Guide device for winding an electric machine rotor

Abstract

The invention relates to a guide device (1) for winding an electrically conductive wire (10) around a plurality of poles of a rotor (2) of an electric machine, the guide device (1) comprising a base (3) which has a central opening (O) configured to have the shaft of the rotor (2) passing through it, the base (3) having, on one side, an inner surface intended to face towards the poles of the rotor (2) and, on the other side, an outer surface (5), the inner surface (4) and the outer surface (5) being connected to one another by a side wall (6) from which radial arms (7) extend, the guide device (1) being characterized in that the side wall (6) has a first slot (8) and a second slot (9) which are configured to hold the electrically conductive wire (10), and in that the outer surface (5) has at least one guide rib (21, 22) configured to serve as a bearing surface for the electrically conductive wire (10).

Description

Guide device for winding an electric machine rotor.

[0001] The invention relates to the field of electrical machines comprising a wound rotor. More particularly, the invention relates to a guiding device for winding the rotor of an electrical machine. The invention further relates to an electrical machine equipped with such a guiding device.

[0002] Wound rotors for rotating electrical machines conventionally consist of a rotating shaft and a rotor body engaged on said shaft. The rotor body has a plurality of wound poles.

[0003] To ensure the flow of electric current through the winding, the rotor also includes a commutator, commonly called a "slip ring." This commutator is engaged on the shaft and generally bears against a shoulder machined into the shaft. Typically, the commutator has two hooks made of conductive material to which the two ends of the winding wire are attached. The winding wire is itself connected to an excitation system, such as a power supply.

[0004] To wind the winding wire around the poles, and before reaching the first pole to be wound, one free end of the wire is first attached to one of the two commutator hooks. This wire is then guided to the rotor body to be wound around the poles. Finally, a second free end of the wire is attached to the second hook.

[0005] The performance of an electric machine depends on the rotor's rotational speed. At maximum rotational speed (around 15,000 rpm), centrifugal force places significant stress on the rotor and its connected components, particularly the first and second free ends of the winding wire, which are attached to the two commutator hooks. To ensure the highest possible reliability of the electric machine, it is essential to maintain the position of these free ends of the winding wire when subjected to centrifugal force as well as the rotor's accelerations and decelerations. If the first and second free ends of the winding wire are not properly secured—that is, if they are not sufficiently taut or are even slack—the risk of breakage and / or cracking is very high.

[0006] The aim of the invention is to remedy the disadvantages described above by proposing a simple and effective solution for positioning the free ends of the winding wire so as to ensure sufficient support to resist centrifugal force as well as the accelerations and decelerations of the rotor when the electric machine is in operation.

[0007] To this end, the invention relates to a guiding device for winding an electrically conductive wire around a plurality of poles of a rotor of an electric machine, the guiding device comprising a base having a central opening configured to be traversed by the rotor shaft, the base having on one side an inner face intended to be oriented towards the rotor poles and on the other side an outer face, the inner face and the outer face being connected to each other by a side wall from which radial branches extend, the guiding device being characterized in that the side wall has a first notch and a second notch configured to receive the electrically conductive wire, and in that the outer face has at least one guiding rib configured to serve as a support surface for the electrically conductive wire.

[0008] According to one embodiment, the outer face of the base has a first guide rib and a second guide rib, extending between the central opening and the side wall of the base, and projecting from the outer face, the guide ribs being configured to serve as a bearing surface for the electrically conductive wire, the first notch extending in continuity with the first rib and the second notch extending in continuity with the second rib.

[0009] According to one embodiment, at least one guide rib has a curvature.

[0010] According to one embodiment, at least one guide rib has a tangent portion extending tangentially to the central opening of the base and / or a radial portion extending radially.

[0011] According to one embodiment, at least one guide rib has a boss that protrudes from a bearing face of at least one guide rib.

[0012] According to one embodiment, a height of the boss is less than or equal to a height of the guide rib.

[0013] According to one embodiment, at least one guide rib is made of material with the guide device.

[0014] According to one embodiment, at least one guide rib is a part attached to the base and configured to be mounted on the external face of the base.

[0015] According to one embodiment, the notches have a "V" shape.

[0016] According to one embodiment, the notches are arranged on either side of the same radial arm of the guiding device.

[0017] The invention also relates to an electric machine equipped with such a guiding device.

[0018] These objects, features and advantages of the present invention will be described in detail in the following description of a particular embodiment, given by way of non-limiting example, with reference to the accompanying figures, among which:

[0019] This is a perspective view of a guiding device for winding a rotor according to one embodiment.

[0020] This is a detailed view of the guidance system.

[0021] This is a second detailed view of the guidance device.

[0022] This is a third detailed view of the guidance device.

[0023] In this description, the terms "first," "second," "third," etc., are not intended to imply or create a particular order of elements, nor to limit an element to a single element, unless expressly stated, for example, by using terms like "before," "after," "unique," and other such terms. Rather, the use of these terms serves to distinguish elements from one another. For example, a first element is distinct from a second element, and the first element may encompass more than one element and follow (or precede) the second element in an order of elements.

[0024] In what follows, the terms "input" and "output" are defined with respect to the direction of the current supplying the rotor winding. The "first end" or "input portion" corresponds more specifically to a portion of the free end of the winding wire that runs from the first connection of the wire to a commutator towards the rotor poles, particularly towards the first pole of said rotor. Similarly, the "second end" or "output portion" corresponds more specifically to the portion of the wire that runs from the poles, particularly from the last pole of the rotor, towards a second connection of the wire to the commutator, forming another free end of the winding wire.

[0025] Figure 1 partially illustrates an electric machine. Only part of a wound rotor 2 is visible; the stator of the electric machine is not shown. An excitation device (not shown in the figure) is provided to supply the electric machine with an electric current, for example, a three-phase alternating current. In this way, the magnetic field created can vary, particularly in strength, thus influencing the direction and speed of rotation of the rotor 2.

[0026] The rotor 2 includes a shaft designed to be mounted to rotate about its axis of rotation in the stator. A stack of laminations (not shown in the figures) is arranged on the shaft of the rotor 2. The lamination stack forms a plurality of salient poles in a radial direction. A winding (not shown in the figures) is made with an electrically conductive wire wound around each pole.

[0027] Only a first end 11 (also called the "input portion") and a second end 12 (also called the "output portion") of the electrically conductive wire 10 are shown in the various figures. These first and second ends 11, 12 of the electrically conductive wire 10 allow the winding to be connected to a linking element with the excitation device mentioned previously.

[0028] The rotor 2 is equipped with a guide device 1 for winding the electrically conductive wire 10 around the poles. The guide device 1, illustrated in all the figures, is arranged on the shaft of the rotor 2 on the side of the poles where the connection element to the power supply system is located.

[0029] The guide device 1 comprises an annular base 3 with a central opening O configured to allow the rotor shaft 2 to pass through it, such that the axis of revolution of the base 3 is substantially coaxial with the axis of rotation of the rotor 2. The base 3 of the guide device 1 has, on one side, an inner face oriented towards the poles of the rotor 2, i.e., towards the interior of the electric machine, and on the other side, an outer face 5 oriented towards the commutator. The inner and outer faces 5 of the base 3 are substantially parallel to each other and connected by a lateral wall 6 from which radial branches 7 extend. The lateral wall 6 thus acts as a connecting wall linking the inner face to the outer face 5. In the embodiment illustrated in all the figures, the guide device 1 comprises eight radial branches 7 for eight poles.However, the number of radial branches and poles may be different.

[0030] The side wall 6 of the base 3 of the guide device 1 has a first notch 8 and a second notch 9 configured to receive the electrically conductive wire 10. More specifically, the side wall 6 of the base 3 has a first notch 8 configured to receive in its recess a portion of the first end 11 of the electrically conductive wire 10 and a second notch 9 configured to receive in its recess a portion of the second end 12 of the electrically conductive wire 10. These notches 8, 9 hold in place the first and second ends 11, 12 of the electrically conductive wire 10.

[0031] To facilitate the placement of the wire 10 during manufacturing, the notches 8, 9 have a "V" shape, as illustrated in Figures 3 and 4. In other words, the walls of the notches 8, 9 are inclined so as to facilitate the insertion of the wire 10 into said notches 8, 9. The "V" shape of these notches 8, 9 also helps to hold in place the ends 11, 12 of the winding wire 10 when they are subjected to the centrifugal force as well as the accelerations and decelerations of the rotor 2.

[0032] According to a preferred embodiment illustrated in all the figures, the notches 8, 9 are arranged on either side of the same radial arm 7 of the guide device 1. This arrangement of the notches 8, 9 on either side of the same radial arm 7 of the guide device 1 allows the first end 11 of the wire 10 to be separated from the second end 12 of the wire 10 in order to guarantee a sufficient electrical insulation distance to prevent the occurrence of an electric arc between these two ends 11, 12. This arrangement also saves on the conductive wire 10 by limiting, on the one hand, the distance between a first fixing and connection hook of the collector and the beginning of the winding, and on the other hand, the distance between a second fixing and connection hook of the collector and the end of the winding. However, other arrangements can be considered for these notches 8, 9.

[0033] Common to all embodiments, the outer face 5 of the base 3 of the guide device 1 has at least one guide rib 21, 22 configured to serve as a bearing surface for the electrically conductive wire 10. The guide rib(s) 21, 22 serve as a support to guide the electrically conductive wire 10 from the first commutator hook, to which the first end 11 of the conductive wire 10 is attached, to the rotor body 2, for winding around the poles. Similarly, the guide rib(s) 21, 22 serve as a support to guide the electrically conductive wire 10 from the pole winding to the second commutator hook, to which the second end 12 of the conductive wire 10 is attached. The ends 11, 12 of the electrically conductive wire 10 are intended to be pressed against a face of the guide rib(s) 21, 22.

[0034] According to an embodiment not shown in the figures, the same guide rib can serve as a bearing surface for both the first and second ends 12 of the conductor wire 10. This single guide rib is, for example, arranged in line with the central opening O of the base 3 of the guide device 1.

[0035] According to a preferred embodiment illustrated in all the figures, the outer face 5 of the base 3 has a guide rib 21 configured to guide the input portion, i.e., the first end 11 of the electrically conductive wire 10, from the first collector mounting and connection hook to the side wall 6 of the base 3; and a second guide rib 22, configured to guide the output portion, i.e., the second end 12 of the electrically conductive wire 10, from the winding, over the side wall 6 of the base 3, and to the second collector mounting and connection hook. In this embodiment, each end 11, 12 of the electrically conductive wire 10 is guided by its own guide rib 21, 22.

[0036] Using two separate guide ribs 21, 22 for the two ends 11, 12 of the conductive wire 10 saves on the length of conductive wire 10 by limiting, on the one hand, the distance between the first commutator hook and the beginning of the winding, and on the other hand, the distance between the second commutator hook and the end of the winding. Furthermore, using two separate guide ribs 21, 22 for the ends 11, 12 of the conductive wire 10 allows the tension applied to said ends 11, 12 of the wire 10 to be adjusted independently of each other to ensure they remain in position. In this embodiment, the shape of each guide rib 21, 22 can be optimized to ensure better guidance of the ends 11, 12 of the electrically conductive wire 10.

[0037] As illustrated in all the figures, the first and second guide ribs 21, 22 protrude from the outer face 5, they extend between the central opening O of the base 3 and the lateral wall 6 of the base 3. The first notch 8 extends in continuity with the first rib 21. In other words, a portion of a bearing face of the first rib 21 partially forms the first notch 8, so as to ensure smooth and precise guidance of the electrically conductive wire 10 from the first hook of the collector to the beginning of the winding. Similarly, the second notch 9 extends in continuity with the second rib 22. Here again, a portion of a bearing face of the second rib 22 partially forms the second notch 9 to ensure optimal guidance of the second end 12 of the electrically conductive wire 10 between the end of the winding and the second hook of the collector.

[0038] In a preferred embodiment, the guide rib(s) 21, 22 are curved to give them a J-shaped form, similar to a hook shape. This curvature of the guide ribs 21, 22 provides optimal guidance for the ends 11, 12 of the electrically conductive wire 10. In particular, the bearing surface against which the electrically conductive wire 10 is to be pressed may have a radius of curvature that allows adjustment of the tension exerted on the wire 10 to ensure that it remains in position when subjected to the movement of the rotor 2.

[0039] In the embodiment where the guide device 1 has two separate guide ribs 21, 22, the guide rib 21 has a curvature along a first direction while the second guide rib 22 has a curvature along a second direction, different and more particularly opposite to the first direction.

[0040] According to the embodiment illustrated in all the figures, each of the guide ribs 21, 22 has a tangent portion 23 extending tangentially to the central opening O and a radial portion 24 extending radially. This shape of the guide ribs 21, 22 increases the tension applied to the conductor wire 10 to ensure better retention of the wire 10. The shape of the guide ribs 21, 22 thus contributes to optimal guidance of the conductor wire 10 between the collector hooks and the notches 8, 9 present on the lateral wall 6 of the guide device 1.

[0041] In the embodiment where the guide device 1 has a first and a second guide rib 21, 22, each guide rib 21, 22 can have its own shape. Each guide rib 21, 22, for example, has its own radial portion 24 and its own tangent portion 23. There can be symmetry between the two ribs; in particular, the tangent portions of the ribs can be symmetrical to each other with respect to a radial plane passing through the center of the base 3. This is illustrated more particularly in Figures 2, 3, and 4.

[0042] According to one embodiment, the radial portion 24 of each guide rib 21, 22 projects from the outer face 5 and extends from the side wall 6 to midway along the outer face 5 of the base 3, between the central opening O and the side wall 6. The tangent portion 23 of each guide rib 21, 22 projects from the outer face 5 and extends tangentially in the continuation of an edge of the central opening O to an edge of the radial portion 24, where the tangent portion 23 and the radial portion 24 form a junction to together form the guide rib 21, 22 with a curved profile 10.

[0043] Optionally, the guide rib(s) 21, 22 each have a boss 25 which protrudes from the bearing face of the rib(s) 21, 22. Such a boss 25 may participate in guiding the electrically conductive wire 10 over at least a portion of the guide rib 21, 22.

[0044] More specifically, the height of the boss 25 can be less than or equal to the height of the guide rib. The height of the boss 25 and the height of the guide rib 21, 22 are measured in a direction parallel to the axis of rotation of the rotor 2. The top of the boss 25 then forms a step on which the electrically conductive wire 10 can bear, as illustrated in the figure. This limits the movement of the conductive wire 10 on the surface of the guide rib 21, 22, thus preventing friction that could damage the conductive wire 10 pressed against the bearing face of the guide rib 21, 22.

[0045] As illustrated in all the figures, at least one boss 25 has a rectangular shape. However, other shapes can be considered for the boss 25 on the guide rib(s) 21, 22. According to an embodiment not shown, the boss 25 may have a sloping portion, thus giving it a triangular shape. The sloping portion is oriented so as to guide the wire 10 towards the recess of a notch in the guide device 1.

[0046] In the embodiment where the guide has a first and a second guide rib 21, 22, each guide rib 21, 22 may have its own boss 25. The bosses 25 may be arranged so as to be located opposite each other, as illustrated in Figures 2, 3 and 4.

[0047] According to the embodiment illustrated in all the figures, the guide rib(s) 21, 22 are formed from the same material as the guide device 1; that is, the guide rib(s) 21, 22 and the guide device 1 form a single, monolithic part obtained during the same manufacturing process. The guide device 1, made of a non-conductive material, generally a plastic, is, for example, obtained using a molding process. Such a monolithic guide device 1 facilitates the manufacture of the device and can also facilitate its assembly in the electrical machine.

[0048] According to an alternative embodiment, each guide rib 21, 22 is an added component to the base 3, i.e., the guide rib(s) 21, 22 are separate parts from the base 3. In this embodiment, the guide rib(s) 21, 22 are configured to be mounted on the external face 5 of the base 3, either in a removable manner, for example by means of connecting elements such as clips, or permanently, for example by welding or any other suitable mounting method allowing a permanent fixed connection between the guide rib(s) 21, 22 and the guide device 1. This embodiment allows for more varied shapes for the guide rib(s) 21, 22 than in the embodiment where the guide rib(s) 21, 22 are formed as part of the material with the guide device 1.

[0049] It is thus possible to design a guide device 1 having particular characteristics such as at least one guide rib 21, 22 and notches 8, 9 allowing the free ends 11, 12 of the winding wire 10 to be positioned so as to ensure sufficient support of said wire 10 to resist the centrifugal force as well as the accelerations and decelerations of the rotor 2 when the electric machine is in operation.

Claims

A guiding device (1) for winding an electrically conductive wire (10) around a plurality of poles of a rotor (2) of an electric machine, the guiding device (1) comprising a base (3) having a central opening (O) configured to be traversed by the rotor shaft (2), the base (3) having on one side an inner face intended to be oriented towards the poles of the rotor (2) and on the other side an outer face (5), the inner face (4) and the outer face (5) being connected to each other by a side wall (6) from which radial arms (7) extend, the guiding device (1) being characterized in that the side wall (6) has a first notch (8) and a second notch (9) configured to receive the electrically conductive wire (10), and in that the outer face (5) has at least one guiding rib (21, 22) configured to serve as a bearing surface for the wire (10) electrically conductive. A guiding device according to the preceding claim, characterized in that the external face (5) of the base (3) has a first guiding rib (21) and a second guiding rib (22) extending between the central opening (O) and the lateral wall (6) of the base (3) and projecting from the external face (5), the guiding ribs (21, 22) being configured to serve as a bearing surface for the electrically conductive wire (10), and characterized in that the first notch (8) extends in continuity with the first rib (21) and the second notch (9) extends in continuity with the second rib (22). A guidance device according to the preceding claim, characterized in that at least one guide rib (21, 22) has a curvature. A guidance device according to the preceding claim, characterized in that at least one guide rib (21, 22) has a tangent portion (23) extending tangentially to the central opening (O) of the base (3) and / or a radial portion (24) extending radially. A guidance device according to one of the preceding claims, characterized in that at least one guide rib (21, 22) has a boss (25) which protrudes from a bearing face of at least one guide rib (21, 22). A guidance device according to the preceding claim, characterized in that a height of the boss (25) is less than or equal to a height of the guide rib (21, 22). A guidance device according to one of the preceding claims, characterized in that at least one guide rib (21, 22) comes from the material with the guidance device (1). Guide device according to any one of claims 1 to 6, characterized in that at least one guide rib is an added part to the base (3) and configured to be mounted on the external face (5) of the base (3). A guidance device according to one of the preceding claims, characterized in that the notches (8, 9) have a "V" shape. A guidance device according to one of the preceding claims, characterized in that the notches (8, 9) are arranged on either side of the same radial arm (7) of the guidance device (1). Electric machine comprising a guiding device (1) according to one of the preceding claims.

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