Woven electromagnetic mat and method for connection of ends thereof

The present invention is related to a woven electromagnetic mat, according to the preamble of claim 1.

The present invention is also related to a method for connection of ends of a woven electromagnetic mat, according to the preamble of claim 10.

The present invention is especially related to the use of a woven electromagnetic mat as a winding in a stator or rotor component of an electric machine.

Background

Ironless and slotless permanent magnet electric machines gain attention of both the research and the industrial communities due to certain advantages over the conventional technologies. These new machine types find market applications such as in drones, automation, robotics, medical devices, etc. The main enabling component of an ironless/slotless machine is the slotless stator or rotor, not containing any iron/ferromagnetic parts such as teeth.

There exist many methods for production of such windings, one of them is disclosed in WO2019074375 Al, in the name of the applicant. This method includes, among other variants, the steps of producing (weaving) an electromagnetic mat made of copper wires and using non- conductive warps to hold the wires in place, as shown in Fig. 1, then making the electromagnetic mat into a ring and molding it into some matrix material, such as epoxy, thus producing a composite ring, as shown in Fig. 2. WO2019074375A1 does not disclose any method for connection of the ends of the electromagnetic mat, especially into the ring.

The challenge of connection of the ends of woven structures, especially into a ring-shaped object, is also known from textile industry, for example from JPS4880861 A, as shown in Fig. 3.

Prior art reversals several methods for connection of ends of mats and bands. In, e.g., DE3628762 Al is disclosed a method of connecting mats, in JP2000302881 A is disclosed a jointed mat and production of fiber reinforced thermoplastic sheet, in US3474507 A is disclosed a method and means for connecting woven bands, while in JP2686540 B2 is disclosed a net for civil engineering work and its laying method. However, none of these inventions are applicable for electromagnetic mats for electric machines, due to they all bring in extra components that remain in the place of connection.

In JP2013014861 A a method and an arrangement for connection of mats are disclosed, however it is complex and, as in the previously mentioned cases, the result of application of the method is extra element attached to the mat, which is not optimal for circular electromagnetic mats like in WO2019074375 Al due to such mats need to have a uniform structure to be molded into a matrix material to form a composite ring.

The prior art solutions thus fail to disclose a woven electromagnetic mat, suitable for use in windings of ironless/slottless electric machines, with electrical connection at ends thereof and a method of connection of the ends thereof.

There is accordingly a need for a woven electromagnetic mat and method for connection of ends thereof enabling the use of electromagnetic mats as windings of high-performance slotless and ironless electric machines.

There is further a need for a woven electromagnetic mat and method for connection of ends thereof enabling forming the woven electromagnetic mat as a circular object.

Further, there is a need for a woven electromagnetic mat and method for connection of ends thereof applicable to a wide variety of winding topologies and patterns and possible to automate.

Object

The main object of the present invention is to provide a woven electromagnetic mat and method for connection of ends thereof partly or entirely solving the mentioned drawbacks and/or needs of prior art.

An object of the present invention is to provide a woven electromagnetic mat and method for connection of ends thereof enabling forming of a ring-shaped woven electromagnetic mat for a stator or rotor component of an electric machine.

It is further an object of the present invention to provide a woven electromagnetic mat and method for connection of ends thereof enabling a wide variety of winding patterns. An object of the present invention is to provide a woven electromagnetic mat and method for connection of ends thereof enabling forming a ring-shaped woven electromagnetic mat that can be moulded with a curable liquid potting material, as epoxy/resin, to ensure higher mechanical strength, improved heat transfer, etc. for the stator or rotor component.

It is an object of the present invention to provide a woven electromagnetic mat and method for connection of ends thereof enabling forming of a ring-shaped woven electromagnetic mat that is cost-efficient and possible to automate.

Further objects of the present invention will appear from the following description, claims and attached drawings.

The invention

A woven electromagnetic mat suitable for use as a winding in a stator or rotor component of an electric machine according to the present invention is defined by the technical features of claim 1. Preferable features of the woven electromagnetic mat are described in the dependent claims.

A method of connecting ends of a woven electromagnetic mat suitable for use as a winding in a stator or rotor component of an electric machine according to the present invention is defined by the technical features of claim 10. Preferable features of the method are described in the dependent claims.

Woven electromagnetic mats suitable for use as a winding in a stator or rotor component of an electric machine can be produced as substantially flat strips, which next is bent and connected at ends thereof to form ring-shaped woven electromagnetic mat.

According to the present invention, the woven electromagnetic mat comprises a winding formed by at least two phase conductors woven with warps. The warps may, according to the present invention be non-conductive or partially or fully conductive. In most cases, non-conductive warps are used. According to the present invention, the woven electromagnetic mat comprises first and second ends, which are to be connected to provide a continuous winding of a desired winding pattern.

The at least two phase conductors have, according to the present invention, parts thereof arranged (extending) in transversal direction relative to the length of the woven electromagnetic mat, belonging to active area of the winding, and parts thereof arranged (extending) in substantially longitudinal direction relative to the length of the electromagnetic mat, belonging to end-windings.

According to one embodiment of the present invention one of or both the first and second end of the woven electromagnetic mat is/are provided with at least one fixation element or temporary fixation device enabling connection of the ends and arrangement of the phase conductors to achieve a continuous winding.

By means of the mentioned at least one fixation element or temporary fixation device, the first and second end of the woven electromagnetic mat can be connected to form a ring-shaped woven electromagnetic mat that can be used as a winding in a stator or rotor component of an electrical machine.

The mentioned woven electromagnetic mat can be formed by sections or several woven electromagnetic mats that are connected in series by the principles of connection and forming of a continuous winding herein.

The method for connecting ends of a woven electromagnetic mat according to the present invention comprises an initial step of the present invention is to produce a substantially flat woven electromagnetic mat as described above, e.g. by using the method described in WO2019074375 Al, in the name of the applicant, the disclosure of which is incorporated herein by reference.

The method according to the present invention comprises arranging or integrating, during weaving, at least one fixation element or temporary fixation device in a spacing between phase conductors or in an end area of one or both ends of the woven electromagnetic mat.

The present invention comprises bending or rolling the woven electromagnetic mat into a ringshape and connecting the ends of the woven electromagnetic mat to form a continuous winding.

According to one embodiment of the present invention, the method comprises arranging the phase conductors, at connecting of the first and second end of the woven electromagnetic mat, in a desired winding pattern to form the continuous winding.

In accordance with one embodiment of the method according to the present invention, it comprises connecting at least one fixation element arranged at one end of the woven electromagnetic mat to at least one phase conductor at the other end of the woven electromagnetic mat. Connecting the fixation element to the phase conductor may be performed by means of e.g. gluing or other suitable non-conductive attachment method. According to an alternative embodiment of the present invention, the method comprises inserting at least one phase conductor of one end of the woven electromagnetic mat having extra length outside the active area of the winding in at least one temporary hollow fixation device arranged in the other end of the woven electromagnetic mat and passing the mentioned phase conductor through the temporary hollow fixation device arranging the phase conductor in a final position in the winding.

In accordance with a further alternative embodiment of the method according to the present invention, the method comprises inserting at least one phase conductor of the first end of the woven electromagnetic mat having extra length outside the active area of the winding in at least one temporary fixation device arranged in the second end of the woven electromagnetic mat and passing it through the temporary hollow fixation device arranging the phase conductor in a final position in the winding. This embodiment of the method further comprising inserting at least one phase conductor of the second end of the woven electromagnetic mat having extra length outside the active area of the winding in at least one temporary fixation device arranged in the first end of the woven electromagnetic mat and passing it through the temporary hollow fixation device arranging the phase conductor in a final position in the winding.

According to a further embodiment of the present invention, the method comprises connecting end of at least one phase conductor of one end of the woven electromagnetic mat having extra length outside the active area of the winding to at least one temporary fixation device arranged in the other end of the woven electromagnetic mat.

In accordance with one embodiment of the present invention the method comprises connecting end of at least one phase conductor of the first end of the woven electromagnetic mat having extra length outside the active area of the winding to at least one temporary fixation device arranged in the second end of the woven electromagnetic mat and connecting end of at least one phase conductor of the second end of the woven electromagnetic mat having extra length outside the active area of the winding to at least one temporary fixation device arranged in the first end of the woven electromagnetic mat

The method according to the present invention according to a further embodiment comprises removing or eliminating the temporary fixation device from the woven electromagnetic mat

The method according to the present invention in accordance with one embodiment comprises an initial step of producing a substantially flat woven electromagnetic mat with at least one fixation element or temporary fixation device woven therein at one or both ends thereof in a free space between the phase conductors or end area thereof.

In accordance with a further embodiment of the present invention, the method further compromises an initial step of producing the woven electromagnetic mat with at least one phase conductor having extra length outside the active area of the winding at one or both ends of the woven electromagnetic mat.

According to one embodiment of the present invention, the method comprises forming the woven electromagnetic mat by connecting sections or several woven electromagnetic mats in series at respective first and second ends thereof.

In this manner, the woven electromagnetic mat and method for connection of ends thereof enable forming a ring-shaped woven electromagnetic mat being suitable to be moulded with a curable liquid potting material, as epoxy/resin, to ensure high mechanical strength, improved heat transfer, etc. for a stator or rotor component.

Further preferable features and advantageous details of the present invention will appear from the following example description, claims and attached drawings.

Example

The present invention will below be described in further detail with reference the attached drawings of non-limiting examples, where:

Fig. 1 is a principle drawing of an electromagnetic mat according to prior art,

Fig. 2 is a principle drawing of the electromagnetic mat in Fig. 1 shaped as a ring,

Fig. 3 is a principle drawing of a prior art example of a strip of a woven cloth connected into a ring,

Fig. 4a-c are principle drawings of a first embodiment of the present invention,

Fig. 5a-b are principle drawings connection of the two ends of the woven electromagnetic mat according to the present inventing,

Fig. 6 is a principle drawing of a connected woven electromagnetic mat according to the present invention, Fig. 7a-c are principle drawings of a further embodiment of the present invention, using a tubular hollow placeholder, and

Fig. 8a-c are principle drawing of a further embodiment of the present invention using two tubular hollow placeholders.

Reference is now made to Figure 1 showing a principle drawing of a woven electromagnetic mat 10 according to prior art, wherein warps 20, non-conductive warps, are holding phase conductors of a winding 30 in place.

Reference is now made to Figure 2, which is a principle drawing of the electromagnetic mat 10 in Fig. 1, shaped as a ring.

Reference is now made to Figure 3 showing a further example of prior art, in the form of a strip of a woven cloth 3 connected into a ring 1.

Reference is now made to Figure 4a-c, which are principle drawings of a woven electromagnetic mat 10 according to a first embodiment of the present invention comprising two ends 40a-b and how it can be bent or rolled (Fig. 4b) into a ring-shape and wherein the ends 40a-b are forming an overlapping structure to form a continuous winding 30 with at least one phase.

According to the present invention, the mentioned two ends 40a-b form first 40a and second 40b ends of the woven electromagnetic mat 10. In accordance with the present invention, the first end 40a of the woven electromagnetic mat 10 according to the present invention contains first ends A, B, C of phase conductors 41-43 and the second end 40b contains second ends A', B', C' of the mentioned phase conductors 41-43.

Accordingly, the woven electromagnetic mat 10 according to the present invention comprises at least two phase two phases provided by at least two phase conductors 41-42 having parts 50 of the phase conductors 41-43 extending in transversal direction relative to the length of the woven electromagnetic mat 10, belonging to active area of the winding 30, and parts 60 of the phase conductors 41-43 extending in substantially longitudinal direction relative to the length of the woven electromagnetic mat 10, forming end-windings, thus providing a continuous winding 30 extending from one end 40a to the other end 40b of the woven electromagnetic mat 10 with desired winding pattern and properties. As shown in Fig. 4a, there is an empty space 44a in the winding 30 in the first end 30 of the electromagnetic mat 10 and similarly an empty space 44b in the winding 30 in the second end of the electromagnetic mat 10, i.e. between the two outermost phase conductors 42 and 43 at the first end 40a and between the two outermost phase conductors 41 and 42 at the second end 40b.

As Fig. 4a shows, the respective ends A, B, C, A', B', C' of the respective phase conductors 41-43 are protruding out of the woven electromagnetic mat 10 enabling them to be connected to winding terminals (not shown).

Reference is now made to Figure 4b, which is a principle drawing of the woven electromagnetic mat 10 according to the present invention bent or rolled into a ring-shape, and wherein the first end 40a of the woven electromagnetic mat 10 and the second end 40b of the woven electromagnetic mat 10 are ready for connection.

Reference is now made to Figure 4c showing an embodiment of the present invention wherein the first 40a and second 40b end of the woven electromagnetic mat 10 has been arranged in overlapping position to form continuous winding 30, by movement of the first 40a and second 40b ends in relation to each other, such that the outermost phase conductors 43 of the first end 40a and the outermost phase conductor 41 of the second end 40b are moved into the mentioned respective space 44a-b of the other end 40a-b. In this manner, there is provided a winding 30 wherein the same pattern/sequence (phase A-B-C-A-B-C...) of the phase conductors 41-43 is maintained along the circumference of the ring-shaped woven electromagnetic mat 10. In the embodiment in Fig. 4c, the ends A-C, A'-C' of phase conductors 41-43 are not fixed to anything or held in place by anything. There is accordingly a need for at least one fixation element 45a-b, 46 for retaining the phase conductors 41-43.

Reference is now made to Figures 5a-b showing a further embodiment of the woven electromagnetic mat 10 according to the present invention, wherein fixation elements 45a-b in the form of placeholders are integrated at the respective ends 40a-b of the woven electromagnetic mat 10. Figures 5a-b also show the process of connection of the mentioned ends 40a-b of the electromagnetic mat 10 by means of the fixation elements 45a-b. In the embodiment in Figures Safa, the fixation elements 45a-b are woven into the woven electromagnetic mat 10 by warps 20, at both ends thereof. According to the present invention, the warps 20 may be non-conductive or partially or fully conductive. In most cases, non-conductive warps 20 are used. In the shown embodiment the fixation elements 45a-b are fabric-like structures of mainly rectangular shape, but the shape and size thereof may vary depending on the properties of the woven electromagnetic mat 10. When the two ends 40a-b of the electromagnetic mat 10 are arranged into overlapping position as shown in Figure 5b, the fixation elements 45a-b (placeholders) can be attached to, e.g. by means of glue or other suitable attachment means, to the respective other end 40a-b of the electromagnetic mat 10.

Reference is now made to Figure 6 showing the woven electromagnetic mat 10 according to the invention. The woven electromagnetic mat 10 contains the warps 20 holding the phase conductors 41-43 together.

According to one embodiment of the present invention, the warps 20 of both ends 40a-b of the woven electromagnetic mat 10 are terminated with knots 21.

In accordance with one embodiment of the present invention, the woven electromagnetic mat 10 at one end thereof, in the shown example the first end 40a, contains a temporary fixation device 46, such as a placeholder, woven into the warps 20, in the free space 44a between the outermost phase conductors 42, 43. The temporary fixation device 46 has a width substantially close to the thickness of a phase conductor 41-43 in active area 50 of the winding 30.

The other end of the electromagnetic mat 10, in the example the second end 40b, the outermost phase conductor 41 has extra length, compared to the others, where it goes out of the warps 20. According to one embodiment, the temporary fixation device 46 is a hollow tubular structure, adapted for receiving the mentioned phase conductor 41 of extra length, which temporary fixation device 46 are woven into the woven electromagnetic mat 10, in transversal direction thereof.

Reference is now made to Figures 7a-c showing the process of connection of the two ends 40a-b of the electromagnetic mat 10 by using the mentioned temporary fixation device 46. When the two ends 40a-b of the woven electromagnetic mat 10 are moved towards each other, as shown in Figure 7a, the mentioned longer phase conductor 41 from the second end 40b of the woven electromagnetic mat 10 is inserted into and extending through the temporary fixation device 46, such that the longer phase conductor 41 takes its final position in the woven electromagnetic mat 10, as shown in Figure 7b. The temporary fixation device 46 or placeholder 46 is then removed or eliminated from the woven electromagnetic mat 10, as shown in Figure 7c, thus properly connecting the two ends 40a-b of the woven electromagnetic mat 10, as well as providing a woven electromagnetic mat 10 free from any elements not needed in the winding 30 of an electric machine.

Reference is now made to Figures 8a-c showing a further embodiment of the present invention wherein the woven electromagnetic mat 10 is proved with one temporary fixation devices 46a-b or placeholders, as described above, at each of the distal ends thereof, woven into the woven electromagnetic mat 10 in front of the termination 21 of the warps 20. The temporary fixation devices 46a-b has a width substantially close to the thickness of a phase conductor 41-43 in active area 50 of the winding 30.

In accordance with this embodiment, the outermost phase conductors 41 and 43 of the respective ends 40a-b have extra length, compared to the others, where it goes out of the warps 20.

When the two ends 40a-b of the woven electromagnetic mat 10 are moved towards each other, as shown in Figure 8a, the longer phase conductor 41 from the second end 40b of the woven electromagnetic mat 10 is inserted into and moved through the temporary fixation device 46a or placeholder in the first end 40a, so that the longer phase conductor 41 takes its final position in the woven electromagnetic mat 10, as shown in Figure 8b. Similarly, the longer phase conductor 43 from the first end 40a of the woven electromagnetic mat 10 is inserted into and moved through the temporary fixation device 46b or placeholder in the second end 40b, so that the longer phase conductor 43 takes its final position in the woven electromagnetic mat 10, as shown in Figure 8b. The temporary fixation devices or placeholders 46a-b are then removed or eliminated from the woven electromagnetic mat 10, as shown in Figure 8c, wherein the two ends 40a-b of the woven electromagnetic mat 10 are properly connected and wherein the woven electromagnetic mat 10 is free from any elements not needed in the winding 30 of an electric machine.

The above-described embodiments can be combined and modified to form other embodiments within the scope of the claims.

Modifications

According to one modification of the present invention, the mentioned temporary fixation device(s) or placeholder(s) can be solid (not hollow) tubular structure. In this manner the end of the longer phase conductor can be connected to the end of the mentioned temporary fixation device or placeholder and take its position in the woven electromagnetic mat when the mentioned temporary fixation device or placeholder is pulled away and out of the woven electromagnetic mat.

In a further modification, the ends of the phase conductors can be on both sides of the woven electromagnetic mat. Thus, the connections or terminals can be on one side of the woven electromagnetic mat or on opposite side of the woven electromagnetic mat. In a further modification, there can be any number of phases in the woven electromagnetic mat and the winding patterns can be any as well.

In a further modification, there can be several woven electromagnetic mats connected in series. In such an application, the above described methods and fixation elements or temporary fixation device(s) are used for connecting respective ends of two different mats.

In a further modification, several woven electromagnetic mats connected in series can form a circular object.

In a further modification, the warps can be partially or fully conductive.

List of designations

10 - woven electromagnetic mat bent into a ring-shape

20 -warps

21 - knots (termination of the warps)

30 - winding

40a - first end of the woven electromagnetic mat

40b - second end of the woven electromagnetic mat

41 - phase conductor phase A of the winding

42 - phase conductor phase B of the winding

43 - phase conductor phase C of the winding

44a - empty space in the winding 30 in the first end 40a of the woven electromagnetic mat 10

44b - empty space in the winding 30 in the second end 40b of the woven electromagnetic mat 10

45a-b - fixation element

46, 46a-b - temporary fixation device or placeholder

A - first end of phase conductor 41

A' - second end of phase conductor 41

B - first end of phase conductor 42

B' - second end of phase conductor 42

C - first end of phase conductor 43

C' - second end of phase conductor 43

50 - active part of a phase conductor

60 - end-winding part of a phase conductor