SPLIT OUTPUT PORT FOR PUMP WITH INTERNAL TEMPERATURE MEASUREMENT DEVICE

Abstract

A pump system includes: a housing with a pump and an electric motor therein; a pump inlet with a pump inlet port; a pump outlet with a pump outlet port; a drive shaft rotatably driven by the electric motor, for driving the pump to pressurize fluid received through a main path of the pump from the pump inlet for output from an outlet path to the pump outlet; and a controller having a sensor. A portion of the pressurized fluid is directed to an auxiliary circuit for temperature measurement to provide an internal temperature check point of fluid within the system. The sensor is exposed to the auxiliary path, with or without use of a heat sink. Fluid is redirected to a return path for motor cooling and then a secondary path through the housing to return to the outlet path or the pump inlet.

Description

CROSS REFERENCE TO RELATED APPLICATION(S)

This disclosure claims priority to U.S. Provisional Patent Application No. 63/435,715, filed on Dec. 28, 2022, all contents of which are hereby incorporated by reference in their entirety.

BACKGROUND

Field

The present disclosure is generally related to a pump system including a pump and a motor, that has a split output port for directing a portion of fluid/lubricant from an outlet path to a temperature sensor, for control thereof.

Description of Related Art

The temperature of oil or fluid in pumps is generally checked to maintain safe operation of the pumps. U.S. Publication Nos. 2019/0003477 and 2021/0123436, each of which is hereby incorporated in its entirety, illustrate examples of pumps having an auxiliary fluid passageway or path for directing fluid to a temperature sensing element.

SUMMARY

It is an aspect of this disclosure to provide an internal temperature check point of fluid/lubricant within a pump within a pump system or assembly, to ensure safe and proper control and operation of said pump, as well as ensure a relatively higher efficiency of a motor associated therewith.

An aspect of this disclosure provides a pump system including: a housing with a pump and an electric motor therein; a pump inlet with a pump inlet port; a pump outlet with a pump outlet port; a drive shaft rotatably driven by the electric motor, for driving parts of the pump to pressurize fluid received through a main path of the pump from the pump inlet for output from an outlet path to the pump outlet; and a controller having a sensor thereon. Also in the pump system is an auxiliary circuit for temperature measurement to provide an internal temperature check point of fluid within the pump system. The auxiliary circuit deviates from the main path of the pump and is configured to direct a portion of the pressurized fluid to the sensor. The auxiliary circuit has a return path through the motor for directing the pressurized fluid in the auxiliary circuit and cooling the motor and a secondary path through the housing to return said pressurized fluid to the main path.

Another aspect of this disclosure provides a method for directing fluid in the pump system noted above. The method includes: receiving input fluid via the pump inlet port into the pump inlet and into the main path; rotatably driving the drive shaft using the electric motor for driving parts of the pump to pressurize the input fluid received through the main path; directing the portion of the pressurized fluid to the auxiliary circuit and to the sensor for temperature measurement; and directing the pressurized fluid to the return path through the motor for cooling the motor and the secondary path to return the pressurized fluid to the main path.

Other aspects, features, and advantages of the present disclosure will become apparent from the following detailed description, the accompanying drawings, and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a schematic view of a pump system in accordance with an embodiment of the disclosure.

FIG. 2 illustrates a cross-sectional view of one exemplary embodiment of parts of a pump system as shown in FIG. 1.

FIG. 3 illustrates a detailed view of an inner rotor and an outer rotor that is provided in the pump system of FIG. 2, showing an inlet port, a new outlet port, and a new outlet groove therein, in accordance with an embodiment.

FIGS. 4A-4G show rotation of the parts of FIG. 3 and displacement volume movement therein, with corresponding graphs illustrating the rotation of the outer gear (in degrees) vs. the cross-sectional area (in mm²) according to an embodiment.

FIG. 5 illustrates a cross-sectional view of another exemplary embodiment of parts of a pump system as shown in FIG. 1 in accordance with another embodiment of this disclosure.

FIG. 6 illustrates a detailed view of an inner rotor and an outer rotor that is provided in the pump system of FIG. 2, showing an inlet port, a new outlet port, and a new outlet groove therein, in accordance with another embodiment.

FIGS. 7A-7G show rotation of the parts of FIG. 6 and displacement volume movement therein, with corresponding graphs illustrating the rotation of the outer gear (in degrees) vs. the cross-sectional area (in mm²) according to an embodiment.

FIG. 8 shows an exploded view of a pump system and parts according to FIG. 2 and/or FIG. 5, including its housing and covers, in accordance with an embodiment.

FIG. 9 shows a cross-sectional view of the pump system of FIG. 8, as assembled, showing locations of journal bearings.

FIG. 10 shows an exemplary, non-limiting embodiment of a sensor and heat sink that may be utilized in the disclosed pump system(s).

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

The description set forth below in connection with the appended drawings is intended as a description of various embodiments of the disclosed subject matter and is not necessarily intended to represent the only embodiment(s). In certain instances, the description includes specific details for the purpose of providing an understanding of the disclosed embodiment(s). However, it will be apparent to those skilled in the art that the disclosed embodiment(s) may be practiced without those specific details. In some instances, well-known structures and components may be shown in block diagram form in order to avoid obscuring the concepts of the disclosed subject matter.

Reference throughout the specification to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with an embodiment is included in at least one embodiment of the subject matter disclosed. Thus, the appearance of the phrases “in one embodiment” or “in an embodiment” in various places throughout the specification is not necessarily referring to the same embodiment. Further, the particular features, structures or characteristics may be combined in any suitable manner in one or more embodiments. Further, it is intended that embodiments of the disclosed subject matter cover modifications and variations thereof.

It is to be understood that terms such as “up,” “below,” “top,” “bottom,” “side,” “upper,” “lower,” “interior,” “exterior,” “inner,” “outer,” and the like that may be used herein merely describe points of reference and do not necessarily limit embodiments of the present disclosure to any particular orientation or configuration. Furthermore, terms such as “first,” “second,” etc., merely identify one of a number of portions, components, steps, operations, functions, and/or points of reference as disclosed herein, and likewise do not necessarily limit embodiments of the present disclosure to any particular configuration or orientation, or any requirement that each number must be included.

As understood by one of ordinary skill in the art, “pump displacement” or “displacement” as used throughout this disclosure refers to a volume of liquid or fluid (e.g., lubricant, oil) a pump is capable of moving during a specified period of time, i.e., a flow rate. It is noted that the terms “fluid” and “lubricant” may be used interchangeably throughout this disclosure.

As evident by the drawings and below description, the disclosed pump system and method of operating the same includes a pump having a split outlet path that allows for positive displacement driven flow for temperature measurement circuit (including a temperature sensing element or sensor). As a result, this disclosure provides more control over the amount of lubricant (e.g., oil) or fluid being sent to auxiliary circuit (as compared to prior art like a pressure bleed orifice). In embodiments, the disclosed system may be designed to be pressure independent, with an amount of flow to the auxiliary circuit/temperature measurement and cooling path being a percentage of the total displacement of the pump. As such, the disclosed system allows auxiliary flow to be returned to the main path rather than recirculated to the inlet, providing less volumetric efficiency loss.

In one embodiment, the portion or percentage of auxiliary fluid flow of pressurized fluid through the auxiliary circuit is returned to the main path via the outlet path. In another embodiment, the portion or percentage of the auxiliary circuit may instead include a path that returns a portion of the return flow to the main path via the pump inlet.

Such designs allow for management of motors, including knowing static and dynamic temperature(s) and a flow rate of oil/lubricant for cooling. In addition, the number of sensors used in the larger system (transmission, traction motor, etc.) are shifted from a typical location (e.g., a position of a temperature sensor for oil/fluid is moved) such that functionality for a customer or a user is integrated into the disclosed pump system. Additionally, this disclosure provides a split output port and path in the pump that directs a portion of the output lubricant to said temperature sensor. Accordingly, in some embodiments the disclosed pump system may be used to provide improved accuracy with regards to controlling output and decisions (via the controller and/or processor) for lubrication.

FIG. 1 shows a schematic view of a pump system 100 or pump assembly in accordance with an embodiment herein. Pump system 100 may include an electronic pump 102, or e-pump, also referred to herein as simply a “pump 102”. In accordance with a non-limiting embodiment, pump system 100 may be a system or assembly such as described in U.S. Pat. No. 10,808,697 (U.S. Ser. No. 15/653,690) which is hereby incorporated by reference in its entirety herein, i.e., a pump assembly (or system) that has an assembly inlet for inputting fluid, an assembly outlet for outputting fluid, an electric motor contained within a motor casing, a pump having a pump housing, a drive shaft connecting the electric motor to the pump, and a controller configured to drive the electric motor. In such embodiment, the pump of the incorporated '697 application has an inlet for receiving input fluid from the assembly inlet and a transfer outlet for outputting pressurized fluid; the drive shaft is configured to be driven about an axis by the electric motor; and the pump and the electric motor are on opposing axial sides of the controller. The pump assembly of the incorporated '697 application also has a heat conductive plate positioned between the pump and the controller, for conducting heat from the controller; a transfer passage provided in the pump assembly for receiving the pressurized fluid output from the transfer outlet of the pump and directing the pressurized fluid along and in contact with the heat conductive plate to conduct heat therefrom into the pressurized fluid, and an outlet passage that communicates the transfer path with the assembly outlet to discharge the pressurized fluid. However, such assembly or system of the incorporated '697 application is not limiting. Other pump systems and/or features may be utilized.

Pump system 100 has a housing 28 flanked by covers 60, 62 that includes the pump 102 therein, which has a pump inlet 10 for receiving input fluid to direct said fluid to a pump inlet port 10A and a pump outlet 14 for outputting pressurized fluid from a pump outlet port 14A or 14B. A drive shaft 18 (see, e.g., FIGS. 2 and 6) is provided for rotation about an axis and rotatably driving parts of the pump 102 to pressurize the input fluid received through a main path 12 [from the inlet 10 for the input fluid] for output from an outlet path 15 to the outlet 14. FIG. 8 shows an exploded view of a pump system 100 and parts according to FIG. 2 and/or FIG. 5, including its housing 28 and covers (motor-side cover 60 and pump-side cover 62), in accordance with an embodiment. The drive shaft 18 is supported, for example, by journal bearings 64 and 66, shown in FIG. 9.

From the main path 12 or outlet path 15, a portion (or percentage) of the pressurized fluid or lubricant [of the total displacement of the pump] is directed to an auxiliary circuit 16, also referred to herein as a temperature measurement and cooling path 16 (or circuit), for temperature measurement. In an embodiment, this path 16 includes directing fluid/lubricant through an internal bore in the drive shaft 18, towards a heat sink 20 (optional) provided in the path, for reading by a sensor 22 associated with an electronic control unit (ECU) or controller (which is described in greater detail later). The sensor 22 may be directly exposed to the path 16 as an option instead of using the heat sink 20. However, the heat sink may optionally be used to conduct the heat to the sensor 22 without having the sensor 22 being exposed directly to the liquid being pumped. The fluid/lubricant is then redirected to a return path 24. The return path 24, in one embodiment, includes a return flow 26 for motor cooling and then a secondary path 25 through the pump housing 28 to return fluid flow to the main path 12 via outlet path 15 and then outlet 14 (see, e.g., FIG. 2) of the pump 102. In an optional, second embodiment, the return path 24 includes return flow 26 for motor cooling and then a secondary path 27 through a pump housing to return the return flow of the fluid to the pump inlet 10 (see, e.g., FIG. 5) and the main path.

The type of pump 102 and its parts provided in the pump system/assembly 100 is not limited. In an embodiment, the pump 102 has a gerotor drive, wherein an inner rotor 50, shown in an axial view in embodiments in FIG. 3 and in FIG. 6, is rotatably driven by the drive shaft 18 to in turn rotatably drive an outer rotor 52. The inner rotor 50 is fixedly secured to the shaft 18 for rotation about axis A with the drive shaft 18. A pump end of the shaft 18 is positioned within the pump cover 62, adjacent or next to the housing 28, that includes the pump inlet 10 and pump outlet 14 therein. A motor end of the drive shaft 18 is positioned adjacent to or within a motor cover 60, casing or portion. The outer rotor 52 is rotatably received in the pump housing, and particularly the pump chamber 51 thereof (as shown in FIG. 2). The pump chamber 51 and the outer surface of the outer rotor 52 are cylindrical. As is understood by one of ordinary skill in the art, rotation of the inner rotor 50 also rotates the outer rotor 52 via their intermeshed teeth to pressurize the input fluid received in areas between the complimentary parts for output from the pump 102, and thus such details are not described here. In accordance with a non-limiting embodiment herein, the inner rotor and outer rotor are part of gerotor pump and configured for operation like that which is disclosed in the aforementioned and incorporated U.S. '697 patent. In another non-limiting embodiment, the inner rotor and outer rotor are part of a gerotor pump and configured for operation like that which is disclosed in U.S. Pat. No. 5,722,815 (U.S. Ser. No. 08/515,054) which is also incorporated by reference in its entirety herein.

Other types of pump parts for pressurizing input fluid may also be used in pump in accordance with other embodiments, including gear pumps, and thus pump 102 should not be limited to gerotor-type pumps.

Also shown in each of FIGS. 3 and 6 are the inlet port 10A which receives input fluid from the pump inlet 10. For illustrative purposes only, an exemplary known or existing prior art outlet port is shown in the Figures in dashed lines in FIG. 3 to illustrate the typical position thereof. In the disclosed embodiments, however, a new outlet port and a new outlet groove are provided in the pump 102, in accordance with embodiments, in order to selectively utilize pressurized fluid within a displacement chamber and redirect a portion of said pressurized fluid to the auxiliary/temperature measurement and cooling path 16. For example, as illustrated in FIG. 3, outlet groove 40A is provided between the inlet port 10A and outlet port 14A of the pump (e.g., within the housing 28), such that fluid pressurized within the displacement area 42 (described later with reference to FIGS. 4A-4F) after receipt from the inlet port 10A is directed to and through groove 40A before output via the outlet port 14A. As shown in FIG. 2, for example, groove 40A may be provided in or near pump-side cover 62 according to an embodiment herein. Outlet groove 40A is provided in a generally linear shape with rounded edges. The inlet port 10A, outlet port 14A, and groove 40A are provided relatively below the rotors 50, 52 in the depiction of FIG. 3, i.e., on the same side (e.g., under or below the gear set) within the pump 102, in accordance with embodiments herein. In the embodiment of FIG. 6, on the other hand, the outlet groove 40B is provided between the outlet port 14B and inlet port 10A, such that fluid pressurized within the displacement area 42 (described later with reference to FIGS. 7A-7F) after output from the outlet port 14B is directed to and through groove 40B before moving back to the inlet port 10A. Outlet groove 40B is generally L-shaped with rounded edges. Again, the inlet port 10A, outlet port 14B, and groove 40B are provided relatively below the rotors 50, 52 in the depiction of FIG. 6, i.e., on the same side (e.g., under or below the gear set) within the pump 102. Additional description is provided later below.

Pump system 100 also includes an electric motor 32 (shown in FIGS. 2 and 5) and a motor drive shaft provided in housing 28. In an embodiment, the electric motor 28 may be contained by a wall and/or within a motor casing that separates the motor parts and parts of the pump 102 within the housing 28. In embodiments, the motor drive shaft and pump drive shaft 18 are the same drive shaft, i.e., one singular shaft, that extends from the pump and through the motor. In another embodiment, the motor drive shaft and pump shaft are different parts. The electric motor 32 is connected to the pump 102, its drive shaft is configured to be driven about an axis. The electric motor 32 is configured to drive the drive shaft 18 of the pump 102 via the motor drive shaft, to rotatably drive parts of the pump 102, i.e., to pressurize the input fluid.

As detailed and shown in FIGS. 2 and 5, an electronic control unit (ECU) or controller 34 used to control the pump system 100. The controller 34 is configured, among other features, to drive the drive shaft 18 of the pump. In the illustrated embodiments, the ECU is shown in the form of a printed circuit board (PCB) 34 with electrical components thereon. As noted later, a temperature sensor 22 is mounted on the controller 34 or PCB. In an embodiment, the electric motor 32 is flanked by the controller 34 and the pump 102 in the pump assembly/system 100.

FIG. 2 illustrates one exemplary embodiment of parts of a pump system 100 as shown in FIG. 1 and previously described. As shown, the auxiliary circuit 16 includes a fluid passageway defined in the outlet path 15 of the pump that deviates from the main path 12, at or near the pump outlet 14, to direct lubricant to the sensor 22 for temperature measurement and cooling of the heat generating components in the motor. In particular, the outlet path 15 of the pump includes outlet groove 40A therein that is selectively configured to receive pressurized fluid during rotation of the pump parts (described in detail later below with respect to FIGS. 4A-4F). This outlet groove 40A thus assists in creating a split flow of fluid/lubricant which is redirected from the outlet area (e.g., the outlet path 15) to a journal bearing end of the drive shaft 18, up therethrough within an internal bore of the drive shaft 18, to the heat sink pin 20 (to sensor 22). While a heat sink is illustrated, any type of transfer member or mechanism may be used to transfer lubricant to the sensor 22 for reading the temperature of the fluid, or fluid may be directed to the sensor itself. FIG. 10, for example, shows a non-limiting embodiment of a heat sink design that may be utilized in the disclosed pump system(s) with the sensor 22, including a (copper) cup that is filled with thermal paste and a glass bead type NTC.

Sensor 22 communicates with the electronic control unit (ECU) or controller (or processor) 34 used to control the pump system 100. In the illustrated embodiments, the sensor 22 is mounted on the printed circuit board (PCB) 34 in a particular position (i.e., re-positioned to be aligned with a particular path in the pump) adjacent or near the drive shaft 18. Thermal paste 30 may be provided between the sensor 22 and heat sink 20. A seal 31 may be used to secure heat sink within a portion or a wall (e.g., of the motor casing) within the housing 28.

Turning back to the circuit/path 16, after flowing to the motor end of the drive shaft 18 and to sensor 22, lubricant is then redirected to return path 24 to the pump outlet 14. As previously noted, in the embodiment of FIG. 2, the return path 24 includes a pathway of return flow 26 for motor cooling and then secondary path 25 through pump housing to return to the outlet path 15 and then the outlet 14 of the pump 102. That is, the return path 24 is provided through the motor for directing pressurized fluid in the auxiliary circuit and cooling the motor and the secondary path 25 through the housing to return the fluid to the main path 12. The return path 24 may include multiple pathways therein such that the fluid/lubricant is directed through a number of places of the motor parts. For example, the lubricant may be directed through multiple pathways through the rotor and stator components, and across the motor, such as generally shown in FIG. 2 as well as FIG. 5. Such pathways of the return path 24 may extend through the motor parts such that the lubricant is collected or directed to the pump housing 28 (positioned relatively below the motor in the depicted drawings) and thus to the secondary path 25.

Of course, it should be understood that the auxiliary circuit 16 may also assist in drawing heat, i.e., cooling, additional parts within the pump system 100 or assembly. Such parts may include, but are not limited to, cooling the controller/ECU (by way of the flow of fluid/lubricant through the path 16 and drawing heat therefrom and it components) and/or cooling the housing components used to secure the motor parts therein.

FIGS. 4A-4G show rotation of the rotors 50, 52 of FIG. 3 and movement of a displacement volume in chamber 42 therein relative to the inlet port 10A, groove 40A, and outlet port 14A, with corresponding graphs illustrating the rotation of the outer gear 52 (in degrees) vs. the cross-sectional area (in mm²) according to an embodiment. As evidenced by the figures, the displacement volume in chamber 42 is varied via rotation of the inner gear/rotor 50 relative to the rotation of the outer gear/rotor 52. FIG. 4A illustrates a volume in chamber 42 with the outer rotor 52 at 0 (zero) degrees (here, zero is selected as a convenient reference point for the discussion of what happens during rotation). The discussion herein is provided for a single volume between a pairs of rotor teeth, understanding that this is cyclically repeated for all pairs of rotor teeth as the rotors continue their rotation, As the inner rotor 50 and outer rotor 52 rotate, the chamber 42 moves across the inlet port 10A as depicted in FIG. 4B, communicating with the inlet port 10A and receiving input fluid via pump inlet 10, thereby increasing in volume and moving towards a maximum volume. The leading teeth or lobes are engaged such that the chamber 42 is isolated from the groove 40A at this instance (leading referring to the teeth/lobes ahead of the chamber 42 in the direction of travel). In FIG. 4C, the fluid volume in chamber 42 is isolated from both the inlet port 10A and groove 40A because the leading and trailing pairs of inner rotor teeth or lobes are engaged with one another at circumferential locations between the inlet port 10A and groove 40A. The recessed U-shape or other inward projection 11 of the inlet port 10A may be optionally provided to facilitate that isolation. As shown in FIGS. 4C-4D, a pressure spike in the chamber 42 results after the volume is isolated from the inlet port 10A (with maximized area and volume) and once the volume in chamber 42 has begun to be compressed. The rotors 50, 52 continue to rotate and the isolated pressurized fluid/volume within the chamber 42 is then exposed to the groove 40A, as shown in FIG. 4D, for output to the temperature measurement and cooling path 16. Since the fluid is pressurized and only open to the groove 40A or slot thereof, particularly before such fluid is exposed to the outlet port 14A, this results in positive pressure displacement of the pressurized fluid through the path 16/circuit. Such is also noted in the corresponding graph, showing an increase in area/volume to the groove. As can be seen, as the chamber 42 is coming into communication with the groove 14, the chamber 42 is being decreased, thus applying positive pressure to the liquid therein, which drives it into the path 16/circuit (and in turn that pressure drives it through the path, to the heat sink 22, and so on). Thereafter, the volume of fluid is then exposed to both the groove 40A and outlet port 14A as shown in FIG. 4E. Here, as depicted in the corresponding graph, the fluid output area/volume reaches a maximum in the groove while the output to outlet port 14A begins. Because the opening to the outlet 14A is relatively small, substantial pressure in the chamber 42 is directed to the groove 40A and the path 16/circuit. FIG. 4F shows further rotation of the rotors 50, 52 wherein the boundary of the chamber 42 is then restricted with regards to outputting to groove 40A and instead outputs to outlet port 14A. Output to the outlet port 14A is nearing a maximum while the output to the groove (and to the inlet port 10A) is restricted because of the tooth/lobe tip engagement between the training teeth. Further rotation results in further narrowing and output of the pressurized fluid from chamber 42 through outlet port 14A, as shown in FIG. 4G. As can be appreciated, each adjacent pair of teeth/lobes creates such a chamber and this is repeated throughout the rotational cycle.

In addition to the previously described advantages and improvements, such an embodiment as shown in FIGS. 2-4F, i.e., using outlet flow to direct a portion thereof through circuit/path 16 and back to the outlet 14, equates to less or minimal volumetric efficiency losses as compared to, say, typical flow from the outlet back to the inlet, and provides a pressure independent flow. This is enhanced by the return path 24 directing the oil from the path 16 to the outlet as discussed above, such that the oil or other liquid delivered for temperature sensing is also used as part of the outlet volume.

FIG. 5 illustrates another exemplary embodiment of parts of a pump system as shown in FIG. 1 in accordance with another embodiment of this disclosure. For purposes of clarity and brevity, like elements and components throughout the Figures are labeled with same designations and numbering as discussed with reference to FIGS. 2-4F. Thus, although not discussed entirely in detail herein, one of ordinary skill in the art should understand that various features associated with the system/assembly of FIGS. 5-7F are similar to those features previously discussed. Additionally, it should be understood that the features shown in each of the individual figures is not meant to be limited solely to the illustrated embodiments. That is, the features described throughout this disclosure may be interchanged and/or used with other embodiments than those they are shown and/or described with reference to.

Again, the auxiliary circuit 16 includes a fluid passageway defined in the outlet path 15 of the pump that deviates from the main path 12, at or near the pump outlet 14, to direct lubricant to the sensor 22 for temperature measurement and cooling. In particular, the outlet path 15 of the pump includes an outlet groove 40B therein that is selectively configured to receive pressurized fluid during rotation of the pump parts (described in detail later below with respect to FIGS. 7A-7F). As shown in FIG. 5, for example, groove 40B may be provided in or near pump-side cover 62 according to an embodiment herein. This outlet groove 40B thus assists in creating a split flow of fluid/lubricant which is redirected from the outlet area (e.g., the outlet path 15) to a journal bearing end of the drive shaft 18, up therethrough via its internal bore, to the heat sink pin (to sensor 22) (or other transfer member or mechanism used to transfer lubricant to the sensor 22 for reading the temperature). However, in this embodiment, in the circuit/path 16, after flowing to the motor end of the drive shaft 18 and to sensor 22, lubricant is then redirected to return path 24 to the pump inlet 10. As shown in FIG. 5, the return path 24 includes a pathway of return flow 26 for motor cooling and then secondary return to inlet path 27 through pump housing to return fluid to the inlet 10 of the pump 102 and the main path. The pressure differential between inlet path 27 and groove 40B promotes flow through the auxiliary circuit 16 (i.e., relative negative pressure of the inlet chamber draws fluid/lubricant through the circuit), but such flow is limited to the fixed percentage of the pumps total displacement as defined by the porting geometry.

FIGS. 7A-7G show rotation of the rotors 50, 52 of FIG. 5 and movement of a displacement volume in chamber 42 therein relative to the inlet port 10A, groove 40B, and outlet port 14B, with corresponding graphs illustrating the rotation of the outer gear 52 (in degrees) vs. the cross-sectional area (in mm²) according to an embodiment. As evidenced by the figures, the displacement volume in chamber 42 is moved via rotation of the inner gear/rotor 50 relative to the rotation of the outer gear/rotor 52. FIG. 7A illustrates a volume in chamber 42 with the outer rotor 52 at 0 (zero) degrees. As the inner rotor 50 rotates, the chamber 42 moves across the inlet port 10A as depicted in FIG. 7B, receiving input fluid via pump inlet 10, thereby increasing in volume as it moves towards the outlet port 14B. In FIG. 7C, the volume of fluid in chamber 42 is then exposed to the outlet port 14B for output thereto. Such is also noted in the corresponding graph, showing an increase in area/volume to the outlet. Fluid continues to be output through the outlet port 14B as the rotors 50, 52 rotate as shown in FIG. 7D. In FIG. 7E, the fluid volume in chamber 42 is then isolated from both the outlet port 14B and groove 40B because of the engagement between the leading/trailing teeth/lobes, wherein the chamber 42 has an undulating shape with the leading part thereof curved to face concave outwardly and the trailing part curved to face concave inwardly with a transition at the root of the leading tooth of the outer rotor 52. The rotors 50, 52 continue to rotate and the fluid/volume within the chamber 42 is then exposed to the groove 40B, as shown in FIG. 7F, for output to the temperature measurement and cooling path 16. Since the fluid here is only open to the groove 40B or slot thereof, and such exposure is only after output to the outlet port 14B, only a portion or percentage of the pump displacement is provided the path 16/circuit. Such is also noted in the corresponding graph, showing an increase in area/volume to the groove. However, because the chamber 42 is now isolated from the outlet port 14B, the decrease in volume of chamber 42 generates positive pressure to assist in delivering the oil or other liquid therein into to the groove 40B for delivering to the path 16/circuit. Thereafter, the maximum amount of the remaining volume of fluid then exposed to the groove 40B as shown in FIG. 7G, where the chamber 42 has decreased in size to provide the positive pressure. As depicted in the corresponding graph, the fluid output area/volume reaches a maximum in the groove while the chamber 42 is isolated from the outlet port 14A and inlet port 10A. Further rotation results in further narrowing of the chamber 42, before the cycle starts again. Similarly to the previous embodiment, each adjacent pair of teeth/lobes creates such a chamber and this is repeated throughout the rotational cycle.

In the embodiment as shown in FIGS. 5-7F, i.e., using outlet flow to direct a portion thereof through circuit/path 16 and to the inlet 10, the groove 40B and main outlet 10 are completely separate from each other, resulting in less restrictive flow. As noted, since only a portion or percentage of pump displacement is sent to the circuit 16, there may be a volumetric efficiency loss in this configuration. However, the split outlet retains flexibility for tuning the flow to the auxiliary circuit despite being more pressure dependent. With the pressure differential being connected to the inlet side (or suction side) of the pump, the amount of fluid or lubricant that is drawn through the auxiliary circuit 16 is more limited, since the amount or portion of fluid that is taken from the outlet flow is a function of such a differential.

The portion or percentage of the pump displacement/pressurized fluid provided to the auxiliary circuit or path 16 is not intended to be limited with regards to amount or volume. In an exemplary embodiment, the percentage of fluid provided to the auxiliary circuit may be in the range of approximately 1% to approximately 50%. In another exemplary embodiment, the percentage of fluid provided to the auxiliary circuit may be in the range of approximately 1% to approximately 25%. In yet another exemplary embodiment, the percentage of fluid provided to the auxiliary circuit may be in the range of approximately 1% to approximately 10%. In still yet another exemplary embodiment, the percentage of fluid provided to the auxiliary circuit may be in the range of approximately 1% to approximately 5%. In one embodiment, the percentage of fluid provided to the auxiliary circuit is approximately 5%.

It is noted that a number of features of the auxiliary circuit have been depicted in the drawings in a particular location. However, it should be noted that elements of the auxiliary circuit may be moved without deviating from the herein disclosed features and advantages. For example, according to an embodiment, the location of the sensor 22 and/or heat sink may be provided on an opposite side (e.g., left side) of the drive shaft and on the circuit board (as opposed to the right side as illustrated in FIG. 2, for example). In an embodiment, the path 16 through the internal bore of the drive shaft 18 may include radially extending passage(s) that direct fluid to the secondary path 25 of the pump housing, for example. In yet another embodiment, rather than using an opening through the pump housing to define the second path 25, the secondary path may be a passage provided in the pump housing or cover, the passage being provided in the form of a recess in an underside thereof and facing an axial side of the pump such that fluid directed to/from the auxiliary circuit and pump.

Moreover, the depictions and placement of the pump system 100 as shown in the Figures is not meant to limit the positioning or mounting of the pump system itself. That is, while the pump system 100 is shown in a vertical position such that the controller is positioned above the motor, which are both above the pump, the pump system 100 and thus its housed components may be positioned at any number of angles that are different than those shown in the Figures. For example, the pump system 100 may be turned 90 degrees towards the right, such that the pump inlet 10 and cover 62 are on the left side and the controller 34 and cover 60 on the right.

While the principles of the disclosure have been made clear in the illustrative embodiments set forth above, it will be apparent to those skilled in the art that various modifications may be made to the structure, arrangement, proportion, elements, materials, and components used in the practice of the disclosure.

It will thus be seen that the features of this disclosure have been fully and effectively accomplished. It will be realized, however, that the foregoing preferred specific embodiments have been shown and described for the purpose of illustrating the functional and structural principles of this disclosure and are subject to change without departure from such principles. Therefore, this disclosure includes all modifications encompassed within the spirit and scope of the following claims.

Claims

1. A pump system comprising:

a housing with a pump and an electric motor therein;

a pump inlet comprising a pump inlet port;

a pump outlet comprising a pump outlet port;

a drive shaft rotatably driven by the electric motor, for driving parts of the pump to pressurize fluid received through a main path of the pump from the pump inlet for output from an outlet path to the pump outlet;

a controller having a sensor thereon, and

an auxiliary circuit for temperature measurement to provide an internal temperature check point of fluid within the pump system, the auxiliary circuit deviating from the main path of the pump and configured to direct a portion of the pressurized fluid to the sensor, and

the auxiliary circuit comprising a return path through the motor for directing the pressurized fluid in the auxiliary circuit and cooling the motor and a secondary path through the housing to return said pressurized fluid to the main path.

2. The pump according to claim 1, wherein the secondary path is configured to return said pressurized fluid to the main path via the outlet path.

3. The pump according to claim 1, wherein the secondary path is configured to return said pressurized fluid to the main path via the pump inlet.

4. The pump system according to claim 1, wherein the auxiliary circuit includes a fluid passageway defined in the outlet path of the pump.

5. The pump system according to claim 1, wherein the auxiliary circuit includes a path through an internal bore in the drive shaft, for directing the pressurized fluid to the sensor.

6. The pump system according to claim 1, further comprising a heat sink within the auxiliary circuit, wherein the fluid is directed towards the heat sink for reading the temperature measurement by the sensor.

7. The pump system according to claim 1, wherein the pump is a gerotor type pump comprising an inner rotor fixedly secured to the drive shaft for rotation therewith and an outer rotor rotatably received within the housing.

8. The pump system according to claim 7, wherein a displacement volume of fluid is provided within a chamber formed between teeth of the inner rotor and the outer rotor during rotation thereof.

9. The pump system according to claim 8, further comprising an outlet groove, positioned relatively below the pump and provided between the pump inlet port and the pump outlet port, configured for selectively receiving a portion of the displacement volume of fluid within the chamber, before output via the pump outlet port or the pump inlet port, during rotation of the inner rotor and the outer rotor.

10. The pump system according to claim 9, wherein the outlet groove comprises a generally linear shape that extends radially relative to an axis for rotation of the drive shaft.

11. The pump system according to claim 9, wherein the outlet groove comprises an undulating shape.

12. The pump system according to claim 1, wherein the controller is provided in the form of a printed circuit board, and wherein the sensor is mounted thereon.

13. A method for directing fluid in a pump system, said pump system comprising the pump system of claim 1, said method comprising:

receiving input fluid via the pump inlet port into the pump inlet and into the main path;

rotatably driving the drive shaft using the electric motor for driving parts of the pump to pressurize the input fluid received through the main path;

directing the portion of the pressurized fluid to the auxiliary circuit and to the sensor for temperature measurement;

directing the pressurized fluid to the return path through the motor for cooling the motor and the secondary path to return the pressurized fluid to the main path.

14. The method according to claim 13, wherein the secondary path is configured to return said pressurized fluid to the main path via directing the outlet path.

15. The method according to claim 13, wherein the secondary path is configured to return said pressurized fluid to the main path via the pump inlet.

16. The method according to claim 13, wherein the auxiliary circuit includes a path through an internal bore in the drive shaft, and wherein the method comprise directing the pressurized fluid through the internal bore and to the sensor.