Built-in permanent magnet motor with active cooling

Abstract

An embedded permanent magnet motor includes: a housing, a liquid collection tank, and a fluid transfer system for transferring fluid from the liquid collection tank to various parts of the housing; a rotor having a shaft, a first end plate, a second end plate, a center plate, a plurality of magnets, and a plurality of channels; the shaft having a first end, a second end, and an intermediate section; the first end plate and the second end plate being located near the first end and the second end on the intermediate section of the shaft; the center plate being disposed between the first end plate and the second end plate; the plurality of magnets being disposed in circumferentially arranged magnet slots within the center plate; and the plurality of channels being formed within the first end plate, the center plate, and the second end plate for allowing fluid to flow through the rotor; and a stator located within the housing surrounding the rotor for receiving electricity and driving the rotor to rotate.

Description

Technical Field

[0001] This disclosure relates generally to built-in permanent magnet (IPM) motors, and more specifically to cooling systems within IPM motors. Background Technology

[0002] An electric motor is a fundamental device that converts electrical energy into mechanical energy. They are widely used across various industries, powering a wide range of devices from household appliances and industrial machinery to electric vehicles and aerospace systems. The basic working principle of an electric motor is to utilize the interaction between a magnetic field and an electric current within the motor components to generate the rotational force required for mechanical operation. An electric motor typically consists of a stator and a rotor. The stator absorbs current and generates a magnetic field, while the rotor usually includes a shaft with surface-mounted magnets, such that the magnetic field generated by the stator drives the rotor to rotate.

[0003] Built-in permanent magnet (IPM) motors are becoming increasingly important in a variety of applications due to their high efficiency, high power density, and robust performance characteristics. These motors are characterized by permanent magnets embedded within the rotor, rather than mounted on the surface, which offers several distinct advantages compared to traditional motor designs.

[0004] One of the main benefits of IPM motors is their ability to produce both high torque and high speed performance. Embedded magnets generate a stronger and more stable magnetic field, allowing the motor to operate over a wide speed range. This makes IPM motors particularly suitable for applications requiring variable speeds and high torque, such as electric vehicles, where both acceleration and electrical efficiency are critical.

[0005] Another advantage of IPM motors is their enhanced durability and reliability. By embedding the magnets within the rotor, these magnets are better protected from physical damage and demagnetization, which can be a problem in surface-mount magnet designs. Additionally, placing the magnets inside the rotor reduces the centrifugal forces acting on these magnets during high-speed rotation, further extending the motor's lifespan.

[0006] Despite these advantages, the design and optimization of IPM motors still face several technical challenges. Specifically, IPM motors can operate at higher temperatures than surface-mount magnet motors. Higher temperatures can cause demagnetization of the embedded magnets, leading to a decrease in IPM motor performance and a shortened lifespan.

[0007] Other rotors already used in existing IPM motor assemblies provide cooling channels within the rotor body to cool the motor. U.S. Publication No. 2023 / 0299642 A1 discloses one such rotor in which the channels are located within the rotor body. A hollow rotor shaft supplies cooling fluid to the channels from one end of the rotor to the other, and excess fluid can be thrown from the rotor's outlet end onto the stator of the IPM motor.

[0008] In view of the above-mentioned drawbacks, there is still a need for an IPM motor with an internal cooling system that can cool the IPM motor more effectively and more specifically the embedded magnets of the IPM motor. Summary of the Invention

[0009] According to one aspect of this disclosure, an embedded permanent magnet (IPM) motor can be provided. The IPM motor may include a housing comprising a collection tank and a fluid transfer system configured to transfer fluid from the collection tank to a rotor. The IPM motor may include a rotor comprising a shaft having a first end, a second end, and an intermediate section. The rotor may further include a first end plate and a second end plate disposed near the first and second ends on the intermediate section of the shaft, wherein the rotor is disposed on the intermediate section between the first and second end plates. The rotor may include a plurality of magnets disposed in a plurality of magnet slots arranged circumferentially within a central plate. The rotor may include a plurality of channels formed within the first end plate, the central plate, and the second end plate, the channels being configured to allow fluid to flow in from the channel inlets, through the channels within the rotor, and out from the channel outlets. The IPM motor may include a stator disposed within the housing surrounding the rotor and configured to receive power and drive the rotor to rotate.

[0010] According to another aspect of this disclosure, a rotor configured for use in an integrated permanent magnet motor can be provided. The rotor may include a shaft having a first end, a second end, and an intermediate section. The rotor may include a first end plate disposed on the intermediate section of the shaft near the first end. The rotor may include a second end plate disposed on the intermediate section of the shaft near the second end. The rotor may include a center plate disposed on the intermediate section of the shaft between the first and second end plates. The rotor may include a magnet disposed in a magnet slot in the center plate, the magnet being configured to interact with the stator of the integrated permanent magnet motor to generate rotation of the rotor. The rotor may include a channel formed within the first end plate, the center plate, and the second end plate, the channel being configured to allow fluid to flow from a channel inlet in the first or second end plate to a channel outlet on the other side of the first or second end plate, the channel being disposed in the center plate near the magnet.

[0011] According to another aspect of this disclosure, a method for operating an integrated permanent magnet motor can be provided. The method may include providing the integrated permanent magnet motor, which includes a stator and a rotor disposed within a housing. The rotor has a shaft, a first end plate, a second end plate, and a center plate. The shaft has a first end and a second end. The method may include transferring fluid from a collection tank of the integrated permanent magnet motor to the first and second end plates of the rotor. The method may include collecting the fluid in an inlet annular cavity in the first and second end plates, the inlet annular cavity being connected to a plurality of channels disposed within the first, center, and second end plates, such that fluid pressure accumulates in the inlet annular cavity and causes the fluid to flow through the plurality of channels. The method may include collecting the fluid in an outlet annular cavity disposed in the first and second end plates, such that an outlet fluid dam is formed in the outlet annular cavity. The method may include allowing excess fluid to flow from the outlet fluid dam to the stator and back to the collection tank.

[0012] These and other aspects and features of this disclosure will be more readily understood when read in conjunction with the accompanying drawings. Attached Figure Description

[0013] Figure 1 This is a cross-sectional view of an IPM motor constructed according to an embodiment of the present disclosure.

[0014] Figure 2 This is a perspective view of the rotor of an IPM motor constructed according to an embodiment of the present disclosure.

[0015] Figure 3 This is a cross-sectional view of the rotor of an IPM motor constructed according to an embodiment of the present disclosure.

[0016] Figure 4 This is a perspective view of the end plate of the rotor of an IPM motor constructed according to an embodiment of the present disclosure.

[0017] Figure 5 This is a front view of the center plate of the rotor of an IPM motor constructed according to an embodiment of the present disclosure.

[0018] Figure 6 It is constructed according to embodiments of this disclosure. Figure 5 An enhanced view of the center panel.

[0019] Figure 7 This is an enhanced view of an alternative center plate of the rotor of an IPM motor constructed according to an embodiment of the present disclosure.

[0020] Figure 8 This is a cross-sectional view of the stator and rotor of an IPM motor constructed according to an embodiment of the present disclosure, the cross-sectional view indicating the flow path of cooling fluid through the rotor.

[0021] Figure 9 This is a perspective view of the fluid passage within the rotor of an IPM motor constructed according to embodiments of the present disclosure.

[0022] Figure 10 It is a perspective view of a plurality of channels arranged around the rotor of an IPM motor constructed according to an embodiment of the present disclosure.

[0023] Figure 11 It is a perspective view of a plurality of channels arranged around the rotor of an IPM motor constructed according to an embodiment of the present disclosure.

[0024] Figure 12 It is a perspective view of a plurality of channels arranged around the rotor of an IPM motor constructed according to an embodiment of the present disclosure.

[0025] Figure 13 It is a perspective view of a plurality of channels arranged around the rotor of an IPM motor constructed according to an embodiment of the present disclosure.

[0026] Figure 14 It describes the fluid constructed according to embodiments of this disclosure. Figures 10 to 14 A flowchart illustrating the exemplary flow of multiple channels.

[0027] Figure 15 This is a cross-sectional view of the stator and rotor of an IPM motor constructed according to the present disclosure, the cross-sectional view indicating a first alternative embodiment of the flow path of cooling fluid through the rotor.

[0028] Figure 16 This is a cross-sectional view of the stator and rotor of an IPM motor constructed according to the present disclosure, which indicates a second alternative embodiment of the flow path of cooling fluid through the rotor.

[0029] Figure 17 This is a cross-sectional view of the stator and rotor of an IPM motor constructed according to the present disclosure, the cross-sectional view indicating a first alternative embodiment of the flow path of cooling fluid through the rotor.

[0030] Figure 18 This is a flowchart depicting an example sequence of steps for operating a built-in permanent magnet motor, which can be implemented based on the built-in permanent magnet motor and rotor of this disclosure.

[0031] The accompanying drawings illustrate one embodiment of the invention for illustrative purposes only. Those skilled in the art will readily recognize from the following discussion that alternative embodiments of the structures and methods shown herein can be employed without departing from the principles described herein. Detailed Implementation

[0032] Now refer to the attached diagram, and specifically refer to... Figure 1 The present invention describes an integrated permanent magnet (IPM) motor, and is generally referred to as such by reference numeral 10. The IPM motor 10 is exemplarily embodied as an electric IPM motor 10. While the IPM motor 10 is thus depicted, it should be noted that the IPM motor used is merely exemplary and illustrative in nature. It should be acknowledged that the teachings of this disclosure can be similarly applied to IPM motors used in various fields, including but not limited to electric vehicles, industrial machinery, household appliances, and other types of machinery utilizing IPM motors as known to those skilled in the art.

[0033] An IPM motor can be used to convert electrical energy into mechanical energy. The IPM motor 10 may include a rotor 40, which includes a shaft 41 having a first end 42, a second end 43, and an intermediate section 62. Figure 2 An exemplary embodiment of the rotor 40 is depicted in perspective view. The rotor 40 may include a first end plate 45 and a second end plate 46 disposed on an intermediate section 62 of the shaft 41. The rotor 40 may also include a center plate disposed on the intermediate section 62 between the first end plate 45 and the second end plate 46. Figure 2 As depicted in the exemplary embodiments, the center plate may include a plurality of center plates 70, thereby forming a plurality of layers. Figures 1 to 2 As depicted, the plurality of center plates 70 may include four center plates; however, any number of center plates 70 may be used as needed. In some embodiments, the plurality of center plates 70 may include a plurality of metal plates.

[0034] The rotor 40 can be configured to rotate within the IPM motor 10 at a speed of approximately 6,000 to 7,000 revolutions per minute, and therefore, the rotor 40 may require balancing. In other embodiments, the rotor 40 can be configured to rotate at any other speed, including higher speeds, as needed. Thus, each of the first end plate 45, the second end plate 46, and the plurality of center plates 70 can be cylindrical with a circular cross-section.

[0035] The rotor 40 may have embedded permanent magnets to convert the magnetic field into rotational mechanical motion. Therefore, the rotor 40 may include a plurality of magnets 80 disposed within a plurality of circumferentially arranged magnet slots (76, 77) within a plurality of center plates 70. Each magnet slot (76, 77) may include a single magnet from the plurality of magnets 80, or each magnet 80 may span the width of the plurality of center plates 70 such that the plurality of magnet slots (76, 77) are aligned with each other, and each of the plurality of center plates 70 cannot rotate relative to each other.

[0036] The rotor 40 of the IPM motor 10 generates heat as a byproduct of the induced magnetic field and mechanical rotational energy. Excessive heat on the multiple magnets 80 may cause one or more of the magnets 80 to demagnetize, and may lead to a decrease in the performance and a shortened lifespan of the IPM motor. To reduce the temperature within the rotor 40, the rotor 40 may include multiple channels 100 formed within a first end plate 45, multiple center plates 70, and a second end plate 46. The multiple channels 100 may be configured to allow fluid to flow in from multiple channel inlets 50, through the multiple channels 100 within the rotor 40, and out from multiple channel outlets 51.

[0037] The IPM motor 10 may have a housing 20 for covering the internal components of the IPM motor 10. The IPM motor 10 may require cooling and lubrication, and therefore, the housing 20 may include a liquid collection tank 21 and a fluid transfer system 22 configured to transfer fluid from the liquid collection tank 21 to the rotor 40. The fluid may be lubricating oil, cooling oil, cooling fluid, or any other known fluid.

[0038] Figure 1 An exemplary embodiment of the IPM motor 10 is depicted in cross-sectional view. The stator 30 may be disposed within the housing 20 surrounding the rotor 40 and may be configured to receive electrical power and generate a magnetic field, thereby driving the rotor 40 to rotate. The rotor 40 may be disposed within the housing 20 and supported by bearings 24 to facilitate rotation. Figure 1As depicted, rotor 40 is supported by two bearings, one at each end. Fluid delivery system 22 delivers fluid to fluid nozzle 23. Fluid nozzle 23 can be a precision oil nozzle, or any other known and necessary nozzle. Figure 1 As depicted, a plurality of fluid nozzles 23 are depicted as being uniformly oriented circumferentially around the rotor 40. Ideally, between two and twelve of the fluid nozzles 23 are uniformly oriented around the rotor 40, wherein preferably, six of the fluid nozzles 23 are located on each side of the rotor 40, thereby spraying fluid toward the first end plate 45 and the second end plate 46 of the rotor 40. However, any number of fluid nozzles 23 may be used depending on the needs of various factors, such as the required flow rate within the rotor 40, the distance from the first end plate 45 and the second end plate 46 to the stator 30, and the required flow rate of each of the fluid nozzles 23.

[0039] Figure 2 An exemplary embodiment of the rotor 40 is depicted. As shown, the shaft 41 of the rotor 40 may include a plurality of splines 44 at a first end 42 for connecting the shaft 41 of the rotor 40 to an output end. In the exemplary embodiment, the output end may be a gear of another machine; however, the output end may also be any known mechanical system suitable for coupling to the shaft 41.

[0040] The first end plate 45 and the second end plate 46 may be substantially similar to each other. The first end plate 45 and the second end plate 46 may each have an outer plate surface 47 and an inner plate surface 48. Figure 4 An exemplary embodiment of the inner panel surface 48 is depicted. The inner panel surface 48 may include portions of a plurality of channels 100, which are machined into the inner panel surface 48 or formed by any other known manufacturing process. Figure 4 As depicted, the inner plate surface 48 includes fastener holes 49, a channel inlet 50, a channel outlet 51, an inner channel connector 52, an outer channel connector 53, and a bridging connector 54 connected to a vent 55. The vent 55 may be an opening in the first end plate 45 or the second end plate 46 near its central portion. The vent 55 may be connected to the bridging connector 54, thereby connecting the channels as a whole to atmospheric pressure, allowing the multiple channels 100 to release pressure dependence. Figure 4 The embodiments include an integer number of each of the fastener hole 49, channel inlet 50, channel outlet 51, inner channel connector 52, outer channel connector 53, bridging connector 54, and vent 55, such that several of the multiple channels 100 can be accommodated within the rotor 40.

[0041] Figure 3A cross-section of a portion of the rotor 40 is depicted. The first end plate 45, the plurality of center plates 70, and the second end plate 46 can be fastened together using a sealing plate fastener 57 extending through each of the fastener holes 49 in the end plate and the fastener holes 72 in the plurality of center plates 70. A shaft sealing plate 56 can be disposed on the outer surface 47 of the first end plate 45 and the second end plate 46, such that the fastened plate seals against the shaft 41.

[0042] The outer plate surface 47 may include features that allow the rotor 40 to receive fluid delivered by the fluid nozzle 23 and to build up pressure in the fluid, causing the fluid to flow through the multiple channels 100. The outer plate surface 47 may include an inlet annular cavity 101 disposed on the outer plate surface 47, connected to the channel inlet 50, the inlet annular cavity 101 being configured to receive and collect the ejected fluid from the fluid nozzle 23, causing fluid pressure to build up within the inlet annular cavity 101 and causing the fluid to flow through the multiple channels 100. The inlet annular cavity 101 may include curved features on the outer plate surface that facilitate the guidance of fluid into the inlet annular cavity 101. The centrifugal force generated by the rotation of the rotor 40 forces fluid into the radially outward portion of the inlet annular cavity 101, where pressure builds up until the natural pumping action generated by the rotation delivers the fluid from the inlet annular cavity 101 into the multiple channels 100. An inlet annular plate 58 may be disposed on the outer plate surface 47 to define the outer wall of the inlet annular cavity 101; however, the inlet annular cavity 101 may be formed entirely within the outer plate surface 47. The introduction of the inlet annular plate 58 can facilitate the simplification of the manufacture of the outer plate surface 47 in the first end plate 45 and the second end plate 46. The inlet annular plate 58 may be attached to the outer plate surface using inlet plate fasteners 59; however, any other fastening technique for attaching the inlet annular plate 58 to the outer plate surface 47 may also be used.

[0043] The outer plate surface 47 may also include an outlet annular cavity 102 disposed on the outer plate surface 47, which is connected to the channel outlet 51. The outlet annular cavity 102 is configured to collect fluid from the channel outlet 51 and establish an outlet fluid dam. The centrifugal force generated by the rotation of the rotor 40 similarly forces the fluid in the outlet annular cavity 102 to form an outlet fluid dam until excess fluid accumulates. This excess fluid is squeezed out of the outlet annular cavity 102 and, due to centrifugal force, is thrown outward from the rotor 40 and falls onto the stator 30, thereby providing cooling to the stator 30. Once thrown out from the rotor 40, the fluid can drip from the stator 30 and fall back into the collection tank 21 within the housing 20.

[0044] Figures 5 to 7A front view and an enlarged view of one of the multiple center plates 70 are depicted. Each of the multiple center plates 70 is formed by a plate body 71, which is generally cylindrical, in other words, has a circular cross-section. The plate body 71 may include fastener holes 72 for mounting adjacent center plates of the multiple center plates 70 to a first end plate 45 and a second end plate 46. The plate body 71 may include cutouts 73 to reduce the mass of the plate body 71 and balance its rotation, thereby facilitating smoother rotation of the rotor 40. A plurality of channels 100 may be defined by the plate body, wherein each of the plurality of channels 100 includes a plurality of inner channels 74 and a plurality of outer channels 75 adjacent to magnet slots in the plate body 71 for receiving a plurality of magnets 80. Figures 5 to 6 As depicted in the embodiments, the plurality of magnets 80 may include two different sets of magnets with different sizes, each set of magnets having a corresponding magnet slot, the magnet slot including a lower magnet slot 76 and an upper magnet slot 77. Figure 7 The embodiment includes only one set of magnets and only a lower magnet slot 76. Any number and any size of magnets 80 can be used within the plate 71. The multiple magnets 80 can be evenly arranged around the outer circumference of the plate 71.

[0045] Multiple inner channels 74 and multiple outer channels 75 can be located within the plate 71, close to the multiple magnets 80. Therefore, fluid transported through the multiple inner channels 74 and multiple outer channels 75 can effectively cool the multiple magnets 80. The multiple inner channels 74 and multiple outer channels 75 can be substantially similar, having the same cross-sectional design. However, the cross-sectional design of the multiple inner channels 74 may differ substantially from the cross-sectional design of the multiple outer channels 75. Figures 5 to 6 The depicted cross-sections are identical, featuring a circular cross-section. For example... Figure 7 The depicted cross-sectional designs differ, with multiple inner channels 74 having horseshoe-shaped cross-sections and multiple outer channels 75 having slot-shaped cross-sections. The cross-sectional designs can adopt any shape as needed, including horseshoe, circular, slot-shaped, arc-shaped slots, and star-shaped, etc. The dimensions of each cross-sectional design can also be modified to achieve specific cooling targets.

[0046] Figure 8The flow path of fluid within rotor 40 in an exemplary embodiment is illustrated. Fluid is directed toward rotor 40 via fluid nozzle 23 and toward inlet annular cavity 101 (200). Fluid accumulates in inlet annular cavity 101 until sufficient pressure is generated to guide fluid through multiple channels 100, inner channel connector 52, and outer channel connector 53, and into outlet annular cavity 102 (201). Excess fluid builds a dam in outlet annular cavity 102 and flows out of rotor 40, being thrown off rotor 40 and falling onto stator 30 (203). Additionally, excess fluid may accumulate and overflow in inlet annular cavity 101 and be directly directed toward outlet annular cavity 102 to more quickly build an excess fluid dam (204).

[0047] Several of the multiple channels 100 can be arranged around the rotor 40. Figures 9 to 14 Multiple channels with tubular structures are illustrated for better observation. In an exemplary embodiment of the rotor 40, the multiple channels 100 are formed by grooves and holes in the first end plate 45, the second end plate 46, and the multiple center plates 70. As illustrated, the multiple channels 100 can extend back and forth several times within the rotor to form a serpentine pattern.

[0048] Figure 9 and Figure 10 A first channel 110 of a plurality of channels 100 is illustrated by way of example. The first channel 110 may include a first inlet 111, a plurality of first inner channels 112, and a plurality of first inner channel connectors 113 connecting the plurality of first inner channels 112 in series. The first channel 110 may include a plurality of first outer channels 116, a first bridging connector 114 connecting the plurality of first inner channels 112 to the plurality of first outer channels 116, a plurality of first outer channel connectors 117 connecting the plurality of first outer channels 116 in series, and a first outlet 118. Fluid can flow from the first inlet 111 to the first outlet 118 through the first channel 110 along a continuous, uninterrupted path.

[0049] Figures 10 to 13A rotor 40 is depicted having four of a plurality of channels 100, which are uniformly arranged around the rotor 40 and connected to an inlet annular cavity 101 and an outlet annular cavity 102 in both a first end plate 45 and a second end plate 46. The first channel 110 and the second channel 120 are oriented relative to each other such that a third channel 130 and a fourth channel 140 are adjacent to the first channel 110 and the second channel 120. The first channel 110 and the second channel 120 are arranged to flow in the opposite direction to the third channel 130 and the fourth channel 140. Therefore, the first channel 110 and the second channel 120 draw fluid from the inlet annular cavity 101 in the first end plate 45 and return excess fluid to the outlet annular cavity 102 in the first end plate 45. The third channel 130 and the fourth channel 140 draw fluid from the inlet annular cavity 101 in the second end plate 46 and return excess fluid to the outlet annular cavity 102 in the second end plate 46.

[0050] Figure 10 A first channel 110 is depicted. A first inlet 111 draws fluid from an inlet annular cavity 101 disposed in a first end plate 45 and allows the fluid to flow through the first channel 110. Centrifugal force generated by the rotation of the rotor 40 and pressure accumulating within the inlet annular cavity 101 force the fluid to flow through a plurality of first inner channels 112 and a plurality of first inner channel connectors 113. Centrifugal force and atmospheric pressure generated by a first vent 115 force the fluid to flow through a first bridging connector 114 to a plurality of first outer channels 116 and a plurality of first outer channel connectors 117. Fluid exits from the first channel 110 at a first outlet 118 and deposits in an outlet annular cavity 102 in the first end plate 45.

[0051] Figure 11 A second channel 120 is depicted. A second inlet 121 draws fluid from an inlet annular cavity 101 located in the first end plate 45 and allows the fluid to flow through the second channel 120. The centrifugal force generated by the rotation of the rotor 40 and the pressure accumulated within the inlet annular cavity 101 force the fluid to flow through a plurality of second inner channels 122 and a plurality of second inner channel connectors 123. The centrifugal force and atmospheric pressure generated by the second vent 125 force the fluid to flow through a second bridging connector 124 to a plurality of second outer channels 126 and a plurality of second outer channel connectors 127. The fluid exits the second channel 120 at a second outlet 128 and deposits in an outlet annular cavity 102 located in the first end plate 45.

[0052] Figure 12A third channel 130 is depicted. A third inlet 131 draws fluid from an inlet annular cavity 101 located in the second end plate 46 and allows the fluid to flow through the third channel 130. The centrifugal force generated by the rotation of the rotor 40 and the pressure accumulated within the inlet annular cavity 101 force the fluid to flow through multiple third inner channels 132 and multiple third inner channel connectors 133. Centrifugal force and atmospheric pressure generated by the third vent 135 force the fluid to flow through a third bridging connector 134 to multiple third outer channels 136 and multiple third outer channel connectors 137. The fluid exits the third channel 130 at a third outlet 138 and deposits in an outlet annular cavity 102 located in the second end plate 46.

[0053] Figure 13 A fourth channel 140 is depicted. A fourth inlet 141 draws fluid from an inlet annular cavity 101 located in the second end plate 46 and allows the fluid to flow through the fourth channel 140. The centrifugal force generated by the rotation of the rotor 40 and the pressure accumulated within the inlet annular cavity 101 force the fluid to flow through multiple fourth inner channels 142 and multiple fourth inner channel connectors 143. The centrifugal force and atmospheric pressure generated by the fourth vent 145 force the fluid to flow through a fourth bridging connector 144 to multiple fourth outer channels 146 and multiple fourth outer channel connectors 147. The fluid exits the fourth channel 140 at a fourth outlet 148 and deposits in an outlet annular cavity 102 located in the second end plate 46.

[0054] Figure 14 A flowchart depicting the flow of fluid through multiple channels 100 is provided. In this depiction, the fluid flow in the first channel 110 and the second channel 120 can be understood as cooling flow in the forward direction. The fluid flow in the third channel 130 and the fourth channel 140 can be understood as cooling flow in the reverse direction.

[0055] exist Figure 15The image depicts a first alternative embodiment of an IPM motor 300. The IPM motor 300 is similar to the IPM motor 10 and may include a rotor 310 having a shaft 311, a first end plate 312, a second end plate 313, a center plate 314, and a stator 320. Like the IPM motor 10, the center plate 314 of the IPM motor 300 may include multiple center plates. The IPM motor 300 is configured to route cooling fluid through the rotor 310 in a substantially different manner than that of the IPM motor 10. In the rotor 310, multiple channels are formed in the first end plate 312, the second end plate 313, and the center plate 314, and the fluid is distributed along a parallel path in each of the multiple channels, rather than along a single uninterrupted path as in the rotor 40. Fluid is delivered to the first end plate 312 and to the second end plate 313 in a similar manner to the first end plate, utilizing fluid nozzles 23 arranged in a similar configuration to those in the IPM motor 10 in the IPM motor 300. In the forward cooling path, fluid is collected in the forward inlet annular cavity 315 in the second end plate 313 until pressure builds up, and the fluid can flow through the forward inner channel 316 and the forward outer channel 317 provided in the center plate 314. The fluid flows to the forward outlet annular cavity 318 provided in the first end plate 312. Then, the fluid flows out of the first end plate 312 from the forward outlet annular cavity 318 and is thrown off onto the stator 320. In the reverse cooling path, fluid is collected in the reverse inlet annular cavity 331 in the first end plate 312 until pressure builds up, and the fluid can flow through the reverse inner channel 332 and the reverse outer channel 333 provided in the center plate 314. The fluid flows to the reverse outlet annular cavity 334 provided in the second end plate 313. Then, the fluid flows out of the second end plate 313 from the reverse outlet annular cavity 334 and is thrown off onto the stator 320.

[0056] exist Figure 16 A second alternative embodiment of an IPM motor 400 is depicted. The IPM motor 400 is similar to the IPM motor 300 and may include a rotor 410 having a shaft 411, a first end plate 412, a second end plate 413, a center plate 414, and a stator 420. Like the IPM motor 300, the center plate 414 of the IPM motor 400 may include multiple center plates. The IPM motor 400 is configured to route cooling fluid through the rotor 410 in substantially the same manner as the IPM motor 300. However, the IPM motor 400 presents an alternative method for delivering fluid to the rotor 410. The fluid is delivered through an inner bore 415 disposed within the shaft 411, near the central axis of rotation of the shaft 411, and extends from a second end of the shaft 411 to the inner bore end within the shaft 411. Multiple channels connect to the inner bore 415 and extend through the diameter of the shaft 411. Figure 16In the depiction, the forward channel 416 and the reverse channel 417 may include multiple channels, and the inner hole 415 may be connected to the forward main annular cavity 431 in the second end plate 413 and the reverse main annular cavity 439 in the first end plate 412. The forward main annular cavity 431 may be connected to the main fluid path 432 and the secondary annular cavity 433. The secondary annular cavity 433 may be connected to the inlet annular cavity 434 and the vent 435. The inlet annular cavity 434 is connected to the fluid channel 436, the outlet annular cavity 437, and the fluid outlet 438.

[0057] The IPM motor 400 provides a cooling system with a constant rotor inlet flow rate. In some IPM motors, rotor losses due to heat are greatest when the rotor 410 rotates at high speed, while stator losses due to heat are greatest when the rotor 410 rotates at low speed. The IPM motor 400 allows fluid to be delivered to the stator 420 or the rotor 410 as needed. For example, the fluid can be delivered to the rotor 410 (440) through an inner bore 415 in the shaft 411. The fluid can flow through the inner bore 415 and can be delivered to the forward main annular cavity 431 and the reverse main annular cavity 439 through the forward channel 416 (441) and the reverse channel 417 (442), respectively. The fluid can then flow into the main fluid path 432 and the secondary annular cavity 433. When the rotor 410 rotates at low speed, the fluid can accumulate in the secondary annular cavity 433 and flow out from the vent 435 (443), thereby delivering the fluid to the stator 420. As the rotor 410 rotates at high speed, the fluid can accumulate in the secondary annular cavity 433 and flow out from the inlet annular cavity 434. The fluid can then flow through the fluid passage 436 (444) into the outlet annular cavity 437 and out from the fluid outlet 438, thereby cooling the rotor 410. The fluid can then be delivered from the fluid outlet 438 to the stator 420, thereby providing additional cooling (445) to the stator 420.

[0058] exist Figure 17A third alternative embodiment of the IPM motor 500 is depicted. The IPM motor 500 is substantially similar to the IPM motor 400 and may include a rotor 510 and a stator 520, the rotor having a shaft 511. The only substantial difference between the IPM motor 500 and the IPM motor 400 lies in the shaft 511. In the shaft 511, an inner bore 515 extends through the entire shaft 511, from a second end to a first end 519. The IPM motor 500 is configured to connect to an output end at the first end, which requires fluid for lubrication and / or cooling. Similar to the shaft 41 of the IPM motor 10, the IPM motor 500 may include multiple splines at the first end 519 for meshing with gears at the output end. The shaft 511 may include a lubrication channel 518 near the first end 519. The lubrication channel 518 and the inner bore 515 are then configured such that the first end 519 of the shaft 511 can be connected to the output end. Fluid flowing through the inner bore 515 (540) can deliver fluid to the output end (560) at the first end 519, and through the lubrication channel 518 near the multiple splines (550).

[0059] Industry Applicability In practice, the teachings of this disclosure can be applied to many industries, including but not limited to electric motors, automobiles, industrial equipment, and household appliances. Although depicted and described in conjunction with IPM motors used in industrial environments, such teachings can also be applied to other machines, such as electric vehicles, industrial machines, household appliances, and other types of machinery known to those skilled in the art.

[0060] Figure 18 A visual representation of a method 600 for operating an IPM motor 10 is illustrated. In a first step 601, an IPM motor 10 is provided, the IPM motor including a stator 30 and a rotor 40 disposed within a housing 20. The rotor 40 has a shaft 41, a first end plate 45, a second end plate 46, and a center plate. The shaft has a first end 42 and a second end 43. The center plate may be formed from a plurality of center plates 70.

[0061] In the second step 602, the IPM motor 10 can transfer fluid from the collection tank 21 to the first end plate 45 and the second end plate 46 of the rotor 40. The IPM motor 10 can achieve this in one of two ways.

[0062] In steps 603 and 604, the fluid can be first injected using the fluid nozzle 23 into the inlet annular cavity 101 on each of the first end plate 45 and the second end plate 46 of the rotor 40. The fluid collects in the inlet annular cavity 101 in the first end plate 45 and the second end plate 46, wherein the inlet annular cavity 101 is connected to a plurality of channels 100 disposed within the first end plate 45, the plurality of center plates 70, and the second end plate 46. In step 605, fluid pressure builds up in the inlet annular cavity 101 and causes the fluid to flow through the plurality of channels 100. In step 606, the fluid flows from the plurality of channels 100 to the outlet annular cavity 102 disposed in each of the first end plate 45 and the second end plate 46. In step 607, the fluid collects in the outlet annular cavity 102, forming an outlet fluid dam within the outlet annular cavity 102. In the eighth step 608, the fluid accumulates in the outlet annular cavity 102, causing excess fluid from the outlet fluid dam to flow onto the stator 30 and eventually back to the collection tank 21.

[0063] Alternatively, in the ninth step 609, the fluid may flow through the shaft 411 of the rotor 410, as illustrated in the IPM motor 400. In the tenth step 610, the fluid may be delivered to the rotor 410 through the inner bore 415 in the shaft 411 and may flow through the inner bore 415, and may be delivered to the forward main annular cavity 431 and the reverse main annular cavity 439 through the forward channel 416 and the reverse channel 417, respectively. The fluid may then flow into the main fluid path 432 and the secondary annular cavity 433. As the rotor 410 rotates at high speed, the fluid may accumulate in the secondary annular cavity 433 and flow out from the inlet annular cavity 434. In the eleventh step 611, the fluid may then accumulate in the inlet annular cavity 434, thereby applying pressure to the fluid and causing it to flow through the fluid channel 436. In the twelfth step 612, the fluid can flow into the outlet annular cavity 437, thereby establishing a fluid dam within the outlet annular cavity 437 (in the thirteenth step 613), and flow from the fluid outlet 438 to the stator 420 (in the fourteenth step 614).

[0064] In yet another alternative embodiment, the rotor 510 of the IPM motor 500 may be connected to the output gear of another machine that may require additional fluid to lubricate and / or cool the output gear. In step 615, the rotor may deliver fluid from the inner bore 515 to the lubrication channel 518 and the first end 519 of the shaft 511 that is in direct contact with the output gear.

[0065] The method 600 for operating the IPM motor 10 describes the cooling operation of the IPM motor 10 in the main embodiment, and how the IPM motor 10 can be actively cooled during operation so as not to experience performance loss due to excessive heat. Higher continuous performance of the IPM motor 10 can extend its service life and reduce downtime. Additionally, the arrangement of multiple channels in a serpentine pattern allows for more efficient cooling operation of the IPM motor 10.

[0066] The IPM motor 10 is configured for high maintainability. Components of the rotor 40 can be configured to be secured using removable fasteners, allowing the rotor 40 to be disassembled and serviced. The IPM motor can also be adapted to other machinery that requires additional cooling from the IPM motor.

[0067] Clearly, this disclosure is to be exemplary and various changes can be made by adding, modifying, or removing details without departing from the fair scope of the teachings contained herein. Therefore, the invention is not limited to the specific details of this disclosure unless so defined by the following claims.

Claims

1. A built-in permanent magnet motor, the built-in permanent magnet motor comprising: A housing, the housing including a liquid collection tank and a fluid transfer system configured to transfer fluid from the liquid collection tank to other parts of the housing; The rotor includes a shaft having a first end, a second end, and an intermediate section, and the rotor further includes: A first end plate, a second end plate, and a center plate are provided. The first end plate and the second end plate are disposed on the middle section of the shaft near the first end and the second end, respectively. The center plate is disposed on the middle section between the first end plate and the second end plate. Multiple magnets are disposed within multiple magnet slots arranged circumferentially within the central plate. Multiple channels are formed within the first end plate, the center plate, and the second end plate. The multiple channels extend back and forth within the rotor and are configured to allow fluid to flow in from the multiple channel inlets, through the multiple channels within the rotor, and out from the multiple channel outlets. and A stator, which is disposed within the housing surrounding the rotor and configured to receive electrical power and drive the rotor to rotate.

2. The built-in permanent magnet motor of claim 1, wherein the fluid delivery system further comprises a plurality of nozzles disposed within the housing and configured to inject the fluid into the plurality of channel inlets.

3. The built-in permanent magnet motor according to claim 2, wherein the first end plate and the second end plate further include: An inlet annular cavity is disposed on an outer surface and connected to the plurality of channel inlets. The inlet annular cavity is configured to receive jet fluid from the plurality of nozzles and collect the fluid, such that fluid pressure accumulates within the inlet annular cavity and the fluid flows through the plurality of channels. and An outlet annular cavity is disposed on the outer surface and connected to the plurality of channel outlets. The outlet annular cavity is configured to collect the fluid, such that an outlet fluid dam is formed within the outlet annular cavity until an excess of fluid accumulates, the excess fluid flowing out from the rotor to the stator.

4. The built-in permanent magnet motor according to claim 1, wherein the fluid is lubricating oil.

5. The built-in permanent magnet motor according to claim 1, wherein the center plate comprises a plurality of center plates forming a plurality of layers.

6. The built-in permanent magnet motor according to claim 3, wherein the plurality of channels further comprises: Multiple inner channels and multiple outer channels are disposed in the center plate, with the multiple inner channels disposed near the center portion of the center plate and the multiple outer channels disposed near the outer circumference portion of the center plate; Multiple inner channel connectors are disposed in the first end plate and the second end plate, and are used to connect adjacent inner channels among the multiple inner channels; Multiple external channel connectors are disposed in the first end plate and the second end plate, and are used to connect adjacent external channels among the multiple external channels; and A bridging connector that connects one of the plurality of inner channels to one of the plurality of outer channels; The plurality of channels thus form an uninterrupted channel, which flows from the entrance of the plurality of channels through the plurality of inner channels connected by the plurality of inner channel connectors, through the bridging connector to the plurality of outer channels connected by the plurality of outer channel connectors, and out through the outlet of the plurality of channels.

7. The built-in permanent magnet motor according to claim 6, wherein the plurality of channels further includes a plurality of vent pipes disposed in the first end plate or the second end plate, and the plurality of vent pipes are configured to connect the plurality of channels to an opening in the first end plate or the second end plate near the center portion of the first end plate or the second end plate.

8. A method for operating a built-in permanent magnet motor, the method comprising: The built-in permanent magnet motor is provided, the built-in permanent magnet motor includes a stator and a rotor disposed in a housing, the rotor having a shaft, a first end plate, a second end plate and a center plate, the shaft having a first end and a second end; Fluid is transferred from the liquid collection tank of the built-in permanent magnet motor to the first end plate and the second end plate of the rotor; The fluid is collected in the inlet annular cavity in the first end plate and the second end plate. The inlet annular cavity is connected to a plurality of channels disposed in the first end plate, the center plate and the second end plate, such that fluid pressure accumulates in the inlet annular cavity and the fluid flows through the plurality of channels. The fluid is collected in the outlet annular cavity provided in the first end plate and the second end plate, so that an outlet fluid dam is formed in the outlet annular cavity; as well as Excess fluid is allowed to flow from the outlet fluid dam to the stator and then back to the collection tank.

9. The method of claim 8, wherein the fluid is oil, and the oil is configured to lubricate and / or cool the rotor, the stator, and the housing of the built-in permanent magnet motor.

10. The method of claim 8, wherein transferring the fluid from the collection tank to the rotor further comprises: The fluid is transferred from the collection tank to a plurality of nozzles arranged circumferentially around the rotor within the housing; as well as The fluid from the plurality of nozzles is injected into the inlet annular cavity, which is disposed on the outer surfaces of the first end plate and the second end plate.

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