Rotor for electric pump

Abstract

To provide a rotor for an electric pump capable of improving productivity in resin molding.SOLUTION: A permanent magnet, a cylindrical rotor core that holds the permanent magnet, an adjacent member provided adjacent to the permanent magnet and the rotor core on one side in an axial direction, and a resin molded portion in which a drive portion that covers the permanent magnet, the rotor core, and the adjacent member and a blade portion that pumps a working fluid are integrally formed by resin molding, the adjacent member includes a closed surface portion including a portion that closes the other side in the axial direction of a whole-circumference hole portion formed in an end portion of the drive portion on the one side in the axial direction over the entire circumference in the circumferential direction, an inner extension portion that is continuous with the closed portion and extends inward in the radial direction, and an outer extension portion that is continuous with the closed portion and extends outward in the radial direction, and a first entire-circumferential projection portion welded to the resin molded portion.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a rotor for an electric pump. [Background technology]

[0002] Conventionally, a technique for preventing the working fluid from penetrating into the drive section of an electric pump rotor has been known, in which a drive section that covers a permanent magnet and a rotor core and a blade section that pumps a working fluid are formed by resin molding. For example, Patent Document 1 discloses a technique in which a drive section 3a of a rotor 3 is provided with a primary molded section 10 formed by resin molding and a secondary molded section 20 that is joined to the primary molded section 10 and is formed by resin molding using the same material as the primary molded section 10, so as to cover the permanent magnet 3c and the core 3d. An annular protrusion 12-15 that protrudes toward the secondary molded section 20 is provided at a joint 10a between the primary molded section 10 and the secondary molded section 20 (paragraphs 0018, 0019, Figures 2 and 3). The heat and pressure associated with resin molding the secondary molded section melt the vicinity of the tip of the annular protrusion of the primary molded section 10, and when the resin solidifies, the primary molded section and the secondary molded section are welded together. This seals the joint between the primary molded part and the secondary molded part, preventing the working fluid from entering the inside of the drive part 3a (paragraph 0019). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-8187 Summary of the Invention [Problem to be solved by the invention]

[0004] In conventional technology, it was necessary to mold the secondary molded portion after molding the primary molded portion, which required resin molding to be carried out in two separate steps, which was an obstacle to improving productivity.

[0005] The present invention has been made in view of the above-mentioned problems, and has an object to provide a rotor for an electric pump that can improve productivity in resin molding. [Means for solving the problem]

[0006] In one embodiment, the rotor for an electric pump comprises a permanent magnet, a cylindrical rotor core that holds the permanent magnet, an adjacent member arranged adjacent to the permanent magnet and one axial side of the rotor core, and a resin molded portion in which a drive unit that covers the permanent magnet, the rotor core, and the adjacent member and a blade portion that pumps the working fluid are integrally formed by resin molding, and the adjacent member has a closed surface portion that includes a portion that closes the other axial side of a full-circumferential hole formed around the entire circumference at the end of the one axial side of the drive unit, an inner extending portion that extends radially inward from the closed portion, and an outer extending portion that extends radially outward from the closed portion, and a first full-circumferential protrusion portion that is formed around the entire circumference toward the one axial side on the inner extending portion and the outer extending portion, respectively, and is welded to the resin molded portion.

[0007] The rotor core is a cylindrical member. Therefore, in order to integrally mold multiple members including the rotor core and cover the radially inner and outer sides of the rotor core with resin, it is necessary to configure the rotor core so that the radially inner and outer sides are not supported by a mold. As an example, it is possible to support one axial end of the rotor core with a mold and pour resin from the other axial end. In this case, since the rotor core is supported by the mold only at one axial end, in order to stably support it, it is possible to support the rotor core around the entire circumferential direction, for example, at one axial end.

[0008] However, when resin is molded using such a mold, the area where the rotor core was supported becomes a full-circumferential hole extending around the entire circumference. In this case, the working fluid can seep into the gap between the resin and the rotor core through the full-circumferential hole. If the working fluid seeps into the gap between the resin and the rotor core, it can cause corrosion of the rotor core or permanent magnets, making the product unsuitable.

[0009] Therefore, in the rotor for an electric pump, the rotor core, permanent magnets, and adjacent components are integrated within a mold, and the adjacent components are supported by the mold. In this case, one axial end of the adjacent component closes the other axial end of the full-circumferential hole. However, working fluid may enter the drive unit through the full-circumferential hole and through gaps between the inner and outer extensions and the resin-molded component. Therefore, a first full-circumferential protrusion is provided on each of the inner and outer extensions to prevent the working fluid from entering the drive unit. This configuration eliminates a problem that can arise with integral molding, namely, the problem of working fluid entering the drive unit through the support portion of the mold during resin molding, making it possible to provide an integrally molded rotor. As a result, productivity in resin molding can be improved. [Brief explanation of the drawings]

[0010] [Figure 1] 1A and 1B are perspective views of a rotor for an electric pump. [Figure 2] 2 is a perspective cross-sectional view of the rotor for the electric pump taken along line AA'. FIG. [Figure 3] FIG. 2 is a perspective view of a permanent magnet module. [Figure 4] FIG. 4A is a view of the permanent magnet module as seen from one axial side, and FIG. 4B is a view of the permanent magnet module as seen from the other axial side. [Figure 5] FIG. 10 is a cross-sectional view of the permanent magnet module taken along line BB'. [Figure 6] 6A and 6B are perspective views of adjacent members. [Figure 7] 1 is a flowchart showing a method for manufacturing a rotor for an electric pump. DETAILED DESCRIPTION OF THE INVENTION

[0011] Here, the embodiments of the present invention will be described in the following order. (1) Overall configuration of the electric pump: (2) Rotor details: (3) Rotor manufacturing method: (4) Other embodiments:

[0012] (1) Overall configuration of the electric pump: Fig. 1A is a perspective view of the electric pump rotor according to this embodiment, as seen from one axial side, and Fig. 1B is a perspective view of the electric pump rotor according to this embodiment, as seen from the other axial side. Fig. 2 is a perspective cross-sectional view of the electric pump rotor according to this embodiment, taken along line A-A'. The electric pump according to this embodiment is, for example, an electric water pump that pumps a working fluid, such as coolant (LLC), for cooling an automobile engine or the like, to a part of the automobile to be cooled.

[0013] In this specification, the direction parallel to the rotation axis Ax is referred to as the axial direction. The direction along the circumference of a circle centered on the rotation axis Ax is referred to as the circumferential direction, and the direction parallel to the radius of the circle is referred to as the radial direction. Furthermore, in this specification, the direction toward the rotation axis Ax in the radial direction as viewed from a certain component is referred to as the radially inner direction, and the direction opposite the rotation axis Ax is referred to as the radially outer direction.

[0014] The electric pump includes a cylindrical stator (not shown) that generates a magnetic field, a rotor 100 (electric pump rotor) disposed radially inside the stator, a shaft (not shown) that axially penetrates the rotor 100, and a housing (not shown) that accommodates the stator, rotor 100, and shaft and rotatably supports both ends of the shaft. The magnetic field generated by the stator causes the rotor 100 to rotate integrally with a portion including the blades 42, centered on the shaft. The electric pump is a device that, by the rotation of the blades 42, draws working fluid present on the IN side into the blades 42 and discharges it to the OUT side.

[0015] (2) Detailed rotor configuration FIG. 3 is a perspective view of a permanent magnet module according to this embodiment. FIG. 4A is a view of the permanent magnet module according to this embodiment as seen from one axial side, and FIG. 4B is a view of the permanent magnet module according to this embodiment as seen from the other axial side. FIG. 5 is a cross-sectional view of the permanent magnet module according to this embodiment along line B-B'. Note that in FIG. 5, hatching of rotor core 20 has been omitted for ease of viewing. FIG. 6A is a perspective view of the adjacent member according to this embodiment as seen from the other axial side, and FIG. 6B is a perspective view of the adjacent member according to this embodiment as seen from one axial side.

[0016] 1B and 2, the rotor 100 includes a permanent magnet 10, a rotor core 20, an adjacent member 30, and a resin molded portion 40. The permanent magnet 10, the rotor core 20, and the adjacent member 30 together form a permanent magnet module M1.

[0017] The permanent magnet 10 is made of a hard magnetic material and, when magnetized, retains its magnetic force for a long period of time. The permanent magnet 10 is a substantially rectangular parallelepiped whose axial length is longer than its circumferential length, and the cross-sectional shape perpendicular to the axial direction is the same throughout the entire axial length. As shown in FIG. 4A , the permanent magnet 10 has a portion 11 formed to be thin in the radial direction at both circumferential ends, and a portion 12 formed to be relatively thick in the radial direction and longer in the circumferential direction than the thin portion 11. The radially inner end faces of the thin portion 11 and the thick portion 12 are formed flat, and the radially outer end face of the thick portion 12 is formed in an arc shape along the outer diameter portion 20b of the rotor core 20.

[0018] As shown in FIGS. 3 and 4A, the rotor core 20 is formed in a cylindrical shape and holds permanent magnets. The rotor core 20 is formed from a material in which electromagnetic steel sheets, such as silicon steel sheets, which are soft magnetic materials, are laminated. Electromagnetic steel sheets generally have high magnetic permeability, and eddy current loss can be reduced by laminating these sheets together. The rotor core 20 has an arrangement portion 21 and a protruding portion 22. The arrangement portion 21 is arranged in a circumferential direction on an outer diameter portion 20b that forms the radially outer surface of the cylindrical rotor core 20, and is a portion in which a plurality of permanent magnets 10 are arranged. For example, six arrangement portions 21 are arranged in a circumferential direction on the outer diameter portion 20b at equal intervals (60-degree intervals), and six permanent magnets 10 are arranged in each of the arrangement portions 21. The arrangement portion 21 has openings that allow the permanent magnets 10 to be inserted and removed in the axial direction from one axial end and the other axial end of the rotor core 20 when the rotor core 20 is in a standalone state. The mounting portion 21 is a recess recessed from the outer diameter portion 20b of the rotor core 20, and the radially inner surface of the recess is formed as a flat surface. A predetermined clearance is provided between the mounting portion 21 and the protruding portion 22 and the permanent magnet 10 so that the permanent magnet 10 can be inserted and removed in the axial direction. Although it has been stated that the rotor core 20 is formed in a cylindrical shape, the cylindrical shape here broadly includes a shape in which holes are formed radially inside the electromagnetic steel sheets that make up the rotor core 20, and the electromagnetic steel sheets are stacked in the axial direction, with the same shape continuing in the axial direction, and the inner diameter portion 20a and the outer diameter portion 20b do not need to be strictly annular in the direction perpendicular to the axial direction.

[0019] The protruding portions 22 are circumferentially protruding portions that face each other radially outward of the permanent magnets 10 at both circumferential ends of each of the multiple mounting portions 21. Facing each other means that a pair of protruding portions 22 at both circumferential ends of each of the multiple mounting portions 21 face each other. The protruding portions 22 are portions that hold the thinly formed portions 11 of the permanent magnets 10 at both circumferential ends of each of the multiple mounting portions 21. In other words, the protruding portions 22 are provided at both circumferential ends of each of the multiple mounting portions 21, and can be said to have overlapping portions that at least partially overlap with the permanent magnets 10 when viewed from the radial direction. The protruding portions 22 are portions of the outer diameter portion 20b of the rotor core 20 that protrude circumferentially at both circumferential ends of each of the multiple mounting portions 21, radially outward of the permanent magnets 10. A gap is formed between the protruding portions 22 and the radially inner surface of the mounting portion 21. The thinly formed portions 11 of the permanent magnets 10 are inserted into the gap. The protruding portion 22 can prevent the permanent magnets 10 from falling off in the radial direction in the state of the permanent magnet module M1.

[0020] The adjacent member 30 is provided adjacent to one axial side of the permanent magnet 10 and the rotor core 20. The adjacent member 30 is formed of resin, and has a closed surface portion 31, a first circumferential protrusion 32, a positioning portion 33, a second circumferential protrusion 34, a press-fit protrusion 35, and an overlapping portion 36, as shown in Figures 6A and 6B.

[0021] The closed surface portion 31 is formed in the shape of an annular flat plate having a constant thickness in the axial direction and a predetermined width in the radial direction. The closed surface portion 31 includes a portion 31a, an inner extending portion 31b, and an outer extending portion 31c. The portion 31a, the inner extending portion 31b, and the outer extending portion 31c are portions that exist around the entire circumferential direction of the closed surface portion 31, and exist in the order of 31b, 31a, and 31c from the radially inner side. The portion 31a is a portion that closes the other axial side of the entire circumferential hole portion H1 formed around the entire circumferential direction in the end portion 41a on one axial side of the drive portion 41. The inner extending portion 31b extends radially inward continuously from the portion 31a. The outer extending portion 31c extends radially outward continuously from the portion 31a.

[0022] The first circumferential protrusions 32 are formed on the inner extending portion 31b and the outer extending portion 31c, respectively, around the entire circumferential direction toward one axial side, and are welded to the resin molded portion 40. At least two first circumferential protrusions 32 are formed on each of the inner extending portion 31b and the outer extending portion 31c. That is, the first circumferential protrusions 32 include a small-diameter inner protrusion 32a formed on the inner extending portion 31b, a large-diameter inner protrusion 32b with a larger diameter than the small-diameter inner protrusion 32a formed on the inner extending portion 31b, a small-diameter outer protrusion 32c formed on the outer extending portion 31c, and a large-diameter outer protrusion 32d with a larger diameter than the small-diameter outer protrusion 32c formed on the outer extending portion 31c. In this embodiment, the first circumferential protrusions 32, 32a to 32d, extend toward one axial side, are formed without interruption around the entire circumference, and have a constant axial length and a constant radial thickness. The first circumferential protrusions 32 melt near their tips due to the heat and pressure associated with resin molding of the resin molded portion 40, and are welded to the resin molded portion 40 when the resin hardens, thereby sealing the joints between the inner extending portion 31b and the outer extending portion 31c and the resin molded portion 40. This prevents the working fluid from entering the inside of the drive portion 41 through the circumferential hole H1.

[0023] 2 and 5, the reason why two first circumferential protrusions 32 are formed on each of the inner extending portion 31b and the outer extending portion 31c will be explained. In this embodiment, the rotor core 20 is made of metal, and the resin-molded portion 40 is made of resin, resulting in a difference in linear expansion coefficient. The end portion 41a on one axial side of the drive portion 41 is provided with the circumferential hole H1. Therefore, particularly at low temperatures (e.g., −40°C), thermal stress occurs in a direction in which the resin contracts and opens from the circumferential hole H1, i.e., the radially inner and outer portions of the circumferential hole H1 at the end portion 41a on one axial side of the drive portion 41 are pulled radially inward and radially outward from the circumferential hole H1. Therefore, if one first circumferential protrusion 32 is formed on each of the inner extending portion 31b and the outer extending portion 31c, thermal stress is concentrated on the protrusions, and therefore the allowable thermal stress of the protrusions must be set high. In this embodiment, two first circumferential protrusions 32 are formed on each of the inner extending portion 31b and the outer extending portion 31c. This allows thermal stress to be distributed to the two first circumferential protrusions 32, making it possible to set a relatively low allowable thermal stress for each first circumferential protrusion 32. Even if the small-diameter inner protrusion 32a and the large-diameter outer protrusion 32d, which experience greater thermal stress at low temperatures, are destroyed, the large-diameter inner protrusion 32b and the small-diameter outer protrusion 32c can maintain a welded state and maintain sealing performance. This allows for a fail-safe function.

[0024] A plurality of positioning portions 33 are formed spaced apart in the circumferential direction and are used to radially position the adjacent member 30 relative to the mold that molds the resin molded portion 40. For example, three positioning portions 33 are provided side by side at equal intervals (120 degrees apart) in the circumferential direction on the inner diameter portion 31d that forms the radially inner surface of the closed surface portion 31. As shown in FIG. 4B , the inner diameter portion 31d of the closed surface portion 31 is formed in a substantially hexagonal shape when viewed from the axial direction. The outer diameter portion 31e of the closed surface portion 31 is formed in a substantially annular shape when viewed from the axial direction. The positioning portions 33 are formed on the linear portions of the substantially hexagonal shape on the inner diameter portion 31d of the closed surface portion 31. The positioning portions 33 are formed to protrude radially inward from the inner diameter portion 31d of the closed surface portion 31. The positioning portion 33 extends a predetermined distance from the inner diameter portion 31d of the closed surface portion 31 toward the other axial side, and the inner diameter side of the extended portion has a positioning surface that is a flat surface that abuts against the mold. The positioning portion 33 does not need to be press-fitted into the inner diameter portion 20a of the rotor core 20, and a predetermined clearance may be provided between the outer diameter side of the extended portion and the inner diameter portion 20a of the rotor core 20.

[0025] The second circumferential protrusion 34 is formed around the entire outer periphery of each of the positioning portions 33 (positioning surfaces) in a plane perpendicular to the radial direction, and is welded to the molded resin portion 40. The second circumferential protrusion 34 is formed to be thinner in the radial direction than the positioning portion 33 at the center of the radial thickness of the positioning portion 33, and is covered by the molded resin portion 40. In this embodiment, the second circumferential protrusion 34 extends radially straight from the outer periphery of the positioning portion 33 in a plane perpendicular to the radial direction, and is formed with a constant length and thickness without interruption around the entire outer periphery of the positioning portion 33. The vicinity of the tip of the second circumferential protrusion 34 melts due to the heat and pressure associated with resin molding of the molded resin portion 40, and is welded to the molded resin portion 40 when the resin hardens, thereby sealing the joint between the positioning portion 33 of the adjacent member 30 and the molded resin portion 40. This makes it possible to prevent the working fluid from entering the inside of the drive part 41 through the gap between the positioning part 33 and the resin molded part 40 .

[0026] The press-fit protrusions 35 are formed in a plurality at intervals in the circumferential direction and press-fit into the inner diameter portion 20a that forms the radially inner surface of the cylindrical rotor core 20. For example, three press-fit protrusions 35 are provided in a row at equal intervals (120° intervals) in the circumferential direction on the inner diameter portion 31d of the closed surface portion 31. The press-fit protrusions 35 are formed on each linear portion of the substantially hexagonal cross section of the inner diameter portion 31d of the closed surface portion 31. The positioning portions 33 and the press-fit protrusions 35 are arranged alternately in the circumferential direction. As shown in FIG. 6A , the press-fit protrusions 35 have a flat portion 35a and a crushed portion 35b. The flat portion 35a is a flat portion extending a predetermined distance from the closed surface portion 31 toward the other axial side. The radial direction is the thickness direction of the closed surface portion 31, and the direction perpendicular to the radial direction is parallel to the flat surface of the closed surface portion 31. The crushed portion 35b is provided adjacent to the radially outer side of the flat plate portion 35a, extends in the axial direction, and bulges radially outward in a semi-round rod shape to be crushed when press-fitted into the inner diameter portion 20a of the rotor core 20. By configuring the press-fit protrusion 35 to be press-fitted into the inner diameter portion 20a of the rotor core 20, the rotor core 20 and the adjacent member 30 can be easily joined. Furthermore, by joining the rotor core 20 and the adjacent member 30, it is possible to prevent the rotor core 20 and the adjacent member 30 from falling off when the permanent magnet module M1 is transported, etc.

[0027] As shown in FIGS. 3 and 6A, the overlapping portion 36 is provided on one axial side of the permanent magnet 10 and at least partially overlaps with the permanent magnet 10 when viewed from the axial direction. The overlapping portion 36 can also be considered a protruding portion that protrudes radially from one axial side of each of the multiple permanent magnets 10 arranged in each of the multiple arrangement portions 21. A plurality of overlapping portions 36 are arranged at equal intervals (120-degree intervals) in the circumferential direction corresponding to the multiple permanent magnets 10. In this embodiment, each overlapping portion 36 has a portion that overlaps with the entire permanent magnet 10 when viewed from the axial direction. Note that FIG. 6A shows only one of the multiple overlapping portions 36. The presence of the overlapping portion 36 makes it possible to prevent the permanent magnets 10 from falling off in the axial direction when the permanent magnet module M1 is in its assembled state.

[0028] The resin molded portion 40 is formed integrally by resin molding, with a drive portion 41 that covers the permanent magnets 10, the rotor core 20, and the adjacent member 30, and a blade portion 42 that pumps the working fluid.

[0029] As shown in FIGS. 1A, 1B, and 2, the drive section 41 of the resin molded section 40 covers the permanent magnet module M1, including the permanent magnets 10, the rotor core 20, and the adjacent member 30, from the outside (in all directions, including the radially inner side, the radially outer side, one axial side, and the other axial side). Only the closed portion 31a of the closed surface section 31 of the adjacent member 30 and the positioning surface of the positioning section 33 are exposed from the drive section 41. The blade section 42 of the resin molded section 40 is also referred to as an impeller section. The blade section 42 has an eave section 42a and multiple blades 42b. The eave section 42a is provided on the other axial side of the drive section 41 via a connection section 43 having a smaller diameter than the drive section 41, and is formed with a larger diameter than the drive section 41 and the connection section 43. The multiple blades 42b extend spirally on the other axial side of the eave section 42a. The blades 42b are formed so that their axial lengths become shorter as they extend radially outward. The resin molded portion 40 is formed such that the drive portion 41 and blade portions 42 of the resin molded portion 40 are integrally formed of resin in a state in which the permanent magnet module M1 and the bearing 50, into which the shaft (not shown) of the rotor 100 is inserted, are placed as insert parts in a mold. As shown in FIG. 2, the bearing 50 is formed in a cylindrical shape, and the central axis of the cylinder coincides with the rotation axis Ax. The bearing 50 is disposed radially inside the resin molded portion 40 and extends axially over substantially the entire axial area of ​​the resin molded portion 40. The bearing 50 is formed of, for example, sintered carbon, but metal, resin, etc. may also be used.

[0030] (3) Rotor manufacturing method: 7 is a flowchart showing a method for manufacturing a rotor for an electric pump according to this embodiment. First, the permanent magnet 10, rotor core 20, and adjacent member 30 are each manufactured in advance. Then, in step S100, the press-fit protrusion 35 of the adjacent member 30 is press-fitted into the inner diameter portion 20a of the rotor core 20 (press-fitting process). Specifically, while crushing the crushed portion 35b of the press-fit protrusion 35, the adjacent member 30 is press-fitted into the inner diameter portion 20a of the rotor core 20 until the end face on one axial side of the rotor core 20 and the end face on the other axial side of the adjacent member 30 come into contact.

[0031] Next, in step S110, the permanent magnet 10 is slid from the opening on the other axial side of the mounting portion 21 of the rotor core 20 toward one axial side into the mounting portion 21 (insertion process). As the permanent magnet 10 is inserted, it comes into contact with the overlapping portion 36 of the adjacent member 30. In this state, the permanent magnet module M1 of the permanent magnet 10, rotor core 20, and adjacent member 30 is completed.

[0032] Next, in step S120, the permanent magnet module M1 and the bearing 50 are placed in a mold (placement process). The mold is provided with a full-circumferential convex portion, three upright portions, and a support portion. The full-circumferential convex portion is formed in a substantially hexagonal shape around the entire circumferential direction and supports the end portion 30a (portion 31a of the closed surface portion 31) on one axial side of the adjacent member 30. This positions the permanent magnet module M1 in the axial direction. The three upright portions extend toward the other axial side and are arranged at equal intervals (120-degree intervals) in the circumferential direction. The three upright portions extend a predetermined distance in the circumferential direction and have at least the circumferential length of the positioning portion 33 of the adjacent member 30. The three upright portions are located between the positioning portion 33 of the adjacent member 30 and the outer peripheral surface of the bearing 50. The upright portions abut against the positioning surface of the positioning portion 33 of the adjacent member 30. This positions the permanent magnet module M1 in the radial direction. The support portion is provided near the base of one axial side of the upright portion, and is a portion that supports the end portion 50a on one axial side of the bearing 50. The end portion 50a on one axial side of the bearing 50 is supported by the support portion to position the bearing 50 in the axial direction, and the outer peripheral surface of the bearing 50 is supported by the three upright portions to position the bearing 50 in the radial direction.

[0033] Then, in step S130, resin is poured into the mold from the other axial end of the mold to perform resin molding (resin molding process). By performing resin molding in a state where the end 30a on one axial side of the adjacent member 30 is supported by the entire circumferential protrusion of the mold, a full circumferential hole H1 is formed in the end 41a on one axial side of the drive unit 41. Details will be described later. By performing resin molding in a state where the positioning portions 33 of the adjacent member 30, the end 50a on one axial side of the bearing 50, and the outer peripheral surface of the bearing 50 are supported by the upright portions of the mold, hollow portions 101 extending in the axial direction are formed radially inward of the three positioning portions 33 lined up in the circumferential direction, and connecting portions 102 extending in the axial direction radially inward of the three press-fit protrusions 35 lined up in the circumferential direction, connecting the resin molded portion 40 and the bearing 50, are formed. Therefore, the positioning surface of the positioning portion 33 is exposed to the hollow portion 101 (outside the resin molded portion), and the press-fit protrusion 35 is contained within the connecting portion 102 (inside the resin molded portion). Therefore, the positioning portion 33 is provided with the second all-around protrusion 34, while the press-fit protrusion 35 is not provided with such an all-around protrusion.

[0034] Finally, in step S140, the rotor 100 is removed from the mold. The magnetizing device in the next process has at least one pin protruding from its base toward the other axial direction. The rotor 100 (rotational position of the permanent magnet 10) is positioned by rotating the rotor 100 in the circumferential direction and fitting at least one pin into multiple (e.g., three) holes H2 provided in the end 41a on one axial side of the drive unit 41. An object carrying a magnetic field, such as a coil, is then brought close to the permanent magnet 10 from the radial outside of the drive unit 41 to magnetize the north and south poles (magnetization process).

[0035] Here, the reason for providing some kind of hole in the end 41a on one axial side of the drive part 41 is (A) to support the permanent magnet module M1 including the permanent magnet 10, rotor core 20, and adjacent member 30 from one axial side of the adjacent member 30 during resin molding. The reason for providing hole H2 in the end 41a on one axial side of the drive part 41 is (B) to use it for positioning the rotor 100 (the rotational position of the permanent magnet 10) before magnetization. If this is the only reason, providing only hole H2 will be able to fulfill the functions of (A) and (B).

[0036] Furthermore, in addition to hole H2, the reason for providing full-circumferential hole H1 at end 41a on one axial side of drive portion 41 is that (c) if full-circumferential hole H1 is not provided, as shown in Fig. 2, resin flowing from the other axial side will split and flow toward inner diameter portion 20a (arrow D) and outer diameter portion 20b (arrow E) of rotor core 20, creating a position where the resin will join again, inevitably creating a weld line, and if this weld line coincides with a position where high stress occurs, the possibility of product defects increasing. Therefore, by providing full-circumferential hole H1 at end 41a on one axial side of drive portion 41, a dividing structure is achieved in which the resin that has split and flowed toward inner diameter portion 20a and outer diameter portion 20b of rotor core 20 will not join together. 1B and 2, which is an edge portion on one axial side of permanent magnet 10, product defects may occur if the joining position of the resin (weld line) coincides with part C, which is an edge portion on one axial side of permanent magnet 10. For the above reasons, a full-circumferential hole H1 is provided at end 41a on one axial side of drive part 41.

[0037] In this embodiment, the first all-around protrusions 32 are formed on the inner extending portion 31b and the outer extending portion 31c of the adjacent member 30 along the entire circumferential direction toward one axial side, respectively, and are welded to the resin molded portion 40, thereby preventing the working fluid from entering the drive portion 41 through the all-around hole H1. This solves a problem that can arise with integral molding, namely, the problem of the working fluid entering the drive portion 41 from the portion supported by the all-around protrusions of the mold during resin molding, making it possible to provide an integrally molded rotor 100. The ability to integrally mold the rotor 100 from resin allows for improved productivity and reduced costs in resin molding compared to when multiple resin moldings are performed.

[0038] (4) Other embodiments: The above embodiment is one example for carrying out the present invention, and various other embodiments are also possible. For example, the number of permanent magnets 10 and mounting portions 21 is not limited to six and may be other numbers. The shapes and sizes of the permanent magnets 10 and mounting portions 21 may also be various. The medium pumped by the blade portions 42 of the rotor 100 may be any working fluid and is not limited to cooling water, etc. Furthermore, the order of interchangeable steps in the rotor manufacturing method may be changed. For example, the order of S110 and S120 may be changed in the manufacturing method shown in FIG. 7.

[0039] "The hole H1 being formed around the entire circumference in the circumferential direction" includes cases where it is formed continuously in the circumferential direction and cases where it is formed discontinuously in the circumferential direction. "Discontinuous" means that the inner diameter side and the outer diameter side of the hole H1 are partially connected. If it is formed continuously in the circumferential direction, a divided structure can be achieved in which the resin that flows separately to the inner diameter portion 20a and the outer diameter portion 20b of the rotor core 20 does not merge. This eliminates the occurrence of weld lines and reliably prevents product defects caused by the weld lines overlapping with areas where high stress occurs. On the other hand, if the weld lines do not overlap with areas where high stress occurs and the occurrence of weld lines is acceptable, the hole H1 may be formed discontinuously in the circumferential direction.

[0040] The expression "driver 41 and blade 42 are integrally formed by resin molding" means that driver 41 and blade 42 are formed in a connected state by a single resin molding operation. This does not include cases where driver 41 and blade 42 are formed separately by resin molding and then joined together, or cases where one of them is formed by resin molding and then the other is resin molded with a portion overlapping, thereby forming the two into one unit.

[0041] The configuration in which the first all-around protrusion 32 is formed around the entire circumference includes a case in which it is formed without gaps in the circumferential direction. By forming it without gaps in the circumferential direction, it is possible to reliably prevent the working fluid from entering the inside of the drive unit 41 through gaps. Furthermore, the configuration in which the first all-around protrusion 32 is formed around the entire circumference also includes a case in which, when the all-around hole H1 is formed discontinuously in the circumferential direction, the first all-around protrusion 32 has a plurality of surrounding portions formed to surround the entire circumference of each of the plurality of holes or each of the entire circumference of a group of holes that make up the discontinuous all-around hole H1, and the plurality of surrounding portions are lined up in the circumferential direction. By forming the plurality of surrounding portions to surround the entire circumference of each of the plurality of holes or each of the entire circumference of a group of holes that make up the discontinuous all-around hole H1, it is possible to prevent the working fluid from entering the inside of the drive unit 41 through each of the discontinuous all-around hole H1.

[0042] Forming the second all-around protrusion 34 around the entire outer periphery of each of the positioning portions 33 means that the second all-around protrusion 34 is formed without any gaps around the entire outer periphery. By forming the second all-around protrusion 34 without any gaps around the entire outer periphery, it is possible to reliably prevent the working fluid from entering the inside of the drive portion 41 through gaps.

[0043] The closed portion 31a of the closing surface portion 31 is a portion that closes the other axial side of the circumferential hole portion H1 and is a portion that overlaps with the circumferential hole portion H1 when viewed from the axial direction. A reliable seal is not maintained by closing the circumferential hole portion H1 with the closing surface portion 31, but a reliable seal is maintained by the first circumferential protrusion portion 32.

[0044] The rotor core 20 and adjacent member 30 may have various shapes and sizes. For example, the inner diameter portion 20a of the rotor core 20 and the inner diameter portion 31d of the closed surface portion 31 of the adjacent member 30 are not limited to a substantially hexagonal shape and may have other shapes. Furthermore, although the bearing 50 is insert-molded, the bearing 50 is not an essential component.

[0045] The number of positioning portions 33 and press-fit protrusions 35 of the adjacent member 30 is not limited to three and may be other numbers. Furthermore, the shape and size of the positioning portions 33 and press-fit protrusions 35 may be various. If the adjacent member 30 can be positioned radially by other configurations, the positioning portions 33 are not essential. Furthermore, the press-fit protrusions 35 do not need to be press-fitted into the inner diameter portion 20a of the rotor core 20, but may be press-fitted into another portion, for example, the outer diameter portion 20b of the rotor core 20. Furthermore, even if the press-fit protrusions 35 are not provided, the press-fit protrusions 35 are not essential as long as the permanent magnet module M1 can be transported without disassembly when placed in a mold and is reliably positioned in the mold. If the press-fit protrusions 35 are not provided, in S100 of the manufacturing method shown in FIG. 7 , the rotor core 20 is simply placed on the other side of the adjacent member 30, rather than being press-fitted.

[0046] The protruding portion 22 of the rotor core 20 does not need to protrude over the entire axial area, but it is sufficient that at least a portion of the protruding portion prevents the permanent magnets 10 from falling off in the radial direction. The overlapping portion 36 of the adjacent member 30 does not need to overlap the entire area of ​​the permanent magnet 10 with the adjacent member 30 when viewed in the axial direction, but it is sufficient that at least a portion of the overlapping portion prevents the permanent magnets 10 from falling off in the axial direction.

[0047] The number of first circumferential protrusions 32 of the adjacent member 30 is not limited to two on the inner extending portion 31b and two on the outer extending portion 31c. Other numbers are possible as long as there is at least one on the inner extending portion 31b and at least one on the outer extending portion 31c. The shapes and sizes of the first circumferential protrusions 32 may also be various. For example, considering the flow of resin during resin molding and the degree of welding, the shapes of 32a to 32d shown in FIG. 5 may be tapered toward the tip. Furthermore, the axial lengths and radial thicknesses of 32a to 32d may be different. Specifically, the axial lengths of 32a and 32d, which are the innermost and outermost in the radial direction and which experience higher thermal stress at low temperatures, may be longer than those of 32b and 32c. The reverse may also be true.

[0048] Similarly, various shapes and sizes may be employed for the second circumferential protrusion 34. The second circumferential protrusion 34 may be tapered toward the tip in advance, taking into consideration the flow of resin during resin molding and the degree of welding. [Explanation of symbols]

[0049] 100... rotor (electric pump rotor), 10... permanent magnet, 20... rotor core, 20a... inner diameter portion, 20b... outer diameter portion, 21... arrangement portion, 22... protruding portion, 30... adjacent member, 31... closed surface portion, 31a... closed portion, 31b... inner extending portion, 31c... outer extending portion, 32... first all-around protrusion portion, 33... positioning portion, 34... second all-around protrusion portion, 35... press-fit protrusion portion, 36... overlapping portion, 40... resin molded portion, 41... drive portion, 41a... end portion, 42... blade portion, H1... all-around hole portion

Claims

1. A permanent magnet and a cylindrical rotor core that holds the permanent magnets; an adjacent member provided adjacent to the permanent magnet and one axial side of the rotor core; a resin molded portion in which a drive portion that covers the permanent magnet, the rotor core, and the adjacent members and a blade portion that pumps the working fluid are integrally formed by resin molding, The adjacent member is a closed surface portion including a portion that closes the other axial side of a full circumferential hole that is formed around the entire circumference in the circumferential direction at an end portion on one axial side of the drive portion, an inner extending portion that extends radially inwardly from the closed portion, and an outer extending portion that extends radially outwardly from the closed portion; a first full-circumferential protrusion formed on each of the inner extending portion and the outer extending portion toward one axial side over the entire circumference in the circumferential direction and welded to the resin molded portion;

2. The rotor for an electric pump according to claim 1 , wherein at least two of the first full-circumferential projections are formed on the inner extending portion and at least two of the first full-circumferential projections are formed on the outer extending portion.

3. The adjacent member is a plurality of positioning portions formed at intervals in a circumferential direction and used for radially positioning the adjacent member with respect to a mold that molds the resin molded portion; 3. The rotor for an electric pump according to claim 1, further comprising: a second full-circumferential protrusion formed around the entire outer periphery of each of the positioning portions in a plane perpendicular to the radial direction and welded to the resin molded portion.

4. The rotor core is a plurality of arrangement portions arranged side by side in the circumferential direction on an outer diameter portion that forms a radially outer surface of the cylindrical rotor core, the arrangement portions accommodating the plurality of permanent magnets; and protruding portions protruding in the circumferential direction at both circumferential ends of each of the plurality of arrangement portions and facing each other radially outward of each of the plurality of permanent magnets, The adjacent member is a plurality of press-fit protrusions formed at intervals in the circumferential direction and press-fitted into an inner diameter portion that forms a radially inner surface of the cylindrical rotor core; 3. The rotor for an electric pump according to claim 1, further comprising an overlapping portion provided on one axial side of the permanent magnet and at least partially overlapping with the permanent magnet when viewed from the axial direction.

Images