Coil for a compressor which can be electrically driven, and corresponding production method

Abstract

A method for producing a coil of a compressor (1) which can be electrically driven, a coil which is produced in accordance with this method, and a stator and a compressor which can be electrically driven. The production process for the coil includes the steps of: producing (100) a first winding (101) of the coil (12), producing (200) a second winding (102) of the coil (12), and compacting (300) the first winding (101) and the second winding (102) by virtue of an external action of force. A cross-sectional area (111, 112, 111, 112) of a wire of the first winding (101) and of the second winding (102) is deformed.

Claims

1. A method for producing a compressor (1) including an electric drive motor (7) having a stator with a coil (12) and having a rotor, said electric drive motor (7) having a predefined air gap between the stator and the rotor, the method comprising the steps of: producing (S100) a first winding (101) of the coil (12) from multiple loops of wire (111, 111), producing (S200) a second winding (102) of the coil (12) from multiple loops of wire (121, 121), compacting (S300) the first winding (101) and the second winding (102) by virtue of an external action of force, wherein a cross-sectional area of a wire (111, 111) of the first winding (101) and a cross-sectional area of a wire (121, 121) of the second winding (102) is deformed; wherein, for said compacting (S300) in a first direction, the windings (101, 102) of the coil (12) are arranged between substantially parallel surfaces (106, 107) of first and second tool parts (104, 105), wherein the surfaces (106, 107) of the tool parts (104, 105) have a curvature which serves to match the coil (12) to the predefined air gap between the stator and the rotor of the electric drive motor (7), and wherein compacting in the first direction occurs when the first tool part (104) is moved towards the second tool part (105), wherein the tool parts have first and second linear extension surfaces at the ends of the surfaces which have a curvature, wherein the windings (101, 102) of the coil (12) are compacted by a first die (108) moving in a second direction (P.sub.a) parallel to the first linear extension surfaces of the two tool parts (104, 105), wherein the windings (101, 102) of the coil (12) are compacted by a second die (109) in a third direction (P.sub.b) parallel to the second linear extension surfaces of the two tool parts (104, 105), whereby the compacted windings (101, 102) have a surface corresponding to the air gap between stator and rotor.

2. The method as claimed in claim 1, wherein, in a first step, the first winding (101) is compacted together with a first multiplicity of windings, and, in a second step, the second winding (102) is compacted together with a second multiplicity of windings to form a coil (12).

3. The method as claimed in claim 2, wherein volume of the coil (12) is reduced by 5% to 30%.

4. The method as claimed in claim 2, wherein volume of the coil (12) is reduced by 10% to 20%.

5. The method as claimed in claim 1, wherein the coil is compacted in a magnetically active section (I, II, III, IV), and wherein a winding head (25a, 25b) of the coil is also compacted, after all of the windings (101, 102) of the coil are produced.

6. A coil for an electrically driven compressor (1) obtained by the method as claimed in claim 1.

7. A stator for an electrical drive of a compressor (1), comprising a coil as claimed in claim 6.

8. The stator as claimed in claim 7, comprising three coils which are arranged in a delta circuit by adjacent electrical connections of two coils being combined in each case for the purpose of allowing an external electrical connection to make contact with said electrical connections.

9. The stator as claimed in claim 7, the coils of said stator being fixed relative to one another by means of a cured fluid.

10. A compressor (1) for an internal combustion engine, which compressor can be electrically driven and comprises an electrical drive having a stator as claimed in claim 7.

11. The stator as claimed in claim 7, the coils of said stator being fixed relative to one another by means of a cured insulating enamel or adhesive.

12. The method as claimed in claim 1, wherein each wire comprises a plurality of copper strands encased in insulation.

13. The method as claimed in claim 1, wherein the second winding is compacted subsequent to the first winding.

14. The method as claimed in claim 1, wherein the first and second windings are compacted together.

15. The method as claimed in claim 1, wherein, in a first step, a first multiplicity of windings is compacted together, and, in a second step, a second multiplicity of windings is compacted together to form a coil.

16. The method as claimed in claim 1, wherein the curvature of the surfaces (106, 107) of the tool parts (104, 105) extends over 90.

17. The method as claimed in claim 1, wherein the curvature of the surfaces (106, 107) of the tool parts (104, 105) extends over 120.

18. The method as claimed in claim 1, wherein the curvature of the surfaces (106, 107) of the tool parts (104, 105) extends over 180.

Description

(1) Further details, advantages and features of the present invention emerge from the following description of exemplary embodiments with reference to the drawing, in which:

(2) FIG. 1 is a schematically slightly simplified sectional illustration through a first embodiment of a charging apparatus according to the invention;

(3) FIG. 2 is a schematically highly simplified illustration of an internal combustion engine which can be provided with a charging apparatus according to the invention;

(4) FIG. 3 is a schematic illustration of fully twisted wires of a stator winding according to the prior art;

(5) FIG. 4 is a schematic illustration of wires of a stator winding, which wires are twisted only in the winding head, according to one exemplary embodiment of the present invention;

(6) FIG. 5 is a sectional illustration of an exemplary embodiment of a tool which can be used for compaction purposes;

(7) FIG. 6 shows the tool which is illustrated in FIG. 5 after it is opened;

(8) FIG. 7 shows a perspective view of the tool which is illustrated in FIGS. 5 and 6;

(9) FIG. 8 shows basic sketches for illustrating a change in cross section which takes place due to the compaction according to the invention;

(10) FIG. 9 is a perspective illustration of a coil which is compacted in the magnetically active region; and

(11) FIG. 10 shows a flowchart which illustrates method steps of an exemplary embodiment of a production method according to the invention.

(12) FIG. 1 shows an embodiment of a charging apparatus comprising an electrically driven compressor 1. The compressor 1 has a compressor housing 2 in which a compressor wheel 3 is arranged. The compressor wheel 3 is mounted on one end 4 of a rotor shaft 5.

(13) As is also illustrated in FIG. 1, the compressor housing 2 has a compressor housing rear wall 6 which is in the form of a compressor housing cover in the illustrated embodiment. The compressor housing rear wall 6 is arranged behind the compressor wheel 3 and fixed to the compressor housing 2 and closes said compressor housing in this way.

(14) In this case, the compressor housing rear wall 6 is provided with a cooling jacket 10, preferably for cooling water.

(15) The compressor 1 also has an electric motor 7. The electric motor 7 comprises a shaft 8 which is connected to a rotor shaft 5. In the illustrated embodiment, the shaft 8 and the rotor shaft 5 are designed as an integral component, as is shown in detail in FIG. 1. In this case, the shaft 8 is in the form of a shaft stub which has a smaller outside diameter than the rotor shaft 5 and on which a bearing 16 is arranged. The end 4 of the rotor shaft 5 is likewise of reduced diameter in relation to the rotor shaft 5 and is fitted with a second bearing 17. As shown in FIG. 1, the bearing 17 is supported against a bearing section of a stator housing 13, whereas the bearing 16 is supported, by way of its outer ring, in a recess of the compressor housing rear wall 6.

(16) A magnet 11 is also provided on the rotor shaft 5, said magnet interacting with a stator winding 12 which surrounds said magnet on the outside. The structure of the stator winding 12 according to the invention is discussed in greater detail in connection with FIGS. 3, 4, 8 and 9. The stator winding 12 is surrounded by an iron ring 18 in order to improve the magnetic flux guidance. A cooling jacket 10 which carries liquid is also provided in order to draw heat from the stator winding 12.

(17) The embodiment of the compressor 1 according to FIG. 1 also has a dirt-protection cover 14 which is mounted on the stator housing 13 or on the compressor housing rear wall 6 and in which electronics components 15 of a power electronics circuit 9 or electronics printed circuit board 9 are arranged. The power electronics circuit 9 can comprise all of the required components for fulfilling the function of an electronic commutator. Said power electronics circuit is, in particular, a control circuit comprising transistors or so-called MOSFETs. The power electronics circuit 9 can also comprise sensors, in particular Hall sensors. The electronics components 15 comprise, in particular, a capacitor, amongst others.

(18) As illustrated in FIG. 1, the power electronics circuit 9 is arranged between the compressor housing rear wall 6 and the electric motor 7 or the dirt-protection cover 14. To this end, the power electronics circuit 9 can be firmly clamped, for example, between the dirt-protection cover 14 and the compressor housing rear wall 6, or else mounted, for example fixedly adhesively bonded, on one of the two parts.

(19) This arrangement results in the advantage that the power electronics circuit 9 is arranged adjacent to the cooling jacket 10, this considerably improving the cooling effect of said cooling jacket with respect to the power electronics circuit 9.

(20) A thermally conductive paste can be provided between the power electronics circuit 9 and the cooling jacket 10 or the compressor housing rear wall 6 in which the cooling jacket 10 is arranged.

(21) The compressor housing rear wall 6 could also be formed by an end wall of the stator housing 13, in which end wall the bearing 17 would then be arranged. In this embodiment, the stator housing 13 likewise has an inner cooling arrangement and therefore a cooling jacket 10, wherein, in this embodiment too, the power electronics circuit 9 is arranged between the compressor housing rear wall 6 and the electric motor 7 or its stator housing 13, and therefore enjoys the same advantages of a compact construction and improved cooling of the components.

(22) FIG. 2 is a schematically highly simplified illustration of a combustion engine 26, for example in the form of a (diesel or petrol) internal combustion engine. The internal combustion engine 26 has an intake line 27 in which the compressor 1 of the charging apparatus 20 is arranged, said compressor being driven by the electric motor 7. A charge air cooler 28, followed by a throttle 29, can be arranged downstream of the compressor 1 in the intake line 27. The compressed air, which is symbolized by the arrow CA, from the compressor 1 is supplied to an intake manifold 30, and the cylinders of the combustion engine 26 are supplied with the compressed air from said intake manifold.

(23) The exhaust gas EG is supplied to an exhaust gas line 32 via an exhaust gas manifold 31.

(24) In the particularly preferred embodiment which is illustrated in FIG. 2, the internal combustion engine 26 is also provided with an exhaust gas return line 33 in which an exhaust gas cooler 34 and a valve 35 are arranged. However, said exhaust gas return line 33, together with its components 34 and 35, is not mandatory, but rather constitutes merely a particularly preferred embodiment. A variant, which is not illustrated, of the arrangement which is illustrated in FIG. 2 differs by virtue of the arrangement of the components compressor 1, electric motor 7 and charging apparatus 20 further downstream. By way of example, the assembly comprising the abovementioned components can be shifted in such a way that the compressor 1 is connected behind the throttle 29 and the valve 35 in front of the intake manifold 30.

(25) FIG. 3 shows a first conductor 22 and a second conductor 23 of a line 21 for a coil of a stator. The conductors 22, 23 of a wire can be electrically insulated from one another in order to avoid circulating currents. The first conductor 22 and the second conductor 23 are twisted in relation to one another both in successive magnetically active sections I, II, III and IV and also in winding head regions 25a, 25b which are situated between said sections. In other words, the conductors 22, 23 have a first degree of twisting in the respective magnetically active section I, II, III and IV which is identical to the second degree of twisting in the winding head region 25a, 25b. Although the illustrated twisting can prevent compensation currents (circulating currents) between the conductors 22, 23, firstly, additional volume is taken up in the magnetically active sections I, II, III and IV and, secondly, a mechanical strength of the line 21, which may be obstructive during shaping of the stator winding 12 and can prevent a compact design of the coil, is already produced before the stator winding 12 is shaped.

(26) FIG. 4 shows a stator winding 12 of alternative configuration. It can be seen in said figure that that the conductors 22, 23 of the line 21 are twisted in relation to one another in the winding head region 25a, 25b, as illustrated in FIG. 2, while they run parallel next to another in a non-twisted manner in the magnetically active sections I, II, III and IV. In the process, said conductors change the relative order in relation to one another in each case in successive magnetically active sections I, II, III and IV. While the first conductor 22 is arranged to the left (in the figure) and at the front in the circumferential direction U in the first magnetically active section I, said first conductor is arranged behind the second conductor 23 with respect to the circumferential direction U in the second magnetically active section II. The change in the order between the conductors 22, 23 changes continuously in the circumferential direction U. Owing to the non-twisted design of the conductors 22, 23 in the magnetically active sections I, II, III, IV, a compact design of the stator is possible and application of the method according to the invention is accompanied with a reduced risk of damage to electrical insulations of the conductors 22, 23.

(27) FIG. 5 shows a sectioned side view through a tool of an exemplary embodiment of a production method according to the invention. Wires 101, 102, 103 of a coil 12 are inserted into a lower tool part 105 as stator winding. The wires 101, 102, 103 are compacted in the vertical direction by means of an upper tool part 104 which is guided relative to the lower tool part 105 by means of a guide 113. In other words, the wires 101, 102, 103 are clamped between substantially parallel surfaces 106, 107. A first die 108 and a second die 109 can be pushed between the tool parts 104, 105 in the direction of two arrows P.sub.a, P.sub.b and compact the wires 101, 102, 103, wherein the cross-sectional areas of said wires are deformed, as is illustrated in FIG. 8.

(28) In FIG. 6, the upper tool part 104 has been raised along the guide 113 in order to be able to remove the coil 12 after compaction is complete.

(29) FIG. 7 shows a perspective view of the production apparatus which is illustrated in FIGS. 5 and 6. It can be seen in said figure that the upper tool part 104 is provided with openings through which the first die 108 and the second die 109 can penetrate as far as into the gap, which is shown in FIG. 5, between the surfaces 106 and 107. A third die 134, which is pushed between the upper tool part 104 and the lower tool part 105 in the axial direction, for compaction of the winding heads is additionally illustrated.

(30) FIG. 8a shows two wires 101, 102, the copper cores 111, 121 of which have cross-sectional areas which are substantially in the form of a circular disk. The wires 101, 102 are surrounded by an insulation 133 which accordingly has cross-sectional areas which are substantially in the form of a ring. The arrows P.sub.1, P.sub.2, P.sub.3, P.sub.4 illustrate an action of force during the course of a compaction process according to the invention of the wires 101, 102.

(31) FIG. 8b shows the result of the compaction process indicated in FIG. 8a. The copper cores 111, 121 have acquired a substantially rectangular cross-sectional shape. The insulation 133 of the wires 101, 102 has also adapted to the rectangular shape. It can be seen that the volume V, which is indicated in FIG. 8a, of the outside dimensions of the wires 101, 102 has reduced to the volume V which is illustrated in FIG. 8b. There are substantially no longer pockets of air, as a result of which the power density is increased.

(32) FIG. 9 shows a perspective view of an alternative exemplary embodiment of a coil 12 which is manufactured according to the invention. The coil 12 has compacted wires 101, 102, 103 in its magnetically active sections I, II, while the winding heads 25a, 25b substantially have their (uncompacted) original configuration. Said illustration also shows the potential for a reduction in volume by virtue of the compaction process according to the invention.

(33) FIG. 10 shows a flowchart which illustrates the steps of an exemplary embodiment of a production method according to the invention. A first winding of a coil 12 is produced in step S100. A second winding of the coil 12 is produced in step S200. Then, (for example axial and tangential and radial) compaction of the first winding and of the second winding is performed in step S300. In step S400, the compacted coil is arranged in a tool for assembling a stator according to the invention.

(34) In other words, a tool for shaping the stator is equipped with several coils which are manufactured according to the invention. Then, in step S500, the stator is manufactured by the inserted coils 12 being compacted once again and being fixed relative to one another by means of stove enamel. The compaction of each coil (independently of the other coils) is also fixed in this way.

(35) In addition to the above written description of the invention, reference is hereby explicitly made, for additional disclosure thereof, to the diagrammatic illustration of the invention in FIGS. 1 to 10.

LIST OF REFERENCE SIGNS

(36) 1 Compressor 2 Compressor housing 3 Compressor wheel 4 End 5 Rotor shaft 6 Compressor housing rear wall 7 Electric motor, in particular brushless DC motor 8 Shaft 9 Power electronics circuit/electronics printed circuit board 10 Cooling jacket 11 Magnet 12 Stator winding, coil 13 Stator housing 14 Dirt-protection cover 15 Electronics components 16, 17 Bearings 18 Iron ring 19 Gap 20 Charging apparatus 21 Line 22 to 24 Conductor 25a, 25b Winding head region 26 Internal combustion engine 27 Intake line 28 Charge air cooler 29 Throttle 30 Intake manifold 31 Exhaust gas manifold 32 Exhaust gas line 33 Exhaust gas return line 34 Exhaust gas cooler 35 Valve 36 Compressor wheel rear side 101, 102, 103 Wires 104, 105 Tool parts 106, 107 Surfaces of the tool parts 108, 109 Dies 111 Copper core 113 Guide 121 Copper core 133 Insulation 134 Die S100 to S500 Method steps V Volume I to IV Magnetically active section