JP2023137416A - Stator manufacturing method for rotary electric machine - Google Patents

Abstract

To reduce a cavity in a liquid resin material of an impregnation object part which can be generated when a workpiece is immersed in a tank of a liquid resin material, while securing the thickness of an insulation coating.SOLUTION: A stator manufacturing method for a rotary electric machine includes: a mounting step of forming a workpiece of a stator core and a stator coil; a joint step of joining coil pieces, after the mounting step; a first impregnation step of impregnating a circular impregnation object part including a joint part of the workpiece with a liquid resin material, after the joint step; a second impregnation step of impregnating the tank of the liquid resin material with the workpiece so that at least a part of the impregnation object part in the first impregnation step is immersed, after the first impregnation step; and a curing step of curing the liquid resin material impregnating the impregnation object part, after the second impregnation step, wherein the second impregnation step includes moving the workpiece, and thereby forming a workpiece inclination attitude in which a part of the whole circumference of the impregnation object part is separated from the liquid surface of the liquid resin material of the tank twice or more, in such a manner that a part of a circumferential position changes.SELECTED DRAWING: Figure 25

Description

The present disclosure relates to a method for manufacturing a stator for a rotating electric machine.

A workpiece for a rotating electrical machine in which a plurality of coil pieces forming a stator coil are attached to a stator core is prepared, and the tips of the plurality of coil pieces are joined to each other at one end in the axial direction of the workpiece, and the joined part (exposed conductor part) A method of manufacturing a stator for a rotating electric machine is known in which a region to be impregnated including a part of the rotor is impregnated with a liquid resin material, and then the liquid resin material is cured to cover the joint portion with an insulating coating of the resin material. In this type of manufacturing method, the workpiece is immersed in a tank of liquid resin material (the area to be impregnated is impregnated with the liquid resin material) with the workpiece in a position with the joint part facing downward, and then In order to suppress voids in the insulating coating (resin mold) that may occur due to this, a technique has been proposed in which a liquid resin material is heated and cured in a positive pressure environment.

Japanese Patent Application Publication No. 2021-136787

However, with the above-mentioned conventional techniques, it is difficult to reduce cavities that may occur when the workpiece is immersed in a tank of liquid resin material (cavities caused by air trapped below the workpiece). In particular, in order to ensure the thickness of the insulation coating, when the step of impregnating with liquid resin material is performed in two or more times, when the workpiece is immersed in the tank of liquid resin material from the second time onward, the impregnating process before the previous one is Due to the uneven shape of the liquid resin material, air tends to accumulate below the workpiece. Such cavities can cause voids in the insulation coating (resin mold) after curing.

Therefore, in one aspect, the present disclosure aims to reduce cavities in the liquid resin material at the part to be impregnated, which may occur when a workpiece is immersed in a tank of the liquid resin material, while ensuring the thickness of the insulating coating. shall be.

In one aspect, a mounting step of mounting a plurality of coil pieces forming a stator coil on a stator core to form a workpiece;
After the mounting step, a joining step of joining the respective tip portions of one of the coil pieces and the other of the coil pieces at one end in the axial direction of the work;
After the joining step, a first impregnation step of impregnating an annular impregnation target region of the work including the joint between the tips of the workpiece with a liquid resin material;
After the first impregnation step, a second impregnation step of immersing the workpiece in a tank of liquid resin material so that at least a part of the region to be impregnated in the first impregnation step is immersed;
After the second impregnation step, a curing step of curing the liquid resin material impregnated into the region to be impregnated,
In the second impregnation step, by moving the workpiece, a tilted posture of the workpiece is changed so that a part of the entire circumference of the region to be impregnated is away from the surface of the liquid resin material in the tank. A method for manufacturing a stator for a rotating electric machine is provided, which includes forming the stator twice or more in a manner in which the directional position changes.

In one aspect, according to the present disclosure, it is possible to reduce cavities in the liquid resin material in the region to be impregnated, which may occur when the workpiece is immersed in a tank of the liquid resin material, while ensuring the thickness of the insulation coating. becomes.

It is a schematic flowchart which shows an example of the stator manufacturing method for rotating electric machines. FIG. 2 is a diagram schematically showing the entire workpiece for forming a stator for a rotating electric machine. FIG. 2 is a cross-sectional view along the axial direction of a workpiece in a state where a coil piece is assembled to a stator core. It is a front view of one coil piece. FIG. 3 is a schematic cross-sectional view of a coil piece. FIG. 3 is an explanatory diagram of a joint portion, and corresponds to an enlarged view of section Q1 in FIG. 2. FIG. 3 is a diagram schematically showing a workpiece in a side view before being immersed in a tank of liquid resin material. FIG. 2 is a diagram schematically showing a workpiece immersed in a tank of liquid resin material in a side view. It is a figure which shows typically the state of a workpiece|work in a pulling-up process from a side view. FIG. 3 is a diagram schematically showing, in a side view, the state of a workpiece undergoing an outer diameter side resin curing process in an outer diameter side resin curing process. FIG. 3 is a diagram schematically showing a side view of a workpiece that has been placed in an upward posture in an up-and-down reversal step after an outer diameter side resin curing process. FIG. 3 is an explanatory diagram of a preferable rotation axis when turning a workpiece upside down. FIG. 6 is an explanatory diagram of a rotating shaft according to a comparative example. FIG. 3 is a diagram schematically showing, in a side view, the state of a workpiece undergoing a top resin curing process in a top resin curing process. FIG. 2 is a diagram schematically showing, in a side view, the state of a workpiece undergoing an inner diameter side resin curing process in an inner diameter side resin curing process. FIG. 6 is a diagram schematically showing, in a side view, the state of a workpiece in a downward posture immediately before undergoing a second dipping process. FIG. 6 is a diagram schematically showing a workpiece in an upward posture after the second insulation coating step is completed. FIG. 2 is a diagram schematically showing the state of the workpiece in a side view in a heating process. It is an explanatory view of the effect in a heating process. FIG. 3 is a diagram schematically showing an example of a cooling structure. It is an explanatory view of a preferred method concerning a dipping process (Step S208). FIG. 21 is an explanatory diagram of the effect of the method shown in FIG. 20; FIG. 6 is an explanatory diagram of inconveniences that may occur in a dipping process according to a comparative example. It is an explanatory view of other inclined postures. It is an explanatory view of other inclined postures. It is an explanatory view of a preferred method concerning a dipping process (Step S208) in a second insulation coating process. FIG. 6 is an explanatory diagram of inconveniences that may occur in a dipping process according to a comparative example. FIG. 7 is an explanatory diagram of preferred examples of eight types of tilted postures.

Hereinafter, each embodiment will be described in detail with reference to the accompanying drawings. Note that the dimensional ratios in the drawings are merely examples, and are not limited thereto, and shapes, etc. in the drawings may be partially exaggerated for convenience of explanation.

The method for manufacturing a stator for a rotating electric machine described below can be applied to any stator for a rotating electric machine as long as the coil end portion has a joining portion of coil pieces. Below, as a preferred application example, a method for manufacturing a stator for a rotating electric machine that can function as a power source that generates propulsive force for a vehicle will be described.

FIG. 1 is a schematic flowchart showing an example of a method for manufacturing a stator for a rotating electrical machine. Note that FIG. 1 is a flowchart showing a schematic flow, and further additional steps may be included at any stage. 2 to 6 are explanatory diagrams of the workpiece W. FIG. 2 is a diagram schematically showing the entire workpiece W including a stator core 112 and a stator coil 114 for forming the stator 10 for a rotating electric machine. FIG. 3 is a cross-sectional view along the axial direction of the workpiece W in which the coil piece 52 is assembled to the stator core 112. FIG. 4 is a front view of one of the plurality of coil pieces 52. FIG. 5 is a schematic cross-sectional view of the coil piece 52. FIG. 6 is an explanatory diagram of the joint portion 400, and corresponds to an enlarged view of portion Q1 in FIG. 7 to 18 are explanatory diagrams of the present manufacturing method, and FIGS. 7 to 11 and FIGS. 13 to 18 are diagrams schematically showing the state of the workpiece W in each step, etc. in side view. FIG. 12 is an explanatory diagram of a preferable rotation axis I1 when turning the workpiece W upside down. FIG. 12 schematically shows a part of the work gripping section 1000 of the manufacturing apparatus. FIG. 12A is an explanatory diagram of the rotation axis I2 according to a comparative example.

The Z direction is shown in FIG. 2 and the like. The Z direction corresponds to the up-down direction, and the Z1 side and the Z2 side correspond to the upper side and the lower side, respectively. Moreover, the Y direction is shown in FIG. 3 and the like. The Y direction corresponds to the radial direction, with the Y1 side corresponding to the radially outer side and the Y2 side representing the radially inner side (the side closer to the central axis I of the stator core 112).

In the following description, unless otherwise specified, the axial direction refers to the direction in which the central axis I of the stator core 112 (=the central axis of the workpiece W) extends, and the radial direction refers to the diameter around the central axis I. Point in a direction. Therefore, the radially outer side refers to the side away from the central axis I, and the radially inner side refers to the side closer to the central axis I. Further, the axially outer side refers to the side away from the axial center of the stator core 112, and the axially inner side refers to the side closer to the axial center of the stator core 112. Further, the circumferential direction corresponds to the direction of rotation around the central axis I.

This manufacturing method first includes a mounting step (step S200) in which a plurality of coil pieces 52 forming the stator coil 114 are mounted on the stator core 112 to form an assembly (hereinafter also referred to as "work W").

Here, the stator coil 114 includes a U-phase coil, a V-phase coil, and a W-phase coil (hereinafter referred to as "phase coil" when U, V, and W are not distinguished). The base end of each phase coil is connected to an input terminal (not shown), and the end of each phase coil is connected to the end of another phase coil to form a neutral point. That is, stator coil 114 is star-connected. However, the connection mode of the stator coil 114 may be changed as appropriate depending on the required motor characteristics, etc. For example, the stator coil 114 may be delta connected instead of star connected.

Each phase coil of the stator coil 114 is constructed by combining a plurality of coil pieces 52. The coil piece 52 is in the form of a segment coil (segment conductor) obtained by dividing a phase coil into units that are easy to assemble (for example, units inserted into two slots 23). As shown in FIG. 5, the coil piece 52 is formed by covering a linear conductor (flat wire) 120 with a substantially rectangular cross section with an insulating film 130. Here, the linear conductor is made of copper, for example. However, in variations, the linear conductor may be formed from other conductive materials, such as iron. Further, the cross-sectional shape of the linear conductor may be other than rectangular.

In the example shown in FIG. 4, one coil piece 52 is formed into a substantially U-shape having a pair of linear slot accommodating parts 50 and a transition part 54 connecting the pair of slot accommodating parts 50. It's fine. The transition portion 54 on the other side in the axial direction (upper side in FIG. 4) may be formed by forming in the circumferential direction from the state shown in FIG. At the end of the transition portion 54 on the other side in the axial direction (upper side in FIG. 4), a coupling portion 40 that is coupled to a coupling portion 40 of the transition portion 54 of another coil piece 52 is set. Note that the coupling portion 40 is a portion where the insulating film 130 is removed (that is, a portion where a conductor portion related to a linear conductor is exposed).

When assembling the coil piece 52 to the stator core 112, the pair of slot accommodating portions 50 are each inserted into the slot 23 between the teeth 22 (see FIG. 3). In this case, the coil pieces 52 can be assembled, for example, in the axial direction.

A plurality of slot accommodating portions 50 of the coil pieces 52 shown in FIG. 4 are inserted into one slot 23 in a line in the radial direction. Therefore, at both ends of the stator core 112 in the axial direction, a plurality of transition portions 54 extending in the circumferential direction are arranged in the radial direction. Note that the transition portion 54 (and the coupling portion 40 that is a part thereof) forms a coil end portion 114A that is a portion that projects axially outward from the axial end surface of the stator core 112.

Note that the coil piece 52 may be wound around the stator core 112 in, for example, an overlapping form. In the example shown in FIG. 4, the lower transition portion 54 may have an offset portion 521B that is offset in the direction of being separated from each other by one layer in the radial direction. The upper transition portion 54 may also have a similar offset portion 521A.

Note that although the stator core 112 and the stator coil 114 have specific structures in FIGS. 2 to 5, the structures of the stator core 112 and the stator coil 114 are arbitrary as long as the stator coil 114 has the coupling portion 40. Further, the manner in which the stator coil 114 is wound is arbitrary, and may be wound in a manner other than the above-mentioned overlapped winding, such as wave winding.

Next, the present manufacturing method includes a joining step (step S202) of joining the joining portions 40, which are the tip ends of one coil piece 52 and the other coil piece 52, at one end in the axial direction of the workpiece W. include. The coupling parts 40 may be overlapped and joined at opposing sides. The joining portions 40 may be joined together using any method, but welding may be used, for example. In this case, welding may be achieved by any method such as laser welding or TIG welding. FIG. 6 schematically shows a joint portion 400 including a welding portion 401 (joint portion) formed in two joint portions 40 stacked in the radial direction.

For example, when a plurality of coil pieces 52 are installed in each slot 23 of the stator core 112 in a manner in which four or more coil pieces overlap in the radial direction, the joining process is performed between two radially adjacent connecting parts 40 (tip parts). A plurality of sets may be joined in the radial direction, with each set being considered as one set.

Note that the bonding range of the bonding portions 40, the posture of the bonding portions 40 when bonding (the posture when overlapping), etc. are arbitrary. For example, in FIG. 6, the joint parts 40 are vertically upright and overlapped in the radial direction, but they may be overlapped in an X-shaped cross-shape when viewed in the radial direction, or they may be overlapped diagonally. Only the coupling portions 40 may be superimposed on each other in the radial direction in the orientation of the direction. Moreover, the coupling parts 40 may be stacked in the axial direction in a posture extending in the radial direction.

In the bonding step, not only the coil pieces 52 may be bonded to each other, but also the coil pieces 52 may be bonded to a bus bar or a terminal block (an output bus bar for connection to an inverter (not shown)). FIG. 2 schematically shows a neutral point bus bar 59 as an example of such a bus bar. The neutral point bus bar 59 is a bus bar that forms the above-mentioned neutral point.

In this embodiment, as an example, the joint portion 400 is provided only on one side of the stator core 112 in the axial direction. Hereinafter, for distinction, the side having the joint portion 400 of both axial sides of the stator core 112 (or both axial sides of the workpiece W) will also be referred to as the lead side. In addition, in a modification, the joint portions 400 may be set on both sides of the stator core 112 in the axial direction.

Next, in this manufacturing method, the workpiece W is set at the starting position (workpiece loading position) for the insulation coating process (step S204). At this time, the workpiece W may be set with the lead side facing upward (that is, the joint portion 400 facing upward). Hereinafter, this posture in which the lead side is on the upper side will also be referred to as the "upward posture of the workpiece W."

Next, the present manufacturing method includes, as the first step of the insulation coating step, an up-down reversal step (step S206) in which the posture of the workpiece W is reversed up and down. That is, the workpiece W is turned upside down so that the lead side is on the lower side (that is, the joint part 400 is on the lower side). Hereinafter, such a posture with the lead side facing downward will also be referred to as a "downward posture of the workpiece W." The vertical reversal of the posture of the workpiece W may be realized by a manufacturing device (for example, an articulated robot having a hand that grips the workpiece W), not shown.

Next, the present manufacturing method includes a dipping step (step S208) of dipping the workpiece W into the tank 600 of the liquid resin material M0. FIG. 7 is a side view schematically showing the work W before being immersed in the tank 600 of the liquid resin material M0, and FIG. 8 is a diagram schematically showing the work W immersed in the tank 600 of the liquid resin material M0. FIG. 2 is a diagram schematically showing a side view. In this example, the liquid resin material M0 is preferably a resin material that has the property of being hardened by heating and the property of being hardened by a polymerization reaction when irradiated with ultraviolet rays. Note that the tank 600 may have an annular shape corresponding to the annular impregnation target region when viewed from above.

In the dipping step, the workpiece W maintains a downward attitude so that the part to be impregnated at the axial end (the lower end in the downward attitude) of the workpiece W is immersed in the liquid resin material M0 (i.e., the liquid resin material (below the liquid level of M0). The parts of the workpiece W to be impregnated are set to the parts of the plurality of coil pieces 52 of the workpiece W. Specifically, the part of the workpiece W to be impregnated is the axial end (lead side end) of the plurality of coil pieces 52 and includes the joint part 400. More specifically, the part of the workpiece W to be impregnated is the part of each coil piece 52 of the workpiece W where the conductor (conductor part related to the linear conductor) is exposed (the part including the joint part 400). include. The region to be impregnated has an annular shape around the central axis I when viewed in the axial direction, and includes a portion of the coil end portion 114A (a portion on the axial end side).

In addition, in this example, the dipping process is performed twice for one workpiece W, as described later. In this case, the parts of the workpiece W to be impregnated in each dipping step may be completely the same, or may be partially different, as will be described later.

In the immersion process, the workpiece W may be maintained in a downwardly immersed state for a certain period of time by a manufacturing device (for example, an articulated robot having a hand that grips the workpiece W) (not shown).

Next, the present manufacturing method includes a lifting step (step S210) in which the workpiece W is pulled up from the tank 600. The lifting of the workpiece W may be realized by a manufacturing device (not shown) (for example, an articulated robot having a hand for grasping the workpiece W). FIG. 9 schematically shows the workpiece W in a downward posture after being pulled up. After being pulled up, the workpiece W in the downward position has a liquid resin material M0 (schematically illustrated by the hatched area M1 in FIG. 9) in the impregnation target area at the axial end (lower end in the downward position). Impregnated.

Next, the present manufacturing method includes an outer diameter side resin curing process (an example of an irradiation process) in which a resin curing process of liquid resin material M0 is performed on the side surface of the part to be impregnated with respect to the workpiece W pulled up from the tank 600 and facing downward. ) (step S212). Hereinafter, in order to distinguish it from the resin curing process performed in the upper surface resin curing process (step S216), which will be described later, the resin curing process performed in the outer diameter side resin curing process (step S212) will be referred to as "outer diameter side resin curing process". Also referred to as "processing".

In this embodiment, the outer diameter side resin curing process includes irradiating the side surface of the part of the workpiece W to be impregnated with ultraviolet rays. FIG. 9 schematically shows a state in which the outer diameter side resin curing process is being performed. In addition, in FIG. 9 (as well as FIG. 10, which will be described later), the liquid resin material M0 impregnated into the workpiece W is schematically shown by a hatched area M1. In the example shown in FIG. 10, the ultraviolet irradiation device 900 irradiates the radially outer side surface of the part to be impregnated of the workpiece W with ultraviolet rays (see arrow R10). As a result, the radially outer portion (mainly the surface portion) of the liquid resin material M0 impregnated into the part of the workpiece W to be impregnated is hardened.

The ultraviolet irradiation device 900 preferably irradiates the radially outer side surface of the part of the workpiece W to be impregnated with ultraviolet rays over the entire circumference. Thereby, the liquid resin material M0 in the radially outer portion can be cured over the entire circumference of the region to be impregnated. In this case, the workpiece W may be rotated around the central axis I, or the ultraviolet irradiation device 900 may be rotated. Alternatively, a plurality of ultraviolet irradiation devices 900 may be disposed circumferentially outside the workpiece W in the radial direction.

The ultraviolet irradiation device 900 is preferably positioned with respect to the workpiece W such that the optical axis 901 is substantially perpendicular to the radially outer side surface of the part of the workpiece W to be impregnated. That is, the ultraviolet irradiation device 900 is preferably positioned with respect to the workpiece W so that the optical axis 901 is located within a substantially horizontal plane. Here, "approximately" is a concept that includes an error of 10% or less, for example. Further, the ultraviolet irradiation device 900 is preferably positioned with respect to the workpiece W such that the optical axis 901 passes through the region of the workpiece W to be impregnated, and more preferably, the optical axis 901 is the axis of the region of the workpiece W to be impregnated. It is positioned relative to the workpiece W so as to pass near the direction center. In this case, the liquid resin material M0 in the radially outer portion of the part of the workpiece W to be impregnated can be efficiently hardened.

In this manner, according to the present embodiment, while the work W maintains the downward posture after being pulled up from the tank 600, the radially outer portion of the liquid resin material M0 impregnated into the region to be impregnated is hardened. Therefore, it is possible to reduce inconveniences that may occur when the workpiece W pulled up from the tank 600 is turned upside down without performing such outer diameter side resin curing treatment. That is, when the work W pulled up from the tank 600 is turned upside down in the next up-down reversal step (step S214) without performing the outside diameter side resin curing process, the liquid resin impregnated into the part of the work W to be impregnated. The material M0 tends to sag downward due to its own weight (see arrow R11 in FIG. 11). In this case, there is a possibility that the exposed range (the range not covered with the resin member) on the side surface of the coil end portion 114A becomes unnecessarily narrow. If the exposed range on the side surface of the coil end portion 114A is insufficient, there is a risk that the cooling efficiency when a refrigerant (for example, oil) is supplied to the side surface of the coil end portion 114A during operation of the rotating electrical machine may decrease (see FIG. 19). (described later). Furthermore, if the liquid resin material M0 on the radially outer side surface of the region to be impregnated drips downward, it may adhere to the axial end surface (upper end surface) of the stator core 112. In this case, it is necessary to separately remove the liquid resin material M0 attached to the stator core 112 using a scraper or the like. On the other hand, according to this embodiment, as described above, such inconvenience can be reduced.

Next, the manufacturing method includes an up-down reversal step (step S214) in which the posture of the workpiece W is reversed up and down. That is, the workpiece W is turned upside down from a downward posture to an upward posture. FIG. 11 schematically shows a workpiece W that has been vertically inverted to an upward position.

By the way, if the workpiece W is turned upside down in a state where the workpiece W is impregnated with the liquid resin material M0, there is a problem that the liquid resin material M0 is likely to scatter due to centrifugal force. If the liquid resin material M0 is scattered, the material may be wasted, and there is also a risk that the thickness and coverage of the insulating coating covering the joint portion 400 of the coil end portion 114A may be insufficient. Furthermore, if the rotational speed of the workpiece W is reduced in order to reduce centrifugal force, the time required for the up-and-down reversal process increases, and CT (Cycle Time) tends to increase.

Therefore, in this embodiment, the workpiece W is preferably rotated from a downward posture by being rotated around a rotation axis I1 in a horizontal plane passing through the region to be impregnated, as schematically shown by an arrow R12 in FIG. The body is flipped upside down into an upward facing position. That is, the workpiece gripping section 1000 turns the workpiece W upside down so that the workpiece W rotates around the rotation axis I1 in a horizontal plane passing through the region to be impregnated. As a result, the distance from the rotation axis I1 to the region to be impregnated (the radius that affects the centrifugal force) can be efficiently reduced, and even if the rotation is reversed at a relatively high rotation speed, the centrifugal force will not become excessive ( For example, centrifugal force that would cause the liquid resin material M0 to scatter is not generated). In this way, it is possible to prevent the liquid resin material M0 from scattering from the work W and also to prevent an increase in CT.

Here, while the work W is being turned upside down, the rotation axis I1 may be fixed or may be translated. For example, the rotation axis I1 may be moved upward while rotating the workpiece W. Thereby, while moving the workpiece W to the next process, the posture of the workpiece W can be turned upside down in a manner that prevents the liquid resin material M0 from scattering. Note that such an operation is suitable when the work gripping section 1000 is attached to a hand of an articulated robot.

Note that the rotation axis I1 may be fixed in a constant positional relationship with respect to the workpiece W to be reversed during the reversal operation, or the positional relationship with respect to the workpiece W may change only during a part of the reversal operation. It's okay. For example, when the workpiece gripping section 1000 is attached to the hand of an articulated robot, the positional relationship between the rotational axis I1 and the workpiece W is changed only for a part of the period, such as the final stage of the reversal operation, so that the rotational axis I1 is the object of impregnation. It may deviate from the positional relationship passing through the parts.

Further, the rotation axis I1 preferably passes through the region to be impregnated as described above so that the radius related to the centrifugal force becomes small, but the invention is not limited thereto. When the rotation radius of the axial center of the stator core 112 around the rotation axis I1 is taken as the reference radius, a significant effect can be obtained if the rotation radius of the region to be impregnated around the rotation axis I1 is equal to or less than the reference radius. For example, the rotation axis I1 may be set to pass between the axial center of the stator core 112 and the region to be impregnated. Even in this case, the radius related to centrifugal force (rotation of the impregnation target area around the rotation axis Since the radius) becomes smaller, the above-mentioned effects can still be obtained. In the comparative example shown in FIG. 12A, the workpiece W held by the loader hand 1200 is rotated around a rotation axis I2 located outside the workpiece W on the opposite side from the region to be impregnated. In this case, the radius r2 related to the centrifugal force (the radius of rotation of the region to be impregnated around the rotation axis I2) becomes relatively large (at least the axial length of the stator core 112), and the above-mentioned problems such as scattering of the liquid resin material M0 occur. Issues are likely to arise.

Next, the present manufacturing method includes a top resin curing process (an example of an irradiation process) in which a liquid resin material M0 is cured on the top surface of the part to be impregnated with respect to the workpiece W that has been inverted to an upward position (step S216 )including. Hereinafter, the resin curing process related to the top resin curing step will also be referred to as "top resin curing process" to distinguish it from the above-mentioned outer diameter side resin curing process.

In this embodiment, the upper surface resin curing process includes irradiating the upper surface of the part of the workpiece W to be impregnated with ultraviolet rays. FIG. 13 schematically shows a state in which the upper surface resin curing process is being performed. In the example shown in FIG. 13, the ultraviolet irradiation device 900 irradiates the upper surface of the part of the workpiece W to be impregnated with ultraviolet rays (see arrow R13). As a result, the upper part (mainly the upper surface part) of the liquid resin material M0 impregnated into the part of the workpiece W to be impregnated is cured. Note that the ultraviolet irradiation device 900 may be the same as the ultraviolet irradiation device 900 used in the outer diameter side resin curing process described above, or may be different.

The ultraviolet irradiation device 900 preferably irradiates the upper surface of the part of the workpiece W to be impregnated with ultraviolet rays over the entire circumference. Thereby, the liquid resin material M0 in the upper portion can be cured over the entire circumference of the region to be impregnated. In this case, the workpiece W may be rotated around the central axis I, or the ultraviolet irradiation device 900 may be rotated. Alternatively, a plurality of ultraviolet irradiation devices 900 may be disposed above the workpiece W in a circumferentially distributed manner.

The ultraviolet irradiation device 900 is preferably positioned with respect to the workpiece W so that the optical axis 901 is substantially perpendicular to the upper surface of the part of the workpiece W to be impregnated. That is, the ultraviolet irradiation device 900 is preferably positioned with respect to the workpiece W so that the optical axis 901 is located within a substantially vertical plane. Here, "approximately" is a concept that includes an error of 10% or less, for example. Further, the ultraviolet irradiation device 900 is preferably positioned with respect to the workpiece W such that the optical axis 901 passes through the part of the workpiece W to be impregnated, and more preferably, the optical axis 901 is located at the diameter of the part of the workpiece W to be impregnated. It is positioned relative to the workpiece W so as to pass near the center of the directional range (range from the innermost radial position to the outermost radial position). In this case, the liquid resin material M0 in the upper part of the part of the workpiece W to be impregnated can be efficiently hardened.

In this manner, according to this embodiment, the workpiece W is in an upward orientation, and the upper portion (axial end portion) of the liquid resin material M0 impregnated into the region to be impregnated is hardened. Therefore, when the upper surface resin hardening process is performed on the workpiece W pulled up from the tank 600 while it is in a downward position (that is, when the upper surface resin hardening process is performed simultaneously with the outer diameter side resin hardening process described above), This can reduce the inconvenience of leaking. Specifically, when the resin curing process is performed on the lower surface of the part to be impregnated with the workpiece W pulled up from the tank 600 while it is in a downward position, the liquid resin material M0 impregnated into the part of the workpiece W to be impregnated is However, there is a risk that it will sag downward and harden due to its own weight. That is, there is a possibility that the liquid resin material M0 may be hardened into an icicle shape. On the other hand, according to this embodiment, since the upper surface resin curing process is performed in the upward position as described above, such inconvenience can be reduced.

In addition, according to this embodiment, by hardening the upper part (axial end) of the liquid resin material M0 impregnated into the region to be impregnated, the corner of the rectangular cross section of the joint 40 (see FIG. 5, below) is cured. , referred to as "joint edge 122"), a thin film of liquid resin material M0 can be formed thereon. That is, even on the joint edge 122 where it is difficult to form the liquid resin material M0 due to the influence of wettability around the coil piece 52, a film of the liquid resin material M0 can be formed, although it is relatively thin. The joint edge 122 on which the film of the liquid resin material M0 is formed has high wettability due to the film. In this way, the wettability of the joint edge 122 (the wettability of the liquid resin material M0) can be increased. As a result, in the subsequent second dipping step (described later), the required thickness of the insulation coating (cured product of liquid resin material M0) on the joint edge 122 of the coil piece 52 can be easily ensured. That is, in the second dipping step, a relatively thick film can also be formed on the joint edge 122 using the film of the liquid resin material M0 formed in the first dipping step as a base. This point will be explained again when explaining the second dipping step.

Next, in this manufacturing method, the workpiece W is turned upside down, and the inner diameter side resin curing step (irradiation step) is performed in which the liquid resin material M0 is cured on the radially inner side surface of the part to be impregnated. example) (step S218). Hereinafter, the resin curing process related to the inner diameter side resin curing process will also be referred to as "inner diameter side resin curing process" to distinguish it from the above-mentioned outer diameter side resin curing process and upper surface resin curing process.

In this embodiment, the inner diameter side resin curing process includes irradiating ultraviolet rays to the radially inner side surface of the part of the workpiece W to be impregnated. FIG. 14 schematically shows a state in which the inner diameter side resin curing process is being performed. In the example shown in FIG. 14, the ultraviolet irradiation device 900 irradiates the radially inner side surface of the part to be impregnated of the workpiece W with ultraviolet rays (see arrow R14). As a result, the radially inner portion (mainly the surface portion) of the liquid resin material M0 impregnated into the part of the workpiece W to be impregnated is hardened. Note that the ultraviolet irradiation device 900 may be the same as the ultraviolet irradiation device 900 used in the above-described upper resin curing process.

The ultraviolet irradiation device 900 preferably irradiates the radially inner side surface of the part of the workpiece W to be impregnated with ultraviolet rays over the entire circumference. Thereby, the liquid resin material M0 in the radially inner portion can be cured over the entire circumference of the region to be impregnated. In this case, the inner diameter side resin curing process may be performed sequentially in parallel with the top resin curing process. Specifically, the upper surface resin curing process and the inner diameter side resin curing process may be performed at once for each divided circumferential range of the entire circumference of the impregnation target region of the workpiece W. Alternatively, the inner diameter side resin curing process may be performed before the top resin curing process. In this case, the inner diameter side resin curing process may be performed simultaneously with or before the outer diameter side resin curing process.

The ultraviolet irradiation device 900 is preferably positioned with respect to the workpiece W so that the optical axis 901 is substantially perpendicular to the radially inner side surface of the part of the workpiece W to be impregnated. That is, the ultraviolet irradiation device 900 is preferably positioned with respect to the workpiece W so that the optical axis 901 is located within a substantially vertical plane. Here, "approximately" is a concept that includes an error of 10% or less, for example. Further, the ultraviolet irradiation device 900 is preferably positioned with respect to the workpiece W such that the optical axis 901 passes through the region of the workpiece W to be impregnated, and more preferably, the optical axis 901 is the axis of the region of the workpiece W to be impregnated. It is positioned relative to the workpiece W so as to pass near the direction center. In this case, the liquid resin material M0 in the upper part of the part of the workpiece W to be impregnated can be efficiently hardened.

However, depending on the size of the ultraviolet irradiation device 900 and the space inside the workpiece W in the radial direction, the ultraviolet irradiation device 900 may be attached to the radially inner side surface of the part of the workpiece W to be impregnated, as shown in FIG. , the optical axis 901 may be positioned relative to the work W in such a manner that the optical axis 901 intersects in an oblique direction. In this case, one of the inner diameter side resin curing treatment and the upper surface resin curing treatment may serve as the other.

When the inner diameter side resin curing process (step S218) by the inner diameter side resin curing process is completed, the insulation coating process for that time is completed.

Next, the present manufacturing method determines whether the number of times the insulation coating process has been performed on one workpiece W has reached a predetermined number of times (in this example, two times as an example) (step S220). Such a determination may be realized by a person or by image processing or the like. If the determination result is "YES", proceed to the next step; otherwise, the steps from step S206 to step S218 are similarly performed in order to perform the second insulation coating step. FIG. 15 schematically shows the workpiece W that has been turned upside down in step S206 to face downward in the second insulation coating process. After that, the workpiece W undergoes a second dipping process and the like.

The second insulation coating step may be exactly the same as the first insulation coating step. In this case, for example, control of the manufacturing equipment can be simplified.

However, the second insulation coating step is preferably different from the first insulation coating step in at least the dipping step. Specifically, in the dipping step in the second insulation coating step, the number of parts to be impregnated is reduced compared to the dipping step in the first insulation coating step. That is, the region to be impregnated in the second dipping step may be a part (part on the axial end side) of the region to be impregnated in the first dipping step. In this case, the region to be impregnated in the second dipping step may be the minimum region including the joint edge 122 of the coil piece 52. Thereby, an insulating coating (cured product of liquid resin material M0) having a necessary function can be efficiently formed using a relatively small amount (eg, minimum) of liquid resin material M0.

FIG. 15 schematically shows a range Q15 to which the impregnation target part in the second insulation coating process belongs, with respect to the range (hatched area M1) of the liquid resin material M0 impregnated into the workpiece W in the first insulation coating process. is shown.

In this manner, in this embodiment, the insulation coating process is performed multiple times (in this embodiment, twice as an example). This makes it possible to ensure the necessary thickness of the insulation coating (cured product of liquid resin material M0) on the joint edge 122 of the coil piece 52.

Specifically, FIG. 16 schematically shows the workpiece W in an upward posture after the second insulation coating process is completed. In FIG. 16, the range of the liquid resin material M0 formed in the first insulation coating process (hatched area M1) and the range of the liquid resin material M0 formed in the second insulation coating process are shown in the hatched area M2. Shown schematically. In addition, in FIG. 16 (the same applies to FIG. 18 etc. described later), for convenience of explanation, only the axial end portion of the coil end portion 114A of the stator coil 114 is schematically illustrated without omitting it.

In the first insulation coating step, a thin film of liquid resin material M0 can be formed on the joint edge 122 of the coil piece 52, as schematically shown in the hatched area M1. In this case, the thickness of the thin film of the liquid resin material M0 on the joint edge 122 is determined by the insulating coating (the thickness of the liquid resin material M0) because the wettability of the joint edge 122 (the wettability of the corner of the linear conductor) is low. The thickness is significantly smaller than the required thickness of the cured product). However, even if the thin film of liquid resin material M0 on joint edge 122 is relatively thin, it can increase the wettability of joint edge 122 with liquid resin material M0. Therefore, during the dipping step in the second insulation coating step, the liquid resin material M0 on the joint edge 122 is likely to adhere. That is, in the second insulation coating step, as schematically shown in the hatched area M2, a further film of the liquid resin material M0 can be formed with a relatively large thickness on the joint edge 122 of the coil piece 52. In this way, it is possible to ensure the necessary thickness of the insulating coating (cured product of the liquid resin material M0) even for the joint edge 122 of the coil piece 52 with low wettability.

When the second insulation coating step is completed, the present manufacturing method includes a heating step (an example of a curing step) of heating the workpiece W so that the liquid resin material M0 in the entire workpiece W is hardened (step S222). This heating step has the function of completely hardening the portion of the liquid resin material M0 that has not been hardened in the various resin curing steps described above (for example, the portion inside the surface). The heating method in the heating step is arbitrary, and may be realized by placing the workpiece W in a furnace, for example. The liquid resin material M0 impregnated into the impregnated region of the workpiece W including the impregnated region is completely cured by being heated. As a result, an insulating coating of the liquid resin material M0 is formed on the stator coil 114.

The posture of the workpiece W in the heating step is arbitrary, but preferably is a downward posture as schematically shown in FIG. 17. Note that FIG. 17 schematically shows a plurality of workpieces W being subjected to a heating process while being arranged side by side in a downward posture. Note that although FIG. 17 schematically shows how a part of the workpiece gripping section 1001 of the manufacturing apparatus holds a plurality of workpieces W, the workpieces W are such that the end surface of the stator core 112 is on the top surface of the table (not shown). It may be supported by a stand in such a manner that it abuts on the base. In addition, in FIG. 17, as an example, heat is radiated to the workpiece W from below (see arrow R17), but the direction of heat radiation is arbitrary.

By the way, in the heating step, in the case of the upward orientation, the liquid resin material M0 that is in the middle of being cured before being completely cured may drip down to the stator core 112 due to its own weight (see arrow R16 in FIG. 16). In this case, it is necessary to separately remove the liquid resin material M0 attached to the stator core 112 using a scraper or the like.

On the other hand, in the case of the downward attitude, even if the liquid resin material M0 that is in the middle of hardening before being completely hardened moves downward under its own weight, it will not reach the stator core 112. In addition, the portion of the liquid resin material M0 that has been cured by the outer diameter side resin hardening treatment, the upper surface resin hardening treatment, and the inner diameter side resin hardening treatment (see C-shaped range 1800 when viewed from the direction in FIG. 18) is “lower lid”. By functioning as ", the possibility that the dripping liquid resin material M0 becomes icicle-shaped can be reduced. FIG. 18 shows the downward movement of the liquid resin material M0 in the middle of curing, as schematically indicated by an arrow R19. The downward movement of the liquid resin material M0 in the middle of curing is stopped by the portion of the liquid resin material M0 that has been cured by the outer diameter side resin hardening process, the upper surface resin hardening process, and the inner radius side resin hardening process. This can prevent inconveniences that may occur when the heating process is performed in a downward position.

In this manner, according to the present embodiment, by performing the heating process in a downward position, the liquid resin material M0 is prevented from dripping onto the stator core 112, and the outer diameter side resin hardening process, the upper surface resin hardening process, and the inner diameter side resin hardening process are performed. The "lower lid" function of the portion of the liquid resin material M0 that has been cured in the side resin curing process can reduce the icicle-like hardening of the liquid resin material M0 that drips downward.

In order to effectively enhance the "lower lid" function, it is desirable to perform all of the outer diameter side resin hardening treatment, the upper surface resin hardening treatment, and the inner diameter side resin hardening treatment. Only the resin curing process and/or the inner diameter side resin curing process may be omitted.

In addition, according to this manufacturing method, one heating step is performed for two insulation coating steps as described above, so energy consumption (and The associated carbon dioxide emissions) can be reduced. Therefore, according to the present manufacturing method, the thickness of the insulation coating of the liquid resin material M0 can be efficiently increased.

In addition, when a heating process is performed for each insulation coating process, there may be discontinuity between the insulation coating of the liquid resin material M0 formed in the first time and the insulation coating of the liquid resin material M0 formed in the second time. However, according to the present manufacturing method, such boundaries can be eliminated and the strength of the entire insulation coating of the liquid resin material M0 can be increased. That is, in this manufacturing method, the viscosity of the liquid resin material M0 impregnated twice decreases during the heating process and becomes a single layer, so there is no discontinuous boundary (separation of layers) in the insulation coating and the strength is improved. .

Next, with reference to FIG. 19, a cooling structure suitable for the rotating electrical machine 1 incorporating the rotating electrical machine stator 10 manufactured by the present manufacturing method will be described.

FIG. 19 is a diagram schematically showing an example of a cooling structure, and is a diagram schematically showing a part of the cross-sectional structure of the rotating electrical machine 1. As shown in FIG.

In the example shown in FIG. 19, oil is supplied to coil end portions 114A at both axial ends of the stator coil 114 from the radially outer side and the radially inner side. Specifically, the oil (see arrow R20A) supplied to the in-case oil passage 60 of the case 2 is supplied to the radially outer side surface of the coil end portion 114A via the oil hole 62 penetrating radially inward. (see arrow R20). Note that the oil hole 62 may be arranged on the upper side in the vertical direction so that dripping of oil by gravity is promoted. Further, the oil supplied to the axial oil passage 64 of the rotor shaft 112A (see arrow R21A) is supplied to the radially inner side surface of the coil end portion 114A through the oil hole 66 penetrating radially outward. (see arrow R21).

According to this manufacturing method, as described above, the coil end portion 114A of the stator coil 114 is provided with an insulating coating of the liquid resin material M0. The portions of the stator coil 114 that are coated with the insulating coating of the liquid resin material M0 have lower thermal conductivity than the portions that are not coated with the insulating coating (that is, the portions where the insulating film 130 is the surface). Therefore, if the exposed range of the radially outer side surface of the coil end portion 114A that is not covered by the insulating coating of the liquid resin material M0 becomes unnecessarily narrow, the cooling performance by the oil from the oil holes 62 described above will be unnecessarily reduced. There is a risk of Similarly, if the exposed range of the radially inner side surface of the coil end portion 114A that is not covered by the insulating coating of the liquid resin material M0 becomes unnecessarily narrow, the cooling performance of the oil from the oil holes 66 described above will deteriorate. There is a risk.

In this regard, according to the present manufacturing method, as described above, the radially outer portion of the liquid resin material M0 impregnated into the region to be impregnated by the outer diameter side resin curing process is cured while facing downward. Even if the workpiece W is subsequently placed in an upward position, the liquid resin material M0 on the radially outer side does not drip downward. This can reduce the possibility that the exposed range of the radially outer side surface of the coil end portion 114A that is not covered with the insulating coating of the liquid resin material M0 will become unnecessarily narrow. As a result, the cooling performance of the coil end portion 114A by the oil from the oil hole 62 described above can be effectively enhanced.

Note that in the above-described embodiment, the inner diameter side resin curing process is performed on the workpiece W in an upward posture, but similarly to the outer diameter side resin curing process, it may also be performed on the workpiece W in a downward posture. good. In this case, the inner diameter side resin curing process may be performed in parallel at the same time as the outer diameter side resin curing process. In this case, the radially inner portion of the liquid resin material M0 impregnated into the target region by the inner diameter side resin curing process is cured while facing downward, so even if the workpiece W is later turned upward, the diameter The liquid resin material M0 on the inside in the direction does not drip downward. This can reduce the possibility that the exposed range of the radially inner side surface of the coil end portion 114A that is not covered with the insulating coating of the liquid resin material M0 will become unnecessarily narrow. As a result, the cooling performance of the coil end portion 114A by the oil from the oil hole 66 described above can be effectively enhanced.

Next, with reference to FIG. 20 and subsequent figures, a further preferred configuration of the above-described present manufacturing method will be described.

FIG. 20 is an explanatory diagram of a preferred method related to the dipping step (step S208). FIG. 20 schematically shows a part of the workpiece W together with the tank 600 at the start of the dipping step in the first insulation coating step. FIG. 21 is an explanatory diagram of the effect of the method shown in FIG. 20, and schematically shows a state in which part Q20 of FIG. 20 has entered the liquid resin material M0 of the tank 600. FIG. 22 is an explanatory diagram of inconveniences that may occur in the immersion process according to a comparative example. 23 and 24 are explanatory diagrams of other inclined postures.

In the immersion step, the workpiece W is preferably immersed in the liquid resin material M0 in the tank 600 in an inclined position. The tilted posture refers to a state in which the angle α (see FIG. 20) of the axial direction of the stator core 112 with respect to the perpendicular line I3 is different from 0 degrees, when the perpendicular line I3 to the liquid level of the liquid resin material M0 in the tank 600 is used as a reference. means attitude. The angle α is arbitrary, but may be, for example, 5 degrees or more. In the following, for the sake of comparison, the posture of the workpiece W in which the angle α=0 is also referred to as the upright posture.

By the way, the part of the work W to be impregnated is formed by the coil piece 52, the bus bar, etc., and may have a planar part extending perpendicularly to the central axis I. Such a plane portion is formed by a portion of the coil piece 52, a portion of the neutral point bus bar 59, and the like. Such a flat portion tends to cause air to accumulate below the workpiece W when the workpiece W is immersed in the tank 600 of the liquid resin material M0 in an upright position. FIG. 22 schematically shows air (bubbles) B22 that accumulates below the workpiece W when the workpiece W is immersed in the tank 600 of the liquid resin material M0 in an upright position. When the end face of the part of the workpiece W to be impregnated is covered with the liquid resin material M0 while the air B22 is attached to the lower part of the workpiece W, a cavity is created in the liquid resin material M0, and after the liquid resin material M0 hardens, an insulating coating ( This may cause voids in the resin mold.

On the other hand, when the workpiece W is immersed in the tank 600 of the liquid resin material M0 in an inclined position as shown in FIG. 20, the air below the workpiece W ( The bubbles) B21 rise along the oblique plane portion 591 (in FIG. 21, the plane portion 591 of the neutral point bus bar 59). That is, air that may accumulate below the workpiece W can be reduced or eliminated. In this way, according to the method shown in FIG. 20, it is possible to reduce cavities in the liquid resin material M0 in the region to be impregnated that may occur when the workpiece W is immersed in the tank 600 of the liquid resin material M0. . As a result, voids that may occur within the insulation coating (resin mold) after curing can be reduced or eliminated.

Here, in the inclined position shown in FIG. 21, the bubble B21 is raised toward the outside in the radial direction, but for example, as shown in FIG. 23, the bubble B23 is raised toward the inside in the radial direction (see arrow R23). A tilted posture may be set. Alternatively, as shown in FIG. 24, an inclined posture may be set in which the bubble B24 is raised in the circumferential direction (see arrow R24).

In this manner, the highest circumferential position of the workpiece W in the inclined position may be appropriately determined according to the position, shape, etc. of the planar portion so that air bubbles can easily rise. In this case, the highest circumferential position of the workpiece W in the inclined position may be set, for example, so that the length of the flat portion along which the bubbles follow when rising (the moving distance of the bubbles) becomes short. Specifically, when the planar portion has a longitudinal direction and a transverse direction, the inclined posture of the workpiece W is such that the inclination angle of the planar portion with respect to the liquid level of the liquid resin material M0 is shorter than the angle along the longitudinal direction. The angle along the hand direction may be determined to be larger. In this case, since the bubbles rise along the transverse direction, it is possible to shorten the length of the plane portion along which the bubbles travel (distance traveled by the bubbles) when rising. In other words, it is possible to realize an inclined posture in which air bubbles can easily escape.

In the dipping process according to the method shown in FIG. 20, the workpiece W is preferably changed in posture from an inclined posture to an upright posture after the plane portion thereof reaches below the liquid level of the liquid resin material M0 in the tank 600. That is, the final posture of the workpiece W in the dipping step is preferably an upright posture. In this case, since the immersion depth in the workpiece W is approximately the same at each position in the circumferential direction (that is, the formation range of the insulating coating of the liquid resin material M0 is approximately the same at each position in the circumferential direction), product management becomes easier.

In this way, when the immersion depth of the workpiece W in the immersion process is approximately the same at each position in the circumferential direction, in order to prevent the immersion depth from becoming unnecessarily large, the inclined position is such that the planar portion is lower than other positions in the circumferential direction. It may be set so that it is immersed first (so that it reaches below the liquid level first). In this case, it is advantageous in that the immersion depth is unlikely to increase even if the tilted position is changed to the upright position when most of the planar portion is immersed. For example, the inclined position shown in FIG. 23 is more advantageous than the inclined position shown in FIG. 21 in that the immersion depth is less likely to increase. Therefore, an inclined posture may be adopted in which the circumferential range in which the neutral point bus bar 59 having the planar portion 591 extends is lower than other circumferential ranges.

The method shown in FIG. 20 is preferably implemented in each dipping step when the insulation coating step is performed multiple times on one workpiece W, but it may be performed only in some of the dipping steps. Good too.

FIG. 25 is an explanatory diagram of a preferred method for the dipping step (step S208) in the second insulation coating step. FIG. 25 schematically shows a part of the workpiece W in an inclined position during the dipping step in the second insulation coating step, together with the tank 600. FIG. 26 is an explanatory diagram of inconveniences that may occur in the immersion process according to a comparative example.

In the following description of the second insulation coating step, unless otherwise specified, the region to be impregnated on the workpiece W means the region to be impregnated in the dipping step in the second insulation coating step. In addition, below, the dipping step in the first insulation coating process (an example of the first impregnation process) is also referred to as the "first dipping process", and the dipping process in the second insulation coating process (an example of the second impregnation process) is also referred to as the "first dipping process". ) is also referred to as the "second dipping step."

In the second immersion step, the workpiece W is preferably partially immersed in the liquid resin material M0 of the tank 600 in two or more types of inclined postures before being immersed entirely. The tilted posture means a posture of the workpiece W in which the above-mentioned angle α (see FIG. 20) is significantly larger than zero. The angle α in the second dipping step is arbitrary, but may be larger than the angle α described above with reference to FIG. Two or more types of inclined postures can be formed by moving the workpiece W.

Two or more types of inclined postures include postures in which the angle α is the same but the highest circumferential position of the workpiece W is different. That is, in the inclined position, only a part (a part in the circumferential direction) of the part of the workpiece W to be impregnated is separated upward from the liquid surface of the liquid resin material M0 in the tank 600, but the circumferential position of the part is in the inclined position. varies depending on the type of In addition, in a modified example, two or more types of tilted postures may be accompanied by a difference in angle α.

By the way, when the insulation coating process is performed in two or more times in order to ensure the thickness of the insulation coating (for example, the thickness of the insulation coating on the joint edge 122) as in this manufacturing method, the When the workpiece W is immersed in the tank M0 of the liquid resin material 600, the lower part of the workpiece W is Air tends to accumulate in the area. Note that, since the liquid resin material M0 has no air permeability, the liquid resin material M0 impregnated before the previous time inhibits air escape. Such cavities can cause voids in the insulation coating (resin mold) after curing.

FIG. 26 schematically shows air (bubbles) B26 that accumulates below the workpiece W due to the uneven shape of the liquid resin material M0 impregnated before the previous time. When the end face of the part of the workpiece W to be impregnated is covered with the liquid resin material M0 while the air B26 is attached to the lower part of the workpiece W, a cavity in the liquid resin material M0 is formed as in the case described above with reference to FIG. This may cause voids in the insulation coating (resin mold) after the liquid resin material M0 is cured.

On the other hand, when the workpiece W is immersed in the tank M0 of the liquid resin material 600 in an inclined position as shown in FIG. becomes easier to invade. That is, air that may accumulate below the work W due to the recess 70 can be reduced or eliminated. In this way, according to the method shown in FIG. 25, it is possible to reduce cavities in the liquid resin material M0 in the region to be impregnated that may occur when the workpiece W is immersed in the tank M0 of the liquid resin material 600. . As a result, voids that may occur within the insulation coating (resin mold) after curing can be reduced or eliminated.

Here, the unevenness of the axial end face of the workpiece W (the uneven form of the liquid resin material M0 applied to the workpiece W in the first immersion step) that can cause the voids described above is caused by the fact that the plurality of coil pieces 52 are connected to the stator core. This tends to occur when four or more slots 112 are installed in each slot 23 in such a manner that they overlap in the radial direction. In this case, in the joining process described above, when two radially adjacent joint parts 40 are set as one set and a plurality of sets are joined in the radial direction, between the plurality of sets of joint parts 400 in the radial direction, This is because a recess 70 (see FIG. 25) that is recessed inward in the axial direction is likely to be formed. Although FIG. 25 shows one recess 70 between two sets of joints 400 in the radial direction, if there are three or more sets, two or more recesses 70 will be formed. The recess 70 basically extends over the entire circumference of the workpiece W in the circumferential direction.

In this regard, in the second immersion step, if the workpiece W is partially immersed in the liquid resin material M0 of the tank 600 in two or more types of inclined postures before being completely immersed, each position in the circumferential direction The liquid resin material M0 in the tank 600 can enter into the recess 70 in the manner shown in FIG. In particular, when the recess 70 is continuous in the circumferential direction, the air within the recess 70 in the circumferential range that enters the liquid resin material M0 of the tank 600 in one type of inclined posture is directed upwardly than the liquid resin material M0. It can escape to the outside of the liquid resin material M0 via the recessed portion 70 located in the other circumferential direction range. That is, air in the recess 70 that is below the liquid level can escape to the outside via another recess 70 that is above the liquid level.

The greater the number of two or more types of inclined postures applied to one workpiece W in the second dipping step, the more the amount of air that may remain in the recess 70 at each position in the circumferential direction can be reduced. It is advantageous in this respect. On the other hand, the greater the number of two or more types of tilted postures, the more disadvantageous it becomes from the viewpoint of CT.

Therefore, the number of two or more types of inclined postures applied to one workpiece W in the second dipping step is preferably three or more, and for example, as described below with reference to FIG. 27. The number may be eight, as shown in FIG.

FIG. 27 is an explanatory diagram of preferred examples of eight types of tilted postures. In FIG. 27, the workpiece W is schematically shown in a top view along with circumferential ranges SC1 to SC8 of the workpiece W, which are equally divided into eight parts. In this case, eight circumferential ranges SC1 to SC8 are set at equal pitches.

In this case, the eight types of tilted postures include the first type of tilted posture in which the circumferential range SC1 of the workpiece W is most immersed in the liquid resin material M0 of the tank 600 (that is, located furthest below the liquid level); , a second type of tilted posture in which the circumferential range SC2 of the workpiece W is most immersed in the liquid resin material M0 of the tank 600, and a third type of tilted posture to an eighth type of tilted posture related to similar SC3 to SC8. including.

Although the order in which the eight types of inclined postures are formed is arbitrary, for example, they may be formed in clockwise order in FIG. 27 from the first type of inclined posture to the eighth type of inclined posture. In this case, the air within the recess 70 can be expelled to the outside in a clockwise circumferential direction. In this case, in the eighth type of inclined posture, although the air in the recess 70 cannot be expelled in the circumferential direction, it is possible to minimize the air in the recess 70 by, for example, increasing the angle α. can. Note that, for example, if the configuration of the recess 70 in the circumferential range where the neutral point bus bar 59 is arranged is different from other circumferential ranges, the circumferential direction range SC8 related to the eighth type of tilted posture is the same as that of the neutral point bus bar 59. It may be made to coincide with the circumferential range in which is arranged.

In this way, by changing the inclination posture so that the eight circumferential ranges SC1 to SC8 are immersed in equal circumferential ranges, the formation range and thickness of the insulating coating of the liquid resin material M0 can be changed along the circumferential direction. Product management becomes easier because the results are uniform.

Note that in the second dipping step according to the method shown in FIG. 27, the workpiece W may be changed in posture from the tilted posture to the upright posture after the eighth type of tilted posture. In this case, since the formation range and thickness of the insulating coating of the liquid resin material M0 are approximately the same at each position in the circumferential direction, product management becomes easy.

Although each embodiment has been described in detail above, it is not limited to a specific embodiment, and various modifications and changes can be made within the scope of the claims. It is also possible to combine all or a plurality of the components of the embodiments described above.

For example, in the embodiments described above, as a preferred embodiment, the resin curing process on the outer diameter side is performed, but the resin curing process on the inner diameter side may be performed instead of the resin curing process on the outer diameter side.
In addition, in the above embodiment, instead of the first dipping step, the step of impregnating the target part of the workpiece W with the liquid resin material M0 by dropping the liquid resin material M0 onto the target part of the workpiece W ( Another example of the first impregnation step) may be performed.

40... Joint part (tip part), 52... Coil piece, 112... Stator core, 114... Stator coil, 70... Recessed part, 600... Tank, W... Work, M0 ...Liquid resin material

Claims (6)

a mounting step of mounting a plurality of coil pieces forming a stator coil on a stator core to form a work;
After the mounting step, a joining step of joining the respective tip portions of one of the coil pieces and the other of the coil pieces at one end in the axial direction of the work;
After the joining step, a first impregnation step of impregnating an annular impregnation target region of the work including the joint between the tips of the workpiece with a liquid resin material;
After the first impregnation step, a second impregnation step of immersing the workpiece in a tank of liquid resin material so that at least a part of the region to be impregnated in the first impregnation step is immersed;
After the second impregnation step, a curing step of curing the liquid resin material impregnated into the region to be impregnated,
In the second impregnation step, by moving the workpiece, a tilted posture of the workpiece is changed so that a part of the entire circumference of the region to be impregnated is away from the surface of the liquid resin material in the tank. A method for manufacturing a stator for a rotating electrical machine, the method comprising forming a stator twice or more in a manner in which the directional position changes. 2. The method for manufacturing a stator for a rotating electrical machine according to claim 1, wherein in the second impregnation step, the tilted posture is formed two or more times in such a manner that the circumferential positions of the portions are arranged at equal pitches along the circumferential direction. According to claim 1 or 2, in the second impregnation step, the inclined posture is formed three or more times in such a manner that each circumferential portion of the region to be impregnated is immersed in the liquid resin material of the tank at least once. A method for manufacturing a stator for a rotating electric machine. Liquid resin material has the property of being hardened by irradiation with ultraviolet rays.
The rotary electric machine according to any one of claims 1 to 3, further comprising an irradiation step of irradiating the region to be impregnated with ultraviolet rays after the first impregnation step and before the second impregnation step. Stator manufacturing method. The plurality of coil pieces in the workpiece are installed in each slot of the stator core in such a manner that four or more coil pieces overlap in the radial direction,
Manufacturing a stator for a rotating electrical machine according to any one of claims 1 to 4, wherein in the joining step, two radially adjacent tip portions are considered as one set, and a plurality of sets are joined in the radial direction. Method. The rotating electric machine according to claim 5, wherein in the work immediately before the second impregnation step, the liquid resin material has a concave portion in a radial direction between the plurality of sets of tip portions concave inward in the axial direction. stator manufacturing method.