STATOR WITH PINS AND AN INTERNAL CONNECTION FOR AN ELECTRIC MACHINE

A stator for an electric machine has a plurality of pins, which are arranged on concentric circles at different distances from a stator center point in slots and each concentric circle forms a layer, wherein four pins in different layers are respectively connected to one another in series and form a winding, a first pin of the winding is located in a first slot in the 4n−3 layer, wherein n is a natural number, a second pin of the winding is located in a second slot in the 4n−2 layer, wherein the second slot is at a first radial distance from the first slot in a first circumferential direction of the stator, a third pin of the winding is located in the first slot in the 4n layer, a fourth pin of the winding is located in the second slot in the 4n−1 layer.

The invention relates to a stator with pins for an electric machine, in particular an electric motor.

PRIOR ART

Electric machines are generally known and are being increasingly used as electric motors for the driving of vehicles. An electric machine consists of a stator and a rotor.

The stator comprises a multiplicity of slots, in which the windings are guided. The windings may be formed from isolated copper rods in the form of what are referred to as pins. The rotor is located in the stator and is connected to a rotor shaft.

Such a pin motor, U-pin motor or hairpin motor is known, for example, from U.S. Pat. No. 9,136,738 B2.

Problem and Solution

The object of the present invention is to provide a stator having windings composed of pins, which is easy to manufacture.

According to the invention, a stator for an electric machine comprises a multiplicity of pins, which are arranged in slots on concentric circles that are at different distances from a stator center point and each concentric circle forms a layer, wherein four pins in different layers are respectively connected to one another in series and form a winding, a first pin of the winding is located in a first slot in the 4n−3 layer, wherein n is a natural number; a second pin of the winding is located in a second slot in the 4n−2 layer, wherein the second slot is at a first radial distance from the first slot in a first circumferential direction of the stator, a third pin of the winding is located in the first slot in the 4n layer, a fourth pin of the winding is located in the second slot in the 4n−1 layer.

A stator having the winding according to the invention can be produced easily and generates an efficient electromagnetic field. The types of connection produce an electrically conductive connection between the pins in the slots. The type of connection may be the welding of conductors onto the pins or the pins may already be in the form of a double pin, what is referred to as a U-pin, and thereby already produce a connection when inserted into the stator. The welding together of end portions of pins that are bent toward one another also constitutes a type of connection.

The layers can be numbered in increasing order from the outside to the inside in relation to the stator center point.

Preferably the stator can comprise a first and a second end face and for the first pin and the second pin to be connected to one another on the second end face by means of a first type of connection, for the second pin and the third pin to be connected to one another on the first end face by means of a second type of connection, for the third pin and the fourth pin to be connected to one another on the second end face by means of a third type of connection, wherein the first, second and third types of connection differ from one another.

The different types of connection make improved manufacture possible. Alternating the position of the types of connection on different end faces makes it possible to efficiently form a winding around the stator teeth lying between the slots.

Even types of connection on the same end face of the stator may differ by virtue of a pin foot being bent in different directions in relation to the stator interior or exterior.

A combination of the above-mentioned types of connection on different or the same end faces of the stator is also possible. The same type of connection on the same end faces and different types of connection on different end faces of the stator makes easy and quick manufacture possible. For example, on one end face the connection is produced by virtue of a type of pre-bent pins, what are referred to as double pins or else U-pins, and on another end face of the stator single pins or respective sides of the double pin are welded to one another. The weld points may lie at feet of the pins or double pins.

In one embodiment of the invention, the stator may comprise at least two windings and at least the fourth pin in the second slot may be connected to a fifth pin in the 4n−3 layer in a third slot by means of a fourth type of connection.

It is furthermore preferably possible for the stator to comprise a multiplicity of windings, which extend over the entire circumference of the stator and thereby form a part-coil.

This means that the windings have a symmetry which creates a uniform revolving field.

In a further embodiment, respective pins of two part-coils may be connected to one another by means of a fifth type of connection.

These pins may be what are referred to as end pins, since they mark the end of a part-coil. It is preferably possible for a second and a third end pin to be connected to one another by a fifth type of connection.

The fifth type of connection may be realized for example by a specially bent pin.

It is preferably possible for at least two part-coils to form a coil. An interconnection may be effected by way of two end pins, that is to say a fourth and an eighth end pin, for example. It is possible for the coils to be interconnected within one quarter of all of the slots of the stator, that is to say within one quarter of the stator circumference.

It is furthermore preferably possible for respective inputs of a pin of two coils to be connected to one another by means of a sixth type of connection.

The sixth type of connection may be produced by a conductor attached to the pins or by a conductive ring.

The two coils may be connected in parallel and may additionally be fed by the same phase. The parallel connection may be effected by connecting a first and a fifth or a fourth and an eighth end pin in pairs.

In a preferred embodiment of the invention, the part-coils may form six coils and six phases may be assigned to them in such a way that two coils, which are assigned to different phases, are respectively located in adjacent slots.

It is furthermore possible for two phases to respectively have an approximately identical current and voltage profile, and as a result for a six-phase inverter to control only a three-phase motor. This arrangement makes a current division of the switching elements in the inverter possible.

In one embodiment of the invention, respective inputs of a pin of two coils may be connected to one another by means of a sixth type of connection (66).

It is preferably possible for respective outputs of a pin of the two coils to be connected to one another and for the two coils as a result to be connected in parallel and in particular assigned to one phase.

Two coils of adjacent slots may thus be connected in parallel and fed by one phase, resulting in a stator having windings for a three-phase electric machine.

In one embodiment of the invention, it is possible for the second type of connection to comprise a first double pin, which is formed from the second pin and the third pin, wherein the first double pin has two inwardly bent pin feet with a respective weld point and bridges a first radial distance.

The double pin may be inserted into the stator from one end face and be welded to a further double pin on the other end face.

It is preferably possible for the fourth type of connection to comprise a second double pin, which is formed from the fourth pin and the fifth pin, wherein the second double pin has two outwardly bent pin feet with a respective weld point and bridges a first radial distance.

The first distance describes a number of slots to be bridged. The actual spatial distance to be bridged depends on the position of the pins in the layer, because the double pins connect different layers.

It is furthermore preferably possible for the fifth type of connection to comprise a third double pin, which is formed from a second end pin and a third end pin, wherein the third double pin has two pin feet which are bent anticlockwise, with a respective weld point and bridges a third radial distance.

The third radial distance may be at least one slot longer than the first radial distance.

In one embodiment, it is possible for a seventh type of connection to comprise a fourth double pin, which is formed from a sixth end pin and a seventh end pin, wherein the fourth double pin has two pin feet which are bent anticlockwise and bridges a second radial distance.

The second radial distance may be at least one slot shorter than the first radial distance.

Preferably, a single pin may comprise a first end pin or a fourth end pin or a fifth end pin or an eighth end pin, and have a pin foot which is bent clockwise and has a weld point.

In one embodiment, it is possible for the first type of connection to be formed by a welded connection between a first weld point at the pin foot of the first double pin or of the third double pin or of the fourth double pin and a second weld point at the pin foot of the second double pin or of the single pin.

Preferably, the third type of connection may be formed by a welded connection between a third weld point at the pin foot of the first double pin or of the single pin and a second weld point at the pin foot of the second double pin or of the third double pin or of the fourth double pin.

According to the invention, a vehicle comprises an electric machine with a stator according to one of the preferred embodiments.

FIG. 1shows a stator1having a multiplicity of slots5in which pins2,3are guided. The stator has a first end face7and a second end face9. On the first end face7, inputs81,87,101,107,111,117and outputs83,85,103,105,113,115of part-coils for connecting the pin to an energy source for the operation of the electric machine are shown. The inputs and outputs are respectively located in the outermost or innermost layer of the stator. Of course, a rotor is also necessary for the operation of an electric machine. For connection purposes, the pins lie close to one another and make short connection lines possible.

FIG. 2shows a stator1having slots51,52,53,54,55,56,57,58and pins21,22,23,24,26,27on four layers, only eight slots being illustrated. The pins are arranged in the slots. The pins lie next to one another in a slot; in the example ofFIG. 2, four pins lie next to one another in a slot. The four pins within one slot therefore lie on different concentric circles around the center point M of the stator, which circles thus form individual layers L1, L2, L3, L4. There is a distance71between two respective slots. This distance71is identical between all of the slots shown inFIG. 2.

FIG. 3shows the stator1fromFIG. 2. The pins are still arranged on concentric circles, that is to say layers, the concentric circles not being depicted for the sake of better illustration.FIG. 3illustrates which pins are connected to one another in series. A first pin21is located in a first slot51in the layer L1. This first pin51is connected to a second pin22in the slot52by means of a first type of connection61, illustrated as a dotted line. The second pin22is located in the layer L2. The second pin22is connected to a third pin23in the slot51by means of a second type of connection62, illustrated as a short-dashed line. The third pin23is located in turn in the first slot51, that is to say in the same slot as the first pin21. The third pin23, however, lies in the layer L4. Consequently, there is still space in the slot51for two further pins between the third pin23and the first pin21. The third pin23is connected to a fourth pin24via a third type of connection63, illustrated as a solid line. The fourth pin24lies in the same slot52as the second pin22. The fourth pin24lies in the layer L3directly next to the first pin21. Consequently, there is still space in the slot52for two further pins in layers L1and L4next to the two pins22,24. The serial connection of the first, second, third and fourth pins forms a first winding41.

The fourth pin24is connected to a fifth pin25in the layer L1in a third slot53via a fourth type of connection64, illustrated as a dashed line. With the fifth pin25, the above-described serial connection of the subsequent pins in the stator begins again, with the fifth pin25being similar to the first pin21but with the slot being offset by 90 degrees. The first pin21is connected to a pin27, which is similar to a fourth pin, via a fourth type of connection64. The pin27is in turn connected to a first end pin26via a third type of connection63, which first end pin has an input81, seeFIG. 12.

The serial connection of the fifth pin25to further pins in the slots53and54forms a second winding42. The first, second and third types of connection61,62,63between these pins are identical to the respective first, second and third types of connection61,62,63of the pins of the first winding41.

The two windings41,42are connected by the fourth type of connection64. The continuation of the serial connection forms the third winding43in the slots55,56. The windings41,42,43,44are respectively connected by means of the fourth type of connection64. The fourth type of connection64between the respective windings is therefore identical. It is also the case that the first, second and third types of connection61,62,63between the pins of the winding43are identical to the first, second and third types of connection61,62,63of the first and second windings41,42.

The fourth winding44constitutes a special feature and is formed at the beginning and at the end of the serial connection of the three other coils. The first pin21of the first winding41is connected to a pin28in slot58via the fourth type of connection64. This pin27is connected to the end pin26via a third type of connection63. After the circuit and the connection of the windings41,42,43, two further pins are connected according to the pattern shown inFIG. 3and the last pin28is configured as a second end pin, which thus completes the part-coil. The slots are at an identical distance71from one another.

FIG. 4shows the stator1fromFIG. 3and shows eight slots91,92,93,94,95,96,97,98, which are located in the direct vicinity of the slots ofFIG. 3.

The pins31,32,33,34,35are connected in the same way as the pins21,22,23,24,25ofFIG. 3. Even the type of connection is identical toFIG. 3and is made clear by the same reference signs. In the same way as described forFIG. 3, the windings45,46,47and48are formed and connected to one another clockwise by the fourth type of connection64. The first pin31is in turn a third end pin31.

The fourth pin in the slot98on the layer L1of the winding48is a fourth end pin38and has an output83for the connection of an energy source. The four windings45,46,47,48form a second part-coil.

FIG. 5shows a pin configuration through the first and the second part-coil fromFIGS. 3 and 4, which is illustrated by black squares. The same reference signs denote the same pins, slots and connections in the figures. The second end pin28of the winding44of the first part-coil in slot58, layer L2, and the third end pin31of the first winding45in slot91, layer L3, are connected by means of a fifth type of connection65. The two part-coils thus form a first coil with a first end pin26as input81and a fourth end pin38as output83after two radial circuits in different directions around the stator. It is therefore possible to see the end pins26,28,31,38which respectively mark the beginning and the end of a part-coil.

FIG. 6shows a pin configuration through the first and the second part-coil fromFIGS. 3 and 4, which are illustrated by black squares. The same reference signs denote the same pins, slots and connections in the figures. Furthermore, two further part-coils according to the principle ofFIGS. 3 and 4are indicated as black squares on a white background, but they are respectively offset by 5 slots in comparison with the first coil and respectively form a second and a third part-coil. These two part-coils are connected by means of a seventh type of connection67between a sixth end pin28ain slot98, layer L2, and a seventh end pin31ain slot57, layer L3, and form a second coil.

FIG. 6thus shows two parallel coils, each of which consists of two part-coils. The inputs and outputs of the coils are likewise shown. The input81of the first coil is located at the slot57and the output83at the slot98. The input87of the second coil is located at the slot91and the output85at the slot58. The inputs and outputs of the two coils are thus in adjacent slots on the outermost or innermost layer. The second radial distance73is for example one slot shorter than the first radial distance71. Furthermore, the third radial distance75is one slot longer than the first radial distance.

FIG. 7shows a pin configuration through a third and a fourth coil in the black squares with a white dot and the white squares with a black dot. This is produced by a winding pattern established inFIGS. 3, 4 and 5, which is offset clockwise by two slots in comparison with the pins and connections illustrated in the latter figures. The inputs101and outputs103of the third coil and inputs107and outputs105of the fourth coil are likewise shown. The inputs and outputs of the two coils are thus in adjacent slots on the outermost or innermost layer.

FIG. 8shows a pin configuration through a fifth and a sixth coil. This is produced by a winding pattern established inFIGS. 3, 4 and 5, which is offset clockwise by four slots in comparison with the pins and connections illustrated in the latter figures.

The inputs111and outputs113of the fifth coil and inputs117and outputs115of the sixth coil are likewise shown. The inputs and outputs of the two coils are thus in adjacent slots on the outermost or innermost layer.

FIG. 9shows a pin configuration through the six coils in the form of a combination ofFIGS. 6, 7 and 8. It is clear in particular from the position of the inputs81,87,101,107,111,117and outputs83,85,103,105,113,115that all of the inputs can be interconnected within one eighth of the stator. Furthermore, all of the outputs can also be interconnected within one eighth of the stator.

FIG. 10shows two coils201,202, each of which consists of two part-coils. The same reference signs establish the relationship with the other figures. The connection of the part-coils to the coil and the connection of the respective coil to an inverter, for example, can be seen inFIG. 10. Pin26of the first coil201constitutes a first end pin26and has an input81. A serial connection of the pins, filled in in black, by means of the solid-line arrows almost completes a single radial circuit around the stator and forms the first circuit, which comprises the first part-coil. The first end pin26is at the beginning of the first part-coil and the second end pin28is at the end.

The second part-coil is formed by connecting the pins, shown as horizontal dashes, by means of the dashed-line arrows. The part-coil begins with the third end pin31and ends with the fourth end pin38. The fourth end pin38is connected to an inverter, for example, by way of the output83. The fifth type of connection65is located between the second end pin28of the first part-coil and the third end pin31of the second part coil. The two end pins31,28and the fifth type of connection65are shown inFIG. 15. Both circuits of the first coil201take place in different directions, for example firstly clockwise and then anticlockwise.

The pin26aof the second coil202constitutes a fifth end pin26aand has an input87. A serial connection of the pins, filled in in black, by means of the solid-line arrows almost completes a single radial circuit around the stator and forms the first circuit, which comprises the first part-coil of the second coil202. The fifth end pin26ais at the beginning of the second part-coil and the sixth end pin28ais at the end.

The second part-coil is formed by connecting the pins, shown as horizontal dashes, by means of the dashed-line arrows. The part-coil begins with the seventh end pin31aand ends with the eighth end pin38a. The eighth end pin38ais connected to an inverter, for example, by way of the output85. The seventh type of connection67is located between the sixth end pin28aof the first part-coil and the seventh end pin38aof the second part-coil. The two end pins28a,38aand the seventh type of connection67are shown inFIG. 16.

The circulation directions of the two coils may be selected freely, but they are in the same circulation direction.

FIG. 11shows a single pin219or I-pin. The actual pin38,38awhich is arranged in the slot of the stator is located in the center. The reference signs are identical to the preceding figures. The pins are illustrated with the first end face7upward from the perspective of the stator center point. The output83,85,103,105,113,115is located at the top end. The single pin219is used on layer1for the fourth or eighth end pin38,38a. At the bottom end, the end pin has a pin foot61awith a second weld point223.

FIG. 12shows a single pin220or I-pin. The actual pin26,26awhich is arranged in the slot of the stator is located in the center. The reference signs are identical to the preceding figures. The pins are illustrated with the first end face7upward from the perspective of the stator center point. The single pin220is used on layer4for the first and fifth end pin26,26a. At the bottom end, the end pin has a pin foot63awith a third weld point225. The input81,87,101,107,111,117is located at the top end.

FIG. 13shows a first double pin211or U-pin, which establishes the type of connection62between a second pin22,32and a third pin23,33. The double pin may bridge the first distance71between the slots. At the bottom end, the double pin has two inwardly bent pin feet63a,61bwith a weld point225,221.

FIG. 14shows a second double pin213or U-pin, which establishes the type of connection64between a pin24,34,27and a pin21,25,35. The double pin may bridge the first distance71between the slots. At the bottom end, the double pin has two outwardly bent pin feet63b,61awith a weld point227,223.

The first distance71is identical only with respect to the number of slots to be bridged. The actual spatial distance to be bridged is different, because the double pins connect different layers.

FIG. 15shows a third double pin214or U-pin, which establishes the type of connection65between a second end pin28and a third end pin31. The double pin may bridge the third distance75, thus is one slot more than the distance71. At the bottom end, the double pin has two bent pin feet63b,61bwith a respective weld point227,221.

FIG. 16shows a fourth double pin215or U-pin, which establishes the type of connection67between a sixth end pin28aand a seventh end pin31a. The double pin may bridge the second distance73, thus is one slot less than the distance71. At the bottom end, the double pin has two bent pin feet61b,63bwith a respective weld point221,227.

The various single and double pins inFIGS. 11 to 16have similar pin feet. The connection61is formed by welding together the weld points221,223at the pin feet61a,61baccording to the winding pattern ofFIG. 10. The connection63is formed by welding together the weld points225,227at the pin feet63a,63baccording to the winding pattern ofFIG. 10.

The first type of connection61is thus formed via the pin feet61a,61band the weld points221and223. The third type of connection63is thus formed via the pin feet63a,63band the weld points225and227.

FIG. 17is a basic diagram of an exemplary embodiment of a vehicle403, for example a hybrid vehicle or an electric vehicle, comprising an electric machine401, in particular an electric motor, with an exemplary embodiment of the stator1for driving the vehicle403. The vehicle403may also comprise an inverter405, which supplies the electric machine401with an alternating current from a direct-current source.

LIST OF REFERENCE SIGNS