KR100820767B1 - Spindle motor for hdd improved on construction of sleeve - Google Patents

Abstract

A spindle motor for a hard disk drive improved in sleeve structure is provided to assure an oil retaining space by forming an oil groove recessed at the lower end in the inner periphery of a sleeve. A spindle motor for a hard disk drive comprises a base, a sleeve(50), a stator core, a shaft(30), a thrust plate(90), and a hub. The sleeve assembled inside the base has a dynamic pressure generating groove in a radial direction. The stator core has a coil assembled to the upper part of the base. The shaft is inserted into the sleeve to have a predetermined oil gap. The thrust plate placed at the lower end of the shaft seals one side of the sleeve. The hub of a cap type has a magnet opposed to the stator core on which the coil is wound. A dynamic pressure generating groove in an axial direction is formed at the bottom of the shaft or the top of the thrust plate to provide axial dynamic pressure. A protrusion(300) is formed at the outer periphery of the shaft and a stopper(500) is protruded on the inner periphery of the sleeve so that the separation of the shaft is prevented. An oil groove(510) is formed along the circumference of the inner periphery of the sleeve.

Description

SPINDLE MOTOR FOR HDD IMPROVED ON CONSTRUCTION OF SLEEVE}

1 is a view for briefly explaining the structure of a typical hard disk drive.

2 is a view for conceptually explaining a conventional spindle motor for a hard disk drive.

3 is a view showing a spindle motor for a hard disk drive having an improved structure of the sleeve of the present invention.

Figure 4 is an enlarged view of a portion of the spindle motor for a hard disk drive improved structure of the sleeve of the present invention.

5 is a view for explaining a sleeve of the spindle motor according to the present invention.

6 is a view for explaining a shaft of the spindle motor according to the present invention.

7 is a view for explaining the thrust plate of the spindle motor according to the present invention.

*** Brief description of the reference numerals for the main parts of the drawings ***

1: platter 2: spindle motor

3: head 4: head arm

5: sppping motor

10: HUB 20: MAGNET

30: shaft 40: thrust bearing (conventional)

50: SLEEVE 60: Base

70: coil wound stator core 80: groove (GROOVE)

90 thrust plate

300: jam jaw 500: stopper

510: Oil Receiving Groove

The present invention forms a protrusion stopper on the upper end of the inner diameter of the sleeve to prevent the shaft from being separated, the lower end of the inner diameter of the sleeve to form an oil receiving groove recessed inward to secure the oil holding space structure Relates to an improved spindle motor for a hard disk drive.

In general, a hard disk drive refers to an auxiliary memory device that stores and reads data while rotating a magnetic aluminum plated aluminum substrate. However, a hard disk drive cannot be used interchangeably with other devices as needed. Because of its size, it is widely used in small computers. In particular, small hard disk drives are widely used in personal computers because they are suitable for use in personal computers. The capacity of the hard disk drive used in such a personal computer is 1GB level in the mid-1990s, and 16GB level is common in the late 1990s. Globally, storage capacity is growing at 60% per year, with prices falling 12% per quarter.

Usually, the hard disk drive has a platter shaped like a record plate, and a concentric circle called a track is drawn thereon to record data electronically in the concentric circle. As shown in FIG. (1) consists of a stacked hard disk, spindle motor (2), head (3), head arm (4) and stepping motor (5).

The platter (1) is a thin coating of magnetic magnetic material on a metal disc. Due to the limitation of the capacity that can be recorded on one sheet, a high capacity hard disk uses several platters (1), depending on the size and number of The size of the hard disk is determined.

The spindle motor 2 rotates at a constant speed (eg, 3600 rpm, 5400 rpm, 7200 rpm) when the power is turned on by a motor that rotates the platter, and one or more platters 1 are coupled to the spindle shaft to form a plurality of platters. (1) is made to rotate simultaneously. Controlling the correct turnover rate of this spindle motor (2) is of paramount importance for reliable reading and writing of data.

The head 3 then moves horizontally above and below the rotating platter 1 to read and write data to the platter 1. The head arm 4 is an arm that enables the head 3 to move and adjusts the position of the head 3 under the command of the controller chip.

Finally, the stepping motor 5 is a driving force for moving the head 3 to the position of the platter 1, and the access time is determined according to the performance of the motor is good or bad.

In particular, the spindle motor 2, which is the field to which the present invention is applied, belongs to a brushless-DC motor and transmits a rotational force to the center of the platter 1, which is the disc of the disc. As a motor for rotating the platter (1), a laser beam scanner motor for a laser printer, a motor for a floppy disk drive (FDD), a compact disk (CD) or a DVD (Digital Versatile Disk) as well as a hard disk drive. It is widely used as a motor for an optical disk drive.

In recent years, in a device requiring high capacity and high speed driving force such as the hard disk drive, in order to minimize noise and non-repetitive run out (NRRO), a driving load (or driving friction) is less than that of a conventional ball bearing. The trend is to use spindle motors with hydrodynamic bearings.

Here, the hydrodynamic bearing is basically a thin oil film formed between the rotating body and the fixed body to support the rotating body with the pressure generated during the rotation, characterized in that the friction load is reduced because the rotating body and the fixed body do not contact each other. .

As shown in FIG. 2, the internal structure of the conventional spindle motor to which the hydrodynamic bearing is applied includes a base 60, a sleeve 50, a stator core 70 wound around a coil, a shaft 30, and the like. The thrust bearing 40, the hub 10 and the magnet 20 is composed of the assembly form is fixed to the sleeve 50 perpendicular to the inner side of the base 60, the coil outside the upper side of the base 60 The wound stator core (70) is mounted, and the rotating shaft which is coupled to the shaft (30) and the thrust bearing (40) through the inner center of the sleeve (50) is rotatably inserted. The upper end of the shaft 30 is coupled to the hub 10 of the cap shape is open downward. In addition, the magnet 20 is attached to a position facing the stator core 70 inside the end portion of the hub 10, wherein the outer circumferential surface and the sleeve of the assembly in which the shaft 30 and the thrust bearing 40 are coupled to each other are attached to the magnet 20. An oil gap is formed between 50), and the oil gap is filled with a fluid such as lubricating oil or grease.

Therefore, the spindle motor having the hydrodynamic bearing structure as described above has a hub 10 and a shaft 30 coupled thereto by an electromagnetic repulsive force acting between the stator core 70 and the magnet 20 when an external power source is applied. Combination combined with the thrust bearing 40 is rotated.

In addition, as shown in the drawing, a plurality of grooves 80 are formed along the outer surface of the shaft 30 and the thrust bearing in a comb pattern (Herringbone) shape or a spiral shape (Spirial), so that the oil gap is rotated. The oil filled in is moved toward the center of the groove by the pressure gradient to generate the fluid dynamic pressure to support the shaft and prevent the fluid filled in the oil gap from scattering.

In this case, the groove is formed in the shaft 30 and the thrust bearing 40 as shown in the drawings, but is not limited thereto, and the groove may be formed at various positions such as the lower surface of the hub 10 of the inner circumferential surface of the sleeve 50. It may be.

Therefore, the stable rotation of the rotating body combined with the shaft 30 and the thrust bearing 40 is required for stable driving, and for this purpose, the radial directional dynamic pressure and the axial dynamic pressure supporting the shaft 30 are required. It is strongly related to stable occurrences.

However, the conventional spindle motor shown in FIG. 2 must use thrust bearing 40 to generate axial dynamic pressure, and therefore, the size of the spindle motor is limited due to the space occupied by the thrust bearing 40. In addition, in processing radial dynamic pressure generating grooves, the processing area of the grooves is reduced on the outer circumferential surface of the shaft 30 or the inner circumferential surface of the sleeve 50 in contact with the shaft 30, so that the dynamic pressure in the radial direction is weakened and the rotation of the rotating shaft is inhibited. It becomes a requirement.

Therefore, it is very difficult to maintain the structure of the spindle motor shown in FIG. 2 due to the above problem in the current miniature hard disk drive spindle motor of 2.5 "or less, and there are many problems to apply it.

In addition, in the structure of the spindle motor, in the case of the bearing oil for maintaining the dynamic pressure of the fluid bearing, if the spindle motor is exposed for a long time under environmental conditions such as high temperature, the oil may evaporate or vaporize, causing the dynamic pressure to be lowered. It shortens the lifespan and performance of the shaft 30, but in the case of the shaft 30, it has a predetermined oil gap in the sleeve 50 and couples to the inside of the hub, but there is no special fixing device, so that it can be easily detached in the event of external impact. There is a problem.

Accordingly, the present invention has been made in view of the above-described problems, and the dynamic pressure in the axial direction is maintained and the radial pressure in the radial direction is further improved, and the spindle motor is miniaturized even when the thrust bearing as a component of the conventional spindle motor is removed. It is an object of the present invention to provide a spindle motor for a hard disk drive.

In addition, it is another object to provide a spindle motor for a hard disk drive that can improve the structure of the sleeve to prevent the departure of the shaft, and to increase the initial injection amount of the bearing oil to extend the durability resistance of the motor by oil evaporation. .

In order to achieve the object of the present invention as described above, the spindle motor for a hard disk drive having an improved structure of the sleeve includes a base (60); A sleeve 50 coupled to the inside of the base 60 and having a radial direction dynamic pressure generating groove 81 formed therein to induce fluid dynamic pressure to an inner circumferential surface thereof; A stator core (70) wound around a coil coupled to an upper portion of the base (60); A shaft 30 inserted into the inner diameter portion of the sleeve 50 and rotating therein; A thrust plate (90) disposed at a lower end of the shaft (30) to seal one side of the sleeve (50); And a hub (10) having a magnet (20) installed to face the stator core (70) in which the coil is wound on an inner side thereof in a cap shape which is opened downwardly, wherein the shaft (30) is configured. An axial dynamic pressure generating groove 82 for providing an axial dynamic pressure on the lower surface of the thrust plate 90 or the thrust plate 90 adjacent thereto is formed, and the shaft 30 is A locking jaw 300 is formed to protrude to an outer circumferential surface, and the inner diameter portion of the sleeve 50 into which the shaft 30 is inserted is close to the locking jaw 300 at a portion corresponding to the locking jaw 300. To prevent the departure of the shaft 30 by forming a projection-shaped stopper 500 protruding to the outside, and the oil receiving groove 510 recessed inward along the circumferential direction of the inner diameter portion of the sleeve 50 ) Is characteristic.

Here, the axial dynamic pressure generating groove 82 is characterized in that the processing using any one of cutting, electrolytic processing and press working.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention, and like reference numerals designate like parts throughout the specification. In addition, when a part is said to "include" a certain component, which means that it may further include other components, except to exclude other components unless otherwise stated.

Now, a spindle motor for a hard disk drive according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. The following terms are defined in consideration of functions in the present invention, and are intended to be used by users, operators, or customs. Can be different. Therefore, the definition should be made based on the contents throughout the present specification.

3 is a view showing a spindle motor for a hard disk drive with improved structure of the sleeve of the sleeve of the present invention, Figure 4 is a partially enlarged view of a spindle motor for a hard disk drive with improved structure of the sleeve of the present invention, Briefly explaining the spindle motor according to the configuration of the spindle motor according to the present invention as shown in the drawings, the base 60, the sleeve 50 is coupled to the inside of the base 60, the upper portion of the base 60 Coupling coil is wound around the stator core 70, the shaft 30 is inserted into the inner diameter portion of the sleeve 50 is inserted and rotated, the lower end of the shaft 30 and the sleeve 50 Thrust plate (90) for sealing one side of the, and a downwardly open cap (Cap) shape of the hub (10) is installed on the inner side to face the stator core 70 wound the coil wound on the inner side (10)do.

At this time, the spindle motor according to the present invention is applied to the hydrodynamic bearing, radial radial pressure generating grooves 81 and axial dynamic pressure generating grooves 82 are formed to induce dynamic pressure generation.

On the other hand, the present invention can remove the thrust bearing applied to the conventional spindle motor to ensure the machining area of the radial direction dynamic pressure generating groove 81 more than the conventional spindle motor to improve the dynamic pressure in the radial direction The shaft 30 is stably supported.

In addition, the lower end of the sleeve 50 to form an oil receiving groove 510 recessed inward in the circumferential direction of the inner diameter portion to utilize as an oil reservoir of the fluid bearing and to compensate for the insufficient oil amount, the spindle motor When prolonged exposure to environmental conditions such as high temperature caused by the operation of the oil can reduce the dynamic pressure by evaporation or vaporization to reduce the life of the entire hard disk drive.

To describe each component of the spindle motor according to the present invention in detail,

Spindle motor such as the present invention is divided into a rotating part and a fixed part, first, the rotating part has a hub shape in the center of the hub 10 and the hub 10 is installed on the inner side in a cap shape which is opened downward one side It consists of a shaft 30 to engage. At this time, the rotation axis of the spindle motor is to be the shaft (30).

On the other hand, the fixing part has a predetermined oil gap so that the shaft 30 is rotatable, and coupled to the shaft 30, one side is closed by the thrust plate 90, the inner diameter portion of the radial pressure in the radial direction (Radial) direction A radial direction dynamic pressure generating groove 81 for generating a sleeve 50 formed at a predetermined position, a base 60 for fixing the sleeve 50, and the base 60 to face the magnet 20. Coil coupled to the) is made of a stator core (70) wound.

In this case, the radial direction dynamic pressure generating groove 81 for generating the dynamic pressure in the radial direction may be formed in the inner diameter portion of the sleeve 50 as shown in FIG. 3, but is not limited thereto. Radial direction dynamic pressure generating grooves may be formed in the outer diameter portion of the shaft 30 facing the sleeve 50.

Compared with the conventional spindle motor, the spindle motor according to the present invention does not apply thrust bearings, and thus provides a spindle motor for a hard disk drive improved by changing the structure of the sleeve 50 and the shaft 30.

Here, when looking at the enlarged view of the part shown in Figure 4, the shaft 30 forms a locking projection 300 protruding to a predetermined size to its outer peripheral surface, the sleeve 50 is inserted into the shaft 30 The inner diameter portion of the stopper 300 is formed in the projection corresponding to the engaging projection 500 to the outside in the portion corresponding to the locking projection 300 to form a stopper 500 when driving the spindle motor or external shock of the hard disk drive It is to prevent the separation of the shaft 30 by the.

In addition, the lower end of the sleeve 50 to form an oil receiving groove 510 recessed inward in the circumferential direction of the inner diameter portion to utilize the reservoir of oil.

In addition, the dynamic pressure in the axial direction due to the thrust bearing used in the conventional spindle motor is formed by forming a groove on the lower surface of the shaft 30 or the upper surface of the corresponding thrust plate 90 in the axial direction. The dynamic pressure is generated to provide stable rotation of the rotating part together with the dynamic pressure in the radial direction.

In addition, since the thrust bearing is not used as described above, the oil holding space is largely secured in the space occupied by the conventional thrust bearing, so that the problem caused by the oil can be solved in the reliability test, and the dynamic pressure in the radial direction is reduced. In order to increase the inner diameter portion of the sleeve 50 or the outer diameter portion of the shaft 30 adjacent thereto, the characteristic that can further secure the processing area of the radial direction dynamic generating grooves.

Therefore, by increasing the dynamic pressure in the radial direction to support the shaft 30 more stably to improve the stable characteristics of the product, eliminating the difficulty of directionally assembled according to the processing direction of the groove formed in the conventional thrust bearing. There are features that can be done.

Referring to the operation structure of the spindle motor according to the present invention, by coupling the magnet 20 to the inner surface of the hub (10) having a cap shape downwardly open, the coil is coupled to the base (60) wound stator core The hub 10 rotates with the electric repulsive force formed by the current and voltage applied to the 70, and the shaft 30 coupled thereto rotates together. At this time, by using the fluid dynamic bearing as a bearing means for smooth and stable rotation of the hub 10, the friction and resistance of the object during the rotational movement, as well as the noise and vibration significantly reduced.

At this time, the shaft 30 which is integrally coupled to one side of the hub 10 to be integrated is inserted into the sleeve 50 and coupled to each other, but is coupled to form an oil gap, which is a space into which oil is injected.

With the oil filled in the oil gap, the axis of rotation rotates with the hub 10 in the sleeve 50 that couples to the base 60. At this time, radial direction dynamic pressure generating grooves 81 for generating dynamic pressure in a radial direction of the rotating shaft are respectively formed on upper and lower portions of the inner circumferential surface of the sleeve 50. Here, the radial direction dynamic pressure generating groove 81 is formed in the inner circumferential surface of the sleeve 50 in FIGS. 3 to 4, but is not limited thereto, and the sleeve 50 is as shown in FIG. 6. It may be formed respectively in the upper and lower outer peripheral surface of the shaft 30 in close proximity to the inner peripheral surface of the.

Figure 5 is a view for explaining the sleeve of the spindle motor according to the present invention, Figure 6 is a view for explaining the shaft of the spindle motor according to the present invention, Figure 7 illustrates a thrust plate of the spindle motor according to the present invention. It is a figure for following.

Figure 5 is a cross-sectional view showing an improved sleeve 50 according to the present invention, by changing the structure of the upper and lower portion of the inner diameter of the sleeve 50 in the present invention, to provide a stable rotation of the rotating portion without using a conventional thrust bearing And it is characterized by improving the durability of the hard disk drive.

The sleeve 50 of the spindle motor according to the present invention forms an inner diameter portion having a predetermined diameter, and the shaft 30 shown in FIG. 6 is inserted into and coupled to the inner diameter portion with a predetermined oil gap.

When the inner diameter portion of the sleeve 50 is seen, the upper and lower portions of the inner diameter portion are characterized. First, the upper portion of the inner diameter portion of the sleeve 50 has a predetermined size and protrudes in the shape of a stopper 500 protruding outward. Is formed along the circumferential direction, which prevents the shaft 30 from being separated during an external impact of the hard disk drive in correspondence with the locking step 300 of the shaft 30 illustrated in FIG.

In addition, the sleeve 50 has a radial direction dynamic pressure generating groove 81 which induces dynamic pressure generation in a radial direction when the rotating part is rotated, respectively, on the upper and lower portions of an inner circumferential surface, wherein the radial ) Dynamic pressure generating grooves 81 are formed in a comb pattern (Herring-bone) or a spiral pattern (Spiral).

On the other hand, the lower end of the inner diameter of the sleeve 50, the oil receiving groove 510 recessed inwardly is formed along the circumferential direction of the inner diameter, the oil for constituting the dynamic bearing into the inside of the sleeve 50 It is introduced and used as a secondary reservoir for bearing oil. This increases the initial oil injection amount of the spindle motor to store the oil in the oil receiving groove 510, and can solve the problem of lowering the dynamic pressure by evaporating or vaporizing the oil when exposed to environmental conditions such as high temperature for a long time, This has the feature of extending the durability reduction performance of the motor.

That is, the oil receiving groove 510 stores the emergency oil, and then supplements the insufficient oil according to the environmental conditions of the spindle motor with the emergency oil.

In addition, when looking at the upper outer side of the sleeve 50, it can be seen that the diagonally processed along the circumferential direction of the sleeve 50, which is to close the hub 10 to prevent the oil leakage of the conventional When the surface area is wider than when processed into a flat surface, the surface tension of the widened portion increases, and when the spindle motor does not rotate, the surface tension increases to form a thin oil film by oil, which causes oil to leak to the outside. Can be prevented.

6 shows the shaft 30 according to the present invention, which is inserted into the inner diameter portion of the sleeve 50 with a predetermined oil gap, and is characterized in that thrust bearings are removed in comparison with the conventional art. Accordingly, the axial dynamic pressure generating groove 82 for the dynamic pressure in the axial direction due to the conventional thrust bearing is formed on the lower surface of the shaft 30 or the upper surface of the thrust plate 90 adjacent thereto. Done.

In addition, the shaft 30 forms a locking projection 300 protruding to a predetermined size to the outer circumferential surface thereof. In other words, the outer circumferential surface of the shaft 30 is composed of a first diameter portion and a second diameter portion having an original diameter, and the locking step 300 is formed therebetween. This corresponds to the stopper of the sleeve 50 to prevent the departure of the shaft 30 during the external impact of the hard disk drive.

In addition, as shown in FIG. 5, a radial direction dynamic pressure generating groove 81 for providing a dynamic pressure in a radial direction may be formed on the inner circumferential surface of the sleeve 50, but is not limited thereto. As shown in the radial direction dynamic pressure generating groove 81 ′ may be formed on the outer circumferential surface of the shaft 30 close to the inner circumferential surface of the sleeve 50.

At this time, the radial direction dynamic pressure generating groove 81 can further improve the dynamic pressure in the radial direction by further securing the processing area of the groove compared to the spindle motor to which the conventional thrust bearing is applied.

On the other hand, the thrust plate 90 for closing the open lower side of the sleeve 50 shown in Figure 7 is in contact with the bottom surface of the shaft 30 in the configuration of the spindle motor, as shown in the drawing, At this time, in order to replace the axial dynamic pressure due to the thrust bearing applied to the conventional spindle motor, the thrust plate 90 has an axial dynamic pressure generating groove on its upper surface which is in contact with the lower surface of the shaft 30. (82) is formed.

The axial dynamic pressure generating groove 82 formed on the thrust plate 90 is formed of a herring-bone or spiral pattern in the same manner as the radial direction dynamic pressure generating groove 81. do.

In addition, the above-mentioned axial dynamic pressure generating groove 82 is formed on the upper surface of the thrust plate 90 in the drawing, but is not limited thereto, and is formed on the lower surface of the shaft 30 to form an axial axis. Dynamic pressure in the direction may be provided.

Thus, by forming the axial dynamic pressure generating groove 82 on the upper surface of the thrust plate 90, the axial dynamic pressure provided by the deleted thrust bearing can be replaced, and the thrust bearing is deleted. Accordingly, the thickness of the spindle motor can be reduced and miniaturized.

On the other hand, the axial dynamic pressure generating groove 82 formed in the thrust plate 90 can be processed through various processing methods.

First, a cutting method is a cutting method of cutting or shaving a workpiece into a desired shape using a cutting tool, wherein the workpiece is a lower end surface of a shaft for forming an axial dynamic pressure generating groove or The upper surface of the thrust plate adjacent to this becomes.

Representative machines of the above cutting process are milling, lathe, drilling machine and boring machine using a rotating force, and cutting tools include bite, awl, chisel, string, brooch, milling cutter, hob, etc. In addition to processing with such cutting tools, grinding with grinding wheels is one of the cutting, and honing, super finishing, ultra grinding, and the like are also included in the cutting process.

Another machining method is press machining, which is mainly used for sheet metal, but is also used as a machining method for engraving a predetermined shape.

The press processing is a method of plastically deforming a workpiece by mounting a mold having a predetermined panel shape between press machines for up and down reciprocation, and applying the same to the processing of grooves. First, the shaft or thrust plate, which is the workpiece, is fixed to the lower disc of the mold, and the upper disc having the groove shape embossed presses the workpiece of the lower disc up and down and presses it with a strong force. It is a processing method which forms a groove shape in a to-be-processed object.

In addition, electrolytic machining, which is one of the axial dynamic pressure generating grooves, uses electrolysis, also called electrolytic machining, and is an anode product that prevents the progress of electrochemical melting of metallic materials. An oxide film is formed, which is processed while removing it. If a tool made in the shape to be processed, that is, a groove-shaped tool is used as a cathode, and a material, that is, a shaft or thrust plate is used as an anode, both of them are immersed in the electrolyte and passed through an electric current, the material is processed like the surface shape of the cathode. do. As a general tool, it is used for machining hard carbide, heat resistant steel, etc., which is difficult to process.

Although the present invention has been shown and described with reference to certain preferred embodiments, the present invention is not limited to the above-described embodiments, and the general knowledge in the technical field to which the present invention pertains does not fall within the spirit of the present invention. Various changes and modifications may be made by the possessor.

The spindle motor for a hard disk drive having an improved structure of the sleeve according to the present invention having the configuration as described above can further secure a processing area of a radial directional dynamic pressure generating groove by removing a thrust bearing applied to a conventional spindle motor. By increasing the radial pressure in the radial direction, it is possible to stably support the shaft, which is the rotating shaft, and also to assemble the spindle motor, thus eliminating the difficulty of directionally assembling the grooves formed in the conventional thrust bearing. The effect of improving the assembly is produced.

In addition, the thickness of the spindle motor is reduced and downsized by forming a dynamic pressure generating groove at the lower end of the shaft or on the upper end of the thrust plate which is in contact with the axial dynamic pressure of the conventional thrust bearing, and reducing the thickness of the spindle motor. It is formed to prevent the departure of the shaft which is a rotating shaft has the effect of extending the durability to the external environment.

In addition, by forming an oil receiving groove at the bottom of the sleeve to increase the initial oil injection amount to prepare for the oil to evaporate when exposed to the environment, such as high temperature of the spindle motor, there is an effect to extend the durability reduction performance of the spindle motor.

Claims (2)

Base 60; A sleeve 50 coupled to the inside of the base 60 and having a radial direction dynamic pressure generating groove 81 formed therein to induce fluid dynamic pressure to an inner circumferential surface thereof; A stator core (70) wound around a coil coupled to an upper portion of the base (60); A shaft 30 inserted into the inner diameter portion of the sleeve 50 and rotating therein; A thrust plate (90) disposed at a lower end of the shaft (30) to seal one side of the sleeve (50); And a hub (10) having a magnet (20) installed to face the stator core (70) on which the coil is wound on an inner side thereof in a cap shape which is opened downwardly, wherein the spindle motor for a hard disk drive comprises: An axial dynamic pressure generating groove 82 for providing dynamic pressure in the axial direction is formed on the lower surface of the shaft 30 or the upper surface of the thrust plate 90 adjacent thereto. The shaft 30 forms a locking jaw 300 protruding to a predetermined size to its outer circumferential surface, and the inner diameter portion of the sleeve 50 into which the shaft 30 is inserted is formed at a portion corresponding to the locking jaw 300. By forming a protrusion stopper 500 protruding outward so as to approach the locking jaw 300 to prevent the shaft 30 from being separated, The lower end of the sleeve 50 to form an oil receiving groove 510 recessed inward in the circumferential direction of the inner diameter portion; spindle structure for a hard disk drive, characterized in that the sleeve is improved. The method of claim 1, The axial dynamic pressure generating groove 82 Spinning motor for hard disk drive with improved sleeve structure, characterized in that the processing using any one of cutting, electrolytic processing and press processing.

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