Flat coil carrier

1 . A flat coil carrier for a flat coil, comprising:

a carrier body for receiving a spirally wound coil wire;

the carrier body including, on an axial front side, a groove spiral configured to receive the coil wire, the groove spiral having an axially open groove opening and extending spirally on the carrier body transversely to an axial direction such that the groove spiral includes a plurality of radially consecutive groove sections;

the plurality of radially consecutive groove sections each having an axially open groove section opening of a plurality of groove section openings;

wherein the plurality of radially consecutive groove sections are each separated from one another by a common separating wall section of a plurality of separating wall sections of the carrier body;

wherein at least one of the plurality of separating wall sections protrudes from the carrier body and has at least one undercut section including a radially protruding protrusion that radially reduces a corresponding groove section opening of the plurality of groove section openings such that an undercut for the coil wire is formed in the at least one undercut section;

wherein the carrier body further includes a plurality of axial apertures disposed in a bottom of the groove spiral, at least a subset of the plurality of axial apertures disposed in radial alignment with one another; and

wherein the protrusion and a corresponding axial aperture of the plurality of axial apertures are at least partially aligned with one another in the axial direction.

2 . The flat coil carrier according to claim 1 , wherein the at least one undercut section includes at least two undercut sections spaced apart from one another along the groove spiral via a plurality of separating sections of the groove spiral, which are free from undercuts.

3 . The flat coil carrier according to claim 1 , wherein:

the groove spiral has a plurality of radially extending undercut segments, in which the plurality of separating wall sections each have a respective protrusion projecting radially therefrom and forming a respective undercut; and

the groove spiral has a plurality of radially extending separating segments, which are free from undercuts and which separate consecutive undercut segments of the plurality of undercut segments from one another.

4 . The flat coil carrier according to claim 3 , wherein:

an extension of the respective protrusion along the groove spiral increases with increasing radial distance of the respective protrusion from a radial center of the groove spiral around which the groove spiral extends spirally;

the plurality of separating segments each include a plurality of radially consecutive separating sections; and

an extension along the groove spiral of each of the plurality of radially consecutive separating sections is identical.

5 . The flat coil according to claim 3 , wherein the subset of the plurality of axial apertures are disposed in radial alignment with one of the plurality of undercut segments.

6 . The flat coil carrier according to claim 1 , wherein, relative to a radial center of the groove spiral, the protrusion protrudes radially outward from the respective separating wall section.

7 . A method for producing a flat coil carrier according to claim 1 , comprising:

providing an injection molding tool including an upper tool part and a lower tool part, which define a hollow space in a closed state of the injection molding tool, the upper tool part and the lower tool part configured to cooperate with one another without being engaged behind such that the injection molding tool is openable via separating the upper tool part and the lower tool part from one another with a movement of the upper tool part and the lower tool part relative to one another in an axial direction;

closing the injection molding tool and injecting a plastic into the hollow space to produce the flat coil carrier; and

opening the injection molding tool and removing the produced flat coil carrier.

8 . The method according to claim 7 , wherein:

the upper tool part has a first shoulder, which, in the closed state, protrudes toward the lower tool part;

the lower tool part has a second shoulder, which, in the closed state, protrudes toward the upper tool part;

the first shoulder has a first flat side and the second shoulder has a second flat side, the first flat side and the second flat side radially facing and abutting one another in the closed state; and

the first shoulder is axially spaced apart from the lower tool part in the closed state such that the hollow space extends axially between the first shoulder and the lower tool part and extends radially to the second flat side of the second shoulder for producing a corresponding protrusion.

9 . An injection molding tool for producing a flat coil carrier according to the method of claim 8 .

10 . The flat coil carrier according to claim 1 , wherein a radial surface of the respective separating wall section, which faces toward or away from a radial center of the groove spiral, defines at least a portion of the undercut and at least a portion of a respective axial aperture of the plurality of axial apertures.

11 . A flat coil, comprising a flat coil carrier and a coil wire, the coil carrier including:

a carrier body including a groove spiral;

the groove spiral disposed on an axial front side of the carrier body and having an axially open groove opening;

the groove spiral extending spirally on the carrier body such that a spiral separating wall protruding axially from the carrier body extends parallel to the groove spiral and separates radially adjacent portions of the groove spiral;

wherein the carrier body further includes a plurality of protrusions projecting radially from the spiral separating wall into the groove spiral such that a plurality of undercuts configured to receive the coil wire are defined;

wherein, relative to a radial center of the groove spiral, the plurality of protrusions project radially outward from the spiral separating wall;

wherein the coil wire is received in the groove spiral;

wherein the plurality of protrusions are arranged along the spiral separating wall longitudinally spaced apart from one another such that the spiral separating wall includes a plurality of longitudinal undercut sections and a plurality of longitudinal separating sections disposed in an alternating manner;

wherein the carrier body further includes a plurality of undercut segments and a plurality separating segments extending radially from the radial center of the groove spiral and disposed about the radial center in an alternating manner;

wherein the plurality of undercut segments are each defined by a subset of the plurality of undercut sections that are disposed in radial alignment with one another;

wherein the plurality of separating segments are each defined by a subset of the plurality of separating sections that are disposed in radial alignment with one another;

wherein the plurality of undercut segments each extend over an angular area of 60° or less;

wherein the carrier body further includes a plurality of axial apertures disposed in a bottom of the groove spiral;

wherein, in at least one of the plurality of longitudinal undercut sections, a radial surface of the spiral separating wall, which faces toward or away from the radial center of the groove spiral, defines at least a portion of a respective undercut of the plurality of undercuts and at least a portion of a respective axial aperture of the plurality of axial apertures; and

wherein, in at least one of the plurality of longitudinal undercut sections, a respective protrusion of the plurality of protrusions and a respective axial aperture of the plurality of axial apertures are at least partially aligned with one another in the axial direction.

12 . The flat coil according to claim 11 , wherein:

the groove spiral has a rectangular basic layout having a plurality of consecutive longitudinal sides, which extend at least essentially tangentially; and

the plurality of consecutive longitudinal sides transition into one another via a plurality of curved corner sections of the groove spiral.

13 . The flat coil according to claim 12 , wherein at least one of the plurality of consecutive longitudinal sides has a curved curvature section with a radius of curvature, which is ten times to one hundred and fifty times a radius of curvature of an adjacent curved corner section of the plurality of curved corner sections.

14 . The flat coil according to claim 11 , wherein the flat coil carrier includes a clamp engaged with and fixing at least one longitudinal end of the coil wire to the flat coil carrier.

15 . A flat coil, comprising a coil wire and a flat coil carrier including a carrier body, wherein:

the carrier body includes:

a groove spiral extending spirally around an axis extending in an axial direction, the groove spiral disposed on an axial front side of the carrier body and having an axially open groove opening;

a spiral separating wall protruding axially from the carrier body, extending parallel to the groove spiral, and separating radially adjacent portions of the groove spiral;

at least one protrusion projecting radially from the spiral separating wall into the groove spiral such that an undercut configured to receive the coil wire is defined; and

at least one axial aperture disposed in a bottom of the groove spiral, the at least one protrusion and the at least one axial aperture at least partially aligned with one another in the axial direction;

the coil wire is received in the groove spiral;

the coil wire has a diameter that is i) larger than a radial dimension of the at least one protrusion and ii) smaller than a radial dimension of a radially reduced portion of the groove opening defined between the at least one protrusion and the spiral separating wall; and

a curved surface is arranged at a transition between the at least one protrusion and the spiral separating wall, the curved surface defining a corner region of the undercut and having a curvature corresponding to an outer contour of the coil wire.

16 . The flat coil according to claim 15 , wherein the at least one protrusion includes a plurality of protrusions arranged along the spiral separating wall longitudinally spaced apart from one another such that the spiral separating wall includes a plurality of longitudinal undercut sections and a plurality of longitudinal separating sections disposed in an alternating manner.

17 . The flat coil according to claim 16 , wherein:

the carrier body includes a plurality of undercut segments and a plurality separating segments extending radially from a radial center of the groove spiral and disposed about the radial center in an alternating manner;

the plurality of undercut segments are each defined by a subset of the plurality of undercut sections that are disposed in radial alignment with one another; and

the plurality of separating segments are each defined by a subset of the plurality of separating sections that are disposed in radial alignment with one another.

18 . The flat coil according to claim 16 , wherein:

the plurality of protrusions extend along the groove spiral a respective longitudinal distance and are disposed a respective radial distance from a radial center of the groove spiral; and

the respective radial distance and the respective longitudinal distance are positively correlated.

19 . The flat coil according to claim 16 , wherein:

the at least one axial aperture includes a plurality of axial apertures; and

in at least one of the plurality of longitudinal undercut sections, a radial surface of the spiral separating wall, which faces toward or away from a radial center of the groove spiral, defines at least a portion of the undercut and at least a portion of a respective axial aperture of the plurality of axial apertures.