KR101101607B1 - Electrode for electrolytic machining, electrolytic machining device and spindle motor - Google Patents

Abstract

Spindle motor according to an embodiment of the present invention includes a stator including a core wound around the winding coil to form an electromagnetic force when the power is applied to generate a rotational driving force; A rotor having a hub provided with a magnet facing the winding coil so as to be rotatable with respect to the stator, and a shaft coinciding with the center of rotation of the hub; And a sleeve having a shaft groove accommodating the shaft therein and a protrusion removal groove for removing an unnecessary burr. It may include.

Description

Electrode for electrolytic machining, electrolytic machining and spindle motor comprising the same

The present invention relates to an electrode for electrolytic machining, an electrolytic machining apparatus and a spindle motor including the same, and more particularly to an electrolytic machining electrode for forming a groove in a processed sleeve, an electrolytic machining apparatus and a spindle motor including the same.

In order to generate dynamic pressure in the sleeve supporting the shaft of the spindle motor, the groove is machined to a desired shape and dimensions by cutting, and then grooves are formed through ball rolling on the inner diameter, or the sleeve itself is formed using a sintering press. Grooves are also fabricated using the same shaping process.

In addition, grooves may be formed through electrolytic machining (ECM) on a sleeve that is subjected to general processing or sintering press processing through cutting or the like.

Electrolytic machining is a machining technique in which a desired shape is transferred to a workpiece by dissolving metal by electrical energy while supplying an electrolyte solution between the cathode electrode and the anode workpiece. Such electrolytic machining is used for machining difficult materials and molds of complex shape, and has the advantage of not causing deformation or residual stress of the workpiece.

In order to perform electrolytic processing for forming grooves in the inner diameter of the sleeve, which is a product in which the inner and outer diameters are formed, an electrode is inserted into the inner diameter of the sleeve, which is a workpiece, and an electrolyte solution flows between the electrode and the sleeve. And a jig etc. exist in order to hold the processing position of the said sleeve.

In general, when cutting the sleeve, the bite has good machinability at first, so even if it is mechanically processed like turning or milling, no protruding part is formed on the part, but wear occurs on the bite due to frequent use. As a result, workability is deteriorated, and an unnecessary protrusion is generated in the sleeve.

Therefore, a burr or the like may be formed on the edge portion of the part manufactured by mechanical processing, such as milling or lathe.

In particular, a large number of such protruding portions are generated around the groove, and when the spindle motor rotates, the protruding portions fall to the outside, thereby degrading the rotation of the spindle motor. Therefore, there is a need for techniques to solve the above problem.

SUMMARY OF THE INVENTION An object of the present invention is to provide an electrode for electrolytic machining which removes burrs formed on the sleeve when forming grooves by electrolytic machining on the sleeve, an electrolytic machining apparatus and a spindle motor comprising the same.

Spindle motor according to the present invention includes a stator including a core wound around the winding coil to form an electromagnetic force when the power is applied to generate a rotational driving force; A rotor having a hub provided with a magnet facing the winding coil so as to be rotatable with respect to the stator, and a shaft coinciding with the center of rotation of the hub; And a sleeve having a shaft groove accommodating the shaft therein and a protrusion removal groove for removing an unnecessary burr. It may include.

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In addition, in the spindle motor according to the present invention, the protrusion removing groove may be formed along one end of the radial dynamic groove.

In addition, in the spindle motor according to the present invention, the protrusion removal groove may be formed along both ends of the radial dynamic grooves.

According to the electrode for electrolytic machining according to the present invention and an electrolytic machining apparatus comprising the same, the protrusion is formed in the sleeve so as to remove burrs that are unnecessary when the processing groove is formed in the sleeve by electrolytic machining. The parts can be easily removed, thereby improving part quality.

In general, when the protruding portion is not removed, since the protruding portion is removed when the bearing assembly is rotated, unnecessary particles are generated into the sleeve in which fluid dynamic pressure is generated, thereby deteriorating the characteristics and reliability of the rotation.

However, the electrode for electrolytic machining according to the present invention and the electrolytic machining apparatus including the same have an effect of improving the characteristics and the reliability of the rotation by solving the above problems because the protruding portion is removed when the groove is formed.

Hereinafter, with reference to the drawings will be described in detail a specific embodiment of the present invention. However, the spirit of the present invention is not limited to the embodiments presented, and those skilled in the art who understand the spirit of the present invention may deteriorate other inventions or the present invention by adding, modifying, or deleting other elements within the scope of the same idea. Other embodiments that fall within the scope of the inventive concept may be readily proposed, but they will also be included within the scope of the inventive concept.

In addition, the components with the same functions within the scope of the same idea shown in the drawings of each embodiment will be described using the same reference numerals.

1 is a schematic cross-sectional view showing a spindle motor using a bearing assembly for dynamic pressure fluid according to an embodiment of the present invention.

Briefly described with respect to the spindle motor 100, the spindle motor includes a stator 110, a rotor 120, and a bearing assembly for fluid dynamic pressure.

The stator 110 includes a winding coil 112 that generates a predetermined amount of electric force when power is applied, and a plurality of poles to which at least one of the winding coils 112 is wound extends radially from a center in a radial direction. It is a fixed structure having a core 114.

The core 114 is fixedly disposed on an upper portion of the base 116 on which a substrate (not shown) on which a pattern circuit is printed is provided, and a mounting hole 117 penetrating to a predetermined size is formed on an upper surface of the base 116. Is provided, the mounting hole 117 is provided with a rotation support member for supporting the rotation of the rotor 120.

A plurality of coil holes of a predetermined size may be formed in the upper surface of the base coil 116 and the base 116 corresponding to the winding coil 112, and the winding coil 112 may have an external power source. It is electrically connected with the flexible substrate to be supplied.

In addition, the rotor 120 is a rotational structure rotatably provided with respect to the stator 110, and provided with an annular magnet 122 of the annular shape corresponding to each other at a predetermined interval with the core 114 on the outer peripheral surface With a cup-shaped hub 124, the magnet 122 is provided with a permanent magnet that alternately magnetizes the N pole and the S pole in the circumferential direction to generate a magnetic force of a certain intensity.

The bearing assembly for fluid dynamic pressure is formed at one side of the inner side of the shaft accommodating hole 135 and the sleeve 130 so that the shaft 126 and the shaft 126 are formed to coincide with the rotation center of the rotor 120. The sleeve 130 includes a radial dynamic pressure groove 142, and a protrusion removal groove 134 for removing burrs formed unnecessary on the sleeve 130 or the shaft 126. In this case, the radial dynamic pressure groove 132 may be formed in the outer diameter portion of the shaft 126.

As shown in FIG. 1, the sleeve 130 may be assembled by injecting a lower end of the body having a small outer diameter into the hollow-cylindrical housing 118 assembled to the mounting hole 117 of the stator 110.

The housing 118 is assembled to the inner circumferential surface of the mounting hole 117 by bonding, hot pressing, but is not limited thereto, and may be variously configured.

The sleeve 130 is a rotation support member that forms a sliding surface therebetween in correspondence with each other at a predetermined size with respect to the rotor 120. At this time, the fluid may be filled between the sleeve 130 and the shaft 125, and the friction with the sleeve 130 is reduced during rotation in accordance with the lubricant.

Fluid such as oil or air is supplied into the gap formed between the rotor 120 and the sleeve 130 to be filled in the radial dynamic pressure groove 132, and the radial dynamic pressure groove formed in the sleeve 130 when the motor is driven. The fluid filled in the 132 forms a fluid film under strong pressure, and thus, the sliding surface between the sleeve 130 and the rotor 120 becomes a fluid friction state that minimizes frictional load, thereby making the motor rotate without noise and vibration. The drive is made.

At this time, the fluid does not stagnate between the sleeve 130 and the shaft 125 and moves to a circulation hole formed through the sleeve 130 so that the fluid does not stagnate and circulates. The service life can be extended.

Figure 2 is a schematic cross-sectional view and top view for explaining the mechanical processing state of the sleeve of the bearing support assembly for dynamic pressure fluid according to an embodiment of the present invention.

Referring to FIG. 2, the sleeve 130 is formed in a cylindrical shape through lathe machining or milling, and a shaft accommodating hole 135 for inserting the shaft 125 into the central portion of the sleeve 130 performs mechanical processing. It can be formed through.

In this case, an unnecessarily protruding burr is formed in the sleeve 130, and a protruding portion is formed as follows.

In manufacturing the sleeve 130, first, one cutting surface is formed on the sleeve 130 by using mechanical processing such as lathe machining or milling, and then another cutting surface refracted by the lathe is formed. .

At this time, since each cutting surface is not continuously manufactured using mechanical processing such as lathe machining or milling processing, it is formed discontinuously, so that a protruding portion is mainly generated at the edge where each cutting surface meets.

Therefore, in the present embodiment, the electrode 10 for electrolytic processing is used as a method for removing the protruding portion generated for this reason.

FIG. 3 is a schematic cross-sectional view for describing an electrode for electrolytic machining according to an embodiment of the present invention, and FIG. 4 is a cross-sectional view and a top view for explaining a sleeve formed through the electrolytic machining electrode of FIG. 3.

3 and 4, an electrode 10 for electrolytic machining is in close contact with the upper surface of the sleeve 130 to form a radial dynamic pressure groove 132 in the sleeve 130.

At this time, the radial dynamic pressure groove 132 is processed by the processing groove formed in the sleeve 130 and the electrode processing electrode 10 in contact with the sleeve 130 while the electrolytic processing electrode 10 is supplied and flows therein. The protrusion removal groove 134 is processed by the removal groove.

Therefore, as shown in FIG. 4, a radial dynamic pressure groove 132 having a spiral shape may be formed at an upper end of the sleeve 130. At this time, the protrusion removal groove 134 is formed in the corner portion of the radial dynamic pressure groove 132, and thus the burr generated in the corner portion can be removed.

In the present embodiment, the electrode for electrolytic machining is limited to forming grooves in the sleeve, but it is also applicable to forming grooves in other parts.

5 is a schematic cross-sectional view and a top view for explaining an electrode for electrolytic processing according to an embodiment of the present invention.

Referring to FIG. 5, the electrode 10 for electrolytic processing may include an electrode body 20 and a processing unit 30.

The electrode body 20 forms grooves on one surface of the sleeve 130 through electrolytic processing. In this case, a through hole is formed in the center of the electrode body 20, and the electrolyte may be supplied toward the surface of the sleeve through the through hole.

The processing unit 30 is formed on the front surface of the electrode body 20 and is in contact with the sleeve 130 to form a shape of a groove on the upper surface of the sleeve 130.

In addition, the processing unit 30 has a processing groove 32 having a shape corresponding to the groove in the sleeve 130, and a removal groove 34 for removing an unnecessary protrusion protruding around the processing groove 32. It may be provided.

Specifically, the processing groove 32 is formed to correspond to the spiral (spiral) shape, the removal groove 34 is formed in a ring shape so as to connect one end of the plurality of processing grooves (32).

Therefore, according to the electrode for electrolytic machining according to the present embodiment and the electrolytic machining apparatus including the same, the removal groove 34 together to remove the protruding portion when forming the processing groove 32 through the electrolytic machining in the sleeve 130 together By forming, the protrusions can be easily removed, and the part quality can be improved.

In general, when the protruding portion is not removed, since the protruding portion is removed when the bearing assembly is rotated, unnecessary particles are generated into the sleeve 130 in which fluid dynamic pressure is generated, thereby deteriorating the characteristics and reliability of the rotation.

However, the electrodynamic machining electrode for the fluid dynamic pressure and the electrolytic machining apparatus including the same according to the present embodiment solve the above problems because the protruding portions are removed together as described above in the electrolytic machining for groove formation. There is an effect that the reliability is improved.

6 is a schematic cross-sectional view and a top view for explaining an electrode for electrolytic processing according to another embodiment of the present invention.

Referring to FIG. 6, the electrode 10 for electrolytic processing may include an electrode body 20 and a processing unit 30, and the processing unit 30 may include a processing groove having a shape corresponding to a groove in the sleeve 130. 32 ') and a ring-shaped removal groove 34' which connects both ends of the plurality of processing grooves 32 'to each other.

Therefore, since both corner portions of the radial dynamic pressure groove formed in the sleeve 130 are formed to dent, in this embodiment, the protruding portions formed in the sleeve 130 may be removed together during the electrolytic processing.

7 is a schematic cross-sectional view for describing an electrolytic processing apparatus according to still another embodiment of the present invention.

Referring to FIG. 7, the electrolytic machining apparatus 1 includes an electrolytic solution supply unit 8, an electrolytic machining electrode 10, a power supply unit 3, a recovery unit 4, and a filter unit 5.

The electrolyte supply unit 8 provides the stored electrolyte to the electrode 10 for electrolytic processing. The electrode 10 for electrolytic machining is formed by electrolytic machining a groove for generating a dynamic pressure in the sleeve 130 by using the electrolyte solution provided from the electrolyte supply unit (8).

In order to process the groove in the inner diameter of the sleeve 130, the electrode for electrolytic machining 10 is inserted into the inner diameter of the sleeve 130, the electrolytic machining electrode 10 can support the inner diameter of the sleeve 130 Made of structure.

The power supply unit 3 connects a positive electrode to the sleeve 130 which is the object to be processed, and connects a negative electrode to the electrolytic machining electrode 10 which is a workpiece so that electrolytic machining may occur at the electrolytic machining electrode 10. Do it.

The recovery unit 4 recovers and stores the electrolytic solution electrolytically processed by the electrode 2 for electrolytic processing.

The filter unit 5 functions to filter the electrolyte solution stored in the recovery unit 4 and return it to a state where it can be used again.

The electrode 10 for electrolytic processing used for such an electrolytic processing apparatus is explained in full detail below.

Here, the electrolytic machining electrode 10 is an electrode rod passing through the shaft receiving hole 135 formed in the center of the sleeve 130, radial outer pressure groove to be provided in the sleeve 130 on the outer surface of the electrolytic machining electrode 10; A processing groove 32 having a corresponding shape and a ring-shaped removal groove 34 connecting both ends of the plurality of processing grooves 32 to each other may be included. In this case, the radial dynamic pressure groove may be formed in a herringbon shape.

Through such electrolytic machining, a radial dynamic groove may be formed on the inner surface of the sleeve 130 by the electrolytic machining electrode 10, and the removal groove 34 formed in a ring shape along the top and bottom of the radial dynamic groove may be formed. This can be formed.

Therefore, according to the electrodynamic machining electrode for electrodynamic processing and the electrolytic machining apparatus including the same according to the present embodiment, to remove unnecessary portions generated when forming the processing groove 32 through the electrolytic machining on the sleeve 130. Since the removal grooves 34 are formed together, the protruding portion can be easily removed, and the part quality can be improved.

1 is a schematic cross-sectional view showing a spindle motor using a bearing assembly for dynamic pressure fluid according to an embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view and a top view for explaining a state in which a sleeve of a bearing support assembly for dynamic pressure fluid according to an embodiment of the present invention is processed.

3 is a schematic cross-sectional view for explaining a bearing assembly for a dynamic pressure fluid and an electrode for electrolytic machining according to an embodiment of the present invention.

4 is a cross-sectional view and a top view for explaining a sleeve formed through the electrode for electrolytic processing of FIG.

5 is a schematic cross-sectional view and a top view for explaining an electrode for electrolytic processing according to an embodiment of the present invention.

6 is a schematic cross-sectional view and a top view for explaining an electrode for electrolytic processing according to another embodiment of the present invention.

7 is a schematic cross-sectional view for describing an electrolytic processing apparatus according to still another embodiment of the present invention.

<Description of the symbols for the main parts of the drawings>

1: Electrolytic Processing Device 10: Electrode for Electrolytic Processing

100: spindle motor 20: electrode body

30: processing part 32: processing groove

34: removal groove 130: sleeve

132: radial dynamic pressure groove 134: protrusion removal groove

Claims (12)

delete delete delete delete delete delete delete delete delete A stator including a core to which winding coils which form electromagnetic force when a power is applied to generate rotational driving force are wound; A rotor having a hub provided with a magnet facing the winding coil so as to be rotatable with respect to the stator, and a shaft coinciding with the center of rotation of the hub; And A sleeve having a shaft groove accommodated therein and a protrusion removal groove for removing an unnecessary burr; Spindle motor comprising a. The method of claim 10, And the protrusion removing groove is formed along one end of the radial dynamic grooves. The method of claim 10, The protruding portion removing groove is formed along both ends of the radial dynamic pressure groove.

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