JP2003314523A - Nut and bearing unit using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a nut by which simple and sure fastening to an object to be fastened is executed. <P>SOLUTION: The hexagonal nut 3 is constituted so as to be capable of fastening and fixing a fastening object to the object to be fastened. A contact part P1 contacting the object to be fastened is provided to a part near to its outer periphery part and a non-contact part P2 not contacting the object to be fastened is provided to the part near to its inner periphery part. The contact part is formed in a plane shape so as to be capable of directly coming into contact with the object to be fastened and is continuously provided circumferentially along the part near to the outer periphery part of the hexagonal nut. The non-contact part is provided between the contact part and a screw part 5 and is recessed inward at a depth equivalent to a prescribed depth from the contact part in the plane shape. In this case, it is also preferable to gradually taper the non-contact part at a prescribed downward inclination angle toward the center of the hexagonal nut. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a nut for fastening a bearing unit used for a head stack of a hard disk drive (HDD), a pivot unit, a spindle motor or the like to an article to be fastened (for example, a swing arm). Regarding

[0002]

2. Description of the Related Art Conventionally, various fastening nuts have been known as represented by JIS B [nuts] and the like.
The side surface of the nut that contacts the object to be fastened is chamfered only on the outer diameter portion and the screw portion. When a fastening object (for example, a bearing unit) is fastened to a fastened object using such a nut, fastening is performed using the entire nut flat surface excluding the chamfered portion.

[0003]

However, in the conventional fastening method using the nut, the screw shaft center of the nut main body is tilted with respect to the plane of the nut, burrs and burrs caused by chamfering other than the screw portion, and other harmful substances. Poor contact between the nut plane and the object to be fastened (for example, inconsistency in contact plane) due to biting or pinching (for example, dust or dust)
May occur. In this case, it becomes difficult to make a uniform contact state over the entire nut plane perpendicular to the screw axis (the entire plane of 360 °), and it becomes difficult to secure and secure the nut securely. The present invention has been made to solve such a problem, and an object thereof is to provide a nut and a bearing unit using the nut, which are capable of performing simple and reliable fastening to an object to be fastened. It is in.

[0004]

In order to achieve such an object, the present invention relates to a nut for fastening and fixing a fastening object to a fastening object, wherein a portion of the nut near the outer circumference is fastened to the fastening object. A contact portion that comes into contact with an object is provided, and a non-contact portion that is not in contact with the object to be fastened is provided at an inner peripheral portion of the nut. Further, the present invention is directed to a bearing assembly in which a shaft, a plurality of bearings, and metal spacers interposed between the bearings are assembled to each other, and a resin assembly capable of coating along the outer diameter shape of the bearing assembly. In the bearing unit including the sleeve, the bearing unit is provided with a nut for fastening and fixing the bearing unit to the object to be fastened, and the nut has a contact portion that comes into contact with the object to be fastened at the outer peripheral portion thereof. Is provided, and a non-contact portion that is not in contact with the object to be fastened is provided in the inner peripheral portion.

In this case, the contact portion has a planar shape, and the non-contact portion is recessed inward by a predetermined depth from the planar contact portion. The non-contact portion is tapered at a predetermined downward inclination angle toward the center of the nut. The non-contact part is provided between the contact part and the screw part. The downward inclination angle of the tapered non-contact portion is set to approximately 5 °. The contact portion can be provided continuously or intermittently along the outer peripheral portion of the nut. Further, the outer diameter portion of the nut is chamfered at a predetermined angle.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION A nut according to a first embodiment of the present invention will be described below with reference to FIG. In addition, in the description of the present embodiment, a hexagon nut will be described as an example. As shown in FIGS. 1A to 1C, the hexagon nut 3 according to the present embodiment has a fastening object (for example, a bearing as described below) with respect to an article to be fastened (for example, a swing arm as described below). The unit) is configured so that it can be fastened and fixed, and a contact portion P1 that comes into contact with the object to be fastened is provided at a portion near the outer periphery of the unit. A non-contacting non-contacting portion P2 is provided. A screw portion (female screw) 5 is formed in the central portion of the hexagonal nut 3, and a chamfer R of a predetermined angle is applied to the outer diameter portion thereof. In this case, the chamfer angle θr can be set arbitrarily according to the use environment and purpose of use of the hexagon nut 3, but in consideration of durability and strength of the hexagon nut 3, θr = about 15 ° It is preferable to set to. In addition, the hexagon nut 3 of the present embodiment has, as an example, an outer diameter dimension D1 of approximately 11.15 m.
m, the diameter dimension D2 other than the chamfer is set to about 10.5 mm, and the thickness dimension W is set to about 1.5 mm.

The contact portion P1 has a planar shape capable of directly contacting the object to be fastened, and is continuous in the circumferential direction along the outer peripheral portion of the hexagon nut 3 (in the present embodiment, an annular shape). ) Is provided. The area of the planar contact portion P1 (that is, the contact area with the object to be fastened) can be increased or decreased according to the type or surface shape of the object to be fastened. As a method of increasing or decreasing the area of the planar contact portion P1,
For example, the chamfering amount (chamfering area,
The chamfer angle etc.) may be increased or decreased. in this case,
For example, as shown in FIG. 1D, if the area of the planar contact portion P1 is reduced, the contact area of the contact portion P1 with the object to be fastened becomes smaller, and the contactability (groundability) with the object to be fastened is further improved. Can be made. However, it is necessary to secure an area enough to exert a fastening and fixing force sufficient to firmly and stably fasten and fasten the fastened object to the fastened object. The contact portion P1 does not necessarily need to be continuously provided, but it is necessary to secure a certain length in consideration of maintaining durability and strength during nut fastening, preventing nut deformation, and the like.

The non-contact portion P2 is provided between the contact portion P1 and the screw portion 5 (over the contact portion P1 to the screw portion 5) and has a predetermined depth larger than that of the planar contact portion P1. It is formed only inwardly. In this case, the depth of the recess of the non-contact portion P2 is arbitrarily set within a range in which durability and strength of the hexagon nut 3 are not deteriorated, and therefore the numerical value is not particularly limited here. That is, when the fastening object is fastened to the fastened object with the hexagon nut 3, if the contact portion P1 is in contact with the fastened object, the non-contact portion P2 is not in contact with the fastened object. The depth of the recess of the non-contact portion P2 is set so that the state is maintained well.

Further, it is also preferable that the non-contact portion P2 is tapered at a predetermined downward inclination angle toward the center of the hexagon nut 3. In this case, the taper angle θ can be arbitrarily set within a range in which durability and strength of the hexagon nut 3 are not deteriorated. Specifically, if the taper angle θ is set too large, the durability and strength of the hexagon nut 3 may decrease, so it is preferable to set θ = about 5 °.

As described above, according to the hexagonal nut 3 of the present embodiment, since the annular contact portion P1 that comes into contact with the object to be fastened is provided in the outer peripheral portion, the position where the hexagonal nut 3 comes into contact with the object to be fastened. Can be separated from the center (screw portion 5). As a result, the influence of the tilt of the screw shaft center of the hexagon nut 3 can be alleviated more than before. More specifically, the annular contact portion P1 can sufficiently reduce the contact area with the contact portion P1 and thus makes point contact or linear contact with the object to be fastened. Moreover, the contact portion P1 is the center (screw portion 5)
Since it is sufficiently separated in the outer diameter direction from, the influence of tilting on the screw shaft center can be alleviated by several steps as compared with the conventional nut. Therefore, uniform contact can be achieved over the entire nut plane (contact portion P1) perpendicular to the screw axis (the entire plane of 360 °), and stable and more reliable fastening and fixing can be performed.

Further, according to the hexagonal nut 3 of the present embodiment, the chamfered portion R other than the screw portion 5 and the screw portion is provided by providing the non-contact portion P2 which is not in contact with the object to be fastened in the inner peripheral portion. It is possible to almost eliminate the occurrence of burrs and burrs and other harmful substances (for example, dust and dust) that are caught or pinched. More specifically, the non-contact portion P formed by recessing the flat contact portion P1 inward by a predetermined depth.
2 can function as a refuge for burr and burrs and other harmful substances (for example, dust and dust).
As a result, stable and more reliable fastening and fixing can be performed without being caught or caught by burrs and burrs.

Further, the hexagon nut 3 of the present embodiment has
By providing the contact portion P1 and the non-contact portion P2 on both side surfaces thereof, it is possible to exert the effects as described above on any of the side surfaces. In this case, since it is not necessary to check the fastening direction each time the nut is fastened (that is, the fastening can be performed from any side surface), the usability of the nut can be improved.

Next, a nut according to a second embodiment of the present invention will be described with reference to FIG. In this embodiment, an oval nut will be described as an example. Figure 2
As shown in (a) to (d), in the oval nut 3'of the present embodiment, the contact portion P1 is intermittently provided along the outer peripheral portion of the oval nut 3 '. That is, the contact portions P1 are provided at symmetrical positions with respect to the center (screw portion 5) of the oval nut 3 '. In the present embodiment, as an example, two contact portions P1 are arranged to face each other. The oval nut 3'is formed with a flat portion 7 by notching both sides of the two contact portions P1. The two contact portions P are thereby formed into the oval nut 3 '.
It is located near the outer circumference of the.

Further, the chamfer R1 and the chamfer angle .theta.r1 of the outer diameter portion of the oval nut 3'are set arbitrarily in consideration of durability, strength, use environment and purpose of use. Further, chamfers R2 having a predetermined chamfer angle θr2 are provided on the flat portion 7 side of the oval nuts 3 ', respectively, and the chamfer R2 can improve the rotatability of the oval nuts 3'. In this case, the amount of chamfer R2 (area, etc.) and chamfer angle θr2 can be set arbitrarily according to the usage environment and purpose of the oval nut 3 ', but the durability of the oval nut 3' Considering the characteristics and strength, it is particularly preferable to set the chamfer angle θr2 to about 5 °. Note that the other configurations are the same as those of the first
Since it is the same as the embodiment, the same reference numerals are given and the description thereof is omitted.

As described above, according to the present embodiment, the contact area can be further reduced by disposing the two contact portions P1 facing each other at the outer peripheral portion of the oval nut 3 '. As a result, point contact or linear contact is obtained. As a result, it is possible to reduce the influence of tilting on the screw shaft center. Therefore, uniform contact can be achieved over the entire nut plane (contact portion P1) perpendicular to the screw axis (the entire plane of 360 °), and stable and more reliable fastening and fixing can be performed. Furthermore, the flat portion 7 of the oval nut 3 '
By chamfering R2 with the chamfer angle θr2 on the side, the fastening property (nut rotation property) at the time of fastening the oval nut 3 ′ can be further improved. Since the other effects are the same as those of the above-described first embodiment, the description thereof will be omitted.

Specific application examples of the nuts of the above-described first and second embodiments will be described with reference to FIGS. 3 to 5. In this application example, rolling bearings including thrust bearings and radial bearings (ball bearings in the drawing)
It is assumed that a plurality of bearing units (two in the drawing) incorporated in the axial direction are fastened and fixed to an object to be fastened. In this case, the object to be fastened is an arm unit in which a plurality of swing arms 22, 26, 28, 34 described later are stacked, and the fastened object is the bearing unit 1.

FIGS. 3A and 3B and FIGS. 4A and 4B
As shown in FIG. 1, the bearing unit 1 includes a shaft 2, a plurality of bearings 4, 6, and a bearing assembly 1a in which a metal spacer 10 interposed between the bearings is assembled together, and an outer diameter shape of the bearing assembly 1a. And a resin sleeve 8 that can be coated along the inner surface of the resin sleeve 8. The resin sleeve 8 is provided with a sliding portion 8c, a part of which is cut out along the axial direction.

The bearings 4 and 6 are each made of a predetermined metal material (for example, high carbon chrome steel such as stainless steel), and are assembled between the outer ring 12, the inner ring 14, and the outer ring 12 and the inner ring 14. A plurality of rolling elements 16, a retainer 18 that rotatably holds the plurality of rolling elements 16, and a sealing plate (contact type or non-contact type seal or shield) 2
It has 0 and. The shaft 2 is also made of the same metal material as the bearings 4 and 6.

A step portion 10a for holding a plurality of bearings at predetermined intervals is integrally formed on the inner circumference of the metal spacer 10 so as to project in the circumferential direction. The width of the metal spacer 10 in the axial direction is set such that a part of the outer circumference of the outer ring 12 of each bearing 4, 6 is covered when the bearings 4, 6 are in contact with the step portion 10a. There is.

The resin sleeve 8 has a threaded portion 8a formed on one end side in the axial direction and an outward flange portion 8 on the other end side in the axial direction.
b is formed. As a material for forming the resin sleeve 8, it is preferable to use a material having a good outgas characteristic (for example, 66 nylon, GF reinforced 66 nylon) and a material having a small linear expansion coefficient.

The slidable portion 8c of the resin sleeve 8 is formed by cutting out along the axial direction, whereby the resin sleeve 8 is elastic in the directions of arrows S1 and S2 in FIG. 4 (a). It is configured so that it can be deformed.
According to this configuration, for example, in the assembling process of the bearing unit 1 described later, the inner diameter of the resin sleeve 8 can be expanded and elastically deformed by expanding the sliding portion 8c in the directions of the arrows S1 and S2. The resin sleeve 8 can be easily covered along the outer diameter shape of the bearing assembly 1a.

A fitting mechanism is provided on the outer circumference of the metal spacer 10 and the inner circumference of the resin sleeve 8.
The fitting mechanism is formed by digging a spacer protrusion 50 protruding along the outer periphery of the metal spacer 10 and an inner periphery of the resin sleeve 8 so that the spacer protrusion 50 can be fitted. And a sleeve recess 52. According to this configuration, when the resin sleeve 8 is coated on the bearing assembly 1a, the spacer protrusion 50 and the sleeve recess 52 are fitted to each other, whereby the metal spacer 10 is attached to the resin sleeve 8. Can be accurately positioned.

In this application example, the spacer protrusions 50 are formed at the upper and lower ends of the metal spacer 10 in the axial direction, respectively, and the sleeve recesses 52 of the resin sleeve 8 are formed at the positions corresponding thereto. In this case, the recessed portions along the circumferential direction, that is, the circumferential grooves 10c are formed between the respective spacer convex portions 50. As a result, the circumferential groove 10c can prevent axial displacement of the resin sleeve 8 and the metal spacer 10. For example, when the nut 36 is fastened to the threaded portion 8a of the resin sleeve 8 in the assembly process described later, a force that extends in the axial direction acts on the resin sleeve 8, but the circumferential groove 10c should be formed. This prevents the resin sleeve 8 from extending in the axial direction.

Here, FIGS. 3 (a), 3 (b) and 4
The assembly process of the bearing unit 1 will be briefly described with reference to (a) and (b). First, after the bearing 4 is assembled to the shaft 2 by press fitting or adhesion, the metal spacer 10 is attached to the bearing 4.
The outer ring 12 is assembled by light press-fitting or adhesion. At this time, the bearing 4 is applied to the step portion 10a of the metal spacer 10. Subsequently, the remaining bearing 6 is simultaneously assembled to the shaft 2 and the metal spacer 10 and the step portion 10
Apply to a. When assembling the bearing 6, a predetermined preload (localization amount preload, constant pressure preload) is applied by adhesion or press fitting to assemble the bearing assembly 1a. Then, as described above, the slidable portion 8c is moved to the arrow S1,
The bearing unit 1 is completed by expanding in the S2 direction and covering the bearing sleeve 1a with the resin sleeve 8.

Next, FIGS. 3 (a), 3 (b) and 5 (a),
As shown in (b), one thin plate-shaped swing arm 22 having a magnetic head (not shown) attached to its tip is attached to one end of the resin sleeve 8 (the resin sleeve 8 in which the bearing assembly 1a is incorporated) in the axial direction. The outer side is covered and the outer side flange portion 8b on the other end side in the axial direction is abutted. Then, the spacer 24
Is applied to the thin plate-shaped swing arm 22 from the one end in the axial direction of the resin sleeve 8, and then the thin plate-shaped swing arms 26 and 28, which are back-to-back with two sheets, are similarly mounted on the resin sleeve 8. After that, the spacer 32 in which the voice coil 30 is integrated is packaged, and further, one thin plate-shaped swing arm 34 is packaged.

Then, the hexagon nut 3 is inserted through the washer 35.
By fastening (or oval nut 3 ') to the threaded portion 8a of the resin sleeve 8, each thin plate swing arm 22, 26, 28, 34 can be rotated around the shaft 2 by the voice coil 30. Becomes In this process, if the spacers 24, 32 are externally fitted to the resin sleeve 8 by an interference fit, the rigidity of the entire apparatus can be improved. Furthermore, in the process of assembling the bearing unit 1, since the thin plate-shaped swing arms 22, 26, 28, 34 can be easily assembled with the nuts 3, 3 ', subsequent maintenance can be easily performed.

In the above-mentioned application example, the bearing unit 1 is fastened to the arm unit in which a plurality of swing arms are laminated by the nuts 3 and 3 ', but for example, an E block type arm in which the swing arms are integrated. The bearing unit 1 may be fastened to the unit with nuts 3 and 3 '.

As described above, according to this application example, since the contact area can be sufficiently reduced by using the nuts 3 and 3'of the first and second embodiments, the object to be fastened (a plurality of swings) can be made. A point contact or a linear contact is made to the arm unit in which the arms 22, 26, 28, 34 are laminated. Moreover, since the contact portion P1 is sufficiently separated from the center (screw portion 5) in the outer diameter direction, it is possible to reduce the influence of tilting on the screw shaft center. For this reason, uniform contact can be achieved over the entire nut plane (contact portion P1) perpendicular to the screw axis (the entire plane of 360 °), and the object to be fastened (the plurality of swing arms 22, 26, 28, 34). Stacked arm unit)
Stable and reliable fastening and fixing can be achieved.

Further, according to the nuts 3 and 3'of the first and second embodiments, the non-contact portion P2 formed by being recessed inward by a predetermined depth from the planar contact portion P1 has a burr. -It can function as an escape area for burrs and other harmful substances (such as dust and dust). As a result, the object to be fastened (the plurality of swing arms 22, 26, 2) is not caught or pinched due to burrs or burrs.
It is possible to stably and more securely fasten and fasten an arm unit in which 8, 34 are laminated.

Further, according to the nuts 3 and 3'of the first and second embodiments, the contact portion P1 and the non-contact portion P2 are provided on both side surfaces of the nuts 3 and 3 ', respectively. Can be demonstrated. In this case, since it is not necessary to check the fastening direction each time the nut is fastened (that is, fastening can be done from either side),
The usability of the nut for the application example can be improved.

[0031]

According to the present invention, it is possible to realize a nut capable of performing simple and reliable fastening with respect to an object to be fastened and a bearing unit using the nut.

[Brief description of drawings]

1A is a plan view of a hexagon nut according to a first embodiment of the present invention, FIG. 1B is a cross-sectional view taken along line LL in FIG. 1A, and FIG. FIG. 6B is an enlarged view of the arrow Zb portion in FIG. 7B, and FIG. 9D is a plan view of the hexagon nut with the contact area reduced.

2A is a plan view of an oval nut according to a second embodiment of the present invention, FIG. 2B is a sectional view taken along line LL in FIG. 2A, and FIG. Is an enlarged view of an arrow Zc portion of FIG. 9A, and FIG. 8D is an enlarged view of an arrow Zd portion of FIG.

FIG. 3A is an application example of the nuts of the first and second embodiments, and is a configuration diagram in which a fastening object (bearing unit) is fastened and fixed to a fastened object (swing arm). , (B) are plan views of FIG.

FIG. 4A is a diagram showing a process of assembling a fastener (bearing unit), and FIG. 4B is a partial cross-sectional view of the fastener (bearing unit) in an assembled state.

FIG. 5A is a diagram showing a process of fastening an object to be fastened (bearing unit) to an object to be fastened (swing arm) by the nuts of the first and second embodiments, and FIG. 6A and 6B are diagrams showing a state in which a fastened object (bearing unit) is fastened to a fastened object (swing arm) with the nut of the second embodiment.

[Explanation of symbols]

3: Hexagon nut 5: Screw part P1: Contact part P2: Non-contact part

Claims (16)

[Claims] 1. A nut for fastening and fixing a fastened object to a fastened object, wherein a contact portion that comes into contact with the fastened object is provided at a portion near the outer circumference of the nut, and a portion near the inner circumferential portion of the nut. The nut is provided with a non-contact portion that is not in contact with the object to be fastened. 2. The contact portion has a planar shape, and
The nut according to claim 1, wherein the non-contact portion is recessed inward by a predetermined depth from the planar contact portion. 3. The nut according to claim 1 or 2, wherein the non-contact portion is tapered at a predetermined downward inclination angle toward the center of the nut. 4. The nut part is formed with a threaded part in the central part thereof, and the non-contact part is provided between the contact part and the threaded part. Described nut. 5. The nut according to claim 3, wherein the taper non-contact portion has a downward inclination angle set to about 5 °. 6. The contact portion is continuously provided along the outer peripheral portion of the nut.
The nut according to any one of 5. 7. The contact portion is intermittently provided along the outer peripheral portion of the nut.
The nut according to any one of 5. 8. The nut according to claim 1, wherein an outer diameter portion of the nut is chamfered at a predetermined angle. 9. A bearing assembly in which a shaft, a plurality of bearings, and metal spacers interposed between the bearings are assembled to each other, and a resin sleeve capable of being coated along the outer diameter shape of the bearing assembly. In the bearing unit composed of and, the bearing unit includes a nut for fastening and fixing the bearing unit to the object to be fastened. A bearing unit, wherein the bearing unit is provided, and a non-contact portion that is not in contact with the object to be fastened is provided at a portion near the inner circumference thereof. 10. The contact portion has a planar shape, and the non-contact portion is formed so as to be recessed inward by a predetermined depth from the planar contact portion. 9. The bearing unit according to item 9. 11. The bearing unit according to claim 9, wherein the non-contact portion is tapered at a predetermined downward inclination angle toward the center of the nut. 12. The nut part is formed with a threaded part in the central part thereof, and the non-contact part is provided between the contact part and the threaded part. Bearing unit described. 13. The bearing unit according to claim 11, wherein the downward inclination angle of the tapered non-contact portion is set to about 5 °. 14. The contact portion is continuously provided along the outer peripheral portion of the nut.
The bearing unit according to any one of 1 to 13. 15. The contact portion is discontinuously provided along the outer peripheral portion of the nut.
The bearing unit according to any one of 1 to 13. 16. The bearing unit according to claim 9, wherein an outer diameter portion of the nut is chamfered at a predetermined angle.