Patent Application
20050116572
1. Field of the Invention
The present invention relates to a rotating electrical unit and method of its production, particularly to a production method of the rotating electrical unit having a process for installing a coil preformed into a designed shape in a stator core.
2. Description of the Related Art
A rotating electrical unit has been conventionally and widely used in various fields. Here, the rotating electrical unit, including a motor and a generator, is used, as example and not limited to, as a drive motor for the compressor of an air conditioner, a drive motor for an electric automobile including a hybrid automobile and the generator for an automobile.
The rotating electrical unit is generally provided with a coil for generating a magnetic field (while in a generator, a coil for generating electromotive force in accordance with the change of flux). A simplified production process for the coil will gain a various benefits such as a production cost reduction of the rotating electrical unit. Hence, those methods described in the patent documents 1 through 4 listed below are known as techniques for simplifying the production process of a coil for the rotating electrical unit.
In the production method described in the patent documents 1 and 2, first, a conductor wire is wound in a ring for a plurality of turns as shown in
Also in the patent document 3, a production method in which a coil preformed into a designed shape is prepared for inserting into the slots of a stator core. However, in the production method described in the patent document 3, the pole-specific coils are preformed for each of individual poles and those coils are inserted into each one set of the corresponding slots. Alternatively, in the production method described in the patent document 4, a plurality of pine needle shaped conductors, called segment coils, are inserted into a set of corresponding slots, and a coil is formed by connecting those conductors one after another. Also known as other related techniques are given in the patent documents 5 and 6.
[Patent Document 1]
Japanese patent laid-open application publication 2002-209358 (FIGS. 6 and 7, paragraphs 0013 through 0015)
[Patent Document 2]
Japanese patent laid-open application publication 10-14149 (FIGS. 1 and 2, paragraphs 0007 through 0010)
[Patent Document 3]
Japanese patent laid-open application publication 2003-153478 (FIG. 4, paragraphs 0012 through 0014)
[Patent Document 4]
Japanese patent laid-open application publication 2001-37132 (FIGS. 2 through 6)
[Patent Document 5]
Japanese patent laid-open application publication 10-271733
[Patent Document 6]
Japanese patent laid-open application publication 2000-69700
Incidentally, a rotating electrical unit is required not only to be produced in a simple process as described above, but also have a high efficiency thereof. Note that the efficiency of a rotating electrical unit increases as the conductor wires constituting a coil is wound more closely. That is, the efficiency of a rotating electrical unit increases with the lamination factor of the conductor wires in a slot housing the coil. Here, the lamination factor of the conductor wires in a slot is defined as a ratio of “the sum of each cross-sectional area of a plurality of the conductor wires housed in the slot” to “the cross-sectional area of the slot.”
Whereas those conventional rotating electrical units produced by the processes such as the above mentioned process, in which the coils preformed into a designed shape is inserted into the slot of a stator core, have not necessarily achieved high lamination factor in the respective slots. In other words, it has conventionally been difficult to obtain a simplification of the production process while increasing the efficiency of a rotating electrical unit by improving the lamination factor of the conductor wires in a slot.
Meanwhile, in the motor noted in the patent document 3, there are problems such as: (1) being unable to form coils in three or more slots continuously; (2) ending up with a large coil end for insertion due to the coil end being stacked together in one side of the core; (3) requiring a special tool for forming coils into a particular shape and an apparatus for installing the coil in a stator; and (4) being limited to adopt it for a stator having semi-closed slots.
On the other hand, in the motor noted in the patent document 4, since the plurality of the segment coils have to be welded together one after another for forming a coil, the production process becomes complicated in addition to a reduced efficiency of the motor itself due to a loss in the welded points. Additionally, the number of the coil turns and slots need to be increased for a usage under high voltages, thereby reducing the productivity and the efficiency of the motor itself. Furthermore, it is difficult to increase the number of the coil turns, turn by turn, due to its coil layout, hence there is a limited freedom in designing a product.
The objective of the present invention is to provide a rotating electrical unit having a simple production process and a high efficiency, and its production method.
A production method of a rotating electrical unit according to the present invention includes the first process forming a coil by winding a flat conductor wire in a plurality of turns around a pre-forming member having a designed shape, and the second process producing a stator by inserting the coil into three or more slots provided in a stator core of a rotating electrical unit so as to cross over the plurality of slots, wherein, in the first process, the flat conductor wire is wound around the pre-forming member so that a cross-section shape of the coil is matched approximately with that of the slot.
According to the invention, since the coil pre-formed to a designed shape is inserted into three or more slots so as to cross over the plurality of slots, the production process is simple. And since the flat conductor wire is used as a conductor wire for constituting the coil, the lamination factor (or density) of the conductor wires in a slot is increased, thereby improving the efficiency of a rotating electrical unit. Moreover, since the cross-section shape of the coil is matched approximately with that of the slot, the lamination factor of the conductor wires in a slot is further increased, thereby improving the efficiency of the rotating electrical unit as that much.
In the second process of the above described production process, the coil may be inserted into three or more slots so as to cross over the plurality of slots and form wave winding. According to the invention, a fewer number of process is required, and a smaller loss in the coil itself is performed as compared to the production process in which a plurality of segment coils are inserted into the corresponding slots and then connected with each other.
And in the production method described above, the first process may include the first sub-process for winding n-turns of said flat conductor wire so that the flat conductor wire is wound sequentially in n-columns lined up in the first direction while being pressed against a pressure surface of the pre-forming tool, the second sub-process for winding n-turns of the flat conductor wire so that the flat conductor wire is wound sequentially in n-columns lined up in the direction opposite to the first direction stacking outward on the flat conductor wire wound in the first sub-process, and the third sub-process for alternating the first sub-process and the second sub-process so that the flat conductor wire is wound further stacking outward on the flat conductor wire wound in the first and second sub-processes. Furthermore, the flat conductor wire may be further wound following the third sub-process so as to make the cross-section shape of the coil a trapezoid. According to these inventions, the flat conductor wire constituting the coil is always adjacent to the one previously wound, making the alignment of wires constituting a coil minimally disturbed, resulting in higher lamination factor of the conductor wires in a slot and improving the efficiency of a rotating electrical unit.
Furthermore, in the production method as described above, a plurality of operations for winding the flat conductor wire in a plurality of turns may be performed in the first process so as to stack in the direction vertical to a surface of the pre-forming member. According to the invention, since there is less number of times in which the alignment of conductor wires constituting a coil is disturbed, the lamination factor of the conductor wires in a slot is higher as that much. Note that, if the number of turns wound in the plurality of operations above is made the same for each winding operation, the cross-section shape of the coil becomes a rectangle, while if the number of turns wound in the plurality of operations above is sequentially incremented one by one, the cross-section shape of the coil becomes a trapezoid.
Furthermore in the production method as described above, the surface of a pre-forming member is featured stepwise, and the flat conductor wire is wound in the first process so that the number of turns of the flat conductor wire being stacked in the direction vertical to each step of the surface of the pre-forming member may increment by a predefined number for respective step. According to the invention, the cross-section shape of the coil becomes a trapezoid.
Furthermore in the production method as described above, the pre-forming member comprises a straight area and a curved area, and the coil comprises a plurality of straight portions formed by using the straight area of the pre-forming member, and a curved portion formed by using the curved area of the pre-forming member. Each of the plurality of straight portions of the coil is inserted into the corresponding slot, and the curved portion of the coil is allocated so that the curved portion of the coil crosses over the slots each inserted with the straight portion of the coil in the second process. And if the flat conductor wires are not allowed to cross with each other in the straight portion of the coil in the first process, the alignment of the conductor wires in a slot is secured. And if the stator core is disposed for installing a plurality of coils produced in the first process, each curved portion may be respectively formed prior to the second process so that coils do not interfere with one another when each of the plurality of coils is installed in the stator core. This makes the operation for inserting the coils into corresponding slots easy.
Furthermore in the production method as described above, after the coil is treated with an insulation processing, the insulated coil is inserted into the slots in the second process. According to the invention, there is no need to pre-install an insulation sheet in the slot. And with the pre-treatment of an insulation processing for the coil, the alignment of the flat conductor wires is hard to disturb when inserting the coil into the corresponding slots.
A rotating electrical unit according to the invention comprises a stator having a stator core installed with the coils, wherein the coil consists of the flat conductor wires, the cross-section shape of the coil is configured matching approximately with that of slots provided in the stator core. The stator is produced by inserting the coil into three or more slots provided in the stator core so as to cross over the plurality of slots.
In the invention, since a coil is formed to a designed shape by using the flat conductor wire and a stator is produced by inserting the coil in the corresponding slots in the stator core of a rotating electrical unit, it is possible to provide the rotating electrical unit by a simple production process and with a high efficiency thereof. In accordance with this, it is also possible to make a rotating electrical unit compact.
A rotating electrical unit according to the present invention includes a stator and a rotor as a common rotating electrical unit and the invention has no specific characteristics in the rotor structure. Accordingly a description of the rotor is omitted herein. Also, in the production method of the rotating electrical unit according to the present invention, the premise is that the production processes except for that of a stator can be accomplished by the conventional techniques. Note that the following specification is described by choosing a 3-phase rotating electrical unit having 6 poles in each phase as a case for description.
The coil pre-forming tool 20 comprises a main body (i.e., a forming member) 21, a straight-portion pressure member 22 and a curved-portion pressure member 23. The main body 21 comprises the straight portions protruding in three radial directions, the convex curved portions featured at the end of each straight portion, and the concave curved portions provided nearby the base of the straight portions. The straight-portion pressure member 22, being set aside of the straight portion of the main body 21, is disposed for pressing the conductor wires wound around the main body 21 against the corresponding straight portion. Meanwhile, the curved-portion pressure member 23, being set aside of the concave curved portion of the main body 21, is disposed for pressing the conductor wires wound around the main body 21 against the corresponding concave curved portion.
By winding a conductor wire around the main body 21 in a plurality of turns, a coil to be installed in the stator core 10 is formed, which is called the first process. In this process, the conductor wire, having been wound around the main body 21 in such a way that it passes between the main body 21 and the straight portion pressure member 22 and between the main body 21 and the curved-portion pressure member 23, are formed into the same shape as the outer contour shape of the main body 21. Note that a conductor wire used in the present embodiment is a “flat conductor wire,” whose cross-section shape is either a rectangle or an approximate rectangle, which will be described in detail later.
Then the coil 30 thus preformed is further formed into as shown in
The coil 30 formed into the shape as shown in
The convex curved portions 32a through 32c of the coil 30, as shown in
Then, after the coil 30 is installed in the inner ring member 11, the outer ring member 12 is installed so as to enclose the inner ring member 11, thereby the stator for a rotating electrical unit being comprised.
As a result, a stator is completed comprising distributed wave winding in which the coil is inserted into three or more slots (six slots in the present embodiment) with each coil crossing over a plurality of slots. Here, for example, the coil winding is done in the following route: the upper end of slot 13d→lower end of slot 13d→lower end of slot 13g→upper end of slot 13g→upper end of slot 13j→lower end of slot 13j→lower end of slot 13m→upper end of slot 13m→upper end of slot 13p→lower end of slot 13p→lower end of slot 13a→upper end of slot 13a→upper end of slot 13d and so on.
The coil 30 may be treated with an insulation processing before the coil 30 is inserted into the slots of the stator core 10. The insulation processing thereof may be, for example, applied to the straight portion (or both the straight and curved portions) of the coil 30 by covering with insulation paper, insulation film or plastic materials. With such processing, the insulation between the coil 30 and the stator core 10 is secured by merely inserting the insulation-processed coil 30 into the corresponding slots, eliminating a need to insert an insulation paper or the like into each slot of the stator core 10 beforehand. Also, an insulation processing for the coil 30 as above described at the time when it is configured as shown in the
For a conductor wire constituting a coil, a “round conductor wire” whose cross-section shape being a circle is generally used. In particular, the round conductor wire is basically used for producing a rotating electrical unit in the production process in which coil preformed into a designed shape is inserted into the slots of the stator core in consideration of an ease of the coil forming. However, forming a coil by using the round conductor wire causes the inevitable gaps among the wires, as shown in
On the other hand, in the rotating electrical unit according to the present embodiments of the invention, a “flat conductor wire” whose cross-section shape being a rectangle or approximate rectangle is used for a conductor wire constituting a coil. Here, configuring a coil by the flat conductor wire makes it possible to align the conductor wires without causing gaps in the slot as shown in
Meanwhile, in the production method according to the present embodiments of the invention as described referring to
Note that, in the case of using round conductor wire for constituting a coil, aligning the round wires is difficult when forming them into a particular shape as compared to the flat rectangular wires, which makes it difficult to pre-form the coil with a round wire so that the cross-section shape of the coil is matched with that of the slot.
The preferred embodiments of producing the coil 30 will then be described. The coil 30 is, as shown in
The coil 30 is pre-formed by winding the flat conductor wire around the main body 21 of the coil pre-forming tool 20 for a plurality of turns while aligning the flat conductor wire. Then the coil 30 pre-formed as such is formed as shown in
In the embodiment 1, first, the flat conductor wire is wound in three turns around while lining up the wire side by side along the main body 21 of the coil pre-forming tool 20 (called the first sub-process). Note here that “the first direction” specified in the claim, in
And likewise, the first and second sub-processes are alternately performed so as to wind the flat conductor wire further on the outside of previously stacked wires (called the third sub-process). In such a way, the flat conductor wire is wound in the seventh through the 21st turns.
Subsequently, in order to make the cross-section shape of the coil 30 a “trapezoid,” the 22nd turn of the flat conductor wire is stacked on the 20th turn thereof, the 23rd turn of the flat conductor wire on the 19th turn thereof, and 24th turn of the flat conductor wire on the 23rd turn thereof. As a result, as shown in
Note that the cross-section shape of the coil 30 can be changed by the cross-section shape of the flat conductor wire, the number of turns of winding the flat conductor wire around the coil pre-forming tool 20, the number of columns and rows, i.e., in the vertical and horizontal directions on the paper as seen in
Now, for example, in the case of forming a coil as shown in
Incidentally, in general, configuring a coil by winding a conductor wire in a plurality of turns, the wires sometimes cross with one another in a space of the coil where a disturbance in the alignment of the conductor wires will result.
If crossing between the flat conductor wires is inevitable while winding the wire around the main body 21 of the coil pre-forming tool 20, a care must be taken to have the wires cross in a curved portion (for example, a convex curved portion) of the main body 21, in order to avoid crossing the flat conductor wires at least at a straight portion of the main body 21, thereby maintaining the alignment of the flat conductor wires in the straight portions 31a through 31f of the coil 30. In other words, the flat conductor wires constituting the coil 30 maintain the alignment thereof at least within the slots of a stator core 10.
If the flat conductor wire is wound in the above described order, two wires cross with each other at the start of 4th, 7th, 10th, 13th, 15th, 18th, 21st and 24th turns, for example. That is, for instance, the flat conductor wire comes to cross at the beginning of the 4th turn, riding diagonally over the flat conductor wire laid at the 3rd turn thereof. Except that, if the flat conductor wire is wound in the order as shown in
In the embodiment 3, the process for winding the flat conductor wire in a predefined number of turns is done a plurality of times so as to stack vertically to the pressure surface 24 on the main body 21 of the coil pre-forming tool 20. In this instance, first, the flat conductor wire is wound so as to stack in the first through the ninth turns of winding the flat conductor wires in the direction of the outer circumference. Then, the 10th through 17th turns of the flat conductor wires are wound in adjacent to the stack of the flat conductor wires wound in the first through the ninth turns. The 18th through 24th turns of the flat conductor wires are further wound in adjacent to the 10th through 17th turns thereof.
Also in the embodiment 3, the same as in the embodiment 1, the pressure surface 24 of the coil pre-forming tool 20 is featured stepwise, as shown in
Note that the number of winding turns stacking the flat conductor wires on the respective step can be changed to a predefined decrement, e.g., “2,” in which case the cross-section shape of a coil becomes also a “trapezoid.”
Also in the embodiment 3, in the example shown by
The coil 30 formed by using the coil pre-forming tool 20, and having been configured as shown in
First, each of the straight portions of the U-phase coil 30U is inserted into the corresponding slots 13a, 13d, 13g, 13j, 13m and 13p, as shown in
Then, each of the straight portions of the V-phase coil 30V is inserted into the corresponding slots 13b, 13e, 13h, 13k, 13n and 13q, as shown in
Subsequently, each of the straight portions of the W-phase coil 30W is inserted into the corresponding slots 13c, 13f, 13i, 13l, 13o and 13r, as shown in
As such, by the production method according to the present embodiment, installing the coils 30U, 30V and 30W in the stator core 10 obtains a distributed and wave winding coil for each phase.
Note that the cross-over portion, i.e., the convex and concave curved portions, of each of the coils 30U, 30V and 30W maybe preformed so as to be placed as described above when installing each coils in the stator core 10. Furthermore, it is desirable to place each of the coils 30U, 30V and 30W so that each cross-over portion does not contact with each other, thus eliminating a need of an insulation processing between each coil.
Further note, the configuration of each coil 30U through 30W is not limited as shown in
As described above, a rotating electrical unit according to the present embodiments, since the preformed coils are inserted into the corresponding slots in the stator core, while the flat conductor wires are used as a conductor wire constituting the coil, the efficiency of the rotating electrical unit is improved as well as the coil winding process is simplified.
The coil according the present embodiment is not a segment coil as described in the patent documents 3 and 4 quoted above, it is possible to obtain a higher freedom in designing the number of turns thereof, and it requires no increase in the number of slots for applying to a rotating electrical unit in a high voltage specification.
Furthermore, since the stator is obtained by inserting the preformed coil into the corresponding slots, a resultant smaller coil end gains a compact, high efficiency rotating electrical unit.
Note that a rotating electrical unit according to the present invention is not limited to the embodiments as described above. For example, in the embodiments described above, a stator core comprises an inner ring member and an outer ring member, the present invention is not limited as such. That is, a stator core, for example, can be one having slots opening toward the center of the stator, in this case preformed coils will be inserted into the corresponding slots from inside of the stator core in a way expanding the diameter thereof. In this case, the cross-section shape of each slot is basically a “rectangle” in this application.
Furthermore, a rotating electrical unit is not limited to having three phases, or each phase consisting of “six” poles. For example, if the number of poles for each phase is “four”, a coil is formed by the flat conductor wires in the shape as shown in
Still furthermore, in the embodiments described above, the cross-over portions of the coil, i.e., the convex curved portions 32a through 32c, are formed in curve by the convex curved portions of the main body 21 in the coil pre-forming tool 20 as shown in
Yet furthermore, in the embodiments described above, although the conductor wire is wound directly around the coil pre-forming tool 20, it is not limited as such. That is, it may be such that a ring coil is formed having conductor wires aligned together as described above, and the ring coil is then formed by the coil pre-forming tool 20 as shown in
| Number | Date | Country | Kind |
|---|---|---|---|
| 2003-359571 | Oct 2003 | JP | national |
