JP3879906B2 - Sintered oil-impregnated bearing, its hydraulic holding structure in the hole, and method for manufacturing sintered oil-impregnated bearing - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a sintered oil-impregnated bearing, a hydraulic pressure retaining structure in the hole, and a method for manufacturing a sintered oil-impregnated bearing.
[0002]
[Prior art]
Utilizing the porosity of a sintered body obtained by sintering metal powder, a sintered oil-impregnated bearing (hereinafter, referred to as “self-lubricated”) that is impregnated with 10-30% oil (lubricant) by volume ratio. "Bearing" or "Bearing body" is an excellent feature that normal bearings can be burned immediately if they run out of oil, but can be operated without seizure even if they are already smoked. have.
[0003]
The reason why the sintered oil-impregnated bearing has such characteristics is based on the fact that the bearing has innumerable voids. The principle of operation of a general sintered oil-impregnated bearing will be described with reference to FIG. When the shaft body 2 rotates in the direction indicated by the arrow R in the bearing 1, the lubricating oil contained in the pores of the porous bearing 1 is sucked out in the same manner as the suction action of the pump. It oozes out at the interface with the sliding receiving surface 3. The lubricating oil 4 that has oozed out is drawn in the shape of a wedge in the direction indicated by the arrow R by the rotational force of the shaft body 2 to form an oil film and exerts a lubricating effect. Under pressure, it is pushed back into the hole of the bearing 1 again. By repeating such an operation continuously, the lubricating oil 4 circulates inside the bearing 1.
[0004]
The greatest advantage of the bearing 1 having such a circulating function of lubricating oil is that it can be used without lubrication. Not only automobiles and civil engineering machines, but also household equipment, office machines, etc. have sufficient lubrication in terms of environment or mechanism. It is widely used in places where it cannot be desired, and in recent years, it has been actively used as a motor bearing provided in a disk drive of OA equipment, acoustic equipment, etc. for end users and as a small fan motor bearing.
[0005]
[Problems to be solved by the invention]
By the way, the bearings having the above-mentioned excellent advantages are not necessarily universal, and there is still room for improvement. One of them is a problem that the amount of the lubricating oil drawn in is reduced due to the rotation of the shaft.
[0006]
When the sintered oil-impregnated bearing is used in an automobile, a civil engineering machine, etc., the shaft body 2 supported by the bearing 1 is normally used in a state where a load is applied in a certain direction (for example, the F direction shown in FIG. 5). The bearing 1 and the shaft body 2 are always pivotally supported in a state where they are closest to each other at a fixed point (for example, the point t1 shown in FIG. 5). However, when used as a bearing for a fan motor or a disk drive motor, the weight balance of a disk such as a music CD or DVD, a fan, etc. is unbalanced, and the shaft is directly connected to such an eccentric disk. When the body is rotated at a high speed by the drive motor, when viewed from the longitudinal section direction of the shaft body, the rotation of the shaft body 2 of the drive motor is relative to the ideal axis P1 of the shaft body 2 as shown in FIG. The shafts P2 and P3 are inclined so as to be inclined with respect to the inner diameter surface of the bearing 1 and rotated. Further, when viewed from the cross-sectional direction of the shaft body, as shown in FIG. 7, the shaft body 2 is moved so that the shaft center of the shaft body 2 moves from the shaft centers P11 to P12 and P13 along the inner periphery of the bearing 1. Rotating in the M direction, the bearing 1 and the shaft body 2 always move while being closest to each other at different points (for example, various points such as t11, t12, and t13 shown in FIG. 7). Such slewing rotation is a phenomenon generally seen in cantilever bearings. However, when this happens, the effect of drawing the lubricating oil 4 that has oozed out into the interface between the bearing 1 and the shaft body 2 in a wedge shape is reduced, and the amount of pull-in is reduced. On the other hand, since the ratio of the pushing amount of the lubricating oil 4 pushed into the bearing 1 is increased, an appropriate balance cannot be achieved and the lubricating oil pressure at the interface is lowered.
[0007]
To solve the above-described problem of lowering the lubricating oil pressure, it is conceivable that the viscosity of the lubricating oil 4 is increased to make it difficult to push the lubricating oil 4 into the bearing 1 (to make it difficult to return). However, in order to stabilize the reading accuracy of the optical pickup for a disk drive such as a CD, and to reduce the vibration noise of a fan motor, the clearance between the shaft body 2 and the sliding receiving surface 3 of the bearing 1 is reduced. On the contrary, it is desired to lower the viscosity of the lubricating oil 4.
[0008]
Accordingly, an object of the present invention is to provide a sintered oil-impregnated bearing capable of suppressing a decrease in lubricating oil pressure, an in-hole hydraulic pressure retaining structure, and a manufacturing method thereof.
[0009]
[Means for Solving the Problems]
  That is, the present invention has a cylindrical slide receiving surface that rotatably supports a shaft body, and surface layer voids that are exposed on a part or all of the outer surface of the bearing body excluding the slide receiving surface. The sintered oil-impregnated bearing that is packed is a secondary sintered body of a bearing body made of a primary sintered body and a metal powder that is pressure-bonded to the surface layer holes of the bearing body.TheIn the surface vacanciesPacked with a thickness of 0.005 to 0.015 mmA sintered oil-impregnated bearing is provided.
[0010]
According to this sintered oil-impregnated bearing, a part or all of the outer surface of the bearing body excluding the sliding receiving surface is formed as a clogging surface clogging the surface layer holes. Therefore, even if the lubricating oil in the pores of the sintered oil-impregnated bearing tries to escape from the surface other than the sliding bearing surface to the outside of the sintered oil-impregnated bearing, the surface layer pores that become the escape path are clogged, and the leakage to the outside Can be reduced. Therefore, it is possible to maintain high lubricating oil pressure on the sliding bearing surface, and it is possible to maintain smooth rotation of the shaft body over a long period of time.
[0011]
Since the lubricating oil pressure on the sliding bearing surface can be kept high as described above, an appropriate lubricating oil pressure on the sliding bearing surface can be exerted even when the shaft body rotates by sliding, and the sliding movement between the shaft body and the bearing is possible. There is no need to increase the clearance between the receiving surface and the viscosity of the lubricating oil.
[0012]
  In addition, according to this sintered oil-impregnated bearing, by adopting sintering as a fixing method, a predetermined bearing surface can be reliably clogged, and air holes opened on the bearing surface as a clogging surface can be formed. Since it is possible to clog, it is possible to provide a sintered oil-impregnated bearing that can maintain a high oil pressure on the sliding receiving surface and maintain a preferable lubrication state.
[0013]
  The present invention can be a sintered oil-impregnated bearing in which the metal powder is a bronze alloy powder, and the bearing body can be a sintered oil-impregnated bearing made of a mixed powder of bronze alloy and iron-copper alloy. it can.
[0014]
  The present invention also provides a sintered oil-impregnated bearing in which an adjacent surface continuous with the sliding receiving surface of the outer surface of the bearing body is formed as a clogging surface.
[0015]
  According to this sintered oil-impregnated bearing, the adjacent surface that is continuous with the sliding bearing surface of the sintered oil-impregnated bearing is formed as a clogging surface. Leakage of the lubricating oil in the hole can be reduced, and the hydraulic pressure at the sliding receiving surface can be kept high. And a preferable lubricating state can be maintained.
[0016]
  Furthermore, the present invention forms a tapered edge that expands in diameter on one and other surface ends of the sliding receiving surface, and at least one of the tapered edges is formed as a non-clogging surface that does not clog the surface layer holes. A sintered oil-impregnated bearing is provided.
[0017]
  According to this sintered oil-impregnated bearing, it is possible to prevent leakage of the lubricating oil in the air holes from the outer surface of the clogged bearing body and to keep the hydraulic pressure at the sliding receiving surface high, Since at least one of the holes in the surface layer is formed as a non-clogging surface that does not clog the surface, the lubricating oil that overflows from between the inner diameter surface of the sintered oil-impregnated bearing and the shaft body and the bearing from the taper edge to the bearing. It is possible to return to the shaft body. Therefore, a decrease in the amount of oil in the sintered oil-impregnated bearing can be prevented, and a preferable lubricating state of the sintered oil-impregnated bearing can be maintained over a long period of time.
[0018]
  As another means for achieving the above-described object, the present invention provides a hole in the bearing body formed with a cylindrical sliding receiving surface that rotatably supports the shaft body along the axial direction. It is oil-impregnated and attached via a bracket to a predetermined position in the device.In the present inventionThe oil retaining structure in the hole of the sintered oil-impregnated bearing, wherein the outer surface of the bearing body excluding the sliding receiving surface and the contact surface with the bracket is formed as a clogging surface clogging the surface layer hole, The sintered oil-impregnated bearing characterized in that the oil pressure in the hole of the sintered oil-impregnated bearing is maintained by using the clogging surface and the contact surface of the bracket with the sintered oil-impregnated bearing as a return surface of the oil impregnated in the hole. Provide a hydraulic holding structure in the hole.
[0019]
According to this hydraulic holding structure in the hole, the outer surface of the sintered oil-impregnated bearing other than the inner diameter surface serving as the sliding receiving surface is clogged or the contact surface with the unclogged bracket is also connected to the bearing body. Since the bracket is in airtight contact, the bracket surface can act as a return surface for oil impregnation in the holes and reduce leakage of oil impregnation in the holes from the bearing body. As in the case of clogging, the lubricating oil pressure on the sliding receiving surface can be kept high. Therefore, it is possible to maintain smooth rotation of the shaft body over a long period of time.
[0020]
  Further, the present invention comprises an oil impregnation treatment in a hole of a bearing body formed with a cylindrical sliding receiving surface that rotatably supports a shaft body along an axial direction, and is provided at a predetermined position in an apparatus. Can be attached to bracket via adhesiveIn the present inventionThe oil retaining structure in the hole of the sintered oil-impregnated bearing, wherein the outer surface of the bearing body excluding the sliding receiving surface and the adhesion surface with the bracket is formed as a clogging surface clogging the surface layer hole, Provided is an in-hole hydraulic pressure retaining structure for a sintered oil-impregnated bearing, wherein the pore-sealing surface and the adhesive material surface are used as a return surface for the oil-impregnated pore interior to retain the oil pressure in the hole.
[0021]
According to this hydraulic holding structure in the hole, the outer surface of the sintered oil-impregnated bearing other than the inner diameter surface serving as the sliding receiving surface is clogged, or the adhesive surface with the unfilled bracket is also sintered and impregnated. The surface of the adhesive used to bond the bearing to the bracket serves as a return surface for the oil content in the air holes, so that leakage of the oil content in the air holes from the bearing body can be suppressed, and sliding of the bearing body As in the case where the outer surface other than the receiving surface is clogged, the lubricating oil pressure on the sliding receiving surface can be maintained high, and the smooth rotation of the shaft body can be maintained over a long period of time.
[0024]
  As still another means for achieving the above object, the present invention provides a cylindrical slide receiving surface that rotatably supports the shaft body, and is provided on one outer surface of the bearing body excluding the slide receiving surface. Clogging surface vacancies in part or allTheRegarding the manufacturing method of sintered oil-impregnated bearings, a sintered compact bearing body is primarily sintered, and part or all of the outer surface of the bearing body excluding the sliding bearing surfaceIn the surface vacancies inCrimp metal powderEmbeddedAnd this metal powderEmbeddedSecondary sintering the bearing body, With a thickness of 0.005 to 0.015 mmCharacterized by cloggingCloggedA method for producing a sintered oil-impregnated bearing is provided.
[0025]
According to this method of manufacturing a sintered oil-impregnated bearing, a part or all of the outer surface of the bearing body excluding the sliding bearing surface can be formed as a clogging surface clogging the surface layer pores. The lubricating oil filled in the air holes of the bearing can be prevented from leaking to the outside of the sintered oil-impregnated bearing from the surface other than the inner diameter surface of the sintered oil-impregnated bearing that becomes the sliding bearing surface with the shaft body. Thus, it is possible to obtain a sintered oil-impregnated bearing capable of maintaining a high lubricating oil pressure.
[0026]
  And since metal is used as a packing material and the packing material is fixed by sintering, a predetermined bearing surface can be reliably plugged, and a hole opened in the bearing surface as a plugging surface can be formed. It is possible to clog, maintain a high hydraulic pressure on the sliding receiving surface, and maintain a preferable lubrication state. Further, the clogging material is hardly peeled off, and the clogged state can be maintained for a long time. Furthermore, it can be manufactured at low cost.
[0027]
  The pressure bonding of the metal powder can be performed by applying pressure to the metal powder and embedding it in the holes of the bearing body, the metal powder is bronze alloy powder, and the bearing body is made of a bronze alloy. And a method for producing a sintered oil-impregnated bearing made of a mixed powder of iron and copper alloy.
[0030]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of a sintered oil-impregnated bearing (hereinafter abbreviated as “bearing”) and an in-hole hydraulic pressure retaining structure of the present invention will be described with reference to the drawings. In the following embodiments, a bearing for a drive motor that rotationally drives a music CD in a CD player will be described as an example.
[0031]
FIG. 1 is a longitudinal sectional view showing a state in which a shaft body 13 of a drive motor that rotationally drives a music CD is supported by a bearing 12 attached to a bracket 11. The shaft body 13 is supported in the radial direction by the inner diameter surface of the cylindrical bearing 12 being a sliding receiving surface 14, and is supported in the axial direction by a resin thrust bearing 15. The resin thrust bearing 15 is attached to a recess 17 formed in the bottom 16 of the bracket 11.
[0032]
The bearing 12 has a cylindrical shape, and an inner diameter surface thereof is a sliding receiving surface 14 that receives rotational sliding of the shaft body 13. At the upper and lower surface ends of the sliding receiving surface 14, tapered edges 18 and 19 that expand outward are formed. The sliding bearing surface 14, the outer diameter surface 20 of the bearing 12, an upper surface 21 (adjacent surface) continuous to the upper surface end of the sliding bearing surface 14, and a lower surface 22 (continuous to the lower surface end of the sliding bearing surface 14 The “outer surface” of this bearing 12 is formed by the adjacent surface) and the tapered edges 18, 19. Of the “outer surface”, the outer surface 20, the upper surface 21 and the lower surface 22, and the tapered edge 19 except for the sliding receiving surface 14 and the tapered edge 18 are clogged with a packing material. It has a “clogging surface”.
[0033]
Next, the operation of the bearing 12 having the above schematic configuration will be described. When the shaft body 13 is rotated, a claw rotation as shown by a chain line in FIGS. 6 and 7 is performed. At this time, in the case of a conventional bearing, as shown in FIG. 2 (a), the upper surface, the lower surface, and the outer surface pores of the outer diameter surface of the bearing 1 are not clogged clogging surfaces. It will be pushed into the bearing. However, as described above, the surface layer holes of the outer diameter surface 20, the upper surface 21, the lower surface 22, and the lower taper edge 19 except for the sliding receiving surface 14 and the upper taper edge 18 are clogged with the packing material. In the bearing 12 of this embodiment having a “packing surface”, as shown in FIG. 2 (b), even if the lubricating oil is pushed in, the “in-hole lubricating oil” does not escape to the outside through the surface hole. Since it is in a state of being sealed with the “filling surface”, leakage of the lubricating oil in the pores to the outside is suppressed. Therefore, an appropriate lubricating oil pressure is applied to the sliding receiving surface 14 where the surface layer holes are not crushed. Therefore, in this bearing 12, the lubricating oil pressure of the sliding receiving surface 14 can be maintained high, and the smooth rotation of the shaft body 13 can be maintained over a long period of time.
[0034]
And since the lubricating oil pressure in the sliding bearing surface 14 can be maintained high in this way, even when the shaft body 13 rotates through a slit, the clearance between the shaft body 13 and the sliding bearing surface 14 of the bearing 12 can be increased. There is no need to increase the viscosity of the lubricating oil.
[0035]
1 shows an example in which the “outer surface” of the bearing 12 excluding the sliding receiving surface 14 and the tapered edge 18 is a “clogging surface”, but all of these surfaces must be clogging surfaces. is not. For example, if the lubricating oil in the hole does not leak from the outer diameter surface 20 of the bearing 12 because it is in airtight contact with the bracket 11, the outer diameter surface 20 can be not clogged. In such a case, the oil pressure of the lubricating oil contained in the air holes in the bearing 12 is maintained by installing the bearing 12 and the bracket 11 in an airtight manner. In addition, when the airtightness between the bearing 12 and the bracket 11 cannot be maintained, the bearing 12 is fixed to the bracket 11 with an adhesive so that the lubricating oil in the hole does not leak from the bearing 12. Is possible. However, it is preferable to provide as many clogging surfaces as possible from the viewpoint of improving the lubrication characteristics because the risk of leakage of the lubricating oil in the pores is reduced, and most preferably, the outer surface of the bearing body excluding the sliding receiving surface is preferred. The entire surface is a clogged clogged surface.
[0036]
Further, as shown in FIG. 2 (b), the upper tapered edge 18 removes lubricating oil overflowing from between the inner diameter surface of the bearing 12 and the shaft body 13, and the sliding receiving surface 14 of the bearing 12 and the shaft body 13. However, when it is necessary to further suppress the leakage of the lubricating oil in the pores to the outside, the upper tapered edge 18 may be clogged. Further, if there is a high demand for returning the lubricating oil overflowing from the bearing 12 to the sliding receiving surface 14, not only the upper taper edge 18 but also the lower taper edge 19 may not be clogged. However, when the bearing 12 pivotally supports the shaft body 13 so that the longitudinal direction of the shaft body 13 is oriented horizontally, both the one and the other tapered edges are often clogged or not clogged. When the bearing 12 pivotally supports the shaft body 13 so that the longitudinal direction of the shaft body 13 is directed vertically, the lower taper edge 19 is used to suppress leakage of the oil content in the holes below the bearing 12. It is preferable that the upper tapered edge 18 is not clogged in order to return the lubricating oil that has been packed and overflowed upward to the bearing 12 into the bearing 12. In the present embodiment, the taper edges 18 and 19 are provided at both surface ends of the sliding receiving surface 14 of the bearing 12, but there may be a case where the taper edges 18 and 19 are provided at only one of the surface ends. In this case, whether or not the tapered edge is clogged is determined by the relationship between the hydraulic pressure at the sliding receiving surface 14 and the necessity of returning the oil to the bearing 12.
[0037]
The raw material of the bearing 12 can be a raw material used for a general sintered oil-impregnated bearing. Examples of the powder metal include iron powder, copper powder, a mixture of iron powder and copper powder, and graphite powder. , Tin powder, zinc powder, lead powder, etc., or other alloys added, iron-based alloy powder, such as Fe-C, Fe-Pb-C, Fe-Cu-C alloy, etc. Alternatively, other alloys such as copper-based alloy powders such as Cu—Sn, Cu—Sn—C, Cu—Sn—Pb—C alloys, and the like can be used. Usually, it is preferable to use an alloy having both the advantages that the iron-based alloy has high mechanical strength, high hardness, and low cost, and the advantage that the copper-based alloy has excellent lubrication characteristics.
[0038]
The bearing 12 can be manufactured by using a general powder metallurgy method, and can be performed by adding a step of clogging the outer surface of the bearing 12 in the middle of the manufacturing process. For example, various metal powders as raw materials are mixed, filled in a mold, and then compressed by a press to a predetermined shape, which is held at a high temperature in a sintering furnace and sintered. Then, after adjusting the size and density of the sintered body by sizing, post-processing steps such as washing and oil impregnation are sequentially performed. Among these processes, the clogging process is performed at a stage after compacting and before cleaning.
[0039]
For example, a metal or a resin can be selected as the material used for the filling (a filling material), and the filling method can also be selected according to the material.
[0040]
When a metal is used for the filling material, there are a method of melting bronze, iron, copper or the like to coat the outer surface, or a method of filling using the metal for bearings pulverized into fine powder. The method of clogging with powder metal requires that the powder metal be buried in the holes of the bearing 12 and not fall off, and the metal powder is buried in the holes by applying mechanical pressure from the outside, There is also a method in which metal powder is attached to the outer surface of the bearing 12 and heated or melted or sintered. There is also a method in which metal powder is adhered to the outer surface of the bearing 12 with an adhesive. However, the method of utilizing the phenomenon that the alloy ground flows during the cutting process, or the method of clogging using the fact that the cavities are filled with the chips, has insufficient pores and the clogged holes are not clogged. In addition to remaining considerably, it is uneconomical and is not preferable as a clogging method.
[0041]
Various resins such as acrylic resins, polycarbonate resins, ester resins, ABS resins, polypropylene resins, amino resins, phenol resins, polyamide resins, epoxy resins, polyurethane resins, etc. Etc. can be used. When a thermoplastic resin such as an acrylic resin is used, it is possible to coat the outer surface of the bearing 12 with a resin layer by applying it to the outer surface using a coating solution in which the resin is dissolved in a solvent and drying it. Moreover, when using thermosetting resins, such as an epoxy resin, the method of hardening resin after apply | coating to the outer surface of the bearing 12 can be used.
[0042]
Whichever clogging method is employed, the outer surface of the bearing 12 may be clogged and the clogging material may be fixed to the outer surface of the bearing 12, and the thickness is not particularly limited. A thickness of about 0.015 mm is preferable from the viewpoints of durability and economy. In addition, the micrograph of the cross section of the bearing 12 clogged by the method of the present invention (the two photos on the left side of FIG. 3) is a micrograph of the cross section of the sintered oil-impregnated bearing that is not clogged (the two photos on the right side of FIG. This is shown in FIG. From the photograph of FIG. 3, it can be seen that the surface of the bearing 12 is clogged with a thickness of about 0.010 mm. In order to clearly show the clogged state in the photograph, a bearing is made using SBF type 1 (JIS B1581) made of pure iron, and copper powder is used for clogging.
[0043]
The degree of clogging is preferably 95% or more, preferably 99% or more, of the surface layer pores on the surface to be crushed. This is because if less than 95%, the clogging effect is also poor.
[0044]
【Example】
EXAMPLES Hereinafter, although this invention is demonstrated in more detail based on an Example, this invention is not limited to this Example.
[0045]
Example 1:(Compact molding → Sintering → Filling → Re-sintering → Secondary molding → Post-processing)
[0046]
  Bronze alloy powder (copper: tin = 9: 1 (weight)); 60 wt% and iron-copper alloy powder (iron: copper = 9: 1 (weight)); 40 wt% are mixed, compression molded, and cylindrical A green compact (inner diameter x outer shape x full length = 3 mm x 7 mm x 7 mm) was obtained. The green compact was subjected to primary sintering at 800 ° C. for 20 minutes in a hydrogen atmosphere sintering furnace. next, BlueThe copper alloy powder was pressure-bonded to the outer surface excluding the inner diameter surface of the green compact. This was subjected to secondary sintering (re-sintering) at 800 ° C. for 20 minutes in a hydrogen atmosphere sintering furnace. Thereafter, surface treatment such as deburring was performed, and washing and impregnation with oil (20 # synthetic oil) were performed to obtain Sample 1.
[0047]
  Example 2:(Compact molding → Filling → Sintering → Secondary molding → Post-processing)
[0048]
The green compact obtained in the same manner as in Example 1 was packed without sintering. The same material as used in Example 1 was used for filling. Thereafter, sintering was performed at 800 ° C. for 20 minutes in a hydrogen atmosphere sintering furnace. This was subjected to surface treatment such as deburring, washing, and impregnation with oil (20 # synthetic oil) to obtain Sample 2.
[0049]
  Example 3:(Compact molding → Sintering → Secondary molding → Filling → Post-processing)
[0050]
The green compact obtained in the same manner as in Example 1 was sintered in a hydrogen atmosphere sintering furnace at 800 ° C. for 20 minutes, and then subjected to surface treatment such as deburring. An acrylic resin varnish (resin content 15 wt%, balance toluene) was applied to the outer surface excluding the inner diameter surface of the sintered body and dried. This was washed and impregnated with oil (20 # synthetic oil) to obtain Sample 3.
[0051]
  Example 4:
[0052]
Sample 4 was obtained in the same manner as in Example 1 except that in the clogging step, the outer surface other than the inner diameter surface and the outer diameter surface of the green compact was clogged. For sample 4, an acrylic resin adhesive was applied to the outer diameter surface of sample 4 when mounted on the bracket.
[0053]
Comparative Example 1:
[0054]
Sample 5 was obtained in the same manner as in Example 1 except that the clogging step was omitted.
[0055]
Torque test:
[0056]
Sample 1 and Sample 5 obtained in Example 1 and Comparative Example 1 were each mounted on a hard resin bracket. A shaft body with a clearance of 2 μm was passed through each of the samples 1 and 5 attached to the bracket, and the operating torque of the shaft body was measured. The measurement of the operating torque assumes a fan motor bearing, and the peripheral speed applied to the shaft body is 75 m / min. (8000 rpm); assuming that the surface pressure applied to the bearing is 0.85 kg / cm and a bearing of a disk rotation motor of a CD-ROM drive device, the peripheral speed applied to the shaft body is 113 m / min. (12000 rpm): It was performed under two conditions when the surface pressure applied to the bearing was 0.85 kg / cm. The results are shown in FIGS. 4 (a) and 4 (b), respectively. Under any measurement condition, the sample 1 that has been clogged (“cuffed product” in FIG. 4) has a torque that is greater than that of the sample 5 that has not been clogged (“uncapped product” in FIG. 4). The value is low. As a result, it can be seen that the clogged bearings are superior in operational stability and have a longer product life than non-clogged bearings.
[0057]
【The invention's effect】
According to the sintered oil-impregnated bearing of the present invention, the hydraulic retaining structure in the hole, and the method for producing the sintered oil-impregnated bearing, the lubricating oil filled in the holes of the bearing body clogs the surface holes. This suppresses leakage from the outer surface other than the sliding bearing surface to the outside of the sintered oil-impregnated bearing, so that the lubricating oil pressure on the sliding bearing surface is kept high, and a preferable lubrication state can be maintained. In addition, the oil pressure retaining structure in the hole can be obtained.
[0058]
Moreover, according to the sintered oil-impregnated bearing of the present invention, the hydraulic pressure retaining structure in the hole, and the method for producing the sintered oil-impregnated bearing, it can be manufactured at a low cost and the product life is extended.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing an installation state of a sintered oil-impregnated bearing of the present invention.
FIG. 2 is a conceptual diagram showing the flow of lubricating oil in holes in the sintered oil-impregnated bearing of the present invention.
FIG. 3 is a photomicrograph of a cross section of each of a clogged surface and an unclogged surface of a sintered oil-impregnated bearing of the present invention.
FIG. 4 is a graph showing the results of an operating torque test, and a partial diagram (a) shows a peripheral speed of 75 m / min. The partial diagram (b) shows that the peripheral speed is 113 m / min. It is a case where it measures on condition of this.
5 is a schematic diagram corresponding to the section taken along the line SA-SA in FIG. 6 for explaining the operating principle of a general oil-impregnated bearing.
FIG. 6 is a conceptual diagram showing, in a longitudinal section, a state in which a shaft rotates in a sawtooth manner.
FIG. 7 is a conceptual diagram showing a state in which a shaft rotates in a sawtooth manner in a cross section.
[Explanation of symbols]
1,12 Sintered oil-impregnated bearing ("Bearing" or "Bearing body")
2,13 shaft
3,14 Sliding bearing surface
4 Lubricating oil
11 Bracket
15 Thrust bearing
16 Bottom of bracket
17 recess
18 Upper taper edge
19 Lower taper edge
20 Outer surface
21 Upper surface (adjacent surface)
22 Lower surface (adjacent surface)

Claims (11)

Cylindrical sliding receiving surface for rotatably journaling the shaft body is formed, an oil impregnated sintered bearing in which plugged the surface pores for some or all of the outer surface of the bearing body with the exception of sliding bearing surface In the manufacturing method of
The sintered compacted bearing body is primarily sintered, and metal powder is pressure-bonded and embedded in the surface layer voids on the outer surface of a part or all of the bearing body except for the sliding receiving surface, and this metal powder is embedded. A method of manufacturing a packed sintered oil-impregnated bearing, wherein the bearing body is secondarily sintered and packed in a thickness of 0.005 to 0.015 mm . The method for producing a packed sintered oil-impregnated bearing according to claim 1, wherein 95% or more of the surface layer holes are packed. The method for producing a packed sintered oil-impregnated bearing according to claim 1 or 2, wherein the metal powder is bronze alloy powder. The method for producing a packed oil-impregnated bearing according to any one of claims 1 to 3, wherein the bearing body is made of a mixed powder of a bronze alloy and an iron-copper alloy. It has a cylindrical sliding bearing surface that rotatably supports the shaft body, and the surface layer holes that appear on the outer surface of part or all of the bearing body excluding the sliding bearing surface are packed with metal powder. In a sintered oil impregnated bearing,
Becomes a secondary sintered body of metal powder pressed to the surface pores of the bearing body and the bearing body made by the primary sintered body, 0. A sintered oil-impregnated bearing characterized by clogging the surface layer pores with a thickness of 005 to 0.015 mm.   The sintered oil-impregnated bearing according to claim 5, wherein the metal powder is a bronze alloy powder.   The sintered oil-impregnated bearing according to claim 5 or 6, wherein the bearing body is made of a mixed powder of bronze alloy and iron-copper alloy.   The sintered oil-impregnated bearing according to any one of claims 5 to 7, wherein an adjacent surface continuous with the sliding receiving surface is clogged among outer surfaces of the bearing body.   A taper edge that expands in diameter is formed on one and other surface ends of the sliding receiving surface, and at least one of the taper edges is a non-clogging surface that does not clog surface layer holes. The sintered oil-impregnated bearing according to any one of claims. The bearing body hole is formed with a cylindrical slide receiving surface that rotatably supports the shaft body along the axial direction, and is subjected to oil impregnation treatment, and is attached to a predetermined position in the machine via a bracket. A structure for retaining hydraulic pressure in pores of a sintered oil-impregnated bearing according to any one of claims 5 to 9,
The outer surface of the bearing body excluding the sliding receiving surface and the contact surface with respect to the bracket is formed as a clogging surface clogging the surface layer holes, and the contact surface between the clogging surface and the sintered oil-impregnated bearing of the bracket Is used to hold the oil pressure in the hole of the sintered oil-impregnated bearing, and the oil pressure return surface of the oil-impregnated hole in the hole. An oil-impregnated treatment is applied to the holes in the bearing body formed with a cylindrical sliding bearing surface that rotatably supports the shaft body along the axial direction. The oil retaining structure for pores in a sintered oil-impregnated bearing according to any one of claims 5 to 9, which is attached to
The outer surface of the bearing body excluding the sliding receiving surface and the adhesive surface with the bracket is formed as a clogging surface clogging the surface layer voids, and the clogging surface and the adhesive material surface are included in the voids. A structure for holding oil pressure in a hole of a sintered oil-impregnated bearing, wherein the oil pressure in a hole is held as an oil return surface.

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