JP5606116B2 - Rolling bearing device and pivot device - Google Patents

Description

  The present invention relates to a rolling bearing device and a pivot device.

  In general, a rolling bearing device used in a magnetic recording device (HDD) is fitted with a rolling bearing having coaxially arranged inner and outer rings, an inner cylinder fitted to the inner ring of the rolling bearing, and an outer ring of the rolling bearing. The inner cylinder and the outer cylinder are supported by a rolling bearing so as to be relatively rotatable (see, for example, Patent Document 1 and Patent Document 2). In the rolling bearing device described in Patent Document 1, a shaft (inner cylinder), an inner ring, a housing (outer cylinder), and an outer ring are joined by an adhesive, respectively. In the rolling bearing device described in Patent Document 2, the shaft and the inner ring are anaerobic. It is joined by a sex adhesive.

Japanese Patent Laid-Open No. 11-182543 JP 2000-346085 A

  However, the anaerobic adhesive has many outgas components and has a disadvantage that the curing time is long and the productivity is low. In addition, when the shaft and the inner ring and the housing and the outer ring are joined together by an adhesive as in the conventional rolling bearing device, the rigidity of the adhesive fluctuates due to a temperature change, and this changes the preload, thereby changing the resonance frequency (resonance) and There is a disadvantage that the torque fluctuates.

  Even in the case of laser welding, when the area of the welding range is increased, there is a problem that the fitting portion is displaced due to thermal contraction when the melted molten portion is cured, and the torque is reduced. Moreover, if the surface roughness of the welded portion is rough, it is difficult to melt evenly, and there is a problem in that the torque is varied due to misalignment and poor bonding at the fitting portion.

  For example, if the resonance is low, the control band is low, which causes inconvenience in reading / writing magnetic information to / from the hard disk, and if the variation in resonance is large, the filter set in the control circuit has a frequency outside the predetermined frequency band. May have resonance. Also, if the torque is low, the positioning error of the magnetic head on the hard disk becomes large, which may cause inconvenience in reading and writing magnetic information.

  The present invention has been made in view of the above-described circumstances, and provides a rolling bearing device and a pivot device that improve productivity and reduce generation of outgas, and prevent occurrence of resonance frequency fluctuation and torque fluctuation. For the purpose.

In order to achieve the above object, the present invention provides the following means.
The present invention relates to a rolling bearing device for swingably supporting a swing arm of a hard disk, and is arranged in an annular space between an inner ring and an outer ring arranged coaxially and an annular space between the inner ring and the outer ring. A plurality of rolling elements arranged at intervals, and two rolling bearings having an outer diameter of 10 mm or less arranged at intervals in the axial direction, and a first fitting fitted to each inner ring of the two rolling bearings Or a second member having a fitting hole for fitting each outer ring, wherein the outer ring or the inner ring is provided so that the swing arm can be mounted, and the inner ring and the first member mating portion and at least one portion of the fitting portion between the second member and the outer ring, at least one of stainless steel of at least one or said outer ring and said second member of said inner ring and said first member It has a surface roughness Ra0.2 or lower rough surface made of, provides a rolling bearing device that is laser welded by weld region having a 200μm smaller diameter by laser irradiation which has been subjected to low-rough surface.

  According to the present invention, if the swing arm is attached to the inner ring or the outer ring, the swing arm can be swingably supported using the two rolling bearings as fulcrums. In this case, anaerobic adhesive is used for joining at least one of the fitting portion between each inner ring and the first member or the fitting portion between each outer ring and the second member by laser welding. As a result, outgassing as in the case of performing can be prevented, and the bonding time can be shortened and the productivity can be improved. Further, it is possible to avoid a preload change caused by a change in the rigidity of the adhesive due to a temperature change as in the case where an adhesive is used, and to stabilize the resonance frequency and torque.

  In addition, laser irradiation is performed by irradiating a low-roughness surface having a surface roughness Ra of 0.2 or less on at least one of the inner ring and the first member or at least one of the outer ring and the second member in the fitting portion. There is little variation in the rate and energy absorption rate, and the low rough surface can be melted almost uniformly. Therefore, it is possible to suppress the variation in the diameter dimension (spot diameter) of the welding range and reduce the joint failure at the fitting portion.

  Further, by making the spot diameter in the welding range smaller than 200 μm, it is possible to reduce thermal contraction when the melted molten part is cured and to suppress the displacement of the fitting part. As a result, when preload is applied to the two rolling bearings, it is possible to prevent the preload from being lost due to the displacement of the fitting portion, and it is possible to obtain a stable torque and resonance.

  In the said invention, it is good also as a diameter dimension of the welding range by the said laser welding being 150-100 micrometers.

  If the spot diameter by laser welding is too small for the gap between the welded materials in the fitting part, the welded materials cannot be joined with a sufficient amount of melting, and the joining strength may not be ensured. is there. By setting the spot diameter by laser welding to 150 to 100 μm, it is possible to suppress misalignment due to thermal contraction of the melted portion and to secure the bonding strength of the fitting portion.

  In the above invention, a spacer portion sandwiched in the axial direction is provided between one of the outer rings or the inner rings, and the other inner ring or the outer ring is relative to the inner ring or the outer ring adjacent in the axial direction. Alternatively, laser welding may be performed on the first member or the second member in a state where the first member or the second member is pressed in the direction of approaching each other.

  With this configuration, a gap corresponding to the length of the spacer portion is formed between the other inner rings or the outer rings by the spacer portion sandwiched between the outer rings or the inner rings. Alternatively, the state in which the preload is applied to the two rolling bearings can be easily and stably maintained by laser welding with the first member or the second member in a state where the outer rings are relatively close to each other in the axial direction. be able to.

  The present invention includes a base member, the swing arm, and the rolling bearing device of the present invention, wherein one of the first member and the second member is fixed to the base member, A pivot device in which the swing arm is attached to an outer ring or the inner ring is provided.

  According to the present invention, with the two rolling bearings of the rolling bearing device, with respect to the base member fixed to the first member or the second member, the swing arm mounted on the outer ring or the inner ring is stabilized with the resonance frequency. It can be swung with torque.

The present invention relates to a rolling bearing device for swingably supporting a swing arm of a hard disk, and is arranged in an annular space between an inner ring and an outer ring arranged coaxially and an annular space between the inner ring and the outer ring. A plurality of rolling elements arranged at intervals, and two rolling bearings having an outer diameter of 10 mm or less arranged at intervals in the axial direction, and a first fitting fitted to each inner ring of the two rolling bearings And a second member having a fitting hole into which the outer rings of the two rolling bearings are fitted, and the first member or the second member is provided so that the swing arm can be attached thereto. At least one of a fitting portion between the inner ring and the first member and a fitting portion between the outer ring and the second member is at least one of the inner ring and the first member or the outer ring and Said second member At least one having a surface roughness Ra0.2 or lower rough surface made of stainless steel material, are laser welded by weld region having a 200μm smaller diameter by laser irradiation which has been subjected to low rough rolling bearing Providing equipment.

  According to the present invention, a plurality of rolling elements roll in an annular space between each inner ring and each outer ring of the two rolling bearings, so that the first member and each outer ring fitted to each inner ring are The fitted second member is relatively rotated about the axis of the two rolling bearings. Therefore, if the swing arm is attached to the first member or the second member, the swing arm can be swingably supported using the two rolling bearings as fulcrums.

  In this case, outgassing can be prevented and bonded by joining at least one of the fitting portion between each inner ring and the first member and the fitting portion between each outer ring and the second member by laser welding. Time can be shortened and productivity can be improved. Further, it is possible to avoid a change in preload due to a change in the rigidity of the adhesive due to a temperature change, and to stabilize the resonance frequency and torque.

  In addition, laser irradiation is performed by irradiating a low-roughness surface having a surface roughness Ra of 0.2 or less on at least one of the inner ring and the first member or at least one of the outer ring and the second member in the fitting portion. There is little variation in the rate and energy absorption rate, and the low rough surface can be melted almost uniformly. Therefore, it is possible to suppress variation in spot diameter and reduce joint failure at the fitting portion.

  Further, by making the spot diameter in the welding range smaller than 200 μm, it is possible to reduce thermal contraction when the melted molten part is cured and to suppress the displacement of the fitting part. As a result, when preload is applied to the two rolling bearings, it is possible to prevent the preload from being lost due to the displacement of the fitting portion, and it is possible to obtain a stable torque and resonance.

In the said invention, it is good also as a diameter dimension of the welding range by the said laser welding being 150-100 micrometers.
By comprising in this way, the position shift by the thermal contraction of a fusion | melting part can be suppressed, and the joining strength of a fitting part can be ensured.

In the above invention, a spacer portion sandwiched in the axial direction is provided between one of the outer rings or the inner rings, and the other inner ring or the outer ring is relative to the inner ring or the outer ring adjacent in the axial direction. Alternatively, laser welding may be performed on the first member or the second member in a state where the first member or the second member is pressed in the direction of approaching each other.
By comprising in this way, the state which applied the pre-load to two rolling bearings can be maintained easily and stably.

  The present invention includes a base member, the swing arm, and the rolling bearing device of the present invention, wherein one of the first member and the second member is fixed to the base member, A pivot device in which the swing arm is mounted on a second member or the first member is provided.

  According to the present invention, the first member and the second member are relatively rotated by the two rolling bearings of the rolling bearing device, so that the base is fixed to the first member or the second member. The swing arm mounted on the other side of the member can be swung with a stable resonance frequency and torque.

  According to the present invention, it is possible to improve productivity and reduce outgas generation, and to prevent the occurrence of resonance frequency fluctuations and torque fluctuations.

It is a longitudinal cross-sectional view of the pivot apparatus which concerns on one Embodiment of this invention. It is a longitudinal cross-sectional view of the rolling bearing apparatus of FIG. It is a longitudinal cross-sectional view of the fitting part of the inner ring | wheel and the shaft before the laser welding of FIG. It is a longitudinal cross-sectional view of the state which laser-welded the fitting part of FIG. It is a top view which shows the welding range of FIG. It is a figure which shows the relationship between the surface roughness of a welding range, and a spot diameter.

Hereinafter, a rolling bearing device and a pivot device according to an embodiment of the present invention will be described with reference to the drawings.
The pivot device 50 according to the present embodiment is used in a hard disk drive device, for example, as shown in FIG. The pivot device 50 includes a base housing (base member) 51, a swing arm 53, and a rolling bearing device 10 that supports the swing arm 53 in a swingable manner with respect to the base housing 51.

A recess 52 for attaching the rolling bearing device 10 is formed on the lower end surface of the base housing 51.
The swing arm 53 has a cylindrical main body 55 having a bearing fitting hole 54 into which the rolling bearing device 10 is fitted, and a plurality of (here, five) arranged in multiple stages along the axial direction of the cylindrical main body 55. Arm portions 57 and a magnetic head (not shown) provided at the tip of each arm portion 57 for writing magnetic information on a hard disk (not shown) and reading recorded magnetic information.

  As shown in FIG. 2, the rolling bearing device 10 is fitted to the first rolling bearing 1 </ b> A and the second rolling bearing 1 </ b> B arranged coaxially with an interval in the axial direction, and the rolling bearings 1 </ b> A and 1 </ b> B. A shaft (first member) 13 and a sleeve (second member) 23 having a fitting hole 25 into which the rolling bearings 1A and 1B are fitted.

  The first rolling bearing 1A includes an inner ring 3a and an outer ring 5a that are arranged coaxially, and a plurality of rolling elements 7 that are built in an annular space between the inner ring 3a and the outer ring 5a with a circumferential interval therebetween. And. The second rolling bearing 1B has the same configuration as that of the first rolling bearing 1A, and includes an inner ring 3b and an outer ring 5b, and a plurality of rolling elements 7. Each rolling element 7 is held so as to be able to roll in a state of being arranged at equal intervals by a retainer (not shown).

  These rolling bearings 1A and 1B have, for example, an outer dimension of about 9.525 mm and an inner diameter of about 6.35 mm. Further, the inner rings 3a and 3b, the outer rings 5a and 5b, and the rolling elements 7 are formed of, for example, a stainless material such as SUS440C, and the component range has 16 to 18 wt% of Cr.

  Deep groove or angular inner ring raceways are provided on the outer peripheral surfaces of the inner rings 3a and 3b, respectively, and deep groove or angular outer ring raceways are provided on the inner peripheral surfaces of the outer rings 5a and 5b, respectively. Further, the inner rings 3a and 3b have a surface roughness (arithmetic average roughness) around the inner peripheral edges 4a and 4b as shown in FIG.

  A shaft 13 is fitted to the inner rings 3a and 3b. As shown in FIGS. 4 and 5, the fitting portions between the inner rings 3a and 3b and the shaft 13 are joined by laser welding in the vicinity of the boundary between the inner peripheral edges 4a and 4b of the inner rings 3a and 3b and the outer peripheral surface of the shaft 13. ing. A symbol W indicates a welding range by laser welding. As a laser used for laser welding, for example, a wavelength of about 1 μm, which is a fundamental wavelength of a Yag laser or a fiber laser, or a wavelength of about 500 μm of a second harmonic is used.

  The center of the welding range W is arranged on a surface having a substantially circular shape and a surface roughness Ra of 0.2 or less, for example, on the inner peripheral edges 4a and 4b of the inner rings 3a and 3b. Further, the welding range W has a diameter of 200 μm or less, for example, a diameter of about 150 to 100 μm. Hereinafter, the center of the welding range W is referred to as “keyhole”, and the diameter of the welding range W is referred to as “spot diameter”. In addition, the fitting part of the inner rings 3a and 3b and the shaft 13 is laser-welded at a plurality of places (for example, three places) with a gap in the circumferential direction by the welding range W having the above spot diameter.

  The outer rings 5a and 5b are fitted in the fitting holes 25 of the sleeve 23, respectively. In these fitting portions, for example, the outer peripheral surfaces of the outer rings 5a and 5b and the inner peripheral surface of the fitting hole 25 are joined by an adhesive. Examples of the adhesive include an anaerobic adhesive and a thermosetting adhesive.

  The shaft 13 is a substantially cylindrical member. For example, a shaft having a diameter of about 6.3 mm or less is used. Moreover, the shaft 13 is formed of, for example, a stainless material such as SUS303, SUS303CU, or SUS420, and the component range of Cr is 12 to 20 wt%.

  One end of the shaft 13 in the axial direction is provided with a flange-like flange portion 15 protruding outward in the radial direction over the entire circumference and a male screw forming protrusion 17 protruding in the axial direction. A screw hole 19 extending in the axial direction is formed at the other end of the shaft 13 in the axial direction.

  The shaft 13 is configured such that the projection 17 is fitted into the recess 52 on the lower end surface of the base housing 51. The shaft 13 is fixed to the upper end surface of the base housing 51 on the rotation axis C by inserting a screw (not shown) into the screw hole 19 from the outside of the base housing 51. .

  The shaft 13 is fitted into the first rolling bearing 1A and the second rolling bearing 1B in order from the flange portion 15 side, and the flange portion 15 is abutted against the end surface of the inner ring 3a of the first rolling bearing 1A. ing. Hereinafter, a fitting portion between the shaft 13 and the inner ring 3a of the first rolling bearing 1A is referred to as a “first fitting portion 29A”, and a fitting portion between the shaft 13 and the inner ring 3b of the second rolling bearing 1B is referred to. This is referred to as “second fitting portion 29B”.

  Further, the inner rings 3a and 3b of the rolling bearings 1A and 1B are joined to the shaft 13 in a state where they are pressed in directions approaching each other. As a result, a preload is applied to the rolling bearings 1A and 1B, and the inner rings 3a and 3b and the outer rings 5a and 5b and the rolling elements 7 are brought into contact with no gap.

  The sleeve 23 is a substantially cylindrical member, and its outer peripheral surface is fitted in the bearing fitting hole 54 of the swing arm 53. The fitting hole 25 of the sleeve 23 is provided with a convex portion (hereinafter referred to as a “spacer portion”) 27 that protrudes inward in the radial direction at substantially the center in the axial direction.

  The fitting hole 25 is fitted with the first rolling bearing 1A on one side in the axial direction and the second rolling bearing 1B on the other side across the spacer portion 27, and the end faces of the outer rings 5a and 5b facing each other. Are abutted against the spacer portion 27. Hereinafter, a fitting portion between the fitting hole 25 and the outer ring 5a of the first rolling bearing 1A is referred to as a “third fitting portion 29C”, and the fitting hole 25 and the outer ring 5b of the second rolling bearing are fitted. The joint portion is referred to as “second fitting portion 29D”.

Hereinafter, a method for manufacturing the rolling bearing device 10 and the pivot device 50 configured as described above will be described.
First, the shaft 13 is fitted to the inner ring 3 a of the first rolling bearing 1 </ b> A, and the end surface of the inner ring 3 a is abutted against the flange portion 15 of the shaft 13. Then, laser light is irradiated to the inner peripheral edge 4a of the end surface opposite to the end surface abutted against the flange portion 15 of the inner ring 3a, and the inner diameter of the inner ring 3a is adjusted so that the spot diameter of the welding range W is about 150 to 100 μm. Laser welding is performed near the boundary between the peripheral edge 4 a and the outer peripheral surface of the shaft 13.

  Here, if the spot diameter in the welding range is too large (for example, if the spot diameter is 200 μm or more), the melting amount of the inner ring 3a and the shaft 13 becomes larger than the melting amount necessary for joining, and the melted molten portion becomes larger. Thermal shrinkage during curing increases. For this reason, the positional deviation between the inner ring 3a and the shaft 13 becomes large and preload may not be applied. Further, when the surface roughness Ra of the laser light irradiation range is 1.6 or more, there are many variations in the reflectance of the laser light and the energy absorptivity, and the laser light cannot be uniformly melted. Therefore, as shown in FIG. 6, even if the set value of the spot diameter in the welding range is limited, the actual spot diameter variation is large, and the possibility of occurrence of poor bonding is increased.

  The rolling bearing device 10 according to the present embodiment irradiates the laser beam so that the keyhole is disposed on the inner peripheral edge 4a of the inner ring 3a having a surface roughness of Ra 0.2 or less. There is little variation in the energy absorption rate, and the periphery of the inner peripheral edge 4a can be melted almost uniformly. Therefore, as shown in FIG. 6, it is possible to suppress the variation in the spot diameter of the welding range and reduce the joint failure at the fitting portion.

  In addition, by setting the spot diameter of the welding range W to about 150 to 100 μm, the inner ring 3 a and the inner ring 3 a The shaft 13 can be joined with a sufficient melting amount to ensure the joining strength.

  Next, an adhesive is applied to the fitting hole 25 of the sleeve 23 or the outer peripheral surface of the outer ring 5b of the second rolling bearing 1B. Then, the outer ring 5 b is fitted into the fitting hole 25, and the end surface of the outer ring 5 b is abutted against the spacer portion 27 of the fitting hole 25.

  Subsequently, an adhesive is applied to the outer peripheral surface of the outer ring 5 a of the first rolling bearing or the fitting hole 25 of the sleeve 23. Then, in a state where the shaft 13 fitted to the first rolling bearing 1A is fixed so that the flange portion 15 faces vertically downward, the sleeve 23 fitted with the second rolling bearing 1B is fitted.

  Specifically, the shaft 13 is fitted to the inner ring 3b of the second rolling bearing 1B fitted into the sleeve 23, and the outer ring 5a of the first rolling bearing 1A fitted with the shaft 13 is fitted to the first rolling bearing 1B. The end portion of the outer ring 5 a is abutted against the spacer portion 27 by being fitted to the fitting portion 29 </ b> A.

In this state, the second fitting portion 29B is joined by laser welding.
Here, a gap corresponding to the length of the spacer portion 27 is formed between the inner rings 3a and 3b by the spacer portion 27 sandwiched between the outer rings 5a and 5b of the rolling bearings 1A and 1B. A preload can be applied to the rolling bearings 1 </ b> A and 1 </ b> B by pressing the inner ring 3 b toward each other.

  In this case, since the inner ring 3a of the first rolling bearing 1A is abutted against the flange portion 15 of the shaft 13, the inner ring 3b of the second rolling bearing 1B is pressed in the axial direction against the inner ring 3a. It is possible to apply a preload to both the rolling bearings 1A and 1B simply by making them.

  Therefore, the inner ring 3b is pressed in the axial direction, the laser beam is irradiated to the inner circumferential edge 4b of the inner ring 3b, and the inner circumferential edge 4b of the inner ring 3b and the shaft 13 so that the spot diameter in the welding range W is about 150 to 100 μm. Laser welding is performed in the vicinity of the boundary with the outer peripheral surface. Thereby, the state in which the preload is applied to the rolling bearings 1A and 1B can be easily maintained.

  Further, in the first fitting portion 29A and the second fitting portion 29B, the positional deviation between the inner rings 3a and 3b and the shaft 13 can be suppressed and can be joined with high accuracy. Accordingly, it is possible to prevent the preload from being lost and to apply a stable preload. Thereby, as shown in FIG. 6, a stable torque and resonance can be obtained.

  Subsequently, when the other third fitting portion 29C and the fourth fitting portion 29D are joined with an adhesive, the rolling bearing device 10 is completed. For example, when an anaerobic adhesive is used as the adhesive, the adhesive is cured by being left for a predetermined time, and the fitting portions 29C and 29D are joined. When a thermosetting adhesive is used as the adhesive, the adhesive is cured by applying predetermined heat, and the fitting portions 29C and 29D are joined.

  In the rolling bearing device 10 manufactured as described above, a plurality of rolling elements 7 roll in an annular space between the inner rings 3a and 3b and the outer rings 5a and 5b of the two rolling bearings 1A and 1B. Thus, the shaft 13 fitted to each inner ring 3a, 3b and the sleeve 23 fitted to each outer ring 5a, 5b are relatively rotated around the axis of the rolling bearing 1A, 1B.

  Then, the swing arm 53 is attached to the sleeve 23, the projection 17 of the shaft 13 is fitted into the recess 52 on the lower end surface of the base housing 51, and the rolling bearing device 10 is fixed. Hereinafter, the operation of the pivot device 50 will be described.

  When a driving unit (not shown) such as a voice coil motor is operated, a swing arm 53 that fits the sleeve 23 against the base housing 51 to which the shaft 13 of the rolling bearing device 10 is fitted causes the rolling bearing device 10 to move. It is swung around the rotation axis C as a fulcrum. Thereby, each magnetic head is reciprocated on each hard disk.

  For example, by operating the swing arm 53 at a high speed, each magnetic head is instantaneously moved to data recorded at a predetermined position on each hard disk, and reading of magnetic information recorded on the hard disk and writing of magnetic information are performed. It can be performed.

  As described above, according to the rolling bearing device 10 and the pivot device 50 according to the present embodiment, by applying laser irradiation to the inner peripheral edges 4a and 4b of the inner rings 3a and 3b having a surface roughness of Ra0.2 or less, While suppressing the variation of the spot diameter of the welding range and making the spot diameter of the welding range smaller than 200 μm, the positional deviation between the inner rings 3a, 3b and the shaft 13 is suppressed, and the fitting portions 29A, 29B are joined accurately. be able to. Thereby, preload loss can be prevented and stable torque and resonance can be obtained.

  Further, compared to the case where all the fitting portions 29A, 29B, 29C, and 29D are joined with an adhesive, the outgas generation is reduced, and the joining time is shortened and the productivity can be improved. In addition, according to laser welding, it is possible to avoid a change in preload due to a change in the rigidity of the adhesive due to a change in temperature as in the case of joining with an adhesive, and to stabilize resonance and torque. Therefore, the swing arm 53 can be swung with stable resonance and torque with respect to the base housing 51.

  In the present embodiment, the inner peripheries 4a and 4b of the inner rings 3a and 3b have a surface roughness Ra of 0.2 or less. However, the inner rings 3a and 3b and the shaft 13 in at least one of the fitting portions. At least one of at least one of the outer rings 5a and 5b and the sleeve 23 has a low rough surface with a surface roughness Ra0, 2 or less, and laser welding is performed so that a keyhole is disposed on the low rough surface. Good. Further, the spot diameter in the welding range by laser welding may be made smaller than 200 μm.

  For example, the surface roughness of the outer peripheral surface of the shaft 13 may be Ra 0.2 or less, and laser welding may be performed so that a keyhole is disposed on the outer peripheral surface of the shaft 13, or the inner peripheral edges of the inner rings 3a and 3b. The surface roughness of both the periphery of 4a, 4b and the outer peripheral surface of the shaft 13 may be set to Ra 0.2 or less, and laser welding may be performed so that a keyhole is disposed near these boundaries.

Further, for example, either one or both of the outer peripheral edges of the outer rings 5a and 5b and the fitting hole of the sleeve 23 have a surface roughness Ra of 0.2 or less, and the surface roughness Ra of 0.2 or less. Laser welding may be performed so that the keyhole is disposed on the surface. In this case, a sleeve that does not include the spacer portion 27 on the inner surface of the fitting hole 25 may be employed as the second member, and a ring-shaped spacer may be sandwiched between the inner rings 3a and 3b of the rolling bearings 1A and 1B. . By doing so, a gap corresponding to the length of the spacer is formed between the outer rings 5a and 5b. Therefore, the rolling bearing is formed by laser welding in a state where the outer rings 5a and 5b are pressed toward each other. The state in which preload is applied to 1A and 1B can be easily and stably maintained.
Moreover, it is good also as joining all the fitting parts 29A, 29B, 29C, and 29D by laser welding, or joining together using laser welding and an adhesive agent.

Moreover, in this embodiment, although three places were laser-welded in the circumferential direction of fitting part 29A, 29B, for example, two or less places of the circumferential direction or four or more places of the circumferential direction are laser-welded. It is good as well.
In this embodiment, the swing arm 53 is attached to the sleeve 23 and the shaft 13 is fixed to the base housing 51. For example, the swing arm is attached to the shaft 13 and the sleeve 23 is fixed to the base member. It is good to do. Further, for example, the outer rings 5a and 5b may be directly fitted into the bearing fitting holes of the swing arm without using the sleeve 23. Further, for example, when the sleeve 23 is fixed to the base member, the swing arm may be directly fitted to the inner rings 3 a and 3 b without using the shaft 13.

  In the present embodiment, the rolling bearings 1A and 1B having an outer dimension of about 9.525 mm and an inner diameter of about 6.35 mm have been described as examples. However, as the rolling bearing, for example, the outer dimension is about 8 mm. Examples include those having an inner diameter of about 5 mm, those having an outer dimension of about 7 mm and an inner diameter of about 4 mm, and those having an outer dimension of about 5 mm and an inner diameter of about 2.5 mm.

Further, the present embodiment may be modified as follows.
For example, in the same fitting part 29A, 29B, 29C, 29D, it is good also as carrying out laser welding further by the welding range from which a spot diameter differs in the position different in the circumferential direction from the first laser welding. For example, first, the inner rings 3a and 3b or the outer rings 5a and 5b are laser-welded with a spot diameter of laser light that does not cause displacement due to thermal contraction, and then the same position as the first welding position or the first welding position May be laser-welded at a position shifted in the circumferential direction with a spot diameter (laser power higher than the initial laser power) larger than the spot diameter by the initial laser welding.

  By doing in this way, a fitting part can be accurately fixed by the first laser welding, maintaining the shape of inner ring 3a, 3b or outer ring 5a, 5b substantially. Next, when laser welding is performed with high laser power, even when a force that relatively changes the inner rings 3a and 3b and the shaft 13 or the outer rings 5a and 5b and the sleeve 23 acts due to thermal contraction of the welded portion. Further, it is possible to join with high joining strength while suppressing the displacement of the fitting portion by the fixing force of the welded part by the first laser welding.

DESCRIPTION OF SYMBOLS 1A 1st rolling bearing 1B 2nd rolling bearing 3a, 3b Inner ring 5a, 5b Outer ring 7 Rolling body 10 Rolling bearing apparatus 13 Shaft (1st member)
23 Sleeve (second member)
25 Fitting hole 50 Pivot device 51 Base housing (base member)
53 Swing arm

Claims (8)

A rolling bearing device for swingably supporting a swing arm of a hard disk,
Coaxially arranged inner and outer rings, and a plurality of rolling elements arranged circumferentially in an annular space between the inner ring and the outer ring, and arranged outside in an axial direction. Two rolling bearings with a diameter of 10 mm or less ,
A first member fitted to each inner ring of the two rolling bearings, or a second member having a fitting hole for fitting each outer ring;
The outer ring or the inner ring is provided so that the swing arm can be mounted,
At least one of the fitting portion between the inner ring and the first member and the fitting portion between the outer ring and the second member is at least one of the inner ring and the first member or the outer ring and the first member. At least one of the members 2 has a low roughness surface made of stainless steel and has a surface roughness Ra of 0.2 or less, and is laser welded by a laser beam applied to the low roughness surface in a welding range having a diameter smaller than 200 μm. Rolling bearing device.   The rolling bearing device according to claim 1, wherein a diameter dimension of a welding range by the laser welding is 150 to 100 μm. A spacer portion sandwiched in the axial direction between one of the outer rings or the inner rings,
The other inner ring or the outer ring is laser welded to the first member or the second member in a state of being pressed in a direction relatively close to the inner ring or the outer ring adjacent in the axial direction. The rolling bearing device according to claim 1 or 2.   A base member, the swing arm, and the rolling bearing device according to claim 1, wherein one of the first member and the second member is fixed to the base member. A pivot device in which the swing arm is attached to the other outer ring or inner ring. A rolling bearing device for swingably supporting a swing arm of a hard disk,
Coaxially arranged inner and outer rings, and a plurality of rolling elements arranged circumferentially in an annular space between the inner ring and the outer ring, and arranged outside in an axial direction. Two rolling bearings with a diameter of 10 mm or less ,
A first member fitted to each of the inner rings of the two rolling bearings;
A second member having a fitting hole for fitting the outer rings of the two rolling bearings;
The first member or the second member is provided so that the swing arm can be mounted,
At least one of the fitting portion between the inner ring and the first member and the fitting portion between the outer ring and the second member is at least one of the inner ring and the first member or the outer ring and the first member. At least one of the members 2 has a low roughness surface made of stainless steel and has a surface roughness Ra of 0.2 or less, and is laser welded by a laser beam applied to the low roughness surface in a welding range having a diameter smaller than 200 μm. Rolling bearing device.   The rolling bearing device according to claim 5, wherein a diameter size of a welding range by the laser welding is 150 to 100 μm. A spacer portion sandwiched in the axial direction between one of the outer rings or the inner rings,
The other inner ring or the outer ring is laser welded to the first member or the second member in a state of being pressed in a direction relatively close to the inner ring or the outer ring adjacent in the axial direction. The rolling bearing device according to claim 5 or 6.   A base member, the swing arm, and the rolling bearing device according to any one of claims 5 to 7, wherein any one of the first member and the second member is fixed to the base member. A pivot device in which the swing arm is attached to the other second member or the first member.

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