JP2003227514A - Swing arm device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thin, small swing arm device which stably supports an imbalanced load of the swing arm in a rocking motion, and improving the rigidity. <P>SOLUTION: A swing arm 10 provided with a magnetic head at one end thereof is disposed on a rotary support shaft 12 freely rotating normally or reversely through a bearing 1. The bearing 1 consists of a single row radial rolling bearing 6, and a thrust sliding bearing 5 comprising thrust plates 15 on both sides of an axial direction thereof. The width surface of an outer ring 3 in the radial rolling bearing 6 is a sliding bearing surface of the thrust sliding bearing 5. Two rows of spacer balls 7 are interposed in the axial direction 2 between respective rolling elements 4 adjoining to each other along the circumferential direction. The respective spacer balls 7 on both sides rotatably contact with the inner surface of the thrust plate 15 and the outer circumferential surface of an inner ring 2 respectively. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a swing arm device provided in a hard disk drive device or the like for supporting a magnetic head.

[0002]

2. Description of the Related Art With the miniaturization of computers, HDD devices (hard disk drive devices) built into computers have become thinner. This HDD device has
A spindle motor that rotates a magnetic disk that is an information storage medium as a rotational drive source, and a swing arm motor that swings a magnetic head that exchanges information (records and reads) with the hard disk to perform high-speed positioning on the hard disk. Is used. It has become necessary to shorten the axial length of any of the rotating body support mechanisms driven by these motors as the HDD device becomes thinner. Conventionally, these rotating body support mechanisms have a structure in which two ball bearings arranged in the axial direction are provided and an axial preload is applied to these bearings. A miniature bearing is used for each ball bearing. In recent years, special ball bearings smaller than the width dimension specified by JIS have been used in order to cope with thinning.

The swing arm device is a servo device for positioning a magnetic head on a hard disk at high speed. Therefore, the torque of the ball bearing, which is the fulcrum of the swing arm, is required to be as small as possible and to be stable. In addition, the natural frequency in the radial direction must be set high in order to ensure the stability of the servo system. In order to satisfy these requirements, when assembling two ball bearings, they are also assembled while measuring the natural frequency (rigidity).

[0004]

A conventional rotating body supporting mechanism for supporting a swing arm has two ball bearings as described above.
Since individual pieces are used, the cost is high and the axial length is long. In the future, as the HDD device will be made thinner, it is necessary to make the ball bearing thinner, and it is inevitable that manufacturing costs and assembly costs will increase.

As the bearing for the spindle motor,
Dynamic pressure fluid bearings have begun to be used in place of ball bearings, and assembly costs are being reduced. In the case of a spindle motor, since it rotates at a rotational speed of several thousand rpm, it is possible to replace the ball bearing with a hydrodynamic bearing. However, in the case of the swing arm, since the swing motion, that is, the forward and reverse rotation is performed, the velocity becomes zero at the swing end, and the fluid film is not formed. Therefore, the same hydrodynamic bearing as the spindle motor cannot be used.

In order to solve such a problem, the present applicant has tried a swing arm device shown in FIGS. 11 and 12 (Japanese Patent Application No. 2001-198974, etc.). This is because the bearing 101 that supports the swing arm on the rotation support shaft 12 is
It comprises a single row radial rolling bearing 6 and a thrust slide bearing 5. The width surface of the outer ring 3 of the radial rolling bearing 6 becomes the sliding bearing surface of the thrust sliding bearing 5. A cylindrical bearing housing 8 is fixed to the outer diameter surface of the outer ring 3 in a fitted state, and a swing arm is fixed to the outer circumference thereof. The thrust slide bearing 5 is composed of a pair of thrust plates 15 facing the width surfaces on both sides across the inner and outer races 2, 3. The thrust plate 15 is fixed to the width surface of the inner ring 2. The rolling elements 4 made of balls are held at a distance by a comb-shaped cage 9.

According to this structure, the radial rolling bearing 6
The radial load is supported by, and the moment load and thrust load are supported by the thrust slide bearing 5.
Therefore, the swing arm with an unbalanced load can be stably supported. Since the thrust sliding bearing 5 is such that the width surface of the outer ring 3 of the radial rolling bearing 6 serves as a sliding bearing surface, the entire combined bearing 101 has a simple and compact structure similar to a single row single rolling bearing. Becomes

However, in the swing arm device of the proposed example of the same figure, further miniaturization of future HDD devices,
Considering the thinning and the high-speed rotation, the bearing 101
Furthermore, further thinning and improvement in rigidity are required. For example, in the current HDD device having a disk diameter of 2.5 inches (63.5 mm), the thickness of the HDD device is 9 mm, the inner diameter of the bearing is 4 mm, the outer diameter is about 7 mm, and the ball diameter is 0.
It will be about 8 mm. Moreover, it is necessary to make the bearing 101 rigid for a control frequency of 2 kHz. In the future, it is considered that this disk diameter will be 1/2 or less of the above, and the bearing 101 will be further miniaturized. In such a very small bearing 101, it is extremely difficult to improve the rigidity.

For example, since the cage 9 is used, as shown in FIG.
As can be seen from 2, the distance between the rolling elements 4 becomes wider,
The rigidity cannot be improved by increasing the number of rolling elements. In particular, due to processing restrictions such as the thickness of the claw portion 9a that holds each rolling element 4 of the cage 9, a certain distance between the pockets of the cage 9 is required, and the number of rolling elements cannot be increased. The number of rolling elements can be increased by using the rolling element type in which rolling elements are packed, but in that case, adjacent balls will compete in opposite directions at their contact parts for rotation in the same direction. , The rotational torque increases. Some reduce the torque by inserting spacer balls that are slightly smaller than the rolling element diameter between the rolling elements.However, if such spacer balls are provided, the load will be reduced in the same way as when a cage is provided. It is not possible to increase the number of rolling elements that operate. In order to reduce the size of the bearing of the proposed example of FIG. 11, in the HDD device having the above dimensions, the inner ring 2 and the outer ring 3 have a wall thickness of about 0.35 mm. Since the wall thickness is thin and the rigidity is low as described above, it is difficult to secure accuracy by processing and assembling. The small and thin inner and outer races 2 and 3 are assembled by a method of adhering them to the shaft 12 and the housing 8. However, there is a problem that it takes time because of the large number of parts regardless of the extremely small swing arm device.

An object of the present invention is to provide a swing arm device which can stably support an unbalanced load of a swing arm that swings, can be made thin and compact, and can be improved in rigidity. It is to be. Another object of the present invention is to reduce the number of parts and improve assemblability.

[0011]

According to a first swing arm device of the present invention, a swing arm is rotatably mounted in a base through a bearing so that the swing arm can be rotated in the forward and reverse directions. Information of a magnetic disk is provided at one end of the swing arm. In the swing arm device provided with the magnetic head facing the recording surface and the head positioning mechanism for driving the swing arm in the forward and reverse directions, the above bearing has the following configuration. This bearing shall consist of a single row of radial rolling bearings and thrust sliding bearings. The thrust sliding bearing has a pair of thrust plates provided on both sides in the axial direction of the radial rolling bearing, and a sliding bearing surface formed on the width surface of the inner ring or the outer ring of the radial rolling bearing and contacting the thrust plate. Have. In the radial rolling bearing, the rolling elements are balls, and the spacer balls are interposed between the rolling elements adjacent in the circumferential direction in two rows in the axial direction. The spacer balls in both rows are respectively in rolling contact with the inner surface of the thrust plate in the corresponding axial direction and the outer peripheral surface of the inner ring or the inner peripheral surface of the outer ring.
According to this structure, the radial rolling bearing supports the radial load, and the thrust slide bearing supports the moment load and the thrust load. Therefore, the swing arm with an unbalanced load can be stably supported.
Thrust plain bearings have the width of the inner ring or outer ring of the radial rolling bearing as the plain bearing surface.
The entire bearing, which is a combination of both radial and thrust type bearings, has the same simple and compact structure as a single-row single rolling bearing. Therefore, a thin-walled type swing arm device is possible. Further, in the radial rolling bearing, since the spacer balls are interposed between the rolling elements in two rows in the axial direction, the interval between the rolling elements can be freely narrowed. That is, the two rows of spacer balls in the axial direction are located in the clearance space formed at the corner formed by the inner surface of the thrust plate and the peripheral surface of the inner ring or the outer ring between the rolling elements. By appropriately designing, the interval between the rolling elements can be arbitrarily narrowed. Therefore, the number of rolling elements can be increased and the radial rigidity can be improved. Since the rolling elements interpose the spacer balls, they do not directly contact each other, and an increase in torque is avoided. Further, since the spacer balls are provided in two rows in the axial direction, there are no restrictions on the top and bottom of the swing arm device.

In another swing arm device according to the present invention, the swing arm is rotatably mounted on a base through a bearing so that the swing arm can be rotated in the forward and reverse directions. One end of the swing arm faces the information recording surface of the magnetic disk. And a head positioning mechanism for driving the swing arm in the forward and reverse directions is provided in the swing arm device, wherein the bearing has the following configuration. The bearing is composed of a single row of radial rolling bearings and thrust sliding bearings. The thrust slide bearing has a pair of thrust plates provided on both sides in the axial direction of the radial rolling bearing, and a slide bearing surface formed on the width surface of the outer ring of the radial rolling bearing and in contact with the thrust plate. The inner ring and one thrust plate are formed as a part of the shaft, and the remaining one thrust plate is provided separately from the shaft and attached to the shaft. The outer ring is provided as part of a bearing housing to which the swing arm is attached. That is, the shaft has an inner ring side raceway surface of the radial rolling bearing, one thrust plate is provided in a flange shape, and the bearing housing has an outer ring side raceway surface of the radial rolling bearing. Therefore,
The components of the mechanism that supports the swing arm include a shaft, a housing, rolling elements, a rolling element spacing holding component, the remaining thrust plate, and a lubricant. According to this configuration,
Similar to the first swing arm device, the radial load is supported by the radial rolling bearing, and the moment load and the thrust load are supported by the thrust slide bearing.
Further, since the inner ring and outer ring of the radial rolling bearing and one thrust plate of the thrust slide bearing are integrated with the shaft and the bearing housing, not only the number of parts is reduced, but also the inner and outer rings are formed. The thickness of each component can be secured and the rigidity is improved. In addition, due to the increase in the thickness of the component parts, the processing accuracy is improved and the misalignment error during assembly is reduced. As the number of parts is reduced, the number of assembly steps is also reduced. As a result, the swing arm device can be made even thinner and smaller. For mounting a separate thrust plate to the shaft, for example, the tip side part of the part that becomes the inner ring of the shaft is made into a shaft part having a diameter smaller than that of the inner ring part through the step surface, and the small diameter is contacted with the step surface. It is attached by fitting a thrust plate to the shaft.

The swing arm device of the present invention may be a combination of the first and second swing arm devices. That is, in the second swing arm device, in the radial rolling bearing, the rolling elements are balls, and the spacer balls, which serve as a holding component for the rolling element intervals, are axially arranged between the rolling elements adjacent in the circumferential direction. The spacer balls of both rows may be interposed between the rows, and may be in rolling contact with the inner surface of the thrust plate and the outer peripheral surface of the inner ring, respectively, which correspond to each other. With this combination, the first
Also, the action and effect of the configuration of the second swing arm device can be provided together.

Of the swing arm devices having the above-described configurations according to the present invention, the one using the spacer balls as described above,
The spacer balls may be made of oil-containing resin. If the spacer balls are made of oil-impregnated resin, the supply amount of the lubricant is increased and the life of the bearing is improved. The diameter of the spacer balls is preferably less than 1/2 of the rolling element diameter. By setting the diameter of the spacer balls in this range, the distance between the rolling elements can be reduced, and the number of rolling elements arranged can be increased.

In the swing arm device of each of the above-mentioned configurations of the present invention, the inner race is provided with a raceway groove on which the rolling elements roll, and the axial center position of the inner raceway groove is set to the height of the magnetic head of the swing arm. It may be aligned with the center. By aligning the axial center position of the inner ring raceway groove of the radial rolling bearing with the center of the height of the magnetic head of the swing arm,
The center of the moment load applied to the bearing is the shaft center, and the moment load can be minimized.

Further, the pair of thrust plates may be members which also serve as seals for preventing leakage of the lubricant. By making the thrust plate also serve as a seal, it is possible to reduce the number of parts while achieving a lubricant leak prevention function, and reduce costs.
Further, it becomes possible to make the device even thinner.

[0017]

1 is a block diagram of a first embodiment of the present invention.
3 to FIG. In this swing arm device, the swing arm 10 is attached to a rotary support shaft 12 of a base 11,
The head positioning mechanism 22 is installed so as to be rotatable forward and backward through the bearing 1, and has a magnetic head 13 facing the information recording surface of the magnetic disk 14 at one end of the swing arm 10 to drive the swing arm 10 forward and backward. Is provided.
The magnetic head 13 is for recording or reading information, or for both recording and reading.

The base 11 comprises a housing of a hard disk drive device and the like. The rotary support shaft 12 is a hollow shaft having an internal thread formed on the inner diameter surface thereof, and is fixed to the base 11 by a set screw 23 inserted from the rear surface of the base 11. The head positioning mechanism 22 is an oscillating motor including a rotor 22a provided on the other end of the swing arm 10 and a stator 22b installed on the base 11 so as to face the rotor 22a. In this example, the rotor 22a is a coil and the stator 22b is a magnet. Conversely, the rotor 22a may be a magnet and the stator 22b may be a coil.

As shown in FIG. 3, the bearing 1 comprises a single row radial rolling bearing 6 and a thrust slide bearing 5 having a pair of thrust plates 15 provided on both sides of the radial rolling bearing 6 in the axial direction. . The rolling elements 4 are balls.
A cylindrical bearing housing 8 is fixed to the outer diameter surface of the outer ring 3 in a fitted state. The raceway surface 2a of the inner ring 2 and the raceway surface 3a of the outer ring 3 of the radial rolling bearing 6 are cylindrical surfaces. Raceways 2a, 3 of these inner and outer rings 2, 3
a is superfinished. These orbital surfaces 2a, 3
The radial gap between a and the rolling element 4 is a negative gap,
This improves the radial rigidity. One of the raceways 2a, 3a of the inner ring 2 and the outer ring 3, for example, the inner ring 2
The raceway surface 2a may be formed by providing a raceway groove instead of a cylindrical surface and by the inner surface of the groove. The raceway grooves forming the raceway surfaces 2a and 3a are preferably grooves having an arcuate cross-sectional shape having a radius of curvature slightly larger than that of the rolling elements 4.

Each rolling element 4 in the radial rolling bearing 6
The spacer balls 7 keep a distance between them in the circumferential direction. The spacer balls 7 are arranged in two rows in the axial direction between the rolling elements 4 adjacent to each other in the circumferential direction. The spacer balls 7 in both rows are arranged closer to the inner ring 2 than the rolling element 4. These spacer balls 7 are in rolling contact with the inner surface of the thrust plate 15 and the outer peripheral surface of the inner ring 2 in the corresponding axial direction. The diameter of the spacer balls 7 is less than 1/2 of the diameter of the rolling elements 4. The spacer balls 7 are made of steel balls or resin. When it is made resinous, it may be made of an oil-containing resin. Examples of the oil-containing resin include polyloop (NT
Company N: trade name) can be used.

The thrust slide bearing 5 comprises a pair of thrust plates 15 and a slide bearing surface formed on the width surface of the outer ring 3 of the radial rolling bearing 6 and contacting the thrust plate 15. The thrust plate 15 is fixed to the width surface of the inner ring 2. The width of the inner ring 2 should be slightly wider than the width of the outer ring 3,
For example, the thrust plate 15 and the outer ring 3 are made wider by about several microns.
A gap G is provided between and. The size of the gap G is large enough not to cause interference between the rotor 22a and the stator 22b of the head positioning mechanism 22 (FIG. 1) even if the inner ring 2 and the outer ring 3 relatively move in the axial direction by the gap G. To be taken. The facing surface between the width surface of the outer ring 3 and the thrust plate 15 forming the gap G serves as a plain bearing surface. The thrust slide bearing 5 is required to have wear resistance. In order to respond to this, it is necessary to improve the finish roughness of the slide bearing surface of the thrust plate 15, increase the hardness of the surface, or use a high hardness material for the thrust plate 15. Has been taken. Nitrogen treatment, shot blasting, hard coating (DLC, T
IN, etc.) can be adopted. As the high hardness material, ceramics can be adopted in addition to the bearing steel.

The thrust plate 15 constituting the thrust slide bearing 5 also serves as a seal for preventing leakage of the enclosed lubricant. Specifically, the gap G2 between the outer diameter surface of the thrust plate 15 and the inner diameter surface of the fixing member 8 is set so that the lubricant does not move to the outside of the bearing due to a capillary phenomenon depending on the viscosity of the lubricant. There is.

As shown in FIG. 2, the rotation support shaft 12 of the bearing 1
The inner ring 2 is fitted to the outer diameter surface of the rotary support shaft 12 to be fixed to. The inner ring 2 is fixed by using this fitting as an interference fit or by adhering. Swing arm 1 to bearing 1
For fixing 0, the bearing housing 8 on the outer periphery of the outer ring 3 is fitted into the fitting hole 10a provided in the middle portion of the swing arm 10 in the longitudinal direction, and the male screw portion provided on the outer diameter surface of the bearing housing 8. It is performed by screwing a nut 24 (not shown) and tightening it.

According to this structure, the bearing 1 can receive the load in the radial direction by the single-row radial rolling bearing 6 and the moment load and the thrust load by the thrust slide bearing 5. Therefore, the unbalanced load of the swing arm 10 that swings can be supported by the single bearing 1. Therefore, the swing arm device can be thinned. Further, since the bearing 1 is preloaded only in the radial direction, smooth rotation is possible while maintaining high rigidity. The required rigidity can be obtained by controlling the amount of preload (negative clearance amount) in the radial direction.

Further, the radial rolling bearing 6 is composed of the rolling elements 4
Since the spacer balls 7 are interposed between the two rows in the axial direction,
The space between the rolling elements 4 can be freely narrowed. That is, the two rows of spacer balls 7 in the axial direction are located in the gap spaces formed at the corners formed by the inner surface of the thrust plate 15 and the peripheral surface of the inner ring 2 between the rolling elements 4, so that the spacer balls 7 By appropriately designing the ball diameter, the interval between the rolling elements can be arbitrarily narrowed. Therefore, the number of rolling elements 4 arranged can be increased, and the radial rigidity can be improved. Since the rolling elements 4 have the spacer balls 7 interposed therebetween, they do not come into direct contact with each other, and an increase in torque is avoided. Further, since the spacer balls 7 are provided in two rows in the axial direction, there are no restrictions on the top and bottom of the swing arm device. When the spacer balls 7 are made of an oil-containing resin, the amount of lubricant supplied is increased and the life is extended.

Explaining the number of rolling elements by taking an example of dimensions,
A bearing with an inner diameter of 4 mm, an outer diameter of 7 mm, and a rolling element diameter of 0.8 mm is a typical conventional bearing used in a 2.5-inch (63.5 mm) HDD device. Due to processing restrictions such as the thickness of the claws, the number of rolling elements is 12 or less. On the other hand, when the spacer balls 7 are used, the number of rolling elements is equal to the pitch circle diameter PCD of the rolling element arrangement.
A value close to × π / roller diameter can be taken. When the bearing 1 of the embodiment of FIG. 3 has the above-mentioned inner and outer diameters and PCD is the average of the inner and outer diameters, the maximum number of rolling elements is 21. This is a large increase compared to the conventional 12 pieces, and the effect of improving the radial rigidity is great.

Further, in the bearing 1, the thrust plate 15 constituting the thrust slide bearing 5 provides the function of preventing leakage of the enclosed lubricant. A lubricant is enclosed in the bearing 1 of this type for the purpose of reducing the torque. However, if the lubricant goes out of the bearing, it contaminates the environment inside the hard disk drive device, so that a seal is required. Conventionally, the seal plate was press-fitted into the rolling bearing, but in this embodiment, since the thrust plate 15 is also used as the seal member, the conventional seal plate can be omitted, the number of parts can be reduced, and the cost can be further reduced. Further thinning becomes possible.

In the above embodiment, the spacer balls 7 are arranged on the inner ring 2 side, but the spacer balls 7 may be arranged on the outer ring 3 side rather than the rolling elements 4. In the above embodiment, the thrust plate 15 of the thrust slide bearing is attached to the end surface of the inner ring 2.
However, the width of the outer ring 3 is made wider than the width of the inner ring 2 and the thrust plate 15 is provided on the end surface of the outer ring 3 between the inner ring 2 and the thrust plate 15. You may comprise a plain bearing surface. In this case, the spacer balls 7 may be arranged on the inner ring 2 side or the outer ring 3 side of the rolling elements 4.

In each of the above embodiments, the thrust plate 15
It is preferable that the plain bearing surface is subjected to lubricity improving treatment, and the improvement of lubricity can contribute to the improvement of wear resistance. As the lubricity improving process, as shown in FIG.
5. Making the sliding bearing surface of No. 5 a surface having innumerable recesses 16 and providing a groove 17 on the sliding bearing surface of the thrust plate 15 as shown in FIG. Is effective.

7 to 9 show another embodiment of the present invention. This embodiment is the same as the first embodiment.
The bearing 1 including the shaft 12 and the bearing housing 8 is changed as follows.
Is the same as the embodiment of. In this swing arm device, the bearing 1A includes a single-row radial rolling bearing 6 and a thrust slide bearing 5 having a pair of thrust plates 15 and 15A provided on both sides of the radial rolling bearing 6 in the axial direction. The rolling elements 4 are balls. The raceway surface 2a of the inner ring 2 in the radial rolling bearing 6 is formed by the inner surface of the raceway groove, and the raceway surface 3a of the outer ring 3 is a cylindrical surface. The raceways 2a, 3a of the inner and outer rings 2, 3 are superfinished. These raceways 2a and 3a and rolling elements 4
The radial gap between and is a negative gap. Each rolling element 4 of the radial rolling bearing 6 is held by a cage 9. The retainer 9 has, for example, a comb shape.

The thrust slide bearing 5 comprises a pair of thrust plates 15 and 15A, and a slide bearing surface formed on the width surface of the outer ring 3 of the radial rolling bearing 6 and contacting the thrust plates 15 and 15A. The inner ring 2 and one thrust plate 15A are formed as a part of the shaft 12A, and the remaining one thrust plate 15 is provided separately from the shaft 12A and attached to the shaft 12A. The outer ring 3 is provided as a part of the bearing housing 8A to which the swing arm 10 is attached. That is, the shaft 12A has the inner ring side raceway surface 2a of the radial rolling bearing 6 and is provided with one thrust plate 15A in a flange shape. The bearing housing 8A has the outer race side raceway surface 3a of the radial rolling bearing 6. Therefore, the components of the mechanism that supports the swing arm 10 are the shaft 12
A, bearing housing 8A, rolling element 4, cage 9, remaining thrust plate 15 and lubricant.

The shaft 12A has a shaft portion 12Aa having a diameter smaller than that of the portion of the inner ring 2 via a step surface 12Ab at a portion closer to the tip than the portion which becomes the inner ring 2, and is in contact with the step surface 12Ab to form a small diameter shaft portion 12Aa. The thrust plate 15 is attached to the shaft 12 </ b> A by fitting the center hole of the thrust plate 15 into the fitting. Instead of providing the shaft 12A with the small-diameter shaft portion 12Aa, the thrust plate 15 may be attached in a state of contacting the end face of the shaft 12A. Bearing In the bearing housing 8A, a portion to be the outer ring 3 projects annularly on the inner periphery of the cylindrical portion 8Aa, and both ends of the cylindrical portion 8Aa have thrust plates 15, 1
It extends axially outward from the outer surface of 5A. Bearing The bearing housing 8A has a flange 8Ab at one end and a male screw portion 8Ac at the other end on the outer periphery of the cylindrical portion 8Aa. The swing arm 10 has this flange 8A.
It is clamped and fixed between b and the nut 24 screwed to the male screw portion 8Ac. Further, the thrust plates 15 and 15A are
As shown in FIG. 9, the chamfer 15 is attached to the outer peripheral edge on the outer surface side.
You may provide a. As a result, it is possible to obtain the action of preventing the leakage of the enclosed lubricant by utilizing the surface tension of the lubricant. The structure and effect of providing this chamfer 15a are
It can be applied to any of the embodiments of the present invention.

As in the first embodiment, the width of the portion to be the inner ring 2, that is, the distance between the thrust plates 15 and 15A is made slightly wider than the width of the outer ring 3, for example, about several microns, and the thrust is increased. A gap G is provided between the plates 15 and 15A and the outer ring 3. The size of this gap G is
Even if the inner ring 2 and the outer ring 3 move relative to each other in the axial direction,
The size is such that the rotor 22a and the stator 22b of the head positioning mechanism 22 (FIG. 1) do not interfere with each other.
The width surface of the outer ring 3 forming the gap G and the thrust plate 15,
The surface facing 15A serves as a plain bearing surface.

In this structure, similarly to the swing arm device of the first embodiment, the radial load is supported by the radial rolling bearing 6, and the moment load and the thrust load are supported by the thrust slide bearing 5. Also, the inner ring 2 of the radial rolling bearing 6 and the thrust plate 1 on one side
Since 5A is integrated with the shaft 12 and the outer ring 3 is integrated with the bearing housing 12, not only the number of parts is reduced, but also the thickness of the components such as the inner and outer rings 2, 3 is secured. The rigidity is improved. Also, the increased wall thickness improves the processing accuracy and reduces misalignment errors during assembly. Further, the reduction of the number of parts also reduces the number of assembling steps. As a result, the swing arm device can be made even thinner and smaller.

Also in this embodiment, the thrust plate 1
The sliding bearing surfaces of 5 and 15 A are preferably subjected to lubricity improving treatment, and the improvement of lubricity can contribute to the improvement of wear resistance. As the lubricity improving process, the configuration described above with reference to FIGS. 5 and 6 can be adopted. In addition, in FIGS.
The raceway surface 2a of the outer ring 3 as the inner surface of the raceway groove.
Although an example in which no groove is attached is shown, both raceway surfaces 2a, 3
A may be formed on the inner surface of the raceway groove, or the outer race 3 may be provided with a raceway groove and the inner race 2 may be formed without a groove.

FIG. 10 shows still another embodiment of the present invention. This swing arm device is a combination of the first embodiment and the embodiments of FIGS. 7 to 9. That is, in this embodiment, in the swing arm device of the embodiment shown in FIGS. 7 to 9, instead of providing the retainer 9, a spacer serving as a holding component for the rolling element space between the rolling elements 4 adjacent to each other in the circumferential direction. The balls 7 are arranged in two rows in the axial direction. The spacer balls 7 in both rows roll on the inner surfaces of the corresponding axial thrust plates 15 and 15A and the outer peripheral surface of the inner ring 2, respectively. With this combination, the actions and effects of the configurations of the swing arm devices of the above-described embodiments can be obtained together.

In the swing arm device of each of the above embodiments, when the raceway surface 2a of the inner ring 2 is formed by a raceway groove, the axial center position of the raceway groove of the inner ring is determined by the magnetic head 13 of the swing arm 10. It may be combined with the center of height. By aligning the axial center position of the inner ring raceway groove of the radial rolling bearing 6 with the height center of the magnetic head 13 of the swing arm 10, the center of the moment load applied to the bearings 1 and 1A becomes the shaft center, and the moment load is reduced. Can be minimized. When the center of the magnetic head 13 in the height direction deviates from the center of gravity position, the center position of the inner ring raceway groove in the axial direction may be aligned with the center of gravity position.

[0038]

According to the first swing arm device of the present invention, the bearing supporting the swing arm comprises a single row radial rolling bearing and a thrust sliding bearing, and the thrust sliding bearing is a shaft of the radial rolling bearing. A pair of thrust plates provided on both sides in the direction, and a sliding bearing surface formed on the width surface of the inner ring or outer ring of the radial rolling bearing and in contact with the thrust plate, wherein the radial rolling bearing has rolling elements. Spacer balls are arranged in two rows in the axial direction between rolling elements adjacent to each other in the circumferential direction. The spacer balls in both rows are the inner surface of the corresponding thrust plate in the axial direction and the outer peripheral surface of the inner ring. Alternatively, since it comes into rolling contact with each of the inner peripheral surface of the outer ring, it is possible to stably support the unbalanced load of the swinging arm that swings, and it is possible to reduce the thickness and size. In, and it is possible to improve the rigidity. A second swing arm device of the present invention is
The bearing that supports the swing arm is composed of a single row radial rolling bearing and a thrust sliding bearing, and the thrust sliding bearing includes a pair of thrust plates provided on both sides in the axial direction of the radial rolling bearing and the radial rolling bearing. A bearing surface formed on the width surface of the outer ring of the bearing and in contact with the thrust plate, the inner ring and one thrust plate are formed as a part of the shaft, and the remaining one thrust plate is the shaft and Since the outer ring is provided separately and attached to the shaft, and the outer ring is provided as a part of the bearing housing to which the swing arm is attached, it is possible to support an unbalanced load of the swing arm that swings. Can be stably performed, thinning and miniaturization are possible, and rigidity can be improved. When the spacer balls are made of an oil-containing resin, the lubricant supply amount is increased and the bearing life is improved. Set the diameter of the spacer ball to 1 of the rolling element diameter.
If it is less than / 2, it is possible to increase the number of rolling elements. If the inner race is provided with a raceway groove on which the rolling elements roll and the axial center position of the raceway groove of this inner race is aligned with the height center of the magnetic head of the swing arm, the moment resistance performance is improved and the swinging motion is improved. The unbalanced load of the moving swing arm can be supported more stably. When the pair of thrust plates are members that also serve as seals that prevent the leakage of the lubricant, the number of parts can be reduced, the cost can be reduced, and the thickness can be further reduced.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a swing arm device according to a first embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view of a rotation supporting portion of the swing arm device.

FIG. 3 is a sectional view of a bearing of the swing arm device.

FIG. 4 is a cutaway plan view of the bearing.

FIG. 5 is a plan view showing an example of a thrust plate in the bearing.

FIG. 6 is a plan view showing another example of the thrust plate in the bearing.

FIG. 7 is a sectional view of a swing arm device according to still another embodiment of the present invention.

FIG. 8 is an enlarged cross-sectional view of a rotation supporting portion of the swing arm device.

FIG. 9 is a cross-sectional view of a bearing of the swing arm device.

FIG. 10 is a sectional view of a bearing according to still another embodiment of the present invention.

FIG. 11 is a sectional view of a proposed example of a swing arm device.

FIG. 12 is a cutaway plan view of a bearing in the swing arm device.

[Explanation of symbols]

1,1A ... Bearing 2 ... Inner ring 2a ... orbital plane 3 ... Outer ring 3a ... orbital plane 4 ... rolling elements 5 ... Thrust plain bearing 6 ... Radial rolling bearing 8, 8A ... Bearing Bearing housing 10 ... Swing arm 12, 12A ... Rotating spindle 13 ... Magnetic head 14 ... Magnetic disk 15,15A ... Thrust plate 22 ... Head positioning mechanism

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Claims (7)

[Claims] 1. A swing arm is rotatably and reversely installed on a base via a bearing, and a magnetic head facing an information recording surface of a magnetic disk is provided at one end of the swing arm.
In a swing arm device provided with a head positioning mechanism for driving the swing arm in the forward and reverse directions, the bearing comprises a single row radial rolling bearing and a thrust slide bearing,
The thrust sliding bearing has a pair of thrust plates provided on both sides in the axial direction of the radial rolling bearing, and a sliding bearing surface formed on the width surface of the inner ring or the outer ring of the radial rolling bearing and contacting the thrust plate. In the above radial rolling bearing, the rolling elements are balls, and the spacer balls are interposed in two rows in the axial direction between the rolling elements adjacent in the circumferential direction, and the spacer balls in both rows are in the corresponding axial direction. The swing arm device, wherein the inner surface of the thrust plate and the outer peripheral surface of the inner ring or the inner peripheral surface of the outer ring are in rolling contact with each other. 2. A swing arm is rotatably and reversely installed on a base through a bearing, and a magnetic head facing an information recording surface of a magnetic disk is provided at one end of the swing arm.
In a swing arm device provided with a head positioning mechanism for driving the swing arm in the forward and reverse directions, the bearing comprises a single row radial rolling bearing and a thrust slide bearing,
The thrust slide bearing has a pair of thrust plates provided on both sides in the axial direction of the radial rolling bearing, and a slide bearing surface formed on the width surface of the outer ring of the radial rolling bearing and in contact with the thrust plate. The inner ring and one thrust plate are formed as a part of a shaft, the remaining one thrust plate is provided separately from the shaft and attached to the shaft, and the outer ring is the swing arm. A swing arm device, wherein the swing arm device is provided as a part of a bearing housing for mounting. 3. In the radial rolling bearing, rolling elements are balls, and spacer balls serving as holding members for the rolling element intervals are interposed in two rows in the axial direction between rolling elements adjacent in the circumferential direction, 3. The swing arm device according to claim 2, wherein each of the spacer balls in both rows is in rolling contact with the inner surface of the corresponding thrust plate in the axial direction and the outer peripheral surface of the inner ring. 4. The swing arm device according to claim 1, wherein the spacer balls are made of an oil-containing resin. 5. The swing arm device according to claim 1, 3 or 4, wherein a diameter of the spacer ball is less than ½ of a rolling element diameter. 6. An inner ring is provided with a raceway groove on which a rolling element rolls, and the axial center position of the inner raceway groove is aligned with the center of the height of the magnetic head of the swing arm. The swing arm device according to any one of 5 above. 7. The swing arm device according to claim 1, wherein the pair of thrust plates are members that also serve as seals that prevent leakage of the lubricant.