JPH11218131A - Bearing device with sliding member and holding member formed of porous sintered metal impregnated with lubricating oil, and equipment with the bearing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bearing device that can realize high accuracy and high reliability as well as miniaturization and thinning of OA equipment or acoustic image equipment. SOLUTION: A bearing device is provided with sliding members 11 formed of porous sintered metal and sliding with a rotary shaft, and a holding member 12 formed of porous sintered metal and holding the sliding members 11. The sliding members 11 and holding member 12 are formed of the same material, and the density of the sliding members 11 is larger than that of the holding member 12. Lubricating oil is therefore fed constantly from the holding member 12 to the sliding members 11 using a capillary phenomenon, and outflow of lubricating oil is suppressed to improve wear resistance and realize a long service life as well as miniaturization and thinning.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bearing device used for a motor mounted on, for example, an information storage device or an audio-visual device, and more particularly, to a device comprising a porous sintered metal impregnated with lubricating oil. The present invention relates to a bearing device having a sliding member and a holding member.

[0002]

2. Description of the Related Art In recent years, with the spread of computers, disk drive devices such as magnetic disk drive devices have been widely used as information storage devices. Especially,
2. Description of the Related Art Disk drives having a thickness of 2/3 inch or 1/2 inch have come to be mounted for a handy type A4 size computer which is easy to carry.

[0003] A spindle motor used in such a disk drive device has a small size and a small thickness.
In order to cope with the weight reduction, it is naturally required to reduce the size, thickness, and weight. The bearing device supporting the rotating shaft of the motor is required to have not only a small and thin structure but also a long life as well as rotational stability and wear resistance.

[0004] Conventionally, with respect to a bearing device for the purpose of stabilizing sliding of a rotating shaft and improving rotation stability,
Japanese Patent Application Laid-Open No. 7-243449 is known.

FIG. 5 shows a sectional view of a bearing device in the above-mentioned conventional example. In FIG. 5, the sliding member 1 has a cylindrical shape, and has a cylindrical shaft hole formed in the inner periphery for supporting a rotary shaft (not shown) inserted therein so as to be slidable in the circumferential direction. I have. With such a structure, the shaft is supported by the sliding member 1 so as to be rotatable. The sliding member 1 is press-fitted and fixed to the inner periphery of the holding member 2.

[0006] Here, the diameter of the shaft hole of the sliding member 1 is such that the intermediate portion 5 has one end 51 and the other end 53 in the axial direction.
2, the two ends 51 and 53
The part is a sliding part with the shaft. The outer periphery of the sliding member 1 has a portion 54 substantially corresponding to one end 51 of the shaft hole.
Is smaller than the outer diameters of the other parts.

The sliding member 1 is made of a sintered metal and is impregnated with a lubricating oil to constitute a so-called sintered oil-impregnated bearing.
In such a sintered oil-impregnated bearing, if the lubricating oil is not scattered and the operation is normal, the bearing life is usually determined mainly by the evaporation of the lubricating oil and the consumption due to the operation. And they are a function of temperature and time. Therefore, in such a sintered oil-impregnated bearing, the amount of impregnated lubricating oil is an important factor that is said to determine the bearing life,
In order to achieve a long life, it is necessary to impregnate the sintered metal with a predetermined amount of lubricating oil.

However, in the structure of the above-mentioned conventional bearing device, the sliding member 1 must be impregnated with a necessary amount of lubricating oil in order to secure the required life, but the allowable impregnation amount is limited. Therefore, it was necessary to secure a necessary amount of lubricating oil by increasing the volume of the sliding member 1. As a result, the overall shape of the bearing device has been increased.

[0009] Japanese Utility Model Publication No. 8-9450 discloses a conventional bearing device designed to prevent lubricating oil from scattering and extend the life of the bearing device.

FIG. 6 is a sectional view of a bearing device in the above-mentioned conventional example. 6, a sliding member 6 supporting a shaft 63 is shown.
A porous member 62 is disposed adjacent to one axial end surface. The porous member 62 prevents the lubricating oil from scattering in the axial direction from the gap between the shaft 63 and the sliding member 61.

However, although the structure of this bearing device is considered to be effective to some extent in preventing lubricating oil from scattering and continuing normal operation, the porous member 62 is disposed on the axial end surface of the sliding member 61. As a result, the bearing device as a whole becomes longer in the axial direction. Therefore, when there is a certain restriction on the axial length of the bearing device, it has been difficult to adopt it. If the sliding member 61 or the porous member 6 is
When the dimension in the axial direction is shortened, the shaft support length is shortened, which may adversely affect the whirling accuracy of the shaft and the life of the bearing.

[0012]

SUMMARY OF THE INVENTION The present invention maintains a necessary and sufficient amount of lubricating oil in spite of its small size and continuously supplies lubricating oil to a sliding portion between a rotating shaft and a sliding member. ,
An object of the present invention is to provide a bearing device that can achieve a long life.

[0013]

SUMMARY OF THE INVENTION The present invention provides a sliding member made of porous sintered metal and sliding on a rotating shaft, and a holding member made of porous sintered metal and holding the sliding member. A bearing device, comprising: a sintered metal having a density higher than that of the holding member; and a lubricating oil impregnated in both the sliding member and the holding member. A bearing device is provided.

Further, according to the present invention, the powder particle size of the sintered metal material of the sliding member is made smaller than the powder particle size of the sintered metal material of the holding member, and lubricating oil is applied to the sliding member and the holding member. A bearing device characterized by impregnation is provided.

With the above configuration, the bearing device can hold a necessary and sufficient amount of lubricating oil, always supply lubricating oil to a sliding member that slides on the rotating shaft, suppress outflow of lubricating oil, The wear property is improved, and a longer life can be realized. In addition, there is no influence on the volume and axial length of the sliding member as in the conventional example.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention is directed to a porous sintered metal sliding member that slides on a rotating body, and a porous sintered metal holding member that holds the sliding member. With
A bearing device wherein the density of the sintered metal of the sliding member is larger than the density of the sintered metal of the holding member, and the sliding member and the holding member are impregnated with lubricating oil. The lubricating oil is constantly supplied to the moving porous sliding member, the lubricating oil is prevented from flowing out, the service life is extended, and the wear resistance is improved.

According to a second aspect of the present invention, there is provided a porous sintered metal sliding member that slides on a rotating body, and a porous sintered metal holding member that holds the sliding member. A bearing device, wherein the sintered metal material of the sliding member is made of a material having a smaller powder particle diameter than the sintered metal material of the holding member, and the sliding member and the holding member are impregnated with lubricating oil, Lubricating oil is constantly supplied to the porous sliding member that slides with the rotating body, so that the lubricating oil is prevented from flowing out, the life is extended, and the wear resistance is improved.

According to a third aspect of the present invention, in the first or second aspect, the outer surface of the holding member further comprises:
This is a bearing device characterized by eliminating porosity by blinding or barrel processing, etc.
It has the effect of extending the life.

According to a fourth aspect of the present invention, in the first aspect of the present invention, the sliding member further comprises:
A bearing device comprising a plurality of bearing members, and has the same function as the first to third aspects mainly when a sliding member having a short axial length is combined.

According to a fifth aspect of the present invention, in the first aspect, the sliding member further comprises
This is a bearing device having a plurality of sliding portions, and has the same function as the first to third aspects in a sliding member of the type shown in the drawing of Japanese Patent Application Laid-Open No. 7-243449.

According to a sixth aspect of the present invention, in the bearing device according to any one of the first to third aspects, the holding member has a structure which can be directly fixed to a bracket or the like by caulking. In addition, since the holding member and the holding mechanism for holding the lubricating oil are integrally formed, the life can be further extended as compared with the first to third aspects, and the number of parts can be reduced.

According to a seventh aspect of the present invention, there is provided a bearing device according to the first or second aspect, wherein the sliding member and the holding member are made of the same kind of metal. It has the effect of preventing lubricating oil supply failure due to delicate differences in leakage and the like, which is likely to occur with a combination of metals, and achieves high reliability.

According to an eighth aspect of the present invention, in the bearing device according to the first aspect, the ratio of the density of the holding member to the sliding member is 1.0 or more and 1.05 or less. Yes, when manufactured in such a numerical range, it has excellent lubricating oil holding ability and supply ability, and has an effect of realizing high reliability.

According to a ninth aspect of the present invention, in addition to the first, second, or third aspect, the sliding member further includes a portion where the diameter of the shaft hole into which the rotating body is inserted is small and a portion where the diameter is larger. The sliding member along the inner circumference of the holding member.
A bearing device which is fixedly mounted to form a sliding portion between the rotary shaft and each of the small diameter portions of the shaft hole, always supplying lubricating oil from the holding member to the sliding member, The sliding portion can always be filled with the lubricating oil, the wear resistance is improved, and the service life can be extended.

According to a tenth aspect of the present invention, there is provided a bearing device according to any one of the first to thirteenth aspects, wherein a magnetic disk drive device, an optical disk drive device, a CD-ROM drive device, A spindle motor used in an MD drive device, a DVD drive device, or the like can achieve a long life.

According to an eleventh aspect of the present invention, a long life is achieved by using the bearing device according to any one of the first to thirteenth aspects for a bearing portion of a capstan shaft used in a tape recorder or the like. realizable.

[0027]

Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) FIG. 1 is a sectional view of a bearing device according to a first embodiment of the present invention. In FIG. 1, a sliding member 11 is made of porous sintered metal and has a cylindrical shape, and has a cylindrical shape on its inner periphery for supporting a rotating shaft (not shown) inserted therein so as to be slidable in the circumferential direction. Are formed. With this structure, the shaft is supported by the sliding member 11 so as to be rotatable. The sliding member 11 is press-fitted and fixed to the inner periphery of a holding member 12 also made of a porous sintered metal.

The sliding member will be further described. When two sliding members 11 each having a portion having a small diameter of the shaft hole and a portion slightly larger than the diameter are arranged in the axial direction, when viewed as a whole sliding member, The diameters of the shaft holes at one end and the other end are smaller than those at the middle. Both ends are sliding portions with the shaft. The sliding member 11 and the holding member 12 are previously impregnated with lubricating oil.

Here, by configuring the density of the sliding member 11 to be higher than the density of the holding member 12, the size of the porous hole is changed between the two, and the sliding member 11 is separated from the holding member 12 by utilizing the capillary phenomenon. Always supply lubricating oil to the sliding member 11,
The sliding portion can be always filled with the lubricating oil, the wear resistance is improved, and the life can be extended. The arrows shown in FIG. 1 indicate the flow of the lubricating oil.

Specifically, the sliding member 11 and the holding member 1
2 is the same kind of metal, for example, a copper-based oil-impregnated metal;
1 was 6.5 g / cm ³ , and the density of the holding member 12 was 6.
When the density is 37 g / cm ³ , suitable lubricating oil holding and supply is performed. When the density of the holding member 12 is reduced to 6.18 g / cm ³ or less, the pores become larger and the lubricating oil holding capacity may be reduced. I was assured. That is, the sliding member 11
If the ratio between the density of the oil and the holding member 12 is in the range of 1.0 or more and 1.05 or less, the holding ability and the supply ability of the lubricating oil are excellent, and high reliability can be realized.

Further, since the sliding member 11 and the holding member 12 are made of the same metal, it is possible to prevent a lubricating oil supply failure due to a delicate difference in properties such as wettability, which is likely to occur in a combination of different metals. High reliability can be realized.

In this embodiment, the number of the sliding members 11 is two, but may be one or three or more. By combining two or more sliding members 11 having a short axial length, two or more sliding parts are provided, and the same effect can be expected.

(Embodiment 2) FIG. 2 is a sectional view of a bearing device according to a second embodiment of the present invention. In FIG. 2, a sliding member 21 is made of a porous sintered metal and has a cylindrical shape, and has a cylindrical shape on its inner periphery for supporting a rotating shaft (not shown) inserted therein so as to be slidable in the circumferential direction. Are formed. With this structure, the shaft is supported by the sliding member 21 so as to be rotatable. The sliding member 21 is press-fitted and fixed to the inner periphery of a holding member 22 also made of a porous sintered metal. The sliding member is formed by arranging two short sliding members 21 in the axial direction, as in the first embodiment. The sliding member 21 and the holding member 22 are previously impregnated with lubricating oil.

Here, by making the powder particle size of the sliding member 21 smaller than the powder particle size of the holding member 22, the size of the porous hole between them is changed, and the capillary phenomenon is utilized. The lubricating oil is always supplied from the holding member 22 to the sliding member 21 so that the sliding portion can always be filled with the lubricating oil.
The wear resistance is improved, and a longer life can be realized. The arrows shown in FIG. 2 indicate the flow of the lubricating oil.

In the embodiment shown in FIG. 2, the number of the sliding members 21 is two, but may be one or three or more.

(Embodiment 3) FIG. 3 is a sectional view of a bearing device according to a third embodiment of the present invention. 3, in this embodiment, as in the first and second embodiments, the sliding member 31 is made of a porous sintered metal and has a cylindrical shape, and a rotating shaft (see FIG. (Not shown) is slidably supported in the circumferential direction. With this structure, the shaft is supported by the sliding member 31 so as to be rotatable.
The sliding member 31 is press-fitted and fixed to the inner periphery of a holding member 32 also made of porous sintered metal. The sliding member 31 and the holding member 32 are previously impregnated with lubricating oil.

In the present embodiment, the outer surface of the holding member 32 is closed or barreled to eliminate the porosity of the outer surface. Thereby, the prevention of the lubricating oil from flowing out from the outer surface of the holding member 32 is enhanced, and the service life can be further extended. The crosses shown in FIG. 3 indicate that the eyes are closed, and the arrows indicate that the lubricating oil is prevented from flowing out.

In the embodiment shown in FIG. 3, the number of the sliding members 31 is two, but may be one or three or more.

(Embodiment 4) FIG. 4 is a sectional view of a bearing device according to a fourth embodiment of the present invention. In this embodiment, as in the first, second, and third embodiments, the sliding member 41 is made of a porous sintered metal and has a cylindrical shape, and is inserted into the inner periphery thereof in FIG. A cylindrical shaft hole for supporting a rotating shaft (not shown) slidably in the circumferential direction is formed. With this structure, the shaft is supported by the sliding member 41 so as to be rotatable. The sliding member 41 is press-fitted and fixed to the inner periphery of a holding member 42 also made of a porous sintered metal. The sliding member 41 and the holding member 42 are impregnated with lubricating oil in advance.

In this embodiment, the holding member 42 is used.
Is directly fixed to the bracket 43 or the like by caulking, so that the sliding member 41, the holding member 42, the bracket 43 and the like are integrally formed, so that the length of the bearing device can be reduced without increasing the size of the bearing device. The advantageous effect that the life can be extended can be obtained. The arrow shown in FIG. 4 indicates that the holding member 42 is caulked and fixed to the bracket 43 or the like.

In the embodiment shown in FIG. 4, the number of the sliding members 41 is two, but the number of the sliding members may be one or three or more.

The spindle motor using the bearing device of the present invention is not limited to a magnetic disk drive device, an optical disk drive device, a CD-ROM drive device, an MD drive device, a DVD drive device and other disk drive devices and disk drive devices. It is also applicable to the above-mentioned device, and its industrial value is great.

Further, the bearing device of the present invention is not limited to application to a bearing portion of a motor. For example, in a tape recorder, a bearing portion of a capstan shaft that rotates by transmitting the torque of the motor through a belt or a gear. Needless to say, the present invention can be widely applied to bearings other than motors.

[0045]

As described above, according to the present invention, a sliding member made of porous sintered metal and sliding on a rotating shaft, and a holding member made of porous sintered metal and holding the sliding member are also provided. Constituting the bearing device with, the density of the sintered metal of the sliding member, larger than the density of the sintered metal of the holding member, or the powder particle size of the sintered metal material constituting the sliding member, Since the lubricating oil was impregnated into both the sliding member and the holding member while making the powder particle size smaller than the sintered metal material constituting the holding member, a sufficient amount of the lubricating oil was used even in a small bearing structure. The lubricating oil can be maintained, the lubricating oil is always supplied to the sliding member, the abrasion resistance is improved, and an excellent effect that a longer life can be realized is obtained.

Furthermore, if the outer surface of the holding member is closed or the barrel is processed to eliminate the porosity and the prevention of the lubricating oil from flowing out is enhanced, the service life can be further extended.

Furthermore, if the sliding member and the holding member are made of the same material, the lubricating oil supply failure due to a delicate difference in properties such as wettability, which is likely to occur in a combination of different metals, is prevented, and high reliability is achieved. Nature can be realized.

With the above effects, it is possible to provide a bearing device which is small in size, holds a necessary and sufficient amount of lubricating oil, continues to supply lubricating oil to the lubricating portion, and realizes a long life.

Although the present invention has been described in connection with the various embodiments described above, it is to be understood that various other modifications may be made.

The embodiments used in the specification and the drawings do not limit the present invention. Further, the details of the present embodiment do not limit the scope of the claims.

[Brief description of the drawings]

FIG. 1 is a sectional view of a bearing device according to a first embodiment of the present invention.

FIG. 2 is a sectional view of a bearing device according to a second embodiment of the present invention.

FIG. 3 is a sectional view of a bearing device according to a third embodiment of the present invention.

FIG. 4 is a sectional view of a bearing device according to a fourth embodiment of the present invention.

FIG. 5 is a sectional view of a bearing device in a conventional example.

FIG. 6 is a sectional view of another conventional bearing device.

[Explanation of symbols]

 11, 21, 31, 41 Sliding member 12, 22, 32, 42 Holding member 13 Bracket

Claims (11)

[Claims] 1. A sliding member made of porous sintered metal and sliding on a rotating shaft, and a holding member made of porous sintered metal for holding said sliding member, wherein said sliding member is sintered. A bearing device wherein the density of the metal is configured to be higher than that of the holding member, and both the sliding member and the holding member are impregnated with lubricating oil. 2. A sliding member made of porous sintered metal and sliding on a rotating shaft, and a holding member made of porous sintered metal and holding the sliding member, wherein the sliding member is sintered. A bearing device, wherein the metal material has a powder particle diameter smaller than that of the holding member, and both the sliding member and the holding member are impregnated with lubricating oil. 3. The bearing device according to claim 1, wherein a porosity of an outer surface of the holding member is eliminated. 4. The bearing device according to claim 1, wherein the number of sliding members is two or more. 5. The bearing device according to claim 1, wherein the sliding member has a sliding portion with the rotating shaft at two or more places. 6. The holding member according to claim 1, wherein the holding member has a structure which can be directly fixed to the bracket by caulking.
Or the bearing device according to 3. 7. The bearing device according to claim 1, wherein the material of the sliding member and the material of the holding member are the same kind of metal. 8. The ratio of the density of the sliding member to that of the holding member is 1.
The bearing device according to claim 1, wherein the value is greater than 0 and equal to or less than 1.05. 9. The sliding member has a portion where the diameter of the shaft hole into which the rotary shaft is inserted is small and a portion larger than the diameter, and two or more of the sliding members are fixed along the inner periphery of the holding member. 3. A sliding part is formed between the rotary shaft and each of the portions where the diameter of the shaft hole is small.
Or the bearing device according to 3. 10. The method according to claim 1, wherein
A spindle motor provided with the bearing device according to the above item. 11. The method according to claim 1, wherein
An apparatus provided with the bearing device according to the above item.