Coil support for a rotary electric motor - Patent application

Abstract

To provide a coil support for a rotary electric motor.SOLUTION: There is provided a coil support (10) for a preformed flat coil (30) of a stator of an electric rotary motor. The coil support (10) includes an annular support structure (12), and a plurality of columns (24a, 24b) extending upward from the support structure (12) and separated from each other to form a plurality of corresponding coil receiving portions (22) to hold the coil in place prior to the potting operation. Each of the coil receiving portions (22) is configured to support the lower part of the preformed flat coil (40).SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a coil support for a rotary electric motor, and to a rotary electric motor equipped with such a coil support. [Background technology]

[0002]

[0002] The performance of an electric motor is affected by the positioning of the coils. Therefore, accurate positioning of the coils relative to each other and relative to the coil support is of paramount importance. Furthermore, it is desirable to provide an electric motor with a reduced footprint while minimizing the impact on the motor's magnetic performance. However, for safety reasons, regulatory standards require a minimum creepage distance along the surface of a solid insulating material between two conductive parts, which can be difficult to achieve in very confined spaces.

[0003]

[0003] Coils are typically inserted onto the stator teeth using spacers to ensure that the coils are vertically centered with respect to their corresponding teeth during the assembly process of the electric motor prior to the potting operation, which consists in injecting a synthetic resin to firmly secure all components of the stator, particularly the coils, together, as disclosed, for example, in EP 2 717 434. However, the use of such spacers is time consuming and expensive. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] EP2717434 Summary of the Invention [Problem to be solved by the invention]

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a coil support that is easy to manufacture and that reduces the overall cost of a rotary electric motor by integrating several functions.

[0006] Another object of the present invention is to provide a coil support that increases the ratio of motor magnetic performance to motor footprint. It is a further object of the present invention to provide a coil support which allows the coil to be easily positioned and adhered onto the support prior to the potting operation. [Means for solving the problem]

[0007] These objects are achieved by a coil support for a preformed flat coil of a stator of an electric rotary motor. The coil support includes an annular support structure and a plurality of spaced columns extending upwardly from the support structure to form a corresponding plurality of coil-receiving portions for holding the preformed flat coil in place prior to a potting operation. Each of the coil-receiving portions is configured to support a lower portion of the preformed flat coil.

[0008] In one embodiment, the lower portion of the preformed flat coil corresponds to approximately half of the overall height of the preformed flat coil.

[0009] In one embodiment, the plurality of columns includes first and second groups of columns, wherein a narrowest width of the columns in the first group is greater than a narrowest width of the columns in the second group, and one or more adjacent columns in the second group are disposed between two columns in the first group.

[0009]

[0010] In one embodiment, the coil support is suitable for a three-phase rotary motor, where the narrowest width of the first group of columns is at least 3 mm to ensure a minimum gap of 3 mm between adjacent coils that are to be wired to different phases of the motor, and the narrowest width of the second group of columns is less than 1.5 mm, preferably less than 1 mm, to reduce the distance between adjacent coils that are to be wired to the same phase of the motor.

[0010]

[0011] In one embodiment, the upper portion of each column includes a groove of a predetermined shape, preferably a T-shaped groove having a first groove portion extending between two coils when the coils are mounted on the coil support and a second groove portion extending radially outward from the first groove portion.

[0011]

[0012] In one embodiment, the bottom side of the annular support structure comprises a medial annular flat surface from which a number of studs protrude.

[0013] In one embodiment, the bottom side of the annular support structure further comprises outer and inner angled annular surfaces adjacent each side of the intermediate annular flat surface.

[0012]

[0014] In one embodiment, the coil support further comprises first and second pluralities of insulating sheet supports extending radially outward from the annular support structure, the first pluralities of insulating sheet supports extending radially further than the second pluralities of insulating sheet supports, and each of the first pluralities of insulating sheet supports is disposed between two of the second pluralities of insulating sheet supports such that the cylindrical insulating sheet has a corrugated shape when attached to the first and second pluralities of insulating sheet supports.

[0013]

[0015] In one embodiment, each column includes a side surface and a shoulder extending substantially perpendicular to the rearward portion of the side surface of each column.

[0016] Another aspect of the invention relates to a coil assembly comprising the coil support described above and a plurality of preformed flat coils in their respective coil-receiving portions, the rear portion of each preformed flat coil resting against the shoulders of two adjacent columns, the coils being glued in place using a small amount of liquid instant adhesive placed in a groove on the upper portion of each column.

[0014]

[0017] Another aspect of the present invention relates to a stator for a rotary electric motor comprising a stator housing having a cylindrical inner wall, the above-described coil assembly mounted inside the cylindrical inner wall, and a corrugated insulating sheet mounted between the inner wall of the stator housing and the coil assembly.

[0015]

[0018] A further aspect of the present invention relates to a rotary electric motor including a stator as described above.

[0019] The invention will be better understood from the description of some embodiments given by way of example and illustrated in the drawings. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 10 is a top perspective view of a coil support according to one embodiment of the present invention. [Figure 2] FIG. 2 is a bottom perspective view of the coil support of FIG. 1. [Figure 3] 2 is a partial perspective view of the coil support of FIG. 1 showing the coil receiving portion. [Figure 4] 2 is a perspective view of the coil support of FIG. 1 with a preformed flat coil attached. [Figure 5] FIG. 5 is a partial top view of FIG. [Figure 6] 2 is a perspective view of a stator of a rotary electric motor including the coil support of FIG. 1 with preformed flat coils attached thereto; FIG. [Figure 7] FIG. 7 is a top view of FIG. [Figure 8] FIG. 8 is a partial top view of FIG. [Figure 9]FIG. 9 is a detailed view of FIG. 8 showing the preformed coil mounted inside the coil-receiving portion of the coil support. [Figure 10] FIG. 7 is a cross-sectional perspective view of FIG. 6. [Figure 11] FIG. 7 is a partial perspective view of FIG. 6. DETAILED DESCRIPTION OF THE INVENTION

[0017]

[0020] Referring to FIG. 1, coil support 10 is suitable for a three-phase rotary motor. In this regard, coil support 10 includes an annular support structure 12 and a plurality of spaced-apart columns 24a, 24b extending upwardly from support structure 12. As particularly shown in FIG. 3, the widths d1, d2 of each column 24a, 24b vary along its upward direction to form a corresponding plurality of coil-receiving portions 22 having substantially U-shaped receiving portions. Each column 24a, 24b includes a side surface 28 and a back surface extending substantially perpendicular to side surface 28 to form a shoulder 30. The unique configuration of these columns allows for precise adjustment of a coil 40 on coil support 10 by pressing the back surface of the coil against shoulder 30 of columns 24a, 24b, as can be seen, for example, in FIGS. 4 and 5.

[0018]

[0021] The coils 40 are of the type of preformed flat coil that can be easily made, thus reducing their manufacturing costs, as opposed to preformed bent coils that require an additional bending step, which sometimes has the disadvantage of making the manufacturing costs higher by damaging or generating scrap in the wire insulation. The preformed flat coils 40 are positioned from the top of the coil supports 10 into their respective U-shaped receiving portions, which are designed to support and accurately position the lower portions of the preformed flat coils, which correspond to roughly half of the total height of the coils.

[0019]

[0022] The multiple columns 24a, 24b of the coil support 10 are divided into a first group of columns 24a of the same shape and a second group of columns 24b of the same shape but different from the shape of the first group of columns 24a. More specifically, as shown in FIG. 3, the narrowest width d1 of the columns 24a in the first group is greater than the narrowest width d2 of the columns 24b in the second group.

[0020]

[0023] According to this exemplary embodiment of the coil support 10, the first group of columns includes six columns 24a, and the second group of columns includes twelve columns 24b. Two adjacent columns 24b in the second group are attached between each pair of two columns 24a in the first group of six columns 24a. The number of columns in the first and second groups can vary depending on the size and number of pre-formed flat coils of the electric motor that need to be supported and precisely positioned. The coil support 10 is designed to have an optimal ratio between the motor's magnetic performance and the motor's footprint.

[0021]

[0024] As shown in FIG. 4, a corresponding plurality of preformed flat coils 40 are positioned within respective coil-receiving portions 22 of the coil support 10 to provide a compact coil assembly 32. The preformed flat coils are mounted in groups according to their phase connections. More specifically, with reference to FIG. 7, a first pair of groups of three adjacent first phase coils 40a are mounted diametrically opposed in the coil-receiving portion 22 of the coil support 10 (FIG. 1), a second pair of groups of three adjacent second phase coils 40b are mounted in the coil-receiving portion of the coil support adjacent to the first pair of first phase coils 40a, and a third pair of groups of three adjacent third phase coils 40c are mounted in the coil-receiving portion of the coil support adjacent to the second pair of second phase coils 40b.

[0022]

[0025] Each pair of adjacent first, second, and third phase coils 40a, 40b, and 40c coils is configured to be wired together and electrically connected to a respective phase of a three-phase rotary motor. The voltages of adjacent coils of the same phase are similar, and therefore the coils can be placed close to each other to maximize the copper space factor and, thereby, the magnetic performance of the electric motor.

[0023]

[0026] Thus, referring to FIG. 3, the narrowest width d2 of the second group of columns 24b can be less than 1.5 mm, preferably less than 1 mm, to reduce the distance between adjacent coils that are to be wired to the same phase of the electric motor. For adjacent coils of different phases, regulatory safety standards require a minimum creepage distance of 3 mm to avoid leakage currents that could result in electric motor failure. Therefore, the narrowest width d1 of column 24a is approximately 3 mm. Thus, columns 24a, 24b are designed to optimize the ratio between the motor's performance and its footprint while complying with regulatory safety standards.

[0024]

[0027] Referring to FIG. 9, when the coils are attached to the coil support 10 and the coil support 10 is attached to the inside of the stator housing 50 with the insulating sheet 45 disposed between the inner wall 52 of the stator housing 50 and the coil support 10, an electrical connection space 35 for the input wire of the corresponding coil is created between the inside 52 of the insulating sheet 45 and the back surface of the corresponding coil.

[0025]

[0028] 8 and 11, the upper portion of each column 24a, 24b includes a predetermined groove, such as a substantially T-shaped groove 26 having a first groove portion 26a that opens into both adjacent coil-receiving portions 22 and a second groove portion 26b that extends radially outward from the first groove portion 26a. The T-shaped groove 26 of each column 24a, 24b is designed to receive a liquid instant adhesive and - flowing into the gap between one side of each adjacent coil and both sides 28 of the respective column to secure the coils to the coil support 10; Also, - in contact with the insulating sheet 45 to secure the insulating sheet 45 to the coil assembly 32 comprising the coil and the coil support; It is designed to guide such adhesives.

[0026]

[0029] The operator adheres one coil at a time into its respective U-shaped receiving portion 22 by depositing a small amount of liquid instant adhesive into the groove 26 in the upper portion of the corresponding column 24a, 24b while maintaining the coil pressed against the shoulders 30 of two adjacent columns forming the U-shaped receiving portion.

[0027]

[0030] Referring to FIG. 2, the bottom side of the annular support structure 12 includes a middle annular flat surface 14 and several studs 15 protruding from the middle annular flat surface 14. The bottom side of the annular support structure 12 further includes outer and inner inclined annular surfaces 16, 18 adjacent to the middle annular flat surface 14. The studs 15 are configured to rest on the bottom surface of the stator housing 50. This creates a gap between the bottom side of the coil support 10 and the bottom surface of the stator housing to ensure that the synthetic resin fills the gap during the potting operation. The inclined annular surfaces 16, 18 of the coil support 10 prevent the formation of air bubbles during the potting operation.

[0028]

[0031] 2 and 5, the coil support 10 further includes first and second insulating sheet supports 20a, 20b extending radially outward from the annular support structure 12. The first insulating sheet supports 20a extend radially farther than the second insulating sheet supports 20b. Each of the first insulating sheet supports 20a is disposed between two insulating sheet supports 20b of the second insulating sheet supports. The distal end of each insulating sheet support includes an upwardly extending portion 20c (FIG. 10) to form a groove. An insulating sheet 45 is inserted into each groove to create the corrugated or undulating circular shape of the insulating sheet 45, thereby creating a space with the inner wall 52 of the stator housing 50 to allow for the removal of air bubbles that may occur during the potting process to achieve optimal insulation.

[0029]

[0032] As described above, the insulating sheet 45 is attached to the coil support 10 prior to the gluing operation so that as the operator successively fills the T-shaped grooves 26 of each column 24a, 24b of the coil support 10 with liquid instant adhesive, the liquid instant adhesive flows along the second groove portion 26b (FIG. 11) and contacts the insulating sheet 45, securing it to the coil support.

[0030]

[0033] 5 and 10, the insulating sheet support 20b prevents the lower end of the insulating sheet 45 from contacting the bottom surface of the stator housing 50. Therefore, the synthetic resin can completely flow into the gaps of the stator during the potting operation, thereby ensuring insulation between all conductive parts of the stator.

[0031]

[0034] The electrical connection space 35 can be advantageously used for electrical wire output from the center of the coil and for making connections between the coils prior to the potting operation.

[0035] The coil support is advantageously fabricated by an additive manufacturing process, which reduces the overall manufacturing cost of the electric motor. In that regard, the side surfaces 28 of each column 24a, 24b slope outward, and the inner diameter increases continuously upward. This configuration ensures that the narrowest width of the columns is 1 mm or greater, making them compatible with additive manufacturing. [Explanation of symbols]

[0032] 10 Coil support 12 Annular support structure 14 Intermediate annular flat surface 15 studs 16 External beveled annular surface 18 inner annular surface 20 Insulation sheet support 20a First radially extending portion 20b Second radially extending portion 20c: Part that curves upward, part that extends upward 22 Coil receiving section 24a First Column Group 24b Second column group 26 T-shaped groove 26a First groove portion 26b Second groove portion 28 Side 30 Shoulder 32 Coil assembly 35 Electrical connection space 40 Preformed flat coil 40a 1st phase coil 40b Second phase coil 40c Third phase coil 45 Insulation sheet 50 stator housing 52 Inner wall

Claims

1. A coil support (10) for a preformed flat coil (30) of a stator of an electric rotary motor, comprising: an annular support structure (12); and a plurality of columns (24a, 24b) extending upwardly from the support structure (12) and spaced apart from one another to form a corresponding plurality of coil receiving portions (22) for holding the preformed flat coil in place prior to a potting operation, each of the coil receiving portions (22) configured to support a lower portion of a preformed flat coil (40); the plurality of columns includes a first and a second group of columns (24a, 24b), wherein a narrowest width (d1) of the columns (24a) of the first group is greater than a narrowest width (d2) of the columns (24b) of the second group, and one or more adjacent columns (24b) of the second group are disposed between two columns (24a) of the first group; The coil support (10) is suitable for a three-phase rotary motor, and the narrowest width (d1) of the columns (24a) of the first group is at least 3 mm to ensure a minimum gap of 3 mm between adjacent coils (40a, 40b, 40c) to be connected to different phases of the motor, and the narrowest width (d2) of the columns (24b) of the second group is less than 1.5 mm, preferably less than 1 mm, to reduce the distance between adjacent coils to be connected to the same phase of the motor.

2. 2. A coil support (10) according to claim 1, A coil support (10) whose lower portion corresponds approximately to half the total height of the preformed flat coil (40). Coil support (10).

3. A coil support (10) according to claim 1 or 2, A coil support (10) in which the upper portion of each column (24a, 24b) is provided with a groove (26) of a predetermined shape, preferably a T-shaped groove, including a first groove portion (26a) extending between two coils when the coils are attached to the coil support (10) and a second groove portion (26b) extending radially outward from the first groove portion.

4. A coil support (10) according to any one of claims 1 to 3, A coil support (10) in which the bottom side of the annular support structure (12) comprises an intermediate annular flat surface (14) from which several studs (15) protrude.

5. A coil support (10) according to claim 4, The coil support (10) further comprises outer and inner inclined annular surfaces (16, 18) adjacent to each side of the intermediate annular flat surface (14), the bottom side of the annular support structure (12).

6. A coil support (10) according to any one of claims 1 to 5, The coil support (10) further comprises first and second pluralities of insulating sheet supports (20a, 20b) extending radially outward from the annular support structure (12), wherein the first pluralities of insulating sheet supports (20a) extend radially further than the second pluralities of insulating sheet supports (20b), and each of the first pluralities of insulating sheet supports (20a) is disposed between two of the second pluralities of insulating sheet supports (20b) such that the first pluralities of insulating sheet supports have a corrugated shape when a circular insulating sheet (45) is attached to the first and second pluralities of insulating sheet supports (20a, 20b).

7. A coil support (10) according to any one of claims 1 to 6, A coil support (10) in which each column (24a, 24b) comprises a side surface (28) and a shoulder (30) extending substantially perpendicular to a rear portion of said side surface (28).

8. A coil assembly (32) comprising the coil support (10) of claim 7 and a plurality of preformed flat coils (40) in their respective coil receiving portions, wherein a rear portion of each preformed flat coil (40) rests against the shoulders (30) of two adjacent columns.

9. 10. A stator for a rotary electric motor, comprising: a stator housing (50) having a cylindrical inner wall (52); a coil assembly (32) according to claim 8 attached to the inside of said cylindrical inner wall (52); and a corrugated insulating sheet (45) attached between said inner wall (52) and said coil assembly (32).

10. A rotary electric motor comprising the stator of claim 9.

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