JP6097538B2 - Stepper motor rotor structure - Google Patents

Description

  The present invention belongs to the technical field of stepping motors mounted on various OA devices, home appliances, and the like, and particularly relates to a rotor structure.

  Conventionally, as a rotor structure of a PM type (permanent magnet type) stepping motor, cylindrical permanent magnets in which SN poles are alternately and circumferentially magnetized are arranged around the outer periphery of a disk body, and a plurality of these are face-to-face. There is a configuration in which the rotary shaft is circularly arranged at predetermined intervals (see, for example, Patent Document 1).

  As described above, the reason why the cylindrical permanent magnets are circularly arranged on the rotating shaft with a predetermined interval is that, as described in Patent Document 1, non-magnetized regions with a predetermined interval are arranged in the axial direction of the permanent magnet. This is to prevent magnetic interference between the stators arranged opposite to the magnetic poles of the permanent magnets, and to suppress torque variation and unevenness.

  In addition, a rotor structure having a configuration for holding a plurality of cylindrical permanent magnets and ensuring rigidity to prevent cracks due to thermal expansion of the permanent magnets has also been disclosed. For example, in the rotor structure of Patent Document 2, a so-called rotor collar that holds a permanent magnet is formed in a cylindrical shape from a resin material and is mounted on a rotating shaft, and both ends of the rotor collar are mounted on the rotating shaft. The cylindrical permanent magnets are arranged at predetermined intervals on the outer periphery of the disc.

  In addition, after arranging a plurality of cylindrical permanent magnets in the molding die and a rotating shaft in the center of the shaft in advance, the molding resin is filled and a plurality of permanent magnets, the rotating shaft, and the rotor collar are integrally formed. A rotor structure having such a configuration has also been disclosed (see, for example, Patent Documents 3 and 4).

JP-A-10-84663 JP 2002-51525 A JP-A-6-245473 Japanese Patent Laid-Open No. 11-299148

  The rotor structure disclosed in the above-mentioned Patent Document 1 has a configuration in which a space between permanent magnets is simply used as a space in order to secure a non-magnetized region, or a cylindrical member made of a nonmagnetic material is inserted into this space. It was. In the case where the air gap is merely a gap, abnormal noise was generated due to the turbulence of the air flow in the air gap during the rotation of the rotor. This abnormal noise is caused by vibration at a predetermined frequency, and is also a cause of noise of the entire stepping motor.

  On the other hand, in the case of a configuration in which a cylindrical member is simply interposed in the gap, in order to fix the cylindrical member and the permanent magnet, a process of bonding or press-fitting both of them is required, and there is a problem that the assembly becomes complicated. It was. In addition, if the cylindrical member is simply held with a permanent magnet without adhesion or the like, there is a risk of displacement between the cylindrical member and the rotor collar during the rotation of the rotor, or it may fall off the rotor. It was a cause of noise and malfunction.

  In the rotor structure of Patent Document 2, the rotor collar is formed in a cylindrical shape from a resin material. However, in order to ensure the rigidity to rotate while holding a plurality of permanent magnets, the height of the cylindrical portion only increases. Instead, it was necessary to form a thick rib. Since such a rotor structure is heavy, inertia (rotational moment of inertia) increases, and there is a problem that motor characteristics are deteriorated.

  In the rotor structures disclosed in Patent Documents 3 and 4, cracks are generated on the permanent magnet side due to the difference in thermal expansion coefficient between the permanent magnet and the resin rotor collar, and the holding force by the resin at the time of integral molding is increased by using the rotor for a long time. There was a risk that the permanent magnets would be displaced and fall off. In addition, since this rotor structure is integrally formed by arranging a plurality of resin-made rotor collars and permanent magnets, it is necessary to prepare in advance a mold having a high dimensional accuracy requirement, and the cost is high.

  Accordingly, the present invention has been made paying attention to the above-mentioned problems, and at least partially covers the outer peripheral open surface of the space between the permanent magnets of the rotor with a structure that is simple and easy to assemble, and this covered state is stable. The rotor structure of the stepping motor that can be maintained in the above is provided.

  In order to solve the above problems, the rotor structure of the stepping motor according to the present invention is configured as follows.

That is, the rotor structure includes a rotating shaft, a disk-shaped rotor collar that is mounted around the center of the rotating shaft and held vertically, and is fitted on and held by the rotor collar. A cylindrical permanent magnet formed by continuously forming a magnetic domain in the circumferential direction, and a structure of the permanent magnet and the rotor collar are mounted on the rotating shaft in a face-to-face manner with a predetermined separation distance. And a cover body that covers at least a part of the outer peripheral open surface of the space formed by the above structure , and the cover body includes an urging means that extends in the axial direction of the rotary shaft .

  The cover body may be in a form that covers at least a part of the outer peripheral open surface formed between the constituent body of the permanent magnet and the rotor collar (hereinafter referred to as “rotor constituent body”). A curved plate obtained by vertically dividing a cylindrical body covering a part of the surface into four parts, or a partially cut-out cylindrical body having a C shape when viewed from above may be used. Of course, it is good also as a form which obstruct | occludes an outer peripheral open | release surface by forming in a thin thin cylinder body with a hollow inside. And in order to make a cover body lighter, you may provide a 1 or several opening in a side surface. In addition, in order to avoid interference on the stator side of the stepping motor, the outer shape portion of the cover body needs to be set so as not to protrude outward from the position of the outer peripheral surface of the permanent magnet.

Further, a specific example configuration of the biasing means of the cover body, a curved cover body as described above plate, partially cut-away cylinder, and in the case of forming a normal cylinder, the end surface A tongue piece that can be elastically deformed is formed to extend outward in the axial direction. And when arrange | positioning between rotor structural bodies, the form which makes the front-end | tip side of the said tongue piece part contact | abut to the plane part of a rotor collar and to elastically deform is mentioned. Alternatively, the entire cover body may be made of an elastic material, and the cover body may be sandwiched while being elastically deformed by the front and rear rotor constituent bodies.

  In addition, the energizing means of the cover body is formed with an engaging means for the rotor collar and the rotating shaft, for example, a curved portion that fits and abuts a part of the rotor collar and a part of the rotating shaft. May be.

The present invention configured as described above has the following technical effects.
That is, by covering at least a part of the outer peripheral open surface between the rotating rotor structural members with the cover body, the disturbance of the air flow generated in this space is suppressed, and as a result, vibration at a predetermined frequency and Occurrence of abnormal noise accompanying this can be suppressed.

  In addition, the cover body is lightweight because it is formed of the curved plate, a partially cut-out cylindrical body, and a thin-walled cylindrical body, and even if this cover body is simply added to the existing rotor structure, The increase in inertia can be suppressed as compared with the rotor, and the performance of the stepping motor is not deteriorated.

  Furthermore, since the cover body includes an urging means, when it is disposed at a predetermined position so as to cover at least a part of the outer peripheral open surface, the integrity of the rotor structure and the other components of the rotating shaft is improved, Even during rotation, the covered state can be stably maintained without being displaced or the cover itself falling off from the rotor itself, which can contribute to maintaining the performance of the stepping motor.

It is an assembly perspective view of the stepping motor which has a rotor structure of a present Example. It is an assembly perspective view of the rotor which has the rotor structure of a present Example. It is a longitudinal cross-sectional view of the rotor which has a rotor structure of a present Example. It is a perspective view (A), (B), (C) which shows the modification of the cover body of a present Example. It is the side view (A) and top view (B) which show the modification of the biasing means of the cover body of a present Example. It is a graph which shows the relationship between the frequency (pps) and vibration (m / s < ² >) which compared the stepping motor of the rotor structure of a present Example with the stepping motor of the conventional rotor structure.

  Hereinafter, the best embodiment of the rotor structure of the stepping motor of the present invention will be described with reference to the drawings.

  Reference numeral 1 denotes a stepping motor (hereinafter abbreviated as “motor”). In the motor 1 of this embodiment, as shown in the assembly perspective view of FIG. 1, a cylindrical stator 4 is disposed inside a low and low cylindrical motor case 2, and a rotor 5 is placed in a central internal space 43 of the stator 4. Is configured to be rotatable, and the open side of the motor case 2 is closed by the motor cover 3.

  A part of the rotating shaft 54 of the rotor 5 projects from the bottom side of the motor case 2 to form an output portion 54a. Further, a flange 23 for mounting the motor case 2 on other OA equipment, home appliances, etc. is arranged on the bottom 21 of the motor case 2.

  The stator 4 has a two-layer structure in which yokes 41 having a substantially cylindrical shape are stacked in two layers in the thickness direction, and has a cylindrical shape having a central internal space 43 as a whole. Each of the yokes 41, 41 is configured by arranging magnetic poles 41a formed so as to alternately engage with each other at a predetermined number and a predetermined pitch at the inner peripheral position, and winding a coil 42 around the outer peripheral portion. . The coil 42 of the yoke 41 is connected to a predetermined power source (not shown) and a control device (not shown), and is appropriately supplied with current.

  Since the basic configuration of the motor 1 and the stator 4 is the same as that of the prior art, further detailed description is omitted.

Next, the rotor 5 according to the rotor structure which is the main point of the present invention will be described.
The rotor 5 is axially supported by the bearings 22 and 31 disposed in the motor case 2 and the motor cover 3 and is rotatably disposed in the central internal space 43 of the stator 4.

  The rotor 5 includes a rotor structure 51 formed by externally holding a cylindrical permanent magnet 53 on a disk-shaped rotor collar 52 (hereinafter abbreviated as “color”), and two rotor structures 51. The rotating shaft 54 coaxially arranged with a predetermined separation distance so that the flat surface portion 52a of the collar 52 faces, and the cover body arranged so as to close the outer peripheral open surface of the space formed by the facing arrangement of the rotor constituting body 51. 6.

  The collar 52, which is a constituent element of the rotor structure 51, is formed in a disc shape from a thin and light plated steel plate, and a fitting port 52b that fits the rotating shaft 54 is formed at the center of the flat portion 52a. Further, a thick boss portion 52c is formed around the fitting port 52b of the flat portion 52a on one side in order to improve the rigidity of the collar 52. The material of the collar 52 is not limited to the plated steel plate, but may be other metal material such as aluminum or synthetic resin material such as plastic as long as rigidity can be ensured.

  The permanent magnet 53, which is externally fitted and fixed to the outer periphery of the collar 52, has a cylindrical shape in which the SN pole magnetized regions are alternately formed in the circumferential direction and continuously at a predetermined pitch on the outer peripheral surface 53a. The height dimension is longer than the thickness dimension. Further, when the outer peripheral surfaces 53a of the two-stage permanent magnets 53 arranged on the rotating shaft 54 are arranged in the central inner space 43 of the stator 4, the arrangement of the magnetic poles 41a and 41a of the two-layered yoke 41 is provided. It faces the surface with a predetermined gap.

  As described above, the rotating shaft 54 fixes the above-described two rotor constituent bodies 51 in a face-to-face manner and coaxially with a predetermined separation distance. Further, the rotating shaft 54 is rotatably supported by bearings 22 and 31 disposed on both ends of the motor case 2 and the motor cover 3 and protrudes outward from the flange 23 on the motor case side to form an output portion 54a. Yes.

  The cover body 6 is formed of a thin-walled main body portion 61 having a substantially cylindrical shape from a synthetic resin material, and an outer periphery of a space formed by a separation distance of the rotor structure body 51 arranged in two stages on the rotary shaft 54 as described above. It arrange | positions so that an open surface may be obstruct | occluded. In the present embodiment, the outer peripheral surface 61 a of the main body 61 is brought close to or in contact with the inner peripheral surface 53 b of the permanent magnet 53, and one end surface 61 b is brought into contact with the flat portion 52 a of the collar 52 to thereby close the closed state. It is made.

  Further, the cover body 6 extends in the axial direction of the rotating shaft 54 (a direction parallel to the axial extension direction of the rotating shaft), in other words, a tongue piece that elastically deforms with an urging force in both directions of the rotor constituting body 51. 62. The tongue 62 extends from the end surface 61b on one side to the axial center and to the outside in the axial direction, and forms a curved portion 62a that avoids interference with the outer periphery of the boss 52c of the collar 52 at the tip. doing.

  Since the tongue piece 62 has the property of elastically deforming in the axial direction as described above, it exerts an urging force that expands in the axial direction when arranged in the space formed by the rotor structure 51 (arrow f). . As a result, the cover body 6 has improved integrity with the rotor constituting body 51 disposed in the front and rear in the axial direction.

  The curved portion 62a may be formed in a shape that follows the outer peripheral portion of the boss portion 52c. In this case, a part of the curved portion 62a contacts or engages with the outer peripheral portion of the boss portion 52c during elastic deformation.

  Further, the cover body 6 may be set to an outer dimension in which the outer peripheral surface 61 a coincides with the outer peripheral surface 53 a of the permanent magnet 53 as long as the outer peripheral open surface of the space can be closed. However, since the outer peripheral surface 53 a of the permanent magnet 53 is opposed to the inner peripheral surface of the central internal space 43 of the stator 4 and the magnetic pole 41 a with a predetermined gap, the outer peripheral surface 61 a of the cover body 6 is opposed to the outer peripheral surface 53 a of the permanent magnet 53. It is desirable to set so as not to protrude outward.

The rotor 5 having the above configuration is assembled and configured in the following steps.
First, the permanent magnet 53 is fitted on the outer periphery of the collar 52 and fixed to form a total of two rotor components 51.

  Next, one rotor structure 51 is fixed by attaching the fitting port 52 b of the collar 52 to the rotary shaft 54. In this case, the rotating shaft 54 is mounted so that the boss portions 52c of the collar 52 of the other rotor constituting body 51 face each other.

  Then, the main body 61 of the cover body 6 is mounted on the rotating shaft 54. The height dimension of the main body 61 is set in accordance with the separation distance of the rotor constituting body 51. When the main body 61 is mounted, the outer peripheral surface 61 a of the main body 61 of the cover body 6 is used as the inner peripheral surface 53 b of the permanent magnet 53 while avoiding interference between the boss 52 c of the collar 52 and the tip of the tongue piece 62. Keep along.

  Finally, while fixing the collar 52 of the other rotor constituting body 51 to the rotating shaft 54, similarly, the inner peripheral surface 53b of the permanent magnet 53 is fixed along the outer peripheral surface 61a of the main body 61 of the cover body 6. To do. At this time, both end surfaces 61a and 61a of the cover body 6 are sandwiched between the two rotor constituent bodies 51 while ensuring a predetermined separation distance.

  Due to the positional relationship between the rotor structure 51 and the cover body 6 and the assembly process, the tongue piece portion 62 of the cover body 6 sandwiched between the rotor structure 51 and the flat portion 52a of the collar 52 of the rotor structure 51 is formed. The rotor 5 that exerts an urging force that expands in the axial direction of the rotary shaft 54 in order to abut against the rotor shaft (arrow f), and the integrity of the two rotor constituent bodies 51 having a predetermined separation distance and the cover body 6 is improved. Will be assembled.

  Although the cover body 6 in the above-described embodiment closes the outer peripheral open surface formed by the rotor constituting body 51 using the main body 61 as a cylindrical body, it is not limited to this form. That is, as shown in FIG. 4, a curved plate-like main body 61 obtained by vertically dividing the cylindrical body into four parts so as to cover a part of the outer peripheral open surface, and a partially cut-out cylindrical body that is C-shaped when viewed from above. The main body 61 can also be used. Furthermore, a plurality of apertures 63 can be formed in the main body 61 in order to reduce the weight of the cover body 61. As the shape of the opening 63, an appropriate shape such as a rectangle, a polygon, an ellipse, or a circle can be adopted. Moreover, it is preferable that the area of the curved plate-like main body 61 and the size, position, and number of the openings 63 of the main body 61 are set while actually measuring vibration due to air flow disturbance.

  The tongue piece 62 is not limited to the present embodiment, and may be disposed on both end faces 61b and 61b of the main body 61 as shown in FIG. You may arrange | position to a circumference equally.

The frequency (pps, pulse parsec) and vibration (m / s ² ) of the motor of the present rotor structure in which the cylindrical cover body according to the above embodiment is arranged and the motor of the conventional rotor structure that differs only in the arrangement of the cover body. ) Was measured and the graph shown in FIG. 6 was obtained.

  That is, in the conventional rotor structure motor, a relatively large vibration peak value was measured at specific frequencies (1700 pps and 3100 pps). This vibration is caused by the turbulence of the air flow in the gap between the permanent magnets during the rotation of the motor, and causes the generation of abnormal noise.

  On the other hand, it was confirmed that the motor of the rotor structure of the present application has a relatively flat vibration even when the frequency is increased or decreased, and exhibits a technical effect due to the arrangement of the cover body.

DESCRIPTION OF SYMBOLS 1 Motor 2 Motor case 21 Bottom part 22 Bearing 23 Flange 3 Motor cover 31 Bearing 4 Stator 41 Yoke 41a Magnetic pole 42 Coil 43 Central internal space 5 Rotor 51 Rotor structure 52 Collar 52a Plane part 52b Fitting part 52c Boss part 53 Permanent magnet 53a Outer circumference Surface 53b Inner peripheral surface 54 Rotating shaft 54a Output portion 6 Cover body 61 Main body portion 61a Outer peripheral surface 61b End surface 62 Tongue piece portion 62a Bending portion 63 Opening

Claims (4)

A rotating shaft;
A disc-shaped rotor collar which is mounted around the center of the rotating shaft and held vertically;
A cylindrical permanent magnet that is externally fitted to the rotor collar and held, and alternately formed with different polar magnetization regions continuously in the circumferential direction;
A cover body that covers the rotating magnet in a face-to-face configuration with a predetermined separation distance, and covers at least a part of the outer peripheral open surface of the space formed by the face-to-face arrangement;
Ri consists of,
A rotor structure of a stepping motor, wherein the cover body includes an urging means that extends in an axial direction of the rotating shaft . 2. The rotor structure of a stepping motor according to claim 1, wherein the urging means of the cover body includes means for engaging with the rotating shaft or the rotor collar. 3. The rotor structure of a stepping motor according to claim 1, wherein the cover body is formed in a cylindrical body that closes the outer peripheral open surface. 4. The rotor structure of a stepping motor according to claim 1, wherein one or a plurality of apertures are formed in a side surface portion of the cover body.

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