Slip ring, rotating electrical machine, and method for manufacturing and assembling slip ring

Abstract

The invention relates to a slip ring (A), a rotating electrical machine and a method for manufacturing and assembling a slip ring. The collector ring is formed by a circular support (1) formed by a set of insulating plates comprising a plurality of through-holes (2) arranged along the circumference thereof and a plurality of protrusions (9) arranged radially outward with respect to the center of said ring, this ring being fastened against the stator core (7) by reversible fastening elements (6), and further comprising a plurality of 'L'-shaped connecting strips (4) and 'Z'-shaped connecting strips (5), a plurality of 'L'-shaped connecting strips (4) and 'Z'-shaped connecting strips (5) are arranged in the holes (2) in a staggered manner along the circumference of the circular support (1). Since both the coil terminal (8) and the cable terminal (11) can be electrically connected to each other using the connecting strips (4) and (5), the 'L'-shaped and 'Z'-shaped connecting strips allow for the elimination of the need for welding in the connection between the start and end of the coil assembly and their respective connecting cables.

Description

Technical Field

[0001] The present invention is generally in the field of rotating electrical machines, in particular electrical machines comprising a stator. More particularly, the present invention relates to machines comprising slip rings particularly adapted for mechanical connection to a stator. Background Art

[0002] The fastening of connecting cables to the stator of rotating electrical machines has a long history of development and improvement over the years. This fastening is an important part of the construction process of electric motors and generators, as it ensures a safe and reliable connection between the stator windings and external components of the electrical system.

[0003] In the early days of electric motor development, the machines were relatively simple and small. The stator windings were made of thick, rigid wire and were typically fastened with hand-knotted rope or wire. This method was laborious and required skill to ensure a secure and even connection.

[0004] As technology progressed and the demand for more powerful and efficient electric motors grew, the fastening of connecting cables needed to be improved, and with the advent of more advanced materials such as resins and engineering plastics, new fastening techniques were developed.

[0005] Proper tightening of connecting cables is critical to ensuring the performance and reliability of rotating electrical machines. Incorrect connections can cause operational problems such as excessive heating, vibration, loss of efficiency, and even catastrophic failure. Therefore, continued improvement in tightening technology is an important aspect of continuous improvement and innovation in the electric motor and generator industry.

[0006] However, it should be emphasized that in most large and / or high voltage rotating electrical machines, the connection cables are currently still fastened to the stator by welding applied directly to the coils, wherein if the connection cables eventually need to be replaced on site, it is time-consuming and risky, since the removal of the welds may damage the stator insulation and / or other components, which may seriously affect the operation of the equipment. It should be further emphasized that the conventional way of connecting the connection cables to the stator coils by welding leads to high manufacturing costs, since such a manufacturing process requires the operator to adopt means of temporarily thermally isolating the motor coils and then perform the welding process. After the welding process, this thermal insulation must be removed. If the insulation process is not performed properly, the electrical insulation of the stator may be damaged due to the high heat input generated by the welding process. In addition to not adding direct value to the final product, such a thermal insulation process and its subsequent removal is known to be time-consuming and expensive in terms of manufacturing efficiency.

[0007] Prior art

[0008] Some documents of the prior art disclose technologies that meet the same objectives as the present invention, but still have unresolved deficiencies regarding the fastening of the connecting cables.

[0009] Document JP2019170013 provides a motor and an electric steering device that can easily fasten busbars and spacers, including a rotor, a stator, and a busbar unit. The busbar unit includes a plurality of axially overlapping busbars electrically connected to the coil, an insulating spacer disposed between the busbars, and a busbar support that holds the busbars and the spacers, wherein the busbar support in turn includes a body that holds the busbar from the lower side and a protrusion that extends upward from the upper surface of the body. The busbar and the spacer have through holes that allow the protrusion to pass through in the vertical direction.

[0010] The document JP2019170013 further establishes that the method of fastening the protruding portion to the busbar and the spacer can be thermal welding. Therefore, by thermally welding the upper busbar protrusion, the lower busbar and the spacer are fastened.

[0011] Therefore, according to what is disclosed in document JP2019170013, it is determined that a thermal welding process is still required to fasten the busbars, since said document does not completely eliminate the need for welding operations that would greatly complicate a possible replacement of the cable on site.

[0012] Regarding document US 10,250,096 B2, it should be emphasized that it discloses a rotating electric machine in which the insulation capacity of the busbar unit is maintained to supply current to the coil of the stator of the rotating electric machine. In an arc-shaped busbar unit stacked and arranged at one end of the stator coil, a neutral point busbar unit is arranged at the midpoint of a phase busbar unit, which also includes a phase busbar. Figure 3 The figure shows a plan view, disclosing a stator bus bar unit in a rotating electric machine in the case where the bus bar units are stacked. Figure 4 Indicates along the Figure 3 A state of a cross section of line “AA” in FIG. 1 is illustrated in which a resin is molded around a bus bar having a thin plate shape in each of the bus bar units, a resin layer is formed on each of the bus bar units, and an insulation process is performed.

[0013] According to the disclosure in document US 10,250,096 B2, the central problem to be solved is related to the fact that the overall height of the stator is increased. In short, the document discloses the presence of conductive elements coated with insulating resin, wherein these insulating elements are then stacked in arc-shaped busbar units. In this way, the disclosure in the above-mentioned US document aims to solve this specific problem related to the height of the stator and does not provide any motivation to eliminate the process of welding the connecting cables directly to the stator coils.

[0014] Therefore, it has been determined that none of the prior art documents discloses the problems associated with solving the eventual need for field replacement of connection cables welded directly to the stator and the difficulty in implementing the manufacturing process. Summary of the invention

[0015] The solution proposed by the invention aims at eliminating the welding process applied to the stator connection cables and the difficulties associated with this process, allowing an overall adaptation of the specifications of the equipment in order to easily replace the stator connection cables when necessary.

[0016] The invention relates to a stator slip ring (A), wherein the stator slip ring is constructed of a circular support (1), the circular support (1) being formed by a set of insulating plates, the set of insulating plates comprising a plurality of through holes (2) arranged along the circumference thereof and a plurality of protrusions (9) arranged radially outwardly relative to the center of the ring, wherein the protrusions also comprise through holes (3).

[0017] A plurality of "L"-shaped connecting strips (4) and "Z"-shaped connecting strips (5) are arranged in a staggered manner in the holes (2) along the circumference of the circular support (1). In this way, since both the coil terminals (8) and the cable terminals (11) can be electrically connected to each other through the connecting strips (4) and (5), the presence of the "L"-shaped connecting strips and the "Z"-shaped connecting strips eliminates the need for welding in the connection between the beginning and the end of the coil group and their corresponding connecting cables. Since opening the welded connection may damage the stator insulation and / or other components, eliminating the welding operation facilitates the eventual need to replace the connecting cables on site, takes less time and has less technical risk. Therefore, one advantage of the present invention is that the connecting cables can only be replaced by using reversible mechanical fastening elements, thereby providing high productivity in the manufacture of the equipment, providing higher reliability during its manufacture, and being easier to maintain. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] To help identify the main features of the present invention, the accompanying drawings to be referenced are presented below:

[0019] Figure 1 A perspective view of a slip ring mounted to a stator is shown.

[0020] Figure 2 The diagram shows a side view of a slip ring mounted on a stator, including a connection cable (10) connected to a cable terminal (11).

[0021] Figure 3 The figure shows a front view of the slip rings mounted on the stator.

[0022] Figure 4A perspective view of a slip ring is shown with emphasis on the assembled coil terminals (8) and cable terminals (11), where terminals (4A) and (5A) are the connection points for the cable and terminal (5B) is the connection point for the coil.

[0023] Figure 5 The figure shows a perspective view of the slip ring, focusing on the "Z" shaped connecting strips (5) and "L" shaped connecting strips (4) installed in a staggered manner.

[0024] Fig. 6A , Figure 6B and Figure 6C The rear plate (1B), the front plate (1A) and the circular insulating support (1) formed by connecting the plates are shown respectively.

[0025] Figure 7 The figure shows a slip ring mounted on a stator, with a connecting cable (10) connected to a cable terminal (11).

[0026] Figure 8 The minimum radial dimension (R) formed by the slip ring (A) is shown.

[0027] Fig. 9 An "L-shaped" connecting strip (4) is shown in detail, having terminals (4A, 4B) and a central portion (40) thereof.

[0028] Fig.10 The "Z" shaped connecting strip (5) is shown in detail, and has terminals (5A, 5B) and a central portion (50).

[0029] Fig.11 A first alternative configuration of a circular support (1) is shown, in which only "Z" shaped connecting strips (5) are installed in an alternating manner.

[0030] Fig.12 A second alternative configuration of the circular support (1) is illustrated, wherein only the "L" shaped connecting strips (4) are installed in an alternating manner. DETAILED DESCRIPTION

[0031] The present invention discloses a stator slip ring (A), such as Figure 1 As shown in the figure, the slip ring (A) includes a circular support (1), which is formed by a set of insulating plates (1A) and (1B) and includes a plurality of through holes (2) arranged along its circumference and a plurality of protrusions (9) arranged radially outward relative to the center of the connecting ring (A). The protrusions (9) also include through holes (3).

[0032] As in Figure 1 and Figure 2As can be seen in the figure, the slip ring (A) is concentrically mounted to the stator by means of a plurality of reversible fastening elements (6), which are suitable for mechanically fastening the circular support (1) of the slip ring (A) to the stator core (7) through the through holes (3) located in the protrusions (9).

[0033] The reversible fastening element (6) may be a threaded component, a smooth fastening element such as a pin or any other element that allows a complete mechanical separation between the slip ring (A) and the stator.

[0034] The total length of the reversible fastening element (6) is determined by the length of the coil head of the stator plus the gap required for connecting the coil terminals and the electrical distance between the energized components. Figure 2 As indicated in , in a preferred embodiment, the lower face of the insulating plate (1B) must be at a minimum distance (H) of 100 mm from the end of the stator coil head.

[0035] The minimum radial dimension (R) formed by the slip ring (A) and the set of assembled connecting strips (4) and (5) and the corresponding crimped cables (10) must be sufficient to insert the rotor (12) loosely into the stator so that the arrangement of the connecting cables does not exceed the inner diameter of the stator, e.g. Figure 8 as shown in .

[0036] In a preferred embodiment, the distance between the innermost surface of the connecting strips (4) and (5) and the outer diameter of the rotor (12) must be at least 15 mm, preferably greater than 25 mm. This distance must accommodate the connecting strips (4, 5) and their corresponding screws without obstructing the area used to mount the rotor (12), which is located in the Figure 8 Indicated by the shaded area.

[0037] As in Figure 3 It can be seen that each hole (2) is positioned at a distance (D) of at least 50 mm relative to the adjacent hole (2) along the circumference of the circular support (1).

[0038] It is worth mentioning that the minimum distance "D" is defined in order to avoid short circuits due to insufficient proximity between the terminals of the connecting strips (4) and (5), which are arranged along the circumference of the circular support (1).

[0039] As in Figure 1 It can be seen that in a preferred embodiment, the connecting strips (4) and (5) are respectively "L"-shaped and "Z"-shaped, and are arranged in a staggered manner along the circumference of the circular support member (1), wherein both the connecting strips (4) and (5) are axially fastened in the through hole (2) of the circular support member (1).

[0040] The "L"-shaped connecting strip (4) and the "Z"-shaped connecting strip (5) are made of a current conducting material, preferably tinned copper. On the other hand, the circular support (1) must be made of an electrically insulating material, preferably a polymer or composite material, and more preferably fiberglass, and further consists of joining two or more insulating plates, such as, for example Fig. 6A and Figure 6B It is composed of plates (1A) and (1B) shown in FIG.

[0041] The choice of insulating material is necessary because the circulation of current around the circumference of the bus ring (A) cannot occur and must be limited to the connecting bar, whether it is an "L" shaped connecting bar (4) or a "Z" shaped connecting bar (5). The main function of the bus ring (A) is to support the connecting bars (4) and (5), wherein this support is provided by positioning the connecting bars (4) and (5) between the joints of the insulating plates (1A) and (1B) and by fastening the connecting bars (4) and (5) in the holes (2).

[0042] The "L"-shaped connecting strip (4) and the "Z"-shaped connecting strip (5) include connection points (4B) and (5B) for coil terminals and connection points (4A) and (5A) for connecting cables, as shown in Figure 4 and 5 It can be seen in.

[0043] As in Figure 5 and FIG. 6A to FIG. 6C As can be seen in the figure, each "L"-shaped connecting strip is arranged between the set of plates (1A) and (1B) forming the circular support (1), so that the terminal (4A) extends radially outward from the circumference of the circular support (1), while the other terminal (4B) extends axially inward relative to the stator axis.

[0044] As in Figure 5 As can be seen in the figure, each "Z"-shaped connecting strip is also arranged between the set of plates (1A) and (1B) forming the circular support (1), so that the terminal (5A) extends axially outward from the circumference of the circular support (1), while the other terminal (5B) extends axially inward relative to the stator axis.

[0045] The front plate (1A) includes a hole (20) along its circumference, and the rear plate (1B) includes a recess (30) along its circumference, the recess also includes a hole (25), the hole (25) is concentric with the hole (20) in the front plate (1A), as shown in Fig. 6A and Figure 6B It can be seen in.

[0046] Each recess (30) provides sufficient space to accommodate the central portion (40) of the "L"-shaped connecting strip (4) and the central portion (50) of the "Z"-shaped connecting strip (5) and to fasten these central portions between the two plates when assembling the slip ring (A) by using a set of fastening elements (60). The fastening set preferably consists of a threaded element having a screw or a threaded rod and a threaded counterpart element such as a nut.

[0047] In the context of the present invention, "outwardly" refers to an axial direction opposite to the stator, and "inwardly" refers to an axial direction close to the stator.

[0048] like Figure 7 The connecting cable (10) shown in the figure is preferably fastened to the cable terminal (11) by a crimping process. Then, the connecting cable (10) with the corresponding cable terminal (11) is positioned on the terminals (4A) and (5A) of the "L"-shaped connecting strip (4) and the "Z"-shaped connecting strip (5), respectively.

[0049] In this way, from the described construction, the circular support (1) receives the stator coil wire (not shown) on one side through the coil terminal (8) positioned in the terminals (4B) and (5B), and on the other side, the circular support (1) receives the connecting cable (10) of a specific phase through the cable terminal (11) positioned on the terminals (4A) and (5A) of the "L"-shaped connecting bar (4) and the "Z"-shaped connecting bar (5), respectively.

[0050] In this slip ring configuration, the connection of the parallel path of the circuit is established only at the panel connection point outside the machine (not shown) to avoid current imbalance between the cables of the same phase. In addition, due to this configuration, the axial space is reduced compared to the traditional connection with three copper rings (which are connected for each phase).

[0051] exist Fig.11 In the alternative construction shown in , the connecting strip (5) used has only a "Z" shape and is arranged along the circumference of the circular support (1) and is axially fastened in the through hole (2) of the circular support (1) in the same manner as described for the preferred construction.

[0052] In a first alternative construction, the coil terminals (5A) and (5B) of the connecting bar (5) are mounted in a staggered manner such that the terminal (5A) extends axially outward relative to the stator axis at the innermost radial position and the subsequent terminal (5A) extends axially outward relative to the stator axis at the outermost radial position.

[0053] exist Fig.12In the second alternative construction shown in , the connecting strips (4) used have only an "L" shape and are arranged in alternating positions along the circumference of the circular support (1) and are axially fastened in the through holes (2) of the circular support (1) in the same manner as described for the preferred construction.

[0054] In a second alternative configuration, the coil terminals (4B) of the connecting bar (4) are mounted in a staggered manner so that the first terminal (4B) extends axially outward relative to the stator axis, while the subsequent terminal (4B) extends axially inward relative to the stator axis. In this configuration, the terminals (4A) extend radially outward from the circumference of the circular support (1) at all locations.

[0055] The present invention also includes a manufacturing and assembly method, wherein step a) refers to machining or molding at least two insulating material plates (1A) and (1B), at least two plates each comprising a plurality of through holes (2) and protrusions (9) identically provided with through holes (3), wherein the front plate (1A) is perforated along its circumference to form holes (20), and the rear plate (1B) is molded or machined to produce a recess (30) comprising holes (25) arranged along the circumference of the plate, wherein the holes (25) in the recess are concentric with the holes (20) in the front plate (1A).

[0056] With regard to the manufacture and assembly of step a), it is important to emphasize that the circular support (1) can be made by a machining operation (cutting) of a sheet of insulating material, or preferably by molding fiberglass to form a slip ring (A) with at least two connecting plates (1A) and (1B).

[0057] In step b), at least two insulating material plates (1A) and (1B) are assembled, wherein each recess (30) provides sufficient space to accommodate the central portion (40) of the "L"-shaped connecting strip (4) and the central portion (50) of the "Z"-shaped connecting strip (5).

[0058] In step c), a plurality of "L"-shaped connecting strips (4) and "Z"-shaped connecting strips are fastened in a staggered manner along the circumference of the plates between the two insulating material plates (1A) and (1B). The fastening of the connecting strips (4) and (5) is achieved by a set of reversible fastening elements (60) housed in a through hole (2) formed by concentrically connecting a hole (20) in the front plate (1A) and a hole (25) in the rear plate (1B).

[0059] In step d), the entire assembly forming the slip ring (A) is fastened against the stator core (7) by reversible fastening elements (6) through the holes (3) of the protrusions (9) of the circular support (1).

[0060] In a final step e), the stator coil wires are fastened against the circular support (1) via coil terminals (8) positioned in terminals (4B) and (5B), and on the opposite side, the circular support (1) receives the connection cables (10) of a particular phase via cable terminals (11) positioned on terminals (5A) and (4A) of the "L"-shaped connecting strip (4) and the "Z"-shaped connecting strip (5), respectively.

[0061] The invention also relates to a rotating electrical machine in which a slip ring (A) is fastened to a stator core (7) by a reversible fastening element (6) through a hole (3) of a protrusion (9) of a circular support (1), so that a cable can be connected compactly, such as Figure 7 Indicated in .

[0062] In this way, it is clear that the absence of a welded connection also facilitates the disassembly process, since it is simply the reverse process as described above. That is, the invention allows the cable to be removed by simply disconnecting it from the cable terminal (11), without the need to release the entire ring and coil terminal.

[0063] A person skilled in the art will appreciate the knowledge presented herein and will be able to reproduce the invention in the embodiments and other variations included within the scope of the appended claims.

Claims

1. A slip ring (A), the slip ring being used for a motor stator, characterized in that: The slip ring (A) comprises: A circular support (1), the circular support (1) being formed by a set of insulating plates (1A, 1B); the circular support (1) comprising through holes (2) arranged along its circumference and a plurality of protrusions (9) arranged radially outwardly relative to the center of the connecting ring (A), wherein the protrusions (9) comprise holes (3) for receiving reversible fastening elements (6); A plurality of "L"-shaped connecting strips (4) and "Z"-shaped connecting strips (5), wherein the plurality of "L"-shaped connecting strips (4) and "Z"-shaped connecting strips (5) are arranged in a staggered manner along the circular support member (1), wherein the "L"-shaped connecting strips (4) and "Z"-shaped connecting strips (5) include connection points (4B, 5B) for coil terminals and connection points (4A, 5A) for connecting cables.

2. The slip ring (A) according to claim 1, characterized in that: The circular support (1) is formed by a set of insulating plates (1A, 1B), wherein at least one rear plate (1B) has a plurality of recesses (30) for accommodating the "L"-shaped connecting strips (4) and the "Z"-shaped connecting strips (5).

3. The slip ring (A) according to claim 1 and 2, characterized in that The circular support (1) is positioned a distance "H" of at least 100 mm away from the end of the coil head of the stator.

4. The slip ring (A) according to claims 1 and 2, characterized in that The dimension "R" formed between the innermost surface of the connecting strips (4, 5) and the outer diameter of the rotor (12) is at least 15 mm.

5. The slip ring (A) according to claim 1, characterized in that: Each through hole (2) is positioned at a distance (D) of at least 50 mm relative to the adjacent through hole (2) along the circumference of the circular support (1).

6. The slip ring (A) according to claim 1, characterized in that: Each "L"-shaped connecting strip (4) is arranged between the set of insulating plates (1A, 1B), wherein the terminal (4A) extends radially outward from the circumference of the circular support (1), and the terminal (4B) extends axially inward relative to the stator axis.

7. The slip ring (A) according to claim 1, characterized in that: Each "Z"-shaped connecting bar (5) is arranged between the set of insulating plates (1A, 1B), wherein the terminal (5A) extends axially outward from the circumference of the circular support (1), and the terminal (5B) extends axially inward relative to the stator axis.

8. The slip ring (A) according to claim 1, characterized in that: The connecting cable (10) is fastened to the cable terminal (11) and positioned at the connection point (4A, 5A) of the "L"-shaped connecting bar (4) and the "Z"-shaped connecting bar (5), and the stator coil wire is fastened to the coil terminal (8) positioned on the terminals (4B, 5B) of the "L"-shaped connecting bar (4) and the "Z"-shaped connecting bar (5).

9. A rotating electrical machine, characterized in that: The rotating electrical machine comprises a slip ring (A) as defined in claims 1 to 8, which is fastened to a stator core (7) by means of a reversible fastening element (6).

10. A method for manufacturing and assembling a slip ring (A), characterized in that The method comprises the following steps: a) machining or molding at least two insulating material plates (1A, 1B), both of which include a plurality of through holes (2) and protrusions (9) also provided with through holes (3), wherein the front plate (1A) is perforated along its circumference to form holes (20), and the rear plate (1B) has a recess (30) along its circumference, in which holes (25) are arranged, wherein the holes (25) of the recess are concentric with the holes (20) of the front plate (1A), thereby forming the through holes (2); b) assembling at least two insulating material plates (1A, 1B), wherein each recess (30) provides sufficient space to accommodate the central portion (40) of the "L"-shaped connecting strip (4) and the central portion (50) of the "Z"-shaped connecting strip (5); c) using the through holes (2) to fasten a plurality of "L"-shaped connecting strips (4) and "Z"-shaped connecting strips between the two insulating material sheets in a staggered manner along the circumference of the at least two insulating material sheets through a set of reversible fastening elements (60); d) fastening the entire assembly forming the slip ring against the stator core (7) by means of a reversible fastening element (6) passing through the hole (3) of the protrusion (9) of the circular support (1); e) fastening the stator coil wire against the circular support (1) by means of coil terminals (8) positioned in the terminals (4B, 5B), and on the opposite side, fastening the connection cable (10) of a particular phase by means of cable terminals (11) positioned on the terminals (4A, 5A) of the "L"-shaped connecting strip (4) and the "Z"-shaped connecting strip (5), respectively.

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