JP2002317819A - Preload applying device for double row rolling bearing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate adjusting work and enhance its accuracy of a preload applied to a double row ball bearing device 1a by providing adjustment in a desired manner of force axially pressing a bearing ring composing the double row ball bearing device 1a. SOLUTION: A first rotary shaft 15 coupling and fixing a holder 11a holding a shaft 2 and a second rotary shaft 30 coupling and fixing a pushing arm 12a axially pressing the bearing ring are rotatably supported respectively to first and second support members 16 and 31 by first and second support bearing devices 17 and 32. Load carrying capacities of the support bearing devices 17 and 32 are provided sufficiently larger (for example, ten times or more) than a load carrying capacity of the double row ball bearing device 1a to be applied with the preload.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The preload applying device for a double row rolling bearing device according to the present invention is, for example, a flexible disk drive (FDD), a hard disk drive (HDD), an optical disk storage, a laser beam printer (LBP), and a tape. This rotary part is supported by incorporating it into various precision rotating parts such as a spindle motor incorporated in a streamer, a video tape recorder (VTR), a cooling fan driving motor of an IC (integrated circuit), or a base end of a swing arm of an HDD. To apply an appropriate preload to a double row rolling bearing device such as a double row ball bearing device.

[0002]

2. Description of the Related Art FIGS. 6 and 7 show an example of a double-row ball bearing device incorporated in various kinds of precision rotating parts as described above and supporting the rotating parts, which is described in Japanese Patent Application Laid-Open No. Hei 6-221326. Showing things. In the double row ball bearing device 1 described in this publication, a shaft 2 constituting an inner member and an outer cylinder 3 constituting an outer member, which are arranged concentrically, are rotatable by a pair of ball bearings 4, 4. Combined. Each of these ball bearings 4, 4 has a deep groove type inner raceway 5 formed on the outer peripheral surface, an inner race 6 which is a raceway member constituting an inner member, and a deep groove type outer raceway 7 formed on the inner peripheral surface. A plurality of balls 10, 10 each of which is a rolling element, each of which is provided so as to roll freely while being held by a retainer 9 between an outer ring 8 constituting an outer member and the inner ring track 5 and the outer ring track 7. Consisting of Each of the outer races 8, 8 constituting each of the ball bearings 4, 4 is internally fixed to the inner peripheral surface of the outer cylinder 3, and the inner races 6, 6 are respectively fixed to the outer peripheral surface of the shaft 2. It is externally fitted and fixed.

The double-row ball bearing device 1 constructed as described above
In order to secure rigidity and rotational accuracy required for the double-row ball bearing device 1, the inner races 6, 6 are pressed in directions approaching each other so that the balls 10, 10, 10
Is given a predetermined preload. In the case of the illustrated example, the operation of applying the preload to each of the balls 10, 10 is performed as follows. First, the shaft 2 is held by a holding member 11 as a holding member, and one inner ring 6 is attached to the outer end surface of one (right side in FIG. 6) inner ring 6 by the other (left side in FIG. 6). The distal end face of the pushing arm 12, which is a pushing member that can be pushed toward 6, is pressed. Further, one end of the yarn 13 constituting the loss torque measuring means is wound around the outer peripheral surface of the outer cylinder 3.

[0004] Then, the shaft 2 is rotated at a predetermined speed by the holder 11, and the rotational torque (loss torque) of the outer cylinder 3 that is to rotate with the shaft 2 is applied to the yarn 1.
3 is measured by a load sensor 14 attached to the other end of the motor 3 and constituting a loss torque measuring means. Further, by pressing the outer end surface of the one inner ring 6 by the pushing arm 12 while measuring the loss torque in this manner, the one inner ring 6 is displaced toward the other inner ring 6. Then, when the loss torque substantially matches the preset value, the pushing arm 12 is stopped, and the displacement operation of the one inner ring 6 is completed.

It is conventionally known that there is a certain relationship between the loss torque and the magnitude of the preload of the double row ball bearing device 1 as described above. Therefore, if the loss torque of the double-row ball bearing device having the same configuration as that of the double-row ball bearing device 1 to which a predetermined preload should be applied and the appropriate preload has been applied is measured in advance, one of the two In a state where the displacement operation of the inner ring 6 has been completed, an appropriate preload can be applied to the balls 10 and 10.
The inner rings 6, 6 are fixed to the shaft 2 by bonding or by tight fitting with sufficient fitting strength (strength that does not shift due to the reaction force of the preload). Each inner ring 6,
When the adhesive 6 is fixed to the shaft 2, the one inner ring 6 is continuously pressed by the pushing arm 12 with a load corresponding to the appropriate preload until the adhesive is solidified.

[0006]

In order to properly perform the preloading operation as described above, it is necessary to provide a preloading device for performing the preloading operation with desired performance. That is, in the case of a small double-row ball bearing device 1 to be incorporated in an HDD or the like, in order to keep the magnitude of the preload within an appropriate range, a force for pressing the one inner ring 6 toward the other inner ring 6 is delicate. Need to be adjusted. Therefore, if the pressing force cannot be adjusted as desired (for example, a load change (stick slip) occurs when the one inner ring 6 is moved in the axial direction), the preload is kept within an appropriate range. Things get harder. For this reason, it is preferable that the preloading device has a performance capable of adjusting the pressing force as desired. On the other hand, the above-mentioned Japanese Patent Application Laid-Open No. 6-221326 does not describe specific means for making the preloading device have the above-described performance. The preload applying device for a double row rolling bearing device according to the present invention has been invented in view of the above-described circumstances.

[0007]

A double-row rolling bearing device for applying a desired preload by the preloading device of the double-row rolling bearing device according to the present invention is the double-row ball bearing device shown in FIGS. As in the double row rolling bearing device such as 1 etc., an inner member,
A pair of inner raceways provided on the outer peripheral surface of the inner member at a distance from each other; an outer member disposed concentrically with the inner member around the inner member; A pair of outer ring tracks provided at positions facing the track,
A plurality of rolling elements are provided between each of the outer raceways and each of the inner raceways so as to freely roll. And
The preload applying device of the double-row rolling bearing device of the present invention includes a raceway member having an inner raceway formed on the outer peripheral surface thereof to constitute the inner member, as in the case of the conventional device described above, and the inner raceway and another inner raceway. The double row rolling is performed by rotating the inner member at a predetermined speed with respect to the outer member so as to apply a desired preload to each of the rolling elements by displacing in the axial direction so as to reduce the distance from the track. While measuring the loss torque of the bearing device, the track member is displaced in the axial direction, and in a state where the loss torque substantially coincides with a predetermined value set in advance, the displacement operation in the axial direction of the track member is completed. A method for applying a preload to a rolling bearing device is performed. For this purpose, a holding member that is rotatable while holding the inner member, and a pressing member that is capable of axially pressing the track member in order to axially displace the track member and that is rotatable together with the track member When rotating the inner member at a predetermined speed by rotating one of the pressing member and the holding member, the outer member is held substantially stationary. And a loss torque measuring means capable of measuring the loss torque.

[0008] In particular, in the preloading device of the double row rolling bearing device of the present invention, the load capacity of the double row rolling bearing device is determined with respect to the supporting member which does not rotate the holding member and the pressing member. Are rotatably supported by a support bearing device having a large load capacity. In this case, preferably, the load capacity of each of the support bearing devices is set to be at least ten times the load capacity of the double row rolling bearing device.

Further, in the case of the preloading device for a double row rolling bearing device according to the third aspect, one of the holding member and the pressing member is constituted by an output shaft of a motor. ing.

[0010]

According to the preloading device for a double-row rolling bearing device of the present invention having the above-described structure, the force for pressing the track member such as the inner ring in the axial direction can be adjusted as desired. Therefore, the operation of adjusting the preload applied to the double row rolling bearing device can be facilitated and the accuracy can be improved.

[0011]

1 and 2 show a first example of an embodiment of the present invention corresponding to claims 1 and 2. FIG. still,
The feature of this example lies in the preloading device of the double-row ball bearing device 1a, which is a type of double-row rolling bearing device. The structure of the double-row ball bearing device 1a itself is the same as that of the double-row ball bearing device 1 shown in FIGS. Will be omitted or simplified, and the following description will focus on features of the present invention. However, when implementing the present invention, only one inner ring raceway 5 of the pair of inner raceways 5 formed on the outer peripheral surface of the inner member is used as the inner raceway 6.
And the other inner raceway 5 can be formed directly on the outer peripheral surface of the shaft 2. In addition, the pair of outer raceways 7 can be formed directly on the inner peripheral surface of the outer cylinder 3. Furthermore, the present invention is not limited to the double row ball bearing apparatus, but may be implemented in a double row tapered roller bearing apparatus as long as it is a rolling bearing apparatus that applies a preload.

A hollow cylindrical shaft 2, which is an inner member constituting the double row ball bearing device 1a to be subjected to preload,
It is held by a holding tool 11a constituting a holding member.
The holding tool 11a is connected to and supported by the tip (the upper end in FIGS. 1 and 2) of the first rotating shaft 15 which also forms a holding member. The first rotating shaft 15 is rotatably supported by a first support member 16 via a first support bearing device 17. In the case of the present example, the first support bearing device 17 is configured by arranging a pair of ball bearings 18, each of an angular type, adjacent to each other in a back-to-back combination.

[0013] Such a first support bearing device 17 includes:
Inner rings 19, 19 constituting the pair of ball bearings 18, 18
Are externally fitted to the base half (the lower half in FIG. 1) of the first rotary shaft 15, and both inner rings 19, 19 are formed on the outer peripheral surface of the intermediate portion of the first rotary shaft 15. Step 23 and nut 23 screwed and tightened to the base end of the first rotary shaft 15
It is pinched without play between. In this case,
By sandwiching the inner rings 19 in this manner, the pair of ball bearings 18, 18 is brought into contact with the opposing axial end surfaces of the inner rings 19, 19 in contact with or close to each other. The dimensions of each part are regulated so that a desired preload is applied to each of the constituent balls 20, 20 (so that the rigidity of each of the ball bearings 18, 18 in the axial direction can be sufficiently ensured). Further, the outer races 21, 21 constituting the pair of ball bearings 18, 18 are fitted inside the first support member 16, and both outer races 21, 21 are located inside the intermediate portion of the first support member 16. The step portion 24 formed on the peripheral surface is held between the annular support member 25 fixed to the open end of the first support member 16 without play. In particular, in the case of the present example, the load capacity of the first support bearing device 17 is set to be 10 times or more the load capacity of the double row ball bearing device 1a to which the preload is to be applied.

Further, a belt groove 26 formed over the entire outer peripheral surface of the first rotary shaft 15 near the front end thereof, and a motor 27
The endless belt 29 is stretched between the outer peripheral surface of the drive pulley 28 which can be driven to rotate. Thus, the first rotating shaft 15 is rotatably driven by the motor 27.

On the other hand, the outer end face of one of the inner races 6 (upper in FIGS. 1 and 2) of the pair of inner races 6, each of which is a track member constituting an inner member, which is fitted to the shaft 2 outside. (Figure 1
Push arm 12 constituting the pressing member
a (a lower end surface in FIGS. 1 and 2). The push-in arm 12a is fixedly connected to the distal end (the lower end in FIGS. 1 and 2) of the second rotary shaft 30, which also constitutes a pressing member. The second rotary shaft 30 is rotatably supported by a second support member 31 as a fixed portion via a second support bearing device 32. In the case of this example, the second support bearing device 32 is similar to the first support bearing device 17 described above, and a pair of ball bearings 18, each of which is an angular type, is adjacent to each other in a back combination. It is composed by arranging. Then, similarly to the case of the first support bearing device 17, it is assembled between the second rotation shaft 30 and the second support member 31.

That is, the second support bearing device 32
Are inner rings 19, which constitute the pair of ball bearings 18, 18,
The outer ring 19 is externally fitted to the second rotating shaft 30, and the inner rings 19, 19 are connected to a stepped portion 33 formed near the tip of the second rotating shaft 30 and the base of the second rotating shaft 30. It is sandwiched between the end (the upper end in FIG. 1) and the nut 23 screwed and tightened without play. Then, by holding the two inner rings 19, 19 in this manner, these two inner rings 19, 19
In a state where the opposing axial end surfaces of the ball bearings 19 are in contact with or close to each other, a desired preload is applied to the balls 20, 20 constituting the pair of ball bearings 18, 18 (each of these balls). The dimensions of each part are regulated so that the rigidity of the ball bearings 18 in the axial direction can be sufficiently secured.
In addition, the outer ring 21 that forms the pair of ball bearings 18, 18,
21 is fitted in the second support member 31, and both outer rings 21, 21 are formed on the stepped portion 34 formed on the inner peripheral surface of the intermediate portion of the second support member 31 and the second support member 31.
Between the ring-shaped holding member 25 fixedly connected to the opening end of the opening. In particular, in the case of this example,
As in the case of the first support bearing device 17 described above, the load capacity of the second support bearing device 32 is set to be 10 times or more the load capacity of the double row ball bearing device 1a to which a preload is to be applied.

At the base end (upper end in FIG. 1) of the second support member 31, a fine movement feeder 35 is provided. The fine movement feeding device 35 is configured to include a device capable of generating a large force in the axial direction, such as a ball screw, for example. In the case of the present example, the outer end surface of the one inner ring 6 can be pressed by the pushing arm 12a based on the operation of the fine movement feeding device 35. The force of pressing the outer end surface of the inner ring 6 by the pushing arm 12a is applied to the base end of the first support member 16 (FIG. 1).
(Lower end of the sensor) can be measured freely by a load sensor 36 for measuring axial force.

Further, one end of a thread 13 constituting the loss torque measuring means is wound around the outer peripheral surface of the outer cylinder 3 which is an outer member constituting the double row ball bearing device 1a. Further, a load sensor 14 also constituting a loss torque measuring means is attached.

When applying the preload to the double row ball bearing device 1a by the preload applying device of the rolling bearing device of the present embodiment configured as described above, the first rotary shaft 15 is driven to rotate. , The shaft 2 and the inner rings 6, 6 are rotated at a predetermined speed, and the outer cylinder 3 which is to rotate with the shaft 2 is rotated.
And the rotational torque (loss torque) of the outer races 8 and 8 is measured by a load sensor 14 attached to the other end of the thread 13. Further, by pressing the outer end surface of the one inner ring 6 with the pushing arm 12a while measuring the loss torque in this manner, the one inner ring 6 is displaced toward the other inner ring 6. Then, when the loss torque substantially matches the preset value, the pushing arm 12a is stopped, and the displacement operation of the one inner ring 6 is completed.

As described above, it is conventionally known that there is a certain relationship between the loss torque and the magnitude of the preload of the double-row ball bearing device 1a as described above. Therefore, it has the same configuration as the double row ball bearing device 1a to which a predetermined preload should be applied,
In addition, the loss torque of the double-row ball bearing device to which an appropriate preload is applied {in general, 0.2 mN · m (2 gf · cm) or less is generally measured in advance in a small double-row ball bearing device 1a incorporated in an HDD or the like}. For example, in a state where the displacement operation of one inner ring 6 is completed as described above, an appropriate preload can be applied to each of the balls 10 and 10 constituting the double row ball bearing device 1a. As described above, the inner rings 6 and 6 are fixed to the shaft 2 by bonding or by tight fitting with sufficient fitting strength (strength that does not shift due to the reaction force of the preload). I do. When each of the inner rings 6, 6 is bonded and fixed to the shaft 2, the one inner ring 6 is continuously pressed by the pushing arm 12 with a load corresponding to the appropriate preload until the adhesive is solidified. .

In particular, in the case of the preloading device for a double row rolling bearing device according to the present embodiment, the load capacity of each of the first and second support bearing devices 17 and 32 is determined by changing the load capacity of the double row rolling bearing device to be preloaded. More than the load capacity of the ball bearing device 1a (10
More than twice). Therefore, when one inner ring 6 is pressed toward the other inner ring 6 as described above, the pressing force can be adjusted as desired. That is, the load capacity of each of the support bearing devices 17 and 32 is the double-row ball bearing device 1a.
If the load capacity is equal to or smaller than the above, when pressing one inner ring 6 toward the other inner ring 6 as described above,
There is a possibility that the above-described support bearing devices 17 and 32 are relatively large and elastically deformed. If such a problem occurs, the pressing force cannot be adjusted as desired. On the other hand, in the case of this example, the load capacity of each of the support bearing devices 17 and 32 is sufficiently (10 times or more) larger than the load capacity of the double row ball bearing device 1a. The above-described problem does not occur. Therefore, the pressing force can be adjusted as desired. As a result, the operation of adjusting the preload applied to the double row ball bearing device 1a can be facilitated and the accuracy can be improved.

Next, FIGS. 3 to 5 show a second embodiment of the present invention corresponding to claims 1 to 3. FIG. In the case of the present example, the holder 11 a for holding the shaft 2 is fixedly connected to the distal end of the output shaft 38 (holding member) of the direct motor 37. In the case of this example, the output shaft 38 is rotatably supported by a support bearing device (not shown) on a housing 39 which is a non-rotating support member, and the load capacity of the support bearing device is reduced by a load to be applied with a preload. It is sufficiently larger than the load capacity of the row ball bearing device 1a (for example, 1
0 times or more).

In the case of this embodiment, the double row ball bearing device 1a
The cylindrical dummy housing 40 constituting the loss torque measuring means is supported around the outer cylinder 3 constituting the outer cylinder 3 in a state in which rotation with respect to the outer cylinder 3 is prevented. For this reason, in the case of this example, the inner peripheral surface of the dummy housing 40 is formed into a conical concave surface, and the inner peripheral surface of the dummy housing 40 is formed at the end of the outer cylinder 3 (the upper end in FIGS. 3 and 4). On the outer surface,
It is frictionally engaged. Since the inner peripheral surface of the dummy housing 40 is a conical concave surface, the work of engaging and disengaging the inner peripheral surface and the outer peripheral surface at the end of the outer cylinder 3 is performed by the dummy housing 40.
This can be easily performed by applying a relative force in the axial direction between the outer cylinder 3 and the outer cylinder 3.

On the outer peripheral surface of the dummy housing 40, projecting pieces 41, 41 constituting a loss torque measuring means are fixed. The load sensor 14 constituting the loss torque measuring means is provided on the side surface of one of the protruding pieces 41 (the front surface in the rotation direction of the shaft 2 when the preload is applied).
Of the detecting section 42 is in contact with each other. This allows
At the time of applying a preload, the load sensor 14 can measure the loss torque of the outer cylinder 3 (the dummy housing 40) that is to rotate together with the shaft 2.

In the case of the present embodiment configured as described above, the shaft 2
Is directly connected to and fixed to the output shaft 38 constituting the direct motor 37, so that the preload applying device can be reduced in size. Further, the work of engaging and disengaging the dummy housing 40 with respect to the outer cylinder 3 can be easily performed. For this reason, when preloading is applied to a large number of double row ball bearing devices 1a, the efficiency of the preloading operation can be increased. Other configurations and operations are the same as those of the above-described first example.

[0026]

The preloading device for a double-row rolling bearing device according to the present invention is constructed and operates as described above, so that the axial force applied to the track member can be adjusted as desired. Therefore, the operation of adjusting the preload applied to the double row rolling bearing device can be facilitated and the accuracy can be improved. In addition, since the preload can be applied with high accuracy, when preloading is applied to a large number of double-row rolling bearing devices, variations in the preload applied to each of the double-row rolling bearing devices can be suppressed.

[Brief description of the drawings]

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

FIG. 2 is an enlarged cross-sectional view showing a double-row ball bearing device and a peripheral portion thereof.

FIG. 3 is a sectional view showing a second example of the embodiment of the present invention.

FIG. 4 is an enlarged cross-sectional view showing the double-row ball bearing device and its peripheral portion.

FIG. 5 is a view, viewed from above, of FIG. 4 with some parts omitted;

FIG. 6 is a half sectional view showing one example of a conventional structure.

FIG. 7 is a side view of FIG. 6;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1, 1a Double row ball bearing device 2 shaft 3 Outer cylinder 4 Ball bearing 5 Inner raceway 6 Inner raceway 7 Outer raceway 8 Outer raceway 9 Retainer 10 Ball 11, 11a Retainer 12, 12a Push arm 13 Thread 14 Load sensor 15 First Rotating shaft 16 First support member 17 First support bearing device 18 Ball bearing 19 Inner ring 20 Ball 21 Outer ring 22 Stepped portion 23 Nut 24 Stepped portion 25 Suppression member 26 Belt groove 27 Motor 28 Drive pulley 29 Endless belt 30 Second Rotary shaft 31 Second support member 32 Second support bearing device 33 Step portion 34 Step portion 35 Fine feed device 36 Load sensor for axial force measurement 37 Direct motor 38 Output shaft 39 Housing 40 Dummy housing 41 Projection piece 42 Detecting section

Claims (3)

[Claims] An inner member, a pair of inner raceways provided on the outer peripheral surface of the inner member at a distance from each other, and an outer member disposed concentrically with the inner member around the inner member.
A pair of outer raceways provided at positions facing the inner raceways on the inner peripheral surface of the outer member, and a plurality of rolling members provided rotatably between the outer raceways and the inner raceways, respectively. A double-row rolling bearing device comprising a moving body and a track member having an inner raceway formed on an outer peripheral surface thereof to form the inner member. In order to apply a desired preload to each of the rolling elements by displacing the track, while measuring the loss torque of the double-row rolling bearing device while rotating the inner member at a predetermined speed with respect to the outer member, When the member is displaced in the axial direction and the displacement work in the axial direction of the track member is completed in a state where the loss torque substantially matches a predetermined value set in advance, a method of applying a preload to the double row rolling bearing device is performed. A holding member that is rotatable while holding the inner member, a pressing member that is capable of axially pressing the track member in order to axially displace the track member, and is rotatable together with the track member; When the inner member is rotated at a predetermined speed by rotating one of the pressing member and the holding member, the loss torque is maintained while the outer member is kept substantially stationary. In a preloading device for a double row rolling bearing device provided with a loss torque measuring means capable of measuring the load torque, a load of the double row rolling bearing device is applied to a supporting member that does not rotate the holding member and the pressing member. A preload applying device for a double row rolling bearing device, wherein the device is rotatably supported by a support bearing device having a load capacity larger than the capacity. 2. The preloading device for a double-row rolling bearing device according to claim 1, wherein the load capacity of each support bearing device is 10 times or more the load capacity of the double-row rolling bearing device. 3. The preload application of a double row rolling bearing device according to claim 1, wherein one of the holding member and the pressing member is constituted by an output shaft of a motor. apparatus.