Rotary electric machine and method for manufacturing rotary electric machine

Abstract

According to the present invention, the infiltration of moisture into a slot portion of a stator is blocked and the insulation reliability of a rotary electric machine is improved. This rotary electric machine, having a stator 10 and a rotor that can rotate about a rotary shaft, includes a cylindrical waterproof member 50 provided on the stator 10, which faces the rotor with a gap therebetween, so as to cover the entire inner circumferential surface of the stator. The cylindrical waterproof member 50 is formed as a single seamless body from a first stator core 11a to a second stator core 11b and molded to resins 71 at end sections (51a, 52) on both sides adjacent to coil ends to waterproof slots of the stator 10.

Description

Rotating electric machine and method of manufacturing the same

[0001] The present invention relates to a rotating electrical machine, and more particularly to preventing moisture from entering a coil portion from the inner peripheral surface of a stator.

[0002] While there is a demand for miniaturization of rotating electrical machines, further improvements in electrical insulation are also required. To miniaturize stators, a structure that increases the winding space factor and achieves high power density is effective. For this reason, a stator structure consisting of segment coils using rectangular wire with a flat cross section is used as the conductor, rather than the general round wire.

[0003] When constructing a stator coil using rectangular wire, multiple divided segment coils are connected to each other. In the in-slot connection method, the segment coil is roughly U-shaped and has a pair of straight sections and an inclined section connecting them, with the two straight sections each housed in a slot in the stator core. These straight sections are inserted into the slot from both end faces of the stator core in the direction of the rotation axis and connected within the slot. The inclined sections connecting the pair of straight sections of the segment coil are structured to protrude outward in the direction of the rotation axis from both axial ends of the stator core.

[0004] A technology related to this in-slot connection method is known, as described in Patent Document 1. The rotating electric machine described in Patent Document 1 uses a stator core formed by laminating amorphous thin magnetic steel sheets and split into two at the axial center. The first split stator is manufactured by inserting the straight sections of the segment coils into the slots of one of the split stator cores via bobbins, and fixing the coil ends to a reference position using fixtures or adhesive resin. The second split stator is manufactured in the same manner. The straight sections of the segment coils of the first and second split stators are connected by press-fitting, and then the entire stator coil is placed in a mold, and the segment coils are then molded with resin. The tips of the legs (ends of the straight sections) of the two connected conductor segments are formed with either a protrusion (convex portion) that protrudes partially in the longitudinal direction or a groove with a recess formed on the tip surface.

[0005] Rotating electric machines can be used as power sources for a variety of devices, including fan drive motors and pump drive motors used in humid environments, and motors in which the interior of the motor is directly cooled with a coolant. These rotating electric machines are susceptible to moisture intrusion through gaps between the laminated cores of the stator or in the terminal box, which can cause insulation problems between the core and the coil. Therefore, adequate waterproofing measures are important. Patent Document 2 discloses a known technology relating to a stator using an in-slot connection method, a stator using a coating layer, and a rotating electric machine.

[0006] JP 2022-49171 A JP 2022-128816 A

[0007] A stator using the in-slot connection method disclosed in Patent Document 1 is manufactured by connecting the ends of the straight sections of the segment coils to be connected within the slots while checking their positions. A split stator using this in-slot connection method can operate with sound electrical characteristics without being affected by moisture when a rotating electric machine is operated in a normal operating environment. On the other hand, when a rotating electric machine is operated in a special high-humidity environment, it is important to take measures to prevent moisture from entering between the laminations of the split stator's laminated core or through tiny gaps between the mold and the core in the central divided section of the inner circumferential surface, so as not to destabilize insulation reliability, such as the insulation resistance between the connections between the ends of the straight sections of the stator core and the segment coils.

[0008] In Patent Document 2, a coating layer is provided on the core surface, etc., via a primer layer to prevent moisture from penetrating through the core surface, etc., of the inner periphery of the stator, for a rotating electric machine used in a high-humidity environment, thereby preventing insulation failure. However, there is a risk that the coating layer may be damaged or peeled off due to contact with the rotor during motor assembly, or due to deterioration during operation. If the coating layer is damaged or peeled off, there is a concern that broken fragments may become the source of driving problems in the motor.

[0009] The present invention has been made in consideration of the above background, and its object is to provide a rotating electric machine having a stator structure that prevents moisture from entering from the inner peripheral surface of the stator and improves insulation reliability. Another object of the present invention is to provide a rotating electric machine in which a waterproof member is provided on the inner peripheral surface of the stator, thereby suppressing damage due to contact with the rotor during assembly, damage due to deterioration over long-term operation of the motor, and peeling of the coating layer. Yet another object of the present invention is to provide a rotating electric machine having a split stator structure, in which an integrally molded cylindrical waterproof member that is longer than the axial length of the entire stator is provided on the inside of the stator.

[0010] To achieve the above object, the present invention provides a rotating electric machine having a stator and a rotor rotatably arranged on the inner periphery of the stator, with a waterproof material (e.g., a cylindrical waterproof member) interposed to cover the entire inner periphery of the stator. The stator is divided into a first stator core and a second stator core. The first stator core has a plurality of slots and segment coils inserted into the slots and having convex portions at their ends. The second stator core has a plurality of slots and segment coils inserted into the slots and having concave portions at their ends. The first stator core and the second stator core have end faces facing each other in the rotational axis direction, and the convex and concave portions, which are the connection portions of the segment coils, are fitted together. The cylindrical waterproof member is arranged from the coil end of the first stator core to the coil end of the second stator core, and is fixed by being embedded in resin at each coil end. The outer peripheral surface of the cylindrical waterproof member is fixed to the resin that fills the gaps in the divided portions and slots of the stator.

[0011] According to another feature of the present invention, a cylindrical waterproof member provided in a rotating electric machine covers the inner peripheral portion of a stator core and is formed as a one-piece molded product having insulating and waterproof properties. One end and the other end of the cylindrical waterproof member in the rotational axis direction are fixed so that all portions in the circumferential direction are embedded in a resin mold. The cylindrical waterproof member is preferably formed as a one-piece unit by injection molding using polyethylene terephthalate material with a heat resistance temperature of 120°C or higher. The wall thickness of the cylindrical portion is preferably less than half the size of the gap between the stator core and the rotor.

[0012] According to another feature of the present invention, a rotating electric machine includes a rotor fixed to a rotating shaft, a stator core disposed on the outer periphery of the rotor with a gap therebetween, and a stator coil wound around slots at predetermined intervals. The stator coil is connected so as to be exposed outward from the end of the stator core in the direction of the rotation axis, and the exposed portion of the stator coil is molded with resin to manufacture the rotating electric machine. During this manufacturing process, an integrated cylindrical waterproof member that covers the inner periphery of the stator core and has insulating and waterproof properties is inserted inside the stator core. Then, resin is formed on one and the other sides of the cylindrical waterproof member in the direction of the rotation axis so as to be embedded in the resin mold, thereby manufacturing the stator. The outer periphery of the rotor and the inner periphery of the cylindrical waterproof member are configured to face each other with a predetermined gap therebetween.

[0013] According to the present invention, the entire inner peripheral surface of the stator core is covered with a cylindrical waterproof member having an integral structure, which prevents moisture from entering the vicinity of the stator coil and improves the insulation reliability of the connection points of the segment coil. Other issues, configurations, and effects will become clear from the description of the following examples.

[0014] 1 is a perspective view of a rotor 5 and a stator 10 of a rotating electric machine 1 according to a first embodiment of the present invention. FIG. 2 is a side view showing the stator 10 of the rotating electric machine 1 according to the first embodiment of the present invention in a state before molding. FIG. 3 is an exploded perspective view for explaining a method of assembling the stator 10 of FIG. 2, showing the state before the first coil segment 30 and the second coil segment 40 made of rectangular wire are inserted into the stator cores 11a, 11b. FIG. 4 is a perspective view of the stator core 11 of FIG. 1. FIG. 5 is an axial projection view of the stator core 11 (before the bobbin 65 is attached). FIG. 6 is a perspective view showing the bobbin 65 alone. FIG. 7 is a perspective view of the bobbin 65 alone as seen from another angle. FIG. 8 is an axial projection view of the stator core 11 after the bobbin 65 is attached. FIG. 9 is a side view showing the state after all of the coil segments 30, 40 made of rectangular wire have been inserted into the stator core during assembly of the stator 10. FIG. 11 is a cross-sectional view of the rotating electric machine 1, showing the state in which the cylindrical waterproofing member 50 according to this embodiment is attached to the stator core 11. 9A is a partial cross-sectional view showing the positional relationship between the cylindrical waterproofing member 50 and the mold 90 in FIG. 6A. FIG. 7A is a perspective view of the cylindrical waterproofing member 50 according to this embodiment. FIG. 7B is a cross-sectional perspective view showing the cylindrical waterproofing member 50 attached to the stator core 11. FIG. 7C is a cross-sectional view of the rotating electric machine 1, showing a state after the resin 71 has been filled into the mold 90. FIG. 8A corresponds to the partial cross-sectional view of FIG. 8A, showing a cross section at a position shifted by half a slot in the circumferential direction. FIG. 9B is a diagram showing a manufacturing procedure for the stator core 11 (Step 1). FIG. 9C is a diagram showing a manufacturing procedure for the stator core 11 (Step 2) following FIG. 9A. FIG. 9C is a diagram showing a manufacturing procedure for the stator core 11A according to the second embodiment (Step 1). FIG. 9C is a diagram showing a manufacturing procedure for the stator core 11A following FIG. 10A (Step 2). FIG. 9C is a diagram showing a manufacturing procedure for the stator core 11A following FIG. 10B (Step 3). 10B is a diagram showing a manufacturing procedure of the stator core 11A next to that of FIG. 10C (step 4). FIG.

[0015] A rotating electric machine according to an embodiment of the present invention will be described below with reference to the drawings. The following embodiments are merely illustrative of the present invention, and some omissions and simplifications have been made for clarity of explanation. The present invention can be implemented in various other forms. Unless otherwise specified, each component may be singular or plural. The position, size, shape, range, etc. of each component shown in the drawings may not represent the actual position, size, shape, range, etc., in order to facilitate understanding of the invention. Therefore, the present invention is not necessarily limited to the position, size, shape, range, etc., disclosed in the drawings. When there are multiple components having the same or similar functions, they may be described using the same reference numeral with different subscripts. Furthermore, when it is not necessary to distinguish between these multiple components, the subscripts may be omitted.

[0016] FIG. 1 is a perspective view of a rotor 5 and a stator 10 of a rotating electric machine 1 according to a first embodiment. The rotating electric machine 1 is an internal rotation, radial gap type rotating electric machine, and includes a stator 10 that generates magnetic force using electric power, a rotor 5 that rotates due to the magnetic force generated by the stator 10, a shaft 4 that rotates together with the rotor 5, and a housing 2 (described later in FIG. 11 ) that covers and protects the stator 10 and the rotor 5. The rotor 5, fixed to the shaft 4, rotates inside the substantially cylindrical stator 10. When viewed radially, the inner circumferential surface of the stator 10 and the outer circumferential surface of the rotor 5 are not in contact with each other, and a certain gap is formed in the radial direction. The rotor 5 is formed by including a plurality of permanent magnets (not shown in the figure) that form magnetic poles. The stator 10 includes a stator core 11 (see FIG. 2 described later), and a stator coil 20 (see FIG. 2 described later) is wound around the stator core 11. The coil end portion of the stator coil 20 on the lead-out side that protrudes forward from the stator core 11 is covered with molded resin 71, and a mold cover 19 is attached. The coil end portion of the stator coil 20 that protrudes rearward from the stator core 11 is also covered with molded resin 71.

[0017] FIG. 2 is a side view of the stator 10, showing the state before molding according to this embodiment. The stator core 11 is formed by laminating punched thin electromagnetic steel sheets in the direction of the rotation axis Ax, and has a large number of teeth protruding radially inward from a cylindrical portion on the outer periphery. The spaces between adjacent teeth form slots, and a distributedly wound stator coil 20 is formed in each slot. The stator coil 20 is made of a metal wire with high electrical conductivity, such as copper or aluminum, and its surface is coated with an insulating coating such as an enamel coating or an inorganic coating. The cross section of the metal wire constituting the stator coil 20, perpendicular to the longitudinal direction, is circular or rectangular. In this embodiment, an enameled wire made of soft copper with a rectangular cross section is used.

[0018] The stator core 11 has a total length L in the rotational axis direction and is formed by arranging two divided stator cores, a first stator core 11a and a second stator core 11b, in the axial direction. The axial lengths of the first stator core 11a and the second stator core 11b are approximately equal to L / 2, with the dividing plane of the stator core 11 being near the center. The front side (+Z side) of the stator core 11 is the lead-out side where the lead pieces 21 to 26 of the stator coil 20 are arranged, and the rear side (-Z side) is the opposite lead-out side of the stator coil 20. Once all of the first coil segments 30 and lead pieces 21 to 26 are inserted into the slots 14a of the first stator core 11a, the core end portions are temporarily fixed to the first stator core 11a with temporary fixing resin 71a to prevent movement. Similarly, once all of the second coil segments 40 have been inserted into the slots 14b (see FIG. 3, described later) in the second stator core 11b, they are temporarily fixed with temporary fixing resin 71b to prevent the core end portions from moving from the second stator core 11b. In this state, the first stator core 11a and the second stator core 11b are joined, completing the connection of the stator coil 20. The lead pieces 21 to 26 are also joined to the second coil segments 40. When the stator coil is three-phase, six lead pieces are used, and in the side view of FIG. 2, lead piece 26 overlaps with the same lead piece 24, so only five lead pieces, 21 to 25, are visible.

[0019] 3 is an exploded perspective view illustrating a method for assembling the stator 10 of FIG. 2 in the rotating electric machine 1 according to this embodiment. Each phase of the stator coil 20 of this embodiment is formed not from a single continuous enameled wire, but by connecting multiple divided enameled wires (coil segments 30, coil segments 40). In this specification, the divided coil portions are referred to as "coil segments," and multiple coil segments physically and electrically connected are referred to as a "coil (for one phase)" or "stator coil 20." The stator coil 20 of this embodiment is formed from multiple wave-wound coils.

[0020] The stator coil 20 is mainly formed by first coil segments 30 inserted into the slots 14a from one side of the stator core 11a and second coil segments 40 inserted into the slots 14b from the other side of the stator core 11b. A plurality of first coil segments 30 are inserted into the slots 14a in the direction of arrow 27 from one side (e.g., the front side) of the stator core 11 in the direction of the rotational axis Ax. Opposite to these, a plurality of second coil segments 40 are inserted into the slots 14b in the direction of arrow 28 from the other side (e.g., the rear side) in the direction of the rotational axis Ax. Ends (35, 36, 45, 46) of the first coil segments 30 and the second coil segments 40 are connected within the internal space of the slots 14 (14a, 14b) of the stator core 11. In this embodiment, the ends 35, 36, 45, 46 are connected near the dividing plane.

[0021] As described above, multiple (e.g., six) enameled wires are arranged radially from the inner periphery to the outer periphery in each slot 14a, 14b of the first stator core 11a and the second stator core 11b. The first coil segment 30 is generally U-shaped and includes straight portions 31, 32 housed in the slot 14a and inclined portions 33, 34 protruding from the front end face of the stator core 11 and exposed from the slot so as to extend in a direction intersecting the axial direction of the stator core 11. Convex portions 35, 36 are formed on the other ends of the straight portions 31, 32, respectively, on the open side not connected to the inclined portions 33, 34. The convex portion 36 is a protruding portion formed by removing two side surfaces from the tip end face 36a by a predetermined length to form a rectangular parallelepiped. An enlarged view of the convex portion 36 is shown in the upper right circular frame of FIG. 3 . The shape of the convex portion 35 is identical to that of the convex portion 36. Enameled wire is used for each of the first coil segment 30 and the second coil segment 40. Enameled wire is made of copper wire, and an enamel coating is formed on the outer surface of the copper wire. The enamel coating on the copper wire has the characteristic of not conducting electricity.

[0022] The second coil segment 40 is formed in a roughly U-shape and has straight portions 41, 42 housed in the slots 14b and inclined portions 43, 44 protruding from the other end (rear end face) of the stator core 11 and extending in a direction intersecting the axial direction of the stator core 11, exposed from the slots. Recesses 45, 46 are formed at the open ends of the straight portions 41, 42, respectively, that are not connected to the inclined portions 43, 44. Thus, the basic shape of the second coil segment 40 is similar to that of the first coil segment 30. An enlarged view of the recess 46 is shown in the circled box at the lower right of Figure 3. The shape of the recess 45 is identical to that of the recess 46. The recess 46 has a groove 46b, which is formed by removing a region including the center of the tip end face by a predetermined length in the longitudinal direction. A large number of second coil segments 40 are prepared for assembling the stator coil 20.

[0023] When assembling the stator coil 20, the ends (protrusions 35, 36) of the first coil segment 30 are fitted into the ends (recesses 45, 46) of the second coil segment 40. Joining the coil segments in the stator coil 20 is typically done by welding, crimping, soldering, or the like. However, in this embodiment, the connection is completed by fitting alone, without welding, crimping, soldering, or the like. Although not shown in FIG. 3 , a synthetic resin bobbin 65 (described later in FIGS. 4C and 4D ) is provided within the slot 14. The straight portions 31, 32 of the first coil segment 30 are inserted into the bobbin 65, and the straight portions 41, 42 of the second coil segment 40 are inserted into another bobbin 65.

[0024] Next, the detailed shape of the stator core 11 will be described using Figures 4A to 4E. Figure 4A is a perspective view of the front half of the stator core 11 (the first stator core 11a alone), showing the bobbin 65 attached. However, the stator coil 20 is not wound. Figure 4B is a partial enlarged view from one side (front side) in the rotational axis direction of Figure 4A (however, the bobbin 65 is not attached). As shown in Figure 4B, the stator core 11a has a core-back core 12a formed on the outer periphery. The teeth portion is formed by laminating amorphous metal foil strips cut into trapezoidal shapes and arranging the teeth cores 13a, forming a total of 48 slots 14a in the circumferential direction. In this embodiment, the teeth portion is made of a material (amorphous) different from the material (electromagnetic steel sheet) of the core-back core 12a portion. Note that the teeth cores 13a portion may be made of other materials instead of amorphous. The second stator core 11b (not shown) has the same configuration as the first stator core 11a, and these can be made into common parts. The core-back core 12b, tooth cores 13b, and slots 14b (not shown) have the same shapes as the core-back core 12a, tooth cores 13a, and slots 14a shown in the figure.

[0025] FIG. 4C is a perspective view of the bobbin 65 alone, as viewed from the inner circumferential side, and FIG. 4D is a perspective view of the bobbin 65 alone, as viewed from the outer circumferential side. The bobbin 65 is formed with a length L approximately equal to the length of the first stator core 11a in the rotational axis direction (strictly speaking, the bobbin 65 is longer by the length of the jaws 67 and 68), and a width W equal to the width of the slots 14a and 14b in the circumferential direction. Four insertion holes 66a to 66d are formed inside the bobbin 65, extending radially from the inner to the outer circumferential direction, through which rectangular conductors are inserted parallel to the rotational axis direction (m in number, m = 4 in this case). Partition walls are provided at the boundaries between the insertion holes 66a to 66d, ensuring reliable insulation of each coil piece. Jaws 67 and 68 are provided at both axial ends of the bobbin 65, and function to axially contact the end faces of the teeth cores 13a. The inner circumferential sides of the jaws 67 and 68 are formed with claw-like protruding claw-shaped claws 67a and 68a, respectively, and the stator core 11a is assembled by inserting the bobbin 65 from the radially inner side toward the radially outer side. When all the bobbins 65 are installed in the slots 14a of the stator core 11, the teeth core 13a is constrained not only in the circumferential direction but also in the axial direction. Figure 4E shows the state after the bobbin 65 has been attached from the state shown in Figure 4B. In this manner, the first bobbin 65 made of resin is placed in the slot of the first stator core 11a, and the second bobbin 65 made of resin, which houses multiple second coil segments 40 arranged radially, is placed in the slot of the second stator core 11b.

[0026] FIG. 5 is a side view showing the state after all first and second coil segments 30, 40 have been inserted into the stator cores 11a, 11b during assembly of the stator 10 of this embodiment. Because the stator coil 20 is divisible into one side and the other side along the rotation axis Ax, a large number of first coil segments 30 and lead pieces 21-26 (26 is not shown in the figure) are first inserted into the first stator core 11a. The lead pieces 21-26 are for lead-out and connected to both ends of the regular winding and are formed from flat wire made of the same material as the first and second coil segments 30, 40. The lead pieces 21-26 are connected to the second coil segment 40, and the end connected to the second coil segment 40 has a protrusion (not shown in the figure) similar to the protrusion 36 of the first coil segment 30 (see FIG. 3).

[0027] Once the insertion of the first coil segment 30 and the lead pieces 21 to 26 into all positions of the slots of the first stator core 11a is completed, the exposed portions of the first stator core 11a and parts of the exposed portions of the lead pieces 21 to 26 are temporarily fixed with resin 71a to prevent relative movement of the first stator core 11a. In this state, the protrusions 35, 36 of the first coil segment 30 and the protrusions of the lead pieces 21 to 26 are positioned so as to slightly protrude from the dividing surface side (the other side) of the first stator core 11a.

[0028] Similarly, on the second stator core 11b side, once the bobbins 65 and second coil segments 40 have been inserted into all of the slots 14b, a portion of the second stator core 11b is temporarily fixed with resin 71b to prevent relative movement of the second stator cores 11b. Thereafter, the first stator core 11a and the second stator core 11b are brought closer in the direction of the rotation axis Ax, whereby the protrusions 35 and 36 of the first coil segment 30 shown in Figure 3 and the recesses 45 and 46 of the second coil segment 40 shown in Figure 3 are press-fitted together. Next, the joined stator 10 is housed in a resin mold for final fixing.

[0029] FIG. 6A is a cross-sectional view showing the stator 10 housed in a mold 90. The inner mold 92 shown in FIG. 6B is omitted from FIG. 6A . Here, the stator core 11 and mold 90 are shown cut in half along a cross section including the rotation axis Ax. This process illustrates the stator core 11, temporarily fixed with resin 71a, before the permanent fixing resin 71 (see FIG. 8A , described later) is formed. A cylindrical waterproofing member 50, indicated by a thick line, is inserted into the inner periphery of the stator core 11, and then the permanent fixing resin 71 (see FIG. 8 , described later) is poured in from above under pressure. The coil ends of the multiple first coil segments 30 (portions exposed to the outside from the first stator core 11a) are previously fixed to each other by the temporary fixing resin 71a, and the coil ends of the multiple second coil segments 40 (portions exposed to the outside from the second stator core 11b) are previously fixed to each other by the temporary fixing resin 71b.

[0030] FIG. 6B is a longitudinal cross-sectional view of the right cross-sectional portion of FIG. 6A . However, the cross-sectional position is shifted circumferentially by half a slot, and is a cross-sectional view of a position where the coil segments 30 and 40 are not located. As can be seen in FIG. 6B , the mold 90 includes a cylindrical outer mold 91, an inner mold 92, and a bottom mold 93. The bottom mold 93 and the outer mold 91, and the inner mold 92 and the bottom mold 93 are fixed with a plurality of fixing bolts 96. In other words, the bottom mold 93, the outer mold 91, and the inner mold 92 form a mold structure for pouring the resin 71 shown in FIG. 8A . Here, as shown in FIGS. 6A and 6B , when the stator 10 is placed in the mold 90, a cylindrical waterproofing member 50 is placed between the stator core 11 and the inner mold 92.

[0031] Next, the shape of the cylindrical waterproofing member 50 will be described using FIGS. 7A and 7B . FIG. 7A is a perspective view of the cylindrical waterproofing member 50 according to this embodiment, and FIG. 7B is a cross-sectional perspective view showing the positional relationship between the cylindrical waterproofing member 50 and the stator core 11. As shown in FIG. 7A , the cylindrical waterproofing member 50 has a preformed shape having an outer shape sized to follow the contour of the inner circumferential surface of the stator core 11, i.e., the inner circumferential surface of the teeth core 13 a shown in FIG. 4B . The cylindrical waterproofing member 50 is formed by a cylindrical portion 51 and a flange portion 52 formed to extend radially from the edge of one side (here, the upper side) of the cylindrical portion 51. The cylindrical portion 51 and the flange portion 52 are integrally molded from the same material. Therefore, unlike waterproofing members formed by rolling a flat sheet, there are no seams, which prevents moisture from penetrating from the inner circumferential side to the outer circumferential side of the cylindrical waterproofing member 50.

[0032] The material for the cylindrical waterproofing member 50 is selected from those with low thermal shrinkage and excellent heat resistance, thermal shrinkage, and mechanical properties. Examples include PET (polyethylene terephthalate) resin, PEN (polyethylene naphthalate) resin, PPS (polyphenylene sulfide) resin, PA (polyamide) resin, PEI (polyetherimide) resin, and PI (polyimide) resin. Considering cost, PET resin and PEN resin are particularly preferable. The thickness of the cylindrical waterproofing member 50 is optional, but should be determined appropriately depending on the clearance between the rotor outer diameter and the stator inner diameter of the rotating electrical machine and the mechanical properties required for the manufacturing process.

[0033] In the case of a rotating electrical machine 1 in which the gap between the rotor 5 and the stator 10 is approximately 1.5 mm, the thickness of the cylindrical portion 51 is set to 0.5 mm on the side closer to the flange portion 52 and approximately 0.25 mm near the opening on the opposite side from the flange portion 52. The reason for varying the thickness in this manner is to create a tapered surface in which the inner diameter of the cylindrical waterproofing member 50 becomes smaller as it approaches the flange portion 52. The tapered surface allows the cylindrical waterproofing member 50 to be inserted into the inner mold 92 in a state of tight contact with the outer circumferential surface of the inner mold 92.

[0034] 7B is a diagram showing the state in which the cylindrical waterproofing member 50 is inserted inside the stator core 11. The maximum diameter of the flange portion 52 of the cylindrical waterproofing member 50 is formed larger than the inner diameter of the first stator core 11a, so that it can be fixed so as not to move not only in the radial direction but also on one side in the axial direction (the side opposite to the flange). In addition, the outer diameter D of the portion of the cylindrical waterproofing member 50 near the flange portion 52 is １ The outer diameter D ２ The cylindrical waterproof member 50 is formed slightly smaller than the cylindrical waterproof member 50, making it easier to insert the cylindrical waterproof member 50 inside the stator core 11. In this embodiment, the cylindrical waterproof member 50 has no joints on the inner circumferential side of the stator core 11. Therefore, unlike when a coating material is applied to the inner circumferential surface of the stator core 11, it is possible to effectively avoid phenomena such as the coating cracking or peeling due to long-term use of the rotating electric machine 1.

[0035] Returning to FIG. 6B , the mold 90 is formed by an inner mold 92, an outer mold 91, an annular bottom mold 93, and a lid 94 (described later in FIG. 9C ). The stator 10 is placed inside this mold 90. At this time, the second coil segment 40 is held a predetermined distance (floating) from the bottom mold 93. This is because the permanent fixing resin 71 is filled around the periphery, including the underside of the temporary fixing resin 71b. The cylindrical waterproofing member 50 and the inner mold 92 are in good contact with each other to prevent the poured resin 71 from entering between them. To prevent the poured resin 71 from penetrating the contact surface between the cylindrical waterproofing member 50 and the inner mold 92 and bonding the cylindrical waterproofing member 50 and the inner mold 92, a mold release agent may be applied in advance to the surface of the inner mold 92 that contacts the cylindrical waterproofing member 50. This allows the inner mold 92 to be easily removed from the stator 10 after the resin 71 is molded.

[0036] The flange portion 52 of the cylindrical waterproofing member 50 is positioned so as to contact the outer end of the lead-out side of the first stator core 11a. When resin, described below, is poured into the cylindrical waterproofing member 50 in this state, the flange portion 52 is embedded in the resin after molding. Furthermore, the lower end portion 51a of the cylindrical portion 51 of the cylindrical waterproofing member 50 (on the opposite side to the lead-out side) extends a predetermined length from the end of the second stator core 11b in a direction parallel to the rotation axis Ax. However, the length of the lower end portion 51a is set so that it does not reach the bottom mold 93. A stepped portion 92b having a smaller outer diameter is formed in the lower portion of the inner mold 92. By forming the stepped portion 92b in this manner, the resin is sufficiently filled on the inner periphery of the lower end portion 51a, thereby properly fixing the cylindrical waterproofing member 50 on the opposite side to the lead-out side.

[0037] 8A and 8B show the state after resin has been filled from the state shown in FIGS. 6A and 6B. The filled resin hardens to completely cover the temporary fixing resins 71a and 71b shown in FIG. 6B. By using the same resin material for the temporary fixing resins 71a and 71b and the permanent fixing resin 71, the resins 71a and 71b are integrally incorporated into the permanent fixing resin 71. A cylindrically molded cylindrical waterproof member 50 is provided on the inner circumferential surface of the divided stator core 11, and both ends of the cylindrical waterproof member 50 adjacent to the coil ends are completely embedded in the resin 71. The cross-sectional shapes in FIGS. 8A and 8B are the same in the circumferential direction, and the flange portion 52 and the lower end portion 51a are located within the resin 71 at all circumferential locations. Therefore, moisture is completely prevented from penetrating from the ends of the cylindrical waterproof member 50 into the inner portions of the coil ends and the periphery of the bobbin 65. In particular, at the dividing position of the stator core 11, the resin 71 is completely filled into the gap between the joining surfaces of the stator cores 11a and 11b and the outer circumferential surface of the cylindrical waterproofing member 50.

[0038] The gap between the inner opening of each slot 14a, 14b (see FIG. 3) and the cylindrical waterproofing member 50 is filled with resin 71, thereby filling the gap and providing a strong bond. The temporary fixing resins 71a, 71b and the permanent fixing resin 71 may be made of different materials. The filling resin 71 may be injected using a transfer mold that applies a predetermined pressure, for example, but may also be formed using other molding methods.

[0039] 9A to 9D are diagrams showing the manufacturing procedure (steps 1 to 4) for the stator 10 of the rotating electric machine 1 according to this embodiment. In FIG. 9A, the stator 10 is mainly composed of divided stator cores 11a and 11b and the stator coil 20 formed therein. As shown in FIG. 3, the stator cores 11a and 11b are joined near the center in the direction of the rotation axis Ax. As shown in FIG. 4, the coil end portions of the multiple first coil segments 30 and the lead pieces 21 to 26 are temporarily fixed with resin 71a. Similarly, the coil end portions of the multiple second coil segments 40 are temporarily fixed with resin 71b. After the temporary fixing of the first coil segments 30 and the lead pieces 21 to 26 (see FIG. 2) to the stator core 11a and the temporary fixing of the second coil segment 40 to the stator core 11b are completed, the stator cores 11a and 11b are joined so as to be aligned in the direction of the rotation axis Ax. This joining simultaneously fits the concave and convex portions formed on the ends of the multiple first coil segments 30 and lead pieces 21 to 26 into the multiple second coil segments 40, thereby forming the stator coil 20.

[0040] Next, as shown in Fig. 9B , cylindrical waterproofing member 50 is inserted into the inner circumferential side of stator core 11. Insertion direction 59 is from one side of stator core 11 as viewed in the direction of rotation axis Ax, and in the example of Fig. 9B , insertion is from the side where lead pieces 21 to 26 (see Fig. 4 ) of stator coil 20 are provided. However, the insertion direction of cylindrical waterproofing member 50 is arbitrary, and it may be inserted from the stator core 11b side, opposite to Fig. 9B , so that flange portion 52 is located on the bottom surface side.

[0041] After the cylindrical waterproofing member 50 is attached to the stator core 11 as shown in FIG. 9C , they are set inside a mold 90. The mold 90 includes an outer mold 91, an inner mold 92, and a bottom mold 93, which are secured together with a plurality of bolts 96. The upper sides of the outer mold 91 and the inner mold 92 of the mold 90 are then closed with a disk-shaped lid 94. A resin injection hole 95 is formed in the lid 94, and the lid 94, the outer mold 91, and the inner mold 92 are secured together with bolts 97. Resin is then poured in the direction of arrow 99 in FIG. 9D , thereby covering the cylindrical portion 51 and the lower end portion 51 a of the cylindrical waterproofing member 50 as well as the coil end portion with resin 71. The resin 71 is thoroughly filled inside the slots 14 (see FIG. 3 ) of the stator cores 11 a and 11 b, particularly into the gaps inside and outside the bobbin 65. Furthermore, the resin 71 also comes into contact with the outer circumferential surface of the cylindrical waterproofing member 50 , so that the cylindrical waterproofing member 50 is firmly fixed by the resin 71 .

[0042] It is preferable that resin not be filled between the cylindrical waterproofing member 50 and the inner mold 92 of the mold 90. This means that the inner circumferential surface of the cylindrical waterproofing member 50 is exposed and faces the rotor 5 across a gap. Since no component (here, resin 71) is interposed on the surface of the cylindrical waterproofing member 50, problems such as component peeling can be avoided, ensuring stable waterproofing and high reliability over the long term. Furthermore, compared to a conventionally proposed application method in which a coating agent is applied to the inner surface of the assembled stator and then heat-cured (two-step application), the method of this embodiment requires fewer manufacturing steps and ensures reliable waterproofing. Furthermore, during the manufacturing process of the rotating electrical machine 1, even if the rotor 5 comes into contact with the cylindrical waterproofing member 50 when inserting the rotor 5 into the split stator 10, the cylindrical waterproofing member 50, being a film in the broad sense, has superior mechanical properties compared to conventionally used coating layers. Therefore, damage or cracking of the coating agent, which is a problem with conventional coating layers, is less likely to occur, significantly improving product reliability.

[0043] As described above, in the molding process of the stator coil 20 according to this embodiment, the cylindrical waterproof member 50 is placed on the inner periphery of the stator cores 11 a, 11 b before molding, via the inner mold 92, so as to fit along the inner periphery of the stator cores 11 a, 11 b. Thereafter, the outer mold 91 is attached, and the stators 11 a, 11 b and the cylindrical waterproof member 50 are integrated in one step. The shape of the cylindrical waterproof member 50 used in the rotating electric machine 1 is not limited to the shapes shown in FIGS. 7A and 7B . In particular, the cylindrical waterproof member 50 may have other shapes as long as it is a seamless, preformed, cylindrical, one-piece molded product in which both end portions of the cylindrical portion can be continuously embedded in the resin 71.

[0044] 10A to 10D are diagrams illustrating a manufacturing procedure for a stator core 11A according to a second embodiment. In the second embodiment, the shape of the cylindrical waterproofing member 50A is different from that of the cylindrical waterproofing member 50 of the first embodiment. FIG. 10A shows the shape of the stator core 11A before the insertion of the cylindrical waterproofing member 50A, which is the same shape as the stator core 11 shown in FIG. 9A. In FIG. 10B, the cylindrical waterproofing member 50A is inserted in the direction of arrow 59. As can be seen in this partial cross-sectional view, the cylindrical waterproofing member 50A has an expanded portion 53 formed on the upper side of the cylindrical portion 51, which expands slightly outward. Furthermore, the lower end portion 51a of the cylindrical portion 51 on the opposite side to the outlet extends a predetermined length from the end of the second stator core 11b in a direction parallel to the rotation axis Ax.

[0045] Next, as shown in Fig. 10C, the stator core 11A is inserted into a mold 90. The mold 90 is the same as that used in Fig. 9C, and liquid resin 71 is injected under pressure from a resin injection hole 95 in a lid portion 94 in the direction of an arrow 99 using the same method, and then cured.

[0046] 10D is a diagram showing a state in which the internal space of the mold 90 has been filled with resin without any gaps. As shown in FIG. 10D, the expanded tube portion 53 is fixed so as to be embedded within the resin 71 for final fixation. The lower end portion 51a of the cylindrical waterproofing member 50A is also fixed so as to be embedded within the resin 71 for final fixation. As a result, the entire inner circumferential surface of the stator core 11 is covered with the cylindrical waterproofing member 50A, which has high waterproofing properties, and therefore, it is possible to ideally prevent moisture from entering the periphery of the bobbin 65 from both end faces and the inner circumferential surface side of the stator core 11.

[0047] The rotating electric machines 1 of Examples 1 and 2 can be used to drive various devices. FIG. 11 shows one example, a screw-type air compressor 100 driven by the rotating electric machine 1. The air compressor 100 includes the rotating electric machine 1 that supplies rotational power and an air end 101 that generates compressed air using the rotational force of the rotating electric machine 1. The rotating electric machine 1 is a so-called interior permanent magnet synchronous motor, and includes a rotor 5 and a stator 10 housed within a housing 2. The rotating electric machine 1 has the structure described in this embodiment, but FIG. 11 omits the cylindrical waterproof member 50 and the resin 71 after full fixing. The housing 2 includes a cylindrical body 2a having openings on the front and rear sides, a front end bracket 2b attached to the front opening of the body 2a, and a rear end bracket 2c attached to the rear opening of the body 2a. A through hole is formed in the front end bracket 2b, and one end of the shaft 4, to which the rotor 5 is fixed, protrudes from the interior of the housing 2 toward the front side. The stator 10 is formed to include a stator core 11 and a stator coil 20 wound around the stator core 11. Fig. 11 shows a schematic view of the shape of the end core portion of the stator coil 20, and the detailed shape thereof is the shape described in Figs.

[0048] The M rotor 120 of the air end 101 is connected to the shaft 4 of the rotating electric machine 1 by a connecting means (e.g., a spline, a coupling, a gear, etc.) and supplies rotational power from the rotating electric machine 1 to the first shaft 105 of the air end 101. In this example, the shaft 4 and the first shaft 105 are directly connected, and their rotation axis is Ax. A first bevel gear 110 is provided at the tip of the first shaft 105, and the first bevel gear 110 is meshed with an adjacent second bevel gear 130, causing the second bevel gear 130 to rotate at a uniform speed in the opposite direction to the first bevel gear 110. Because the second bevel gear 130 is provided at the tip of the second shaft 135, the rotation of the second bevel gear 130 causes the F rotor 140 fixed to the second shaft 135 to rotate at a uniform speed in the opposite direction to the M rotor 120 fixed to the first shaft 105.

[0049] As the rotating electric machine 1 rotates, the M rotor 120 and the F rotor 140 rotate, and air is sucked in through the suction port of the M rotor 120 (not shown in the figure). As the M rotor 120 and the F rotor 140 further rotate, the teeth of each rotor disengage, and air is sucked into the tooth space. When the M rotor 120 and the F rotor 140 further rotate and the air is blocked by the wall of the casing 102, the suction is completed. The air trapped between the tooth space and the casing is compressed by the meshing of the rotors 120 and 140. As the rotors 120 and 140 rotate, the air moves axially and is further compressed between the tooth space 145 and the casing 102, reaching a discharge port (not shown in the figure) and reaching a predetermined pressure. The compressed air is discharged from the discharge port on the discharge side opened in the casing 102.

[0050] As described above, the rotating electric machine 1, 1A of the present invention is provided with a seamless cylindrical waterproof member sheet on the inner peripheral surface of the stator core, with both ends of the coil end embedded in molding resin and the inner periphery of the stator bonded with molding resin. This prevents moisture from entering the stator, improving the insulation reliability of the rotating electric machine. Furthermore, the present invention makes it possible to integrate the split stator core 11 and the cylindrical waterproof member 50, 50A in a single step.

[0051] REFERENCE SIGNS LIST 1... rotating electric machine, 2... housing, 4... shaft, 5... rotor, 10... stator, 11, 11A... stator core, 11a... first stator core, 11b... second stator core, 12a... core back core, 13a... teeth core, 14a, 14b... slot, 15... bobbin, 19... mold cover, 20... stator coil, 21 to 26... pull-out piece, 30... first coil segment, 31, 32... straight portion (first rectangular wire), 33, 34... inclined portion, 35, 36... end (convex portion), 36a... tip surface, 40... second coil segment, 41, 42... straight portion (second rectangular wire), 43, 44... inclined portion, 45, 46... end (concave portion), 4 6b...groove portion, 50, 50A...cylindrical waterproof member, 51...cylindrical portion, 51a...lower end portion, 52...flange portion, 53...expanded portion, 65...bobbin, 66a to 66d...insertion holes, 67, 68...jaw portion, 71...resin (for permanent fixation), 71a, 71b...resin (for temporary fixation), 90...mold, 91...outer mold, 92...inner mold, 92b...step portion, 93...bottom mold, 94...lid portion, 95...resin injection hole, 96, 97...bolt, 100...air compressor, 101...air end, 102...casing, 105...first shaft, 110...first bevel gear, 120...M rotor, 130...second bevel gear, 135...second shaft, 140...F rotor, 145...tooth space

Claims

1. A rotating electric machine comprising: a rotor fixed to a rotating shaft; and a stator core arranged on the outer periphery of the rotor, having a plurality of slots and formed by dividing it in the direction of the rotating shaft; stator coils arranged in the slots and wired so that a portion of the stator coil is exposed to the outside from an end of the stator core; and the exposed portion of the stator coil is molded with resin; and the rotating electric machine is characterized in that an integrally molded cylindrical waterproof member having insulating and waterproof properties is provided to cover the inner periphery of the stator core, and both one end and the other end of the cylindrical waterproof member in the direction of the rotating shaft are fixed with the resin.

2. A rotating electric machine as claimed in claim 1, wherein the stator core is divided into two parts, a first stator core and a second stator core, in the direction of the rotation axis, and the axial length of the cylindrical waterproofing member is greater than the total axial length of the divided stator cores.

3. A rotating electric machine as claimed in claim 2, wherein the cylindrical waterproofing member is formed with a cylindrical portion and a flange portion extending radially from one end of the cylindrical portion, the flange portion being molded so as to be embedded in the resin, and the other end of the cylindrical portion being molded so as to be embedded in the resin.

4. A rotating electric machine as described in claim 3, wherein the stator coil is formed by connecting, inside the slots, a plurality of hairpin-shaped first coil segments inserted into the slots from one side of the stator core in the direction of the rotation axis and a plurality of hairpin-shaped second coil segments inserted into the slots from the other side of the direction of the rotation axis, and the cylindrical waterproof member is positioned on the inner side of the first coil segments and the second coil segments, and is arranged so as to follow the inner surfaces of the teeth of the stator core.

5. A rotating electric machine as described in claim 4, wherein the cylindrical waterproof member has a portion of its outer surface bonded to the resin at the connection portion of the stator core, which is formed in two parts, so as to be continuous in the circumferential direction.

6. A rotating electric machine as described in claim 5, wherein a first bobbin made of resin is arranged in the slot of the first stator core to accommodate a plurality of the first coil segments arranged radially, and a second bobbin made of resin is arranged in the slot of the second stator core to accommodate a plurality of the second coil segments arranged radially, and the resin is filled between the inner surface of the first bobbin and the outer surface of the cylindrical waterproofing member, and between the inner surface of the second bobbin and the outer surface of the cylindrical waterproofing member.

7. A rotating electric machine according to claim 6, wherein the cylindrical waterproof member is integrally formed by injection molding of polyethylene terephthalate material with a heat resistance temperature of 120°C or higher, and the thickness of the cylindrical portion is less than half the size of the gap between the stator core and the rotor.

8. A rotating electric machine comprising: a stator core having a large number of slots opening to its inner periphery; a stator having stator coils wound in the slots; and a rotor fixed to a rotating shaft and rotating on the inner periphery of the stator core, wherein the stator coils are fixed to the stator coils by molding with resin; wherein a cylindrical waterproof member made of synthetic resin that is impermeable to non-magnetic bodies and has a shape that conforms to the inner periphery edge of the stator core is provided on the inner periphery of the stator core; and the cylindrical waterproof member is fixed to the stator core together with the stator coils by the resin.

9. A rotating electric machine as claimed in claim 8, wherein the cylindrical waterproof member is integrally formed by injection molding of polyethylene terephthalate material with a heat resistance temperature of 120°C or higher, and the outer edges of the openings on both sides of the cylindrical waterproof member are molded so as to be embedded in the resin.

10. A rotating electric machine as described in claim 9, characterized in that the resin is filled even into the gaps within the slots of the stator core, and the resin filled into the gaps within the slots comes into contact with the outer surface of the cylindrical waterproofing member, thereby firmly fixing the cylindrical waterproofing member to the stator core.

11. A method for manufacturing a rotating electric machine comprising: a rotor fixed to a rotating shaft; a stator core having a plurality of slots and arranged on the outer periphery of the rotor with a gap therebetween; and a stator coil formed by winding around the slots at predetermined intervals, the stator coil being connected so as to be exposed outward from the end of the stator core in the direction of the rotating shaft, and the exposed portion of the stator coil being molded with resin, wherein an integrated cylindrical waterproof member that covers the inner periphery of the stator core and has insulating and waterproof properties is inserted inside the stator core, and the resin is molded so that the cylindrical waterproof member is embedded in the resin on one and other sides in the direction of the rotating shaft, and the outer surface of the rotor and the inner surface of the cylindrical waterproof member face each other with a predetermined gap between them.

12. A method for manufacturing a rotating electric machine according to claim 11, wherein the resin molding step includes a temporary fixing step of temporarily fixing the exposed portions of the plurality of coil segments that make up the windings of the stator coil, and a final fixing step of fixing one side and the other side of the cylindrical waterproof member in the direction of the rotation axis by further forming resin on the portion that has been subjected to the temporary fixing step, wherein the cylindrical waterproof member is molded with the resin in the final fixing step.

13. A method for manufacturing a rotating electric machine as described in claim 12, wherein the stator core is formed by dividing it into two parts in the direction of the rotation axis, the stator coil is formed by connecting a plurality of hairpin-shaped first coil segments inserted into the slots from one side of the stator core in the direction of the rotation axis and a plurality of hairpin-shaped second coil segments inserted into the slots from the other side of the direction of the rotation axis within the slots, and the cylindrical waterproof member is manufactured to be longer than the total length of the divided stator core in the direction of the rotation axis.

14. A method for manufacturing a rotating electric machine as described in claim 13, characterized in that in the main fixing process using the resin, the resin is bonded to the outer surface of the cylindrical waterproofing member in addition to near both end portions in the direction of the rotation axis of the cylindrical waterproofing member.

15. A method for manufacturing a rotating electric machine as described in claim 14, wherein the cylindrical waterproof member is integrally formed by injection molding of polyethylene terephthalate material with a heat resistance temperature of 120 degrees or higher, a flange portion extending radially is formed on one end side of the cylindrical waterproof member in the direction of the rotation axis, and the flange portion is positioned so as to abut against one end face of the stator core, the end of the cylindrical waterproof member away from the flange portion is positioned so as to protrude from the other end face of the stator core, and the flange portion and the protruding portion are molded with the resin.

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