Stator winding connection arrangement for electric motor

[0002] 1. Field of the Invention

[0003] The present invention relates to an electric motor incorporated in a compressor or the like mounted on an air conditioner or the like, and more particularly, it relates to an attachment structure of a lead wire drawn out of a stator winding.

[0004] 2. Background Art

[0005] As shown in FIG. 11, an electric motor 1aincorporated in a compressor 1 mounted on an air conditioner or the like is constituted of a rotor 3 fixed to a rotation shaft 2, and a stator 4 disposed on an outer peripheral side of the rotor 3 via a small gap.

[0006] A top plan view of the stator 4 is shown in FIG. 12. The stator 4 is constituted of a stator core 5 having a plurality of (six in the drawing) magnetic pole teeth disposed in a peripheral direction at a predetermined interval so as to project toward a central portion (the rotor), and stator windings 7ato 7fwound around the respective magnetic pole teeth of the stator core 5 via insulating members 6. In an end surface portion of the stator core 5, a plurality of winding terminal receiving portions 8ato 8fare disposed integrally with the insulating members 6. These winding terminal receiving portions 8ato 8fare dispersedly disposed on the end surface portion of the stator core 5 in the peripheral direction to accept winding ends of the respective stator windings 7ato 7fclosely disposed.

[0007] The stator windings 7ato 7fare connected to a power source via a lead wire unit 11. The lead wire unit 11 is constituted of lead wires 13ato 13f, winding side connection fittings 12 (FIG. 13) electrically connected to respective one ends of the wires and attached to the winding terminal receiving portions 8ato 8f, and a power source connector 14 disposed on the other end of the lead wire.

[0008] In general, attaching of terminal portions of the respective stator windings to the winding terminal receiving portions 8ato 8fand inserting/fixing of the connection portion 12 can be automated. In the attaching of the lead wire unit 11, however, for example, with a three-phase motor, two for each phase, that is, six winding terminals 9ato 9fin total are present, and six connection fittings 12 and six lead wires 13ato 13fare therefore necessary. Therefore, manufacturing cost of the lead wire unit 11 is raised, further a large number of processes are necessary for attaching the unit, and from this aspect, cost also increases.

[0009] Moreover, for the conventional connection fitting 12, while the lead wires 13ato 13fare inserted into lower cutouts of the connection fittings 12 in a radial direction, the connection fitting 12 is pressed downward to break insulation of the lead wire and electrically connect the connection fitting 12 to the lead wire. In this case, the lead wires 13ato 13fturned in the radial directions to be inserted into the connection fittings 12 are led around in the peripheral direction and connected to the power source connector 14, and therefore flexing forces act on the lead wires 13ato 13fin the connection fittings 12. Therefore, when an external force is further applied to the lead wires 13ato 13fand the connection fittings 12, there is a possibility that disconnection and connection defect occur with the lead wire.

[0010] In order to avoid the aforementioned disadvantage, as shown in FIG. 14, the flexing force is prevented from acting on the lead wire. Winding terminal receiving portions 16 for a three-phase motor are collectively disposed in one place on the end surface of the stator core 5, the winding terminal is attached in a vertical direction to a connection terminal 15 disposed in the winding terminal receiving portion 16, and further a bifurcated terminal conductor 18adisposed on a terminal plate 17 is pressed from above and inserted into the connection terminal 15 to put the winding terminal between leg portions, so that the winding terminal is electrically connected to the terminal conductor 18a. The other end of the terminal conductor 18awhose one end is vertically inserted into the connection terminal 15 is bent as a terminal conductor 18bat right angles in the terminal plate 17 and extended to the outside in the radial direction. A casing 19 is formed to surround the terminal conductor 18b. The terminal conductor 18band casing 19 are joined to a winding end side connection portion 11aof the lead wire unit 11 to constitute a connection terminal for electric connection.

[0011] A connection structure of FIG. 14 can solve a problem of flexing force exerted on the lead wire in FIGS. 12 and 13, but it is necessary to lead a far detached winding terminal along the insulating member 6 to the winding terminal receiving portion 16. Therefore, a winder structure for performing this operation becomes complicated. Furthermore, in this case, the terminal plate 17 needs to be integrally molded with a terminal 18 by a resin mold, and this is one factor to cause cost increase.

[0012] The present invention has been developed in consideration of the aforementioned circumstances, and an object thereof is to provide a highly reliable motor in which to attach a lead wire unit to the motor, the number of operation processes can be reduced to achieve cost decrease, and further a damage associated with leading of a lead wire does not easily occur.

[0013] To achieve the aforementioned object, according to one embodiment of the present invention, there is provided a motor comprising a plurality of windings wound around a stator core; a plurality of winding terminal receiving portions, disposed on an end surface portion of the stator core at an interval in a peripheral direction, for individually receiving a plurality of winding terminal portions; a plurality of first conductive connection fittings, attached to said respective winding terminal receiving portions, for fixing said winding terminal portions to said winding terminal receiving portions and for electrically connecting with said winding terminal portions; a plurality of second conductive connection fittings whose one surface side is provided with a projection for contacting said first connection fitting and whose other surface side is provided with a lead wire which is electrically connected to said winding terminal portion and which extends through the second conductive connection fittings in the peripheral direction of said stator core; and a terminal plate having connection fitting receiving portions to which said plurality of second connection fittings are attached and which are dispersed in the peripheral direction so as to correspond to said plurality of winding terminal receiving portions.

[0014] According to another embodiment, there is provided a motor comprising a plurality of windings wound around a stator core; a plurality of winding terminal receiving portions, disposed on an end surface portion of said stator core at an interval in a peripheral direction, for individually receiving a plurality of winding terminal portions; a plurality of connection fittings which fixes said winding terminal portion to said winding terminal receiving portion and which electrically connects with said winding terminal portion on one side, said plurality of connection fittings having a groove through which a lead wire connected to said winding terminal portion passes in the peripheral direction of said stator core on the other side; and a terminal plate having connection fitting receiving portions to which said plurality of connection fittings are attached and which are dispersed in the peripheral direction so as to correspond to said plurality of winding terminal receiving portions; said connection fitting being beforehand attached to either of said winding terminal receiving portion and said terminal plate. According to this embodiment, since the number of materials or the number of components can be reduced, the number of processes and cost can further be reduced.

[0015] The winding terminal portion may be drawn in a radial direction of a stator and fixed to the first connection fitting. This can prevent a flexing force from acting on the lead wire in a lead wire connection portion.

[0016] The connection fitting may be attached to constitute a pressure contact type terminal for breaking an insulation coat of the winding or the lead wire disposed beforehand for electrically conductive contact. This can simplify an assembly operation.

[0017] The terminal plate is provided with a guide groove for guiding the lead wire, and this guide groove may have a width substantially equivalent to a diameter of the lead wire, and also have a depth such that a plurality of lead wires can be superposed and accommodated. This can prevent the lead wires from jumping out or crossing one another when the wires are led around.

[0018] FIG. 1 is a top plan view of a stator according to a first embodiment of the present invention,

[0019] FIG. 2 is a perspective view showing a first connection fitting in FIG. 1,

[0020] FIG. 3 is an enlarged perspective view of a winding terminal receiving portion in FIG. 1,

[0021] FIG. 4 is a perspective view of a terminal plate to be assembled with a stator of FIG. 1,

[0022] FIG. 5 is a sectional view of the terminal plate of FIG. 4,

[0023] FIG. 6 is a diagram showing that a lead wire unit is attached to the terminal plate of FIG. 4,

[0024] FIG. 7 is a perspective view of a second connection fitting to be assembled with the stator of FIG. 1,

[0025] FIG. 8 is a diagram showing that the terminal plate of FIG. 5 is attached to the stator of FIG. 1,

[0026] FIG. 9 is a perspective view of a connection fitting according to a second embodiment of the present invention,

[0027] FIG. 10 is a perspective view showing that the connection fitting of FIG. 9 is inserted into the winding terminal receiving portion,

[0028] FIG. 11 is a schematic sectional view of a known compressor to which the present invention is applied,

[0029] FIG. 12 is a top plan view of a conventional motor stator,

[0030] FIG. 13 is a perspective view of the connection fitting in FIG. 12, and

[0031] FIG. 14 is an explanatory view showing a conventional lead wire attachment structure in which winding terminal receiving portions are collectively disposed.

[0032] An embodiment of the present invention will be described hereinafter in detail with reference to the drawings.

[0033] FIG. 1 shows a first embodiment of an electric motor according to the present invention. This embodiment relates to a stator 4 of a motor 1aincorporated in a compressor 1 mounted on an air conditioner as shown in FIG. 11.

[0034] As shown in FIG. 1, the stator 4 is constituted of a stator core 5 having a plurality of (six in a shown case) magnetic pole teeth disposed in a peripheral direction with a predetermined interval to jut out toward a central portion (rotor), and stator windings 7ato 7fwound around the respective magnetic pole teeth of the stator core 5 via insulating members 6. In a top end surface portion of the stator core 5, a plurality of winding terminal receiving portions 8ato 8fare disposed integrally with the insulating members 6. These winding terminal receiving portions 8ato 8fare dispersed and disposed on the end surface portion of the stator core 5 in the peripheral direction to accept winding ends of the respective stator windings 7ato 7fdisposed in the vicinity.

[0035] The winding 7aand the winding 7dpositioned opposite to the winding are continuously wound around to constitute a first phase winding, similarly the windings 7band 7eare continuously wound around to constitute a second phase winding, and further the windings 7cand 7fare continuously wound around to constitute a third phase winding. A winding terminal 9adrawn from the winding 7ais attached as a winding start end of the first phase winding to the winding terminal receiving portion 8a, and a winding terminal 9ddrawn from the winding 7dis attached as a winding finish end of the first phase winding to the winding terminal receiving portion 8d. Similarly, a winding terminal 9cdrawn from the winding 7cis attached as a winding start end of the second phase winding to the winding terminal receiving portion 8c, and a winding terminal 9fdrawn from the winding 7fis attached as a winding finish end of the second phase winding to the winding terminal receiving portion 8f. Furthermore, a winding terminal 9edrawn from the winding 7eis attached as a winding start end of the third phase winding to the winding terminal receiving portion 8e, and a winding terminal 9bdrawn from the winding 7bis attached as a winding finish end of the third phase winding to the winding terminal receiving portion 8b. The stator windings 7aand 7d, 7band 7e, and 7cand 7fin positions mechanically deviating from each other by 180° are continuously wound around, and portions corresponding to middles are connected in common to form a three-phase system neutral point. After attaching the winding terminals 9ato 9fto the respective winding terminal receiving portions 8ato 8f, a conductive first connection fitting 10 for fixing the winding terminal (see FIGS. 2, 3) is inserted thereinto.

[0036] As shown in FIG. 2, for the first connection fitting 10, one flat metal plate is bent substantially in a U shape and processed to obtain a size such that the fitting can be inserted into the winding terminal receiving portions 8ato 8f, and a cutout 20 slightly narrower than a diameter of the stator windings 7ato 7f(hereinafter referred to as the winding 10) is formed along a height from a bottom to a middle of the U-shaped metal plate. One tip end portion of the U-shaped metal plate is turned back toward the other tip end portion to form an engaging piece 10afor engaging with a lead wire unit connection terminal described later, and a plurality of projections 10bfor engaging with inner walls of the winding terminal receiving portions 8ato 8fare formed in a side surface of the plate.

[0037] As shown in FIG. 3, after inserting a winding terminal 9 (generic numeral of 9ato 9f) into a winding terminal receiving portion 8 (generic numeral of 8ato 8f) to the outside from the inside, and by inserting the first connection fitting 10 into the winding terminal receiving portion 8 in such a manner that the cutout, that is, groove 20 holds the winding terminal, the groove 20 breaks a winding insulating coating film, and the first connection fitting 10 is electrically and mechanically connected to the winding terminal 9. This connection system is known as a “pressure contact type terminal”.

[0038] A terminal plate 21 disposed on the top end surface of the stator core 5 will next be described. As shown in FIG. 4, the terminal plate 21 is formed in an annular shape to be held in the top end surface of the stator core 5, and is provided with a guide groove 22 for leading a lead wire around in the peripheral direction of the stator 4. A width of the guide groove 22 is set to be substantially equal to a diameter of a lead wire 23 (see FIG. 5). A depth of the guide groove 22 is set to be twice or more as large as the diameter of the lead wire such that two or more lead wires 23 are superposed and accommodated as shown in FIG. 5. During leading around of the lead wire 23, the lead wire 23 is pushed into the guide groove 22 and led around along the guide groove 22. Thereby, the lead wire 23 is fixed, and an operation of leading around the lead wire is facilitated.

[0039] In the terminal plate 21, connection fitting receiving portions 25ato 25ffor containing a second conductive connection metal 24 (see FIG. 7) along the guide groove 22 are disposed on an outer peripheral side of the terminal plate 21 and dispersed in the peripheral direction. When the terminal plate 21 is disposed in the stator, the receiving portions 25ato 25fare disposed in positions opposite to the winding terminal receiving portions 8ato 8f(see FIG. 1) formed and disposed integrally with the insulating member 6 on the end surface of the stator core 5.

[0040] For a first phase lead wire 23uattached to the terminal plate 21, as shown in FIG. 6, one terminal thereof is inserted and disposed into the lead wire connection fitting receiving portion 25afrom the peripheral direction, and subsequently a terminal plate side engagement portion 24aof the second connection fitting 24 shown in FIG. 7 is inserted from above and fixed. After leading the lead wire 23usubstantially around the half of a periphery along the guide groove 22 (see FIG. 4, 5) from the connection fitting receiving portion 25a, the lead wire 23uis passed through the connection fitting receiving portion 25dpositioned opposite to the connection fitting receiving portion 25a, and the terminal plate side engagement portion 24aof the second connection fitting 24 is inserted into the connection fitting receiving portion 25dto fix the lead wire 23u. After the lead wire 23uis further drawn out of a lead wire exit 26, the other terminal portion of the wire is connected to a power source connector 27.

[0041] Similarly, for a lead wire 23v, one terminal thereof is disposed in the connection fitting receiving portion 25b, and the terminal plate side engagement portion 24aof the second connection fitting 24 is inserted into the connection fitting receiving portion 25bto engage with the terminal of the lead wire 23v, and fixed. After leading the lead wire 23vsubstantially around the half of the periphery along the guide groove 22 from the connection fitting receiving portion 25b, the lead wire 23vis passed through the connection fitting receiving portion 25epositioned opposite to the connection fitting receiving portion 25b, and the terminal plate side engagement portion 24aof the second connection fitting 24 is inserted into the connection fitting receiving portion 25e. After the lead wire 23vis drawn out of the lead wire exit 26, the other lead wire terminal is connected to the power source connector 27.

[0042] Also for a lead wire 23w, one terminal thereof is disposed in the connection fitting receiving portion 25f, and the terminal plate side engagement portion 24aof the second connection fitting 24 is inserted into the connection fitting receiving portion 25fto engage with the terminal of the lead wire 23w, and fixed. Moreover, after leading the lead wire 23wsubstantially around the half of the periphery along the guide groove 22 from the connection fitting receiving portion 25f, the lead wire 23wis passed through the connection fitting receiving portion 25cpositioned opposite to the connection fitting receiving portion 25f, and the terminal plate side engagement portion 24aof the second connection fitting 24 is inserted into the connection fitting receiving portion 25c. After the lead wire is drawn out of the lead wire exit 26, the other terminal of the lead wire 23wis connected to the power source connector 27. The lead wires 23u, 23v, 23wdrawn out of the lead wire exit 26 are twined into one bunch and connected to the power source connector 27.

[0043] Additionally, the second connection fitting 24 shown in FIG. 7 is provided with the terminal plate side engagement portion 24aformed by folding back one end of one metal plate in a rectangular parallelepiped shape to obtain a size such that the portion can be inserted into the lead wire receiving portion 25a. Moreover, in order to electrically connect the terminal plate side engagement portion 24ato the lead wires 23u, 23v, 23w, the portion is provided with a groove portion 28 whose entrance is formed in a tapered shape, and a click 28afor preventing the lead wire from dropping is disposed for the groove portion 28 in the vicinity of the entrance of the groove portion 28. Furthermore, for the second connection fitting 24, the other end of the metal plate is used to form a terminal conductor 29 jutting out in a fork shape, which is inserted into the first connection fitting 10 inserted in the winding terminal receiving portions 8ato 8fto constitute the connection fitting. The terminal conductor 29 is provided with a groove portion 30 for passing the winding terminals 9ato 9ftherethrough when the conductor is inserted into the first connection fitting 10. Additionally, the groove portions 28 and 30 are designed to be in an orthogonal relation such that the lead wire 23 crosses at right angles to the winding terminals 9ato 9f.

[0044] The terminal plate 21 assembled by the aforementioned constitution is disposed on the end surface of the stator core 5 as shown in FIG. 8 by aligning the second connection fitting 24 with the first connection fitting 10, and six projections 29 of the second connection fitting 24 attached to the terminal plate 21 are simultaneously inserted into the engaging pieces 10aof the first connection fittings 10, so that the winding terminals 9ato 9fare connected to the lead wires 23u, 23v, 23w.

[0045] The second connection fitting 24 inserted in the lead wire receiving portion 25ain this manner is connected to the first connection fitting 10 inserted in the winding terminal receiving portion 8a, the second connection fitting 24 inserted in the lead wire receiving portion 25dis connected to the first connection fitting 10 inserted in the winding terminal receiving portion 8d, the second connection fitting 24 inserted in the lead wire receiving portion 25bis connected to the first connection fitting 10 inserted in the winding terminal receiving portion 8b, the second connection fitting 24 inserted in the lead wire receiving portion 25eis connected to the first connection fitting 10 inserted in the winding terminal receiving portion 8e, the second connection fitting 24 inserted in the lead wire receiving portion 25fis connected to the first connection fitting 10 inserted in the winding terminal receiving portion 8f, and the second connection fitting 24 inserted in the lead wire receiving portion 25cis connected to the first connection fitting 10 inserted in the winding terminal receiving portion 8c. That is to say, the lead wire 23uis connected to the winding terminals 9aand 9ddrawn out of the stator windings 7aand 7d, the lead wire 23vis connected to the winding terminals 9band 9edrawn out of the windings 7band 7e, and the lead wire 23wis connected to the winding terminals 9cand 9fdrawn out of the windings 7cand 7f.

[0046] Additionally, in FIG. 8, the power source connector 27, and lead wire 23 formed of the lead wires 23u, 23v, 23wconstitute a lead wire unit 31.

[0047] According to the aforementioned first embodiment, since the terminal plate 21 is disposed on the stator to complete the connection of the winding terminal to the lead wire, an attaching process can be simplified. Moreover, since the lead wire is led around in the peripheral direction of the stator, there is no flexing of the lead wire in the connection fitting, and wiring can be led around without any tensile force. Furthermore, since the terminal plate 21 is provided with the guide groove 22, a lead-out wire is fixedly disposed, the leading-around operation can securely and easily be performed, and the wiring can be prevented from jumping out or crossing.

[0048] A second embodiment of the motor of the present invention will next be described.

[0049] In the second embodiment shown in FIG. 9, a connection fitting 100 is used in which a connection fitting 101 to be connected to the winding terminal 9 is integrally molded with a connection fitting 102 to be connected to the lead wire 23. First, the winding terminal 9 is disposed in the winding terminal receiving portion 8, and subsequently, the connection fitting 100 is inserted/attached into the winding terminal receiving portion 8 as shown in FIG. 10. This fixes the winding terminal 9 to the winding terminal receiving portion 8, and additionally electrically connects the connection fitting 102 to the winding terminal 9. Moreover, the terminal plate 21 in which the lead wire 23 is led around along the guide groove 22 is disposed on the end surface of the stator core 5 with the connection fitting 100 attached thereto, and a plurality of connection fittings 100 are simultaneously inserted and attached into lead wire receiving portions 25 of the terminal plate 21. This realizes electric connection of the lead wire 23 to the connection fitting 100. Thereby, the electric connection of the stator windings 7ato 7fto the lead wire 23 is completed.

[0050] According to the aforementioned second embodiment, an operation (six processes) of inserting the lead wire side connection fittings into the terminal plate becomes unnecessary, the number of processes decreases, and the operation is further simplified as compared with the first embodiment.