Abstract
An electromagnetic switch for a starting device of an internal combustion engine may include a coil carrier, a coil winding, and a piston. The coil carrier may have a carrier wall which encloses a cavity. The coil winding may have a coil wire wound on a side of the carrier wall facing away from the cavity which provides a magnetic field within the cavity. The piston may be axially adjustable in the cavity. The piston may be disposed in a passive position and may be adjusted axially in a direction of a core. In the passive position, the piston and the core may define an axial gap therebetween in the cavity. The coil wire may have a first winding section and a second winding section wound in opposing directions. At least one winding of the second winding section may axially overlap the axial gap.
Claims
1. An electromagnetic switch for a starting device of an internal combustion engine, comprising: a coil carrier having a carrier wall which extends in an axial direction and which encloses a cavity in the coil carrier; a coil winding having a coil wire wound on a side of the carrier wall facing away from the cavity and which, during operation, is flowed through by an electrical current and provides a magnetic field within the cavity; a piston which is axially adjustable in the cavity and, when the coil winding is not in operation, is disposed in a passive position and, during operation of the coil winding, is adjusted axially in a direction of a core; in the passive position of the piston, the piston and the core defining an axial gap therebetween in the cavity; the coil wire, in an axially extending first winding section, wound in a first winding direction around the carrier wall; the coil wire, in an axially extending second winding section, wound in a second winding direction opposite the first winding direction around the carrier wall; and wherein at least one winding of the second winding section axially overlaps the axial gap.
2. The electromagnetic switch according to claim 1, wherein all windings of the second winding section axially overlap the axial gap.
3. The electromagnetic switch according to claim 1, wherein the second winding section axially adjoins the first winding section.
4. The electromagnetic switch according to claim 1, wherein: the coil wire has a third axial winding section wound in the first winding direction around the carrier wall; and the second winding section is arranged completely between the first winding section and the third winding section relative to the axial direction.
5. The electromagnetic switch according to claim 4, wherein at least one of: a side of the first winding section facing axially away from the second winding section is free from windings of the coil wire; and a side of the third winding section facing axially away from the second winding section is free from windings of the coil wire.
6. The electromagnetic switch according to claim 1, wherein: the coil wire has a third axial winding section wound in the first winding direction around the carrier wall; the carrier wall has a radial step such that, in a first wall section, the carrier wall has an outer diameter which is smaller than an outer diameter in a second wall section of the carrier wall that axially follows the first wall section, and the carrier wall has a chamber in the first wall section; and the coil wire is wound around the first wall section and around the second wall section such that: the first winding section radially contacts the first wall section; the second winding section radially contacts the second wall section proximal the radial step; and the third winding section radially contacts the second wall section on a side of the second winding section opposite the first winding section.
7. The electromagnetic switch according to claim 6, wherein a portion of the coil wire wound in the first winding direction fills the chamber.
8. The electromagnetic switch according to claim 6, wherein: the coil wire has a non-ferromagnetic first wire section and a ferromagnetic second wire section; and the first wall section is disposed spaced apart axially from the core, and the second wire section is wound onto the first wall section.
9. The electromagnetic switch according to claim 1, wherein a pitch of the coil wire in the second winding section varies.
10. The electromagnetic switch according to claim 9, wherein the pitch decreases axially toward the core.
11. The electromagnetic switch according to claim 1, wherein: the coil wire is wound in at least two radially successive rows around the carrier wall; and the second winding section is arranged in a row of the at least two rows that radially adjoins the carrier wall.
12. The electromagnetic switch according to claim 1, wherein the coil wire has a non-ferromagnetic first wire section and a ferromagnetic second wire section.
13. The electromagnetic switch according to claim 12, wherein the at least one winding of the second winding section that axially overlaps the axial gap is formed by the second wire section.
14. The electromagnetic switch according to claim 12, wherein the second winding section is formed by the second wire section.
15. The electromagnetic switch according to claim 12, wherein the second winding section is formed partially by the first wire section and partially by the second wire section.
16. The electromagnetic switch according to claim 12, wherein the second wire section is disposed spaced apart axially from the core.
17. The electromagnetic switch according to claim 1, further comprising a ferromagnetic bypass body surrounding the cavity and arranged radially between the cavity and the coil winding wherein: in the passive position of the piston, the bypass body axially overlaps the axial gap; and at least one winding of the second winding section axially overlaps the bypass body.
18. The electromagnetic switch according to claim 17, wherein the bypass body axially overlaps the axial gap entirely.
19. A starting device for starting an internal combustion engine, comprising: a starting element which, for starting of the internal combustion engine, engages with a counterpart starting element of the internal combustion engine; an electromagnetic switch including: a coil carrier having a carrier wall which extends in an axial direction and which encloses a cavity in the coil carrier; a coil winding having a coil wire wound on a side of the carrier wall facing away from the cavity and which, during operation, is flowed through by an electrical current and provides a magnetic field within the cavity; a piston which is axially adjustable in the cavity and, when the coil winding is not in operation, is disposed in a passive position and, during operation of the coil winding, is adjusted axially in a direction of a core; the piston and the core defining an axial gap therebetween in the cavity when in the passive position of the piston; the coil wire, in an axially extending first winding section, wound in a first winding direction around the carrier wall; the coil wire, in an axially extending second winding section, wound in a second winding direction opposite the first winding direction around the carrier wall; and at least one winding of the second winding section axially overlapping the axial gap; wherein the piston is connected to the starting element such that the piston, during the axial adjustment in the direction of the core, adjusts the starting element in the direction of the counterpart starting element.
20. An electromagnetic switch for a starting device of an internal combustion engine, comprising: a coil carrier having a carrier wall which extends in an axial direction and which encloses a cavity in the coil carrier; a coil winding having a coil wire wound on a side of the carrier wall facing away from the cavity and which, during operation, is flowed through by an electrical current and provides a magnetic field within the cavity; a piston which is axially adjustable in the cavity and, when the coil winding is not in operation, is disposed in a passive position and, during operation of the coil winding, is adjusted axially in a direction of a core; in the passive position of the piston, the piston and the core defining an axial gap therebetween in the cavity; the coil wire, in an axially extending first winding section, wound in a first winding direction around the carrier wall; the coil wire, in an axially extending second winding section, wound in a second winding direction opposite the first winding direction around the carrier wall; wherein at least one winding of the second winding section axially overlaps the axial gap; and wherein a side of the at least one winding facing radially toward the axial gap, which axially overlaps the axial gap, is free from the coil wire.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) In the drawings, in each case schematically:
(2) FIG. 1 shows a longitudinal section through an electromagnetic switch,
(3) FIG. 2 is an enlarged illustration from FIG. 1,
(4) FIGS. 3 through 18 each show a longitudinal section through the electromagnetic switch, in each case in a different exemplary embodiment,
(5) FIG. 19 shows a longitudinal section through a starting device of an internal combustion engine,
(6) FIG. 20 shows a side view of the electromagnetic switch from FIG. 3,
(7) FIG. 21 shows an isometric view of the single coil carrier from FIG. 20,
(8) FIG. 22 shows a side view of the coil carrier in the case of a different exemplary embodiment.
DETAILED DESCRIPTION
(9) An electromagnetic switch 1, hereinafter also referred to for short as switch 1, as shown for example in FIGS. 1 to 9, is commonly a constituent part of a starting device 2 of an internal combustion engine 3, as shown by way of example in FIG. 9. The starting device 2 furthermore has an electrically operated motor 4 or electric motor 4 which, during operation, transmits a torque to a starting element 6 of the starting device 2, for example via a shaft 5, wherein the starting element 6 transmits said torque for starting the internal combustion engine 3 to a counterpart starting element 7 (see FIG. 19). For the transmission of the torque, the starting element 6, which is formed for example as a pinion 8, and the counterpart starting element 7, which is formed for example as a ring gear 9, are placed in engagement. When the internal combustion engine 3 has been started, the engagement of the starting element 6 with the counterpart starting element 7 is released. For this purpose, the starting element 6 is adjustable relative to the counterpart starting element 8. This adjustment is realized by means of the electromagnetic switch 1, which adjusts the starting element 6 via a coupling element 10, for example a lever 11. The coupling element 10 is connected in terms of drive to a piston 12 of the starting device 2 and is mounted such that an adjustment of the piston 12 in one axial direction 17 axially adjusts the starting element 6 in the opposite direction. For this purpose, the piston 12 is adjustable in the starting device 2 in the axial direction 17, and is thus axially adjustable, wherein the adjustment of the piston 12 in the axial direction 17 for the displacement of the starting element 6 in the direction of the counterpart starting element 7 is realized by means of a coil winding 13, and the adjustment of the starting element 6 away from the counterpart starting element 7 is realized by means of at least one spring 14 which acts on the piston 12. In the example shown, the piston 12 is in this case connected by means of a bolt 15, which is attached to the piston 12, to the coupling element 10.
(10) The switch 1 has a coil carrier 16 which has a carrier wall 19, which carrier wall extends in cylindrical form in an axial direction 17 and encloses a cavity 18, and on which carrier wall the coil winding 13 is wound. In the example shown, the coil winding 13 extends from a radially projecting first end wall 39 to a radially projecting second end wall 40, which is situated axially opposite the first end wall 39, of the coil carrier 16. The end walls run in each case in closed form in a circumferential direction and are of disk-like form. Here, the coil winding 13 forms an attracting coil 20 of the switch 1. In the examples shown, the switch 1 furthermore has a holding coil 21, which is wound radially outside the coil winding 13. The coil winding 13 and the holding coil 21 are arranged in a housing 50 of the switch 1. When electrically energized, the coil winding 13 or the attracting coil 20 serves for the adjustment of the piston 12 in the direction of a core 22, which, like the piston 12, is accommodated in the cavity 18 but is fixed therein and is thus axially non-adjustable. For this purpose, during operation, that is to say when energized, the coil winding 13 and thus the attracting coil 20 and the holding coil 21 generate, within the cavity 18, a magnetic field which exerts an adjusting force on the piston 12 and thus adjusts said piston axially in the direction of the core 22. For this purpose, the piston 12 is at least partially, preferably entirely, ferromagnetic. With the holding coil 21, it is possible to hold the piston 12 in its respectively present position. The attracting coil 20 and the holding coil 21 in this case generate such a magnetic field, which subjects the piston 2 to an adjusting force opposed to the spring force of the at least one spring 14, that, for the adjustment of the piston 12 in the direction of the core 22, the spring force is overcome, and for the holding of the piston 12 in its present position, a compensation of the spring force is realized. The piston 12 is mechanically connected, by means of a connecting element 23 which is of rod-like form in the example shown, to a switching element 24. During the adjustment of the piston 12 in the direction of the core 12, which is likewise at least partially ferromagnetic, the switching element 24 is adjusted in the direction of electrical contacts 25, wherein the switching element 24, when it makes contact with the electrical contacts 25, electrically connects said contacts 25 to one another. Thus, an electrical connection is produced between two lines 26 by means of which electricity is supplied to the electric motor 4. Here, for the starting of the internal combustion engine 3, the coils 20, 21 are electrically energized, and here, adjust the piston 12 in the direction of the core 22 until the switching element 24 produces an electrical connection between the electrical contacts 25. In this state, the electrical energization of the attracting coil 13 is stopped, and the holding coil 21 is electrically energized, in order to hold the piston 12 in position and thus maintain an electrical connection between the lines 26 that supply electricity to the electric motor 4. In this position, it is furthermore the case that the starting element 6 and the counterpart starting element 7 are in engagement, such that the electric motor 4 starts the internal combustion engine 3. When the internal combustion engine 3 has been started, the supply of electricity to the starting device 1 is stopped, such that no magnetic field is generated, and the spring force adjusts the piston 12 back into a passive position 27, which is illustrated in FIGS. 1 to 19. The passive position 27 of the piston 12 is thus the position in the absence of electrical energization of the electromagnetic switch 1. The starting device 2 is in this case connected such that the electrical current that flows through the switch 1 corresponds to the current by means of which the electric motor 4 is driven. The magnetic field which is generated by the attracting coil 20, and thus the adjusting force that acts on the piston 12, and also the torque that is transmitted by means of the electric motor 4 to the starting element 6, are thus dependent on said electrical current. Here, there is a demand firstly to keep the torque of the electric motor 4 sufficiently high, or to increase said torque, such that the internal combustion engine 3 can be started in simplified fashion. Secondly, it is sought to reduce the adjusting force with which the piston 12 is adjusted in the direction of the core 22, in order to reduce damage to the starting element 6 and/or to the counterpart starting element 7, such as can arise during the production of the engagement of the starting element 6 with the counterpart starting element 7.
(11) To reduce the adjusting force, the coil winding 13 which forms the attracting coil 20 is wound at least partially oppositely to the winding direction 28 with which the coil winding 13, when electrically energized, adjusts the piston 12 in the direction of the core 22, hereinafter referred to as first winding direction 28, specifically is wound at least partially in a second winding direction 29. A coil wire 30 of the coil winding 13 is thus wound partially in the first winding direction 28 and partially in the second winding direction 29, wherein the different winding directions 28, 29 are illustrated or indicated in FIGS. 1 and 2 and 6 to 9 by means of different hatchings of the coil winding 13.
(12) In the examples shown, the coil wire 30 of the coil winding 13 is wound in multiple radially successive rows 31. Here, the row 31′ situated closest to the cavity 18 is referred to as first row 31′.
(13) In the passive position 27, the piston 12 is separated from the core 22 by an axial gap 32 running in an axial direction 17, which axial gap extends axially between a face side 33, facing toward the core 22, of the piston 12, hereinafter also referred to as piston face side 33, and a face side 34, facing toward the piston 12, of the core 22, hereinafter also referred to as core face side 34. Here, according to the invention, at least one of the windings wound in the second winding direction 29 is arranged so as to axially overlap the axial gap 32. Here, the coil wire 30 is, in a first axial winding section 35, wound in the first winding direction 28 around the carrier wall 19 and, in a second axial winding section 36, is wound in the second winding direction 29 around the carrier wall 19.
(14) Here, the first winding section 35 is to be understood to mean that section of the coil winding 13 which is wound in the first winding direction 28 and thus extends axially. The second winding section 36 is that section of the coil winding 13 in which the coil wire 30 is wound in the second winding direction 29. Accordingly, the second winding section 36 extends axially. It is also possible for the second winding section to extend across multiple radially successive rows 31 of the coil winding 13.
(15) In the examples shown in FIGS. 1 to 5 and 8 and 9 and also 11 and 12, the coil wire 30 is furthermore, in a third axial winding section 37, likewise wound in the first winding direction 28 around the carrier wall 19, wherein the second winding section 36 is arranged axially between the first winding section 35 and the third winding section 37. The third winding section 37 thus corresponds to the first winding section 35, with the difference that, in the row 31 in which the second winding section 36 is arranged, the first winding section 35 and the third winding section 37 are arranged on axially mutually averted sides of the second winding section 36.
(16) The transition between the first winding direction 28 and the second winding direction 29 is, in the examples of FIGS. 3 to 5 and also 7, 8 and 12, separated by means of a separating body 38 of the coil carrier 16, which separating body projects radially from the carrier wall 19 and extends in a circumferential direction. The separating bodies 38 are arranged axially between the end walls 39, 40 and are arranged so as to be axially spaced apart from one another.
(17) In the example shown in FIGS. 1 and 2, the second winding section 36 corresponds, in its length running in the axial direction 17, substantially to the axially running length of the axial gap 32, wherein, in the passive position 27, the second winding section 36 and the axial gap 32 are arranged substantially in alignment. Here, all of the windings of the second winding section 36 are arranged so as to axially overlap the axial gap 32.
(18) The example shown in FIG. 3 differs from the example shown in FIG. 2 in particular in that the windings wound in the second winding direction 29, and thus the second winding section 36, have been relocated axially toward the piston 12, such that the second winding section 36 partially axially overlaps the axial gap 32 and partially axially overlaps the piston 12.
(19) FIG. 4 shows an example in which, in relation to that in FIGS. 1 and 2 and by contrast to the example shown in FIG. 3, the second winding section 36 has been relocated axially toward the core 22, such that the windings, wound in the second winding direction 29, of the second winding section 36 partially axially overlap the axial gap 32 and partially axially overlap the core 22.
(20) The exemplary embodiment shown in FIG. 5 differs from the exemplary embodiment shown in FIGS. 1 and 2 in that the axial length of the second winding section 36, in which the coil wire 30 is wound in the second winding direction 29, is greater than the axial extent of the axial gap 32. Furthermore, the second winding section 36 is arranged so as to extend over the entire axial gap 32, and furthermore so as to partially axially overlap the piston 12 and partially axially overlap the core 22.
(21) In the examples shown in FIGS. 3 to 5, the transition between the first winding direction 28 and the second winding direction 29 is separated in each case by a separating body 38 of the coil carrier 16, which separating body projects radially from the carrier wall 19 and extends in the circumferential direction and is discontinuous. In these examples, the coil body 16 therefore has two such separating bodies 38, which are axially spaced apart from one another, wherein one of the separating bodies 38 separates the second winding section 36 axially from the first winding section 35 and the other separating body 38 separates the second winding section 36 axially from the third winding section 37. The separating bodies 38 are arranged axially between the end walls 39, 40 and are arranged so as to be axially spaced apart from one another.
(22) FIG. 6 shows an exemplary embodiment in which the coil wire 30 of the coil winding 13 is arranged not in the row 31 situated radially closest to the cavity 18 or to the radial gap 32 but in the row 31 situated radially furthest remote from the axial gap 32 or the cavity 18, hereinafter also referred to as last row 31a. In comparison with the example shown in FIGS. 1 and 2, the second winding section 36 has been relocated toward the core 22, and extends axially from the first end wall 39 to the second piston face side 33. The second winding section 36 thus axially entirely overlaps the core 22 and the axial gap 32. In this example, it is furthermore the case that no third winding section 37 is provided.
(23) The exemplary embodiment shown in FIG. 7 differs from the example shown in FIG. 6 in that the second winding section 36 with the coil wire 30 wound in the second winding direction 29 is arranged in the first row 31′ of the coil winding 13, and thus in the row 31 situated radially closest to the cavity 18 and to the axial gap 32. In this exemplary embodiment, it is furthermore the case that the coil carrier 16 is equipped with a separating body 38 which separates the second winding section 36 axially from the first winding section 35, wherein the first winding section 35 extends in the first row 31′ from the separating body 38 to the second end wall 40.
(24) FIG. 8 shows a further exemplary embodiment. This exemplary embodiment differs from the exemplary embodiment shown in FIG. 5 in that a pitch of the coil wire 30 in the second winding section 36 wound in the second winding direction 29 varies axially. This means that a spacing of successive windings of the second winding section 36 changes in the axial direction 17, wherein, to illustrate the varying pitch of the coil wire 30, the coil wire 30 is shown in section, rather than by hatching as in FIGS. 1 to 7 and also 9 to 19. In the example shown, the pitch decreases toward the core 22, such that the coil wire 30 is wound more densely, that is to say with an axially decreasing spacing, toward the core 22.
(25) FIG. 9 shows a further exemplary embodiment of the switch 1. This exemplary embodiment differs from the example shown in FIG. 3 in that the switch 1 additionally has a ferromagnetic bypass body 41, which encloses the cavity 18, in the example shown the axial gap 32, and is arranged radially between the cavity 18, in the example shown the axial gap 32, and the coil winding 13. Here, the bypass body is arranged so as to axially overlap the axial gap 32, and at least one winding of the second winding section 36 is arranged so as to axially overlap the bypass body 41. The bypass body 41 diverts the magnetic field or the magnetic flux in the cavity 18 between the piston 12 and the core 22, wherein the bypass body 41 has a saturation limit. The at least one winding, which axially overlaps the bypass body 41, of the second winding section 36 reduces the magnetic flux through the bypass body 41, such that, ultimately, an increased magnetic flux can flow through the bypass body 41, until the latter reaches the saturation limit. This directly leads to a reduction of the magnetic field or of the magnetic flux between the piston 12 and the core 22, such that the adjusting force is correspondingly reduced.
(26) In the example of FIG. 9, the second winding section 36 and the bypass body 41 have a substantially equal extent in the axial direction 17, and are arranged in alignment in a radial direction 51 running transversely to the axial direction 17. In the example shown in FIG. 9, by comparison with the example shown in FIG. 3, the coil body 16 furthermore has no separating body 38, wherein a separating body 38 of said type is also conceivable.
(27) The exemplary embodiment shown in FIG. 10 differs from the example shown in FIG. 9 in that the second winding section 36 has been extended toward the first end wall 39, such that the second winding section 36 extends as far as the first end wall 39. Thus, in this example, the coil winding 13 has the second winding section 36 and the first winding section 35. The second winding section 36 thus also axially overlaps the core 22.
(28) FIG. 11 shows a further exemplary embodiment of the switch 1. This exemplary embodiment differs from the exemplary embodiment shown in FIG. 9 in that the bypass body 41 is dimensioned to be radially larger, and is thus thicker. Furthermore, by comparison with the example shown in FIG. 9, the second winding section 36 has been relocated toward the core 22. Both the bypass body 41 and the second winding section 36 are in each case arranged so as to axially overlap one another and the axial gap 32. The carrier wall 19 is equipped with a radial step, such that said carrier wall, in an axially running first wall section 42, has an outer diameter 43, hereinafter referred to as first outer diameter 43, which is smaller than an outer diameter 44 in an axially adjoining second wall section 45, hereinafter referred to as second outer diameter 44. Therefore, the carrier wall 19 has, in the first wall section 42, a chamber 46 which is recessed toward the cavity 18. In the example shown, the chamber 46 is filled with coil wire 30 wound in the first winding direction 18. Axially adjacent to the chamber 46, the coil wire 30 is wound in the second winding direction 29, such that the second winding section 36 is wound on the second wall section 45. That side of the second winding section 36 which is axially averted from the chamber 6 is adjoined by the third winding section 37. In this exemplary embodiment, too, the second winding section 36 is, in the region in which it is arranged, arranged radially as close as possible to the axial gap 32. This means that that side of the second winding section 36 which faces radially toward the cavity 18 or the axial gap 32 is free from the coil wire 30.
(29) A further exemplary embodiment of the switch 1 is illustrated in FIG. 12. This exemplary embodiment differs from the example shown in FIG. 11 in that the bypass body 41 extends toward the piston 12 and, here, is formed so as to be larger in the axial direction 17 than the second winding section 36. Furthermore, the coil carrier 16 is equipped with two separating bodies 38, which separate the second winding section 36 in each case from the third winding section 37 or from the first winding section 35.
(30) In the examples shown, it is furthermore the case that the bypass body 41 is always axially spaced apart from the core 22.
(31) In the examples shown in FIGS. 9 to 12, the bypass body 41 is accommodated by means of the coil carrier 16. For this purpose, the coil body 16 has an axial shoulder 49 which extends in a circumferential direction. Here, the bypass body 41 is surrounded in form-fitting fashion by the carrier wall 19 or the shoulder 49. In the example shown in FIGS. 11 and 12, the chamber 46, or the difference between the outer diameters 43, 44, is also realized by means of said shoulder 49.
(32) In the example of FIG. 12, the bypass body 41 is, on the side averted from the shoulder 49, furthermore surrounded axially in form-fitting fashion by the housing 50. In other words, on the side averted from the shoulder 49, the bypass body 41 abuts axially against the housing 50. By contrast, in the other examples, the bypass body 41 is axially spaced apart from the housing 50.
(33) FIGS. 13 to 18 show examples in which the coil wire 30 has a non-ferromagnetic section 47, composed for example of copper, aluminium and the like, and a ferromagnetic section 48, composed for example of iron, nickel and the like. In the examples shown in FIGS. 13 and 14, the second winding section 36 is formed by the ferromagnetic wire section 48, hereinafter also referred to as second wire section 48, whereas the non-ferromagnetic section 47 of the coil wire 30, hereinafter referred to as first wire section 47, is wound in the first winding direction 28. Here, the second wire section 48 is wound first, and the first wire section 47 is wound subsequently, onto the coil carrier 16.
(34) In the examples of FIGS. 13 and 14, this has the result that the first wire section 47 is wound entirely onto the second wire section 48. In other words, the first wire section, which is wound in the first winding direction 28, is wound onto the second wire section 48, which is wound in the second winding direction 29 and which forms the second winding section 36. Here, the ferromagnetic second wire section 48 is illustrated with denser hatching than the non-ferromagnetic first wire section 47 of the coil wire 30 of the coil winding 13. In FIG. 13, the second wire section 48 and thus the second winding section 36 are arranged in the chamber 46 and fill the chamber 46. In the example of FIG. 14, the second winding section 36 extends from the first end wall 39 to the second end wall 40. Furthermore, in these examples, multiple rows 31 of the second winding section 36 are provided. In FIG. 13, the second winding section 36 and thus the second wire section 48 are furthermore spaced apart axially with respect to the core 22. In FIG. 14, the first winding section 36, like the second winding section 35, extends axially between the end walls 39, 40 of the winding carrier 16.
(35) FIG. 15 shows a further exemplary embodiment of the switch 1. This exemplary embodiment differs from the examples shown in FIG. 14 in that the second winding section 36 is wound from the second wire section 48 on that side of the first wire section 47, and thus of the first winding section 35, which is radially averted from the cavity 18 or from the axial gap 32.
(36) In the examples shown in FIGS. 13 to 15, the respective row 31 of the coil winding 13 is thus wound either with the non-ferromagnetic first wire section 47 or with the ferromagnetic second wire section 48.
(37) FIGS. 16 to 18 show examples in which both the first wire section 47 and the second wire section 48 are wound within one row 31 of the coil winding 13.
(38) In the example shown in FIG. 17, firstly, multiple rows 31 are wound with the ferromagnetic second wire section 48 in the first winding direction 28, and, subsequently, multiple rows 31 of the non-ferromagnetic first wire section 47 are wound in the first winding direction 48. In the adjoining row 31, firstly, the ferromagnetic second wire section 48 is wound in the first winding direction, and subsequently, the non-ferromagnetic first wire section 47 is wound in the second winding direction 29. Here, the second winding section 36 runs from the first end wall 39 and overlaps the axial gap 32 and, in part, the piston 12.
(39) In the exemplary embodiment shown in FIG. 16, in the first row 31′, firstly, the ferromagnetic second wire section 48 is wound in the second winding direction 29, and subsequently, the non-ferromagnetic first wire section 47 is wound in the first winding direction 28. The two adjoining rows 31 are also wound with the ferromagnetic second wire section 48 in the first winding direction 28. The following rows 31 are also wound with the non-ferromagnetic first wire section 47 in the first winding direction 28. The second winding section 36 however in this case extends, as in the example of FIG. 17, axially from the first end wall 39 of the coil carrier 16 to the piston face side 33.
(40) The exemplary embodiment shown in FIG. 18 differs from the exemplary embodiment shown in FIG. 17 in that the coil carrier 16 has a chamber 46, wherein the ferromagnetic second wire section 48 in the first winding direction 28 completely fills the chamber 46, such that, outside the chamber 46, the non-ferromagnetic first wire section 47 is wound firstly in the first winding direction 28 and subsequently in the second winding direction 29. Here, FIG. 18 illustrates only the radially upper half of the section.
(41) In all of the examples, the coil winding 13 always has fewer windings in the second winding direction 29 than in the first winding direction 28.
(42) The respective coil body 16 may, for example in an end wall 39, 40, in the examples shown in the first end wall 39, have two leadthroughs 52, formed as radial apertures, for the leadthrough of the coil wire 30 (see FIGS. 20 to 22).
(43) An example of the coil body 16 with at least one separating body 38 will be discussed in more detail on the basis of FIGS. 20 to 22, which in this case involve, merely by way of example, a coil body 16 of the switch 1 from FIG. 3. It is however self-evident that the features are correspondingly transferable to the other coil bodies 16.
(44) Here, FIG. 20 illustrates a side view of the electromagnetic switch 1 only with the coil wire 30 in the first row 31′ and the coil carrier 16, and FIG. 21 illustrates an isometric view of the coil carrier 16. It can be seen that, in addition to the separating sections 38 visible in FIG. 3, which are arranged between the end walls 39, 40 and which will hereinafter also be referred to as intermediate separating bodies 38′, a separating body 38 is also arranged axially on the end side of the carrier wall 19, and therefore in the example shown so as to axially adjoin the end wall 39, which will hereinafter also be referred to as end carrier wall 38″. The respective separating body 38 extends in the circumferential direction and has, in the circumferential direction, a recess 53, which separates a first separating body end 54 from a second separating body end 55 of the separating body 38 in the circumferential direction. The respective intermediate separating body 38′ in this case separates two wall segments 56 of the carrier wall 19 from one another in the axial direction 17, wherein the wall segments 56 that are separated in this way are connected to one another by means of the recess 53 of the separating body 38′. The recess 53 of the end separating body 38″ is formed so as to transition into the leadthrough 52. Here, the coil wire 30 is introduced into the coil carrier via one of the leadthroughs 52 and via the recess 53 of the end separating body 38″, wherein the winding of the coil wire 30 starts or ends in the region of the recess 53 of the end separating body 38″. In the example shown, the coil carrier 16 has two intermediate separating bodies 38″. A first of the separating bodies 38′ in this case separates a first wall segment 56′ of the carrier wall 19 axially from a second wall segment 56″ of the carrier wall. Furthermore, a second of the intermediate separating bodies 38′ separates the second wall segment 56″ axially from a third wall segment 56′″ of the carrier wall 19. The first winding section 35 is wound in the first winding direction 28 on the first wall segment 56′, the second winding section 36 is wound in the second winding direction 29 on the second wall segment 56″, and the third winding section 37 is wound in the first winding direction 28 on the third wall segment 56′″. Here, the coil wire 30 is led through the recess 53 of the respective intermediate separating body 38′, such that a reversal of the winding direction 28, 29 is realized via the recess 53. Here, an axially running body width 57 of the respective separating body 38 decreases between one of the separating body ends 54, 55 and the other separating body end 54, 55, and thus along the circumferential direction. In the example shown, the body width 57 decreases continuously from one of the separating body ends 54, 55 to the other separating body end 54, 55.
(45) In the example shown, the body widths 57 of axially successive separating bodies 38 decrease alternately from the first body end 54 to the second body end 55 and vice versa. In the example specifically shown, the body width 57 of the end separating body 38″ decreases continuously from the first separating body end 54 to the second separating body end 55. In the case of the intermediate separating body 38′ which follows the end separating body 38″ and which separates the first wall segment 56′ from the second wall segment 56″, the body width 57 increases continuously from the first separating body end 54 to the second separating body end 57. In the case of the axial subsequent intermediate separating body 38′, which separates the second wall segment 56″ from the third wall segment 56′″, the body width 57 decreases continuously from the first separating body end 54 to the second separating body end 55. Thus, despite alternating winding directions 28, 29, dense and in particular gapless winding of the coil wire 30 on the respective wall segment 56 is possible. The decreasing body with 57 of the respective separating body 38 is, in the examples shown, realized by means of a profile, which has an angle α in the circumferential direction, of at least one axial flank 58 of the respective separating body 38. In the case of the end separating body 38″ that is shown, at least one of the flanks 58 has such a profile, whereas, in the case of the intermediate separating bodies 38′, both flanks 58 have such a profile.
(46) It can be seen in particular from FIG. 20 that a spacing 59, running in the circumferential direction, between the separating body ends 54, 55 of the respective separating body 38, in particular of the respective intermediate separating body 38′, is dimensioned and configured such that the coil wire 30, as it passes through the recess 53 and reverses the winding direction 28, 29, fills the recess 53 in substantially form-fitting fashion in the circumferential direction. It can also be seen that, in the respective recess 53, the separating body end 54, 55 against which the coil wire 30 bears owing to the inner contour 60 shaped by the reversal of the winding direction 28, 29 is that separating body end 54, 55 which has the smaller or minimum body width 57. In the example shown, therefore, in the case of the separating body 38′ which separates the first wall segment 56′ from the second wall segment 56″, the first separating body end 54 is that which has the relatively small, in particular minimum, body width 57, whereas, in the case of the other intermediate separating body 38′, the second separating body end 55 has the relatively small, in particular minimum, body width 57 of the intermediate separating body 38′. This, too, leads to easier winding of the coil wire 30, and to improved stability of the coil winding 30. It can also be seen that the separating body end 54, 55 against which the coil wire 30 bears with the inner contour 60 is of rounded form.
(47) It can also be seen from FIG. 20 that a radially running extent of the respective separating body 38 corresponds substantially to a radial extent of the coil wire 30, such that the separating bodies 38 are aligned axially with the illustrated first row 31′ of the coil wire 30, such that the row 31 of the coil wire 30 wound onto the first row 31′ can be wound in gapless and dense fashion. In the examples shown, it is thus the case that a radial separating body height 61 (see FIG. 22) of the respective separating body 38 corresponds substantially to the radial dimension or extent of the coil wire 30.
(48) A further exemplary embodiment of the coil body 16 is illustrated in FIG. 22. This exemplary embodiment differs from the exemplary embodiment shown in FIGS. 20 and 21 in that the flanks 58 of the separating bodies 38 each run in radially inclined fashion, and in the example shown each run so as to be inclined radially toward the other flank 58. The respective flank 58 thus forms an angle β with the radial direction 51. Consequently, the body width 57 of the respective separating body 38 also decreases in the radial direction 51 away from the cavity 18. This permits, in particular, a more gapless and denser winding of the coil wire 30 onto the carrier wall 19, and simplified production of the coil carrier 16.
(49) In the examples shown in FIGS. 20 to 22, the intermediate separating bodies 38′ are arranged such that the second wall segment 56″ is spaced apart axially from the core 22 and has been relocated toward the piston 12. Furthermore, the third wall segment 56′″ is axially smaller than the first wall segment 56′ and than the second wall segment 26″. Accordingly, the second winding section 36 of the coil wire 30 wound in the second winding direction 29 is arranged so as to be spaced apart axially from the core 22 and so as to overlap the piston 12. It is self-evidently possible for the respective separating bodies 38, in particular intermediate separating bodies 38′, to also run in an axially offset manner in order to change the position of the corresponding wall segments 56 or winding sections 35, 36, 37 relative to the core 22, to the piston 12 and to the axial gap 32.
