CN112054608A

CN112054608A - Axial flux machine and method of assembling the same

Info

Publication number: CN112054608A
Application number: CN202010504486.8A
Authority: CN
Inventors: S·W·波斯特; L·D·库恩斯; J·J·朗
Original assignee: Rebecca America
Current assignee: Rebecca America
Priority date: 2019-06-07
Filing date: 2020-06-05
Publication date: 2020-12-08
Also published as: DE102020113725A1

Abstract

A stator assembly for an axial flux electric motor includes a plurality of circumferentially spaced tooth assemblies, each tooth assembly including a tooth portion and a base. The stator assembly also includes a plurality of circumferentially spaced bridge members, each bridge member configured to engage a pair of circumferentially adjacent bases.

Description

Axial flux machine and method of assembling the same

Cross Reference to Related Applications

The present application claims priority from U.S. partial continuation patent application No.16/435,041, filed on 7/6/2019, the entire disclosure of which is incorporated herein in its entirety.

Technical Field

The field of the invention relates generally to electric machines and more particularly to axial flux electric motors having modular stators.

Background

One of the many applications for electric motors is to operate pumps or blowers. The motor may be configured to rotate an impeller within the pump or blower that displaces fluid, thereby causing the fluid to flow. Many gas-fired appliances include electric motors, such as water heaters, boilers, pool heaters, warmers, stoves, and radiant heaters. In some examples, the electric motor powers a blower for moving air or a fuel/air mixture through the appliance. In other examples, the motor powers a blower for dispensing air output from the appliance.

In some known axial flux motors, the portion of the stator teeth with the tooth tips attached are attached to a U-shaped stator member, and the stator core, bobbin, and windings are overmolded with resin to secure the stator components together. However, overmolding the stator increases the manufacturing and labor costs of the motor and also limits the power generated by the motor due to the heat build up within the overmolded stator.

Another known axial flux motor includes a laminated system of pressed together, in which a pair of stator teeth are pressed into a single stator base. However, this configuration limits the motor type to a multiple pole motor of 10.

Disclosure of Invention

In one aspect, a stator assembly for an axial flux electric motor is provided. The stator assembly includes a plurality of circumferentially spaced tooth assemblies, each tooth assembly including a tooth portion and a base. The stator assembly also includes a plurality of circumferentially spaced bridge members, each bridge member configured to engage a pair of circumferentially adjacent bases.

In another aspect, an axial flux electric motor is provided. The axial flux motor includes a frame, a rotor assembly, and a stator assembly coupled to the frame and positioned adjacent the rotor assembly to define an axial gap therebetween. The stator assembly includes a plurality of circumferentially spaced tooth assemblies, each tooth assembly including a tooth portion and a base. The stator assembly also includes a plurality of circumferentially spaced bridge members, each bridge member configured to engage a pair of circumferentially adjacent bases.

In yet another aspect, a method of assembling an axial flux electric motor is provided. The method includes coupling a plurality of circumferentially spaced tooth assemblies to a frame. Each tooth assembly includes a base connected to the frame and a tooth extending axially from the base. The method also includes connecting a bridge member to a pair of circumferentially adjacent bases such that the bridge member extends between the circumferentially adjacent bases.

Drawings

FIG. 1 is a perspective view of one embodiment of an electric motor;

FIG. 2 is a perspective view of a stator assembly for the electric motor shown in FIG. 1;

FIG. 3 is a perspective view of another embodiment of an electric motor showing an alternative stator assembly;

FIG. 4 is a perspective view of another embodiment of a stator assembly;

FIG. 5 is a perspective view of a bridge ring for the stator assembly of FIG. 4;

FIG. 6 is a perspective view of an exemplary embodiment of an electric motor;

FIG. 7 is a cross-sectional view of the motor shown in FIG. 6;

FIG. 8 is a perspective view of an exemplary stator assembly for the motor shown in FIG. 6; and

fig. 9 is an exploded view of a portion of the stator assembly shown in fig. 8.

Detailed Description

Example methods and systems for an axial flux motor are described herein. The axial flux motor includes a stator assembly having a plurality of circumferentially spaced tooth assemblies, each tooth assembly including a tooth and a base integrally formed with the tooth. The stator assembly also includes a plurality of circumferentially spaced bridge members, each bridge member configured to engage a pair of circumferentially adjacent bases. The bridge member is coupled between circumferentially adjacent bases to apply an axial preload force to both bases and also to facilitate flux flow between adjacent bases. The laminations that make up the bridge member are oriented so that the direction of the magnetic flux does not generate eddy currents but still allows the lamination direction to form a structural member to hold the stator components in place. The mechanical bond between the base and the bridge member holds the stator assembly together without the need for overmolding the stator assembly with resin, thereby reducing cost and improving efficiency of the motor. The resulting configuration allows for custom motor sizes and relatively small motors for high speed applications.

Fig. 1 is a perspective view of the motor 108. Fig. 2 is a perspective view of a stator assembly 112 for the electric motor 108. In one embodiment, the electric motor 108 is an axial flux electric motor that includes a rotor assembly 110 and a stator assembly 112, the stator assembly 112 being coupled to the rotor assembly 110 to define an axial gap 114 therebetween. Rotor assembly 110 generally includes a rotor 116 and at least one permanent magnet 118 coupled to rotor 116. In one embodiment, the permanent magnet 118 is made of ferrite (ferrite) and is formed as a single disk with multiple poles. Alternatively, the permanent magnet 118 includes a plurality of magnet segments coupled to the rotor 116. In general, any suitable permanent magnet shape, number of segments, and material may be used that enables motor 108 to function as described herein. The rotor assembly 110 is rotatable within the motor housing 106 about an axis of rotation 120. In one embodiment, the motor 108 is energized by an electronic controller (not shown), for example, a sinusoidal or trapezoidal output electronic controller. In one embodiment, the rotor 116 is machined and/or cast from any suitable material (e.g., steel).

The stator assembly 112 is a multi-phase (more than one phase) axial flux stator, and is preferably a three-phase axial flux stator that generates magnetic flux in an axial direction (i.e., parallel to the axis of rotation 120). The stator assembly 112 includes a motor frame 122 coupled to the blower housing 102 and at least one base 424 coupled to the motor frame 122. In one embodiment, the stator assembly 112 includes a plurality of circumferentially spaced apart bases 124 coupled to the motor frame 122. The stator assembly 112 also includes a plurality of tooth assemblies 130, each tooth assembly 130 including a stator tooth 132 coupled to a tooth tip 134. Alternatively, tooth assembly 130 may include only stator teeth 132 and no tooth tips 134.

As described in further detail below, in one embodiment, each base 424 is coupled to at least one tooth assembly 130. As used herein, the term "coupled" is intended to describe mechanical joining of the individual components and also describes a configuration in which the components are integrally formed as a unitary member. For example, in one embodiment, base 124 and tooth assembly 130 are separately formed and coupled together by inserting at least one tooth assembly 130 into each base 424, as described below. In another embodiment, the base 124 and tooth assembly 130 are coupled together by integrally forming each base 124 with at least one tooth assembly 130 formed from a single laminate. In both configurations, each base 424 is "coupled" to at least one tooth assembly 130 by a mechanical lock engagement (positive mechanical joint) or by being integrally formed.

In one embodiment, each stator tooth 132 includes an insertable portion 136 and each base portion 424 includes at least one receiving slot 138, the receiving slots 138 configured to receive the insertable portions 136 to form a mechanical interface between the base portions 424 and the stator teeth 132. As used herein, the term "mechanical joint" refers to a portion of a machine in which one mechanical component is connected to another mechanical component. Specifically, the mechanical joint is formed by joining metal parts via a mechanical form-locking retaining assembly. More specifically, in one embodiment, mechanical interface 139 is an interference fit between base 424 and stator teeth 132, wherein the outer dimensions of one component slightly exceed the inner dimensions of the component in which it must fit. In this manner, the insertable portion 136 and receiving slot 138 hold the tooth assembly 130 and the base 424 together without the need to over mold the stator assembly 112 with resin, thereby reducing costs and increasing the efficiency of the motor 108.

In one embodiment, each base 424 includes a single receiving slot 138 and relief/unload slots (not shown). Further, the base 424 includes a strut (not shown) located between the relief groove and the receiving groove 138. In operation, when the insertable portion 136 of the stator teeth 132 is inserted into the receiving slot 138, the posts will deform slightly to accommodate the taper angle of the insertable portion 136, which will result in similar deformation of the relief groove. In this way, the retention forces on both sides of the insertable portion 136 are equal and the tooth assembly 130 maintains an orientation perpendicular to the base 424 and parallel to the axis 120.

As shown in fig. 2 and 3, in one embodiment, tooth tip 134 and stator teeth 132 are integrally formed as a unitary component. Alternatively, tooth tip 134 and stator teeth 132 are separate components coupled together. In another embodiment, tooth assembly 130 includes only stator teeth 132 and no tooth tips 134. In one embodiment, tooth assembly 130, having tooth tip 134 and stator teeth 132, is made from a plurality of stacked laminate sheets. This configuration simplifies the manufacturing process and enables the tooth assembly 130 to be produced quickly and efficiently. The stator teeth 132 have substantially the same width from the inner edge to the outer edge. This enables the laminate sheets from which the tooth assemblies 130 are constructed to be substantially identical, which reduces manufacturing costs. Similarly, the base 424 is also formed from a plurality of stacked laminate sheets. More specifically, each laminate sheet of the base 424 and tooth assembly 130 includes a pair of laminate interlocks that facilitate coupling a plurality of laminate sheets together to form the tooth assembly 130 or base 424 having a desired width. The laminate interlocking portion is formed as a recess on one side of the tooth assembly 130 and the base 424 and as a protrusion on the opposite side. In this way, the protrusion of one interlocking portion of a first sheet fits into the recess of another interlocking portion on an adjacent sheet.

In one embodiment, the stator assembly 112 further includes a plurality of circumferentially spaced bridge members 140, the bridge members 140 engaging a pair of circumferentially adjacent bases 124 to apply an axial preload force to the bases to hold the bases 124 in their desired positions and form a flux path between the adjacent bases 124. As best shown in fig. 2, the bridge member 140 is substantially trapezoidal in shape and includes a first axial surface 142, a second axial surface 144, a first circumferential end surface 146, and a second circumferential end surface 148. In one embodiment, each base 424 includes a pair of substantially similar end shoulders 150 defined by an axial surface 152 and a circumferential end surface 154, respectively. In operation, a single bridge member 140 engages an adjacent end shoulder 150 of a circumferentially adjacent base 124. More specifically, the second axial surface 144 of the bridge member 140 engages the shoulder axial surfaces 152 of two circumferentially adjacent end shoulders 150 to apply an axial force to the axial surfaces 152. In some embodiments, the first circumferential end surface 146 of each bridge member 140 engages with a respective shoulder circumferential end surface 154 of the first base 424, and the second circumferential end surface 148 of each bridge member 140 engages with a respective shoulder circumferential end surface 154 of the second base 424 that is circumferentially adjacent to the first base 424.

In one embodiment, the stator assembly 112 also includes a plurality of fasteners 156 that couple the bridge member 140 to the frame 122. More specifically, each bridge member 140 includes an opening 158 defined therethrough, the opening 158 receiving the fastener 156. As best shown in fig. 1, the fasteners 156 extend through the openings 158 and between the bridge members 140 and the frame 122 to secure the base 124 to the frame 122. As such, the fastener 156 exerts an axial force on the bridge member 140 that is transferred to the base 124 through the engagement of at least the

axial surfaces

144 and 152. In such a configuration, the base 124 spaces the bridge member 140 from the frame 122 to define a gap 160 therebetween. In one embodiment, the fastener 156 is a non-ferrous screw. In another embodiment, the fastener 156 is a rivet or a clamp. Generally, the fasteners 156 are any type of retention device that facilitates operation of the stator assembly 112 as described herein. In this way, the bridge member 140 applies an axial preload force to the base 424 and holds the stator assembly 112 together without the need for overmolding with resin, thereby reducing costs and increasing efficiency of the motor 108.

As best shown in fig. 1 and 2, the bridge member 140 is formed from a plurality of stacked laminations, similar to the tooth assembly 130 and the base 124. However, when the tooth assembly 130 and base 124 are formed from vertically oriented laminations, as described above, the bridge member 140 is formed from a plurality of horizontally oriented laminations. This difference in orientation between the base 124 and the bridge members 140 reduces the occurrence of eddy currents and enables magnetic flux to flow efficiently between the bases 124 because the horizontal laminations of the bridge members 140 are oriented in the same direction as the direction of the flow of magnetic flux exiting the bases 124. Additionally, in one embodiment, the stator assembly 112 includes a very thin insulating layer (not shown), such as, but not limited to, a sheet of material or a coated coating between the base 124 and the bridge member 140 to prevent stack shorting and further reduce eddy current formation.

As described herein, in one embodiment, the bridge member 140 both applies an axial preload force to the base 124 and also creates an effective magnetic flux path that reduces eddy current formation. In one embodiment, the bridge member 140 is used to apply only an axial preload force but not to promote flux flow. In such a configuration, the bridge member 140 may be formed of a material other than the stacked laminations and act as a clamp to secure the base 124 to the frame 122. Alternatively, in another embodiment, the bridge members 140 serve to promote only effective flux flow between adjacent bases 124, but do not apply an axial preload force to the bases 124. In such a configuration, the bridge member 140 may be formed from a horizontally oriented laminate, as in one embodiment, but coupled to the base 124 using an adhesive.

Fig. 3 is a perspective view of an alternative embodiment of electric motor 208, showing an alternative stator assembly 212. Stator assembly 212 is substantially similar in operation and composition to stator assembly 112 (shown in fig. 1 and 2), except that spool 202 of stator assembly 212 includes an extension flange 204 to retain bridge member 140 instead of fasteners 156. Accordingly, similar components shown in fig. 3, such as the base 424 and the bridge member 140, are labeled with the same reference numerals as in fig. 1 and 2.

Stator assembly 212 includes a plurality of spools 202 coupled to a base 424. Each bobbin 202 includes an opening that closely conforms to the outer shape of the stator teeth 132. As described herein, the stator teeth 132 are configured to be inserted into a first end of the bobbin opening and exit a second end of the opening before the stator teeth 132 are coupled to the receiving slots 138. Stator assembly 212 may include one spool 202 for each tooth 132 or one spool 202 positioned on every other tooth 132. Each bobbin 202 also includes electrical windings (not shown) comprising a plurality of coils wound on the respective bobbin 202, the bobbins 202 electrically isolating the coils of the windings from the stator teeth 132 and the tooth tips 134.

In the embodiment shown in fig. 3, each spool 202 includes a pair of extending flanges 204 that extend axially from opposing circumferential ends of each spool 202 proximate to the base 124. Each extension flange 204 engages an adjacent bridge member 140 to hold the bridge member 140 in place. More specifically, each extension flange 204 engages both the first axial surface 142 and the radially outer surface 149 of its respective bridge member 140. In this configuration, the extension flange 204 exerts an axially downward force on the bridge member 140 to hold the base 124 in place on the frame 122 in a manner similar to the fastener 156 of the embodiment of fig. 1 and 3. Additionally, the extension flange 204 engages the radially outer surface 149 of the bridge member 140 to hold the bridge member 140 in place during operation of the motor 208.

Fig. 4 is a perspective view of another alternative embodiment of a stator assembly 312. Fig. 5 is a perspective view of a bridge ring 302 used in the stator assembly 312 shown in fig. 4. Stator assembly 312 is substantially similar in operation and composition to stator assembly 112 (shown in fig. 1 and 2), except that stator assembly 312 includes a bridge ring 302 having a connecting ring 304 and a plurality of bridge members 306, rather than a separate plurality of bridge members 140 of stator assembly 112. Thus, similar components shown in FIG. 4, such as the base 424 and the tooth assembly 130, are labeled with the same reference numerals as used in FIGS. 1 and 3.

The bridge ring 302 includes a connecting ring 304 integrally formed with a plurality of bridge members 306 to connect the members 306 together. As shown in fig. 4 and 5, the connecting ring 304 is located radially inward of the bridge member 306. In an alternative embodiment, the connecting ring 304 is located radially outward of the bridge member 306. The bridge ring 302 may be used with the fastener 156 of the stator assembly 112 or with the spool extension flange 204 of the stator assembly 212 (when the bridge ring 304 is radially inward of the bridge member 306). Alternatively, the bridge ring 302 may be used independently of the fastener 156 and the extension flange 204. Similar to the bridge member 140, the bridge ring 302 is formed from a plurality of horizontal laminations for the same reasons as described above. When manufacturing a large number of stator assemblies 312 having a known pole count, bridge ring 302 allows bridge member 306 to be more easily installed into stator assembly 312.

A method of assembling axial flux motor 108 is described herein. The method includes coupling at least one base 424 to the motor frame 122, wherein the base 424 includes a receiving slot 138. The method further includes inserting the tooth assembly 130 at least partially into the receiving slot 138 of each base 424. The method further includes coupling the bridge member 140 to a pair of circumferentially adjacent bases 124 such that the bridge member 140 extends between the circumferentially adjacent bases 124 and applies an axial preload force to the bases 124.

Fig. 6 is a perspective view of the motor 400. Fig. 7 is a sectional view of the motor 400. Fig. 8 is a perspective view of a stator assembly 412 for the motor 400 shown in fig. 6. Fig. 9 is an exploded view of a portion of the stator assembly 412, showing the bobbin. In the exemplary embodiment, motor 400 is an axial flux motor that includes a rotor assembly 410 and a stator assembly 412, stator assembly 412 being coupled to rotor assembly 410 to define an axial gap 414 therebetween. The rotor assembly 410 generally includes a rotor 416 and at least one permanent magnet 418 coupled to the rotor 416. In the exemplary embodiment, permanent magnet 418 is made of ferrite and is formed as a single disk having multiple poles. Optionally, the permanent magnet 418 includes a plurality of magnet segments connected to the rotor 416. In general, any suitable permanent magnet shape, number of segments, and material may be used that enables motor 400 to function as described herein. The rotor assembly 410 is rotatable about an axis of rotation 420. In the exemplary embodiment, motor 400 is energized by an electronic controller (not shown), such as a sinusoidal or trapezoidal output electronic controller. In the exemplary embodiment, rotor 416 is machined and/or cast from any suitable material (e.g., steel).

The stator assembly 412 is a multi-phase (more than one phase) axial flux stator, and is preferably a three-phase axial flux stator that generates magnetic flux in an axial direction (i.e., parallel to the axis of rotation 420). The stator assembly 412 includes a motor frame 422 connected to a blower housing (not shown) and a plurality of circumferentially spaced tooth assemblies 423 connected to the motor frame 422. In the exemplary embodiment, each tooth assembly 423 includes a base 424 that is coupled to motor frame 422. The tooth assembly 423 also includes a tooth portion 426 extending axially from the base 424 and a tooth tip 428 coupled to an end of the tooth portion 426 opposite the base 424.

As shown in fig. 8 and 9, each tooth assembly 423 is formed from a plurality of stacked laminations, and each lamination includes one tooth point 428, one tooth portion 426, and one base 424. Specifically, each lamination includes a tooth 426 integrally formed as a single piece with the base 424. More specifically, each lamination includes a point 428 integrally formed with a tooth 426 and a base 424 such that the point 428, tooth 426 and base 424 of each lamination are formed as a unitary member from a single component.

Forming the tooth assemblies 423 from stacked laminations simplifies the manufacturing process and enables each tooth assembly 423 to be produced quickly and efficiently. The teeth 426 have substantially the same width from the inner edge to the outer edge. This allows the laminate sheets from which the tooth assemblies 423 are made to be substantially identical, which reduces manufacturing costs. In addition, each laminate sheet of the tooth assembly 423 includes a pair of laminate interlocks that facilitate connecting a plurality of laminate sheets together to form the tooth assembly 423 having a desired width. The laminated interlocking portion is formed as a recess on one side of the tooth assembly 423 and a protrusion on the opposite side. In this way, the protrusion of one interlocking portion of a first sheet mates with the recess of another interlocking portion on an adjacent sheet. Optionally, the laminated interlocking portion has any form that facilitates operation of the tooth assembly 423 as described herein. In another embodiment, the tooth assembly 423 is formed from a Soft Magnetic Composite (SMC).

In the exemplary embodiment, stator assembly 412 also includes a plurality of circumferentially spaced bridge members 430 that engage a pair of circumferentially adjacent bases 424 to apply an axial preload force to the bases to maintain bases 424 in their desired positions and to form a flux path between adjacent bases 424. As best shown in fig. 8, the bridge member 430 is substantially trapezoidal in shape and includes a first axial surface 432, a second axial surface 434, a first circumferential end surface 436, and a second circumferential end surface 438. In the exemplary embodiment, each base 424 includes a pair of substantially similar end shoulders 440, each defined by an axial surface 442 and a circumferential end surface 444.

In operation, each bridge member 430 engages an adjacent end shoulder 440 of a circumferentially adjacent base 424. More specifically, the second axial surface 434 of the bridge member 430 engages the shoulder axial surfaces 442 of two circumferentially adjacent end shoulders 440 to apply an axial force to the axial surfaces 442. In some embodiments, the first circumferential end surface 436 of each bridge member 430 engages a respective shoulder circumferential end surface 444 of the first base 424, and the second circumferential end surface 438 of each bridge member 430 engages a respective shoulder circumferential end surface 444 of the second base 424 circumferentially adjacent the first base 424.

In the exemplary embodiment, stator assembly 412 also includes a plurality of fasteners 446 that connect bridge member 430 to frame 422. More specifically, each bridge member 430 includes an opening 448 defined therethrough that receives the fastener 446. The fasteners 446 extend through the openings 448 and between the bridge members 430 and the frame 422 to secure the base 424 to the frame 422. As such, the fastener 446 exerts an axial force on the bridge member 430 that is transmitted to the base 424 through the engagement of at least the

axial surfaces

434 and 442. In this configuration, the base 424 spaces the bridge member 430 from the frame 422 to define a gap therebetween. In an exemplary embodiment, the fastener 446 is a non-magnetic or low magnetic screw. In another embodiment, the fastener 446 is a rivet or a clamp. Collectively, the fasteners 446 are any type of retention device that facilitates operation of the stator assembly 412 as described herein. In this manner, the bridge member 430 applies an axial preload force to the base 424 and holds the stator assembly 412 together without the need for overmolding with resin, thereby reducing costs and increasing the efficiency of the motor 400.

As shown in fig. 6 and 8, the bridge member 430 is formed of a plurality of stacked laminations similar to the tooth assembly 423. In another embodiment, the tooth assembly 423 is formed from a Soft Magnetic Composite (SMC). However, as described above, the tooth assembly 423 is formed from a vertically oriented stack, while the bridge member 430 is formed from a plurality of horizontally oriented stacks. This difference in orientation between the base portions 424 and the bridge members 430 reduces the occurrence of eddy currents and enables magnetic flux to flow efficiently between the base portions 424 because the horizontal stacks of bridge members 430 are oriented in the same direction that the magnetic flux exits the base portions 424. Further, in one embodiment, stator assembly 412 includes a very thin insulating layer (not shown), such as, but not limited to, a sheet of material or a coated coating between base 424 and bridge member 430 to prevent shorting of the stack and further reduce the formation of eddy currents.

As described herein, in the exemplary embodiment, bridge member 430 both applies an axial preload force to base 424 and creates an effective magnetic flux path between adjacent tooth assemblies 423. In one embodiment, the bridge member 430 is used only to apply an axial preload force, and does not promote flux flow. In such a configuration, the bridge member 430 may be formed of a material different from the stacked laminations and serve as a clamp to secure the base 424 to the frame 422. Alternatively, in another embodiment, the bridge members 430 serve only to promote efficient flux flow between adjacent bases 424 without applying an axial preload force to the bases 424. In such a configuration, the bridge member 430 may be formed of horizontally oriented laminations as in the exemplary embodiment, but coupled to the base 424 using an adhesive.

Returning to fig. 7 and 9, the stator assembly 412 also includes a plurality of bobbins 450, each connected to a respective tooth 426. In this embodiment, the bobbin 450 is a split bobbin configuration and includes a first bobbin portion 452 and a second bobbin portion 454. Because the tooth assembly 423 includes the tooth tip 428, the split spool configuration facilitates connecting the first spool portion 452 to the second spool portion 454 such that the

spool portions

452 and 454 surround the tooth 426. Once the bobbin 450 is connected to the tooth assembly 423, the coil 456 is wound on the bobbin 450.

Referring now to fig. 7, the motor 400 further includes a shaft 458 and a pair of bearing

assemblies

460 and 462 coupled to the shaft 458. Specifically, frame 422 includes a bearing locator 464 that extends axially through stator assembly 412. As shown in fig. 7, bearing

assemblies

460 and 462 are positioned within bearing locator 464. Bearing spacer 466 is positioned within bearing retainer 464 between a pair of bearing

assemblies

460 and 462. Additionally, a bearing spring 468 is positioned within the bearing locator 464 between the pair of bearing

assemblies

460 and 462, with a bearing spacer 466 positioned between the bearing spring 468 and the bearing assembly 460 of the pair of bearing assemblies. Bearing spring 466 acts as a spacer to maintain a desired distance between bearing

assemblies

460 and 462 while allowing the use of a shorter bearing spring 468, which reduces costs. The use of plastic bearing spacer 466 also reduces noise generated by motor 400 by replacing the metal-to-metal engagement when a longer bearing spring is used than bearing spring 468.

Example methods and systems for an axial flux motor are described herein. An axial-flux electric machine includes a stator assembly having a plurality of circumferentially spaced tooth assemblies, each tooth assembly including a tooth and a base integrally formed with the tooth. The stator assembly also includes a plurality of circumferentially spaced bridge members, each bridge member configured to engage a pair of circumferentially adjacent bases. The bridge member is connected between circumferentially adjacent bases to apply an axial preload force to the bases and to facilitate flux flow between adjacent bases. The laminations that make up the bridge member are oriented so that the magnetic flux direction does not generate eddy currents, but still allows the lamination direction to create structural members to hold the stator components in place. The mechanical interface between the base and the bridge member holds the stator assembly together without the need to over-mold the stator assembly with resin, thus reducing cost and improving efficiency of the electric machine. The resulting construction allows for any custom motor size.

Exemplary embodiments of axial flux motor assemblies are described above in detail. The motor and its components are not limited to the specific embodiments described herein, but rather, components of the system may be utilized independently and separately from other components described herein. For example, the various components may also be used in combination with other machine systems, methods, and apparatus, and are not limited to practice with only the systems and apparatus as described herein. Rather, the exemplary embodiment can be implemented and utilized in connection with many other applications.

Although specific features of various embodiments of the invention may be shown in some drawings and not in others, this is for convenience only. In accordance with the principles of the invention, any feature of a drawing may be referenced and/or claimed in combination with any feature of any other drawing.

This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they do not differ from the structural elements described in the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.

Claims

1. A stator assembly for an axial flux electric motor, the stator assembly comprising:

a plurality of circumferentially spaced apart tooth assemblies, wherein each tooth assembly comprises a tooth portion and a base portion; and

a plurality of circumferentially spaced apart bridge members, wherein each bridge member is configured to engage a pair of circumferentially adjacent bases.

2. The stator assembly of claim 1, further comprising a frame and a plurality of fasteners, wherein each bridge member includes an opening defined therethrough configured to receive a respective fastener of the plurality of fasteners, wherein the plurality of fasteners extend between the bridge member and the frame to apply an axial preload force to the base.

3. The stator assembly of claim 1, wherein each tooth portion includes a tooth tip positioned opposite the base.

4. The stator assembly of claim 1, wherein the plurality of tooth assemblies are each formed from a plurality of vertically oriented laminations, and wherein the plurality of bridge members are formed from a plurality of horizontally oriented laminations, wherein a magnetic flux path is formed between adjacent bases through the respective bridge members.

5. The stator assembly of claim 1, wherein each base includes a pair of end shoulders, and wherein each bridge member engages adjacent end shoulders of circumferentially adjacent bases.

6. The stator assembly of claim 1, further comprising a plurality of spools connected to respective teeth, wherein each spool comprises a split spool configuration having a first spool portion and a second spool portion.

7. The stator assembly of claim 1, wherein each tooth assembly is formed from a plurality of stacked laminations, wherein each lamination includes one tooth integrally formed with one base as a single piece.

8. The stator assembly of claim 7, wherein each tooth assembly further comprises a tooth tip at an end of the tooth portion opposite the base, wherein each lamination includes one tooth tip integrally formed as a single component with the tooth portion and the base.

9. An axial flux electric motor comprising:

a frame;

a rotor assembly; and

a stator assembly coupled to the frame and positioned adjacent to the rotor assembly to define an axial gap therebetween, wherein the stator assembly comprises:

10. The axial flux electric motor of claim 9, further comprising a frame and a plurality of fasteners, wherein each bridge member includes an opening defined therethrough configured to receive a respective fastener of the plurality of fasteners, wherein the plurality of fasteners extend between the bridge member and the frame to apply an axial preload force to the base.

11. The axial flux electric motor of claim 9, wherein the frame includes a bearing locator, and wherein the electric motor further comprises:

a pair of bearing assemblies positioned within the bearing locator; and

a bearing spacer positioned between the pair of bearing assemblies within the bearing locator.

12. The axial flux motor of claim 11, further comprising a bearing spring positioned between the pair of bearing assemblies within the bearing locator, wherein the bearing spacer is positioned between the bearing spring and one of the pair of bearing assemblies.

13. The axial flux electric motor of claim 9, wherein each base includes a pair of end shoulders, and wherein each bridge member engages adjacent end shoulders of circumferentially adjacent bases.

14. The axial flux electric motor of claim 9, wherein the plurality of tooth assemblies and the plurality of bases are each formed from a plurality of vertically oriented laminations, and wherein the plurality of bridge members are formed from a plurality of horizontally oriented laminations, wherein a flux path is formed between adjacent bases through the respective bridge members.

15. The axial flux electric motor of claim 9, wherein each tooth assembly is formed from a plurality of stacked laminations, wherein each lamination includes a tooth tip positioned at an end of the tooth opposite the base, wherein each lamination is integrally formed as a single component.

16. A method of assembling an axial flux electric motor, the method comprising:

coupling a plurality of circumferentially spaced tooth assemblies to the frame, wherein each tooth assembly includes a base coupled to the frame and a tooth extending axially from the base; and

coupling a bridge member to a pair of circumferentially adjacent bases such that the bridge member extends between the circumferentially adjacent bases.

17. The method of claim 16, further comprising:

inserting a fastener through an opening defined in the bridge member; and

a fastener is coupled to the frame to apply an axial preload force to the base.

18. The method of claim 16, wherein coupling the bridge member includes coupling the bridge member to an end shoulder of each of the circumferentially adjacent bases such that the bridge member is spaced apart from the frame by the circumferentially adjacent bases.

19. The method of claim 16, further comprising:

coupling a first portion of a spool to a second portion of the spool such that first and second spool portions encircle the tooth, wherein the first and second spool portions are positioned between the base and a tooth tip of the tooth.

20. The method of claim 16, further comprising coupling a bearing spacer and a bearing spring between a pair of bearing assemblies within a bearing locator of the frame.