SUMMERY OF THE UTILITY MODEL
Therefore, an object of the present invention is to provide a coreless motor, a vibration motor, and a mobile terminal device capable of obtaining a high driving force without requiring a large driving power.
To achieve the above object, a coreless motor is characterized by comprising: a rotating shaft; a coil rotating along the revolution axis and serving as a rotor; and a 1 st magnet as a stator provided on an inner peripheral side of the coil, wherein a 2 nd magnet as a stator is provided on an outer peripheral side of the coil, and magnetic poles of opposing portions of the 1 st magnet and the 2 nd magnet facing each other are different.
Since the magnet is used as the stator and the coil is used as the rotor, the rotor can be reduced in weight. The magnets are arranged on the inner and outer peripheral sides of the rotor, and a high driving force can be obtained even with the same current. Therefore, the rotor is light, and the driving force is large even with the same current, so that a high driving force can be obtained without large driving power.
In the coreless motor, the 2 nd magnets are arranged at discontinuous intervals in a circumferential direction.
When the 2 nd magnet is provided discontinuously, the 2 nd magnet may be used in a small number, which can reduce the cost.
In the coreless motor, the 2 nd magnet is arranged to be continuous in a circumferential direction.
The 2 nd magnet is provided continuously, so that the 2 nd magnet can be manufactured by integral molding.
The coreless motor may be further configured such that a region of the second magnet having the highest magnetic flux density in the circumferential direction is opposite to a region of the first magnet having the highest magnetic flux density in the circumferential direction, and a region of the second magnet having the highest magnetic flux density in the circumferential direction is opposite to a region of the first magnet having the highest magnetic flux density in the circumferential direction.
The region of the 2 nd magnet in which the magnetic flux density in the circumferential direction of each of the N-pole and S-pole is highest is opposite to the region of the 1 st magnet in which the magnetic flux density in the circumferential direction of each of the S-pole and N-pole is highest. Therefore, the 1 st magnet and the 2 nd magnet interact with each other to obtain a high magnetic flux density.
In the coreless motor, a case is provided outside the 2 nd magnet, the case is made of a soft magnetic material, and the 2 nd magnet is fixed to the case.
The 2 nd magnet is fixed to the housing, so that a fixing member is omitted.
The coreless motor may be configured such that the housing has a flat surface portion on an outer peripheral surface thereof.
Since the outer peripheral surface of the housing is provided with the flat surface portion, it is possible to obtain excellent stability by fixing the flat surface portion of the outer peripheral surface of the housing to the flat surface of the substrate. In addition, when the bracket is fixed on the base plate, the bracket which is used before is not needed to be used. Therefore, the height of the motor when fixed to the base plate can be reduced.
The coreless motor may further include a corner portion, and the 2 nd magnet may be provided at the corner portion of the housing.
The 2 nd magnet is arranged at the corner of the casing, and the space of the corner can be effectively used.
To achieve the above object, a vibration motor is characterized by comprising: any one of the coreless motors, wherein an eccentric weight is provided on the rotating shaft of the coreless motor.
The vibration motor has the effect of the coreless motor.
In order to achieve the above object, a mobile terminal device is characterized by being equipped with the vibration motor.
The vibration motor has the same effects as the vibration motor.
Detailed Description
(embodiment 1)
The following describes embodiment 1 of the present invention with reference to fig. 1 and 2. The mobile terminal device (not shown) in the present embodiment is a mobile phone (not shown), and the vibration motor 9 is fixed to a base plate (not shown) of the mobile phone. As shown in fig. 2, the vibration motor 9 is formed by providing an eccentric weight 7 on the rotation shaft 2 of the coreless motor 1.
First, the structure of the coreless motor 1 will be described. As shown in fig. 1, the coreless motor 1 includes: a housing 5; a rotating shaft 2; a coil 4 fixed to the rotating shaft 2; a 1 st magnet 3 fixed to the housing 5; and a 2 nd magnet 6 positioned on the outer peripheral side of the coil 4.
The case 5 is integrally formed of a soft magnetic material by molding or the like, and as shown in fig. 1, has a quadrangular cylindrical shape including corner portions 10, 11 and a flat surface portion 15 on the outer peripheral surface. The housing 5 supports the rotating shaft 2 through a bearing in a freely rotatable manner.
The coil 4 is cylindrical and is rotatably provided between the 1 st magnet 3 and the 2 nd magnet 6. As shown in fig. 2, the coil 4 is a rotor fixed to the rotating shaft 2.
The 1 st magnet 3 is cylindrical and fixed to the housing 5 by a magnet holder 8 as shown in FIG. 2. As shown in FIG. 1, the 1 st magnet 3 is magnetized in the circumferential direction into an N pole 3-1 and an S pole 3-2. Magnetic pole center portions 13, which are areas of the N pole and the S pole where the magnetic flux density is highest, and corner portions 11, 11 on opposite corners face each other. The 1 st magnet 3 is a stator fixed to the housing 5.
As shown in FIG. 1, the 2 nd magnet 6 has a substantially triangular cross section and is provided at corner portions 11, 11 facing the magnetic pole center portion 13 of the 1 st magnet 3. The N pole 6-1 of the 2 nd magnet 6 and the S pole 3-2 of the 1 st magnetic pole 3 are opposed to each other and fixed to the case 5. The S pole 6-2 of the 2 nd magnetic pole 6 and the N pole of the 1 st magnetic pole 3 are opposite and fixed on the shell 5. The 2 nd magnet 6 is fixed to the housing 5 by a fixing method such as an adhesive. The 2 nd magnet 6 is a stator fixed to the housing 5.
Next, the operation and effect of embodiment 1 will be described. When an electric current flows through the coil 4, an electromagnetic force for rotating the coil 4 is generated due to a magnetic flux between the 1 st magnet 3 and the 2 nd magnet 6, and the rotor including the coil 4 starts to rotate. Since the rotation shaft 2 is fixed to the coil 4, the rotation shaft 2 is rotated, and thus the eccentric weight 7 provided on the rotation shaft 2 is vibrated.
The 1 st magnet 3 and the 2 nd magnet 6 sandwich the coil 4, and the magnetic poles of the 1 st magnet 3 and the 2 nd magnet 6 facing each other are different from each other. Therefore, as the magnetic flux G shown in fig. 1 has a large component in the radial direction and a large magnetic flux density, the electromagnetic force for rotating the coil 4 is large. Further, a rotor having the coil 4 as a rotor can be obtained which is lighter than a rotor having a magnet. Therefore, the rotor is light, and the driving force is large even with the same current, and the coreless motor 1 in embodiment 1 can obtain a high driving force without large driving power. Further, since the region of the magnetic pole of the N-pole 6-1 and the S-pole 6-2 of the 2 nd magnet 6 having the highest magnetic flux density in the circumferential direction and the region of the magnetic pole of the S-pole 3-2 and the N-pole 3-1 of the 1 st magnet 3 having the highest magnetic flux density in the circumferential direction face each other, the 1 st magnet 3 and the 2 nd magnet 6 interact with each other, and a higher magnetic flux density can be obtained. Therefore, even if the driving force obtained by the same driving current is large, the same driving force can be obtained by a small driving current.
Since the 2 nd magnets 6 may be arranged at discontinuous intervals in the circumferential direction, the amount of the 2 nd magnets 6 can be reduced, which can reduce the cost.
Since the case 5 made of soft magnetic material is provided on the outer peripheral side of the 2 nd magnet 6, the magnetic flux of the 2 nd magnet 6 can be prevented from leaking out to the case 5. Demagnetization of the 2 nd magnet 6 can be suppressed, and the driving force can be increased.
The 2 nd magnet 6 is fixed to the housing 5, and unnecessary fixing members can be omitted.
The outer peripheral surface of the housing 5 is provided with a flat surface portion 15. The flat surface portion 15 is fixed to a surface of a substrate (not shown). Therefore, the stability is good, and the bracket used in the prior art is not needed when the motor is fixed on the substrate. Since it is not necessary to use a member to be pressed from above, the height of the coreless motor 1 when it is fixed to the substrate can be reduced.
The housing has a corner 11, and the 2 nd magnet 6 is provided at the corner 11 of the housing 5. Therefore, the space of the corner portion 11 can be effectively used. Further, as shown in fig. 1, since the 2 nd magnet 6 is not provided above and below the coil 4 in the height direction, the height of the coreless motor 1 can be reduced.
(embodiment 2)
The following describes embodiment 2 of the present invention. The same reference numerals are given to the same portions having the same functions and effects as those in embodiment 1, and the description thereof will be omitted. The following description mainly differs from embodiment 1.
As shown in fig. 3, in embodiment 2, the 2 nd magnet 6 provided on the outer peripheral side of the coil 4 is a cylindrical magnet that is continuous in the circumferential direction. The 2 nd magnet 6 is provided outside the coil 4 and also functions as a housing 5.
In fig. 3, the 1 st magnet 3 as a stator is cylindrical and magnetized in the circumferential direction into an N pole 3-1 and an S pole 3-2. The 2 nd magnet 6 as a stator is cylindrical, and its S pole 6-2 is opposed to the N pole 3-1 of the 1 st magnet 3, and its N pole 6-1 is opposed to the S pole 3-2 of the 1 st magnet 3. Since the 2 nd magnet also functions as the housing 5, the housing 5 does not need to be separately provided, and the cost can be reduced.
Further, since the 2 nd magnet 6 provided on the outer peripheral side of the coil 4 is a cylindrical magnet that is continuous in the circumferential direction, the 2 nd magnet can be manufactured by a method such as integral molding.
The present invention is not limited to the above embodiment, and various modifications may be made without departing from the gist of the present invention. For example, embodiment 1 may be modified as shown in fig. 4 or 5.
In fig. 4, the rectangular case 5 has two side portions facing each other, and the magnetic pole center portion 13 of the 1 st magnet 3 is provided so as to face the two side portions. The S pole 6-2 of the 2 nd magnet 6 is provided at 2 corners of the housing 5 corresponding to the N pole 3-1 of the 1 st magnet 3. An N pole 6-1 of a 2 nd magnet 6 is provided at 2 corners of a housing 5 corresponding to an S pole 3-2 of a 1 st magnet 3. The magnetic flux crossing the coil 4 can be increased compared to embodiment 1.
In fig. 5, the magnetic pole center portion 13 is arranged so that 2N poles 3-1 and S poles 3-2 of the 1 st magnet 3 are alternately opposed to the respective corner portions. At the corner of the housing 5, the magnetic pole center portions 13 of the 2 nd magnet 6 and the 1 st magnet 3 in the circumferential direction are arranged so as to correspond to each other. In contrast to fig. 4, the 2 nd magnet 6 is arranged to correspond to the central portion 13 of each magnetic pole in the circumferential direction of the 1 st magnet 3, so that the magnetic flux density can be increased and the driving force can be increased.
In the embodiment, the case 5 having a square shape is taken as an example, but the present invention is not limited thereto, and the present invention can be applied to a case 5 having an even number of corners.
Embodiment 2 may be modified as shown in fig. 6. The 2 nd magnet 6 also functions as the housing 5 as shown in fig. 5, but as shown in fig. 6, a housing 5 made of a magnetic material may be provided separately on the outer peripheral side of the 2 nd magnet 6 in addition to the 2 nd magnet. When the housing 5 is provided, the shape may be cylindrical, rectangular, or other shape.
The 1 st magnet in embodiment 2 may be provided as shown in fig. 5, that is: the N pole 3-1 and S pole 3-2 of the 1 st magnet 3 are alternately arranged. The magnet 6 in embodiment 2 is cylindrical, but is not limited to this, and may be square or have another shape.
In addition, the mobile terminal device of the present invention is exemplified by a cellular phone, but is not limited thereto, and the present invention is also applicable to a terminal device such as a personal computer or a Personal Digital Assistant (PDA).