EP4669948A1

EP4669948A1 - LOW-VOLTAGE COIL FOR COLLAR WIRE WINDING

Info

Publication number: EP4669948A1
Application number: EP23710580.4A
Authority: EP
Inventors: Gretchen Marie CONLEY; Anthony William Pankratz
Original assignee: Micro Motion Inc
Current assignee: Micro Motion Inc
Priority date: 2023-02-21
Filing date: 2023-02-21
Publication date: 2025-12-31
Also published as: CN120693507A; WO2024177624A1

Abstract

A bobbin (272c, 1072c, 1172c, 1372c) for a low stress coil wire winding is provided. The bobbin (272c, 1072c, 1172c, 1372c) comprises a coil groove (272c-03, 1072c-03, 1172c-03, 1372c-03) extending between a proximate end and a distal end of the bobbin (272c, 1072c, 1172c, 1372c) and a wire guide head (272c-05, 1072c-05, 1172c-05, 1372c-05) at the proximate end. The wire guide head (272c-05, 1072c-05, 1172c-05, 1372c-05) comprises one or more wire guide grooves (272c-09, 272c-12, 1072c-09, 1072c-12, 1172c-09, 1372c-09, 1372c-12) extending through the wire guide head (272c-05, 1072c-05, 1172c-05, 1372c-05) to the coil groove (272c-03, 1072c-03, 1172c-03, 1372c-03) and the one or more wire guide grooves (272c-09, 272c-12, 1072c- 09, 1072c-12, 1172c-09, 1372c-09, 1372c-12) are curvilinear.

Description

A BOBBIN FOR LOW STRESS COIL WIRE WINDING

TECHNICAL FIELD

The embodiments described below relate to bobbins for coil wires and, more particularly, to a bobbin for low stress coil wire winding.

BACKGROUND

Coil transducers typically include a coil wire that is disposed about a bobbin with a hollow inner portion. A magnet moves in and out of the hollow inner portion of the bobbin to generate a current. A magnitude of the current is proportional to a velocity of the magnet and a strength of a magnetic field provided by the magnet. Conversely, a current supplied to the coil can induce a magnetic field. The magnetic field of the coil can interact with the magnetic field of the magnet to induce opposing forces on the coil wire and the magnet. Accordingly, the coil transducers can be used to convert electrical signals into a mechanical force and/or convert a mechanical velocity into an electrical signal.

A coil wire winding machine may wrap the coil wire about the bobbin. The coil wire winding machine may initiate a coil winding operation by inserting the coil wire into a coil wire feed groove. The coil wire feed groove may be designed to limit circumferential movement of the coil wire while the coil wire winding machine circumferentially wraps the coil wire about the bobbin. As can be appreciated, the coil winding operation can induce stress in the coil wire.

However, some industries may require significant accuracy and reliability from the coil transducers or, in particular, the coil wire wrapped around the bobbin. For example, some applications may require that the coil wire have a resistance that is within a certain specification over a wide range of temperature. Others may require that the coil wire not fail during significant mechanical stress, such as vibrations, shock, or the like. The stress induced by the coil winding operation can affect the accuracy and reliability of the coil transducer. Accordingly, there is a need for a low stress coil wire winding and, in particular, a bobbin for low stress coil wire winding. SUMMARY

A bobbin for low stress coil wire winding is provided. According to an embodiment, the bobbin comprises a coil groove extending between a proximate end and a distal end of the bobbin and a wire guide head at the proximate end, the wire guide head comprising one or more wire guide grooves extending through the wire guide head to the coil groove. The one or more wire guide grooves are curvilinear.

A coil transducer having a bobbin for low stress coil wire winding is provided. According to an embodiment, the coil transducer comprising a magnet assembly, and a coil assembly, the coil assembly comprising a coil and a bobbin according to the foregoing, the bobbin being disposed within the coil.

A sensor assembly having a bobbin for a low stress coil wire winding is provided. According to an embodiment, the sensor assembly comprises a conduit and an opposing body and a coil transducer according to the foregoing mechanically coupled to the conduit and the opposing body.

A method of forming a bobbin for a low stress coil wire winding is provided. According to an embodiment, the method comprises forming a coil groove extending between a proximate end and a distal end of the bobbin and forming a wire guide head at the proximate end, wherein forming the wire guide head comprises forming one or more wire guide grooves extending through the wire guide head to the coil groove, wherein the one or more wire guide grooves are curvilinear.

A method of forming a coil transducer is provided. According to an embodiment, the method comprises providing a bobbin according to one of the foregoing, disposing a coil wire in one of the one or more wire guide grooves, and winding the coil wire about the bobbin and into the coil groove, wherein the coil wire in the one of the one or more wire guide grooves is curvilinear.

ASPECTS

According to an aspect, a bobbin for a low stress coil wire winding comprises a coil groove extending between a proximate end and a distal end of the bobbin, and a wire guide head at the proximate end, the wire guide head comprising one or more wire guide grooves extending through the wire guide head to the coil groove. The one or more wire guide grooves are curvilinear. Preferably, the coil groove extending between the proximate end and the distal end comprises the coil groove extending between a coil groove lip at the distal end of the bobbin and a coil groove shoulder at the proximate end of the bobbin.

Preferably, a radial distance of the coil groove lip at the distal end of the bobbin and a radial distance of the coil groove shoulder at the proximate end of the bobbin are substantially equal.

Preferably, a radial distance of the wire guide head is greater than the radial distance of the coil groove shoulder.

Preferably, the wire guide head comprises a wire guide head chamfer extending from the radial distance of the wire guide head to the radial distance of the coil groove shoulder.

Preferably, the one or more wire guide grooves extending through the wire guide head to the coil groove comprises at least one of the one or more wire guide grooves radially sloping from a radial distance of the wire guide head to a radial distance of the coil groove, and the one or more wire guide grooves perimetrically curving from the proximate end of the bobbin to the coil groove.

Preferably, the one or more wire guide grooves comprises a wire guide ramp, wherein the radial distance of the wire guide head comprises a radial distance of the wire guide ramp.

Preferably, the one or more wire guide grooves comprise at least one of a wire guide inner wall and a wire guide outer wall, the wire guide outer wall being configured to retain and bend the coil wire.

Preferably, the wire guide head comprises a first wire bend guide and a second wire bend guide, the first wire bend guide and the second wire bend guide respectively comprising one of the one or more wire guide grooves.

Preferably, the first wire bend guide and the second wire bend guide have a radial distance that is greater than a radial distance of a wire guide backing disposed between the first wire bend guide and the second wire bend guide.

According to an aspect, a coil transducer having a bobbin for low stress coil wire winding, the coil transducer comprising a magnet assembly, and a coil assembly, the coil assembly comprising a coil and a bobbin according to the foregoing, the bobbin being disposed within the coil. According to an aspect, a sensor assembly having a bobbin for a low stress coil wire winding comprising a conduit and an opposing body, and a coil transducer according to the foregoing mechanically coupled to the conduit and the opposing body.

Preferably, the opposing body comprises one of a conduit, a reference body, and a balance bar.

According to an aspect, a method of forming a bobbin for a low stress coil wire winding comprising forming a coil groove extending between a proximate end and a distal end of the bobbin and forming a wire guide head at the proximate end, wherein forming the wire guide head comprises forming one or more wire guide grooves extending through the wire guide head to the coil groove, wherein the one or more wire guide grooves are curvilinear.

Preferably, forming the coil groove extending between the proximate end and the distal end comprises forming the coil groove extending between a coil groove lip at the distal end of the bobbin and a coil groove shoulder at the proximate end of the bobbin.

Preferably, forming the one or more wire guide grooves extending through the wire guide head to the coil groove comprises at least one of forming the one or more wire guide grooves to radially slope from the radial distance of the wire guide head to a radial distance of the coil groove, and forming the one or more wire guide grooves to perimetrically curve from the proximate end of the bobbin to the coil groove.

Preferably, forming the one or more wire guide grooves comprises forming a wire guide ramp, wherein the radial distance of the wire guide head comprises a radial distance of the wire guide ramp. Preferably, forming the one or more wire guide grooves comprises forming at least one of a wire guide inner wall and a wire guide outer wall, the wire guide outer wall being configured to retain and bend the coil wire.

Preferably, forming the wire guide head comprises forming a first wire bend guide and a second wire bend guide, the first wire bend guide and the second wire bend guide respectively comprising one of the one or more wire guide grooves.

According to an aspect, a method of forming a coil transducer comprises providing a bobbin according to one of the foregoing, disposing a coil wire in one of the one or more wire guide grooves, and winding the coil wire about the bobbin and into the coil groove, wherein the coil wire in the one of the one or more wire guide grooves is curvilinear.

Preferably, the method further comprises disposing the coil wire in another one of the one or more wire guide grooves, wherein the coil wire in the another one of the one or more wire guide grooves is curvilinear.

BRIEF DESCRIPTION OF THE DRAWINGS

The same reference number represents the same element on all drawings. It should be understood that the drawings are not necessarily to scale.

FIG. 1 shows a vibratory meter 5 including a bobbin for a low stress coil wire winding.

FIGS. 2 and 3 show a sensor assembly portion 200 that includes a coil transducer 270 coupled to the conduits 130, 130’ described with reference to FIG. 1.

FIG. 4 shows a prior art coil bobbin 12c.

FIGS. 5-9 show more detailed views of the bobbin 272c described with reference to FIGS. 2 and 3.

FIG. 10 shows an alternative bobbin 1072c for low stress coil wire winding.

FIGS. 11 and 12 show an alternative bobbin 1172c for low stress coil wire winding. FIGS. 13 and 14 show an alternative bobbin 1372c for low stress coil wire winding.

FIG. 15 shows a method 1500 of forming a bobbin for low stress coil wire winding.

FIG. 16 shows a method 1600 of forming a coil transducer including a bobbin for low stress coil wire winding.

DETAILED DESCRIPTION

FIGS. 1 - 16 and the following description depict specific examples to teach those skilled in the art how to make and use the best mode of embodiments of a bobbin for low stress coil wire winding. For the purpose of teaching inventive principles, some conventional aspects have been simplified or omitted. Those skilled in the art will appreciate variations from these examples that fall within the scope of the present description. Those skilled in the art will appreciate that the features described below can be combined in various ways to form multiple variations of the bobbin for low stress coil wire winding. As a result, the embodiments described below are not limited to the specific examples described below, but only by the claims and their equivalents.

FIG. 1 shows a vibratory meter 5 including a bobbin for a low stress coil wire winding. As shown in FIG. 1, the vibratory meter 5 comprises a sensor assembly 10 and meter electronics 20. The sensor assembly 10 responds to mass flow rate and density of a process material. The meter electronics 20 is connected to the sensor assembly 10 via leads 100 to provide density, mass flow rate, and temperature information over port 26, as well as other information.

The sensor assembly 10 includes a pair of manifolds 150 and 150', flanges 103 and 103' having flange necks 110 and 110', a pair of parallel conduits 130 and 130', driver 180, resistive temperature detector (RTD) 190, and a pair of pick-off sensors 1701 and 170r. Conduits 130 and 130' have two essentially straight inlet legs 131, 131' and outlet legs 134, 134', which converge towards each other at conduit mounting blocks 120 and 120'. The conduits 130, 130' bend at two symmetrical locations along their length and are essentially parallel throughout their length. Brace bars 140 and 140' serve to define the axis W and W' about which each conduit 130, 130’ oscillates. The legs 131, 131' and 134, 134' of the conduits 130, 130' are fixedly attached to conduit mounting blocks 120 and 120' and these blocks, in turn, are fixedly attached to manifolds 150 and 150'. This provides a continuous closed material path through sensor assembly 10.

When flanges 103 and 103', having holes 102 and 102' are connected, via inlet end 104 and outlet end 104' into a process line (not shown) which carries the process material that is being measured, material enters inlet end 104 of the meter through an orifice 101 in the flange 103 and is conducted through the manifold 150 to the conduit mounting block 120 having a surface 121. Within the manifold 150 the material is divided and routed through the conduits 130, 130'. Upon exiting the conduits 130, 130', the process material is recombined in a single stream within the block 120’ having a surface 121’ and the manifold 150' and is thereafter routed to outlet end 104' connected by the flange 103' having holes 102' to the process line (not shown).

The conduits 130, 130' are selected and appropriately mounted to the conduit mounting blocks 120, 120' so as to have substantially the same mass distribution, moments of inertia and Young's modulus about bending axes W— W and W'— W', respectively. These bending axes go through the brace bars 140, 140'. Inasmuch as the Young's modulus of the conduits change with temperature, and this change affects the calculation of flow and density, RTD 190 is mounted to conduit 130' to continuously measure the temperature of the conduit 130’. The temperature of the conduit 130’ and hence the voltage appearing across the RTD 190 for a given current passing therethrough is governed by the temperature of the material passing through the conduit 130’. The temperature dependent voltage appearing across the RTD 190 is used in a well-known method by the meter electronics 20 to compensate for the change in elastic modulus of the conduits 130, 130' due to any changes in conduit temperature. The RTD 190 is connected to the meter electronics 20 by lead 195.

Both of the conduits 130, 130' are driven by driver 180 in opposite directions about their respective bending axes W and W' and at what is termed the first out-of- phase bending mode of the vibratory meter. Although two conduits 130, 130’ are shown, any suitable arrangement may be employed. For example, a single conduit may be employed where the driver 180 is coupled to the conduit 130 and an opposing body. An opposing body may or may not opposingly oscillate relative to the conduit 130. An opposing body may include a reference body, such as a case, a balance bar, or the like. In these and other examples, the driver 180 may comprise any one of many well-known arrangements, such as a magnet mounted to the conduit 130' and an opposing coil mounted to the conduit 130 and through which an alternating current is passed for vibrating both conduits 130, 130’. A suitable drive signal 185 is applied by the meter electronics 20, via a lead, to the driver 180. Accordingly, the vibratory meter 5 or, more particularly, the sensor assembly 10, may be viewed as a symmetrically oscillating device, such as the symmetrically oscillating device 1 described above.

The meter electronics 20 receives the RTD temperature signal on lead 195, and sensor signals 165 appearing on leads 100 carrying left and right sensor signals 1651, 165r, respectively. The meter electronics 20 produces the drive signal 185 appearing on the lead to driver 180 and vibrate conduits 130, 130'. The meter electronics 20 processes the left and right sensor signals 1651, 165r and the lead 195 carrying an RTD signal to compute the mass flow rate and the density of the material passing through sensor assembly 10. This information, along with other information, is applied by meter electronics 20 over port 26 as a signal.

As discussed above, the sensor assembly 10 includes the driver 180 and the pair of pick-off sensors 1701 and 170r. The driver 180 and part of pick-off sensors 1701 and 170r can be coil transducers that include a bobbin for low stress coil wire winding, as is explained in more detail in the following.

FIGS. 2 and 3 show a sensor assembly portion 200 that includes a coil transducer 270 coupled to the conduits 130, 130’ described with reference to FIG. 1. The coil transducer 270 may be the pickoff sensors 1701, 170r described above, although the coil transducers 270 may be any suitable transducer that includes a bobbin for low stress coil wire winding. For example, the coil transducer 270 may be the driver 180 described above with reference to FIG. 1.

The coil transducer 270 is mechanically coupled to the conduits 130, 130’. The coil transducer 270 is mechanically coupled to the conduits 130, 130’ with the brackets 220, 220’. With more particularity, a coil assembly 270c is mechanically coupled to a first bracket 220 which is mechanically coupled to a first conduit 130 and the magnet assembly 270m is mechanically coupled to the second bracket 220’ which is mechanically coupled to the second conduit 130’. The coil assembly 270c is comprised of a bobbin 272c, an insert 274c, and a coil 276c disposed about the bobbin 272c. The magnet assembly 270m is comprised of a magnet 272m and a magnet keeper 274m.

The brackets 220, 220’ may be mechanically coupled to the conduits 130, 130’ by brazing, welding, single piece forging, and/or or any other suitable means. As shown in FIG. 2, the brackets 220, 220’ are affixed to the conduits 130, 130’ with brazing. The coil transducer 270 is shown as being mechanically coupled to the brackets 220, 220’ using a screw as a fastener. However, alternative pickoff sensors may be affixed to alternative brackets by any suitable means, such as brazing, welding, fastening, and/or the like.

The coil transducer 270 may be a displacement sensor comprised of two relatively positioned portions that enable the coil transducer 270 to determine a relative displacement value between the two portions. As used herein, the term “displacement value” encompasses any displacement related values, such as distance, velocity, acceleration, etc. As shown in FIG. 2, the two portions of the coil transducer 270 are a coil assembly 270c and a magnet assembly 270m.

The coil assembly 270c and the magnet assembly 270m are shown as being symmetrically disposed between the conduits 130, 130’ but with some overlap due to a complementary and non-interfering interface. With more particularity, the coil assembly 270c has a cylindrical interface portion that has a smaller diameter than a cylindrical interface portion of the magnet assembly 270m. Accordingly, the coil assembly 270c extends into the magnet assembly 270m while the magnet assembly 270m encompasses the coil assembly 270c.

The coil assembly 270c is shown as comprising a bobbin 272c and an insert 274c that are mechanically coupled to each other. With more particularity, the bobbin 272c is affixed to the insert 274c. As shown in FIG. 2, the bobbin 272c is over-molded onto the insert 274c. That is, the bobbin 272c may be comprised of a non-conductive substance, such as a polymer, ceramic, or the like, that is over-molded onto the insert 274c. Although not shown in FIG. 2, the coil assembly 270c includes a coil wrapped about the bobbin 272c. The coil may carry a current due to a magnetic field of the magnet assembly 270m.

The magnet assembly 270m is shown as comprising a magnet 272m and a magnet keeper 274m. The magnet 272m and the magnet keeper 274m are mechanically coupled to each other. With more particularity, the magnet 272m is affixed to the magnet keeper 274m. The magnet 272m and the magnet keeper 274m may be mechanically affixed to each other using any suitable means, such as adhesive, press fit, fastening features, or the like. The magnet 272m may provide a magnetic field that is shaped and condensed by the magnet keeper 274m. Accordingly, the magnet keeper 274m may be comprised of a paramagnetic material, although any suitable material capable of shaping and/or condensing the magnetic field provided by the magnet 272m may be employed. Although the coil assembly 270c and the magnet assembly 270m are respectively shown as comprised of two different parts, other coil and magnet assemblies may respectively be comprised of more or fewer parts. For example, an alternative coil assembly may be comprised of a single integral piece of material that is forged, machined, or the like. Alternatively, other coil assemblies may be comprised of three or more parts.

The coil and magnet assembly 270c, 270m respectively move with the conduits 130, 130’. Accordingly, the coil assembly 270c and the magnet assembly 270m move to and from each other. When the conduits 130, 130’ opposingly oscillate, the coil and magnet assembly 270c, 270m will also opposingly oscillate. The opposing oscillation of the coil and magnet assembly 270c, 270m can therefore cause a magnetic field of the magnet assembly 270m to vary in the coil of the coil assembly 270c. As a result, the coil of the coil assembly 270c may provide a current that is proportional to a relative velocity of the coil and magnet assembly 270c, 270m. The current can be received by a meter electronics, such as the meter electronics 20 described above, to determine a measured value.

The shape and density of the insert 274c may be selected during design, prototyping, fabrication, or the like, although any suitable means may be employed to select the shape and density of the insert 274c. The insert 274c is shown as having a cylindrical shape with an internal threaded portion that interfaces with a bolt. The bolt provides a compressive force to the insert 274c and the first bracket 220. Accordingly, the insert 274c and the first bracket 220 are compressed together. As shown in FIG. 2, the insert 274c includes a retaining groove that interfaces with a retaining tongue of the bobbin 272c. Accordingly, the bobbin 272c is also compressed towards the first bracket 220, as shown in FIG. 2, and the bobbin 272c does not abut the first bracket 220. The bobbin 272c described above is different than prior art bobbins. The differences between the bobbin 272c and the prior art bobbins are described in the following, beginning with a description of a prior art bobbin with reference to FIG. 4.

Prior art bobbins

FIG. 4 shows a prior art coil bobbin 12c. As shown in FIG. 4, the bobbin 12c has a hollow cylindrical shape with lips on each end. The lips and outer surface of the bobbin 12c form a coil groove 12cg. Additionally, one of the lips includes wire slots 12cw. The wire slots 12cw are used during assembly to retain a coil wire as a wire winding tool winds the coil wire about the coil groove 12cg. As can be seen in FIG. 4, the wire slots 12cw are parallel with and coplanar with the outer surface of the coil groove 12cg. The wire slots 12cw is also entirely linear. That is, inner and outer walls as well as a floor of the wire slots 12cw do not have a radius of curvature. The entirely linear wire slots 12cw therefore end at a sharp corner of the lips of the bobbin 12c. This causes a coil wire to be pressed against the sharp corner where the wire slots 12cw meet the coil groove 12cg. As a result, the coil wire may experience significant localized stress, or stress concentration, and, therefore, may have a strain that affects mechanical and electrical properties of the coil wire. Additionally, or alternatively, the coil wire may have stress fractures, microfractures, fatigue, or the like. The localized stress may also cause the coil wire to fail, such as severing the wire, during winding.

Bobbins with curvilinear wire guide grooves

The following describes bobbins that include wire guide grooves that are curvilinear, in contrast to entirely linear wire slots 12cw of the bobbin 12c described with reference to FIG. 4. For example, the wire guides may radially slope from a radial distance of a wire guide head of a bobbin to a radial distance of the coil groove. Additionally, or alternatively, the wire guide grooves may perimetrically (along a perimeter of the bobbin) curve from an end of the wire guide head to the coil groove. Due to the wire guide grooves being curvilinear, localized stress in the coil wire may be significantly less than the coil wire wound about the bobbin 12c shown in FIG. 4.

FIGS. 5-9 show more detailed views of the bobbin 272c described with reference to FIGS. 2 and 3. In FIGS. 5-9, the insert 274c and the coil 276c are not shown for clarity. As shown, the bobbin 272c has a hollow cylindrical shape that is substantially symmetric about a coil bobbin centerline CL272C. As is described in more detail in the following, the bobbin 272c and/or a wire winding tool, may be rotated about the coil bobbin centerline CL272C so as to form the coil 276c described above.

The bobbin 272c is shown in FIG. 5 as including a coil groove lip 272c-01 and a coil groove shoulder 272c-02. Between the coil groove lip 272c-01 and the coil groove shoulder 272c-02 is a coil groove 272c-03. The coil groove shoulder 272c-02 is shown as being a feature of the bobbin base 272c-04. As can be appreciated, the coil groove lip 272c-01, coil groove shoulder 272c-02, and the coil groove 272c-03 are substantially symmetric about the coil bobbin centerline CL272C. That is, they comprise a surface extending perimetrically at an orthogonally radial symmetric distance about the coil bobbin centerline CL272C. Where a bobbin is cylindrical, such as the bobbin 272c shown in FIG. 5, perimetrical may alternatively be referred to as circumferential.

The bobbin base 272c-04 also includes a wire guide head 272c-05 that extends radially from the bobbin base 272c-04. The wire guide head 272c-05, which is shown in FIG. 5 and with more detail in FIGS. 6-8, may be used to by a wire wrapping machine to wrap the coil wire about the bobbin 272c and into the coil groove 272c-03. Referring to FIG. 5, it can be appreciated that the wire guide head 272c-05 extends radially from a perimetric surface of a bobbin base 272c-04. The bobbin base 272c-04 is shown as having a cylindrical shape with a base chamfer surface 272c-06. As can be seen, the base chamfer surface 272c-06 extends from an outer portion of the bobbin base 272c-04 to the coil groove shoulder 272c-02 with a decreasing radial distance. Accordingly, the base chamfer surface 272c-06 forms a sloped or ramped surface in the bobbin base 272c-04 extending towards the coil groove 272c-03.

As shown in FIGS. 5-8, the wire guide head 272c-05 is comprised of a first coil winding guide 272c-07 and a second coil winding guide 272c-08. The first coil winding guide 272c-07 and the second coil winding guide 272c-08 may respectively be an ingress wire winding guide and an egress wire winding guide, although any suitable arrangement and/or terms may be employed. The first and second coil winding guides 272c-07, 272c-08 can capture and restrain in the circumferential direction the coil wire during a winding of the coil wire about the bobbin 272c.

In the more detailed views of FIG. 6-8, the first and second coil winding guides 272c-07, 272c-08 are shown as respectively being comprised of a first wire guide groove 272c-09 and a first wire bend guide 272c-10, and a second wire guide groove 272c-12 and a second wire bend guide 272c-13. A wire guide backing 272c-ll is disposed between the first wire bend guide 272c- 10 and the second wire bend guide 272c-13. The first wire guide groove 272c-09 is between and is partially defined by the first wire bend guide 272c-10 and the wire guide backing 272c-ll. Similarly, the second wire guide groove 272c- 12 is between and partially defined by the second wire bend guide 272c-13 and the wire guide backing 272c-ll.

As shown in FIGS. 7 and 8, the first wire guide groove 272c-09 is comprised of a first wire guide inner wall 272c-14, a first wire guide ramp 272c-16, and a first wire guide outer wall 272c-15. Similarly, the second wire guide groove 272c-12 is comprised of a second wire guide inner wall 272c- 17, a second wire guide ramp 272c- 19, and a second wire guide outer wall 272c- 18. The terms inner and outer may respectively refer to inner and outer surface regions of the wire guide head 272c-05 when used in terms of describing features of the wire guide head 272c-05. As can be appreciated, the first and second wire guide inner wall 272c- 14, 272c- 17, the first and second wire guide ramp 272c-16, 272c-19, and the first and second wire guide outer wall 272c-15, 272c-18 are comprised of curvilinear surfaces.

For example, the first and second wire guide outer wall 272c- 15, 272c- 18 are comprised of respectively symmetrical arcs that radially slope and perimetrically curve from an outer portion of the wire guide head 272c-05 to the coil groove shoulder 272c- 02. The perimetrical curve (e.g., a curve in a direction along a perimeter surface of the bobbin base 272c-04) of the first and second wire guide outer wall 272c- 15, 272c- 18 is illustrated by the side perspective of FIG. 7.

Accordingly, proximate the outer portion of the wire guide head 272c-05, the first and second wire guide outer wall 272c-15, 272c-18 extend from a direction that is approximately perpendicular a plane formed by the outer portion of the wire guide head 272c-05 to a direction that is substantially parallel to the coil groove shoulder 272c-02. The arc shape of the first and second wire guide outer wall 272c- 15, 272c- 18 does not have a constant radius of curvature but has an increasing radius of curvature as the first and second wire guide outer wall 272c- 15, 272c- 18 extends from the outer portion of the wire guide head 272c-05.

As can also be seen, the first and second wire guide outer wall 272c-15, 272c-18 have a significant length. For example, the first and second wire guide outer wall 272c- 15, 272c- 18 is several times greater than a width of the first and second wire guide ramp 272c-16, 272c-19. Accordingly, the first and second wire guide outer wall 272c-15, 272c- 18 is many more times greater than a width of any wire guided by the first and second wire guide groove 272c-09, 272c- 12.

As can be appreciated from FIGS. 5 and 6, the wire guide backing 272c- 11 does not extend from the bobbin base 272c-04 as much as the first and second wire bend guide 272c-10, 272c-13. With more particularity, the wire guide backing 272c-ll has a chamfer with, proximate the coil groove shoulder 272c-02, a radial distance that is the same as the base chamfer surface 272c-06. Additionally, proximate the coil groove shoulder 272c-02, the first and second wire bend guide 272c- 10, 272c- 13 extend from the bobbin base 272c-04 more than the wire guide backing 272c-ll.

Accordingly, during winding, a coil wire extending longitudinally (e.g., substantially parallel with the coil bobbin centerline CL272c) between the first wire bend guide 272c-10 and the second wire bend guide 272c-13 can be captured by the first wire bend guide 272c- 10 or the second wire bend guide 272c- 13 when the longitudinally aligned coil wire is displaced circumferentially about the coil bobbin centerline CL272C. After the coil wire is captured, a coil winding machine may press and/or pull the coil wire into the first wire guide groove 272c-09 or the second wire guide groove 272c- 12.

For example, FIG.8 shows portions of the coil 276c illustrated as double arrow ended lines. The arrows at the ends of the double arrow ended lines depict an exemplary tensile force applied to the illustrated portions of the coil 276c. The double arrow ended lines illustrate an exemplary location and disposition of a coil wire during winding. As shown in FIG. 8, the coil 276c is pressed against the first wire guide outer wall 272c-15 and the second wire guide outer wall 272c- 18 due to the tensile force depicted by the arrows. Additionally, one of the double arrow ended lines is disposed proximate the coil groove 272c-03 and the other of the double arrow ended lines is disposed proximate the base chamfer surface 272c-06, which may be due to ingress and egress of the coil 276c to and from the coil groove 272c-03.

In addition, FIG. 9 shows a side view of the bobbin 272c for low stress coil wire winding. In FIG. 9, the bobbin 272c is shown as being substantially symmetrically disposed about the coil bobbin centerline CL272C. The bobbin 272c is also shown as including the bobbin base 272c-04, coil groove shoulder 272c-02, coil groove 272c-03, and coil groove lip 272c-01 described above. The bobbin base 272c-04 includes the base chamfer surface 272c-06 that extends from an outside portion of the bobbin base 272c- 04 to the coil groove shoulder 272c-02. Also shown is the wire guide head 272c-05 which, due to the side view perspective, is shown as including the second wire bend guide 272c-13 and the wire guide backing 272c-ll. The second wire guide ramp 272c- 19 is shown as a dashed line.

Also shown are radial distances representing a distance of a feature on a surface of the bobbin 272c from the coil bobbin centerline CL272C. For example, an outer or most proximate portion of the bobbin base 272c-04 is shown as having a bobbin base radial distance r_Cb. The coil groove lip 272c-01 is shown as having a coil groove lip radial distance r_ci, which is shown as being a distance of a perimeter surface of the coil groove lip 272c-01 from the coil bobbin centerline CL272C. Similarly, the coil groove shoulder 272c-02 has a coil groove shoulder radial distance r_cs that is substantially equal to the coil groove lip radial distance r_ci. The coil groove 272c-03 is shown as having a coil groove radial distance r_cg, which is less than the coil groove shoulder radial distance r_cs and the coil groove lip radial distance r_ci. Additionally, the wire guide head 272c-05 is shown as having various radial distances. For example, the second wire bend guide 272c- 13 is shown as having a second bending guide radial distance r_Wbs and the wire guide backing 272c-l 1 is shown as having a wire guide backing radial distance r_WCs. The second wire bend guide 272c- 13 is shown as having a second bending guide chamfer radial distance rihc.

Although not explicitly referenced with reference characters in FIG. 9, when considering the wire guide backing 272c-l 1 as shown in FIGS. 5-9, it can be appreciated that a radial distance of the wire guide backing 272c- 11 proximate the coil groove shoulder 272c-02 is about equal with the coil groove shoulder radial distance r_cs. Similarly, although not explicitly referenced with a numeral in FIG. 9, a radial distance of an outer portion of the bobbin base is substantially the same as the wire guide backing radial distance r_wcs and a radial distance of an end of the second wire guide ramp 272c- 19 proximate the outer portion of the bobbin base. An end of the second wire guide ramp 272c- 19 proximate the coil groove shoulder 272c-02 has a radial distance substantially equal to the coil groove shoulder radial distance r_cs. As can also be appreciated from considering FIG. 9 with FIGS. 5-8, a first bending guide radial distance (not shown) is equal to the second bending guide radial distance r_Wbs. As can be appreciated from FIG. 9, the wire guide backing radial distance r_wcs is greater than a radial distance of the chamfer of the second wire bend guide 272c- 13 about a midpoint of the chamfer of the second wire bend guide 272c- 13. At ends of the chamfer of the second wire bend guide 272c-13, the radial distances of the second wire bend guide 272c- 13 are greater than a radial distance of the wire guide backing 272c- 11 from a common point on the coil bobbin centerline CL272C.

Accordingly, a coil wire (not shown) proximate the second wire bend guide 272c- 13 and extending in a direction substantially parallel to the coil bobbin centerline CL272C while moving perimetrically about the coil bobbin centerline CL272C, towards the wire guide backing 272c- 11 may be restrained from further movement by the wire guide backing 272c-ll. Additionally, if the coil wire is proximate the wire guide backing 272c- 11 and extending in a direction substantially parallel to the coil bobbin centerline CL272C while moving perimetrically about the coil bobbin centerline CL272C, towards the second wire bend guide 272c- 13 may be restrained from further movement by the second wire bend guide 272c- 13.

In addition, the second wire guide ramp 272c- 19 is shown to radially slope from the outer portion of the bobbin base 272c-04 to the coil groove 272c-03. With more specificity, the second wire guide ramp 272c- 19 radially slopes from the wire guide backing radial distance r_wcs to the coil groove radial distance r_cg. As can be seen, the radially sloping face of the second wire guide ramp 272c- 19 is curvilinear where the ends of the second wire guide ramp 272c- 19 are respectively substantially parallel with the outer portion of the bobbin base 272c-04 and the coil groove 272c-03. As a result, referring to FIGS. 8 and 9, a coil wire in the second wire guide groove 272c-12 may not be subjected to a stress, such as a bending stress, due to the second wire guide ramp 272c- 19.

The foregoing described bobbin 272c includes a wire guide head 272c-05 that includes a chamfer and first and second wire bend guide 272c- 10, 272c- 13 with relatively large surface areas. Other coil bobbins with alternative curvilinear wire guides may be employed, an example of which is described in the following. Alternative bobbin for low stress coil wire winding

FIG. 10 shows an alternative bobbin 1072c for low stress coil wire winding. As shown in FIG. 10, bobbin 1072c has a hollow cylindrical shape that is substantially symmetric about a coil bobbin centerline CLIO72C. The bobbin 1072c, or a wire winding tool, may be rotated about the coil bobbin centerline CLIO72C so as to form a coil similar to the coil 276c described above.

The bobbin 1072c is shown in FIG. 10 as including a coil groove lip 1072c-01 and a coil groove shoulder 1072c-02. Between the coil groove lip 1072c-01 and the coil groove shoulder 1072c-02 is a coil groove 1072c-03. The coil groove shoulder 1072c-02 is shown as being a feature of the bobbin base 1072c-04. As can be appreciated, similar to the bobbin 272c described above, the coil groove lip 1072c-01, coil groove shoulder 1072c-02, and the coil groove 1072c-03 are substantially symmetric about the coil bobbin centerline CLIO72C.

The bobbin base 1072c-04 also includes a wire guide head 1072c-05 that extends radially from the bobbin base 1072c-04. The wire guide head 1072c-05 may be used to wrap the coil wire about the bobbin 1072c in the coil groove 1072c-03. It can be appreciated from FIG. 10 that the wire guide head 1072c-05 extends radially from a perimetric surface of a bobbin base 1072c-04. The bobbin base 1072c-04 is shown as having a cylindrical shape with a base chamfer surface 1072c-06. As can be seen, the base chamfer surface 1072c-06 extends from an outer portion of the bobbin base 1072c- 04 to the coil groove shoulder 1072c-02 with a decreasing radial distance. Accordingly, the base chamfer surface 1072c-06 forms a sloped or ramped surface extending towards the coil groove 1072c-03.

As shown in FIG. 10, the wire guide head 1072c-05 is comprised of a first wire winding guide 1072c-07 and a second wire winding guide 1072c-08. The first wire winding guide 1072c-07 and the second wire winding guide 1072c-08 may respectively be an ingress wire winding guide and an egress wire winding guide, although any suitable arrangement and/or terms may be employed. The first and second wire winding guide 1072c-07, 1072c-08 can capture and restrain in the circumferential direction the coil wire during a winding of the coil wire about the bobbin 1072c.

In FIG. 10, the first and second wire winding guide 1072c-07, 1072c-08 are shown as respectively being comprised of a first wire guide groove 1072c-09 and a first wire bend guide 1072c- 10, and a second wire guide groove 1072c- 12 and a second wire bend guide 1072c-13. A wire guide backing 1072c-l 1 is disposed between the first wire bend guide 1072c-10 and the second wire bend guide 1072c-13. The first wire guide groove 1072c-09 is between and is at least partially defined by the first wire bend guide 1072c- 10 and the wire guide backing 1072c-ll. Similarly, the second wire guide groove 1072c-12 is between and is at least partially defined by the second wire bend guide 1072c- 13 and the wire guide backing 1072c-ll.

As shown in FIG. 10, the first wire guide groove 1072c-09 is comprised of a first wire guide inner wall 1072c-14, a first wire guide ramp 1072c-16, and a first wire guide outer wall 1072c-15. Similarly, the second wire guide groove 1072c-12 is comprised of a second wire guide inner wall 1072c-17, a second wire guide ramp 1072c-19, and a second wire guide outer wall 1072c-18. As can be appreciated, the first and second wire guide inner wall 1072c-14, 1072c-17, the first and second wire guide ramp 1072c-16, 1072c-19, and the first and second wire guide outer wall 1072c-15, 1072c-18 are comprised of curvilinear surfaces.

For example, the first and second wire guide outer wall 1072c-15, 1072c-18 are comprised of symmetrical arcs that curve from an outer portion of the wire guide head 1072c-05 to the coil groove shoulder 1072c-02. Proximate the outer portion of the wire guide head 1072c-05, the first and second wire guide outer wall 1072c-15, 1072c- 18 curve from a direction that is approximately perpendicular a plane formed by the outer portion of the wire guide head 1072c-05 to a direction that is substantially parallel to the coil groove shoulder 1072c-02. The arc shape of the first and second wire guide outer wall 1072c-15, 1072c-18 does not have a constant radius of curvature but has an increasing radius of curvature as the first and second wire guide outer wall 1072c-15, 1072c-18 extend from the outer portion of the wire guide head 1072c-05.

As can also be seen, the first and second wire guide outer wall 1072c- 15, 1072c- 18 have a significant length - the length being in a direction substantially perpendicular to a radius of the bobbin base 1072c-04. For example, the length of the first and second wire guide outer wall 1072c-15, 1072c-18 is several times greater than a width of the first and second wire guide ramp 1072c-16, 1072c-19. Accordingly, the first and second wire guide outer wall 1072c-15, 1072c-18 have a length that is several times greater than a width of any wire guided by the first and second wire guide groove 1072c-09, 1072C-12.

As can be appreciated from FIG. 10, the wire guide backing 1072c-l 1 does not extend from the bobbin base 1072c-04 as much as the first and second wire bend guide 1072c-10, 1072c-13. With more particularity, the wire guide backing 1072c-ll has a chamfer with, proximate the coil groove shoulder 272c-02, the same radial distance as the base chamfer surface 1072c-06. Additionally, proximate the coil groove shoulder 1072c-02, the first and second wire bend guide 1072c-10, 1072c-13 extend from the bobbin base 1072c-04 more than the wire guide backing 1072c-ll.

Accordingly, during winding, a coil wire extending longitudinally (e.g., substantially parallel with the coil bobbin centerline CLio?2c) between the first wire bend guide 1072c-10 and the second wire bend guide 1072c-13 can be captured by the first wire bend guide 1072c-10 or the second wire bend guide 1072c-13 when the coil wire is displaced circumferentially about the coil bobbin centerline CLIO72C. After coil wire is captured, a coil winding machine may press the coil wire into the first wire guide groove 1072c-09 or the second wire guide groove 1072c-12.

The foregoing describes bobbins 272c, 1072c that include the wire guide head 272c-05, 1072c-05 comprising two wire guide grooves 272c-09, 272c-12, 1072c-09, 1072c- 12. In addition, the wire guide head 272c-05, 1072c-05 is configured to catch a coil wire during winding. The following describes embodiments that include a wire guide head having a single wire guide groove and a wire guide head that does not catch a coil wire.

Alternative bobbin with a single wire winding groove

FIGS. 11 and 12 show an alternative bobbin 1172c for low stress coil wire winding. The alternative bobbin 1172c has a single wire guide groove, as is discussed in more detail in the following. As shown in FIGS. 11 and 12, bobbin 1172c has a hollow cylindrical shape that is substantially symmetric about a coil bobbin centerline CLn72c. The bobbin 1172c, or a wire winding tool, may be rotated about the coil bobbin centerline CLn72c so as to form a coil similar to the coil 276c described above.

The bobbin 1172c is shown in FIGS. 11 and 12 as including a coil groove lip 1172c-01 and a coil groove shoulder 1172c-02. Between the coil groove lip 1172c-01 and the coil groove shoulder 1172c-02 is a coil groove 1172c-03. The coil groove shoulder 1172c-02 is shown as being a feature of the bobbin base 1172c-04. As can be appreciated, similar to the bobbins 272c, 1072c described above, the coil groove lip 1172c-01, coil groove shoulder 1172c-02, and the coil groove 1172c-03 are substantially symmetric about the coil bobbin centerline CLn72c.

The bobbin base 1172c-04 also includes a wire guide head 1172c-05 that extends radially from the bobbin base 1172c-04. The wire guide head 1172c-05 may be used to wrap the coil wire about the bobbin 1172c in the coil groove 1172c-03. It can be appreciated from FIGS. 11 and 12 that the wire guide head 1172c-05 extends radially from a perimetric surface of a bobbin base 1172c-04. The bobbin base 1172c-04 is shown as having a cylindrical shape with a base chamfer surface 1172c-06. As can be seen, the base chamfer surface 1172c-06 extends from an outer portion of the bobbin base 1172c-04 to the coil groove shoulder 1172c-02 with a decreasing radial distance having a curvature. Accordingly, the base chamfer surface 1172c-06 forms a sloped or ramped surface extending towards the coil groove 1172c-03.

As shown in FIGS. 11 and 12, the wire guide head 1172c-05 is comprised of a first wire winding guide 1172c-07 and a second wire winding guide 1172c-08. The first wire winding guide 1172c-07 and the second wire winding guide 1172c-08 may respectively be an ingress wire winding guide and an egress wire winding guide, although any suitable arrangement and/or terms may be employed. The first and second wire winding guide 1172c-07, 1172c-08 can capture and restrain in the circumferential direction the coil wire during a winding of the coil wire about the bobbin 1172c.

In FIGS. 11 and 12, the first and second wire winding guide 1172c-07, 1172c-08 are shown as respectively being comprised of a wire guide groove 1172c-09 and a first wire bend guide 1172c- 10 and a second wire bend guide 1172c- 13. In contrast to the bobbins 272c, 1072c described above, a wire guide backing is not disposed between the first wire bend guide 1172c-10 and the second wire bend guide 1172c-13. Accordingly, a single wire guide groove 1172c-09 is employed. The wire guide groove 1172c-09 is between and is at least partially defined by the first wire bend guide 1172c- 10 and the second wire bend guide 1172c- 13.

As shown in FIGS. 11 and 12, the wire guide groove 1172c-09 is comprised of a a first wire guide outer wall 1172c-15, a wire guide ramp 1172c-16, and a second wire guide outer wall 1172c- 18. As can be appreciated, the wire guide ramp 1172c- 16 and the first and second wire guide outer wall 1172c-15, 1172c- 18 are comprised of curvilinear surfaces.

For example, the first and second wire guide outer wall 1172c-15, 1172c-18 are comprised of symmetrical arcs that curve from an outer portion of the wire guide head 1172c-05 to the coil groove shoulder 1172c-02. Proximate the outer portion of the wire guide head 1172c-05, the first and second wire guide outer wall 1172c-15, 1172c- 18 curve from a direction that is approximately perpendicular a plane formed by the outer portion of the wire guide head 1172c-05 to a direction that is substantially parallel to the coil groove shoulder 1172c-02. The arc shape of the first and second wire guide outer wall 1172c-15, 1172c-18 does not have a constant radius of curvature but has an increasing radius of curvature as the first and second wire guide outer wall 1172c-15, 1172c-l 8 extend from the outer portion of the wire guide head 1172c-05.

As can also be seen, the first and second wire guide outer wall 1172c- 15, 1172c- 18 have a significant length - the length being in a direction perpendicular to a radius of the bobbin base 1172c-04. However, the length of the first and second wire guide outer wall 1172c-15, 1172c-18 is not several times greater than a width of the wire guide ramp 1172c-16, 1172c-19, in contrast to the coil bobbins 272c, 1072c described above. Regardless, the length of the first and second wire guide outer wall 1172c-15, 1172c-18 are several more times greater than a width of any coil wire guided by the wire guide groove 1172c-09, 1172c-12.

During winding, a coil wire extending longitudinally (e.g., substantially parallel with the coil bobbin centerline CLn72c) between the first wire bend guide 1172c-10 and the second wire bend guide 1172c- 13 can be captured by the first wire bend guide 1172c-10 or the second wire bend guide 1172c-13 when the coil wire is displaced circumferentially about the coil bobbin centerline CLn72c. After coil wire is captured, a coil winding machine may press the coil wire into the wire guide groove 1172c-09.

Wire guide head that does not catch a coil wire

FIGS. 13 and 14 show an alternative bobbin 1372c for low stress coil wire winding. The alternative bobbin 1372c includes a wire guide head that does not catch a coil wire, as is discussed in more detail in the following. As shown in FIGS. 13 and 14, bobbin 1372c has a hollow cylindrical shape that is substantially symmetric about a coil bobbin centerline CL1372C The bobbin 1372c, or a wire winding tool, may be rotated about the coil bobbin centerline CL 1372c so as to form a coil similar to the coil 276c described above.

The bobbin 1372c is shown in FIGS. 13 and 14 as including a coil groove lip 1372c-01 and a coil groove shoulder 1372c-02. Between the coil groove lip 1372c-01 and the coil groove shoulder 1372c-02 is a coil groove 1372c-03. The coil groove shoulder 1372c-02 is shown as being a feature of the bobbin base 1372c-04. As can be appreciated, similar to the bobbins 272c, 1072c described above, the coil groove lip 1372c-01, coil groove shoulder 1372c-02, and the coil groove 1372c-03 are substantially symmetric about the coil bobbin centerline CL1372C.

The bobbin base 1372c-04 also includes a wire guide head 1372c-05 that extends radially from the bobbin base 1372c-04. The wire guide head 1372c-05 may be used to wrap the coil wire about the bobbin 1372c in the coil groove 1372c-03. It can be appreciated from FIGS. 13 and 14 that the wire guide head 1372c-05 extends radially from a perimetric surface of a bobbin base 1372c-04. The bobbin base 1372c-04 is shown as having a cylindrical shape with a base chamfer surface 1372c-06. As can be seen, the base chamfer surface 1372c-06 extends from an outer portion of the bobbin base 1372c-04 to the coil groove shoulder 1372c-02 with a decreasing radial distance. Accordingly, the base chamfer surface 1372c-06 forms a sloped or ramped surface extending towards the coil groove 1372c-03.

As shown in FIGS. 13 and 14, the wire guide head 1372c-05 is comprised of a first wire winding guide 1372c-07 and a second wire winding guide 1372c-08. The first wire winding guide 1372c-07 and the second wire winding guide 1372c-08 may respectively be an ingress wire winding guide and an egress wire winding guide, although any suitable arrangement and/or terms may be employed. The first and second wire winding guide 1372c-07, 1372c-08 can capture and restrain in the circumferential direction the coil wire during a winding of the coil wire about the bobbin 1372c.

In FIGS. 13 and 14, the first and second wire winding guide 1372c-07, 1372c-08 are shown as respectively being comprised of a first wire guide groove 1372c-09 and a first wire bend guide 1372c-10, and a second wire guide groove 1372c-12 and a second wire bend guide 1372c-13. A wire guide backing 1372c-ll is disposed between the first wire bend guide 1372c-10 and the second wire bend guide 1372c-13. The first wire guide groove 1372c-09 is between and is at least partially defined by the first wire bend guide 1372c-10 and the wire guide backing 1372c-ll. Similarly, the second wire guide groove 1372c-12 is between and is at least partially defined by the second wire bend guide 1372c- 13 and the wire guide backing 1372c-ll.

As shown in FIGS. 13 and 14, the first wire guide groove 1372c-09 is comprised of a first wire guide inner wall 1372c- 14, a first wire guide ramp 1372c- 16, and a first wire guide outer wall 1372c-15. Similarly, the second wire guide groove 1372c-12 is comprised of a second wire guide inner wall 1372c- 17, a second wire guide ramp 1372c-19, and a second wire guide outer wall 1372c-18. As can be appreciated, the first and second wire guide inner wall 1372c-14, 1372c-17, the first and second wire guide ramp 1372c-16, 1372c-19, and the first and second wire guide outer wall 1372c-15, 1372c-18 are comprised of curvilinear surfaces.

For example, the first and second wire guide outer wall 1372c-15, 1372c-18 are comprised of symmetrical arcs that curve from an outer portion of the wire guide head 1372c-05 to the coil groove shoulder 1372c-02. Proximate the outer portion of the wire guide head 1372c-05, the first and second wire guide outer wall 1372c-15, 1372c-18 curve from a direction that is approximately perpendicular a plane formed by the outer portion of the wire guide head 1372c-05 to a direction that is substantially parallel to the coil groove shoulder 1372c-02. The arc shape of the first and second wire guide outer wall 1372c-15, 1372c-18 does not have a constant radius of curvature but has an increasing radius of curvature as the first and second wire guide outer wall 1372c-15, 1372c-18 extend from the outer portion of the wire guide head 1372c-05.

As can also be seen, the first and second wire guide outer wall 1372c- 15, 1372c- 18 have a significant length. For example, the length of the first and second wire guide outer wall 1372c- 15, 1372c- 18 is several times greater than a width of the first and second wire guide ramp 1372c-16, 1372c-19. Accordingly, the first and second wire guide outer wall 1372c-15, 1372c-18 have a length several times greater than a width of a coil wire guided by the first and second wire guide groove 1372c-09, 1372c-12.

As can be appreciated from FIGS. 13 and 14, the wire guide backing 1372c- 11 extends from the bobbin base 1372c-04 as much as the first and second wire bend guide 1372c-10, 1372c-13. With more particularity, the wire guide backing 1372c-ll does not have a chamfer with, proximate the coil groove shoulder 1372c-02, the same radial distance as the base chamfer surface 1372c-06. Additionally, proximate the coil groove shoulder 1372c-02, the first and second wire bend guide 1372c-10, 1372c-13 includes chamfers that extend from the bobbin base 1372c-04 the same distance as the chamfer of the wire guide backing 1372c-ll.

Accordingly, during winding, a coil wire extending longitudinally (e.g., substantially parallel with the coil bobbin centerline CLi372c) between the first wire bend guide 1372c-10 and the second wire bend guide 1372c-13 may not necessarily, but could, be captured by the first wire bend guide 1372c- 10 or the second wire bend guide 1372c-13 when the coil wire is displaced circumferentially about the coil bobbin centerline CL1372C. Instead, a coil winding machine may press the coil wire into the first wire guide groove 1372c-09 or the second wire guide groove 1372c-12 prior to winding. Features of a bobbin for low stress coil wire winding

From the foregoing description, a bobbin 272c, 1072c, 1172c, 1372c for a low stress coil wire winding may comprise a coil groove 272c-03, 1072c-03, 1172c-03, 1372c-03 extending between a proximate end and a distal end of the bobbin 272c, 1072c, 1172c, 1372c. The proximate end may be proximate where a coil winding machine ingresses and egresses a coil wire respectively to and from the bobbin 272c, 1072c, 1172c, 1372c. The distal end of the bobbin 272c, 1072c, 1172c, 1372c may be distal from where the coil winding machine ingresses and egresses the coil wire respectively to and from the bobbin.

The bobbin 272c, 1072c, 1172c, 1372c may also include a wire guide head 272c- 05, 1072c-05, 1172c-05, 1372c-05 at the proximate end. The wire guide head 272c-05, 1072c-05, 1172c-05, 1372c-05 may comprise one or more wire guide grooves 272c-09, 272c-12, 1072c-09, 1072c-12, 1172c-09, 1372c-09, 1372c- 12 extending through the wire guide head 272c-05, 1072c-05, 1172c-05, 1372c-05 to the coil groove 272c-03, 1072c-03, 1172c-03, 1372c-03. The one or more wire guide grooves 272c-09, 272c-12, 1072c-09, 1072c-12, 1172c-09, 1372c-09, 1372c-12 are curvilinear. Because the one or more wire guide grooves 272c-09, 272c-12, 1072c-09, 1072c-12, 1172c-09, 1372c-09, 1372c-12 are curvilinear, a coil wire disposed in the wire guide grooves 272c-09, 272c- 12, 1072c-09, 1072c-12, 1172c-09, 1372c-09, 1372c-12 will not be subjected to significant stress. For example, the coil wire will not have a 90-degree bend that is under tension during or after coil wire winding. The one or more wire guide grooves 272c-09, 272c-12, 1072c-09, 1072c-12, 1172c-09, 1372c-09, 1372c-12 being curvilinear may comprise the one or more wire guide grooves 272c-09, 272c-12, 1072c-09, 1072c-12, 1172c-09, 1372c-09, 1372c-12 extending from the outer end of the wire guide head 272c-05, 1072c-05, 1172c-05, 1372c-05 to the coil groove 272c-03, 1072c-03, 1172c-03, 1372c-03 in a substantially continuous curve. That is, the one or more wire guide grooves 272c-09, 272c-12, 1072c- 09, 1172c-09, 1372c-09, 1372c-12 do not include, for example, 90-degree corners. The curve of the one or more wire guide grooves 272c-09, 272c-12, 1072c-09, 1172c-09, 1372c-09, 1372c-12 may be in the radial direction (e.g., orthogonal to the coil bobbin centerline CL272C, CLIO72C, CLn72c, CLi372c) and/or the perimetrical direction (e.g., circumferential about the coil bobbin centerline CL272C, CLIO72C, CLii72c, CLi372c). Additionally, the one or more wire guide grooves 272c-09, 272c-12, 1072c-09, 1072c- 12, 1172c-09, 1372c-09, 1372c-12 being curvilinear may comprise the ends of the one or more wire guide grooves 272c-09, 272c-12, 1072c-09, 1072c-12, 1172c-09, 1372c- 09, 1372c-12 being substantially parallel with, for example, a surface at an outer portion of the bobbin base 272c-04, 1072c-04, 1172c-04, 1372c-04 and the coil groove 272c-03, 1072c-03, 1172C-03, 1372c-03.

The coil groove 272c-03, 1072c-03, 1172c-03, 1372c-03 extending between the proximate end and the distal end may comprise the coil groove 272c-03, 1072c-03, 1172c-03, 1372c-03 extending between a coil groove lip 272c-01, 1072c-01, 1172c-01, 1372c-01 at the distal end of the bobbin 272c, 1072c, 1172c, 1372c and a coil groove shoulder 272c-02, 1072c-02, 1172c-02, 1372c-02 at the proximate end of the bobbin 272c, 1072c, 1172c, 1372c. For example, a radial distance of the coil groove lip 272c- 01, 1072c-01, 1172c-01, 1372c-01 at the distal end of the bobbin 272c, 1072c, 1172c, 1372c and a radial distance of the coil groove shoulder 272c-02, 1072c-02, 1172c-02, 1372c-02 at the proximate end of the bobbin 272c, 1072c, 1172c, 1372c may be substantially equal. Additionally, or alternatively, a radial distance of the wire guide head 272c-05, 1072c-05, 1172c-05, 1372c-05 may be greater than the radial distance of the coil groove shoulder 272c-02, 1072c-02, 1172c-02, 1372c-02. The wire guide head 272c-05, 1072c-05, 1172c-05, 1372c-05 may also comprise a wire guide head chamfer extending from a radial distance of the wire guide head 272c-05, 1072c-05, 1172c-05, 1372c-05 to a radial distance of the coil groove shoulder 272c-02, 1072c-02, 1172c-02, 1372c-02.

The one or more wire guide grooves 272c-09, 272c-12, 1072c-09, 1072c-12, 1172c-09, 1372c-09, 1372c-12 extending through the wire guide head 272c-05, 1072c- 05, 1172c-05, 1372c-05 to the coil groove 272c-03, 1072c-03, 1172c-03, 1372c-03 may comprise the one or more wire guide grooves 272c-09, 272c-12, 1072c-09, 1072c-12, 1172c-09, 1372c-09, 1372c-12 radially sloping from a radial distance of the wire guide head 272c-05, 1072c-05, 1172c-05, 1372c-05 to a radial distance of the coil groove 272c-03, 1072c-03, 1172c-03, 1372c-03. Additionally, or alternatively, the one or more wire guide grooves 272c-09, 272c-12, 1072c-09, 1072c-12, 1172c-09, 1372c-09, 1372c- 12 extending through the wire guide head 272c-05, 1072c-05, 1172c-05, 1372c-05 to the coil groove 272c-03, 1072c-03, 1172c-03 may comprise the one or more wire guide grooves 272c-09, 272c-12, 1072c-09, 1072c-12, 1172c-09, 1372c-09, 1372c-12 perimetrically curving from the proximate end of the bobbin 272c, 1072c, 1172c, 1372c to the coil groove 272c-03, 1072c-03, 1172c-03, 1372c-03.

The one or more wire guide grooves 272c-09, 272c-12, 1072c-09, 1072c-12, 1172c-09, 1372c-09, 1372c-12 may comprise a wire guide ramp 272c-16, 272c-19, 1072c-16, 1072c-19, 1172c-16, 1372c-16, 1372c-19. The radial distance of the wire guide head 272c-05, 1072c-05, 1172c-05, 1372c-05 comprises a radial distance of the wire guide ramp 272c-16, 272c-19, 1072c-16, 1072c-19, 1172c-16, 1372c-16, 1372c-19. The one or more wire guide grooves 272c-09, 272c-12, 1072c-09, 1072c-12, 1172c-09, 1372c-09, 1372c-12 may comprise a wire guide inner wall 272c-14, 272c-17, 1072c-14, 1072c-17, 1372c-14, 1372c-17 and/or a wire guide outer wall 272c-15, 272c-18, 1072c- 15, 1072c-18, 1172c-15, 1172c-18, 1372c-15, 1372c-18. The wire guide outer wall 272c-15, 272c-18, 1072c-15, 1072c-18, 1172c-15, 1172c-18, 1372c-15, 1372c-18 is configured to retain and bend the coil wire. As can be appreciated, alternative one or more wire guide grooves may be comprised of a single wire guide groove. For example, an alternative bobbin may not include a wire guide backing. Accordingly, the single wire guide groove may extend between a first and second wire guide wall and may not include inner guide walls.

The wire guide head 272c-05, 1072c-05, 1172c-05, 1372c-05 may comprise a first wire bend guide 272c-10, 1072c-10, 1172c-10, 1372c-10 and a second wire bend guide 272c-13, 1072c-13, 1172c-13, 1372c-13. The first wire bend guide 272c-10, 1072c-10, 1172c-10, 1372c-10 and the second wire bend guide 272c-13, 1072c-13, 1172c-13, 1372c-13 respectively comprising one of the one or more wire guide grooves 272c-09, 272c-12, 1072c-09, 1072c-12, 1172c-09, 1372c-09, 1372c-12. The first wire bend guide 272c-10, 1072c-10, 1172c-10, 1372c-10 and the second wire bend guide 272c-13, 1072c-13, 1172c-13, 1372c-13 may have a radial distance that is greater than a radial distance of a wire guide backing 272c-ll, 1072c-ll. 1372c-ll disposed between the first wire bend guide 272c-10, 1072c-10, 1172c-10, 1372c-10 and the second wire bend guide 272c-13, 1072c-13, 1172c-13, 1372c-13.

As can be appreciated, the benefits of the bobbin 272c, 1072c, 1172c, 1372c may be realized when the coil wire is wound about the bobbin 272c, 1072c, 1172c, 1372c. The following describes exemplary methods of such coil wire winding.

Methods of coil wire winding

FIG. 15 shows a method 1500 of forming a bobbin for low stress coil wire winding. As shown in FIG. 15, the method 1500, in step 1510 forms a coil groove extending between a proximate end and a distal end of the bobbin. The bobbin may be the bobbins 272c, 1072c, 1172c, 1372c described above although any suitable bobbin may be employed. When the coil groove is formed, the bobbin may only be partially formed, but may nevertheless be referred to as a bobbin. In step 1520, the method 1500 forms a wire guide head at the proximate end, wherein forming the wire guide head comprises forming one or more wire guide grooves extending through the wire guide head to the coil groove. The one or more wire guide grooves may be curvilinear. That is, for example, the one or more grooves may radially slope from a radial distance of an outside portion of the wire guide head to a radial distance of the coil groove.

In the step 1510, forming the coil groove extending between the proximate end and the distal end may comprise forming the coil groove extending between a coil groove lip at the distal end of the bobbin and a coil groove shoulder at the proximate end of the bobbin. A radial distance of the coil groove lip at the distal end of the bobbin and a radial distance of the coil groove shoulder at the proximate end of the bobbin may be substantially equal. Additionally, or alternatively, the radial distance of the wire guide head may be greater than the radial distance of the coil groove shoulder. The wire guide head may comprise a wire guide head chamfer extending from the radial distance of the wire guide head to the radial distance of the coil groove shoulder. The wire guide head chamfer may ensure that the coil wire is not subjected to lateral stress or deformation, abrasion, dislocation or displacement, or the like, by the wire guide head while the coil wire is being wound about the bobbin into the coil groove. Accordingly, the coil wire is not undesirably deformed, severed, fatigued, or the like.

In the step 1520, forming the one or more wire guide grooves extending through the wire guide head to the coil groove may comprise forming the one or more wire guide grooves to radially slope from a radial distance of the wire guide head to a radial distance of the coil groove. Additionally, or alternatively, forming the one or more wire guide grooves extending through the wire guide head to the coil groove may comprise forming the one or more wire guide grooves to perimetrically curve from the proximate end of the bobbin to the coil groove. Additionally, or alternatively, in the step 1520, forming the one or more wire guide grooves may comprise forming a wire guide ramp, wherein the radial distance of the wire guide head comprises a radial distance of the wire guide ramp. Additionally, or alternatively, forming the one or more wire guide grooves may comprise forming a wire guide inner wall and/or a wire guide outer wall, the wire guide outer wall being configured to retain and bend the coil wire. For example, the wire guide outer wall may perimetrically curve from the outer portion of the wire guide head to the coil groove shoulder.

Forming the wire guide head may comprise forming a first wire bend guide and a second wire bend guide, where the first wire bend guide and the second wire bend guide may respectively comprise one of the one or more wire guide grooves. Additionally, or alternatively, the first wire bend guide and the second wire bend guide may have a radial distance that is greater than a radial distance of a wire guide backing disposed between the first wire bend guide and the second wire bend guide.

As can be appreciated, a bobbin, such as the bobbins 272c, 1072c, 1172c, 1372c described above, is used during an assembly of the coil assembly 270c. For example, the bobbin may provide for low stress coil wire winding. An exemplary method of such an assembly is described below, with reference to FIG. 16. FIG. 16 shows a method 1600 of forming a coil transducer including a bobbin for low stress coil wire winding. The method 1600 may provide the bobbin according to the method 1500 described with reference to FIG. 15 in step 1610. In step 1620, the method 1600 disposes a coil wire in one of the one or more wire guide grooves of the bobbin. The method 1600, in step 1630, winds the coil wire about the bobbin and into the coil groove. Accordingly, a coil, such as the coil 276c described above, may be formed. Because the bobbin is provided by the method 1500 and therefore includes wire guide grooves that are curvilinear, the coil wire disposed in the one of the one or more wire guide grooves according to the method 1600 may be curvilinear. A curvilinear coil wire may be defined as a coil wire having only a curve or curves having radii that are greater than or significantly greater than a radius of the coil wire. Accordingly, a curvilinear coil wire may also be defined by a coil wire with no bends having a radius about or less than a radius of the coil wire. The method 1600 may further comprise disposing the coil wire in another one of the one or more wire guide grooves, wherein the coil wire in the another one of the one or more wire guide grooves is curvilinear.

The bobbin 272c, 1072c, 1172c, 1372c and methods 1500, 1600 described above can be used for low stress coil wire winding. For example, the bobbin 272c, 1072c, 1172c, 1372c includes one or more wire guide grooves that are curvilinear. As a result, a corner or other sharp feature may not place a lateral force on the coil wire thereby avoiding a bending moment or flexing of the coil wire. This can reduce the localized stress in the coil wire which can ensure that the coil wire does not fail during winding. In addition, due to the relatively low stress and resulting lack of strain of the coil wire, the mechanical and electrical properties of the coil wire may remain the same after the winding of the coil wire. For example, the cross-sectional area of the coil wire may be the same after the coil wire is wound about the bobbin. Therefore, electrical properties, such as electrical resistance may remain the same. Additionally, or alternatively, the mechanical properties may also remain the same thereby allowing for consistent, for example, thermal properties, such as a consistent thermal expansion of the coil wire. This can ensure that the electrical properties may remain predictable after the coil wire is wound.

The detailed descriptions of the above embodiments are not exhaustive descriptions of all embodiments contemplated by the inventors to be within the scope of the present description. Indeed, persons skilled in the art will recognize that certain elements of the above-described embodiments may variously be combined or eliminated to create further embodiments, and such further embodiments fall within the scope and teachings of the present description. It will also be apparent to those of ordinary skill in the art that the above-described embodiments may be combined in whole or in part to create additional embodiments within the scope and teachings of the present description.

Thus, although specific embodiments are described herein for illustrative purposes, various equivalent modifications are possible within the scope of the present description, as those skilled in the relevant art will recognize. The teachings provided herein can be applied to other bobbins for low stress coil wire winding. Accordingly, the scope of the embodiments described above should be determined from the following claims.

Claims

We claim:

1. A bobbin (272c, 1072c, 1172c, 1372c) for a low stress coil wire winding, the bobbin (272c, 1072c, 1172c, 1372c) comprising: a coil groove (272c-03, 1072c-03, 1172c-03, 1372c-03) extending between a proximate end and a distal end of the bobbin (272c, 1072c, 1172c, 1372c); and a wire guide head (272c-05, 1072c-05, 1172c-05, 1372c-05) at the proximate end, the wire guide head (272c-05, 1072c-05, 1172c-05, 1372c-05) comprising one or more wire guide grooves (272c-09, 272c-12, 1072c-09, 1072c-12, 1172c-09, 1372c-09, 1372c-12) extending through the wire guide head (272c-05, 1072c-05, 1172c-05, 1372c-05) to the coil groove (272c-03, 1072c-03, 1172c-03, 1372c-03); wherein the one or more wire guide grooves (272c-09, 272c-12, 1072c-09, 1072c-12, 1172c-09, 1372c-09, 1372c-12) are curvilinear.

2. The bobbin (272c, 1072c, 1172c, 1372c) of claim 1, wherein the coil groove (272c-03, 1072c-03, 1172c-03, 1372c-03) extending between the proximate end and the distal end comprises the coil groove (272c-03, 1072c-03, 1172c-03, 1372c-03) extending between a coil groove lip (272c-01, 1072c-01, 1172c-01, 1372c-01) at the distal end of the bobbin (272c, 1072c, 1172c, 1372c) and a coil groove shoulder (272c- 02, 1072c-02, 1172c-02, 1372c-02) at the proximate end of the bobbin (272c, 1072c, 1172c, 1372c).

3. The bobbin (272c, 1072c, 1172c, 1372c) of claim 2, wherein a radial distance of the coil groove lip (272c-01, 1072c-01, 1172c-01, 1372c-01) at the distal end of the bobbin (272c, 1072c) and a radial distance of the coil groove shoulder (272c-02, 1072c- 02, 1172c-02, 1372c-02) at the proximate end of the bobbin (272c, 1072c, 1172c, 1372c) are substantially equal.

4. The bobbin (272c, 1072c, 1172c, 1372c) of claim 3, wherein a radial distance of the wire guide head (272c-05, 1072c-05, 1172c-05, 1372c-05) is greater than the radial distance of the coil groove shoulder (272c-02, 1072c-02, 1172c-02, 1372c-02).

5. The bobbin (272c, 1072c, 1172c, 1372c) of claim 4, wherein the wire guide head (272c-05, 1072c-05, 1172c-05, 1372c-05) comprises a wire guide head chamfer extending from the radial distance of the wire guide head (272c-05, 1072c-05, 1172c-05, 1372c-05) to the radial distance of the coil groove shoulder (272c-02, 1072c-02, 1172c- 02, 1372c-02).

6. The bobbin (272c, 1072c, 1172c, 1372c) of one of the foregoing claims 1 through 5, wherein the one or more wire guide grooves (272c-09, 272c-12, 1072c-09, 1072c-12, 1172c-09, 1372c-09, 1372c-12) extending through the wire guide head (272c- 05, 1072c-05, 1172c-05, 1372c-05) to the coil groove (272c-03, 1072c-03, 1172c-03, 1372c-03) comprises at least one of: the one or more wire guide grooves (272c-09, 272c-12, 1072c-09, 1072c-12, 1172c-09, 1372c-09, 1372c-12) radially sloping from a radial distance of the wire guide head (272c-05, 1072c-05, 1172c-05, 1372c-05) to a radial distance of the coil groove (272c-03, 1072c-03, 1172c-03, 1372c-03); and the one or more wire guide grooves (272c-09, 272c-12, 1072c-09, 1072c-12, 1172c-09, 1372c-09, 1372c-12) perimetrically curving from the proximate end of the bobbin (272c, 1072c, 1172c, 1372c) to the coil groove (272c-03, 1072c-03, 1172c-03, 1372c-03).

7. The bobbin (272c, 1072c, 1172c, 1372c) of claim 6, wherein the one or more wire guide grooves (272c-09, 272c-12, 1072c-09, 1072c-12, 1172c-09, 1372c-09, 1372c-12) comprises a wire guide ramp (272c-16, 272c-19, 1072c-16, 1072c-19, 1172c- 16, 1372c-16, 1372c-19), wherein the radial distance of the wire guide head (272c-05, 1072c-05, 1172c-05, 1372c-05) comprises a radial distance of the wire guide ramp (272C-16, 272c-19, 1072c-16, 1072c-19, 1172c-16, 1372c-16, 1372c-19).

8. The bobbin (272c, 1072c, 1172c, 1372c) of claim 6, wherein the one or more wire guide grooves (272c-09, 272c-12, 1072c-09, 1072c-12, 1172c-09, 1372c-09, 1372c-12) comprise at least one of a wire guide inner wall (272c-14, 272c-17, 1072c-14, 1072c-17, 1372c-14, 1372c-17) and a wire guide outer wall (272c-15, 272c-18, 1072c- 15, 1072c-18), the wire guide outer wall (272c-15, 272c-18, 1072c-15, 1072c-18, 1172c-15, 1172c-18, 1372c-15, 1372c-18) being configured to retain and bend the coil wire.

9. The bobbin (272c, 1072c, 1172c, 1372c) of one of the foregoing claims 1 through 8, wherein the wire guide head (272c-05, 1072c-05, 1172c-05, 1372c-05) comprises a first wire bend guide (272c-10, 1072c-10, 1172c-10, 1372c-10) and a second wire bend guide (272c-13, 1072c-13, 1172c-13, 1372c-13), the first wire bend guide (272c-10, 1072c-10, 1172c-10, 1372c-10) and the second wire bend guide (272c- 13, 1072c-13, 1172c-13, 1372c-13) respectively comprising one of the one or more wire guide grooves (272c-09, 272c-12, 1072c-09, 1072c-12, 1172c-09, 1372c-09, 1372c-12).

10. The bobbin (272c, 1072c, 1172c, 1372c) of claim 9, wherein the first wire bend guide (272c-10, 1072c-10, 1172c-10, 1372c-10) and the second wire bend guide (272c- 13, 1072c-13, 1172c-13, 1372c-13) have a radial distance that is greater than a radial distance of a wire guide backing (272c-l l, 1072c-l l, 1172c-ll, 1372c-ll) disposed between the first wire bend guide (272c-10, 1072c-10, 1172c-10, 1372c-10) and the second wire bend guide (272c-13, 1072c-13, 1172c-13, 1372c-13).

11. A coil transducer (270) having a bobbin for low stress coil wire winding, the coil transducer (270) comprising: a magnet assembly (270m); and a coil assembly (270c), the coil assembly (270c) comprising: a coil (276c); and a bobbin (272c, 1072c, 1172c, 1372c) according to one of the foregoing claims 1 through 10, the bobbin (272c, 1072c, 1172c, 1372c) being disposed within the coil (276c).

12. A sensor assembly (10) having a bobbin for a low stress coil wire winding, the sensor assembly (10) comprising: a conduit (130); an opposing body; and a coil transducer (270) according to the foregoing claim 11 mechanically coupled to the conduit (130) and the opposing body.

13. The sensor assembly (10) of claim 12, wherein the opposing body comprises one of a conduit (130’), a reference body, and a balance bar.

14. A method of forming a bobbin for a low stress coil wire winding, the method comprising: forming a coil groove extending between a proximate end and a distal end of the bobbin; and forming a wire guide head at the proximate end, wherein forming the wire guide head comprises forming one or more wire guide grooves extending through the wire guide head to the coil groove; wherein the one or more wire guide grooves are curvilinear.

15. The method of claim 14, wherein forming the coil groove extending between the proximate end and the distal end comprises forming the coil groove extending between a coil groove lip at the distal end of the bobbin and a coil groove shoulder at the proximate end of the bobbin.

16. The method of claim 15, wherein a radial distance of the coil groove lip at the distal end of the bobbin and a radial distance of the coil groove shoulder at the proximate end of the bobbin are substantially equal.

17. The method of claim 16, wherein a radial distance of the wire guide head is greater than the radial distance of the coil groove shoulder.

18. The method of claim 17, wherein the wire guide head comprises a wire guide head chamfer extending from the radial distance of the wire guide head to the radial distance of the coil groove shoulder.

19. The method of one of the foregoing claims 14 through 18, wherein forming the one or more wire guide grooves extending through the wire guide head to the coil groove comprises at least one of: forming the one or more wire guide grooves to radially slope from the radial distance of the wire guide head to a radial distance of the coil groove; and forming the one or more wire guide grooves to perimetrically curve from the proximate end of the bobbin to the coil groove.

20. The method of claim 19, wherein forming the one or more wire guide grooves comprises forming a wire guide ramp, wherein the radial distance of the wire guide head comprises a radial distance of the wire guide ramp.

21. The method of claim 20, wherein forming the one or more wire guide grooves comprises forming at least one of a wire guide inner wall and a wire guide outer wall, the wire guide outer wall being configured to retain and bend the coil wire.

22. The method of one of the foregoing claims 14 through 21, wherein forming the wire guide head comprises forming a first wire bend guide and a second wire bend guide, the first wire bend guide and the second wire bend guide respectively comprising one of the one or more wire guide grooves.

23. The method of claim 22, wherein the first wire bend guide and the second wire bend guide have a radial distance that is greater than a radial distance of a wire guide backing disposed between the first wire bend guide and the second wire bend guide.

24. A method of forming a coil transducer, the method comprising: providing a bobbin according to one of the foregoing claims 14 through 22; and disposing a coil wire in one of the one or more wire guide grooves; and winding the coil wire about the bobbin and into the coil groove; wherein the coil wire in the one of the one or more wire guide grooves is curvilinear.

25. The method of claim 24, further comprising disposing the coil wire in another one of the one or more wire guide grooves, wherein the coil wire in the another one of the one or more wire guide grooves is curvilinear.