WO2014010429A1

WO2014010429A1 - Method for manufacturing thrust bearing for turbocharger, and thrust bearing for turbocharger

Info

Publication number: WO2014010429A1
Application number: PCT/JP2013/067638
Authority: WO
Inventors: 安央宮下; 喜浩酒井; 鈴木　隆
Original assignee: ナパック株式会社
Priority date: 2012-07-10
Filing date: 2013-06-27
Publication date: 2014-01-16

Abstract

Provided is a method for manufacturing a thrust bearing which actually can be used suitably in a turbocharger. This method has: a step wherein a first metal powder (17) is compression-molded into a tubular shape, thereby obtaining a compressed powder core material (18); a step wherein the compressed powder core material (18) and a second metal powder (27) different from the first metal powder (17) are supplied to the interior of a die (12); and a molding step wherein the second metal powder (27), is compression molded together with the compressed powder core material (18) within the die (12) by means of an upper punch (14) and a lower punch (15). The molding step is a step wherein protrusions formed on the upper punch (14) form an irregular shape which corresponds to the protrusions, said irregular shape being formed simultaneously with respect to the compressed powder core material (18) and the second metal powder (27), thereby forming a compressed powder compact (28) in which the compressed powder core material (18) and the second metal powder (27) are joined together. In addition, there is a sintering step wherein the compressed powder compact is heated and sintered, and a high-sliding part, which is the portion corresponding to the compressed powder core material (18) after the sintering step, has a better sliding property and abrasion resistance than an outer circumferential part, which is the portion corresponding to the second metal powder (27) after the sintering step.

Description

Manufacturing method of thrust bearing for turbocharger and thrust bearing for turbocharger

The present invention relates to a method for manufacturing a thrust bearing for a turbocharger and a thrust bearing for a turbocharger.

A step of forming an alloy powder mixture containing at least one of two elements of magnesium and aluminum as a main component, and at least one of boron, boron carbide, silicon carbide, aluminum oxide and silicon nitride is mixed with the alloy powder. Forming the composite material powder molded body by containing it in a part of the body, integrally molding the alloy powder mixture and the composite material powder molded body, and thereafter sintering the composite material molded body. There has been proposed a method for manufacturing a lightweight wear-resistant member (refer to claim 2, drawings, etc.) characterized in that the sintered part is formed so as to be used only for the sliding part (see Patent Document 1).

Japanese Patent Laid-Open No. 03-036231

However, thrust bearings for turbochargers are exposed to a wide temperature range (especially on the high temperature side), have a corrosive effect due to sulfur in the oil, are vibrated, and are subject to thrust loads. Have special characteristics that are used in difficult environments. On the other hand, Patent Document 1 assumes parts of products such as magnetic heads that are required to be light and thin, and is never used in an environment where a thrust bearing for a turbocharger is used. For this reason, a thrust bearing for a turbocharger is completely different from the lightweight wear-resistant member described in Patent Document 1 in terms of basic materials such as materials used and design concept.

Therefore, an object of the present invention is to provide a thrust bearing manufacturing method and a thrust bearing that can be suitably used in practice for turbochargers.

In order to achieve the above object, a method of manufacturing a thrust bearing for a turbocharger according to the present invention is characterized in that a first metal powder containing copper as a main component and containing 10 wt% or less of tin is formed around a cylindrical or cylindrical hole. A step of obtaining a powder core material by compacting into a shape obtained by cutting a part of the second metal powder and a second metal powder containing copper and containing iron of 80% by weight or less and the powder core material in a mold And a forming step in which both the second metal powder and the powder core material are compression-molded by a punch in a mold, and the forming step is such that the uneven surface formed on the punch is compressed An oil flow path having a shape corresponding to the uneven surface is formed on the core material and the second metal powder at the same time, and a powder compact formed by joining the powder core material and the second metal powder is formed. Process, and then has a sintering process in which the green compact is heated and sintered. The portion corresponding to the core material and the portion corresponding to the second metal powder after sintering are joined, and the portion corresponding to the powder core material after the sintering step is the second portion after the sintering step. It is superior in slidability and wear resistance than the portion corresponding to the metal powder.

In order to achieve the above object, a method of manufacturing a thrust bearing for a turbocharger according to the present invention is characterized in that a first metal powder containing copper as a main component and containing 10 wt% or less of tin is formed around a cylindrical or cylindrical hole. A step of obtaining a powder core material by compacting into a shape obtained by cutting a part of the second metal powder and a second metal powder containing copper and containing iron of 80% by weight or less and the powder core material in a mold And a step of compressing and molding the second metal powder together with the powder core material by a punch in a mold to obtain a powder compact, and heating and sintering the powder compact , A sintering step for obtaining a sintered body in which a portion corresponding to the powder core material and a portion corresponding to the second metal powder are joined, and a second die different from the die, and different from the punch A re-compression step of correcting the size of each part of the sintered body by the second punch, and the re-compression step The second uneven surface formed on the punch and the second mold is simultaneously applied to the portion corresponding to the powder core material after the sintering step and the portion corresponding to the second metal powder after the sintering step. It is a step of forming an oil passage having a shape corresponding to the second uneven surface, and a portion corresponding to the powder core material after the sintering step corresponds to the second metal powder after the sintering step. Better sliding and wear resistance than part.

Here, it is preferable to perform the forming step so that the powder density in the portion corresponding to the powder core material is higher than the powder density in the portion corresponding to the second metal powder.

Here, the uneven surface of the powder core material is preferably formed in both the step of obtaining the powder core material and the molding process.

In addition, when the shape of the dust core material is a shape obtained by cutting out a part of the periphery of the cylindrical hole, the positioning of the dust core material and the punch in the molding process is performed based on the shape of the cut portion. Preferably it is done.

Also, the oil flow paths formed in the dust core material and the second metal powder can be in communication with each other.

In order to achieve the above object, a thrust bearing for a turbocharger according to the present invention has a surface having a hole in the center on the front and back surfaces, and the edge of the hole on one surface is mainly composed of copper and has a weight of 10 wt. % Of tin, including a material imparting slidability and wear resistance, and a portion other than the edge portion is made of a metal material including copper and iron of 80% by weight or less, Parts other than the edge are joined, the edge is more slidable and wear-resistant than the part other than the edge, and the other part of the one surface is the oil flow path. Has a recess.

Here, it is preferable that the edge portion has a higher density than the portion other than the edge portion.

In the present invention, it is possible to provide a thrust bearing manufacturing method and a thrust bearing that can be suitably used for a turbocharger.

1 is a schematic plan view of a thrust bearing according to an embodiment of the present invention. It is a bottom face schematic diagram of a thrust bearing concerning an embodiment of the invention. FIG. 2 is a cross-sectional view taken along the line AA in FIG. It is a flowchart of the manufacturing process of the thrust bearing which concerns on embodiment of this invention. It is a longitudinal cross-sectional view of the core material manufacturing apparatus which shows a mode that manufacture of a powder core material progresses as it progresses from (A) to (D). It is a longitudinal cross-sectional view of the compacting body manufacturing apparatus which shows a mode that manufacture of a compacting body progresses as it progresses from (A) to (E). It is the schematic which shows the contact state of an upper punch and a compacting body in process P6. It is a figure which shows the manufacturing method of the modification of the thrust bearing which concerns on embodiment of this invention, and is a figure equivalent to FIG. It is a figure which shows the modification of the thrust bearing which concerns on embodiment of this invention similarly to FIG.

Hereinafter, a thrust bearing for a turbocharger (hereinafter abbreviated as “thrust bearing”) according to an embodiment of the present invention and a manufacturing method thereof will be described with reference to the drawings.

(Configuration of thrust bearing according to the embodiment of the present invention)
FIG. 1 is a schematic plan view (upper surface, one surface) of a thrust bearing 1 according to an embodiment of the present invention. This thrust bearing 1 is used in a turbocharger. The thrust bearing 1 has a circular outer periphery and a cylindrical shape having a circular hole 2 in the center. The thrust bearing 1 has an oil groove 3 that serves as an oil flow path around the hole 2. The thrust bearing 1 has four fixing holes 4 which are circular and have the same size and are equidistant to be fixed to the turbocharger. The edge portion of the hole 2 has a cylindrical shape and a high peristaltic portion 5 having a shape obtained by cutting out a part of the periphery of the cylindrical hole 2 and being more slidable and wear-resistant than other portions. (Part corresponding to the powder core material after the sintering step). A portion corresponding to a cut surface obtained by cutting a part of the periphery of the cylindrical hole 2 is a flat surface 5b. The upper surface of the high swing portion 5 is a surface that receives a thrust load. Here, let another part be the outer peripheral part 6 (part corresponded to the 2nd metal powder after a sintering process). Further, the high swinging portion 5 is formed with

grooves

7 a, 7 b, 7 c (the width dimension and the depth dimension are the same) which are oil flow paths as in the oil groove 3. Here, since the oil groove 3 and the

grooves

7a, 7b, and 7c are concave portions and the other portions are relatively convex portions, the upper surface of the thrust bearing 1 has an uneven portion. The high peristaltic part 5 has a higher density than the outer peripheral part 6.

FIG. 2 is a schematic diagram of the bottom surface (lower surface) of the thrust bearing 1. Although the hole 2 and the fixing hole 4 appear on the bottom surface of the thrust bearing 1, those corresponding to the oil groove 3 and the

grooves

7a, 7b, and 7c do not appear. The edge of the hole 2 is integrated with the outer peripheral portion 6.

FIG. 3 is a cross-sectional view taken along the line AA in FIG. The high peristaltic part 5 has a cylindrical shape and is exposed only on the plane side which is the upper side of FIG. Further, the upper surface 5 a of the high swing portion 5 is on the same plane as the upper surface 6 a of the outer peripheral portion 6.

Here, the outer peripheral portion 6 is a metal material composed of 37 parts by weight of copper, 60 parts by weight of iron, and 3 parts by weight of tin. Further, the high peristaltic part 5 is a metal material composed of 87 parts by weight of copper, 4 parts by weight of molybdenum disulfide, and 9 parts by weight of tin. Here, the mixing ratio of molybdenum disulfide is 4% by weight.

(Method of manufacturing a thrust bearing according to an embodiment of the present invention)
FIG. 4 is a flowchart of the manufacturing process of the thrust bearing 1. First, 87 parts by weight of electrolytic copper powder, 4 parts by weight of copper disulfide molybdenum disulfide, 9 parts by weight of atomized tin powder, and 0.5 parts by weight of zinc stearate serving as a wax take 10 to 30 minutes. Are mixed thoroughly and the first metal powder is blended (step P1). Here, the particle diameter of each powder was 1 to 200 μm suitable for powder metallurgy. The material imparting slidability and wear resistance in the first metal powder is copper bromide molybdenum disulfide.

The first metal powder is supplied into a mold, compressed and compacted to obtain a powder core material having a cylindrical shape and a part of the periphery of a cylindrical hole cut off (step) P2). FIG. 5 is a vertical cross-sectional view of the core material manufacturing apparatus 10 showing a state in which the production of the powder core material progresses from (A) to (D). As shown in FIG. 5A, the core material manufacturing apparatus 10 includes a table 11 and a die 12 that is a cylindrical mold. Here, the upper surface of the table 11 and the upper surface of the die 12 are on the same plane. The core material manufacturing apparatus 10 further includes a columnar core 13 in the die 12 in which the columnar space of the die 12 is cylindrical. The upper surface of the core 13 is flush with the upper surface of the table 11 and the upper surface of the die 12.

The core material manufacturing apparatus 10 is densely inserted into a space formed by the die 12 and the core 13 and having a cylindrical shape inside the die 12 and a part of the periphery of the cylindrical hole cut out. The upper punch 14 having a shape matching the shape inside the die 12 and the lower punch 15 having substantially the same shape as the upper punch 14 are provided. The upper punch 14 is provided with convex portions (not shown) for forming a part of the above-described

grooves

7a, 7b, 7c. A powder supply container 16 having a powder supply hole (not shown) on the lower surface is placed on the table 11. The powder supply device 16 is packed with a first metal powder 17. Further, the powder supply device 16 is movable on the upper surface of the table 11, the upper surface of the die 12, and the upper surface of the core 13.

In FIG. 5B, the powder supply device 16 moves, and the first metal powder 17 is transferred from the powder supply hole of the powder supply device 16 into the cylindrical space formed by the die 12 and the core 13. The supplied state is shown. The first metal powder 17 is supplied until the upper surface thereof is flush with the upper surface of the die 12 and the upper surface of the core 13.

5C, the upper punch 14 is moved in the arrow direction (from the upper side to the lower side) in the figure, and the lower punch 15 is moved in the arrow direction (from the lower side to the upper side) in the figure. It is a figure which shows the state which compression-molded the 1st metal powder 17 with the punch 14 and the lower punch 15. FIG. By this compression molding, a cylindrical powder core 18 is formed. The green compact density of the green powder core material 18 is set to an appropriate density that does not cause unintended shape deformation even if the green powder core material 18 is subjected to each step shown in FIG. The powder core 18 is formed with a concave shape corresponding to a part of the

grooves

7a, 7b, 7c described above (not shown). Moreover, the shape corresponding to the plane 5b mentioned above is formed in the powder core material 18 (illustration omitted).

In FIG. 5D, the upper surface of the lower punch 15 is moved in the direction indicated by the arrow (from the lower side to the upper side) until it is flush with the upper surface of the die 12 and the upper surface of the core 13, and compaction is performed. It is a figure which shows the state which made it easy to take out the core material.

Next, the second metal powder is blended (process P3). The second metal powder comprises 80 parts by weight of iron and copper partial diffusion alloy powder, 17 parts by weight of electrolytic copper powder, 3 parts by weight of atomized tin powder, and 0.8 part by weight of zinc stearate. Thoroughly mixed over 10 to 30 minutes. The iron content of the second metal powder is 60% by weight. The copper content of the second metal powder is 37% by weight. The tin content of the second metal powder is 3% by weight. Here, the particle diameter of each powder was 1 to 200 μm suitable for powder metallurgy. FIG. 6 is a vertical cross-sectional view of the green compact body manufacturing apparatus 20 showing a state in which the green compact manufacturing process proceeds from (A) to (E).

As shown in FIG. 6 (A), the green compact molded body manufacturing apparatus 20 includes a table 21 and a cylindrical die 22. Here, the upper surface of the table 21 and the upper surface of the die 22 are on the same plane. The compacted body manufacturing apparatus 20 further includes a columnar core 23 in the die 22 that has a cylindrical space in the die 22. The upper surface of the core 23 is flush with the upper surface of the table 21 and the upper surface of the die 22.

The compacted body manufacturing apparatus 20 has a cylindrical upper punch 24 and a cylindrical lower punch 25 which are inserted into a cylindrical space formed by the die 22 and the core 23 closely. A powder supply container 26 having a powder supply hole (not shown) on the lower surface is placed on the table 21. The powder supply device 26 is packed with a second metal powder 27. Further, the powder supply device 26 is movable on the upper surface of the table 21, the upper surface of the die 22, and the upper surface of the core 23. In addition, there is a flange portion (not shown) extending in a direction orthogonal to the length direction at the lower end portion in the length direction of the core 23 which is the vertical direction in FIG. 6, and extends from the flange portion in the length direction. There is a rod-like member (not shown). This rod-shaped member forms four fixing holes 4 as described later.

In FIG. 6B, the powder supply device 26 moves, and the second metal powder 27 is put into the cylindrical space formed by the die 22 and the core 23 from the powder supply hole of the powder supply device 26. The supplied state is shown. The second metal powder 27 is supplied until the upper surface thereof is flush with the upper surface of the die 22 and the upper surface of the core 23. This process becomes process P4. The rod-shaped member described above passes through a cylindrical space formed by the die 22 and the core 23. Therefore, the second metal powder 27 is not supplied to the space where the rod-shaped member is disposed. In addition, the 2nd metal powder 27 used 20 times the weight of the 1st metal powder 17 used for manufacture of the compacting core material 18.

FIG. 6 (C) is a view showing a state in which the powder core material 18 manufactured previously is embedded in the second metal powder 27 so as to expose the upper surface thereof, which is the peripheral surface of the core 23. is there. At this time, the portion corresponding to the flat surface 5b of the powder core 18 described above is recognized, and the portion corresponding to the flat surface 5b is in a predetermined positional relationship with a specific portion of the upper punch 24. The arrangement angle of 18 is adjusted. That is, the powder core material 18 and the upper punch 24 are aligned based on the shape of the flat surface 5b. By this alignment, the concave shape corresponding to a part of the above-described

grooves

7a, 7b, 7c formed when the powder core 18 is formed is further deformed by the convex portion 24b of the upper punch 24 described later. To be able to. The process of arranging the powder core 18 is a process P5.

6D, the upper punch 24 is moved in the arrow direction (from the upper side to the lower side) in the figure, the lower punch 25 is moved in the arrow direction (from the lower side to the upper side) in the figure, and the upper punch 24 is moved. It is a figure which shows the state which compression-molded the 2nd metal powder 27 with the lower punch 25 (process P6). By this compression molding, a cylindrical powder compact 28 is formed. Although not shown, the upper punch 24 and the lower punch 25 are formed with holes through which the above-described bar-shaped member is inserted, and the bar-shaped member is present in the second metal powder 27. P6 is performed. Therefore, the shape of the fixing hole 4 is formed at the position of the green compact 28 where the rod-shaped member exists. In the forming step, the compression force and the like are adjusted so that the powder density in the portion corresponding to the powder core material 18 is higher than the powder density in the portion corresponding to the second metal powder 27.

FIG. 7 is a schematic view showing a contact state between the upper punch 24 and the green compact 28 in the process P6. On the lower surface of the upper punch 24, a convex portion 24a that forms the shape of the oil groove 6 in the second metal powder 27 portion and a convex portion 24b that forms the shapes of the

grooves

7a, 7b, and 7c in the powder core material 18 are provided. Have. Portions other than the

convex portions

24a and 24b on the lower surface of the upper punch 24 are relatively concave portions. The concave shape corresponding to a part of the

grooves

7a, 7b, 7c of the powder core 18 is further deformed by the convex portion 24b.

In FIG. 6E, the upper surface of the lower punch 25 is moved in the direction of the arrow (from the lower side to the upper side) until it is flush with the upper surface of the die 22 and the upper surface of the core 23. It is a figure which shows the state which made it easy to take out the molded object. The green compact 28 has a cylindrical shape having the shape of the hole 1 at the center. The shape of the hole 1 is formed by the core 23. A dust core material 18 is arranged at the edge on the upper surface side in FIG.

Next, the green compact 28 is taken out, and the green compact 28 is sintered at a maximum temperature of 700 ° C. to 800 ° C. in an ammonia atmosphere (step P7). Then, the high peristaltic part 5 can have a higher density than the outer peripheral part 6. Thereafter, the sintered body that has undergone the process P7 is re-compressed using a mold and a punch in order to correct the dimensions of each part so as to have the target dimensions (process P8). Through the above steps, the manufacture of the thrust bearing 1 is completed.

(Main effects obtained by the embodiment of the present invention)
A thrust bearing 1 according to an embodiment of the present invention is a metal sintered body in which a high swing portion 5 and an outer peripheral portion 6 are joined. Therefore, the thrust bearing 1 is excellent in terms of strength, wear resistance, and the like, and can actually be suitably used for a turbocharger. In particular, the thrust bearing 1 used in the turbocharger has a thrust collar that restricts the movement of the impeller in sliding contact with and slides on the high sliding portion 5, so that the high sliding portion 5 has high wear resistance. The function of the bearing 1 is made necessary and sufficient. On the other hand, the metal material of the outer peripheral part 6 consists of the 2nd metal powder 27, and since content of iron is increased, the thrust bearing 1 can be made cheap.

The turbocharger thrust bearing 1 is exposed to a wide temperature range (particularly on the high temperature side), is affected by corrosion due to sulfur in the oil, is subjected to vibration, and receives a thrust load. There is a special feature used in harsh environments. However, according to the manufacturing method of the thrust bearing 1 which concerns on embodiment of this invention, the thrust bearing 1 which can endure such a severe environment can be provided. In particular, there is a concern about peeling due to corrosion or the like of the joint portion between the high swing portion 5 and the outer peripheral portion 6, but the thrust bearing 1 is unlikely to be peeled off and is in a joined state having sufficient joint strength and the like. is there.

Moreover, since the high peristaltic part 5 has a higher density than the outer peripheral part 6, the slidability and wear resistance of the high peristaltic part 5 are more excellent.

Further, portions corresponding to the

grooves

7a, 7b and 7c of the powder core material 18 are formed in both the step of obtaining the powder core material 18 and the molding step. Therefore, the amount of deformation of the dust core material 18 during the molding process can be reduced as compared with the case where the concave portions corresponding to the

grooves

7a, 7b, 7c are formed only by the molding process, and a phenomenon such as buckling can be suppressed. . In particular, since the powder core material 18 is subjected to the molding process in a high density state, the powder core material 18 is likely to buckle. Therefore, it is possible to form a shape corresponding to a recess at a position corresponding to the

grooves

7a, 7b, and 7c in the step of obtaining the powder core material 18, and to reduce the amount of change in the recess in the molding process. is important.

When the recesses corresponding to the

grooves

7a, 7b, and 7c are formed in both the step of obtaining the powder core material 18 and the molding step, the recesses are pressed by pressing the powder core material 18 in both steps. It is important that the positions to be formed are the same. Therefore, in the forming step, the recesses corresponding to the

grooves

7a, 7b, and 7c are formed by aligning the dust core 18 and the upper punch 24 with the shape corresponding to the flat surface 5b of the dust core 18 as a reference. The positions to be formed can be matched. In addition, by forming a shape corresponding to the flat surface 5b (a shape corresponding to a cut surface obtained by cutting off a part of the periphery of the cylindrical hole) in the dust core material 18, the high swinging portion 5 occupied by the thrust bearing 1 is obtained. Therefore, the thrust bearing 1 can be made cheaper.

Further, the thrust bearing 1 is cylindrical, and has a surface having a hole 2 shape at the center on the front and back sides, and a dust core material after the sintering step P7 on the edge of the hole 2 shape on one of the surfaces. The high peristaltic part 5 which is a part corresponding to 18 is arranged. Therefore, the edge of the hole 2 on the other surface opposite to the one surface receives the entire high swinging portion 5 that receives a thrust load. For this reason, even if the high vibration portion 5 receives a thrust load, it is difficult to apply the peeling stress to the joint portion between the high vibration portion 5 and the outer peripheral portion 6, but rather, the stress that makes the joint portion adhere is applied. The Rukoto. Therefore, the thrust bearing 1 which can reduce the above-mentioned peeling etc. can be provided.

A thrust bearing 1 according to an embodiment of the present invention is a cylindrical thrust bearing 1, and has a surface having a hole 2 in the center on the front and back surfaces, and one of the surfaces is a height that becomes an edge of the hole 2. The peristaltic part 5 is made of a material containing copper as a main component and imparts slidability and wear resistance. The outer peripheral part 6 other than the high peristaltic part 5 is 60% by weight with copper. The high-swing part 5 is more slidable and wear-resistant than the outer peripheral part 6, and the high-swing part 5 and the outer peripheral part 6 on one surface are grooves 7a. , 7b, 7c and oil groove 3 respectively.

Therefore, the edge of the hole 2 on the other surface opposite to the one surface receives the entire high swinging portion 5 that receives the thrust load. Therefore, even if the high vibration portion 5 is subjected to a thrust load, peeling stress is hardly applied to the joint portion between the high vibration portion 5 and the outer peripheral portion 6. Will be granted. Therefore, the thrust bearing 1 which can reduce the above-mentioned peeling etc. can be provided.

And in the process P6, the shape of the oil groove 3 and the

groove

7a, 7b, 7c is formed simultaneously with respect to the said press-contacting object, and the compacting body 17 is obtained. Therefore, compared with the case where the

grooves

7a, 7b, 7c formed in the high swing portion 5 and the oil groove 3 formed in the outer peripheral portion 6 are separately formed, the positional accuracy thereof can be improved. In particular, this positional accuracy is such that a passage such as a recess or a through hole is formed between the oil groove 3 of the outer peripheral portion 6 and the

grooves

7a, 7b, and 7c of the high swinging portion 5, and communicates with each other by the passage. It becomes very important when trying.

And in process P8 which is a recompression process after sintering, the shape dimensional accuracy of the

grooves

7a, 7b, 7c and the oil groove 3 can be improved at the same time.

(Other forms)
The method for manufacturing the thrust bearing 1 and the thrust bearing 1 according to the embodiment of the present invention described above are examples of the preferred embodiment of the present invention, but the present invention is not limited thereto and does not change the gist of the present invention. Various modifications can be made.

In the manufacturing method of the thrust bearing 1 according to the embodiment of the present invention, first, the first metal powder 17 is compacted into a cylindrical shape and a part of the periphery of the cylindrical hole is cut off. And a step P2 of obtaining a powder core material 18 in which a part of the

grooves

7a, 7b, 7c is formed in a concave shape. Then, the second metal powder 27 different from the first metal powder 17 and the powder core material 18 are set on the basis of the shape corresponding to the flat surface 5b of the powder core material 18, and the powder core material 18 and the upper punch. The process P4 and P5 which supply in the die | dye 12 are performed, performing 24 position alignment. And it has the shaping | molding process P6 which compression-molds the 2nd metal powder 27 by the upper punch 14 and the lower punch 15 in the die | dye 12 with the powder core material 18. FIG. In the molding step P6, the oil grooves 6 are formed such that the

convex portions

24a and 24b formed on the upper punch 14 correspond to the

convex portions

24a and 24b at the same time with respect to the powder core 18 and the second metal powder 27. And the shape of the

grooves

7a, 7b, 7c are formed, and the green compact 28 in which the green core material 18 and the second metal powder 27 are joined is formed. And it has the sintering process P7 which heats and compacts a compacting body. And the high peristaltic part 5 which is a part equivalent to the powder core material 18 after the sintering process P7 slides more than the outer peripheral part 6 which is a part corresponding to the second metal powder 27 after the sintering process P7. Excellent in mobility and wear resistance.

Here, in the method for manufacturing the thrust bearing 1 according to the embodiment of the present invention, the second metal powder 27, that is, the metal material of the outer peripheral portion 6, has a total iron content of 60% by weight. ing. However, in the case of a metal material containing copper, the metal material composition may be appropriately changed such that the iron content is 80% by weight or less, 70% by weight or less, 60% by weight or less, or 50% by weight or less. . If the iron content is increased, the cost of the thrust bearing 1 can be reduced. Further, the content of iron and tin can be made zero, and only electrolytic copper powder can be used as the metal component. If the iron content of the second metal powder 27 exceeds 80% by weight, the difference in shrinkage ratio during sintering with the first metal powder 17 is too large. There is a possibility that the bonding between the part 5 and the outer peripheral part 6 may be adversely affected.

Further, in the method for manufacturing the thrust bearing 1 according to the embodiment of the present invention, 4 parts by weight of cuprous molybdenum disulfide is included in the first metal powder. And the molybdenum disulfide compounding ratio of the high swing part 5 is 4 weight%. However, the molybdenum disulfide content ratio can be appropriately changed within a range of, for example, 1% by weight to 10% by weight. Further, in place of molybdenum disulfide, materials that impart slidability and wear resistance include manganese (such as manganese sulfide as a starting material), carbon materials such as graphite or pseudographite, lead, bismuth and tin. The metal material composition can be changed as appropriate, such as using an alloy, bismuth (the blending ratio is, for example, 1 to 10% by weight), iron sulfide, or the like. Moreover, instead of the partial diffusion alloy of copper and iron, each of the powders of copper and iron may be used as the second metal powder. However, if a partial diffusion alloy is used, it is difficult to segregate copper or iron during the sintering step (P7), so it is preferable to use a partial diffusion alloy.

Moreover, in the manufacturing method of the thrust bearing 1 which concerns on embodiment of this invention, the particle size of each powder of the 1st metal powder 17 and the 2nd metal powder 27 is 1 to 200 micrometers suitable for powder metallurgy. Using. However, the particle size of some or all of the powders constituting these may be outside the range of 1 to 200 μm, for example, 0.5 to 250 μm. Furthermore, the content of zinc stearate contained in the first metal powder and the second metal powder 14 can be changed as appropriate. In addition, zinc stearate can be replaced with other wax materials such as so-called amide wax, calcium stearate, lithium stearate and the like. Further, spindle oil may be added to the first metal powder 17 and the second metal powder 27. Furthermore, although the sintering step P7 is performed in an ammonia decomposition gas atmosphere, it may be performed in another reducing atmosphere such as a hydrogen atmosphere or an inert gas atmosphere such as a nitrogen atmosphere.

The second metal powder 27 used was 20 times the weight of the first metal powder 17 used in the production of the powder core 18. However, the usage amount of the second metal powder 27 can be in the range of 5 to 30 times that of the first metal powder 17. By increasing this multiple, the cost of the thrust bearing 1 can be reduced. In Step P5, the dust core material 18 is embedded in the second metal powder 27 so that the upper surface thereof is exposed and the upper surface of the dust core material 18 is not covered with the second metal powder 27. Arranged. However, in the process P5, the powder core material 18 is placed on the second metal powder 27, and the powder core material 18 is embedded in the second metal powder 27 in the next molding process P6. good. Further, in step P5, the dust core material 18 is partially embedded in the second metal powder 27, and in the next molding step P6, the dust core material 18 is placed in the second metal powder 27 as shown in FIG. As shown in FIG.

Further, the dust core material 18 is formed by compacting the first metal powder 17 into a cylindrical shape and by cutting off a part of the periphery of the cylindrical hole. However, such a shape is not necessarily required. For example, a cylindrical shape or the like may be used. The “tubular shape” includes a cylindrical shape, an elliptical cylindrical shape, a polygonal cylindrical shape, and the like. In addition, even if the powder core material 18 and the punch 24 are aligned in the molding process using a part of the shape of the powder core material 18 as a reference, the reference shape is other than the shape corresponding to the plane 5b. Various shapes can be adopted. For example, a recess is formed in a part of the upper surface 5a of the high sliding portion 5. The shape having such a dent is also a shape obtained by cutting out a part of the periphery of the cylindrical hole from the shape of the powder core material 18. Furthermore, it is good also as a shape which cut off a part of circumference | surroundings of a hole so that a part of inner peripheral surface of a cylindrical hole may be missing.

Further, the uneven surface formed on the powder core material 18 is formed by both the process of obtaining the powder core material 18 and the molding process. However, this uneven surface may be performed only in the step of obtaining the powder core 18 or only in the molding step. In the step of obtaining the dust core material 18, the first metal powder 17 is compression-molded. Therefore, changing the shape of the dust core material 18 in the subsequent formation step may cause buckling. Therefore, the uneven surface is preferably performed only in the step of obtaining the powder core material 18. The uneven surface may be formed by a recompression process other than the step of obtaining the powder core 18 and / or the molding step.

In addition, the oil flow paths formed in the dust core 18 and the second metal powder 27 are formed such that the passages of these oil flow paths are formed as depressions or through holes so as to communicate with each other. Also good.

Further, in the thrust bearing 1 according to the embodiment of the present invention, the high-density high-swing part 5 and the outer peripheral part 6 having a lower density than the high-sliding part 5 are made of a metal material containing copper. However, for example, a material having higher wear resistance such as brass or stainless steel can be used for the high swing portion 5. In that case, it is preferable to use a metal material containing the same metal as that of the high swing portion 5 for the outer peripheral portion 6.

Further, the thrust bearing 1 according to the embodiment of the present invention is configured such that the upper surface 5a of the high swing portion 5 is on the same plane as the upper surface 6a of the outer peripheral portion 6. However, for example, the upper surface 5 a of the high swing portion 5 may protrude from the upper surface 6 a of the outer peripheral portion 6, and conversely, the upper surface 6 a of the outer peripheral portion 6 protrudes from the upper surface 5 a of the high swing portion 5. Also good.

As shown in FIG. 7, the lower surface of the upper punch 24 has irregularities (irregular surfaces). As a similar configuration of the punch 24, the punch 24 may be divided into a plurality of punches having a dividing surface in the moving direction to form a multi-stage punch, and the same function as the formation of the concavo-convex portion may be performed. Similarly, the

lower punches

15 and 25 and the upper punch 14 can be multi-stage punches.

Moreover, although the density of the high peristaltic part 5 is made higher than the density of the outer peripheral part 6, the density of the high peristaltic part 5 and the density of the outer peripheral part 6 are made the same, or the density of the high peristaltic part 5 is made. You may make it lower than the density of the outer peripheral part 6. FIG.

Further, the oil groove 3 of the outer peripheral portion 6 and the

grooves

7a, 7b, 7c of the high swinging portion 5 are separated from each other, but a passage having a concave shape or a through-hole shape is formed and communicated with each other by the passage. Also good.

Further, the recompression process P8 may be omitted, for example, when the shape of the sintered body substantially matches the size of each part of the target thrust bearing 1 at the end of the sintering process P7. Further, the shapes of the oil groove 3 and the

grooves

7a, 7b, and 7c may be formed only in the recompression process P8 without being formed in the molding process P6.

Moreover, the following manufacturing methods are also employed in the steps P1 to P8 of the manufacturing method of the thrust bearing 1 according to the above-described embodiment of the present invention. The first metal powder 17 is compacted into a cylindrical shape to obtain a powder core 18, and the second metal powder 27 and the powder core 18 different from the first metal powder 17 are die-molded. Steps P4 and P5 to be fed into the inside 12 and a molding step P6 to obtain the compacted body 28 by compression-molding the second metal powder 27 together with the dust core 18 with the upper punch 14 and the lower punch 15 in the die 12. And a sintering step P7 for heating and compacting the green compact 28 to obtain a sintered body, and a second mold different from the die 12, and a second different from the upper punch 14 and the lower punch 15. A recompressing step of correcting the size of each part of the sintered body by using the punch, and the recompressing step includes a second uneven surface formed on the second punch and / or the second mold. The portion corresponding to the powder core 18 after the sintering step P7 and / or after the sintering step P7 2 is a step of simultaneously forming a shape corresponding to the second uneven surface with respect to the portion corresponding to the metal powder 27, and the portion corresponding to the powder core material 18 after the sintering step P7 is the sintering step P7. The slidability and wear resistance are superior to the portion corresponding to the second metal powder 27 later. The second concavo-convex surface forms convex portions 24a that form the shape of the oil grooves 6 shown in FIG. 7 in the second metal powder 27 portion, and the shapes of the

grooves

7a, 7b, and 7c in the powder core 18. It has the same shape as the convex part 24b and the convex part which performs the same function. In the recompression process P8, the dimensions of each part such as the shape of the oil groove 6 and the shapes of the

grooves

7a, 7b, and 7c, which have slightly changed in shape due to shrinkage or the like in the sintering process P7, are corrected.

Here, in the recompression process, the shape of both the oil groove 3 and the

grooves

7a, 7b, and 7c is corrected, but the shape of either the oil groove 3 or the

grooves

7a, 7b, and 7c is corrected. It's also good. For example, in FIGS. 2 and 7, the

grooves

7 a, 7 b, and 7 c are shallower than the oil groove 3. Therefore, the shape of the deep oil groove 3 can be formed in the molding process P6 that is easy to change in shape by a molding machine, and the

shallow grooves

7a, 7b, and 7c can be formed (corrected) in the recompression process. Moreover, although the 2nd uneven surface is formed in both the 2nd metal mold | die and the 2nd punch, it is good also as forming in either one.

Furthermore, in the molding process P6, it may be difficult to form a very large uneven shape. The reason for this is that if the shape change due to compression molding is large, there is a possibility of cracking later. In such a case, in the molding step P6, the shape is changed to such an extent that the objective is not reached (for example, 20 to 80% of the target), and finally the target uneven shape is obtained in the recompression step P8. And so on.

Further, the powder core 18 is manufactured as shown in FIG. 5 and has a cylindrical shape. However, the powder core 18 may have a plate shape, or may have a polygonal shape such as a quadrangle or a hexagon, or an elliptical cylindrical shape. This cylindrical shape may have a flat shape such as a 5-yen coin whose outermost diameter is much larger than the height. Moreover, although the powder core material 18 is obtained through the process P2, it is also possible to use what became a sintered body through the sintering process of only the powder core material 18 in the processes after the process P3. good. In that case, the sintering step of only the dust core material 18 may reduce the sintering temperature or reduce the sintering time to such an extent that the dust core material 18 is not completely sintered but partially sintered. It can be shortened. By doing so, while reinforcing the powder core material 18, it becomes easy to deform in the subsequent molding step P6. Furthermore, instead of the powder core material 18, a metal member having the same shape as the powder core material 18 may be used.

In the embodiment of the present invention, the step P6 of obtaining the powder core material 18 in which the first metal powder 17 is formed into a cylindrical shape and compression-molding the powder core material 18 and the second metal powder 27 together is performed. Provided. However, first, the second metal powder 27 is compacted into a shape similar to the shape of the outer peripheral portion 6 to obtain a powder core material, and then the powdered first metal powder 17 is removed from the high peristaltic portion 5. It is good also as obtaining the thrust bearing 1 through the process of supplying to a position and compressing together with the powder core material. Furthermore, both the first metal powder 17 and the second metal powder 27 may be compression-molded together in a powder state to obtain the thrust bearing 1.

Moreover, although the number of the fixing holes 4 is four, the number can be appropriately changed to two, three, five and the like. Moreover, the shape of the fixing hole 4 can be a part or all of a polygon such as a triangle or a rectangle, an ellipse, or the like. Further, the size of the fixing hole 4 can be changed in whole or in part. The number of the

grooves

7a, 7b, 7c is three, but the number can be appropriately changed to two, four, etc. Moreover, although the width dimension and the depth dimension of groove |

channel

7a, 7b, 7c are made equal, the width dimension and the depth dimension may differ in part or all. Moreover, although the holes 4 are provided at equal intervals, the holes 4 may be provided at not equal intervals. Further, the

grooves

7a, 7b, and 7c are provided not at regular intervals, but the

grooves

7a, 7b, and 7c may be provided at regular intervals.

Further, after the sintering step P7, a deburring step may be provided in which the thrust bearing 1 is vibrated in a large amount of ceramic spheres and water to remove burrs slightly present at the pointed portion of the thrust bearing 1. .

Further, the manufacturing method of the thrust bearing 1 according to the embodiment of the present invention may be changed. For example, FIG. 8 is a view showing a part of the manufacturing method of the modified example of the thrust bearing according to the embodiment of the present invention, and corresponds to FIG. In FIG. 8, the same members as those shown in FIG. 6 are denoted by the same reference numerals as those shown in FIG.

The difference between FIG. 8 and FIG. 6 is that, first, a powder core material 31 having a height corresponding to the powder core material 18 higher than that of the powder core material 18 is arranged in the die 12, and then the powder core material 31 The second metal powder 27 is supplied to the outer peripheral surface side. Other steps are the same as those shown in FIG. According to the manufacturing method according to this modification, the thrust bearing 32 in which the dust core material 31 is exposed on the upper and lower surfaces of the drawing is produced. In the thrust bearing 32 having this configuration, it is considered that the thrust load received by the high swing portion 5 tends to concentrate on the joint surface between the high swing portion 5 and the outer peripheral portion 6. In this regard, the thrust bearing 1 that has undergone the manufacturing method shown in FIG. 6 has a high thrust load because the edge of the hole 2 on the bottom surface is integrated with the outer peripheral portion 6 as shown in FIGS. It can be received via the peristaltic part 5. Therefore, the degree to which the thrust load is concentrated on the interface between the high swing portion 5 and the outer peripheral portion 6 is low, and a more stable thrust bearing 1 can be provided.

When the state shown in FIG. 8C is changed to the state shown in FIG. 8D, that is, when the powder core material 31 and the second metal powder 27 are compression-molded together, The thickness of the powder core material 31 in the horizontal direction in the figure can be slightly increased (shown as the same thickness in FIGS. 8C and 8D). If the green compact density of the green compact 31 is sufficiently high, the change in the thickness will be large, and if the green compact density of the green compact 31 is low, the change in the thickness will be small.

Further, in the method of manufacturing the thrust bearing 1 according to the embodiment of the present invention, as shown in FIG. 6, the second metal powder 27 is first supplied into the die 12 and then the powder core material 18 is disposed. Yes. Further, the lower surface of the upper punch 24 has

convex portions

24 a and 24 b. However, in the manufacturing method of the thrust bearing 1 according to the embodiment of the present invention, first, the dust core material 18 is disposed on the upper surface of the lower punch 15 in the die 12, and then the second metal powder 27 is applied to the lower punch 15. The upper surface may be supplied on the dust core material 18. In that case, the lower surface of the upper punch 24 does not have the

convex portions

24a and 24b, and the upper surface of the lower punch 15 has convex portions that function in the same manner as the

convex portions

24a and 24b of the lower surface of the upper punch 24 shown in FIG. Will be formed. In this manufacturing method, when the dust core material 18 is arranged on the upper surface of the lower punch 15, it is considered that the impact given to the dust core material 18 is large. The method is preferred. In the manufacturing method shown in FIG. 6, the second metal powder 27 functions as a cushion when the powder core 18 is disposed.

The manufacturing method of the thrust bearing 1 according to the embodiment of the present invention is shown in FIG. 4, FIG. 5 and FIG. A manufacturing method in which the powder core 18 and the second metal powder 27 are compression-molded together after the powder core 18 is formed is not limited to the product field of thrust bearings, and uses powder metallurgy. It can be applied to other product areas.

FIG. 9 is a view showing a thrust bearing 41 of a modification of the thrust bearing 1 according to the embodiment of the present invention in the same manner as FIG. In FIG. 9, members similar to those shown in FIG. 1 are given the same reference numerals as those shown in FIG. 1, and descriptions thereof are omitted. The thrust bearing 41 has a shape in which about a quarter of the left side in FIG. The high-sliding portion 5 of the thrust bearing 41 is compacted into a shape in which a part of the periphery of the hole is cut out so that a part of the inner peripheral surface of the cylindrical hole is missing, Manufactured similarly. The powder core material having such a shape also has a shape obtained by cutting off a part of the periphery of the cylindrical hole. Other members such as the outer peripheral portion 6 are manufactured in the same manner as the thrust bearing 1 or the thrust bearing 32.

1, 32, 41 Thrust bearing 2 holes 3 Oil groove (uneven portion)
5 High peristaltic part (corresponding to the dust core material after the sintering process)
5b Plane (shape obtained by cutting off a part of the periphery of the cylindrical hole)
6 Peripheral part (part corresponding to the second metal powder after the sintering process)
7a, 7b, 7c Groove (uneven portion)
12 dies
18, 31 Powder core 24 Upper punch (punch)
25 Lower punch
28 Powder compact body P2 Obtaining a powder core material P4 Process for supplying the second metal powder into the mold P6 Molding process (process for forming the compact body)
P7 Sintering process P8 Recompression process

Claims

In the manufacturing method of thrust bearings for turbochargers,
A step of compacting a first metal powder containing copper as a main component and having a tin content of 10% by weight or less into a shape obtained by cutting a part of the periphery of a cylindrical or cylindrical hole to obtain a powder core material; ,
Supplying a second metal powder containing copper and having an iron content of 80% by weight or less and the powder core material into the mold;
A molding step in which both the second metal powder and the powder core material are compression-molded with a punch in the mold,
In the molding step, the uneven surface formed on the punch forms an oil passage having a shape corresponding to the uneven surface simultaneously with respect to the powder core material and the second metal powder. A step of forming a green compact formed by bonding the powder core material and the second metal powder,
And then having a sintering step of heating and sintering the green compact,
A portion corresponding to the powder core material after sintering and a portion corresponding to the second metal powder after sintering are joined,
The turbocharger is characterized in that the portion corresponding to the dust core material after the sintering step is more slidable and wear resistant than the portion corresponding to the second metal powder after the sintering step. A method for manufacturing thrust bearings for chargers.
In the manufacturing method of thrust bearings for turbochargers,
A step of compacting a first metal powder containing copper as a main component and having a tin content of 10% by weight or less into a shape obtained by cutting a part of the periphery of a cylindrical or cylindrical hole to obtain a powder core material; ,
Supplying a second metal powder containing copper and having an iron content of 80% by weight or less and the powder core material into the mold;
A molding step of compressing the second metal powder together with the powder core material with a punch in the mold to obtain a powder compact,
A sintering step of heating and sintering the green compact, and obtaining a sintered body in which a portion corresponding to the powder core and a portion corresponding to the second metal powder are joined,
Using a second mold different from the mold, and a recompressing step of correcting the size of each part of the sintered body with a second punch different from the punch,
In the recompression process, the second uneven surface formed on the second punch and the second mold is a portion corresponding to the powder core material after the sintering process and after the sintering process. Forming a flow path of oil having a shape corresponding to the second concavo-convex surface at the same time for a portion corresponding to the second metal powder.
The turbocharger is characterized in that the portion corresponding to the dust core material after the sintering step is more slidable and wear resistant than the portion corresponding to the second metal powder after the sintering step. A method for manufacturing thrust bearings for chargers.
In the manufacturing method of the thrust bearing for turbochargers of Claim 1 or 2,
The turbocharger thrust characterized in that the forming step is performed such that a powder density in a portion corresponding to the powder core material is higher than a powder density in a portion corresponding to the second metal powder. Manufacturing method for bearings.
In the manufacturing method of the thrust bearing for turbochargers of any one of Claim 1 to 3,
The method for producing a thrust bearing for a turbocharger, wherein the uneven surface of the powder core material is formed by both the step of obtaining the powder core material and the molding step.
In the manufacturing method of the thrust bearing for turbochargers of Claim 4,
When the shape of the powder core material is a shape obtained by cutting out a part of the periphery of a cylindrical hole, the position of the powder core material and the punch in the molding step on the basis of the shape of the cut portion A method of manufacturing a thrust bearing for a turbocharger, characterized by performing matching.
In the manufacturing method of the thrust bearing for turbochargers of any one of Claim 1 to 5,
A method of manufacturing a thrust bearing for a turbocharger, characterized in that oil flow paths respectively formed in the powder core material and the second metal powder communicate with each other.
A thrust bearing for a turbocharger,
It has a surface with a hole in the center on the front and back, and the edge of the hole on one of the surfaces has copper as the main component and 10 wt% or less of tin, giving slidability and wear resistance Containing materials to
The part other than the edge part is made of a metal material containing copper and iron of 80% by weight or less,
Parts other than the edge and the edge are joined,
The edge is more slidable and wear-resistant than parts other than the edge,
A thrust bearing for a turbocharger, wherein each of the one surface has a recess that serves as an oil flow path.
The thrust bearing for a turbocharger according to claim 7,
A thrust bearing for a turbocharger, wherein the edge portion has a higher density than portions other than the edge portion.