Permanent magnet rotors for axial flux motors

Abstract

An axial flux motor water pump includes: a housing; a cover attached to the housing; a stator mounted within the housing, the stator including a plurality of stator poles mounted in a ring, each stator pole including a wire winding; a rotor journaled to the housing in a mating relationship with the stator on a single bearing; an impeller fixed to the end of the rotor; a plurality of magnets mounted on the end of the rotor in mating relationship with the stator poles; a seal between the rotor and the housing so that the stator and magnets are in a dry area, the stator being heat-potted encapsulated within the housing; and electronics contained in the cover. The rotor portion of the rotor may be manufactured in a sintering process.

Description

Technical Field

[0001] Embodiments of the present invention generally relate to an axial flux motor water pump, and more particularly to an axial flux motor water pump including a mechanical seal. Additionally, some embodiments of the present invention employ a permanent magnet rotor manufactured in a sintering process. Background Art

[0002] Some embodiments of the present invention relate to a water pump for pumping a fluid, in particular a cooling fluid in an internal combustion engine or other application requiring a cooling fluid circulation pump. Axial flux motors for use with water pumps are known in the art. In an axial flux motor, the magnetic flux lines extend in an axial direction in an air gap of the motor. The stator typically includes a round wire winding.

[0003] Representative of the art is U.S. Patent Application 2015 / 0030479, which discloses a wet rotor pump with an axial flux motor, the axial flux motor comprising a stator and a rotor. The stator is arranged in the dry zone, while the rotor on the impeller is arranged in the wet zone. The rotor is formed by one or more samarium cobalt (SmCo) permanent magnets.

[0004] Representative technologies also include U.S. patent application 2017 / 0016449, which discloses a pump comprising: a housing that partially defines a cavity; an impeller that is arranged in the cavity, the impeller comprising a first disk and blades arranged on the first disk, the impeller being operable to rotate about a rotation axis; a first stator core that is arranged on the housing; a winding that is arranged on the first stator core; and a first inlet that is defined by the housing, wherein the first inlet, the impeller and the housing partially define a fluid flow path.

[0005] One disadvantage of prior art axial flux motors and other electromechanical motors is that the rotor includes one or more permanent magnets that are interconnected to a frame, such as by glue. That is, the rotor in an electric motor typically includes a permanent magnet or multiple permanent magnets fixed to a steel laminate core (or in some cases a soft metal core). These components are manufactured separately and connected by attaching the single magnet or multiple magnets to the core by press fitting, gluing or other connection methods. Prior art methods are inefficient, produce large variations between rotor components, require expensive testing procedures, and result in reduced rotor reliability and increased weight imbalance. As will be understood by those skilled in the art, the required connection processing also increases production costs.

[0006] Therefore, there is a long-standing need to provide an axial flux motor water pump that includes a mechanical seal around the stator and thermal potting. There is also a need to provide a permanent magnet rotor that is precisely balanced and has low manufacturing costs. Embodiments of the present invention meet these needs. Summary of the invention

[0007] An aspect of some embodiments of the present invention is to provide an axial flux motor water pump including a mechanical seal around a stator and a thermal potting seal.

[0008] Another aspect of some embodiments of the present invention is to provide a permanent magnet rotor manufactured by an efficient production method. Therefore, it is contemplated that one embodiment of the rotor is manufactured by a sintering process. The sintering manufacturing process can be performed in a single step or in two steps. The single-step process uses a press head that compresses the material associated with the rotor frame and magnets in a mold. The two-step process first forms a frame in a mold, and then the ferromagnetic material is placed on the pre-formed frame. Pressing the ferromagnetic material onto the pre-formed frame will produce the final rotor assembly. A person of ordinary skill in the art will understand that when an interface material is required between the frame and the ferromagnetic material, the two-step pressing process can be changed to a three-step process. Regardless of the process of manufacturing the rotor, a heating step may be required to fuse the constituent components. The process described herein contemplates the manufacture of a rotor having multiple magnetized regions or magnetized rings that cover the entire frame, which may also be referred to as a "core" herein.

[0009] One embodiment of the invention includes an axial flux motor water pump comprising: a housing; a cover attached to the housing; a stator mounted within the housing, the stator including a plurality of stator poles mounted in a ring, each stator pole including a wire winding; a rotor journaled to the housing on a single bearing in mating relation to the stator; an impeller secured to the end of the rotor; a plurality of magnets mounted on the end of the rotor in mating relation to the stator poles; a seal between the rotor and the housing so that the stator and magnets are in a dry area, the stator being heat potted within the housing; and electronics contained within the cover. In some variations of this embodiment, a sintering technique is used to manufacture the rotor.

[0010] The term "one" or "an" entity used herein refers to one or more of the entities. Therefore, the terms "one" (or "one"), "one or more" and "at least one" are used interchangeably herein. Moreover, the phrases "at least one", "one or more" and "and / or" used herein are open expressions, which are both connected and separated in operation. For example, the statements "at least one of A, B and C", "at least one of A, B or C", "one or more of A, B and C", "one or more of A, B or C" and "A, B and / or C" each mean A alone, B alone, C alone, A and B together, A and C together, B and C together or A, B and C together.

[0011] Unless otherwise indicated, all numbers expressing quantities, dimensions, conditions, and so forth, used in the specification and drawings are to be understood as approximations that can in all cases vary as required by the particular application of the novel components and methods described herein.

[0012] In this article, "include", "comprising" or "having" and their variations are meant to include the items listed later and their equivalents and additional items. Therefore, the terms "include", "comprising" or "having" and their variations are used interchangeably in this article.

[0013] It should be understood that the term "means" as used herein should be given its broadest possible interpretation in accordance with 35 U.S.C. Section 112(f). Therefore, claims containing the term "means" should cover all structures, materials, or acts described herein and all their equivalents. Moreover, the structures, materials, or acts and their equivalents should include all structures, materials, or acts and their equivalents described in the Summary of the Invention, the Description of the Figures, the Detailed Description, and the Figures.

[0014] The summary of the invention of the present invention should not be interpreted as representing the full scope of the present invention. That is, these and other aspects and advantages will be apparent through the summary of the invention described herein. Moreover, the above-mentioned embodiments, aspects, purposes and configurations are neither complete nor exhaustive. It should be understood that other embodiments of the present invention can use one or more features described above or introduced later, alone or in combination. Moreover, references to "the present invention" or its aspects herein should be understood to mean embodiments of the present invention, and should not be interpreted as limiting all embodiments to specific descriptions. The present invention is described in various degrees of detail in the summary of the invention and the accompanying drawings and specific embodiments, and the scope of the present invention is not limited by elements, parts, etc. that are included or not included in the summary of the invention. Other aspects of the present invention will be more clearly understood through specific embodiments, especially when combined with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention and, together with the summary of the invention given above and the detailed description of the drawings given below, serve to explain the principles of these inventions.

[0016] Figure 1 yes Figure 2 The cross section AA of the pump;

[0017] Figure 2 is a plan view of the pump;

[0018] Figure 3 This is the plan view of the pump

[0019] Figure 4It is a schematic coolant system;

[0020] Figure 5 It is an exploded view;

[0021] Figure 6 is a perspective view of the rotor magnets and frame;

[0022] FIG7 is a perspective view of components forming a prior art permanent magnet rotor;

[0023] FIG8 is a cross-sectional view of the assembled rotor shown in FIG7;

[0024] Figures 9A-9D A method of manufacturing a permanent magnet rotor according to one embodiment of the present invention in a single step process is shown; and

[0025] Figures 10A-10D A method of manufacturing a permanent magnet rotor according to another embodiment of the present invention in two processes is shown.

[0026] It should be understood that the accompanying drawings are not necessarily drawn to scale. In some cases, details that are not necessary for understanding the present invention or that make other details difficult to understand may be omitted. Of course, it should be understood that the present invention is not necessarily limited to the particular embodiments shown herein. DETAILED DESCRIPTION

[0027] Figure 1 yes Figure 2 Section AA of a pump. The water pump comprises an electric motor driving an impeller. The electric motor comprises an axial flux motor. In an axial flux motor, due to the orientation of the magnetic poles and the stator windings, the magnetic flux extends in an axial direction in the air gap of the motor. The water pump of the present invention is typically used in an engine cooling system. The water pump pressurizes and circulates the coolant through the engine cooling system.

[0028] The water pump 1000 includes a housing 10 and a cover 50. An impeller 150 is attached to the end of the rotor shaft 100. A stator 200 is arranged in the housing. A plurality of stator poles 201 are arranged in a ring in the inner portion 11 of the housing 10. As in the case of an axial flux motor, the axis BB of each pole 201 is parallel to the rotation axis DD of the shaft 100. The motor includes a three-phase nine-coil structure. The stator poles 201 include a soft metal composite material. Magnetic materials can also be used for the stator poles 201.

[0029] A wire winding 202 is wound around each pole 201. The winding 202 may comprise a wire having a flat cross section or a round wire. The flat wire may have a square or rectangular cross section. The flat wire or the round wire may comprise copper or aluminium. The winding plane CC of the winding 202 extends perpendicular to the axis DD of the shaft, so that the magnetic flux extends in the axial direction (parallel to the axis DD). The motor of the present invention has a rated power of 200 W up to 12 kW.

[0030] A plurality of permanent magnets 110 are mounted to the other end of the shaft 100 on a frame 115. The magnet 110 may also include a single ring magnet having a plurality of poles. The frame 115 is fixed to the end of the shaft 100 so as to rotate with the shaft 100. The magnet 110 is radially aligned with the pole 201. An air gap "G" is maintained between the pole 201 and the magnet 110 to prevent contact between them during operation. The air gap is in the range of 0.2 mm to 1.5 mm. The gap "G" is preferably as small as possible to achieve maximum magnetic efficiency.

[0031] Mechanical seal 250 prevents pressurized liquid coolant from entering inner part 11, thereby preventing pressurized liquid coolant from contacting stator 200 and rotor magnet 110, so stator 200 and magnet 110 are in a dry area. The dry area is usually at ambient atmospheric pressure. Seal 250 is arranged between shaft 100 and housing 10. Seal 250 may include any suitable mechanical seal known in the art, such as bellows, cylinder, balance cylinder and O-ring, unbalanced cylinder and O-ring, pusher and conventional type of seal. Maintaining a dry space for stator and magnet will improve the efficiency of the pump by reducing windage and viscous losses (otherwise when the inner part 11 contains coolant and the coolant is therefore present in the gap "G" between the stator poles and the rotor magnets, there will be said windage and viscous losses).

[0032] The condensate chamber and reservoir 301 includes a vent hole 302 and a drain hole 303. The chamber 301 collects any fluid that may leak through the seal 250. The vent hole 302 and drain hole 303 are open to the environment.

[0033] A thermal pot 12 is used in the housing 10 to encase the stator 200. The thermal pot allows the pump to run cooler by providing a reliable means of heat transfer from the stator and housing. Pump heating is typically caused by resistive heating caused by iron and copper losses and eddy currents induced in the stator and windings by the changing magnetic field, conducted from the pumped cooling fluid to the housing and from the engine block (not shown) to the housing. Thermal potting is known in the electrical arts.

[0034] The shaft 100 rotates in a single bearing 120. The bearing 120 may also include an integral bearing, wherein the shaft 100 includes an inner race of the bearing. The rotating assembly includes the shaft 100, the frame 115, the magnet 110, and the impeller 150. The single bearing 120 may include a double row ball bearing or a double row ball roller bearing. The roller bearing may include cylindrical or tapered rollers. The shorter length of the pump shaft provided by the axial flux motor construction enables the use of a single bearing. The bearing includes a sealed bearing. Due to the shorter overall length of the shaft 100, the impeller 150 is cantilevered on the shaft 100.

[0035] Coolant flows into the impeller inlet 151 and is discharged from the outlet 152 as the impeller rotates. Impellers are known in the field of water pumps. Typical operating discharge pressures may be up to about 1.5 bar, but may vary to over 5 bar depending on the thermal load of the engine. Depending on the application, the volume flow may be up to 220 liters / minute, or higher to 500 lpm.

[0036] The electronics are arranged in the electronics housing 51 in the cover 50. The electronics control the shaft rotation speed and can also detect faults. Axial flux motor electronics are known in the art. The cover 50 acts as a heat sink to cool the electronics. The motor is variable speed, which can adjust the coolant fluid flow according to the thermal load requirements of the engine. Control methods include PWM, LIN protocol / bus or CAN protocol / bus. The LIN bus is a sub-bus system based on a serial communication protocol. The bus is a single master / multi-slave bus that uses a single wire to transmit data. The controller area network or CAN protocol is a communication method between various electronic devices, such as engine management systems, water pumps, oil pumps, active suspensions, ABS, gear controls, lighting controls, air conditioning, air bags, central locks embedded in cars. PWM or pulse width modulation is a type of digital signal used in various applications including control circuits.

[0037] Figure 2 is a plan view of the pump. The discharge volute 13 engages with a mating channel in the engine block (not shown). The housing 10 is mounted directly on the engine block. The suction side or inlet side 150 matingly engages with a fluid conduit (not shown) in the engine.

[0038] Figure 3 is a plan view of the pump. Fasteners (not shown) engage mounting holes 14 to attach the pump to a mounting surface such as an engine block (not shown).

[0039] Figure 4 1 is a schematic coolant system. A pump 1000 is mounted on an engine (E). The engine (E) includes three cylinders (1), (2), (3). The engine (E) may include any number of cylinders as desired. A water jacket (J) surrounds the cylinders. The system also includes a radiator (R), an engine transmission oil heat exchanger (OC), an auxiliary heat exchanger (AUX), and an exhaust manifold heat exchanger (EM).

[0040] Thermal management module 2000 is mounted on the suction side of pump 1000. Module 2000 includes multiple valves 2001, 2002, 2003, 2004, 2005 and 2006. Each valve controls the coolant flow for system components. Valve 2001 controls the flow to radiator R. Valve 2002 controls the flow to heat exchanger OC. Valve 2003 controls the flow to heat exchanger AUX. Valve 2004 controls the return flow from R, OC, AUX and EM. Valve 2005 controls the recirculation flow from pump 1000 and the flow to EM. Valve 2006 controls the return flow from E, EM, AUX, OC and R. The engine ECU detects engine and system conditions, environmental conditions, and system and driver requirements through multiple sensors and input signals (3001) to set each valve in an appropriate position to adjust the coolant flow, thereby controlling the thermal performance of the engine and system. Each valve is in fluid communication with the pump inlet 151 .

[0041] Figure 5 is an exploded view. The motor is a three-phase motor. Winding 202(a) is the first phase. Winding 202(b) is the second phase. Winding 202(c) is the third phase. In this embodiment, each phase includes three stator poles. However, windings for each pole connected to a single phase or multiple phases can also be used. Gasket 15 is sealed between the housing 10 and the engine E.

[0042] Figure 6 is a perspective view of the rotor magnets and the frame. The magnets 110 are mounted on a frame 115. The frame 115 is pressed onto the shaft 100. The frame 115 may also include blades to circulate cooling air.

[0043] The magnet 110 may include a ring magnet having poles around the circumference, or may include a plurality of individual magnets having poles in alternating positions. The magnet may include ferrite, rare earth or other known materials. The magnet is attached to the frame using known methods.

[0044] 7 and 8 show a prior art permanent magnet rotor 700, which includes a permanent magnet 710 adhered to a frame 715. It should be understood by those skilled in the art that in some cases, the permanent magnet 710 is fixed to the frame 715 using glue, but other interconnection mechanisms are generally used, such as interference fit, welding, etc.

[0045] Figures 9A-9D900 of the present invention is shown. Here, a mold 920 is filled with a powder material 924 that will eventually be connected to the frame 915 of the rotor. A second powder material 928 is then added to the mold 920 above the first material 924. The combined materials are then compressed using a punch 932 to form the final shape of the rotor 900. It will be appreciated by those of ordinary skill in the art that a heat treatment may be required to enhance the bonding between the constituent components that form the rotor. Finally, a magnet 936 is introduced to the rotor 900 near the magnet side 910 to magnetize it using known methods.

[0046] Figures 10A-10D A two-step method for manufacturing the rotor 900 of the present invention is shown. In this process, material 924 associated with the frame 915 is added to the die 920 and compressed with a punch 932. Then, a second powder material 928 comprising a ferromagnetic material is added to the die 920 above the forming frame 915 and compressed to form the rotor 900. Heat treatment may be required to enhance the bonding between the component parts. As described above, the third component can be used in any of the above methods to enhance the bonding between the component materials. Finally, the magnet 936 is introduced to the rotor 900 near the magnet side 910 to magnetize it using known methods.

[0047] Although the form of the invention has been described herein, it is apparent to those skilled in the art that the structure and relationship of the components can be varied without departing from the spirit and scope of the invention as described herein. Unless otherwise specifically stated, the components depicted in the drawings are not drawn to scale. Numerical examples are used to illustrate the invention and do not limit the breadth of the claims. Moreover, USC § 112 (f) is not invoked in any additional claim or claim element unless the words "device for..." or "step for..." are explicitly used in a particular claim. The present invention is in no way limited to the example embodiments or numerical dimensions shown in the drawings and described herein.

[0048] Although various embodiments of the present invention have been described in detail, it is obvious that variations and changes of these embodiments will occur to those skilled in the art. It should be clearly understood that these variations and changes are within the scope and spirit of the present invention, as described in the subsequent claims. Moreover, it should be understood that the invention described herein is not limited to its application to the construction details and component arrangements described in the preceding description or shown in the accompanying drawings. The present invention is capable of other embodiments and can be practiced or implemented in various ways. In addition, it should be understood that the words and terms used herein are for illustrative purposes and should not be considered as limitations. The use of "including", "comprising" or "having" and their variations herein means to include the items listed later and their equivalents and additional items.

Claims

1. An axial flux motor water pump, comprising: case; a cover attached to the housing; a stator mounted within the housing, the stator comprising a plurality of stator poles mounted in a ring, each stator pole comprising a wire winding; A rotor journaled to the housing in mating relation to the stator on a single bearing, the rotor being manufactured in a sintering process comprising: adding a first material to the mold, adding a second material to the mold over the first material, compressing the first material and the second material within the mold, and magnetizing a second material; an impeller fixed to the end of the rotor; a plurality of magnets mounted on the ends of the rotor in mating relation with the stator poles; seals, which are between the rotor and the housing, so that the stator and magnets are in a dry area, The stator is heat-potted and enclosed in the housing; and an electronic device contained in the cover; A condensate chamber for collecting any fluid that may leak through the seal includes a vent and drain hole that are open to the environment.

2. The axial flux motor water pump according to claim 1, wherein: The wire windings include flat wires.

3. The axial flux motor water pump according to claim 1, wherein: The wire windings include round wires.

4. The axial flux motor water pump according to claim 1, wherein: The rotor journal is connected to a double-row ball bearing.

5. The axial flux motor water pump according to claim 1, wherein: The impeller is mounted on the rotor in a cantilevered manner.

6. An axial flux motor water pump, comprising: case; a cover attached to the housing; a stator mounted within the housing, the stator comprising a plurality of stator poles mounted in a ring, each stator pole comprising a wire winding; A rotor journaled to the housing in mating relation to the stator on a single bearing, the rotor being manufactured in a sintering process comprising: adding a first material to the mold, compressing the first material to form a rotor frame, adding a second ferromagnetic material to the mold above the rotor frame; and compressing a second ferromagnetic material onto the rotor frame; an impeller fixed to the end of the rotor; a plurality of magnets mounted on the ends of the rotor in mating relation with the stator poles; seals, which are between the rotor and the housing, so that the stator and magnets are in a dry area, The stator is heat potted in the housing; and an electronic device contained in the cover; A condensate chamber for collecting any fluid that may leak through the seal includes a vent and drain hole that are open to the environment.

7. The axial flux motor water pump according to claim 6, wherein: The wire windings include flat wires.

8. The axial flux motor water pump according to claim 6, wherein: The wire windings include round wires.

9. The axial flux motor water pump according to claim 6, wherein: The rotor journal is connected on double row ball bearings.

10. The axial flux motor water pump according to claim 6, wherein: The impeller is mounted on the rotor in a cantilevered manner.

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