JP2006254663A5 - - Google Patents

Description

motor

  The present invention relates to a motor. More specifically, the present invention relates to welding of a motor case.

  As shown in FIG. 10, spot welding or laser welding is employed to fix the motor case 100 of the motor and the mounting plate 101 to which the motor case 100 is attached. For example, when spot welding is performed, three or more convex portions are formed on the motor case 100, and the convex portions are melted and welded by energizing the mounting plate 101 while applying pressure.

Here, although the convex portion can be provided on the mounting plate 101, the mounting plate 101 is a custom part for each customer, so the shape of the convex portion varies from model to model, and welding becomes unstable. End up. For this reason, a convex part is provided in the motor case 100 which is a common part.

  On the other hand, in recent years, motors have been miniaturized, and motors having a diameter of about 5 mm have been developed.

JP 2004-112985 A

  However, in the motor using spot welding described above, it is difficult to accurately process the convex portion on the motor case 100 or the mounting plate 101 especially when the motor diameter is less than 6 mm. It has become difficult.

  Further, in laser welding, since the diaphragm R surface 101a of the motor case 100 and the mounting plate 101 are welded, it is difficult to focus the laser at the welded portion due to the influence of the diaphragm R surface 101a of the motor case 100, and the welding is unstable. This makes it impossible to achieve mass productivity.

  Accordingly, an object of the present invention is to provide a motor capable of welding a motor case and a mounting plate even if it is a small motor.

In order to achieve the above object, the present invention provides a motor having an opening and a mounting plate for mounting the motor case, and a mounting surface of the motor case opening section in cross section. The flat surface of the working plate is fixed by laser welding .

According to the present invention, since the laser is irradiated to the opening of the motor case, it is not affected by the shape of the R surface of the motor case, and the laser can be irradiated from the vertical direction and the horizontal direction with respect to the motor case. Therefore, since the laser focusing at the welded portion is simplified, it is possible to prevent uneven welding of the motor case and the mounting plate due to the laser being out of focus. Furthermore, since the motor case and the mounting plate are welded to each other, stable welding can be ensured.

  In the present invention, the motor case houses a rotor portion having a rotating shaft and a rotor magnet, and a stator portion disposed opposite to the rotor magnet via a gap, and the stator portion includes a plurality of poles. A first stator core formed with teeth and a second stator core formed with a plurality of pole teeth; an outer periphery of the pole teeth of the first stator core and an outer periphery of the pole teeth of the second stator core Can be applied to a motor in which an annular air-core coil is arranged.

  In the present invention, the motor case includes a first motor case that houses the first stator core and a second motor case that houses the second stator core, and the opening has a cylindrical shape. It is preferable that the first motor case and the second motor case formed on each other are formed by shearing two opposing surfaces of the peripheral side surfaces. If comprised in this way, since the opening part is formed by shearing the two surfaces where the circumferential side faces each other, the motor case can be reduced in size.

  In the present invention, it is preferable that the first motor case and the second motor case also serve as another first stator core and another second stator core. If comprised in this way, since a motor case serves as a stator core, size reduction of a motor can be achieved.

  In the present invention, it is preferable that the laser welding is performed by irradiating a laser on a section of the opening that is in contact with a plane of the mounting plate of the first motor case.

According to the present invention , since focusing of the laser at the welded portion is simplified, it is possible to prevent uneven welding of the motor case and the mounting plate due to the laser being out of focus. The deformation of the mounting plate can be prevented to improve the yield during motor manufacture.

Furthermore, since the motor case and the mounting plate are welded to each other, stable welding can be ensured. Therefore, the accuracy and strength of the motor can be increased.

(Motor structure)
FIG. 1 is a cross-sectional view of a main part of a PM (permanent magnet) type stepping motor to which the present invention is applied.

  FIG. 2 is an explanatory view showing the structure of the stator portion 3 of the stepping motor 1 shown in FIG.

(Motor configuration)
A stepping motor 1 according to the present embodiment shown in FIG. 1 includes a rotor portion 2 having a rotating shaft 21 and a rotor magnet (permanent magnet) 22, and a stator portion 3 arranged to face the rotor magnet 22 via a gap. The rotary shaft 21 is rotatably supported by the bearing 4 and is spring-biased in the axial direction by a spring member 5 that abuts one end of the rotary shaft 21. The support on the other end side of the rotating shaft 21 is rotatably supported by a bearing (not shown) different from the bearing 4. This other bearing is provided, for example, in the vicinity of the outlet end opening of the first stator core 31 or the opening inside the mounting plate, or is provided at the tip of the rotating shaft 21 via a casing (not shown).

  A rotor magnet 22 is fixed to the rotating shaft 21 by adhesion on the rotating shaft 21 constituting the rotor unit 2, and the rotor magnet 22 is formed of a substantially cylindrical permanent magnet.

  Further, the rotor magnet 22 is formed with circular recesses on both end surfaces in the axial direction, and the rotor magnet 22 itself is further reduced in weight by forming these recesses. Thus, the inertia moment of the rotor magnet 22 is reduced by reducing the weight.

  The other end of the rotating shaft 21 is an output shaft extended so as to output the rotation of the stepping motor 1.

  The stator portion 3 is configured in a two-phase structure by a first stator core 31 and a second stator core 32 fixed back to back with the first stator core 31.

  The first and second stator cores 31 and 32 are configured such that a plurality of pole teeth are alternately arranged. The outer peripheral part of these pole teeth and the chrysanthemum between the pole teeth are chamfered. For this reason, the insulation defect of the air-core coils 33 and 34 due to the burr of the pole teeth can be reduced. The size of the burr is preferably set to 0.03 mm or less by the chamfering process here.

  An annular air core coil 33 is disposed on the outer periphery of each pole tooth in the first stator core 31. Similarly, an annular air core coil is disposed on the outer periphery of each pole tooth in the second stator core 32. 34 is arranged.

  An insulating film 50 that enhances insulation is formed on the entire surface of the annular air-core coils 33 and 34.

  Furthermore, an insulating sheet 40 is interposed between the first stator core 31 and the air-core coil 33. In the present embodiment, the insulating sheet 40 is bonded to the first stator core 31 and the air core coil 33 using an adhesive. It is fixed to the air core coil 33.

  Similarly, an insulating sheet 40 is fixed between the second stator core 32 and the air-core coil 34 using an adhesive.

The stepping motor 1 includes first and second stator core 31, the air-core coils 33 and 34 are assembled to the first and second stator core 31, winding of the air core coil 33 and 34 terminals 33a, be one 34a and a plurality of terminal pins 36 is wound with the terminal block 35 is provided, the fitting portion 35a of the terminal block 35 is the first and, as shown in FIGS. 3 and 4 A gap 41 is provided between the terminal block 35 and the air-core coils 33, 34 while being fitted to the fitting portions 31 b, 32 b of the second stator cores 31, 32.

The fitting portion 35a of the terminal block 35 is a through hole. Further, the fitting portions 31 b and 32 b of the first and second stator cores 31 and 32 are formed of protrusions that are press-fitted into the fitting portions 35 a of the terminal block 35 . Thereby, it is possible to easily assemble and prevent the terminal block 35 from falling. As shown in FIG. 5, the terminal pin 36 is made of a metal L-shaped pin. The terminal pin 36 is insert-molded together with an insulating material made of a liquid crystal polymer to form a terminal block 35. High heat resistance can be obtained by using a liquid crystal polymer.

The terminal pins 36 are arranged in a square shape. Accordingly, the length of the terminal block 35 in the circumferential direction of the motor can be shortened as compared with the case where it is arranged in a straight line as in the prior art, so that the stepping motor 1 can be downsized.

Each terminal pin 36 is provided in a direction parallel to the radial direction of the stepping motor 1. A base portion 36 a of each terminal pin 36 is provided toward the axial direction of the stepping motor 1 and slightly protrudes from the terminal block 35. For this reason, since wiring is also possible for the base portion 36a of the terminal pin 36 , for example, even when wiring to the terminal pin 36 is impossible due to installation space, wiring can be made to the base portion 36a of the terminal pin 36 . Even after the stepping motor 1 is installed in the apparatus, the electrical characteristics of the stepping motor 1 can be confirmed using the base portion 36a of the terminal pin 36 . Furthermore, since the terminal pin 36 is L-shaped, the strength against disconnection is extremely strong.

A plurality of protrusions 42 are formed around the fitting portion 35a of the terminal block 35 on the side to be fitted to the fitting portions 31b, 32b of the first and second stator cores 31, 32. As a result, as shown in FIG. 5 (a), the terminal 33a of the winding can be prevented from coming into contact with the edge of the through-hole for taking out the winding of the motor case 37, and disconnection due to the edge can be prevented. . Further, the protrusion 42 is caught on the edge of the motor case 37, so that the terminal block 35 can be prevented from falling.

Further, a step portion 43 is formed around the terminal pin 36 of the terminal block 35, and winding terminals 33 a and 34 a are wound around the terminal pin 36 along the step portion 43. Therefore, as shown in FIGS. 4 and 6 , since the terminal 33a of the winding reaches the terminal pin 36 in the stepped portion 43, the portion immediately before reaching the terminal pin 36 of the winding even if the FPC 44 or the like is attached later. 33b does not interfere. Thereby, there is no possibility that the said part 33b will be cut | disconnected by FPC44, and the yield at the time of attaching the stepping motor 1 can be raised.

  Further, the first stator core 31 is housed in another first stator core 37, and similarly, the second stator core 32 is housed in another second stator core 38.

  In the present embodiment, the other first stator core 37 also functions as a motor case, and will be referred to as a first motor case 37 below. Similarly, another second stator core 38 is described as a second motor case 38.

  As shown in FIG. 1, the first and second stator cores 31, 32, the first motor case 37, and the second motor case 38 are disposed concentrically with the axis of the rotary shaft 21, and are fixed by welding. ing.

Here, the stepping motor 1 is a mounting for attaching the first motor case 37 and the second motor case 38 having an opening portion 46 as shown in FIGS. 7 and 8, the first motor case 37 The flat surface of the first motor case 37 in contact with the mounting plate 45 and the flat surface of the mounting plate 45 are fixed by laser welding.

The first motor case 37 and the second motor case 38 are formed into a cylindrical shape with a bottom by drawing, and are formed so that two opposite surfaces of the peripheral side surface are sheared in the axial direction so that the bottom surface 37a becomes an oval shape. Has been. The mounting plate 45 is sufficiently larger than the bottom surface 37 a of the first motor case 37. Then, as shown in FIG. 8, laser welding is performed from the direction along the axial direction to the step portion between the bottom surface 37a of the first motor case 37 and the mounting plate 45 (reference numeral 47 in the drawing is a welding location). . The position and number of the welding locations 47 can be set as appropriate.

  In the present embodiment, as shown in FIG. 1 and FIG. 2, the axial length X formed by the first stator core 31 and the first motor case 37 and the axial length of the air-core coil 33. The relationship between the thickness Y and the thickness Z of the insulating sheet 40 is X> Y + Z.

A gap S is formed between the end surface of the first motor case 37 in the axial direction and the end surface of the air-core coil 33 facing the end surface in order to ensure insulation. A gap S is similarly formed in the axial direction between the second motor case 38 and the air-core coil 34.

  The bearing 4 is formed of a resin having lubricity, and supports one end of the rotating shaft 21 so as to be rotatable in the radial direction.

The bearing 4 for supporting the radial direction, a bearing portion for supporting the rotary shaft 21 which is inserted, the flange portion and the press-fitting portion for press-fitted into the inner diameter of the second stator core 32, a part of the outer peripheral portion projecting radially And are formed.

  The bearing portion of the bearing 4 is disposed so as to enter a recess formed in the rotor magnet 22, and the axial dimension of the entire stepping motor 1 is suppressed.

  Further, the inner diameter of the bearing portion is large enough to form a clearance as compared with the outer diameter of the rotating shaft 21.

  Further, the collar portion of the bearing 4 is placed on the second stator core 32 and is positioned in the axial direction.

  The spring member 5 is formed of a single metal plate, and is provided with a spring piece that comes into contact with one end of the rotating shaft 21 and a center hole.

  The spring member 5 is welded and fixed to the second motor case 38.

The spring piece of the spring member 5 is in contact with one end of the rotating shaft 21 and urges the rotating shaft 21 in the axial direction.

  Next, the air-core coil and the insulating sheet constituting the stator portion will be described with reference to FIG.

  In the present embodiment, the stator unit 3 is composed of two sets, but has the same structure, and therefore the first stator core 31 will be described here, and the description of the second stator core 32 will be omitted.

  The air-core coil 33 fitted to the first stator core 31 is obtained by applying an insulating film 50 to the entire surface of a coil winding that is wound a plurality of times.

  The coil winding has a thin self-bonding layer formed on the surface thereof, and heat is applied to melt the self-bonding layer so that adjacent coil windings are fixed to each other.

  In addition, the insulating film 50 formed on the entire surface of the coil winding wound a plurality of times is a paint mainly composed of polyamideimide resin in the present embodiment.

  The air core coil 33 is manufactured as follows.

  First, the coil winding is wound around a bar material serving as a winding core, the winding start end 33a and the winding end end 33a being exposed on the surface of the winding layer, so that a predetermined motor torque can be obtained. The

  In addition, the bar used as the winding core has an outer diameter that is substantially the same as that of the outer periphery formed by a plurality of pole teeth formed on the first stator core 31.

  During the winding, hot air is blown from the outside during winding, and the winding is self-fused at the same time as winding, and the coil windings wound on the winding core are bonded to each other. After the fusion, the winding rod is pulled out, and the wound coil winding is formed in the air-core coil 33.

  In the self-bonding of the winding, after winding, a predetermined voltage is applied between the winding start end 33a and the winding end 33a, current is passed through the coil winding to generate heat, and the surface of the coil winding is applied. These self-bonding layers may be fused and solidified, and the coil windings wound on the core may be bonded together.

  Next, the insulating film 50 is formed on the surface of the air-core coil 33 by dipping coating.

  Briefly, in the dipping coating, the air-core coil 33 is dipped in a paint tank mainly composed of polyamideimide resin, pulled up, blown off using an air blow, and dried. The above steps are repeated until a predetermined film thickness, for example, a film thickness of about 30 μm in this embodiment is secured. The thickness of the insulating film is preferably equal to or greater than the size of burrs and sink marks of the stator core to which the air-core coil is fitted or fixed. On the other hand, if the insulating film is thickened, the coil becomes large, so that the thickness is preferably 100 μm or less.

  An insulating sheet 40 is interposed between the end surface 33 h in the axial direction of the air-core coil 33 and the end surface 31 a of the first stator core 31.

The insulating sheet 40 has a ring shape, and in the present embodiment, the material is polyethylene terephthalate. In the present embodiment , the thickness of the insulating sheet 40 is 16 μm, but the withstand voltage is 100 V or more, and a good insulating performance can be ensured.

  The insulating sheet 40 has toughness compared to the insulating film 50.

  Further, in the present embodiment, the inner diameter of the insulating sheet 40 is substantially the same as the outer circumference of the plurality of pole teeth of the first stator core 31, and the outer diameter thereof is the outer diameter of the first stator core 31. It has a smaller diameter.

  By making it smaller than the outer diameter of the first stator core 31, the first stator core 31 and the second stator core 32 are not disturbed when they are welded.

  Furthermore, the air-core coil 33, the insulating sheet 40, and the first stator core 31 are fixed using an adhesive. By fixing, it can prevent that the air-core coil 33 moves to an axial direction, and contacts the end surface of the 1st motor case 37 which opposes an axial direction.

Further, in the dipping coating, the corners 33d, 33e, 33f, and 33g are less likely to be coated than the outer peripheral surface 33b and the inner peripheral surface 33c of the air-core coil 33, and are easily blown away by air blow. For this reason, the corners 33d, 33e, 33f, and 33g may be thinner than the outer peripheral surface 33b and the inner peripheral surface 33c.

  That is, when burrs or the like remain on the end surface 31a of the first stator core 31, and because the root portions of the plurality of pole teeth of the first stator core 31 have an R shape, the air core coil 33 is fitted. When they are combined, there is a possibility that the insulating film 50 is peeled off by the burr or R portion, the coil winding and the first stator core 31 are short-circuited, or the coil winding is disconnected.

  However, by interposing the insulating sheet 40, the insulating sheet 40 has toughness compared to the insulating film 50, so even if it contacts the burr generated in the first stator core 31, it does not break, It is designed to cover Bali.

For this reason, the insulating sheet 40 compensates for the thickness of the insulating film 50 on the end surface 33h (including the corner portions 33d, 33e, 33f, and 33g ) of the air-core coil 33. Insulation can be secured.

  When assembling the stepping motor 1 described above, the first stator core 31 (or the second stator core 32) from which the first motor case 37 (or the second motor case 38) has been removed is insulated as shown in FIG. The sheet 40 is fixed with an adhesive.

After bonding, the air core coil 33 (or air core coil 34) is fitted to the outer periphery of the pole teeth of the first stator core 31 (or second stator core 32), and the air core coil 33 is bonded and fixed. Then, the terminal block 35 is press-fitted into the fitting portions 31b and 32b of the first and second stator cores 31 and 32 and temporarily fixed. Further, the terminals 33 a and 34 a of the air-core coils 33 and 34 are wound around the terminal pin 36.

Next, the stator part 3 is assembled by attaching the first motor case 37 (or the second motor case 38). As shown in FIG. 1, the stator portion 3 is assembled so as to face the rotor magnet 22 with a gap therebetween. Here, the terminal block 35 is bonded to the first and second motor cases 37 and 38 and fixed.

The assembly of the stepping motor 1 is the same as that of a conventionally known stepping motor or the like, and thus detailed description thereof is omitted here.
(Other embodiments)

In addition, although the form mentioned above is an example of the suitable form of this invention , it is not limited to this, In the range which does not deviate from the summary of this invention, various deformation | transformation implementation is possible.

For example, in this embodiment, laser welding is performed from the direction along the axial direction, but the present invention is not limited to this and may be performed from an oblique direction. Although in the embodiments described above the mounting plate 45 are made sufficiently larger than the bottom surface 37a of the first motor case 37, to which as shown in FIG. 9 is not limited, the mounting plate 45 first motor The width may be the same as the bottom surface 37 a of the case 37. In this case, the laser irradiation direction is preferably a direction orthogonal to the axial direction, that is, a direction parallel to the mounting plate 45.

  In this embodiment, a stepping motor is used as a motor. However, the present invention is not limited to this, and other types of motors may be used.

For example, in the present embodiment, the base portion 36a of the terminal pin 36 is provided in the axial direction of the stepping motor 1, but is not limited thereto and may be in the circumferential direction. Moreover, although the edge part of the base part 36a of the terminal pin 36 protrudes from the terminal block 35, it does not need to protrude. Further, in the present embodiment, the protrusion 42 and the stepped portion 43 are provided on the terminal portion 35, but these may be omitted and may be provided as necessary.

  In the present embodiment, the terminal pins 36 are insert-molded together with an insulating material made of a liquid crystal polymer. However, the present invention is not limited to this, and insert molding using other materials may be used. Alternatively, the terminal pin 36 may be provided on the terminal block 35 by press fitting or the like.

Further, in the present embodiment, the stepping motor 1 having the first and second stator cores 31 and 32 is used. However, the present invention is not limited to this, and one stator core may be used. Further, although the stepping motor 1 without a bobbin using an air-core coil as the drive coil is adopted, the stepping motor 1 is not limited to this and may have a bobbin wound with a coil.

  In the present embodiment, the material of the insulating sheet 40 is polyethylene terephthalate, but is not limited to this, and may be polyester, polyamideimide resin, or the like.

  When the insulating sheet 40 is formed of the same polyamideimide resin as that of the insulating film 50, the stepping motor 1 having excellent insulating properties and heat resistance can be configured.

  Moreover, in this Embodiment, although the insulating sheet 40 is being fixed using the adhesive agent, it is not restricted to this, You may make it fix by press-fit etc., without adhering.

  Furthermore, in the present embodiment, the insulating sheet 40 has a ring shape, but is not limited to this, and may have other shapes such as being provided in pieces.

(Stepping motor operation)
In the stepping motor 1 configured as described above, a predetermined current is supplied to the air-core coils 33 and 34 of the stator unit 3, thereby causing a rotor magnet to generate magnetic interaction between the stator unit 3 and the rotor magnet 22. 22 is urged to rotate, and the rotating shaft 21 integral therewith rotates. Since the operation of the stepping motor 1 is the same as that of a conventionally known stepping motor or the like, detailed description thereof is omitted here.

The first motor case 37 having an opening 46, in the motor having a mounting plate 45 for mounting the first motor case 37, in contact with the mounting plate 45 of the opening cross section of the first motor case 37 The flat surface and the flat surface of the mounting plate 45 are fixed by laser welding.

Therefore, since the laser is applied to the opening 46 of the first motor case 37, it is not affected by the shape of the R surface of the first motor case 37 and the vertical direction and the horizontal direction with respect to the first motor case 37. Laser irradiation is possible from the direction. Therefore, since the focusing of the laser beam at the welding spot 47 is simplified, it is possible to prevent the uneven welding of the first motor case 37 and the mounting plate 45 caused by the laser beam being out of focus. Furthermore, since the planes of the first motor case 37 and the mounting plate 45 are welded to each other, stable welding can be ensured.

As described above, the focusing of the laser at the welding point 47 is simplified, so that it is possible to prevent the uneven welding of the first motor case 37 and the mounting plate 45 due to the laser being out of focus. In addition, the first motor case 37 and the mounting plate 45 can be prevented from being deformed, and the yield at the time of manufacturing the motor can be improved.

Furthermore, since the planes of the first motor case 37 and the mounting plate 45 are welded to each other, stable welding can be ensured. Therefore, the accuracy and strength of the motor can be increased.

It is a sectional side view showing the outline of a stepping motor. It is an exploded view showing an air core coil and an insulating sheet. It is a front view which shows the relationship between a terminal block and a stator. It is a top view which shows the relationship between a terminal block and a stator. It is a figure which shows a terminal block, (a) is the II sectional view taken on the line in (b), (b) is a top view, (c) is the II-II sectional view in (b), (d) is a bottom face It is a figure. It is a side view which shows the detail of a step part. It is a figure which shows a motor, (a) is a side view, (b) is a bottom view. It is a bottom view showing welding of the motor case and mounting plate of the present invention. It is a figure which shows welding with the motor case of another example, and a mounting plate, (a) is a side view, (b) is a bottom view. FIG. 6 is a side view showing welding between a conventional motor case and a mounting plate.

Explanation of symbols

1 Stepping motor 37 Motor case 45 Mounting plate 46 Opening

Claims (5)

  In a motor having a motor case provided with an opening and a mounting plate for mounting the motor case, a plane in contact with the mounting plate in a cross section of the opening of the motor case and a plane of the mounting plate are laser-welded. It is fixed by the motor.   In claim 1, in the motor case, a rotor portion provided with a rotating shaft and a rotor magnet, and a stator portion disposed opposite to the rotor magnet via a gap are housed.
  The stator portion has a first stator core formed with a plurality of pole teeth and a second stator core formed with a plurality of pole teeth,
  An annular air core coil is disposed on the outer periphery of the pole teeth of the first stator core and the outer periphery of the pole teeth of the second stator core.   In Claim 2, the motor case comprises a first motor case that houses the first stator core, and a second motor case that houses the second stator core,
  The motor according to claim 1, wherein the opening is formed by shearing two opposing surfaces of the first motor case and the second motor case formed in a cylindrical shape.   4. The motor according to claim 3, wherein the first motor case and the second motor case also serve as another first stator core and another second stator core.   5. The motor according to claim 3, wherein the laser welding is performed by irradiating a laser on a section of the opening that is in contact with a plane of the mounting plate of the first motor case.