KR100674855B1 - Manufacturing Method for dynamic pressure bearing and The Manufacturing Device - Google Patents

Abstract

The present invention is applicable to all types and types of dynamic bearings, and relates to a method and apparatus for forming a dynamic pressure generating groove on the inner surface by a simple process.

The present invention comprises the steps of lowering the lower punch, so that the dynamic bearing material is accommodated in the step portion consisting of the upper end and the die; Comprising a plurality of core pieces separated from each other, the core having a hole penetrating up and down in the center thereof is guided by the core holder to be inserted into the hollow portion of the dynamic bearing material; Inserting an upper pin into a hole in a central portion of the core to press the core radially outward so that a predetermined intaglio pattern is formed on an inner circumferential surface of the dynamic bearing material; Raising the upper pin to restore the core radially inward, and then elevating the core to separate it from the dynamic bearing material having a dynamic pressure generating groove having a predetermined negative pattern on an inner circumferential surface thereof; And discharging the dynamic pressure bearing material by raising the lower punch. It provides a dynamic pressure bearing manufacturing method and a manufacturing apparatus comprising the same.

Dynamic bearings, dynamic pressure generating grooves, cores, upper pins, embossed patterns

Description

Manufacturing method and apparatus for manufacturing same dynamic pressure bearing {Manufacturing Method for dynamic pressure bearing and The Manufacturing Device}

1 to 3 show a conventional dynamic pressure generating groove forming method.

4 is a side cross-sectional view of a dynamic bearing manufacturing apparatus according to the present invention.

5 shows in detail the core according to the invention.

6 shows a conceptual diagram of the operation of the core according to the invention.

7 shows embodiments of a core according to the invention.

8A to 8E illustrate a method of manufacturing a hydrodynamic bearing according to the present invention.

* Explanation of symbols for main parts of drawings *

110 ... sintered metal material 120 ... die

130 ... lower punch 140 ... core rod

150 ... lower punch 10 ... dynamic bearing material

20 ... Die 30 ... Lower Punch

40 ... core 41 ... core

41a ... insert 41b ... latch

42 ... hole 43 ... embossed pattern

50 ... core holder 60 ... upper pin

The present invention relates to a method for manufacturing a dynamic bearing and a manufacturing apparatus thereof, and more particularly, in the manufacture of a dynamic bearing can be applied to all the various forms and types of the bearing, it is possible to form a dynamic pressure generating groove on the inner surface in a simple process A manufacturing method and its manufacturing apparatus which exist.

Recently, due to the rapid development of the electric and mechanical industries, a driving device requiring ultra-high rotational performance has been developed.

Such driving devices include a scanning motor of a laser printer, a spindle motor of a hard disk drive, a head driving motor of a VCR, and the like. These motors require high-precision, high-speed rotational performance without shaft shaking or shaft shaking to perform more data retrieval, storage and regeneration in a shorter time.

Accordingly, research and development is being actively conducted for the bearing device that enables the improvement of the rotational performance of the motor as well as the development of the drive motor that rotates stably at high speed.

Generally, the bearings used in the motor are classified into rolling bearings and sliding bearings according to the supporting method.

Rolling bearing is to support the shaft through one or more balls, there is an advantage that can be reduced cost and maintain a large rigidity by using a low-cost ball.

However, such rolling bearings have a problem in that high-speed rotational accuracy cannot be obtained due to the occurrence of play caused by a gap between one or more balls and the inner and outer rings in which the balls are installed.

Sliding bearing support is to support the shaft by forming an oil film through a metal bearing or oil containing fluid, there is a disadvantage of unit price increase, while having the advantage of maintaining a high degree of rotation.

The sliding bearing is formed with a spiral dynamic pressure generating groove for generating a predetermined fluid pressure on either side of the bearing or the supporting member so that the boundary friction acts between the supporting members.

1 to 3 illustrate a conventional method for forming a dynamic pressure generating groove, which will be described below.

First, as shown in FIG. 1, the sintered metal material 110 is placed on a die 120 as an initial state of a process, and the upper punch 150 and the core rod 140 are lowered to form a core rod ( 140 is inserted into the upper punch 150, the core rod 140 is to be inserted into the sintered metal material (110). In this case, a predetermined space T is maintained between the inner circumferential surface of the sintered metal material 110 and the forming mold 141 of the core rod 140.

Next, as shown in FIG. 2, the upper punch 150 and the core rod 140 are further lowered to fit the sintered metal material 110 into the die 120. Then, by applying a pressure toward the lower punch 130, the sintered metal material 110 is pressed in the vertical direction.

As a result, pressure is applied to the sintered metal material 110 from the die 120 and the upper and lower punches 150 and 130, and the inner circumferential surface is pressed against the forming mold 141 of the core rod 140. As a result, the shape of the mold 141 is transferred to the inner circumferential surface of the sintered metal material 110 to form a groove.

Finally, as shown in FIG. 3, the die 120 is lowered while supporting the restrained state of the up and down direction of the sintered metal material 110, and the sintered metal material 110 is removed from the die 120. The core rod 140 and the upper punch 150 are raised to separate the core rod 140 from the inner circumferential surface of the sintered metal material 110. When the sintered metal material 110 is separated from the die 120, the sintered metal material 110 may have a spring back, so that the inner diameter thereof is enlarged so as not to collapse the groove.

However, the conventional dynamic pressure generating groove forming method has a problem that cannot be applied to various kinds or forms of dynamic bearings.

In addition, it is possible to apply only to a material having a high strain rate, such as a sintered metal bearing, and even if there is no spring back as much as the core rod can be separated after molding, there is a problem that cannot be applied.

In addition to the above method, a conventional method of forming a dynamic pressure generating groove includes a method of forming a dynamic pressure generating groove by etching, a method of forming a dynamic pressure generating groove by injecting high pressure air containing fine solid particles, and an injection molding method. It has been proposed.

However, these molding methods also had a problem that the operation time is long and the operation cost is relatively high.

Therefore, there has been a need in the art for a method of manufacturing a dynamic pressure bearing and an apparatus thereof capable of preventing the above problems.

The present invention is to solve the conventional problems as described above, it can be applied to various kinds or forms of dynamic bearings, in particular, even if there is no spring back, dynamic pressure bearings that can form a dynamic pressure generating groove precisely An object thereof is to provide a manufacturing method and a manufacturing apparatus thereof.

In order to solve the above object, the present invention provides a pipe-shaped die whose inner peripheral surface corresponds to an outer peripheral surface of a dynamic bearing material; A lower punch provided in contact with an inner circumferential surface of the die and capable of vertical movement, and receiving a dynamic pressure bearing material at an upper end portion and a step portion formed of the die; A predetermined embossed pattern for forming a dynamic pressure generating groove is formed on an outer circumferential surface of the lower insertion part so as to be inserted into the hollow part of the dynamic pressure bearing material, and the upper engaging part having a larger diameter extends radially outward to form a fan shape. A core having a plurality of core pieces separated from each other and having a hole vertically penetrated therethrough; A core holder configured to guide the core to be inserted into the hollow portion of the dynamic bearing material and to cover the engaging portion of the core piece; And a predetermined negative pattern is formed on the inner circumferential surface of the dynamic pressure bearing material by inserting the lower portion of the core into a hole in the center of the core while being inserted into the hollow portion of the dynamic pressure bearing material and pressing the core radially outward. Upper pins to ensure; It provides a dynamic pressure bearing manufacturing apparatus comprising a.

It is preferable that an elastic means is provided between the core and the core holder to provide a restoring force radially inward.

For example, the core may be formed of four core pieces divided by 90 °, and the core may be disposed such that two core pieces divided by 90 ° form 180 ° with each other.

In addition, the present invention in order to solve the above object is in contact with the inner circumferential surface of the pipe-shaped die, by lowering the punch provided to enable the vertical movement, so that the dynamic pressure bearing material is accommodated in the upper end and the step portion consisting of the die ; On the outer circumferential surface of the lower insert portion having a small diameter, a predetermined relief pattern for forming a dynamic pressure generating groove is formed, and the upper engaging portion extends radially outward and has a fan shape and is composed of a plurality of core pieces separated from each other. A core having a hole vertically penetrated at the center thereof to be guided by a core holder to be inserted into a hollow portion of the dynamic bearing material; Inserting an upper pin into a hole in a central portion of the core to press the core radially outward so that a predetermined intaglio pattern is formed on an inner circumferential surface of the dynamic bearing material; Raising the upper pin to restore the core radially inward, and then elevating the core to separate it from the dynamic bearing material having a dynamic pressure generating groove having a predetermined negative pattern on an inner circumferential surface thereof; And discharging the dynamic pressure bearing material by raising the lower punch. It provides a dynamic pressure bearing manufacturing method comprising a.

The present invention may be provided with an elastic means between the core and the core holder, so that when the upper pin is raised from the central hole, the core is spontaneously restored to radially inward.

The core may be composed of four core pieces divided by 90 °, and may be composed of two core pieces divided by 90 °.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Figure 4 is a side cross-sectional view of the dynamic bearing manufacturing apparatus according to the present invention, it will be described as follows.

According to the present invention, a core 40 having a predetermined embossed pattern corresponding to a dynamic pressure generating groove to be formed on the inner circumferential surface of the die 20, the lower punch 30, and the dynamic bearing material 10 in which the dynamic bearing material 10 is accommodated is formed. It may include a core holder 50 for guiding the core 40 and an upper pin 60 that can be inserted into the central hole 42 of the core 40.

In the hydrodynamic bearing manufacturing apparatus according to the present invention as described above, the core 40 is guided to the core holder 50 so as to be inserted into the hollow portion of the dynamic bearing material 10, and in this state the upper pin 60 ) Is inserted into the hole 42 in the center of the core, and the core 40 is pressed radially outward, whereby a predetermined negative pattern, i.e., a dynamic pressure generating groove is formed on the inner circumferential surface of the dynamic bearing material 10. You can do that.

Here, the die 20 has a pipe shape and its inner circumferential surface corresponds to the outer circumferential surface of the dynamic pressure bearing material 10, and the lower punch 30 is provided to be in contact with the inner circumferential surface of the die 20 to allow vertical movement. As illustrated, the dynamic pressure bearing material 10 may be accommodated in the stepped portion formed of the upper end of the lower punch 30 and the die 20.

The core 40 has a predetermined embossed pattern 43 for forming a dynamic pressure generating groove on a lower insert portion outer circumferential surface having a smaller diameter so as to be inserted into the hollow portion of the dynamic bearing material 10, and a large diameter thereof. The upper engaging portion extends radially outward and is composed of a plurality of core pieces having a fan shape, and has a hole 42 in the center thereof.

The core holder 50 is guided so that the core 40 is inserted into the hollow portion of the dynamic bearing material 10, and is formed so that the engaging portion of the core piece is covered.

The upper pin 60 is inserted into the hole 42 in the center of the core 40 in a state where the lower insertion portion of the core 40 is inserted into the hollow portion of the dynamic bearing material 10. 40 by pressing radially outward, a predetermined intaglio pattern is formed on the inner circumferential surface of the dynamic bearing material (10).

 As described above, according to the present invention, a dynamic pressure generating groove can be easily and precisely formed on the inner circumferential surface of the dynamic pressure bearing material, and after the forming of the dynamic pressure generating groove, the upper pin is first raised to restore the core to the radially inner side. By raising the core there is a great effect that can be applied to the material without the spring back phenomenon.

Referring to Figure 5 in more detail the core according to the present invention.

As described above, the core 40 according to the present invention is composed of a plurality of core pieces 41, and the plurality of core pieces 41 are arranged to have a hole 42 in the center thereof.

The core piece 41 has a predetermined embossed pattern 43 as shown on the outer peripheral surface of the lower insertion portion 41a having a smaller diameter, and the upper engaging portion 41b having a larger diameter is radially outward. It expands and has a fan shape.

The embossed pattern 43 of the insertion portion 41a is for forming a dynamic pressure generating groove on the inner circumferential surface of the dynamic bearing material, and the fan-shaped shape of the locking portion 41b has the core 40 of the dynamic bearing material. It is formed to span the core holder for guiding to be inserted into the hollow portion.

At this time, each core piece 41 of the core 40 is at least one end of both ends (head and tail) of the embossed pattern 43, the core piece 41 as shown in Figure 7a When the core 40 is pressed radially outward to form the dynamic pressure generating groove in the inner circumferential surface of the dynamic bearing material 10 by forming the protrusion 41 so as to protrude outward of the outer circumferential surface of the insertion portion 41a, the dynamic pressure generating groove is not broken. It is preferable.

Referring to the operation of the core with reference to a and b of Figure 6 as follows.

The core 40 is composed of a plurality of core pieces 41, and a hole 42 is formed in the center thereof (see FIG. 6A). At this time, an upper pin having an outer diameter larger than the outer diameter of the central hole 42 is inserted into the central hole 42 so that the core pieces 42 press radially outward (arrows) to allow the core piece 41 to be pressed. The embossed pattern formed on the outer circumferential surface of the insertion portion forms an intaglio pattern corresponding to the inner circumferential surface of the dynamic bearing material (see FIG. 6B).

On the other hand, when the intaglio pattern, that is, the dynamic pressure generating groove is formed, the pin is raised and removed, the core pieces 41 are restored to the inner side in the radial direction again, so as to break down the dynamic pressure generating groove formed on the inner circumferential surface of the dynamic bearing. It is possible to raise the core 40 without. At this time, the elastic means is provided between the core 40 and the core holder, it is preferable that the restoring force is provided in the radially inward direction.

Thus, the present invention is to change the inner diameter of the core consisting of a plurality of core pieces, unlike the conventional molding method using the spring back phenomenon of the dynamic bearing material, does not cause a change in the inner diameter of the material does not require a separate post-process There is an advantage.

7A to 7D illustrate embodiments of the core piece of the core, which will be described.

For example, a case in which 12 dynamic pressure generating grooves are to be formed on the inner circumferential surface of the dynamic bearing will be described.

In this case, the dynamic pressure generating groove can be formed by using the core 40 composed of twelve core pieces 41 each having a predetermined relief pattern 43 (see Fig. 7A). At this time, each core piece 41 of the core 40 is at least one end of both ends (head and tail) of the embossed pattern 43, the core piece 41 as shown in Figure 7a When the core 40 is pressed radially outward to form the dynamic pressure generating groove in the inner circumferential surface of the dynamic bearing material 10 by forming the protrusion 41 so as to protrude outward of the outer circumferential surface of the insertion portion 41a, the dynamic pressure generating groove is not broken. It is preferable.

As another example, a core consisting of four core pieces divided by 90 ° may be used to simplify the mold (see FIGS. 7B and 7C).

In this case, as shown in FIG. 7B, the head and tail portions of the predetermined relief pattern 43 may be separated and manufactured on another adjacent core piece 41. This is to prevent the risk of breakage by eliminating the portion under pressure concentrated outside the core piece.

In this case, as shown in FIG. 7C, a pattern may not be formed in the gap between the core pieces.

As another example, as shown in FIG. 7D, two core pieces 41 divided by approximately 90 degrees may use cores arranged to form 180 degrees with each other. At this time, the dynamic pressure generating groove is first formed on the inner circumferential surface of the dynamic bearing material by the two core pieces, and then the core piece is rotated 90 ° so that the dynamic pressure generating groove is formed at the portion where the primary dynamic pressure generating groove is not formed. It is preferable to form it as a tea.

Among these, in the case of Figure 7b and 7c has the advantage that the dynamic pressure generating groove can be made in one process, but in the case of Figure 7b the dynamic pressure generating groove is broken, the dynamic pressure generation in the case of Figure 7c There is a problem that the spacing between the grooves is not constant, that is, the spacing between the dynamic pressure generating grooves corresponding to the respective core pieces becomes uneven. Thus, the method of FIGS. 7A and 7D is more efficient than the method of FIG. 7B or 7C, but the present invention is not limited to the method of FIGS. 7A and 7D.

Referring to Figures 8a to 8e the dynamic pressure bearing manufacturing method according to the present invention configured as described above are as follows.

First, in contact with the inner circumferential surface of the die 20 of the pipe-shaped, the lower punch 30 is provided to enable the vertical movement, so that the dynamic pressure bearing material 10 is accommodated in the upper end and the step portion consisting of the die. .

And as shown in Figure 8a the core 40 is guided to the core holder 50 to be inserted into the hollow portion of the dynamic pressure bearing material 10.

At this time, the core 40 is formed with a predetermined relief pattern for forming a dynamic pressure generating groove on the outer peripheral surface of the lower insertion portion, the upper engaging portion is formed of a plurality of core pieces having a fan shape extending radially outward. desirable.

Next, as shown in FIGS. 8B and 8C, the upper pin 60 is inserted into the hole 42 provided in the center of the core 40. As a result, a predetermined intaglio pattern is formed on the inner circumferential surface of the dynamic bearing material 10 by pressing the core 40 radially outward.

That is, when the upper pin 60 is inserted into the central hole 42 of the core made of the plurality of core pieces, the plurality of core pieces of the core 40 are pressed outward in the radial direction and thus the dynamic bearing material 10 ) It extends to the inner circumference.

As a result, an intaglio pattern corresponding to an embossed pattern of an outer circumferential surface of the lower insert portion of the core 40 is molded on the inner circumferential surface of the dynamic bearing material 10. At this time, each core piece 41 of the core 40 is at least one end of both ends (head and tail) of the embossed pattern 43, the core piece 41 as shown in Figure 7a When the core 40 is pressed radially outward to form the dynamic pressure generating groove in the inner circumferential surface of the dynamic bearing material 10 by forming the protrusion 41 so as to protrude outward of the outer circumferential surface of the insertion portion 41a, the dynamic pressure generating groove is not broken. It is preferable.

After the dynamic pressure generating groove is formed on the inner circumferential surface of the dynamic bearing material 10, as shown in FIGS. 8D and 8E, when the upper pin 60 is raised, the core 40 is restored radially inward. . At this time, it is preferable that an elastic means is provided between the core 40 and the core holder 50 to provide a restoring force in the radially inward direction.

Then, the core 40 is raised and the lower punch 30 is raised to discharge the dynamic pressure bearing material 10.

As described above, the present invention increases the diameter of the outer circumferential surface of the core 40 by increasing the pin 60 first after the formation of the dynamic pressure generating groove, thereby increasing the core 40. There is an advantage that does not affect the inner diameter of the dynamic bearing material 10 without breaking the dynamic pressure generating groove.

In addition, the manufacturing method according to the present invention can be applied regardless of various types or forms of dynamic bearings, in particular, there is an advantage that can be applied even when there is no spring back.

The above has been described in detail with reference to the present invention, which is illustrative and does not limit the present invention.

Dynamic pressure bearing manufacturing method and manufacturing apparatus according to the present invention can be applied regardless of various types or forms of dynamic bearings, in particular, there is an effect that can be applied even when there is no spring back.

In addition, according to the present invention there is no interference does not occur in the inner diameter of the dynamic bearing material, there is an effect that does not require a separate post-process.

In addition to the present invention, not only can the dynamic pressure generating groove be precisely formed, but also the operation is simple and the operation time can be reduced, and the operation cost is relatively inexpensive.

Claims (6)

A die having a pipe shape whose inner circumferential surface corresponds to an outer circumferential surface of a dynamic bearing material; A lower punch provided in contact with an inner circumferential surface of the die and capable of vertical movement, and for receiving a dynamic bearing material at an upper end portion and a step portion formed of the die; A predetermined embossed pattern for forming a dynamic pressure generating groove is formed on the outer peripheral surface of the lower insert portion to be inserted into the hollow portion of the dynamic bearing material, and the upper engaging portion having a larger diameter extends radially outward to form a fan shape. A core having a plurality of core pieces separated from each other and having a hole vertically penetrated therethrough; A core holder configured to guide the core to be inserted into the hollow portion of the dynamic bearing material and to cover the engaging portion of the core piece; And The lower portion of the core is inserted into the hole in the center of the core in the state inserted into the hollow portion of the dynamic bearing material, by pressing the core radially outward, so that a predetermined negative pattern is formed on the inner peripheral surface of the dynamic bearing material An upper pin; Dynamic bearing manufacturing apparatus comprising a. The method of claim 1, And a resilient means provided between the core and the core holder to provide a restoring force radially inward. The method of claim 1, The core is a dynamic bearing manufacturing apparatus, characterized in that consisting of four core pieces divided by 90 °. Contacting a pipe-shaped die inner circumferential surface and lowering a lower punch provided to allow vertical movement, such that a dynamic pressure bearing material is accommodated at an upper end portion and a step portion formed of the die; On the outer circumferential surface of the lower insertion portion having a smaller diameter, a predetermined relief pattern for forming a dynamic pressure generating groove is formed, and the upper engaging portion extends radially outward and has a fan shape and is composed of a plurality of core pieces separated from each other. A core having a hole vertically penetrated at a central portion thereof to be guided by a core holder to be inserted into a hollow portion of the dynamic bearing material; Inserting an upper pin into a hole in a central portion of the core to press the core radially outward so that a predetermined intaglio pattern is formed on an inner circumferential surface of the dynamic bearing material; Raising the upper pin to restore the core radially inward, and then elevating the core to separate it from the dynamic bearing material having a dynamic pressure generating groove having a predetermined negative pattern on an inner circumferential surface thereof; And Discharging the dynamic pressure bearing material by raising the lower punch; Dynamic bearing manufacturing method comprising a. The method of claim 4, wherein Elastic means is provided between the core and the core holder, so that when the upper pin is raised from the central hole, the core is spontaneously restored to radially inward. The method of claim 4, wherein The core is a dynamic bearing manufacturing method, characterized in that consisting of four core pieces divided by 90 °.

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