. This design can also be injection molded very well with very high precision and a low wall thickness in the area of the tube attachment.

A printed circuit board is arranged on the open side of the housing facing away from the floor and is encapsulated in the housing together with the stator. The casting compound supports the separating pot from the outside so that the hydraulic forces that occur during operation can be well absorbed. In addition, the casting compound has good heat-conducting properties, so that the heat loss that occurs is dissipated well.

Screw-on openings can be integrated into the bottom of the housing in order to mount the fluid pump on another component and to directly generate the contact pressure forces in the area of the bottom of the housing that are desired with regard to reliable sealing.

Depending on the respective spatial conditions, the screw-on openings can also be provided at a different location on the housing, for example spaced apart from the floor by half the housing in the axial direction or also on the open side of the housing.

The pump set of the fluid pump can be designed appropriately depending on the respective requirements (in particular desired delivery pressure and desired delivery volume). Gerotor pumps, in particular gerotor pumps, are particularly suitable for fluid pumps for actuating clutches in the drive train of motor vehicles.

The pressure provided by the fluid pump can be on the order of 0.8 bar for supplying lubricant up to 45 bar for actuating a clutch.

• - 1 eine Draufsicht auf eine Fluidpumpe gemäß einer ersten Ausführungsform der Erfindung;
• - 2 einen Schnitt entlang der Ebene II-II von 1;
• - 3 in vergrößertem Maßstab das Detail III von 2;
• - 4 eine perspektivische Unteransicht der Fluidpumpe von 1;
• - 5 eine Unteransicht der Fluidpumpe von 1;
• - 6 eine Schnittansicht entlang der Ebene VI-VI von 5;
• - 7 in vergrößertem Maßstab das Detail VII von 6;
• - 8 eine perspektivische Draufsicht auf die Fluidpumpe von 1;
• - 9 eine perspektivische Unteransicht einer zweiten Ausführungsform der Erfindung;
• - 10 einen Querschnitt durch eine Fluidpumpe gemäß einer dritten Ausführungsform;
• - 11 einen Querschnitt durch eine Fluidpumpe gemäß einer vierten Ausführungsform;
• - 12 einen Querschnitt durch eine Fluidpumpe gemäß einer fünften Ausführungsform;
• - 13 einen Querschnitt durch eine Fluidpumpe gemäß einer sechsten Ausführungsform;
• - 14 einen Teil eines Querschnitts durch eine Fluidpumpe gemäß einer siebten Ausführungsform;
• - 15 einen Teil eines Querschnitts durch eine Fluidpumpe gemäß einer achten Ausführungsform;
• - 16 einen Teil eines Querschnitts durch eine Fluidpumpe gemäß einer neunten Ausführungsform; und
• - 17 einen Teil eines Querschnitts durch eine Fluidpumpe gemäß einer zehnten Ausführungsform.

The invention is described below with reference to various embodiments which are illustrated in the accompanying drawings. In these show:

• - 1 a plan view of a fluid pump according to a first embodiment of the invention;
• - 2 a section along the plane II-II of 1 ;
• - 3 on an enlarged scale the detail III of 2 ;
• - 4 a bottom perspective view of the fluid pump of FIG 1 ;
• - 5 a bottom view of the fluid pump of 1 ;
• - 6 a sectional view along the plane VI-VI of FIG 5 ;
• - 7 on an enlarged scale the detail VII of 6 ;
• - 8th a top perspective view of the fluid pump of FIG 1 ;
• - 9 a bottom perspective view of a second embodiment of the invention;
• - 10 a cross section through a fluid pump according to a third embodiment;
• - 11 a cross section through a fluid pump according to a fourth embodiment;
• - 12 a cross section through a fluid pump according to a fifth embodiment;
• - 13 a cross section through a fluid pump according to a sixth embodiment;
• - 14 a part of a cross section through a fluid pump according to a seventh embodiment;
• - 15 a part of a cross section through a fluid pump according to an eighth embodiment;
• - 16 a part of a cross section through a fluid pump according to a ninth embodiment; and
• - 17 a part of a cross section through a fluid pump according to a tenth embodiment.

In the 1 until 8th a first embodiment of the fluid pump is shown. It serves to provide a hydraulic oil flow for a drive train of a motor vehicle. This can be used to lubricate or cool drivetrain components. The hydraulic oil flow can also be intended to be converted into an actuating stroke in actuators, for example in order to shift a clutch.

The fluid pump has a housing 10 which is made in one piece and is pot-shaped, ie has a bottom 12 and a plurality of side walls 14 . The housing 10 is an injection molded component made of plastic.

If higher strengths are required, the housing 10 can also be made of other materials. An example is an aluminum alloy housing that is machined at least in part.

A pump set and an electric motor are arranged in the housing 10 .

The pump assembly includes a pump housing 16 and a pump rotor 18 housed therein. Furthermore, in the embodiment of the fluid pump shown here, there is an outer ring 20 which is rotatably accommodated in the pump housing 16 .

The fluid pump is a pump of the gerotor pump type. In principle, other pump types are also possible.

The electric motor has a rotor 22 and a stator 24 . The stator 24 is arranged in a stationary manner in the housing 14 and the rotor 22 is non-rotatably connected to a shaft 26 which is rotatably supported 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 located within the pump housing 16 .

The pump housing 16 is dimensioned in such a way that the pump rotor 18 can be accommodated in it with the necessary axial play.

The pump housing 16 is centered in the interior of the housing 10 by means of radially protruding centering lugs 17 (see in particular 3 ), which rest against the inner wall of the housing 10. In order to avoid accumulations of material there, which can cause shrinkage problems during injection molding, the centering lugs are hollow. In this way, a certain spring effect in the radial direction is also ensured, which supports centering.

A separating pot 28 is provided, 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 with a circular-cylindrical cross section, and an end wall 34 .

The separating pot 28 is an injection molded part made of plastic, which has a wall thickness of the order of 0.3 mm, at least in the area of the side wall 32 which extends between the rotor 22 and the stator 24 .

In particular, thermoplastics and/or duroplastics can be used for the housing 10, the pump housing 16 and the separating pot 28. PPA or PPS are particularly suitable as materials.

The pump set and the electric motor are assembled from the open side of the housing 10 into the interior thereof. The pump housing 16 rests on the inside of the bottom 12 and the flange 30 of the separating cup 28 presses on a peripheral contact collar 36 which is designed in one piece with the pump housing 16 . The flange 30 itself is welded to the housing 10 with an axially projecting weld collar 38 (see in particular 3 ).

In order to press the pump housing 16 against the bottom 12 of the housing 10 in the axial direction, 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 bowl 28 is welded to the weld collar 38 of the housing 10 welded. An ultrasonic welding method can be used for this, for example.

In 3 It can be seen that the flange 30 has a groove 40 in which the weld collar 38 is positioned. The dimensions of the components are dimensioned relative to each other in the axial direction such that the flange 30 presses the pump housing 16 against the bottom 12 of the housing 10 via the contact collar 36 and is reliably welded to the welded collar 38 before the contact collar 36 is attached to the in 3 visible contact shoulder 42 of the housing 10 is present.

When assembling the fluid 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 . Then the flange 30 of the separating pot 28 is pressed against the weld collar 38 and welded there. During this process, the weld collar 38 is compressed in the axial direction until the pump housing 16 is pressed firmly against the bottom 12 of the housing 10 with its end face via the contact collar 36 which rests on the flange 30 of the separating pot 28 . The resulting welding flash can be accommodated in the groove 40 of the flange 30 without any problems.

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

When welding the flange 30 to the welding collar 38, any suitable welding method can be used in principle, with which two weldable plastics are connected to one another. Examples are a laser welding method, an ultrasonic welding method, and a friction welding method.

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

In 2 an insertion channel 46 for an electrical connection plug is also shown, with which the fluid pump is electrically contacted.

After the printed circuit board has been mounted, the area of the housing in which the stator 24 and the printed circuit board 44 are arranged is filled with a casting compound. On the one hand, this serves as a mechanical support for the separating pot 28 and, on the other hand, as a material for dissipating heat loss from the stator 24.

Also arranged in the bottom 12 of the housing 10 are a suction opening 48 and a delivery opening 50 which open into the interior of the housing 10 in the area in which the pump unit is located. As for example in 6 As can be seen, suction port 48 and discharge port 50 extend axially through bottom 12 of housing 10 .

In the embodiment of 1 until 8th a sealing ring 52 is assigned to each opening and is arranged in a sealing groove 54 .

A plurality of screw-on openings 56 are integrally integrated into the housing for attachment of the fluid pump. In the exemplary embodiment shown, these are integrated into the base 12 so that the fluid pump can be screwed directly to a transmission housing, for example. The seals 52 provide a seal on the transmission housing in the axial direction, and the fluid pump sucks in directly from the transmission housing, without a separate reservoir and corresponding lines being required.

In this way, with a minimum number of seals, namely exactly two seals, reliable sealing and a high degree of security against an undesired escape of hydraulic oil are ensured.

In 9 a second embodiment of the invention is shown. The same reference numerals are used for the components known from the first embodiment, and reference is made to the above explanations.

The difference between the second and the first embodiment is that the second embodiment does not use two separate seals 52 but a single seal 52 which has a separating web 53 which separates the suction opening 48 from the pressure opening 50 .

In 10 a third embodiment of the fluid pump is shown. The same reference numerals are used for the components known from the first two embodiments, and reference is made to the above explanations.

The difference between the third and the previous embodiments is that in the third embodiment an axially acting seal is provided for the suction opening 48, which is arranged in a sealing groove 54, while a cylindrical sealing surface 58 is provided for the pressure opening 50, so that a radial seal is formed.

In 11 a fourth embodiment of the fluid pump is shown. The same reference numerals are used for the components known from the previous embodiments, and reference is made to the above explanations in this respect.

The difference between the fourth and third embodiments is that the fourth embodiment does not use an axial seal for the suction port 48, but a radial seal. For this purpose, a stepped, cylindrical outer surface 59 is formed on a connecting piece 60 which is designed in one piece with the base 12 .

In 12 a fifth embodiment of the fluid pump is shown. The same reference numerals are used for the components known from the previous embodiments, and reference is made to the above explanations in this respect.

The difference between the first and the fifth embodiment is that in the fifth embodiment the screw-on openings 56 are not arranged on the level of the base 12 but are set back somewhat in the axial direction towards the open side of the housing 10 . In the exemplary embodiment shown, the screw-on openings 56 are located approximately halfway up the housing 10.

In 13 a sixth embodiment of the fluid pump is shown. The same reference numerals are used for the components known from the previous embodiments, and reference is made to the above explanations in this respect.

The sixth embodiment differs from the fifth and the first embodiment in that the screw-on openings 56 are now arranged at the level of the open end of the housing 10 . The sealing in the area of the suction opening 48 and the pressure opening 50 continues to take place in the axial direction, in that the housing 10 is pressed in the axial direction from the plane of the screw-on openings 56 in the direction of the base 12 against a counter surface. The housing 10 can be used in the manner of a cartridge in, for example, a suitably designed receiving recess and screwed tight there.

In 14 a seventh embodiment of the fluid pump is shown. The same reference numerals are used for the components known from the previous embodiments, and reference is made to the above explanations in this respect.

The difference between the seventh embodiment and the previous embodiments is that in the seventh embodiment the flange 30 of the separating cup 28 is glued to the housing 10, more precisely to the contact shoulder 42. In this way the pump housing 16 is in the housing in the axial direction 10 attached.

In 15 an eighth embodiment of the fluid pump is shown. The same reference numerals are used for the components known from the previous embodiments, and reference is made to the above explanations in this respect.

The difference between the eighth embodiment and the previous embodiments is that in the eighth embodiment the flange 30 of the separating cup 28 is tightly connected to the housing 10 by means of a screw connection (see screw 61). In the area of contact with the contact shoulder 42, a seal can be placed underneath.

In 16 a ninth embodiment of the fluid pump is shown. The same reference numerals are used for the components known from the previous embodiments, and reference is made to the above explanations in this respect.

The difference between the ninth embodiment and the previous embodiments is that, in the ninth embodiment, the flange 30 of the separator bowl 28 is riveted or caulked to the housing 10 . A plastic rivet 62 is shown here as an example, which is deformed by hot caulking in such a way that the flange 30 presses the pump housing 16 against the inside of the bottom 12 of the housing 10 . A seal can also be provided here between the flange 30 and the contact shoulder 42 in order to ensure a fluid-tight connection.

In 17 a tenth embodiment of the fluid pump is shown. The same reference numerals are used for the components known from the previous embodiments, and reference is made to the above explanations in this respect.

The difference between the tenth embodiment and the previous embodiments is that, in the tenth embodiment, the separator bowl 28 is not made completely separate from the housing 10 and then connected to it during assembly, but rather the side wall 32 of the separator bowl is integral with the housing 10 engineered pipe approach is formed. The base 34 of the separating pot 28 is then placed on the end face of this pipe extension, with the base 34 being designed here as a separating cover. He is tightly connected to the end face of the pipe extension 32, for example welded.

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 bottom 12 . For this purpose, a schematically indicated connection 70 can be used, which acts axially and/or radially. 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.

Claims (15)

Fluid pump with an electric motor (22, 24), a pump set (16, 18, 20) of the electric motor (22, 24) is driven, and a housing (10) in which the electric motor (22, 24) and the Pump set (16, 18, 20) are arranged, characterized in that the housing (10) is designed as a one-piece, injection-moulded pot with a bottom (12) and side walls (14), the pump set (16, 18, 20) being Bottom (12) and the electric motor (22, 24) facing away from the bottom (12), open side of the housing (10) is arranged. fluid pump after claim 1 , characterized in that a suction opening (48) and / or a pressure opening (50) of the fluid pump in the bottom (12) of the housing (10) is arranged. fluid pump after claim 1 or claim 2 , characterized in that the opening (48, 50) in the bottom (12) of the housing (10) is associated with a sealing design (52; 58, 59), in particular a sealing groove or a cylinder surface. Fluid pump according to one of the preceding claims, characterized in that the pump set has a pump housing (16) which bears against the floor (12). fluid pump after claim 4 , characterized in that the pump housing (16) is centered in the housing (10). fluid pump after claim 4 or claim 5 , characterized in that the pump housing (16) is firmly connected to the housing (10), in particular welded or screwed. Fluid pump according to one of the preceding claims, characterized in that a separating pot (28) is provided which extends between a stator (24) and a rotor (22) of the electric motor and separates a hydraulic oil side of the fluid pump from an electronics side. fluid pump after claim 7 , characterized in that the separating pot (28) has a flange (30) which is connected to the housing (10). fluid pump after claim 8 , characterized in that the flange (30) is firmly connected to the housing (10), in particular welded, glued, screwed or riveted. fluid pump after claim 8 or claim 9 , characterized in that the flange (30) rests against the pump housing (16) and is preferably centered in the pump housing (16). fluid pump after claim 7 , characterized in that the separating bowl (28) is formed by a tubular extension (32) made in one piece with the housing (10) and a separating cover (34) tightly connected to the end face of the tubular extension (32). Fluid pump according to one of the preceding claims, characterized in that a printed circuit board (44) is arranged on the open side of the housing (10) facing away from the base (12) and is cast together with the stator (24) in the housing (10). . Fluid pump according to one of the preceding claims, characterized in that screw-on openings (56) are integrated into the base (12) of the housing (10). Fluid pump according to one of Claims 1 until 13 , characterized in that from the bottom (12) spaced apart in the axial direction screwing openings (56) are provided. Fluid pump according to one of the preceding claims, characterized in that the pump set (16, 18, 20) is a ring gear pump, in particular a gerotor pump.

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