Device for transporting a liquid

Abstract

A device for transporting a liquid, in particular a gerotor pump. The device has a housing with a flange which enclose a volume, an outer rotor mounted for rotation about a longitudinal axis and an inner rotor of a displacement mechanism, and a rotor of an electric drive. The rotor of the electric drive is formed integrally with the outer rotor. In addition, the flange is formed integrally with an eccenter for receiving the inner rotor and with a peg-shaped bearing element extending in the direction of the longitudinal axis for receiving the outer rotor.

Claims

1. A device for transporting a liquid comprising: a housing with a flange which enclose a volume, an outer rotor mounted for rotation about a longitudinal axis and an inner rotor of a displacement mechanism, and a rotor of an electric drive which is integrally formed with the outer rotor, wherein the flange is integrally formed with an eccenter for receiving the inner rotor and a pin-shaped bearing element extending in a direction of the longitudinal axis for receiving the outer rotor, wherein the bearing element is formed at least substantially cylinder-shaped with a constant outer diameter in the direction of the longitudinal axis, wherein a fluidic connection of a device for pressure equalization is formed between a motor space as a region of the volume enclosed by the housing with the flange and a suction region, wherein the flange has a flattened region in a region of the eccenter, wherein the flattened region is formed on an outer lateral surface, and wherein a first flattened region is formed extending in an axial direction over a full length of the eccenter, starting from a first, free end face to a second end face of the eccenter.

2. The device according to claim 1, wherein the bearing element is formed protruding from a free end face of the eccenter facing in a direction of the housing.

3. The device according to claim 2, wherein a lateral surface of the bearing element has a first bearing surface for guiding the rotor of the electric drive with the outer rotor.

4. The device according to claim 3, wherein a second bearing surface for guiding the inner rotor driven by the outer rotor is formed on an outside of the eccenter.

5. The device according to claim 1, wherein the flange is formed with an axial through opening at least in a region of the bearing element and of the eccenter.

6. The device according to claim 5, wherein the through opening is formed extending starting from the first, free end face in the axial direction into the bearing element.

7. The device according to claim 6, wherein the through opening is formed oriented coaxially with the longitudinal axis of the device.

8. The device according to claim 1, wherein the flange has a respective flattened region in a region of the bearing element and in the region of the eccenter, wherein the respective flattened region is formed on the outer lateral surface.

9. The device according to claim 1, wherein the flange has a groove running in a radial direction which is formed extending between the first flattened region and the suction region of the device.

10. A method of using the device for transporting the liquid according to claim 1 in a motor vehicle for lubricating and cooling a gear with an oil as the liquid or for cooling a battery or an electric engine.

11. A device for transporting a liquid comprising: a housing with a flange which enclose a volume, an outer rotor mounted for rotation about a longitudinal axis and an inner rotor of a displacement mechanism, and a rotor of an electric drive which is integrally formed with the outer rotor, wherein the flange is integrally formed with an eccenter for receiving the inner rotor and a pin-shaped bearing element extending in a direction of the longitudinal axis for receiving the outer rotor, wherein the bearing element is formed at least substantially cylinder-shaped with a constant outer diameter in the direction of the longitudinal axis, wherein a fluidic connection of a device for pressure equalization is formed between a motor space as a region of the volume enclosed by the housing with the flange and a suction region, wherein the flange has a respective flattened region in a region of the cylinder-shaped bearing element and in a region of the eccenter, wherein the respective flattened region is formed on an outer lateral surface, and wherein a second flattened region is formed extending in an axial direction, starting from a first, free end face to a second end face of the bearing element.

12. The device according to claim 11, wherein the second flattened region is formed extending in the axial direction continuously over a full length of the bearing element.

13. The device according to claim 11, wherein the second flattened region is formed from at least two sections extending in the axial direction respectively over a partial length of the bearing element.

14. The device according to claim 13, wherein the at least two sections of the second flattened region are formed arranged on the bearing element opposite to one another in the radial direction and offset from one another in the axial direction.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further details, features and advantages of embodiments of the invention can be found in the description of exemplary embodiments below with reference to the associated drawings. In the drawings:

(2) FIGS. 1A and 1B: show a gerotor pump with a housing closed by a flange, an outer rotor arranged on a rotatably mounted shaft, and an inner rotor, and a device for pressure equalization between a suction region and a motor space from the prior art, in a sectional diagram from the side and a sectional diagram from above,

(3) FIGS. 2A and 2B: show a gerotor pump with an arrangement of the outer rotor on a peg-shaped bearing element formed integrally with the flange, in a sectional diagram from the side and a sectional diagram from above,

(4) FIG. 2C: shows the flange, formed integrally with the bearing element for receiving the outer rotor, of the gerotor pump according to FIGS. 2A and 2B in a perspective view,

(5) FIGS. 3A and 3B: show a first embodiment of a gerotor pump with the arrangement of the outer rotor on the peg-shaped bearing element formed integrally with the flange, with an axial through opening as the device for pressure equalization between the suction region and the motor space, in a sectional diagram from the side and a sectional diagram from above,

(6) FIG. 3C: shows the flange of the gerotor pump according to FIGS. 3A and 3B in a perspective view,

(7) FIGS. 4A and 4B: show a second embodiment of a gerotor pump with the arrangement of the outer rotor on the peg-shaped bearing element formed integrally with the flange, with a flattened region as the device for pressure equalization between the suction region and the motor space, in a sectional diagram from the side and a sectional diagram from above,

(8) FIG. 4C: shows the flange of the gerotor pump according to FIGS. 4A and 4B in a perspective view,

(9) FIGS. 5A and 5B: show a third embodiment of a gerotor pump with the arrangement of the outer rotor on the peg-shaped bearing element formed integrally with the flange, with two mutually opposing and axially offset sections of a flattened region as the device for pressure equalization between the suction region and the motor space, in a sectional diagram from the side and a sectional diagram from above, and

(10) FIG. 5C: shows the flange of the gerotor pump according to FIGS. 5A and 5B in a perspective view.

DESCRIPTION OF AN EMBODIMENT

(11) FIGS. 1A and 1B show a device 1 for transporting a liquid, in particular a gerotor pump, from the prior art in a sectional diagram from the side and a sectional diagram from above. The device 1 is formed with a housing 2 closed by a flange 3, an outer rotor 6 arranged on a rotatably mounted shaft 4, and an inner rotor 7, and a device for pressure equalization between a motor space 2a and a suction region 8.

(12) The substantially hollow circular cylinder-shaped housing 2 has a first closed end face. A second end face formed distally from the first end face is closed by means of the flange 3. The motor space 2a constitutes a first part of the volume enclosed by the housing 2 in combination with the flange 3, 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.

(13) A rotor 21 of an electric motor 20 with rotor laminations 21a is arranged 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 together with the stator lamination stack in a plastic. The plastic, which is moulded using an injection-moulding method, for example, forms the housing 2. The stator and the rotor 21 of the electric motor 20 extend along a common longitudinal axis 5, which constitutes the rotational axis of the rotor 21. The stator is positioned on an outer side of the rotor 21 in the radial direction, enclosing the rotor. The flange 3 can likewise be formed from a plastic, preferably from the same plastic as the housing 2, or from a metal.

(14) The rotor laminations 21a together with permanent magnets (not shown) are overmoulded with a plastic such that the rotor 21 of the electric motor 20 is formed integrally with the outer rotor 6 of the displacement mechanism. Consequently, the plastic forms both the rotor 21 of the electric motor 20 and the outer rotor 6 of the displacement mechanism in such a way that the outer rotor 6 is driven directly by the rotor 21 of the electric motor 20.

(15) The rotor 21 of the electric motor 20 together with the outer rotor 6 of the displacement mechanism is connected to the shaft 4 mounted for rotation about the longitudinal axis 5. The shaft 4 is supported on the housing 2 on one side and on the flange 3 on the other side via a bearing in each case. The shaft 4 is mounted in the axial direction on the housing 2, in the radial and axial directions on the flange 3, and in the region of the flange 3 inside a receiving opening 3b facing in an axial direction. The receiving opening 3b is provided in a region of the flange 3 formed as an eccenter 3a. The eccenter 3a is formed integrally with the flange 3 as a part of the flange 3.

(16) The inner rotor 7, driven by the outer rotor 6, of the displacement mechanism is mounted on an outer side of the eccenter 3a independently of the outer rotor 6 so that the inner rotor 7 is arranged eccentrically to the shaft 4 and to the outer rotor 6. The liquid to be transported by the device 1 is guided into intermediate spaces provided between the inner rotor 7 and the outer rotor 6 from the suction region 8 as an inlet of the device 1 to a pressure region 9 as an outlet of the device 1. The liquid is brought by the device 1 from a low pressure at the inlet to a higher pressure at the outlet.

(17) Owing to an inflow of the liquid through a gap remaining between the outer rotor 6 and the flange 3 from the pressure region 9 into the motor space 2a of the device 1, liquid is applied to the motor space 2a at an intermediate pressure level. As a result of the intermediate pressure prevailing in the motor space 2a, the gap remaining between the outer rotor 6 and the flange 3 is reduced, and thus the sealing effect of the outer rotor 6 on the flange 3 is increased. The intermediate pressure level represents a pressure level between the pressure levels of the liquid in the suction region 8 and in the pressure region 9.

(18) The shaft 4 is formed as a separate element and as a hollow shaft with a through opening 4a pointing in the axial direction as a device for pressure equalization between the motor space 2a and the suction region 8. The liquid flowing into the motor space 2a, for example a lubricating oil of a gear, flows as a leakage flow from the motor space 2a through the through opening 4a formed in the shaft 4 back to the suction region 8. The through opening 4a can be formed with a throttle device for the liquid to minimize leakage.

(19) With the leakage flow of the liquid through the motor space 2a, waste heat generated in the device 1, in particular by the electric motor 20, can be dissipated, for example. The leakage flow can also be used to lubricate the bearing of the shaft 4.

(20) FIGS. 2A and 2B show a device 1 for transporting a liquid, in particular a gerotor pump, with an arrangement of the outer rotor 6 on a peg-shaped bearing element 4 formed integrally with the flange 3, in a sectional diagram from the side and a sectional diagram from above. FIG. 2C shows the flange 3, formed integrally with the bearing element 4 for receiving the outer rotor 6, of the device 1 according to FIGS. 2A and 2B in a perspective view.

(21) Like components of the devices 1, l are provided with the same reference signs. For the description of the functions of like components, reference is also made to the statements relating to the device 1 according to FIGS. 1A and 1B.

(22) An essential difference between the device 1 according to FIGS. 1A and 1B from the prior art and the device 1 according to FIGS. 2A and 2B lies in the formation of the shaft 4 as a bearing element 4 in conjunction with the flange 3, 3. In comparison with the rotatable shaft 4 of the device 1, the bearing element 4 corresponds to a rigid, immovable and thus fixed shaft.

(23) Therefore, the rotor 21 of the electric motor 20 of the device 1 together with the outer rotor 6 of the displacement mechanism is mounted for rotation about the longitudinal axis 5 on the peg-shaped bearing element 4 oriented in the direction of the longitudinal axis 5. Like the eccenter 3a, the rigid and thus non-rotational bearing element 4 is formed integrally with the flange 3 as a part of the flange 3. The rotor 21 of the electric motor 20 and the outer rotor 6 of the displacement mechanism are thus mounted directly on the flange 3, which can also be regarded as a component of the housing 2. The cylinder-shaped bearing element 4 has a constant outer diameter over the length in the direction of the longitudinal axis 5.

(24) The integral formation of the flange 3 with the eccenter 3a and the peg-shaped bearing element 4 protruding from a free end face of the eccenter 3a facing in the direction of the housing 2 means that it is no longer necessary to mount the rotatable shaft 4, corresponding to the device 1 from FIGS. 1A and 1B, in the region of the flange 3 inside the receiving opening 3b facing in the axial direction. Consequently, the flange 3 is formed without the receiving opening, which weakens the wall of the flange 3.

(25) Instead of the receiving opening in the region of the flange 3 formed as an eccenter 3a for receiving the rotatable shaft, the bearing element 4 which is formed integrally with the flange 3 and is thus rigid has, on the lateral surface, a first bearing surface 10 for guiding the rotor 21 of the electric motor 20 with the outer rotor 6. A second bearing surface 11 for guiding the inner rotor 7, driven by the outer rotor 6, of the displacement mechanism is formed on the outer side of the eccenter 3a.

(26) The device 1 has a flattened region 12 of the cylinder-shaped eccenter 3a as a device for pressure equalization. The flattened region 12, which is provided on the outer lateral surface of the cylinder with an otherwise circular cross section, extends in the axial direction over the full length of the eccenter 3a and thus from a free end face facing in the direction of the housing 2 to a second end face of the eccenter 3a. At the second end face, the eccenter 3a merges into the region of the flange 3 which closes the housing 2. With the flattened region 12 of the eccenter 3a, a flow path is formed between the eccenter 3a and the inner side of the inner rotor 7.

(27) In the region of the transition from the eccenter 3a to the region of the flange 3 closing the housing 2, the flange 3 is formed with a groove 13 running in the radial direction. The groove 13 connects the flow path formed between the eccenter 3a and the inner side of the inner rotor 7 to the suction region 8 of the device 1.

(28) With the intermediate space formed between the eccenter 3a and the inner side of the inner rotor 7 by the flattened region 12 of the eccenter 3a, the groove 13, and the bearing play between the rotor 21 and the first bearing surface 10, which are fluidically connected to one another, the flow path for the leakage flow of the liquid from the motor space 2a to the suction region 8 is ensured. The throttle function is provided via the bearing play between the rotor 21 and the first bearing surface 10.

(29) With the integration of the shaft as the bearing element 4 in the flange 3 and thus the omission of the receiving opening for supporting the rotatable shaft inside the flange, the outer diameter of the eccenter 3a as the bearing diameter of the inner rotor 7 of the device 1 is reduced in comparison with the device 1 from the prior art according to FIGS. 1A and 1B while the wall thickness of the inner rotor 7 remains the same, and/or the eccentricity of the device 1, in particular of the inner rotor 7, is increased.

(30) A larger transport volume is thus made possible while the installation space of the device 1, in particular the outer diameter and the extent in the direction of the longitudinal axis, remains the same in comparison with the device 1 from the prior art. Alternatively, the installation space of the device 1 can be reduced while the transport volume remains the same.

(31) FIGS. 3A and 3B show a device 1-1 for transporting a liquid as a first embodiment of a gerotor pump with the arrangement of the outer rotor 6 on the peg-shaped bearing element 4-1 formed integrally with the flange 3-1, with an axial through opening 4a as the device for pressure equalization between the suction region 8 and the motor space 2a, in a sectional diagram from the side and a sectional diagram from above. FIG. 3C shows the flange 3-1, formed integrally with the bearing element 4-1 for receiving the outer rotor 6, of the device 1-1 according to FIGS. 3A and 3B in a perspective view.

(32) Like components of the devices 1, 1-1 according to FIG. 2A to 2C are provided with the same reference signs. For the description of the functions of like components, reference is also made to the statements relating to the device 1 according to FIG. 2A to 2C.

(33) An essential difference between the device 1 according to FIGS. 2A and 2B and the device 1-1 according to FIGS. 3A and 3B lies in the formation of the bearing element 4, 4-1 and of the flange 3, 3-1 with a through opening 4a.

(34) The through opening 4a facing in the axial direction is formed coaxially with the longitudinal axis 5 as a device for pressure equalization between the motor space 2a and the suction region 8. The through opening 4a therefore constitutes a fluidic connection between the motor space 2a and the suction region 8 of the device 1-1, so that liquid flowing into the motor space 2a, in particular the lubricating oil of a gear, flows as a leakage flow from the motor space 2a through the through opening 4a back to the suction region 8. The through opening 4a, which extends from a first, free end face in the axial direction into the bearing element 4-1 and through the bearing element 4-1 and the eccenter 3a-1 of the flange 3-1, is formed with a throttle device for the liquid to minimize leakage. The through opening 4a opens into the motor space 2a in the region of the first end face of the bearing element 4-1. The intermediate space and groove 13, which are connected fluidically to one another and are formed between the eccenter 3a-1 and the inner side of the inner rotor 7 by the flattened region 12 of the eccenter 3a-1, are used for the lubrication, cooling or pressure relief of the bearing.

(35) To increase the transport volume further while keeping the installation space of the device the same, or to reduce the installation space further while keeping the transport volume of the device the same, the diameter of the peg-shaped bearing element should be reduced.

(36) FIGS. 4A and 4B show a device 1-2 for transporting a liquid as a second embodiment of a gerotor pump with the arrangement of the outer rotor 6 on the peg-shaped bearing element 4-2 formed integrally with the flange 3-2, with a flattened region 14 as a section of a device for pressure equalization between the suction region 8 and the motor space 2a, in a sectional diagram from the side and a sectional diagram from above. FIG. 4C shows the flange 3-2, formed integrally with the bearing element 4-2 for receiving the outer rotor 6, of the device 1-2 according to FIGS. 4A and 4B in a perspective view.

(37) Like components of the devices 1, 1-1, 1-2 are again provided with the same reference signs. For the description of the functions of like components, reference is also made to the statements relating to the device 1 according to FIG. 2A to 2C.

(38) An essential difference between the devices 1, 1-1, 1-2 lies in the formation of the bearing element 4, 4-1, 4-2 and of the flange 3, 3-1, 3-2 with regard to the device for pressure equalization between the motor space 2a and the suction region 8.

(39) The device 1-2 from FIGS. 4A and 4B has a respective flattened region 12, 14 on the cylinder-shaped bearing element 4-2 and on the cylinder-shaped eccenter 3a-2 as the device for pressure equalization. The flattened regions 12, 14 are each provided on the outer lateral surface of the cylinder with an otherwise circular cross section. In comparison with the device 1-1 of FIGS. 3A and 3B, the bearing element 4-2 and the eccenter 3a-2 are each formed as a round rod and thus from solid material without an axial through opening.

(40) As in the devices 1, 1-1 of FIGS. 2A to 2C and 3A to 3C, the first flattened region 12 extends in the axial direction over the full length of the eccenter 3a-2 and thus from the free end face facing in the direction of the housing 2 to the second end face of the eccenter 3a-2 at which the eccenter 3a-2 merges into the region of the flange 3-2 which closes the housing 2. With the first flattened region 12 of the eccenter 3a-2, a flow path is formed between the eccenter 3a-2 and the inner side of the inner rotor 7.

(41) In the region of the transition from the eccenter 3a-2 to the region of the flange 3-2 closing the housing 2, the flange 3-2 is formed with the groove 13 running in the radial direction, which connects the flow path formed between the eccenter 3a-2 and the inner side of the inner rotor 7 to the suction region 8 of the device 1-2.

(42) In contrast to the devices 1, 1-1 of FIGS. 2A to 2C and 3A to 3C, a second flattened region 14 extends in the axial direction over the full length of the bearing element 4-2 and thus from the first, free end face to a second end face of the bearing element 4-2. At the second end face, the bearing element 4-2 is connected to the eccenter 3a-2, in particular to a free end face of the eccenter 3a-2 facing in the direction of the housing 2. With the second flattened region 14 of the bearing element 4-2, a flow path is ensured between the bearing element 4-2 and the inner side of the outer rotor 6 or the rotor 21 of the electric motor 20.

(43) With the intermediate spaces and the groove 13 which are connected fluidically to one another and formed between the bearing element 4-2 and the inner side of the outer rotor 6 or the rotor 21 of the electric motor 20 by the second flattened region 14 of the bearing element 4-2 and between the eccenter 3a-2 and the inner side of the inner rotor 7 by the first flattened region 12 of the eccenter 3a-2, the flow path is ensured for the leakage flow of the liquid from the motor space 2a to the suction region 8.

(44) The throttle function is provided by adapting the depth of the flattened regions 12, 14 in the radial direction or of the groove 13. With the formation of the flattened regions 12, 14 of the device 1-2 instead of the through opening 4a of the device 1-1, the outer diameter of the eccenter 3a-2 and thus the inner diameter of the inner rotor 7 is less limited than in the device 1-1 with the through opening 4a according to FIG. 3A to 3C. Since in particular the outer diameter of the eccenter 3a-2 of the device 1-2 can have lower values than the device 1-1, the entire flange 3-2, specifically in the region of the bearing element 4-2, can also be formed with a smaller radial extent than the flange 3-1 of the device 1-1.

(45) FIGS. 5A and 5B show a device 1-3 for transporting a liquid as a third embodiment of a gerotor pump with the arrangement of the outer rotor 6 on the peg-shaped bearing element 4-3 formed integrally with the flange 3-3, with two mutually opposing and axially offset sections of the second flattened region 14 of a device for pressure equalization between the suction region 8 and the motor space 2a, in a sectional diagram from the side and a sectional diagram from above. FIG. 5C shows the flange 3-3, formed integrally with the bearing element 4-3 for receiving the outer rotor 6, of the device 1-3 according to FIGS. 5A and 5B in a perspective view.

(46) Like components of the devices 1, 1-1, 1-2, 1-3 are again provided with the same reference signs. For the description of the functions of like components, reference is also made to the statements relating to the device 1 according to FIG. 2A to 2C.

(47) An essential difference between the devices 1-2, 1-3 lies in the formation of the bearing element 4-2, 4-3 and thus of the flange 3-2, 3-3 with the eccenter 3a-2, 3a-3 with regard to the device for pressure equalization between the motor space 2a and the suction region 8.

(48) In comparison with the flange 3-2 of the device 1-2 according to FIGS. 4A and 4B, the flange 3-3 of the device 1-3 according to FIGS. 5A and 5B has two sections 14-1, 14-2 of the flattened second region 14 of the cylinder-shaped bearing element 4-3 as the device for pressure equalization. The two sections 14-1, 14-2 of the second flattened region 14 are each arranged on the outer lateral surface of the cylinder with an otherwise circular cross section, opposing one another in the radial direction and offset from one another in the axial direction. The bearing element 4-3 is alternately flattened.

(49) The alternate formation of the first section 14-1 and of the second section 14-2 of the second flattened region 14 on the bearing element 4-3 results in a stable arrangement of the outer rotor 6 or the rotor 21 of the electric motor 20 on the bearing element 4-3. This helps in particular to prevent possible tilting of the outer rotor 6 relative to the bearing element 4-3 and the longitudinal axis 5. The mutually opposing sections 14-1, 14-2 of the second flattened region 14 are designed such that the forces resulting from tilting of the outer rotor 6 are supported, and a section 14-1, 14-2 is provided on the respective opposite side of the tilting, which reduces tilting of the outer rotor 6 of the device 1-3 in comparison with the design of the device 1-2.

LIST OF REFERENCE NUMERALS

(50) 1, 1-1, 1-2, 1-3, 1 Device 2 Housing 2a Motor space 3, 3-1, 3-2, 3-3, 3 Flange 3a, 3a-1, 3a-2, 3a-3, 3a Eccenter 3b Receiving opening 4, 4-1, 4-2, 4-3 Bearing element 4 Shaft 4a, 4a Axial through opening 5 Longitudinal axis 6 Outer rotor 7 Inner rotor 8 Suction region 9 Pressure region 10 First bearing surface 11 Second bearing surface 12 First flattened region of second bearing surface 11 13 Groove 14 Second flattened region of first bearing surface 10 14-1 First section of second flattened region 14 14-2 Second section of second flattened region 14 20 Electric motor 21 Rotor 21a Rotor laminations