KR101275374B1 - Hydrodynamic bearing assembly and motor including the same - Google Patents

Abstract

The present invention relates to a fluid dynamic bearing assembly and a motor including the same, including a fixed member and a rotating member filled with oil in a bearing gap with the fixed member and rotating relative to the fixed member, the outer surface of the oil being external to the interface. It may include a fluid dynamic bearing assembly having a pumping groove for generating a pumping pressure in the oil interface direction on at least one surface of the members facing each other to form a communication path.

Description

Hydrodynamic bearing assembly and motor including the same

The present invention relates to a fluid dynamic bearing assembly and a motor comprising the same.

A hard disk drive (HDD), which is one of information storage devices, is a device that reproduces data stored on a disk using a read / write head or records data on a disk.

Such a hard disk drive requires a disk driving device capable of driving the disk, and a small motor is used for the disk driving device.

The compact motor uses a fluid dynamic bearing assembly, and oil is interposed between the shaft, which is one of the rotating members of the fluid dynamic bearing assembly, and the sleeve, which is one of the fixing members, to support the shaft by the fluid pressure generated by the oil. .

In addition, a spindle motor employing a fluid dynamic bearing assembly constitutes the sealing portion of the fluid by using the surface tension of the fluid and the capillary phenomenon, and stability of the sealing portion is one of the important factors.

However, when an external shock is applied while the motor is driven and stopped, a phenomenon in which the lubricating fluid, which forms the lubricating fluid interface, is leaked to the outside, resulting in a loss of lubricating fluid, thereby lowering the driving stability of the motor.

The following prior art document has a structure in which a pumping groove is provided at a portion filled with a lubricating fluid, and when the lubricating fluid leaks out of the gas-liquid interface by external force, it is difficult to quickly return the leaked fluid to the inside of the gas-liquid interface.

Japanese Laid-Open Patent JP 2010-286071

The present invention is to solve the above problems to provide a motor that can improve the sealing force of the fluid by having a pumping groove for generating a pumping pressure in the oil interface direction on the outside of the portion where the oil interface is formed.

Fluid hydrodynamic bearing assembly according to an embodiment of the present invention is fixed member; And a rotating member filled with an oil in a bearing gap with the fixing member and relatively rotating to the fixing member, wherein at least one surface of the members facing each other to form a communication path with the outside at the interface of the oil is included. A pumping groove for generating a pumping pressure in the oil interface direction may be provided.

Fluid hydrodynamic bearing assembly according to an embodiment of the present invention includes a sleeve that is provided so that the shaft is rotatably fitted; A hub provided at an upper end of the shaft and having a circumferential wall portion protruding downward; And a stopper provided inside the circumferential wall to limit the floating of the hub and to form an oil interface between an inner surface of the inner diameter direction and an outer surface of the sleeve, and including at least one of the surfaces of the sleeve and the stopper facing each other. Some may be provided with a pumping groove for generating a pumping pressure in the oil interface direction on the surface not filled with oil.

Fluid hydrodynamic bearing assembly according to an embodiment of the present invention includes a sleeve that is provided so that the shaft is rotatably fitted; A thrust plate fixed to the shaft and disposed on an upper surface of the sleeve; And a cap member disposed on the thrust plate and configured to seal an lubricating fluid by forming an oil interface between the thrust plates, wherein at least some of the surfaces of the thrust plate and the cap member facing each other are filled with oil. A pumping groove for generating pumping pressure in the oil interface direction may be provided on a surface not supported.

In the hydrodynamic bearing assembly according to an embodiment of the present invention, the pumping groove may be spiral or threaded.

The motor according to an embodiment of the present invention includes a fixed member and a rotating member filled with oil in a bearing gap with the fixed member and rotating relative to the fixed member, to form a communication path with the outside at the interface of the oil. A fluid dynamic bearing assembly having a pumping groove for generating a pumping pressure in an oil interface direction on at least one surface of the members facing each other; A stator coupled to the fixing member and having a core wound around a coil for generating a rotational driving force; And a hub fixed to the rotating member so as to be rotatable with respect to the stator, and having a magnet facing the coil mounted on one surface thereof.

According to the hydrodynamic bearing assembly and the motor including the same according to the present invention, the pumping groove is formed just outside the portion where the oil interface is formed to generate oil pressure in the oil interface direction so that the oil does not leak to prevent the performance and life of the motor. Can be maximized.

1 is a schematic cross-sectional view showing a motor according to an embodiment of the present invention,
2 is a bottom perspective view of a rotor equipped with a stopper as a member in a motor according to an embodiment of the present invention;
3 is a perspective view of a sleeve that is a member of a motor according to an embodiment of the present invention;
4 is a schematic cross-sectional view showing a motor according to another embodiment of the present invention;
5 is a bottom perspective view of a cap member which is a member in a motor according to another embodiment of the present invention;
6 is a perspective view in which a thrust plate, which is a member of a motor, is mounted on a shaft according to another embodiment of the present invention.

Hereinafter, with reference to the drawings will be described in detail a specific embodiment of the present invention. It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the inventive concept. Other embodiments falling within the scope of the inventive concept may readily be suggested, but are also considered to be within the scope of the present invention.

1 is a schematic cross-sectional view showing a motor according to an embodiment of the present invention, Figure 2 is a bottom perspective view of a rotor equipped with a stopper as a member in a motor according to an embodiment of the present invention, Figure 3 is a present invention Is a perspective view of a sleeve that is one member of a motor according to an embodiment of the present disclosure.

1 to 3, a motor 400 according to an embodiment of the present invention includes a fluid dynamic bearing assembly 100 including a shaft 110 and a sleeve 120, and a rotor including a hub 210. It may include a stator 300 including a core 310 to which the 200 and the coil 320 are wound.

The hydrodynamic bearing assembly 100 may include a shaft 110, a sleeve 120, a stopper 190, and a hub 210, and the hub 210 may be a component constituting the rotor 200 to be described later. At the same time, the fluid dynamic bearing assembly 100 may be configured to constitute.

First, when defining a term for the direction, the axial direction refers to the up and down direction with respect to the shaft 110, as seen in Figure 1, the radially outer and inward direction relative to the shaft 110 relative to the hub It may mean the center direction of the shaft 110 with respect to the outer end direction of the 210 or the outer end of the hub (210).

In addition, in the following description, the rotating member is a rotating member including a shaft 110, a rotor 200 including a hub 210, a magnet 220 mounted thereto, and the fixing member is other than the rotating member. The member may be a member fixed relatively to the rotating member such as a sleeve 120, a stator 300, a base, and the like.

In addition, the communication path with the outside at the interface of the oil means a passage that is connected to the outside of the motor at the oil interface and the air may be allowed to enter the communication path.

The sleeve 120 may support the shaft 110 such that an upper end of the shaft 110 protrudes upward in the axial direction. The sleeve 120 may be formed by sintering Cu—Fe alloy powder or SUS powder.

Here, the shaft 110 is inserted to have a small gap with the shaft hole of the sleeve 120 serves as a bearing gap (C), the bearing gap is filled with oil and the outer diameter of the shaft 110 and the The radial dynamic pressure groove 122 formed in at least one of the inner diameter of the sleeve 120 may smoothly support the rotation of the rotor 200.

The radial dynamic pressure groove 122 is formed on the inner surface of the sleeve 120 which is the inside of the shaft hole of the sleeve 120, when the shaft 110 is rotated the shaft 110 is the sleeve 120 Pressure is formed so as to rotate at a predetermined interval spaced with.

However, the radial dynamic pressure groove 122 is not limited to the inner surface of the sleeve 120 as mentioned above, it is also possible to be provided on the outer diameter portion of the shaft 110, the number is also limited Make sure you don't.

The radial dynamic pressure groove 122 may be any one of a herringbone shape, a spiral shape, and a thread shape, and the shape may be any shape as long as it generates a radial dynamic pressure.

The sleeve 120 has a circulation hole 125 formed to communicate the upper and lower portions of the sleeve 120, so that the pressure of oil in the fluid dynamic bearing assembly 100 can be dispersed to maintain equilibrium. In addition, bubbles, etc. existing in the fluid dynamic bearing assembly 100 may be moved to be discharged by circulation.

Here, the upper end of the sleeve 120 is provided with a locking projection 121 protruding outward in a radial direction so that the above-described stopper 190 is locked to limit the injuries of the shaft 110 and the rotor 200. have.

In addition, the axial lower portion of the sleeve 120 may be coupled to the sleeve 120 while maintaining a gap, and the gap may include a base cover 130 for receiving oil.

The base cover 130 may function as a bearing for receiving oil in a gap between the sleeves 120 and supporting the lower surface of the shaft 110 as itself.

On the other hand, the pumping groove 123 for generating a pumping pressure in the oil interface direction on the surface of the sleeve 120 facing the stopper 190 provided on the circumferential wall portion 230 of the hub 210 to be described later, the oil is not filled ) May be formed. The pumping groove 123 may be provided in a spiral or threaded shape. The pumping groove 123 generates dynamic pressure in the air between the stopper 190 and the sleeve 120 by the rotation of the hub 210 so that the air is joined upwardly (in the oil interface direction) ( To generate pumping pressure).

Since the hub 210 is coupled to the shaft 110 and constitutes the hydrodynamic bearing assembly 100 as a rotating member which rotates in association with the shaft 110, the hub 200 may be configured as follows. It will be described in detail in the rotor (200).

The rotor 200 is a rotating structure rotatably provided with respect to the stator 300, and the hub 210 having an annular magnet 220 having a ring-shaped magnet 220 corresponding to each other at a predetermined interval from the core 310 to be described later on the outer circumferential surface thereof. ) May be included.

In other words, the hub 210 may be a rotating member coupled to the shaft 110 to rotate in conjunction with the shaft 110.

Here, the magnet 220 may be provided as a permanent magnet in which the N pole and the S pole are alternately magnetized in the circumferential direction to generate a magnetic force of a predetermined intensity.

In addition, the hub 210 is a first cylindrical wall portion 212 to be fixed to the upper end of the shaft 110, a disc portion 214 extending radially outward from the end of the first cylindrical wall portion 212, The second cylindrical wall portion 216 may protrude downward from the radially outer end portion of the disc portion 214, and the magnet 220 may be coupled to an inner circumferential surface of the second cylindrical wall portion 216.

The hub 210 may include a main wall portion 230 extending downward in an axial direction so as to correspond to an upper outer portion of the sleeve 120.

Here, the inner side of the circumferential wall 230, a stopper 190 for limiting the rise of the hub 210, and forming an oil interface between the inner diameter direction inner surface and the outer surface of the sleeve 120 to be provided Can be.

In addition, the inner circumferential surface of the stopper 190 may be tapered so that the gap with the outer surface of the sleeve 120 may be widened toward the lower portion in the axial direction to facilitate the sealing of oil. In addition, the outer peripheral surface of the sleeve 120 may be formed to be tapered to facilitate the sealing of oil.

Here, a pumping groove 191 for generating a pumping pressure in an oil interface direction may be formed on a surface of the inner surface of the stopper 190 facing the sleeve 120 that is not filled with oil. The pumping groove 191 may be provided in a spiral or threaded shape. The pumping groove 191 generates a dynamic pressure in the air between the stopper 190 and the sleeve 120 by the rotation of the hub 210 so that the air is joined upward (axially in the oil interface direction) ( To generate pumping pressure).

On the other hand, the circumferential wall portion 230 may be provided with a stepped portion 231 to allow the stopper 190 to be seated on the stepped portion 231.

The stator 300 may include a coil 320, a core 310, and a base member 330.

In other words, the stator 300 may be a fixed structure including a coil 320 that generates a predetermined magnitude of electromagnetic force when power is applied and a plurality of cores 310 to which the coil 320 is wound.

The core 310 is fixedly disposed on an upper portion of the base member 330 provided with a printed circuit board (not shown) on which a pattern circuit is printed, and is disposed on an upper surface of the base member 330 corresponding to the winding coil 320. A plurality of coil holes having a predetermined size may be formed to expose the winding coil 320 downward, and the winding coil 320 may be electrically connected to the printed circuit board (not shown) to supply external power. .

The base member 330 may have an outer circumferential surface of the sleeve 120 fixed thereto, and a core 310 in which the coil 320 is wound may be inserted into an inner surface of the base member 330 or the sleeve 120. It can be assembled by applying an adhesive to the outer surface of the.

Figure 4 is a schematic cross-sectional view showing a motor according to another embodiment of the present invention, Figure 5 is a bottom perspective view of a cap member as a member in a motor according to another embodiment of the present invention, Figure 6 is another embodiment of the present invention The thrust plate which is a member of the motor according to the example is a perspective view mounted to the shaft.

4 to 6, the motor 400 ′ including the hydrodynamic bearing assembly 100 ′ according to another embodiment of the present invention includes a thrust plate 130 ′ and a cap member 140 ′. It may include a hydrodynamic bearing assembly 100 ', a stator 300' comprising a core 310 'around which the coil 320' is wound, and a rotor 200 'comprising a rotor case 210'. .

Hereinafter, the configuration will be described in detail.

The hydrodynamic bearing assembly 100 ′ may include a shaft 110 ′, a sleeve 120 ′, a thrust plate 130 ′ and a cap member 140 ′.

First, when defining a term for the direction, the axial direction refers to the up and down direction relative to the shaft 110 ', as shown in Figure 4, the radially outward or inward direction relative to the shaft 110' The center direction of the shaft 110 'means the outer end direction of the rotor 200' or the outer end of the rotor 200 '.

In addition, in the following description, the rotating member rotates including a shaft 110 ', a thrust plate 130', a rotor 200 'including a rotor case 210', a magnet 220 'mounted thereto, and the like. The fixing member may be a member fixed to the rotating member such as a sleeve 120 ', a stator 300', a base, and the like except for the rotating member.

The sleeve 120 'may support the shaft 110' such that an upper end of the shaft 110 'protrudes upward in the axial direction, and forge Cu or Al, or Cu-Fe-based alloy powder or SUS-based powder. It can be formed by sintering.

Here, the shaft 110 'is inserted to have a micro gap with the shaft hole of the sleeve 120', the micro gap is filled with lubricating fluid, and the outer diameter of the shaft 110 'and the sleeve 120' The radial dynamic pressure groove formed in at least one of the inner diameter of the to support the rotation of the rotor 200 'more smoothly.

The radial dynamic pressure groove is formed in the inner surface of the sleeve 120 'which is the inside of the shaft hole of the sleeve 120', and the shaft 110 'is rotated when the shaft 110' is rotated. Pressure is formed to rotate smoothly at a predetermined interval from the inner surface of ').

However, the radial dynamic pressure groove is not limited to being provided on the inner side of the sleeve 120 'as mentioned above, and may be provided on the outer diameter of the shaft 110', and the number is not limited. Let's find out.

The sleeve 120 ′ includes a bypass channel 125 ′ formed to communicate the upper and lower portions of the sleeve 120 ′, thereby balancing the pressure of the lubricating fluid in the fluid dynamic bearing assembly 100 ′ to equilibrate. It may be possible to maintain, and can be moved to discharge the bubbles and the like existing in the fluid dynamic bearing assembly (100 ') by circulation.

Here, the lower portion of the sleeve 120 'may be coupled to the sleeve 120' while maintaining a gap, and the gap may include a cover plate 150 'for receiving lubricating fluid.

The cover plate 150 ′ may function as a bearing for supporting the lower surface of the shaft 110 ′ by receiving lubricating fluid in the gap between the sleeve 120 ′.

Meanwhile, a stepped stepped portion 121 ′ may be provided at an upper end of the sleeve 120 ′ to seat the cap member 140 ′ described below.

In addition, the thrust plate 130 ′ may be rotatably seated on the stepped portion further downward from the stepped portion 121 ′.

The thrust plate 130 ′ is disposed in the axially upper portion of the sleeve 120 ′ and has a hole corresponding to a cross section of the shaft 110 ′ at the center thereof so that the shaft 110 ′ may be inserted into the hole. Can be.

In this case, the thrust plate 130 ′ may be manufactured separately and may be combined with the shaft 110 ′, but may be integrally formed with the shaft 110 ′ from the time of manufacture, and the rotation of the shaft 110 ′ may be performed. In the movement, the shaft 110 rotates along the shaft 110 '.

In addition, a thrust dynamic pressure groove for providing a thrust dynamic pressure to the shaft 110 'may be formed on an upper surface of the thrust plate 130'.

As described above, the thrust dynamic pressure groove is not limited to the upper surface of the thrust plate 130 'and may be formed on the upper surface of the sleeve 120' corresponding to the lower surface of the thrust plate 130 '. .

Meanwhile, a pumping groove 131 ′ for generating a pumping pressure in an oil interface direction may be formed on a surface of the upper surface of the thrust plate 130 ′ facing the cap member 140 ′ to be described below. have. The pumping groove 131 ′ may be provided in a spiral or threaded shape. The pumping groove 131 ′ generates dynamic pressure in the air between the thrust plate 130 ′ and the cap member 140 ′ by the rotation of the thrust plate 130 ′ so that the air is radially outward (oil). In the interface direction) to generate a pumping pressure.

The cap member 140 ′ is a member press-fitted into the stepped portion 121 ′ of the sleeve 120 ′ above the thrust plate 130 ′ to seal the lubricating fluid between the thrust plates 130 ′. Of course, the stepped portion 121 ′ is a portion where the cap member 140 ′ is seated, and the cap member 140 ′ is formed by a standing portion 129 ′ formed outside the stepped portion 121 ′. The radially outer end of may be pressed in.

The cap member 140 ′ may be provided in a tapered shape facing the thrust plate 130 ′ so that the lubricating fluid is sealed. This prevents the lubricating fluid from leaking to the outside when the motor is driven. To take advantage of capillary action and surface tension of lubricating fluid.

Here, a pumping groove 141 ′ for generating a pumping pressure in an oil interface direction may be formed on a surface of the cap member 140 ′ facing the thrust plate 130 ′ without oil filling. The pumping groove 141 ′ may be provided in a spiral or threaded shape. The pumping groove 141 ′ generates dynamic pressure in the air between the thrust plate 130 ′ and the cap member 140 ′ by the rotation of the thrust plate 130 ′ so that the air is radially outward (oil). In the interface direction) to generate a pumping pressure.

The stator 300 'may include a coil 320', a core 330 ', and a base member 310'.

In other words, the stator 300 'may be a fixed structure including a coil 320' for generating a predetermined magnitude of electromagnetic force when power is applied and a plurality of cores 330 'around which the coil 320' is wound. .

The core 330 'is fixedly disposed on an upper portion of the base member 310' provided with a printed circuit board (not shown) on which a pattern circuit is printed, and corresponds to the base member 310 'corresponding to the winding coil 320'. A plurality of coil holes having a predetermined size may be formed through the upper surface of the coil to expose the winding coil 320 'to the bottom, and the winding coil 320' may be provided with an external power supply to the printed circuit board (not shown). ) Can be electrically connected.

The base member 310 ′ may be fixed by pressing an outer circumferential surface of the sleeve 120 ′, and a core 330 ′ around which the coil 320 ′ may be inserted may be inserted into the base member 310 ′. It may be assembled by applying an adhesive to the inner surface or the outer surface of the sleeve (120 ').

 The rotor 200 ′ is a rotating structure rotatably provided with respect to the stator 300 ′, and has a ring-shaped magnet 220 ′ corresponding to each other at predetermined intervals from the core 330 ′ on the outer circumferential surface thereof. It may include a rotor case 210 '.

In addition, the magnet 220 'is provided with a permanent magnet in which the N pole and the S pole are alternately magnetized in the circumferential direction to generate a magnetic force of a predetermined intensity.

Here, the rotor case 210 'is pushed into the upper end of the shaft 110' and fixed to the hub base 212 'and the hub base 212' in the outer diameter direction and bent downward in the axial direction to the It may be made of a magnet support 214 'for supporting the magnet 220'.

As described above, according to the present invention, in a motor using a fluid dynamic bearing assembly structure, in a member facing each other such that an oil interface is formed, a pumping groove is formed at an air side portion at a position where the oil interface is formed. By generating a dynamic pressure by the rotation of one member it is possible to generate a pumping pressure in the oil interface direction.

On the other hand, in the embodiment of the present invention, the shaft (shaft) is shown as an example of a structure that rotates with the rotor, but is not limited to this, the motor of the structure in which the shaft (shaft) is fixed and the sleeve rotates with the rotor is also of the present invention May be included in the implementation.

100: hydrodynamic bearing assembly 110: shaft
120: sleeve 130: cover plate
190: stopper 200: rotor
210: hub 230: main wall portion
300: stator 310: core
320: coil 330: base member
400: motor

Claims (5)

A fixing member; And
And a rotating member filled with oil in a bearing gap with the fixing member and relatively rotating to the fixing member.
And a pumping groove for generating a pumping pressure in an oil interface direction on at least one surface of the members facing each other to form a communication path with the outside at the interface of the oil.
A sleeve provided to rotatably fit the shaft;
A hub provided at an upper end of the shaft and having a circumferential wall portion protruding downward; And
And a stopper provided inside the circumferential wall to limit floating of the hub and to form an oil interface between an inner surface of the inner diameter direction and an outer surface of the sleeve.
At least some of the surfaces of the sleeve and the stopper facing each other is provided with a pumping groove for generating a pumping pressure in the oil interface direction on a surface not filled with oil.
A sleeve provided to rotatably fit the shaft;
A thrust plate fixed to the shaft and disposed on an upper surface of the sleeve; And
And a cap member disposed on the thrust plate and forming an oil interface between the thrust plates to seal the lubricating fluid.
At least some of the surfaces of the thrust plate and the cap member facing each other is provided with a pumping groove for generating a pumping pressure in the oil interface direction on the surface not filled with oil.
4. The method according to any one of claims 1 to 3,
And said pumping groove is spiral or threaded.
At least one of the surfaces of the member facing each other to form a communication path to the outside at the interface of the oil is filled with a fixed member and the bearing member and the rotating member is rotated relative to the fixing member A fluid dynamic bearing assembly having a pumping groove for generating a pumping pressure in an oil interface direction;
A stator coupled to the fixing member and having a core wound around a coil for generating a rotational driving force; And
And a hub fixed to the rotating member so as to be rotatable with respect to the stator, and having a magnet facing the coil mounted on one surface thereof.

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