Apparatus for transferring liquids

Abstract

To provide a liquid transfer device, specifically a gerotor pump, with a larger theoretical transfer volume but with the same or reduced required footprint. The present invention relates to a gerotor pump, a device for transferring liquids. The device includes a housing having a flange enclosing a volume, an outer rotor mounted for rotation about a longitudinal axis and an inner rotor of a displacement mechanism, and an electric drive rotor. The electric drive rotor is integrally formed with the outer rotor. The flange is also integrally formed with an eccentric for receiving the inner rotor and a conical bearing member extending in the direction of the longitudinal axis for receiving the outer rotor. The present invention relates to the use of the device for transferring liquids in a vehicle, for lubricating and cooling gears using oil or liquid, or for cooling a battery or an electric engine.

Description

[Technical field]

[0001] The present invention relates to a liquid transfer device, a gear pump, more particularly an annular gear pump or gerotor pump. The device comprises a housing enclosing a volume and including a flange, an outer rotor mounted for rotation about a longitudinal axis, an inner rotor of a displacement mechanism, and an electric drive rotor. The electric drive rotor is integrally formed with the outer rotor of the displacement mechanism. The device is preferably used in a motor vehicle to lubricate and cool gears using oil as a liquid. [Background technology]

[0002] Gear pumps known from the prior art, in particular annular gear pumps, also called gerotor pumps, have an inner rotor and an outer rotor. The outer rotor can be formed integrally connected to the rotor of an electric drive, in particular an electric motor. The rotor is arranged in a housing closed by a flange. The rotor of the electric motor of the gerotor pump and the outer rotor of the displacement mechanism are fixed to a rotatably mounted shaft.

[0003] The shaft is supported by the flange through bearings. The shaft is mounted in the flange area in an axially oriented opening in the eccentric. The eccentric is integrally formed with the flange as part of it. The inner rotor is driven by the outer rotor and guided from the outside of the eccentric. The liquid is transported from the suction area or inlet to the pressure area or outlet in an intermediate space, also called the gerotor cell, provided between the outer and inner rotors.

[0004] German patent DE 10 2019200560 A1 discloses a gerotor pump of this type, in which the rotor of the electric motor and the associated shaft of the outer rotor of the displacement mechanism are formed separately. The shaft is designed as a hollow shaft with an axially oriented through opening as a pressure equalization device. This ensures pressure equalization between the motor space, which is the volumetric area surrounded by the housing and in which the rotor of the electric motor is located, and the suction area formed inside the flange.

[0005] For example, liquids such as gear lubricants can flow from the motor space into the suction area as leakage flow through through openings in the hollow shaft that are fitted with plates to minimize leakage. In addition to pressure equalization, leakage flow can also be used, for example, to cool the controls of gerotor pumps.

[0006] To ensure sufficient strength of the flange, the bearing of the hollow shaft inside the axial opening of the flange and the bearing of the internal rotor outside the eccentric as part of the flange require a certain wall thickness of the eccentric between the inside and outside of the eccentric. Also, the minimum outer diameter of the shaft is limited by the inner diameter of the through opening formed in the shaft. The required wall thickness of the eccentric and the required inner diameter of the through opening formed in the shaft limit the minimum diameter of the contour of the internal rotor, especially the root diameter, and ultimately the possible conveying volume of a gerotor pump with the same space. As a result, the conveying volume of the gerotor pump can be increased while keeping the number of gerotor cells the same, simply by increasing the outer diameter of the external rotor and the housing. However, in this case the installation space of the gerotor pump will be larger. Summary of the Invention [Problem to be solved by the invention]

[0007] The object of the present invention is to provide a liquid transfer device, in particular a gerotor pump, which has a larger theoretical transfer volume but requires the same or a reduced footprint than devices known from the prior art. The device should be simple to manufacture and can be assembled in a time-saving manner. [Means for solving the problem]

[0008] This object is achieved by subject matter having the features of the independent claims, with further developments being set out in the dependent claims.

[0009] The object of the invention is achieved by a liquid transfer device, in particular a gerotor pump, according to the invention, which includes a housing having a flange enclosing a volume, an outer rotor mounted for rotation about a longitudinal axis, an inner rotor of a displacement mechanism, and an electric drive rotor, the electric drive rotor being integrally formed with the outer rotor of the displacement mechanism.

[0010] In accordance with the concept of the present invention, the flange has an eccentric portion for receiving the inner rotor and a longitudinally extending pile-like bearing member for receiving the outer rotor. In accordance with the present invention, the flange is integrally formed with the eccentric portion and the bearing member. The outer rotor is mounted for rotation with the bearing member about the longitudinal axis and the inner rotor is arranged for rotation about an eccentric within the outer rotor. The rotor of the electric drive is mounted on a longitudinally oriented flanged pile bearing member for rotation with the outer rotor of the displacement mechanism about the longitudinal axis.

[0011] The integral molding of the flange, the eccentric and the bearing member results in the bearing member being fixed and immovable relative to the housing or the flange, being fixed and therefore non-rotatable. Integral molding means being formed of a single piece, for example a single part molded piece. However, integral molding also includes being formed of several pieces which are fixedly formed together, in particular pressed together.

[0012] The bearing member is preferably at least substantially cylindrical in shape with a constant outer diameter in the longitudinal direction. Moreover, the bearing member advantageously protrudes from a free end face of the eccentric part facing towards the housing. If the housing is formed in the shape of a substantially hollow cylinder with a closed first end face, the flange closes a second end face of the housing formed distally from the first end face.

[0013] According to an embodiment of the invention, the bearing member comprises on its lateral surface a first bearing surface for guiding a rotor of the electric drive together with the outer rotor, a second bearing surface for guiding an inner rotor driven by the outer rotor being preferably provided on the outside of the eccentric part.

[0014] According to an advantageous embodiment of the invention, the fluid connection of the device for pressure equalization is formed between the motor space and the suction area as a region of the volume enclosed by a housing with a flange, in which case the motor space together with the flange constitutes a first part of the volume enclosed by the housing, and the external rotor and the internal rotor of the displacement mechanism are arranged in a second part of the volume.

[0015] According to a first alternative embodiment of the invention, the flange is part of the device for pressure equalization and includes an axial through-opening at least in the region of the bearing member and the eccentric. The through-opening preferably starts from the first free end face and extends axially to the interior of the bearing member. The through-opening is preferably oriented coaxially with the longitudinal axis of the device. The through-opening can be formed including a throttling device for the liquid.

[0016] The flange may include a flattened area within the region of the cylindrical eccentric, the flattened area being formed on an outer lateral surface of the eccentric.

[0017] According to a second alternative embodiment of the invention, the flange comprises flattened areas in the region of the cylindrical bearing member and in the region of the cylindrical eccentric, respectively. The flattened areas are formed on the respective outer lateral surfaces. In this case, the first flattened area extends axially over the entire length of the eccentric, starting from the first free end face and up to the second end face of the eccentric, which is integrated in the region of the flange where the eccentric closes the housing. Through the first flattened area, a flow passage is formed between the eccentric and the inside of the inner rotor of the displacement mechanism. The flange comprises a groove, which preferably extends radially and between the first flattened area and the suction area of ​​the device.

[0018] Another advantage of the invention is that the second flattened area starts from the first free end face and extends axially to a second end face of the bearing element, where the bearing element is eccentrically connected on the eccentric end face facing towards the housing. Via the second flattened area, a flow passage is formed between the bearing element and the inside of the rotor of the electric drive.

[0019] The second flattened region may extend axially continuously over the entire length of the bearing member. Alternatively, the second flattened region may be formed in at least two sections each extending axially over a portion of the length of the bearing member. In this case, the at least two sections of the second flattened region are preferably radially opposed to one another on the bearing member and axially offset from one another.

[0020] The flattened areas and grooves, respectively, formed on the outer diameter of the cylindrical bearing surface, are provided with flow passages as ramps or chamfers, as condensed leakage paths for the liquid. By adjusting the flow cross section between the chamfer and the bearing surface or groove, a throttling function can also be realized. The advantageous design of the present invention allows the use of devices for transporting liquids in vehicles, in particular devices for lubricating and cooling gears using oil or liquid, or devices for cooling batteries or electric engines. Effect of the Invention

[0021] In summary, the device according to the invention has various advantages: (a) Achieving a greater conveying amount in the same or a smaller installation area, or the same conveying amount in a smaller installation area, compared to previously known devices. (b) Minimization of components, e.g. no need for a rotor of the electric drive or a separately formed shaft to guide the external rotor compared to conventional devices, which also brings the following advantages: (c) Minimized production and assembly costs. [Brief description of the drawings]

[0022] Embodiments of the present invention will now be described with reference to the drawings in which: [Figure 1a] FIG. 1 is a side view of a gerotor pump according to the prior art, comprising a housing closed by a flange, an outer rotor arranged on a rotatably mounted shaft, an inner rotor, and a device for pressure equalization between the suction area and the motor space. [Figure 1b] FIG. 1 is a front view of a gerotor pump according to the prior art, comprising a housing closed by a flange, an outer rotor arranged on a rotatably mounted shaft, an inner rotor, and a device for pressure equalization between the suction area and the motor space. [Figure 2a] 1 shows a cross-sectional side view of a gerotor pump in which the external rotor is mounted on a pile-shaped bearing member formed integral with the flange. [Figure 2b] 1 shows a cross-sectional front view of a gerotor pump in which an outer rotor is mounted on a pile-like bearing member formed integrally with a flange. [Figure 2c] FIG. 2c shows a perspective view of a flange of the gerotor pump according to FIGS. 2a and 2b formed integrally with a bearing member for receiving the outer rotor; [Figure 3a]FIG. 1 shows a cross-sectional side view of a first embodiment of a gerotor pump in which the outer rotor is arranged on a pile-shaped bearing member formed integrally with the flange and having an axial through opening as a device for pressure equalization between the suction area and the motor space. [Figure 3b] FIG. 1 is a cross-sectional front view of a first embodiment of a gerotor pump in which the outer rotor is mounted on a pile-shaped bearing member formed integrally with the flange and having an axial through opening as a device for pressure equalization between the suction area and the motor space. [Figure 3c] 3a and 3b show a flange of the gerotor pump in a perspective view. [Figure 4a] FIG. 1 shows a second embodiment of a gerotor pump in cross section in side view, with a flattened area as a device for pressure equalization between the suction area and the motor space, and with an outer rotor mounted on a pile-shaped bearing member formed integrally with the flange. [Figure 4b] FIG. 1 shows a second embodiment of a gerotor pump in cross section at the front, with a flattened area as a device for pressure equalization between the suction area and the motor space, and with an outer rotor mounted on a pile-shaped bearing member formed integrally with the flange. [Figure 4c] 4a and 4b show a flange of the gerotor pump in a perspective view. [Figure 5a] FIG. 1 shows a third embodiment of a gerotor pump in which the external rotor is arranged on a pile-shaped bearing member formed integrally with a flange, having two mutually opposed and axially offset sections of the flattened area as a device for pressure equalization between the suction area and the motor space. [Figure 5b] FIG. 1 shows a third embodiment of a gerotor pump in which the external rotor is arranged on a pile-shaped bearing member formed integrally with a flange, having two mutually opposed and axially offset sections of the flattened area as a device for pressure equalization between the suction area and the motor space. [Figure 5c] 5a and 5b show a flange of the gerotor pump in a perspective view. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] 1a and 1b show a prior art liquid transfer device 1', in particular a gerotor pump, in side and front views. The device 1' consists of a housing 2 closed by a flange 3', an outer rotor 6 arranged on a rotatably mounted shaft 4', an inner rotor 7 and a device for equalizing the pressure between the motor space 2a and the suction area 8.

[0024] The cylindrical housing 2, being substantially hollow and cylindrical, has a first closed end face. A second end face, formed distally from the first end face, is closed by a flange 3'. The motor space 2a, in combination with the flange 3', constitutes a first part of the volume enclosed by the housing 2, while the outer rotor 6 and the inner rotor 7 of the displacement mechanism are arranged in a second part of the volume. Both parts together form the volume enclosed by the housing 2.

[0025] A rotor 21 of the electric motor 20 having rotor laminations 21a is disposed inside the motor space 2a of the housing 2. A stator (not shown) of the electric motor 20 has a stator lamination stack with coil windings, which are embedded in plastic together with the stator lamination stack. The plastic, for example molded using an injection molding process, forms the housing 2. The stator and rotor 21 of the electric motor 20 extend along a common longitudinal axis 5 that constitutes the axis of rotation of the rotor 21. The stator is located radially outside the rotor 21 and surrounds it. The flange 3' can likewise be formed of plastic, preferably the same plastic as the housing 2, or of metal.

[0026] The rotor laminations 21a together with the permanent magnets (not shown) are overmolded with plastic so that the rotor 21 of the electric motor 20 is integrally formed with the external rotor 6 of the displacement mechanism. As a result, both the rotor 21 of the electric motor 20 and the external rotor 6 of the displacement mechanism are formed of plastic so that the external rotor 6 is directly driven by the rotor 21 of the electric motor 20.

[0027] The rotor 21 of the electric motor 20 together with the external rotor 6 of the displacement mechanism is connected to a shaft 4' mounted for rotation about a longitudinal axis 5. The shaft 4' is supported on one side in the housing 2 and on the other side in the flange 3' via bearings in each case. The shaft 4' is mounted axially in the housing 2, radially and axially in the flange 3' and in the flange 3' area in the axially directed receiving opening 3b' of the flange 3'. The receiving opening 3b' is provided in the area of ​​the flange 3' formed by the eccentric part 3a'. The eccentric part 3a' is formed integrally with the flange 3' as part of the flange 3'.

[0028] The internal rotor 7, driven by the external rotor 6 of the displacement mechanism, is mounted outside the eccentric part 3a' independently of the external rotor 6 and is arranged so that the internal rotor 7 is eccentric with respect to the shaft 4' and the external rotor 6. The liquid to be transported by the device 1' is guided in an intermediate space provided between the internal rotor 7 and the external rotor 6 from the suction area 8, which is the inlet of the device 1', to the pressure area 9, which is the outlet of the device. The device 1' moves the liquid from a low pressure at the inlet to a high pressure at the outlet.

[0029] The liquid flows from the pressure area 9 into the motor space 2a of the device 1' through the gap left between the outer rotor 6 and the flange 3', thereby subjecting the liquid to a medium pressure level in the motor space 2a. The medium pressure present in the motor space 2a reduces the gap left between the outer rotor 6 and the flange 3' and increases the sealing effect of the outer rotor 6 against the flange 3'. The medium pressure level denotes a pressure level between the pressure level of the suction area 8 and the pressure level of the pressure area 9.

[0030] The shaft 4' is formed as a hollow shaft with an axial through-opening 4a' as a separate element and as a device for pressure equalization between the motor space 2a and the suction area 8. The liquid entering the motor space 2a, for example the gear lubricant, flows as a leakage flow from the motor space 2a through the axial through-opening 4a' formed in the shaft 4' again into the suction area 8. A throttle device can be formed in the axial through-opening 4a' to minimize the leakage of the liquid. The leakage flow of the liquid through the motor space 2a can dissipate, for example, waste heat generated in the device 1', in particular the electric motor 20. The leakage flow can also be used to lubricate the bearings of the shaft 4'.

[0031] Figures 2a and 2b show a liquid transfer device 1, in particular a gerotor pump, in side and front views, in which an external rotor 6 is arranged on a pile-shaped bearing member 4 formed integrally with a flange 3. Figure 2c shows a perspective view of the device 1 according to figures 2a and 2b, with a flange 3 formed integrally with a bearing member 4 for accommodating the external rotor 6. Identical components of the devices (1, 1') are provided with identical reference symbols. For an explanation of the function of similar components, reference is also made to the explanation for the device 1' according to figures 1a and 1b.

[0032] The essential difference between the device 1' according to figures 1a and 1b of the prior art and the device 1 according to figures 2a and 2b is that the shaft 4' is formed as a bearing member 4 coupled to a flange 3. In comparison with the rotatable shaft 4' of the device 1', the bearing member 4 is rigid and immovable and therefore corresponds to a fixed shaft.

[0033] Thus, the rotor 21 of the electric motor 20 of the device 1 together with the external rotor 6 of the displacement mechanism are mounted for rotation about a longitudinal axis 5 on a pile-shaped bearing member 4 oriented in the direction of the longitudinal axis 5. Like the eccentric 3a, the solid, non-rotating bearing member 4 is integrally formed with the flange 3 as part of it. The rotor 21 of the electric motor 20 and the external rotor 6 of the displacement mechanism are mounted directly on the flange 3, which can be considered as a component of the housing 2. The cylindrical bearing member 4 has a constant outer diameter over its length in the longitudinal direction 5.

[0034] The integral formation of the flange 3 with the eccentric part 3a and with the pile-shaped bearing element 4 protruding from the free end face of the eccentric part 3a facing towards the housing 2 means that in the area of ​​the flange 3' in the axially facing receiving opening 3b' there is no need to mount a rotating shaft 4 corresponding to the device 1' of Fig. 1a and Fig. 1b. As a result, the flange 3 is formed without a receiving opening, which weakens the wall of the flange 3. Instead of a receiving opening formed in the area of ​​the flange 3 formed as the eccentric part 3a for receiving a rotating shaft, the bearing element 4, which is formed integrally with the flange 3 and is rigid, has on its lateral surface a first bearing surface 10 for guiding the rotor 21 of the electric motor 20 together with the external rotor 6. On the outside of the eccentric part 3a a second bearing surface 11 is formed for guiding the internal rotor 7 driven by the external rotor 6 of the displacement mechanism.

[0035] The device 1 has a flattened area 12 of the cylindrical eccentric part 3a as a device for pressure equalization. The flattened area 12, which is provided on the outer lateral surface of the cylindrical shape with a circular cross section, extends axially over the entire length of the eccentric part 3a and therefore from the free end face facing towards the housing 2 to the second end face of the eccentric part 3a. At the second end face, the eccentric part 3a is integrated into the area of ​​the flange 3 closing the housing 2. By means of the flattened area 12 of the eccentric part 3a, a flow passage is formed between the eccentric part 3a and the inside of the internal rotor 7. In the transition area leading from the eccentric part 3a to the area of ​​the flange 3 closing the housing 2, a radially extending groove 13 is formed in the flange 3. The groove 13 connects the flow passage formed between the eccentric part 3a and the inner side of the internal rotor 7 to the suction area 8 of the device 1.

[0036] Via the flattened area 12 of the eccentric part 3a, via the intermediate space formed between the eccentric part 3a and the inside of the inner rotor 7 and the groove 13 fluidly connected thereto, and via the bearing play between the rotor 21 and the first bearing surface 10, a flow passage is ensured for the leakage flow of liquid from the motor space 2a to the suction area 8. The throttling function is provided by the bearing clearance between the rotor 21 and the first bearing surface 10.

[0037] Due to the integration of the shaft as bearing member 4 in the flange 3 and thus the omission of a receiving opening for supporting a rotatable shaft in the flange, the outer diameter of the eccentric part 3a as bearing diameter of the internal rotor 7 of the device 1 is reduced compared to the prior art device 1' according to figures 1a and 1b, the wall thickness of the internal rotor 7 remains the same and / or the eccentricity of the device 1, in particular the internal rotor 7, is increased. Thus, an expansion of the conveying volume is possible, while the installation space of the device 1, in particular the outer diameter and the longitudinal extent, remains the same compared to the prior art device 1'. Alternatively, it is also possible to reduce the installation space of the device 1, while the conveying volume remains the same.

[0038] Figures 3a and 3b show in side and front section a device (1-1) for transferring liquids in a first embodiment of a gerotor pump in which an external rotor 6 is arranged on a pile-shaped bearing element (4-1) formed integrally with a flange (3-1) with an axial through opening 4a as a device for pressure equalization between the suction area 8 and the motor space 2a. Figure 3c shows in a perspective view the flange (3-1) of the device (1-1) according to Figures 3a and 3b, in which the flange (3-1) is formed integrally with a bearing element (4-1) for receiving the external rotor 6. Identical components of the device (1, 1-1) according to Figures 2a to 2c are provided with the same reference symbols. For a functional description of the same components, reference is also made to the description of the device 1 according to Figures 2a to 2c.

[0039] The fundamental difference between the device 1 according to Fig. 2a and Fig. 2b and the device (1-1) according to Fig. 3a and Fig. 3b lies in the formation of the flange (3, 3-1) and the bearing element (4, 4-1) with an axial through-opening 4a. The axially directed through-opening is formed coaxially with the longitudinal axis 5 as a device for pressure equalization between the motor space 2a and the suction area 8. The axial through-opening 4a thus constitutes a fluid connection between the motor space 2a of the device (1-1) and the suction area 8, such that the liquid flowing inside the motor space 2a, in particular the gear lubricant, returns as a leakage flow from the motor space 2a through the axial through-opening 4a to the suction area 8. The axial through-opening 4a, which extends from the first free end face in the axial direction to the interior of the bearing element (4-1), the bearing element (4-1) and the eccentric part (3a-1) of the flange (3-1), is formed with a liquid throttling device in order to minimize leakage. The axial through-opening 4a opens into the interior of the motor space 2a from the region of the first end face of the bearing element (4-1). The intermediate space formed between the eccentric part (3a-1) and the inside of the inner rotor 7 by the flattened area 12 of the eccentric part (3a-1) and the grooves 13 fluidly connected thereto are used for lubrication, cooling or pressure relief of the bearing.

[0040] In order to further increase the conveying volume while keeping the installation space of the device the same, or to keep the conveying volume of the device the same while reducing the installation space of the device, it is necessary to reduce the diameter of the pile-shaped bearing element. Figures 4a and 4b show a second embodiment of a gerotor pump in side and front view, in which the external rotor 6 is arranged on a pile-shaped bearing element (4-2) formed integrally with a flange (3-2) having a flattened area 14 as a device for pressure equalization between the suction area 8 and the motor space 2a. Figure 4c shows a perspective view of the flange (3-2) formed integrally with the bearing element 4 for accommodating the external rotor 6 of the device (1-2) according to Figures 4a and 4b. Identical components of the devices (1, 1-1, 1-2) are provided with the same reference symbols. For the explanation of the function of similar components, reference is also made to the explanation of the device 1 according to Figures 2a and 2b.

[0041] The fundamental difference between the devices (1, 1-1, 1-2) is in the formation of the bearing members (4, 4-1, 4-2) and flanges (3, 3-1, 3-2) for the device for pressure equalization between the motor space 2a and the suction area 8. In the device (1-2) of Fig. 4a and Fig. 4b, as a device for pressure equalization, flattened areas (12, 14) are arranged on the cylindrical eccentric part (3a-2) and on the cylindrical bearing member (4-2), respectively. The flattened areas (12, 14) are provided on the outer lateral surfaces of cylinders with a circular cross section, respectively. In comparison with the device (1-1) of Fig. 3a and Fig. 3b, the bearing member (4-2) and the eccentric part (3a-2), respectively, are round rods, without axial openings and made of a hard material.

[0042] Analogously to the device (1, 1-1) of figures 2a-2c, 3a-3c, the first flattened area 12 extends axially over the entire length of the eccentric part (3a-2) and thus from the free end face facing towards the housing 2 to the second end face of the eccentric part (3a-2) which is integrated in the area of ​​the flange (3-2) closing the housing 2. Via the first flattened area 12 of the eccentric part (3a-2), a flow passage is formed between the eccentric part (3a-2) and the inside of the internal rotor 7.

[0043] In the transition area from the eccentric part (3a-2) to the area of ​​the flange (3-2) closing the housing 2, the flange (3-2) is formed with a radially extending groove 13. The groove 13 connects the flow passage formed between the eccentric part (3a-2) and the inner flank of the inner rotor 7 with the suction area 8 of the device (1-2).

[0044] In contrast to the device (1, 1-1) of Fig. 2a-c and Fig. 3a-c, the second flattened area 14 extends axially over the entire length of the bearing element (4-2), thus from the first free end face to the second end face of the bearing element (4-2). At the second end face, the bearing element (4-2) is connected to the eccentric part (3a-2), in particular to the free end face of the eccentric part (3a-2) facing towards the housing 2. Via the second flattened area 14 of the bearing element (4-2), a flow passage between the bearing element (4-2) and the outer rotor 6 or the inside of the rotor 21 of the electric motor 20 is ensured.

[0045] The fluidically connected intermediate spaces and grooves 13 formed between the bearing member (4-2) and the inner side of the outer rotor 6 or the rotor 21 of the electric motor 20 by the second flattened area 14 of the bearing member (4-2) and between the eccentric part (3a-2) and the inner side of the inner rotor 6 by the first flattened area 12 of the eccentric part (3a-2) ensure a flow passage for leakage flow of liquid from the motor space 2a to the suction area 8. By adjusting the depth of the grooves 13 or of the flattened areas (12, 14) radially, a throttling function is provided.

[0046] By forming the flattened areas (12, 14) of the device (1-2) instead of the through opening 4a of the device (1-1), the outer diameter of the eccentric part (3a-2) and therefore the inner diameter of the internal rotor 7 is less restricted than in the device (1-1) with the through opening 4a according to figures 3a to 3c. In particular, the outer diameter of the eccentric part (3a-2) of the device (1-2) can have a lower value than in the device (1-1), so that the entire flange (3-2), especially in the region of the bearing member (4-2), can be formed to have a smaller radial extent than the flange (3-1) of the device (1-1).

[0047] 5a and 5b show a liquid transfer device (1-3) in a side view and a front view of a third embodiment of a gerotor pump with two mutually opposed and axially offset sections of the second flattened area 14 of the device for pressure equalization between the suction area 8 and the motor space 2a, with an external rotor 6 arranged on a pile-shaped bearing member (4-3) formed integrally with the flange (3-3). FIG. 5c shows a perspective view of the flange (3-3) of the device (1-3) according to 5a and 5b, with a flange (3-3) formed integrally with a bearing member (4-3) for accommodating the external rotor 6. The same components of the devices (1, 1-1, 1-2, 1-3) are again provided with the same reference signs. To explain the function of the similar components, reference is also made to the description of the device 1 according to 2a to 2c.

[0048] The fundamental difference between the devices (1-2, 1-3) is that for the device for pressure equalization, a bearing element (4-2, 4-3) and a flange (3-2, 3-3) are formed between the motor space (2a) and the suction area (8). Compared to the flange 3-2 of the device (1-2) according to Fig. 4a and Fig. 4b, the flange (3-3) of the device (1-3) according to Fig. 5a and Fig. 5b includes, as a pressure equalization device, two sections (14-1, 14-2) of the second flattened area 14 of the cylindrical bearing element (4-3). The two sections (14-1, 14-2) of the second flattened area 14 are arranged radially opposite each other and axially offset from each other on the outer lateral surface of a cylindrical shape, respectively, having a circular cross section. The bearing element (4-3) is alternatively flat.

[0049] The alternative formation of the first section (14-1) and the second section (14-2) of the second flattened area 14 on the bearing member (4-3) results in a stable arrangement of the rotor 21 of the electric motor 20 or the outer rotor 6 on the bearing member (4-3). This result serves in particular to prevent potential tilting of the outer rotor 6 relative to the bearing member (4-3) and the longitudinal axis 5. The mutually opposing sections (14-1, 14-2) of the second flattened area 14 are designed in such a way that the forces resulting from the tilting of the outer rotor 6 are supported, the sections (14-1, 14-2) being provided on the opposite side of the tilting. This allows to reduce the tilting of the outer rotor 6 of the device (1-3) compared to the design of the device (1-2). [Explanation of symbols]

[0050] 1, 1-1, 1-2, 1-3, 1' device 2. Housing 2a Motor space 3, 3-1, 3-1, 3-2, 3-3, 3' flange 3a, 3a-1, 3a-2, 3a-3, 3a' eccentric part 3b' Receptor opening 4, 4-1, 4-2, 4-3 Bearing parts 4' Shaft 4a, 4a' Axial through opening 5 Vertical axis 6 External rotor 7 Internal Rotor 8 Suction Area 9 Pressure Areas 10 First bearing surface 11 Second bearing surface 12 first flattened area of ​​the second bearing surface (11) 13 Home 14 Second flattened area (14) of first bearing surface (10) 14-1 First section of the second planarization area (14) 14-2 Second section of the second flattening area (14) 20 Electric Motor 21 Rotor 21a Rotor Lamination

Claims

1. 1. A gerotor pump, comprising: A housing (2) having a flange (3, 3-1, 3-2, 3-3) enclosing a volume; an outer rotor (6) mounted for rotation about a longitudinal axis (5) and an inner rotor (7) of the displacement mechanism; and a rotor (21) of an electric drive unit formed integrally with said external rotor (6), said flanges (3, 3-1, 3-2, 3-3) being integrally formed with an eccentric portion (3a, 3a-1, 3a-2, 3a-3) for receiving said inner rotor (7) and with a conical bearing member (4, 4-1, 4-2, 4-3) extending in said direction of said longitudinal axis (5) for receiving said outer rotor (6); An apparatus (1, 1-1, 1-2, 1-3) for transporting liquid.

2. 2. The device (1, 1-1, 1-2, 1-3) according to claim 1, characterized in that said bearing member (4, 4-1, 4-2, 4-3) is at least substantially cylindrical and formed with a constant outer diameter in the direction of said longitudinal axis (5).

3. The device (1, 1-1, 1-2, 1-3) according to claim 1 or 2, characterized in that the bearing members (4, 4-1, 4-2, 4-3) are formed protruding from the free end faces of the eccentric portions (3a, 3a-1, 3a-2, 3a-3) facing in the direction of the housing (2).

4. The device (1, 1-1, 1-2, 1-3) according to claim 2 or 3, characterized in that the lateral surfaces of the bearing members (4, 4-1, 4-2, 4-3) comprise bearing surfaces (10) for guiding, together with the external rotor (6), the rotor (21) of the electric drive device.

5. The device (1, 1-1, 1-2, 1-3) according to any one of claims 2 to 4, characterized in that a bearing surface (11) for guiding the inner rotor (7) driven by the outer rotor (6) is formed on the outside of the eccentric portion (3a, 3a-1, 3a-2, 3a-3).

6. The device (1, 1-1, 1-2, 1-3) according to any one of claims 2 to 5, characterized in that the fluid connection of the device for pressure equalization is formed between an engine space (2a) as a volumetric area enclosed by the housing (2) having a flange (3, 3-1, 3-2, 3-3) and a suction area (8).

7. 7. The device (1, 1-1, 1-2, 1-3) according to claim 6, characterized in that said flange (3-1) is formed with an axial through opening (4a) at least in said area of ​​said bearing member (4-1) and said eccentric part (3a-1).

8. 8. The device (1, 1-1, 1-2, 1-3) according to claim 7, characterized in that the axial through opening (4a) is formed starting from a first free end face in the axial direction and extending inside the bearing member (401).

9. 9. The device (1, 1-1, 1-2, 1-3) according to claim 7 or 8, characterized in that the axial through opening (4a) is formed oriented coaxially with the longitudinal axis (5) of the device (1-1).

10. the flange (3, 3-1, 3-2, 3-3) includes a flattened region (12) in the region of the eccentric portion (3a, 3a-1, 3a-2, 3a-3); 7. The device (1, 1-1, 1-2, 1-3) according to claim 6, characterized in that said planarized area (12) is formed on an outer lateral surface.

11. the flanges (3-2, 3-3) include respective flattened areas (12, 14, 14-1, 14-2) in the area of ​​the cylindrical bearing member (4-2, 4-3) and in the area of ​​the eccentric portion (3a-2, 3a-3); 11. The device (1, 1-1, 1-2, 1-3) according to claim 10, characterized in that said planarized areas (12, 14, 14-1, 14-2) are formed on respective outer lateral surfaces.

12. 12. The device (1, 1-1, 1-2, 1-3) according to claim 10 or 11, characterized in that a first flattened area (12) is formed extending in the axial direction over the entire length of the eccentric portion (3a, 3a-1, 3a-2, 3a-3) from a first free end face to a second end face of the eccentric portion (3a, 3a-1, 3a-2, 3a-3).

13. The device (1, 1-1, 1-2, 1-3) according to claim 12, characterized in that the flange (3, 3-1, 3-1, 3-2, 3-3) has a radially extending groove (13), the groove (13) being formed extending between the first flattened area (12) and the suction area (8) of the device (1, 1-1, 1-2, 1-3).

14. The device (1, 1-1, 1-2, 1-3) according to any one of claims 11 to 13, characterized in that a second flattened area (14, 14-1, 14-2) is formed starting from a first free end face of the bearing member (4-2, 4-3) and extending in the axial direction to a second end face.

15. 15. The device (1, 1-1, 1-2, 1-3) according to claim 14, characterized in that the second flattened area (14) is formed extending continuously in the axial direction over the entire length of the bearing member (4-2).

16. The device (1, 1-1, 1-2, 1-3) according to claim 14, characterized in that the second flattened region (14) is composed of at least two sections (14-1, 14-2) each extending in the axial direction over a portion of the length of the bearing member (4-3).

17. 17. The device (1, 1-1, 1-2, 1-3) according to claim 16, characterized in that the at least two sections (14-1, 14-2) of the second flattened area (14) are arranged opposite each other in the radial direction on the bearing member (4-3) and offset from each other in the axial direction.

18. A motor vehicle using a device (1, 1-1, 1-2, 1-3) according to any one of claims 1 to 17 for transporting liquids within the vehicle, for lubricating and cooling gears with oil or liquid, or for cooling a battery or an electric engine.

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