JP2770482B2 - Electric motor - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an outer rotor type electric motor, and more particularly, to a means for inserting a lead wire.

[Prior Art] FIG. 4 shows an outer rotor type brushless motor as a conventional example. That is, the motor includes a fixed shaft 2 erected on a base 1. A stator core 3 having a stator winding 3a is attached to the fixed shaft 2. A substantially cylindrical rotor 4 is coaxially fitted to the fixed shaft 2 via, for example, a pair of upper and lower bearings 5 and 6. The stator core 3 is provided on the inner peripheral surface of the rotor 4.
Are provided. Further, sealing means 8, 8 for holding a magnetic fluid as a sealing material are disposed at two places, an upper part and a lower part of the stator 4. The sealing means 8 is formed, for example, by holding a magnet 8b between a pair of donut-shaped pole pieces 8a, 8a. With this structure, in this type of motor, the lead wire 9 of the stator winding 3a is drawn out of the base 1 through an insertion hole 10 formed in the fixed shaft 2. In this case, three lead wires 9 are passed through one insertion hole 10, and as the lead wire 9, the winding end of the stator winding 3a covered with an insulating tube is used. In the case of a motor for a hard disk drive or the like in which the inside of the rotor 4 is sealed by the sealing means 8 and 8 and the periphery of the rotor 4 is covered with a sealed case (not shown) as described above, a fixed shaft 2 is additionally provided with a ventilation hole 11 for communicating the internal space of the rotor 4 with the outside of the base 1.

[Problem to be Solved by the Invention] However, since the insertion hole 10 in the above-described conventional example is bent as shown in the drawing, that is, the first through hole 10 which is shortly formed in a direction substantially orthogonal to the axis of the fixed shaft 2 is provided. Hole 10a
And a second hole 10b drilled substantially parallel to the axis of the fixed shaft 2 from the end thereof, so that it is difficult to insert the lead wire 9, and the lead wire 9 is inserted into the bent insertion hole 10. In order to insert the lead wire, a lead wire with an insulating tube covering the winding end of the stator winding 3a or a member that flexibly follows the bending of the lead wire hole must be used. In addition, there is a limitation in selecting members. In particular, in the case of a three-phase star connection, each of the three winding ends is covered with an insulating tube, and is then inserted one by one or together. In addition, it is time-consuming and unsuitable for mass production, and is extremely difficult to automate.

In addition, even when drilling, the first hole 10a and the second hole 1
0b must be processed separately, which is troublesome twice, and burrs that damage the insulating tube are likely to occur at the intersections, making it difficult to process. Therefore, when processing parts, labor, time, and accuracy are reduced. There was a problem in parts processing and assembly such as necessity.

"Means for Solving the Problems" In order to solve the above problems, in the present invention, there is provided a stator core having a stator core including a stator winding, and a fixed shaft erected on a base; And a cylindrical rotor coaxially fitted around the fixed shaft via a predetermined bearing means, and a lead wire of the stator winding is connected to the fixed shaft. In the electric motor drawn out of the base through the insertion hole formed in the base, the base side portion including the portion where the stator core of the fixed shaft is attached is more than the counter base side portion. It is a large-diameter portion, and the insertion hole is drilled from the step surface in parallel with the axis of the fixed shaft.

[Operation] According to the above configuration, the insertion hole can be formed straight. Therefore, insertion of the lead wire is easy, and
The member itself as the lead wire itself can be selected in a relatively wide range without being restricted by the insertion workability, and furthermore, the drilling process only needs to be done once, there is no intersection between holes, no burr occurs, Accuracy is not so necessary for processing.

Hereinafter, an embodiment of the present invention will be described in detail with reference to FIG. In this figure, the same reference numerals are given to portions which are the same as or are regarded as the same as those in FIG. 4 described above.

In this electric motor, the base 1 side portion including the portion where the stator core 3 of the fixed shaft 2 is mounted has a larger diameter than the opposite base 1 side portion. That is, a portion from the mounting portion of the stator core 3 to the end on the side of the base 1 is defined as a large diameter portion 2a, and an insertion hole 10 'and a ventilation hole are formed from the upper step surface 2b in parallel with the axis of the fixed shaft 2. 11 'is drilled straight.

In this embodiment, a three-phase star connection and three lead wires are provided, so that three insertion holes 10 'are provided, and the three insertion holes 10' are provided with the windings of the stator winding 3a. The ends of which are covered with an insulating tube and each of which has a lead wire 9 are inserted, respectively. However, one through hole 10 ′ may be provided, and three lead wires 9 may be collectively inserted therethrough.

In this manner, the lead wire 9 is inserted through the insertion hole 10 '. The lead wire 9 preferably has a relatively hard resin insulating film 12b as shown in FIGS. 2 and 3. In this embodiment, three conductive pins 12a are integrally connected by a spacer ring 13 at the upper end thereof. The spacer ring 13 is provided with a ventilation hole 13 'continuous with the ventilation hole 11'.

At the time of assembling, for example, the stator core 3 including the stator winding 3a is fitted to the fixed shaft 2, and then the lead wire 9 is connected to the stator core 3
Through the insertion hole 9 from above. Then, the upper end of the conductive pin 12a as a lead wire is connected to the winding end of the stator winding 3a, and the lower end is connected to a predetermined portion of a control board (printed board) 14 provided on the base 1. Unlike the above assembly, the conductive pins 12a are fixed to the stator core 3 first,
After that, the stator pin 3 may be fitted into the fixed shaft 2 and the conductive pin 12a may be inserted into the insertion hole 10 'at the same time. In this case, if positioning means is provided in advance between the conductive pin 12a and the stator core 3, when the fixed shaft 2 is assembled, the fixed shaft 2 and the stator are inserted through the insertion hole 10 'and the conductive pin 12a. The core 3 can be positioned. In either method, the connection between one end of the conductive pin 12a and the end line of the stator winding 3a can be performed on the wide side of the working space.

[Effect of the Invention] As described above, according to the present invention, the base side portion including the portion where the stator core 3 of the fixed shaft is mounted has a larger diameter portion than the opposite base side portion, and the insertion hole is formed. Is formed in parallel with the axis of the fixed shaft from the step surface, so that the operation of inserting the lead wire is easy in assembling, and the material of the lead wire is not restricted, and automation is possible. In addition, there is a merit that, in the processing of parts, drilling of the insertion hole is completed at once, no burr is generated in the insertion hole, and processing accuracy is not particularly required. Further, in the case of small-volume production, the one obtained by covering the end wire of the stator winding with an insulating tube as in the embodiment shown in FIG. 1 is used. In the case of mass production, the embodiment shown in FIG. As described above, a separately formed conductive pin can be used as a lead wire, and it can flexibly cope with any case. In particular, in the case of the embodiment shown in FIG. 2, positioning is possible, and there are many advantages such as no need for a separate positioning member, and the effect is remarkable.

[Brief description of the drawings]

1 and 2 are cross-sectional views showing an embodiment of the electric motor according to the present invention, FIG. 3 is a perspective view showing a lead wire used in the embodiment of FIG. 2, and FIG. 4 is a conventional example. It is sectional drawing which showed. In the figure, 1 is a base, 2 is a fixed shaft, 3 is a stator core, 3a is a stator winding, 4 is a rotor, 5 and 6 are bearings, 7 is a driving magnet, 8 is sealing means, 9 Is the leader, 10,10 '
Are insertion holes, 11 and 11 'are ventilation holes, 12a is a conductive pin, 12b is an insulating coating, 13 is a spacer ring, and 14 is a control board.

Claims (3)

(57) [Claims] The present invention has a stator core including a stator winding, a fixed shaft erected on a base, and a drive magnet corresponding to the stator core. A cylindrical rotor fitted coaxially around the fixed shaft, and pulling out a lead wire of the stator winding to the outside of the base through an insertion hole formed in the fixed shaft. In the electric motor, the base portion including the portion where the stator core of the fixed shaft is mounted has a larger diameter portion than the opposite base portion, and the insertion hole is fixed from the step surface thereof. An electric motor characterized by being bored in equilibrium with the axis of a shaft. 2. The electric motor according to claim 1, wherein the number of the insertion holes is equal to the number of the lead wires. 3. The fixed hole according to claim 1, wherein a large diameter portion of the fixed shaft is provided with a ventilation hole communicating between the inside of the rotor and the outside of the base in parallel with the axis of the fixed shaft. Electric motor.