Electric pumping device for a motor vehicle

Abstract

The invention relates to a pumping device for a motor vehicle, comprising a pump rotor 41 which conveys fluid from an inlet to an outlet, an electric drive device 6 for driving the pump rotor 41, wherein the drive device 6 comprises a drive stator 61 and a drive rotor 62, wherein the pump rotor 41 and the drive rotor 62 are each fixedly connected to a common drive shaft 7 which is rotatable between the pump rotor 41 and the drive rotor about a rotational axis D.The pump device also comprises a housing structure with a first housing part 1 and a second housing part 2, which divides the pump device into a pump section 101 and a motor section 102, wherein the first housing part 1 closes off the pump section 101, forms an axial end of the housing structure on one side and has a recess 11 on its opposite side through which a pump chamber 8 is provided within the pump section 101. The pump rotor 41 is rotatably arranged in the pump chamber 8.The second housing part 2 is axially inserted into the first housing part 1 by forming a press fit with the first housing part 1 and rests axially against the first housing part 1 along a contact plane E at the end of the pump chamber 8, wherein the first housing part 1 has an annular first fixing projection 12 at a radial end and the second housing part has an annular second fixing projection 21 at a radial end, which extends axially away from the contact plane E, wherein the second fixing projection 21 is pressed radially against the first fixing projection 12 to form the press fit.

Description

[0001] The invention relates to an electric pump device for a motor vehicle and to a motor vehicle with a pump device. The pump device can, in principle, be used as a coolant pump, oil pump, or the like, for example, in a coolant circuit and / or a lubricant circuit of a motor vehicle. The pump device is preferably designed as a positive displacement pump, in particular as a gerotor pump.

[0002] Unlike mechanical pumps, these types of pumps are driven by an electric drive unit, which is typically integrated into the pump. Such pumps are usually divided into a pumping section and a motor section. The electric drive unit is located in the motor section, while the pumping section contains one or more pump rotors for pumping fluid, such as lubricants like oil or similar substances, or coolants like glycol or similar substances. The fluid in question is a hydraulic fluid, i.e., not a gaseous fluid.

[0003] Electric pump devices are preferably used for the lubrication or cooling of components of an electrically powered vehicle, i.e., a vehicle powered exclusively or at least partially by an electric motor, thus an electric vehicle or a hybrid vehicle.

[0004] The integration of the electric drive unit into the pump device, particularly from previously mechanical pump devices, has led to comparatively complex pump designs, especially since the pump section and, in particular, part of the motor section are intended to be fluid-carrying, while components located in the motor section, such as electrical and / or electronic components, must be protected from the fluid, yet these components form at least part of the drive unit. Furthermore, a compact design for the pump device is desired.

[0005] In some known embodiments, for example, a drive rotor of the drive unit, which is connected to a pump rotor by means of a drive shaft, is immersed in fluid that is pumped in the pump area during normal operation of the pump. This is intended, for example, to enable cooling of the drive unit or electronic components, whereby good cooling can be achieved particularly if a reliable fluid flow can be provided along a defined flow path.

[0006] The components of the pump device are typically arranged in a multi-part, particularly stacked, housing structure. The design of this structure sometimes requires complex measures to ensure sufficient assembly and centering of the pump device components during manufacturing, while maintaining a compact form. One approach is to enclose a pump chamber in the pump area, in which the pump rotor is located, with as few housing parts as possible, for example, with just two. For instance, DE102021130216A1 discloses an electric pump device of the aforementioned type, in which improved centering of the individual components, particularly the drive stator, is achieved by means of an axially elongated housing part.Other known pump devices often feature a housing structure consisting of several axially arranged housing parts to provide adapted structures for the different areas of the pump device. It is desirable to make the design of the pump device, especially the housing structure, less complex and, in particular, to simultaneously reduce the number of interfaces between components that must be fluid-tight.

[0007] One object of the invention is to simplify the construction of pump devices of the type mentioned. In particular, one object of the invention is to provide a simply constructed pump device in which the fluid flow to and / or within the motor area is improved.

[0008] The problem is solved by a pump device with features of claim 1. The pump device according to the invention for a motor vehicle, in particular an electric vehicle and / or a hybrid vehicle, comprises at least one pump rotor configured to pump fluid, in particular a lubricant and / or a coolant, from an inlet of the pump device to an outlet of the pump device. During operation, fluid can be passed through the inlet and outlet via fluid lines that can be connected thereto, for example, coolant lines or lubricant lines. The pump device is configured to draw in fluid through the inlet and discharge it through the outlet during operation. Preferably, the inlet and / or the outlet is configured as a nozzle, with at least one of the nozzles preferably forming an end, in particular an axial end, of the pump device. Such an arrangement of inlet and / or outlet is particularly advantageous.The outlet allows for a radially compact design. The pump device according to the invention further comprises an electric drive unit for driving the pump rotor, wherein the drive unit comprises a drive stator, which preferably has at least three phase windings, and a drive rotor, in particular one made of permanent magnets.

[0009] The pump rotor and the drive rotor are each fixedly connected to the common drive shaft. This drive shaft of the pump device is preferably, at least in a section from the pump rotor to the drive rotor, and in particular entirely, made of a single piece, especially metal. The drive rotor and the pump rotor are arranged axially spaced apart on the drive shaft, in particular at opposite ends of the drive shaft, such that the distance to the respective end is less than 30%, and in particular less than 20%, of the axial extent of the drive shaft. The drive shaft is rotatably mounted between the pump rotor and the drive rotor about an axially extending axis of rotation. "Axial" and "radial" are to be understood with respect to this axis of rotation, with an axial direction extending in the direction of the axis of rotation and a radial direction extending perpendicular to it, in particular away from the axis of rotation.In principle, it is conceivable and encompassed by the invention to design the drive shaft as a hollow shaft. This would, for example, save weight. However, it is preferred that the drive shaft be designed as a solid shaft. This would, for example, prevent the drive shaft from deforming adversely when the pump rotor and the drive rotor are arranged on the drive shaft.

[0010] The pump device comprises a housing structure, which includes a first housing part, preferably a single piece, and a second housing part, preferably a single piece. The first housing part is preferably cup-shaped, particularly bell-shaped. The housing structure divides the pump device into a pump section, a motor section, and, in particular, an electronics section. The second housing part further divides the pump device into the pump section and the motor section. The motor section and pump section are arranged one behind the other, preferably without overlap, in the axial direction, with the motor section being located between the pump section and the electronics section. The pump rotor is located in the pump section, and the drive rotor is located in the motor section, such that the drive shaft extends proportionally into the motor section and the pump section, respectively.The first housing part encloses the pump area and, in an overlap area where the first housing part axially overlaps the second housing part, forms a radial outer surface of the pump device. Preferably, the first housing part encloses the pump area such that it forms both an axial outer surface and the radial outer surface of the pump device. On one side, the first housing part forms an axial end of the housing structure. Thus, the first housing part also forms, in particular, an end of the pump device. On its side opposite the axial end of the housing structure, the first housing part has a recess. This recess provides a pump chamber within the pump area.Preferably, the first housing part has a pump chamber side wall provided by the recess, which in particular extends continuously around the circumference of the drive shaft and points radially towards the axis of rotation. Preferably, the inlet and / or outlet are arranged on a side of the pump area, in particular the pump chamber, facing away from the motor area. The at least one pump rotor is rotatably arranged in the pump chamber. In preferred embodiments, the pump device can include at least one further pump rotor in addition to the pump rotor, wherein the pump rotors mesh together effectively for fluid transfer, in particular according to the principle of a positive displacement pump. The further pump rotor is preferably rotatably arranged in the pump chamber at a distance from the drive shaft.

[0011] The second housing part is axially inserted into the first housing part by means of a press fit and rests against the first housing part along a contact plane to close off the pump chamber. The pump chamber is thus sealed off from the outside and limited from the motor area by the corresponding contact between the first and second housing parts. The contact plane is to be understood as the imaginary plane along which the first and second housing parts are in physical contact. The contact plane is preferably located on the side of the pump rotor facing axially towards the drive rotor. In particular, the contact plane is located at the level of a rotor end face of the pump rotor facing the second housing part.Preferably, the first housing part extends axially, particularly from its axial end, and in particular at least 95% of the axial extent of the pump rotor, and in particular beyond the extent of the pump rotor, until it abuts the second housing part along the contact plane. This places the sealing point in a position favorable for sealing. Furthermore, a pump chamber side wall, adapted to the dimensions, in particular the axial dimensions, of the pump rotor, can be formed exclusively by the first housing part.

[0012] Thus, the second housing part preferably provides an end-face pump chamber wall. In particular, the second housing part includes a bearing, preferably designed as a plain bearing, for the rotatable mounting of the drive shaft. Preferably, the drive shaft is guided through a passage in the second housing part, the passage providing the bearing for the drive shaft. This allows the drive shaft to be rotatably mounted about its axis of rotation in the passage, at least relative to the second housing part. The end-face pump chamber wall extends radially around the bearing. In principle, embodiments are conceivable in which the drive shaft is radially mounted exclusively on the second housing part. However, it is generally preferred that the drive shaft be rotatably mounted on both the first and second housing parts, which allows for better positioning.

[0013] According to the invention, the first housing part has an annular first fixing projection at its radial end. Preferably, the first fixing projection is arranged radially adjacent to the second housing part, overlapping it axially like an apron. The second housing part has an annular second fixing projection at its radial end. The first housing part and the second housing part each preferably form their respective fixing projections integrally. In particular, the first fixing projection forms a radial end of the first housing part. In particular, the second fixing projection forms a radial end of the second housing part. The respective fixing projection extends axially away from adjacent areas of the respective housing part.According to the invention, the second fixing projection extends axially away from the contact plane, wherein, to form the press fit, the second fixing projection is pressed radially against the first fixing projection. Preferably, the press fit is designed as an interference fit between the first and the second fixing projection. Preferably, the first housing part has a first pressing surface that points radially inwards, i.e., towards the axis of rotation, and the second housing part has a pressing surface that points radially outwards, wherein the pressing surfaces bear against each other to form the press fit.In a preferred embodiment, the pressure surfaces are spaced apart from the contact plane and formed on the respective fixing projection, in particular such that a ring segment of the respective fixing projection extends to the respective pressure surface, and the respective pressure surface runs between the axial end of the respective fixing projection and the respective ring segment. Preferably, the pressure surface extends axially over at least 80%, and in particular over at least 95%, of the respective fixing projection, and in particular beyond the axial extent of the respective fixing projection. The respective pressure surface extends in particular along the circumference of the fixing projection, and in particular over at least 80% of the circumference, and in particular without interruption. According to one embodiment, the respective pressure surface extends axially beyond the respective fixing projection to both sides of the contact plane.This further improves the fit and stability of the housing parts. The second housing part is preferably arranged on the pump rotor, in particular such that, with the exception of the second fixing projection, the second housing part is arranged axially next to the pump rotor without overlap.

[0014] The invention provides a simple and compact pump device. Due to the inventive design of the housing structure, in which the first housing part essentially provides the pump chamber and the second housing part essentially acts as a cover on the first housing part, the radial installation space of the pump device is reduced, for example, because radially external connecting means for fixing the second housing part to the first housing part can be dispensed with. Furthermore, assembly during manufacturing of the pump device is simplified, since the pump rotor can be inserted into the recess provided by the first housing part and the pump chamber can be closed off by the pump chamber wall provided by the second housing part. No further housing parts are required to provide the pump chamber. Thus, additional sealing of contact surfaces is also unnecessary.The required geometry is already provided by the suitable design of the first and second housing parts, whereby the first and / or second housing part can generally preferably be manufactured as a casting, in particular a die-cast part, and / or as a sintered part. Preferably, the housing part manufactured as a die-cast part is made of aluminum. According to a particularly preferred embodiment, the first housing part is manufactured as a die-cast part, while the second housing part is manufactured as a sintered part. This advantageously aligns the respective manufacturing process with the complexity of the housing part.

[0015] According to a preferred embodiment, the first housing part has a fixing groove, particularly an integral one, extending axially to the second housing part and in particular being annular. In preferred embodiments, the annular fixing groove is open radially towards the pump chamber along at least one uninterrupted section. This allows fluid to be guided in a particularly space-saving manner between the inlet and the pump chamber and / or between the outlet and the pump chamber. In particular, the fixing groove is radially bounded by the first fixing projection, which in particular forms a first groove wall of the fixing groove that extends radially outwards towards the axis of rotation. In particular, the contact surface of the first housing part is formed by the groove wall. The fixing groove is arranged at least radially between the first fixing projection of the first housing part and the pump chamber.The second fixing projection is arranged, particularly to at least 80%, and in particular completely, within the fixing groove. The second fixing projection can extend to the bottom of the fixing groove. However, it is particularly preferred that the fixing projection is axially spaced from the bottom of the groove, particularly by at least 10%, and in particular by at least one axial groove depth. This ensures reliable contact between the second housing part and the first housing part along the contact plane and, in particular, simplifies the provision of a precisely machined pressing surface for the first housing part. In particular, the second fixing projection and the fixing groove are configured to correspond such that the side of the second fixing projection facing radially away from the first pressing surface is spaced from a second groove wall facing radially inner and away from the axis of rotation.For further improved sealing, in advantageous embodiments a sealant and / or a sealing element, particularly an elastomeric one, can be introduced into the fixing groove and, in particular, be in contact with both the first and second housing parts. The second fixing projection preferably extends axially away from the motor area, starting from the contact plane. It is generally advantageous for the second fixing projection to be arranged, particularly entirely, on the side of the second housing part facing away from the motor area.

[0016] The placement of the fixing projection on the pump side allows for a more axially compact design of the pump assembly, as the areas required for forming the press fit do not protrude into the motor area. This creates additional installation space for motor components without increasing the overall installation space of the pump assembly, since the second fixing projection can be located in a wall section of the first housing part due to the fixing groove.

[0017] Even if the press connection is to be provided over a larger axial extent to improve the fastening of the housing parts to each other and / or to improve the sealing effect, the motor area is not affected by this.

[0018] The pump device is generally and particularly preferably designed as an electric gerotor pump, which can bring about further improvements in terms of robustness and compactness. According to such a preferred embodiment, the pump rotor is designed as the inner rotor of a gerotor. The inner rotor has external teeth. In this embodiment, the pump device comprises a further pump rotor, which is arranged in the pump chamber. The further pump rotor is designed as an outer rotor and has internal teeth corresponding to the external teeth. The outer and inner rotors are arranged eccentrically to each other. The external and internal teeth mesh with each other, forming pumping zones whose respective volumes are variable for pumping fluid between the inlet and outlet.In particular, the outer rotor is radially mounted, especially exclusively, on the first housing part, particularly by contacting an outer surface of the outer rotor, extending radially away from the axis of rotation, against the first housing part, especially against the side wall of the pump chamber. Advantageously, the outer rotor and inner rotor are each rotatable about different axes of rotation, each relative at least to the second housing part. Preferably, the outer rotor is rotatable about a first axis of rotation, and the inner rotor is rotatable about a second axis of rotation spaced apart from the first axis of rotation by a certain distance. This distance is the distance measured perpendicular to the first axis of rotation from the first axis of rotation to the second axis of rotation at the level of the pump rotor.It has been found that even a small center-to-center distance of a maximum of 10 mm, in particular a maximum of 5 mm, and especially a maximum of 2.5 mm, is sufficient to achieve adequate pumping efficiency, which further improves the compactness of the pump device. In particular, it may already be sufficient if the outer rotor has a maximum diameter of no more than 50 mm, and especially no more than 35 mm.

[0019] According to an advantageous embodiment, the second housing part has an annular first sealing projection on the motor side. This first sealing projection overlaps axially without contact with a second sealing projection of the drive rotor, which points axially towards the second housing part, over a sealing area to provide a gap seal for separating an inner flow area from an outer flow area. Due to the lengthening of the flow path through a sealing gap between the first and second sealing projections, which at least radially separates the first and second sealing projections and whose cross-sectional area is reduced compared to adjacent areas, the gap seal increases flow resistance compared to adjacent areas. In operation, this creates an approximately fluid-tight seal.This allows for effective and, in particular, improved cooling of the motor area despite the compact design of the pump device. The pump device is preferably configured to guide fluid along each sealing projection in different, and especially opposite, directions on both sides. A flow region is defined as a region through which fluid can flow or through which fluid flows during operation of the pump device. The flow region is thus designed, at least as part of a cavity. The inner and outer flow regions are, in particular, each bounded by the first and second sealing projections. The second sealing projection is preferably manufactured by overmolding and / or from plastic. In particular, the first sealing projection is designed as an integral part of the second housing section.In particular, the first sealing projection is made of metal. By providing the sealing projections as described above, a non-contact seal similar to a labyrinth seal can be created, allowing fluid to be directed along defined areas of the drive rotor and / or into defined areas of the engine compartment.

[0020] This particularly favorably provides a flow path along which fluid flows successively along a radial inner side of the drive rotor and along a radial outer side.

[0021] According to an advantageous embodiment, the second housing part has at least one fluid channel, which in particular extends radially away from the drive shaft, for the fluid-carrying connection of the pump chamber in the pump area with a rotor receiving chamber in the motor area to provide a flow path for fluid from the pump chamber through the rotor receiving chamber to a low-pressure side of the pump chamber. The drive rotor is arranged in the rotor receiving chamber. In particular, the rotor receiving chamber is fluid-tightly separated from a stator area in which the drive stator is arranged. On the low-pressure side, during operation of the pump device, fluid is pressurized at a lower pressure than on a high-pressure side of the pump chamber, the pressure difference between the high-pressure side and the low-pressure side being generated by the pumping of fluid through the pump rotor. A pressure difference of, for example, 1 to 3 bar has already proven to be sufficient.During operation, fluid is drawn in at the inlet on the low-pressure side and discharged at the outlet on the high-pressure side. Specifically, the flow path runs from the pump chamber through the outer flow region and then through the inner flow region to the low-pressure side. Preferably, the drive rotor has several circumferentially distributed cooling channels that are radially arranged between the drive shaft and a magnetic section in which the drive rotor is located. These channels magnetically interact with the drive stator to apply torque to the drive shaft, particularly so that fluid can flow through the openings along the flow path to the low-pressure side. Most preferably, the drive rotor in the magnetic section comprises several permanent magnet components, the magnet components being uniformly distributed around the circumference of the drive rotor.Particularly preferably, the second housing part has a further fluid channel for the flow path, wherein the further fluid channel is arranged radially spaced from the fluid channel, and wherein, in particular, the first sealing projection is arranged radially between the further fluid channel and the fluid channel. In particular, the fluid channel and the further fluid channel are arranged circumferentially offset. In suitable embodiments, one of the fluid channels can be arranged on the low-pressure side and the other on the high-pressure side. This maximizes the pressure difference. However, in some embodiments, this is neither necessary nor desirable to obtain a sufficiently efficient pumping action from the inlet to the outlet.

[0022] Therefore, both fluid channels are particularly preferably arranged offset on the low-pressure side.

[0023] According to a particularly advantageous embodiment, which enables particularly compact designs, at least one end, in particular a section, of the fluid channel and / or the further fluid channel is arranged, with respect to the axis of rotation, on a side of the pump chamber where the pump chamber side wall has its greatest radial distance to the drive shaft. At least in the gerotor embodiment, the pump chamber side wall can extend eccentrically around the drive shaft, resulting in a defined location along the circumference where the radial distance to the drive shaft is maximized and an opposite location where the radial distance to the drive shaft is minimized.

[0024] By providing the fluid channel and, in particular, the flow path as described above, a fluid flow can be established in the engine area, thereby providing a system for lubrication and / or heat dissipation from the engine area. Thus, cooling of the engine components and / or adjacent components is also possible by means of the fluid pumped by the pump device.

[0025] According to one embodiment, the pump rotor is designed, arranged in the pump chamber, and fixedly connected to the drive shaft in such a way that the axial position of the drive rotor, and in particular the axial position of the drive shaft, is defined by means of the pump rotor. For this purpose, the pump rotor has an axial extent that corresponds to a corresponding axial extent of the pump chamber, in particular such that any axial movement of the drive shaft is limited to a negligible axial play of the pump rotor in the pump chamber with respect to the axial position of the drive rotor.Preferably, the pump rotor, when its axial side rests against a pump chamber wall bounding the pump chamber, is spaced from the axially opposite pump chamber by a maximum of 0.3 mm, particularly a maximum of 0.2 mm, particularly a maximum of 0.1 mm, and / or a maximum of 3%, particularly a maximum of 2%, of its maximum axial extent. The pump rotor, which is preferably designed as an internal rotor, preferably forms at least one axial bearing surface on each of its two axial sides. One of these axial bearing surfaces, in conjunction with a counter bearing surface formed by the first housing part and / or a counter bearing surface formed by the second housing part, provides an axial bearing. The axial bearing determines the axial position of the pump rotor, the drive rotor, and the drive shaft relative to the first housing part and / or the second housing part.In particular, the axial bearing is designed to be lubricated by fluid in the pump chamber, especially in such a way that, during operation of the pump device, the axial distance of the drive rotor to the second housing part is less when the pump rotor is rotating than when the pump rotor is stationary.

[0026] This embodiment integrates the function of a normally separate axial bearing into the existing components of the pump device. In particular, the drive rotor is cantilevered over the drive shaft in the motor area. This eliminates the need for end-mounted support of the drive shaft in the motor area, further simplifying the manufacturing of the pump device. Specifically, the drive rotor is axially supported solely by the pump rotor.

[0027] According to one embodiment, the first housing part has a passage from the pump chamber to the outside of the first housing part. The passage preferably has a cylindrical, and in particular circular, cross-section, which extends symmetrically around the axis of rotation. In particular, the passage is arranged coaxially with the bearing for the rotatable mounting of the drive shaft. The drive shaft is rotatably mounted in the passage with an end section. The end section preferably forms an axial end of the drive shaft. The end section extends axially from one axial end of the drive shaft over at least 7%, in particular at least 10%, and in particular a maximum of 20%, of the drive shaft. In particular, the axial extent of the end section of the drive shaft is at least 0.5 times, in particular at least 1 time, and in particular a maximum of 1.5 times, the diameter of the drive shaft in the region of the end section.In particular, the end section extends from the end of the drive shaft to the pump rotor, which is preferably designed as an internal rotor. Preferably, the drive shaft is supported by a plain bearing, such that the drive shaft and its end section are inserted into the passage in such a way that the end section, together with the bearing for the drive shaft, defines a radial position of the drive shaft. In particular, the end section of the shaft and the passage of the first housing part are designed to correspond to each other in such a way that lubrication for the plain bearing can be provided by fluid that can enter a fluid gap between the first housing part and the drive shaft in the passage from the pump chamber. Preferably, the end section extends to an outer surface of the pump device. In particular, the passage extends to the outer surface with at least a constant cross-section.The passage, with a cross-section increasing at least along a section extending to the outside, is particularly preferred. Providing this passage allows for simple mounting of the drive shaft on the first housing part and ensures that tilting of the pump rotor in the pump chamber is completely prevented. According to a preferred embodiment, instead of the passage, a recess open to the pump chamber can be provided in the first housing part, which prevents fluid from escaping during lubrication of the drive shaft as described above.

[0028] According to a preferred embodiment, the drive shaft is rotatably mounted between the pump rotor and the drive rotor in a sliding bearing section integrally formed with the second housing part. This sliding bearing section preferably forms the bearing of the second housing part described above for the rotatable mounting of the drive shaft. In particular, the sliding bearing section provides a fluid-carrying connection between the pump chamber, especially the high-pressure side, and the rotor mounting area. Specifically, fluid can be brought into contact with the drive shaft, at least partially, in the area of ​​the sliding bearing section, through this fluid-carrying connection between the pump chamber and the rotor mounting area, thus providing lubrication between the sliding bearing section and the drive shaft. In particular, the sliding bearing section is designed in the manner of a hydrostatic bearing.By providing the sliding bearing section, a simple and robust sliding bearing for the drive shaft is created, while simultaneously lubricating the sliding bearing and, in particular, enabling fluid exchange between the pump chamber and the rotor mounting chamber.

[0029] In one embodiment, the second housing part, on the motor side, has a guide projection, preferably integral, which surrounds the drive shaft in an annular manner and extends axially from the sliding bearing section to the drive rotor. The end of the sliding bearing section facing the drive rotor is thus preferably spaced apart from the drive rotor. In this embodiment, the guide projection, with its radial inner surface facing the drive shaft, is at least partially spaced away from the drive shaft to provide a free cross-section between the drive shaft and the guide projection. In particular, the free cross-section increases at least partially in the direction of the drive rotor. The guide projection is specifically designed to guide fluid away from the drive shaft along the flow path.In particular, the guide projection is designed to direct fluid flowing from the sliding bearing section away from the second guide element and towards the drive rotor. This allows fluid from the sliding bearing section to merge with fluid flowing along the flow path at a distance from the sliding bearing section. The guide projection also facilitates improved assembly of the second housing part and the drive shaft. Furthermore, the guide projection guides the drive shaft into the sliding bearing section during insertion. The fluid flow is optimized, especially when, during pump operation, fluid flows in different, and particularly opposite, directions on both radial sides of the guide projection.

[0030] According to a preferred embodiment, the pump device further comprises a pipe section in the motor area, which is formed in particular by a canned tube, and more preferably by a canned housing. The pipe section is designed to separate the rotor mounting chamber fluid-tight from the stator area in which the drive stator is arranged, by providing an annular gap for fluid between the pipe section and the drive rotor. In particular, the flow path runs through the annular gap. In preferred embodiments, the pipe section further comprises a flange area that bears against the second housing part, at least partially, and in particular axially, over a flat surface. This ensures effective fluid tightness between the second housing part and the flange element. The flange area extends radially, in particular, from the subsection of the pipe section where the annular gap is formed.

[0031] The pipe section and the second housing part are preferably designed to correspond such that a vertically extending and a horizontally extending subsection of the pipe section each bear against the second housing part over a flat area, particularly continuously, particularly over at least 20%, particularly at least 40%, particularly at least 70% of the radial extent of the flange area. According to one embodiment, the pipe section, the first housing part, and the second housing part are designed to correspond and are arranged one another in such a way that the pipe section, the first housing part, and the second housing part together enclose a space, wherein at least one elastic, particularly rubber-elastic, and particularly elastomeric, sealing element is arranged in the space. Preferably, the sealing element is designed as a sealing ring, and particularly preferably as an O-ring.

[0032] A bottom section, particularly one integral with the pipe section, is preferably connected to the pipe section. The bottom section separates an electronics section of the pump device from the motor section. An electronic control unit is preferably arranged in the electronics section. In particular, the control unit comprises a printed circuit board, which is thermally connected to the bottom section directly and / or by means of a thermal interface material. This allows waste heat from the control unit, especially the printed circuit board, to be transferred to the fluid in the motor section and carried away from the pump device by the fluid.

[0033] Advantageously, the pump device further comprises an electrical connector for electrical and / or electronic connection to external components. In particular, the pump rotor and the connector are arranged on axially opposite sides of the drive rotor. Preferably, the circuit board and the connector are arranged on the same axial side of the drive rotor. Particularly preferably, the circuit board is arranged axially between the drive stator and the connector. The connector comprises, in particular, electrical contacts that are electrically connected to the drive stator and / or the circuit board. Preferably, the drive stator is electrically and / or electronically connected to the connector via the circuit board.

[0034] According to one embodiment, the housing structure comprises a third housing part that is connected to the second housing part and surrounds the motor area, overlapping the drive rotor and the drive stator at least axially. Preferably, the third housing part comprises at least one housing section manufactured by injection molding. This allows for greater design freedom and enables cost-effective manufacturing of the housing structure. Preferably, the third housing part is multi-part, with a first housing section of the third housing part preferably surrounding the motor area, overlapping the drive rotor and the drive stator axially, and a second housing section of the third housing part being attached to the first housing section as a housing cover, sealing off the electronics area at least axially. This protects the electronics area from external elements.In particular, the third housing part comprises an opening to the outside sealed by a membrane, wherein the membrane is preferably liquid-tight and vapor-permeable. Preferably, the membrane is made of a material comprising expanded PTFE (expanded polytetrafluoroethylene). Its nanofibrillar structure has proven particularly effective in providing the desired membrane properties.

[0035] According to one embodiment, the first housing part comprises circumferentially, and in particular uniformly, distributed fastening projections on its radial outer surface, wherein the third housing part comprises corresponding fastening means, in particular integrally formed, which each interact positively and / or frictionally with the respective fastening projection to fasten the third housing part to the first housing part. Particularly preferably, the respective fastening projections and the respective fastening means interact, and the first and third housing parts are designed and arranged relative to each other, such that the second housing part, and in particular the pipe section, is fixed in its respective position relative to the first housing part and / or the third housing part.

[0036] Preferably, the inlet and outlet are arranged axially next to the pump rotor. In particular, the inlet is designed as an inlet nozzle and the outlet as an outlet nozzle, each extending axially away from the pump chamber. It is generally advantageous for the inlet and outlet to be integrally formed with the first housing part. Preferably, the inlet nozzle is arranged on the low-pressure side. Preferably, the outlet nozzle is arranged on the high-pressure side. The axial arrangement next to the pump chamber has proven advantageous for a compact radial installation space. Thus, the first housing part preferably extends radially beyond the respective inlet, in particular the inlet nozzle, and outlet, in particular the outlet nozzle. This ensures that the inlet and outlet are each spaced from a radial end of the first housing part.In particular, the inlet and outlet are arranged relative to each other in such a way that the drive shaft is arranged radially between the inlet and outlet.

[0037] In generally preferred embodiments, the pump device has features that are disclosed above in connection with known pump devices.

[0038] One aspect of the invention further relates to a motor vehicle, which preferably has an electric drivetrain comprising an electric motor for propelling the motor vehicle. According to the invention, the motor vehicle includes a pump device with the features described above in connection with the invention.

[0039] Further details, advantages and features of the invention can be found, without limiting the generality of the foregoing description, in the following part of the description, in which exemplary embodiments are explained in more detail with reference to the attached figures.

[0040] They show: Fig. 1: A first sectional view of a first embodiment of a pump device according to the invention; Fig. 2: a second sectional view of the first embodiment; Fig. 3: a sectional view of the first embodiment of the pump device in three-dimensional representation; Fig. 4: Several views of a second housing part for a pump device according to the first embodiment; Fig. 5: Several views of a first housing part for a pump device according to the first embodiment; Fig. 6: a sectional view of a second embodiment of a pump device according to the invention in three-dimensional representation.

[0041] For better understanding, identical parts within the meaning of the invention are provided with the same reference numerals.

[0042] Fig. Figure 1 shows a schematic first sectional view of a first embodiment of a pump device according to the invention. The pump device is designed as a gerotor pump and comprises a pump rotor 41 with external teeth, which is designed as the inner rotor of a gerotor, and a further pump rotor 42, which is designed as the outer rotor of the gerotor and has internal teeth corresponding to the external teeth. The outer rotor and inner rotor are each rotatable about different axes of rotation D, D', i.e., the pump rotor 41 about the axis of rotation D and the further pump rotor 42 about the further axis of rotation D'. The pump device is shown in the view of Fig. Figure 1 shows the pump rotors cut at the level of the axis of rotation D such that the axis of rotation D and the further axis of rotation D' are arranged one behind the other. The pump rotors 41, 42 mesh with each other with their respective external and internal teeth, respectively, forming pumping zones whose respective volumes are variable for pumping fluid between inlet 15 and outlet 16. The pump device further comprises an electric drive unit 6 for driving the pump rotor 41, wherein the drive unit 6 comprises a drive stator 61 and a drive rotor 62, which interact in the manner of an electric motor. The pump rotor 41 and the drive rotor 62 are each pressed onto a drive shaft 7 in a positionally fixed manner. The drive shaft 7 is designed as a solid shaft and is rotatably mounted between the pump rotor 41 and the drive rotor 62 about the axis of rotation D in a sliding bearing section 23 of the second housing part 2.

[0043] The pump device comprises a housing structure with a first housing part 1 and a second housing part 2. The first housing part 1 and the second housing part 2 are made of the same material to minimize differences between the coefficients of thermal expansion of the first housing part 1 and the second housing part 2. The second housing part forms a partition to divide the pump device into a pump section 101 and a motor section 102. The drive unit 6 is located in the motor section. The pump rotors 41, 42 are located in the pump section. The first housing part 1 encloses the pump section 101 by forming an outer casing and by providing nozzles as an inlet 15 and an outlet 16.The first housing part 1 forms an axial end of the housing structure on one side, namely in the form of the nozzle for the outlet 16, to which a sealing ring is attached, and on its opposite side a recess 11, which provides a pump chamber 8 within the pump area 101. The pump rotors 41, 42 are rotatably arranged in the pump chamber 8. The outer rotor is radially supported by the first housing part 1 with its radial outer surface and axially supported by the first housing part 1 and the second housing part 2 at its respective axial end faces in one axial direction.

[0044] The first housing part 1 and the second housing part 2 are connected in a positionally fixed manner by means of a press fit. For this purpose, the second housing part 2 is axially inserted into the first housing part 1 and rests axially against the first housing part 1 along a contact plane E at the end of the pump chamber 8. The first housing part 1 forms a skirt-like, annular first fixing projection 12 at its radial end. The second housing part 2 forms an annular second fixing projection 21 at one radial end, which extends axially away from the contact plane E. To form the press fit, the fixing projections 12 and 21 are pressed radially together. The second fixing projection 21 is arranged in a fixing groove 13 between the first fixing projection 12 and the pump chamber 8.

[0045] The drive rotor 62 is arranged in a rotor mounting chamber 9, which is fluidly connected to the pump chamber 8, which is generally advantageous. The fluid connection is created by the second housing part 2 in the form of a fluid channel 22. Through the fluid channel 22, fluid can flow from the pump chamber 8 through the rotor mounting chamber 9 and through a further fluid channel 26 (not shown in the figure). Fig. 1) Flow back to the pump chamber 8. The rotor receiving chamber 5 is fluid-tightly separated from a stator area, in which the drive stator 61 is arranged, by a pipe section 5 in the motor area 102. This provides an annular gap for fluid between the pipe section 5 and the drive rotor 62. The pipe section 5 is part of a containment shell, on the bottom section of which a circuit board of an electronic control unit for controlling the pump device is arranged for dissipating waste heat to fluid in the motor area. The drive stator 61 is arranged in a first housing section 31 of a third housing part 3 of the housing structure. A second housing section 32 of the third housing part 3, acting as a housing cover, closes off an electronics area for the control unit to the outside.

[0046] Fig. Figure 2 shows a second schematic sectional view of the first embodiment, the cross-sectional surface of which is perpendicular to that of Fig. 1 is running. Fig. Figure 3 shows a third schematic sectional view of the first embodiment, the cross-sectional surface of which is offset from the first. Unlike in Fig. With the exception of the first housing part 1, the second housing part 2, the pipe section 5 designed as a containment shell, the pump rotors 41, 42, the drive shaft 7, and the drive rotor 62, all components of the pump device are not shown. The pipe section 5 has a flanged area 51 at its axial end, which rests flat against the second housing part 2. The flanged area 51, the first housing part 1, and the second housing part 2 together enclose a space in which a sealing ring is arranged (see Fig. 1) to further reduce the risk of leakage. An additional sealing ring can also be arranged on the opposite side of the flange area 51. On the motor area 102 side, an annular first sealing projection 24 of the second housing part 2 and an annular second sealing projection 621 of the drive rotor 62 overlap without contact over a sealing area. This creates a gap seal to separate an inner flow area 91 from an outer flow area 92 in the rotor receiving chamber 9. In the outer flow area 92, fluid can flow from the pump chamber 8 past the sealing projections 24, 621 through the annular gap, whereupon the fluid can be deflected at the bottom section and flow in the inner flow area 91 through the drive rotor, past the sealing projections 24, 621, and back to the pump chamber 8.During operation, fluid flows as intended from the pump chamber 8 through a fluid channel 26 along a flow path S to a region axially located between the drive rotor 62 and the bottom section of the pipe section. It then flows through circumferentially distributed cooling channels of the drive rotor 62, past the sealing projections 24, 621, and through a fluid channel 22 back into the pump chamber 8. The cooling channels run radially between the drive shaft 7 and a magnetic area in which the drive rotor 62 has several permanent magnet components. During operation, these components interact magnetically with the drive stator 61 to generate torque or rotation about the axis of rotation D. In principle, and advantageously in some embodiments, fluid can flow in the opposite direction along the flow path S instead of following the path described above.However, this is less preferred due to less favorable pressure conditions in the area of ​​the annular gap.

[0047] A guide projection 25 is formed between the first sealing projection 24 and the drive shaft 7. This guide projection 25 surrounds the drive shaft 7 in an annular manner and extends axially from the sliding bearing section 23 to the drive rotor 62. The guide projection 25 is spaced further from the drive shaft 7 than the sliding bearing section 23. Since a portion of the fluid from the pump chamber 8 is intended to flow along the drive shaft 7 for lubrication in the area of ​​the sliding bearing section 23, the guide projection 25 forms a partial separation between the fluid used for lubrication and the fluid flowing back to the pump chamber 8. In addition to the support of the drive shaft 7 in the sliding bearing section 23, a further support point for the radial end support of the drive shaft 7 is provided through the first housing part 1 by means of a passage 14. The shaft is rotatably supported in the passage 14 with an end section 71 that extends to the outside of the first housing part 1.Here too, fluid from the pump chamber provides lubrication for the sliding bearing.

[0048] Fig. 4, comprehensive Fig. 4a to 4d, shows in four views, of which in Fig. 4b and Fig. Figure 4c shows a sectional view of a second housing part 2 for the pump device in three dimensions. The housing part 2 is manufactured in one piece with a circular outer contour formed by the second fixing projection 21. A contact surface of the second fixing projection 21 is formed around its radial outer surface to abut a corresponding contact surface of the first fixing projection 12. Radially between the second fixing projection 21, or rather its contact surface, and the first sealing projection 24, a further annular projection is formed, creating both an axial and a radial contact surface for the pipe section 5. This allows a vertically extending and a horizontally extending subsection of the pipe section 5 to bear against the second housing part 2 in a continuous contact area.

[0049] A fluid channel 22, 26 is formed on each side of the sealing projection 24. Each fluid channel 22, 26 advantageously has a kidney-shaped opening cross-section. The fluid channels 22, 21 are arranged offset along the circumference, with one of the fluid channels 22 being located opposite the high-pressure side with respect to the axis of rotation D, and the other fluid channel 26 being arranged sectionally in a region that is radially opposite a region of the pump chamber 8 with respect to the axis of rotation D, where the radial distance between a radial end of the pump chamber 8 or the recess 11 and the axis of rotation D is minimal. This makes advantageous use of the available installation space. On one side opposite the fluid channels 22, 26 with respect to the axis of rotation D or the sliding bearing section 23, the second housing section 2 has a recess that is enlarged radially in the direction of the outlet 16 of the pump device.This recess is fluidly connected to the sliding bearing section 23 via a radially extending groove, allowing fluid to reach the sliding bearing section 23 for lubrication. The recess has an axial depth that increases radially, and in particular continuously, towards the sliding bearing section 23.

[0050] The sliding bearing section 23 in the center of the second housing part 2 for supporting the drive shaft 7 has a smooth bearing surface for the drive shaft 7. However, it is also conceivable to provide a grooved bearing surface or channels open to the drive shaft. At least in sections between the fluid channel 22 and the sliding bearing section 23, an annular guide projection 25 is formed. The guide projection 25 is designed to provide a free cross-section between the drive shaft 7 and the guide projection 25.

[0051] Fig. 5 comprehensive Fig. Figures 5a to 5c show three schematic views, including one sectional view. Fig. 5b, a housing part 1 for the pump device according to the first embodiment. The housing part 1 and the second housing part 2 are each manufactured in one piece from sintered metal. In the radial center of the first housing part 1, the passage 14 is provided as a bearing point for the drive shaft 7. To improve the supply of fluid from the pump chamber for lubrication, the first housing part 1 has a radially extending groove for fluid connection with the recess 11 for the pump chamber 8. On both sides of the passage 14, a nozzle is formed as an inlet 15 and an outlet 16, respectively. The inlet 15 and outlet 16 are each arranged axially next to the recess 11, which is generally advantageous. The recess 11 has a kidney-shaped area towards the inlet 15 and the outlet 16 for reliable fluid introduction into the conveying areas formed between the pump rotors 41, 42.

[0052] The generally advantageous, skirt-shaped first fixing projection 12 forms a radial end of the first housing part 1, with several fastening projections distributed along its circumference being formed on the fixing projection 12. These fastening projections allow for locking with corresponding fastening means of the third housing part 3. The fixing projection forms a first groove wall of the fixing groove 13. A second groove wall, radially inner and pointing away from the axis of rotation, is interrupted in the region of the outlet 16. In the region of the inlet 15, however, the groove bottom of the fixing groove 13 is interrupted, thus providing a fluid connection between the inlet 15 and the fixing groove 13, which is generally advantageous.The section of the first housing part 1 forming the second groove wall extends in a web-like fashion over the area in which the groove bottom is interrupted in order to provide a reliable radial bearing for the further pump rotor 42 designed as an outer rotor.

[0053] Fig. Figure 6 shows a schematic sectional view of a second embodiment of a pump device according to the invention in three dimensions. The pump device has significant similarities to the pump device of the first embodiment, which is why only some special features of the second embodiment will be discussed below.

[0054] The drive shaft 7 is supported by means of the sliding bearing section 23 and, instead of the through-hole 14, by a recess open to the pump chamber 8 in the first housing part 1. The further pump rotor 42, designed as the outer rotor of a gerotor, has an end-face seal with both the first housing part 1 and the second housing part 2. The first housing part 1 extends bell-shaped around the pump chamber 8 and, with its first fixing projection 12, beyond the pump area 101. The axial absolute end of the first housing part 1, facing away from the outlet 16 or inlet 15, is located at the level of the drive stator 62. The first housing part 1 has several mounting lugs at the level of the drive stator 62 for attaching the pump device to or in a motor vehicle, which form an absolute radial end of the first housing part 1, which is generally advantageous.

[0055] A third housing part 3, designed as a cover for an electronics area containing a circuit board of an electrical control device, is attached to the first housing part 1. The third housing part has an electrical connector for electrical connection to external components, with the drive stator 62 being electrically connected to the connector via the circuit board.

[0056] The second housing part 2 has a second fixing projection 21, which extends axially towards the drive stator 62 from the contact plane E, along which the first housing part 1 and the second housing part 2 abut axially, and is pressed against the first fixing projection 12 to fix the first housing part 1 and the second housing part 2 to one another. Accordingly, a fixing groove 13 as in the first embodiment is omitted. Furthermore, measures for improved fluid flow through the motor compartment 102, such as a non-contact seal by means of the first and second sealing projections 24, 621, are also omitted. Reference symbol list 1 first housing part 2 second housing part 3 third housing part 5 Pipe section 6 Drive unit 7 Drive shaft 8 Pump chamber 9 Rotor mounting space 11 In-depth study 12 first fixing protrusion 13 Fixing groove 14th round 15 Admission 16 Outlet 21 second fixing projection 22 Fluid channel 23 Sliding bearing section 24 first density advantage 25% lead 26 additional fluid channels 31 first housing section of the third housing part 32 second housing section of the third housing part 51 Flange area 41 Pump rotor 42 additional pump rotors 61 Drive stator 62 Drive rotor 71 Final section 91 inner flow area 92 outer flow area 101 Pump area 102 Engine area 621 second density advantage D axis of rotation D' axis of rotation S flow path QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 102021130216A1

[0006]

Claims

[1] Electric pumping device for a motor vehicle comprising, at least one pump rotor (41) designed to pump fluid, in particular a lubricant and / or a coolant, from an inlet (15, 16) to an outlet (15, 16); an electric drive device (6) for driving the pump rotor (41), wherein the drive device (6) comprises a drive stator (61) and a drive rotor (62), wherein the pump rotor (41) and the drive rotor (62) are each fixedly connected to a common drive shaft (7), wherein the drive shaft (7) is rotatably mounted between the pump rotor (41) and the drive rotor about an axially extending axis of rotation (D); a housing structure comprising a first housing part (1) and a second housing part (2) which divides the pump device into a pump area (101) and a motor area (102), wherein the first housing part (1) closes off the pump area (101) and forms a radial outer surface of the pump device in an overlap area in which the first housing part (1) axially overlaps with the second housing part (2), wherein the first housing part (1) forms an axial end of the housing structure on one side and has a recess (11) on its opposite side through which a pump chamber (8) is provided within the pump area (101), wherein the at least one pump rotor (41), in particular each, is rotatably arranged in the pump chamber (8), wherein the second housing part (2) is axially inserted into the first housing part (1) by forming a press connection with the first housing part (1) and rests axially against the first housing part (1) along a contact plane (E) to close off the pump chamber (8), wherein the first housing part (1) has an annular first fixing projection (12) at a radial end and the second housing part has an annular second fixing projection (21) at a radial end, which extends axially away from the contact plane (E), wherein to form the press connection the second fixing projection (21) is pressed radially against the first fixing projection (12). [2] Pump device according to claim 1, wherein the first housing part (1) has a fixing groove (13) pointing axially to the second housing part (2), which is arranged between the first fixing projection (12) of the first housing part (1) and the pump chamber (8), wherein the second fixing projection (21) is arranged in the fixing groove (13). [3] Pump device according to claim 1 or 2, wherein which at least one pump rotor (41) is designed as an inner rotor of a gerotor which has external teeth, wherein the pump device has a further pump rotor (42) which is arranged in the pump chamber (8), wherein the further pump rotor (42) is designed as an outer rotor of the gerotor which has an internal toothing corresponding to the external toothing, wherein the outer rotor and the inner rotor are arranged eccentrically to each other. [4] Pump device according to one of claims 1 to 3, wherein the second housing part (2) has an annular first sealing projection (24) on the side of the motor area (102) which axially overlaps without contact with a second sealing projection (621) of the drive rotor (62) extending axially to the second housing part over a sealing area to provide a gap seal for separating an inner flow area (91) from an outer flow area (92). [5] Pump device according to one of the preceding claims, wherein the second housing part (2) has at least one fluid channel (22) for fluid-carrying connection of the pump chamber (8) in the pump area (101) with a rotor receiving space (9) in the motor area (102) to provide a flow path (S) for fluid from the pump chamber (8) through the rotor receiving space (9) to a low-pressure side of the pump chamber (8), wherein in particular the flow path (S) runs from the pump chamber (8) through the outer flow area (92) and then through the inner flow area (91) to the low-pressure side. [6] Pump device according to one of the preceding claims, wherein the pump rotor (41) is designed, arranged in the pump chamber and connected to the drive shaft (7) in a position-fixed manner such that an axial position of the drive rotor (62) is determined by means of the pump rotor (41). [7] Pump device according to one of the preceding claims, wherein the first housing part (1) has a passage (14) from the pump chamber (8) to the outside of the first housing part (1), wherein the drive shaft (7) is rotatably mounted in the passage (14) with an end section (71). [8] Pump device according to one of the preceding claims, wherein the drive shaft (7) is rotatably mounted between the pump rotor (41) and the drive rotor (62) in a sliding bearing section (23) integrally designed with the second housing part (2), wherein in particular the sliding bearing section (23) provides a fluid-carrying connection between the pump chamber (8), in particular the high-pressure side, and the rotor receiving area (9). [9] Pump device according to one of the preceding claims, further comprising a pipe section (5) in the motor area (102) which is designed to separate the rotor receiving space (9) fluid-tight from a stator area in which the drive stator (61) is arranged, providing an annular gap for fluid between pipe section (5) and drive rotor (62), wherein the pipe section (10) has a flange area (51) which at least partially rests against the second housing part (2). [10] Motor vehicle comprising a pump device according to any one of claims 1 to 9.

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