Pump with multiple gerotors, as well as hybrid module with the same

Abstract

Pump with multiple gerotors (102), comprising: a shaft (104, 204) rotatable about an axis; a first gerotor pump (108, 208) comprising a first inner gerotor (116, 216) rotatably mounted on the shaft (104, 204); a second gerotor pump (110, 210) comprising a second inner gerotor (118, 218) axially offset from the first inner gerotor (116, 216) and non-rotatably mounted on the shaft (104, 204); a housing (112, 212) comprising: an inlet channel (120, 220) of the first gerotor pump (108, 208) and an outlet channel (124, 224) of the first gerotor pump (108, 208); an inlet channel (122, 222) of the second gerotor pump (110, 210) and an outlet channel (126, 226) of the second gerotor pump (110, 210); and a reservoir (114, 214), wherein the outlet channel (124, 224) of the first gerotor pump (108, 208) and the inlet channel (122, 222) of the second gerotor pump (110, 210) are in fluid communication with the reservoir (114, 214), characterized in that the pump further comprises an electric pump motor (128, 228) for rotating the shaft (104, 204), wherein the first gerotor pump (108, 208) is a scavenging pump for transporting oil from an outlet (130, 230) of a hybrid module (132, 232) to the reservoir (114, 214); and the second gerotor pump (110, 210) is a cooling circuit pump for transporting the oil from the reservoir (114, 214) to a cooling circuit (134, 234) of the hybrid module (132, 232).

Description

TECHNICAL FIELDThe present disclosure relates generally to gerotor pumps, also known as ring gear pumps or Eaton pumps, and more specifically to a hybrid module having a multi-gerotor pump.BACKGROUNDFrom U.S. Pat. No. 6,679,692 B1 a pump is known which is readable on the preamble of claim 1. The same applies to DE 10 2005 006 810 A1. US 2012 / 0 258 838 A1 discloses a hybrid module having a mechanical coolant pump. US 2007 / 0 062 183 A1 discloses a power steering system with a gerotor pump. Furthermore, U.S. Pat. No. 2016 / 0 223 070 A1 discloses a hybrid vehicle with a coolant pump.The object of the present invention is to improve functionally said pump and a hybrid module comprising the pump.According to the invention, this object is achieved by a pump according to claim 1 and a hybrid module according to claim 9.SUMMARYExample embodiments broadly include a multi-gerotor pump including a shaft rotatable about an axis, a first gerotor pump, a second gerotor pump, a housing, and a reservoir. The first gerotor pump includes a first inner gerotor rotationally fixedly coupled to the shaft, and the second gerotor pump includes a second inner gerotor axially offset from the first inner gerotor and rotationally fixedly coupled to the shaft. The housing has an inlet channel of the first gerotor pump and an outlet channel of the first gerotor pump, and an inlet channel of the second gerotor pump and an outlet channel of the second gerotor pump. The outlet channel of the first gerotor pump and the inlet channel of the second gerotor pump are in fluid communication with the reservoir.In some example embodiments, the multi-gerotor pump also includes an electric pump motor for rotating the shaft. In an exemplary embodiment, the first gerotor pump also includes a first outer gerotor, the electric pump motor is arranged to rotate the first outer gerotor, and the first outer gerotor is arranged to rotate the first inner gerotor to rotate the shaft.In some example embodiments, the first gerotor pump is a scavenge pump for transporting oil from an outlet of a hybrid module to the reservoir, and the second gerotor pump is a cooling circuit pump for transporting the oil from the reservoir to a cooling circuit of the hybrid module. In a preferred embodiment, the wash pump has a higher pump capacity than the cooling circuit pump. In a preferred embodiment, the cooling circuit comprises an oil cooler.In a preferred embodiment, the inlet channel of the first gerotor pump and the outlet channel of the first gerotor pump are at least partially axially disposed between the first gerotor pump and the reservoir. In a preferred embodiment, the inlet channel of the second gerotor pump and the outlet channel of the second gerotor pump are at least partially axially disposed between the first gerotor pump and the reservoir. In some example embodiments, the shaft extends axially into the reservoir. In an exemplary embodiment, the reservoir has an axial width and the second gerotor pump is disposed within the axial width of the reservoir.Other example embodiments, in a broad sense, include a hybrid module including a module housing, an electric machine including a stator fixed to the housing and a rotatable rotor, and the multi-gerotor pump arranged to circulate a cooling fluid through the module housing. In an exemplary embodiment, the module housing has an outlet and a cooling circuit, the first gerotor pump is a scavenge pump for transporting the cooling fluid from the outlet to the reservoir, and the second gerotor pump is a cooling circuit pump for transporting the cooling fluid from the reservoir to the cooling circuit. In an exemplary embodiment, the outlet is disposed at a bottom of the module housing when the hybrid module is installed in a vehicle. In an exemplary embodiment, the outlet is arranged such that a cooling fluid level in the housing is lower than a bottom of the rotatable rotor. In an exemplary embodiment, the reservoir is disposed on an axial side of the module housing when the hybrid module is installed in a vehicle. In an exemplary embodiment, the cooling circuit includes a spray opening in the module housing that faces a top of the stator when the hybrid module is installed in a vehicle. In a preferred embodiment, the cooling circuit has a cooling fluid cooler.BRIEF DESCRIPTION OF THE DRAWINGSFIG. 1 illustrates a schematic view of a fluid circuit for a multi-gerotor pump, according to an example embodiment. FIG. 2 illustrates a cross-sectional view of a hybrid module showing a purge fluid of the multi-gerotor pump, according to an example embodiment. FIG. 3 illustrates a cross-sectional view of the hybrid module of FIG. 2 showing a portion of the cooling circuit.DETAILED DESCRIPTIONEmbodiments of the present disclosure are described herein. It should be understood that like reference numerals appearing in different drawing views designate identical or functionally similar structural elements. It is also to be understood that the disclosed embodiments are merely examples and other embodiments may take various and alternative forms. The figures are not necessarily to scale; some features could be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the embodiments. As those skilled in the art will understand, various features illustrated and described with reference to one of the figures may be combined with features illustrated in one or more other figures to produce embodiments that are not expressly illustrated or described. The illustrated combinations of features provide representative embodiments for typical applications. However, various combinations and modifications of the features consistent with the teachings of this disclosure could be desired for particular applications or implementations.The terminology used herein is for describing particular aspects only and is not intended to limit the scope of the present disclosure. Unless otherwise defined, all technical and scientific terms used herein are accorded the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains. Although any methods, devices, or materials similar or equivalent to those described herein may be used in the application or testing of the disclosure, the following example methods, devices, and materials will now be described.The following description is made with reference to FIG. 1, FIG. 1 illustrates a schematic view of a fluid circuit 100 for a multi-gerotor pump 102 according to an example embodiment. The multi-gerotor pump 102 includes a shaft 104 rotatable about the axis 106, the gerotor pumps 108 and 110, the housing 112, and the reservoir 114. The gerotor pump 108 includes an inner gerotor 116 rotationally fixed to the shaft, and the gerotor pump 110 includes an inner gerotor 118 axially offset from the inner gerotor 116 and rotationally fixed to the shaft. The housing includes inlet channels 120 and 122, and outlet channels 124 and 126. As shown in the figure, the outlet channel 124 and the inlet channel 122 are in fluid communication with the reservoir. The multi-gerotor pump 102 also includes an electric pump motor 128 for rotating the shaft.In the exemplary embodiment shown in FIG. 1, the gerotor pump 108 is a scavenge pump for transporting oil from the outlet 130 of the hybrid module 132 to the reservoir, and the gerotor pump 110 is a cooling circuit pump for transporting the oil from the reservoir to the cooling circuit 134 of the hybrid module. In this case, the wash pump has a higher pump capacity than the cooling circuit pump, with the result that the storage container always contains oil available for the cooling circuit pump. As shown in FIG. 1, the cooling circuit 134 includes an oil cooler 136. The oil cooler 136 may be a liquid-liquid cooler that uses coolant from another circuit (e.g., engine coolant entering and exiting through the openings 138 and 140) to cool the oil.The following description is made with reference to FIGS. 2 to 3, FIG. 2 illustrates a cross-sectional view of the hybrid module 232 showing a scavenging fluid of the multi-gerotor pump according to an exemplary embodiment. FIG. 3 illustrates a cross-sectional view of the hybrid module of FIG. 2 showing a portion of the cooling circuit 234. FIGS. 2 and 3 are received by various circumferentially offset portions of the hybrid module 232. The multi-gerotor pump 202 includes a shaft 204 rotatable about the axis 206, the gerotor pumps 208 and 210, the housing 212, and the reservoir 214. The gerotor pump 208 includes an inner gerotor 216 rotationally fixed to the shaft, and the gerotor pump 210 includes an inner gerotor 218 axially offset from the inner gerotor 216 and rotationally fixed to the shaft. The housing includes inlet channels 220 and 222 and outlet channels 224 and 226. As shown in the figure, the outlet channel 224 and the inlet channel 222 are in fluid communication with the reservoir.The multi-gerotor pump 202 also includes an electric pump motor 228 for rotating the shaft. The gerotor pump 208 includes an outer gerotor 229, and an electric pump motor 228 is arranged to rotate the first outer gerotor. The outer gerotor 229 is arranged to rotate the inner gerotor 216 to rotate the shaft 204.In the exemplary embodiment shown in FIG. 2, the gerotor pump 208 is a scavenge pump for transporting oil from the outlet 230 of the hybrid module 200 to the reservoir, and as shown in FIG. 3, the gerotor pump 210 is a cooling circuit pump for transporting the oil from the reservoir to the cooling circuit 234 of the hybrid module. In this case, the wash pump has a higher pump capacity than the cooling circuit pump, with the result that the storage container always contains oil available for the cooling circuit pump. The cooling circuit 234 may include a liquid-liquid oil cooler (not shown) that uses coolant from another circuit (e.g., engine coolant) to cool the oil.As shown in FIG. 2, the gerotor pump inlet port 220 and the gerotor pump outlet port 224 are both partially axially disposed between the gerotor pump 208 and the reservoir. Similarly, as shown in FIG. 3, the gerotor pump inlet channel 222 and the gerotor pump outlet channel 226 are partially axially disposed between the gerotor pump 208 and the reservoir. The shaft 204 extends into the reservoir and the gerotor pump 210 is disposed within the axial width 242 of the reservoir 214.The hybrid module 232 is disposed on the module housing 244 and an input damper 246, for example, for connection to an internal combustion engine of a vehicle (not shown). The module 232 includes an electric machine 248 having a stator 250 fixed to the housing and a rotatable rotor 252. The hybrid module also includes a multi-gerotor pump 202 arranged to circulate a cooling fluid through the module housing. The module housing 244 includes an outlet 230 and a cooling circuit 234. As described above, the gerotor pump 208 is a scavenge pump for transporting the cooling fluid from the outlet to the reservoir, and the gerotor pump 210 is a cooling circuit pump for transporting the cooling fluid from the reservoir to the cooling circuit. For example, as shown in FIG. 2, when the hybrid module is installed in a vehicle, the outlet is disposed on a bottom surface of the module housing such that the cooling fluid level 254 in the housing is lower than the rotatable rotor bottom surface 256. As shown in FIGS. 2 to 3, the reservoir tank is disposed on an axial side of the module case when the hybrid module is installed in a vehicle. The cooling circuit 234 includes a spray opening 258 in the module housing that faces a top of the stator when the hybrid module is installed in a vehicle. As discussed above, the cooling circuit may include a cooling fluid cooler (not shown in FIGS. 2-3 ). Hybrid module 132 in FIG. 1 includes elements similar to elements 2XX of module 232 labeled 1XX. For example, the stator 150 in FIG. 1 is comparable to the stator 250 in FIGS. 2 to 3. Coolant from spray orifice 158 / 258 flows through stator 150 / 250 and rotatable rotor 152 / 252 before collecting in housing sump 160 / 260 and exiting through outlet orifice 130 / 230. The reservoir maintains sufficient cooling fluid capacity with a minimum housing sump, thereby enabling more compact radial dimensions of the hybrid module.While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms encompassed by the claims. The words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the disclosure. As described above, the features of various embodiments may be combined to form further embodiments of the disclosure that may not be expressly described or illustrated. While various embodiments could have been described as being advantageous or preferred over other embodiments or implementations of the prior art with respect to one or more desired characteristics, those skilled in the art recognize that one or more features or characteristics can be compromised to achieve desired overall system attributes, which depend on the particular application and implementation. These attributes may include, but are not limited to, cost, strength, durability, life cycle cost, marketability, appearance, packaging, size, utility, weight, microencapsulated, assembly-friendliness, etc. Thus, to the extent that embodiments are described as less desirable than other embodiments or implementations of the prior art with respect to one or more characteristics, these embodiments are not outside the scope of the disclosure and may be desirable for particular applications.

Claims

A multi-gerotor pump (102) comprising: a shaft (104, 204) rotatable about an axis; a first gerotor pump (108, 208) comprising a first inner gerotor (116, 216) rotationally fixed to the shaft (104, 204); a second gerotor pump (110, 210) comprising a second inner gerotor (118, 218) axially offset from the first inner gerotor (116, 216) rotationally fixed to the shaft (104, 204); a housing (112, 212) comprising: an inlet channel (120, 220) of the first gerotor pump (108, 208) and an outlet channel (124, 224) of the first gerotor pump (108, 208); an inlet channel (122, 222) of the second gerotor pump (110, 210); and an outlet channel (126, 226) of the second gerotor pump (110, 210); and a reservoir (114, 214), wherein the outlet channel (124, 224) of the first gerotor pump (108, 208) and the inlet channel (122, 222) of the second gerotor pump (110, 210) are in fluid communication with the reservoir (114, 214), characterized in that the pump further comprises an electric pump motor (128, 228) for rotating the shaft (104, 204), wherein the first gerotor pump (108, 208) is a scavenge pump for transporting oil from an outlet (130, 230) of a hybrid module (132, 232) to the reservoir (114, 214); and the second gerotor pump (110, 210) is a cooling circuit pump for transporting the oil from the reservoir (114, 214) to a cooling circuit (134, 234) of the hybrid module (132, 232).The multi-gerotor pump (102) of claim 1, wherein the first gerotor pump (108, 208) further comprises a first outer gerotor; the electric pump motor (128, 228) is arranged to rotate the first outer gerotor; and the first outer gerotor is arranged to rotate the first inner gerotor (116, 216) to rotate the shaft (104, 204).The multi-gerotor pump (102) of claim 1 or 2, wherein the scavenge pump has a higher pumping capacity than the cooling circuit pump.The multi-gerotor pump (102) of any of claims 1 to 3, wherein the cooling circuit (134, 234) comprises an oil cooler (136).The multi-gerotor pump (102) of any of claims 1 to 4, wherein the inlet channel (120, 220) of the first gerotor pump (108, 208) and the outlet channel (124, 224) of the first gerotor pump (108, 208) are at least partially axially disposed between the first gerotor pump (108, 208) and the reservoir (114, 214).The multi-gerotor pump (102) of any of claims 1 to 5, wherein the inlet channel (122, 222) of the second gerotor pump (110, 210) and the outlet channel (126, 226) of the second gerotor pump (110, 210) are at least partially axially disposed between the first gerotor pump (108, 208) and the reservoir (114, 214).The multi-gerotor pump (102) of any of claims 1 to 6, wherein the shaft (104, 204) extends axially into the reservoir (114, 214).The multi-gerotor pump (102) of any of claims 1 to 7, wherein the reservoir (114, 214) comprises an axial width; and the second gerotor pump (110, 210) is disposed within the axial width of the reservoir.A hybrid module (132, 232) comprising: a module housing (244); an electric machine (248) comprising a stator (150, 250) secured to the housing (112, 212) and a rotatable rotor (152, 252); and the multi-gerotor pump (102) of any of claims 1 to 8 arranged to circulate a cooling fluid through the module housing (244).The hybrid module (132, 232) of claim 9, wherein the module housing (244) comprises an outlet (130, 230) and a cooling circuit (134, 234); the first gerotor pump (108, 208) is a scavenge pump for transporting the cooling fluid from the outlet (130, 230) to the reservoir (114, 214); and the second gerotor pump (110, 210) is a cooling circuit pump for transporting the cooling fluid from the reservoir (114, 214) to the cooling circuit (134, 234).The hybrid module (132, 232) of claim 10, wherein the outlet (130, 230) is disposed at a bottom of the module housing (244) when the hybrid module (132, 232) is installed in a vehicle.The hybrid module (132, 232) of claim 10 or 11, wherein the outlet (130, 230) is arranged such that a cooling fluid level in the housing (112, 212) is lower than a bottom (256) of the rotatable rotor (152, 252).The hybrid module (132, 232) of any of claims 9 to 12, wherein the reservoir (114, 214) is disposed on an axial side of the module housing (244) when the hybrid module (132, 232) is installed in a vehicle.The hybrid module (132, 232) of any of claims 9 to 13, wherein the cooling circuit (134, 234) comprises a spray orifice (158, 258) in the module housing (244) that faces a top of the stator (150, 250) when the hybrid module (132, 232) is installed in a vehicle.The hybrid module (132, 232) of any of claims 9 to 14, wherein the cooling circuit (134, 234) comprises a cooling fluid cooler.

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