JPH07167151A - Double row rolling bearing device with preload - Google Patents

Abstract

PURPOSE:To prevent distortion of an inner ring raceway accompanying fitting the inner ring outside a shaft so as to obtain high bearing accuracy. CONSTITUTION:A small diameter part 31 and a large diameter part 32 are formed on the inner circumferential face of an inner ring 27 putting a recessed groove 30 there between. An inner ring raceway 29 is formed on the outer circumference of the large diameter part 32. The inner ring 27 is fitted outside a shaft 26 at the small diameter part 31. Even if the small diameter part 31 is distorted accompanying outside fitting, the distortion hardly reaches the large diameter part 32, and the inner ring raceway 29 is hardly distorted. Consequently, high bearing accuracy can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a hard disk drive (HD) for a video tape recorder (VTR), for example.
D), a laser beam printer (LBP) spindle motor, a rotary actuator, a rotary encoder, and the like, and a rolling bearing device that is incorporated in various precision rotating parts to support the rotating parts.

[0002]

2. Description of the Related Art A ball bearing is used in order to rotatably support a VTR or HDD spindle while preventing whirling motion (motion in a direction perpendicular to the axis) and axial runout. Used a pair of independent ball bearings (deep groove type or angular type). Further, in order to improve the efficiency of the assembling work of the ball bearing to the rotation supporting portion, it has been considered to use a double row ball bearing.

The double-row ball bearing is, as shown in FIG.
Shaft 2 having a pair of deep groove type inner ring raceways 1 and 1 on the outer peripheral surface
And an outer ring 4 having a pair of deep groove type outer ring raceways 3 and 3 on the inner peripheral surface thereof, as shown in FIG. 2B, are concentrically combined as shown in FIG. A plurality of balls 5, 5 are provided between the inner ring raceways 1, 1 and the outer ring raceways 3, 3, respectively.
It is configured by being mounted so that it can roll freely. Incidentally, FIG.
(C) 6 and 6 are cages for holding the balls 5 and 5 at equal intervals in the circumferential direction, and 7 and 7 are intended to prevent dust and the like from entering the ball 5 and 5 mounting portions. It is a sticker for.

The double-row deep groove type ball bearing as shown in FIG. 5 (C) has a conventionally known structure.
In the past, it was difficult to manufacture HDDs that can support HDD spindles. This is for the following reason.

The ball bearing for supporting the spindle of the VTR or HDD must be extremely highly precise in order to prevent whirling motion and axial runout. Therefore, the ball bearing for supporting the spindle is used in a state where a preload in the axial direction is applied.

On the other hand, when the balls 5, 5 are mounted between the inner ring raceway 1 and the outer ring raceway 3 in order to assemble a deep groove type ball bearing, as shown in FIG. 6, the inner ring raceway 1 and the outer ring raceway are mounted. 3 is made eccentric, and a gap 8 extending in the circumferential direction between these two raceways 1, 3 is enlarged in part, and from the enlarged portion of this gap 8 between the inner ring raceway 1 and the outer ring raceway 3 Then, a predetermined number of balls 5 and 5 are inserted. After that, the inner ring raceway 1 and the outer ring raceway 3 are made concentric, and the predetermined number of balls 5, 5 are
Are arranged at equal intervals in the circumferential direction.

In this way, when rearranging the plurality of balls 5 and 5 inserted into a part in the circumferential direction at equal intervals in the circumferential direction, the balls 5 and 5 are moved to the inner ring raceway 1 and It must be slid against the outer raceway 3. At this time, when the inner ring raceway 1 and the outer ring raceway 3 are in a state of strongly pressing the balls 5 and 5 (preloading state), the inner ring raceway 1, the outer ring raceway 3 and the balls 5 and 5 are rolled. The surface is easily scratched, and when scratched, problems such as vibration during rotation and deterioration of durability occur.

On the other hand, for example, Japanese Patent Laid-Open No. 57-200.
As described in Japanese Patent No. 722, in the case of a structure in which a pair of single-row deep groove type ball bearings are provided with a space between each other, the ball bearings can be assembled in a state where no preload is applied. There is no inconvenience, but the work of assembling the ball bearing is troublesome.

Further, for example, JP-A-61-65913, JP-A-61-79899 and JP-A-50-1017.
No. 53 and No. 56-127456 are used for tension pulleys or water pumps.
Double-row deep groove ball bearings are described, but none of these require a high degree of rotational accuracy.
It is used without applying preload, and is used for VTR and H
It cannot be used to support a spindle such as a DD.

Further, in Japanese Unexamined Patent Publication No. 61-145761, a double-row angular type ball bearing is disclosed in Japanese Utility Model Laid-Open No. 62-2232.
Japanese Patent Publication No. 3 discloses a double-row ball bearing in which a deep groove type ball bearing and an angular type ball bearing are combined.
However, when assembling an angular type ball bearing,
When a ball passes through the shoulder portion of the raceway surface, in order not to damage the shoulder portion and the rolling surface of the ball, for example, in Japanese Utility Model Publication No. 39-3916.
As described in the publication, it is necessary to heat and expand the outer ring, which complicates the assembly work.

Further, in Japanese Patent Publication No. 57-140912, a double row deep groove type ball bearing having an outer ring in which a main outer ring and a sub outer ring which is displaceable in the axial direction of the main outer ring are combined is described. After the assembly, the auxiliary outer ring is displaced in the axial direction to give a predetermined preload, and the auxiliary outer ring is fixed by a presser plate. The invention for performing preloading is described. However, in the case of the invention described in this publication, a retainer and a spring are required, which not only complicates parts management and assembly work, but also causes the axial length of the ball bearing to become longer than necessary.

US Pat. No. 4,900,958 discloses a structure as shown in FIGS. In the case of the structure shown in FIG. 7 among these, a pair of deep groove type (or angular type) ball bearings 9 are provided between the outer peripheral surface of the shaft 2 and the inner peripheral surface of the housing 10, and Ball bearing 9,
The inner rings 11, 11 of 9 are pressed in a direction of approaching each other to preload the balls 5, 5 of both ball bearings 9, 9.

That is, one end (right side in FIG. 7) of the inner ring 11 is abutted against the stop ring 12, and the other (left side in FIG. 7) inner ring 11 is pressed toward the stop ring 12 to preload We are giving. The other inner ring 11 is fixed to the shaft 2 with an adhesive or a shrink fit. Therefore, the other inner ring 11 has a load corresponding to the above preload until the adhesive solidifies or the heated inner ring 11 contracts.
Continue to press against the retaining ring 12.

Further, in the case of the structure shown in FIG. 8, double rows of inner ring raceways 1, 1 are formed on the outer peripheral surface of the shaft 2. A spacer 13 is sandwiched between a pair of outer rings 4 and 4 fitted in the housing 10, and the outer rings 4 and 4 are pressed by the spacer 13 in directions away from each other, thereby preloading the balls 5 and 5. is doing.

Further, in Japanese Utility Model Laid-Open No. 3-36517, as shown in FIG. 9, a leaf spring 14 sandwiched between a pair of outer rings 4 and 4 presses the outer rings 4 and 4 in directions away from each other. However, a structure for applying a preload to the balls 5 and 5 is described.

Further, Japanese Patent Application Laid-Open No. 3-222661 and US Pat. No. 5,045,738 describe structures as shown in FIGS. Among them, the structure shown in FIG. 10 applies a preload by pressing the outer ring 4 fitted in the housing 10 by the leaf spring 14, and the structure shown in FIG. 11 applies a predetermined preload. The outer ring 4 is fixed to the housing 10 with an adhesive or by shrink fitting. Of the double row outer ring raceways 3 and 3,
One outer ring raceway 3 is formed on the inner peripheral surface of the outer ring 4, and the other outer ring raceway 3 is formed on the inner peripheral surface of the housing 10.

Further, although not shown in the drawing, JP-A-61-1
In Japanese Patent No. 45761 and U.S. Pat. No. 4,713,704, one inner ring raceway of the double-row inner ring raceway is the outer peripheral surface of the shaft, and the other inner ring raceway is the outer peripheral surface of the inner ring externally fitted to this shaft. There is described a structure in which the inner ring is adhered and fixed to the shaft while being formed respectively and a proper preload is applied to the balls.

[0018]

DESCRIPTION OF THE PRESENT INVENTION However, the structure shown in FIGS. 7 to 11 and the structure described in Japanese Patent Laid-Open No. 61-145761 are troublesome to assemble and require parts management. In addition, micro vibration is likely to occur. That is,
In any of the conventional structures described above, when preload is applied, the inner ring 11 is against the shaft 2 (in the case of the structure shown in FIG. 7) or the outer ring 4 is against the housing 10 (shown in FIGS. 8 to 11). In the case of each structure), since they are loosely fitted to each other, the inner ring 11 or the outer ring 4 is likely to incline slightly even if the preload is applied. When the rolling bearing device is tilted, a slight vibration is generated when the obtained rolling bearing device is rotated, which may deteriorate the performance of an HDD or the like incorporating this bearing device.

In order to deal with such a problem, the present inventor has previously invented a double row rolling bearing device to which a preload is applied as shown in FIGS. 12 to 16 (Japanese Patent Application No. 5-44383).
In the preloaded double row rolling bearing device according to the present invention, the structure of the first example is first manufactured by the steps as shown in FIGS. 12 (A) to 12 (D). The shaft 15, which is the first member,
As shown in FIG. 3A, the small diameter portion 15a and the large diameter portion 15b are continuous at the step portion 15c, and the outer circumference of the large diameter portion 15b, which is the first peripheral surface, is moved by the first track. A certain deep groove type first inner ring raceway 16 is formed. Inner ring 1 which is the third member
7 has an inner diameter slightly smaller than the outer diameter of the small diameter portion 15a in the free state. The inner ring 17 has a deep groove type second inner ring raceway 18 which is a fourth raceway on the outer peripheral surface.

When manufacturing a rolling bearing device including the shaft 15 and the inner ring 17 as described above, first, as a first step, FIG.
As shown in (B), the inner ring 17 is externally fitted to the small-diameter portion 15a of the shaft 15 with sufficient fitting strength (strength that does not shift due to reaction force applied with preload). Then, the large diameter portion 1
The pitch P ₁ between the first inner ring raceway 16 on the outer peripheral surface of 5b and the second inner ring raceway 18 on the outer peripheral surface of the inner ring 17 is the pitch p ₁ required to apply a predetermined preload to the completed rolling bearing device.
(P ₁ > p ₁ ) longer than ((D) of FIG. 12).

Then, in a second step, the shaft 15 and the inner ring 17 combined in the first step are inserted into the cylindrical outer ring 19 which is the second member. A pair of deep groove type outer ring raceways 25, 25, which are second and third raceways, are formed on the inner circumferential surface of the outer ring 19 which is the second circumferential surface. In the second step, the pair of outer ring raceways 25, 25 are opposed to the first and second inner ring raceways 16, 18.

Next, in a third step, the shaft 15, the inner ring 17 and the outer ring 19 are eccentric, and as shown in FIG.
A part of the gap 8 extending in the circumferential direction between the pair of outer ring raceways 25, 25 and the first and second inner ring raceways 16, 18 is enlarged. Then, from the enlarged portion of the gap 8,
A predetermined number of balls 5 and 5 are inserted into the gap 8.

Next, in a fourth step, a predetermined number of balls 5, 5 inserted in the gap 8 between the pair of outer ring raceways 25, 25 and the first and second inner ring raceways 16, 18 are inserted. While moving in the circumferential direction, the balls 15 and 5 are arranged at equal intervals in the circumferential direction with the shaft 15, the inner ring 17 and the outer ring 19 being concentric.
At the same time, as shown in FIG. 12 (C), the cages 6, 6 are attached to the respective ball row portions so that the respective balls 5, 5 remain at positions at equal intervals in the circumferential direction. If necessary, seals 7, 7 are attached to the inner peripheral surfaces of both ends of the outer ring 19. In this state,
Preload has not yet been applied to each ball 5, 5.

Finally, in a fifth step, the inner ring 17 is directed toward the step portion 15c and is axially displaced on the outer peripheral surface of the shaft 15 (to the left in FIG. 12), whereby the first and second inner ring raceways are moved. 1
The pitches of 6 and 18 are shortened to the pitch p ₁ required for applying the predetermined preload. In this state, a predetermined preload is applied to the plurality of balls 5, 5 to complete the double row rolling bearing device to which the preload is applied. Even when completed, there is a gap between the step portion 15c and the end surface of the inner ring 17.

In the thus-obtained pre-loaded double-row rolling bearing device, the inner peripheral surface of the inner ring 17 and the small-diameter portion 15 are provided.
Based on the frictional force of the interference fit with the outer peripheral surface of a,
A blocking force larger than the axial load corresponding to the preload acts. Therefore, even if an adhesive is not applied between the shaft 15 and the inner ring 17, the inner ring 17 does not move and the applied preload does not disappear, and it can be handled as an integral ball bearing. Therefore, the work of forming the bearing portion of the spindle of the VTR or HDD becomes easy. Further, since the preload is applied in the axial direction, the spindle can be rotationally supported with high accuracy.

However, the inner ring 17 can be displaced with respect to the small diameter portion 15a by applying a force larger than the stopping force due to the interference fit in the axial direction. Therefore, if an appropriate force larger than the load is applied to the inner ring 17 and the inner ring 17 is displaced in the axial direction,
The preload applied to the rolling bearing device can be adjusted (increased or decreased) later.

Next, in the case of the second example shown in FIG.
After the inner ring 17a is fitted onto the small diameter portion 15a, first and second inner ring raceways 16a and 18a are formed on the outer peripheral surfaces of the shaft 15 and the inner ring 17a, respectively. By adopting such a configuration, the second inner ring raceway 18 (FIG. 12) is prevented from being distorted in a non-circular shape by fitting the inner ring 17a onto the small diameter portion 15a.

In the case of the third example shown in FIG. 14, as shown in FIG. 14A, a small diameter portion 20a and a large diameter portion 20b are formed on the inner peripheral surface of the main outer ring 20 which is the first member. Both parts 20a, 20
The step part 20c which makes b continuous is formed. Then, the auxiliary outer ring 21, which is a third member, can be fitted in the large-diameter portion 20b. On the inner peripheral surface of the sub outer ring 21 which is the third peripheral surface and the inner peripheral surface of the small diameter portion 20a which is the first peripheral surface, concave grooves 22a and 22b each having an arcuate cross section are formed over the entire circumference. Formed over time. Further, the sub outer ring 21 has an outer diameter slightly larger than the inner diameter of the large diameter portion 20b in the free state.

In the case of using the main outer ring 20 and the sub outer ring 21 to make a preloaded double row rolling bearing device,
First, as a first step, as shown in FIG. 14 (B), the sub outer ring 21 is fitted into the large diameter portion 20b with sufficient fitting strength, and as shown in FIG. 14 (C). , The groove 22
The first outer ring raceway 2 which is the first raceway is provided at the portions a and 22b.
3 and the second outer ring raceway 24 which is the fourth raceway.

As described above, in the state where the main outer ring 20 and the sub outer ring 21 are assembled, the first and second outer ring raceways 23, 24 are formed.
Therefore, the circularity of these outer ring raceways 23, 24 can be made highly accurate, and moreover, both outer ring raceways 23, 24 and the main outer ring 2 can be formed.
The amount of eccentricity with the outer peripheral surface of 0 can be suppressed to a slight extent. The pitch P ₂ between the first and second outer ring raceways 23, 24 thus formed is longer than the pitch p ₂ (FIG. 14 (E)) required to apply a predetermined preload. (P ₂ > p ₂ ).

Next, as a second step, a pair of inner ring raceways 1, which are second and third raceways, are formed on the outer circumferential surface which is the second circumferential surface.
A shaft 2 having a No. 1 (see FIG. 14D described below) is inserted into the inside of the main outer ring 20 and the sub outer ring 21 combined in the first step, and the pair of inner ring raceways 1 and 1 is formed. The first and second outer ring raceways 23, 24 are opposed to each other.

Then, in a third step, the shaft 2, the main outer ring 20 and the sub outer ring 21 are eccentric as shown in FIG. 6, and the pair of inner ring raceways 1, 1 and the first and second inner ring raceways 1 and 2. A predetermined number of balls 5, 5 are inserted into the gap 8 between the outer ring raceways 23, 24.

Next, as a fourth step, as shown in FIG. 14D, the shaft 2 and the main outer ring 20 and the sub outer ring 21 are made concentric, and the pair of inner ring raceways 1, 1 and A predetermined number of balls 5, 5 inserted between the first and second outer ring raceways 23, 24 are arranged at equal intervals in the circumferential direction. In the fourth step, the cages 6, 6 are attached to the balls 5, 5 arranged at equal intervals.
Put on.

Finally, as a fifth step, the sub outer ring 21 is axially displaced (leftward in FIG. 14) on the inner peripheral surface of the main outer ring 20 to move the sub outer ring 21 as shown in FIG. 14 (E). one,
The pitch of the second outer ring raceways 23, 24 is shortened to a pitch p ₂ required to apply a predetermined preload. In this state, a predetermined preload is applied to the plurality of balls 5, 5. Then, the seals 7 and 7a are attached to complete the rolling bearing device.

In the case of the structure for adjusting the preload by changing the pitch of the first and second outer ring raceways, as in the fourth example shown in FIG. 15, the main ring itself does not have an outer ring raceway. Outer ring 2
It is also possible to internally fit a pair of sub outer rings 21, 21a into 0A. In the case of the structure shown in FIG. 15, inner ring raceways 1 and 1 that are second and third raceways are formed on the outer peripheral surface of the inner ring 17c that is the second member. Similarly, in the case of the structure in which the preload adjustment is performed by changing the pitch of the first and second inner ring raceways, as shown in FIG.
It is also possible to externally fit 7, 17b. Each inner ring 17, 17b
On the outer peripheral surface of each of the first and second inner ring raceways 16b,
18b is formed.

[0036]

However, even in the preloaded double row rolling bearing device according to the previous invention, which is constructed and operates as described above, there are still some points to be solved as described below. was there.

That is, in the structure of the previous invention, the inner rings 17, 17a, 17 are attached to the shafts 15, 2 in order to apply a preload to each of the balls 5, 5.
b with an interference fit (Figs. 12, 13,
16), or sub outer rings 21, 21a on the main outer rings 20, 20A
Is also internally fitted (FIGS. 14 and 15) with an interference fit. At this time, the inner rings 17, 17a, 17b receive a strong diametrically outward force on their inner peripheral surfaces, and the sub-outer rings 21, 21a exert a strong diametrically inward force on their outer peripheral surfaces. receive.

If the magnitude of this force is within a predetermined range and is uniform over the entire circumference, there is no particular problem. However, the tightening margin for the interference fit is too large and the force is too large, or the roundness of the outer peripheral surfaces of the shafts 15 and 2 or the inner peripheral surfaces of the main outer rings 20 and 20A is poor. If the magnitude of the force is uneven in the circumferential direction, the inner ring raceways 18, 18 formed on the outer peripheral surfaces of the inner rings 17, 17b will be described.
b, or the outer ring raceways 23, 24 formed on the inner peripheral surfaces of the sub outer rings 21, 21a are deformed.

Due to these causes, the inner ring raceways 18, 18b, 1
6b or the outer ring raceways 23, 24 are deformed, the inner ring 1
7, 17a, 17b, or the double row ball bearing including the sub outer rings 21, 21a is deteriorated in rotational accuracy, particularly non-rotational synchronous runout. As shown in FIG. 13, the small diameter portion 1 of the shaft 15
In the case of the structure in which the inner ring 17a is externally fitted to the 5a and then the inner ring raceway 18a is formed on the outer peripheral surface of the inner ring 17a, or as shown in FIG.
As shown in FIG. 4, after the sub outer ring 21 is fitted in the main outer ring 20,
In the case of the structure in which the outer ring raceway 24 is formed on the inner peripheral surface of the sub outer ring 21, the deformation of the inner ring raceway 18a or the outer ring raceway 24 can be suppressed to a small extent, but the manufacturing work becomes troublesome.
Also in the case of the structure shown in FIGS. 13 and 14, the balls 5,
In order to move the inner ring 17a or the sub outer ring 21 in the axial direction after the assembly of 5, the inner ring 17a or the outer ring raceway 24
However, there is a possibility of deformation, albeit slightly.

The preloaded double row rolling bearing device of the present invention was invented in view of the above-mentioned circumstances.

[0041]

The preload-applied double-row rolling bearing device of the present invention has a first circumferential surface similar to that of the preload-applied double-row rolling bearing device according to the above-mentioned prior invention. A first member having, and arranged concentrically with the first member,
A second member having a second peripheral surface facing the first peripheral surface, a first track formed on the first peripheral surface, and a part of the second peripheral surface A second orbit formed in a portion facing the orbit of, and a third orbit formed in the second peripheral surface at a portion axially displaced from the second orbit,
The first member with sufficient fitting strength, the first,
A third member supported concentrically with the second member and having a third peripheral surface facing the second peripheral surface, and a part of the third peripheral surface facing the third track. A plurality of balls are provided between the fourth orbit and the fourth orbit formed in the portion to be formed, and between the first and second orbits, and between the third and fourth orbits. With. By adjusting the fitting depth of the third member with respect to the first member, a proper preload is applied to the plurality of balls.

Further, in the preloaded double row rolling bearing device of the present invention, at least the fourth peripheral surface of the third member is located on the diametrically opposite side to the third peripheral surface. The surface includes a fitting peripheral surface that fits into the first peripheral surface by an interference fit, and a non-fitting peripheral surface that does not fit into the first peripheral surface. The fourth track is formed at a position diametrically aligned with the non-fitting peripheral surface.

[0043]

In the case of the preloaded double-row rolling bearing device of the present invention configured as described above, the fourth orbit formed on the third member is unlikely to be distorted, and is based on the strain of the fourth orbit. It is possible to prevent deterioration of rotation accuracy.

[0044]

FIG. 1 shows a first embodiment of the present invention.
A pair of inner rings 27, 27 is provided on the outer peripheral surface of the shaft 26 by sufficient reaction force (reaction force based on the applied preload).
It has been fitted with enough strength to prevent it from moving. A cylindrical outer ring 28 is arranged around each of the inner rings 27, 27 concentrically with the shaft 26 and the inner rings 27, 27.

One inner ring raceway 29, 29 is formed on the outer peripheral surface of each inner ring 27, 27. or,
Recessed grooves 30, 30 are formed over the entire circumference on the inner peripheral surface of the intermediate portion of each inner ring 27, 27, which is the fourth peripheral surface. Then, on the inner peripheral surfaces of the inner rings 27, 27, the concave grooves 30,
Small-diameter portions 31, 31 are formed on one side of 30.
The inner peripheral surface of each of the small-diameter portions 31, 31 serves as a fitting peripheral surface that is fitted onto the outer peripheral surface of the shaft 26 with an interference fit. That is, the inner rings 27, 27 are externally fitted and fixed to the shaft 26 at the small diameter portions 31, 31 with sufficient fitting strength.

Large-diameter portions 32, 32 are formed on the inner peripheral surfaces of the inner rings 27, 27 at positions on the other side of the concave grooves 30, 30. The inner peripheral surface of each of these large diameter portions 32, 32 is
It is a non-fitting peripheral surface that does not fit with the outer peripheral surface of the shaft 26. That is, the inner circumference of each of the small diameter portions 31, 31 and the shaft 2
There is a gap between the inner peripheral surface of each of the large diameter portions 32, 32 and the outer peripheral surface of the shaft 26 in a state where the outer peripheral surface of 6 is fitted with an interference fit. Then, the inner ring raceways 29,
29 is formed around the large diameter portions 32, 32.

Since the inner rings 27, 27 are constructed in this manner, the roundness of the outer peripheral surface of the shaft 26 onto which the inner rings 27, 27 are fitted is poor, or the inner rings 27, 27 are fitted to the shaft 26. The tightening margin when fitting the outer ring to the
Even when the fitting portion of 27, that is, the small-diameter portion 31, 31 forming portion is distorted, this distortion causes the inner ring raceway 29,
It doesn't extend to 29 parts. Therefore, each inner ring 2
It is possible to sufficiently prevent distortion of the inner ring raceways 29, 29 formed in 7, 27, and obtain a double row ball bearing having high rotation accuracy.

After the balls 5, 5 are assembled in a state where the pitch of the inner ring raceways 29, 29 is set to be slightly larger, at least one inner ring 27 is axially displaced to apply a preload to the balls 5, 5. Except for the point of preventing distortion of the inner ring raceways 29, 29, it is the same as the above-described preload-applied double row rolling bearing device. The present invention applies the present invention to the structure shown in FIG. 16 of the prior invention. Therefore, the same parts as those of the structure shown in FIG.

Next, FIG. 2 shows a second embodiment of the present invention. In the case of this embodiment, when the outer ring 19a is internally fitted and fixed to another member such as a housing, the outer ring raceways 25 formed on the inner peripheral surface of the outer ring 19a are prevented from being distorted. . The outer ring raceway 25, and the outer ring raceway 25 are respectively provided at two positions on the inner peripheral surface of the outer ring 19a which are axially separated from each other.
25 are formed. Further, in the case of the present embodiment, the inner circumferential surface of the outer ring 19a is located between the double-row outer ring raceways 25, 25, and the entire circumference of the inner circumferential surface of the outer ring 19a is 1
The pair of concave grooves 33, 33 are formed separately in the axial direction.

When the outer ring 19a is internally fitted and fixed to another member such as a housing or a rotary hub so as to form a rotation support portion of a spindle of an HDD or VTR, the other member and the outer ring 19a are , The pair of concave grooves 33, 33
It fits at the portion 34 between. Therefore, in a state where the outer ring 19a is fitted in and fixed to another member, there is some gap between the outer peripheral surface of both axial ends of the outer ring 19a and the inner peripheral surface of the other member. Become.

In order to regulate the fitting position in this manner, the outer diameter of the outer ring 19a is made slightly larger than the both end portions at the interstitial portion 34, or at the inner peripheral surface of the other member. The inner diameter of the portion fitted with the interspace portion 34 is made slightly smaller than the inner diameters of the other portions. In the case of reducing the inner diameter, when the portion passes through the portion where one outer ring raceway 25 is formed,
The outer ring raceway 25 may be elastically deformed, but is restored after passing.

In the case of this embodiment, the rigidity of the outer ring 19a becomes low at the portion where the pair of concave grooves 33, 33 are formed. Therefore, even if the portion 34 between the pair of recessed grooves 33, 33 is slightly deformed due to fitting with another member such as a housing, this deformation will exceed the recessed grooves 33, 33 and cause the deformation. It becomes difficult to reach the outer ring raceways 25, 25 forming portion. As a result, the outer ring raceways 25, 25 hardly deform,
It is possible to secure the rotation accuracy of the double-row ball bearing incorporating the outer ring 19a.

In particular, in the case of the structure shown in FIG. 2, the gap portion 34 is formed thick so that the gap portion 34 has high rigidity and is hard to be deformed. Therefore, the effect of preventing distortion of the outer ring raceways 25, 25 is further improved. Other configurations and operations are the same as those in the first embodiment described above, and therefore, the same reference numerals are given to the same portions and duplicate description will be omitted.

Next, FIG. 3 shows a third embodiment of the present invention. In the case of the present embodiment, the present invention is applied to a double row rolling bearing device incorporated in an electric motor for HDD. The base end of the shaft 15 is fitted and fixed to the center of the housing 35. An inner ring 27a is externally fitted and fixed to the small diameter portion 15a of the shaft 15. A small-diameter portion 31 and a large-diameter portion 32 are formed on the inner peripheral surface of the inner ring 27a, sandwiching the groove 30, as in the first embodiment described above. Then, the inner ring 27a is connected to the small-diameter portion 31 of the shaft 15 by the small-diameter portion 31 of the shaft 15.
It is externally fitted and fixed to 5a.

An outer ring 28a is arranged around the shaft 15 and the inner ring 27a concentrically with the shaft 15 and the inner ring 27a. The inner peripheral surface of the outer ring 28a has a large diameter portion 36 located around the inner ring 27a and the large diameter portion 1 of the shaft 15.
It has a shape in which a small-diameter portion 37 located around 5b is connected by an inclined portion 38. Further, small-diameter balls 5a and 5a are provided between the inner ring raceway 29a formed on the outer peripheral surface of the large diameter portion 15b and the outer ring raceway 25a formed on the small diameter portion 37. Large diameter balls 5b and 5b are provided between the inner ring raceway 29b formed on the outer peripheral surface of the inner ring 27a and the outer ring raceway 25b formed on the large diameter portion 36.

The outer ring 28a is internally fitted and fixed to a support cylindrical portion 40 formed at the center of a hub 39 for supporting the hard disk. The inner peripheral surface of the support cylindrical portion 40 has a shape in which a large-diameter portion and a small-diameter portion are continuous in steps so as to match the outer peripheral surface of the outer ring 28a. By forming each peripheral surface that fits each other in this way, these peripheral surfaces do not slide over their entire length during the fitting work, and the fitting work efficiency can be achieved. .

A rotor 41 is provided on the inner peripheral surface of the hub 39.
The stators 42 facing the inner peripheral surface of the rotor 41 are fixed to the housing 35 to form an electric motor 43 for rotating the hub 39. Other configurations and actions, such as preventing the inner ring raceway 29b from being deformed when the inner ring 27a is fitted onto the small diameter portion 15a, are similar to those of the first embodiment described above.

Next, FIG. 4 shows a fourth embodiment of the present invention. In the case of the present embodiment, the outer ring 19a is configured by abutting the end faces of the small-diameter outer ring element 44a and the large-diameter outer ring element 44b with each other via the spacer 45. Such an outer ring 19a is fitted in the supporting cylindrical portion 40 (FIG. 3) of the hub 39 as used in the third embodiment described above.

In the case of the present embodiment, the efficiency of the work of fitting the outer ring 19a into the supporting cylindrical portion 40 can be improved, as in the third embodiment described above. Also, the deformation of the inner ring raceways 29, 29 on the outer peripheral surfaces of the inner rings 27, 27 fitted and fixed to the shaft 26 can be prevented, as in the first and second embodiments described above.

Although not shown, the present invention is shown in FIG.
The secondary outer ring 2 is attached to the primary outer ring 20, 20A as shown in FIGS.
The outer ring raceway 2 is applied to the structure in which the inner parts 1 and 21a are fitted and fixed.
It is also possible to prevent deformation of 3 and 24. In this case,
A large diameter portion that constitutes a fitting peripheral surface and a small diameter portion that constitutes a non-fitting peripheral surface are formed on the outer peripheral surface of each of the sub outer rings 21, 21a. A groove is formed between the large diameter portion and the small diameter portion, if necessary.

[0061]

Since the double-row rolling bearing device to which the preload is applied according to the present invention is configured as described above, the raceway is deformed based on the fitting while securing the effects of the above-mentioned invention. Can be prevented, and a double row ball bearing having high rotation accuracy can be obtained.

[Brief description of drawings]

FIG. 1 is a sectional view showing a first embodiment of the present invention.

FIG. 2 is a sectional view showing the second embodiment.

FIG. 3 is a sectional view showing the third embodiment.

FIG. 4 is a sectional view showing the fourth embodiment.

FIG. 5 is a cross-sectional view showing components and a finished product of a rolling bearing device which has been conventionally considered.

FIG. 6 is a view showing a state in which an outer ring raceway and an inner ring raceway are eccentric to insert a ball.

FIG. 7 is a half sectional view showing a first example of a conventional structure.

FIG. 8 is a half sectional view showing the second example.

FIG. 9 is a sectional view showing the third example.

FIG. 10 is a half sectional view showing the fourth example.

FIG. 11 is a sectional view showing the fifth example.

FIG. 12 is a cross-sectional view showing, in the order of steps, a state in which the first example of the preload-applied double-row rolling bearing device of the previous invention is assembled.

FIG. 13 is a cross-sectional view showing the second example in the order of steps.

FIG. 14 is a half sectional view showing the third example in the order of steps.

FIG. 15 is a half sectional view showing the fourth example in the order of steps.

FIG. 16 is a half sectional view showing the fifth example in the order of steps.

[Explanation of symbols]

 1 inner ring raceway 2 shaft 3 outer ring raceway 4 outer ring 5, 5a, 5b ball 6 cage 7, 7a seal 8 gap 9 ball bearing 10 housing 11 inner ring 12 retaining ring 13 spacer 14 leaf spring 15 shaft 15a small diameter portion 15b large diameter portion 15c Step portion 16, 16a, 16b First inner ring raceway 17, 17a, 17b, 17c Inner ring raceway 18, 18a, 18b Second inner ring raceway 19, 19a Outer ring 20, 20A Main outer ring 20a Small diameter portion 20b Large diameter portion 20c Step portion 21, 21a Secondary outer rings 22a, 22b Recessed groove 23 First outer ring raceway 24 Second outer ring raceway 25, 25a, 25b Outer ring raceway 26 Shaft 27, 27a Inner ring 28, 28a Outer ring 29, 29a, 29b Inner ring raceway 30 Recessed groove 31 Small diameter part 32 Large diameter part 33 Recessed groove 34 Inter-part 35 Housing 36 Large diameter part 37 Small diameter part 38 Inclined part 39 Hub 4 Support cylindrical portion 41 rotor 42 stator 43 electric motor 44a, 44b outer race element 45 spacer

Claims (1)

[Claims] 1. A first member having a first peripheral surface, and a second member arranged concentrically with the first member and having a second peripheral surface facing the first peripheral surface. , A first track formed on the first peripheral surface, a second track formed on a portion of the second peripheral surface facing the first track, and the second track A third track formed on the second peripheral surface at a portion axially displaced from the first member with sufficient fitting strength, and concentric with the first and second members. A third member that is supported and has a third peripheral surface that faces the second peripheral surface, and a third member that is formed at a portion of the third peripheral surface that faces the third track. Four orbits, a plurality of balls provided between the first and second orbits, and between the third and fourth orbits, respectively, Part of A preload-applied double-row rolling bearing device in which a proper preload is applied to each of the plurality of balls by adjusting a fitting depth of the third member with respect to a material, The fourth peripheral surface existing on the diametrically opposite side to the third peripheral surface of the peripheral surface of the member is
The first peripheral surface includes a fitting peripheral surface that is fitted by an interference fit, and a non-fitting peripheral surface that does not fit with the first peripheral surface. Double-row rolling bearing device formed at a position diametrically aligned with the non-fitting peripheral surface of.