WO1993007979A1

WO1993007979A1 - Method of making sintered metallic body and said body obtained through said method

Info

Publication number: WO1993007979A1
Application number: PCT/JP1992/001362
Authority: WO
Inventors: Akira Kimura; Yoshiyuki Katoh; Shigeru Wakoh
Original assignee: Pacific Metals Co., Ltd.; Thk Co., Ltd.
Priority date: 1991-10-21
Filing date: 1992-10-20
Publication date: 1993-04-29
Also published as: JPH0649511A

Abstract

A method of making a sintered metallic body, which comprises such processes that: metal powder and thermoplastic binder are mixed together at a determined rate into a compound to be subjected to injection molding through which a plurality of un-sintered segmentary parts are molded; said un-sintered segmentary parts thus obtained are assembled into an un-sintered assemblage in the shape of the final product and, prior to or subsequently to the assembling operation, subjected to degreasing treatment; the un-sintered assemblage is sintered with the shape of the final product kept unchanged; and a complete product composed of a metallurgically integrated sintered metallic body is obtained. The invention also consists in a side lid for the carriage of linear guide made by the above-described method and, further, in a method of making an impeller for liquid circulation.

Description

_tt

One 1 — Description

Method for producing metal sintered body and this

Technology obtained by the method

In the present invention, a metal powder and a thermoplastic binder are mixed at a predetermined ratio to prepare a compound, and a plurality of unsintered divided parts are formed by injection molding using the compound. The present invention relates to a method for manufacturing a metal sintered body in which a molded product is formed by using these unsintered divided parts to form a metal sintered body integrated on a metal structure, and such a method is used. The present invention relates to a side lid of a carriage used for a linear guide manufactured by the above method, and further relates to a method of manufacturing a liquid circulation impeller by such a method. Background technology

As a method of manufacturing a metal sintered body, generally, a thermoplastic binder such as a plex is added to a metal powder at a predetermined ratio, and the mixture is kneaded while heating to form a pellet. Such a compound is prepared, and a green compact of a predetermined shape is formed by press compression molding, injection molding, or the like using the compound, and the obtained green compact is formed. A method is employed in which the material is heated to perform a degreasing treatment for removing the binder, and then heated to a high temperature and sintered to obtain a metal sintered body having a desired shape.

In recent years, various excellent physical properties of metals, such as For example, in order to take advantage of stiffness, toughness, strength, elasticity, oil resistance, heat resistance, etc., it is required to manufacture various products with complicated shapes using metal. Attention has been focused on a method for producing a metal sintered body that can produce a desired shape using molding techniques such as compression molding and injection molding.

For example, in a linear guide that guides a movable body to be moved linearly in a machine tool such as an NC machine, an industrial robot, or a 0A device such as a copying machine or a printer, A ball endless track is formed on a carriage that reciprocates on the rail, and the load acting between the rail and the carriage is reciprocated by the ball rolling in the ball endless track. The load is movably loaded. For this reason, in such a linear guide, the side lids located on both end surfaces of the carriage change the rolling direction of the ball that has rolled linearly in the carriage body into approximately half. A circular ball turning path is formed to form an endless trajectory of the ball rolling in the carriage. In order to form such a ball endless track in the carriage, conventionally, the side lid of the carriage is provided with a synthetic resin end plate having a semicircular groove. A semi-disc-shaped synthetic resin round piece having a circumferential groove, the round piece is incorporated into the groove of the end plate, and the circumferential edge of the groove of the end plate and the circumferential groove of the round piece are formed. A substantially semi-circular ball-redirecting passage is formed with the side cover, and a substantially semi-circular ball-redirecting passage formed on the side cover and the carriage are formed. A ball endless trajectory is formed by a linear load ball guide path and a no-load ball guide path formed on the body side.

The side lid, which is composed of the end plate and the earpiece, is used to construct the carriage using this. In addition to the work of installing the ball, the work of assembling the round piece in the slot of the end bracket is required, and the work of assembling these balls and the round piece is complicated, which complicates the work of assembling the carriage. There was a problem. For this reason, it is conceivable to install a round piece in advance in the slot of the end plate for this side cover, but in this case, it is necessary to use the end plate when installing the ball. In order to prevent the arc pieces from dropping out of the slots, it is necessary to fix the end pieces and the round pieces in advance by means of an adhesive or the like. There was a problem.

Therefore, as a means for solving this problem, the present inventors have attempted to manufacture a side lid of a carriage used for a linear guide from a metal sintered body.

However, press compression molding requires pressurization from the upper and lower surfaces during molding, and is limited when the die is used. It is unsuitable when targeting a shaped product. In addition, in the case of injection molding, it is relatively easy to mold a three-dimensionally complex product. Since it is necessary to release the product, it is not easy to mold any shape, and the shape of the product that can be manufactured is naturally limited. For example, the side lid of the carriage used for the above linear guide also has a tunnel-like substantially semi-circular ball turning direction passage which forms a part of the ball endless track. Even if technology is applied, it is not possible to form the side lid in one injection molding.

Several methods have been proposed as means for overcoming such problems.

That is, U.S. Pat. No. 4,722,824 (Japanese Patent Application Laid-Open No. 62-289,378) discloses a first compound made of a conductive and sinterable metal powder and a binder. And a second green body are formed, and the first and second green bodies are placed in close contact with each other, and an electric current is applied between the first and second green bodies to form a green body. A method for producing a metal sintered body is disclosed, which comprises mixing the metal powders of both green bodies, joining the two together, removing a binder from the bonded green body, and then sintering. ing. However, in this method, the first green body and the second green body which are separately molded are integrated in the sintering process, but the first green body and the second green body which are closely adhered to each other are combined. In the energizing step of flowing a current between the unsintered bodies to mix and bond the metal powders of both unsintered bodies, an electric current is generated due to a contact state between the first and second unsintered bodies. As a result, after sintering, the joint surfaces of these unsintered bodies are not uniform on the metallographic structure. _r

Even if the first and second unsintered bodies are formed with high precision, it is not possible to strictly control the dimensional accuracy at the joint surface due to the uneven current flow.

Also, Japanese Patent Application Laid-Open No. 3-39,405 discloses that injection molding is performed by dividing a metal powder and a binder into a plurality of pieces using a compound composed of a binder and forming the same on the joining surfaces of these divided molded bodies. Production of a metal sintered body that consists of slurrying the metal powder of the composition with a liquid binder and attaching it, bonding each divided molded body by pressure bonding, removing the binder, and then sintering in vacuum. A method is disclosed. However, according to this method, even if the metal powder adhered to the joint surface of the divided molded body has the same composition, it is necessary to slurry this metal powder and adhere it. It is extremely difficult to make the density of the metal powder adhered to the joint surface in the metal powder application process to adhere the powder the same as the inside of the divided molded article and to make it uniform, and as a result, the thickness of the joint surface It is difficult to control the dimensions to a uniform and constant value, and after sintering, the joining surface of the two green bodies is not uniform on the metallographic structure.

For this reason, products used in precision machines that require particularly strict dimensional accuracy, and products that use heat such as frictional heat during use, such as the linear guide carriage described above, In the manufacture of the side lid, the dimensional accuracy of the manufactured metal sintered body cannot be accurately regulated due to dimensional errors generated in the energization process and the metal powder coating process, and the joint surface has a uniform metal structure. The failure to do so is fatal, and product yield Due to the problem of resilience and durability, US Pat. No. 4,722,824 (JP-A-62-289,378) discloses a method described in JP-A-3-39,405. Disclosure of the invention that cannot be applied as it is

Therefore, the present inventors have overcome such a problem, and have applied a manufacturing technology of a metal sintered body to a product having a complicated shape and high dimensional accuracy. For example, as a result of intensive research on manufacturing the side lids of carriages for linear guides and impellers for liquid circulation, etc., the joining surfaces of the divided parts formed by injection molding were directly joined. By sintering, the accuracy of the joint surface of the unsintered divided part formed by this injection molding is reflected as it is on the finished metal sintered body, and the metal structure is also joined. The present inventors have found that it is possible to obtain an integrated product that is the same as other parts except for the surface, and completed the present invention.

That is, according to the present invention, a metal powder and a thermoplastic binder are mixed at a predetermined ratio to prepare a compound, and a plurality of unsintered divided parts are formed by injection molding using the compound. It is molded, and the plurality of unsintered divided parts are combined as they are to assemble the unsintered assembly in the shape of the finished product. At this time, before or after assembling into the shape of the finished product, degreasing is performed. This is a method for manufacturing a metal sintered body that sinters a sintered assembly at a predetermined temperature while maintaining the shape of the completed product, and manufactures a finished product composed of a metal sintered body integrated on a metal structure. — One

Further, the present invention includes an end plate which is located on both end surfaces of a carriage constituting a linear guide, and an endpiece which is incorporated in the end plate. A side lid in which a substantially semicircular ball turning path of the ball endless track formed in the carriage is formed between the ball and the round piece, and is made of metal powder and a thermoplastic binder. The unsintered end plate formed by injection molding of the compound is combined with a round piece to form a side cover-shaped unsintered assembly having a substantially semicircular ball direction changing passage. The unsintered assembly thus assembled is degreased while maintaining its side lid shape, then sintered and manufactured, and the entire structure is formed of a single metal sintered body on a metallographic structure.Key is an arrow Li Tsu side lid di for the struggling de.

Further, in the present invention, a stainless steel powder obtained by a water atomization method and a thermoplastic binder are mixed at a predetermined ratio to prepare a compound, and the compound is used. The impeller body of the liquid circulation impeller and the trapping impeller are formed by injection molding, and the impeller-shaped green sintered assembly is assembled by combining the impeller body and the trapping impeller. At this time, before or after assembling into an impeller shape, degreasing is performed, and then the assembled unsintered assembly is sintered at a predetermined temperature while maintaining the impeller shape, and an integrated metal structure is formed. This is a method for manufacturing a liquid circulation impeller for manufacturing a finished product made of a metal sintered body.

The metal powder used in the present invention can be sintered Any suitable metal can be used. For example, su

Stainless steel powder such as S304L, SUS316L, SUS410L, SUS430L, SUS & 30 and high-speed steel powder such as SKH & 1, SKH57 , PB47, NO. — Magnetic alloy powders such as mendules, and non-ferrous metal powders composed of metals such as nickel, cobalt ', tungsten, titanium, etc. or alloys thereof.

These metal powders are usually pulverized by applying mechanical energy to the molten metal directly by, for example, centrifugal force or indirectly through a fluid such as water, oil, gas, or the like, and cooling the metal. It can be produced by the atomizing method, which solidifies to obtain a metal powder, the method of making metal powder from a metal lump by mechanical crushing, the crushing method, or the carbonyl method using a chemical reaction. Can be used, but various metal powders can be produced industrially at low cost, and the particle size is stable. More preferably, the shape of the produced metal powder is irregular, the bonding force between the metal powders is strong, and the strength of the produced molded body is high. The water atomization method using water is good. One

And, as for this metal powder, usually, those having an average particle diameter of 1 to 30 am and a maximum particle diameter of 70 // m or less are used, but injection molding is applied. After sintering, the joining surfaces of the plurality of divided parts need to be integrated on the metallographic structure, so the average grain size is preferably 1 to 30 ^ m and A large particle size of 20 μm or less is preferred. It is difficult to produce metal powder with an average particle size smaller than 1 m.

The thermoplastic binder used in the present invention only needs to be excellent in moldability and degreasing properties, and may be any of those conventionally used in this type of technology, such as wax, Polyvinyl butyral using ethyl alcohol as a solvent, acrylic resin and vinyl chloride resin using toluene as a solvent, vinyl chloride resin using butyl acetate as a solvent, and JP-A-1-301,805 And the like.The polyoxyethylene polyoxyl-opened pyrene condensate-based polyester described in (1) above as a main component is exemplified, and it is not particularly limited. Polyoxyethylene-polyoxypropylene condensate-based polyether is contained as a main component.

In the present invention, the compound used for the injection molding for molding the unsintered divided part is prepared by mixing the above metal powder and a thermoplastic binder at a predetermined ratio and kneading them. However, it is preferred that the obtained kneaded material is pelletized by an extruder or the like before use. The mixing ratio of the metal powder and the thermoplastic binder in preparing this compound varies depending on the product manufactured by this method, but generally the metal powder is 87 to 90%. 94% by weight, preferably 89-92% by weight, with the thermoplastic binder being 6-13% by weight, preferably 8-11% by weight. If the proportion of the thermoplastic binder is too small, there is a problem of molding failure, and if it is too large, there is another problem of poor binder removal. Using the compound thus prepared, a plurality of unsintered divided parts are formed by injection molding.

How to divide a finished product into a number of divided parts is appropriately designed depending on the target product, but each divided part is molded by injection molding. Therefore, it is preferable that the number of divided parts be as small as possible and have a shape that can be injection molded. For this reason, the side guide of the linear guide carriage, which is one object of the present invention, is divided into an end plate and a round piece incorporated in the end plate, and these are divided. It is better to mold it as a part. Also for other purposes

One of the liquid circulation impellers is preferably divided into an impeller main body having a main impeller and a catching impeller attached to the impeller main body, and these are formed as divided parts. .

Regarding the molding conditions for injection molding of such unsintered divided parts, since high dimensional accuracy is required for each divided part, it is necessary to mold at relatively low temperature and relatively high pressure. Typically, 50 to 200 ° C, preferably 500 to 150 ° C, at 500 to: L, 00 kg f / cmG, preferably 6 0 Tuesday to 9, which is a ^{0 0 kg f / cm 2 ·} G. If the injection temperature is lower than 50 ° C, there is a problem of poor plasticization in the molding machine, and if the temperature exceeds 220 ° C, there is a problem that the binder and the metal powder are separated. Further, the injection pressure is lower than 5 0 0 kg f / cnf · G occur problems that Takashi塡failure, also, 1, 0 0 0 kg f Z cm 2 · exceeds G multi Problems such as heavy burrs and poor mold release occur.

The unsintered divided parts formed in this way are assembled as follows to be assembled into a green body-shaped unsintered assembly. At this time, each divided part is subjected to a degreasing process. To remove the thermoplastic binder. The timing of the degreasing treatment may be before or after assembling the divided parts into one finished product, but may be performed after each divided part formed by injection molding. Since it is necessary to assemble into one finished product shape while maintaining the dimensional accuracy, it is preferable to perform a degreasing process after assembling the finished shape unsintered assembly. The method of the degreasing treatment is particularly limited as long as the thermoplastic binder in each divided part can be removed and the joining surface of each divided part can be eliminated at that time. Although not always, a method of circulating high-temperature air for a predetermined time or a method of extracting a solvent using a solvent such as water is employed, and a method of circulating high-temperature air is preferable. The processing conditions in this method of flowing high-temperature air are as follows: the thermoplastic binder in each divided part is efficiently removed, and at this time, the joint surface of each divided part is eliminated as much as possible to ensure uniformity. The temperature must be under normal pressure 100 ~ 600 ° C, preferably 300 ~ 400 ° C, more preferably 300 ~ 40 Air at 0 ° C is allowed to flow for 1 to 200 hours, preferably 40 to 70 hours. If the pressure during degreasing is too high or too low, problems such as poor degreasing will occur.If the temperature is lower than 100 ° C, the binder will remain. —— 丄 —— The problem arises. Furthermore, if the temperature exceeds 60 ° C., the structure of the degreasing furnace itself becomes large, which is economically disadvantageous.

The unsintered braid of the finished product shape assembled in this way is sintered at a predetermined temperature while maintaining the finished product shape, and the joining surface of each divided part disappears and the whole is made of gold. It is a finished product consisting of a metal sintered body that is integral with the metal structure. The sintering conditions at this time vary depending on the type of metal powder used, etc., but when an iron-based metal powder is used, it is usually from 1,100 to 1,450 °. C, preferably sintered at a temperature of 1,200 to 1,350 ° C for 2 to 6 hours. By this sintering, the joint surfaces of the divided parts completely disappear, and the whole is integrated in a metallic structure.

According to the present invention, each high-precision unsintered divided part obtained by injection-molding a compound composed of a metal powder and a thermoplastic binder is directly joined at its joint surface. As a result, the high dimensional accuracy of each divided part formed by injection molding can be used as it is, and as a result, the gap at the joint surface between each divided part generated at this joint surface can be The average particle size of the powder can be reduced to the average particle size or less, and after sintering, it is possible to obtain a finished product made of a metal sintered body in which the joint surfaces between the divided parts have completely disappeared. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 shows a linear guide provided with the side lid of the carriage manufactured in Example 1 of the present invention along the line I-I of FIG. _{1 G}

FIG.

FIG. 2 is a partial cross-sectional view showing the linear guide having the side cover of Example 1 along the line Π—Π of FIG.

F.3 is a partial cross-sectional view showing the linear guide having the side lid of Example 1 along the line HI-m of FIG.

FIG. 4 is a flowchart showing a manufacturing process for manufacturing a side lid of a linear guide carriage according to the first embodiment of the present invention.

Fig. 5 is a perspective view showing the unsintered end plate of the side cover prepared in Example 1.

FIG. 6 is a perspective view showing the green earth piece of the side cover manufactured in Example 1.

Fig. 7 shows the results when the unsintered assembly shown in Fig. 6 was set in the slot of the unsintered end plate shown in Fig. 5, and the unsintered assembly was assembled. FIG. 3 is a partial cross-sectional view showing a joined state between the end plate and the round piece in FIG.

Fig. 8 is an electron micrograph (magnification: × 1000) showing the distribution of metal particles inside the green end plate (or green RTP) obtained in Example 1. .

Fig. 9 is an electron micrograph (magnification: × 1000) showing the distribution of metal particles on the joint surface between the end plate and the round piece in the unsintered assembly obtained in Example 1. It is.

Figure 10 shows the unsintered assembly obtained in Example 1 at the joint surface between the endpiece and the round piece. FIG. 4 is an electron micrograph (× 1,000) showing the distribution of metal particles after degreasing.

Fig. 11 is an electron micrograph (magnification: × 1000) showing the metallographic structure at the joint surface between the end plate after sintering obtained in Example 1 and the round piece.

FIG. 12 is a front view showing the green impeller body obtained in Example 2 of the present invention.

Fig.13 is a perspective view of Fig.12.

FIG. 14 is a perspective view showing the green sintering trapping blade obtained in Example 2 of the present invention.

Fig.15 is a front view showing the impeller after sintering by attaching the trapping impeller of Fig.14 to the impeller body of Fig.12. BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be specifically described based on embodiments shown in the accompanying drawings.

Example 1

FIGS. 1 to 3 show a linear guide L having a side lid 1 of a carriage C according to a first embodiment of the present invention. The linear guide L is used for a linear motion slide section under a machine tool or an industrial robot. The linear guide L is formed in the carriage C, the rail R, and the carriage C. It is composed of a number of balls B circulating in the ball endless track 2 and applying a load between the carriage C and the rail. The carriage C has a load ball groove 3a for the ball B and a corresponding no-load ball hole 3b. ₁ _

It comprises a carriage body 3 and a pair of side lids 1 attached to both ends of the carriage body 3 and having a substantially semicircular ball direction changing passage 4. When these paired side covers 1 are attached to both ends of the carriage body 3, the linear load ball groove 3a and the no-load ball hole 3b of the carriage body 3 are formed. Are connected to both ends of a substantially semicircular ball direction changing passage 4 of each side cover 1, thereby forming a ball endless track 2.

In FIGS. 1 to 3, reference numeral 5 denotes a rolling groove of the ball B formed on the rail R side, reference numeral 6 denotes a grease nipple, reference numeral 7 denotes a side seal, Reference numeral 8 is an end seal.

The side cover 1 was integrally formed of a metal sintered body according to the method of the present invention, and was manufactured according to the following procedure.

(Preparation of metal powder)

Metal powder is prepared by a water atomization method in which high-pressure water is applied as mechanical energy to pulverize molten SUS304L stainless steel, and this is cooled and solidified to obtain metal powder. I went. The composition, particle size distribution, average particle size and maximum particle size of the obtained metal powder were measured. Table 1 shows the results. table 1

(Preparation of compound)

9.5% by weight of a binder having the composition shown in Table 2 was added to 90.5% by weight of the SUS 304 L powder prepared by the water atomization method prepared in this manner, and the mixture was kneaded. The mixture was kneaded at a temperature of 100 to 120 ° C. for 40 minutes, then pelletized by a pelletizer, and cooled with cold air to prepare a pellet-like compound.

Table 2

[Manufacture of side cover]

Using the pellet-shaped compound prepared as described above, follow the flow chart shown in Pig. , _

— 17— Manufactured.

That is, first, using the above-mentioned compound, an unsintered end plate 1a having the shape shown in Fig. 5 and a round piece 1b shown in Fig. 6 were formed by a metal injection molding machine. . With respect to the unsintered end plate 1a and the round piece 1b, the distribution state of the metal particles in the inside was observed with an electron microscope. Figure 8 shows the results.

Next, the end plate la and the round piece lb were removed by forcibly removing the casing formed during the injection molding, and the round piece lb was removed as shown in Fig. 7. It is fitted into the slot 9 formed in the end plate 1a and set, and the side cover-shaped unsintered assembly in which the end plate 1a and the round piece 1b are combined is assembled. Formed. At this time, the unsintered shape of the side lid assembled by the peripheral edge 10 of the slot 9 of the end plate la and the circumferential groove 11 of the round piece 1 b set in the slot 9 A substantially semicircular ball turning path 4 was formed in the assembly. In addition, the distribution state of the metal particles in the joint surface portion of the unsintered assembly was observed with an electron microscope. Figure 9 shows the results. As is clear from the micrograph shown in Fig. 9, the joint surface between the end plate 1a and the ball piece 1b of the unsintered assembly has almost the same size as the average particle size of the metal powder. It turned out that a gap had occurred.

The unsintered assembly in the shape of the side lid obtained in this way is charged into a degreasing furnace, where it is heated to 400 ° C under normal pressure and kept at this temperature for 48 hours. Degreased, and in the unsintered assembly ― The l-binder has been removed. By this degreasing treatment, more than 99% by weight of the binder in the unsintered assembly was removed. The distribution of the metal particles on the joint surface of the unsintered assembly after the degreasing treatment was observed with an electron microscope. The results are shown in FIG. As is clear from the micrograph shown in Fig. 10, the joint surface between end plate 1a and R-piece 1b observed in Fig. 9 disappeared completely, and the metal powder Was observed to be uniformly distributed throughout.

Next, the unsintered assembly with the side lid removed from the degreasing furnace was placed in a vacuum furnace, where it was heated at 1,250 ° C for 2 hours and vacuum-sintered. After the completion of the vacuum sintering process, the side cover 1 formed entirely of a metal sintered body was taken out of the vacuum path. With respect to the side cover 1, the metal structure of the unsintered solid body at the joint surface between the end plate 1a and the round piece 1b was observed with an electron microscope. The results are shown in FIG. As is evident from the micrograph shown in Fig. 11, the joining surface between the end plate 1a and the Rp 1b has completely disappeared, and the entire metal sintered body is integrated with the metal structure. It turned out that.

The side cover 1 made of a sintered metal body manufactured in this manner is then attached to both ends of the carriage body 3, and a large number of balls are placed in the ball endless track 2 formed at that time. Carrier C is assembled by incorporating B.

In the first embodiment, the side cover 1 has an end plate 1a and a round piece 1b integrally formed on a metal structure by a metal sintered body. _

The excellent dimensional accuracy when the piece 1b is manufactured by injection molding is directly reflected on the side cover 1 made of a sintered metal product, and the round piece 1b is used in the assembly process of the carriage C. Does not fall off the end plate 1a, so that its workability is greatly improved and it has excellent durability.

Example 2

Next, Figs. 12 to 15 show impellers for circulating a liquid for circulating a refrigerant used for cooling in an engine for an automobile or the like, and are manufactured by the method of the present invention. Oh

That is, in the same manner as in Example 1 above, SUS 3 16 having an average particle size of 9. and a maximum particle size of 30 zm by the water atomizing method was used.

L stainless steel powder was prepared, and 90 weight parts of the stainless steel powder was prepared from 5 weight% of a polyoxyalkylene-based polyether, 3 weight% of a natural wax and 2 weight% of a fatty acid. Then, 10 parts by weight of a binder was mixed, kneaded under the same conditions as in Example 1, and pelletized with a pelletizer to prepare a pellet-shaped compound.

Using the compound thus obtained, a blade having three main blades 13 as shown in Figs. 12 and 13 was formed using a metal injection molding machine in the same manner as in Example 1. the car body 12, _c then Let's were molded Do three catching the aid vanes 14 shown in Fig.14, three auxiliary vanes 14 molded in the earthenware pots this good, shown in Fig.15 Thus, it is installed between the main blades 13 of the impeller body 12 and inserted into the degreasing furnace, and heated at a rate of 10 ° CZ for 4 minutes. U

The temperature was raised to 00 ° C, and the temperature was maintained for 2 hours to perform a degreasing process, thereby forming a green sintered assembly having the same impeller shape as the finished product.

Next, the obtained unsintered assembly was placed in a vacuum sintering furnace, heated to 1,350 ° C at a heating rate of 80 ° CZ, and then kept at this temperature for 2 hours. And vacuum sintering.

In the manufactured impeller, the impeller body 12 and the three trapping blades 14 are a metal sintered body integrated on a metal structure, and the impeller body 12 and the three trapping blades 14 It had excellent strength at the joint surface. Industrial applicability

As is apparent from the results of the above examples, according to the method of the present invention, a product having a complicated shape and a high dimensional accuracy is required by applying the manufacturing technology of the metal sintered body. For example, the side lid of a carriage for linear guides, an impeller for liquid circulation, etc. can be easily manufactured, and the joining surface of each divided part formed by injection molding can be easily manufactured. By joining and sintering as it is, the accuracy of the joint surface of the unsintered divided part formed by this injection molding is reflected on the finished product of the metal sintered body as it is, a product with excellent dimensional accuracy In addition to the metallographic structure, it is possible to obtain an integrated product that is the same as other parts other than the joint surface. It can be improved.

In particular, the carrier for a linear guide manufactured by the method of the present invention. The side lid of the ridge has accurate dimensional accuracy, and the substantially semi-circular ball direction changing passage formed in the side lid is also accurately formed, so that the ball rolls smoothly and Is integrally formed of a metal sintered body, so that it is extremely easy to assemble it into a carriage.In addition, the entire structure is uniform in terms of metallography, and its durability, especially resistance to heat history Has excellent durability. Further, according to the method of manufacturing the impeller for liquid circulation of the present invention, the impeller body and the catching blade can be firmly connected to each other, and there is an auxiliary blade which was conventionally difficult to manufacture. As a result, an efficient and efficient liquid circulation impeller can be easily manufactured.

Claims

The scope of the claims

(1) A metal powder and a thermoplastic binder are mixed at a predetermined ratio to prepare a compound, and a plurality of unsintered divided parts are formed by injection molding using the compound. Combining these multiple unsintered split parts as they are

Assembling one finished product-shaped unsintered assembly, degreasing before or after assembling it into a finished product shape, and then maintaining the finished product shape for this assembled unsintered assembly. A method for manufacturing a metal sintered body characterized in that it is sintered at a predetermined temperature to manufacture a finished product composed of a metal sintered body integrated on a metal structure.

(2) The method for producing a metal sintered body according to claim 1, wherein the metal powder is produced by a water atomizing method.

(3) The metal powder according to claim 1, wherein the metal powder has an average particle diameter of 1 to 30 m and a maximum particle diameter of 70 am or less.

The method of manufacturing the aggregate.

(4) Combine multiple unsintered split parts into one complete

After assembling the unsintered assembly of the finished product, degreasing is performed.

A method for producing a metal sintered body according to claim 1.

(5) Combine each unsintered divided part to make the finished product

Unsintered split parts when assembling the unsintered assembly

The gap between the joining surfaces is less than the average particle size of the metal powder

Item 1. The method for producing a metal sintered body according to Item 1.

(6) Make up the linear guides.

As well as the end plate and the end plate.

These pieces are composed of A side lid in which a substantially semicircular ball redirection path of a ball endless track formed in a carriage between a unit and a round piece is formed by a metal powder and a thermoplastic binder. Combination of unsintered end plate formed by injection molding of a compound consisting of one and a round piece, and a side cover-shaped unsintered having a substantially semicircular ball direction changing passage The assembled body is assembled, degreased while maintaining the shape of the side lid of the assembled unsintered solid body, then sintered and manufactured, and the entire body is formed of an integrated metal sintered body on the metallographic structure. A side lid of a linear guide carriage that is characterized by

(7) The side lid of a carriage for a linear guide according to claim 6, wherein the metal powder is produced by a water atomization method.

(8) The side lid of a linear guide carriage according to claim 6, wherein the metal powder has an average particle diameter of 1 to 30 m and a maximum particle diameter of 70 / m or less.

(9) When the unsintered end plate formed by injection molding and the round piece are combined to assemble the side cover-shaped unsintered solid body, the end plate and the round piece are combined with each other. 7. The side lid of a linear guide carriage according to claim 6, wherein a gap between bonding surfaces between the guides is equal to or less than an average particle diameter of the metal powder.

(10) A stainless steel powder obtained by the water atomization method and a thermoplastic binder are mixed at a predetermined ratio to prepare a compound, and the compound is used for injection molding. By forming the impeller body and auxiliary blade of the impeller for liquid circulation, The impeller body and the auxiliary impeller are combined to assemble an impeller-shaped unsintered assembly, and before or after assembling into an impeller shape, a degreasing process is performed. The sintering assembly is sintered at a predetermined temperature while maintaining the shape of the impeller, thereby producing an impeller made of a metal sintered body integrated on a metal structure. Production method.