Abstract
An insulation body for an electrical machine may include a plurality of outer walls. The outer walls may be composed of a plastic. The outer walls may define a body interior having at least one winding zone configured to receive a stator winding, and at least one channel zone for receiving a cooling channel.
Claims
1. An insulation body for an electrical machine, the insulation body comprising: a plurality of outer walls composed of a plastic, the outer walls defining a body interior having (i) at least one winding zone configured to receive a stator winding, (ii) and at least one channel zone for receiving a cooling channel.
2. The insulation body according to claim 1, further including at least one separating wall composed of electrically insulating plastic, the at least one separating wall configured to subdivide the body interior into the at least one winding zone and the at least one channel zone.
3. The insulation body according to claim 2, wherein the outer walls and the at least one separating wall extend along an axial direction, and wherein in a cross section perpendicular to the axial direction the at least one winding zone and the channel zone are arranged adjacent to one another.
4. The insulation body according to claim 3, wherein the at least one channel zone includes a first and a second channel zone, the first channel zone configured to receive a first cooling channel and the second channel zone configured to receive a second cooling channel, and wherein in the cross section perpendicular to the axial direction the at least one winding zone is arranged between the first and second channel zones and is separated therefrom by two separating walls.
5. The insulation body according to claim 4, wherein the first and second winding zones are separated from one another by a phase insulation composed of the plastic.
6. The insulation body according to claim 5, wherein the phase insulation is formed by one of the at least one separating wall.
7. The insulation body according to claim 1, wherein the insulation body is injection-moulded or extruded.
8. The insulation body according to claim 3, wherein the insulation body has a shape of at least one of a parallelepiped, a trapezium, and a rectangle in a cross section perpendicular to the axial direction.
9. The insulation body according to claim 1, wherein an axial stop is formed on at least one of the outer walls at an axial end of the insulation body.
10. The insulation body according to claim 9, wherein the axial stop is formed as an outwardly protruding wall collar on at least one of the outer walls (101a-d) of the insulation body (100).
11. The insulation body according to claim 3, wherein a spacer structure is provided on at least two of the outer walls, and wherein the spacer structure is insertable into a stator slot of a stator of an electrical machine at a defined distance.
12. The insulation body according to claim 11, wherein the spacer structure is formed by projections arranged on an outer side of the outer walls facing away from the body interior.
13. The insulation body according to claim 12, wherein the projections are formed integrally with the outer walls.
14. The insulation body according to claim 11, wherein the insulation body is configured to be insertable into the stator slot along the axial direction.
15. The insulation body according to claim 14, wherein the insulation body is configured to be disposed within the stator slot by an interference fit or a transition fit.
16. The insulation body according to claim 1, wherein the insulation body is formed from a dimensionally stiff material.
17. The insulation body according to claim 6, wherein the insulation body is reinforced the separating walls.
18. The insulation body according to claim 1, wherein the insulation body is produced in a non-forming fashion.
19. The insulation body according to claim 3, wherein a cross section of the body interior of the insulation body defined perpendicular to the axial direction is constant along an entire length of the insulation body.
20. The insulation body according to claim 3, wherein a cross section of the insulation body defined perpendicular to the axial direction is both axially symmetrical and point-symmetrical over an entire length of the insulation body.
21. The insulation body according to claim 1, wherein the outer walls are connected to one another without seams or joints.
22. An electrical machine for a motor vehicle, comprising: a rotor rotatable about a rotation axis defining an axial direction of the electrical machine; a stator having electrically conductive stator windings; and at least one cooling channel through which a coolant can flow to cool the stator windings, wherein the stator has stator teeth extending along the axial direction and arranged at a distance from one another along a circumferential direction of the rotor, the stator teeth protruding radially inward from a stator body of the stator, and the stator teeth configured to carry the stator windings, wherein an interspace is formed between two of the stator teeth, wherein an insulation body is arranged in the interspace, wherein one of the stator windings is arranged in the an winding zone of the insulation body and a cooling channel for a coolant to flow through is arranged in a channel zone of the insulation body.
23. The electrical machine according to claim 22, wherein the insulation body is inserted into the interspace.
24. The electrical machine according to claim 23, wherein an axial direction of the insulation body is parallel to the axial direction of the electrical machine.
25. The electrical machine according to claim 22, wherein the electrical machine is disposed within a motor vehicle.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0069] In the figures, schematically in each case:
[0070] FIG. 1 shows one example of an insulation body according to the invention in an isometric illustration,
[0071] FIG. 2 shows the insulation body from FIG. 1 in a sectional illustration,
[0072] FIG. 3 shows one example of an electrical machine according to the invention comprising an insulation body from FIGS. 1 and 2,
[0073] FIG. 4 shows the stator of the electrical machine in accordance with FIG. 3 in a cross section perpendicular to the rotation axis of the rotor,
[0074] FIG. 5 shows a detailed illustration of the stator from FIG. 4 in the region of an interspace between two stator teeth which are adjacent in the circumferential direction,
[0075] FIGS. 6, 7 show variants of the example from FIG. 5.
DETAILED DESCRIPTION
[0076] FIGS. 1 and 2 illustrate one example of an insulation body 100 according to the invention composed of a plastic 11 for a stator of an electrical machine. Expediently, the insulation body 100 is an injection-moulded part. The insulation body 100 can moreover be a monolithic body and, alternatively or additionally, an extruded body.
[0077] FIG. 1 shows the insulation body 100 in an isometric illustration, and FIG. 2 shows it in a sectional illustration. The insulation body 100 delimits a body interior 104. In accordance with FIG. 1, the insulation body 100 has the geometric shaping of a parallelepiped. This parallelepiped is formed by four outer walls 101a, 101b, 101d composed of plastic 11. The four outer walls 101a-d extend along an axial direction a. In the cross section perpendicular to the axial direction a as shown in FIG. 2, the outer walls 101a-d form two narrow sides 102a, 102b and two broad sides 103a, 103b. The two narrow sides 102a, 102b are opposite one another. Analogously, the two broad sides 103a, 103b are opposite one another. The two narrow sides 102a, 102b are preferably arranged orthogonally to the two broad sides 103a, 103b.
[0078] As revealed by FIGS. 1 and 2, the body interior 104 is subdivided into a first and a second winding zone 106a, 106b and into a first and a second channel zone 107a, 107b by separating walls 105a, 105b, 105c composed of plastic 11, which likewise extend along the axial direction a. The first separating wall 105a is thus arranged between the first winding zone 106a and the first channel zone 107a. The second separating wall 105b is arranged between the second winding zone 106b and the second channel zone 107b.
[0079] The third separating wall 105c is arranged between the first and second winding zones 106a, 106b. In the cross section shown in FIG. 2, the three separating walls 105a, 105b, 105c in each case extend parallel to one another and additionally extend parallel to the two outer walls 101c, 101d. Accordingly, the three separating walls 105a, 105b, 105c extend orthogonally to the two outer walls 101a, 101b.
[0080] The two channel zones 107a, 107b serve to receive a first and respectively a second cooling channel (not shown in FIGS. 1 and 2). Analogously, the two winding zones 106a, 106b serve to receive conductor elements of the stator winding (not shown in FIGS. 1 and 2).
[0081] As revealed by FIGS. 1 and 2, the two winding zones 106a, 106b are arranged adjacent to one another and next to one another. The two winding zones 106a, 106b are additionally arranged between the two channel zones 107a, 107b. Furthermore, the two winding zones 106a, 106b are electrically isolated and spatially separated from one another by means of a phase insulation 108 composed of plastic 11. The phase insulation 108 is formed by the separating wall 105c already presented.
[0082] In accordance with FIG. 1, an axial stop 109 can be formed at an axial end 111 of the four outer walls 101a-101d of the insulation body 100.
[0083] The axial stop 109 can be formed as an outwardly protruding, partly or completely circumferential wall collar 110 shaped integrally on all four outer walls 101a-d of the insulation body 100.
[0084] An electrical machine 1 comprising the insulation body 100 presented above is presented below with reference to FIGS. 3 and 4. The electrical machine 1 is dimensioned such that it can be used in a vehicle, preferably in a road vehicle. FIG. 3 shows the machine 1 in a longitudinal section, and FIG. 4 shows it in a cross section.
[0085] The electrical machine 1 comprises a rotor 3, which is merely illustrated roughly schematically in FIG. 3, and a stator 2. For elucidation, FIG. 4 illustrates the stator 2 in a cross section perpendicular to the rotation axis D along the sectional line II-II from FIG. 3 in a separate illustration. In accordance with FIG. 3, the rotor 3 has a rotor shaft 31 and can have a plurality of magnets, not illustrated more specifically in FIG. 3, the magnetic polarization of which magnets alternates along the circumferential direction U. The rotor 3 is rotatable about a rotation axis D, the position of which is defined by the central longitudinal axis M of the rotor shaft 31. The rotation axis D defines an axial direction A extending parallel to the rotation axis D. A radial direction R is perpendicular to the axial direction A. A circumferential direction U rotates about the rotation axis D.
[0086] As can be discerned from FIG. 3, the rotor 3 is arranged in the stator 2. Consequently, the electrical machine 1 shown here is a so-called internal rotor. However, a realization as a so-called external rotor is also conceivable, in which the rotor 3 is arranged outside the stator 2. The rotor shaft 31 is mounted in a first shaft bearing 32a and, axially at a distance therefrom, in a second shaft bearing 32b rotatably about the rotation axis D on the stator 2.
[0087] The stator 2 additionally comprises, in a known manner, a plurality of stator windings 6, which are electrically energizable for the purpose of generating a magnetic field. Magnetic interaction between the magnetic field generated by the magnets of the rotor 3 and the magnetic field generated by the electrically conductive stator windings 6 causes the rotor 3 to rotate.
[0088] The cross section in FIG. 2 reveals that the stator 2 can have a ring-shaped stator body 7, for example composed of iron. In particular, the stator body 7 can be formed from a plurality of stator body plates (not shown) which are stacked one on top of another along the axial direction A and are adhesively bonded to one another. A plurality of stator teeth 8 are integrally formed on the stator body 7 radially on the inside, which stator teeth extend along the axial direction A, protrude away from the stator body 7 radially inward and are arranged at a distance from one another along the circumferential direction U. Each stator tooth 8 carries a stator winding 6. The individual stator windings 6 together form a winding arrangement. Depending on the number of magnetic poles to be formed by the stator windings 6, the individual stator windings 6 of the entire winding arrangement can be correspondingly electrically wired together.
[0089] During operation of the machine 1, the electrically energized stator windings 6 generate waste heat which has to be dissipated from the machine 1 in order to prevent overheating and associated damage or even destruction of the machine 1. Therefore, the stator windings 6 are cooled with the aid of a coolant K which is passed through the stator 2 and absorbs the waste heat generated by the stator windings 6 by means of heat transfer.
[0090] In order to pass the coolant K through the stator 2, the machine 1 comprises a coolant distributor chamber 4, into which a coolant K can be introduced via a coolant inlet 33. A coolant collector chamber 5 is arranged at a distance from the coolant distributor chamber 4 along the axial direction A. The coolant distributor chamber 4 communicates fluidically with the coolant collector chamber 5 by means of a plurality of cooling channels 10, only a single one of which is discernible in the illustration in FIG. 3. In a cross section perpendicular to the axial direction A, which cross section is not shown in the figures, the coolant distributor chamber 4 and the coolant collector chamber 5 can each have a ring-shaped geometry. Along the circumferential direction U, a plurality of cooling channels 10 are arranged at a distance from one another, which cooling channels extend in each case along the axial direction A from the ring-shaped coolant distributor chamber 4 to the ring-shaped coolant collector chamber 5. The coolant K introduced into the coolant distributor chamber 4 via the coolant inlet 33 can thus be distributed among the individual cooling channels 10. After flowing through the cooling channels 10 and absorbing heat from the stator windings 6, the coolant K is collected in the coolant collector chamber 5 and guided out of the machine 1 again via a coolant outlet 34 provided on the stator 2.
[0091] As revealed by the illustrations in FIGS. 3 and 4, interspaces 9 are formed between in each case two stator teeth 8 which are adjacent in the circumferential direction U. Said interspaces 9 are also known to a person skilled in the relevant art as so-called “stator slots” or “stator slits”, which extend along the axial direction A just like the stator teeth 8. An insulation body 100 composed of plastic 11 for receiving a stator winding 6 and a cooling channel 10 is inserted in each interspace 9. In this case, the insulation body 100 is arranged in the respective interspace 9 in such a way that the axial direction a of the insulation body 100 extends parallel to the axial direction A of the electrical machine 1 or of the stator 2.
[0092] Expediently, the insulation body 100 arranged in the respective interspace 9 extends along an entire interspace length I measured along the axial direction A of the machine 1 (in this respect, also cf. FIG. 3).
[0093] The illustration in FIG. 5 is explained below, which shows a detailed illustration of an interspace 9 embodied between two stator teeth 8 which are adjacent in the circumferential direction U—said stator teeth hereinafter also being referred to as stator teeth 8a, 8b. FIG. 5 shows the interspace 9 in a cross section perpendicular to the axial direction A.
[0094] In accordance with FIG. 5, the interspace 9 has an opening 52 radially on the inside, that is to say is formed such that it is open radially on the inside. The interspace 9 can have the geometry of a trapezium, in particular of a rectangle, in the cross section perpendicular to the axial direction A. The same applies to the geometry of the insulation body 100 in said cross section. Particularly expediently, the interspace 9 and the insulation body 100 have the same geometry or outer contour. In the example in FIG. 5, a first cooling channel 10 is arranged in the region of a radially inner end section 56a of the interspace 9 or of the stator slot 54, that is to say in the region of the opening 52. A further, second cooling channel 10 is arranged in the region of a radially outer end section 56b of the interspace 9, that is to say in the vicinity of the stator body 7 delimiting the interspace 9 radially on the outside.
[0095] As revealed by FIG. 5, the stator winding 6 arranged in the interspace 9 or in the body interior 104 comprises first and second conductor elements 60a, 60b. The first conductor elements 60a are arranged in the first winding zone 59a of the insulation body 100 and can be electrically connected to one another for the purpose of connection to a common first phase of an electrical power source (not shown). This electrical connection can be effected axially outside the interspace 9 or the stator slot 54. The second conductor elements 60b are arranged in the second winding zone 59b of the insulation body 100 and can be electrically connected to one another for the purpose of connection to a common second phase of the electrical power source. This electrical connection, too, can be effected axially outside the interspace 9 or the stator slot 54. The first conductor elements 60a are thus electrically insulated from the second conductor elements 60b by means of the phase insulation 108.
[0096] As illustrated by FIG. 5, the first and second conductor elements 60a, 60b are embodied in each case as winding bars 65a, 65b composed of an electrically conductive material and—on account of their barlike embodiment—also in mechanically stiff fashion. In the cross section perpendicular to the axial direction A, the winding bars 65a, 65b each have the geometry of a rectangle 66 having two narrow sides 67 and having two broad sides 68.
[0097] The first channel zone 107a having the first cooling channel 10 is arranged in the radially inner end section 56a of the interspace 9 with respect to the radial direction R. Accordingly, the second channel zone 107b having the second cooling channel 10 is arranged in the radially outer end section 56b of the interspace 9 with respect to the radial direction R. Along the radial direction R, therefore, the two winding zones 106a, 106b are arranged between the two channel zone 107a, 107b. Along the radial direction R from radially on the inside to radially on the outside, therefore, the first channel zone 107a having the first cooling channel 10 is followed by the first winding zone 106a having the first conductor elements 60a. The first winding zone 106a is followed by the second winding zone 106b having the second conductor elements 60b, said second winding zone being followed in turn by the second channel zone 107b having the second cooling channel 10 along the radial direction R.
[0098] As additionally revealed by FIG. 5, a first heat transfer layer 112a composed of plastic 11 can be arranged between the first and/or second conductor elements 60a, 60b of the stator winding 6 and the insulation body 100 in the cross section perpendicular to the axial direction A. As shown in FIG. 5, the first heat transfer layer 112a can also be arranged between two adjacent conductor elements 60a, 60b. Preferably, all first and second conductor elements 60a, 60b are surrounded by the plastic 11 in the cross section perpendicular to the axial direction A.
[0099] As an alternative or in addition to the first heat transfer layer 112a, a (second) heat transfer layer 112b composed of plastic 11 can be arranged between the respective cooling channel 10 and the insulation body 100 in the cross section perpendicular to the axial direction A.
[0100] As additionally revealed by FIG. 5, a spacer structure 113 is formed on the outer walls 101a, 101c, 101d of the insulation body 100, by means of which spacer structure the outer walls 101a, 101c, 101d can be arranged at a distance from the stator teeth 8a, 8b and/or the stator body 7 in the interspace 9. The spacer structure 113 is expediently formed by projections 114 arranged on an outer side of the respective outer wall 101b, 101c, 101d facing away from the body interior 104 of the insulation body 100. Particularly expediently, the projections 114 can be shaped integrally on the respective outer wall 101a, 101c, 101d. The spacer structure 113 is thus supported on the stator teeth 8a, 8b and on the stator body 7. In a simplified variant of the example, the spacer structure 113 can be dispensed with.
[0101] The gap 61 arising between the outer walls 101b, 101c, 101d and the stator teeth 8a, 8b and/or the stator body 7 can be filled with a third heat transfer layer 112c composed of plastic 11. This means that as an alternative or in addition to the first and/or second heat transfer layer 112a, 112b, a third heat transfer layer 112c composed of plastic 11 can be arranged between the insulation body 100 and the stator body 7 with the two adjacent stator teeth in the cross section perpendicular to the axial direction A.
[0102] As indicated in a dashed illustration in FIG. 5, a further cooling channel 10′ can be formed and arranged in the stator body 7, which is adjacent to the interspace 9 radially on the inside. Such an additional cooling channel 10′ can be realized in the form of a hole or a perforation.
[0103] FIG. 6 shows one variant of the example from FIG. 5. Only the differences between the two variants are explained below. In accordance with FIG. 6, a supporting structure 120 can be formed on those surface sections of the two stator teeth 8a, 8b and of the stator body 7 which face the interspace 9, on which supporting structure the outer walls 101b, 101c, 101d of the insulation body 100 can be supported. In a manner analogous to the spacer structure 113 of the insulation body 100, the supporting structure 120 can also be formed by projections 121 that protrude into the interspace 9 from the stator teeth 8a, 8b and/or from the stator body 7. The projections 121 of the supporting structure 120 can be shaped integrally on the two stator teeth 8a, 8b and/or on the stator body 7.
[0104] FIG. 7 shows a further variant of the example from FIG. 5. Only the differences between the two variants are explained below. In the example in FIG. 7, in the cross section perpendicular to the axial direction a, A, the insulation body 100 has the geometry of a trapezium having non-right-angled intermediate angles between respectively two adjacent outer walls 101a, 101b, 101c, 101d. Furthermore, a stator winding 6 having flexible conductor elements 60c is arranged in the sole winding zone 106a. In the example in FIG. 7, two cooling channels 10 are provided, wherein a first cooling channel 10 is arranged in the radially inner end section 56a of the interspace 9 and a second cooling channel 10 is arranged in the radially outer end section 56b of the interspace 9. Consequently, the first channel zone 107a of the insulation body 100 with the first cooling channel 10 is arranged in the region of the radially inner end section 56a. Accordingly, the second channel zone 107b with the second cooling channel 10 is arranged in the region of the radially outer end section 56b of the interspace 9. In the variant in FIG. 7, the insulation body 100 is formed such that it is open radially on the inside, that is to say toward the opening 52 of the interspace 9 or the stator slot 54. This means that the outer wall 101a of the insulation body 100 is omitted.
[0105] As revealed by FIG. 7, a separating wall 105b is provided only between the winding zone 106a and the second channel zone 107b. By contrast, such a separating wall is dispensed with between the winding zone 106a and the first channel zone 107a. In one variant, such a separating wall can be provided here as well. Accordingly, in a further variant, the outer wall 105c shown in FIG. 7 can be dispensed with. Further combination possibilities emerge which are evident to the person skilled in the relevant art directly from FIG. 7 and will therefore not be explained explicitly.
[0106] In the exemplary scenario, the plastic 11 of the first heat transfer layer 112a is formed by an electrically insulating first plastic material K1, the plastic 11 of the second heat transfer layer 112b is formed by an electrically insulating, second plastic material K2, and the plastic 11 of the third heat transfer layer 112c is formed by an electrically insulating, third plastic material K3. The plastic 11 of the electrical insulation body 100, in particular of the outer walls 101a-101d of the electrical insulation body 100, is formed by a likewise electrically insulating, fourth plastic material K4.
[0107] In the example in the figures, the fourth plastic material K4 of the insulation body 100 is a thermosetting plastic, whereas the first, second and third plastic materials K1, K2, K3 of the three heat transfer layers 112a, 112b, 112c are a thermoplastic. It goes without saying that, in variants in respect thereof, other assignments of thermoplastic and thermosetting plastic to the four plastic materials K1, K2, K3, K4 are also possible. In the exemplary scenario, the first, second and fourth plastic materials K1, K2, K4 each have a higher thermal conductivity than the third plastic material K3. An effective heat transfer from the stator winding 6 to the cooling channels 10 is ensured in this way. In the example in the figures, the four plastic materials K1, K2, K3, K4 are different materials. The thermal conductivity of all four plastic materials K1, K2, K3, K4 in this case is at least 0.5 W/m K, preferably at least 1 W/m K.
[0108] In the text that follows, reference is made once again to FIG. 3. In accordance with FIG. 1, the stator 2 having the stator body 7 and the stator teeth 8 is arranged axially between a first and a second end shield 25a, 25b.
[0109] As revealed by FIG. 3, a part of the coolant distributor chamber 4 is arranged in the first end shield 25a and a part of the coolant collector chamber 5 is arranged in the second end shield 25b. The coolant distributor chamber 4 and the coolant collector chamber 5 are thus in each case partly formed by a cavity 41a, 41b provided in the plastic composition 11. The first cavity 41a is supplemented here by a cavity 42a embodied in the first end shield 25a to form the coolant distributor chamber 4. Correspondingly, the second cavity 41b is supplemented by a cavity 42b embodied in the second end shield 25b to form the coolant collector chamber 5. In the embodiment variant explained above, the plastic 11 thus at least partly delimits the coolant distributor chamber 4 and the coolant collector chamber 5.
[0110] Furthermore, a coolant feed 35 can be embodied in the first end shield 25a and fluidically connects the coolant distributor chamber 4 to a coolant inlet 33 provided on the outside, in particular on the circumferential side as illustrated in FIG. 1, on the first end shield 25a. Correspondingly, a coolant discharge 36 can be embodied in the second end shield 25b and fluidically connects the coolant collector chamber 5 to a coolant outlet 34 provided on the outside, in particular on the circumferential side as illustrated in FIG. 1, on the end shield 25b. This enables an arrangement of the coolant distributor chamber 4 and/or of the coolant collector chamber 5 in each case radially on the outside on the first and/or second end section 14a, 14b of the relevant stator winding 6 and also in the extension of said end sections 14a, 14b along the axial direction A. The end sections 14a, 14b of the stator windings 6, said end sections being particularly subjected to thermal loading during operation of the machine 1, are cooled particularly effectively by means of this measure as well.
[0111] In accordance with FIG. 3, the plastic 11 can also be arranged on an outer circumferential side 30 of the stator body 7 and can thus form a plastic coating 11.1 on the outer circumferential side 30. The stator body 7 of the stator 2, said stator body typically being formed from electrically conductive stator plates, can thus be electrically insulated from the surroundings. The provision of a separate housing for accommodating the stator body 7 can thus be obviated.
[0112] FIGS. 1, 2, 4, 5, 6 and 7 additionally reveal that the insulation body 100 is formed such that it is insertable into the stator slot 54 of the stator 2 along the axial direction a. In this case, the insulation body 100 is formed such that it is insertable into the stator slot 54 in an accurately fitting way according to the examples shown. In this case, the insulation body 100 is formed in such a way that the insulation body 100 is insertable into the stator slot 54 in the manner of an interference fit or a transition fit. This presupposes, of course, corresponding coordination between the insulation body 100 and the stator slot 54 into which the insulation body 100 is insertable or is inserted in the examples in FIGS. 4, 5 and 6. The insulation body 100 is formed in a dimensionally stiff fashion. In this case, the insulation body 100 is expediently formed from a dimensionally stiff material. The insulation body 100 is reinforced by means of the separating wall 105a, 105b, 105c. This means that, in addition to subdividing the body interior 104, the separating wall 105a, 105b, 105c also fulfils the task of mechanically reinforcing the insulation body 100. The insulation body 100 is produced in non-forming fashion in accordance with the examples illustrated. It is furthermore evident that a cross section of the body interior 104 of the insulation body 100 defined perpendicular to the axial direction a is constant over an extent of the insulation body 100. In this case, the extent of the insulation body 100 runs along the axial direction a.
[0113] FIGS. 1, 2, 4, 5 and 6 furthermore show that a cross section of the insulation body 100 defined perpendicular to the axial direction a is both axially symmetrical and point-symmetrical. The outer walls 101a, 101b, 101c, 101d of the insulation body are connected to one another. In accordance with the examples shown, the outer walls 101a, 101b, 101c, 101d of the insulation body 100 are connected to one another without seams and/or joints.
