Hybrid stepping motor using axial coils for adjusting the rotor's magnetic field.

Abstract

This invention relates to a hybrid stepping motor that utilizes an axial coil that can be energized to correct the magnetic field generated by the rotor during the operation of the hybrid stepping motor. [Solution] The bipolar hybrid stepping motor 12 includes a stator 16 with a primary winding 20. The stator and primary winding are housed in a housing 120. The rotor 14 has magnetic components. The rotor is rotatable relative to the stator. An axial coil assembly 24 is housed in the housing, positioned close to both ends of the rotor, and has secondary windings. At least a portion of the rotor's magnetic components is generated by the energized axial coil assembly. The energized state creates an electromagnetic communication between the rotor and the stator.

Description

Technical Field

[0001] The present invention generally relates to electric motors, and more specifically to a hybrid stepper motor that utilizes axial coils that can be energized to modify the magnetic field generated by the rotor during operation of the hybrid stepper motor.

Background Art

[0002] In conventional motors, a stepper motor typically includes a stator and a rotor that cooperate to generate an electromotive force that rotates the rotor relative to the stator. Each of the stator and the rotor has a plurality of teeth that cooperate electromagnetically with each other to produce a small, incremental rotational change in the position of the rotor relative to the stator. In a hybrid stepper motor, the rotor generates an electromagnetic field that cooperates with a separate electromagnetic field generated by an energized winding wound around the teeth of the stator. These electromagnetic fields of the rotor and the stator cooperate to generate an electromotive force that rotates the rotor relative to the stator. The movement of the rotor is generated by energizing the windings wound around the teeth of the stator in different sequences that rotate the magnetic field of the rotor so that the opposing poles of the rotor and the stator are aligned. The continuous rotational movement of the rotor relative to the stator can be achieved by sequencing the current supplied to the various windings of the stator.

Summary of the Invention

[0003] According to one aspect of the present invention, an electric motor assembly includes a stator having a primary winding. A rotor is rotatable relative to the stator. An axial coil assembly is disposed proximate to both ends of the rotor and has a secondary winding. When at least the secondary winding is energized, the rotor is in electromagnetic communication with the stator. When the primary winding and the secondary winding are energized, the rotor is in electromagnetic communication with the stator via an electromotive force that rotates the rotor relative to the stator.

[0004] According to another aspect of the present invention, a bipolar hybrid stepping motor includes a stator having a primary winding. The stator and primary winding are housed within a housing. The rotor has magnetic components. The rotor is rotatable relative to the stator. An axial coil assembly is housed within the housing, positioned close to both ends of the rotor, and has secondary windings. At least a portion of the rotor's magnetic components is generated by the energized axial coil assembly. The energized state generates an electromagnetic communication between the rotor and the stator.

[0005] According to another aspect of the present invention, a method for operating a bipolar hybrid stepping motor includes energizing the windings of the stator. The rotor rotates relative to the stator. A first magnetic component of the rotor is generated via an axial coil assembly. The rotor operates using a first electromotive force generated by the excitation windings of the stator and the first magnetic component of the rotor. The current is modified relative to the axial coil assembly. A second magnetic component of the rotor operates via the modified current of the axial coil assembly. The first magnetic component is distinct from the second magnetic component. The rotor operates using a second electromotive force generated by the excitation windings of the stator and the second magnetic component of the rotor.

[0006] These and other aspects, purposes and features of the present invention will be understood by those skilled in the art by examining the following specification, claims and accompanying drawings. [Brief explanation of the drawing]

[0007] [Figure 1] This is a perspective view of a hybrid stepping motor incorporating one embodiment of an axial coil for providing magnetic flux to the rotor in order to correct the rotor's magnetic field. [Figure 2] This is a cross-sectional view of the motor in Figure 1 along line II-II. [Figure 3]This is a side view of one embodiment of a hybrid stepping motor with the housing removed, showing the positioning of the axial coils relative to the dataer and rotor. [Figure 4] This is an exploded perspective view of one embodiment of a hybrid stepping motor that incorporates axial coils to supply magnetic flux to the rotor in order to correct the magnetic field generated by the rotor. [Figure 5] This is a schematic elevation view of a hybrid stepping motor incorporating one form of axial coil. [Figure 6] This is a cross-sectional view of the stepping motor in Figure 1 along line VI-VI, showing the axial coil in an energized state. [Figure 7] This is an enlarged cross-sectional view of the hybrid stepping motor in Area VII, as shown in Figure 6. [Figure 8] This is a schematic diagram of one embodiment of a hybrid stepping motor in which the axial coil assembly is not energized. [Figure 9] Figure 8 is a schematic diagram of the hybrid stepping motor with the axial coil assembly energized. [Figure 10] This is a top perspective view of a vehicle selector dial incorporating one embodiment of a hybrid stepping motor having an axial coil. [Figure 11] This is a schematic plan view of one embodiment of a rotary dial incorporating a hybrid stepping motor that utilizes axial coils. [Figure 12] This is a schematic plan view of one embodiment of a rotary dial incorporating a hybrid stepping motor that utilizes axial coils. [Figure 13] This is a schematic plan view of one embodiment of a rotary dial incorporating a hybrid stepping motor that utilizes axial coils. [Figure 14] This is a schematic plan view of one embodiment of a rotary dial incorporating a hybrid stepping motor that utilizes axial coils. [Figure 15] This is a linear flowchart illustrating how to operate a hybrid stepping motor that utilizes axial coils to supply magnetic flux to the rotor. [Modes for carrying out the invention]

[0008] For the purposes of this description, terms such as “upper,” “lower,” “right,” “left,” “rear,” “front,” “vertical,” and “horizontal,” and their derivatives, are used in reference to the present invention as oriented in Figure 1. However, naturally, the present invention may take on various alternative orientations unless explicitly specified to the contrary. Also naturally, the specific apparatus and processes illustrated in the accompanying drawings and described in the following specification are merely illustrative embodiments of the concept of the invention as defined in the accompanying claims. Therefore, unless explicitly stated otherwise in the claims, specific dimensions and other physical characteristics relating to the embodiments disclosed herein are not considered limiting.

[0009] As illustrated in Figures 1 to 9, reference numeral 10 generally refers to an electric motor or electric motor assembly, and typically refers to a hybrid stepping motor 12 having a rotor 14 that rotates relative to a stator 16 to rotate a drive shaft 18 connected to the rotor 14. The drive shaft 18 is then connected to the mechanical components of a device for rotating or otherwise operating a part of a larger assembly. According to various embodiments of the device, the electric motor 10 includes a stator 16 having a set of primary windings 20 that can be energized by applying a current 22 to the primary windings 20. The rotor 14 is also included in the electric motor 10, and the rotor 14 is rotatable relative to the stator 16. An axial coil assembly 24 is positioned close to the end 26 of the rotor 14 and includes a set of secondary windings 28. In various embodiments of the device, when the secondary windings 28 are energized via a secondary current 30, the rotor 14 is arranged to be in electromagnetic communication with the stator 16. When the primary winding 20 and the secondary winding 28 are energized, the rotor 14 is in electromagnetic communication with the stator 16 via the electromotive force 32 that causes the rotor 14 to rotate.

[0010] Referring again to Figures 2-9, during the operation of the electric motor 10, a current 22 is supplied to the windings of the stator 16. This current 22 is distributed to the primary windings 20 of the stator, typically energizing opposing sets of windings at different times. Energizing the primary windings 20 in this manner alters the magnetic field 40 generated through the current 22 energizing the primary windings 20 according to a predetermined pattern or sequence. The rotor 14 includes a magnetic component 42 configured to interact with the magnetic field 40 generated by the energized primary windings 20. This magnetic component 42 generates a rotor magnetic field 44 that tends to align with the magnetic field 40 generated by the energized primary windings 20 of the stator 16. Therefore, when different primary windings 20 of the stator 16 are energized, the magnetic component 42 of the rotor 14 causes the rotor 14 to tend to align with the magnetic field 40. As a result, the rotor 14 rotates relative to a predetermined sequence of energized primary windings 20 in the stator 16.

[0011] As illustrated in Figures 2-9, the secondary winding 28 of the axial coil assembly 24 is energized through a secondary current 30 supplied to the axial coil assembly 24 in order to generate the magnetic components 42 of the rotor 14. When the axial coil assembly 24 is energized, it generates a coil magnetic field 50 that provides a magnetic flux 52 through the end 26 of the rotor 14. This magnetic flux 52 then generates the magnetic components 42 of the rotor 14 and generates a rotor magnetic field 44 that interacts with the magnetic field 40 generated by the energized primary winding 20. The secondary current 30 supplied to the secondary winding 28 of the axial coil assembly 24 can be varied. In this way, the coil magnetic field 50 generated by the energized axial coil assembly 24 can also be modified to direct magnetic flux 52 of different magnitudes towards the end 26 of the rotor 14. The variation in magnetic flux 52 supplied to the rotor 14 may differ depending on the magnitude of the magnetic components 42 of the rotor 14 that generate the rotor magnetic field 44. In other words, increasing or decreasing the secondary current 30 supplied to the axial coil assembly 24 can modulate or change the magnitude of the magnetic components 42 of the rotor 14.

[0012] As an example, and not an limitation, certain embodiments of the rotor 14 may include magnetic members 60 within the body 62 of the rotor 14. These magnetic members 60 are typically small in size and / or may have a small rotor magnetic field 44. Thus, the magnetic members 60 that may be placed within the rotor 14 are of a size that provides only a small amount (e.g., about one-third) of the total potential magnetic components 42 that can be provided by the rotor 14 when the axial coil assembly 24 is energized by the secondary current 30. If the secondary current 30 is not supplied to the axial coil assembly 24 and the magnetic components 42 consist only of the magnetic members 60, the rotor magnetic field 44 generated by the rotor 14 may be minimal. This minimal rotor magnetic field 44 can magnetically interact with the teeth of the stator 16, which is typically made of iron material. Iron material can interact with the rotor magnetic field 44 of the rotor 14 even when the primary windings 20 are not energized. Therefore, if current 22 is not supplied to the primary winding 20 and secondary current 30 is not supplied to the axial coil assembly 24, the rotation of the rotor 14 may result in a minimal detent feel between the magnetic member 60 of the rotor 14 and the stator teeth 66 of the stator 16. This minimal detent feel may be perceptible to the user of the device, or it may be so slight that it is relatively imperceptible to the user.

[0013] When the secondary current 30 is supplied to the axial coil assembly 24, the rotor magnetic field 44 of the rotor 14 expands or increases, and the locking sensation between the rotor teeth 64 and the stator teeth 66 may also increase. If the secondary current 30 to the axial coil assembly 24 increases further, the rotor magnetic field 44 may increase to the point where the rotor 14 no longer moves within the stator 16. In such a configuration, the rotor magnetic field 44 spreading around the rotor 14 is magnetically attracted to the iron material of the stator 16 until it becomes unable to rotate, and the rotor 14 is rotationally fixed relative to the stator 16.

[0014] In various aspects of the device, the magnetic component 42 of the rotor 14 can be provided solely by the axial coil assembly 24. In such embodiments, no magnetic member 60 is disposed within the body 62 of the rotor 14, and the magnetic component 42 of the rotor 14 is provided only via the secondary current 30 provided to the axial coil assembly 24. In this aspect of the device, the axial coil assembly 24 is demagnetized and no secondary current 30 is supplied thereto. Thus, the rotor 14 does not include a rotor magnetic field 44 and can rotate freely within the stator 16. In this way, magnetic interaction between the rotor 14 and the stator 16 may not be perceived. This is particularly likely to apply when the primary coil is not energized and no current 22 is supplied to the primary winding 20.

[0015] Referring again to FIGS. 1-9, the exemplary electric motor 10 is shown in an inner rotor configuration, and the rotor 14 rotates within a cavity 80 defined within the teeth of the stator 16. It should be understood that the electric motor 10 described herein can also be configured in an outer rotor configuration, and the rotor 14 is in the form of a ring that rotates around a central stator core.

[0016] As illustrated in FIGS. 1-7, the electric motor 10 is typically a bipolar hybrid stepper motor 12, and the rotor 14 includes the shape of rotor teeth 64 having a plurality of rotor teeth 64 defined within the outer periphery 90 of the rotor 14. This shape of the rotor teeth 64 of the rotor 14 can include as few as two rotor teeth 64, but typically 50 teeth. It is also contemplated that the rotor 14 can include 200 or 400 rotor teeth 64 defined within the outer periphery 90 of the rotor 14.

[0017] In conventional hybrid stepping motors, each tooth defined within the outer surface of the rotor contains a dedicated magnet that cooperates with the stator to correct the rotor's position relative to the stator. These conventional hybrid stepping motors also contain a consistent magnetic field generated by the rotor to interact with the stator's energized windings. In these conventional hybrid stepping motors, fine-tuning the anti-return force between the rotor and stator is difficult, typically leading to a loss of the maximum torque the rotor can provide.

[0018] As illustrated in various embodiments of the apparatus, as shown in Figures 1 to 9, the rotor 14 may include magnetic members 60 within each rotor tooth 64 defined within the outer circumference 90 of the rotor 14. As described above, these magnetic members 60 typically generate a rotor magnetic field 44 that is smaller in size or smaller than the rotor magnets contained in conventional motors. Although the magnetic members 60 of the rotor 14 generate a smaller rotor magnetic field 44, this loss of magnetic field 40 is explained by the addition of an axial coil assembly 24 that can be energized by the application of a secondary current 30. The magnetic members 60 contained within the rotor 14 can define a minimum torque 198 or minimum locking force that can cooperate with the stator teeth 66 of the stator 16 to rotate the rotor 14. This minimum locking force can define what the user experiences as a light click or locking sensation. When the secondary current 30 is supplied to the axial coil assembly 24, the rotor magnetic field 44 generated by the rotor 14 can be modified, corrected, or modulated in a fine-tuning process that produces a wide range of magnitudes and configurations of the rotor magnetic field 44 generated by the rotor 14.

[0019] As illustrated in FIGS. 6 and 7, the end 26 of the rotor 14 of the hybrid stepper motor 12 includes opposing rotor poles 100 that can define a negative electrode 102 and a positive electrode 104. Each of these rotor poles 100 disposed at the end 26 of the rotor 14 is positioned proximate to respective first and second sets 106, 108 of the posts 110 of the axial coil assembly 24. The secondary winding 28 is wound around these posts 110. When the secondary winding 28 is energized, each of the posts 110 includes positive and negative end portions 112, 114 that at least partially define the rotor poles 100 of the rotor 14. As shown in FIG. 7, the posts 110 of the axial coil assembly 24 include a positive end portion 112 distal from the rotor 14 and a negative end portion 114 adjacent or proximate to the rotor 14. When the secondary winding 28 of the axial coil assembly 24 is energized, the magnetic field 40 generated by the posts 110 of the axial coil assembly 24 provides magnetic flux 52 to the stator 16. This magnetic flux 52 generates a negative electrode 102 at the end 26 of the stator 16, as shown in FIG. 7, from the negative end portion 114 of the secondary winding 28. At the opposite end 26 of the rotor 14, the opposite is normally true such that the opposite pole of the rotor 14 is positively charged by the positive end portion 112 of the secondary winding 28 to generate the positive electrode 104 of the rotor 14. Thus, the positive and negative electrodes 104, 102 of the rotor 14 are generated through the energized axial coil assembly 24 that generates the magnetic flux 52 projected to each end 26 of the rotor 14.

[0020] In various aspects of an apparatus where the rotor 14 includes a magnetic member 60, the axial coil assembly 24 can augment the positive and negative electrodes 104, 102 within the rotor 14 that match the polarity of the magnetic member 60 included within the rotor 14.

[0021] Depending on the various configurations within the apparatus, the magnetic polarity of the magnetic member 60 can generate a rotor magnetic field 44 of a certain magnitude emanating from the rotor 14. The axial coil assembly 24 can be used opposite or superimposed on the magnetic member 60 to not only add to or amplify the rotor magnetic field 44 generated by the rotor 14, but also to reduce the magnitude of the rotor magnetic field 44 generated by the rotor 14. Therefore, if the magnetic member 60 generates a negative pole 102 at the end 26 of the rotor 14, the axial coil assembly 24 can be configured by applying a secondary current 30 to position a coil magnetic field 50 opposite the end 26 of the rotor 14. These opposing magnetic poles of the magnetic member 60 and the secondary winding 28 can at least partially cancel each other out, generating a reduced rotor magnetic field 44 that is smaller than the intensity of the magnetic member 60 alone.

[0022] According to various embodiments of the apparatus, the coil magnetic field 50 generated by the axial coil assembly 24 can be used to fine-tune the rotor magnetic field 44 generated by the rotor 14, thereby generating a rotor magnetic field 44 of a desired magnitude that interacts with the magnetic field 40 generated by the primary winding 20 of the stator 16. This modification of the rotor magnetic field 44 of the rotor 14 also allows the amount of torque 198 generated by the rotor 14 with respect to the stator 16 to be varied according to the needs of a particular electric application.

[0023] Referring again to Figures 2 to 9, as described above, typically the rotor 14 is an inner rotor that rotates within an internal cavity 80 defined by the stator 16 and the primary winding 20. The current 22 supplied to the primary winding 20 is usually an alternating current. The secondary winding 28 of the axial coil assembly 24 can also be energized by applying a secondary current 30. Typically, this secondary current 30 is a direct current.

[0024] As illustrated in Figures 1-7, the electric motor 10 may be in the form of a bipolar hybrid stepping motor 12 having a stator 16 including a primary winding 20. The stator 16 and the primary winding 20 are typically housed within a housing 120. The stator 16 can be made from a series of stacked laminates 122, which are typically made from iron material. The windings are then wound around poles 170 formed by the stacked laminates 122 of the stator 16. The stator 16 is then overmolded, or at least partially enclosed, by the housing 120 in the form of an overmolding that surrounds the primary winding 20 and the stacked laminates 122 of the stator 16. The rotor 14 of the electric motor 10 includes a magnetic component 42, and the rotor 14 is rotatable relative to the stator 16. An axial coil assembly 24 is housed within the housing 120 and is located close to the ends 26 of the rotor 14. The secondary winding 28 of the axial coil assembly 24 is wound around the post 110 of the axial coil assembly 24. Typically, the secondary winding 28 and post 110 of the axial coil assembly 24 may also be housed within the housing 120 and overmolded together with the rest of the stator 16. Alternatively, the axial coil assembly 24 may be in the form of one or more separate caps 124 that can be coupled with the housing 120 and the rest of the stator 16 and fix the position of the axial coil assembly 24 relative to the rotor 14. As described above, at least a portion of the magnetic components 42 of the rotor 14 is generated by the axial coil assembly 24 when energized by the application of the secondary current 30. The energized state of the axial coil assembly 24 creates at least partial electromagnetic communication between the rotor 14 and the stator 16. As described above, this electromagnetic communication can be generated by the application of magnetic flux 52 from the axial coil assembly 24 directed toward the end 26 of the rotor 14. This magnetic flux 52 generates at least partially rotor poles 100 facing the ends 26 of the stator 16, and then generates a rotor magnetic field 44 that can interact with the energized primary windings 20 of the stator 16.As shown in Figures 6 and 7, the axial coil assembly 24 includes a first set 106 of posts 110 located at one end 26 of the rotor 14 and a second set 108 of posts 110 located at the opposite end 26 of the rotor 14. Typically, the axial coil assembly 24 is rotatably fixed in or relative to the housing 120 so that the rotor 14 rotates relative to the stator 16 and the axial coil assembly 24. In various embodiments of the apparatus, when the rotor 14 and the axial coil assembly 24 operate around the rotation axis 154 of the rotor 14, the axial coil assembly 24 may rotate with the rotor 14 to provide magnetic flux 52 to the rotor 14. Typically, the axial coil assembly 24 is rotatably fixed to the stator relative to the rotor 14.

[0025] As illustrated in Figures 2-14, during the operation of the hybrid stepping motor 12, the sequence of currents 22 supplied to the primary winding 20 typically operates in a sequence that generates an electromotive force 32 that causes or stops the rotation of the rotor 14 relative to the stator 16. In one exemplary embodiment of the device, an axial coil assembly 24 can be utilized to provide an electromotive force 132 that stops the rotation of the rotor 14 relative to the stator at a predetermined rotational position 134. Using a positioning sensor 136, once the rotor 14 has achieved a specific rotational position 134, the axial coil assembly 24 can be energized by applying a secondary current 30. As described herein, this secondary current 30 can generate a rotor magnetic field 44 of sufficient magnitude. This rotor magnetic field 44 interacts with the primary magnetic field 40 applied by the windings of the stator 16 to generate an electromotive force 132 that prevents the rotation of the rotor 14 relative to the stator 16. This electromotive force 132 can be used to define an outer limit 138 of the rotation of the rotor 14 relative to the stator 16.

[0026] Referring here to Figures 10-14, in exemplary embodiments of the hybrid stepping motor 12 disclosed herein, the windings of the stator 16 and the secondary winding 28 of the axial coil assembly 24 can work in coordination to operate a rotary dial, such as a rotary selector dial 150. Using the primary and secondary windings 20, 28 of the stator 16 and the axial coil assembly 24, respectively, a tactile component 152 can be achieved, which can be perceived by the user during operation of the rotary selector dial 150. The tactile component 152 can be in the form of auditory and / or tactile feedback that can be generated by the hybrid stepping motor 12, and when the selector dial 150 is operated around the rotary axis 154, the rotation of the rotor 14 relative to the stator 16 can be in the form of a drag force that provides the feel of a high-friction interface. The tactile component 152 may also take the form of one or more stoppers 156, a vibrating component 158, operation within a defined range of rotation 160 around a rotation axis 154, application of an opposing electromotive force 162 by the user to counteract the operation of the selector dial 150, and other similar tactile components 152.

[0027] As illustrated in Figures 2-9, the primary windings 20 of the stator 16 are typically energized by phased currents 22. In these phases, only a portion of the primary windings 20 is energized at a particular time. By varying which windings are energized, the electromotive force 32 generated between the magnetic field 40 of the stator 16 and the rotor magnetic field 44 of the rotor 14 generates an electromotive force 32 that rotates the rotor 14 relative to the stator 16. In various embodiments of the apparatus, energizing at least a portion of the axial coil assembly 24 can help modify the rotor magnetic field 44 generated by the rotor 14. In addition, by energizing only a portion of the secondary windings 28 of the axial coil assembly 24, the rotor magnetic field 40 generated by the rotor 14 can be increased in a particular region compared to other regions. Thus, a sequence of energizing different secondary windings 28 of the axial coil assembly 24 can be used to produce different rotational effects of the electromotive force 32 generated between the stator 16 and the rotor 14. These effects may take the form of one or more of the tactile components 152 described above. Other effects of activating only a portion of the secondary winding 28 may include an increase in torque 198, an increase in the rotational speed of the rotor 14, a wide variety of progressive motions of the rotor 14, and other similar rotational effects.

[0028] Within the hybrid stepping motor 12, multiple rotor teeth 64 defined on the outer circumference 90 of the rotor 14 magnetically interact with the poles 170 of the stator 16. Typically, the poles 170 of the stator 16 include multiple stator teeth 66 that operate to selectively align with the rotor teeth 64 of the rotor 14. By energizing only the poles 170 of the stator 16 or a portion of the primary winding 20, while simultaneously acting only a portion of the secondary coils of the axial coil assembly 24, the progressive motion of the rotor 14 can be modified to be in large or small steps relative to the stator 16.

[0029] In an exemplary embodiment where opposing secondary windings 28 of the axial coil assembly 24 are energized, the rotor magnetic field 44 relative to the rotor 14 may exist only on the opposing sides 180 of the rotor 14. In such an embodiment, only a portion of the rotor teeth 64 defined within the outer circumference 90 of the rotor 14 can be magnetically energized. These magnetically energized rotor teeth 64 can then be attracted to specific energized poles 170 of the stator 16. This rotational movement between the rotor 14 and the stator 16 may be greater than the distance between the individual rotor teeth 64 of the rotor 14 and the stator teeth 66 of the stator 16. Thus, while a conventional stepping motor can only rotate according to full steps or possibly half steps, energizing a portion of the secondary windings 28 of the axial coil assembly 24 can produce a configuration of the hybrid stepping motor 12 that provides double steps, quadruple steps, or smaller fractional steps within the hybrid stepping motor 12. As the name suggests, a double-step configuration can be created by having the teeth of the rotor 14 attracted to all the other teeth of the stator 16. Similarly, a quadruple step of the rotor 14 may indicate that the teeth of the rotor 14 are attracted to every other tooth of the stator 16. Additional step configurations can be generated via the hybrid stepping motor 12 by energizing various combinations of the windings of the stator 16 and the secondary windings 28 of the axial coil assembly 24.

[0030] As described above, torque 198, speed, gradual rotation, and other factors can be modified by selectively energizing the secondary winding 28 of the axial coil assembly 24 using the windings of the stator 16 and secondary winding 28 of the axial coil assembly 24.

[0031] Depending on the various aspects of the device, the hybrid stepping motor 12 described herein can be used in a variety of devices. Such devices include, but are not limited to, vehicle and instrument selector dials 150, robotic applications, disk drives, electric toys, encoders, and other similar motor applications requiring precise positioning, high speed, and variable torque requirements.

[0032] Referring to Figures 1-15, various embodiments of the bipolar hybrid stepping motor 12 have been described, but a method 400 for operating the bipolar hybrid stepping motor 12 incorporating one embodiment of the axial coil assembly 24 is disclosed. According to method 400, step 402 includes energizing the windings of the stator 16 so that the rotor 14 of the electric motor 10 is configured to act selectively and rotationally relative to the stator 16. According to method 400, step 404 includes generating a first magnetic component 190 of the rotor 14 via the axial coil assembly 24 (shown in Figure 8). As described above, the first magnetic component 190 can be generated by the axial coil assembly 24 alone. In such embodiments, supplying a second current 22 to the axial coil assembly 24 helps to energize the secondary winding 28. The secondary winding 28 sends magnetic flux 52 to the rotor 14, generating the rotor magnetic field 44 of the rotor 14. Alternatively, the first magnetic component 190 of the rotor 14 may be manufactured solely by magnetic members 60 located within the rotor 14, typically within individual rotor teeth 64 defined by the outer circumference 90 of the rotor 14. In this embodiment, the first magnetic component 190 may be defined by a secondary current 30 that is not supplied to the axial coil assembly 24. In other words, the first magnetic component 190 represents the axial coil assembly 24 in an idle state without secondary current 22, and the first magnetic component 190 is generated solely by the magnetic members 60 of the rotor 14. After the first magnetic component 190 is generated, the rotor 14 is operated using a first electromotive force 192 generated by energizing the primary winding 20 of the stator 16 (step 406). By energizing the primary winding 20 of the stator 16, the magnetic field 40 generated by the stator 16 interacts with the first magnetic component 190 to generate a first electromotive force. This first electromotive force typically helps to operate the rotor 14 in a rotational pattern. The operation of the rotor 14 can exhibit a stopping force 132 that prevents or slows down the rotation of the rotor 14 relative to the stator 16. According to method 400, step 408 may include modifying the secondary current 30 to the axial coil assembly 24.As described above, the secondary current 30 supplied to the axial coil assembly 24 can modify the magnetic flux 52 supplied to the rotor 14 and also modify the rotor magnetic field 44 generated by the rotor 14. Again, modifying the current 22 helps to generate a second magnetic component 194 (shown in Figure 9) of the rotor 14 via the modified current 22 of the axial coil assembly 24 (step 410). Again, when the secondary current 30 is modified, the first magnetic component 190 is typically different from the second magnetic component 194. This change between the first and second magnetic components 190, 194 typically generates a second electromotive force 196, which results in a modification of the amount of torque 198 that can be generated by the rotor 14 acting relative to the stator 16. According to method 400, step 412 includes operating the rotor 14 using a second electromotive force 196 generated by the energized primary winding 20 of the stator 16 and a second magnetic component 194 of the rotor 14 generated via a modified secondary current 30 supplied to the axial coil assembly 24.

[0033] As illustrated in Figures 1-15, one or more controllers 210 can be used to supply appropriate currents 22 and / or secondary currents 30 to the primary winding 20 and secondary winding 28, respectively. Furthermore, one or more controllers 210 can be configured to communicate with positioning sensors 136, which are responsible for monitoring the rotational position 134 of the rotor 14 relative to the stator 16. The hybrid stepping motor 12 can be operated using the controllers 210, the currents 22 and secondary currents 30, and the positioning sensors. In this way, the controllers 210 can be used to adjust the currents 22 and secondary currents 30 and generate speed, torque 198, step size, various tactile components 152, and other similar changes that can be generated between the rotor 14 and stator 16. In addition, the controllers 210 can be configured to communicate with positioning sensors to monitor when it is necessary to implement changes or modulation of the currents 22 and / or secondary currents 30 in order to change one of the output components of the hybrid stepping motor 12.

[0034] Depending on the various embodiments of the device, the number of secondary windings 28 defining the axial coil assembly 24 may vary depending on the specific design of the motor. As illustrated in Figure 2, eight posts 110 are included, and the secondary windings 28 are wound around the various posts 110 of the axial coil assembly 24. It is conceivable that more or fewer posts 110 can be included in the axial coil assembly 24. Also, the number of posts 110 included in the axial coil assembly 24 may or may not match the number of poles 170 included in the stator 16. Typically, the number of posts 110 included in the axial coil assembly 24 is different from the number of poles 170 of the stator 16. This difference in the configuration of the axial coil assembly 24 and the poles 170 of the stator 16 helps to generate the electromotive force 32 that acts on the rotor 14 relative to the stator 16.

[0035] As illustrated in Figures 2-3, the positioning of the posts 110 of the axial coil assembly 24 is typically such that there is a minimum space 220 between the posts 110 and the end 26 of the rotor 14. This close positioning helps maximize the magnetic flux 52 from the axial coil assembly 24 to the rotor 14, which helps generate the magnetic components 42 of the rotor 14 for operating the electric motor 10.

[0036] As illustrated in Figures 4 and 5, the configuration of the bipolar hybrid stepping motor 12 disclosed herein may include separate rotor cups 230 defining alternating rotor teeth 64 defined within the outer circumference 90 of each rotor cup 230. These rotor cups 230 can be separated into two ends 26 such that the rotor cup 230 at one end 26 generates the negative pole 102 of the rotor 14 and the rotor cup 230 at the other end 26 generates the positive pole 104. According to various embodiments of the apparatus, in certain configurations, the use of an axial coil assembly 24 can produce different effects with respect to the rotor 14. One such effect may be a change in the polarity of each of the secondary coils of the axial coil assembly 24. By changing the polarity of each of the secondary windings 28, the polarity of the rotor 14 can be switched so that the positive and negative poles 104, 102 of the rotor 14 can be alternately switched back and forth depending on the direction of the secondary current 30 supplied to the secondary windings 28 of the axial coil assembly 24.

[0037] Therefore, it should be understood that changes and modifications can be made to the aforementioned structure without departing from the concept of the present invention. Furthermore, it should be understood that such concepts are intended to be covered by the following claims unless those claims in language expressly state otherwise.

Claims

1. A stator having a primary winding, wherein the stator and the primary winding are arranged within a housing, A rotor having a magnetic component, wherein the rotor is rotatable relative to the stator, An axial coil assembly disposed within the housing, located at both ends of the rotor, and having secondary windings, At least a portion of the magnetic components of the rotor is generated by the energized axial coil assembly, and the energized state includes the axial coil assembly which generates electromagnetic communication between the rotor and the stator. A bipolar hybrid stepping motor in which the magnetic component of the rotor is partially defined by a magnetic member disposed within the rotor.

2. The bipolar hybrid stepping motor according to claim 1, wherein when the axial coil assembly is idle, the magnetic member generates the entire magnetic component of the rotor.

3. A stator having a primary winding energized by a primary current, A rotor that can rotate relative to the stator, wherein the stator extends around the rotor to determine the internal space in which the rotor operates, The rotor includes an axial coil assembly located at both ends of the rotor, positioned between the rotor's drive shaft and the rotor's outer edge, having a secondary winding selectively energized by a secondary current, and having a fixed axial position relative to the stator. When at least the secondary winding is energized, the rotor is in electromagnetic communication with the stator, and when the primary winding and the secondary winding are energized, the rotor is in electromagnetic communication with the stator via an electromotive force that causes the rotor to rotate. The energization of the primary winding and the secondary winding defines an electromotive force that selectively fixes the rotor to the stator, When the primary winding and the secondary winding are energized, the rotor is in electromagnetic communication with the stator via an electromotive force that selectively operates the rotor relative to the stator. An electric motor assembly in which the rotor and stator are not in electromagnetic communication when the axial coil assembly is in an electrically idle state.

4. A stator having a primary winding, wherein the stator and the primary winding are arranged within a housing, A rotor having a magnetic component, wherein the rotor is rotatable relative to the stator, An axial coil assembly disposed within the housing, located at both ends of the rotor, and having secondary windings, At least a portion of the magnetic components of the rotor is generated by the energized axial coil assembly, and the energized state includes the axial coil assembly which generates electromagnetic communication between the rotor and the stator. The axial coil assembly includes a first set of posts located at the first end of the rotor and a second set of posts located at the second end of the rotor, wherein the axial position of the axial coil assembly is fixed within the housing, in a bipolar hybrid stepping motor.

5. This involves energizing the windings of the stator so that the rotor rotates relative to the stator, The first magnetic component of the rotor is generated via an axial coil assembly, The rotor is operated using the first electromotive force generated by the energized windings of the stator and the first magnetic component of the rotor, To correct the current to the axial coil assembly, The process involves generating the second magnetic component of the rotor via the modified current of the axial coil assembly, wherein the first magnetic component is generated differently from the second magnetic component. A method for operating a bipolar hybrid stepping motor, comprising operating the rotor using a second electromotive force generated by the energized windings of the stator and the second magnetic component of the rotor.

6. The method according to claim 5, wherein the first magnetic component is defined by the magnetic members of the rotor and the axial coil assembly, which are electrically idle.

Images