WO2010134322A1

WO2010134322A1 - Mounting structure, cup-like member, method of forming the cup-like member, and disk drive device

Info

Publication number: WO2010134322A1
Application number: PCT/JP2010/003334
Authority: WO
Inventors: 荻野隆司; 柏木隆
Original assignee: 日本発條株式会社
Priority date: 2009-05-21
Filing date: 2010-05-18
Publication date: 2010-11-25
Also published as: JP2010270840A

Abstract

A mounting structure in which a cup-like member is secured with enhanced adhesion strength and can be manufactured at reduced cost. A mounting structure for adhering and securing a bearing housing (3), which is a press-formed closed-bottomed cup-like member, by fitting the bearing housing (3) in a mounting hole (5), wherein the mounting structure is provided with anchoring recesses (7) formed in the adhesion surface on the outer peripheral surface (3a) of the bearing housing (3), each anchoring recess (7) having protrusions (9) therein or having an edged section (11) at the edge of the anchoring recess (7). The interface area of the adhesion surface can be increased by the anchoring recesses (7), and the interface area within each anchoring recess (7) can be increased by the protrusions (9) in the recess (7) or by the edged section (11) at the edge of the recess (7). When solidified, an adhesive agent (13) engages with the protrusions (9) in the recesses (7) or with the edged sections (11) at the edges of the recesses (7).

Description

Assembly structure, cup-shaped member, molding method thereof, and disk drive device

The present invention relates to an assembly structure provided for a hard disk drive (HDD), a cup-shaped member, a molding method thereof, and a disk drive device.

Recently, some disk drive devices such as HDDs use a hydrodynamic bearing.

FIG. 15 is a cross-sectional view of a main part of a conventional disk drive device. As shown in FIG. 15, the hydrodynamic bearing 101 includes a shaft 103, a substantially cylindrical sleeve 105 through which the shaft 103 is inserted, and an oil 107 filled between the shaft 103 and the sleeve 105. ing.

The outer peripheral surface of the sleeve 105 is attached to the inner peripheral surface of a bearing housing 109 as a cup-shaped member, and the upper end portion of the shaft 103 is attached to the rotor hub 111. A space surrounded by the shaft 103, the sleeve 105, the bearing housing 109, and the rotor / hub 111 is filled with oil 107.

When the shaft 103 rotates with respect to the sleeve 105, the oil held in the minute radial gap generates dynamic pressure between the outer peripheral surface of the shaft 103 and the inner peripheral surface of the sleeve 105, and the radial (radial) direction is increased. Load bearing pressure is generated. Similarly, when the shaft 103 rotates with respect to the sleeve 105, the oil held in the minute axial gap generates dynamic pressure between the upper end surface of the bearing housing 109 and the lower surface of the rotor / hub 111 top plate portion. Thrust (axial direction) load support pressure is generated.

Thus, the rotor hub 111 can be smoothly rotated with respect to the base 113.

The bearing housing 109 of the disk drive device has an assembly structure that is fixed to the mounting hole 115 of the base 113 by adhesion.

FIG. 16 is a schematic side view of the bearing housing schematically showing the outer peripheral surface including the bonding surface of the bearing housing in an enlarged manner. The bearing housing 109 is formed by machining such as turning, and the surface roughness of the outer peripheral surface 109a constituting the bonding surface is set to about Ra = 0.2.

Therefore, the area of the interface with the adhesive can be increased by the chevron-shaped irregularities formed by turning the outer peripheral surface 109a, and the interface strength can be improved.

However, the turning outer peripheral surface 109a, which becomes the bonding surface, does not reduce the area of the inclined surface of the concavo-convex portion due to machining limitations, and the adhesive itself is peeled and broken, and there is a limit to improving the bonding strength. It was.

In particular, in the case of the bearing housing 109, the adhesive strength in the motor rotation direction is required, and there is a problem that peeling failure is likely to occur along the turning direction.

On the other hand, the bearing housing 109, which is a machined product, can be lapped with a lapping material (abrasive) to reduce the surface roughness of the outer peripheral surface 109a to about Ra = 0.02. In addition to the increase in surface roughness, the adhesive strength decreases due to the decrease in surface roughness.

On the other hand, the turning bearing housing 109 is relatively expensive, and it is also desired to press-mold in order to reduce the cost.

However, the press-molded bearing housing is not formed with uneven portions on the outer peripheral surface as in the turning process, and as shown in the comparison graph of the adhesive strength in FIG. There is a problem that the adhesive strength is lowered, and a press-molded bearing housing cannot be employed.

On the other hand, the lateral groove 117 is formed on the outer peripheral surface 109a of the bearing housing 109 as shown in FIG. 18, or the vertical groove 119 is formed on the outer peripheral surface 109a of the bearing housing 109 as shown in FIG. be able to.

In this case, the lateral groove 117 can be formed on the outer peripheral surface 109a of the bearing housing 109 by forming a concentric groove in advance on the surface of the disk-shaped base material and press drawing the base material.

However, if the concentric grooves formed in advance on the surface of the base material are shallow, the grooves disappear by press molding, and if the grooves are deep, the bearing housing 109 is cut by the press molding, so that it is difficult to form the lateral grooves 117 by press molding. It was.

Also, when the vertical groove 119 was press-molded by the same method, the outer diameter tolerance of the bearing housing 109 could not be satisfied.

On the other hand, when the lateral groove 117 and the vertical groove 119 are formed by cutting after the press molding of the bearing housing 109, not only the cost is increased by machining, but also the outer diameter crossing and the roundness are deteriorated.

JP 2007-247726 A JP 2007-14047 A JP 2007-274755 A

The problem to be solved is that the cup-shaped member by turning has a limit in improving the adhesive strength and is relatively expensive, and the press-formed cup-shaped member is relatively inexpensive, but turning It is a point to which adhesive strength falls with respect to this cup-shaped member.

The present invention is an assembly structure in which a press-formed bottomed cup-shaped member is fitted into an attachment hole and bonded and fixed in order to further improve the adhesive strength and reduce the cost. The assembling structure is characterized in that at least the adhesive surface is provided with an anchor concave portion provided with a plurality of convex portions inside the concave portion or provided with an edge portion at the edge of the concave portion to increase the adhesive strength.

The present invention is characterized by a cup-shaped member provided with the anchor recess used in the assembly structure.

The present invention is a molding method of forming a cup-shaped member semi-finished product by drawing a plate material deeper than a specified size by pressing, and pressing the bottom of the cup-shaped member semi-finished product to obtain a cup-shaped member of a specified size, It becomes easier to form anchor recesses.

The present invention is a disk drive device having the above assembly structure, comprising a hydrodynamic bearing that rotatably supports a shaft via a sleeve and a lubricating fluid in a bearing housing attached to a base, and the mounting hole is The disk drive device is characterized in that the cup-shaped member provided on the base is the bearing housing that is bonded and fixed to the mounting hole.

The present invention is an assembly structure in which a press-formed bottomed cup-shaped member is fitted into an attachment hole and bonded and fixed in order to further improve the adhesive strength and reduce the cost. It is an assembly structure in which an anchor recess is provided at least on the bonding surface, with a plurality of protrusions inside the recess or with an edge on the edge of the recess to increase the adhesive strength.

Therefore, the interface area of the adhesion surface can be increased by the anchor recess, and the interface area in the anchor recess can be increased by a plurality of protrusions or edge portions of the recess edges inside the recess.

Moreover, when the adhesive is solidified, it can be engaged with a plurality of convex portions inside the concave portions or edge portions of the concave portion edges.

For this reason, the occurrence of peeling failure to the anchor concave portion of the adhesive is suppressed, and the adhesive strength between the cup-shaped member and the mounting hole can be further improved.

Moreover, since it is a press-formed bottomed cup-shaped member, it can be made cheaper than that by machining such as turning.

The present invention is a cup-shaped member provided with the anchor recess used in the assembly structure.

For this reason, the adhesive strength of the assembly structure can be improved and it can be manufactured at low cost by press molding.

Form of the present invention is to form a cup-shaped member semi-finished product by drawing deeper than the specified size by pressing the plate material, pressurizing the bottom of the cup-shaped member semi-finished product to form a cup-shaped member of the specified size, Easy to form.

For this reason, the cup-shaped member can be provided with an anchor recess having a plurality of protrusions inside the recess or an edge at the edge of the recess to increase the adhesive strength.

The present invention is a disk drive device having the above assembly structure, comprising a hydrodynamic bearing that rotatably supports a shaft via a sleeve and a lubricating fluid in a bearing housing attached to a base, and the mounting hole is The cup-shaped member is the bearing housing that is provided on the base and is bonded and fixed to the mounting hole.

Therefore, the bearing housing of the hydrodynamic bearing can be assembled to the mounting hole of the base with improved adhesive strength.

Moreover, since it is a press-formed bearing housing with a bottom, it can be a disk drive device equipped with a hydrodynamic bearing that is cheaper than that by turning or the like.

It is an expanded sectional view which shows typically the adhesion part of the base of a disk drive provided with a hydrodynamic bearing, and a bearing housing. Example 1 It is the photograph which observed the anchor recessed part of the bearing housing from the radial direction by the magnification 100 with the tool microscope. Example 1 It is the photograph which observed the specific anchor recessed part of the bearing housing by the magnification of 250 with the tool microscope, and rotated 90 degree | times. Example 1 It is the photograph which observed the anchor recessed part of the same location as FIG. 3 of a bearing housing with the magnification of 1200 with the tool microscope, and rotated 90 degree | times. Example 1 It is the photograph which observed the anchor recessed part of the same location as FIG. 3 of a bearing housing by the magnification 3500 with the tool microscope, and rotated 90 degrees. Example 1 It is the photograph which observed the anchor recessed part of the same location as FIG. 3 of a bearing housing from the circumferential direction inclination position by the magnification 3500 with the tool microscope. Example 1 It is an expanded sectional view showing the section of an anchor crevice typically. Example 1 It is the front view which showed the anchor recessed part typically. Example 1 It is a graph which shows the maximum value and minimum value of the width | variety and height of an anchor recessed part. Example 1 It is the photograph which observed the outer peripheral surface of the bearing housing with the tool microscope. (Comparative example) It is the photograph which observed the outer peripheral surface of the bearing housing with the tool microscope. (Comparative example) It is a graph of the measurement result of the surface roughness of a bearing housing. (Example 1, comparative example) It is a graph which shows the relationship between surface roughness and adhesive strength. (Example 1, comparative example) The outline of the molding method of a bearing housing is shown, (a) is a schematic front view of a bearing housing semi-finished product, (b) is a fragmentary sectional view according to the XIVb-XIVb line arrow of (a), (c) is FIG. 4D is a process diagram of forming an anchor recess in the bearing housing, and FIG. 4D is a partial cross-sectional view corresponding to the XIVd-XIVd line arrow in FIG. Example 1 It is principal part sectional drawing of a disk drive device. (Conventional example) It is a side view of the bearing housing which expands and shows the adhesion surface of a bearing housing typically. (Conventional example) It is a comparison graph of adhesive strength. (Conventional example) It is a side view of a bearing housing. (Conventional example) It is a side view of a bearing housing. (Conventional example)

For the purpose of enabling further improvement in adhesive strength and cost reduction, a cup-shaped member with a press-molded anchor recess with multiple protrusions inside the recess or an edge at the edge of the recess to increase the bond strength Formed and realized.

[Assembly structure and cup-shaped member]
FIG. 1 is an enlarged cross-sectional view schematically showing a base of a disk drive device provided with a hydrodynamic bearing and an adhesive portion of a bearing housing. FIG. 1 corresponds to FIG. 15. For example, similarly to FIG. 15, a shaft (not shown) is inserted into a bearing housing 3 attached to the base 1 via a sleeve (not shown) and a lubricating fluid (not shown). 3) is provided with a hydrodynamic bearing (not shown) for rotatably supporting. Therefore, structures not shown in FIG. 1 such as the sleeve refer to FIG.

1, the disk drive device has an assembly structure in which the bearing housing 3 is fitted into an attachment hole 5 provided in the base 1 and is bonded and fixed.

The bearing housing 3 is a bottomed cup-shaped member formed by press-molding a stainless steel plate material. A plurality of anchor recesses 7 are formed on the outer peripheral surface 3 a of the bearing housing 3. The anchor concave portion 7 is formed in a circumferential shape with a random shape. The anchor recess 7 is also formed on the adhesion surface with respect to the mounting hole 5, and has a configuration in which an anchor recess 7 that increases the adhesion strength is provided on at least the adhesion surface of the bearing housing 3 that is a cup-shaped member.

2 to 6 are photographs of the anchor recess 7 of the bearing housing 3 of FIG. 1 observed with a tool microscope while changing the magnification.

FIG. 2 is a photograph of the anchor recess of the bearing housing observed from the radial direction with a tool microscope at a magnification of 100. FIG. 3 is a photograph of a specific anchor recess of the bearing housing observed by a tool microscope at a magnification of 250 and rotated by 90 °. FIG. 4 is a photograph of the anchor recess at the same location as in FIG. 3 of the bearing housing observed by a tool microscope at a magnification of 1200 and rotated by 90 °. FIG. 5 is a photograph of the anchor recess at the same location as in FIG. 3 of the bearing housing observed by a tool microscope at a magnification of 3500 and rotated by 90 °. FIG. 6 is a photograph of the anchor recess at the same location as in FIG. 3 of the bearing housing observed from a circumferentially inclined position with a magnification of 3500 using a tool microscope.

In FIG. 2, the top and bottom of the drawing is the vertical axis direction of the bearing housing 3 of FIG. 3 to 6, the upper and lower sides in the drawing are the circumferential direction of the bearing housing 3 in FIGS. 1 and 2.

FIG. 7 is a schematic cross-sectional view showing the relationship between the anchor recess and the adhesive, based on the observation results of FIGS. The upper and lower sides in FIG. 7 correspond to the upper and lower sides in FIG.

As shown in FIG. 7, the anchor concave portion 7 includes a plurality of convex portions 9 inside the concave portion, and includes an edge portion 11 at the edge of the concave portion. When the bearing housing 3 is fitted into the mounting hole 5 and bonded and fixed by the adhesive 13, the adhesive 13 enters the anchor concave portion 7 and is solidified so as to engage with the convex portion 9 or the edge portion 11.

Thus, when the adhesive 13 enters the anchor recess 7 and solidifies and mechanically couples the bearing housing 3 to the mounting hole 5, the so-called anchor effect can be enhanced by the protrusion 9 or the edge portion 11.

FIG. 8 is a front view schematically showing the anchor recess, and FIG. 9 is a chart showing the maximum and minimum values of the width and height of the anchor recess.

In FIG. 8, the width W and height H of the anchor recess 7 are defined. The width W is the width in the circumferential direction of the outer peripheral surface 3a of the bearing housing 3 in FIG. 1, and the height H is the height in the axial direction of the bearing housing 3 in FIG. FIG. 9 shows the observation results of FIGS.

As shown in FIGS. 8 and 9, the maximum width W (Max) of the anchor recess 7 is 0.192 mm, the minimum width W (Min) is 0.022 mm, the maximum height H (Max) is 0.019 mm, and the minimum height. H (Min) was 0.016 mm.

10 and 11 are photographs of the outer peripheral surface of the bearing housing observed with a tool microscope according to a comparative example. 10 and 11 show a magnification of 100, which corresponds to the observation in FIG.

The bearing housing 3A in FIG. 10 is a machined product by turning, and the bearing housing 3B in FIG. 11 is a pressed product by pressing.

FIG. 12 is a chart of measurement results of the surface roughness Ra of the

bearing housings

3, 3 </ b> A, and 3 </ b> B of FIGS. 2, 10, and 11. In FIG. 12, X represents the surface roughness in the circumferential direction of the

bearing housings

3, 3A, 3B, and Y represents the surface roughness in the axial direction.

As shown in FIG. 12, the surface roughness of X and Y of the bearing housing 3 of Example 1 is equivalent to that of the pressed bearing housing 3B. The surface roughness of X of the bearing housing 3 is equivalent to the bearing housing 3A of the machined product of the comparative example, whereas the surface roughness of Y can be reduced to about 1/10.

The surface roughness of the bearing housing 3 can be set in the range of Ra = 0.05 to 0.1 for both X and Y.

As described above, in the cutting process, the area of the slope of the concavo-convex part is not reduced due to limitations on machining, and peeling failure of the adhesive itself occurs, and there is a limit in improving the adhesive strength.

Also, in the machined product, when the outer diameter of the bearing housing is reduced, the interface area of the slope is reduced, and the breaking strength of the adhesive itself is obtained.

On the other hand, even if the outer diameter of the bearing housing 3 is similarly reduced, the interface area is compared with the machined product by setting the surface roughness by the anchor recess 7 without having a sloped portion like the machined product. Can be bigger.

For this reason, the engaging force also acts on the adhesive strength, and the adhesive strength can be increased compared to the machined product.

FIG. 13 is a graph showing the relationship between surface roughness and adhesive strength.

FIG. 13 shows an example of a surface roughness Ra = 0.04 which is a press product of an example provided with anchor recesses, and a comparative example of a surface roughness Ra = 0.2 of a bearing housing 3A which is a machined product. 1. The adhesive strength of Comparative Example 2 in which the surface roughness Ra = 0.02 is obtained by lapping the surface of the bearing housing 3A, and Comparative Example 3 in which the surface roughness Ra = 0.04 of the bearing housing 3B which is a press product. Indicated.

As shown in FIG. 13, when the adhesive strength of the bearing housing 3A, which is a machined product of Comparative Example 1, is 100%, the adhesive strength of the bearing housing 3B, which is a pressed product of Comparative Example 3, is low in surface roughness. The machined product had an adhesive strength of 80% equivalent to that of Comparative Example 2.

In contrast, even with the same surface roughness as that of the press-processed product of Comparative Example 3, in Example 1, an adhesive strength of 120% was obtained due to the presence of the anchor recess 7.

This is due to the presence of the convex portion 9 or the edge portion 11 of the anchor concave portion 7.
[Bearing housing molding method]
FIG. 14 shows an outline of a method for forming a bearing housing, (a) is a schematic front view of a semifinished bearing housing, (b) is a partial cross-sectional view corresponding to the XIVb-XIVb line arrow of (a), (C) is a process drawing for forming an anchor recess in the bearing housing, and (d) is a partial sectional view corresponding to the XIVd-XIVd line arrow of (c).

By pressing the circular stainless steel plate, it is deep drawn at a rate of about 2-5% of the total length of the specified dimension, and the bearing housing semi-finished product is a cup-shaped member semi-finished product as shown in FIG. 30 is formed. By drawing deeper than the prescribed dimension, a recess 70 extending in the drawing direction is formed on the outer peripheral surface of the bearing housing semi-finished product 30 as shown in FIGS. 14 (a) and 14 (b).

14 (c), the outer peripheral surface of the bearing housing semi-finished product 30 is gripped by the jig 15, and the bottom of the bearing housing semi-finished product 30 is pressurized so as to be repeatedly struck by the hammer member 17.

As a result of this pressurization, a plurality of anchor recesses 7 are formed on the outer peripheral surface as shown in FIGS. 14C and 14D, and the bearing housing 3 which is a cup-shaped member having a specified size is formed. Since the bottom of the bearing housing semi-finished product 30 is repeatedly hit with the hammer member 17 as described above, the anchor recess 7 has a cross-sectional shape that crushes the opening in the drawing direction.

The gripping force with the jig 15 is such that the bearing housing 3 does not spread to the outer diameter side when hit with the hammer member 17. The hammer member 17 may be struck at least once and may be mere pressure.

Thus, when the bottom of the bearing housing semi-finished product 30 is pressurized so as to be repeatedly hit by the hammer member 17, the concave portion 70 of FIGS. 14 (a) and 14 (b) is deformed, and FIGS. An anchor recess 7 is formed.
[Effect of Example 1]
The embodiment of the present invention is an assembly structure in which a bearing housing 3 that is a press-formed bottomed cup-like member is fitted and fixed to a mounting hole 5, and is an adhesive surface of the outer peripheral surface 3 a of the bearing housing 3. In addition, there is an assembly structure in which a plurality of convex portions 9 are provided inside the concave portion or an edge portion 11 is provided at the edge of the concave portion to provide an anchor concave portion 7 that increases the adhesive strength.

Therefore, the interface area of the bonding surface can be increased by the anchor recess 7 and the interface area in the anchor recess 7 can be increased by the plurality of protrusions 9 inside the recess or the edge 11 of the recess edge.

Moreover, when the adhesive 13 is solidified, it can be engaged with the plurality of convex portions 9 inside the concave portion or the edge portion 11 of the concave portion edge.

For this reason, generation | occurrence | production of the peeling destruction with respect to the anchor recessed part 7 of the adhesive agent 13 is suppressed, and the further improvement of the adhesive strength of the bearing housing 3 and the attachment hole 5 can be aimed at.

Moreover, since the bottomed bearing housing 3 is press-molded, an inexpensive assembly structure can be obtained as compared with a machined process such as a turning process.

The surface roughness of the bearing housing 3 is Ra = 0.05 to 0.1.

For this reason, it is possible to further improve the adhesive strength as compared with the bearing housing 3A which is a machined product while maintaining the same accuracy as the bearing housing 3B of the conventional press product.

For the assembly structure, the bearing housing 3 provided with the anchor recess 7 is used.

For this reason, the adhesive strength of the assembly structure can be improved, and it can be manufactured at low cost by press molding.

A plate material such as stainless steel is drawn deeper than the specified dimension by pressing to form a bearing housing semi-finished product 30, and the bottom of the bearing housing semi-finished product 30 is repeatedly struck and pressurized to form a bearing housing 3 of the prescribed size.

For this reason, the bearing housing 3 can be provided with an anchor recess 7 having a plurality of protrusions 9 inside the recess or an edge 11 at the edge of the recess to increase the adhesive strength.

The disk drive device having the assembly structure includes a hydrodynamic bearing that rotatably supports a shaft via a sleeve and a lubricating fluid in a bearing housing 3 attached to the base 1, and the mounting hole 5 includes: Provided on the base 1, the bearing housing 3 is bonded and fixed to the mounting hole 5.

Therefore, the bearing housing 3 of the hydrodynamic bearing can be assembled to the mounting hole 5 of the base 1 with improved adhesive strength.

In addition, since the bottomed bearing housing 3 is press-molded, the disk drive device can be provided with a hydrodynamic bearing that is less expensive than that by machining such as turning.
[Others]
The cup-shaped member of the present invention can be applied to other than the bearing housing 3 of the disk drive device, and the adhesive strength with respect to the mounting hole can be improved.

1 Base 3 Bearing housing (cup-shaped member)
5 Mounting hole 7 Anchor recess 30 Bearing housing semi-finished product (cup-shaped member semi-finished product)

Claims

An assembly structure in which a press-molded bottomed cup-shaped member is fitted and fixed in a mounting hole,
At least the adhesive surface of the cup-shaped member is provided with an anchor concave portion provided with a plurality of convex portions inside the concave portion or provided with an edge portion at the concave portion edge to increase the adhesive strength.
Assembly structure characterized by that.
The assembly structure according to claim 1,
The surface roughness of the cup-shaped member is Ra = 0.05 to 0.1.
Assembly structure characterized by that.
A cup-shaped member provided with the anchor recess used in the assembly structure according to claim 1 or 2.
The cup-shaped member according to claim 3,
The plate material is drawn deeper than the specified dimensions by pressing to form a cup-shaped member semi-finished product,
Pressurizing the bottom of the cup-shaped member semi-finished product to form a cup-shaped member of a prescribed size;
A method for forming a cup-shaped member.
A disk drive device comprising the assembly structure according to claim 1 or 2,
A hydrodynamic bearing that rotatably supports the shaft via a sleeve and a lubricating fluid in a bearing housing attached to the base;
The mounting hole is provided in the base,
The cup-shaped member is the bearing housing that is bonded and fixed to the mounting hole.
A disk drive device characterized by that.