KR20070065320A - Inner rotor vibration motor - Google Patents

Abstract

[PROBLEMS] To provide a rotor section structure in which flux between an inner rotor magnet and a field coil on the outer circumference functions efficiently while keeping the magnetic balance of the inner rotor magnet and a vibration motor in which eccentric weight arrangement position effective in obtaining a vibration force is taken into account. [MEANS FOR SOLVING PROBLEMS] The rotor section comprises a plate magnet having a generally rectangular cross-section where both ends of a noneffective flux range part located perpendicularly to the pole direction of a radially anisotropic magnet are cut off equally, and the rotor balance with respect to the central axis of rotation is kept. Meanwhile, as an unbalance weight of the rotor section, a weight inertial body made of a nonmagnetic material and placed in one of the spaces of the magnet formed by cutting off equally is eccentrically provided to the rotor section as an extra eccentric weight.

Description

Inner rotor type vibration motor {INNER ROTOR VIBRATION MOTOR}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibrating motor of a small diameter cylinder, and more particularly to an inner rotor type DC brushless motor for vibration generation in which an eccentric weight is attached to a rotor magnet.

In recent years, in our daily life, various electronic devices are equipped with a small motor as a driving source, and for each device, technologies such as motor function, miniaturization, light weight, and high output are made according to the purpose of use. have.

Similarly, in the cellular phone which is a wireless communication device, this small motor is mounted, for example, in a quiet public place where people such as art museums, concert halls, etc. gather, or in the place of consultation or important meetings. When a sudden ringing tone may cause a great deal of trouble to the people around, a small motor for vibration generation (hereinafter referred to as a vibration motor, if necessary) that informs the call notification by bodily vibration by vibrating is used.

In the case of the vibrating motor, in general, uneven centrifugal force is caused by attaching an eccentric weight which becomes a eccentric center to one end of the output rotation shaft to be driven, and the center position of the weight or the like with the rotation of the rotor part. By vibrating the entire cellular phone, the spreading rate and frequency of use of the cellular phone are increasing day by day as the spread of the cellular phone progresses.

The vibrating motor has a placenta in which the position where the eccentric weight is arranged is one end of the output rotation shaft outside the housing case of the motor, but some of them are arranged in a part of the rotor inside the housing case, for example, Patent Document 1 shown below. In the small motor described in the above and 2, "the unbalanced weight structure using the permanent magnet rotor itself as an inertial body, and the rotating motor imparts a vibration action by the imbalance moment of the permanent magnet rotor", There is a prior application publication that states that it is an unbalanced weight structure composed of an inertia body that partially removes one side of the direction and forms a rotor portion with a non-magnetic lightweight material attached to the removed portion.

Accordingly, "the vibration motor can be provided by the simple eccentric structure of the permanent magnet rotor without attaching an extra inertial body on the shaft extension which becomes the rotary shaft end part of a rotor."

Patent Document 1: Japanese Patent Application Laid-Open No. 5-304743

Patent Document 2: Japanese Patent Application Laid-Open No. 5-304744

(Initiation of invention)

(Tasks to be solved by the invention)

The vibration motors described in Patent Literatures 1 and 2 are constituted by an unbalanced weight structure having a magnet (indicated by a permanent magnet in the patent document) as the inertia body and vibrated by an unbalanced moment of the rotating rotor magnet. Although the action is obtained to some extent, the smaller the diameter of the motor main body is, the smaller the diameter of the magnet naturally becomes, and considering the magnetic unbalance of the magnet itself, the magnetic starting force as the rotor magnet structure Even if it is not obtained and the specific gravity of the magnet material is used, the effect as the weight inertia of the rotor itself is also reduced.

That is, the rotor magnet itself, which is arranged inside the cylindrical housing case, is not a high specific gravity and has a magnetically unbalanced structure. There is a concern that the rotor magnet itself cannot sufficiently acquire the driving force as the motor drive and rarely start the motor.

The present invention has been made to solve the above problems, and has a rotor structure that rotates while always maintaining the magnetic balance of the rotor magnet and effectively using the magnetic flux between the field coils, and also obtains a vibration force. It is an object of the present invention to provide a vibration motor in which an eccentric weight that becomes a high specific weight inertia is disposed at an eccentric position of an effective rotor. It is also an object of the present invention to provide a vibration motor capable of further miniaturization and miniaturization without reducing the rotational efficiency of the small motor.

(Means to solve the task)

In order to solve the said subject, in invention of Claim 1,

An inner rotor for arranging and supporting a field coil for generating an electric magnetic field on an inner wall of a cylindrical motor, and a stator part bearing disposed at both ends of the cylindrical housing case. In the cylindrical cylindrical motor,

The magnet shape of the rotor portion supported by the rotating shaft is substantially rectangular in cross section, in which both ends of the ineffective magnetic flux range portion, which are positioned in a direction orthogonal to the magnetic pole direction of the radially anisotropic magnet, are equally cut at both ends. It is a plate magnet, and the rotor is balanced with respect to the central axis of rotation,

On the other hand, as an unbalanced weight of the rotor portion, an inner rotor-type vibration comprising a heavy inertial body made of a nonmagnetic material filling one side of an evenly cut space of the magnet, eccentrically and eccentrically to the rotor portion. I do it with a motor.

Moreover, in invention of Claim 2, in invention of Claim 1,

The inner rotor type vibration motor is characterized in that the vibration motor is driven by a two-phase or three-phase DC brushless driving method.

Moreover, in invention of Claim 3, in invention of Claim 1 or Claim 2,

The combination of the magnet and the heavy inertial body constituting the rotor part is an eccentric weight made of a rare earth magnet made of an Nd magnet or an Sm magnet, and a tungsten alloy having a specific gravity of 12 or more of a nonmagnetic material. Doing.

Furthermore, in the invention described in claim 4, in the small motor according to claims 1 to 3,

Inner rotor-type vibration, characterized in that the rotating shaft is disposed at the center position of the rotor part magnet, and the eccentric weight which is a weight inertia body is fixed to the magnet side by being directly bonded to the outer peripheral surface of the magnet or covered with a resin mold. I do it with a motor.

(Effects of the Invention)

As mentioned above, according to invention of Claim 1,

For example, even when spatial constraints are added to the inner rotor portion due to a small hardening request of the vibrating motor, the effective magnetic flux for obtaining the required torque at startup while maintaining the dynamic rotor balance of the rotating magnet of the rotating operation It is possible to sufficiently obtain the basic operating characteristics of the drive output as a small motor without losing the weight.

In addition, as an unbalanced weight, a weight inertia made of a non-magnetic material that is higher in weight than the magnet material can be disposed as a weight for eccentricity in a portion that is lightly cut by the magnet shape, and thus, from the center of the entire rotor shaft. The center radius of the becomes large, and at the time of operation, a more efficient vibration force is obtained. That is, since the magnetic characteristics of the original magnet in the small motor remain the same, and the eccentric weight made of a high specific gravity material can be attached to a part of the magnet one side that becomes effective for the eccentric center, it is an inner rotor type small vibration motor. In addition, it is possible to construct a unidirectional rotor having excellent space efficiency.

Further, according to the invention described in claim 2,

The driving method of the vibration motor is based on a two-phase or three-phase DC brushless driving method, and by brushlessization, a motor structure with a long life is possible without having a physical electric rectifying mechanism composed of a brush and a commutator. In brushless, there is no worry about the life due to the contact failure due to the mechanical wear of the sliding contact portion, and the wear life of the rotary sliding part, that is, the life of the parts of the bearing portion supporting the rotor part at both ends, improves the reliability of the motor. In addition, the electric rectifying mechanism is electrically processed by a driving circuit called a driver.

In addition, for the arbitrary selection of the driving method by two phases or three phases, for example, in the case of two phases, the design of the driving circuit is easy, but a mechanical means of how to arrange the position at the time of stopping the rotor is necessary. Done. In general, the design phase of the driving circuit for starting the rotor section is larger than that of the two phases, and in the case of three phases, whether the sensor drive or the sensorless drive is performed using a hall element or the like, Affect development costs In brushless driving, the development design is largely dependent on whether a part of the dedicated driving circuit is incorporated on the driving circuit board side of the device side serving as the basic base or mounted on the vibration motor as a driving circuit attached to the outside.

Further, according to the invention described in claim 3,

The combination of the magnet and the heavy inertial body constituting the rotor part is an eccentric weight made of a rare earth magnet made of an Nd magnet or an Sm magnet, and a tungsten alloy having a specific gravity of 12 or more of a nonmagnetic material. The rotating magnetic flux required by the rotor magnets downsized and downsized in the housing case can be effectively used while the magnets are small in size.

In addition, by using a high specific gravity tungsten alloy having a specific gravity of 12 or more for the eccentric weight, it is an unbalanced weight of the rotor portion which sufficiently fits into the miniaturized and reduced diameter cylindrical motor housing case, and functions as the most efficient weight inertia while saving space. Therefore, the center radius from the rotation axis center of the whole rotor made into the rotation axis center can be enlarged, and sufficient vibration force can be obtained. Naturally, it is best to use a high specific gravity tungsten alloy close to specific gravity 18 as the weight of the eccentric weight, and it is effective to obtain vibration force. Moreover, even if it is about the specific gravity 13-16 of the range which can be manufactured as a sintering alloy, it can be used sufficiently. However, although the specific gravity 12 or more and the less than 13 of the range which can be mixed-molded including other resin components can be used as a weight inertia to some extent, the material with a specific gravity less than 12 has sufficient vibration force in consideration of the miniaturization of a product. You can't get it.

Further, according to the invention described in claim 4,

The rotating shaft is disposed at the center of the rotor magnet itself, and the eccentric weight, which is a heavy inertia body, is integrally bonded to the outer circumferential surface of the magnet by being directly bonded or integrally covered with a resin mold, thereby making it possible to machine It is possible to assemble the entire rotor section without applying any stress. In addition, the attachment and integration of the magnet and the eccentric weight to the shaft, which is a rotation shaft, as the rotor portion can reduce productivity and cost by a resin mold method using an injection molding technique. As the rare earth magnet, in addition to the sintered magnet, integral molding with a resin magnet is also possible, and it is possible to match the shape of the eccentric weight, thereby increasing the degree of freedom in designing the combined shape.

1 is an A-A cross-sectional schematic diagram (a) and a B-B cross-sectional schematic diagram (b) showing the internal structure of an inner rotor vibration motor according to the present invention.

2 is an A-A cross-sectional schematic diagram (a) and a B-B cross-sectional schematic diagram (b) showing the internal structure of an inner rotor vibration motor according to the present invention.

3 is an explanatory schematic view showing a magnet effective magnetic flux range R and an invalid magnetic flux range W of the inner rotor portion according to the present invention.

Fig. 4 is a cross-sectional reference diagram showing a modified combination example of a magnet and an eccentric weight shape of an inner rotor portion according to the present invention.

Fig. 5 is a cross-sectional reference diagram showing an example of the structure of a conventional vibrating motor having eccentric weights attached to an output shaft tip.

* Description of the symbols for the main parts of the drawings *

1, 100: vibration motor

2, 22, 32, 34, 102: magnet

3, 33, 35, 103: eccentric weights

4, 24, 104: field coil

5, 25, 105: housing case

6, 106: axis of rotation

7, 107: end flange

8, 108: bearing

9 thrust bearing

10, 110: liner

11, 111: Terminal

12, 112: feed terminal

20: resin mold

R: Magnet effective flux range

W: Magnet ineffective magnetic flux range

(The best form to carry out invention)

Embodiment 1

EMBODIMENT OF THE INVENTION Hereinafter, the structure of embodiment which concerns on this invention is described, referring FIGS. In this embodiment, a brushless drive cylindrical vibration motor in which an eccentric weight is attached to the rotor magnet is described as an embodiment of the inner rotor type motor.

 1 shows an example of the best embodiment of the present invention in a schematic sectional view. As shown in Fig. 1 (b), the shape of the magnet 2 of the inner rotor portion is an ineffective magnetic flux range portion located in a direction orthogonal to the magnetic pole direction of the anisotropic magnet material oriented in the radial direction N · S magnetic field. It is a plate-shaped magnet whose cross section is substantially rectangular in which both ends were cut equally. The material composition is preferably Nd-Fe-B-based or Sm-Co-based rare earth magnets, rare earth magnets are excellent in magnetic properties, and can cope with the size down by small hardening. 1 (b), the magnet 2 itself has a cross-sectional shape symmetrical with respect to the rotation center axis 6, and the rotor balance is also maintained dynamically.

On the contrary, as the unbalance means of the rotor portion, the original circular portion, which has become a substantially rectangular shape of the magnet 2 separately, is cut to a weight (i.e., one region in which a circular arc is cut off) and weighted more than the magnet material. As a weight inertia made of a nonmagnetic material, a rod-shaped eccentric weight 3 is integrally attached to the magnet 2 as a weight for eccentricizing the rotor portion. That is, while the magnetic characteristics of the magnet 2 in the small motor remain the same, an eccentric weight 3 made of a high specific gravity material can be attached to a part of one side of the magnet 2 effective for the eccentric center, and the rotor shaft is rotated. The center radius from the center can be increased, and an eccentric rotor portion excellent in space can be configured as the inner rotor type vibration motor. Higher specific gravity tungsten alloys are more effective when the specific gravity is closer to 18.

On the outer circumference of the rotor portion, the field coil 4 fixedly disposed on the inner wall of the housing case 5 is disposed with high accuracy with a magnetic gap therebetween. At this time, as shown in Fig. 1 (a), the rotor part has a bearing 8 on which the rotating shaft 6 is narrowed on the narrow diameter side of the housing case 5, and an end flange 7 of the other end of the housing case 5. It is axially supported by both shafts with the bearing 8 in (). At the same time, the support in the thrust direction of the rotor portion is regulated and held by the thrust bearing 9 on the end flange 7 side and the liner 10 on the other side.

On the other hand, the feed section of the field coil 4, the terminal 11 which connects and relays the tap line of the field coil 4 is attached to one end of the cylindrical field coil 4, The power supply terminal 12 is led out to the outside of the end flange 7. This power supply terminal 12 is connected to the drive circuit (not shown) by the apparatus main body side. As a drive system in this embodiment, a brushless motor of a three-phase sensorless drive system is used. By brushlessization, there is no physical commutation mechanism composed of a brush and a commutator, thereby enabling a long-life motor structure. Due to the characteristics of the motor, there is no worry of deterioration of the life due to mechanical wear of the electrical sliding contact portion, and the brushlessization is substantially abrasion of the bearing sliding points, that is, the life of the parts of the bearing portions supporting the rotor portions at both ends thereof. Longer life compared to the brush and commutator, which is a conventional sliding contact, resulting in improved motor reliability. The physical rectifying mechanism is electrically processed by a drive circuit called a driver instead.

In the vibration motor 1 shown in FIG. 1, there is no output shaft on the outside of the housing case 5, and as shown in the conventional vibration motor 100 shown in FIG. It is also different in appearance from the vibration motor structure of the type to which the semi-circumferential eccentric weight 103 formed from the high specific gravity sintered alloy, such as tungsten, is attached.

Next, the magnetic effect of the magnet 2 in this embodiment is demonstrated using the radial cross-sectional schematic shape of FIG.

For example, as shown in Fig. 3A, in the case of an anisotropic magnet having N · S magnetic poles in the radial direction of the cylindrical magnet 22, the effective magnetic flux range R for the opposing field coil 24 is shown. ) Is generally about 100 to 130 degrees on one side, and about 50 to 80 degrees on one side is the non-effective magnetic flux range portion (W), and the non-effective magnetic flux range portion (W) of the magnet 22 is applied to the magnetic effect. It's not really relevant.

Therefore, even if both ends of the said ineffective magnetic flux range part W located in the orthogonal direction with respect to a N * S magnetic pole direction are abbreviate | omitted evenly, there is little influence on the extreme characteristic fall of a magnet. Therefore, in this embodiment, as shown in Fig. 3 (b), the shape of the magnet 2 is processed into a plate-shaped magnet having a substantially rectangular cross section, and the rotor balance during the rotation operation with respect to the rotation shaft 6 which is the rotation center axis. Attached to keep.

As a result, even though the total volume of the magnet 2 is small, it is possible to sufficiently obtain the basic operating characteristics of the drive output as a small motor without losing an effective magnetic flux for obtaining the rotational torque necessary for starting the motor. Inner rotor type vibration motors actually driven exhibited performances equal to or higher than those of conventional size vibration motors, both in characteristics at startup and in vibration amount at rotation.

Embodiment 2

2 shows an example of another embodiment of the present invention. The shape of the magnet 2 of the inner rotor portion in FIG. 2 (a) shown in the schematic sectional view is similar to that shown in FIG. 1 in the direction orthogonal to the magnetic pole direction of the anisotropic magnet material oriented in the N-S magnetic field in the radial direction. It is a plate-shaped magnet whose cross section is substantially rectangular with both ends of the ineffective magnetic flux range part W located equally. Similarly, the material composition is a rare earth magnet of Nd-Fe-B type or Sm-Co type, and corresponds to the size reduction of small hardening. As also apparent from Fig. 2 (b), the magnet 2 itself has a cross-sectional shape symmetrical with respect to the rotation center axis 6, as described above, and the rotor balance is also maintained dynamically.

Similarly, the unbalance means of the rotor portion is the same as that shown in FIG. The only difference from FIG. 1 here is that the magnet 2 and the eccentric weight 3 are integrally bonded to the rotary shaft 6 by the resin mold 20. This structure is intended to reduce process steps and improve productivity in the assembly manufacturing process. By adopting the resin mold 20, only by setting each component in the molding die, a series of operations are simplified from the positioning of the dimension to the fixing of the joining mold, and the cost reduction in the rotor assembly process can be achieved. This also leads to improved impact resistance of the entire rotor section.

Further, the rotation shaft is disposed at the center position of the rotor part magnet 2 itself, and the eccentric weight 3, which is a weight inertia body, is integrally covered with a resin mold and integrated with the outer circumferential surface of the magnet 2, whereby It is possible to assemble the entire rotor portion without applying mechanical stress to the rotary shaft 6. In addition, as a rotor part, the attachment by the integration of the magnet 2 and the eccentric weight 3 with respect to the shaft which is the rotating shaft 6 is aimed at the reduction of productivity and cost by the resin mold method using the injection molding technique. The precision of parts is also improved. As the rare earth magnet material, in addition to the sintered magnet, integral molding with a resin magnet is also possible. For example, as shown in Figs. 4A and 4B, in accordance with the shape of the eccentric weights 33 and 35, respectively. The resin magnets 32 and 34 are combined to form a wider degree of freedom in design.

As described above, according to the present embodiment, the rotor structure can be realized while the magnetic balance of the rotor magnet is always maintained and the magnetic flux between the field coil is effectively used, and the rotor is effective to obtain vibration force. It can be set as the vibration motor which arrange | positioned the eccentric weight which is a high specific gravity inertia body in the eccentric position of the. Moreover, as a motor, the inner rotor type vibration motor which can aim at further downsizing and miniaturization can be provided, without reducing rotational efficiency.

Mainly, mobile communication devices such as mobile phones, which require a vibration function, mobile communication devices such as wristwatch type PHS, premises small wireless communication devices, and various information communication terminal devices such as portable PDAs, and bodily vibrations It is mounted in the general electronic equipment including electronic toys, such as a game controller and a pocket game machine.

Claims (5)

An inner rotor-type cylinder in which a field coil for generating an electric magnetic field is generated on an inner wall of a cylindrical motor, and disposed on both ends of the cylindrical housing case, and having a rotor part composed of a magnet and a rotating shaft. In the motor, The magnet shape of the rotor portion supported by the rotating shaft is substantially rectangular in cross section, in which both ends of the ineffective magnetic flux range portion, which are positioned in a direction orthogonal to the magnetic pole direction of the radially anisotropic magnet, are equally cut at both ends. It is a plate magnet, and the rotor is balanced with respect to the central axis of rotation, On the other hand, as an unbalanced weight of the rotor portion, an inner rotor-type vibration comprising a heavy inertial body made of a nonmagnetic material filling one side of an evenly cut space of the magnet, eccentrically and eccentrically to the rotor portion. motor. The inner rotor type vibration motor according to claim 1, wherein the vibration motor is driven by a two-phase or three-phase DC brushless driving method. The combination of the magnet and the heavy inertial body constituting the rotor portion is an eccentric weight made of a rare earth magnet made of an Nd magnet or an Sm magnet and a tungsten alloy having a specific gravity of 12 or more. Inner rotor type vibration motor, characterized in that. The rotating shaft is disposed at the center position of the rotor part magnet, and the eccentric weight, which is a weight inertia, is fixed to the magnet side by being directly bonded to the outer peripheral surface of the magnet or covered with a resin mold. Inner rotor type vibration motor, characterized in that attached. 4. The rotor according to claim 3, wherein a rotation axis is disposed at the center of the rotor part magnet, and the eccentric weight, which is a weight inertia, is fixed to the magnet side by being directly bonded to the outer circumferential surface of the magnet or covered with a resin mold. Inner rotor type vibration motor.

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