JP4734516B2 - DC brushless motor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a DC brushless motor mainly used in industrial precision instruments such as measuring devices, and more specifically, mounted on measuring instruments that require lightweight, compact, and highly efficient rotational operation. The present invention relates to an inner rotor magnet type DC brushless motor unit.
[0002]
[Prior art]
Conventionally, a DC brushless motor of an inner rotor magnet type has a magnetic material as a housing case for the exterior of a stator part or a laminated core in the case, and a field coil is disposed on the inner diameter of the case or on the inner side of the case. On the other hand, a configuration in which a cylindrical magnet having a rotating shaft shaft penetrating at the center position is used as a rotor portion is generally used.
[0003]
For example, as shown in FIG. 7, an inner rotor portion composed of a cylindrical magnet 4 and a shaft 3 penetrating the center thereof is arranged at the axial center position of the flange 2 positioned at both end openings of the cylindrical housing case 1, and the bearing 6 The rotor part is driven to rotate by a rotating magnetic field generated by commutation of the field coil 5 fixedly arranged on the inner peripheral surface of the magnetic housing case 1 serving as an opposing yoke. There is a brushless motor 110.
[0004]
[Problems to be solved by the invention]
However, in the case of the slotless type DC brushless motor 110 having no teeth as shown in FIG. 7, the portion serving as the opposing yoke compared to the total length of the magnet 4 in the axial direction, that is, the opposing yoke portion of the housing case 1 shown in FIG. Since the magnetic flux area increases and a larger torque output can be obtained when the length is longer, it has been customary to design the opposite yoke side longer in the conventional DC brushless motor.
[0005]
As a result, both the rotor magnet and the opposing yoke are extended in the axial direction, and the total length of the motor is also increased. Moreover, the difference in the influence on the motor characteristics due to the difference in the winding type of the field coil to be mounted (field winding 50 of the separate winding type is shown in FIG. 8) was slightly reduced by the dimensional expansion in the axial direction. In terms of weight, the rotor magnet and the opposing yoke increase in weight, and it is difficult to reduce the weight and size.
[0006]
The present invention solves the above-mentioned problems, and uses a turtle shell-shaped cylindrical field coil having a large number of axially linear portions of the winding shape as the field coil. Another object of the present invention is to provide a lightweight, compact and high-performance motor with good magnetic efficiency.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, in the inner rotor magnet type DC brushless motor according to claim 1, the rotor portion cylindrical magnet and the stator portion ring-shaped opposing yoke are formed of a turtle shell winding type cylindrical field coil. A gap as a drive system is arranged inside and outside the motor so as to oppose inside and outside, and in the vicinity of the central band width portion of the winding wound linearly in the axial direction of the field coil, the rotor magnet and The opposing yoke is formed and arranged with substantially the same axial length as the field coil band width portion, and the radial direction of the opposing yoke as the radial gap arrangement configuration forming the magnetic circuit The coil gap width part is fitted and the air gap dimension with the magnet is set narrowly.
[0008]
According to the present invention, even in an inner rotor magnet type DC brushless motor with a small outer diameter, the opposing yoke exists close to the bulge of the multiple winding portion in the both ends of the cylindrical coil, so that it faces the magnet. Since the gap between the yoke (air gap) can be made small, this structural arrangement improves the magnetic efficiency and calculates the axial length so as to obtain the required driving rotational torque. Simple basic design becomes possible.
[0009]
Further, in the inner rotor magnet type DC brushless motor according to a second aspect, in addition to the first aspect, the stator-facing yoke is mounted and arranged in an axial direction with respect to the rotor magnet. Is.
[0010]
According to the present invention, since one-way pre-pressure is generated on the axial thrust ring of the rotor portion in the inner rotor magnet type DC brushless motor, rattling of the rotor portion shaft during the stop state or during the rotation operation can be suppressed.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of a DC brushless motor structure according to the present invention will be described in detail with reference to the drawings.
The present invention is not limited to this embodiment, and the detailed structure is taken as an example.
[0012]
1 and 2 are examples of a side sectional view showing a configuration of an inner rotor magnet type DC brushless motor 100 according to an embodiment of the present invention. This structure has the same basic component structure as the conventional one, and the inner rotor part consisting of the cylindrical magnet 4 and the shaft 3 passing through the center of the cylindrical magnet is integrally molded with a cylindrical opposing yoke 11 (laminated core ring). A shaft 6 is rotatably supported by a bearing 6 at the axial center position of the flange 2 located at the side end opening of 9, and this is commutated and energized to the field coil 5 side fixedly arranged inside the opposing yoke by the resin integral mold. This is a DC brushless motor that rotationally drives the rotor using a rotating magnetic field that is electrically generated in the stator.
[0013]
In the case of this motor, the rotor cylindrical magnet 4 and the stator ring-shaped opposing yoke 11 have a gap as a drive system inside the motor with the turtle shell-molded cylindrical field coil 5 shown in FIGS. The rotor magnet 4 and the opposing yoke 11 are arranged in the vicinity of the central band width portion W of the winding that is wound inside and outside, and further wound linearly in parallel with the axial direction of the field coil 5. As shown in FIG. 2, the inner diameter side of the opposing yoke 11 is arranged on the inner diameter side of the opposing yoke 11 as a radial gap arrangement configuration which is formed and arranged with substantially the same axial length dimension as the field coil band width portion W. The air gap dimension G between the magnet coil 4 and the magnet 4 is set so as to be narrowly fitted to the step D of the magnetic coil band width portion W.
[0014]
As a result, even in the case of an inner rotor magnet type DC brushless motor with a small outer diameter, the opposing yoke approaches the effective winding portion of the axial straight line while avoiding the bulge of the hatched multiple winding portions in both ends of the cylindrical coil. Therefore, the gap (air gap dimension G) between the magnet and the opposing yoke can be narrowed. In addition, since the magnetic efficiency is improved by this structural arrangement, if a length dimension in the axial direction is calculated so as to obtain a driving torque as required, a short type and compact basic design becomes possible compared to the conventional case. In addition, the weight can be reduced. Further, it is easy to install a hall sensor (reference numeral 10 in FIG. 1) in the vicinity of the opposing yoke.
[0015]
FIG. 5 is a schematic side sectional view of the field coil 5. As shown in the figure, the winding portion where the band width portion W is obviously thinner in the radial direction than the overlapped portions on both sides is crossed. It can be seen that it is. For reference, as a general outline of the manufacturing process of the turtle shell-shaped field coil 5, the winding bundle wound around the hexagonal reel is removed from the reel, and the two parallel sides of the cylindrical hexagon are A so-called tortoiseshell-shaped cylindrical field that forms a cylindrical coil by collapsing in one direction of the shaft, folding it, press-molding it into a plate shape, and then rolling the molded winding strips to form a cylindrical coil It is a coil.
[0016]
By using this cylindrical field coil, the opposing yoke 11 is fitted into the concave portion of the band width portion W, avoiding the bulging portions of the multiple windings on both opening ends of the field coil 5, and FIG. As shown, the gap (air gap dimension G) between the magnet 4 and the opposing yoke 11 can be set narrow. Furthermore, because the magnet 4 and the opposing yoke 11 have the same axial length, the shaft 3 is partially restricted (thrust ring 12), but the thrust position is stabilized by the magnet's own magnetic attractive force. Determined.
[0017]
An example of this application is a structure as shown in FIG. This is a mounting arrangement in which the stator-facing yoke 11 is offset (symbol F) in the axial direction with respect to the rotor magnet 4, so that the entire rotor section is thrust in the thrust direction (arrow P) by magnetic attraction force. Thus, a pre-pressure can be generated, and rattling of the rotor portion (shaft 3) in a stopped state or during rotation can be suppressed.
[0018]
Although all the structures have been described with respect to the cylindrical DC brushless motor in the embodiments of the present invention, the structure of the motor details is not limited to this. In this embodiment, a small inner rotor magnet type DC brushless motor having an outer diameter of 15 mm or less has been described as an example. However, a motor having a similar structure in which the rotor portion (magnet or the like) has a heavy mass. Needless to say, the present invention can be applied to any other size motor.
[0019]
【The invention's effect】
As described above, according to the DC brushless motor according to the first aspect of the present invention, even in the case of the inner rotor magnet type DC brushless motor having a small outer diameter, diagonal multiplexing of both ends of the cylindrical coil of the turtle shell winding mold is performed. Since the opposing yoke exists close to the effective winding portion of the concave line while avoiding the bulge of the winding portion, the gap (air gap dimension G) between the magnet and the opposing yoke can be narrowly arranged. With this configuration, the magnetic efficiency is improved, so that it is possible to make a basic design of a DC brushless motor that is shorter and more compact and has a higher performance than before, while ensuring the axial length as required. In addition, the weight can be reduced.
[0020]
Furthermore, with this structure, it is possible to secure a space for installing the Hall sensor in the vicinity of the opposing yoke without changing the outer diameter of the motor, and the Hall sensor can be easily attached as necessary.
[0021]
According to the DC brushless motor of the present invention, the preload can be generated in one direction of the axial thrust ring of the rotor portion in the inner rotor magnet type DC brushless motor. The backlash of the rotor during operation can be suppressed, and a high-performance DC brushless motor with less vibration and noise can be realized.
[Brief description of the drawings]
FIG. 1 is a side sectional view showing an example of a DC brushless motor according to an embodiment of the present invention.
FIG. 2 is a side sectional view showing an internal configuration example of a DC brushless motor according to an embodiment of the present invention.
FIG. 3 is a perspective view showing a winding shape of a turtle shell winding mold field coil according to an embodiment of the present invention.
FIG. 4 is a side view showing a winding shape of a turtle shell winding mold field coil according to an embodiment of the present invention.
FIG. 5 is a schematic side sectional view showing a winding shape of a turtle shell-shaped field coil according to an embodiment of the present invention.
FIG. 6 is a side sectional view showing an example of the internal configuration of a DC brushless motor as another example according to the embodiment of the present invention.
FIG. 7 is a side sectional view showing a configuration of a conventional DC brushless motor.
FIG. 8 is a perspective view showing another winding shape example of a cylindrical field coil.
[Explanation of symbols]
1 Housing Case 2 Flange 3 Shaft 4 Magnet 5, 50 Field Coil 6 Bearing 7 FPC Feeding Section 7 'FPC Holding Plate 8 Tap Wire 9 Housing
10 Hall sensor
11 Opposite yoke
12 Thrust ring
100, 110 Inner rotor magnet type DC brushless motor

Claims (2)

In an inner rotor magnet type DC brushless motor, the rotor part cylindrical magnet and the stator part ring-shaped opposing yoke are opposed to each other inside and outside with a gap as a drive system inside the motor across the turtle shell winding type cylindrical field coil. Further, in the vicinity of the central band width portion of the winding wound linearly in the axial direction of the field coil, the rotor magnet and the opposing yoke have substantially the same axis as the field coil band width portion. As a radial gap arrangement configuration that forms and arranges in the length direction of the direction and forms a magnetic circuit, the inner diameter side of the opposing yoke is fitted to the step width of the field coil band, and the air gap dimension with the magnet is set to be narrow. DC brushless motor characterized by The DC brushless motor according to claim 1, wherein the stator portion opposing yoke has a mounting arrangement configuration that is offset in an axial direction with respect to the rotor magnet.

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