JP2839531B2 - motor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a motor such as a small DC motor used for various devices.

[Conventional technology]

Conventionally, a small DC motor shown in FIG. 20 has been used. The stator 1 has a magnet 2 for a magnetic field fixed to an inner peripheral surface of a cup-shaped case 1a, and an opening of the case 1a is closed by a plate-shaped bearing base 9. A rotor 5 provided with a winding 6 is arranged inside the magnet 2, and its rotating shaft 4 is rotatably supported by a pair of bearings 10.
Each bearing 10 is fixed to the case 1a via bearing stands 8 and 9, respectively. A brush 12 is provided on a bearing stand 9 on the right side of the drawing via a terminal 11, and a commutator 3 that contacts the brush 12 is provided on a rotating shaft 4 of a rotor 5. A bush 7 made of metal or synthetic resin is externally fitted to a portion of the rotating shaft 4 opposite to the commutator 3. This is between the bushing 7 and the bearing 10, is provided with a thrust direction clearance [delta] ₂ for absorption, such as manufacturing errors, usually the rotor 5 rotates while maintaining the gap [delta] _2.

FIGS. 21 and 22 show a motor in which the commutator 3 is arranged on the side of the rotary shaft 4 protruding from the case 1a, and the portions corresponding to those in the example of FIG. 20 are denoted by the same reference numerals. .

[Problems to be solved by the invention]

In such a motor structure, the outer diameter A (FIG. 20) of the rotating shaft 4 is smaller than the inner diameter B of the bearing 10 so that the rotating shaft 4 can rotate. clearance [delta] ₁ is present between the. Therefore, when the rotor 5 rotates,
The rotating shaft 4 oscillates by the gap δ ₁ , whereby the bearing 10
A hitting sound of the rotating shaft 4 is generated.
This hitting noise becomes noise of the equipment using the motor and gives a feeling of discomfort.

As a countermeasure for this, although the devised to minimize the gap [delta] _1, to reduce the gap [delta] ₁ accuracy is required, manufacturing is difficult. Also, if too small a gap [delta] _1, torsion acts between the rotating shaft 4 and the bearing 10 by the displacement of the axis, or not start, the disadvantage of such characteristics are lowered with increasing mechanical loss occurs. Therefore, in order to reduce the gap [delta] ₁ is limited, can not be achieved sufficiently prevent the bearing noise.

In particular, when the bearing 10 is made of a synthetic resin, there is a large difference in the coefficient of thermal expansion between the metal rotary shaft 4 and the bearing 10. reducing the gap [delta] ₁ becomes much more difficult.

An object of the present invention is to provide a motor that can prevent rattling of a rotor due to a radial gap between a rotating shaft of a rotor and a bearing and reduce bearing noise.

[Means for solving the problem]

The invention according to claim (1) is a motor in which a rotating shaft of a rotor is supported by a bearing provided on the stator, wherein the attraction force of the field magnet provided on the stator and disposed outside the rotation region of the rotor with respect to the rotor. It is asymmetric with respect to the rotation axis of the rotor.

According to a second aspect of the present invention, in a motor in which a rotating shaft of a rotor is supported by a bearing provided on a stator, the brush pressure applied to each of the pair of brushes in contact with the commutator provided on the rotating shaft of the rotor is different. It was made.

According to a third aspect of the present invention, there is provided a motor in which a rotor provided on a stator supports a rotating shaft of a rotor, wherein the rotor is provided so as to protrude from a bearing side in a radial gap between the rotating shaft of the rotor and the bearing. This is provided with a buffer having a plurality of projecting pieces that come into contact with the shaft. The buffer is made of an elastic material or the like.

According to a fourth aspect of the present invention, in a motor in which a rotary shaft of a rotor is supported by a synthetic resin bearing provided on a stator, the motor is disposed between a periphery of a shaft fitting hole of the bearing and an inner surface of the shaft fitting hole. A recess forming a thin peripheral wall portion is provided, and a buffer is provided in the recess.

[Action]

According to the structure of claim (1), the attraction of the field magnet to the rotor is asymmetric with respect to the rotation axis of the rotor, so that the rotation axis of the rotor rotates while being constantly pressed in one direction on the inner surface of the bearing. . Therefore, vibration during rotation of the rotor due to the gap between the rotating shaft and the bearing is eliminated.

According to the configuration of claim (2), the brush pressure of each of the pair of brushes in contact with the commutator is made different from each other. The inner surface rotates while being constantly pressed in one direction, and the vibration during the rotation of the rotor due to the gap between the rotating shaft and the bearing is eliminated.

According to the configuration of claim (3), the vibration of the rotor caused by the gap between the rotating shaft and the bearing is absorbed by the buffer.

According to the configuration of claim (4), since the concave portion forming the thin peripheral wall portion between the bearing inner surface and the vicinity of the shaft fitting hole of the bearing is provided, the thin peripheral wall portion is easily deformed. The easily deformable peripheral wall portion is supported from the back side by the buffer. Therefore, the rotating shaft is supported by this easily deformable peripheral wall portion of the bearing without any gap, and vibrates together with the peripheral wall portion, but this vibration is absorbed by the buffer.

〔Example〕

Embodiments of the present invention will be described with reference to the drawings. Note that the same components as those in the example of FIG. 20 are denoted by the same reference numerals, and description thereof will be omitted.

FIG. 1 shows a first embodiment of the invention of claim (1).
In this example, a pair of opposed magnets 2a ₁ and 2b ₁ provided on the inner surface of the case 1a have different axial lengths l ₁ and l ₂ from each other. One of the magnets 2a ₁ and 2b ₁ is an S pole, and the other is an N pole. The magnets 2a ₁ and 2b for this magnetic field
_{By making} the lengths l ₁ and l ₂ different from each other, the magnets 2a ₁ and
The suction force of 2b _{1 to} the rotor 5 is configured to be asymmetric with respect to the rotating shaft 4 of the rotor 5.

According to this configuration, since the magnetic flux of the magnet 2a ₁ which is short small, the magnetic attraction force for attracting the rotor 5 is reduced. Therefore, the rotor 5 is attracted to the long magnet 2b ₁ side, and the rotating shaft 4 of the rotor 5 is magnetized on the inner surface of the bearing 10.
2b Rotates while always being pressed against _one side. For this reason, the vibration at the time of rotation of the rotor 5 due to the gap between the rotating shaft 4 and the bearing 10 is eliminated, and the hitting sound between the rotating shaft 4 and the bearing 10 is eliminated. Therefore, discomfort when using the motor-using device can be eliminated. Also, the lengths l ₁ , l _{2 of} the magnets 2a ₁ , 2b ₁
Therefore, the remodeling is easy, and the precision is not required, and the manufacturing is easy.

FIGS. 2 to 6 show another embodiment of the invention of claim (1). As in the embodiment of FIG. 1, the attraction force of the field magnet to the rotor 5 is increased. Is configured to be asymmetrical with respect to the rotation shaft 4. In each of the following embodiments, parts that are not particularly described are the same as those in the embodiment of FIG.

In the embodiment shown in FIG. ₂ , one of the magnets 2a ₂ and 2b
By changing the material of ₂ , the magnetic flux is made different. The magnet 2a ₂ has an isotropic structure, and the magnet 2b ₂ has an anisotropic crystal structure. Magnet 2a ₂ , 2b ₂
Is an S pole and the other is an N pole.

In this configuration, the magnet 2b ₂ Anisotropic strong suction force is large magnetic flux than the magnets 2a ₂ of the isotropic. Therefore, the rotation shaft 4 of the rotor 5 is rotated forced always polarized in the magnet 2b ₂ side of the inner surface of the bearing 10. Therefore, bearing noise is prevented in the same manner as described above. Since the magnets 2a ₂ and 2b ₂ need only be made of different materials, the structure is simple.

FIG. 3 shows an embodiment in which a pair of opposed magnets 2a ₃ and 2b are used.
_The gaps d ₁ and d ₂ with respect to the iron core of the rotor 5 are made different by changing the thickness of ₃ . In this configuration, reduces the magnetic flux of the magnet 2b ₃ side of the side widening the gap d _2, the force for attracting the rotor 5 is reduced. This difference in suction force, rotates the rotary shaft 4 is always brought polarized magnet 2a ₃ side in the bearing 10 (FIG. 1). Thus, the structure is simple because only the gaps d ₁ and d ₂ need to be different.

FIG. 4 shows an embodiment in which a pair of opposed magnets 2a ₄ and 2b are used.
By changing the circumferential length of _4, the magnetic flux is changed and the attractive force is changed. In this configuration, the rotor 5 is brought polarized in strong attraction magnet 2a ₄ side. The structure is simple because only the circumferential length needs to be different.

In the embodiment shown in FIG. ₅ , only one magnet ₂₅ is used, and the case 1a 'is used as a yoke. Case on the opposite side of the gap between magnet ₂₅ and rotor 5
The gap between 1a 'and the rotor 5 is made larger. In this configuration, the rotor 5 is attracted to the magnet ₂₅ side,
The difference in the gap further enhances the attraction to the magnet ₂₅ side. Since only one magnet ₂₅ is required, the structure is simple.

In the embodiment of FIG. ₆ , a pair of magnets 2a ₆ and 2b ₆ on the inner surface of the case 1a are arranged so as to be displaced in opposite directions with respect to the center of the rotor 5 in the axial direction. By shifting the magnets 2a ₆ and 2b ₆ to the opposite sides in this manner, the portion of the rotor 5 on the commutator 3 side is always attracted in the direction of arrow a, and the output take-out portion is always attracted in the direction of arrow b. Therefore, the rotating shaft 4 rotates while being pressed against the upper side of the bearing 10 on the commutator 3 side and below the bearing 10 on the output taking-out side. That is, the gap δ ′ occurs only in the direction opposite to the top and bottom.
Therefore, vibration of the rotating shaft 4 due to the gap between the rotating shaft 4 and the bearing 10 is suppressed, and bearing noise is prevented. in this way,
Since it is only necessary to shift the axial positions of the magnets 2a ₆ and 2b ₆ , the types of parts do not increase and the structure is simple.

FIG. 7 shows an embodiment corresponding to the invention of claim (2). In this embodiment, the bending angles α ₁ and α ₂ of the leaf spring portions of the pair of brushes 12a and 12b in the natural state (FIG. By changing A), the brush pressure on the commutator 3 is made asymmetric, and the rotor 5 is biased in the radial direction.

According to this configuration, the commutator 3 is a brush 12a having a high brush pressure.
As a result, the brush is pressed against the brush 12b having a low brush pressure. Therefore, the rotating shaft 4 also rotates while being pressed against the brush 12b side portion on the inner surface of the bearing 10. Therefore, the rotor 5
Vibration during rotation is prevented. Thus, the brushes 12a, 12
The structure is very simple because only the bending angle of b needs to be changed.

As a structure for changing the brush pressure of the pair of brushes 12a and 12b, instead of changing the bending angles α ₁ and α ₂ as described above,
The plate thickness, plate width, material and the like of the plate spring portions of the brushes 12a and 12b may be changed. Also in this case, the structure is simple.

FIGS. 8 and 9 show another embodiment of the invention of claim (2). In this embodiment, both brushes 12a and 12b 'are made of the same material and have the same width b and the like, and one of the brushes 12b' Is formed in a fork shape by forming a slit 60.

In such a configuration, the fork-shaped brush 12
Since the brush pressure of b ′ is weaker than that of brush 12a, rotor 5
The effect of pressing against the 12b 'side is produced, and the vibration of the rotor 5 is prevented.

10 and 11 show another embodiment of the invention of claim (2). In this embodiment, the leaf spring portions of the brushes 12a and 12b are made of the same material and have the same shape. But brush 12
The carbon portion 61a of a is formed thicker than the carbon portion 61b of the brush 12b. In the case of this configuration, as shown in FIG.
The rotor 5 is pressed against the brush 12b side because the thicker brush 12a of 61a has larger deflection. Therefore, vibration accompanying rotation of the rotor 5 is prevented.

In each of the embodiments shown in FIGS. 7 to 11, the shape and structure of the pair of brushes are different to change the brush pressure on each commutator of the pair of brushes, and the structure is simple. is there.

12 to 14 show an embodiment corresponding to the invention of claim (3). In this example, a pair of bearing stands 8 'and 9' are integrally formed with bearings 10 'made of the same synthetic resin, respectively.
The bearing 10 'on the left side of the figure has a cushion consisting of elastic projections on the inner surface.
62 are provided integrally. The shock absorbers 62 are equally arranged at a plurality of positions in the circumferential direction, and are formed so that the tips thereof come into light contact with the rotating shaft 4.

According to this configuration, even if vibration is generated in the rotating shaft 4 due to the gap between the rotating shaft 4 and the inner surface of the bearing 10 ′, the vibration is absorbed by the elasticity of the buffer 62. Therefore, bearing noise is prevented. In addition, since the vibration is absorbed by the shock absorber 62, the precision of the rotating shaft 4 and the bearing 10 'is not required, and the manufacture is easy. Further, since the vibration is suppressed as described above, grease for the bearing portion which has been conventionally used is not required, and it is economical. Further, since the buffer 62 is formed integrally with the bearing base 8 ', the number of parts does not increase and the structure is simple.

Note that the buffer 62 may be provided only on the bearing 10 'on the right side of the drawing, or may be provided on both bearings 10'. In addition, the buffer 62
May be provided only at one location in the circumferential direction of the bearing 10 '.

FIGS. 15 to 18 show another embodiment of the invention of claim (3). In this example, a buffer 63 is provided separately from the bearing 10 '. The buffer 63 is formed in the shape of a ring plate, and has a plurality of buffer portions 63a at the center opening. Notch grooves 63b are formed between the buffer portions 63a. The buffer 63 is fitted into a fitting recess 64 provided in the bearing base 8 ′, and the buffer 63 a elastically contacts the outer peripheral surface of the rotating shaft 4.

In the case of this configuration, the vibration of the rotating shaft 4 is absorbed by the elasticity of the buffer 63a of the buffer 63. Buffer 63 has a buffer section
Since the notch groove 63b is provided between 63a, the buffer 63 flexes softly, preventing the rotation of the rotating shaft 4 from becoming a resistance. In this embodiment, since the buffer 63 is formed separately from the bearing stand 8 ', the structure of the buffer 63 is simple.

In each of the embodiments shown in FIGS. 12 and 15, the cushioning members 62 and 63 are made of elastic material, but any material having a cushioning effect may be used, and those having viscoelasticity and not having elasticity may be used. It may be made of a material that easily deforms.

FIG. 19 shows an embodiment corresponding to the invention of claim (4). In this example, a synthetic resin bearing base 8 "having a bearing 10" is provided, and an annular recess 65 is formed concentrically around the shaft fitting hole in the bearing 10 ". The body 66 is arranged.The buffer body 66 has a vibration absorbing or sound absorbing property, and is made of felt or rubber.
Is made of metal.

In the case of this configuration, since the annular concave portion 65 is formed around the shaft fitting hole of the bearing 10 ", the peripheral wall portion of the shaft fitting hole of the bearing 10" is formed.
10a "is thin and easily deformed, and the easily deformable peripheral wall portion 10a" is supported by the buffer 66 from the back side. Therefore, the rotating shaft 4 is attached to the easily deformable peripheral wall portion 10 of the bearing 10 ″.
a ", and vibrates together with the peripheral wall portion 10a". This vibration is absorbed by the buffer 66. Therefore, bearing noise is prevented, and grease for filling the clearance of the bearing, which has been required conventionally, is not required, and it is economical. Since grease is not used, the problem of a chemical reaction between grease and a synthetic resin is also solved.

Since the rotating shaft 4 is made of metal such as iron, and the bearing 10 "is made of synthetic resin, the difference in the coefficient of thermal expansion is large. Conventionally, the peripheral wall portion 10a" of the bearing 10 "without the concave portion 65 and the rotating shaft 4" Although it was difficult to reduce the gap between them, the vibration of the rotary shaft 4 can be satisfactorily prevented by providing the recess 65 and arranging the buffer 66 as described above.

In this embodiment, the concave portion 65 and the buffer 66 are provided in the bearing 10 ″ on the left side in the drawing, but the concave portion and the buffer may be provided in the bearing (not shown) on the right side in the drawing. 65 may not necessarily be annular, and a plurality of recesses may be provided at appropriate intervals around the bearing hole, and a buffer may be disposed in each of the recesses.

〔The invention's effect〕

In the motor according to the first aspect of the present invention, the attraction force of the field magnet to the rotor is asymmetric with respect to the rotation axis of the rotor, so that the rotation axis of the rotor rotates while being constantly pressed in one direction of the inner surface of the bearing. I do. Therefore, vibration during rotation of the rotor due to the gap between the rotating shaft and the bearing is eliminated, so that the contact noise between the rotating shaft and the bearing is eliminated, and discomfort during use can be eliminated. Also, in order to make the attraction force of the field magnet to the rotor asymmetric with respect to the rotation axis of the rotor, it is only necessary to change the shape, material or arrangement of the field magnet, such as the length and thickness, It has a simple structure, does not require precision, and is easy to manufacture.

According to the motor of the invention of claim (2), the brush pressure of each of the pair of brushes in contact with the commutator is made different from each other, so that the rotating shaft of the rotor is a bearing like the case of (1). It rotates while always being pressed in one direction of the inner surface of the. Therefore, vibration during rotation of the rotor due to the gap between the rotating shaft and the bearing is eliminated, so that the contact noise between the rotating shaft and the bearing is eliminated, and discomfort during use can be eliminated. Further, in order to make the brush pressure of the pair of brushes different from each other for the commutator, the bending angle, material, plate width, material, etc. of the leaf spring portion of the brush are changed, or a slit is provided in the leaf spring portion, Since it is only necessary to change the thickness of the carbon part, the structure is simple, the precision is not required, and the production is easy.

In the motor according to the third aspect of the present invention, the shock absorber is provided in the gap between the rotating shaft of the rotor and the bearing, so that vibration caused by the rotation of the rotor is absorbed by the shock absorber and bearing noise is reduced. Can be. Since it is only necessary to provide a buffer, the structure is simple. Furthermore, since the portion where the shock absorber contacts the rotating shaft of the rotor is a plurality of projecting pieces, the mechanical loss due to friction with the rotating shaft is reduced, and the contact between the rotating shaft and the shock absorber in the thrust direction of the rotor. The movement can be suppressed, and the noise caused by the thrust direction of the rotor can be prevented.

In the motor according to the present invention, a recess is formed around the shaft fitting hole of the bearing, and the buffer is disposed in the recess.
The peripheral wall portion of the shaft fitting hole of the bearing becomes thin and easily deformed, and does not hinder the rotation of the rotating shaft even when it comes into contact with the rotating shaft. The easily deformable shaft fitting hole peripheral wall portion is supported by the buffer from the back side, and the vibration of the rotating shaft is absorbed. Therefore, generation of bearing noise due to vibration of the rotating shaft is prevented. In addition, since it is only necessary to form the concave portion and provide the buffer, the structure is simple.

[Brief description of the drawings]

FIGS. 1 and 2 are longitudinal sectional views of each embodiment according to the invention of claim (1), FIGS. 3 to 5 are transverse sectional views of other embodiments, respectively, and FIG. 7 (A) and 7 (B) are cross-sectional views and operation explanatory views of an embodiment according to the invention of claim (2), and FIG. 8 is a still another embodiment. FIG. 9 (A), a cross-sectional view of the example,
(B) is a partial perspective view of each of the brushes, FIG. 10 is a cross-sectional view of still another embodiment, FIG. 11 is an explanatory view of its operation, and FIG. 12 is an invention according to claim (3). FIG. 13 is an enlarged sectional view of the bearing portion, FIG. 14 is an enlarged cutaway side view of the bearing portion, FIG. 15 is a partial sectional view of another embodiment, and FIG. Is a partially enlarged cross-sectional view of the same, FIG. 17 is a front view of the same shock absorber, and FIG. 18 is XVIII of FIG.
FIG. 19 is a partial sectional view of the embodiment of the invention of claim (4), FIG. 20 is a longitudinal sectional view of a conventional example, FIG. 21 is a longitudinal sectional view of another conventional example, FIG. 22 is a cross-sectional view thereof. 1 …… stator, 1a …… case, 2,2a _{1 to} 2a ₆ , 2b _{1 to} 2b ₆
... magnet, 3 ... commutator, 4 ... rotating shaft, 5 ...
Rotor, 8,9 ... bearing stand, 10 ... bearing

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tsutomu Natsuhara 1048 Kazuma Kadoma, Osaka Prefecture Matsushita Electric Works Co., Ltd. 56) References JP-A-62-53154 (JP, A) Full-open sho 57-7866 (JP, U) Full-open sho 55-120263 (JP, U) Full-open sho 56-30556 (JP, U) Full-open 55-166147 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) H02K 5/167 H02K 7/09

Claims (4)

(57) [Claims] 1. A motor in which a rotating shaft of a rotor is supported by a bearing provided on a stator, wherein the attraction force of a field magnet provided on the stator and disposed outside a rotation region of the rotor is applied to the rotor. A motor characterized by being asymmetric with respect to a rotation axis of a rotor. 2. A motor in which a rotating shaft of a rotor is supported by a bearing provided on a stator, the brush pressure of each of the pair of brushes in contact with the commutator provided on the rotating shaft of the rotor is made different. A motor characterized in that: 3. A motor in which a rotation shaft of a rotor is supported by a bearing provided on a stator, wherein the rotation of the rotor protrudes from the bearing side in a radial gap between the rotation shaft of the rotor and the bearing. A motor provided with a buffer having a plurality of projecting pieces that come into contact with a shaft. 4. A motor in which a rotating shaft of a rotor is supported by a synthetic resin bearing provided on a stator, wherein a thin peripheral wall is formed around a shaft fitting hole of the bearing and an inner surface of the shaft fitting hole. A motor comprising: a concave portion forming a portion; and a buffer provided in the concave portion.