JP6210623B2 - Bearing device, bearing device manufacturing method, and information recording / reproducing device - Google Patents

Description

  The present invention relates to a bearing device, a method for manufacturing the bearing device, and an information recording / reproducing apparatus.

  2. Description of the Related Art Conventionally, an information recording / reproducing apparatus such as a hard disk for recording and reproducing various kinds of information on a disk (corresponding to a “magnetic recording medium” in claims) is known. In general, an information recording / reproducing apparatus includes a head gimbal assembly having a slider for recording / reproducing signals on / from a disk, and an arm (corresponding to a “rotating member” in the claims) on which a head gimbal assembly is mounted on the tip side. It has. This arm is rotatable by a bearing device provided on the base end side. By rotating the arm, the slider can be moved to a predetermined position on the disk to record and reproduce signals.

  Generally, a bearing device includes a shaft and a pair of rolling bearings that are inserted into the shaft and arranged side by side in the axial direction of the shaft. The pair of rolling bearings includes an inner ring fixed to the shaft, an outer ring surrounding the inner ring, a reinforcing sleeve covering the outer ring, and a plurality of rolling elements disposed between the inner ring and the outer ring. I have. The arm is fitted onto the outer ring via a sleeve.

  By the way, in the manufacturing process of a rolling bearing, the operation | work which arranges a some rolling element equally between an inner ring | wheel and an outer ring | wheel is performed (for example, refer patent document 1). Generally, in order to evenly arrange a plurality of rolling elements between the inner ring and the outer ring, the central axes of the inner ring and the outer ring are relatively shifted in the radial direction, and the outer diameter of the rolling element is between the inner ring and the outer ring. A plurality of rolling elements are individually inserted between the inner ring and the outer ring while providing a large gap. Then, after arrange | positioning a some rolling element equally to the circumferential direction, the retainer which can be hold | maintained in the state which arranged the rolling element uniformly so that rolling was possible is mounted | worn.

JP 2008-202606 A

  However, in the conventional rolling bearing manufacturing process, a plurality of rolling elements are inserted between the inner ring and the outer ring while shifting the inner ring and the outer ring. I need it. Moreover, in order to arrange a some rolling element equally, for example, exclusive manufacturing apparatuses, such as an air injection apparatus as described in a prior art, are needed, and a huge installation expense is required. Therefore, the manufacturing cost of the rolling bearing may be high.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a bearing device that can be manufactured by a simple operation and can be reduced in cost, a method for manufacturing the bearing device, and an information recording / reproducing apparatus including the bearing device.

In order to solve the above-described problem, a bearing device of the present invention includes a shaft and a pair of rolling bearing portions arranged side by side in the axial direction of the shaft, and the pair of rolling bearing portions are respectively the shaft. An inner ring disposed coaxially with the central axis of the shaft, an outer ring surrounding the inner ring from the outer side in the radial direction of the shaft, and a plurality of rolling elements that are rotatably held between the inner ring and the outer ring. And the separation distance between the innermost part of the rolling element and the central axis in the radial direction is defined as a first separation distance, and the separation distance between the outermost part of the rolling element and the central axis in the radial direction is defined as a second separation distance. The distance between the pair of rolling bearing portions in the axial direction is defined as the inner side of the axial direction, and the direction away from between the pair of rolling bearing portions in the axial direction is defined as the outer side of the axial direction . When said The inner rings of the pair of rolling bearing portions each have an outer radius of the outer end portion in the axial direction smaller than the first separation distance, and the first separation from the outer side in the axial direction toward the inner side. An inner ring rolling surface formed to have an outer radius larger than the distance, and the outer ring of the pair of rolling bearing portions has an inner radius of the inner end portion in the axial direction that is greater than the second separation distance. And an outer ring rolling surface formed so that the inner radius becomes smaller than the second separation distance from the inner side to the outer side in the axial direction.

According to the present invention, each of the inner rings of the pair of rolling bearing portions is formed such that the outer radius of the outer end portion in the axial direction is smaller than the first separation distance, and the first is directed from the outer side to the inner side in the axial direction. Since the inner ring rolling surface is formed so that the outer radius is larger than the separation distance, the rolling elements can be easily inserted by inserting the rolling elements from the outer end in the axial direction in an annularly arranged state. Can be placed on the inner ring rolling surface. Further, the outer rings of the pair of rolling bearing portions are each formed such that the inner radius of the inner end portion in the axial direction is larger than the second separation distance, and the outer race is larger than the second separation distance from the inner side to the outer side in the axial direction. Since it has an outer ring rolling surface formed so that the inner radius is small, the rolling element can be easily rolled by inserting it from the inner end in the axial direction with the rolling elements evenly arranged in an annular shape. Can be placed on the surface. This eliminates the need for the conventional complicated work of inserting the rolling elements between the inner ring and the outer ring while shifting the inner ring and the outer ring, and arranging the plurality of rolling elements equally in the circumferential direction, and a dedicated manufacturing device. The rolling bearing part can be manufactured with a simple operation. Therefore, the cost of the bearing device can be reduced.
Also, when the rolling elements are inserted between the inner ring and the outer ring while shifting the inner ring and the outer ring as in the prior art, the number and size of the rolling elements that can be inserted depends on the size of the gap between the inner ring and the outer ring. It will be limited. On the other hand, according to the present invention, the outer ring is inserted from the axial direction after placing the rolling element on the inner ring rolling surface, or the inner ring from the axial direction after placing the rolling element on the outer ring rolling surface. By inserting, a plurality of rolling elements are arranged between the inner ring rolling surface and the outer ring rolling surface, so that the number and size are not limited by the gap between the inner ring and the outer ring as in the prior art. You can place moving objects. Therefore, the rigidity of the bearing device can be increased.

  Further, the outer end portion in the axial direction of the inner ring is arranged on the inner side in the axial direction with respect to the outer end portion in the axial direction of the outer ring.

  According to the present invention, since the axial length of the inner ring can be shortened, the bearing device can be reduced in size, weight, and cost.

  Further, the distance from the virtual surface including the centers of the plurality of rolling elements to the inner end portion in the axial direction of the outer ring is shorter than the distance from the virtual surface to the outer end portion in the axial direction of the outer ring. It is characterized by being formed as follows.

  According to the present invention, since the axial length of the outer ring can be shortened, the bearing device can be further reduced in size, weight, and cost. Further, since the length of the inner end portion in the axial direction of the outer ring that limits the thinning of the bearing device can be shortened, the bearing device can be further thinned.

  In addition, at least one of the inner rings of the pair of rolling bearing portions and the shaft are integrally formed with each other.

  According to the present invention, since the number of parts of the bearing device can be reduced, the bearing device can be further reduced in size, weight, and cost. In addition, since it is not necessary to insert at least one of the inner rings of the pair of rolling bearing portions into the shaft, the number of assembling steps of the bearing device can be shortened and the manufacturing cost can be reduced. Therefore, the cost of the bearing device can be further reduced.

  In addition, the inner rings of the pair of rolling bearing portions are formed integrally with each other.

  According to the present invention, since the number of parts of the bearing device can be reduced, the bearing device can be further reduced in size, weight, and cost. In particular, since the inner rings of the pair of rolling bearing portions are integrally formed, it is not necessary to secure a space between the inner rings of the pair of rolling bearing portions by, for example, providing a spacer. Can be

  Further, the inner ring and the outer ring are formed by forging.

  According to the present invention, the inner ring and the outer ring can be formed at low cost by forging, and the number of cutting processes can be shortened. Therefore, the cost of the bearing device can be further reduced.

  Further, the retainer is disposed between the inner ring and the outer ring, and includes a retainer that can hold the plurality of rolling elements so as to be able to roll and can be evenly arranged in an annular shape. The retainer includes a main body, and the main body from the main body. A plurality of pairs of claw portions that are erected along the axial direction and hold the rolling element in a freely rollable manner, and the main body portion is arranged in the axial direction with respect to the rolling element. Yes.

According to the present invention, since the plurality of pairs of claw portions are erected from the main body portion along the axial direction, the plurality of pairs of claw portions are inclined with respect to the axial direction. In comparison, the inner radius of the retainer can be increased as much as possible, and the outer radius of the retainer can be decreased as much as possible. Therefore, interference between the retainer, the inner ring, and the outer ring can be reliably suppressed, and the bearing device can be downsized in the radial direction.
Further, since the main body portion of the retainer can be disposed in the dead space on the inner side in the axial direction than the rolling elements, it is possible to prevent the thinning of the bearing device from being restricted by the main body portion of the retainer. As a result, the bearing device can be made as thin as possible.

Further, the pair of rolling bearing portions includes a cylindrical sleeve to which the outer ring is inserted and fixed .

  According to the present invention, since the outer diameter of the bearing device can be made uniform, a rotating member such as an arm can be mounted on the bearing device with high accuracy.

  Further, the outer rings of the pair of rolling bearing portions are fixed to the sleeve in a state where a preload is applied relative to each other.

  According to the present invention, it is possible to provide a so-called outer ring preload bearing device that is fixed to the sleeve in a state in which a preload is applied to the outer ring of the pair of rolling bearing portions.

  Further, the outer end portion in the axial direction of the sleeve is arranged on the inner side in the axial direction with respect to the outer end portion in the axial direction of the outer ring.

  According to the present invention, since the axial length of the sleeve can be shortened, the bearing device can be further reduced in size, weight, and cost.

  The bearing device manufacturing method of the present invention includes a first outer ring arrangement step of inserting a first outer ring of the outer rings of the pair of rolling bearing portions into the sleeve and fixing the sleeve to one side in the axial direction of the sleeve. Each of the first retainer and the second retainer capable of holding the rolling elements, the retainer holding step of holding the plurality of rolling elements so as to be able to roll and arranging them in an annular shape, and the first outer ring, Inserting the plurality of rolling elements together with the first retainer from the other side in the axial direction, and placing the plurality of rolling elements on the outer ring rolling surface of the first outer ring; A first inner ring arrangement step in which a first inner ring is arranged inside the first outer ring of the inner ring of the rolling bearing portion, and an inner ring rolling surface of the first inner ring is brought into contact with the plurality of rolling elements; Among the inner rings of the pair of rolling bearing portions, the second inner A second inner ring disposing step of disposing the plurality of rolling elements together with the second retainer from the other side in the axial direction into the second inner ring. A second rolling element arrangement step of placing the plurality of rolling elements on a rolling surface, and a second outer ring of the outer rings of the pair of rolling bearing portions is inserted into the sleeve and arranged on the other side in the axial direction. A second outer ring arranging step, and a preload adding step of fixing the second outer ring to the sleeve while relatively pressing the first outer ring and the second outer ring along the axial direction. It is characterized by.

According to the present invention, after the plurality of rolling elements are arranged in an annular shape in advance in the retainer holding step, a plurality of rolling elements are provided for each of the first retainer and the second retainer in the first rolling element arranging step and the second rolling element arranging step. Can be placed on the outer ring rolling surface of the first outer ring and the inner ring rolling surface of the second inner ring. This eliminates the conventional troublesome work of inserting the rolling elements between the inner ring and the outer ring while shifting the inner ring and the outer ring, and arranging the plurality of rolling elements evenly in the circumferential direction. Can be formed.
Furthermore, since the outer ring of the pair of rolling bearing portions includes an outer ring rolling surface formed so that the inner radius becomes smaller than the second separation distance from the inner side to the outer side in the axial direction, the first rolling element In the arrangement step, a plurality of rolling elements can be inserted into the first outer ring from the other axial side (the inner side in the axial direction) and can be easily placed on the outer ring rolling surface without using a jig or the like. Further, since the inner ring of the pair of rolling bearing portions includes an inner ring rolling surface formed so that the outer radius becomes larger than the first separation distance from the outside in the axial direction to the inside, the second rolling element In the arrangement step, a plurality of rolling elements can be inserted into the inner ring from the other side in the axial direction (outside in the axial direction), and can be easily placed on the inner ring rolling surface without using a jig or the like.
Also, when the rolling elements are inserted between the inner ring and the outer ring while shifting the inner ring and the outer ring as in the prior art, the number and size of the rolling elements that can be inserted depends on the size of the gap between the inner ring and the outer ring. It will be limited. On the other hand, according to the present invention, the first inner ring arrangement step of inserting the outer ring from the axial direction after placing the rolling element on the outer ring rolling surface, and the shaft after placing the rolling element on the inner ring rolling surface And the second outer ring arrangement step of inserting the outer ring from the direction, so that the rolling elements can be arranged without being limited in number or size by the gap between the inner ring and the outer ring as in the prior art. Therefore, the rigidity of the bearing device can be increased.
Thus, according to the method for manufacturing a bearing device of the present invention, the bearing device can be easily manufactured, so that the manufacturing cost can be reduced and the cost of the bearing device can be reduced.

  The information recording / reproducing apparatus according to the present invention includes the above-described bearing device, a housing that supports one end of the bearing device, and a rotation that is fitted around the outer ring and rotates around the central axis of the shaft. And a slider that is mounted on the rotating member and that records and reproduces information with a magnetic recording medium.

According to the present invention, since the bearing device that can be manufactured by a simple operation and can be reduced in cost is provided, the cost of the information recording / reproducing apparatus can be reduced.
Further, since the outer ring is fixed to the sleeve with the preload applied, the pair of rolling bearing portions can be made highly rigid. Thereby, since the resonance frequency (resonance point) of a bearing apparatus can be made high, a rotation member can be rotated at high speed. Therefore, the performance of the information recording / reproducing apparatus can be improved.

According to the present invention, each of the inner rings of the pair of rolling bearing portions is formed such that the outer radius of the outer end portion in the axial direction is smaller than the first separation distance, and the first is directed from the outer side to the inner side in the axial direction. Since the inner ring rolling surface is formed so that the outer radius is larger than the separation distance, the rolling elements can be easily inserted by inserting the rolling elements from the outer end in the axial direction in an annularly arranged state. Can be placed on the inner ring rolling surface. Further, the outer rings of the pair of rolling bearing portions are each formed such that the inner radius of the inner end portion in the axial direction is larger than the second separation distance, and the outer race is larger than the second separation distance from the inner side to the outer side in the axial direction. Since it has an outer ring rolling surface formed so that the inner radius is small, the rolling element can be easily rolled by inserting it from the inner end in the axial direction with the rolling elements evenly arranged in an annular shape. Can be placed on the surface. This eliminates the need for the conventional complicated work of inserting the rolling elements between the inner ring and the outer ring while shifting the inner ring and the outer ring, and arranging the plurality of rolling elements equally in the circumferential direction, and a dedicated manufacturing device. The rolling bearing part can be manufactured with a simple operation. Therefore, the cost of the bearing device can be reduced.
Also, when the rolling elements are inserted between the inner ring and the outer ring while shifting the inner ring and the outer ring as in the prior art, the number and size of the rolling elements that can be inserted depends on the size of the gap between the inner ring and the outer ring. It will be limited. On the other hand, according to the present invention, the outer ring is inserted from the axial direction after placing the rolling element on the inner ring rolling surface, or the inner ring from the axial direction after placing the rolling element on the outer ring rolling surface. By inserting, a plurality of rolling elements are arranged between the inner ring rolling surface and the outer ring rolling surface, so that the number and size are not limited by the gap between the inner ring and the outer ring as in the prior art. You can place moving objects. Therefore, the rigidity of the bearing device can be increased.

1 is a perspective view of an information recording / reproducing apparatus according to an embodiment. It is side surface sectional drawing of the bearing apparatus which concerns on 1st embodiment. It is a perspective view of a 1st retainer and a 2nd retainer. It is a flowchart of the manufacturing process of a bearing device. It is explanatory drawing of a 1st outer ring arrangement | positioning process. It is explanatory drawing of a retainer holding process. It is explanatory drawing of a 1st rolling element arrangement | positioning process. It is explanatory drawing of a 1st inner ring arrangement | positioning process. It is explanatory drawing of a 2nd inner ring arrangement | positioning process. It is explanatory drawing of a 2nd rolling element arrangement | positioning process. It is explanatory drawing of a 2nd outer ring arrangement | positioning process and a preload addition process. It is explanatory drawing of the bearing apparatus which concerns on the 1st modification of 1st embodiment. It is explanatory drawing of the bearing apparatus which concerns on the 2nd modification of 1st embodiment. It is explanatory drawing of the bearing apparatus which concerns on the 3rd modification of 1st embodiment. It is explanatory drawing of the bearing apparatus of 2nd embodiment. It is explanatory drawing of the bearing apparatus of 3rd embodiment. It is explanatory drawing of the bearing apparatus of 4th embodiment.

  The bearing device, the manufacturing method of the bearing device, and the information recording / reproducing device according to the first embodiment will be described below. In the following, after describing the information recording / reproducing apparatus according to the embodiment, the bearing device according to the first embodiment and the method of manufacturing the bearing device will be described.

(Information recording / reproducing device)
FIG. 1 is a perspective view of an information recording / reproducing apparatus 1 according to the embodiment.
As shown in FIG. 1, the information recording / reproducing apparatus 1 is an apparatus that writes and reads data on a disk (magnetic recording medium) D having a recording layer. The information recording / reproducing apparatus 1 includes an arm (rotating member) 8, a head gimbal assembly 4 supported on the tip side of the arm 8, a slider 2 attached to the tip of the head gimbal assembly 4, and a head gimbal assembly 4. An actuator (VCM: voice coil motor) 6 for moving the scan, a spindle motor 7 for rotating the disk D, a control unit 5 for supplying a current modulated in accordance with information to the slider 2, and these components are housed inside. And a housing 9 to be provided.

  The housing 9 is made of a metal material such as aluminum, iron, or stainless steel, and has a box shape with an opening at the top. The housing 9 stands vertically from the rectangular bottom 9a and the peripheral edge of the bottom 9a. It is comprised with the surrounding wall (not shown) provided. A housing recess for housing each of the above-described components is formed inside the housing 9 surrounded by the peripheral wall. A spindle motor 7 is attached to substantially the center of the bottom portion 9a, and the disc D is detachably fixed by fitting a center hole into the spindle motor 7.

A bearing device 10 is disposed on the side of the disk D. One end of the bearing device 10 is supported by the bottom 9 a of the housing 9. An arm 8 is fitted and fixed to the outer peripheral surface of the bearing device 10. The base end portion of the arm 8 is connected to the actuator 6 described above. Further, the arm 8 extends in parallel with the surface of the disk D from the proximal end side toward the distal end side.
A head gimbal assembly 4 is connected to the tip of the arm 8. The head gimbal assembly 4 includes a suspension 3 and a slider 2 that is attached to the tip of the suspension 3 and is disposed to face the surface of the disk D. The slider 2 includes a recording element for writing (recording) information on the disk D and a reproducing element for reading (reproducing) information from the disk D.

  In the information recording / reproducing apparatus 1 configured as described above, in order to record or reproduce information, the spindle motor 7 is first driven to rotate the disk D around the central axis L2 of the disk D. Further, the actuator 6 is driven to rotate the arm 8 around the bearing device 10 as the rotation center. As a result, the slider 2 disposed at the tip of the head gimbal assembly 4 can be scanned and moved to each part of the surface of the disk D. Then, by driving the recording element or reproducing element of the slider 2, information can be recorded or reproduced on the disk D.

(Bearing device of the first embodiment)
FIG. 2 is a side cross-sectional view of the bearing device 10 according to the first embodiment. In FIG. 2, the housing 9 and the bottom portion 9 a of the housing 9 are illustrated by a two-dot chain line. Hereinafter, a direction along the axis of the bearing device 10 (that is, the axis of the shaft 20; hereinafter referred to as “center axis L1”) is referred to as “axial direction”. Further, in the axial direction, the bottom 9a side (that is, the lower side in FIG. 2) of the housing 9 shown in FIG. 1 is referred to as “one side”, and the opening side (that is, the upper side in FIG. 2) is “the other side”. Call it. The inner side in the axial direction of the pair of rolling bearing portions 30 and 40 is referred to as “inner side in the axial direction”, and the outer side in the axial direction of the pair of rolling bearing portions 30 and 40 is referred to as “outer side in the axial direction”. Further, a direction orthogonal to the central axis L1 is referred to as a “radial direction”, and a direction around the central axis L1 is referred to as a “circumferential direction”.
As shown in FIG. 2, the bearing device 10 according to the first embodiment includes a shaft 20 erected on the bottom portion 9 a of the housing 9, and a pair of rolling bearing portions 30 arranged side by side in the axial direction of the shaft 20. 40.

The shaft 20 is a substantially cylindrical member extending along the central axis L1, and is formed of a metal material such as aluminum, iron, or stainless steel. The shaft 20 has a base end portion on the bottom 9a side of the housing 9 and a tip end portion on the opposite side along the axial direction.
At the base end portion of the shaft 20, a flange portion 20 a having a diameter larger than the diameter of the shaft 20 and a reduced diameter portion 20 b having a diameter smaller than the diameter of the shaft 20 are directed from the other side in the axial direction toward one side. They are arranged in this order. The reduced diameter portion 20 b is formed with a male screw (not shown) that is screwed into a female screw (not shown) formed on the bottom 9 a of the housing 9. The shaft 20 is erected on the bottom portion 9a of the housing 9 by the screwing. At this time, the flange portion 20 a is in contact with the bottom portion 9 a of the housing 9, whereby the shaft 20 is positioned in the height direction.

(Rolling bearing)
The shaft 20 is provided with a pair of rolling bearing portions 30 and 40 arranged side by side in the axial direction, and the first rolling bearing portion of the pair of rolling bearing portions 30 and 40 is disposed on one side in the axial direction of the shaft 20. 30 is disposed, and the second rolling bearing portion 40 is disposed on the other axial side of the shaft 20.

(First rolling bearing)
The first rolling bearing portion 30 includes a first inner ring 36 disposed coaxially with the central axis L1 of the shaft 20, a first outer ring 31 surrounding the first inner ring 36 from the outside in the radial direction of the shaft 20, and a first A plurality of rolling elements 35 that are rotatably held between the inner ring 36 and the first outer ring 31, and a first retainer 60 that evenly arranges the plurality of rolling elements 35 in an annular manner so as to be capable of rolling. .
Hereinafter, the separation distance between the innermost part of the plurality of rolling elements 35 in the radial direction and the central axis L1 is defined as a first separation distance K1, and the outermost part of the plurality of rolling elements 35 in the radial direction and the central axis A separation distance from L1 is defined as a second separation distance K2.

(First inner ring)
The first inner ring 36 is a substantially cylindrical member made of a metal material such as stainless steel, and is formed by forging or machining, for example.
The first inner ring 36 is formed such that the outer radius of the outer end 36a in the axial direction is smaller than the first separation distance K1.
An inner ring rolling surface 39 is formed at an axial intermediate portion of the outer peripheral surface 37 of the first inner ring 36. The inner ring rolling surface 39 has an arcuate side surface cross section so that the outer radius gradually becomes larger than the first separation distance K1 from the outside in the axial direction toward the inside. The inner ring rolling surface 39 is formed over the entire circumference of the outer circumferential surface 37 of the first inner ring 36, and the outer surfaces of the plurality of rolling elements 35 arranged in an annular shape can contact each other.

  The inner diameter of the first inner ring 36 is formed to a size that can be inserted into the shaft 20. In the present embodiment, the inner diameter of the first inner ring 36 is formed to be slightly larger than the outer diameter of the shaft 20. The first inner ring 36 is inserted into the shaft 20 and fixed to one side in the axial direction of the shaft 20 with, for example, an adhesive or the like in a state where the outer end portion 36 a is in contact with the flange portion 20 a of the shaft 20. The inner diameter of the first inner ring 36 may be formed to be the same as or slightly smaller than the outer diameter of the shaft 20. In this case, the first inner ring 36 is inserted into the shaft 20 and is press-fitted and fixed.

  The first inner ring 36 has an outer diameter that increases from the outer side toward the inner side in the axial direction, and the inner diameter is uniform. Therefore, when forming the outer shape of the first inner ring 36, forging is suitable. And after forming the outer shape of the 1st inner ring | wheel 36 by forging, the man-hour which performs a machining can be shortened significantly by cutting the inner ring rolling surface 39, Therefore A manufacturing cost can be reduced.

(First outer ring)
Like the first inner ring 36, the first outer ring 31 is a substantially cylindrical member made of a metal material such as stainless steel, and is formed by forging or machining, for example.
The first outer ring 31 is formed such that the inner radius of the inner end portion 31b in the axial direction is larger than the second separation distance K2.
An outer ring rolling surface 34 is formed at an axial intermediate portion of the inner peripheral surface 33 of the first outer ring 31. The outer ring rolling surface 34 has a side cross section formed in an arc shape so that the inner radius gradually becomes smaller than the second separation distance K2 from the inner side to the outer side in the axial direction. The outer ring rolling surface 34 is formed over the entire circumference of the inner circumferential surface 33 of the first outer ring 31, and the outer surfaces of a plurality of rolling elements 35 arranged in an annular shape can come into contact therewith. The outer peripheral surface of the first outer ring 31 is formed so that the outer diameter is uniform over the axial direction.
Forging the outer shape of the first outer ring 31 is suitable. And after forming the outer shape of the 1st outer ring | wheel 31 by forging, since the man-hour which performs a machining can be reduced significantly by cutting the outer ring rolling surface 34, manufacturing cost can be reduced.

  The rolling element 35 is formed in a spherical shape from a metal material. The rolling element 35 is disposed between the outer ring rolling surface 34 of the first outer ring 31 and the inner ring rolling surface 39 of the first inner ring 36, and rolls along the rolling surfaces 34, 39. ing. The radius of curvature of each of the rolling surfaces 34 and 39 is formed to be slightly larger than the radius of curvature of the outer surface of the rolling element 35. The plurality of rolling elements 35 are evenly arranged in an annular shape along the circumferential direction so as to roll freely by the first retainer 60.

(First retainer)
FIG. 3 is a perspective view of the first retainer 60 and the second retainer 70.
The first retainer 60 is a member made of, for example, a resin or the like that holds the rolling elements 35 in a rollable manner while rotating around the central axis L1 by the guidance of the first outer ring 31, the first inner ring 36, and the rolling elements 35. The main body 61 and a plurality of pairs of claw parts 63 formed integrally with the main body 61 are provided.
As shown in FIG. 3, the main body 61 is formed in an annular shape surrounding the first inner ring 36 from the outside in the radial direction. On the other side in the axial direction of the main body 61, for example, seven spherical ball pockets P into which the rolling elements 35 can be inserted at equal intervals in the circumferential direction are formed indented.

  The main body portion 61 is provided with a pair of claw portions 63 so as to correspond to the respective ball pockets P. The pair of claws 63 can hold the rolling element 35 inserted into the ball pocket P so as to roll freely. The claw portions 63 face each other in the circumferential direction with the ball pockets P interposed therebetween, and are curved in an arc shape so that the distance from each other approaches from the proximal end toward the distal end. Is erected along. As shown in FIG. 2, a plurality of (seven in this embodiment) rolling elements 35 are held by the ball pockets P of the first retainer 60 in a state of being arranged at substantially equal intervals in the circumferential direction. 36 and the first outer ring 31.

Here, as shown in FIG. 2, the inner radius of the first retainer 60 is larger than the maximum outer radius of the first inner ring 36, and the outer radius of the first retainer 60 is larger than the minimum inner radius of the first outer ring 31. Is formed to be smaller. By forming the first retainer 60 in this way, the first retainer 60 and the first inner ring 36 and the first outer ring 31 do not interfere with each other, and the plurality of rolling elements 35 are moved to the inner ring rolling surface 39 of the first inner ring 36. And the outer ring rolling surface 34 of the first outer ring 31.
Further, since the plurality of pairs of claw portions 63 are respectively erected along the axial direction from the main body portion 61, compared to the case where the plurality of pairs of claw portions 63 are inclined with respect to the axial direction. The inner radius of the first retainer 60 can be increased as much as possible, and the outer radius of the first retainer 60 can be decreased as much as possible. Therefore, the first retainer 60, the first inner ring 36, and the first outer ring 31 can be reliably prevented from interfering with each other, and the bearing device 10 can be downsized in the radial direction.

(Second rolling bearing)
The second rolling bearing portion 40 includes a second inner ring 46 fixed to the shaft 20 coaxially with the central axis L1 of the shaft 20, and a second outer ring 41 surrounding the second inner ring 46 from the outside in the radial direction of the shaft 20. A plurality of rolling elements 35 that are rotatably held between the second inner ring 46 and the second outer ring 41, and a second retainer 70 that annularly arranges the plurality of rolling elements 35 in a ring-like manner. I have. In the present embodiment, the second inner ring 46 and the second outer ring 41 of the second rolling bearing portion 40 are formed in plane symmetry with the first inner ring 36 and the first outer ring 31 of the first rolling bearing portion 30, respectively. The second retainer 70 is the same member as the first retainer 60 (see FIG. 3). Therefore, detailed description of the second rolling bearing portion 40 is omitted.

(Spacer)
A spacer 55 is disposed between the first inner ring 36 of the first rolling bearing portion 30 and the second inner ring 46 of the second rolling bearing portion 40. The spacer 55 is a member made of a metal material such as aluminum, iron, or stainless steel, and is formed by forging, machining, or the like.
The outer diameter of the spacer 55 is substantially the same as the outer diameter of the inner end portion 36 b of the first inner ring 36 of the first rolling bearing portion 30 and the outer diameter of the inner end portion 46 b of the second inner ring 46 of the second rolling bearing portion 40. It is formed to become. The inner diameter of the spacer 55 is formed to be substantially the same as the inner diameter of the first inner ring 36 and the inner diameter of the second inner ring 46 so that the spacer 55 can be inserted into the shaft 20 together with the first inner ring 36 and the second inner ring 46. Yes.
By interposing the spacer 55 between the first inner ring 36 and the second inner ring 46, the first rolling bearing part 30 and the second rolling bearing part 40 can be arranged in a state of being separated by a predetermined interval in the axial direction. Further, in a preload application step S25 (see FIG. 11) described later, when the first outer ring 31 and the second outer ring 41 are relatively pressed along the axial direction, the separation distance between the first inner ring 36 and the second inner ring 46 is increased. Can be applied to the first outer ring 31 and the second outer ring 41 by shortening the separation distance between the first outer ring 31 and the second outer ring 41.

(sleeve)
Similarly to the spacer 55, the sleeve 50 is formed in a substantially cylindrical shape from a metal material such as aluminum, iron, or stainless steel, and is formed by forging, machining, or the like.
The inner diameter of the sleeve 50 is formed to be larger than the outer diameters of the first rolling bearing portion 30 and the second rolling bearing portion 40 so as to be extrapolated to the first rolling bearing portion 30 and the second rolling bearing portion 40. Has been. The sleeve 50 is fixed to the first outer ring 31 of the first rolling bearing portion 30 and the second outer ring 41 of the second rolling bearing portion 40 by, for example, an adhesive.
By providing the sleeve 50, the outer diameter of the bearing device 10 can be made uniform. Therefore, since the arm 8 (see FIG. 1) can be mounted with high precision on the bearing device 10, a high-performance information recording / reproducing apparatus 1 (see FIG. 1) can be formed.

In the first rolling bearing portion 30 and the second rolling bearing portion 40 formed as described above, a spacer 55 is interposed between the inner end portion 36 b of the first inner ring 36 and the inner end portion 46 b of the second inner ring 46. In such a state, they are arranged side by side along the axial direction of the shaft 20 so as not to interfere with each other. Further, the first outer ring 31 of the first rolling bearing portion 30 and the second outer ring 41 of the second rolling bearing portion 40 are fixed to the sleeve 50 with a preload applied thereto.
At this time, the outer end 36a of the first inner ring 36 and the outer end 31a of the first outer ring 31 of the first rolling bearing portion 30 and the one outer end 50a of the sleeve 50 are at substantially the same position in the axial direction. Has been placed. Further, the outer end 46a of the second inner ring 46 and the outer end 41a of the second outer ring 41 of the second rolling bearing portion 40 and the other outer end 50b of the sleeve 50 are arranged at substantially the same position in the axial direction. Has been. That is, the bearing device 10 is formed such that the outer end surfaces of the first rolling bearing portion 30 and the second rolling bearing portion 40 and both outer end surfaces of the sleeve 50 are substantially flush with each other.

(Bearing device manufacturing method)
Then, the manufacturing method of the bearing apparatus 10 of this embodiment is demonstrated.
FIG. 4 is a flowchart of the manufacturing process (manufacturing method) of the bearing device 10.
As shown in FIG. 4, the manufacturing process of the bearing device 10 includes a first outer ring arrangement process S11, a retainer holding process S13, a first rolling element arrangement process S15, a first inner ring arrangement process S17, and a second inner ring arrangement. A step S19, a second rolling element arrangement step S21, a second outer ring arrangement step S23, and a preload application step S25 are provided. Below, each process is demonstrated.

(First outer ring arrangement step S11)
FIG. 5 is an explanatory diagram of the first outer ring arrangement step S11.
First, as shown in FIG. 5, of the first outer ring 31 and the second outer ring 41 of the pair of rolling bearing portions 30 and 40 (see FIG. 2), the first outer ring 31 of the first rolling bearing portion 30 is a sleeve 50. A first outer ring arrangement step of inserting and fixing to one side of the sleeve 50 in the axial direction is performed.
In the first outer ring arrangement step S11, the sleeve 50 is placed on a jig (not shown), an adhesive is applied in advance to the inner peripheral surface of one side in the axial direction of the sleeve 50, and then from the other side in the axial direction. The first outer ring 31 is inserted into the sleeve 50 along the axial direction. Thereafter, the adhesive is solidified and the first outer ring 31 is fixed to the sleeve 50. Above, 1st outer ring arrangement | positioning process S11 is complete | finished.

(Retainer holding step S13)
FIG. 6 is an explanatory diagram of the retainer holding step S13.
Subsequently, as shown in FIG. 6, a retainer holding step S <b> 13 is performed in which each of the first retainer 60 and the second retainer 70 holds the plurality of rolling elements 35 so as to be able to roll and is arranged in an annular manner.
In the retainer holding step S <b> 13, the rolling element 35 is pushed between the pair of claws 63 of the first retainer 60, and the rolling element 35 is incorporated into the ball pocket P of the main body 61 of the first retainer 60. The pair of claws 63 are elastically deformed outward by a pressing force when the rolling element 35 is pushed in. Thereby, the rolling element 35 can be inserted between the pair of claws 63 and can be incorporated into the ball pocket P. Further, when the rolling element 35 is inserted into the ball pocket P, the pair of claws 63 are elastically restored to the original state and the opening diameter is narrowed, so that the rolling element 35 is dropped in the ball pocket P. It can hold | maintain freely by a pair of nail | claw part 63, without it. Similarly, by incorporating a plurality (seven in this embodiment) of rolling elements 35 into the first retainer 60, the plurality of rolling elements 35 can roll in a state of being evenly arranged in the circumferential direction by the first retainer 60. Retained. Similarly, when a plurality of (seven in the present embodiment) rolling elements 35 are incorporated into the second retainer 70, the retainer holding step S13 ends.
In addition, you may perform retainer holding process S13 before 1st outer ring arrangement | positioning process S11. In the present embodiment, the rolling element 35 is incorporated into the first retainer 60 and the second retainer 70 in one step (retainer holding step S13), but may be performed in a separate step. Specifically, it is divided into a first retainer holding step for incorporating the rolling elements 35 into the first retainer 60 and a second retainer holding step for incorporating the rolling elements 35 into the second retainer 70, and each retainer holding step is performed at different timings. You may go.

(First rolling element arrangement step S15)
FIG. 7 is an explanatory diagram of the first rolling element arrangement step S15.
Subsequently, as shown in FIG. 7, a plurality of rolling elements 35 are inserted into the first outer ring 31 from the other side in the axial direction together with the first retainer 60, and a plurality of rolling elements are placed on the outer ring rolling surface 34 of the first outer ring 31. A first rolling element arrangement step S15 for placing the moving element 35 is performed.
The inner radius of the inner end portion 31b of the first outer ring 31 is formed larger than the second separation distance K2. Therefore, in the first rolling element arrangement step S15, the plurality of rolling elements 35 can be easily inserted from the other side in the axial direction together with the first retainer 60 without interfering with the inner end 31b of the first outer ring 31. Further, the outer ring rolling surface 34 of the first outer ring 31 is formed so that the inner radius gradually becomes smaller than the second separation distance K2 from the inner side in the axial direction to the outer side (that is, from the other side in the axial direction to the one side). Has been. Therefore, in the first rolling element arrangement step S15, the plurality of rolling elements 35 are easily inserted into the first outer ring 31 together with the first retainer 60 from the other side in the axial direction, so that the plurality of rolling elements 35 can be easily put into the outer ring rolling surface. 34. In addition, since the plurality of rolling elements 35 are equally arranged and held by the first retainer 60 so as not to move relative to each other, the plurality of rolling elements 35 are placed on the outer ring rolling surface 34 without using a jig or the like. It can be held in the state. Thus, according to 1st rolling element arrangement | positioning process S15 of this embodiment, the some rolling element 35 can be easily arrange | positioned inside the radial direction of the 1st outer ring | wheel 31. FIG. Above, 1st rolling element arrangement | positioning process S15 is complete | finished.

(First inner ring arrangement step S17)
FIG. 8 is an explanatory diagram of the first inner ring arrangement step S17.
Subsequently, as shown in FIG. 8, among the first inner ring 36 and the second inner ring 46 (see FIG. 2) of the pair of rolling bearing portions 30 and 40, the first inner ring 36 is disposed inside the first outer ring 31. Then, the first inner ring arrangement step S <b> 17 is performed in which the inner ring rolling surface 39 of the first inner ring 36 is brought into contact with the plurality of rolling elements 35.
In the first inner ring arrangement step S17, for example, an insertion jig (not shown) corresponding to the shape of the shaft 20 (see FIG. 2) is erected along the central axis L1, and the outer end 36a of the first inner ring 36 is placed on one side. In this state, the first inner ring 36 is inserted along the axial direction from the other side of the insertion jig and arranged inside the first outer ring 31. The first inner ring 36 may be fixed in advance on one side of the shaft 20, and the first inner ring 36 together with the shaft 20 may be disposed inside the first outer ring 31.

  At this time, the outer radius of the outer end portion 36a of the first inner ring 36 is formed smaller than the first separation distance K1. Therefore, in the first inner ring arrangement step S17, the outer end 36a of the first inner ring 36 can be easily inserted from the other side in the axial direction without interfering with the plurality of rolling elements 35. Further, the inner ring rolling surface 39 of the first inner ring 36 is formed such that the outer radius gradually becomes larger than the first separation distance K1 from the outer side in the axial direction to the inner side (that is, from one side to the other side in the axial direction). Has been. Therefore, in the first inner ring arrangement step S <b> 17, when the first inner ring 36 is arranged on the inner side of the first outer ring 31 from the other side in the axial direction, the inner ring rolling surface 39 of the first inner ring 36 becomes a plurality of rolling elements 35. Can contact. As a result, the first inner ring 36 is positioned at a predetermined position in the axial direction. Therefore, without using a jig or the like, the first inner ring 36 is brought into contact with the plurality of rolling elements 35 with the inner ring rolling surface 39 in contact therewith. Can hold. Thus, according to the first inner ring arrangement step S17 of the present embodiment, the first inner ring 36 can be easily arranged inside the first outer ring 31 and on one side in the axial direction. Above, 1st inner ring arrangement | positioning process S17 is complete | finished. At this time, the first rolling bearing portion 30 is formed.

(Second inner ring arrangement step S19)
FIG. 9 is an explanatory diagram of the second inner ring arrangement step S19.
Subsequently, as shown in FIG. 9, among the first inner ring 36 and the second inner ring 46 (see FIG. 2) of the pair of rolling bearing portions 30 and 40, the second inner ring 46 is disposed on the other side in the axial direction. A two inner ring arrangement step S19 is performed.
In the second inner ring arrangement step S19, first, similarly to the first inner ring arrangement step S17, the spacer 55 is inserted along the axial direction from the other side of the insertion jig, and fixed to the other side of the first inner ring 36 with an adhesive or the like. To do. Thereafter, with the inner end 46b of the second inner ring 46 disposed on one side, the second inner ring 46 is inserted along the axial direction from the other side of the insertion jig and disposed on the other side in the axial direction. Above, 2nd inner ring arrangement | positioning process S19 is complete | finished.

(Second rolling element arrangement step S21)
FIG. 10 is an explanatory diagram of the second rolling element arrangement step S21. Subsequently, as shown in FIG. 10, a plurality of rolling elements 35 are inserted into the second inner ring 46 from the other side in the axial direction together with the second retainer 70, and a plurality of rolling elements are placed on the inner ring rolling surface 49 of the second inner ring 46. 2nd rolling element arrangement | positioning process S21 which mounts the moving body 35 is performed.
The outer radius of the outer end 46a of the second inner ring 46 is smaller than the first separation distance K1. Therefore, in the second rolling element arrangement step S21, the plurality of rolling elements 35 can be easily inserted together with the second retainer 70 from the other side in the axial direction without interfering with the outer end 46a of the second inner ring 46. Further, the inner ring rolling surface 49 of the second rolling bearing portion 40 (see FIG. 1) has an outer radius that is larger than the first separation distance K1 from the outer side in the axial direction toward the inner side (that is, from the other side in the axial direction). Is formed to gradually increase. Therefore, in the second rolling element arrangement step S21, the plurality of rolling elements 35 are simply inserted into the second inner ring 46 together with the second retainer 70 from the other side in the axial direction, so that the plurality of rolling elements 35 can be easily connected to the inner ring rolling surface. 49. In addition, since the plurality of rolling elements 35 are equally arranged and held by the second retainer 70 so as not to move relative to each other, the plurality of rolling elements 35 are placed on the inner ring rolling surface 49 without using a jig or the like. It can be held in the state. Thus, according to 2nd rolling element arrangement | positioning process S21 of this embodiment, the some rolling element 35 can be arrange | positioned to the radial direction outer side of the 2nd inner ring | wheel 46 easily. Above, 2nd rolling element arrangement | positioning process S21 is complete | finished.

(Second outer ring arrangement step S23)
FIG. 11 is an explanatory diagram of the second outer ring arranging step S23 and the preload adding step S25. Then, as shown in FIG. 11, among the first outer ring 31 and the second outer ring 41 of the pair of rolling bearing portions 30, 40, the second outer ring 41 of the second rolling bearing portion 40 is inserted into the sleeve 50, and the shaft 2nd outer ring arrangement | positioning process S23 arrange | positioned on the other side of a direction is performed.
In the second outer ring arranging step S23, the second outer ring 41 is inserted along the axial direction from the other side of the sleeve 50 with the inner end 41b of the second outer ring 41 arranged on one side. At this time, the inner radius of the inner end portion 41b of the second outer ring 41 arranged on one side in the axial direction is formed to be larger than the second separation distance K2. Accordingly, in the second outer ring arrangement step S23, the inner end 41b of the second outer ring 41 can be easily inserted from the other side in the axial direction without interfering with the plurality of rolling elements 35. Further, the outer ring rolling surface 44 of the second outer ring 41 is formed so that the inner radius gradually becomes smaller than the second separation distance K2 from the inner side in the axial direction to the outer side (that is, from one side to the other side in the axial direction). Has been. Therefore, in the second outer ring arrangement step S23, the outer ring rolling surface 44 of the second outer ring 41 can come into contact with the plurality of rolling elements 35 when the second outer ring 41 is inserted into the sleeve 50 from the other axial side. Thereby, since the second outer ring 41 is positioned at a predetermined position in the axial direction, the second outer ring 41 is moved in a state where the outer ring rolling surface 44 is in contact with the plurality of rolling elements 35 without using a jig or the like. Can hold. Thus, according to the second outer ring arrangement step S23 of the present embodiment, the second outer ring 41 can be easily arranged on the radially inner side of the sleeve 50 and on the other side in the axial direction. Above, 2nd outer ring arrangement | positioning process S23 is complete | finished.

(Preload application step S25)
Subsequently, as shown in FIG. 11, a preload adding step S25 for fixing the second outer ring 41 to the sleeve 50 while relatively pressing the first outer ring 31 and the second outer ring 41 along the axial direction is performed. In the present embodiment, the first outer ring 31 and the second outer ring are pressed by pressing the second outer ring 41 from the other side toward one side (that is, the first outer ring 31 side) with the first outer ring 31 fixed. 41 is relatively pressed. The second inner ring 46 is pressed using a jig (not shown).
By pressing the second outer ring 41 of the second rolling bearing part 40, the distance between the first outer ring 31 of the first rolling bearing part 30 and the second outer ring 41 of the second rolling bearing part 40 is shortened. Here, the separation distance between the first inner ring 36 of the first rolling bearing portion 30 and the second inner ring 46 of the second rolling bearing portion 40 is held at a predetermined distance by the spacer 55. Therefore, by pressing the second outer ring 41 toward one side, the rolling element 35 of the second rolling bearing portion 40 presses the inner ring rolling surface 49 of the second inner ring 46 and the first through the spacer 55. The inner ring 36 is pressed toward one side. In addition, when the first inner ring 36 is pressed toward one side, the rolling element 35 of the first rolling bearing portion 30 is pressed against the inner ring rolling surface 39 of the first inner ring 36, and the outer side of the first outer ring 31. The ring rolling surface 34 is pressed.
In this way, by pressing the second outer ring 41 of the second rolling bearing portion 40 along the axial direction from the other side to the one side, the first outer ring 31 and the second rolling of the first rolling bearing portion 30 are pressed. A preload is applied to the second outer ring 41 of the bearing portion 40. Then, the second outer ring 41 of the second rolling bearing portion 40 is pressed until the adhesive is cured.
When the adhesive is cured, the preloading step S25 is finished.
And the bearing apparatus 10 which concerns on this embodiment is completed when the 1st rolling bearing part 30 and the 2nd rolling bearing part 40 are inserted in the shaft 20 (refer FIG. 2), and are fixed with the adhesive agent etc., for example.

  In the first outer ring arrangement step S11 and the preload application step S25 of the present embodiment, the first outer ring 31 and the second outer ring 41 are fixed to the sleeve 50 by using an adhesive, respectively. On the other hand, for example, the first outer ring 31 and the second outer ring 41 may be fixed to the sleeve 50 by press-fitting, laser welding, or the like. In the embodiment, after the preloading step S25, the first rolling bearing portion 30 and the second rolling bearing portion 40 are inserted into the shaft 20 and fixed with an adhesive or the like. On the other hand, you may fix the 1st rolling bearing part 30 and the 2nd rolling bearing part 40 to the shaft 20 by press injection, laser welding, etc., for example. Accordingly, the first outer ring 31 and the second outer ring 41 can be fixed to the sleeve 50 without using an adhesive, and the first rolling bearing part 30 and the second rolling bearing part 40 can be fixed to the shaft 20. Therefore, generation | occurrence | production of the outgas from an adhesive agent can be prevented and the defect of the information recording / reproducing apparatus 1 resulting from an outgas can be prevented.

(Effects of the first embodiment)
According to the first embodiment, the second inner ring 46 of the second rolling bearing portion 40 is formed such that the outer radius of the outer end portion 46a in the axial direction is smaller than the first separation distance K1, and the outer side in the axial direction. Since the inner ring rolling surface 49 is formed so that the outer radius gradually becomes larger than the first separation distance K1 from the inner side toward the inner side, the outer end portion in the axial direction in a state where the rolling elements are evenly arranged in an annular shape By inserting from 46a, the rolling element 35 can be easily mounted on the inner ring rolling surface 49. The first outer ring 31 of the first rolling bearing portion 30 is formed such that the inner radius of the inner end portion 31b in the axial direction is larger than the second separation distance K2, and the first outer ring 31 extends from the inner side to the outer side in the axial direction. Since the outer ring rolling surface 34 is formed so that the inner radius is gradually smaller than the two separation distance K2, the rolling elements 35 are inserted from the inner end 31b in the axial direction in an annularly arranged state. Thus, the rolling element 35 can be easily placed on the outer ring rolling surface 34. This eliminates the need for the conventional complicated work of inserting the rolling elements between the inner ring and the outer ring while shifting the inner ring and the outer ring, and arranging the plurality of rolling elements equally in the circumferential direction, and a dedicated manufacturing device. The pair of rolling bearing portions 30 and 40 can be manufactured by a simple operation. Therefore, the cost of the bearing device 10 can be reduced.
Further, after the rolling element 35 is placed on the outer ring rolling surface 34 of the first outer ring 31, the first inner ring 36 is inserted from the axial direction, or the rolling element 35 is placed on the inner ring rolling surface 49 of the second inner ring 46. Since the plurality of rolling elements 35 are disposed between the inner ring rolling surfaces 39 and 49 and the outer ring rolling surfaces 34 and 44 by inserting the second outer ring 41 from the axial direction after the placement, as in the prior art. The rolling elements 35 can be arranged without being limited in number or size by the gap between the inner ring and the outer ring. Therefore, the rigidity of the bearing device 10 can be increased.

  According to the first embodiment, the first inner ring 36, the second inner ring 46, the first outer ring 31 and the second outer ring 41 can be formed at low cost by forging, and the number of cutting processes can be reduced. Therefore, the cost of the bearing device 10 can be further reduced.

Further, according to the first embodiment, after the plurality of rolling elements 35 are equally arranged in advance in the retainer holding step S13, the first retainer 60 is obtained in the first rolling element arranging step S15 and the second rolling element arranging step S21. A plurality of rolling elements 35 together with the second retainer 70 can be placed on the outer ring rolling surface 34 of the first outer ring 31 and the inner ring rolling surface 49 of the second inner ring 46. As a result, a pair of rolling bearings can be easily obtained without inserting the rolling elements between the inner ring and the outer ring while shifting the inner ring and the outer ring and arranging the plurality of rolling elements equally in the circumferential direction. Portions 30 and 40 can be formed.
Furthermore, the first outer ring 31 of the first rolling bearing portion 30 includes an outer ring rolling surface 34 formed so that the inner radius gradually becomes smaller than the second separation distance K2 from the inner side to the outer side in the axial direction. Therefore, when the plurality of rolling elements 35 are inserted into the first outer ring 31 from the other axial side (the inner side in the axial direction) in the first rolling element arrangement step S15, the outer ring rolling can be easily performed without using a jig or the like. It can be placed on the moving surface 34. The second inner ring 46 of the second rolling bearing portion 40 includes an inner ring rolling surface 49 formed so that the outer radius is gradually larger than the first separation distance K1 from the outside in the axial direction toward the inside. Therefore, in the second rolling element arrangement step S21, a plurality of rolling elements 35 are inserted into the second inner ring 46 from the other side in the axial direction (outside in the axial direction), and the inner ring rolling surface can be easily obtained without using a jig or the like. 49.
Thus, according to the method for manufacturing the bearing device 10 of the present invention, the bearing device 10 can be easily manufactured, so that the manufacturing cost can be reduced and the cost of the bearing device 10 can be reduced.

Further, according to the present embodiment, the information recording / reproducing apparatus 1 includes the bearing device 10 that can be manufactured by a simple operation and can be reduced in cost, so that the cost of the information recording / reproducing apparatus 1 can be reduced.
In addition, since the second outer ring 41 is fixed to the sleeve 50 with the preload applied, the rigidity of the pair of rolling bearing portions 30 and 40 can be increased. Thereby, since the resonance frequency (resonance point) of the bearing apparatus 10 can be made high, the arm 8 can be rotated at high speed. Therefore, the performance of the information recording / reproducing apparatus 1 can be improved.

(First modification of the first embodiment)
FIG. 12 is an explanatory diagram of a bearing device 10 according to a first modification of the first embodiment.
Then, the bearing apparatus 10 which concerns on each modification of 1st embodiment is demonstrated. In addition, below, description is abbreviate | omitted about the component similar to 1st embodiment, and only a different part is demonstrated.
In the bearing device 10 of the first embodiment, the outer end 36a of the first inner ring 36 and the outer end 31a of the first outer ring 31 of the first rolling bearing 30 and the one outer end 50a of the sleeve 50 are shafts. It was arrange | positioned in the substantially the same position in the direction (refer FIG. 2). In addition, the outer end 46a of the second inner ring 46 and the outer end 41a of the second outer ring 41 of the second rolling bearing portion 40 and the other outer end 50b of the sleeve 50 are arranged at substantially the same position in the axial direction. (See FIG. 2).
On the other hand, as shown in FIG. 12, in the bearing device 10 of the first modification of the first embodiment, the outer end 36 a of the first inner ring 36 and the outer end 46 a of the second inner ring 46 are respectively the first. Arranged on the inner side in the axial direction from the outer end 31a of the outer ring 31 and the outer end 41a of the second outer ring 41 and outside the contact part between the inner ring rolling surfaces 39, 49 and the rolling element 35. Has been.
According to the first modification of the first embodiment, the axial lengths of the first inner ring 36 and the second inner ring 46 can be shortened, so that the bearing device 10 can be reduced in size, weight, and cost.

(Second modification of the first embodiment)
FIG. 13 is an explanatory diagram of a bearing device 10 according to a second modification of the first embodiment.
Then, the bearing apparatus 10 which concerns on the 2nd modification of 1st embodiment is demonstrated. In addition, below, description is abbreviate | omitted about the component similar to 1st embodiment, and only a different part is demonstrated. Hereinafter, a virtual surface including the centers P1 of the plurality of rolling elements 35 of the first rolling bearing portion 30 is defined as a virtual plane F1, and a virtual including the centers P2 of the plurality of rolling elements 35 of the second rolling bearing portion 40 is defined. The surface is defined as a virtual surface F2 and will be described.
As shown in FIG. 13, in the bearing device 10 of the second modification of the first embodiment, the inner end 31 b of the first outer ring 31 and the inner end 41 b of the second outer ring 41 are outside of the first embodiment. May be arranged.

In the bearing device 10 according to the second modification of the first embodiment, for example, the distance D1 from the virtual surface F1 to the inner end portion 31b in the axial direction of the first outer ring 31 is the axial direction of the first outer ring 31 from the virtual surface F1. It arrange | positions so that it may become shorter than the distance D2 to the outer side edge part 31a. Similarly, the distance D3 from the virtual surface F2 to the inner end portion 41b in the axial direction of the second outer ring 41 is shorter than the distance D4 from the virtual surface F2 to the outer end portion 41a in the axial direction of the second outer ring 41. Is arranged.
According to the second modification of the first embodiment, since the axial lengths of the first outer ring 31 and the second outer ring 41 can be shortened, the bearing device 10 can be further reduced in size, weight, and cost. . Further, since the first outer ring 31 and the second outer ring 41 are reduced in weight, the resonance frequency (resonance point) of the bearing device 10 can be increased, so that the bearing device 10 that can swing and rotate at high speed can be provided. Further, since the lengths of the inner end 31b in the axial direction of the first outer ring 31 and the inner end 41b in the axial direction of the second outer ring 41 that limit the thinning of the bearing device 10 can be shortened, the bearing device 10 can be made thinner. Can be

(Third modification of the first embodiment)
FIG. 14 is an explanatory diagram of a bearing device 10 according to a third modification of the first embodiment.
Then, the bearing apparatus 10 which concerns on the 3rd modification of 1st embodiment is demonstrated. In addition, below, description is abbreviate | omitted about the component similar to 1st embodiment, and only a different part is demonstrated.
As shown in FIG. 14, in the bearing device 10 according to the third modification of the first embodiment, both outer end portions 50 a and 50 b of the sleeve 50 are respectively arranged on the inner side than the first embodiment. Both outer end portions 50a and 50b of the sleeve 50 are disposed on the outer side in the axial direction from the inner end portion 31b of the first outer ring 31 and the inner end portion 41b of the second outer ring 41, respectively. A part of the outer ring 31 and the second outer ring 41 may be covered from the radially outer side. Thereby, the sleeve 50 and the first outer ring 31 and the second outer ring 41 can be bonded and fixed.
According to the third modification of the first embodiment, since the axial length of the sleeve 50 can be shortened, the bearing device 10 can be further reduced in size, weight, and cost. Further, since the resonance frequency (resonance point) of the bearing device 10 can be increased by reducing the weight of the sleeve 50, the bearing device 10 that can swing and rotate at high speed can be provided.

(Second embodiment)
FIG. 15 is an explanatory diagram of the bearing device 210 of the second embodiment.
Then, the bearing apparatus 210 of 2nd embodiment is demonstrated. In addition, below, description is abbreviate | omitted about the component similar to 1st embodiment, and only a different part is demonstrated.
In the bearing device 10 of the first embodiment, the shaft 20, the first inner ring 36, and the second inner ring 46 are formed as separate parts (see FIG. 2).
On the other hand, as shown in FIG. 15, the bearing device 210 of the second embodiment includes a shaft 220, a first inner ring 36, a second inner ring 46 and a spacer 55 (first inner ring 36, second inner ring 46 and spacer 55 is integrally formed with a two-dot chain line). In this case, in the manufacturing process of the bearing device 210, the first inner ring arrangement step S17 and the second inner ring arrangement step S19 are performed simultaneously.

(Effect of the second embodiment)
According to the second embodiment, since the number of parts of the bearing device 210 can be reduced, the bearing device 210 can be further reduced in size, weight, and cost. In the first embodiment, in the manufacturing process of the bearing device 10, the first inner ring 36, the second inner ring 46, and the spacer 55 are inserted into an insertion jig (not shown), and are aligned in the axial direction on the same central axis L 1. (See FIGS. 8 and 9). On the other hand, in the second embodiment, since the shaft 220, the first inner ring 36, the second inner ring 46, and the spacer 55 are integrally formed, the first inner ring arrangement step S17 and the second inner ring arrangement step S19. Can be performed simultaneously. Therefore, the number of assembling steps in the manufacturing process of the bearing device 210 can be shortened, and the manufacturing cost can be reduced. Furthermore, no insertion jig is required in the manufacturing process of the bearing device 210. Therefore, the cost of the bearing device 210 can be further reduced. Further, the integral structure of the shaft 220, the first inner ring 36, the second inner ring 46, and the spacer 55 can increase the rigidity of the bearing device 210, that is, the resonance frequency (resonance point). Can be provided.

(Third embodiment)
FIG. 16 is an explanatory diagram of the bearing device 310 of the third embodiment.
Then, the bearing apparatus 310 of 3rd embodiment is demonstrated. In addition, below, description is abbreviate | omitted about the component similar to 1st embodiment, and only a different part is demonstrated.
In the bearing device 10 of the first embodiment, the first inner ring 36 and the second inner ring 46 are formed as separate parts (see FIG. 2).
On the other hand, as shown in FIG. 16, in the bearing device 310 of the third embodiment, the first inner ring 36 and the second inner ring 46 are integrally formed, and the first rolling bearing portion 30 and the second rolling ring 30. A common inner ring 336 of the bearing portion 40 is formed. In this case, in the manufacturing process of the bearing device 310, the first inner ring arrangement step S17 and the second inner ring arrangement step S19 are performed simultaneously.

(Effect of the third embodiment)
According to the third embodiment, since the number of parts of the bearing device 310 can be reduced, the bearing device 310 can be further reduced in size, weight, and cost. In particular, by forming the first inner ring 36 and the second inner ring 46 of the pair of rolling bearing portions 30 and 40 integrally, a space is provided between the first inner ring 36 and the second inner ring 46, for example. Therefore, the bearing device 310 can be further reduced in thickness.

(Fourth embodiment)
FIG. 17 is an explanatory diagram of the bearing device 410 according to the fourth embodiment.
Next, the bearing device 410 according to the fourth embodiment will be described. In addition, below, description is abbreviate | omitted about the component similar to 1st embodiment, and only a different part is demonstrated.
In the bearing device 10 of the first embodiment, the main body portion 61 of the first retainer 60 is disposed on the outer side in the axial direction, and the main body portion 61 of the second retainer 70 is disposed on the inner side in the axial direction (see FIG. 2). ).
On the other hand, like the bearing device 410 according to the fourth embodiment shown in FIG. 17, the main body 61 of the first retainer 60 and the main body 61 of the second retainer 70 are respectively arranged on the inner side in the axial direction. Also good.

  The main body 61 of the first retainer 60 and the main body 61 of the second retainer 70 have a thickness in the axial direction in order to hold the rolling elements 35. Therefore, the thinning (shortening in the axial direction) of the bearing device 410 is limited by the main body 61 of the first retainer 60 and the main body 61 of the second retainer 70. Here, in the bearing device 10 according to the first embodiment shown in FIG. 2, a region inside the axial direction from the claw portion 63 of the first retainer 60 is a dead space. Therefore, as shown in FIG. 17, the main body 61 of the first retainer 60 is disposed on the inner side in the axial direction, so that the bearing device 410 is thinned (shortened in the axial direction) by the main body 61 of the first retainer 60. Can be prevented from being restricted. Thereby, the bearing device 410 can be made as thin as possible.

  The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.

  In the first embodiment, the bearing device 10 is applied as the pivot shaft of the arm 8 of the information recording / reproducing apparatus 1. However, the application of the bearing device 10 is limited to the pivot shaft of the arm 8 of the information recording / reproducing apparatus 1. Not. For example, the bearing device 10 may be applied as the rotating shaft of the spindle motor 7 that rotates the disk D of the information recording / reproducing apparatus 1, or the bearing device 10 is applied as the rotating shaft of the polygon mirror for scanning the laser light source. May be.

  In the second modification of the first embodiment, the inner end 31 b of the first outer ring 31 and the inner end 41 b of the second outer ring 41 are connected to the inner end 36 b of the first inner ring 36 and the inner side of the second inner ring 46. It was arrange | positioned in the axial direction outer side rather than the edge part 46b (refer FIG. 13). On the other hand, it is good also as a structure which abuts the inner side edge part 36b of the 1st inner ring | wheel 36, and the inner side edge part 46b of the 2nd inner ring | wheel 46, without providing the spacer 55. FIG. As a result, a preload is applied to the first outer ring 31 and the second outer ring 41 while providing a gap between the inner end 31 b of the first outer ring 31 and the inner end 41 b of the second outer ring 41 without providing the spacer 55. Since it can be added, the cost and weight can be reduced by reducing the number of parts.

The shapes of the shafts 20 and 220 are not limited to the first embodiment to the fourth embodiment. For example, the shaft 20 of the first embodiment has the flange portion 20a formed on one side in the axial direction, but the flange portion 20a may not be formed.
Moreover, the shape of the 1st retainer 60 and the 2nd retainer 70, the arrangement | positioning number of the rolling elements 35, etc. are not limited to 1st embodiment.

  Moreover, you may combine each modification of each embodiment and 1st embodiment suitably, respectively. For example, the first modification of the first embodiment is combined with the third embodiment, and the outer end portion in the axial direction of the inner ring 336 is disposed on the inner side of the outer end portions 50a and 50b of the sleeve 50, and The inner ring 336 may be formed by integrally forming the first inner ring 36 and the second inner ring 46.

  In each embodiment and each modification of the first embodiment, the first retainer 60 and the second retainer 70 are provided. However, the inner ring rolling surface can be used without using the first retainer 60 and the second retainer 70. A plurality of rolling elements 35 may be disposed between 39 and 49 and the outer ring rolling surfaces 34 and 44. At this time, in the manufacturing process of the bearing device 10, the retainer holding step S13 is not necessary, and the rolling elements 35 are held by a jig or the like, whereby the first rolling element arrangement step S15 and the second rolling element arrangement step. S21 can be performed.

  In each embodiment and each modification of the first embodiment, the first outer ring 31 and the second outer ring 41 are moved in a state where the first outer ring 31 and the second outer ring 41 are relatively pressed along the axial direction. A so-called fixed position preload that applies a preload by being fixed to the sleeve 50 has been adopted. On the other hand, for example, a so-called constant pressure preload is used in which a biasing member is provided and a preload is applied by holding the first outer ring 31 and the second outer ring 41 while being relatively pressed along the axial direction. May be.

  Further, the inner ring rolling surfaces 39 and 49 and the outer ring rolling surfaces 34 and 44 in each embodiment and each modification example of the first embodiment are formed in curved shapes in which the outer radius and the inner radius gradually change, respectively. On the other hand, for example, the inner ring rolling surfaces 39 and 49 and the outer ring rolling surfaces 34 and 44 may partially include a plane portion.

  In addition, it is possible to appropriately replace the components in the above-described embodiments with known components without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1 ... Information recording / reproducing apparatus 2 ... Slider 8 ... Arm (rotating member) 9 ... Housing 10, 210, 310, 410 ... Bearing apparatus 20, 220 ... Shaft 30 ... 1st rolling bearing part (rolling bearing part) 31 ... 1st outer ring (outer ring) 31a ... Outer end part 31b ... Inner end part 34 ... Outer ring rolling surface 35 ... Rolling element 36 ... first inner ring (inner ring) 36a ... outer end 39 ... inner ring rolling surface 40 ... second rolling bearing part (rolling bearing part) 41 ... second outer ring (outer ring) 41a .... Outer end 41b ... Inner end 44 ... Outer ring rolling surface 46 ... Second inner ring (inner ring) 46a ... Outer end 49 ... Inner ring rolling surface 50 ... Sleeve 50a: One outer end (outer end) 50b: Other outer end (Outer end) 336 ... inner ring D ... disk (magnetic recording medium) K1 ... first separation distance K2 ... second separation distance F1 ... virtual surface F2 ... virtual surface S11 .. First outer ring arranging step S13 ... Retainer holding step S15 ... First rolling element arranging step S17 ... First inner ring arranging step S19 ... Second inner ring arranging step S21 ... Second rolling element Arrangement step S23 ... Second outer ring arrangement step S25 ... Preload application step

Claims (12)

A shaft,
A pair of rolling bearing portions arranged side by side in the axial direction of the shaft;
With
The pair of rolling bearing portions are respectively arranged between an inner ring disposed coaxially with the central axis of the shaft, an outer ring surrounding the inner ring from the outside in the radial direction of the shaft, and between the inner ring and the outer ring. A plurality of rolling elements held movably,
The separation distance between the innermost part of the rolling element in the radial direction and the central axis is a first separation distance, and the separation distance between the outermost part of the rolling element in the radial direction and the central axis is a second separation distance , When the direction going between the pair of rolling bearing portions in the axial direction is the inside of the axial direction, and the direction away from between the pair of rolling bearing portions in the axial direction is the outside of the axial direction ,
Each of the inner rings of the pair of rolling bearing portions is formed such that an outer radius of the outer end portion in the axial direction is smaller than the first separation distance, and the first inner side is directed from the outer side to the inner side in the axial direction. It has an inner ring rolling surface formed so that the outer radius is larger than the separation distance,
Each of the outer rings of the pair of rolling bearing portions is formed such that an inner radius of an inner end portion in the axial direction is larger than the second separation distance, and the second outer radius extends from the inner side to the outer side in the axial direction. A bearing device comprising an outer ring rolling surface formed to have an inner radius smaller than a separation distance. The bearing device according to claim 1,
The axially outer end portion of the inner ring is disposed on the inner side in the axial direction with respect to the outer end portion of the outer ring in the axial direction. The bearing device according to claim 1 or 2,
The distance from the virtual surface including the centers of the plurality of rolling elements to the inner end portion in the axial direction of the outer ring is shorter than the distance from the virtual surface to the outer end portion in the axial direction of the outer ring. A bearing device characterized by being formed. The bearing device according to any one of claims 1 to 3,
At least one of the inner rings of the pair of rolling bearing portions and the shaft are integrally formed with each other. The bearing device according to any one of claims 1 to 4,
An inner ring of the pair of rolling bearing portions is integrally formed with each other. The bearing device according to any one of claims 1 to 5,
The inner ring and the outer ring are formed by forging. The bearing device according to any one of claims 1 to 6,
A retainer that is arranged between the inner ring and the outer ring and that can hold the plurality of rolling elements in a freely rolling manner and can be arranged in an annular shape;
The retainer is
The main body,
A plurality of pairs of claws that are erected from the main body along the axial direction and hold the rolling elements in a freely rollable manner;
With
A bearing device, wherein the main body portion is disposed inside the axial direction with respect to the rolling elements. The bearing device according to any one of claims 1 to 7,
The pair of rolling bearing portions includes a cylindrical sleeve to which the outer ring is inserted and fixed . The bearing device according to claim 8,
The bearing device, wherein the outer rings of the pair of rolling bearing portions are fixed to the sleeve in a state in which a preload is applied relative to each other. The bearing device according to claim 8 or 9, wherein
The bearing device according to claim 1, wherein an outer end portion of the sleeve in the axial direction is arranged on an inner side in the axial direction of the outer end portion of the outer ring in the axial direction. It is a manufacturing method of the bearing device according to claim 1, Comprising:
A first outer ring arranging step of inserting a first outer ring of the pair of rolling bearing portions into a sleeve and fixing the outer ring to one side in the axial direction of the sleeve;
A retainer holding step in which each of the first retainer and the second retainer capable of holding the rolling elements is configured to hold the plurality of rolling elements such that the rolling elements can freely roll and are arranged in an annular manner; and
A first rolling element in which the plurality of rolling elements are inserted into the first outer ring from the other side in the axial direction together with the first retainer, and the plurality of rolling elements are placed on the outer ring rolling surface of the first outer ring. Moving object placement process;
A first inner ring arrangement step in which a first inner ring is arranged inside the first outer ring among the inner rings of the pair of rolling bearing portions, and an inner ring rolling surface of the first inner ring is brought into contact with the plurality of rolling elements; ,
A second inner ring arrangement step of arranging a second inner ring on the other side in the axial direction among the inner rings of the pair of rolling bearing portions;
A second rolling element in which the plurality of rolling elements are inserted into the second inner ring from the other side in the axial direction together with the second retainer, and the plurality of rolling elements are placed on the inner ring rolling surface of the second inner ring. Placement process;
A second outer ring arranging step of inserting a second outer ring into the sleeve among the outer rings of the pair of rolling bearing portions and arranging the second outer ring on the other side in the axial direction;
A preloading step of fixing the second outer ring to the sleeve while relatively pressing the first outer ring and the second outer ring along the axial direction;
A method for manufacturing a bearing device, comprising: A bearing device according to claim 1;
A housing that supports one end of the bearing device;
A rotation member that is externally fitted to the outer ring and rotates about the central axis of the shaft;
A slider mounted on the rotating member for recording and reproducing information with a magnetic recording medium;
An information recording / reproducing apparatus comprising:

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