Method of manufacturing composite stator sleeve

Abstract

A method of manufacturing a stator sleeve first winds a cylindrical mandrel with a heated prepreg tape for automated fiber placement. The prepreg tape has a continuous fiber reinforcement material within a polymer matrix. Next, the cylindrical mandrel is cooled and removed from the wound prepreg tape, resulting in a cylindrical unfinished stator sleeve. Each end of the uncompleted stator sleeve is trimmed. Next, the first end ring and the second end ring are abutted against the first end and the second end of the trimmed stator sleeve, respectively, using a cylindrical fixing tool. The first end ring and the second end ring are of the same material as the polymer matrix of the prepreg tape. Finally, the first end ring and the second end ring are laser welded or melt bonded to the first end and the second end of the trimmed stator sleeve.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This non-provisional application claims priority to provisional application 63 / 365,308, filed on May 25, 2022, the entire contents of which are fully incorporated herein by these references. Technical Field

[0003] The present invention generally relates to stator sleeves for use in electric machines. More particularly, the present invention relates to methods of making composite stator sleeves for use in high performance electric machines having liquid cooled stators. Background Art

[0004] Generally speaking, electric motors have several key components that enable them to efficiently and effectively convert electrical energy into mechanical energy. Each component contributes to the critical interaction between the magnetic field that drives the motor and the current in the motor's windings, which creates force in the form of shaft rotation. It is the mechanical energy generated by this shaft rotation that helps keep an electric vehicle or factory operation running smoothly. These components can include the rotor, stator, support structure, windings, and air gap.

[0005] Rotor: The rotor is the moving part of the motor. The rotor turns the shaft, which transmits the aforementioned mechanical power. In a typical configuration, the rotor has conductors laid out in it, which carry an electric current, which then interacts with the magnetic field of the stator to create a force that turns the shaft. That being said, some rotors carry permanent magnets, while the stator holds the conductors.

[0006] Stator and stator core: The stator is the fixed part of the motor's electromagnetic circuit and usually includes windings or permanent magnets. The stator core is made up of many thin metal sheets, called laminates. The laminates are used to reduce energy losses that occur when using a solid iron core.

[0007] Support Structures: The rotor in an electric motor is supported by support structures that allow the rotor to rotate about the rotor axis. These support structures are in turn supported by the motor housing. The motor shaft extends through the support structures to the outside of the motor, where the load is applied. Since the force of the load is applied outside the outermost support structures, the load is said to be "overhanging".

[0008] Windings: Windings are wires laid out in coils, usually around a laminated soft iron core, to form magnetic poles when energized with an electric current. There are two basic field pole configurations for electric motors: salient and non-salient. In a salient pole motor, the magnetic field of the pole is created by windings around the poles underneath the pole face. In a non-salient pole motor, the windings are distributed in the pole face slots.

[0009] Air gap: Although not a physical component, the air gap is the distance between the rotor and the stator. The air gap of the motor has an important impact and is generally kept as small as possible, as a large air gap has a strong negative impact on performance. It is the main reason why the motor runs with a low power factor. Since the magnetizing current increases with increasing air gap, the air gap should be minimized. Having said that, very small gaps can cause problems with mechanical interference.

[0010] High performance electric motors can generate a lot of heat, especially in the conductors. Therefore, many high performance electric motors are configured with the rotor carrying permanent magnets and the stator holding the conductors. Liquid cooling can then be used to directly cool the conductors, resulting in a liquid cooled stator. A stator sleeve can be used to separate the stator from the rotor, enabling the use of a fluid coolant. Such liquid cooled motors can be used in applications such as electric vehicles, where high efficiency and power to weight ratio are important. Applicable inner rotor / outer stator motors include, but are not limited to, induction motors (IM), embedded permanent magnet motors (IPM), synchronous reluctance motors (SynRM), and embedded permanent magnet-synchronous reluctance motors (IPM-SynRM). In addition, outer rotor / inner stator motors (e.g., wheel hub motors) can benefit from the present invention.

[0011] Stator sleeves are known in the prior art. For example, US2003 / 0193260 teaches a powdered metal stator sleeve. Metal stator sleeves are not ideal due to their electrical conductivity and the eddy current losses that reduce the efficiency of the motor.

[0012] US 8,378,550 B2 teaches a stator sleeve that is located outside the stator windings, rather than between the stator and rotor as in the present invention. This coolant approach is not as effective as immersing the stator windings in coolant as in the present invention.

[0013] Application DE102020119110A1 teaches a stator sleeve which attempts to solve the cooling problem of high performance electric machines. However, as discussed further below, the present application improves on this teaching in a number of ways.

[0014] The purpose of a stator sleeve is to create a barrier between the stator and the rotor in an electric machine to allow coolant to flow through the stator for cooling, thereby improving the efficiency of the electric machine. Therefore, there is a need for an improved stator sleeve to enable an improved high performance electric machine. The present invention meets these needs and provides other related advantages. Summary of the invention

[0015] An exemplary embodiment of the present invention is a method for manufacturing a stator sleeve, wherein the stator sleeve is configured to be assembled as part of a cooled electric machine, the cooled electric machine having a stator and a rotor, the stator having a fixed conductor with a winding, the rotor having a rotating permanent magnet, and wherein a coolant liquid is configured to be able to cool the fixed conductor with the winding. The method for manufacturing the stator sleeve includes the following steps: providing a cylindrical mandrel; winding the cylindrical mandrel with a prepreg tape using an automated fiber placement, the automated fiber placement being in-situ consolidation, wherein the prepreg tape includes a continuous fiber reinforcement material within a polymer matrix; heating the prepreg tape during the automated fiber placement; cooling the wound prepreg tape by waiting for an elapsed time; removing the cylindrical mandrel from the wound prepreg tape to obtain a cylindrical unfinished stator sleeve; trimming each end of the unfinished stator sleeve to obtain a trimmed stator sleeve, the trimmed stator sleeve having a first end and an opposite end; the second end of the stator sleeve; providing a first end ring and a second end ring, wherein the first end ring and the second end ring both include a polymer, wherein the polymer of the first end ring and the second end ring is the same material as the polymer matrix of the prepreg tape; using a cylindrical fixing tool to abut the first end ring and the second end ring against the first end and the second end of the trimmed stator sleeve, respectively; and laser welding or melt-bonding the first end ring and the second end ring to the first end and the second end of the trimmed stator sleeve, respectively, thereby forming a completed stator sleeve, wherein the completed stator sleeve is configured to be installed in a cooling motor.

[0016] Alternative embodiments are now described. The prepreg tape winding of the continuous fiber reinforcement material can be a toroidal winding orientation. The continuous fiber reinforcement material can include S2 glass, IM7 carbon and / or boron. The polymer matrix can include PA, PET, PBT, POM, PPS, PEEK, PAEK and / or PEKK.

[0017] Heating of the prepreg tape during automated fiber placement may include hot air torch convection heating, laser heating, flash lamp heating, or infrared heating.

[0018] The first end ring and the second end ring may include a carbon black filled polymer.

[0019] The stator sleeve may be impermeable to the coolant liquid.

[0020] The prepreg tape may be unidirectional.

[0021] The step of removing the cylindrical mandrel from the wound prepreg tape may include cooling the cylindrical mandrel to cause it to shrink and reduce in size. Cooling the cylindrical mandrel may include flowing a cooling liquid through the cylindrical mandrel.

[0022] The step of removing the cylindrical mandrel from the wound prepreg tape may include dissolving the cylindrical mandrel in a liquid configured to dissolve a material of the cylindrical mandrel.

[0023] The step of removing the cylindrical mandrel from the wound prepreg tape may include disintegrating the cylindrical mandrel.

[0024] An exemplary embodiment of the present invention is a method of manufacturing a stator sleeve, wherein the stator sleeve is configured to be assembled as part of a cooled electric machine, the cooled electric machine having a stator and a rotor, the stator having a stationary conductor with a winding, the rotor having a rotating permanent magnet, and wherein a coolant liquid is configured to be able to cool the stationary conductor with the winding. The method for manufacturing a stator sleeve comprises the following steps: providing a cylindrical mandrel; winding the cylindrical mandrel with a prepreg tape using automated fiber placement; wherein the prepreg tape comprises a continuous fiber reinforcement material within a polymer matrix; heating the prepreg tape during automated fiber placement; cooling the wound prepreg tape by waiting for an elapsed time; removing the cylindrical mandrel from the wound prepreg tape to obtain a cylindrical unfinished stator sleeve, wherein the cylindrical unfinished stator sleeve is not fully consolidated; providing an outer mold, the outer mold defining an outer surface of a completed stator sleeve; placing the cylindrical unfinished stator sleeve; inserting a deformable bladder into the composite sleeve; pressurizing the deformable bladder; heating an assembly comprising the outer mold, the cylindrical unfinished stator sleeve and the deformable bladder, wherein the unfinished stator sleeve is fully consolidated, An unfinished stator sleeve is obtained; the assembly is cooled; the unfinished stator sleeve is removed from the outer mold and the deformable bag is removed; each end of the unfinished stator sleeve is trimmed to obtain a trimmed stator sleeve having a first end and an opposite second end; a first end ring and a second end ring are provided, wherein the first end ring and the second end ring both include a polymer, wherein the polymer of the first end ring and the second end ring is the same material as the polymer matrix of the prepreg tape; the first end ring and the second end ring are respectively pressed against the first end and the second end of the trimmed stator sleeve using a cylindrical fixing tool; and the first end ring and the second end ring are respectively laser welded or melt-bonded to the first end and the second end of the trimmed stator sleeve to form a completed stator sleeve, wherein the completed stator sleeve is configured to be installed in a cooling motor.

[0025] Other features and advantages of the present invention will become apparent from the following more detailed description, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The accompanying drawings illustrate the invention. In these drawings:

[0027] Figure 1 A cross-sectional view of the motor is shown;

[0028] Figure 2A It is a diagram of the in-situ consolidation (ISC) process;

[0029] Figure 2B is with Figure 2AA simplified side view similar to the illustration of , showing the in-situ consolidation process;

[0030] Figure 3 is an embodiment of a cylindrical sleeve removed from a cylindrical mandrel;

[0031] Figure 4A A grooved compaction roller is shown;

[0032] Figure 4B Axial features added to the stator sleeve are shown;

[0033] Figure 5A A first end ring of a stator sleeve is shown;

[0034] Figure 5B A second end ring of the stator sleeve is shown;

[0035] Fig. 6A It shows Figure 5A An enlarged cross-sectional view of a structure attached to one end of a stator sleeve;

[0036] Figure 6B It shows Figure 5B An enlarged cross-sectional view of a structure attached to the other end of the stator sleeve;

[0037] Figure 7 is an isometric view showing the use of a cylindrical fixing tool to position the end ring relative to the stator sleeve;

[0038] Figure 8 yes Figure 7 A front view of the structure, now with a laser welding machine applying laser energy to the end fittings and stator sleeve;

[0039] Fig. 9 yes Figure 8 Side view of

[0040] Fig.10 is an isometric view of a completed stator sleeve of the present invention;

[0041] Fig.11 It is a simplified representation of another innovative method of the present invention utilizing bladder forming;

[0042] Fig.12 is a perspective view of a simplified pouch mold of the present invention;

[0043] Fig.13 Shows Fig.12 the mold in which the sleeve and bladder are now inserted;

[0044] Fig.14 Shows Fig.13 A structure in which the pouch mold is pressurized and heated;

[0045] Fig.15 Shows Fig.14 cooling and decompression of structures; and

[0046] Fig.16 The resulting sleeve is shown, which may be trimmed and attached to the end ring as previously described herein. DETAILED DESCRIPTION

[0047] Composites have been progressively adopted into commercial aircraft. At each stage, composites have demonstrated their ability to form more and more flight-critical components with the required strength, stiffness, and near-freedom from defects (surface porosity as well as invisible internal voids) that could be a source of future damage as the aircraft ages. Until recently, this near-void-free standard (<1% porosity) was maintained by vacuum bag consolidation combined with exposure to high temperatures and pressures in an autoclave, typically for several hours during the curing process. In recent years, the development of oven-cured resins (systems that can be cured to acceptable void contents without an autoclave) has helped shorten cure cycles and, because ovens cost less to operate than autoclaves, can reduce the time and expense required to produce parts. At the same time, automated filament winding, automated tape laying (ATL), and automated fiber placement (AFP) equipment have replaced manual layup in many applications, dramatically increasing the speed of part layup. Although these systems are equipped with rollers that compact the material immediately after layup to ensure adhesion and avoid the formation of air pockets that can cause voids, consolidation of the laminated material still typically occurs in the second step of those two-step processes, under a vacuum bag, in an autoclave, oven or other heating device (e.g., a heat tool). This state of the art still exists, at least in part, because today's certified aerospace composites are primarily based on thermosets.

[0048] There is an alternative approach. It is called in-situ consolidation, meaning, consolidated in place. The key is to use a thermoplastic matrix instead of a thermoset matrix. Thermoplastic materials are liquid when heated to the melting temperature and solidify when cooled, but do not need to cross-link like thermosets. Consolidation of thermoplastic composites (TPCs) can then be achieved by quickly heating the impregnated reinforcement material to the melting temperature of the thermoplastic polymer matrix and then applying pressure when laying the tapes or tows onto the tool and / or previously laid layup. True in-situ consolidation (ISC) is a one-step process (no further heating or pressure steps are required after fiber placement or tape laying is completed).

[0049] The impact of eliminating an entire expensive step in the manufacturing process is so significant and obvious that one might ask, why isn’t everyone doing it already? One reason (and there are others, which will be discussed) is that change is expensive in the aerospace industry. Substitution of materials inevitably requires extensive and expensive testing and requalification.

[0050] That being said, two-step consolidation TPCs are already being used in select aircraft applications. Although their processing temperatures are much higher than thermosets (nearly 400°C versus 180°C / 350°F for primary structures), their cycle times are much shorter because TPCs only need to cool and not crosslink. Thermoplastics are also inherently tough and do not require special formulations to provide the fatigue resistance necessary for aircraft applications. In addition, because thermoplastics can be reheated and reshaped, they can be welded (a cost-saving, fastener-free assembly option). As the aircraft industry pursues materials and processing options that can achieve production rates of at least 60 aircraft / month and support the digital manufacturing, multifunctional structures and sustainability that are considered essential for next-generation aircraft, TPCs have become the frontrunners. TPCs have been the material of choice in most of the recently completed large-scale aircraft demonstration projects.

[0051] The inventors of the present invention have extensive experience in the aerospace industry and understand that automation of the manufacturing process for thermoplastics through automated tape placement (ATP) can increase productivity, reduce labor costs, and improve geometric feature repeatability compared to traditional hand layup. The inventors now turn their attention to improving electric motors that are widely used in high-performance applications.

[0052] The present invention improves upon the prior art by: incorporating end features for ease of connection to the stator, fluid sealing, and ease of assembly; optionally incorporating axial features on the outer diameter for ease of assembly, coolant flow channels, stator winding spacers, and reinforcement members; utilizing thermoplastic polymer composites to hold the entire structure together, providing excellent coolant / solvent resistance, allowing high rate manufacturing, allowing for recycling at the end of life; providing innovative manufacturing methods to facilitate manufacturing of optimized stator sleeves; and efficiently manufacturing complex stator sleeve assemblies at high rates.

[0053] As mentioned previously, the purpose of the stator sleeve is to create a barrier between the stator and the rotor in the electric machine to allow coolant to flow through the stator for cooling. Figure 1 The general configuration is shown as an enlarged cross-sectional view of an interior permanent magnet motor (IPM). Figure 1A cross-sectional view of an electric machine 10 is shown having a housing 11, a stator 12, windings 13, a rotor 14, a rotor sleeve 15, a stator sleeve 16 and permanent magnets 17. It will be appreciated that some electric machines may include a stator sleeve but not a rotor sleeve.

[0054] The stator sleeve 16 of the present invention is ideally made with thin walls. This results in a smaller gap between the stator and the rotor, thereby improving efficiency. The stator sleeve has high strength and stiffness. This allows for thinner walls and minimal deformation of the sleeve during use. The stator sleeve is not permeable to coolant, so fluid leakage through the material of the stator sleeve is not a problem. The stator sleeve has low magnetic permeability so that it does not interfere with the magnetic field between the rotor and the stator. The stator sleeve also has low electrical conductivity, which results in low electrical losses due to eddy currents. The stator sleeve combines the following features, such as: end fittings for connecting to the stator and for sealing purposes; structures for coolant flow channels, reinforcement, integration with stator windings, etc.; and mounting structures for easy assembly, alignment, etc.

[0055] Those skilled in the art who read the present disclosure will appreciate that the liquid permeability of the stator of the present invention is zero, because any leakage of the coolant will cause motor failure.

[0056] In addition, the carbon fiber, glass fiber and / or polymer composites of the present invention do not induce magnetic losses in the motor. More specifically, glass fibers (e.g., S2 glass) are excellent electrical insulators as are polymers and do not induce electrical losses in the motor. Carbon fibers are conductive along the length of the fiber (approximately 2 to 20 micro-ohm-meters). However, the continuous carbon fiber composites used in the present invention are insulated from each other by the polymer matrix, thereby resulting in a conductive path without eddy current losses.

[0057] The present invention relates to innovative materials and manufacturing methods to improve existing stator sleeves. The basic approach is to use advanced thermoplastic composite materials accompanied by innovative manufacturing methods to manufacture improved stator structures.

[0058] The general method of the invention is to first manufacture the pipe body using a process such as automated fiber placement (AFP) (which may be in-situ consolidation (ISC)) to produce a structure for a cylindrical sleeve. Any additional features such as end fittings and / or axial structures may then be incorporated.

[0059] The present invention starts with making a composite sleeve. Continuous fiber reinforcement materials can be used, such as S2 glass, IM7 carbon, boron or any other suitable fiber. Continuous fibers with higher strength and stiffness are preferred. A polymer matrix is ​​used to maintain the position of the fiber in the stator sleeve, protect the fiber, transfer structural loads between the fibers, and prevent the penetration of coolants. Due to the ability of thermoplastic polymers to be thermally combined with other features, coolant resistance and recyclability, thermoplastic polymers are preferred. Depending on the use temperature and other factors, suitable polymers include but are not limited to PA, PET, PBT, POM, PPS, PEEK, PAEK, PEKK.

[0060] Figure 2A is a picture of the in-situ consolidation (ISC) process. Figure 2B is with Figure 2A A simplified side view similar to the illustration of , showing the in-situ consolidation process. The incoming tape 20 is first directed between one or more tape supply rollers 21. The tape is ultimately laid onto a tool 22 on which a plurality of layers 23 are arranged. As the tape is directed through the supply rollers, it is ultimately directed onto the tool or previous layer by rollers 24, which apply a force 25 forcing the tape to be directed onto the tool or previous layer. The direction of travel is indicated by arrows 26. This means that either the tool moves in one direction or the rollers move in another direction, or a combination of both. A hot air torch convection heater 27 is used to heat the prepreg tape 20. Once enough layers have been laid, a tape cutter 28 can cut the tape.

[0061] Using the prior art of AFP and ISC, reinforced thermoplastic composite materials (such as but not limited to S2 / PEEK) are used to manufacture composite barrels. For high compressive strength, unidirectional composite prepreg tapes and a predominantly annular winding orientation are preferred. This means that the continuous length of fiber is around the circumference of the barrel. Figure 2A The ISC process is shown, which makes a barrel, Figure 2B A diagram of the process is shown in . The diagram shows a hot gas torch (HGT) heating technique, however lasers, flash lamps, infrared (IR) heaters or other suitable heating methods may also be used.

[0062] After the composite cylinder is consolidated, it is removed from the mandrel and trimmed to the desired length. The mandrel can be cooled to facilitate removal of the composite sleeve from the mandrel, and such cooling can be integrated into the mandrel using, for example, a refrigerant. It is worth noting that ISC processing generally does not require a mold release agent, unlike consolidation in which the mandrel is heated with the part in an autoclave. The mandrel never reaches the polymer melt temperature, preventing bonding. In the inventor's experience, inexpensive aluminum mandrels are preferred due to the high coefficient of thermal expansion (CTE), which facilitates removal of the part after cooling.

[0063] Figure 3 is an embodiment of a cylindrical sleeve 18 removed from a cylindrical mandrel 22 .

[0064] Similarly, a disintegrating or soluble mandrel may be used. A disintegrating or soluble mandrel may be used, but is generally not required for the ISC process. In cases where removal is not otherwise possible, PLA (polylactic acid), eutectic salts, or any other suitable soluble mandrel may be used.

[0065] Alternatively, braiding, 3D braiding, knitting or other textile processes may be used to make an unconsolidated sleeve preform. Vacuum bags, shrink wrap tape or other suitable methods may be used to consolidate the sleeve preform instead of the ISC process. However, braiding or other textile weaving processes reduce the compressive strength of the composite cylinder due to the fiber fluctuations necessitating thicker laminate materials.

[0066] Figure 4A A slotted compacting roller 30 is shown. The slotted compacting roller is used to form the axial ribs 40. The slotted compacting roller rolls in the longitudinal direction of the sleeve 18, where the curvature 31 matches the outer diameter of the sleeve. There is an annular gap 32 that forms the axial ribs 40. In other words, the axial ribs 40 on the outer diameter of the stator sleeve 18 are formed using an in-situ process, where the neat polymer is melted onto the outer diameter of the sleeve, and the roller will form a square cross-sectional profile with the annular gap 32. Heat is applied to the neat material and the outer diameter of the stator sleeve to melt them together. The roller also applies the required compaction force to push the neat material onto the sleeve to achieve intimate contact for molecular chain entanglement.

[0067] Figure 4B It is shown that axial features 40 (eg, stator slots) may be added using grooved or otherwise shaped recesses in the compaction rollers in conjunction with additional composite or polymer filaments using the ISC process.

[0068] Alternatively, features may be added using an additive manufacturing process such as fused filament fabrication (FFF). These features may be added using continuous fiber composites, chopped fiber fill, or pure polymer filaments.

[0069] In addition, the stator slots may be filled with an insulator (e.g., a PEEK polymer insert) for electrical insulation. Such slot fillers may advantageously be incorporated into the stator sleeve for the added benefit of greater bending stiffness.

[0070] A trimming operation may be required to trim each end of the unfinished stator sleeve 18 , resulting in a trimmed stator sleeve having a first end 18 a and an opposing second end 18 b .

[0071] To complete the production of a ready stator sleeve, the end of the stator must be configured to work within a specific motor. This means that a variety of features and structures are required along the end of the stator sleeve. In the present invention, end rings or other features can be added by fusion bonding or other methods. Figure 5A and Figure 5B Two exemplary end rings 51 and 52 are shown which may be attached to the stator sleeve.

[0072] Fig. 6A is an enlarged cross-sectional view showing Figure 5A The structure (end ring 51) is attached to one end 18a of the stator sleeve 18. Similarly, Figure 6B is also an enlarged cross-sectional view showing Figure 5B The structure (end ring 52) is attached to the other end 18b of the stator sleeve 18. The overlap of the stator sleeve 18 and the end fitting can be seen.

[0073] Figure 7 The use of a cylindrical fixing tool 60 to position the end rings 51, 52 relative to the stator sleeve 18 is now shown. The fixing tool helps to align and hold the end rings relative to the stator sleeve. For example, the tool 60 has a larger diameter portion 61 that abuts against the end ring 51 when the end ring 51 is first slid on. Next, the stator sleeve can be slid on. Finally, the end ring 52 can be slid onto the tool 60. In this way, all three components are held together in an abutting relationship. Subsequently, as shown, a laser welder 70 or other equipment can be used to join the end rings to the sleeve.

[0074] Figure 8 yes Figure 7 , laser energy 71 is now applied to the end fitting and stator sleeve using a laser welding machine 70. It can be seen that laser energy 71 is applied to the stator sleeve 18 and the end ring 52 and permanently connects them together.

[0075] Fig. 9 Shown as Figure 8 . A laser beam 71 is shown directed toward the end fitting and roller 72. Roller 72 helps facilitate the connection of the end ring and the stator sleeve. The roller applies compaction pressure to the sleeve and end ring. In order to melt the plastic material together, heat and pressure need to be applied. The laser energy melts the surface and the roller applies the pressure required to bond the two parts together. It will be appreciated by those skilled in the art that other techniques can also be used to permanently connect the end ring to the stator sleeve, such as melt bonding or friction welding.

[0076] exist Figure 8 and Fig. 9In the example, the stator sleeve typically has a tan color, representing the natural color of the S2 / PEEK composite, while the end fittings are darker (e.g., black), indicating that the PEEK is filled with IR absorbing materials (e.g., carbon black). The S2 / PEEK is transparent to the IR laser, while the carbon black-filled PEEK absorbs the IR laser energy, thereby heating the carbon black-filled PEEK surface, enabling it to melt bond to the S2 / PEEK sleeve.

[0077] Fig.10 The completed stator sleeve assembly 16 is shown. One advantage of the present invention is that the polymer used to make the end rings and the polymer used in the polymer matrix of the prepreg tape can be the same material. This allows for a good connection between the stator sleeve and the end rings, whether they are laser welded or melt bonded.

[0078] Fig.11 An alternative form of manufacturing the stator sleeve of the present invention using pocket forming is shown.

[0079] The bladder is an alternative consolidation method. The idea is to start with a composite sleeve 80 that does not need to be fully consolidated. Such a sleeve can be, for example, a partial ISC (in-situ consolidated) sleeve or a braided sleeve.

[0080] The manufacturing process may include the following steps. First, a composite sleeve preform 80 is manufactured. Step A shows the insertion of a deformable bladder 81 into the composite sleeve 80. The sleeve and bladder are then inserted into molds 82, 83. Step B shows the bladder being pressurized 84, forcing the sleeve to take the shape of the molds 82 and 83. Step C shows the assembly being heated 85 to above the melting temperature of the polymer. This heating will occur while pressurizing. The assembly is then cooled 86 and the consolidated part and bladder are removed from the mold, as shown in step D. Although Fig.11 The shape is a simple cavity for illustration only, but those skilled in the art will appreciate that the shape may be a cylinder or any other shape.

[0081] Figure 12-16 is a better description Fig.11 A perspective view of the process described in . Fig.12 82 and 83. It is a two-part mold, but can include any number of parts and sections. The inside of the mold defines a surface 87, which ultimately defines the outer surface of the sleeve 80 after the pressure and heat are applied. Fig.13 The addition of a sleeve 80 and the insertion of a deformable bladder 81 within the sleeve are shown. Fig.14 The top mold 83 is shown added, and then the deformable bladder 81 is pressurized 84 and heated 85. After sufficient time to complete the formation of the sleeve, Fig.15 It is shown that the assembly can be cooled 86 and the bladder 81 can be depressurized. Fig.16It is shown that the top mold 83 can be removed, followed by the bladder 81. The sleeve 80 can then be removed. It should be understood that the sleeve 80 can then be trimmed and end rings added as previously described.

[0082] This approach has several advantages, which are now described. The internal pressure and resulting expansion tend to remove wrinkles from the fibers, thereby increasing compressive and tensile strength. The process fully consolidates the laminate, reduces porosity, and eliminates penetration. External features such as ribs, end rings, or other features can be formed as long as there is excess polymer or filled polymer.

[0083] Depending on temperature, expansion and other factors, the bladder can be made of different materials. The bladder can be made of an elastomer (such as silicone), a metal (such as aluminum), or a polymer with a higher melting point (such as polyimide).

[0084] The bladder can be energized in different ways. First, the bladder can be energized by internal pressure (e.g., by pneumatics or air pressure). Second, the bladder can be energized by applying a force (through the use of various structures, clamps, and / or weights). Third, the structure can be energized by utilizing a material with a higher coefficient of thermal expansion (CTE) than the surrounding structure.

[0085] For example, an air-pressurized silicone bladder can be used to bag mold a fiberglass / PA composite cylinder. Alternatively, a solid silicone cylinder can be used instead of the bladder, where the high CTE of the silicone (assuming the CTE of the mold is lower, such as steel) will apply pressure at the melting temperature of the PA. In the case of a fiberglass / PEEK cylinder, the silicone bladder will degrade at the higher temperatures (>343°C) required to melt PEEK, so a higher temperature bladder is required, such as a PI bladder or an aluminum bladder. Alternatively, a solid cylinder of aluminum can be used instead of the bladder, where the high CTE of the aluminum (assuming the CTE of the mold is lower, such as steel) will apply pressure at the melting temperature of the PEEK.

[0086] Although a number of embodiments have been described in detail for purposes of illustration, various modifications may be made to each embodiment without departing from the scope and spirit of the invention. Accordingly, the present invention is not to be limited except as by the appended claims.

[0087] Reference numerals list

[0088] 10 Motor

[0089] 11 Shell

[0090] 12 Stator

[0091] 13 Winding

[0092] 14 rotors

[0093] 15 Rotor sleeve

[0094] 16 stator sleeve

[0095] 17 permanent magnets

[0096] 18 Unfinished sleeve, unfinished stator

[0097] 20 tape, prepreg tape

[0098] 21 belt supply roller

[0099] 22 Tools, spindles

[0100] 23Single layer, multiple layers

[0101] 24 rollers

[0102] 25 Strength

[0103] 26 Direction of travel

[0104] 27 Heater, hot air torch convection heater

[0105] 28 with cutter

[0106] 30 slotted compaction roller

[0107] 31Curvature

[0108] 32 Annular gap

[0109] 40 Axial features / ribs, stator sleeve

[0110] 51 end ring, stator sleeve

[0111] 52 end ring, stator sleeve

[0112] 60 cylindrical fixing tool

[0113] 70 laser welding machine

[0114] 71 laser energy

[0115] 72 rollers

[0116] 80 composite sleeve prefabricated parts

[0117] 81 Deformable Capsule

[0118] 82 mold, bottom

[0119] 83 mold, top

[0120] 84 Pressurization

[0121] 85 Heating

[0122] 86 Cooling

[0123] 87 surface, inside of mold, outside of sleeve

Claims

1. A method of manufacturing a stator sleeve, the stator sleeve being configured to be assembled as part of a cooled electric machine, the cooled electric machine having a stator and a rotor, the stator having a fixed conductor with a winding, the rotor having a rotating permanent magnet, wherein a coolant liquid is configured to cool the fixed conductor with the winding, the method of manufacturing the stator sleeve comprising the following steps: providing a cylindrical mandrel; wrapping the cylindrical mandrel with prepreg tape using automated fiber placement, the automated fiber placement being in-situ consolidation; wherein the prepreg tape comprises a continuous fiber reinforcement within a polymer matrix; heating of prepreg tapes during automated fiber placement; Cooling the wound prepreg tape by waiting for the elapsed time; removing the cylindrical mandrel from the wound prepreg tape to obtain a cylindrical unfinished stator sleeve; trimming each end of the unfinished stator sleeve to obtain a trimmed stator sleeve, the trimmed stator sleeve having a first end and an opposite second end; providing a first end ring and a second end ring, wherein the first end ring and the second end ring each comprise a polymer; wherein the polymer of the first end ring and the second end ring is the same material as the polymer matrix of the prepreg tape; Using a cylindrical fixing tool, a first end ring and a second end ring are respectively pressed against the first end and the second end of the trimmed stator sleeve; and The first and second end rings are laser welded or fusion bonded to the first and second ends of the trimmed stator sleeve, respectively, thereby forming a completed stator sleeve configured for installation in a cooled electric machine.

2. The method according to claim 1, wherein: The prepreg tape of continuous fiber reinforcement is wound in a toroidal winding orientation.

3. The method according to claim 1 or 2, wherein: The continuous fiber reinforcement material includes S2 glass, IM7 carbon and / or boron.

4. A method according to any one of the preceding claims, wherein: The polymer matrix includes PA, PET, PBT, POM, PPS, PEEK, PAEK and / or PEKK.

5. A method according to any one of the preceding claims, wherein: Heating of the prepreg tape during the automated fiber placement includes hot air torch convection heating, laser heating, flash lamp heating, or infrared heating.

6. A method according to any one of the preceding claims, wherein: The first end ring and the second end ring include a carbon black filled polymer.

7. A method according to any one of the preceding claims, wherein: The stator sleeve is impermeable to the coolant liquid.

8. A method according to any one of the preceding claims, wherein: The prepreg tape is unidirectional.

9. A method according to any one of the preceding claims, wherein: The step of removing the cylindrical mandrel from the wound prepreg tape includes cooling the cylindrical mandrel to cause it to shrink and reduce in size.

10. The method according to claim 9, wherein: Cooling the cylindrical mandrel includes flowing a cooling liquid through the cylindrical mandrel.

11. A method according to any one of the preceding claims, wherein: The step of removing the cylindrical mandrel from the wound prepreg tape includes dissolving the cylindrical mandrel in a liquid configured to dissolve a material of the cylindrical mandrel.

12. A method according to any one of the preceding claims, wherein: The step of removing the cylindrical mandrel from the wound prepreg tape includes disintegrating the cylindrical mandrel.

13. A method of manufacturing a stator sleeve, the stator sleeve being configured to be assembled as part of a cooled electric machine having a stator and a rotor, the stator having a fixed conductor with a winding, the rotor having a rotating permanent magnet, wherein a coolant liquid is configured to cool the fixed conductor with the winding, the method of manufacturing the stator sleeve comprising the steps of: providing a cylindrical mandrel; wrapping the cylindrical mandrel with prepreg tape using automated fiber placement, the automated fiber placement being in-situ consolidation; wherein the prepreg tape comprises a continuous fiber reinforcement within a polymer matrix; wherein the prepreg tape of the continuous fiber reinforcement material is wound in a toroidal winding orientation; wherein the continuous fiber reinforcement material comprises S2 glass, IM7 carbon and / or boron; wherein the polymer matrix comprises PA, PET, PBT, POM, PPS, PEEK, PAEK and / or PEKK; heating the prepreg tape during automated fiber placement, wherein the heating comprises hot air torch convection heating, laser heating, flash lamp heating, or infrared heating; Cooling the wound prepreg tape by waiting for the elapsed time; removing the cylindrical mandrel from the wound prepreg tape to obtain a cylindrical unfinished stator sleeve; trimming each end of the unfinished stator sleeve to obtain a trimmed stator sleeve, the trimmed stator sleeve having a first end and an opposite second end; providing a first end ring and a second end ring, wherein the first end ring and the second end ring each comprise a polymer; wherein the first end ring and the second end ring comprise a carbon black filled polymer; wherein the polymer of the first end ring and the second end ring is the same material as the polymer matrix of the prepreg tape; Using a cylindrical fixing tool, placing a first end ring and a second end ring against the first end and the second end of the trimmed stator sleeve, respectively; as well as The first and second end rings are laser welded or fusion bonded to the first and second ends of the trimmed stator sleeve, respectively, thereby forming a completed stator sleeve configured for installation in a cooled electric machine.

14. A method of manufacturing a stator sleeve, the stator sleeve being configured to be assembled as part of a cooled electric machine having a stator and a rotor, the stator having a fixed conductor with a winding, the rotor having a rotating permanent magnet, wherein a coolant liquid is configured to cool the fixed conductor with the winding, the method of manufacturing the stator sleeve comprising the steps of: providing a cylindrical mandrel; wrapping the cylindrical mandrel with prepreg tape using automated fiber placement; wherein the prepreg tape comprises a continuous fiber reinforcement within a polymer matrix; heating the prepreg tape during said automated fiber placement; Cooling the wound prepreg tape by waiting for the elapsed time; removing the cylindrical mandrel from the wound prepreg tape to obtain a cylindrical unfinished stator sleeve; wherein the cylindrical unfinished stator sleeve is not fully consolidated; providing an outer mold that defines an outer surface of the finished sleeve; placing a cylindrical unfinished stator sleeve; inserting the deformable bladder into the composite sleeve; pressurizing the deformable bladder; heating an assembly including an outer mold, a cylindrical unfinished stator sleeve, and a deformable bladder, wherein the unfinished stator sleeve is fully consolidated to obtain an unfinished stator sleeve; cooling the assembly; removing the unfinished stator sleeve from the outer mold and removing the deformable bladder; trimming each end of the unfinished stator sleeve to obtain a trimmed stator sleeve having a first end and an opposite second end; providing a first end ring and a second end ring, wherein the first end ring and the second end ring each comprise a polymer; wherein the polymer of the first end ring and the second end ring is the same material as the polymer matrix of the prepreg tape; Using a cylindrical fixing tool, a first end ring and a second end ring are respectively pressed against the first end and the second end of the trimmed stator sleeve; and The first and second end rings are laser welded or fusion bonded to the first and second ends of the trimmed stator sleeve, respectively, thereby forming a completed stator sleeve configured for installation in a cooled electric machine.

15. The method according to claim 14, wherein: The prepreg tape of continuous fiber reinforcement is wound in a toroidal winding orientation.

16. The method according to claim 14 or 15, wherein: The continuous fiber reinforcement material includes S2 glass, IM7 carbon and / or boron.

17. The method according to any one of claims 14 to 16, wherein: The polymer matrix includes PA, PET, PBT, POM, PPS, PEEK, PAEK and / or PEKK.

18. The method according to any one of claims 14 to 17, wherein: Heating of the prepreg tape during the automated fiber placement includes hot air torch convection heating, laser heating, flash lamp heating, or infrared heating.

19. The method according to any one of claims 14 to 18, wherein: The first end ring and the second end ring include a carbon black filled polymer.

Images