Stator, electric motor, and work machine

Abstract

This stator comprises: a cylindrical stator core in which a plurality of slots are formed arranged in the circumferential direction; a stator coil that is inserted into each of the plurality of slots, is wound around the stator core, and has a plurality of terminal-side extension parts that extend outward from a first end surface in the axial direction of the stator core and are arranged in the circumferential direction; and a fixing part that fixes the portions that are adjacent to each other in the circumferential direction in the plurality of terminal-side extension parts.

Description

Stator, electric motor and work machine

[0001] The present disclosure relates to a stator, an electric motor, and a work machine. This invention claims priority to Japanese Patent Application No. 2023-201045, filed on November 28, 2023, the contents of which are incorporated herein by reference.

[0002] Patent Document 1 discloses a configuration including a stator core having slots for inserting windings, each phase winding drawn out to the axial end of the stator core, a neutral wire separate from each phase winding, and fixing means for fixing each phase winding to which the neutral wire is connected and each adjacent phase winding.

[0003] Japanese Patent Application Publication No. 2016-15797

[0004] However, in the configuration of Patent Document 1, the fixing portions of adjacent phase windings are located in recessed positions in the radial direction, which makes it difficult to arrange the fixing means. If the fixing means cannot be arranged appropriately, there is a risk that the fixing strength of each phase winding will be reduced.

[0005] An object of aspects of the present disclosure is to provide a stator, an electric motor, and a work machine that can be easily assembled and have improved fixing strength.

[0006] A stator according to one aspect of the present disclosure comprises a cylindrical stator core having a plurality of slots arranged in a circumferential direction, a stator coil inserted into each of the plurality of slots and wound around the stator core, the stator coil having a plurality of end-side extension portions extending outward from a first axial end face of the stator core and arranged in the circumferential direction, and a fixing portion that fixes adjacent portions of the end-side extension portions to each other in the circumferential direction.

[0007] According to aspects of the present disclosure, it is possible to provide a stator, an electric motor, and a work machine that can achieve improved assembly ease and improved fixing strength.

[0008] 1 is a schematic diagram showing a work machine according to an embodiment; FIG. 2 is a cross-sectional view of an electric motor according to an embodiment; FIG. 3 is a perspective view of a stator according to an embodiment; FIG. 4 is a perspective view of an inner periphery of a stator according to an embodiment; FIG. 5 is a perspective view of a portion of a plurality of distal extension portions according to an embodiment where a fixed portion is fixed; FIG. 6 is a view of one slot of a stator according to an embodiment cut by a plane perpendicular to the axial direction; FIG. 7 is a view of a segment coil before assembly to a stator core according to an embodiment; FIG. 8 is a view of a segment coil according to an embodiment after twist forming; FIG. 9 is a wiring diagram of a stator coil according to an embodiment; FIG. 10 is a perspective view showing a modified example of a portion of a plurality of distal extension portions according to an embodiment where a fixed portion is fixed; FIG. 11 is another perspective view showing a modified example of a portion of a plurality of distal extension portions according to an embodiment where a fixed portion is fixed.

[0009] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. In this embodiment, an electric motor will be described as an example that is mounted on an electric swing shovel (an example of a work machine) and configured as a swing motor for swinging an upper swing body of the electric swing shovel.

[0010] In the following description, expressions indicating relative or absolute arrangements, such as "parallel," "orthogonal," "center," and "coaxial," do not only mean such arrangements or states in the strict sense, but also include arrangements or states in which there is a relative displacement with a tolerance or an angle or distance to the extent that the same function is obtained. In the drawings used in the following description, the scale of each component may be changed as appropriate to make each component recognizable.

[0011] <Construction machine> Figure 1 is a schematic diagram showing a construction machine according to an embodiment. The construction machine 100 according to this embodiment is an electric hydraulic excavator. The construction machine 100 may be a manned vehicle that is operated by a driver, or an unmanned vehicle that is operated without a driver.

[0012] The work machine 100 includes a running body 120 , an upper rotating body 140 , and a work implement 160 .

[0013] The running body 120 supports the work machine 100 so that it can travel. The running body 120 is equipped with running devices 121. The running devices 121 are, for example, a pair of left and right caterpillars. The running devices 121 are driven by a traveling motor 122. The upper rotating body 140 is supported on the running body 120 so that it can rotate about a rotation axis. The upper rotating body 140 rotates relative to the running body 120 by the rotation motor 114. The upper rotating body 140 has a compartment 141 that houses a drive system.

[0014] The work implement 160 is operably supported on the upper rotating body 140. The work implement 160 is hydraulically driven. The work implement 160 includes a boom 161, an arm 162, and an attachment 163. The attachment 163 is an example of a working tool. In the example shown in FIG. 1, the attachment 163 is a bucket. In the example shown in FIG. 1, the side of the upper rotating body 140 on which the work implement 160 is supported is the front, and the opposite side with respect to the front is the rear. In this embodiment, the left-right direction refers to the left and right relative to the front, and the up-down direction refers to the direction in which the rotation axis of the upper rotating body 140 extends.

[0015] The swing motor 114 is an electric motor that is driven by electricity and causes the upper swing body 140 to swing relative to the running body 120.

[0016] <Electric Motor> FIG. 2 is a cross-sectional view of the electric motor 1 according to the embodiment.

[0017] In this embodiment, the electric motor 1 is a swing motor 114. The electric motor 1 includes a rotor 2, a stator 3, and a housing 4 that accommodates the rotor 2 and the stator 3. The electric motor 1 is an inner rotor type motor in which the stator 3 is disposed outside the cylindrical rotor 2. The electric motor 1 is placed vertically so that the rotor shaft 20 of the rotor 2 is parallel to the swing axis.

[0018] In this embodiment, the upper side corresponds to one side parallel to the central axis CL of the rotor shaft 20, and the lower side corresponds to the other side parallel to the central axis CL of the rotor shaft 20. Hereinafter, the direction along the central axis CL of the rotor shaft 20 will be referred to as the "axial direction," the direction perpendicular to the axial direction will be referred to as the "radial direction," and the direction going around the central axis CL of the rotor shaft 20 will be referred to as the "circumferential direction."

[0019] The rotor 2 includes a rotor shaft 20, a rotor core 21, an upper plate 22, and a lower plate 23. The rotor shaft 20 is rotatably supported relative to the housing 4 by bearings 21A and 21B.

[0020] The rotor core 21 is formed by, for example, laminating electromagnetic steel sheets in the axial direction. The rotor core 21 is fitted onto the rotor shaft 20. The rotor core 21 rotates integrally with the rotor shaft 20. A plurality of permanent magnets (not shown) are embedded in the rotor core 21.

[0021] Each of the upper plate 22 and the lower plate 23 is annular plate members arranged coaxially with the rotor shaft 20. The upper plate 22 and the lower plate 23 are fitted to the rotor shaft 20. The upper plate 22 and the lower plate 23 sandwich the rotor core 21 from the outside in the axial direction. The upper plate 22 and the lower plate 23 rotate integrally with the rotor shaft 20 and the rotor core 21.

[0022] The stator 3 is fixed to the inner surface of the housing 4 so as to cover the outer periphery of the rotor 2. The stator 3 includes a cylindrical stator core 30 and a stator coil 31. Like the rotor core 21, the stator core 30 is formed by laminating electromagnetic steel sheets in the axial direction. A plurality of teeth are provided circumferentially on the inner periphery of the stator core 30. The stator coil 31 is wound around the teeth.

[0023] The housing 4 accommodates the rotor 2 and the stator 3. The housing 4 includes a cylindrical body 10, a ceiling portion 11 that closes the upper opening of the cylinder 10, and a bottom portion 13 that closes the lower opening of the cylinder 10. The cylinder 10, the ceiling portion 11, and the bottom portion 13 form a space 40 inside the housing 4 for accommodating the rotor 2 and the stator 3.

[0024] <Stator> Fig. 3 is a perspective view of the stator 3 according to the embodiment. Fig. 4 is a perspective view of the inner periphery of the stator 3 according to the embodiment. Fig. 5 is a perspective view of a portion of the plurality of distal end extensions according to the embodiment to which a fixing portion is fixed. Referring to Figs. 3 to 5 together, the stator 3 includes a cylindrical stator core 30 having a plurality of slots 30s arranged in a circumferential direction, a stator coil 31 inserted into each of the plurality of slots 30s and wound around the stator core 30, and having a plurality of distal end extensions 32e extending outward from a first axial end face 30f1 of the stator core 30 and arranged in a circumferential direction, and a fixing portion 38 that fixes circumferentially adjacent portions of the plurality of distal end extensions 32e to each other.

[0025] A plurality of slots 30s and a plurality of teeth 30t are arranged alternately around the inner periphery of the stator core 30. The plurality of slots 30s are arranged at equal intervals in the circumferential direction of the stator core 30. For example, an insulating material may be provided inside the slots 30s. Note that the configuration of the slots 30s (such as their arrangement, number, and shape) can be changed according to design specifications.

[0026] In this embodiment, the stator coil 31 is composed of multiple segment coils 39. For example, the segment coils 39 are rectangular wires with an insulating coating applied to the outer periphery of the wires. The segment coils 39 are not limited to the above, and may be composed of windings with circular or elliptical cross sections. The shape of the segment coils 39 can be changed according to the design specifications.

[0027] The stator coil 31 includes a first coil end 32 having a plurality of distal extensions 32e protruding from a first axial end face 30f1 of the stator core 30, and a second coil end 33 protruding from a second end face 30f2 of the stator core 30 opposite the first end face 30f1 in the axial direction. The axial direction of the stator core 30 corresponds to the direction along the central axis CL (see FIG. 2 ) of the rotor shaft 20. The first end face 30f1 of the stator core 30 corresponds to the upper end face of the stator core 30. The second end face 30f2 of the stator core 30 corresponds to the lower end face of the stator core 30. Note that the radial direction of the stator core 30 is a direction perpendicular to the axial direction, and the circumferential direction is a direction going around the central axis CL.

[0028] 2 , the electric motor 1 of this embodiment includes a rotor 2, a stator 3, and a housing 4 that accommodates the rotor 2 and the stator 3. The first coil end 32 is disposed axially on the opposite side (upper side) from the bottom 13 of the housing 4. Meanwhile, the second coil end 33 is disposed axially on the same side (lower side) as the bottom 13 of the housing 4. In this embodiment, the multiple distal extensions 32e are disposed axially on the opposite side (upper side) from the bottom 13 of the housing 4.

[0029] The stator 3 of this embodiment further includes power lines 35U, 35V, and 35W connected to the plurality of distal extension portions 32e. The plurality of distal extension portions 32e include connection extension portions 32j to which the power lines 35U, 35V, and 35W are connected and non-connection extension portions 32u to which the power lines 35U, 35V, and 35W are not connected. The power lines 35U, 35V, and 35W include stranded wires and terminals connected to the ends of the stranded wires. A power line connection portion 36 for connecting the power lines 35U, 35V, and 35W is connected to the connection extension portion 32j. The power line connection portion 36 is connected to the terminals of the power lines 35U, 35V, and 35W.

[0030] In this embodiment, the power line connection portion 36 and the terminals of the power lines 35U, 35V, and 35W are connected by fastening with bolts and nuts. The configurations of the power lines 35U, 35V, and 35W and the power line connection portion 36 are not limited to those described above and can be modified according to design specifications. For example, the power lines 35U, 35V, and 35W may include a bus bar, and the bus bar may be welded to the connection extension 32j. For example, the power lines 35U, 35V, and 35W may include a stranded wire and a terminal connected to an end of the stranded wire, and the terminal may be welded to the connection extension 32j. For example, the power lines 35U, 35V, and 35W may include a stranded wire and a first terminal connected to an end of the stranded wire, and a second terminal may be connected to the connection extension 32j, and the first and second terminals may be welded to each other.

[0031] In this embodiment, the stator coil 31 includes three-phase winding groups 34U1, 34U2, 34V1, 34V2, 34W1, and 34W2 connected in parallel to one another. The three-phase winding groups 34U1, 34U2, 34V1, 34V2, 34W1, and 34W2 are winding groups for the U, V, and W phases. The U, V, and W-phase winding groups 34U1, 34U2, 34V1, 34V2, 34W1, and 34W2 are arranged two by two in the circumferential direction of the stator core 30, such as U phase, U phase, V phase, V phase, W phase, and so on.

[0032] In this embodiment, the stator coil 31 includes a plurality of U-shaped segment coils 39 whose ends are connected to one another. The stator coil 31 is formed by winding a plurality of segment coils 39 whose ends are connected to one another in a wave-like pattern. Note that, although the example shown in the figure shows segment coils 39 with a square cross section, segment coils 39 with a round cross section may also be used. The cross-sectional shape of the segment coils 39 is not limited to the above and can be changed according to design specifications.

[0033] In the example shown in the figure, when a plurality of segment coils 39 inserted circumferentially around the stator core 30 are considered to be one winding portion 34A, 34B, 34C, and 34D, four winding portions 34A, 34B, 34C, and 34D are arranged radially around the stator core 30. The four winding portions 34A, 34B, 34C, and 34D include a first winding portion 34A, a second winding portion 34B, a third winding portion 34C, and a fourth winding portion 34D. The first winding portion 34A, the second winding portion 34B, the third winding portion 34C, and the fourth winding portion 34D are arranged in this order from the innermost to the outermost circumference of the stator core 30.

[0034] 6 is a cross-sectional view of one slot 30s of the stator 3 according to the embodiment, taken along a plane perpendicular to the axial direction. Referring to FIG. 6, the slot 30s is provided with multiple layers of segment coils 39. The slot 30s includes multiple layers L1 to L8 corresponding to the multiple layers.

[0035] In the illustrated example, the multiple layers L1 to L8 are arranged in this order from the radially inner side (bottom side in the figure), with the first layer L1 to the eighth layer L8. The first winding portion 34A is inserted into the first layer L1 and the second layer L2. The second winding portion 34B is inserted into the third layer L3 and the fourth layer L4. The third winding portion 34C is inserted into the fifth layer L5 and the sixth layer L6. The fourth winding portion 34D is inserted into the seventh layer L7 and the eighth layer L8. The number of layers is not limited to the above and can be changed according to design specifications.

[0036] Fig. 7 is a diagram showing the segment coil 39 before being assembled to the stator core 30 according to the embodiment. Fig. 8 is a diagram showing the segment coil 39 according to the embodiment after being twisted. Referring to Fig. 7 and Fig. 8 together, the segment coil 39 before being assembled to the stator core 30 is formed in a U-shape.

[0037] Specifically, the segment coil 39 includes a U-shaped portion 39a formed in a convex (U-shaped) shape that protrudes toward one side in the axial direction, and two straight portions 39b1, 39b2 that extend parallel to each other in a straight line from each end of the U-shaped portion 39a toward the other side in the axial direction. The U-shaped portion 39a constitutes the second coil end 33. The straight portions 39b1, 39b2 are inserted into the slots 30s, excluding the twisted portion. For example, in the first winding portion 34A of the segment coil 39, the end of one straight portion 39b1 is inserted into the first layer L1, and the end of the other straight portion 39b2 is inserted into the second layer L2.

[0038] For example, after the segment coil 39 is inserted into the slot 30s, the first extension portion 39c1 at one end is twisted toward one circumferential side, and the second extension portion 39c2 at the other end is twisted toward the other circumferential side. For example, of two segment coils 39 whose ends are connected to each other, the end of the twisted first extension portion 39c1 of one segment coil 39 is connected to the end of the twisted second extension portion 39c2 of the other segment coil 39 by welding or the like. In each segment coil 39, the connection portions between the end of the first extension portion 39c1 and the end of the second extension portion 39c2 are arranged so as to be aligned radially. Then, a neutral conductor 37N, such as a bus bar, is connected to a predetermined portion of the segment coil 39 by welding or the like. Note that each extension portion 39c1, 39c2 constitutes the first coil end 32.

[0039] 9 is a wiring diagram of the stator coil 31 according to this embodiment. Referring also to FIG. 9, the stator coil 31 employs a double star connection. In this embodiment, a first star connection including a U1-phase winding group 34U1, a V1-phase winding group 34V1, and a W1-phase winding group 34W1 is connected in parallel with a second star connection including a U2-phase winding group 34U2, a V2-phase winding group 34V2, and a W2-phase winding group 34W2.

[0040] The first star connection and the second star connection electrically connect the U phases (the U1-phase winding group 34U1 and the U2-phase winding group 34U2), the V phases (the V1-phase winding group 34V1 and the V2-phase winding group 34V2), and the W phases (the W1-phase winding group 34W1 and the W2-phase winding group 34W2).

[0041] The U1-phase winding group 34U1, V1-phase winding group 34V1, and W1-phase winding group 34W1 of the first star connection are electrically connected to the U2-phase winding group 34U2, V2-phase winding group 34V2, and W2-phase winding group 34W2 of the second star connection by being connected by a neutral conductor 37N. Note that the first star connection may be electrically connected by connecting the U1-phase winding group 34U1, V1-phase winding group 34V1, and W1-phase winding group 34W1 by a first neutral conductor 37N1 (not shown), and the second star connection may be electrically connected by connecting the U2-phase winding group 34U2, V2-phase winding group 34V2, and W2-phase winding group 34W2 by a second neutral conductor 37N2 (not shown).

[0042] <Fixing Portion> In this embodiment, the fixing portion 38 is an adhesive. Examples of the adhesive include an epoxy adhesive and an organic adhesive. The type of adhesive is not limited to the above and can be changed according to the design specifications.

[0043] In this embodiment, the adhesive has a high viscosity so that it does not flow downward even when applied between circumferentially adjacent portions of the distal extensions 32e. For example, a two-component epoxy resin adhesive may be used as the high-viscosity adhesive. The type of high-viscosity adhesive is not limited to the above and can be changed depending on the design specifications.

[0044] For example, a syringe (dispenser) or the like is used to inject (apply) a high-viscosity adhesive between circumferentially adjacent portions of the plurality of distal extensions 32e. High-viscosity adhesive has low fluidity and is easy to handle, allowing it to be precisely placed in the desired locations. Because the high-viscosity adhesive hardens after a curing time has elapsed, it can precisely fix the desired locations without gaps.

[0045] In this embodiment, the length AE (adhesion range) of the adhesive along the distal extension 32e is 10 mm or more. For example, by applying adhesive between circumferentially adjacent portions of the distal extension 32e within the application range DE (e.g., 20 mm or more) shown in the figure, it is possible to accurately fix a predetermined location over a wide area.

[0046] In this embodiment, the plurality of distal extensions 32e include a first connection extension 32j1 and a second connection extension 32j2 to which the power lines 35U, 35V, and 35W are connected and which are adjacent to each other in the circumferential direction, and a non-connection extension 32u to which the power lines 35U, 35V, and 35W are not connected. The fixing portion 38 fixes at least one of the first connection extension 32j1 and the second connection extension 32j2 to the non-connection extension 32u, excluding circumferentially adjacent portions of the first connection extension 32j1 and the second connection extension 32j2. In the illustrated example, the fixing portion 38 does not fix circumferentially adjacent portions of the first connection extension 32j1 and the second connection extension 32j2 to each other. The fixing portion 38 fixes adjacent portions of the first connecting extension portion 32j1 and the second connecting extension portion 32j2 to the non-connecting extension portion 32u in the circumferential direction.

[0047] In the present embodiment, the portions of the plurality of distal extensions 32e to which the fixing portions 38 are fixed are disposed radially inward of the stator core 30. In the example shown in the figure, the portions of the plurality of distal extensions 32e to which the fixing portions 38 are fixed are disposed radially innermost of the stator core 30. The fixing portions 38 are disposed adjacent to the radially innermost inner surfaces of the plurality of distal extensions 32e and on side surfaces that face each other.

[0048] In this embodiment, each of the plurality of distal extensions 32e includes an inclined portion 32s that intersects obliquely with respect to the axial direction and the circumferential direction. The fixing portion 38 fixes adjacent inclined portions 32s in the distal extensions 32e to each other in the circumferential direction. In the example shown in the figure, the adhesive area AE and the application area DE are provided along each inclined portion 32s.

[0049] <Effects> As described above, the stator 3 of this embodiment includes a cylindrical stator core 30 having a plurality of slots 30s arranged circumferentially, a stator coil 31 inserted into each of the plurality of slots 30s and wound around the stator core 30, and having a plurality of distal extensions 32e extending outward from a first axial end face 30f1 of the stator core 30 and arranged circumferentially, and a fixing portion 38 that fixes circumferentially adjacent portions of the plurality of distal extensions 32e to each other. For example, when fixing radially adjacent portions of the plurality of distal extensions 32e to each other, it is difficult to arrange the fixing portion 38 between the radially adjacent portions, resulting in problems of poor assembly and reduced fixing strength. In contrast, according to this embodiment, fixing circumferentially adjacent portions of the plurality of distal extensions 32e to each other makes it easy to arrange the fixing portion 38 between the circumferentially adjacent portions, thereby improving assembly. In addition, the fixing strength between circumferentially adjacent portions of the plurality of distal extensions 32e to each other can be improved. Therefore, the assembly efficiency and the fixing strength can be improved.

[0050] In the present embodiment, the fixing portion 38 is an adhesive. According to the present embodiment, by applying adhesive between the circumferentially adjacent portions of the plurality of distal extension portions 32 e, it is possible to fix the predetermined locations without any gaps.

[0051] In this embodiment, the adhesive has a high viscosity so that it does not flow downward even when provided between circumferentially adjacent portions of the plurality of distal extensions 32 e. According to this embodiment, by providing a high-viscosity adhesive between circumferentially adjacent portions of the plurality of distal extensions 32 e, it is possible to accurately fix the predetermined locations without gaps.

[0052] In this embodiment, the length AE of the portion of the adhesive that runs along the distal extension 32 e is 10 mm or more. According to this embodiment, by fixing adjacent portions of the plurality of distal extensions 32 e to each other by 10 mm or more in the circumferential direction, this contributes to further improving the fixing strength.

[0053] In this embodiment, the stator 3 further includes power lines 35U, 35V, and 35W connected to the distal extension portion 32e. This embodiment improves the fixing strength of the distal extension portion 32e to which the power lines 35U, 35V, and 35W are connected. This reduces the risk of damage to the terminals due to resonance of the power lines 35U, 35V, and 35W caused by vehicle body vibration.

[0054] In this embodiment, the plurality of distal extensions 32e include a first connection extension 32j1 and a second connection extension 32j2 to which the power lines 35U, 35V, and 35W are connected and which are adjacent to each other in the circumferential direction, and a non-connection extension 32u to which the power lines 35U, 35V, and 35W are not connected. The fixing portion 38 fixes at least one of the first connection extension 32j1 and the second connection extension 32j2 to the non-connection extension 32u, excluding the circumferentially adjacent portions of the first connection extension 32j1 and the second connection extension 32j2. According to this embodiment, by fixing only the minimum necessary locations, it is possible to further improve assembly ease and fixing strength.

[0055] In the present embodiment, the portions of the plurality of distal extensions 32e to which the fixing portions 38 are fixed are disposed radially inward of the stator core 30. According to the present embodiment, the fixing portions 38 can be easily disposed from the radially inner side of the stator core 30 relative to the portions of the plurality of distal extensions 32e to which the fixing portions 38 are fixed, which contributes to further improvement in ease of assembly.

[0056] In this embodiment, each of the plurality of distal extensions 32e includes an inclined portion 32s that intersects obliquely with respect to the axial direction and the circumferential direction. The fixing portion 38 fixes adjacent inclined portions 32s in the plurality of distal extensions 32e to each other in the circumferential direction. According to this embodiment, fixing adjacent inclined portions 32s in the plurality of distal extensions 32e to each other in the circumferential direction contributes to further improving the fixing strength.

[0057] In this embodiment, the stator coil 31 includes three-phase winding groups 34U, 34U2, 34V1, 34V2, 34W1, and 34W2 connected in parallel to one another. According to this embodiment, even when the stator coil 31 includes three-phase winding groups 34U, 34U2, 34V1, 34V2, 34W1, and 34W2 connected in parallel to one another, it is possible to improve assembly efficiency and fixing strength.

[0058] In this embodiment, the stator coil 31 includes a plurality of U-shaped segment coils 39 whose ends are connected to each other. According to this embodiment, even when a plurality of U-shaped segment coils 39 whose ends are connected to each other are included, it is possible to improve assembly ease and fixing strength.

[0059] The electric motor 1 of this embodiment includes a rotor 2, the stator 3, and a housing 4 that accommodates the rotor 2 and the stator 3. The multiple distal extensions 32e are arranged on the axial side opposite the bottom 13 of the housing 4. According to this embodiment, the multiple distal extensions 32e are accessible (the fixing portions 38 can be arranged) from the axial side opposite the bottom 13 of the housing 4 (the upper side), which contributes to further improving assembly ease.

[0060] <Modifications> In the above-described embodiment, the fixing portion is described as an adhesive, but this is not limiting. For example, as shown in Figures 10 and 11, the fixing portion may be a resin plate 138 to which an adhesive is applied. The resin plate 138 may be provided on the radially outer surfaces of circumferentially adjacent portions of the plurality of distal extension portions 32e. The resin plate may have a rectangular parallelepiped shape spanning the circumferentially adjacent portions when viewed from the radial direction. The resin plate may have a shape having a fixing surface (side surface) larger than the radially outer surfaces of the circumferentially adjacent portions.

[0061] For example, the member to which the adhesive is applied is not limited to the above, and may be a plate other than a resin plate, or a film-like or sheet-like member. Although not shown, the fixing portion may be a string member (such as a thread or a cable tie) capable of fastening circumferentially adjacent portions of the plurality of distal extension portions together. The fixing portion may be an impregnated member (such as a sponge, cloth, or fiber) impregnated with adhesive. The fixing portion may be a molded member capable of fastening circumferentially adjacent portions of the plurality of distal extension portions together. The fixing portion may be a resin member capable of fastening circumferentially adjacent portions of the plurality of distal extension portions together. In this case, the fixing portion may be, for example, a molded resin member. When fixing using a resin member, the coils may be fixed together by inserting, for example, an E-shaped molded resin member from the side of the coils. The form of the fixing portion can be changed according to design specifications.

[0062] In the above-described embodiment, the adhesive is described as having a high viscosity that prevents the adhesive from flowing downward even when provided between circumferentially adjacent portions of the distal extension portions, but this is not limited thereto. For example, the adhesive may have a viscosity (low viscosity) that causes the adhesive to flow downward when provided between circumferentially adjacent portions of the distal extension portions. The viscosity of the adhesive can be changed according to the design specifications.

[0063] In the above-described embodiment, the length of the adhesive along the distal extension portion is 10 mm or more, but this is not limited thereto. For example, the length of the adhesive along the distal extension portion may be less than 10 mm. The length of the adhesive along the distal extension portion can be changed according to the design specifications.

[0064] In the above-described embodiment, the stator further includes a power line connected to the distal extension portion. However, this is not limiting. For example, the power line does not have to be connected to the distal extension portion. For example, a neutral line may be connected to the distal extension portion. For example, other components (such as a bus bar) may be connected to the distal extension portion. The installation mode of the power line can be changed according to design specifications.

[0065] In the above-described embodiment, the plurality of distal extensions include a first connection extension and a second connection extension, which are connected to the power lines and are adjacent to each other in the circumferential direction, and a non-connection extension, to which the power lines are not connected. The fixing portion fixes at least one of the first connection extension and the second connection extension, excluding the circumferentially adjacent portions of the first connection extension and the second connection extension, to the non-connection extension. However, this is not limited to this. For example, the fixing portion may fix the circumferentially adjacent portions of the first connection extension and the second connection extension. The fixing manner of the fixing portion can be changed depending on the design specifications.

[0066] In the above-described embodiment, the portions of the distal extensions to which the fixing portions are fixed are disposed radially inward of the stator core, but this is not limiting. For example, the portions of the distal extensions to which the fixing portions are fixed may be disposed radially outward of the stator core. The arrangement of the portions of the distal extensions to which the fixing portions are fixed can be changed according to design specifications.

[0067] In the above-described embodiment, each of the plurality of distal extension portions includes an inclined portion that intersects obliquely with respect to the axial direction and the circumferential direction, and the fixing portion fixes adjacent inclined portions of the plurality of distal extension portions to each other in the circumferential direction. However, this is not limited to this. For example, each of the plurality of distal extension portions may include a straight portion that extends along the axial direction, and the fixing portion may fix adjacent straight portions of the plurality of distal extension portions to each other in the circumferential direction. The manner in which adjacent portions of the plurality of distal extension portions are fixed to each other in the circumferential direction can be changed depending on the design specifications.

[0068] In the above-described embodiment, the stator coil has been described as having three-phase winding groups connected in parallel, but this is not limiting. For example, the stator coil may have three-phase winding groups connected in series. The winding groups and the configuration of the stator (e.g., the relationship between poles, phases, and slots) can be changed according to design specifications.

[0069] In the above-described embodiment, the stator coil is described as including a plurality of U-shaped segment coils whose ends are connected to each other, but this is not limiting. For example, the stator coil may include a coil wound in a continuous wave pattern. The configuration of the stator coil can be changed according to the design specifications.

[0070] In the above-described embodiment, the electric motor includes a rotor, the stator, and a housing that accommodates the rotor and the stator, and the plurality of distal extensions are disposed on the axial side opposite the bottom of the housing. However, this is not limiting. For example, the plurality of distal extensions may be disposed on the same axial side as the bottom of the housing (opposite the opening). The arrangement of the plurality of distal extensions can be changed according to design specifications.

[0071] In the above-described embodiment, the electric motor is mounted on an electric swing shovel, and an electric swing motor for swinging the upper swing body of the electric swing shovel has been described as an example, but this is not limiting. For example, the electric motor may be mounted on other work machines such as a wheel loader, a bulldozer, or a dump truck. For example, the electric motor may be configured as a drive motor for driving a work implement or a drive motor for driving a traveling device. The type of work machine on which the electric motor is mounted and the object driven by the electric motor can be changed depending on the design specifications.

[0072] In the above-described embodiment, the electric motor is vertically disposed so that the rotor shaft is parallel to the rotation axis, but this is not limiting. For example, the electric motor may be horizontally disposed so that the rotor shaft is perpendicular to the rotation axis. For example, the electric motor may be disposed at an angle so that the rotor shaft intersects the rotation axis at an angle. The arrangement of the electric motor can be changed according to the design specifications.

[0073] In the above-described embodiment, the electric motor is an inner rotor type electric motor in which a stator is disposed outside a cylindrical rotor, but this is not limiting. For example, the electric motor may be an outer rotor type electric motor in which a stator is disposed inside a cup-shaped rotor. The type of electric motor can be changed depending on the design specifications.

[0074] Although one embodiment has been described above with reference to the drawings, the specific configuration is not limited to that described above, and additions, omissions, substitutions, and other modifications to the configuration are possible within the scope of the present disclosure, and the above-described embodiments can also be combined as appropriate.

[0075] 1...electric motor, 2...rotor, 3...stator, 4...housing, 13...bottom, 30...stator core, 30f1...first end face, 30s...slot, 31...stator coil, 32e...terminal extension portion, 32j1...first connection extension portion, 32j2...second connection extension portion, 32u...non-connection extension portion, 32s...inclined portion, 34U1, 34U2, 34V1, 34V2, 34W1, 34W2...winding group, 35...power line, 38...fixed portion, 39...segment coil, 100...work machine, 114...swing motor, 120...traveling body, 140...upper swing body, 160...work machine, AE...adhesion range (length of portion where adhesive runs along terminal extension portion)

Claims

1. A stator comprising: a cylindrical stator core having a plurality of slots aligned in the circumferential direction; a stator coil inserted into each of the plurality of slots and wound around the stator core, the stator coil having a plurality of end side extensions extending outward from a first axial end face of the stator core and aligned in the circumferential direction; and a fixing portion that fixes adjacent portions of the end side extensions to each other in the circumferential direction.

2. The stator according to claim 1, wherein the fixing portion is an adhesive.

3. A stator as set forth in claim 2, wherein the adhesive has such a high viscosity that it does not flow downward even when applied between circumferentially adjacent portions of the plurality of end side extensions.

4. A stator as claimed in claim 2 or 3, wherein the length of the portion of said adhesive along said distal extension is 10 mm or more.

5. A stator as claimed in any one of claims 1 to 3, further comprising a power line connected to the end side extension portion.

6. A stator as described in claim 5, wherein the multiple end side extension portions include a first connection extension portion and a second connection extension portion to which the power lines are connected and which are adjacent to each other in the circumferential direction, and a non-connection extension portion to which the power lines are not connected, and the fixing portion fixes between at least one of the first connection extension portion and the second connection extension portion and the non-connection extension portion, excluding portions of the first connection extension portion and the second connection extension portion that are adjacent to each other in the circumferential direction.

7. A stator according to any one of claims 1 to 3, wherein the portions of the plurality of end side extensions to which the fixing portion is fixed are disposed radially inward of the stator core.

8. A stator as described in any one of claims 1 to 3, wherein each of the multiple end side extension portions includes an inclined portion that intersects obliquely with the axial direction and the circumferential direction, and the fixing portion fixes the inclined portions adjacent to each other in the circumferential direction in the multiple end side extension portions.

9. A stator according to any one of claims 1 to 3, wherein the stator coil comprises three-phase winding groups connected in parallel with each other.

10. A stator as claimed in any one of claims 1 to 3, wherein the stator coil comprises a plurality of U-shaped segment coils whose ends are connected to each other.

11. An electric motor comprising: a rotor; a stator according to any one of claims 1 to 3; and a housing that accommodates the rotor and the stator.

12. The electric motor according to claim 11, wherein the plurality of end extensions are disposed on a side opposite the bottom of the housing in the axial direction.

13. A working machine comprising: a running body; an upper rotating body supported on the running body so as to be rotatable about a rotation axis; a working machine supported operably on the upper rotating body; and an electric motor according to claim 11 configured as a rotating motor for rotating the upper rotating body relative to the running body.

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