JPS6310066A - Manufacture of wear resistance sliding member - Google Patents

Abstract

PURPOSE:To obtain sliding part having a good quality and high accuracy by sticking a wear resistance sintered metallic powder sheet and a brazing filler metal powder sheet, which have blended a synthetic resin binder, respectively, sintering and filling it by a non-deposition heat resisting compacting mold, and installing it to a casting mold sliding part and casting it. CONSTITUTION:A synthetic resin binder to which an ethylene tetrafluoride resin emulsion and an acryl resin emulsion have been blended by an equal quantity is added by 3wt% to a prescribed quantity blended wear resistance sintered metallic powder which is mainly composed of a WC powder and a Cr3C2 powder, of a prescribed diameter, and they are kneaded and dried, and thereafter, a sheet of about 2mm thick is formed. Also, to an Ni self-fluxing alloy powder of a prescribed diameter, said binder is added by 3wt%, and they are kneaded and dried, and thereafter, a sheet of about 5mm thick is formed. Both these sheets are cut to a prescribed size, and these sheets S1, S2 are stuck by an acryl resin, put into a non-deposition heat resisting compacting mold 7 and burned in a vacuum, and formed to a prescribed shape by filling a sintering air-gap exhausted voltaile gas with a brazing filler metal. When this sintered sliding body 51 is installed to a casting mold and cast, a sliding surface 3 of a cam shaft 2 becomes a welded cam surface having high dimersion accuracy and being free from an air-gap, and the yield of a product is improved.

Description

Detailed Description of the Invention A6 Purpose of the Invention (1) Industrial Field of Application The present invention provides a wear-resistant sliding member, particularly a casting base material, on the outer periphery of the sliding part that is hollowed out using a mold. The present invention relates to a method of manufacturing a sliding body made of a wear-resistant sintered body that is integrally welded to the base material during casting.

(2) Conventional technology Conventionally, when manufacturing this type of member, a metal powder sheet made of wear-resistant sinterable metal powder and a synthetic resin binder is manufactured, and then the sliding part in the base material molding part of the mold is manufactured. Place the metal powder sheet in the mold facing the molding area,
Then, at the same time as pouring the metal into the base material forming part and casting the base material,
A sliding body obtained by sintering metal powder is welded to the outer periphery of a sliding part.

(3) Problems to be Solved by the Invention However, according to the above-mentioned method, the amount of molten metal in the sliding part forming area is small because the mold is used to hollow out the metal, and therefore it is difficult to obtain the amount of heat necessary to sinter the metal powder. may not be possible.

In addition, the metal powder sheet is attached to the mold using an adhesive, but since it contains synthetic resin, it is easily deformed by heat. There is a risk that the dimensional accuracy of the moving object may deteriorate, or the metal powder sheet may peel off from the mold, resulting in defective products.

Furthermore, the porosity of the sliding body increases due to thermal decomposition of the synthetic resin binder, so if high strength is required, infiltration treatment must be performed after casting, and the manufacturing man-hours and There is also the problem of increased costs.

In view of the above, the present invention improves the dimensional accuracy of the sliding body by compression molding a metal powder sheet into the shape of a sliding body and sintering it in the molded state, and also performs infiltration treatment at the same time in the sintering process. It is an object of the present invention to provide a manufacturing method that can reduce manufacturing man-hours and costs, and can also reliably weld a sliding body to the outer periphery of a sliding part at the same time as casting a base material.

B0 Structure of the Invention (11 Means for Solving the Problems) The present invention provides a method for solving the problems by adding a layer of metal powder to a part of the surface of a metal powder sheet made of wear-resistant sinterable metal powder and a synthetic resin binder.
A brazing powder sheet consisting of a brazing powder and a synthetic resin binder is bonded, and then compression molding is performed, which is non-adhesive to the metal powder and the melted brazing material in the sintering process, and has air permeability and heat resistance. a step of molding the metal powder sheet into the shape of the sliding body and making the brazing powder sheet follow the shape of the metal powder sheet; accommodating the metal powder sheet and the brazing powder sheet; placing the compression mold in a sintering furnace and sintering the metal powder at a temperature higher than the melting point of the brazing material to obtain the sliding body infiltrated with the brazing material; The sliding body is placed in the mold so as to face the sliding part molding area in the base material molding section, and then, the base material is cast by pouring molten metal into the base material molding section, and at the same time, the sliding body is placed in the sliding part. It is characterized by using a step of welding;

(2) Function Since the metal powder sheet is compression molded into the shape of a sliding body and the metal powder is sintered in the molded state, a sliding body with good dimensional accuracy can be obtained. Organic substances such as synthetic resin binders and adhesives are thermally decomposed and gasified during the sintering process, and the resulting gas is discharged through the pores of the compression mold, resulting in a sliding body free of defects caused by gas.

The porosity of the sliding body increases as the synthetic resin binder thermally decomposes, and the molten brazing filler metal infiltrates these pores by capillary action, resulting in simultaneous infiltration during the sintering process.

Furthermore, since the sliding body is made of a sintered body, even if the amount of molten metal in the sliding part molding area is small due to lightening with a mold, the sliding body can be reliably welded to the outer periphery of the sliding part at the same time as the base material is cast. .

Furthermore, the sliding body has good dimensional accuracy and does not deform during pouring, so the finishing time for the sliding body is shortened.

(3) Embodiment Figures 1 to 3 show a camshaft l for an internal combustion engine as a wear-resistant sliding member. It has a hollow hole of equal diameter over its entire length, and has a plurality of cam structure parts 3 as sliding parts arranged at predetermined intervals on the outer periphery and having an oval cross section. Cam surface portion 3 of each cam component 3
The outer peripheral surface of b is stepped so as to be lower than the base surface portion 3a by a predetermined height, and a thin U-shaped sliding body 51 made of a wear-resistant metal sintered body is attached to the stepped portion 4 of the camshaft. It is welded simultaneously with the casting of the main body 2. This sliding body5. A cam 6 is constituted by the cam structure portion 3 and a sliding body 5. The cam nose outer peripheral portion 6a is configured.

The camshaft body 2 is made of cast iron (for example, JISFC25,
FC30, etc.), cast steel (for example, JISSC46), etc.

Said sliding body5. is obtained from a metal powder sheet made of wear-resistant sinterable metal powder and a synthetic resin binder, and is infiltrated with a brazing filler metal.

Next, a method for manufacturing the camshaft 1 will be explained.

The metal powder sheet is manufactured through the following steps.

As a sinterable metal powder with wear resistance, WC powder with a diameter of 5 μm...50% by weight Cr, C, powder with a diameter of 15 μm...・40% by weight Mo powder with a diameter of 35 μm・・・・・・・・・・・・
...5% by weight WS with a diameter of 10 μm, powder...
・・・・・・・・・・・・5% by weight is mixed for 30 minutes using ■-blender. Next, as a synthetic resin binder, a 1:1 mixture of a tetrafluorinated ethylene resin emulsion and an acrylic resin emulsion is used. A synthetic resin binder is added to the metal powder in an amount of 3% by weight, and the mixture is kneaded using a kneader for 5 minutes. After drying the kneaded product at 100° C. for 30 minutes, it is passed through a roll machine to obtain a metal powder sheet with a thickness of 2 mm.

The brazing filler metal powder sheet is manufactured through the following steps.

The synthetic resin binder was added in an amount of 3% by weight to a Ni self-fusing alloy powder having a diameter of 30 μm as a brazing filler metal powder, and the mixture was kneaded for 5 minutes using a kneader.

After drying the kneaded product at 100° C. for 30 minutes, it is passed through a roll machine to obtain a brazing material powder sheet having a thickness of 5 mm.

4th. As shown in FIG. 5, the compression mold 7 is made of ceramic such as alumina, silicon nitride, silicon carbide, etc., and is non-adhesive to metal powder and molten brazing filler metal in the sintering process, and is breathable. resistant and heat resistant.

The compression mold 7 consists of an upper mold 7I and a lower mold 7t. A protrusion 8 having the same shape as the cam surface portion 3a of the cam component 3 is formed on the upper surface of the slider 5. A recess 9 defining a cavity having the same shape as the recess 9 and a concave arcuate groove 1o for molding a brazing material powder sheet formed on the arcuate inner surface of the recess 9 are provided.

As shown in FIG.
A brazing material powder sheet S2 having a length of 60n is adhered using an acrylic resin adhesive, and then a metal powder sheet Sl is attached to the entire convex arc surface 8a of the protrusion 8 in the lower mold 7□.

Place the upper mold 71 over the lower mold 7□, and fill the recess 9 with metal powder seam)S
The brazing material powder sheet St is fitted into the protrusion 8 having a
7. It fits into the concave arc groove 10 of.

Then, the upper mold 71 is replaced with the lower mold 7. When pressed, the metal powder sheet S is formed into the same shape as the sliding body 5I, and the brazing material powder sheet St follows the shape of the metal powder sheet SI.

The compression mold 7 containing the metal powder sheet Sl and the brazing material powder sheet S8 is placed in a vacuum sintering furnace, and under the heating-cooling conditions shown in FIG. Performs sintering of metal powder.

Heating zone A has primary to tertiary heating zones A, -A.

(1) Primary heating zone (Fig. 6 A) This heating zone A1 is approximately 650°C, and the heating time is 3
It is 0 minutes. In this heating zone A1, moisture first evaporates, and then the tetrafluoroethylene resin, acrylic resin, and acrylic resin adhesive in the synthetic resin binder are decomposed and gasified. The generated gas is discharged to the outside through the pores of the compression mold 7. The metal powder and brazing material powder are retained in the compression mold 7 even after the synthetic resin binder is decomposed.

(■) Secondary heating zone (Fig. 6 At) This heating zone A2 is approximately 900°C, and the heating time is 3
It is 0 minutes. In this heating zone A2, the metal powder is temporarily sintered. Further, undecomposed organic substances are completely gasified and discharged from the compression mold 7.

(■) Tertiary heating zone (FIG. 6A Riko's heating zone A) is approximately 1100° C. and heating time is 30 minutes.

In this heating zone A, the metal powder is sintered to obtain a thin U-shaped sliding body 51 shown in FIG. 7(al).

This sliding body 51 has a high porosity due to thermal decomposition of the synthetic resin binder, but in this tertiary heating zone A, a Nt self-fusing alloy (melting point: 1075-108
5°C) is melted, and the molten brazing filler metal is transferred to the sliding body 5. Since it enters the pores of the slide body 5I by capillary action, the sliding body 5I is subjected to infiltration treatment at the same time as sintering.

(rV) Cooling zone (Figure 7B) Furnace cooling is performed in this cooling zone B.

After the above sintering process, the compression mold 7 is taken out from the vacuum sintering furnace, the mold 7 is opened, and the slider 5. Release from the mold. A portion of the brazing material left on the surface of the sliding body 51 is easily removed by grinding or the like.

The sliding body thus obtained 5. Because it is sintered in a compression molded state, it has good dimensional accuracy and is also of excellent quality, with no defects caused by gases generated by decomposition of synthetic resin binders and the like.

By the same method as above, as shown in FIG. 7 (bl),
The sliding body 5 in the figure (al) is divided into two parts at the top to obtain a split-back sliding body 5□.Such a split-back sliding body 5□ is
It is obtained by applying the metal powder sheet SI to the convex arc surface 8a of the protrusion 8 in the lower die 7□ and then making a cut at the top thereof.

As shown in FIGS. 8 to 10, the mold M consists of a shell mold (main mold) 11 having an upper mold 111 and a lower mold 11g, and a round bar-shaped sand core 131 for forming a hollow hole. In the camshaft body molding cavity C as the base material molding part of the shell mold 11, each cam component molding area C, , Ct as the sliding part molding area is provided with a molding area facing the step part 4 of each cam component 3. Step part 12.
.

12! For example, in the left end of FIG. 8 and the third cam component molding area C3 from the left, a stepped portion 12 is located on the lower mold 11z as shown in FIG. The second and fourth cam component molding areas C! As shown in FIG. 10, the upper mold 11. and lower mold ll! Step part 12. is located.

As shown in FIG. 9, in each stepped portion 121 of the lower mold 11g,
Figure 7+al integrated sliding body 5. is pasted with an acrylic resin adhesive so as to face each cam component molding area C1.

In addition, the split-back sliding body 5t shown in FIG. 7(b) is attached to the stepped portion 12t spanning the upper and lower molds 11+ and 11g.
One sheet is placed in each section 11□ and adhered with acrylic resin adhesive in the same manner as described above, so as to face each cam component molding area C2. Each sliding body5. , 51 is the thickness of each stepped portion 12. ．． 12
! Since it is thicker than the depth of each sliding body 51, 5! is protruding from each step portion 121.12□.

Sand core 13. are arranged in the longitudinal direction of the cavity C, and the baseboard portions 13a at both ends thereof are the upper mold and the lower mold 11. .

It is held between 11□.

JTS Fe12 molten metal is injected into the cavity C through the sprue 14 at a casting temperature of 1350°C, and at the same time as the camshaft body 2 is cast, a sliding body 5+ is placed on the outer periphery of each cam component 3.
, 5g is welded. In this case, each cam component forming area C
,,Ct, the amount of molten metal decreases according to the volume of the sand core 131, but since each sliding body 58, 5 is made of a sintered body, even if the amount of heat is relatively small, each sliding body 53, 5□ is reliably welded to each cam component 3.

The acrylic resin adhesive is thermally divided by the molten metal, and the generated gas is discharged outside the mold through the countless continuous pores of the shell mold 11, so that no casting defects will occur in the camshaft body 2 due to the generated gas.

Further, the divided portions of the split-back type sliding body 5t are welded and integrated by the heat of the molten metal.

According to the method, the sliding body 5. ．． Since 51 is a sintered body and does not deform during pouring, the occurrence of defective products can be avoided as much as possible. Moreover, sliding body 51,5x
Since the dimensional accuracy of the camshaft body 2 is good and maintained even during casting of the camshaft body 2, the time required for finishing the sliding bodies 53, 5□ can be shortened.

FIG. 11 shows a case in which the thickness of the cam component 3 is formed to be approximately uniform and thin over the entire circumference, and such a cam component 3 is similar to the cam component 3 as shown in FIG. Molding area C
,,C, in that area CI+C! This is obtained by arranging the oval part 13b of the sand core 13□, which has a substantially similar shape. h' indicates a stepped hollow hole.

FIG. 13 shows an example of application of the full mold method, with a round bar-shaped sand core 13 similar to that shown in FIG. A styrofoam model 15 having the same shape as the camshaft body 2 is molded around the outer periphery of the camshaft body 2, and an oval part 15a corresponding to each cam component part 3 in the model 15 is formed.
An integrated sliding body 51 made of aluminum (FIG. 7) is adhered to the stepped portion 16 of the mold using an acrylic resin adhesive, and then the model 15 is buried in the shell mold 11'.

In this buried state, the model 15 corresponds to the cavity C, and therefore the oval part 15a corresponds to the cam component forming area C,
, C, so the sliding body 51 corresponds to the area C'+
, Cz.

During casting, the model 15 is thermally decomposed by the molten metal and replaced by the molten metal, and at the same time as the camshaft body 2 is cast, a sliding body 5. is welded. Further, the gas produced by thermal decomposition of the model 15 and the like is discharged outside the mold through countless continuous pores of the shell mold 11'.

Note that the present invention is applicable not only to camshafts but also to the manufacture of other sliding members. In addition, the brazing filler metal is Ag-based,
Common materials such as Cu-based materials are also used.

C0 Effects of the Invention According to the present invention, a metal powder sheet is compression molded into the shape of a sliding body, and sintering is performed in the molded state, so a sliding body with good dimensional accuracy can be obtained. Since the infiltration treatment is performed simultaneously in the process, the number of manufacturing steps and cost can be reduced compared to the case where the infiltration treatment is performed in a separate process.

Furthermore, since the sliding body made of a sintered body is used, even if the amount of molten metal in the sliding part molding area is small due to lightening with a mold, the sliding body can be reliably welded to the outer periphery of the sliding part at the same time as the base material is cast. Moreover, the dimensional accuracy of the sliding body is good.
Furthermore, since it does not deform during pouring, the finishing time for the sliding body can be shortened.

[Brief explanation of the drawing]

Figure 1 is a front view of the camshaft, Figure 2 is Figure 1 ■-■
3 is a perspective view of the main parts of the camshaft, FIG. 4 is an exploded perspective view of the compression mold, FIG. 5 is a longitudinal sectional view of the compression molding process, and FIG. 6 is a diagram showing the temperature and temperature during the sintering process. Graph showing the relationship with time, Figure 7 is a perspective view of the sliding body, Figure 8 is a vertical cross-sectional view of the mold, Figures 9 and 10 are line IX-IX in Figure 8, X-
X-ray cross-sectional view, Figure 11 is a longitudinal cross-sectional view of another camshaft,
Figure 12 shows the mold for casting the camshaft shown in Figure 11.
FIG. 13 is a longitudinal sectional view corresponding to FIG. 10 of a mold to which the full mold method is applied. C... Cavity as base material molding part, C+, C2.
・・Cam component molding area as sliding part molding area, M・
... Mold, S, ... Metal powder sheet, S2 ... Brazing material powder sheet, 2 ... Camshaft body as base material, 3 ... Cam component part as sliding part, 5 ．． ．． 5. ...Sliding body, 7.
... Compression mold, 15... Styrofoam model corresponding to the base material molding section, 15a... Egg-shaped part corresponding to the sliding part molding area Patent Applicant: Agent for Honda Motor Co., Ltd.
Ken Ochiai Patent Attorney

Claims (1)

[Claims] Manufacture a wear-resistant sliding member in which a sliding body made of a wear-resistant sintered body is integrally welded to the outer periphery of a sliding part of a casting base material that is hollowed out using a mold while the base material is being cast. In doing so,
A brazing powder sheet made of a brazing material powder and a synthetic resin binder is adhered to a part of the surface of a metal powder sheet made of a wear-resistant sinterable metal powder and a synthetic resin binder, and then the metal powder sheet in the sintering process is The metal powder sheet is molded into the shape of the sliding body using a compression molding die that is non-adhesive to the powder and the melted brazing material, and has air permeability and heat resistance. A step of imitating the shape of the metal powder sheet; installing the compression mold containing the metal powder sheet and the brazing material powder sheet in a sintering furnace, and heating the metal powder at a temperature higher than the melting point of the brazing material; obtaining the sliding body which has been sintered and infiltrated with the brazing material; installing the sliding body in the mold so as to face the sliding part molding area in the base material molding part of the mold; A method for producing a wear-resistant sliding member, comprising the steps of: pouring molten metal into the base material forming part to cast the base material, and at the same time welding the sliding body to the sliding part.