CH716105A1 - Stator coil with stepped head. - Google Patents

Abstract

The invention relates to a stator (10) for a slotless electric motor (1), the slotless electric motor (1) comprising the stator (10) and a rotor (50) arranged to rotate about an axis of rotation ( X), the stator (10) comprising at least a first layer or stratum made with a plurality of first coils (11, 12, 13) forming an armature (30) having a generally tubular shape arranged to receive the rotor (50), the frame (30) comprising at least one row of first coils (11, 12, 13), characterized in that each of the first coils (11, 12, 13): is formed with a wire having a rectangular cross section, has two coil heads (11c, 11d) with: a first part positioned at a first radial distance from the axis of rotation (X), a second part positioned at a second radial distance from the axis of rotation (X), different of the first radial distance.

Description

The present invention relates to the field of electric motors, in particular slotless motors and their stator.

[0002] Document JP05975638B2 describes a slotless motor with a coil or winding of flat wire.

The disadvantage of the stator and the electric motor of the document of the prior art lies in the fact that the coil or winding, and in particular the head, is not compact enough and does not have a high fill factor , so that the performance of stator and brushless motor is not high.

[0004] Document US20130082560A1 describes different flat wire coils forming a stator.

[0005] The disadvantage of the stator of this prior art document lies in the fact that the coils have different shapes and do not allow a compact design, which makes the manufacture more complex and reduces performance.

[0006] The object of the present invention is to deal with the drawbacks of the prior art mentioned above.

[0007] For this purpose, a first aspect of the invention is to provide a stator for an electric motor without a slot, the slitless electric motor comprising the stator and a rotor arranged to rotate about an axis of rotation, the stator comprising at least a first layer or stratum produced with a plurality of first coils forming an armature having a generally tubular shape arranged to receive the rotor, characterized in that each of the first coils: <tb> <SEP> is formed with a wire having a rectangular cross section, has two coil heads with: <tb><SEP> <SEP> a first part of each coil head which is positioned at a first radial distance from the axis of rotation, <tb><SEP> <SEP> a second part of each coil head which is positioned at a second radial distance from the axis of rotation, different from the first radial distance.

[0008] This makes it possible to provide a stator with a higher coil fill factor in the active part of the coils (between the heads) and a compact design, in particular with compact heads or the ends of coils, in order to increase the performance of the stator. The windings or coils are made of a suitable material, such as copper or the like. The stator of the present invention thus exhibits an increased volume of copper. The first part and the second part are arranged to be nested with one another in a general circular or tubular path, so that the fill factor and the compactness are improved and the performance of the stator improved. This also allows for a high coil fill factor in the form of a high part distribution of the coils in front of the rotor and the rotor magnets. That is, there is a high concentration of the coil part in front of the magnetically active part of the rotor, and this improves the performance of the motor.

[0009] In other words, each first coil has two active parts (the parts between the heads, where the (flat) wire is parallel to the axis of rotation), which are positioned at the same radial distance from the axis of rotation than the active parts of the adjacent first coil, while each of the active parts of said first coil is arranged between two active parts of another first coil. This arrangement is possible when the second part of each head of a first coil is above (or below) the first part of each head of the adjacent first coil.

[0010] The generally tubular shape has an axis of rotation which is designed to be identical to the axis of rotation of the rotor when the motor is assembled. The first coils are placed to form a first layer or stratum of first coils, i.e. the coils form a row on a tubular path. Several layers or rows may be provided, being arranged concentrically around the axis of rotation. The wire has a rectangular cross section, that is, a flat wire. The ends or coil heads form the heads of the coils, at each axial end of the tubular shape.

[0011] Advantageously, each coil end of each of the first coils has a radial thickness, and in which the first radial distance differs from the second radial distance at least by the radial thickness.

[0012] Advantageously, in the coil heads, the cross section of the flat wire is substantially parallel to the axis of rotation.

This makes it possible to have a high fill factor, a high compactness of the coils and in particular a high compactness of the ends or heads of the coil.

[0014] Advantageously, the second part of each of the first coils is arranged above the first part of the adjacent identical coil.

[0015] Advantageously, the second part of each of the first coils is arranged below the first part of the adjacent identical coil.

[0016] Advantageously, at least one of the second parts of the first coils is arranged above the first part of the adjacent coil, and in which at least one of the second parts of the first coils is arranged above- below the first part of the adjacent coil.

[0017] Advantageously, the first coils are identical.

This makes it possible to have a nesting or overlap between identical adjacent coils in the reinforcement, so that the deposition factor, the compactness and the performance are improved. In addition, this makes it possible to facilitate the manufacture of the stator with identical coils, and to create a free space for any other part of the motor in the area of the ends or the heads.

Advantageously, the first coils are surrounded by a second row of second coils.

[0020] Advantageously, the second coils have the same shape as the first coils, except for a greater radial distance from the axis of rotation.

This makes it possible to have a high fill factor, a high compactness of the stator, while using different rows of coils. In particular, this makes it possible to have the first coils made with a first material, and the second coils made with a second material, different or identical.

[0022] Advantageously, the motor has an air gap radius and the smallest among the first radial distance and the second radial distance is greater than the air gap radius.

[0023] Advantageously, the motor has an air gap radius, and the largest among the first radial distance and the second radial distance is less than the air gap radius.

[0024] This makes it possible to provide a stator with free space for other parts of the engine, and an improved design with a high fill factor, high compactness and thus with high performance. In addition, this facilitates the manufacture of the stator and the rotor, when said distance is less than the air gap radius; while this facilitates manufacturing with a two-part electric motor tube of the motor when said distance is greater than the air gap radius.

[0025] A second aspect of the present invention is a slotless electric motor comprising a rotor and the stator according to the first aspect.

[0026] This makes it possible to provide an engine with a high fill factor, high compactness and high performance, with an improved volume of copper and an improved copper ratio.

A third aspect is a method for assembling a stator according to the first aspect, in which the method comprises at least: <tb> <SEP> a step to nest one of the first coils with an adjacent coil of the first coils.

This makes it possible to facilitate assembly of the stator and to provide a method for assembling a stator with an improved fill factor, high compactness and high performance.

A fourth aspect is a method for assembling a brushless motor according to the second aspect, wherein the method comprises at least: <tb> <SEP> a step to nest one of the first coils with an adjacent coil of the first coils.

This makes it possible to facilitate the assembly of the parts of the motor in order to obtain a brushless motor with a high fill factor, high compactness, high coil or copper volume, with improved performance.

Other characteristics and advantages of the present invention will emerge more clearly from the following detailed description of particular non-limiting examples of the invention, illustrated by the accompanying drawings, in which:

[0032] - Figure 1 shows an engine according to the present invention,

- Figure 2 shows one of a plurality of first coils of a stator according to the present invention;

[0034] FIG. 3 represents another embodiment of the plurality of first coils of the stator according to the present invention;

- Figure 4 shows the first layer of the plurality of first coils forming an armature, according to the first embodiment.

[0036] Figure 1 shows an engine according to the present invention.

The motor 1 comprises a rotor 50 and a stator 10.

[0038] The rotor 50 comprises a plurality of magnets 54 mounted on a support element 57, said support element 57 being mounted on a shaft 51 and being made of steel. The plurality of magnets 54, for example four magnets 54, form an outer surface of the rotor 50, so that the magnets 54 face directly the stator 10 of the electric motor 1, forming an air gap 70 between the magnets 54 and the stator 10 The external surface is considered to be cylindrical in the example given.

The rotor 50 can also include a one-piece shaft, that is to say that the plurality of magnets 54 can be installed on the support element 57 of Figure 1 or on the one-piece shaft without a control element. support 57.

The rotor 50 further comprises two rings 53 force-mounted on said shaft 51 to be fixed on said shaft 53 made of steel. The two rings 53 are mounted at each longitudinal end of the shaft 51 and at the level of the longitudinal end of the magnets 54 mounted on the shaft 51. Each ring 53 is made of metal such as steel, mild steel. or brass.

The stator 10 comprises at least a first layer or stratum of a plurality of first coils 11, 12, 13 forming a frame 30 having a generally tubular shape arranged to receive the rotor 50.

The frame 30 comprises at least one row of first coils 11, 12, 13. Both the frame 30 and the rotor 50 have an axis of rotation X and this axis X is designed to be the same when the rotor 50 is assembled in the frame 30, in order to form the motor 1. The frame 30 is also shown in FIG. 4.

The stator 10 further comprises a stack of sheets 71 mounted on the first plurality of first coils 11, 12, 13 and axially held by two plastic or steel rings.

[0044] The motor 1 further comprises an electric motor tube 2, surrounding the stack of sheets 71.

The electric motor 1 further comprises a set of bearings, such as ball bearings 52, made of aluminum or steel and mounted at each of its ends and a spring 55 arranged to preload the ball bearing 52 .

The electric motor 1 further comprises a set of encoder wires connected to an encoder or to an incremental encoder, which may be a Hall effect sensor, for example, arranged to monitor the speed of rotation or the rotary displacement of the rotor 50, using the magnet and the magnet support mounted on the ring 53 or directly on the shaft 51.

[0047] Figure 2 shows one of a plurality of first rings of a stator according to the present invention.

The first 11 of the plurality of first coils 11, 12, 13 is shown in Figure 2. The numerical designation of the first 11, second 12 and third 13 of the plurality of first coils 11, 12, 13 is performed for clarity and is classic.

The first 11 of the plurality of first coils 11, 12, 13 comprises a wire 11a having a rectangular cross section, and has two ends or heads of coils 11c, 11d, each end or head of coils 11c, 11d having first parts 111, 114 positioned at a first radial distance from the axis of rotation X, and the second parts 112, 115 positioned at a second radial distance from the axis of rotation X, different from the first radial distance.

The first parts 111, 114 and the second parts 112, 115 are separated by the stepped parts 113, 116 respectively. The first radial distance is less than the second radial distance.

One end of coil 11d is equipped with electrical wire connections 117a for connecting coil 11 to a current supply supplying electricity to electric motor 1. The other end of coil 11c is not equipped with connections of wire 117a.

The first coil 11 comprises two long parts 119a, 119b along the X direction and curved along a radial direction.

The first long part 119a is on the side of the first parts 111, 114, while the second long part 119b is on the side of the second parts.

In other words, the frame 30 has the general tubular shape, and each of the plurality of coils 11, 12, 13 is a part of the generally tubular part, and thus has an elongated shape along the X direction and a curved or rounded or circular shape in the radial direction.

The first long part 119a is formed at the first radial distance from the axis of rotation X which is the same as the first parts 111, 114; the second long part 119b is formed at the first radial distance from the axis of rotation X which is the same as the first parts 111, 114.

The second long part 119b is separated from the second parts 112, 115 by stepped parts 112c, 115d respectively.

The long parts 119a, 119b are placed at the same radial distance in order to have a constant air gap 70 when the rotor 50 and the stator 10 are assembled, and improve the performance of the motor 1.

In a preferred embodiment, each coil end 11c, 11d of the first coil 11 has a radial thickness, and the first radial distance differs from the second radial distance at least by the radial thickness.

In other words, the stepped parts 113, 116, 112c, 115d have a radial dimension equal to the radial thickness of the first coil 11 and with the usual mechanical tolerances to be taken into account.

Each of the first coils 11, 12, 13 is formed with the same design as the first coil 11, that is to say with a wire having a rectangular cross section 11a and has two coil heads 11c, 11d with first parts 111, 114 positioned at a first radial distance from the axis of rotation X, and second parts 112, 115 positioned at a second radial distance from the axis of rotation X, different from the first radial distance.

When assembled, the second coil 12 is nested in the first coil 11 in a radial direction, at the coil heads 11c, 11d.

In other words, when assembled, the first parts of the coil heads of the second coil 12 are nested in the second parts 112, 115 of the coil heads 11c, 11d of the first coil 11. The long parts of the second coil 12 connect the second long part 119b of the first coil 11, in order to have a large distribution of the long parts of the coils around the first radial distance, and thus to increase the coil filling factor.

The plurality of coils 11, 12, 13 is composed of copper or any other metallic material or material suitable for conducting electricity.

[0064] In the embodiment of Figures 1, 2 and 4, the coil heads 11c, 11d are positioned on a diameter which is greater than the diameter of the location of the air gap 70, while in the embodiment In Figure 3, the coil heads 21c, 21d are positioned on a diameter which is smaller than the diameter of the location of the air gap 70.

[0065] FIG. 3 represents another embodiment of the plurality of first coils of the stator according to the present invention.

The first 21 of the plurality of first coils 21, 22, 23 is shown in Figure 3. The numerical designation of the first 21, the second 22 and the third 23 of the plurality of first coils 21, 22, 23 is done for clarity and is classic.

The first 21 of the plurality of first coils 21, 22, 23 comprises a wire 21a having a rectangular cross section, and has two coil heads 21c, 21d, each coil head 21c, 21d having a first part 211, 214 positioned at a first radial distance from the axis of rotation X, and a second part 212, 215 positioned at a second radial distance from the axis of rotation X, different from the first radial distance.

The first parts 211, 214 and the second parts 212, 215 are separated by stepped parts 213, 216. The first radial distance is less than the second radial distance.

One end of coil 21d is equipped with electrical wire connections for connecting the coil 21 to a current supply supplying electricity to the electric motor 1. The other end of coil 21c is not equipped with connections of wire.

The first coil 21 comprises two long parts 219a, 219b along the X direction and curved along a radial direction.

In other words, the frame 30 has the generally tubular shape and each of the plurality of coils 21, 22, 23 is a part of the generally tubular part and thus has an elongated shape along the X direction. and a curved or rounded or circular shape in the radial direction.

The first long part 219a is formed at the second radial distance from the axis of rotation X which is the same as the second parts 212, 215; the second long part 219b is formed at the second radial distance from the axis of rotation X which is the same as the second parts 212, 215.

The first long part 219a is separated from the coil end 211, 214 by stepped parts 211c, 214d.

The long parts 219a, 219b are placed at the same radial distance in order to have a constant air gap 70 when the rotor 50 and the stator 10 are assembled, and to improve the performance of the motor.

In a preferred embodiment, each coil end 21c, 21d of the first coil 21 has a radial thickness, and the first radial distance differs from the second radial distance at least by the radial thickness. In other words, the stepped parts 213, 216, 211c, 214d have a radial dimension equal to the radial thickness of the first coil 11.

Each of the first coils 21, 22, 23 is formed with the same design as the first coil 21, that is to say with a wire having a rectangular cross section 21a, and has two ends or coil heads 21c , 21d with a first part 211, 214 positioned at a first radial distance from the axis of rotation X and a second part 212, 215 positioned at a second radial distance from the axis of rotation X, different from the first radial distance.

When assembled, the second coil 22 is nested in the first coil 21 in a radial direction, at the coil heads 21c, 21d.

In other words, when they are assembled, the first parts of the ends or coil heads of the second coil 22 are nested in the second parts 212, 215 of the ends or coil heads 21c, 21d of the first coil 21.

The long part of the second coil 22 compensates for the second long part 219b of the first coil 21, in order to have a large distribution of the long parts around the first radial distance, thus providing a high filling factor.

FIG. 4 represents the first layer of the plurality of first coils forming an armature.

In Figure 4, the first coils 11, 12, 13 of the first embodiment are assembled and nested to form the frame 30.

The frame 30 has a generally tubular shape, with an axis of rotation X.

[0083] In Figure 4, wire connections 117a are omitted, while the numerical designation of a single coil end is shown for clarity.

The first coil 11 comprises the coil heads 11d, with the first part 114, the second part 115 and the long part 119a, 119b. The second part 115 of the first coil 11 is radially nested with the first part of the coil 12.

The second part of the second coil 12 is nested in the first part of the third coil 13. To complete the armature 30 over 360 degrees, it is necessary to place six coils 11, 12, 13, with such a nesting .

[0086] In other words, the first parts of an "N" coil are arranged below the second parts of the adjacent "N-1" coil; while the second parts of the "N" coil are arranged above the first parts of the adjacent "N + 1" coil. The numerical designation "N-1", "N" and "N + 1" is considered to be clockwise. With such successive radial nesting, the frame 30 is formed with the generally tubular shape, and the high fill factor is achieved.

The air gap 70 is formed between the internal surface of the long parts 119a, 119b of the whole set of coils and the external surface of the magnets 54 of the rotor 50.

It is of course clear that improvements and / or modifications obvious to a person skilled in the art can be implemented, while being within the scope of the invention as defined by the appended claims.

Claims (10)

1. Stator (10) for a slotless electric motor (1), the slotless electric motor (1) comprising the stator (10) and a rotor (50) arranged to rotate around an axis of rotation (X), the stator (10) comprising at least a first layer or stratum made with a plurality of first coils (11, 12, 13) forming an armature (30) having a generally tubular shape arranged to receive the rotor (50), characterized in that each of the first coils (11, 12, 13): is formed with a wire having a rectangular cross section (11a), has two coil heads (11c, 11d) with: a first part (111, 114) of each coil head is positioned at a first radial distance from the axis of rotation (X), a second part (112, 115) of each coil head is positioned at a second radial distance from the axis of rotation (X), different from the first radial distance. 2. Stator (10) for a slotless electric motor (1) according to the preceding claim, wherein each coil end (11c, 11d) of each of the first coils (11, 12, 13) has a radial thickness, and in wherein the first radial distance differs from the second radial distance by at least the radial thickness. 3. Stator (10) for a slitless electric motor (1) according to any one of the preceding claims, wherein the second part (112, 115) of each of the first coils (11, 12, 13) is arranged at the- above the first part (111, 114) of the adjacent identical coil. A stator (10) for a slitless electric motor (1) according to any preceding claim, wherein the second part (112, 115) of each of the first coils (11, 12, 13) is arranged at the- below the first part (111, 114) of the adjacent identical coil. 5. Stator (10) for a slitless electric motor (1) according to any one of claims 1 to 2, wherein at least one of the second parts (112, 114) of the first coils (11, 12, 13 ) is arranged above the first part (111, 114) of the adjacent coil (11, 12, 13), and wherein at least one of the second parts (112, 115) of the first coils (11, 12, 13) is arranged below the first part (111, 114) of the adjacent coil (11, 12, 13) . A stator (10) for a slitless electric motor (1) according to any preceding claim, wherein the first coils (11, 12, 13) are surrounded by a second row of second coils. 7. Stator (10) for a slitless electric motor (1) according to any preceding claim, wherein the motor (1) has an air gap radius (70), and the smaller of the first radial distance and the second radial distance is greater than the gap radius (70). 8. Stator (10) for a slotless electric motor (1) according to any one of claims 1 to 6, wherein the motor (1) has an air gap radius (70), and the greater of the first radial distance and the second radial distance is less than the gap radius (70). 9. Slitless electric motor (1) comprising a rotor (50) and the stator (10) according to any one of the preceding claims. 10. A method for assembling a stator (10) according to any one of claims 1 to 8, wherein the method comprises at least: a step for nesting one of the first coils (11, 12, 13) with a coil (11, 12, 13) adjacent to the first coils (11, 12, 13).