JP5352978B2 - Manufacturing method of sintered bearing - Google Patents

Abstract

A powder compact which gives a sintered bearing having excellent adhesion to a resinous coating layer; a sintered bearing obtained by sintering the powder compact; and processes for producing the compact and the bearing. A raw powder (M) is compacted between a molding core rod (13) having fine core-rod-side recesses and protrusions (18) on a peripheral surface thereof and a molding die (12) to form a powder compact (1A). Thus, the fine core-rod-side recesses and protrusions (18) are transferred to the bearing bore of the powder compact (1A). Namely, a powder compact (1A) having the fine recesses and protrusions can be produced. This powder compact (1A) is sintered to give a sintered bearing. A resinous coating layer is formed on the wall of the bearing bore having fine recesses and protrusions of this sintered bearing. Thus, a sintered bearing having excellent adhesion to the resinous coating layer can be produced.

Description

The present invention relates to a method for producing a Shoyuijiku received.

  This type of sintered bearing forms a green compact by compressing a raw material powder consisting mainly of metal with a powder molding machine, and sintering the green compact in a sintering furnace to form a sintered body. To do.

  Such sintered bearings can be manufactured not only by stable quality and mass production, but also by using a material having a composition that is difficult with melted materials, and can produce a porous body. Has many advantages.

  Utilizing such properties, an oil-impregnated bearing (for example, Patent Document 1) capable of causing the lubricating oil absorbed in the pores of the porous body to ooze out uniformly from the surface, or has good lubricity It can be used in places where there is little effort to replenish lubricating oil such as dry bearings (dry friction bearings) where lubricating oil is unnecessary by including fluororesin material in the material powder, and it has been widely used in the past. It has been.

Further, it is known to apply a resin coating containing a solid lubricant as a coating on the surface of the sliding member (for example, Patent Document 2), and the resin coating layer enters the pores of the sintered bearing body, Resin coating with high adhesion can be performed (for example, Patent Document 3).
JP-A-6-173953 JP-A-8-109352 JP 2004-108461 A

  As in Patent Document 3, since the sintered alloy has pores on the surface, it has excellent adhesion to a resin coating or the like. Moreover, if unevenness is formed by machining on the surface of the sintered alloy after sintering, peeling of the resin coating can be prevented even during long-term use, and adhesion can be improved.

  However, in order to perform machining on the sintered alloy, there is a problem that the number of manufacturing steps is increased separately, resulting in a decrease in productivity and an increase in cost.

  The present invention is intended to solve such problems, and an object thereof is to provide a sintered bearing capable of obtaining a sintered bearing excellent in adhesion of a resin coating layer and a method for producing the same.

According to the first aspect of the present invention, the raw material powder is filled in a filling portion formed between the molding die of the molding die, the molding core rod, and the lower punch, and this raw material powder is added by the upper punch and the lower punch. The green compact having a bearing hole is compressed and compressed , and after the compression formation, the upper punch rises relatively above the molding die and is relatively relative to the molding core rod and the lower punch. When the molding die descends, the green compact is discharged from the molding die, and the spring core of the green compact after discharging allows the molding core rod to be pulled out from the bearing hole. In the manufacturing method of the sintered bearing formed by sintering the green compact, the forming core rod having a fine core rod side uneven portion formed by electric discharge machining on the outer peripheral surface and having a random core rod side uneven portion; and Molding Between the die, by forming the green compact by compressing the raw powder, transferring the fine core rod side uneven portions in the bearing hole of the green compact, the bearing hole of the powder compact This is a method of manufacturing a sintered bearing in which a fine bearing is formed after sintering to form a sintered bearing, and a resin coating layer is provided in the bearing hole of the sintered bearing .

Moreover, invention of Claim 2 is a manufacturing method of the sintered bearing whose height of the said uneven | corrugated | grooved part is 5-40 micrometers.

The invention of claim 3 is a method for manufacturing a sintered bearing , wherein the height of the irregularities on the core rod side is 5 to 40 μm.

According to the configuration of the first aspect , since the fine irregularities are provided in the bearing hole in the green compact, the sintered compact having the fine irregularities in the bearing hole is manufactured by sintering the green compact. be able to.

Moreover, according to the structure of Claim 1, the sintered compact which has a fine uneven | corrugated part in a bearing hole can be manufactured.

Moreover, according to the structure of Claim 1, the sintered bearing excellent in adhesiveness with the resin coating layer can be manufactured.

Further, according to the configuration of the first aspect , since the core rod side uneven portion is transferred to the green compact during compression molding of the green compact, machining or the like is not required for forming the concave and convex portion, thereby improving the production efficiency. Can do.

Moreover, according to the structure of Claim 1 , a green compact can be extracted from a core rod using the spring back of a green compact, and a fine uneven part is formed in a bearing hole in a normal compression molding process. be able to.

Moreover, according to the structure of Claim 2, the sintered bearing excellent in the adhesiveness of the resin coating layer can be manufactured, without impairing extraction by springback.

Moreover, according to the structure of Claim 3, since the depth of the uneven | corrugated | grooved part of a sintered bearing will become small when the height of the uneven | corrugated | grooved part on the core rod side is 5-40 micrometers and the height is less than 5 micrometers, it is an adhesion effect. On the other hand, if it exceeds 40 μm, there is a possibility that the extraction by the spring back may be impaired, and by setting the above range, it is suitable for production and has excellent adhesion.

Preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The embodiments described below do not limit the contents of the present invention described in the claims. In addition, all of the configurations described below are not necessarily essential requirements of the present invention. In each embodiment, by adopting a new sintered bearing different from the conventional one and its manufacturing method, an unprecedented sintered bearing and its manufacturing method are obtained, and the sintered bearing and its manufacturing method are described respectively.
(Reference Example 1)

Hereinafter, a reference example of the present invention will be described. FIGS. 1 to 6 show a reference example 1 according to the basic configuration of the present invention. As shown in FIG. A bearing body 3 formed of a porous sintered alloy having pores) is provided with a bearing hole 3, has a substantially cylindrical shape, and has an outer diameter smaller than that of the bearing hole 3. A rotating shaft (not shown) is inserted and used. And the fine uneven part 4 is provided in the internal peripheral surface of the bearing hole 3, and the resin coating layer 5 is provided in this uneven part 4. As shown in FIG.

  Next, an example of a method for manufacturing the sintered bearing 1 will be described. The bearing body 2 is formed by pressing a raw powder M such as Cu-Su-C or Fe to form a green compact 1A, and after firing the powder, correct the shape as necessary. It is formed by.

  1 to 5 show a molding die 11, which shows a state in which a green compact 1A is pressure-molded from a raw material powder M. FIG. As shown in the figure, the molding die 11 used for molding the green compact 1A has the vertical direction as the axial direction (press vertical axis direction), and includes a molding die 12, a molding core rod 13, a lower punch 14, and An upper punch 15 is provided. The die 12 has a substantially cylindrical shape, and a substantially cylindrical core rod 13 is coaxially positioned in the die 12. The lower punch 14 has a substantially cylindrical shape and is fitted between the die 12 and the core rod 13 so as to be vertically movable from below. The upper punch 15 has a substantially cylindrical shape and is fitted between the die 12 and the core rod 13 so as to be movable up and down from above and to be detachable. A filling portion 16 having an open top is formed between the die 12, the core rod 13, and the lower punch 14, and the outer peripheral surface 17 of the core rod 13 forms the bearing hole 3.

  On the outer peripheral surface 17 of the core rod 13, fine core rod side uneven portions 18 are formed by machining or the like corresponding to the three bearing holes. In this example, the concavo-convex portion 18 has a shape in which a convex portion 19 having a triangular cross-section and a concave portion 20 having a triangular cross-section are alternately formed in the length direction of the core rod 13. The outer diameter Dg of the outer end of the outer peripheral surface 17 is the same as the outer diameter D of the outer peripheral surface 17, the outer diameter Dn of the inner end of the recessed portion 20 is smaller than the outer diameter D, and the height H of the concavo-convex portion 18 is set. 5 to 40 μm. In this case, if the height H is less than 5 μm, the depth of the concavo-convex portion 4 of the sintered bearing 1 becomes small, so that a sufficient adhesion effect cannot be obtained. On the other hand, a larger one is preferable, but if it exceeds 40 μm There is a possibility that the extraction by the spring back described later is impaired.

  In the filling step shown in FIG. 1, the filling part 16 is filled with the raw material powder M, and in the compression step shown in FIG. 2, the upper and lower punches 15 and 14 press the raw material powder M in the filling part 16. Thus, by compressing the green compact 1A, the fine irregularities 18 of the core rod 13 are transferred to the bearing holes 3 of the green compact 1A, and the irregularities 4 are formed. Further, in the subsequent extraction step, as shown in FIG. 3, the upper punch 15 rises relatively above the die 12, and the die 12 descends relative to the core rod 13 and the lower punch 14. When the green compact 1A is discharged from the die 12, the diameter of the green compact 1A is slightly expanded by the spring back. As a result, the diameter of the green compact 1A expands and the core rod 13 descends, whereby the core rod 13 can be pulled out from the green compact 1A as shown in FIG. 4, and the bearing hole of the discharged green compact 1A The concavo-convex portion 4 can be formed on the surface 3.

  Although depending on the dimensions of the green compact 1A and molding conditions, the green compact 1A expands the inner diameter of the bearing hole 3 by about 0.2% due to the spring back.

  The present invention is characterized in that the concave and convex portion 4 is formed in the bearing hole 3 after the green compact 1A is formed and before sintering.

  The green compact 1A thus molded is sintered to form the sintered bearing 1 which is a sintered alloy. Then, a resin coating is applied to the bearing hole 3 of the sintered bearing 1 to form a resin coating layer 5. As shown in FIG. 5, the chamfered portion 6 is formed by chamfering the outer peripheral surface of the sintered bearing 1 and the both end corners of the bearing hole 3 as necessary before resin coating.

  In particular, the resin coating layer 5 is preferably a fluororesin layer. As the fluororesin, tetrafluoroethylene resin (PTFE (Teflon (registered trademark)), tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA) is used. (Teflon (registered trademark)) or tetrafluoroethylene-hexafluoropropylene copolymer (FEP (Teflon (registered trademark))) or the like.

  In addition, a solid lubricant paint can be used for the resin coating, and this solid lubricant paint is obtained by dispersing a large amount of solid lubricant fine particles in a binder solution obtained by dissolving a binder resin in a solvent. Examples of the binder resin include polyamide imide, epoxy, furan, melamine, acrylic, urethane, and the like. In consideration of adhesion and mechanical strength, it is preferable to use amine-curable two-part epoxy. Examples of the solvent include xylene, toluene, butanol, isobutyl alcohol, isopropyl alcohol, dioxane, methyl ethyl ketone, n-methyl-2-pyrrolidone and the like. As solid lubricants, PTFE (Teflon (registered trademark)), PFA (Teflon (registered trademark)), FEP (Teflon (registered trademark), C (graphite), MoS2 (molybdenum disulfide), BN (boron nitride), WF, (Tungsten fluoride), TiN (titanium nitride) and the like are exemplified, and these can be used alone or in combination.

  Thus, by providing the resin coating layer 5 in the bearing hole 3 having the fine uneven portion 4, the resin coating can be easily performed, and high adhesion can be obtained without peeling over a long period of time. Moreover, in this example, since the uneven part 4 can be formed simultaneously with the compression molding process of the green compact 1A, the productivity is excellent.

  And after providing the resin coating layer 5, the sintered bearing 1 is sized as needed.

Thus, in the present reference example, the green compact 1A with raw material powder M is filled into the filling portion 16 of the mold 11, the bearing hole 3 formed by molding the raw material powder M is pressurized, the bearing hole 3 Since the fine uneven portion 4 is provided in the bearing hole 3 in the green compact 1A, the fine uneven portion 4 is formed in the bearing hole 3 by sintering the green compact 1A. A sintered body having the same can be obtained. The fine irregularities 4 provide excellent adhesion to the coating provided in the bearing hole 3.

Also, in this way the reference example, since the resin coating layer 5 provided on the shaft receiving hole 3, the sintered bearing 1 having excellent adhesiveness to the resin coating layer 5 is obtained.

As described above, in this reference example, the raw material powder M is filled in the filling portion 16 of the molding die 11, and after pressing the raw material powder M to form the green compact 1 A having the bearing hole 3, In the manufacturing method of the green compact 1A that forms the sintered bearing 1, the fine irregularities 4 are formed in the bearing hole 3 of the green compact 1A. Since the uneven portion 4 is provided, a sintered body having the fine uneven portion 4 in the bearing hole 3 can be manufactured by sintering the green compact 1A.

Further, such a present embodiment, the raw material powder M is filled into the filling portion 16 of the mold 11, molding a green compact 1A having a bearing hole 3 pressurizes the raw powder M, the In the manufacturing method of the sintered bearing 1 formed by sintering the green compact 1A, the fine irregularities 4 are formed in the bearing hole 3 of the green compact 1A and then sintered. A sintered body having the portion 4 can be manufactured.

Also, in this way the reference example, the bearing hole 3 of the sintered bearing 1, since providing the resin coating layer 5, it is possible to produce a sintered bearing 1 which is excellent in adhesion to the resin coating layer 5.

Also, in this way the reference example, and molding core rod 13 having an outer peripheral surface 17 a fine core rod side uneven portion 18, between the forming die 12, a green compact 1A to compress the raw material powder M Since the fine core rod side uneven portion 18 is transferred to the bearing hole 3 of the green compact 1A by forming, the core rod side uneven portion 18 is transferred to the green compact 1A during compression molding of the green compact 1A. Machining or the like is not required for forming the concavo-convex portion 4, and the production efficiency can be improved.

Also, in this way the reference example, after pre-Symbol compression, extracted green compact 1A from the molding die 12 together with the core rod 13, by the spring back of the compact 1A after extracting extracts the core rod 13 from the bearing hole 3 Thus, the green compact 1A can be extracted from the core rod 13 by using the spring back of the green compact 1A in this way, and fine irregularities are formed in the bearing hole by a normal compression molding process. be able to.

The height H of the concave convex portion 4 and the concave-convex portion 18 is about 5 to 40 m, the height H is less than 5 [mu] m, since the depth of the concave-convex portion 4 of the sintered bearing 1 is reduced, the adhesion effect On the other hand, if it exceeds 40 μm, there is a possibility that the extraction by the spring back may be impaired, and by setting the above range, it is suitable for production and excellent in adhesion.

Further, as an effect on the reference example, when a fluororesin is used for the resin coating layer 5, it has excellent durability against corrosion and the like as well as sliding properties.
(Reference Example 2)

7 and 8 show Reference Example 2 of the present invention. The same reference numerals are assigned to the same parts as in Reference Example 1, and detailed description thereof is omitted. The mold 11 has the same configuration as the reference example 1 except that the core rod 13 does not have the core rod side uneven portion, and the molding die 11 forms the green compact 1A without the uneven portion. The uneven portion 4 is formed in the bearing hole 3 of the green compact 1 </ b> A by the processing tool 21. Further, similarly to the reference example 1, after forming the green compact 1A, the uneven portion 4 is formed in the bearing hole 3 before sintering.

  The processing tool 21 includes a rotator 22 that is substantially cylindrical and can be inserted into the bearing hole 3. A longitudinal guide groove 23 is formed on the outer periphery of the rotator 22, and a blade body is formed in the guide groove 23. 24 is provided so as to be movable in the circumferential direction of the rotating body 22. The blade body 24 includes a sliding portion 25 having a substantially constant width that slides in the guide groove 23, and a sharpened portion 26 having a substantially triangular cross section is provided at the tip of the sliding portion 25. A portion 27 is provided. The blade edge uneven portion 27 has a shape in which a convex portion 28 having a triangular cross section and a concave portion 29 having a triangular cross section are alternately formed in the length direction of the blade body 24, and the height of the convex portion 28 and the concave portion 29. H is set to about 5 to 40 μm.

  Then, by moving the blade body 24 to the bottom side of the guide groove 23, the processing tool 21 can be inserted into the bearing hole 3 of the green compact 1A, and after the insertion and placement, the blade body 24 is moved to the outer peripheral side. Then, the concave and convex portions 4 can be formed in the bearing hole 3 by causing the blade body 24 to bite into the bearing hole 3 and rotating the processing tool 21 in this state. After the formation, the blade body 24 is guided again. By moving to the bottom side of the groove 23, the processing tool 21 can be pulled out without hitting the uneven portion 4. The processing tool 21 may be fixed and the green compact 1A may be rotated.

Thus, in the present reference example, the green compact 1A with raw material powder M is filled into the filling portion 16 of the mold 11, the bearing hole 3 formed by molding the raw material powder M is pressurized, the bearing hole 3 Since the fine concavo-convex portion 4 having a height of 5 to 40 μm is provided in the green compact 1A, the fine concavo-convex portion 4 is provided in the bearing hole 3 in the green compact 1A. By sintering the green compact 1A, the bearing hole 3 Thus, a sintered body having fine uneven portions 4 can be obtained. The fine irregularities 4 provide excellent adhesion to the coating provided in the bearing hole 3.

Also, in this way the reference example, since made by sintering a pressure powder 1A, Ru can be produced sintered body having a fine uneven portion 4 into the bearing hole 3.

As described above, in the present reference example, since the resin coating layer 5 is provided in the bearing hole 3 in the sintered bearing 1, the sintered bearing 1 having excellent adhesion of the resin coating layer 5 is obtained.

As described above, in this reference example, the raw material powder M is filled in the filling portion 16 of the molding die 11, and after pressing the raw material powder M to form the green compact 1 A having the bearing hole 3, In the manufacturing method of the green compact 1A to form the sintered bearing 1, the fine irregularities 4 are formed in the bearing hole 3 of the green compact 1A, and the raw material powder M is formed into the molding die 11 In the manufacturing method of the sintered bearing 1, which is filled in the filling portion 16, pressurizes the raw material powder M to form a green compact 1 A having a bearing hole 3, and sinters the green compact 1 A. Since the fine irregularities 4 are formed in the bearing hole 3 of the body 1A and then sintered, and the resin coating layer 5 is provided in the bearing hole 3 of the sintered bearing 1, thus forming the green compact 1A in this way. After that, since the concavo-convex portion 4 is formed in the bearing hole 3 before sintering, the same operations and effects as those of the reference example 1 are achieved.

  In particular, the structure in which the concavo-convex portion 4 is formed in the bearing hole 3 of the green compact 1A before sintering is employed, and the sintered bearing 1 which is a sintered alloy is not machined, but the green compact 1A Since the concavo-convex portion 4 is formed in a state, the processing can be easily performed.

Further, such a present embodiment, the raw material powder M is filled into the filling portion 16 of the mold 11, after forming the green compact 1A having a bearing hole 3 pressurizes the raw powder M, In the manufacturing method of the sintered bearing 1 formed by sintering, fine irregularities 4 are formed in the bearing hole 3 of the green compact 1A, and then sintered. Since the coating layer 5 is provided, the same operations and effects as those of the reference example 1 are achieved.

Further, as an effect on the reference example, the processing tool 21 is provided on the rotating body 22 that is rotatably inserted into the bearing hole, the blade body 24 that is provided on the rotating body 22 so as to be movable in the circumferential direction, and the blade body 24. Since the cutting edge uneven part 27 which forms the uneven part 4 in the bearing hole 3 is provided, the uneven part 4 can be easily formed in the bearing hole 3 of the green compact 1A by using the processing tool 21.
(Reference Example 3)

FIG. 9 shows Reference Example 3 of the present invention. The same reference numerals are assigned to the same parts as those of the above Reference Examples, and detailed description thereof is omitted. In this example, the core rod side provided on the core rod 13 is described. This is a modification of the concavo-convex portion, and a ridge (not shown) having a substantially curved cross section is provided around the outer periphery of the core rod 13 at a predetermined interval in the length direction. The predetermined interval is 1 mm, the width of the protrusion in the core rod length direction is approximately 300 μm, and the depth is approximately 5 μm to 40 μm, preferably about 10 to 20 μm.

  Therefore, a fine uneven portion 31 is formed in the bearing hole 3 of the green compact 1A to which the protrusion is transferred. The uneven portion 31 has a concave portion 32 having a curved cross section. It is formed with an interval K of about 1 mm in the vertical direction, and a convex portion 33 is formed between the concave portions 32 and 32. And the width W of the said recessed part 32 is about 300 micrometers, and the depth F is about 5-40 micrometers, Preferably it is about 10-20 micrometers.

  The concave portion 32 may be formed by the processing tool 21. In this case, the blade uneven portion 27 of the processing tool 21 may be formed in a shape corresponding to the uneven portion 31.

As described above, in the present reference example, since the fine uneven portion 31 is provided in the bearing hole 3 of the green compact 1A, the same operations and effects as the above-described reference examples are achieved.
(Reference Example 4)

FIG. 10 shows a reference example 4 of the present invention. The same reference numerals are given to the same parts as the above-mentioned reference examples, and detailed description thereof will be omitted. In this example, the core rod side provided on the core rod 13 is described. This is a modification of the concavo-convex portion, and a longitudinal ridge (not shown) in the longitudinal direction is formed at substantially equal intervals in the circumferential direction on the outer periphery of the core rod 13, and the longitudinal ridge has a substantially curved cross section. The circumferential width is about 300 μm, and the depth is about 5 μm to 40 μm, preferably about 10 to 20 μm.

  Therefore, a fine uneven portion 41 is formed in the bearing hole 3 of the green compact 1A to which the vertical protrusions are transferred. The uneven portion 41 has a concave portion 42 having a curved cross-section and a periphery of the bearing hole 3. A convex portion 43 is formed between the concave portions 42 and 42 with a gap K of about 1 mm in the direction. The width of the concave portion 42 is about 300 μm, and the depth F is about 5 μm to 40 μm, preferably about 10 to 20 μm.

  The concave portion 42 may be formed by the machining. Further, in this example, since the concave portion 42 is formed in parallel with the length direction of the bearing hole 3, when the green compact 1A is pulled out from the core rod 13, the vertical protrusion of the core rod 13 and the concave of the green compact 1A. The part 42 does not interfere.

As described above, in the present reference example, since the fine uneven portion 41 is provided in the bearing hole 3 of the green compact 1A, the same operations and effects as the above-described embodiments are achieved.

FIGS. 11 and 12 show Embodiment 1 of the present invention. The same reference numerals are assigned to the same parts as those of the above-described reference examples, and detailed description thereof is omitted. In this example, the core rod 13 is This is a modification of the core rod side uneven portion provided on the outer peripheral surface 17 , and fine uneven portions 58 are formed on the outer periphery of the core rod 13 by electric discharge machining, and the fine uneven portions 58 are random uneven portions. By transferring the portion 58, a fine uneven portion is formed in the bearing hole 3 of the green compact 1A, and this fine uneven portion becomes a rough surface. Moreover, although the height of an uneven | corrugated | grooved part is random, it is preferable to set it as 5 micrometers-40 micrometers similarly to Example 1, and in this case, there may exist a part less than 5 micrometers.

As described above, in the present embodiment, the bearing hole 3 of the green compact 1A has the fine uneven portion and the core rod side uneven portion 58, so that the same operations and effects as the above-described reference examples are achieved.

Thus, in this embodiment, corresponding to claim 1, the raw material powder M is applied to the filling portion 16 formed between the molding die 12, the molding core rod 13 and the lower punch 14 of the molding die 11. The raw material powder M is filled with the upper punch 15 and the lower punch 14 to compress the green compact 1A having the bearing hole 3, and after the compression forming, the upper punch 15 is relatively used for the molding. Ascending above the die 12 and lowering the molding die 12 relative to the molding core rod 13 and the lower punch 14, the green compact 1A is discharged from the molding die 12 and discharged. In the manufacturing method of the sintered bearing which makes it possible to pull out the molding core rod 13 from the bearing hole 3 by the spring back of the green compact 1A, and sinter the green compact 1A. For EDM The raw powder M is compressed between the molding core rod 13 having a fine core rod side irregularity portion 18 that is formed in a random manner and the irregularity height is random, and the molding die 12 to compress the green compact. By forming the body 1A, the fine core rod side uneven portion 18 is transferred to the bearing hole 3 of the green compact 1A, and the fine uneven portion 4 is formed in the bearing hole 3 of the green compact 1A. Since the sintered bearing 1 is formed by sintering and the resin coating layer 5 is provided in the bearing hole 3 of the sintered bearing, a sintered body having fine uneven portions in the bearing hole can be manufactured. Moreover, the sintered bearing excellent in adhesiveness with a resin coating layer can be manufactured. Moreover, since the core rod side uneven portion is transferred to the green compact during compression molding of the green compact, machining or the like is not required for forming the concave and convex portion, and the production efficiency can be improved. Further, the green compact can be extracted from the core rod by utilizing the green back of the green compact, and fine irregularities can be formed in the bearing hole by a normal compression molding process.

Further, in this example, in correspondence with the second aspect, since the height of the uneven portion is 5 to 40 μm, the adhesion of the resin coating layer is excellent without impairing the extraction by the spring back. Sintered bearings can be manufactured.

In this way, in this example, in correspondence with claim 3, the height of the irregularities on the core rod side is 5 to 40 μm. Therefore, if the height is less than 5 μm, the irregularities of the sintered bearing Depth becomes small and the adhesion effect is not sufficiently obtained. On the other hand, if it exceeds 40 μm, there is a possibility that the extraction by the springback may be impaired, but by making it in the above range, it is suitable for production and excellent in adhesion. It will be a thing.
(Reference Example 5)

FIG. 13 shows a reference example 5 of the present invention. The same reference numerals are given to the same parts as those of the above reference examples, and detailed description thereof will be omitted. In this example, the outer peripheral surface 17 of the core rod 13 is shown in FIG. The fine irregularities 68 are formed on the outer periphery of the core rod 13, and the fine irregularities 68 are formed by the convex portion 19 having the triangular cross section and the concave portion 20 having the triangular triangle. The core rod 13 has a shape formed in a crossing direction with respect to the length direction. In the figure, the fine uneven portion 68 forms an angle of approximately 45 degrees with the length direction of the core rod 13.

As described above, in this reference example, the bearing hole 3 of the green compact 1A has a fine uneven portion and includes the core rod side uneven portion 68, so that the same operations and effects as the above reference examples are achieved.
(Reference Example 6)

FIG. 14 shows a reference example 6 of the present invention. The same reference numerals are given to the same parts as those of the above reference examples, and detailed description thereof will be omitted. In this example, the outer peripheral surface 17 of the core rod 13 is shown in FIG. The core rod side uneven portion provided on the outer periphery of the core rod 13 of Reference Example 6 in which the fine uneven portion 68 is formed is further formed with a fine uneven portion 78 that intersects the fine uneven portion 68. The concavo-convex portion 78 has a shape in which the convex portion 19 having a triangular cross section and the concave portion 20 having a triangular cross section are formed in a direction intersecting the length direction of the core rod 13. In the drawing, the fine uneven portion 78 forms an angle of approximately 45 degrees with the length direction of the core rod 13 in the direction opposite to the uneven portion 68.

As described above, in this reference example, the bearing hole 3 of the green compact 1A has fine uneven portions and the core rod side uneven portions 68 and 78, so that the same operations and effects as the above reference examples are achieved.

In addition, this invention is not limited to the said embodiment, A various deformation | transformation implementation is possible. For example, in Reference Example 1 and the like, an uneven portion having a circumferential groove-like recessed portion is shown, but a spiral shape may be used. Further, in Reference Examples 3 and 4, an example of an uneven portion having a wider convex portion than the concave portion is shown, but an uneven portion having a convex portion wider than the concave portion may be employed.

It is sectional drawing of the metal mold | die in the filling process which shows the reference example 1 of this invention. It is sectional drawing of the metal mold | die in a compression process same as the above. It is sectional drawing of the metal mold | die in an extraction process same as the above. FIG. 4 is a cross-sectional view of the molding die in the extraction process, showing a state where the green compact is discharged. It is an expanded sectional view of a core rod side uneven | corrugated | grooved part same as the above. It is sectional drawing of the sintered bearing which expanded a part same as the above. It is a perspective view of a compact and a processing tool which shows reference example 2 of the present invention. It is an expanded sectional view of the principal part of a processing tool same as the above. It is sectional drawing of the compact which shows the reference example 3 of this invention, FIG. 9 (A) is sectional drawing, FIG.9 (B) is an expanded sectional view of the principal part. It is sectional drawing of the compact which shows the reference example 4 of this invention, FIG. 10 (A) is sectional drawing, FIG.10 (B) is an enlarged plan view of the principal part. It is sectional drawing of the metal mold | die in the compression process which shows Example 1 of this invention. It is an expanded sectional view of a core rod side uneven | corrugated | grooved part same as the above. It is front explanatory drawing of the core rod which shows the reference example 5 of this invention. It is front explanatory drawing of the core rod which shows the reference example 6 of this invention.

DESCRIPTION OF SYMBOLS 1 Sintered bearing 1A Green compact 3 Bearing hole 4 Uneven part 5 Resin coating layer 11 Molding die 12 Molding die 13 Molding core rod 14 Lower punch 15 Upper punch 16 Filling part 17 Outer peripheral surface 18 Core rod side uneven part 31 Uneven part part 41 uneven portions 58,68,69, 78 core rod side uneven portion

Claims (3)

The raw material powder is filled in a filling portion formed between the molding die of the molding die, the core rod for molding, and the lower punch, and this raw material powder is pressurized by the upper punch and the lower punch to have a bearing hole. The powder is compression molded, and after the compression molding, the upper punch rises relatively above the molding die, and the molding die descends relative to the molding core rod and the lower punch. Thus, the green compact can be discharged from the molding die, and the green core can be pulled out of the bearing hole by the spring back of the green compact after being discharged, and the green compact is sintered. the method of manufacturing a sintered bearing comprising Te, formed by electric discharge machining on the outer peripheral surface, wherein the molding core rods height of each irregularity having a fine core rod side uneven portion is random, odor between the molding die By forming the green compact by compressing the raw powder, transferring the fine core rod side uneven portions in the bearing hole of the green compact, a bearing hole in the minute uneven portion of the powder compact A method of manufacturing a sintered bearing, comprising forming a sintered bearing by sintering after forming, and providing a resin coating layer in a bearing hole of the sintered bearing. Method for producing a sintered bearing according to claim 1, wherein a height of the uneven portion is 5 to 40 m. The method for manufacturing a sintered bearing according to claim 2, wherein the height of the irregularities on the core rod side is 5 to 40 μm.

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