JP4051543B2 - Bracket and stepping motor - Google Patents

Description

[0001]
BACKGROUND 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]
Stepping motors are used in various devices. For example, a hybrid type stepping motor is used in an ink jet printer as one of recording apparatuses. This stepping motor is roughly 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 includes 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 plates, and the number of laminated layers is adjusted according to various characteristics required for the stepping motor 50 in which the rotor 31 is incorporated. As the magnet 6, a ferrite and neodymium ratio 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 a stator core (iron core) 13 having a large number of arms, and a winding 15 (see FIG. 1) wound around the arms. The upper and lower insulators 12 a and 12 b for insulating between the stator core 13 and the winding 15 are configured. The winding 15 is connected to a harness unit including the substrate 3 and the lead wire 5.
[0005]
When assembling the stepping motor 50, the rotor 31 and the stator 32 are assembled separately, and then the rotor 31 is fitted into the space in the stator 32, sandwiched between the upper bracket 8 a and the lower bracket 8 b, and sealed with the screws 14. The shaft 9 of the rotor 31 is inserted into the hole in the center of the upper and lower brackets 8 a and 8 b through 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 axial position of the rotor 31 when the rotor 31 is provided on the stator 32 is adjusted by the washer 7. .
[0006]
[Problems to be solved by the invention]
By the way, the brackets 8a and 8b described above are conventionally manufactured by the following method, for example. First, there is a method of cutting an aluminum die cast as a first method. According to this method, the rigidity of the brackets 8a and 8b is improved, and the weight and the noise are reduced to reduce noise and vibration when the rotor 31 rotates. be able to. Further, as a second method, there is a method of pressing a metal plate. According to this, the brackets 8a and 8b can be manufactured easily and at low cost.
[0007]
However, in the first method (cutting of aluminum die-casting), it is possible to realize low noise and low vibration when the rotor 31 rotates, but the material cost and processing cost are high, and the costs of the brackets 8a and 8b are reduced. There is a disadvantage that it is remarkably increased. In the second method (metal plate pressing), the cost of the brackets 8a and 8b can be reduced. However, 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, the rotor 31 is not disposed 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]
Therefore, the present invention has been made in view of such problems, and an object thereof is to obtain a bracket capable of reducing noise and vibration as much as possible while realizing cost reduction.
[0009]
[Means for Solving the Problems]
In order to solve the above-described problem, a bracket according to a first aspect of the present invention 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. It is characterized by being.
According to this aspect, 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 reinforcing material can be obtained while reducing the cost of the bracket by the resin material. Thus, the weight of the entire bracket can be increased, 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 The deterioration of the characteristics can be prevented.
[0010]
Further, when the stepping motor is attached to, for example, a metal frame material, in order to prevent the transmission of vibration from the stepping motor to the frame material, it may be prevented between the stepping motor and the frame material. It is necessary to intervene a vibration material, etc., but since the bracket is made of a resin material, the resin material portion exhibits a vibration absorbing function, and therefore the stepping motor of the stepping motor is compared with the case where the bracket is formed of a metal material. The mounting structure can be simplified and the cost can be reduced.
[0011]
The bracket according to a second aspect of the present invention is characterized in that, in the first aspect, the reinforcing material and the resin material are integrally formed by resin molding using the resin material.
According to this aspect, since the bracket and the resin material are integrally formed by resin molding using the resin material, the bracket can be manufactured easily and inexpensively.
[0012]
The bracket according to a third aspect of the present invention is characterized in that, in the first or second aspect, the resin material is made of polybutylene terephthalate.
According to this aspect, since the bracket is made of polybutylene terephthalate, the bracket can be configured 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 the stator is formed by a stator core formed by laminating a plurality of substantially ring-shaped steel plates having teeth on the inner periphery. The base is configured, and has a pressing portion that closely contacts the steel plates laminated by pressing the tooth portion in the stator core.
The base of the stator is constituted by a stator core (iron core) formed by laminating a plurality of steel plates having a substantially ring shape. The steel plate has a tooth portion on the inner periphery, and a plurality of the steel plates are laminated so that the tooth poles (the teeth) extend in the axial direction of the rotor so as to face the outer periphery of the rotor disposed 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 with the rotation of the rotor is mainly generated when the stacked steel plates are in contact with each other, and the noise is an inner peripheral portion rather than an outer peripheral portion in a substantially ring shape. That is, it has been found that the above-mentioned tooth part causes the problem. Therefore, in the bracket according to this aspect, there is provided a pressing portion that closely contacts a plurality of laminated steel plates by pressing the inner peripheral portion of the stator core, that is, the tooth portion. Therefore, it is possible to effectively reduce the noise generated when the inner peripheral portions of the steel plates stacked by the pressing portion are particularly firmly in close contact with each other, and the stacked steel plates contact each other. Become.
[0015]
A bracket according to a fifth aspect of the present invention is the bracket according to the fourth aspect, wherein the pressing portion is formed so as to be fitted into the inner periphery of the tooth portion, whereby the radial position of the bracket with respect to the stator core is determined. It also serves as a position regulating means for regulating.
According to this aspect, since the pressing portion is formed so as to be fitted into the inner periphery of the tooth portion, it also serves as a position restricting means for restricting the radial position of the bracket with respect to the stator core. 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 made to coincide with each other easily and inexpensively.
[0016]
The 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. It is characterized by that.
According to this aspect, since the bearing of the rotor shaft in the stepping motor is integrally provided on the bracket by resin molding using the resin material, the rotor shaft bearing is provided on the bracket easily and inexpensively. Is possible.
[0017]
A stepping motor according to a seventh aspect of the present invention includes the bracket according to any one of the first to sixth aspects.
According to this aspect, since the stepping motor includes the bracket according to any one of the first to sixth aspects, it is possible to obtain the same operational effects as any of the first to sixth aspects described above. It becomes.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 to 5. Here, FIG. 1 is a side sectional view of the 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. FIG. 5 is a side sectional view enlarged view (partially enlarged view of FIG. 1) of the stepping motor 51. FIG.
[0019]
In FIG. 1, a stepping motor 51 is a hybrid type stepping motor, and the stator 32 and brackets 60 and 60 according to the present invention provided on both the left and right sides of FIG. And a rotor 31 provided on the main body. In FIG. 1, the same components as those of the stepping motor 50 according to the prior art shown in FIG. 6 are denoted by the same reference numerals, and description thereof will be omitted as appropriate.
[0020]
The stator 32 is formed by laminating a plurality of silicon steel plates 20 (FIG. 4) having a substantially ring shape, and has a stator core (iron core) 13 having a large number of arm portions (magnetic poles) and a winding around the arm portions. The winding 15 is composed of upper and lower insulators 12a and 12b for insulating the stator core 13 and the winding 15 from each other.
[0021]
As shown in FIG. 4, the silicon steel plate 20 has a substantially ring shape in plan view, and eight magnetic poles 21 are formed on the inner periphery thereof at substantially the same interval along the circumferential direction. Yes. On the inner peripheral side of one magnetic pole 21, a plurality of tooth portions 22 having a substantially square shape in plan view are formed at predetermined intervals in the circumferential direction. Thereby, in the inner periphery of the silicon steel plate 20, A plurality of tooth portions 22 are formed at predetermined intervals along the circumferential direction. Therefore, when the stator core 13 is configured by laminating a plurality of silicon steel plates 20, the inner circumferential surface of the stator core 13 extends in the stacking direction of the silicon steel plates 20 (the front and back direction in FIG. 4) by the teeth 22. A ridge (tooth pole) is formed.
[0022]
Next, the circular shape indicated by reference numeral 31 and the phantom line is the rotor 31 (see FIG. 6). In the state where the rotor 31 is disposed in the stator 32 as shown, 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 such that a predetermined interval (for example, 0.04 to 0.08 mm) is formed between the rotor core 22 and the stator core 13. In addition, the rotor 31 is disposed inside the stator core 13 so as to be uniformly spaced along the circumferential direction.
[0023]
As shown in FIG. 4, the silicon steel plate 20 has a substantially rectangular outer shape, and through holes 23 through which the screws 14 (FIG. 1) are inserted are formed at the corners. Reference numeral 24 denotes a positioning convex portion that is convex toward 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 that is not shown. Yes. When the silicon steel plates 20 are laminated, the upper and lower positioning projections 24 engage with the positioning recesses (not shown) so that the silicon steel plates 20 are held (positioned) without being displaced. It has become.
[0024]
Next, the configuration of the bracket 60 will be described in detail. As shown in FIG. 3, the bracket 60 has an outer shape substantially the same as that of the stator core 13, and a through hole 61 through which the screw 14 is inserted is formed at the corner. As shown in FIG. 1, the bracket 60 is used as a pair. However, 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. Thus, the brackets 60, 60 and the stator 32 are assembled in close contact with each other by the screw 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 attached to 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, whereby a protruding portion 66 having a smaller radial dimension than the cylindrical portion 64 is formed. An insertion hole 62 through which the shaft 9 constituting the rotor 31 is inserted is formed at the center of the protruding portion 66.
[0027]
The cylindrical portion 64 and the protruding portion 66 are engaged with the inner peripheral surface of the stator core 13, that is, the tooth portion 22, thereby reducing noise generated from the stepping motor 51, and the center of the stator core 13 and the axis of the rotor 31. And fulfill the function of matching. Hereinafter, a description will be given with reference to FIG.
[0028]
FIG. 5 is an enlarged view of the vicinity of the winding 15 in FIG. The step formed by the cylindrical portion 64 and the protruding portion 66 corresponds to the tooth portion 22 (a plurality of laminated silicon steel plates formed on the inner periphery of the stator core 13 when the bracket 60 is attached to the stator 32 as shown in the figure. 20 is engaged with the tooth portion 22) of the uppermost and lowermost ones, presses the tooth portion 22, and tightly adheres the silicon steel plates 20 (FIG. 4) laminated without any gaps. Fulfills the function of That is, the two brackets 60 and 60 that are mounted so as to sandwich the stator core 13 firmly adhere the tooth portion 22 portion without any gap.
[0029]
On the other hand, the noise generated with the rotation of the rotor 31 in the stepping motor 51 is mainly generated when the laminated silicon steel plates 20 come into contact with each other. In particular, the noise is remarkably generated in the tooth portion 22. It has been found to be. However, as described above, since the tooth portion 22 is pressed from both sides by the two brackets 60, 60, the noise can be effectively reduced. In addition, since the portion that presses the tooth portion 22 is a resin material having a lower elastic modulus than that of metal, the resin material portion can absorb vibration generated from the tooth portion 22, thereby also effectively reducing the noise. You can do that.
[0030]
On the other hand, the upper surface of the cylindrical portion 64 serving as the “pressing portion” serves to closely contact the tooth portion 22, whereas the protrusion 66 engages with the inner peripheral side of the tooth portion 22, thereby The center of the stator core 13 is made to coincide, thereby fulfilling the function as “position regulating means” for making the axis of the rotor 31 coincide with the center of the stator core 13. In other words, the bracket 60 is provided with the slide bearings 2 and 2 that support the shaft 9 constituting the rotor 31. Therefore, when the center of the bracket 60 and the center of the stator core 13 are shifted, the center of the rotor 31 (shaft 9) and the center of the stator core 13 are shifted, and the outer peripheral surface of the rotor 31 and the teeth 22 described with reference to FIG. The distance between them becomes non-uniform along the circumferential direction, and the rotational characteristics of the stepping motor 51 are deteriorated. However, the bracket 60 is provided with a protrusion 66, and the protrusion 66 is fitted so as to be in pressure contact with 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 is thereby obtained. Therefore, the occurrence of the above-described problems can be prevented.
[0031]
Next, referring back to FIG. 3, the bracket 60 is a composite of a main body portion 60a made of a resin material (in this embodiment, PBT (polybutylene terephthalate)) and a reinforcing member 70 provided integrally with the main body portion 60a. It is structured by structure.
[0032]
The reinforcing member 70 is made of a metal material, and as shown in FIG. 2, a cylindrical portion 72 is erected on a plate-like base portion 71 having a square shape in plan view. A through hole 73 is formed in a corner portion of the base 71, and thereby the screw 14 (FIG. 1) is inserted together with the through hole 61 (FIG. 3).
[0033]
In this embodiment, the reinforcing material 70 is integrally provided when the bracket 60 is resin-molded by insert molding. Thus, since the bracket 60 is composed of a composite structure of the reinforcing material 70 and the resin material, the weight is increased by the reinforcing material 70 and noise and vibration are reduced while the cost of the bracket 60 is reduced by the resin material. It becomes possible to make it.
[0034]
In addition, when the bracket 60 is formed, not only the reinforcing member 70 but also the sliding bearings 2 and 2 are inserted at the same time. If the rigidity of the bracket 70 is low, the center of the stator core 13 and the rotor 31 (shaft 9) are deformed due to deformation or the like. Although there is a risk of misalignment with the shaft center, in the bracket 60 according to the present invention, since the rigidity is improved by the reinforcing material 70, it is possible to prevent the occurrence of problems due to the deformation of the bracket 60 as described above. Smooth rotation of the rotor 31 can be ensured.
[0035]
Further, when the stepping motor 51 is attached to, for example, a metal frame material, in order to prevent transmission of vibration from the stepping motor 51 to the frame material, in some cases, the stepping motor 51 and the frame material It is necessary to interpose an anti-vibration material or the like between the brackets 60. However, since the bracket 60 is made of a resin material, the resin material portion exhibits a vibration absorbing function, and therefore, the bracket 60 is made of a metal material. Thus, the mounting structure of the stepping motor 51 can be simplified and the cost can be reduced.
[0036]
In addition, in the case where the bracket 60 is configured only by the resin material, high rigidity may not be obtained, and the above-described effect of pressing the tooth portion 22 (noise prevention effect) may not be sufficiently obtained, or Although 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 this embodiment, the reinforcing member 70 is integrally provided by insert molding when the bracket 60 is resin-molded. However, after the main body portion 60a of the bracket 60 is resin-molded, the reinforcing member 70 is press-fitted or the like. You may provide in the bracket 60 by a means.
[0038]
【The invention's effect】
As described above, according to 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 can be reduced by the resin material. As shown, the weight of the entire bracket can be increased by the reinforcing material, 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 The deterioration of the characteristics can be prevented.
Further, when the stepping motor is attached to, for example, a metal frame material, in order to prevent the transmission of vibration from the stepping motor to the frame material, it may be prevented between the stepping motor and the frame material. It is necessary to intervene a vibration material, etc., but since the bracket is made of a resin material, the resin material portion exhibits a vibration absorbing function, and therefore the stepping motor of the stepping motor is compared with the case where the bracket is formed of a metal material. 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 material constituting a 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 plate material constituting the stator core.
FIG. 5 is an enlarged side sectional view of the stepping motor according to the present invention.
FIG. 6 is an exploded perspective view of a conventional stepping motor.
[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 Reinforcement material

Claims (5)

A stator,
A stepping motor comprising a pair of brackets mounted so as to sandwich the stator,
In the stator, a base is constituted by a stator core formed by laminating a plurality of substantially ring-shaped steel plates having teeth on the inner periphery,
The bracket is constituted by a composite structure of a reinforcing material having a cylindrical portion and a resin material covering the reinforcing material,
The stepping motor according to claim 1, wherein in the mounted state of the bracket, the cylindrical portion presses the tooth portion of the stator core through the resin material, thereby bringing the stacked steel plates into close contact with each other. The stepping motor according to claim 1, wherein the reinforcing material of the bracket and the resin material are integrally formed by resin molding using the resin material.
Stepping motor characterized by that.   3. The stepping motor according to claim 1, wherein the resin material is made of polybutylene terephthalate. 4. The stepping motor according to claim 1, wherein a pressing portion that presses the tooth portion in the bracket is formed so as to be fitted into an inner periphery of the tooth portion. Doubles as a position restricting means for restricting the radial position of the bracket;
Stepping motor characterized by that. The stepping motor according to any one of claims 1 to 4, wherein a bearing that supports the rotor shaft is integrally provided on the bracket by resin molding using the resin material.
Stepping motor characterized by that.

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