Rotor for dynamo-electric machine

The present invention provides a rotor for a rotary electric machine that suppresses the occurrence of winding disturbances in the process of winding a coil wire and has a coil field having a uniform outside diameter that is less likely to collapse.A coil field of a rotor coil is constructed by winding a coil wire having a circular cross section onto an outer circumference of a drum portion of a bobbin in multiple layers so as to make columns in each of the layers equal in number in an axial direction. Odd numbered layers of the coil field are constructed such that the coil wire is wound for approximately one turn around the drum portion in contact with an inner peripheral wall surface of a first flange portion of the bobbin, then wound into a plurality of columns in an axial direction such that the columns of the coil wire contact each other, and the coil wire in a final column forms a gap S relative to an inner peripheral wall surface of a second flange portion of the bobbin, and even numbered layers of the coil field are constructed such that the coil wire is wound for approximately one turn around the drum portion in contact with an inner peripheral wall surface of the second flange portion, then wound into a plurality of columns in an axial direction such that the columns of the coil wire contact each other, and the coil wire in a final column forms a gap S relative to an inner peripheral wall surface of the first flange portion. The gap S satisfies an expression D/4≦S≦D/2 relative to a diameter D of the coil wire.Thus, because the occurrence of winding disturbances in the process of winding the coil wire is suppressed, the coil wire can be wound into an aligned state, enabling a coil field that is less likely to collapse to be achieved, and the outside diameter of the coil field is made uniform, also preventing damage to an electrically-insulating coating resulting from contact with claw-shaped magnetic poles.

TECHNICAL FIELD

The present invention relates to a rotor for a rotary electric machine mounted to an automotive vehicle such as a passenger car, a truck, an electric train, etc., and particularly to a winding construction of a rotor coil wound onto a drum portion of a bobbin.

BACKGROUND ART

FIG. 17is a front elevation explaining a conventional method for manufacturing a rotor coil of a rotary electric machine such as that described in Japanese Patent Laid-Open No. HEI 6-181139 (Gazette), for example.

In this conventional method for manufacturing a rotor coil, as shown inFIG. 17, a bobbin1in which a pair of flanges1bare formed at two ends of a drum portion1ais mounted to a spindle2and rotated as indicated by the arrow. Then, a wire material4is paid out through a nozzle3and wound onto the drum portion1aof the rotating bobbin1. Here, the rotor coil is obtained by reciprocating the nozzle3in the direction of the arrows such that the wire material4is arranged in rows and wound into multiple layers on the drum portion1a.

However, in conventional methods for manufacturing rotor coils, no consideration has been given to relationships between axial dimensions of the drum portion1aand a diameter of the wire material4, positional relationships between the wire material4in radially-adjacent layers, etc. Thus, winding disturbances occur while winding the wire material4onto the drum portion1a.An outside diameter of a coil field constituted by the wound wire material4after completion of winding becomes uneven in an axial direction of the bobbin1as a result of these winding disturbances. As a result, one disadvantage has been that the wire material4positioned at the outermost circumference of the coil field where the outside diameter is enlarged may come into contact with an inner circumferential wall surface of a pole, damaging an electrically-insulating coating on the wire material4and giving rise to insulation failure. Another disadvantage has been that balance of a load acting on the wire material4is poor as a result of the winding disturbances, giving rise to collapse of the coil field after completion of winding.

DISCLOSURE OF INVENTION

The present invention provides a rotor for a rotary electric machine having a coil field having a uniform outside diameter that is less likely to collapse by constructing the coil field by winding a coil wire into multiple layers on a bobbin so as to make the number of columns in each of the layers equal and by prescribing a relationship between a gap between the coil wire and a flange portion of the bobbin and an array pitch of the coil wire to suppress the occurrence of winding disturbances in the process of winding the coil wire.

In order to achieve the above object, according to one aspect of the present invention, there is provided a rotor for a rotary electric machine in which a coil field of a rotor coil is constructed by winding a coil wire having a circular cross section onto an outer circumference of a drum portion of a bobbin in multiple layers so as to make columns in each of the layers equal in number in an axial direction. Odd numbered layers of this coil field are constructed such that the coil wire is wound for approximately one turn around the drum portion in contact with an inner peripheral wall surface of a first flange portion of the bobbin, then wound into a plurality of columns in an axial direction such that the columns of the coil wire contact each other, and the coil wire in a final column forms a gap S relative to an inner peripheral wall surface of a second flange portion of the bobbin, and even numbered layers of the coil field are constructed such that the coil wire is wound for approximately one turn around the drum portion in contact with an inner peripheral wall surface of the second flange portion, then wound into a plurality of columns in an axial direction such that the columns of the coil wire contact each other, and the coil wire in a final column forms a gap S relative to an inner peripheral wall surface of the first flange portion. The gap S satisfies an expression D/4≦S≦D/2 relative to a diameter D of the coil wire.

According to another aspect of the present invention, there is provided a rotor for a rotary electric machine in which a coil field of a rotor coil is constructed by winding a coil wire having a circular cross section onto an outer circumference of a drum portion of a bobbin in multiple layers so as to make columns in each of the layers equal in number in an axial direction. Odd numbered layers of this coil field are constructed such that the coil wire is wound for approximately one turn around the drum portion in contact with an inner peripheral wall surface of a first flange portion of the bobbin, then wound into a plurality of columns in an axial direction with a gap G between the coil wire, and the coil wire in a final column forms a gap S relative to an inner peripheral wall surface of a second flange portion of the bobbin, and even numbered layers of the coil field are constructed such that the coil wire is wound for approximately one turn around the drum portion in contact with an inner peripheral wall surface of the second flange portion, then wound into a plurality of columns in an axial direction with a gap G between the coil wire, and the coil wire in a final column forms a gap S relative to an inner peripheral wall surface of the first flange portion. The gap S satisfies an expression S=(D+G)/2 relative to a diameter D of the coil wire and the gap G.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the preferred embodiments of the present invention will now be explained with reference to the drawings.

FIG. 1is a cross section showing part of a rotor for a rotary electric machine according to Embodiment 1 of the present invention,FIG. 2is a perspective showing a bobbin used in the rotor for the rotary electric machine according to Embodiment 1 of the present invention,FIG. 3is a perspective showing a rotor coil installed on the bobbin in the rotor for the rotary electric machine according to Embodiment 1 of the present invention,FIG. 4is a perspective explaining a method for installing the rotor coil in the rotor for the rotary electric machine according to Embodiment 1 of the present invention, andFIGS. 5 to 7are process diagrams explaining the method for installing the rotor coil in the rotor for the rotary electric machine according to Embodiment 1 of the present invention.FIGS. 8 to 10are cross sections showing the rotor coil installed in the rotor for the rotary electric machine according to Embodiment 1 of the present invention,FIG. 8showing a case in which S>D/2,FIG. 9a case in which S=D/2, andFIG. 10a case in which S<D/4. Moreover, S is a gap between a coil wire15and an inner peripheral wall surface of first and second flange portions18and19in respective layers, and D is a diameter of the coil wire15.

A rotor10for a rotary electric machine, as shown inFIG. 1, is constituted by: a rotor coil11for generating a magnetic flux on passage of an electric current; and a pair of pole cores12disposed so as to cover the rotor coil11, magnetic poles being formed in the pair of pole cores12by the magnetic flux generated by the rotor coil11.

Each of the pole cores12is made of iron, a plurality of claw-shaped magnetic poles13having a tapered shape being formed at a uniform angular pitch in a circumferential direction on an outer circumferential edge portion of a cylindrical base portion14such that a direction of taper of each of the claw-shaped magnetic poles13is aligned in an axial direction. The pair of pole cores12are fixed to a shaft (not shown) facing each other such that the claw-shaped magnetic poles13intermesh with each other with end surfaces of the base portions14placed in contact with each other. Moreover, although not shown, shaft insertion apertures are disposed through the base portions14at central axial positions.

A bobbin16, as shown inFIG. 2, is prepared by shaping in a metal mold a material in which glass fiber is added to a thermoplastic resin such as nylon66, etc., and is constructed into an annular body having an angular C-shaped cross section in which first and second flange portions18and19are disposed so as to extend radially outward from two axial end portions of a drum portion17. Strengthening ribs20are formed by increasing a wall thickness of the first and second flange portions18and19. In this case, the ribs20are formed on the first and second flange portions18and19at six positions at a uniform angular pitch in a circumferential direction. Electrically-insulating tongue segments18aand19aare disposed on outer circumferential edges of the first and second flange portions18and19at a uniform angular pitch in a circumferential direction, the tongue segments18aand19abeing bent so as to lie alongside inner circumferential wall surfaces of the claw-shaped magnetic poles13when the bobbin16is mounted to the pair of pole cores12to prevent direct contact between the rotor coil11and the claw-shaped magnetic poles13. In addition, a pair of retaining portions21aand21bare disposed upright on outer circumferential edges of the first flange portion18, and a groove22described below is recessed into an inner peripheral wall surface of the first flange portion18so as to extend from an outer circumferential edge of the first flange portion18in the vicinity of the securing portion21ato the drum portion17.

This bobbin16is housed inside a space formed by the claw-shaped magnetic poles13and the base portions14of the pair of pole cores12by mounting the drum portion17to the base portions14so as to be held between root portions13aof the claw-shaped magnetic poles13from two sides (left and right inFIG. 1). The rotor coil11is constructed by winding a coil wire15into multiple layers on an outer circumference of the drum portion17so as to make the columns in each of the layers equal in number in an axial direction. Here, the coil wire15is wound into four layers of seven columns.

A method for installing the rotor coil11will now be explained.

The coil wire15is manufactured by coating an electrically-insulating coating such as a polyimide resin, etc., onto a surface of a core material such as copper, etc., having a circular cross section. This coil wire15is paid out through a nozzle23, a leading end thereof is wound onto a securing portion21aof the bobbin16, which is mounted to a spindle (not shown), and the coil wire15is led to the drum portion17through the groove22.

As shown inFIG. 4, the coil wire15is wound onto the drum portion17by rotating the bobbin16while paying the coil wire15out through the nozzle23. Here, the nozzle23is moved in the axial direction of the bobbin16as a first layer of the coil wire15is wound onto the drum portion17. The coil wire15in this first layer, as shown inFIG. 5, extends outward from the groove22onto the drum portion17, then makes approximately one turn around the drum portion17while contacting the inner peripheral wall surface of the first flange portion18, is then shifted toward the second flange portion19by one diameter of the coil wire15and makes approximately one turn around the drum portion17while contacting the first turn of the coil wire15, making a total of seven turns around the drum portion17in a similar manner. Here, a gap S is formed between the seventh turn of the coil wire15in the first layer and the inner peripheral wall surface of the second flange portion19.

Next, a second layer of the coil wire15is wound on top of the coil wire15in the first layer. First, the coil wire15, as shown inFIG. 6, is raised onto the seventh turn of the coil wire15, and makes approximately one turn in contact with the inner peripheral wall surface of the second flange portion19. Then, as shown inFIG. 7, the coil wire15is shifted toward the first flange portion18by one diameter of the coil wire15and makes approximately one turn around the drum portion17while contacting the first turn in the second layer of the coil wire15and contacting the sixth turn and the seventh turn in the first layer of the coil wire15, making a total of seven turns around the drum portion17in a similar manner.

This process of winding the coil wire15is performed repeatedly, and the coil wire15is wound onto the drum portion17to a height equivalent to a height of the root portion13aof the claw-shaped magnetic poles13to construct a coil field A. In Embodiment 1, the coil field A is constructed by winding the coil wire15into seven columns and four layers. Then, the coil wire15projecting out of the nozzle23is cut, and the cut end of the coil wire15is wound onto a securing portion21bto obtain the rotor coil11shown inFIG. 3.

In the rotor coil11prepared in this manner, as shown inFIG. 1, the coil wire15is installed on the drum portion17of the bobbin16in four layers of seven columns. In odd numbered layers, the coil wire15is wound such that the first turn is wound in contact with the inner peripheral wall surface of the first flange portion18, then a total of seven turns are made so as to contact each other, and there is a gap S between the seventh turn of the coil wire15and the inner peripheral wall surface of the second flange portion19. In even numbered layers, on the other hand, the coil wire15is wound such that the first turn is wound in contact with the inner peripheral wall surface of the second flange portion19, then a total of seven turns are made so as to contact each other, and there is a gap S between the seventh turn of the coil wire15and the inner peripheral wall surface of the first flange portion18. Because the first turn of the coil wire15in the second layer, for example, is wound in contact with the inner peripheral wall surface of the second flange portion19, the first turn of the coil wire15in the second layer presses the seventh turn of the coil wire15in the first layer toward the first flange portion18and acts to place the seven turns of the coil wire15in the first layer in close contact with each other. Thus, a state of close contact of the coil wire15wound into the first layer is ensured even if the coil wire15is wound sequentially into a second turn and a third turn in the second layer. Moreover, the state of close contact of the coil wire15wound into the lower layers is also similarly ensured when the coil wire15is wound into the third layer and the fourth layer. In other words, an aligned state of the coil wire15in each of the layers of the coil field A is ensured.

Thus, because the coil field A of the rotor coil11is constructed so as to make the columns in each of the layers equal in number, and in the odd numbered layers, the coil wire15contacts the inner peripheral wall surface of the first flange portion18, has a gap S relative to the inner peripheral wall surface of the second flange portion19, and is arranged in seven columns at an array pitch P (=D) from the first flange portion18toward the second flange portion19so as to be in contact with each other, and in the even numbered layers, the coil wire15contacts the inner peripheral wall surface of the second flange portion19, has a gap S relative to the inner peripheral wall surface of the first flange portion18, and is arranged in seven columns at an array pitch P (=D) from the second flange portion19toward the first flange portion18so as to be in contact with each other, the outside diameter of the coil field A does not become uneven relative to the axial direction of the bobbin16. As a result, when the rotor10is prepared with the rotor coil11mounted to the pole core12, the occurrence of damage to the electrically-insulating coating of the coil wire15resulting from the coil wire15positioned at the outermost radial portions of the coil field A coming into contact with inner circumferential wall surfaces of the claw-shaped magnetic poles13can be suppressed, enabling electrical insulation to be improved. Furthermore, deterioration in the balance of the load acting on the coil wire15can also be suppressed, preventing the coil field A from collapsing after completion of winding, etc.

Because the bobbin16is prepared by shaping in a metal mold a material in which glass fiber is added to a thermoplastic resin such as nylon66etc., the strength of the bobbin16is increased, suppressing the likelihood that the first and second flange portions18and19will be pushed by the coil wire15and collapse outward in the process of winding the coil wire15. In addition, because the ribs20are formed on the first and second flange portions18and19, the strength of the bobbin16is further increased, reliably preventing the outward collapse of the first and second flange portions18and19.

Moreover, outward collapse of the first and second flange portions18and19would bring about expansion of the gap S, giving rise to winding disturbances while winding the coil wire15, and the coil wire15would no longer be wound in an aligned state. As a result, the outside diameter of the coil field A would become irregular in an axial direction, making the balance of the load acting on the coil wire15deteriorate.

Next, the gap S will be explained with reference toFIGS. 8 to 10. FromFIGS. 8 to 10, it can be seen that a height from the drum portion17at a point of contact between the first turn of the coil wire15in the second layer and the seventh turn of the coil wire15in the first layer is reduced as the gap S increases.

InFIG. 9, a winding construction is shown in which each of the layers of the coil field A is constructed such that the coil wire15is arranged in seven columns at an array pitch P (=D) and the gap S between the seventh turn of the coil wire15and the first flange portion18(or the second flange portion19) is D/2. In this winding construction, the coil wire15in intermediate turns (excluding the first turn and the last turn) in intermediate layers (excluding the first layer and the uppermost layer) contacts six turns of coil wire15in a circumferential direction. In other words, the outer circumferential surface of the coil wire15is in contact with adjacent turns of coil wire15at six points having a uniform angular pitch, and is wound in an extremely stable state with good balance of the load acting on each of the turns of coil wire15. Furthermore, because the coil wire15in the first turn in each of the layers contacts the first flange portion18or the second flange portion19, when the coil wire15is wound into the first turn in the second layer, for example, the coil wire15wound in the first layer is pressed toward the first flange portion18, but this pressure is received by the first flange portion18through the first turn of the coil wire15, and the aligned state of the coil wire15in the first layer will not collapse. Thus, because the coil wire15can be wound into a stable state, the occurrence of winding disturbances in the winding process is reliably suppressed, enabling the coil wire15to be wound into an aligned state. As a result, a coil field A in which the outside diameter is uniform in an axial direction can be prepared simply, and a coil field A in which collapse is unlikely to occur is able to be achieved. Furthermore, because the coil wire15can be wound into the winding space of the bobbin16without waste, the number of winds of the coil wire15can be increased. In addition, because the coil wire15contacts six adjacent turns of coil wire15in a circumferential direction, heat generated in the coil wire15when the rotor coil11is energized is diffused through the adjacent turns of coil wire15to the surrounding area, improving the heat dissipation characteristics of the rotor coil11, thereby suppressing temperature increases in the rotor coil11.

InFIG. 8, a winding construction is shown in which each of the layers of the coil field A is constructed such that the coil wire15is arranged in seven columns at an array pitch P (=D) and the gap S between the seventh turn in the first layer of the coil wire15and the first flange portion18is greater than D/2 (S>D/2). In this winding construction, because the gap S is greater than D/2, the height of the first turn of coil wire15in the second layer from the drum portion17is lower than other turns of the coil wire15in the second layer, and the first turn is separated from the second turn of coil wire15. As the layer number increases, the number of turns of coil wire15with reduced height in the same layer increases. As a result, as indicated by the oblique lines inFIG. 8, winding disturbances arise partway through the process of winding the coil wire15, exacerbating irregularities in the outside diameter of the coil field relative to the axial direction of the bobbin16and also increasing deterioration in the balance of the load acting on the coil wire15. For example, the coil wire15wound into the first turn in the third layer presses the seventh turn of the coil wire15in the second layer toward the second flange portion19. Here, because the first turn and the second turn of the coil wire15in the second layer separates and the first turn of the coil wire15in the second layer is positioned below the second turn of the coil wire15in the second layer, the force pressing the seventh turn of the coil wire15in the second layer toward the second flange portion19cannot be received by the second flange portion19through the first turn of the coil wire15in the second layer. Thus, the seventh turn of coil wire15in the second layer is moved beyond the second turn of the coil wire15in the first layer due to that pressure, making it impossible to wind the coil wire15into an aligned state. In addition, in a vicinity of the portion in which winding disturbances occur, contact positions in a circumferential direction of the coil wire15are reduced in number compared to the winding construction shown inFIG. 9above. Thus, heat generated in the coil wire15when the rotor coil11is energized is less likely to be diffused through the adjacent turns of coil wire15to the surrounding area, thereby degrading the heat dissipation characteristics of the rotor coil11and giving rise temperature increases in the rotor coil11.

InFIG. 10, a winding construction is shown in which each of the layers of the coil field A is constructed such that the coil wire15is arranged in seven columns at an array pitch P (=D) and the gap S between the seventh turn of the coil wire15and the first flange portion18(or the second flange portion19) is less than D/4 (S<D/4). In this winding construction, because the gap S is less than D/4, the coil wire15in each of the layers contacts the coil wire15in the lower layer in a vicinity of apex portions. As a result, the number of layers in the coil field A is reduced, and the number of winds of coil wire15decreases, reducing the magnetomotive force generated by the rotor coil11. Furthermore, the coil wire15can be moved over the coil wire15in the lower layers with a small force, increasing the danger of the occurrence of winding disturbances partway through the process of winding the coil wire15, and also increasing the danger of the occurrence of collapse of the coil field A. In addition, because the coil wire15in the intermediate turns of the intermediate layers contacts only four adjacent turns of coil wire15in a circumferential direction, heat generated in the coil wire15when the rotor coil11is energized is less likely to be diffused through the adjacent turns of coil wire15to the surrounding area, thereby degrading the heat dissipation characteristics of the rotor coil11and giving rise temperature increases in the rotor coil11.

Thus, it is desirable for the gap S to be set to greater than or equal to D/4 and less than or equal to D/2.

Particularly if the gap S is set to D/2, because the coil wire15can be wound into a stable state, the occurrence of winding disturbances in the winding process is suppressed, enabling the coil wire15to be wound into an aligned state. As a result, a coil field A in which the outside diameter is uniform in an axial direction can be prepared simply, and a coil field A in which collapse is unlikely to occur is able to be achieved. In addition, the number of winds of coil wire15is increased, enabling the magnetomotive force generated by the rotor coil11to be increased.

FIG. 11is a cross section showing a rotor coil installed in a rotor for a rotary electric machine according to Embodiment 2 of the present invention. Moreover,FIG. 11is a longitudinal section passing through a crossover point C arising when a coil wire15is wound into a fourth layer.

In Embodiment 2, a coil field A of a rotor coil11, as shown inFIG. 11, is constructed such that a coil wire15is installed on a drum portion17of a bobbin16in four layers of seven columns, and crossover points C do not overlap in a radial direction.

In odd numbered layers of the coil field A, the coil wire15is wound such that a first turn is wound in contact with the inner peripheral wall surface of the first flange portion18, then a total of seven turns are made at an array pitch P (=D) so as to contact each other, and there is a gap S (=D/2) between the seventh turn of the coil wire15and the inner peripheral wall surface of the second flange portion19. In even numbered layers of the coil field A, on the other hand, the coil wire15is wound such that the first turn is wound in contact with the inner peripheral wall surface of the second flange portion19, then a total of seven turns are made at an array pitch P (=D) so as to contact each other, and there is a gap S (=D/2) between the seventh turn of the coil wire15and the inner peripheral wall surface of the first flange portion18. Shift starting positions at which the coil wire15is shifted by the array pitch P in an axial direction are offset in a circumferential direction for each of the layers. In other words, crossover points C arising when the coil wire15is wound into the second layer, the third layer, and the fourth layer are distributed in a circumferential direction, and do not overlap each other in a radial direction.

Moreover, when the coil wire15is wound into each of the layers (except for the first layer), as the coil wire15is shifted in an axial direction by the array pitch P from an n1th turn and wound into an (n1+1)th turn, it crosses over an apex portion of the coil wire15in the lower layer. These crossover points C are points where a coil wire15crosses over the apex portion of the coil wire15in a lower layer.

In a rotor coil, if the coil field A is constructed so that the crossover points C overlap in a radial direction, the outside diameter of the coil field A in the portion where the crossover points C overlap increases. The larger the amount of overlap at the crossover points C, the greater the outside diameter of the coil field A in the portion where the crossover points C overlap becomes. As a result, when a rotor is prepared with the rotor coil mounted to a pole core12, the electrically-insulating coating of the coil wire15may be damaged by the coil wire15positioned at the outermost radial portions of the coil field A where the crossover points C overlap coming into contact with the inner circumferential wall surfaces of the claw-shaped magnetic poles13. Furthermore, to avoid contact between the coil wire15positioned at the outermost radial portion of the coil field A and the inner circumferential wall surface of the claw-shaped magnetic poles13in the portion where the crossover points C overlap, it may be necessary to reduce the number of layers in the coil field A, decreasing the number of winds of coil wire15.

However, in Embodiment 2, because the crossover points C do not overlap in a radial direction, the crossover points C, which increase the outside diameter of the coil field A are distributed in a circumferential direction, thereby providing a coil field A having a uniform outside diameter. As a result, because the number of layers in the coil field A able to avoid contact between the coil wire15and the inner circumferential wall surfaces of the claw-shaped magnetic poles13can be increased, the occurrence of damage to the electrically-insulating coating of the coil wire15is suppressed, and a rotary electric machine having an increased number of winds of coil wire15can be obtained.

Moreover, inFIG. 11, the crossover points C arising when the coil wire15is wound into the fourth layer overlap in an axial direction, but overlapping of the crossover points C in an axial direction does not contribute to any increase in the outside diameter of the coil field A.

FIG. 12is a plan showing part of a bobbin in a rotary electric machine according to Embodiment 3 of the present invention, andFIG. 13is a cross section explaining an installed state of a rotor coil in the rotary electric machine according to Embodiment 3 of the present invention.

In Embodiment 3, as shown inFIG. 12, ridge portions25amaking approximately one turn around a drum portion17A of a bobbin16A are disposed at an array pitch of (D+G) in an axial direction on an outer circumferential wall surface of the drum portion17A. Thus, six guiding grooves25partitioned by the ridge portions15afor guiding coil wire are disposed side by side in an axial direction at an array pitch of (D+G) on the drum portion17A. An internal shape of each of the guiding grooves25is formed so as to be equivalent to an external shape of the coil wire15. Each of the ridge portions25ais purposely not formed over a predetermined circumferential range of the drum portion17A so that adjacent guiding grooves25communicate with each other. A securing portion21ais positioned radially outside the region where the ridge portions25aare not formed. Here, G is a gap between the coil wire15wound into each of the layers. Moreover, the bobbin16A is constructed in a similar manner to the bobbin16in Embodiment 1 above except for the fact that the guiding grooves25are formed on the drum portion17A.

Next, a winding construction of the rotor coil according to Embodiment 3 will be explained with reference toFIG. 13.

First, the coil wire15extends outward from the groove22onto the drum portion17A, is then led inside the first guiding groove25, and makes approximately one turn around the drum portion17A while contacting the inner peripheral wall surface of the first flange portion18. Next, the coil wire15is shifted toward the second flange portion19by (D+G) in the region where the ridge portions25aare not formed, is led inside the second guiding groove25, and makes approximately one turn around the drum portion17. The coil wire15makes a total of six turns around the drum portion17A in a similar manner. Here, the coil wire15is arranged at an array pitch P (=D+G), and a gap S (=(D+G)/2) is formed between the sixth turn of the coil wire15and the inner peripheral wall surface of the second flange portion19.

Next, a second layer of the coil wire15is wound on the coil wire15in the first layer. First, the coil wire15is raised onto the sixth turn of the coil wire15in the first layer, and makes approximately one turn in contact with the inner peripheral wall surface of the second flange portion19. Then, the coil wire15is shifted toward the first flange portion18by (D+G) and makes approximately one turn around the drum portion17A while contacting the sixth turn and the fifth turn of the coil wire15in the first layer, making a total of six turns around the drum portion17A in a similar manner. Here, the coil wire15is arranged at an array pitch P (=D+G), and a gap S (=(D+G)/2) is formed between the sixth turn of the coil wire15and the inner peripheral wall surface of the first flange portion18.

This process of winding the coil wire15is performed repeatedly, and the coil wire15is wound onto the drum portion17A to a height equivalent to a height of the root portion13aof the claw-shaped magnetic poles13to construct a coil field A.

In the coil field A of a rotor coil prepared in this manner, as shown inFIG. 13, in odd numbered layers, the coil wire15is wound such that a first turn is wound in contact with the inner peripheral wall surface of the first flange portion18, then a total of six turns are made at an array pitch P (=D+G), and there is a gap S (=((D+G)/2) between the sixth turn of the coil wire15and the inner peripheral wall surface of the second flange portion19, and in even numbered layers, the coil wire15is wound such that the first turn is wound in contact with the inner peripheral wall surface of the second flange portion19, then a total of six turns are made at an array pitch P (=D+G), and there is a gap S (=(D+G)/2) between the sixth turn of the coil wire15and the inner peripheral wall surface of the first flange portion18. In each of the layers, the coil wire15is arranged so as to have a gap G.

According to Embodiment 3, because the coil wire15in the first layer (the lowest layer) is wound onto the drum portion17A so as to be housed inside guiding grooves25having an internal shape equivalent to an external shape of the coil wire15, movement of the coil wire15in an axial direction is prevented by the guiding grooves25, maintaining an aligned state. Furthermore, because the coil wire15in each of the layers is arranged at an array pitch P (=D+G), and in the odd numbered layers, the first turn of the coil wire15contacts the inner peripheral wall surface of the first flange portion18, and the sixth turn (the final turn) of the coil wire15is separated from the inner peripheral wall surface of the second flange portion19by a gap S (=(D+G)/2), and in the even numbered layers, the first turn of the coil wire15contacts the inner peripheral wall surface of the second flange portion19, and the sixth turn (the final turn) of the coil wire15is separated from the inner peripheral wall surface of the first flange portion18by a gap S (=(D+G)/2), the coil wire15in each of the layers is positioned at a uniform height from the drum portion17A, and each of the intermediate turns of coil wire15in the intermediate layers contact four turns of coil wire15in upper and lower layers in a symmetrical positional relationship relative to a line passing through a central axis of the coil wire15and a central axis of the drum portion17A in a cross section through the central axis of the coil wire15, improving the balance of the load acting on each of the turns of coil wire15. Thus, the coil wire15can be wound onto the drum portion17A in a stable state without winding disturbances arising. As a result, a coil field A in which the outside diameter is uniform in an axial direction can be prepared simply, and a coil field A in which collapse is unlikely to occur is able to be achieved. In addition, because the coil wire15can be wound into the winding space of the bobbin16without waste, the number of winds of the coil wire15can be increased.

Here, when consideration is given to irregularities in coil wire diameter due to irregularities in coil wire tension from a coil winding machine, it is desirable for the array pitch P of the guiding grooves25to be set to 1 to 1.04 times (1≦P≦1.04 D) the diameter of the coil wire.

Moreover, it goes without saying that guiding grooves25according to Embodiment 3 may also be applied to the rotors of Embodiments 1 and 2 above. In that case, the array pitch of the guiding grooves25is D.

FIG. 14is a side elevation showing a bobbin used in a rotor for a rotary electric machine according to Embodiment 4 of the present invention, andFIG. 15is a cross section taken along line XV—XV inFIG. 14viewed from the direction of the arrows.

A drum portion17B of a bobbin16B in Embodiment 4 is constituted by: a large radius portion26having a radius r1; a small radius portion27having a radius r2(<r1); and a linking portion28extending tangentially to the small radius portion27and connecting smoothly with the large radius portion26. Guiding grooves25are formed in the outer circumferential wall surface of the large radius portion26, but the guiding grooves25are not formed in the small radius portion27. The small radius portion27is formed over a 60-degree range relative to a circumferential direction of the drum portion17B, and a securing portion21ais positioned radially outside within the region where the small radius portion27is formed. In addition, although not shown, crossover points C in each of the layers of a coil field are formed in a region radially outside the small radius portion27in a similar manner to Embodiment 2 above so as not to overlap each other in a radial direction. Moreover, the rest of this embodiment is constructed in a similar manner to Embodiment 3 above.

According to Embodiment 4, because the crossover points C in each of the layers of the coil field are formed in a region radially outside the small radius portion27, the increase in the outside diameter of the coil field accompanying formation of the crossover points C is canceled out by the small radius portion27of the drum portion17B, making the outside diameter of the coil field generally uniform. As a result, because the number of layers in the coil field able to avoid contact between the coil wire15and the inner circumferential wall surfaces of the claw-shaped magnetic poles13can be increased, the occurrence of damage to the electrically-insulating coating of the coil wire15is suppressed, and a rotary electric machine having an increased number of winds of coil wire15can be obtained.

Generally, if the inside diameter of the drum portion16B is kept constant, the radius r2of the small radius portion27cannot be reduced very much. If the increase in the outside diameter of the coil field accompanying formation of the crossover points C is large, it is necessary for (r1–r2) to be increased in order to cancel out the increase in the outside diameter thereof. Thus, an (r1–r2) capable of canceling out the increase in the outside diameter of the coil field accompanying formation of the crossover points C must be achieved by increasing the radius r1of the large radius portion26. However, increasing the radius r1of the large radius portion26without changing the size of the pole core12, leads to a reduction in the winding space for the coil wire15, thereby reducing the magnetomotive force of the rotor coil.

However, in Embodiment 4, because the crossover points C in each of the layers of the coil field are distributed circumferentially in a region radially outside the small radius portion27, the increase in the outside diameter of the coil field accompanying formation of the crossover points C is reduced. Thus, because it is not necessary to reduce the radius r2of the small radius portion27very much, the increase in the outside diameter of the coil field accompanying formation of the crossover points C can be canceled out without increasing the radius of the large radius portion26. As a result, winding space for the coil wire15is ensured, suppressing reductions in the magnetomotive force of the rotor coil.

A circumferential range θ in which the small radius portion27is formed will now be explained.

If the circumferential range θ is reduced, the range over which the crossover points C are distributed in a circumferential direction is also reduced. If the circumferential range θ is less than 40 degrees, the crossover points C are concentrated in a narrow circumferential range, making the circumferential distance between the crossover points C extremely short. Thus, even if the crossover points C do not overlap in a radial direction, the increase in the outside diameter of the coil field accompanying formation of the crossover points C in upper layers is increased significantly due to the influence of the crossover points C positioned in lower layers.

If the circumferential range θ is too large, the region where the guiding grooves25are not formed becomes large. Axial movement of the coil wire15wound into the first layer (the lowest layer) ceases to be regulated in a range exceeding 80 degrees in a circumferential direction, and when the coil wire15is wound into the second layer, the coil wire15in the first layer positioned in the region where the guiding grooves25are not formed may move in an axial direction, giving rise to winding disturbances.

Thus, if the circumferential range θ is set to greater than or equal to 40 degrees and less than or equal to 80 degrees, preferably to 60 degrees, the increase in the outside diameter of the coil field resulting from the crossover points C can be suppressed, and the occurrence of winding disturbances during the process of winding the coil wire15can also be suppressed.

FIG. 16is a cross section showing part of a rotor for a rotary electric machine according to Embodiment 5 of the present invention.

In Embodiment 5, as shown inFIG. 16, a coil field A is constructed by winding a coil wire15onto a bobbin16in seven columns and four layers, and then a coil field peaked winding portion29is constructed by further winding one layer of four columns and winding one turn on top of that. Moreover, the rest of this embodiment is constructed in a similar manner to Embodiment 1 above.

In a rotor10A according to Embodiment 5, because a coil field peaked winding portion29is formed on an upper portion of the coil field A by winding a coil wire15into four columns and winding one turn on top of that, the number of winds of coil wire15can be increased using clear space between the coil field A and the claw-shaped magnetic poles13of the pole core12. Thus, the magnetomotive force of the rotor coil is increased, enabling output of the rotary electric machine to be improved.

Because the coil field peaked winding portion29is constituted by a smaller number of columns than the number of columns in each of the layers of the coil field A, it can be disposed in the clear space between the coil field A and the claw-shaped magnetic poles13of the pole core12while still avoiding contact with the claw-shaped magnetic poles13.

Here, the coil field peaked winding portion29need only be constituted by a plurality of layers with a smaller number of columns than the number of columns in each of the layers of the coil field A. It is desirable for the number of columns in each of the layers of the coil field peaked winding portion29to decrease gradually in an upward direction to match the shape of the clear space between the coil field A and the claw-shaped magnetic poles13of the pole core12.

Moreover, the rotor according to the present invention can be applied, for example, to a rotary electric machine such as an alternator, an alternating-current motor, an alternating current electric generator-motor, etc., mounted to an automotive vehicle such as a passenger car, a truck, an electric train, etc.

Furthermore, in Embodiments 3 and 4 above, axial movement of the coil wire15wound into the first layer (the lowest layer) is regulated by providing guiding grooves25, but the means for regulating the axial movement of the coil wire15is not limited to the guiding grooves25and, for example, an adhesive material, a bonding agent, etc., may also be formed on the outer circumferential surface of the drum portion in a process preceding the winding of the coil wire15.

In each of the above embodiments, the coil field A is formed into four layers of seven columns or four layers of six columns to facilitate explanation, but the number of columns and the number of layers in the coil field A is not limited thereto.

INDUSTRIAL APPLICABILITY

As explained above, in a rotor according to the present invention, because a coil field of a rotor coil is constructed so as to have a uniform outside diameter by winding a coil wire into an aligned state, the coil field can be constructed to a high density and be less likely to collapse while avoiding contact between claw-shaped magnetic poles and the coil wire, making it useful as a rotor for the rotary electric machine such as an automotive alternator, etc., for mounting to an automotive vehicle such as an automobile, etc.