JP2005073409A - Stepping motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a stepping motor where a motor case and a stator can be fixed simply and stably. <P>SOLUTION: This stepping motor is equipped with a substantially cylindrical motor case 2 with its one end closed, a cover 3 which is set to block the opening of the motor case, a stator structure 4 which consists of a stator 5 having substantially the same outside diameter as the bore of the motor case and being housed in the motor case, with many magnetic pole pieces formed along its inner edge, and a coil body 6 where coils corresponding to each magnetic pole piece are arranged and which magnetizes and demagnetizes each magnetic pole piece in order, and a rotor structure 8 which is housed rotatably in the magnetic space part, constituted of each magnetic pole piece of the stator. A caulking part 12 is formed at the position of the periphery of the motor case, corresponding to a cut 13 made at the peripheral edge of the stator so as to caulk the periphery of the stator and the internal perimeter of the motor case. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a stepping motor, and more particularly to a stepping motor that obtains an intermittent rotational output at a constant angle in both forward and reverse directions corresponding to an input pulse.

  Conventionally, stepping motors have features such as excellent low speed, high torque characteristics, variable speed control characteristics, positioning control characteristics, etc., and simple control circuits. Speed, rotation angle, forward / reverse rotation, start / stop Etc. are executed precisely. The stepping motor is suitably used for a drive mechanism of an electronic device such as a digitally controlled facsimile or printer.

  As shown in the sectional view of FIG. 4 and the exploded perspective view of FIG. 5, a conventional single layer PM (Permanent Magnet) stepping motor 41 includes a motor case 42, a lid 43, stators 45a and 45b, and coils. A stator structure 44 including a body 46, a terminal member 47, a rotor structure 48 including a magnet 49 and a rotating shaft 50, and a circuit board 51 are configured. The motor case 42 is formed in a bottomed cylindrical shape whose upper part is released by a metal material, and a shaft hole is provided at the center of the bottom surface portion 42 a to assemble the first bearing 52 a and a terminal opening 53 on the outer peripheral surface 42. Is formed. The motor case 42 constitutes a motor housing by assembling constituent members therein and closing an upper opening and assembling a lid 43. The lid body 43 is assembled with a second bearing 52b in a shaft hole provided in the center, and the first and second bearings 52a and 52b are in a state where the motor case 42 and the lid body 43 are assembled. , The axis lines match.

  The motor case 42 is supported on the bottom surface portion 42a and a stator structure 44 is accommodated in the internal space. The stator structure 44 is composed of a pair of upper and lower stators 45a and 45b made of iron plates or the like, and a coil body 46 sandwiched between them. Composed. As shown in FIG. 5, each of the stators 45a and 45b is a magnetic pole piece 54 in which a plurality of strip-like magnetic pole pieces located at the same circumference and at the same interval are vertically bent downward and upward. , 56 encloses the coil body 46, and a plurality of coils 59 are paired vertically inside the annular coil case body so as to be accommodated at positions opposed to the magnetic pole pieces 54, 56 to form a magnetic space 58. doing. The terminal members 47a and 47b are joined and fixed in the vicinity of the outer peripheral edges of the stators 45a and 45b. A large number of lands are formed on one surface of the terminal members 47a, 47b, and the leads 59a, 59b drawn from the coil body 46 are connected to the lands, and the stator structure 44 is placed in the motor case 42. In the assembled state, the projecting surface side of the opposite pin terminal faces outward from the outer peripheral surface of the motor case 42 via the terminal opening 53.

  In the rotor structure 48, a magnet 49 is rotatably accommodated in a magnetic space 58 of the stator structure 44. The magnet 49 made of a ferrite material or the like has N poles and S poles alternately magnetized on the outer peripheral surface. The rotor structure 48 is loaded in the upper opening magnetic space 58 of the motor case 42 in a state where the stator structure 44 is assembled in the motor case 42. Although not described in detail in the circuit board 51, a drive circuit is mounted, and a plurality of fitting holes 51a to which the pin terminals provided in the terminal members 47 are respectively fitted and electrically connected. , 51b are formed. The circuit board 51 is attached to the outer surface of the motor case 42 so as to close the terminal opening 53, so that each pin terminal of the opposing terminal member 47 is fitted into the fitting hole 51. As shown in FIG. 4, the terminal opening 53 is formed with notches 53a and 53b at the upper portion corresponding to the upper stator 45a so as to be wide on both sides. The gaps 61a and 61b are formed between both side edges of the circuit board 51 by 53b. The gaps 61 a and 61 b are configured as an adhesive filling portion that joins and fixes the stator structure 44 to the motor case 42. As described above, the adhesive filled from the gaps 61a and 61b penetrates in a substantially uniform state between the inner surface of the motor case 42 and the outer peripheral portion of the flange portion 55 by a capillary phenomenon to form an adhesive layer. As a result, the stator 45 is securely joined and fixed to the motor case 42.

  In such a stepping motor 41, input pulses are sequentially supplied to the coils 59 of the coil body 46 through the drive circuit of the circuit board 51. By supplying the input pulse, each coil 59 is sequentially shifted from the excited state to the demagnetized state, and the magnetic pole pieces 54 and 56 paired with each coil 59 are also sequentially switched from the excited state to the demagnetized state. In the stepping motor 41, a magnetic attractive force / repulsive force is generated between the magnetic pole pieces 54 and 56 and the magnetic pole of the magnet 59 of the rotor structure 58, and the magnet 59, in other words, the rotary shaft 50 is intermittently driven to rotate. .

  Since the motor case 42 and the stators 45a and 45b are firmly fixed by the adhesive as described above, the motor case 42 and the stators 45a and 45b collide even when the rotating shaft 50 is intermittently rotated. And the terminal member 47 does not collide with the terminal opening 53. Therefore, the generation of noise is greatly reduced, and stable intermittent rotation output can be obtained.

  Although the single-phase PM stepping motor as shown in FIGS. 4 and 5 has been described so far, a multi-layer PM stepping motor having a large number of stators can be similarly filled with an adhesive from each gap and joined.

FIG. 6 shows a multilayer PM stepping motor provided with an adhesive filling hole. Dust or the like enters the gap from the adhesive filling gap formed between the terminal opening and the circuit board. In order to avoid a situation in which the rotation of the rotor structure deteriorates or the internal vibration sound leaks from the gap to the outside and becomes a large noise, the terminal opening 74 is configured so that the circuit board 75 is completely closed. The stepping motor 70 is provided with a plurality of adhesive filling holes 76, 77, and 78 (each of a, b, and c, respectively) corresponding to each of the multilayer stator structures on the outer peripheral surface of the motor case 71. The stator structure and the motor case are joined together.
JP 2002-359960 A (pages 4 to 6, FIG. 1, FIG. 2, FIG. 5)

  However, in the above-described conventional example, the stepping motor 41 has the stator 45 having an outer diameter substantially equal to the inner diameter of the motor case 42, and the stator structure 44 is accommodated in the motor case in a so-called filling state. Depending on the dimensional accuracy of the stator 45, a gap may be formed between the inner surface and the outer peripheral portion. On the other hand, the magnet 49 having a relatively large mass of the rotor intermittently repeats the rotation / stop operation, thereby generating vibration. For this reason, the inner surface of the motor case 42 and the stator 45 may collide with each other, or the terminal members 47a and 47b may collide with the opening edge of the terminal opening 53 to generate an impact sound. The conventional stepping motor prevents noise by joining the outer peripheral surface of the stator 45 to the inner surface of the motor case 42 with an adhesive. In this case, the joining process is performed by applying an adhesive in advance over the entire outer periphery of the stator 45 and storing the stator 45 in the motor case 42 in this state. In this case, since the inner diameter and the outer diameter of the motor case 42 and the stator 45 are substantially equal, the adhesive is stretched by the inner surface of the motor case 42 and a sufficient amount of the adhesive remains on the outer peripheral portion of the stator 45 at a predetermined position. In a state where the stator 45 is not housed or in a state where the stator 45 is housed in a predetermined position of the motor case 42, the amount of adhesive applied is not uniform over the entire circumferential direction. there were. Furthermore, when a large amount of adhesive is used, a part of the adhesive adheres to the outer peripheral surface of the magnet 49 and the magnetic characteristics deteriorate, or a part of the adhesive adheres to the bearings 52a and 52b. Inconveniences such as the possibility of occurrence occurred.

  In order to improve this, in the prior art, as shown in FIGS. 4, 5, and 6, as shown in FIGS. Although uniform application was attempted using the capillary phenomenon, the malfunction caused by adhesion of the adhesive to the magnet 49 and the rotating shaft 50 due to the use of a large amount of adhesive can be improved by changing the method of filling the adhesive. However, the disadvantage that a sufficient amount of adhesive does not remain on the outer peripheral surface of the stator 45 and that the amount of applied adhesive is not uniform over the entire circumferential area are completely improved. In addition, since the adhesive strength is likely to vary, there is a problem that uniform adhesion and fixing becomes difficult and noise generation cannot be suppressed.

  In addition, there is a problem that the number of work steps is increased in the bonding process using the adhesive.

  Therefore, there is a technical problem to be solved in order to obtain a stepping motor capable of fixing a stable stator and motor case that can reduce variation in characteristics by a simple process without adopting fixing by an adhesive. The present invention aims to solve this problem.

  The present invention has been proposed in order to achieve the above object, and the invention according to claim 1 is a substantially cylindrical motor case having one end closed, and the opening of the motor case is closed and assembled. And a stator having an outer diameter substantially equal to the inner diameter of the motor case and forming a large number of magnetic pole pieces along the inner peripheral edge, and embedded in the motor case, and coils corresponding to the magnetic pole pieces And a stator structure comprising a coil body that sequentially excites the magnetic pole pieces, and the stator structure is connected to each coil and is exposed outward from a terminal opening formed in the motor case. Are rotatably housed in a magnetic space formed by a terminal member assembled to each of the magnetic pole pieces of the stator, and intermittently driven to rotate by a magnetic force generated between the magnetic pole pieces. A rotor structure composed of a rotating body and an output shaft, and a circuit board that is assembled to a terminal opening of the motor case and connected to the terminal member, and supplies an input pulse to each coil, A caulking portion is formed at a position of an outer peripheral surface of the motor case corresponding to a notch formed in an outer peripheral edge of the stator, and the outer peripheral surface of the stator and the inner peripheral surface of the motor case are fixed by caulking. Yes.

  The invention according to claim 2 is characterized in that the caulking position is set to two or more points based on two opposing points.

  The invention according to claim 3 is characterized in that the notch uses an adjustment notch formed on an outer peripheral edge of each stator.

  The invention described in claim 4 is characterized in that the stepping motor is a stepping motor having a single layer or two or more layers.

  According to this stepping motor, the motor case and the stator are fixed from the fixing method by filling the adhesive, and the crimping portion and the notch portion are formed on the outer peripheral surface, and then the crimping and fixing method is performed by a simple mechanical method using the crimping. In other words, the caulking position is also performed at two or more points facing each other on the outer peripheral surface, so that the bias can be eliminated, the process can be reduced, and the motor case and the stator can be fixed uniformly and stably by a simple operation.

  According to the invention of claim 1, compared to the gap between the terminal opening and the terminal substrate in the prior art, and a method of diffusing using a capillary phenomenon by filling an adhesive from an adhesive filling hole, In order to fix the caulking part of the motor case and the notch part of the stator structure by a simple mechanical method, the motor case and the stator structure can be fixed uniformly to generate noise such as vibration noise. There is an effect that it can be suppressed.

  Furthermore, the work is simpler than the complicated adhesive filling process, the process can be reduced, and the yield is improved.

  Further, according to the invention described in claim 2, since the crimping position is set to two or more points, in addition to the effect of the invention described in claim 1, since it can be fixed uniformly without deviation, noise such as vibration noise can be prevented. There is an effect that the occurrence can be suppressed.

  According to the invention described in claim 3, since the notch uses an existing notch, in addition to the effect of the invention described in claim 1 or 2, the cost can be reduced.

  According to the invention of claim 4, in addition to the effect of the invention of claim 1 or 3, there is an effect that it can be widely applied to various motors from a single layer type stepping motor to a multilayer type stepping motor.

  Embodiments of the present invention will be described below with reference to FIGS.

  FIG. 1 is an external perspective view of a stepping motor according to an embodiment of the present invention.

  FIG. 2 is a process explanatory diagram of the stepping motor shown in FIG.

  In FIG. 1, a stepping motor 1 is a single-layer PM type stepping motor, and includes a motor case 2 and crimping portions 12 a and 12 b (to be described at two or more places) to be processed on the outer peripheral surface of the motor case 2. A terminal opening 11 opened in the motor case 2, terminal members 7a and 7b connected to the coil of the stator structure 4 facing outward from the terminal opening 11, a bracket (lid part) 3, a rotor A rotating shaft 10 for housing and fixing (not shown) in the magnetic space of the stator, and a bearing bush 20a for locking upper and lower bearings (not shown) for fixing the rotating shaft 10 to the motor case 2; Consists of. In the figure, reference numeral 22 denotes a mounting hole for a substrate or chassis.

  Next, a fixing process by caulking of the motor case and the stator of the stepping motor configured as described above will be described with reference to FIG.

  First, as shown in FIG. 2A, as a pre-processing stage, in the circumferential direction, at a position corresponding to a notch 13 of the stator 5 (details of the position will be described later) near the center of the outer peripheral surface of the motor case 2. When the stator portion 5 is housed in the motor case 2, as shown in FIG. 2 (b), the long narrow rectangular crimping portion 11 is punched by press working, and the notches 13a and 13b of the motor case 2 stator 5 are formed. And the crimping portions 12a and 12b are formed and both are fixed.

  After the positioning of the caulking portions 12a, 12b and the notch portion 13 is completed, the caulking portions 12a, 12b are squeezed into the notch portions 13a, 13b with a caulking punch in the pressing process as shown in FIG. The motor case 2 and the stator 4 are fixed and crimped by caulking.

  Thus, in FIG. 1, the caulking portions 12a and 12b are formed at two opposing locations, but the present invention should not be limited to this, and a large number may be provided. In that case, fixing by caulking is further stabilized. For example, when the caulking portion is set at one place, the deviation occurs and the distance between the motor case 2 and the inscribed stator 4 varies, which causes generation of vibration noise and impact noise. Thus, the caulking portion must be provided at a plurality of locations.

  Next, the entire process will be described with reference to FIG.

  FIG. 3 is an exploded perspective view of the stepping motor shown in FIG. 1. The motor case 2 is a bracket in which the upper opening is closed after each component member, the stator structure 4, the rotor structure 8 and the like are assembled therein. 3 is assembled to constitute a motor housing. On the outer peripheral surface of the motor case 2, two or more crimping portions (crimping pieces) 12a and 12b for punching are punched.

  In the motor case 2, the stator structure 4 is accommodated in the internal space supported by the bottom surface portion. The stator structure 4 includes a pair of upper and lower stators 5 a and 5 b and a coil body 6. Cutout portions 13 a, 13 b, 13 c, 13 d... Used for positioning adjustment are formed at positions facing the outer peripheral edge of the stator 5 at approximately 180 °. The terminal members 7a and 7b are joined and fixed in the vicinity of the outer peripheral edge of each stator 5, and are fixed to the respective stators 5a and 5b so that the upper side surfaces from which the pin terminals protrude are protruded from the outer peripheral edge. Has been. The lead wire of the coil body 6 is connected to the opposite side, and the pin terminal faces outward from the terminal opening 11 in a state where the stator structure 4 is housed in the motor case.

  In this state, when the stator structure 4 is accommodated in the motor case 2, the crimping pieces 12a and 12b of the motor case 2 and the notch 13 (13a, 13b or 13c, 13d) of the stator structure 4 are positioned, The motor case 2 and the stator structure 4 are crimped and fixed by caulking.

  Subsequently, the magnet 9 constituting the rotor structure 8 is attached to the attached upper and lower bearing bushes 20 a and 20 b and is rotatably accommodated in the magnetic space portion of the stator structure 4. Thus, the PM type stepping motor 1 as shown in FIG. 1 is completed.

  As described above, in the present invention, the conventional fixing method in which the adhesive is filled from the gap of the terminal opening or the adhesive filling hole is fixed by caulking at two or more locations. However, in the case of an adhesive, it is necessary to control the position of the filling port of the adhesive, the amount of filling, etc., and the number of man-hours is increased. The work can be fixed securely. In addition, since existing adjustment cutouts can be used, the cost can be reduced.

  Heretofore, the single-layer PM type stepping motor shown in FIG. 1 has been described. However, the present invention is not limited to this, and the multi-layer type stepping motor shown in FIG. Use two notch portions on both sides of the center stator to fix the two locations, or use both notch portions of the uppermost stator of the terminal member 73a and the lowermost stator of the terminal member 73c. It can be fixed in place, or it can be fixed in three places by using both sides of the central stator and one notch in the upper or lower stator. By doing so, it can be simply and stably fixed as in the case of a single layer. Further, even if the multi-layer configuration is increased beyond that of the stepping motor shown in FIG.

1 is an external perspective view of a stepping motor according to an embodiment of the present invention. Process explanatory drawing of the stepping motor shown in FIG. The disassembled perspective view of the stepping motor shown in FIG. Sectional drawing of the conventional stepping motor. FIG. 5 is an exploded perspective view of the stepping motor shown in FIG. 4. Sectional drawing of the conventional multilayer type stepping motor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 PM type stepping motor 2 Motor case 3 Bracket 4 Stator structure 5 Stator 6 Coil body 7 Terminal member 8 Rotor structure 9 Magnet 10 Rotating shaft 11 Terminal opening part 12 Crimp part 13 Notch part 20 Bearing bush 22 Mounting part

Claims (4)

  A substantially cylindrical motor case with one end closed, a lid that is assembled by closing the opening of the motor case, an outer diameter that is substantially equal to the inner diameter of the motor case, and a large number along the inner periphery A stator structure comprising a stator that forms magnetic pole pieces and is housed inside the motor case, a coil body in which coils corresponding to the magnetic pole pieces are arranged and sequentially excites the magnetic pole pieces, and the coils are connected. And a terminal member that faces outward from a terminal opening formed in the motor case and is assembled to the stator structure, and is freely rotatable in a magnetic space formed by the magnetic pole pieces of the stator. A rotor structure comprising a rotating body and an output shaft that are housed and intermittently driven to rotate by a magnetic force generated between the magnetic pole pieces, and a terminal opening of the motor case And a circuit board for supplying an input pulse to each of the coils, wherein the motor case corresponds to a notch formed in the outer periphery of the stator. A stepping motor characterized in that a caulking portion is formed at a position of the outer peripheral surface of the stator, and the outer peripheral surface of the stator and the inner peripheral surface of the motor case are fixed by caulking.   The stepping motor according to claim 1, wherein the caulking position is set to two or more points based on two opposing points.   The stepping motor according to claim 1, wherein the notch uses an adjustment notch formed on an outer peripheral edge of each stator. The stepping motor according to any one of claims 1 to 3, wherein the stepping motor is a stepping motor having a single layer or two or more layers.

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