CN113037033A

CN113037033A - Resin molding method, jig, and resin molding apparatus

Info

Publication number: CN113037033A
Application number: CN202010278450.2A
Authority: CN
Inventors: 仲彻
Original assignee: Naka Liquid Control Co ltd
Current assignee: Naka Liquid Control Co ltd
Priority date: 2019-12-24
Filing date: 2020-04-10
Publication date: 2021-06-25
Anticipated expiration: 2040-04-10
Also published as: JP2021100361A; CN113037033B; JP6774075B1

Abstract

The invention provides a resin molding method for performing resin molding on a stator assembly with a core having a slot extending along a radial direction. In a method for resin molding a stator assembly 10 in which a coil 23 is wound around an annular core 11, the core 11 includes: a plurality of grooves (12), the grooves (12) having openings (12a, 12b) at an outer circumferential surface (20) and an inner circumferential surface (21) and extending in a radial direction, and a gap (17), the gap (17) communicating with the grooves (12) at a first face (18), the method comprising: a step of mounting a jig (40) for closing the gap (17) communicating with the groove (12) on the iron core; a step of dripping molten resin onto at least one of the inside and the outside of a core (11) of a stator assembly (10) in the radial direction in a vacuum state; and a step of returning the stator assembly (10) into the atmosphere, the stator assembly being dripped with the molten resin.

Description

Resin molding method, jig, and resin molding apparatus

Technical Field

The present invention relates to a method of resin-molding a stator assembly having a winding wound around a core, a jig used in the method, and a resin molding apparatus.

Background

In general, a rotating electrical machine such as a motor includes a stator and a rotor provided in the stator. The stator is formed by winding a coil around an annular iron core, and when a current flows through the coil, a magnetic force is generated to attract or repel the stator and the rotor to rotate the rotor provided in the stator.

Generally, a stator is a structure in which a stator assembly having a core around which a winding is wound is resin-molded, and insulation, heat dissipation, strength, and the like of the stator are secured by resin molding. As an apparatus for resin molding a stator assembly, for example, an apparatus described in patent document 1 is provided. The device includes: a vacuum tank; a rotary table rotating in the vacuum chamber; a double-layer cylinder supported by the rotary table and used for inserting the stator assembly; and a feeder for feeding a molding liquid including a molten resin to the stator assembly from above.

When resin molding is performed using the device described in patent document 1, the stator assembly is inserted into the double-layer cylinder such that the axial direction is the vertical direction. At this time, the slots of the core around which the windings are wound extend in the axial direction. The molding liquid is dropped vertically downward from the upper surface of the feeder perpendicular to the axis of the stator assembly while rotating the rotary table while the inside of the vacuum tank is kept in vacuum. The molding liquid penetrates from the upper surface of the stator assembly to the lower surface thereof in the groove by the gravity of the molding liquid, and resin molding is performed.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2005-218292

Disclosure of Invention

Technical problem to be solved by the invention

In recent years, motors called in-wheel motors and traction motors have been developed as motors used in electric vehicles and hybrid vehicles, for example. In the core of such a motor, the slots do not extend in the axial direction, but extend in the radial direction, i.e., in the direction orthogonal to the axial direction.

On the other hand, in the device described in patent document 1, the stator assembly is inserted into the double-layer cylinder so that the axial direction is the vertical direction, and the molten resin penetrates into the grooves extending in the vertical direction by the action of gravity, but in the stator assembly of the motor as described above in which the grooves do not extend in the vertical direction, there is a problem that the molten resin cannot penetrate into the grooves.

The present invention has been made in view of the above problems, and an object thereof is to provide a method, a jig, and a resin molding apparatus for resin molding a stator assembly having a core in which slots extend in a radial direction.

Means for solving the problems

The resin molding method of the present invention is a method of resin molding a stator assembly in which a winding is wound around an annular core, the core including: a plurality of grooves that are open at an outer circumferential surface and an inner circumferential surface and extend in a radial direction; and a gap communicating with the groove at the first face, the resin molding method including: a step of attaching a jig for closing the gap to the stator assembly; dropping a molten resin onto at least one of an outer side and an inner side of the core of the stator assembly in a radial direction in a vacuum state; and returning the stator assembly, on which the molten resin is dropped in a vacuum state, to an atmospheric state.

In the annular core of the stator assembly, a plurality of slots extend radially, and windings are wound around the slots and protrude from openings in the outer and inner circumferential surfaces of the slots. The annular core has a gap communicating with the slot at the first surface. In the case of performing resin molding of such a stator assembly, first, a jig is attached to the core to close the gap, and then molten resin is dropped from above to at least one of the winding outside the outer peripheral edge and the winding inside the inner peripheral edge in the radial direction of the core in a vacuum state. Then, the stator assembly dropped with the molten resin is returned to the atmospheric state. Then, the molten resin is drawn from the openings provided on the inner and outer sides in the radial direction by the pressure difference between the inside of the vacuum tank and the atmosphere, and is impregnated into the inside of the vacuum tank. In this case, since the gap communicating with the groove is sealed by the jig, air does not enter the groove from the gap before the molten resin, and the molten resin is reliably impregnated into the groove.

According to the method of the present invention, resin molding can be performed on the stator assembly having the core in which the slots extend in the radial direction.

In a preferred embodiment, the jig used in the resin molding method includes an abutment surface having a size corresponding to the first surface of the annular core and abutting against the first surface of the core so as to close the gap.

Preferably, the jig of the above embodiment has a positioning ridge on the abutment surface.

Preferably, the jig of the above embodiment has a sealing means for sealing the gap.

The sealing unit is made of, for example, rubber attached to the jig.

Another embodiment of the present invention provides a resin molding apparatus for resin-molding a stator assembly having a ring-shaped core around which a winding is wound, the core including: a plurality of grooves that are open at an outer circumferential surface and an inner circumferential surface and extend in a radial direction; and a gap communicating with the groove at the first surface, the resin molding apparatus including: a clamp mounted to the core and blocking the gap; a vacuum processing chamber that performs a process of dropping a molten resin onto at least one of an inner side and an outer side in a radial direction of a core of the stator assembly, the stator assembly having a gap between the cores closed by the jig being placed in a vacuum state; a nozzle provided in the vacuum processing chamber and configured to drip the molten resin toward the stator assembly; and a valve for returning the inside of the vacuum processing chamber to an atmospheric state.

Effects of the invention

According to the present invention, resin molding can be performed on a stator assembly having a core in which slots extend in the radial direction.

Drawings

Fig. 1 is a front view showing a schematic configuration of a resin molding apparatus according to an embodiment of the present invention, and is a view showing a stator assembly in cross section;

fig. 2 is a plan view of a stator assembly molded by the resin molding method of the present invention;

fig. 3 is a perspective view of a core of a stator assembly molded by the resin molding method of the present invention;

fig. 4 is a plan view (a), a bottom view (B), and a cross-sectional view (C) of the clip of the present invention.

Description of the reference numerals

10 stator assembly

11 iron core

12 groove

17 gap

18 first side

23 winding

30 casing

40 clamp

42 abutting surface

43A, 43B ridge

50 resin molding device

51 vacuum processing chamber

52 nozzle

55 atmosphere opening valve

Detailed Description

Embodiments of the present invention will be described with reference to the accompanying drawings.

The resin molding method of the present invention is performed using a jig 40 shown in fig. 4, and resin molding is performed on a stator assembly 10 in which a coil 23 is wound around an annular core 11.

First, a stator assembly 10 to which the resin molding method of the present invention is applied will be described. The stator assembly 10 is used for an in-wheel motor, for example, and includes an annular core 11 and a winding 23 wound around the core 11. As shown in fig. 3, a plurality of slots 12 are formed in the core 11. A plurality of slots 12 are provided along the circumferential direction, each slot 12 extends in the radial direction, and

openings

12a, 12b of the slot 12 are formed in the outer circumferential surface 20 and the inner circumferential surface 21 of the annular core 11.

Each slot 12 is a space surrounded by a disc-shaped yoke 13 and a tooth 14. The plurality of teeth 14 are provided on one surface of the yoke 13 in the circumferential direction, and each tooth 14 extends in the radial direction. The tooth portion 14 has a T-shaped cross section and includes a main body 15 and a tip portion 16 provided at the tip of the main body 15 and having a width larger than that of the main body 15 in the circumferential direction. Gaps 17 are formed between the tip portions 16 of the adjacent teeth 14, and the gaps 17 communicate with the slots 12. The main body 15 and the tip end 16 of the tooth 14 have a circumferential width that is narrower radially inward than radially outward, so that the circumferential widths of the groove 12 and the gap 17 are constant. The upper surface of the core 11 shown in fig. 3, that is, the surface formed by the tip portions 16 of the teeth 14 and the gaps 17 is referred to as a first surface 18 of the core 11, and the lower surface of the core 11 shown in fig. 3, that is, the surface of the yoke 13 opposite to the surface provided with the teeth 14 is referred to as a second surface 19 of the core 11.

The winding 23 is wound around the tooth 14 and the slot 12 and protrudes from the

openings

12a and 12b on the radially outer and inner sides of the slot 12. The portion of the winding 23 protruding from the outer opening 12a is referred to as an outer winding 23a, and the portion of the winding 23 protruding from the inner opening 12b is referred to as an inner winding 23 b.

The stator assembly 10 is housed in an annular housing 30 having a hollow portion 31, and the resin molding method of the present invention is performed. The housing 30 has a bottom and an open top, and the stator assembly 10 is housed in the housing 30 such that the second surface 19 of the core 11 abuts against the bottom surface of the housing 30 and the gap 17 provided in the first surface 18 of the core 11 faces the opening 30a of the housing 30.

As shown in fig. 4, the jig 40 has a ring member 41 made of a rubber member. The annular member 41 has an abutment surface 42 set to a size corresponding to the first surface 18 of the core 11, and the abutment surface 42 abuts against the first surface 18 of the core 11 to close and seal the gap 17 communicating with the slot 12. The

projections

43A and 43B for the positioning jig 40 are provided so as to project over the entire circumference on the outer and inner peripheral edges of the contact surface 42 of the annular member 41, and the distance L1 between the inner walls of the

projections

43A and 43B is set to be substantially the same as the distance L2 between the outer and inner peripheral edges of the core 11. Therefore, when the contact surface 42 of the annular member 41 is brought into contact with the first surface 18 of the core 11, the inner walls of the

respective protrusions

43A and 43B of the annular member 41 are brought into contact with the outer circumferential surface 20 and the inner circumferential surface 21 of the core 11, thereby preventing the jig 40 from being displaced from the core 11. The

ribs

43A, 43B may be provided only on one of the outer and inner peripheries of the abutment surface 42, or may be provided only on a part thereof instead of projecting over the entire periphery of the outer or inner periphery.

The annular member 41 is made of a rubber material as a sealing means. This enables the jig 40 to be brought into close contact with the core 11, thereby reliably closing the gap 17 of the first surface 18 of the sealed core 11. The annular member 41 of the jig 40 may be formed of a rubber member at least at the contact surface 42, and may be formed of a rubber sheet bonded to an annular base material made of metal and/or synthetic resin as a sealing means. Further, the annular member 41 may be made of an annular base material made of metal and/or synthetic resin, and may be a member having a gel-like adhesive made of synthetic resin as a sealing means and having an adhesive applied to the contact surface 42 of the base material. In this case, the adhesive has adhesiveness to such an extent that the jig 40 can be detached from the stator assembly 10 after resin molding.

A handle member 45 is attached to a surface of the annular member 41 opposite to the contact surface 42. The handle member 45 is a member in which a handle 45b is attached to an annular metal plate 45a, and the metal plate 45a is attached to a surface of the annular member 41 opposite to the contact surface 42 by an adhesive means such as an adhesive.

Next, a resin molding apparatus 50 for implementing the resin molding method of the present invention will be described. As shown in fig. 1, the resin molding apparatus 50 includes: a jig 40 attached to the stator assembly 10 as shown in fig. 4; a vacuum processing chamber 51 for placing the stator assembly 10 in which the gap 17 of the core 11 is sealed by the jig 40 in a vacuum state with the gap 17 facing upward, and for dropping molten resin for resin-molding the stator assembly 10 onto the stator assembly 10; and a nozzle 52 provided in the vacuum processing chamber 51, the nozzle 52 dropping the molten resin to the jig 40.

The vacuum processing chamber 51 is constituted by a vacuum chamber. A decompression device 54 such as a vacuum pump is attached to the wall of the vacuum processing chamber 51 via a valve 53, and the inside of the vacuum processing chamber 51 is decompressed by operating the decompression device. Further, an atmosphere opening valve 55 is attached to the vacuum processing chamber 51, and the atmosphere opening valve 55 is opened to open the atmosphere in the vacuum processing chamber 51. In the present specification, "vacuum" does not mean an absolute vacuum state, but means a state in a space filled with a gas having a pressure lower than atmospheric pressure.

The vacuum processing chamber 51 includes a support table 56 on which the stator assembly 10 is mounted, a nozzle 52, and a nozzle moving mechanism 57 for moving the nozzle 52 in the direction X, Y, Z. A support member 56a having a cylindrical shape is provided on the upper surface of the support table 56. When the stator assembly 10 is placed on the support base 56, the support member 56a is inserted into the hollow portion 31 of the housing 30 in which the stator assembly 10 is housed, and positions the stator assembly 10. The nozzle moving mechanism 57 is provided above the vacuum processing chamber 51, moves the nozzle 52 above the winding 23 located inside or outside the core 11 of the stator assembly 10, and moves up and down with respect to the winding 23. The nozzle moving mechanism 57 is not limited as long as it can move the nozzle 52 in the direction X, Y, Z, and may be configured by, for example, a linear motor, a ball screw, a nut member, a drive motor, or the like. The vacuum processing chamber 51 is not limited to the configuration in which the nozzle 52 is moved by the nozzle moving mechanism 57, and may be configured to have a support table moving mechanism for moving the support table 56 in the direction X, Y, Z, or may be configured to have a rotating mechanism for rotating the support table 56.

The nozzle 52, the nozzle moving mechanism 57, the pressure reducing device 54, and the like are connected to a control device, not shown, and the operation thereof is controlled.

Next, a method of resin molding the stator assembly 10 of the present invention will be described. First, a step of attaching the jig 40 to the core 11 is performed. The stator assembly 10 is housed in the case 30 with the first surface 18 of the core 11 facing the opening 30a side of the case 30. The operator brings the contact surface 42 of the jig 40 into contact with the first surface 18 of the core 11 of the stator assembly 10 through the opening 30a of the housing 30, thereby sealing the gap 17 formed in the first surface 18 of the core 11. At this time, the iron core 11 is covered with the jig 40 so that the inner walls of the ribs 43A and the inner walls of the ribs 43B of the annular member 41 of the jig 40 abut on the outer peripheral surface 20 and the inner peripheral surface 21 of the iron core 11, whereby the mounting position of the jig 40 is determined and the jig 40 is prevented from being displaced during the work. The process of attaching the jig 40 to the core 11 may be performed at any timing before or after the stator assembly 10 is placed on the support table 56 of the vacuum processing chamber 51.

Next, the operator inserts the support member 56a of the support table 56 of the vacuum processing chamber 51 into the hollow portion 31 of the housing 30, and places the stator assembly 10 on the support table 56 of the vacuum processing chamber 51 so that the gap 17 of the core 11 of the stator assembly 10 faces upward, that is, so that the jig 40 is positioned upward.

Then, after the vacuum processing chamber 51 is brought into a vacuum state by operating the decompression device 54, a step of dropping molten resin for resin molding the stator assembly 10 onto at least one of the inside and the outside of the core 11 of the stator assembly 10 in the radial direction is performed in the vacuum state. Specifically, by controlling the nozzle moving mechanism 57 by the control device, the nozzle 52 moves from a preset initial operation position to a position above the outer winding 23a protruding from the opening 12a of the slot 12 in the outer circumferential surface 20 of the core 11, and then descends such that the tip of the nozzle 52 is positioned directly above the outer winding 23a, and then starts ejecting the molten resin. The nozzle 52 moves in the circumferential direction along the outer winding 23a while dropping the molten resin.

After the nozzle 52 has rotated once over the outer winding 23a and a predetermined amount of molten resin has been dropped, the nozzle 52 is raised and moved upward above the inner winding 23b protruding from the opening 12b of the groove 12 in the inner circumferential surface 21. Then, after the nozzle 52 is lowered so that the tip thereof is positioned directly above the inner coil 23b, the molten resin starts to be discharged. The nozzle 52 moves in the circumferential direction along the inner winding 23b while dropping the molten resin. After the nozzle 52 has rotated once over the inner winding 23b and a predetermined amount of molten resin has been dropped, the nozzle 52 is raised and returned to the initial operating position. Molten resin is supplied from the nozzle 52 into the case 30 in an amount suitable for filling a space including a space inside the slot 12, a space where the coil 23a is located outside a space between the outer circumferential surface 20 of the core 11 and the case 30, and a space where the coil 23b is located inside a space between the inner circumferential surface 21 of the core 11 and the case 30. The molten resin may be dropped onto the inner winding 23b first, or may be dropped onto only one of the outer and

inner windings

23a and 23 b. The nozzle 52 may move over the

windings

23a and 23b by one or more revolutions to drop the molten resin.

Next, a step of returning the stator assembly 10 into the atmospheric state, in which the molten resin is dropped in the vacuum state, is performed. The atmosphere opening valve 55 of the vacuum processing chamber 51 is opened and instantaneously returned to the atmospheric pressure. Molten resin is introduced from the

openings

12a, 12b of the slot 12 of the stator assembly 10 by the pressure difference between the inside of the slot 12 in the vacuum state and the atmosphere, and the inside of the slot 12 is impregnated with the molten resin. At this time, since the gap 17 communicating with the tank 12 is sealed by the jig 40, air is not introduced into the tank 12 prior to the molten resin, and the molten resin can be reliably impregnated into the tank 12.

While the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.

For example, a projection bar having a length and a width corresponding to the gap 17 of the core 11 may be provided at a position corresponding to the gap 17 of the core 11 of the stator assembly 10 on the contact surface 42 of the annular member 41 of the jig 40. When the jig 40 is attached to the stator assembly 10, the projected bars are fitted into the gaps 17 of the core 11, and the gaps 17 can be more reliably sealed.

Claims

1. A resin molding method for resin-molding a stator assembly having a ring-shaped core around which a winding is wound, wherein,

the iron core has: a plurality of grooves that are open at an outer circumferential surface and an inner circumferential surface and extend in a radial direction; and a gap communicating with the groove at the first face,

the resin molding method includes:

a step of attaching a jig for closing the gap to the stator assembly;

dropping a molten resin onto at least one of an outer side and an inner side of the core of the stator assembly in a radial direction in a vacuum state; and

and returning the stator assembly, on which the molten resin is dropped in a vacuum state, to an atmospheric state.

2. A jig used in the resin molding method according to claim 1, wherein,

the jig includes an abutting surface having a size corresponding to the first surface of the core and abutting against the first surface of the core in a manner of closing the gap.

3. The clamp of claim 2,

the contact surface has a positioning protrusion.

4. The clamp of claim 2 or 3,

the contact surface has a sealing means for sealing the gap.

5. A resin molding apparatus for resin-molding a stator assembly having a ring-shaped core around which a winding is wound, wherein,

the resin molding apparatus includes:

a clamp mounted to the core and blocking the gap;

a vacuum processing chamber that performs a process of dropping a molten resin onto at least one of an inner side and an outer side in a radial direction of a core of the stator assembly, the stator assembly having a gap between the cores closed by the jig being placed in a vacuum state;

a nozzle provided in the vacuum processing chamber and configured to drip the molten resin toward the stator assembly; and

a valve for returning the interior of the vacuum processing chamber to an atmospheric state.