JP2000166157A - Power supply mechanism for small-sized motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide power supply mechanism of a small-sized motor having an outer diameter of 3 mm or less, wherein a conductor wiring part does not protrude in the cylinder direction, the possibility for disconnection in a field coil tap wire part does not exist, torque irregularity of rotation is small, and a magnetic gap width can be set to a minimum. SOLUTION: A cage field coil 8 constituted of a cup-type or belt-type cylinder wiring coil is arranged in a housing 7, and is connected with a connection terminal 10 on a tap wire 9 side. The field coil, the connection terminal, etc., are fitted collectively and fixed to the housing, in the coaxial direction, by using a cylindrical terminal holder 11 composed of electrically insulating material. A connection hole part of a flexible board 13 is fixed on the other side of the connection terminal by printed wiring. The flexible board is clamped and fixed together with the connection terminal by connection terminal cap parts 12 of facing bearing holders 9, In the outer peripheral part of the bearing holder 6, the flexible board is bent along a notched part of the housing, thereby forming a power supply path part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a micro motor having a very small diameter, such as a micro driving motor for a milli-machine and a vibration motor for a wrist watch having a silent vibration alarm function. It relates to a power supply mechanism.

[0002]

2. Description of the Related Art Conventionally, there has been a demand for a small cylindrical motor having an outer diameter of about 5 mm as a vibrating motor with a weight.
It has been mounted on mobile communication devices such as HS and mobile phones, or as a motor for driving device components, and has been put into practical use in various devices such as OA devices, precision devices, radio control models, etc., and has been put to practical use. In recent years, ultra-small motors have been developed for the purpose of mounting on precision medical equipment such as in-vivo diagnostic treatment or high-tech industrial equipment such as self-propelled in-pipe environment confirmation equipment. There is a growing demand, and the demand for ultra-small diameter and ultra-small size is increasing year by year.

However, the smaller and smaller the motor, the more difficult it is to manufacture and assemble each part, and also the structure, dimensions, arrangement and mounting of each part at the design stage, and the power supply wiring from the power supply side. This causes a problem of space saving of the routing mechanism. In particular, in the case of an ultra-small diameter motor having an outer diameter of 3 mm or less, it is important to reduce the diameter of the power supply wiring structure and to determine where to place the best installation point for reducing the diameter and space. It will be a point.

For this reason, brushless motors that do not require a brush and a commutator, which are structurally advantageous in terms of the size of the motor, are generally becoming the mainstream of motors. Because of its high energy efficiency and relatively easy manufacture, a brushless motor of a type having a permanent magnet type rotor and having a plurality of flat field coils on a cylindrical circumference is used.

FIGS. 3 and 4 show an example of a conventional brushless motor having this permanent magnet type rotor. In FIG. 3, reference numeral 1 denotes a rotor having an output shaft 2 at one end. The rotor 1 is rotatable by two bearings 4 mounted at the center of both ends of a housing 7 via a bearing holder 6 and a substantially cylindrical holder 15. It is supported by

[0006] Further, at least three or more single-piece bobbinless coils each formed by laminating a self-fusing wire in a flat ring shape are arranged on the inner peripheral surface of the cylindrical housing 7 at an equal angle in the circumferential direction. In a field coil unit for generating a rotating magnetic field, the rotor 1 rotates following a rotating magnetic field formed by each of the field coils 5. The flat field coil 5 is bent along the outer peripheral surface of the substantially cylindrical holder 15 in FIG. 3 and can be inserted and fixed to the inner diameter of the cylindrical housing 7 in an adhesively fixed state. In order to facilitate the assembly of a small motor, a device has been devised.

Reference numeral 9 shown in FIG. 3 denotes a tap wire drawn from the plurality of flat-shaped field coils 5, and is a metal relay pin mounted on an end of the substantially cylindrical holder 15. A lead wire 17 connected to one end of the power supply mechanism 16 and a lead wire connected to the drive circuit is connected to the other end of the power supply 16 to form a conduction path for the power supply mechanism. Reference numeral 3 denotes a thrust plate attached to the rotor 1, which is interposed in order to regulate a gap formed by the thrust plate 3 and the stator-side bearing 4 and to limit the play of the rotor 1 in the thrust direction. Is provided.

In another example of the configuration shown in FIG.
In the same manner as described above, in order to facilitate the assembly of the stator coil portion, one flexible substrate 1 on which circuit wiring is formed
The field coil 5 using three or more flat bobbinless coils is mounted on the upper surface 8, and the cylindrical winding portion of the flexible substrate 18 is bent and inserted into the inner surface of the housing 7 along the inner wall surface. Fixed. The bobbinless coils on these substrates are arranged at equal angles in the circumferential direction of the cylinder,
The structure is such that a rotating magnetic field is formed. The power supply wiring portion of the flexible substrate 18 is drawn out of the housing 7 through an opening 19 provided on the outer peripheral portion of the cylindrical housing of the housing 7 and connected to the drive circuit side while protruding to the outer periphery of the housing. Have been.

As described above, the power feeding mechanism for a small diameter motor based on a conventional brushless motor represented by FIGS. 3 and 4 is easy to assemble, requires a field coil tap during assembly or operation. To prevent disconnection of the wire 9 or to prevent the field coil unit from dropping to the rotor side, which can be caused by using a plurality of flat winding coils separately from the field coil 5, the same field coil 5 is generally used. After adhesively fixing to one surface of the cylindrical structure such as the outer peripheral portion of the cylindrical holder 15 or the inner peripheral portion of the flexible substrate 18 bent into a cylindrical shape,
It was common to insert and fix it to the inside diameter of the housing 7.

[0010]

However, in the above-described conventional structure, even if the field coil 5 has the same flat winding form and the rotor magnet has the same performance, the design of the rotating coil is not sufficient. In the case of the configuration shown in FIG. 3, a substantially cylindrical holder 15 is provided between the child 1 and the housing 7, and in the case shown in FIG. , The permeance coefficient naturally decreases, and the torque generated by the rotor 1 decreases.

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, a projection is exposed on a part of the outer diameter of the housing 7 by the thickness of the flexible substrate 18. Therefore, there is a disadvantage in that the outer diameter dimension is increased such that the benefit of the extremely small diameter is impaired. In addition, even in the case of using the lead wire 17 in FIG. 3, there is a soldering work for connection with the relay pin 16, the wire diameter of the lead wire is thin, and there is a fear of defective conduction and disconnection due to deformation at the time of mounting and assembling. there were.

Further, when a plurality of flat-type bobbinless coils are used in the field coil unit, there is a disadvantage that torque unevenness in the circumferential direction occurs due to the magnetic saliency, and the coil side is improved. Was also desired.

Also, due to the design, the smaller the outer diameter of the motor housing, the smaller the outer diameter of the bearing.
However, due to the problem of bearing strength due to the reduction in diameter, and when using a sintered oil-impregnated bearing, the larger the bearing volume, the better from the theoretical oil retention of the bearing. There are many problems. For this reason, as a power supply mechanism as shown in FIG.
It has been considered that power is supplied from the outer diameter side, but there is a disadvantage that the outer diameter dimension increases.

Further, in order to prevent the field coil unit from dropping to the rotor side, which can be caused by using a plurality of flat wound coils separately, the same field coil 5 is mounted on the outer peripheral portion of the substantially cylindrical holder 15. Alternatively, a structural component that is adhered and fixed to one surface of the cylindrical structure, such as the inner peripheral portion of the flexible substrate 18 bent into a cylindrical shape, is indispensable.

From the above, in order to promote the miniaturization and ultra-small diameter of the motor, a new power supply mechanism that is structurally occupied, has high reliability, has a long life, is easy to assemble, and has mass productivity. A simple structure was desired.

The present invention provides a power supply mechanism indispensable for downsizing, ultra-small diameter, and downsizing of a motor, in which a conductive wiring portion does not protrude in a cylindrical radial direction and a disconnection at a field coil tap wire portion. There is no worry, there is little rotation torque unevenness,
Another object of the present invention is to provide a power supply mechanism for a small motor having a structure capable of setting a magnetic gap width to a minimum.

[0017]

The features of the present invention mainly reside in the structure of the power supply mechanism on the stator side and the field coil for generating a magnetic field installed in the housing. That is, the present invention provides an outer diameter φ
In a small motor of 3 mm or less, a cage-type field coil composed of a cup-type cylindrical winding coil or a bell-type cylindrical winding coil is disposed in a winding coil portion inside a housing, and a tap wire of the field coil is provided. A connection terminal made of a conductive material is provided on the side, a field coil tap wire is connected to the connection terminal, and the entire conducting portion between the field coil and the connection terminal is formed by a substantially cylindrical terminal holder made of an electrically insulating material. Is one end of the stator fitted and fixed integrally to the housing in the coaxial direction, and the other end of the connection terminal is connected to a flexible substrate having a ring-shaped connection portion and a wiring portion having a strip-shaped wiring portion. The hole is attached, and the flexible board is fitted and fixed together with the connection terminal at the connection terminal cap part of the bearing holder facing, and at the outer peripheral part of the bearing holder, The serial flexible substrate is bent along the cut-out portion of the cylindrical housing is a feed mechanism of a miniature motor forming the feeding path portion.

That is, the power supply mechanism of the present invention is a cage type comprising a cup-shaped cylindrical winding coil or a bell-type cylindrical winding coil with respect to a conventional field coil unit connected with a flat bobbinless coil. A plurality of phases are integrated using the field coil 8, and the field coil tap wires 9 are connected in a delta connection or a star connection to the connection holes of the flexible substrate 13 via the connection terminals 10, respectively. This is a power feeding mechanism that secures a conduction path by embedding a protruding strip-shaped flexible substrate 13 along a cutout formed at one end of the outer periphery of the housing 7.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 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 2 mm. In the drawings, components having the same reference numerals as those in FIGS. 3 and 4 are components having the same functions, and thus description thereof will be omitted.

In FIG. 1, reference numeral 8 denotes a cup-shaped cylindrical coil (or a cage-type coil such as a bell-type cylindrical coil) used for a rotor rotor of a general cylindrical coreless motor. The field coil 8 is inserted and fixed so as to fit into the inner diameter of the housing 7.

A connection terminal 10 made of a conductive material is provided on the tap wire side of the field coil 8 having a cylindrical winding.
A field coil tap wire 9 is connected to the connection terminal 10 at an outer peripheral portion, and furthermore, the entire conductive portion together with the field coil 8 is coaxially integrated with the housing 7 by a substantially cylindrical terminal holder 11 made of an electrically insulating material. And is fitted and fixed.

On the other end side of the connection terminal 10, a connection hole portion of a flexible substrate 13 having a ring-shaped connection portion with printed wiring and a strip-shaped wiring portion is attached to the other end of the connection terminal 10. The flexible substrate 13 is fixed to the housing 7 while being inserted so as to be covered by the connection terminal cap portion 12. FIG. 5 shows the connection terminal 1
0 and a detailed perspective view when the flexible substrate 13 is assembled. The shape of the wiring pattern and the connection hole of the flexible substrate 13 is not limited to this. For example, the connection hole may be substantially U-shaped to facilitate positioning.

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 to the housing 7 side. No stress such as bending is applied, and disconnection with the connection terminal portion during assembly or during operation after assembly can be prevented.

FIG. 2 shows the main body of the cylindrical housing 7.
In addition, as shown in FIG. 5, two substantially U-shaped notches 14 are provided in the 180-degree direction from the position where the flexible substrate 13 is pulled out of the belt-shaped portion to the outside of the opening at the end of the cylinder. The flexible substrate 13 of the belt-like portion drawn out in the direction is bent at a substantially right angle around the outer periphery of the bearing holder 6, and then is accommodated in the recess in the cutout portion 14 and stored. Therefore, if the thickness of the flexible substrate 13 is smaller than the thickness of the housing of the housing 7, no protrusion is formed in the outer circumferential direction of the housing 7.

According to the design specifications of the present invention, the outer diameter of the housing 7, which is a housing, is φ2.0 mm, the thickness is 0.1 mm, and the thickness of the flexible substrate 13 is 0.08 mm. The projection is not formed in the outer diameter direction of the housing 7, and the actual outer diameter is within the minimum diameter.

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 as shown in FIG. The terminal cap part 12 is provided in a part. Further, on the side surface of the bearing holder 6, flat portions 20 corresponding to the cutout portions 14 of the housing 7 are provided.
Are provided in two places.

The field coil 8 is a cup-type winding (cage winding) as used in a rotor rotor of a general conventional cylindrical coreless motor. Integral in shape, strong in strength with little deformation in the radial direction. In particular, even if it is not adhered to the inner diameter of the housing 7, it is fixed integrally with the terminal holder 11, so there is no deformation or falling off due to an external impact, and there is no concern that the rotation operation of the rotor 1 is hindered. .

The function as a field coil for generating a rotating magnetic field is also smaller than that of a conventional series of a plurality of flat-wound coils because of the absence of the cylindrical structure of the substantially cylindrical holder 15 or the flexible substrate 18. Since the width of the magnetic gap can be reduced, torque generation efficiency higher than that of the conventional type can be obtained, and the diameter of the motor can be reduced.

[0029]

As described above in detail, in the structure of the present invention, a cylinder for adhering and fixing a field coil, such as a substantially cylindrical holder or a flexible substrate, between a rotor and a housing, as conventionally known. Since there is no intervening structure, the magnetic gap width can be minimized in the structural design even if the diameters are the same, and a magnetically generated torque can be obtained effectively.

Further, by using a cage type 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 in structure, and The generated torque unevenness in the circumferential direction can be reduced. In terms of strength, the cup-type coil or bell-type coil has a cylindrical shape, so it is sufficiently strong as a single coil, and as a field coil on the stator side, the dropout / deformation to the rotor part is fundamental. Can be eliminated.

When the diameter is designed to be as small as possible, a cutout is provided in a part of the housing and the conduction path is accommodated in the recess, so that there is no part protruding in the outer diameter direction of the housing. As a power supply mechanism for an ultra-small diameter motor, the benefit of reducing the diameter can be maximized. In particular, the effect is greater when the outer diameter is 2.0 mm or less.

Further, in the structure of the present invention, since the power supply mechanism is provided with the power supply wiring not from the axial direction of the end face of the bearing holder but from the outer diameter side of the housing, an extra space is created in the radial direction of the bearing holder. The bearing diameter can be designed to the maximum size with respect to the housing inner diameter.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a power supply mechanism of the present invention.

FIG. 2 is an external view of a motor to which a power supply unit flexible board according to the present invention is connected.

FIG. 3 is a cross-sectional view illustrating a conventional power supply mechanism.

FIG. 4 is a cross-sectional view illustrating another conventional power supply mechanism.

FIG. 5 is an assembled perspective view of a connection terminal power supply portion of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Rotor 2 Output shaft 3 Thrust plate 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 substrate 14 Notch part 15 Substantially cylindrical Body holder 16 Relay pin 17 Lead wire 18 Flexible board 19 Opening 20 Flat part

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5H019 AA07 CC03 DD07 5H604 AA08 BB01 BB17 CC01 CC04 CC11 QB03 QB04 QB12 5H605 BB05 CC01 CC03 CC10 EA07 EC05 EC12 5H621 BB06 GB09 HH01 JK01 JK13

Claims (2)

[Claims] 1. A small-sized motor having an outer diameter of 3 mm or less and having a housing as a housing, a cage-shaped field formed of a cup-shaped cylindrical winding coil or a bell-shaped cylindrical winding coil in a winding coil portion inside the housing. A magnetic coil is disposed, 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 a substantially cylindrical terminal holder made of an electrically insulating material is provided. Thus, the entire conducting portion of the field coil and the connection terminal is coaxially and integrally fitted and fixed to the housing at one end of the stator, and the other end of the connection terminal is provided with a printed wiring at the other end. The connection hole of the flexible board with the ring shape and the wiring part of the belt shape is attached, and the flexible board is sandwiched together with the connection terminal by the connection terminal cap part of the bearing holder facing to the connection hole. Fixedly fitted in the outer peripheral portion of the bearing holder, small motor feed mechanism, characterized in that the formation of the cutout feeding path portion is folded along the portion of the flexible cylindrical housing substrate. 2. A field coil comprising an integral cup-shaped cylindrical winding coil or a bell-shaped cylindrical winding coil,
2. A field coil tap wire having a cylindrical winding coil shape assembled by a tortoise winding or the like, and a delta connection or a star connection field coil tap wire is connected to a connection hole of a flexible substrate via a connection terminal. Small motor as described.