Spindle motor and stator structure thereof

A spindle motor includes a stator structure and a rotor structure coupled to the stator structure. The stator structure has a stator base, a magnetic conductive structure surrounding the stator base, and a first buffer structure provided in the gap defined by the stator base and the magnetic conductive structure and in contact with both the stator base and the magnetic conductive structure. Furthermore, a second buffer structure and a third buffer structure are respectively provided between the stator base and the casing and between the stator base and the base plate.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a spindle motor and stator structure thereof and, more particularly, to a spindle motor and stator structure thereof having reduced vibrations and noises during operation.

2. Description of the Related Art

Referring toFIG. 1, a conventional spindle motor100includes a rotor102and a stator104riveted on a base110. The stator104consists of silicon steel sheets106and a stator base108, which are riveted together.

However, when the spindle motor100runs, the silicon steel sheets106is liable to vibrate due to the attraction of the rotor102. In that case, since no damping mechanism is incorporated in the stator structure104of the conventional spindle motor100, such vibrations are transmitted to the base110through the stator base108. Further, because the silicon steel sheets106, the stator base108, and the base110are riveted together, there must be gaps existing among them. Under the circumstance, the gaps can further enhance the vibrations of the silicon steel sheets106, the stator base108, and the base110, and thus the noises made by the spindle motor100are considerably increased as a result.

BRIEF SUMMARY OF THE INVENTION

In view of this, an object of the invention is to provide a spindle motor having reduced vibrations and noises during operation.

According to the invention, a spindle motor includes a stator structure and a rotor structure coupled to the stator structure. The stator structure has a stator base, a magnetic conductive structure surrounding the stator base, and a buffer structure provided in the gap defined by the stator base and the magnetic conductive structure and in contact with both the stator base and the magnetic conductive structure.

The spindle motor further comprises an additional buffer structure respectively provided between the stator base and a base plate connected to the stator base. In additional, a holding member can alternatively be set on a side of the stator base of the spindle motor to support and fix the additional buffer structures.

Through the design of the invention, since the stator base and the magnetic conductive structure are connected by the buffer structure, which can absorb the vibrations resulting from the rotation of the rotor structure and prevent it from being transmitted to the stator base, the casing and the base plate, the vibrations and noises are considerably reduced as the spindle motor runs.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 2illustrates a spindle motor200including a rotor structure202and a stator structure214. The stator structure214includes a magnetic conductive structure206and stator base208, and a gap216is defined therebetween by both of them. A buffer structure is provided in the gap216between the magnetic conductive structure206and the stator base208.

The rotor structure202, which includes a casing220and a magnetic structure218affixed to the underside of the casing220, encloses the stator structure214. The magnetic interaction induced between the stator structure214and the magnetic structure218of the rotor structure202causes the rotations of the rotor structure202and other structures linked to it, such as a blade, mounting plate and a disk. Inside the casing220, a shaft (not shown) is located at its center and deeply inserted in the stator base208to allow the rotor structure202to rotate about it. The magnetic structure218can be a magnetic tape having more than two magnetic poles, with two adjacent poles being in opposite polarity. The casing220can be made of metal, plastic, or magnetic conductive materials.

The stator structure214includes a stator base208, a magnetic conductive structure206, a coil204, and a buffer structure provided in the gap defined by the stator base208and the magnetic conductive structure206and in contact with both of them. In this embodiment, an adhesive substance212is utilized to form the buffer structure.

The stator base208has a cylindrical body extending along the axial direction of the spin motor200, and the cylindrical body is used for accommodating the shaft. The magnetic conductive structure206is placed around the cylindrical body and formed with a plurality of magnetic poles whose number corresponds to the magnetic poles of the magnetic structure218. The magnetic conductive structure206surrounding the stator base208can be connected to it. The coil204is wrapped around the magnetic conductive structure206, so that the magnetic polarity and strength can be controlled by the direction and amplitude of the current flowing through the coil204. The magnetic conductive structure206can be a silicon steel sheet, and the stator base208can be made of plastic, metal or a non-magnetic conductive material.

The adhesive substance212is filled in the gap216defined by the stator base208and the magnetic conductive structure206to form a connection. The adhesive substance212can fill the gap to the full or partially with cavities or bubbles remained therein, as long as the adhesive substance212both contacts the stator base208and the magnetic conductive structure206. The adhesive substance212is filled in the gap by dispensing, filling, adhering, or engaging, and the adhesive substance212can be made of resin, rubber, a foaming material, or an adhesive material.

There are several ways to assemble the adhesive substance212, stator base208and the magnetic conductive structure206together. For example, the stator base208or the magnetic conductive structure206can be first covered with adhesive substance212, and then the magnetic conductive structure206is mounted on the stator base208. Alternatively, the adhesive substance212can be applied on both the stator base208and the magnetic conductive either before or after they have been assembled.

According to the invention, since the stator base208and the magnetic conductive structure206are connected by the adhesive substance212, the adhesive substance212can absorb the vibration resulting from the rotation of the rotor structure202to prevent such vibration from being transmitted to the stator base208and the base plate210. Therefore, as the spindle motor200runs, the vibrations and noises are considerably reduced.

FIG. 3illustrates a spindle motor300according to a second embodiment of the invention. This embodiment differs from the first embodiment in that the buffer structure in the stator structure304is a flexible member302. The flexible member302can be made of rubber or elastic materials. The assembling methods for the flexible member302, the stator base208, and the magnetic conductive structure206are similar to those mentioned in the first embodiment, and thus such details are omitted in the description.

According to this embodiment, because the flexible member has high resilience, the buffer structure can absorb the vibrations and eliminate the noises more effectively.

FIG. 4illustrates a spindle motor400according to a third embodiment of the invention. The third embodiment differs from the aforesaid embodiments in that the buffer structure in the stator structure404is a filling substance402, and that a positioning part406is formed between the stator base208and the magnetic conductive structure206. The positioning part406can be either formed on the sidewall of the magnetic conductive structure206facing the stator base208or on the sidewall of the stator base208facing the magnetic conductive structure206, or both.

Since the positioning part406is naturally formed as a projection, an additional engaging force is provided when the projection engages with the filling substance402. The filling substance402can be made of foaming materials or filling materials. Further, the positioning part406can be in contact with both the magnetic conductive structure206and the stator base208to position them.

Also, the opening of the space408between the stator base208and the magnetic conductive structure206can be either faced down (faced opposite to the rotor structure202) or faced up (faced towards the rotor structure202), as shown inFIG. 4. As the opening of the space408is faced down, the engaging force provided by the positioning part406can prevent the filling substance402from leakage.

FIG. 5illustrates a spindle motor500according to a fourth embodiment of the invention. The fourth embodiment differs from the aforesaid embodiments in that an additional buffer structure524is disposed between the base plate210and the stator base208. The buffer member524is mounted between the stator base208and the base plate210and in contact with both of them. In the embodiment, the buffer member524has a C-shaped sectional profile, and wraps the edge of the base plate210. However, the buffer member can have other shape profile, such as a L-shaped sectional profile or I-shaped sectional profile in the present invention. The buffer member524can be made of a mixture of resin, rubber, foaming material, elastic material, adhesive material, filling material, or a mixture thereof.

According to this embodiment, because the buffer member524is mounted between the stator base208and the base plate210, the buffer member524can further absorb the vibrations being transmitted from the magnetic conductive structure206to the stator base208and the base plate210and eliminate the noises more effectively.526is located under the buffer members524, and the buffer member524can be in contact with the side of the holding member526.

With the installation of the holding member526, the buffer member524can be supported and be effectively fixed to prevent the buffer member524from falling off.

According to this embodiment, since the buffer structure can be a filling substance, the buffer structure can absorb the vibrations and eliminate the noises more effectively.

FIG. 6illustrates a spindle motor600according to a fifth embodiment of the invention. The fifth embodiment differs from the aforesaid embodiments in that the stator base208is composed of two stator base members208aand208b, and a buffer structure624is mounted between the two stator base members208aand208b. Each of the stator base members208aand208bhas a U-shaped sectional profile. The buffer structure624is attached to the inner sidewall of the stator base member208aand the outer sidewall of the stator base member208band is sandwiched between the two stator base members208aand208band in contact with both of them. For example, the buffer structure624can have a U-shaped sectional profile.

FIG. 7illustrates a spindle motor700according to a sixth embodiment of the invention. In the spindle motor700shown inFIG. 7, the stator base also can be formed by a stator base member208cand a stator base member208dstacked with the stator base member208c. In the present embodiment, a buffer structure724is formed between the two stator base members208cand208d. The buffer structure724is attached to the upper side of the stator base member208dand bottom side of the stator base member208c, and is sandwiched between the two suitor base members208cand208dand in contact with both of them. For example, the buffer structure724can have I-shaped sectional profile. Similarly, the buffer structure624or724can be made of a mixture of resin, rubber, foaming material, elastic material, adhesive material, filling material, or a mixture thereof.

According to this embodiment, because the buffer structure624or724is formed between the two stator base members, the buffer structure624or724can absorb the vibrations being transmitted from the magnetic conductive structure206to the stator base208and eliminate the noises more effectively.

According to this embodiment, since the buffer structure is a filling substance between the stator base members, the buffer structure can absorb the vibrations and eliminate the noises more effectively.

Although the buffer structures exemplified in the six foregoing embodiments are different, the use of these structures is not limited; in other words, structures in one embodiment can be applied in other embodiments, such as the spindle motor800shown inFIG. 8. For example, the filling substance in the third embodiment can be replaced by the flexible member, the adhesive substance, buffer member or all. For another example, the buffer structures524and302are used in the spindle motor simultaneously.

Further, though the spindle motor200is exemplified as an outer-rotor motors, one having ordinary skill in the art should understand that this invention can also be implemented in an inner-rotor motor.