JP2004023937A - Bracket and stepper motor - Google Patents

Abstract

An object of the present invention is to provide a bracket capable of reducing noise and vibration increase as much as possible while realizing low cost.
A stepping motor includes a stator, brackets provided on both sides of the stator so as to sandwich the stator, and a rotor provided inside the stator. . The base of the stator 32 is constituted by a stator core 13 formed by laminating a plurality of silicon steel sheets having a substantially ring shape. The bracket 60 has a composite structure composed of the reinforcing member 70 and a resin material. The composite structure reduces cost, and at the same time, obtains high rigidity and weight, thereby reducing vibration and noise generated by the rotation of the rotor 31. I do.
[Selection diagram] Fig. 1

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a bracket that is mounted so as to sandwich a stator in a stepping motor. The present invention also relates to a stepping motor provided with the bracket.
[0002]
[Prior art]
A stepping motor is used for various devices. For example, a hybrid type stepping motor is used for an ink jet printer as one of recording apparatuses. This stepping motor is generally constituted by a stator, a pair of brackets mounted so as to sandwich the stator, and a rotor supported by a slide bearing provided on the bracket.
[0003]
FIG. 6 is an exploded perspective view of such a conventional hybrid type stepping motor (hereinafter referred to as “stepping motor”) 50. The stepping motor 50 has a rotor 31, a stator 32, and upper and lower brackets 8a and 8b. The rotor 31 includes one shaft 9, two rotor cores 11 and one magnet 6. The rotor core 11 is formed by laminating silicon steel sheets, and the number of laminations is adjusted according to various characteristics required for the stepping motor 50 in which the rotor 31 is incorporated. As the magnet 6, a magnet in which the ratio of ferrite and neodymium is adjusted according to the required torque of the stepping motor is used.
[0004]
The stator 32 is formed by laminating silicon steel plates having a substantially ring shape, and includes a stator core (iron core) 13 having a large number of arms, and a winding 15 wound around the arms (see FIG. 1). And upper and lower insulators 12a and 12b for insulating the stator core 13 and the winding 15 from each other. The winding 15 is connected to a harness unit including the board 3 and the lead wire 5.
[0005]
At the time of assembling the stepping motor 50, the rotor 31 and the stator 32 are separately assembled, and then the rotor 31 is fitted into the space inside the stator 32, sandwiched between the upper bracket 8a and the lower bracket 8b, and sealed with the screw 14. The shaft 9 of the rotor 31 is inserted through holes at the center of the upper and lower brackets 8a and 8b via the bearings 2 and 2, and a pulley 10 is attached to one end of the shaft 9. Reference numeral 7 denotes several washers provided on both sides of the rotor core 11, and the washer 7 adjusts the axial position of the rotor 31 when the rotor 31 is provided on the stator 32. .
[0006]
[Problems to be solved by the invention]
By the way, the above-mentioned brackets 8a and 8b have been conventionally manufactured by, for example, the following method. First, as a first method, there is a method of cutting an aluminum die cast. According to this method, the rigidity of the brackets 8a and 8b is improved, and the weight and the weight are increased, so that noise and vibration when the rotor 31 rotates are reduced. be able to. As a second method, there is a method of pressing a metal plate. According to this method, the brackets 8a and 8b can be manufactured easily and at low cost.
[0007]
However, in the first method (cutting of aluminum die-casting), noise and vibration can be reduced when the rotor 31 rotates, but the material and processing costs are high, and the cost of the brackets 8a and 8b is reduced. There is a disadvantage that it is significantly increased. In the second method (pressing a metal plate), the cost of the brackets 8a and 8b can be reduced. On the other hand, since the brackets 8a and 8b are lightweight, noise and vibration during rotation of the rotor 31 become remarkable and rigidity is low. Therefore, when the bearing 2 is provided on the brackets 8a and 8b, there is a disadvantage that the rotor 31 is not arranged at the center of the stator core 13 due to deformation or the like, and the characteristics of the stepping motor 50 are impaired.
[0008]
The present invention has been made in view of such a problem, and an object of the present invention is to provide a bracket capable of reducing noise and vibration as much as possible while realizing low cost.
[0009]
[Means for Solving the Problems]
In order to solve the above problem, a bracket according to claim 1 of the present application is a bracket that is mounted so as to sandwich a stator in a stepping motor, and is configured by a composite structure of a reinforcing material and a resin material. Features.
According to the first aspect of the present invention, since the bracket is configured by a composite structure of a reinforcing material made of a material having high rigidity such as metal and a resin material, the cost of the bracket is reduced by the resin material. However, the weight of the entire bracket can be increased by the reinforcing member, and the increase in noise and vibration can be reduced. Further, since the rigidity of the entire bracket can be improved by the reinforcing material, even when a rotor bearing is provided on the bracket, the positional relationship between the stator and the rotor is not impaired by the deformation of the bracket, and the stepping motor is not damaged. Can be prevented from deteriorating.
[0010]
Further, when the stepping motor is attached to, for example, a metal frame material, in order to prevent transmission of vibration from the stepping motor to the frame material, a stepping motor may be provided between the stepping motor and the frame material in some cases. Although it is necessary to interpose a vibration material, etc., since the bracket is made of a resin material, the resin material portion exhibits a vibration absorbing function, and therefore, compared to a case where the bracket is formed of a metal material, the The mounting structure can be simplified and the cost can be reduced.
[0011]
The bracket according to claim 2 of the present application is characterized in that, in claim 1, the reinforcing material and the resin material are integrally formed by resin molding using the resin material.
According to the second aspect of the present invention, since the reinforcing member and the resin material are integrally formed by resin molding using the resin material, the bracket can be manufactured easily and inexpensively. can do.
[0012]
The bracket according to claim 3 of the present application is characterized in that, in claim 1 or 2, the resin material is made of polybutylene terephthalate.
According to the third aspect of the present invention, since the bracket is made of polybutylene terephthalate, the bracket can be formed at low cost.
[0013]
A bracket according to a fourth aspect of the present invention is the bracket according to any one of the first to third aspects, wherein a base of the stator is constituted by a stator core formed by laminating a plurality of substantially ring-shaped steel plates having teeth on an inner periphery. Further, it is characterized in that it has a pressing portion for pressing the teeth of the stator core to bring the plurality of steel plates into close contact with each other.
The base of the stator is constituted by a stator core (iron core) formed by laminating a plurality of substantially ring-shaped steel plates. The steel plate has a tooth portion on an inner periphery, and a plurality of the steel plates are stacked to form tooth poles (the teeth) extending in the axial direction of the rotor so as to face the outer periphery of the rotor arranged inside the stator core. The protrusions formed by stacking the portions are formed at predetermined intervals along the circumferential direction.
[0014]
Here, the noise generated due to the rotation of the rotor is mainly generated by the laminated steel plates coming into contact with each other, and the noise is generated in an inner peripheral portion rather than an outer peripheral portion in a substantially ring shape. That is, it has been found that the problem is caused significantly by the teeth. In view of this, the bracket according to claim 4 of the present application is provided with a pressing portion that presses the inner peripheral portion of the stator core, that is, the portion of the tooth portion, so that the plurality of stacked steel plates are brought into close contact with each other. Therefore, by the pressing portion, the inner peripheral portion of the plurality of stacked steel plates is particularly firmly adhered to each other, thereby making it possible to effectively reduce noise generated when the stacked steel plates contact each other. Become.
[0015]
According to a fifth aspect of the present invention, in the bracket according to the fourth aspect, the pressing portion is formed so as to be fitted into the inner periphery of the tooth portion, so that the position of the bracket relative to the stator core in the radial direction is restricted. It is characterized in that it also serves as a means.
According to the invention as set forth in claim 5 of the present application, since the pressing portion is formed so as to be fitted into the inner periphery of the tooth portion, the pressing portion also serves as a position restricting means for restricting a radial position of the bracket with respect to the stator core. Accordingly, the radial position of the bracket with respect to the stator core, that is, the center of the stator core, and the axis of the rotor can be accurately matched with each other with a simple structure and at low cost.
[0016]
A bracket according to a sixth aspect of the present invention is the bracket according to any one of the first to fifth aspects, wherein the bearing of the rotor shaft in the stepping motor is integrally provided by resin molding using the resin material. And
According to the invention as set forth in claim 6 of the present application, the bearing of the rotor shaft in the stepping motor is provided integrally with the bracket by resin molding using the resin material. Can be provided on the bracket.
[0017]
A stepping motor according to a seventh aspect of the present invention is provided with the bracket according to any one of the first to sixth aspects.
According to the invention described in claim 7 of the present application, the stepping motor includes the bracket described in any one of claims 1 to 6. It is possible to obtain the same operation and effect as the described invention.
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to FIGS. Here, FIG. 1 is a side sectional view of a stepping motor 51 according to the present invention, FIG. 2 is an external perspective view of a reinforcing member 70 constituting the bracket 60, FIG. 3 is an external perspective view of the bracket 60, and FIG. Is a plan view of the silicon steel plate 20 (also a plan view of the stator core 13), and FIG. 5 is an enlarged side sectional view of the stepping motor 51 (partially enlarged view of FIG. 1).
[0019]
In FIG. 1, a stepping motor 51 is a hybrid type stepping motor, and includes a stator 32 and brackets 60, 60 according to the present invention provided on both left and right sides of FIG. , And a rotor 31 provided at the bottom. In FIG. 1, the same components as those of the stepping motor 50 according to the related art shown in FIG. 6 are denoted by the same reference numerals, and the description thereof will be appropriately omitted.
[0020]
The stator 32 is formed by laminating a plurality of silicon steel plates 20 (FIG. 4) each having a substantially ring shape, and includes a stator core (iron core) 13 having a large number of arms (magnetic poles) and a winding around the arms. It is composed of a winding 15 to be wound, and upper and lower insulators 12a and 12b for insulating between the stator core 13 and the winding 15.
[0021]
As shown in FIG. 4, the silicon steel plate 20 has a substantially ring shape in a plan view, and has eight magnetic poles 21 formed on its inner periphery at substantially the same intervals along the circumferential direction. I have. On the inner peripheral side of one magnetic pole 21, a plurality of teeth 22 having a substantially square shape in a plan view are formed at predetermined intervals in the circumferential direction. A plurality of teeth portions 22 are formed at predetermined intervals along the circumferential direction. Therefore, when the stator core 13 is formed by stacking a plurality of silicon steel plates 20, the teeth 22 extend on the inner peripheral surface of the stator core 13 in the stacking direction of the silicon steel plates 20 (the front and back sides in FIG. 4). Protrusions (teeth) are formed.
[0022]
Next, the circular shape indicated by the reference numeral 31 and the imaginary line is a rotor 31 (see FIG. 6), and when the rotor 31 is disposed in the stator 32 as shown in the figure, the outer peripheral surface of the rotor 31 and the tooth portion The outer diameter of the rotor 31 and the inner diameter of the stator core 13 are determined so that a predetermined interval (for example, 0.04 to 0.08 mm) is formed between the rotor 31 and the outer core 22. Further, the rotor 31 is arranged inside the stator core 13 so as to be uniformly spaced at the predetermined intervals along the circumferential direction.
[0023]
As shown in FIG. 4, the silicon steel plate 20 has a substantially rectangular outer shape, and a through hole 23 is formed at a corner of the silicon steel plate 20 for inserting the screw 14 (FIG. 1). Reference numeral 24 denotes a positioning convex portion that protrudes to the front side of the paper surface of FIG. 4, and the back side of the positioning convex portion 24 (the back side of the paper surface of FIG. 4) is a positioning concave portion (not shown). I have. When the silicon steel plates 20 are stacked, the upper and lower positioning projections 24 engage with positioning recesses (not shown) so that the silicon steel plates 20 are held (positioned) without displacement. Has become.
[0024]
Subsequently, the configuration of the bracket 60 will be described in detail. As shown in FIG. 3, the bracket 60 has substantially the same outer shape as the stator core 13, and a through hole 61 through which the screw 14 is inserted is formed at a corner thereof. As shown in FIG. 1, the brackets 60 are used as a pair. In the bracket 60 mounted on the left side of FIG. 1, a screw hole (not shown) is formed instead of the through hole 61. As a result, the brackets 60 and 60 and the stator 32 are assembled so as to be in close contact with each other by the screws 14.
[0025]
A slot 63 is formed on one surface of the bracket 60, and the insulators 12 a and 12 b (FIG. 6) enter the slot 63 when the bracket 60 is mounted on the stator 32.
[0026]
A cylindrical portion 64 is formed on the side where the slot 63 is formed. The upper portion of the cylindrical portion 64 has a stepped shape along the circumferential direction, thereby forming a protrusion 66 having a smaller radial dimension than the cylindrical portion 64. In the center of the protrusion 66, an insertion hole 62 through which the shaft 9 constituting the rotor 31 is inserted is formed.
[0027]
The cylindrical portion 64 and the protruding portion 66 reduce noise generated from the stepping motor 51 by engaging with the inner peripheral surface of the stator core 13, that is, the tooth portion 22, and reduce the noise generated by the stepping motor 51 and the center of the stator core 13 and the axial center of the rotor 31. Performs the function of matching with Hereinafter, description will be made with reference to FIG.
[0028]
FIG. 5 is an enlarged view of the vicinity of the winding 15 in FIG. When the bracket 60 is mounted on the stator 32 as shown in the figure, the step formed by the cylindrical portion 64 and the protruding portion 66 causes the teeth 22 formed on the inner periphery of the stator core 13 (a plurality of stacked silicon steel plates). 20, the teeth 22) of the uppermost and lowermost ones are engaged with each other, and the teeth 22 are pressed to tightly adhere the plurality of laminated silicon steel sheets 20 (FIG. 4) without gaps. Fulfills the function of causing In other words, the two brackets 60, 60 mounted so as to sandwich the stator core 13 allow the tooth portion 22 to be firmly adhered without any gap.
[0029]
On the other hand, the noise generated by the rotation of the rotor 31 in the stepping motor 51 is mainly generated by the stacked silicon steel plates 20 coming into contact with each other, and in particular, the noise is significantly generated in the tooth portion 22. Has been found to be. However, as described above, the tooth portions 22 are pressed from both sides by the two brackets 60 and 60 so as to be tightly adhered to each other, so that the noise can be effectively reduced. In addition, since the portion that presses the tooth portion 22 is made of a resin material having a lower elastic modulus than metal, the resin material portion can absorb the vibration generated from the tooth portion 22, thereby also effectively reducing the noise. You can do it.
[0030]
On the other hand, the upper surface of the cylindrical portion 64 as a “pressing portion” fulfills the function of bringing the tooth portions 22 into close contact with each other. The center of the stator core 13 is made to coincide with the center of the rotor, thereby functioning as a "position regulating means" for making the axis of the rotor 31 coincide with the center of the stator core 13. That is, the slide bearings 2, 2 which support the shaft 9 constituting the rotor 31 are provided on the bracket 60. Therefore, if the center of the bracket 60 is displaced from the center of the stator core 13, the center of the axis of the rotor 31 (shaft 9) is displaced from the center of the stator core 13, and the outer peripheral surface of the rotor 31 and the teeth 22 described with reference to FIG. Becomes uneven along the circumferential direction, and the rotation characteristics of the stepping motor 51 are degraded. However, the bracket 60 is provided with a protruding portion 66, and the protruding portion 66 is fitted so as to be pressed against the inner periphery of the stator core 13, so that the center of the axis of the rotor 31 (shaft 9) and the center of the stator core 13 are formed. Coincide with each other, so that occurrence of the above-mentioned inconvenience can be prevented.
[0031]
Next, returning to FIG. 3, the bracket 60 is a composite of a main body 60 a made of a resin material (in this embodiment, PBT (polybutylene terephthalate)) and a reinforcing member 70 provided integrally with the main body 60 a. It is constituted by a structure.
[0032]
The reinforcing member 70 is made of a metal material. As shown in FIG. 2, a cylindrical portion 72 is provided upright on a plate-like base 71 having a square shape in plan view. A through-hole 73 is formed in the corner of the base 71, so that the screw 14 (FIG. 1) is inserted together with the through-hole 61 (FIG. 3).
[0033]
In this embodiment, the reinforcing member 70 is provided integrally with the bracket 60 during resin molding by insert molding. As described above, since the bracket 60 is formed by the composite structure of the reinforcing member 70 and the resin material, the weight is increased by the reinforcing member 70 and the noise and vibration are reduced while the cost of the bracket 60 is reduced by the resin material. It is possible to do.
[0034]
In addition, when the bracket 60 is formed, not only the reinforcing member 70 but also the slide bearings 2 and 2 are inserted at the same time. Therefore, if the rigidity of the bracket 70 is low, the center of the stator core 13 and the rotor 31 (shaft 9) are deformed or the like. Although there is a risk of deviation from the axis, the rigidity is improved by the reinforcing member 70 in the bracket 60 according to the present invention, so that it is possible to prevent the occurrence of the above-described troubles due to the deformation of the bracket 60. Smooth rotation of the rotor 31 can be ensured.
[0035]
Further, in a case where the stepping motor 51 is attached to, for example, a metal frame member, in order to prevent transmission of vibration from the stepping motor 51 to the frame member, the stepping motor 51 may be connected to the frame member in some cases. It is necessary to interpose an anti-vibration material or the like in between, but since the bracket 60 is made of a resin material, the resin material portion exerts a vibration absorbing function, and therefore has a lower ratio than when the bracket 60 is formed of a metal material. As a result, the mounting structure of the stepping motor 51 can be simplified and the cost can be reduced.
[0036]
In addition, when the bracket 60 is formed only of the resin material, high rigidity cannot be obtained, and the effect of pressing the tooth portion 22 (noise prevention effect) may not be sufficiently obtained. Although there is a possibility that the effect of pressing the tooth portion 22 may be reduced by long-term use, such a problem can be effectively solved by using the reinforcing member 70 having high rigidity.
[0037]
In the present embodiment, the reinforcing member 70 is integrally provided by insert molding at the time of resin molding of the bracket 60. However, for example, after the main body 60a of the bracket 60 is resin-molded, the reinforcing member 70 is press-fitted. It may be provided on the bracket 60 by means.
[0038]
【The invention's effect】
As described above, according to the present invention, since the bracket is configured by a composite structure of the reinforcing material made of a material having high rigidity such as metal and the resin material, the cost of the bracket can be reduced by the resin material. As a result, the weight of the entire bracket can be increased by the reinforcing member, and the increase in noise and vibration can be reduced.
Further, since the rigidity of the entire bracket can be improved by the reinforcing material, even when a rotor bearing is provided on the bracket, the positional relationship between the stator and the rotor is not impaired by the deformation of the bracket, and the stepping motor is not damaged. Can be prevented from deteriorating.
Further, when the stepping motor is attached to, for example, a metal frame material, in order to prevent transmission of vibration from the stepping motor to the frame material, a stepping motor may be provided between the stepping motor and the frame material in some cases. Although it is necessary to interpose a vibration material, etc., since the bracket is made of a resin material, the resin material portion exhibits a vibration absorbing function, and therefore, compared to a case where the bracket is formed of a metal material, the The mounting structure can be simplified and the cost can be reduced.
[Brief description of the drawings]
FIG. 1 is a side sectional view of a stepping motor according to the present invention.
FIG. 2 is an external perspective view of a reinforcing member constituting the bracket according to the present invention.
FIG. 3 is an external perspective view of a bracket according to the present invention.
FIG. 4 is a plan view of a steel sheet material forming a stator core.
FIG. 5 is an enlarged side sectional view of a stepping motor according to the present invention.
FIG. 6 is an exploded perspective view of a stepping motor according to the related art.
[Explanation of symbols]
2 Bearing 9 Shaft 12a Upper insulator 12b Lower insulator 13 Stator core 15 Winding 20 Silicon steel plate 31 Rotor 32 Stator unit 51 Stepping motor 60 Bracket 70 Reinforcing material

Claims (7)

A bracket that is mounted so as to sandwich the stator in the stepping motor,
It is composed of a composite structure of a reinforcing material and a resin material,
A bracket characterized in that: 2. The resin material according to claim 1, wherein the reinforcing material and the resin material are integrally formed by resin molding using the resin material.
A bracket characterized in that: 3. The bracket according to claim 1, wherein the resin material is made of polybutylene terephthalate. The base body according to any one of claims 1 to 3, wherein the stator is configured by a stator core formed by stacking a plurality of substantially ring-shaped steel plates having tooth portions on an inner periphery thereof,
By pressing the tooth portion of the stator core, the stator core has a pressing portion for bringing the stacked steel plates into close contact with each other,
A bracket characterized in that: In Claim 4, the said press part was formed so that it might fit in the inner periphery of the said tooth | gear part, and also serves as the position restricting means which restricts the radial direction position of the said bracket with respect to the said stator core.
A bracket characterized in that: The bearing of the rotor shaft in the stepping motor according to any one of claims 1 to 5, wherein a bearing of the rotor shaft is integrally provided by resin molding using the resin material.
A bracket characterized in that: A stepping motor comprising the bracket according to any one of claims 1 to 6.

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