The present invention relates to a rotating machine, an insulator for the rotating machine, and a slot liner used in the rotating machine.
A rotating machine such as a motor closely related to industry and daily living is infrastructure equipment sustaining modern society. Among such rotating machines, in a rotating machine operated at a relatively low voltage, magnet wire is used for coil winding. When a coil is incorporated into a slot formed in a stator core, necessary insulation performance is secured by installing an insulator called a slot liner in the slot so as to cover magnet wire and fastening the magnet wire, the slot liner, and the stator core with varnish (refer to Patent Literatures 1 and 2 for example).
Meanwhile, a hybrid vehicle and an electric vehicle become widespread for the conservation of the global environment and a rotating machine employing such an insulation system as stated above is used as a drive source for such a vehicle. A rotating machine for an automobile tends to cause larger vibrations during operation in comparison with a rotating machine used at home or a factory because vibrations by running are added to the vibrations caused by electromagnetic force and rotating eccentric force of the rotating machine. Consequently, in the case where a force accompanying vibrations is added to a rotating machine employing an insulation system formed by fastening magnet wire and a slot liner with varnish, the magnet wire vibrates if a fastened part exfoliates and hence that may undesirably damage the insulation layer of the magnet wire mechanically and lead to electrical breakdown.
According to the first embodiment of the present invention, in a rotating machine comprising a stator including a stator core having a plurality of slots arrayed in the circumferential direction, a plurality of conductors for stator winding wire inserted respectively into the slots, and slot liners comprising a sheet-shaped insulator surrounding the conductors for stator winding wire and a rotor rotatably arranged concentrically with the stator, the slots being filled with an electrically insulative resin, concavo-convex is formed on both the top and bottom surfaces of the slot liners.
According to the second embodiment of the present invention, in a rotating machine according to the first embodiment, it is preferable that: the slot liners are installed respectively from ends to the other ends of the slots extending from an end to the other end of the stator core in the axial direction; and concave parts constituting the concavo-convex communicate from the ends to the other ends of the slots.
According to the third embodiment of the present invention, in a rotating machine according to the second embodiment, it is preferable that concave parts and convex parts constituting the concavo-convex extend respectively in the axial direction of the stator core.
According to the fourth embodiment of the present invention, in a rotating machine according to the second embodiment, it is preferable that concave parts and convex parts constituting the concavo-convex extend respectively in the manner of being skewed to the axial direction of the stator core.
According to the fifth embodiment of the present invention, in a rotating machine according to the third or fourth embodiment, it is preferable that the concavo-convex has a wavy concavo-convex shape or an embossed concavo-convex shape.
According to the sixth embodiment of the present invention, in a sheet-shaped insulator for a rotating machine used for the electrical insulation of stator winding wire of the rotating machine: the insulator is an insulating sheet comprising at least either of a polymer film and fibrous nonwoven paper; and concavo-convex is formed on both the top and bottom surfaces of the insulating sheet.
According to the seventh embodiment of the present invention, in an insulator for a rotating machine according to the sixth embodiment, it is preferable that the concavo-convex has a wavy concavo-convex shape or an embossed concavo-convex shape.
According to the eighth embodiment of the present invention: a slot liner is arranged in a slot formed in a stator of a rotating machine and formed by folding an insulator for a rotating machine according to the sixth or seventh embodiment into a cylindrical shape; and concave parts and convex parts of the concavo-convex extend in the axial direction of the cylindrical slot liner.
The present invention makes it possible to improve the insulation reliability of a rotating machine.
Embodiments according to the present invention are hereunder explained in reference to drawings.
As shown in
Several tens of the slots 31 and the stator coils 41 are usually allocated respectively at equal intervals in the circumferential direction of the stator 30 but here only parts of them are shown in the figures. Here, although four stator coils 41 having a rectangular sectional shape are incorporated into a slot 31 in the example shown in
Here, electric wire produced by coating the surface of a conductor having a rectangular section generally called rectangular magnet wire with an enamel film is preferably used as the stator coils 41a, 41b, 41c, and 41d. Further, insulating paper called laminated insulating paper formed by sticking heat-resistant fibrous nonwoven paper together on both the surfaces of a polymer film is preferably used as the slot liners 1a and 1b. The slot liners 1a and 1b are formed by folding the laminated insulating paper.
The space of the slot 31 excluding the stator coils 41a to 41d and the slot liners 1a and 1b is filled with varnish 51 for insulation. The varnish 51 is a resin having electrical insulation and epoxy resin, heat-resistant alkyd resin, unsaturated polyester resin, etc. are used. The stator coils 41a to 41d and the slot liners 1a and 1b are fixed to the stator core 32 by hardening the varnish 51. A thermosetting resin that is in the form of a liquid when the slot 31 is filled and hardens by applying heat after the filling is preferably used as the varnish 51.
Although both the top and bottom surfaces of the slot liners 1a and 1b are described planarly in an abbreviated manner in
A gap between the slot liner 1a and a slot inner wall, a gap between the slot liner 1a and the stator coil 41, and a gap between adjacent slot liners are filled with varnish 51 respectively. A feature of the present embodiment is that both the top and bottom surfaces of the slot liners 1a and 1b have a concavo-convex shape and it is thereby possible to increase a contact area between the slot liners 1a and 1b and the varnish 51 in comparison with the case where the surfaces of a slot liner have a planar shape.
Meanwhile, as stated earlier, vibrations are generated by electromagnetic force varying temporally by the interaction of magnetic fields, vibrations accompanying rotation, and others in a stator coil of a rotating machine under operation. Further, a rotating machine mounted on a movable body such as an automobile undergoes vibrations from outside. Under such vibrations, the varnish 51 plays a role of fixing the stator core 32 and the stator coil 41 so as not to be displaced relatively. If the adhesive force of the varnish 51 is insufficient therefore, exfoliation occurs at an adhesive site by the electromagnetic force and inertial force accompanying the vibrations and the stator core 32 and the stator coil 41 slide and are displaced relatively. If such slide is repeated for a long period of time, mechanical damages are caused in the enamel film 43 of the stator coil 41 and necessary insulation performance may not be maintained undesirably.
The present inventors have found that the interface adhesive force between the hardened varnish 51 and the slot liners 1a and 1b is inferior to the interface adhesive force between the hardened varnish 51 and the magnet wire (stator coil 41) with regard to the exfoliation at the adhesive site during the course of evaluating the characteristics of an insulation system formed by fastening magnet wire and insulating paper constituting slot liners with varnish.
As shown in
Such difference in interface adhesive force has not heretofore been recognized. Since the insulation life of a rotating machine is dominated by a weakest part, in the case of using insulating paper having untreated (no concavo-convex) surfaces as a slot liner as usual, reliability is dominated by the insulation life of the insulating paper and varnish in spite of the fact that the insulation life of magnet wire and varnish has still allowance. In the present embodiment in contrast, since both the top and bottom surfaces of slot liners 1a and 1b have a concavo-convex shape, it is possible to: improve adhesive force further than the conventional case of not having concavo-convex as shown in
In the case of the insulating paper 61 shown in
It is possible to form insulating paper 61 having a surface shape shown in
Meanwhile, when the slot liner 1 is inserted into the slot 31, the folded insulating paper tries to restore the shape and hence the slot liner 1 may hardly be inserted because of friction against a slot inner wall or the like in some cases. Then in such a case, an arising problem is that the slot liner 1 is likely to buckle.
Furthermore, the extending direction of the concavo-convex nearly coincides with the slot extending direction R1 and the concave parts forming a varnish filling space pass through the slot 31 in the axial direction. As a result, in a succeeding varnish filling process, it is possible to: fill even the inside of the slot 31 with the varnish; and prevent a space not filled with the varnish from being generated. In general, the stator core 32 is arranged so that the axial direction may be the vertical direction and the slot 31 is filled with the varnish in the manner of dropping the varnish to a core end part. Since the concave parts of the slot liner 1 pass through the interior of the slot 31 in the axial direction, it is possible to: fill the slot 31 up to the back end with the varnish 51 without fail by making use of gravity; and prevent a varnish unfilled space from being generated.
In the case of a slot liner 100 having no concavo-convex as shown in
Here, although the apex of a convex part has a curved surface in the concavo-convex shape shown in
Further, in the case of a slot liner 1 shown in
Furthermore, since a concave part filled with varnish 51 is skewed to the slot extending direction, the effect of preventing a stator coil 41 and a slot liner 1 from being displaced in the axial direction is enhanced. Varnish 51 filling a space except a slot liner 1 and a stator coil 41 in a slot 31 comes to be a hardened solid resin by thermal hardening. The adhesive force of the hardened varnish 51 functions as a lock mechanism to prevent displacement of the slot liner 1 and the stator coil 41 in the axial direction, namely to prevent displacement by shear force trying to get out. In the configuration shown in
Here, although the case of using insulating paper 61 shown in
Here, although a sinusoidal shape is used as a concavo-convex shape in
Furthermore, although explanations have been made on the basis of the case of using rectangular wire having a rectangular section as a stator coil 41 in the above embodiments, a slot liner 1 according to the present embodiment can be applied to a slot liner formed in the manner of enveloping thick round wire and a slot liner formed in the manner of surrounding the circumference of a bundle of round wire. Moreover, a slot liner 1 according to the present embodiment may be applied to a stator coil not coated with enamel.
As stated above, in the present embodiment, in a rotating machine comprising a stator 30 including a stator core 32 having a plurality of slots 31 arrayed in the circumference direction and a plurality of stator coils 41 surrounded by slot liners 1 comprising a sheet-shaped insulator and inserted respectively into the slots 31 and a rotor 20 rotatably arranged concentrically with the stator 30, the slots 31 being filled with varnish 51, concavo-convex is formed on both the top and bottom surfaces of the slot liners 1. As a result, it is possible to: increase a contact area between the slot liners 1 and the varnish 51; and improve adhesive strength between the slot liners 1 and the varnish 51. Consequently, it is possible to: reduce the exfoliation at a contact surface caused by vibrations and the like; and improve insulation reliability.
Further, a slot liner 1 is installed from an end to the other end of each of slots 31 extending from an end to the other end of a stator core 32 in the axial direction and concave parts 61b constituting concavo-convex communicate from an end to the other end of each of the slots 31. By adopting such a configuration, it is possible to: fill the slots 31 up to the back ends in the axial direction with varnish 51 without fail; and prevent a varnish unfilled space from being generated.
Furthermore, by extending concave parts 61b and convex parts 61a constituting concavo-convex of a slot liner 1 respectively in the axial direction of a stator core 32 or extending them in the manner of being skewed in the axial direction, it is possible to increase strength against buckling deformation when the slot liner 1 is inserted into a slot 31. Here, in the case of such an embossed structure as shown in
Moreover, in a cross section perpendicular to the extending direction of concave parts 61b and convex parts 61a of a slot liner 1, by forming concavo-convex so as to have a wavy concavo-convex shape or an embossed concavo-convex shape (convex parts 611), it is possible to: prevent a wide region of the slot liner 1 from closely sticking to a slot inner wall and a stator coil 41; and prevent a region not filled with varnish from being generated.
In addition, in a sheet-shaped insulator (insulating paper 61) for a rotating machine used for electrical insulation of stator winding wire (stator coil 41) of the rotating machine, the insulator is an insulating sheet comprising at least either of a polymer film and fibrous unwoven paper and concavo-convex is formed on both the top and bottom surfaces of the insulating sheet. By installing such an insulating sheet in the manner of surrounding a stator coil 41 arranged in a slot 31 of a stator core 32, it is possible to improve the insulation performance of the rotating machine.
Her, the above explanations are only based on examples and the present invention is not limited to the above embodiments at all as long as the feature of the present invention is not damaged. For example, although a rotating machine of an inner rotor type is used for the explanations in the above examples, the present invention can be applied also to a rotating machine of an outer rotor type.
Although various embodiments and modified examples are explained heretofore, the present invention is not limited to the contents. Other embodiments conceivable in the scope of the technological thought of the present invention are also included in the present invention.
The contents disclosed in the following priority basic application are incorporated herein by reference. Japanese Patent Application No. 2011-139702 (filed on Jun. 23, 2011)
Number | Date | Country | Kind |
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2011-139702 | Jun 2011 | JP | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/JP2012/065344 | 6/15/2012 | WO | 00 | 12/3/2013 |