JP2006316915A - Bearing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive and small bearing device with high rigidity and lubricity, and superior sealing performance. <P>SOLUTION: The bearing device is provided with a rolling bearing supporting a swing arm 20 so as to be turnable with respect to a spindle 14, and the rolling bearing is provided with bearing rings (inner rings 2 and 4, and an outer ring 6) arranged facing one another so as to relatively turn, and a plurality of rolling elements 8 incorporated between the bearing rings. The inner ring is comprised of two bearing ring components divided in an axial direction, and raceway grooves 2g and 4g with mutually the same curvature are formed on each bearing ring component. By mutually combining each raceway groove, a Gothic arch like raceway groove is positioned facing an outer ring raceway groove 6g. A line L1 of action connecting points of the contact of one raceway groove 2g, the rolling element 8, and the outer ring raceway groove, and a line L2 of action connecting points of the contact of the other raceway groove 4g, the rolling element, and the outer ring raceway groove cross each other at a predetermined contact angle with respect to the spindle. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a bearing device that is used, for example, in a portion that swings at a high speed, and particularly to a bearing device for a swing arm provided in a hard disk drive device (HDD device).

  Conventionally, in various OA (Office Automation) devices such as a computer (PC) and a video recorder, various bearing devices are used for the swing arm of the HDD device. For example, the bearing device shown in Patent Document 1 is provided with a pair of rolling bearings that rotatably support a swing arm with respect to a support shaft, and each rolling bearing is disposed so as to be relatively rotatable. An inner ring and an outer ring, a plurality of rolling elements (balls) that are rotatably assembled between the inner and outer rings, and a sealing plate disposed between the inner and outer rings on both sides of the bearing are provided.

  However, in rolling bearings using balls as rolling elements, the number of balls and the ball diameter incorporated between the inner and outer rings are limited, and there is a limit to increasing the rigidity of the bearing. In this case, for example, it is possible to increase the rigidity of the bearing by applying a shoulder ball bearing in which one of the race grooves of the inner ring or the outer ring is scraped off and increasing the number of balls.

  By the way, the shoulder and ball bearings may be provided with “capping allowance” for preventing the inner ring or the outer ring from being loosened. In this case, the bearing (sealing plate) is subjected to a high-frequency heat fitting process. . In such a bearing, since it is necessary to use a cage formed of a material excellent in high-temperature durability (for example, a phenol material), the manufacturing cost of the bearing device increases.

At present, HDD devices are also becoming more compact, and as a response to this, it has high rigidity and at the same time has excellent sealing performance while maintaining constant lubricity over a long period of time. Therefore, development of an inexpensive small bearing device is desired.
JP-A-2005-90592

  Accordingly, an object of the present invention is to provide a low-priced and small-sized bearing device having high rigidity and excellent lubricity and sealing performance.

  In order to achieve such an object, the present invention is a bearing device for a swing arm provided in a hard disk drive device, and the bearing device is a rolling device that rotatably supports the swing arm with respect to a support shaft. A bearing is provided, and the rolling bearing includes a bearing ring disposed so as to be relatively rotatable and a plurality of rolling elements that are rotatably incorporated between the bearing rings. Each track ring structure is formed with two track grooves having the same curvature, and by combining these track grooves with each other, a Gothic arch shape is formed. The raceway groove of the other raceway is positioned opposite to the raceway groove of the other raceway, and a line of action connecting the contact points of the raceway groove of one raceway ring and the rolling element with the raceway groove of the other raceway ring, and The other race ring A working line connecting the contact points mutually the raceway groove and the rolling element and the other race of the raceway grooves of adult intersect at a predetermined contact angle with the support shaft.

In the present invention, the following configuration can be added.
A concave groove is formed in the raceway groove of the other raceway which is not divided. Further, a step is formed on the peripheral surface in which each raceway groove is formed in each raceway structure of one raceway. Further, the step is configured as a margin for the tip of the sealing plate disposed between the races. Further, the step is configured as a margin for the inner diameter portion of the cage. Further, a dimensional difference is provided between the side surface of one of the race rings and the side surface of the other race ring, and a sealing body is attached to the side surface of one of the race rings.

  Here, when there is a dimensional difference between the side surface of one raceway ring and the side surface of the other raceway ring, a plurality of rolling bearings are arranged in the axial direction and attached to the support shaft to apply preload, and the other raceway ring Secure the housing or E block to the In addition, when a plurality of rolling bearings with no dimensional difference between the side surface of one bearing ring and the side surface of the other bearing ring are mounted on the support shaft in the axial direction, a spacer is interposed between any of the bearing rings. Insert the preload and fix the housing or E block to the other race.

  According to the present invention, it is possible to realize a low-priced and compact bearing device having high rigidity and excellent lubricity and sealing performance.

  The bearing device of the present invention will be described below with reference to the accompanying drawings. Note that the present invention assumes a bearing device for a swing arm provided in the HDD device, and an embodiment of the bearing device will be described with reference to the accompanying drawings.

FIG. 1A shows a configuration example of a bearing device according to an embodiment of the present invention.
The bearing device of the present embodiment includes an inner ring 2, 4 and an outer ring 6 that are opposed to each other so as to be relatively rotatable, a plurality of rolling elements (balls) 8 that are rotatably incorporated between the inner and outer rings, and each rolling element. (Ball) 8 is provided with a cage 10 formed with a plurality of pockets 10p for rotatably holding one by one and a sealing plate 12 disposed between inner and outer rings on both sides of the bearing. The outer ring 6 is fitted into a housing 16 (or a swing arm (not shown)). According to such a configuration, the housing 16 (swing arm) can be rotated with respect to the support shaft 14 by the relative rotation of the inner and outer rings.

In this configuration example, as an example of the cage 10 in the drawing, a crown-shaped cage 10 having an opening (not shown) for inserting the rolling element (ball) 8 into the pocket 10p is illustrated on one side. As an example, a bearing shield in which the base end (outer diameter portion 12e) is fixed to the inner peripheral surface 6s of the outer ring 6 and the distal end (inner diameter portion 12t) is not in contact with the outer peripheral surfaces 2s and 4s of the inner rings 2 and 4 and has a narrow clearance. 12 is illustrated.
Note that the cage 10 and the sealing plate 12 are examples, and other cages (for example, mating cage) and sealing plates (for example, contact or non-contact type bearing seals) can be applied. Moreover, as a material of the cage | basket 10, it is possible to apply arbitrary materials, such as a metal and resin, according to the intended purpose and use environment of a bearing apparatus.

  The inner rings 2, 4 are composed of two inner ring components 2, 4 divided in the axial direction, and two raceway grooves 2g, formed on the outer peripheral surfaces 2s, 4s of the inner ring components 2, 4 respectively. 4g has the same curvature. By combining these raceway grooves 2g and 4g with each other, a gothic arch-like raceway groove (generally referred to as an inner ring raceway groove G) is formed into one raceway groove 6g formed on the inner peripheral surface 6s of the outer ring 6. (Hereinafter, referred to as outer ring raceway groove 6g). In this case, since the two inner ring components 2, 4 are externally fitted to the support shaft 14 in a state where they are separated at the top of the Gothic arch, the rolling elements (balls) 8 are the two of the inner ring components 2, 4 respectively. It is rotatably assembled between the inner ring raceway groove G and the outer ring raceway groove 6g with the two raceway grooves 2g and 4g sandwiched from both sides.

  Here, a process for fitting a rolling bearing between the support shaft 14 and the housing 16 will be briefly described. For example, a retainer in a state where a plurality of rolling elements (balls) 8 are held after one inner ring constituting body 2 is fitted onto the support shaft 14 and its side surface 2m is brought into contact with the flange 14f of the support shaft 14. 10 is mounted on the support shaft 14 together with the outer ring 6, and each rolling element (ball) 8 is positioned between the raceway groove 2 g (hereinafter referred to as one raceway groove 2 g) of one inner ring constituting body 2 and the outer ring raceway groove 6 g. . In this state, the other inner ring constituting body 4 is press-fitted into the support shaft 14, and its raceway groove 4 g (hereinafter referred to as the other raceway groove 4 g) is brought into contact with a rolling element (ball) 8 and the outer ring 6 is brought into contact with the housing 16. Fit inside. Then, a predetermined preload is applied to the rolling bearing by applying a pressing force to the side surface 4 m of the other inner ring constituting body 4. In such a process, the number of balls incorporated between the inner and outer rings can be increased as compared with the deep groove type ball bearing.

  In such a state in which the preload is applied, the rolling elements (balls) 8 are maintained in a state where they contact each other between the inner ring raceway groove G and the outer ring raceway groove 6g. In this state, an action line L1 (hereinafter, one action line L1) connecting the contact points of one raceway groove 2g, the rolling element (ball) 8 and the outer ring raceway groove 6g, and the other raceway groove 4g and the rolling contact point. An action line L2 (hereinafter, the other action line L2) connecting the contact points of the moving body (ball) 8 and the outer ring raceway groove 6g intersects the support shaft 14 at a predetermined contact angle. In this case, as the contact angle increases, the bearing load capacity of the axial load can be improved. Conversely, as the contact angle decreases, the bearing load capacity of the radial load can be improved. Note that which load capacity is to be improved is arbitrarily selected according to the use environment and purpose of use of the bearing device, and therefore the contact angle is not particularly limited here.

  As described above, according to the present embodiment, the conventional ball bearing and the internal specifications (for example, the curvature of the inner ring raceway groove G and the outer ring raceway groove 6g, the bearing radial internal clearance, the ball diameter, the number of balls, and the center of the rolling elements are compared. If the diameters of the connected virtual circles (PCD) are the same, one product can achieve the rigidity (double the rigidity) of two conventional products. Moreover, since the number of balls can be increased as compared with the conventional product, the rigidity added with the increased number of balls can be further added. That is, the rigidity of the present product can be obtained as (2 times the increase in the number of balls compared to the conventional product) × 2 times the rigidity.

  Furthermore, according to the present embodiment, both action lines L1 and L2 intersect the support shaft 14 at a predetermined contact angle, so that the load capacity of the axial load and the radial load is simultaneously improved with one rolling bearing. be able to. For this reason, for example, as shown in FIG. 1B, in the configuration in which two rolling bearings are externally mounted on the support shaft 14 and the swing arm 20 is fixed to the outer ring 6 via the E block 18, the support shaft 14 and Even if the axial length of the E block 18 is shortened, the swing arm 20 can be stably supported with high rotational accuracy. Thereby, the HDD device can be made compact.

  In addition, this invention is not limited to embodiment mentioned above, It can change as follows. In the description of each modification, the same reference numerals are given to the same components as those in the above-described embodiment, and the description thereof is omitted.

  As a first modification, for example, as shown in FIG. 1A, a concave groove 22 may be formed in the outer ring raceway groove 6g of the outer ring 6 that is not divided along the circumferential direction. In this case, the concave groove 22 is preferably formed on the bottom surface (deepest part) of the outer ring raceway groove 6g. The groove 22 can be formed continuously or intermittently along the circumferential direction, and the depth and shape of the groove 22 can be arbitrarily set. By forming the concave groove 22 in this way, the lubricant (for example, grease, oil) enclosed in the bearing can be stored in the concave groove 22, so that the outer ring raceway groove 6 g and the rolling elements (balls) 8. The lubricant can be supplied over a long period of time. As a result, since the lubricity of the rolling bearing can be kept constant over a long period of time, it is possible to extend the life of the bearing.

  As a second modification, for example, as shown in FIG. 2A, steps 2d and 4d may be formed on the outer peripheral surfaces 2s and 4s of the inner rings 2 and 4 (inner ring components 2 and 4). In the drawing, as an example, the steps 2d and 4d are formed closer to the side surfaces 2m and 4m. By forming such steps 2d and 4d, the distance between the outer peripheral surfaces 2s and 4s of the inner ring components 2 and 4 from the raceway grooves 2g and 4g to the side surfaces 2m and 4m by the height of the steps 2d and 4d. Can be lengthened. This makes it possible to delay the time for the lubricant to travel to the side surfaces 2m and 4m. In other words, it is possible to increase the time for which the enclosed lubricant remains in the bearing. As a result, since the lubricity of the rolling bearing can be kept constant over a long period of time, it is possible to extend the life of the bearing. The height and position of the steps 2d and 4d are set to optimum values according to, for example, the thickness of the inner rings 2 and 4 (inner ring constituent bodies 2 and 4) and the size and type of the rolling bearings. Not limited.

  Further, the steps 2d and 4d can be configured as “baring allowance” with respect to the tip (inner diameter portion 12t) of the sealing plate (bearing shield) 12, and these steps 2d and 4d are set as “baring allowance”. As a result, the inner ring 12t can restrict the axial movement of the inner ring (inner ring constituting bodies 2, 4), so that the inner ring (inner ring constituting bodies 2, 4) can be prevented from being scattered.

  Furthermore, as a third modification, for example, as shown in FIG. 2B, for example, the step 2d of the steps 2d and 4d can be configured as a “bare allowance” for the inner diameter portion 10n of the cage 10. . In this case, the position of the step 2d is set closer to the rolling element (ball) 8, and the inner diameter portion 10n of the cage 10 is protruded in the direction of the outer peripheral surface 2s of one inner ring constituting body 2. Thereby, the movement of the axial direction of one inner ring structure 2 can be controlled. Other configurations and effects are the same as those of the second modified example, and thus description thereof is omitted.

Further, as a fourth modification, for example, as shown in FIGS. 3A and 3B, between the side surfaces 2m, 4m of the inner rings 2, 4 (inner ring components 2, 4) and the side surface 6m of the outer ring 6, A dimensional difference may be provided.
In the configuration of FIG. 5A, the side surfaces 2m and 4m of the inner rings 2, 4 (inner ring structural bodies 2, 4) are set to have a width dimension protruding in the axial direction from the side surface 6m of the outer ring 6, and the other inner ring An annular sealing body 24 is attached to the side surface 4 m of the structure 4. Thereby, a labyrinth seal is comprised between the said sealing body 24 and the side surface 6m of the outer ring | wheel 6. FIG. In this case, since the double seal structure is constructed by the sealing plate 12 disposed between the inner and outer rings and the newly installed sealing body 24, the sealing performance can be further improved. Further, for example, the flange 14f of the support shaft 14 is extended to the side surface 6m of the outer ring 6 (not shown), and the extended portion is used as a sealing body 24, and a labyrinth seal is provided between the extended portion and the side surface 6m. May be configured. Thereby, a double seal structure can be constructed on both sides of the bearing.

  On the other hand, in the configuration of FIG. 5B, the side surfaces 2m and 4m of the inner rings 2 and 4 (inner ring components 2 and 4) are set so as to have a width dimension that is more immersed in the axial direction than the side surface 6m of the outer ring 6. An annular sealing body 24 is attached to the side surface 6 m of 6. Thereby, a labyrinth seal is comprised between the said sealing body 24 and the side surface 4m of the other inner ring | wheel structure body 4. As shown in FIG. In this case, since the double seal structure is constructed by the sealing plate 12 disposed between the inner and outer rings and the newly installed sealing body 24, the sealing performance can be further improved.

  By newly mounting the sealing body 24 in this manner, the sealing plate 12 is not necessary, and therefore it is not necessary to secure a space for arranging the sealing plate 12 in the bearing. In this case, it is possible to reduce the number of parts by eliminating the sealing plate 12, and as a result, the manufacturing cost of the apparatus can be reduced. Furthermore, since the bearing width can be reduced, the bearing device can be downsized in the axial direction. Accordingly, even when two rolling bearings are externally mounted on the support shaft 14 as shown in FIG. 1B, for example, the HDD device can be made compact by applying the configuration of this modification. As the sealing body 24, any member can be applied as long as it can prevent leakage of the lubricant and intrusion of foreign matters (for example, water and dust). For example, a thin plate-like annular body may be applied, or a seal or a shield may be applied.

  As a fifth modification, for example, as shown in FIGS. 4A and 4B, two rolling bearings are externally mounted on the support shaft 14, and a swing arm 20 is attached to the outer ring 6 via an E block 18. Assume a fixed configuration. In addition, the same figure (a) shows the structural example of a bearing apparatus in case there exists a dimensional difference between the side surfaces 2m and 4m of the inner ring | wheels 2 and 4 (inner ring structure 2 and 4), and the side surface 6m of the outer ring | wheel 6. FIG. 4B shows a configuration example in the case where there is no dimensional difference.

  As an example in FIG. 2A, there are two rolling bearings in which the side surfaces 2m, 4m of the inner rings 2, 4 (inner ring components 2, 4) are set to have a width dimension that protrudes in the axial direction from the side surface 6m of the outer ring 6. It is attached to the support shaft 14. In this case, an axial pressing force Fp is applied to the inner ring component 4 in a state where the side surfaces 2m and 4m of the inner rings 2, 4 (inner ring components 2, 4) adjacent in the axial direction are in contact with each other. Thus, a predetermined preload can be applied to the two rolling bearings.

  In FIG. 2B, as an example, two rolling bearings having no dimensional difference between the side surfaces 2m, 4m of the inner rings 2, 4 (inner ring components 2, 4) and the side surface 6m of the outer ring 6 are mounted on the support shaft 14. Has been. In this case, the axial pressure Fp is applied to the inner ring component 4 with the spacer 26 interposed between the side surfaces 2m and 4m of the inner rings 2, 4 (inner ring components 2, 4) adjacent in the axial direction. By applying the above, a predetermined preload can be applied to the two rolling bearings.

  As described above, according to the fifth modification, the conventional product incorporating two bearings and the internal specifications (for example, the curvature of the inner ring raceway groove G and the outer ring raceway groove 6g, the bearing radial internal clearance, the ball diameter, the number of balls, When the diameters of virtual circles (PCD) connecting the centers of moving objects are the same, the rigidity of the entire bearing device can be improved by a factor of two. For this reason, it becomes possible to stably support the swing arm 20 with high rotational accuracy.

  In this case, for example, as shown in FIG. 5, assuming a bearing device in which two or more (four in the drawing) rolling bearings are installed by extending the support shaft 14 in the axial direction, for example, the outer ring 6 of two bearings. On the other hand, when the swing arm 20 is fixed via the E block 18, it is possible to independently control the rotation of each E block 18, and even in that case, the swing arm 20 is stably supported with high rotational accuracy. be able to. Thereby, for example, the writing accuracy and writing speed of information on the disc or the reproducing accuracy and reproducing speed of information can be improved. In this case, instead of the E block 18, for example, the housing 16 may be fixed.

  In the above-described embodiment and each modification, the bearing device in which the inner rings 2 and 4 are divided has been described. However, the present invention is not limited to this, and the bearing device in which the outer ring 6 is divided in the axial direction is used. The configuration of the present invention can also be applied. In this case, the same effect can be obtained by applying the configuration of the above-described embodiment and each modification to the outer ring 6. The sealing plate 12 has a base end (outer diameter portion 12 e) fixed to the inner peripheral surface 6 s of the outer ring 6 and a distal end (inner diameter portion 12 t) extending in the direction of the outer peripheral surfaces 2 s and 4 s of the inner rings 2 and 4. However, conversely, the base end may be fixed to the outer peripheral surfaces 2 s and 4 s of the inner rings 2 and 4, and the distal end may be extended in the direction of the inner peripheral surface 6 s of the outer ring 6.

(a) is sectional drawing which expands partially the structural example of the bearing apparatus which concerns on one embodiment of this invention, and a 1st modification, (b) is HDD of the bearing apparatus of the same figure (a). Sectional drawing which shows the structural example integrated in the apparatus. (a) is sectional drawing which expands and partially shows the structural example of the bearing apparatus which concerns on the 2nd modification of this invention, (b) is a structural example of the bearing apparatus which concerns on the 3rd modification of this invention. Sectional drawing which expands and shows a part. It is sectional drawing which expands and partially shows the structural example of the bearing apparatus which concerns on the 4th modification of this invention, (a) is set to the width dimension which the side surface of the inner ring protruded in the axial direction rather than the side surface of the outer ring FIG. 5B is a configuration diagram in which the side surface of the inner ring is set to have a width dimension that is more immersed in the axial direction than the side surface of the outer ring. It is sectional drawing which expands and shows a part of example of a structure of the bearing apparatus which concerns on the 5th modification of this invention, (a) is a bearing in case there exists a dimensional difference between the side surface of an inner ring | wheel, and the side surface of an outer ring | wheel. The block diagram of an apparatus, (b) is a block diagram of a bearing apparatus when there is no dimensional difference between the side surface of an inner ring | wheel and the side surface of an outer ring | wheel. Sectional drawing which shows the structural example which incorporated the bearing apparatus which has two or more rolling bearings in HDD apparatus.

Explanation of symbols

2,4 inner ring
2g, 4g Raceway groove 6 Outer ring 6g Outer raceway groove 8 Rolling element 10 Cage 12 Sealing plate 14 Support shaft 16 Housing 18 E block 20 Swing arm
L1, L2 action line

Claims (8)

A bearing device for a swing arm provided in a hard disk drive device,
The bearing device is provided with a rolling bearing that rotatably supports the swing arm with respect to the support shaft, and the rolling bearing is configured to be capable of rolling between the raceway and the raceway arranged so as to be relatively rotatable. A plurality of incorporated rolling elements,
One bearing ring is composed of two bearing ring components divided in the axial direction, and each bearing ring component is formed with a track groove having the same curvature, and these track grooves are mutually connected. In combination, the Gothic arched raceway groove is positioned opposite the raceway groove of the other raceway,
The line of contact between the raceway groove and rolling element of one raceway ring structure and the contact point of the raceway groove of the other raceway ring, the raceway groove and rolling element of the other raceway ring structure, and the other raceway ring A bearing device characterized in that a line of action connecting contact points with the raceway groove intersects the support shaft at a predetermined contact angle.   The bearing device according to claim 1, wherein a concave groove is formed in the raceway groove of the other non-divided raceway ring.   The bearing device according to claim 1 or 2, wherein each bearing ring structure of one of the bearing rings has a step formed on a circumferential surface where the raceway groove is formed.   The bearing device according to claim 3, wherein the step is configured as a margin for a front end of a sealing plate disposed between the race rings.   The bearing device according to claim 3 or 4, wherein the step is configured as a margin for the inner diameter portion of the cage.   6. A dimensional difference is provided between a side surface of one of the race rings and a side surface of the other race ring, and a sealing body is attached to a side surface of any of the race rings. A bearing device according to claim 1.   A plurality of rolling bearings having a dimensional difference between the side surface of one bearing ring and the side surface of the other bearing ring are arranged in the axial direction and attached to the support shaft to apply preload, and a housing or E block is attached to the other bearing ring. The bearing device according to claim 6, wherein the bearing device is fixed. When mounting a plurality of rolling bearings with no dimensional difference between the side surface of one raceway ring and the side surface of the other raceway in the axial direction, insert a spacer between any of the raceways. 6. A bearing device according to claim 1, wherein a preload is applied and a housing or an E block is fixed to the other race ring.

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