JP6265879B2 - Damper and stepping motor using the same - Google Patents

Description

  The present invention relates to a damper attached to a stepping motor and a stepping motor attached with the damper.

  Since the rotor rotates while the vibration of the stepping motor is attenuated with respect to the input drive pulse, if the natural frequency of the rotor matches the frequency of the drive pulse, the rotation becomes impossible and the output torque becomes unstable due to resonance. In order to cope with this, it is known to attach a damper such as an inertia load to the shaft. In such a stepping motor in which a damper is attached to a shaft, a stepping motor in which a damper is built in the motor to reduce the thickness of the motor has been proposed (for example, see Patent Document 1).

  A step motor 100 described in Patent Document 1 shown in FIG. 8 includes a first rotor yoke 113 and a first rotor yoke 113 that are rotatably supported by upper and lower bearing portions 109 and 110 and that have a disk shape at substantially the center of the rotation shaft 112. A second rotor yoke 114 is provided, and a rotor 116 in which a magnet 115 is provided between the rotor yokes 113 and 114 is provided. A damper wheel 119 is provided between the upper bearing portion 109 and the rotor yoke 113 in the drawing. In the damper wheel 119, an intermediate body 119b and an external roll 119c made of an elastic body such as rubber are mounted on the outer periphery of a mounting base 119a fixed to the rotating shaft 112.

Japanese Utility Model Publication No. 63-4180

  An elastic portion (intermediate body 119b) such as rubber is interposed between a sleeve (mounting base portion 119a) fixed to the rotating shaft and a weight (external roll 119c), such as the damper wheel described in Patent Document 1. The damper is generally manufactured by performing vulcanization adhesion in which an elastic portion is vulcanized and bonded between a sleeve and a weight. That is, in order to obtain such a damper, a vulcanization bonding process is required in which an elastic portion made of an elastic body such as rubber is formed and vulcanized and bonded to the sleeve and the weight. There is a problem of causing a decline in sex. Further, due to the difference in thermal expansion coefficient between the elastic part and the weight, there is a possibility that the elastic part may be peeled off from the weight when the elastic part contracts during cooling, resulting in a problem that the adhesive strength is lowered.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a damper capable of improving productivity and improving the bonding strength of an elastic portion to a weight, and a stepping motor using the same. .

The damper of the present invention is a damper having a sleeve fixed to the outer periphery of the shaft, and an annular weight provided on the outer peripheral portion of the sleeve via an elastic portion, and the elastic portion includes the sleeve and the sleeve. molded by filling between the weight, the way DOO has a pawl portion which engages the mold the elastic portion in the elastic portion, the claw portion is bent on one side in the axial direction Provided with a protrusion and provided at a plurality of circumferentially equally spaced portions of the inner periphery of the weight, the two weights facing each other, and the protrusion facing each other and the other claw between the weights of the other The weight of the claw portion is overlapped so as to enter (claim 1).

The damper of the present invention is a damper having a sleeve fixed to the outer periphery of the shaft and a weight provided on the outer peripheral portion of the sleeve via an elastic portion, and the elastic portion includes the sleeve and the sleeve. molded by filling between the weights engage wound around the outer circumference of the weight over the upper surface portion and lower surface portion exposed to one axial end and the other end in between said sleeve said weight said It has a several band part which presses an outer peripheral part to an inner peripheral side (Claim 2). This damper includes a form in which a linear cut portion that engages with the band portion is formed on the outer peripheral edge of the weight (claim 3).

The damper according to claim 2 or 3 includes a form in which a plurality of the weights are stacked (claim 4). Further, it includes a form in which a plurality of protrusions are formed on both end surfaces in the axial direction of the elastic portion.

  Next, a stepping motor according to the present invention includes a rotor including a shaft, a stator disposed to face the rotor, and the damper according to any one of claims 1 to 5.

  According to the damper of the present invention, by simply filling and molding the elastic portion, the labor of the process is reduced and the productivity is improved. Moreover, the joint strength of the elastic part with respect to the weight can be improved by the claw part of the weight engaging with the elastic part or the band part of the elastic part engaging with the weight.

1 is a cross-sectional view of a two-phase HB type stepping motor according to a first embodiment of the present invention. It is a top view of the stepping motor. It is a perspective view of the damper of a 1st embodiment which the stepping motor comprises. It is the (a) top view of the damper, (b) longitudinal section, and (c) bottom view. It is a perspective view of the weight of the damper. It is a perspective view of the damper concerning a 2nd embodiment of the present invention. It is a graph which shows the result of an Example. It is sectional drawing which shows the step motor of the past (patent document 1 description).

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[1] First Embodiment [1-1] Configuration of Stepping Motor FIG. 1 is a cross-sectional view of a two-phase HB type stepping motor 1 incorporating a damper 20 according to the first embodiment, and FIG. It is a top view. The stepping motor 1 includes a stator 2, a rotor 3, a front bracket 4, an end bracket 5, and a damper 20.

  The stator 2 includes a stator core 6 and a coil 8 wound around the stator core 6 via an insulator 7. The stator core 6 is configured by laminating a predetermined number of cores made of soft magnetic steel plates in the axial direction. The core has a plurality of salient poles extending radially inward from an annular yoke as a main body, and is a generally known core in which a plurality of small teeth are formed at the tip of each salient pole. Insulators 7 are mounted on the stator core 6 formed by stacking such cores from both sides in the axial direction, and coils 8 are wound around the salient poles via the insulators 7.

  A front bracket 4 and an end bracket 5 are respectively disposed on both sides in the axial direction of the stator 2 (up and down in FIG. 1). Bearings 15 and 16 are mounted at the centers of the brackets 4 and 5, respectively, and the shaft 14 of the rotor 3 is mounted through the bearings 15 and 16. As shown in FIG. 2, the front bracket 4 and the end bracket 5 are fixed to a state in which the stator core 6 is sandwiched by fastening fastening materials 35 such as bolts passed through four corner portions to the stator core 6. The shaft 14 is rotatably supported by the brackets 4 and 5 via bearings 15 and 16.

  The rotor 3 includes a rotor core 10, a magnet 13 and a shaft 14. The rotor core 10 includes a first rotor core 11 and a second rotor core 12, and a disc-shaped magnet 13 that is magnetized in two poles in the axial direction is disposed between the rotor cores 11 and 12.

  The first rotor core 11 and the second rotor core 12 are each configured by laminating a predetermined number of cores made of soft magnetic steel plates in the axial direction. The core is disk-shaped, has a hole through which the shaft 14 is inserted, and small teeth are formed at an equal pitch over the entire outer periphery. In each of the rotor cores 11 and 12, the small teeth are arranged with a 1/2 pitch shift, and thus the stepping motor 1 has a two-phase HB type stepping motor structure. A damper 20 is disposed between the first rotor core 11 and the front bracket 4.

  3 and 4 are views showing the damper 20, wherein FIG. 3 is a perspective view, FIG. 4 (a) is a plan view, FIG. 4 (b) is a longitudinal sectional view, and FIG. 4 (c) is a bottom view. . The damper 20 includes a hollow cylindrical sleeve 21 made of metal (for example, an aluminum alloy), an elastic portion 22 made of a rubber material (for example, silicon rubber), and a plurality of weights 23 made of metal (for example, an iron plate). It is configured.

  The sleeve 21 is fixed to the shaft 14 by press-fitting the shaft 14. A plurality of (in this case, two) weights 23 in the form of an annular plate are fixed to the outer periphery of the sleeve 21 via elastic portions 22. As shown in FIG. 5, the weight 23 is mainly composed of a circular ring portion 24 whose outer peripheral edge and inner peripheral edge are both circular, and protrudes radially inward from the inner peripheral edge of the circular ring portion 24, and then extends in the axial direction. The nail | claw part 25 bent and protruded to the one side is formed in the multiple places (in this case, 3 places) which equally divide the circumferential direction. The weight 23 is manufactured by, for example, a method in which an iron plate is formed by punching into a predetermined shape by pressing, and then the claw portion 25 is formed by bending in the axial direction.

  The two weights 23 are arranged so that the protruding directions of the respective claw portions 25 face each other, and are shifted so that the claw portions 25 of the other weight 23 enter between the claw portions 25 of the one weight 23. Are stacked and stacked. The sleeves 21 are concentrically arranged inside the two weights 23 laminated in this manner, and this state is held by the elastic portion 22 filled between the two weights 23 and the sleeve 21. . The elastic portion 22 is filled between the inner peripheral edge portion of the annular portion 24 of the two weights 23 and the outer peripheral surface of the sleeve 21 and is formed into a disk shape. Each claw portion 25 of the weight 23 enters the elastic portion 22 and is molded by the elastic portion 22.

  A plurality of (six in this case) hemispherical protrusions 26 are formed on the outer peripheral portion of the surface on the front bracket 4 side, which is the upper surface of the elastic portion 22. A plurality of (in this case, three) hemispherical protrusions 27 are formed on the outer peripheral portion of the surface on the first rotor core 11 side, which is the lower surface of the elastic portion 22. The protrusions 26 and 27 are formed at equal intervals in the circumferential direction.

  Here, an example of a manufacturing process of the damper 20 will be described. First, the two weights 23 and the sleeve 21 laminated as described above are set in a predetermined mold. Next, a molten rubber material such as silicon rubber is injected into the mold and filled between the annular portion 24 of the weight 23 and the sleeve 21. The rubber material is cooled and the damper 20 is removed from the mold.

  The damper 20 is attached to the shaft 14 by press-fitting the shaft 14 into the sleeve 21, and rotates integrally with the rotor 3 including the shaft 14. In addition, the sleeve 21 is good also as a state fixed to the shaft 14 by adhering the state in which the shaft 14 was penetrated with an adhesive agent. In the damper 20 disposed between the front bracket 4 and the first rotor core 11 and fixed to the shaft 14, the protrusions 26 on the upper surface side and the front bracket 4, and the protrusions on the lower surface side. A slight gap is formed between the first rotor core 11 and the first rotor core 11.

[1-2] Operation of Stepping Motor and Damper In the stepping motor 1 configured as described above, when a driving pulse is applied to the coil 8 of the stator 2, step driving is performed by the magnetic action of the rotor 3, and the shaft 14 is intermittently driven accordingly. Rotate.

  When the rotor 3 rotates, the damper 20 also rotates integrally. However, when the rotor stops after rotating by a predetermined angle, the weight 23 tries to further rotate due to inertia in the damper 20. This excessive rotation of the weight 23 occurs momentarily due to the elastic deformation of the elastic portion 22, but the weight 23 slightly reversely rotates in the returning direction due to the elastic deformation of the reaction generated in the elastic portion 22. In this way, the weight 23 reciprocates and vibrates when the rotor 3 stops, but the vibration is absorbed by the elastic portion 22. By such an operation of the damper 20, minute vibrations of the rotor 3 are stopped in a short time, the coincidence between the natural frequency of the rotor 3 and the frequency of the drive pulse is suppressed, and the rotation becomes impossible and the output torque becomes unstable due to resonance. It is possible to prevent the occurrence of a malfunction.

[1-3] Action Effect of Damper According to the damper 20, the plurality of claw portions 25 of the weight 23 enter and engage with the elastic portion 22, so that the weight 23 is connected to the elastic portion via each claw portion 25. It will be in the state joined firmly to 22. At the time of manufacture, since the filled elastic portion 22 contracts when cooled, the elastic portion 22 presses each claw portion 25 of the weight 23 from the outer peripheral side to the inner peripheral side, and thus the weight 23 is elastic. It is firmly fixed to the portion 22. As a result, the bonding strength of the elastic portion 22 to the weight 23 is improved. In addition, even when the elastic portion 22 contracts during cooling due to the difference in thermal expansion coefficient between the elastic portion 22 and the weight 23, the claw portion 25 has entered the elastic portion 22, so that the elastic portion 22 and the weight 23 are joined. Is retained.

  In the present embodiment, the elastic portion 22 is formed by filling molding instead of vulcanization adhesion. For this reason, it does not require a vulcanization bonding step as in the prior art, and can be molded into a desired shape by cooling the elastic portion 22 after filling, thus shortening the manufacturing time and improving productivity. .

  Further, a slight gap is formed between each protrusion 26 on the upper surface side of the damper 20 and the front bracket 4 and between each protrusion 27 on the lower surface side and the first rotor core 11. When swinging in the axial direction, the impact is absorbed by the protrusion 26 abutting against the front bracket 4 or the protrusion 27 abutting against the first rotor core 11. Therefore, damage is prevented and stable operation is maintained.

[2] Second Embodiment FIG. 6 shows a damper 30 according to a second embodiment of the present invention.
The damper 30 has the same basic configuration as that of the damper 20 of the first embodiment, but differs in the shape of the weight 23 and the point that the elastic portion 22 has a band portion 22c.

  The weight 23 of the damper 30 according to the second embodiment has a plurality of linear cut portions 28 formed on the outer peripheral edge. The lengths of the cut portions 28 are the same and are formed at equal circumferential locations, and the two weights 23 are laminated with the cut portions 28 aligned. Further, the weight 23 here may not have the claw portion 25 and the inner peripheral edge may be formed in a simple circular shape, but the claw portion 25 may be formed.

  In the elastic portion 22 filled between the weight 23 and the sleeve 21 of the second embodiment, the upper surface portion 22a and the lower surface portion (not shown in FIG. 6) exposed above and below the weight 23 have apex portions 22b. It is formed in a triangular shape. The upper surface portion 22a and the apex portion 22b of the lower surface portion are formed at the same position in the circumferential direction, and the band portion 22c winds the cut portion 28 over the apex portion 22b on the upper surface portion 22a side and the apex portion on the lower surface portion side. It is formed to match. Further, on the top surface portion 22a and the apex portion 22b of the bottom surface portion, protrusions 26 and 27 (27 in FIG. 6) contact the front bracket 4 and the first rotor core 11, respectively, when the damper 30 swings in the axial direction. (Not shown) is formed.

  In the damper 30 of the second embodiment, when the elastic portion 22 filled and molded between the weight 23 and the sleeve 21 contracts during cooling, each band portion 22c causes the cut portion 28 of the weight 23 to move from the outer periphery to the inner periphery. Thus, the weight 23 is firmly fixed to the elastic portion 22. As a result, the bonding strength of the elastic portion 22 to the weight 23 is improved. Further, when a plurality of claw portions 25 are formed on the weight 23, the bonding strength of the elastic portion 22 to the weight 23 is further improved by the action of the claw portions 25.

  In the second embodiment, the cut portion 28 is formed on the outer peripheral edge of the weight 23. However, this is a form for securing the engagement state of the band portion 22c of the elastic portion, and the bonding strength is further increased. In order to improve, it is preferable to perform knurling on the surface of the cut portion 28. Further, the weight 23 may have a circular outer periphery as in the first embodiment.

[3] Others In the sleeve 21 of each of the above embodiments, it is preferable to form an uneven surface on the outer peripheral surface of the sleeve 21 by knurling or the like in order to improve the bonding strength with the elastic portion 22. In addition, in the dampers 20 and 30, two weights 23 are laminated to form a weight, but the weight configuration is not limited to this. For example, a single weight having an appropriate thickness may be used, or a plurality of weights may be laminated by a required inertia.

  Moreover, although the damper 20 (30) is the structure incorporated in the stepping motor 1, the structure attached to the protrusion end part of the shaft 14 protruded to the outward of the end bracket 5, for example may be sufficient.

  The relationship between the pulse rate and the pullout torque in the two-phase HB type stepping motor (example) having the configuration of the first embodiment and the stepping motor (comparative example) that does not include the damper 20 in the stepping motor of the first embodiment. The motor driving conditions were examined as the same. The result is shown in FIG. According to FIG. 7, it can be seen that the torque of the example extends to a higher frequency region than the comparative example, and the damper according to the present invention has a sufficient damper function.

DESCRIPTION OF SYMBOLS 1 ... Two-phase HB type stepping motor 2 ... Stator 3 ... Rotor 14 ... Shaft 20, 30 ... Damper 21 ... Sleeve 22 ... Elastic part 22c ... Band part 23 ... Weight 25 ... Claw part 26, 27 ... Projection part 28 ... Cut part

Claims (6)

A damper having a sleeve fixed to the outer periphery of the shaft, and an annular weight provided on the outer peripheral portion of the sleeve via an elastic portion,
The elastic part is filled and molded between the sleeve and the weight,
The way DOO has a pawl portion which engages the mold the elastic portion in the elastic portion,
The claw portion includes a protruding portion that bends on one side in the axial direction, and is provided at a plurality of locations equally divided in the circumferential direction of the inner peripheral edge of the weight.
The two weights are overlapped so that the protruding portions face each other and the claw portions of the other weight enter between the claw portions of one of the weights. Damper. A damper having a sleeve fixed to the outer periphery of the shaft, and a weight provided on the outer peripheral portion of the sleeve via an elastic portion,
The elastic portion is filled and molded between the sleeve and the weight, and extends between the sleeve and the weight over the upper surface and the lower surface exposed to one end side and the other end side in the axial direction . damper and having a plurality of band portion for pressing the inner circumferential side engaging with the outer peripheral portion wound around the outer peripheral portion.   The damper according to claim 2, wherein a linear cut portion with which the band portion engages is formed on an outer peripheral edge of the weight. The damper according to claim 2 or 3 , wherein a plurality of the weights are stacked.   The damper according to claim 1, wherein a plurality of protrusions are formed on both axial end surfaces of the elastic portion. A rotor including a shaft;
A stator disposed opposite to the rotor;
The damper according to any one of claims 1 to 5,
A stepping motor comprising:

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