JP3904227B2 - Power supply mechanism for small motors - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a miniature motor having a very small diameter, such as an ultra-compact driving motor for a millimeter machine or a vibration motor for a wristwatch with a silent vibration alarm function, and more particularly to a power feeding mechanism of the motor.
[0002]
[Prior art]
Conventionally, the demand for small cylindrical motors with an outer diameter of around 5mm has been the demand for mobile communication devices such as pagers, PHS, and mobile phones as vibration motors with weights, or OA equipment, precision equipment, radio control models as drive motors for equipment parts. Have been put into practical use and have been put to practical use. In recent years, for example, it has been renewed as an ultra-compact motor mainly intended for mounting on precision medical equipment such as in utero diagnosis and treatment, or on micro / milli-machine high-tech industrial equipment such as self-propelled in-pipe environment confirmation devices. Demand for ultra-small diameters and miniaturization is increasing year by year.
[0003]
However, the smaller and smaller the motor, the more difficult it is to manufacture and assemble each part, as well as the configuration, dimensions, placement and installation of each part and the installation of power supply wiring from the power supply side at the design stage. The problem of space saving of the turning mechanism occurs. Especially in the case of ultra-small-diameter motors with an outer diameter of 3 mm or less, it is important to design a small-diameter design for the power supply wiring mechanism and where to place the best installation location to reduce the diameter and save space. It becomes a point.
[0004]
For this reason, in general, brushless motors that do not require a brush and commutator, which are structurally advantageous for the smallest diameter, are becoming the mainstream of the smallest motors, and at the same time, the energy efficiency of the motor For this reason, a brushless motor of a type having a permanent magnet type rotor and having a plurality of flat field coils on the circumference of a cylinder is used.
[0005]
An example of a conventional brushless motor having this permanent magnet type rotor is shown in FIGS. In FIG. 3, reference numeral 1 denotes a rotor having an output shaft 2 at one end, and is rotatable by two bearings 4 mounted at the center of both end shafts of the housing 7 via a bearing holder 6 and a substantially cylindrical body holder 15. It is supported by.
[0006]
5 is a rotating magnetic field in which at least three or more individual bobbinless coils formed by overlapping and winding self-bonding wires in a flat ring shape are arranged on the inner peripheral surface of the cylindrical housing 7 at equal angles in the circumferential direction. In the field coil unit for generating, the rotor 1 rotates following the rotating magnetic field formed by each field coil 5. Further, the flat field coil 5 can be inserted and fixed to the inner diameter of the cylindrical housing 7 while being bent and bonded and fixed along the outer peripheral surface of the substantially cylindrical holder 15 of FIG. A device has been devised to facilitate the assembly of a small motor.
[0007]
Further, 9 shown in FIG. 3 is a tap wire drawn out from the field coil 5 of the plurality of flat windings, and one end of a metal relay pin 16 attached to the end of the substantially cylindrical holder 15. The lead wire 17 connected to the drive circuit is connected to the other end side to form a conduction path of the power feeding mechanism. A thrust plate 3 attached to the rotor 1 is inserted to restrict a gap formed by the thrust plate 3 and the stator-side bearing 4 to limit the play in the thrust direction of the rotor 1. Is provided.
[0008]
In another example of the configuration of FIG. 4, three or more pieces are formed on one flexible substrate 18 on which circuit wiring is formed in order to facilitate the assembly of the stator coil portion by the same method as in FIG. 3. A field coil 5 using a flat-shaped bobbinless coil is mounted, and the cylindrical winding portion of the flexible substrate 18 is bent and inserted and fixed to the inner surface of the housing 7 along the inner wall surface. These bobbinless coils on the substrate are arranged at equal angles in the circumferential direction of the cylinder, and have a structure that forms a rotating magnetic field. The power supply wiring portion of the flexible substrate 18 is drawn out of the housing 7 through an opening 19 provided in the outer peripheral portion of the cylindrical housing of the housing 7 and connected to the drive circuit side in a state of protruding to the outer periphery of the housing. Has been.
[0009]
As described above, the power feeding mechanism of the small-diameter motor based on the conventional brushless motor represented by FIGS. 3 and 4 is easy in assembling work, the field coil tap wire 9 being assembled or in operation. In order to prevent disconnection to the rotor side of the field coil unit, which may be generated by using a plurality of flat winding coils as separate members for the field coil 5, the field coil 5 is a substantially cylindrical holder. Generally, it is generally fixed to one outer surface of a cylindrical structure such as the inner periphery of the flexible substrate 18 bent into a cylindrical shape, and then inserted and fixed to the inner diameter of the housing 7.
[0010]
[Problems to be solved by the invention]
However, in the above-described conventional structure, even if the field coil 5 has the same flat winding configuration and the rotor magnet specifications have the same performance, each design structure has a gap between the rotor 1 and the housing 7. In the case of the configuration of FIG. 3, the magnetic gap width increases by the amount of the substantially cylindrical holder 15 in the case of FIG. 3 and the flexible substrate 18 in the radial thickness dimension in the case of FIG. And the generated torque of the rotor 1 is reduced.
[0011]
Further, in the case of the structure shown in FIG. 4, when the flexible substrate 18 is taken out of the housing 7 through the opening 19, the protrusion convex portion is exposed at a part of the outer diameter of the housing 7 by the thickness of the flexible substrate 18. It had the disadvantage of increasing the outer diameter that the benefit of the smaller diameter would be impaired. Further, even in the case of using the lead wire 17 in FIG. 3, there is a soldering operation for the connection with the relay pin 16, the lead wire has a thin wire diameter, and there is a risk of poor conduction and disconnection due to deformation during mounting and assembly. there were.
[0012]
Further, when a plurality of flat type bobbinless coils are used in the field coil unit, there is a disadvantage that uneven torque occurs in the circumferential direction due to the magnetic saliency, and improvement on the coil side is also desired. It was.
[0013]
Further, the outer diameter of the bearing must be reduced as the outer diameter of the motor housing becomes smaller in design. However, due to bearing strength problems associated with smaller diameters, and when using sintered oil-impregnated bearings, the bearing volume should be larger in view of the theoretical oil retention of the bearing. There are many problems. For this reason, as a power feeding mechanism as shown in FIG. 4 capable of relatively increasing the bearing diameter, it is considered that power is fed from the outer diameter side of the housing 7 instead of the axial direction of the bearing holder 6. There was a drawback of increasing.
[0014]
Further, in order to prevent the field coil unit from dropping off to the rotor side, which may be generated by using a plurality of flat winding coils as separate bodies, the field coil 5 is disposed on the outer periphery of the substantially cylindrical body holder 15 or the cylinder. A structural component that is bonded and fixed to one surface of the cylindrical structure such as the inner peripheral portion of the flexible substrate 18 bent into a shape is indispensable.
[0015]
From the above, in order to reduce the size and diameter of motors, a new structure that is reliable with a power supply mechanism that does not take up space, is easy to assemble, and is mass-productive. It was desired.
[0016]
The present invention is an indispensable power feeding mechanism for miniaturization, miniaturization, and miniaturization of motors, so that the conductive wiring portion does not protrude in the cylindrical radial direction, and there is no fear of disconnection at the field coil tap wire portion. The present invention also provides a power supply mechanism for a small motor having a structure in which the rotational torque unevenness is small and the magnetic gap width can be set to a minimum.
[0017]
[Means for Solving the Problems]
The features of the present invention are mainly the structure of the power feeding mechanism on the stator side and the field coil for generating a magnetic field installed in the housing. That is, according to the present invention, in a small motor having an outer diameter of 3 mm or less, a field coil assembled by a tortoiseshell winding or the like with a cup-shaped or bell-shaped cylindrical winding coil is arranged on the winding coil portion inside the housing. Then, a field coil tap wire that is delta-connected or star-connected from the field coil is drawn out, and a connection terminal made of a conductive material is provided on the tap wire side of the field coil, and the field coil tap wire is connected to the connection terminal. A substantially cylindrical terminal holder made of an electrically insulative material is connected to one end side of the stator in which the entire conducting portion of the field coil and the connection terminal are fitted and fixed integrally with the housing in the same direction. The connection hole with the printed wiring on the other end of the connection terminal is attached to the connection hole of the flexible board with a ring shape and the wiring portion is a band. The flexible circuit board is sandwiched and fixed together with the connection terminal at the connection terminal cap part of the driver, and the field coil tap wire is connected to the connection hole part of the flexible circuit board through the connection terminal, and the outer peripheral part of the bearing holder This is a power supply mechanism for a small motor in which a flexible substrate is bent along a cutout portion of a cylindrical housing to form a power supply path portion.
[0018]
In other words, the power feeding mechanism of the present invention is a cage-type field magnet comprising a cup-type cylindrical winding coil or a bell-type cylindrical winding coil with respect to a field coil unit in which conventional flat bobbinless coils are connected. A plurality of phases are integrated using the coil 8, and the field coil tap wire 9 is connected in delta connection or star connection to the connection hole portion of the flexible substrate 13 via the connection terminal 10, respectively, and protrudes in the outer diameter direction. This is a power feeding mechanism that secures a conduction path by embedding the flexible substrate 13 along a notch formed at one end of the outer periphery of the housing 7.
[0019]
【Example】
An embodiment of the present invention will be described with reference to FIGS. 1, 2 and 5 which are design examples of a motor having an outer diameter of φ2 mm. In the figure, the components having the same reference numerals as those in FIGS. 3 and 4 are components having the same functions, and thus description thereof is omitted.
[0020]
In FIG. 1, reference numeral 8 denotes a field coil comprising a cup type cylindrical winding coil (or a bell type cylindrical winding coil or the like) used in a rotor rotor portion of a general cylindrical coreless motor. 8 and is inserted and fixed so as to fit into the inner diameter of the housing 7.
[0021]
A connection terminal 10 made of a conductive material is provided on the tap wire side of the field coil 8 of the cylindrical winding, and the field coil tap wire 9 is connected to the connection terminal 10 at the outer peripheral portion, and further electrically insulated. A substantially cylindrical terminal holder 11 made of a material holds the field coil 8 and the entire conducting portion integrally with the housing 7 in a coaxial direction and is fixedly fitted.
[0022]
Further, on the other end side of the connection terminal 10, a connection hole portion of the flexible substrate 13 in which the connection portion provided with the printed wiring is in a ring shape and the wiring portion is in a band shape is attached. The flexible substrate 13 is fixed to the housing 7 while being inserted so as to be sandwiched by the portion 12. FIG. 5 shows a detailed perspective view when the connection terminal 10 and the flexible substrate 13 are assembled. Note that the wiring pattern of the flexible substrate 13 and the shape of the connection hole are not limited to this. For example, the connection hole may be formed in a substantially U shape to facilitate positioning.
[0023]
According to this new structure, the field coil 8, the connection terminal 10, and the terminal holder 11 are integrally formed and inserted and fixed on the housing 7 side. No stress is applied, and disconnection from the connection terminal portion during assembly or during operation after assembly can be prevented.
[0024]
Further, the body of the cylindrical housing 7 has a substantially U-shaped cutout portion 180 extending from the drawing position of the flexible substrate 13 of the band-shaped portion as shown in FIGS. The flexible substrate 13 of the belt-like portion drawn in the circumferential direction is bent at a substantially right angle on the outer periphery of the bearing holder 6 and then stored in the recess in the notch portion 14. Stored. Therefore, if the thickness of the flexible substrate 13 is thinner than the housing thickness of the housing 7, no convex portion is formed in the outer peripheral diameter direction of the housing 7.
[0025]
In the design specifications of the present invention, the housing 7 which is a housing has an outer diameter of 2.0 mm, a thickness of 0.1 mm, and a flexible substrate 13 having a thickness of 0.08 mm. Convex portions are not formed in the outer peripheral radial direction, and the actual outer diameter dimension is kept within the minimum diameter.
[0026]
Further, in order to avoid a short circuit between the connection terminal 10 and the bearing 4 and the printed wiring portion of the flexible substrate 13, the bearing holder 6 is made of an electrically insulating material, and the connection terminal cap portion as shown in FIG. 12 is provided in part. Further, on the side surface of the bearing holder 6, two flat portions 20 respectively corresponding to the notches 14 of the housing 7 are provided.
[0027]
The field coil 8 is a cup-type winding (cage-type winding) used in a rotor rotor part of a general conventional cylindrical coreless motor, and the entire field coil 8 is integrally formed in a cylindrical shape. In terms of strength, it is strong with little deformation in the radial direction. In particular, even if it is not bonded to the inner diameter of the housing 7, it is fixed integrally with the terminal holder 11, so there is no deformation or dropout due to an external impact, and there is no concern of hindering the rotation operation of the rotor 1. .
[0028]
In addition, the function as a field coil for generating a rotating magnetic field is less than the conventional structure in which a plurality of flat winding coils are connected, and the magnetic gap is substantially less than the cylindrical structure of the cylindrical holder 15 or the flexible substrate 18. Since the width can be reduced, the torque generation efficiency is higher than that of the conventional type, and the diameter can be further reduced as a small motor.
[0029]
【The invention's effect】
As described in detail above, in the structure of the present invention, a cylindrical structure for fixing a field coil such as a substantially cylindrical holder or a flexible substrate is interposed between the rotor and the housing. Therefore, even if the diameters are the same, the magnetic gap width can be minimized in the structural design, and the magnetized torque can be obtained effectively.
[0030]
In addition, by using a squirrel-cage winding such as a cup-type cylindrical winding coil or a bell-type cylindrical winding coil as the field coil, the magnetic saliency is reduced structurally and the cylindrical circumferential direction is reduced. Generation torque unevenness can be reduced. Also, in terms of strength, the cup-type coil or bell-type coil has a cylindrical shape, so the coil alone is sufficiently strong, and as a field coil on the stator side, dropping and deformation to the rotor part is fundamental. Can be eliminated.
[0031]
Also, when designing with the smallest possible diameter reduction, by providing a notch in a part of the housing and storing the conduction path part in the recess, there will be no part protruding in the outer diameter direction of the housing, and the ultra-small diameter motor As a power supply mechanism, it is possible to maximize the benefits of reducing the diameter. The effect is particularly great when the outer diameter is less than 2.0 mm.
[0032]
Further, in the structure of the present invention, by supplying power supply wiring from the outer diameter side of the housing rather than in the axial direction of the bearing holder end surface, extra space is generated in the bearing holder radial direction, so the bearing diameter is reduced. The maximum dimension can be designed for the housing inner diameter.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view illustrating a power feeding mechanism of the present invention.
FIG. 2 is an external view of a motor to which a power supply unit flexible substrate according to the present invention is connected.
FIG. 3 is a cross-sectional view illustrating a conventional power feeding mechanism.
FIG. 4 is a cross-sectional view illustrating another conventional power feeding mechanism.
FIG. 5 is an assembled perspective view of the connection terminal feeding portion of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Rotor 2 Output shaft 3 Thrust board 4 Bearing 5 Field coil 6 Bearing holder 7 Housing 8 Field coil 9 Field coil tap wire 10 Connection terminal 11 Terminal holder 12 Terminal cap part 13 Flexible board 14 Notch part 15 Cylinder Body holder 16 Relay pin 17 Lead wire 18 Flexible substrate 19 Opening 20 Flat portion

Claims (1)

Outside diameter φ3 with housing as housing mm In the following small motors, a field coil assembled by a tortoiseshell winding or the like with a cup-shaped or bell-shaped cylindrical winding coil is arranged in the winding coil portion inside the housing, and delta connection from the field coil Alternatively, the field coil tap wire that is star-connected is pulled out, and a connection terminal made of a conductive material is provided on the tap wire side of the field coil, and the field coil tap wire is connected to the connection terminal and made of an electrically insulating material. With the substantially cylindrical terminal holder, the entire conducting portion of the field coil and the connection terminal is fitted and fixed to the housing in the same direction in the coaxial direction, and the printed wiring is connected to the other end of the connection terminal. The connection hole cap part of the bearing holder that is attached to the connection hole part of the flexible printed circuit board with the ring-shaped connection part and the wiring part is attached. The flexible board is sandwiched and fixed together with the connection terminal, the field coil tap wire is connected to the connection hole of the flexible board through the connection terminal, and the flexible board is attached to the cylindrical housing at the outer peripheral portion of the bearing holder. A power supply mechanism for a small motor, wherein a power supply path portion is formed by bending along a notch.

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