JPS5978983A - Ceramic and metal joint mechanism - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a bonding structure between ceramics and gold 1ift.

Bonding of ceramics and metals takes advantage of ceramics' excellent properties such as heat resistance, electrical insulation, and corrosion resistance.
It has been applied or is being applied to a wide range of areas including engine parts and electrical parts.

As a conventional bonding structure between ceramics and metal, the structure shown in FIGS. 1 and 2, for example, has been employed. Of these, FIG. 1 is a diagram showing a joining structure between a solid shaft-shaped ceramic l and a solid shaft-shaped metal 2, in which a sleeve 2a is formed on the solid shaft-shaped metal 2, and this sleeve 2a is heated to a high temperature. Solid axial ceramic l in a thermally expanded state
There are cases where they are fitted and joined by shrink fit.

Furthermore, in addition to the mechanical bonding shown in FIG. 1, FIG. 2 shows a structure in which a brazing material 3 is interposed between the sleeve 2a and the ceramic l to obtain chemical bonding.

In either case, a taper 2b is formed on the outer peripheral side of the end of the sleeve 2a so that the compressive stress from the metal sleeve 2a is applied to the ceramic 1 with a certain degree of gradient.

However, in such a conventional ceramic-metal joining structure, if only the shrink fit shown in Fig. 1 is used, the ceramic l and metal 2 In addition, there is a problem in that the dimensional accuracy of the sleeve 2a must be significantly improved, and when using the bracing shown in FIG. Because the size is increased, the dimensional viscosity is not as strict as in the case of only shrink fitting, but while the brazing filler metal is melting, the metal 2, such as the ceramic l, tends to move relative to each other, making the ceramic 1 and the gold II bar 2 more If they are not held accurately, there is a problem that the concentricity of the ceramic 1 and the metal 2 is likely to be lost after joining. Although it depends on the amount of sacrifice "9", if the wall thickness of the sleeve 2a is increased, the ceramic l may be destroyed, and on the other hand, if the wall thickness is decreased, the sleeve 2a may undergo plastic deformation. was.

This invention was made to solve the problems of conventional materials as described in -1-. LJ aims to provide a ceramic-metal bonding structure that does not cause any defects, does not require strict dimensional accuracy, and can obtain concentricity between the ceramic and metal with high precision.

This invention provides a bonding structure between ceramic, glue, and metal, in which a tapered conical protrusion is formed on the ceramic glue side, and a deep narrow circle 41 that fits into the circular groove on the metal side.
A recess is formed, and a recess for filling a brazing material is provided in one or both of the conical protrusion and the conical recess, and the conical protrusion and the conical recess are fitted and joined via the brazing material. It is characterized by

Ceramics to which this invention is applied include oxides such as alumina and zirconia, and silicon nitride.

Non-oxide materials such as boron nitride J's and silicon carbide are available, but they are not limited to 44'1- and can be applied over a wide range of materials. In addition, as for metals, iron-based or aluminum-based non-ferrous metals or alloys are applicable, and are not limited to 4. A wide range of materials can be used, from metals or resins with low melting points to those with high melting points.

Hereinafter, embodiments of this invention will be described in detail with reference to the drawings.

FIG. 3 is a diagram showing an embodiment of the present invention, in which a tapered conical protrusion 11a having a smaller diameter at the tip is formed at the joint side end of the shaft-shaped ceramic 11, and a shaft-shaped metal 11
A narrow circular recess 12a having substantially the same taper as the conical projection 11a is formed at the joining side end of the conical recess 12a, and a recess 12a for filling the brazing material is formed near the open end of the conical recess 12a. Part 4 12
It has a structure in which b is provided. In this case, the brazing filler metal filling recess 12b is formed over the entire circumference from the step part 12c to the opening end, and is formed with the conical protrusion 11a and the circle 9.
1i recessed part 12a is fitted, the stepped part 12
The part on the smaller diameter side than c ('is step part 12c in Figure 3)
The conical protrusion 11a and the circular 611 recess 12a are in direct contact with each other in the right side portion), and the brazing material filling recess 12b
A gap 13 for filling the brazing material is formed between the conical protrusion 11a and the conical protrusion 11a. Then, by interposing the solder J414 in the void 13 for filling the solder material, the ceramic 11
It has a structure in which the metal 12 and the metal 12 are joined together.

Note that a hollow hole 12d is formed in the metal 12, but this hollow hole 12d is used to prevent air trapped between the ceramic 11 and the metal 12 from expanding and causing an abnormally high internal pressure during brazing. This was created to prevent this.

Therefore, according to such a joining structure, the ceramic, tux 11 and metal 12 are bonded over a wide area with the brazing material 14 interposed.
Since the metal 12 has a wall thickness that gradually decreases toward the open end, the compression applied from the metal 12 to the ceramic 11 due to the difference in thermal expansion coefficient can be reduced. Stress is ceramics 1
Since the size gradually increases toward the tip of the conical protrusion 11a of No. 1, there is no fear of destruction of the ceramic 11 caused by sudden application of compressive stress, and mechanical damage at the base of the conical protrusion 12a with large compressive stress The bonding force also increases.

In addition, since the conical protrusion 11a and the conical recess 12a are directly fitted, the concentricity between the ceramic 11 and the metal 12 can be maintained with high accuracy without strict dimensional accuracy as long as the circularity is provided. (It has the advantage of being able to do things.

FIG. 4 is a view showing another embodiment of the present invention, and this embodiment shows a case where four brazing filler metal filling parts 11b are provided on the circular tlf protrusion 11a side of the ceramic 11.

In this case, the four parts llb for filling the brazing filler metal are formed over the entire circumference from the stepped part 11c to the large diameter side, and are shaped like a conical protrusion t"?1 (lla and the conical depression 12a fitted together).
In this case, the circle 31 toe protrusion 11a and the circle 311 recess 12a directly contact each other in the part on the smaller diameter side than the stepped part llc (the part on the right side of the stepped part 11C in FIG. 4), resulting in good concentricity. 411, and the brazing material is filled between the four brazing material filling parts 11b and the conical recessed part 12a.
! A filler gap 13 is formed, and by interposing a brazing filler metal 14 in the filler filler gap 13, the ceramic 11 and the metal 12 are bonded to each other with high strength.

Note that a gap 15 is formed between the end surface of the conical protrusion 11a and the bottom surface of the circular tIF recess 12a, so that the end surface of the ceramic 11 may be relatively rough.

In each of the above embodiments, the ceramic 11 and the brazing material 1
In order to improve the wettability between ceramics 1 and 4,
In some cases, it may be preferable to subject the brazing surface of Part 1 to a metallization treatment or the like. Further, it is also good to include an active metal in the brazing filler metal 14.

Furthermore, the ceramic product 11 and the metal 12 are not limited to having a shaft shape as a whole, and the ceramic product may have a conical protrusion.
1a, and a conical recess 12a is formed in the metal product,
The conical protrusion 11a and the conical depression 12a are brought into partial direct contact to achieve high joint size, precision, and degree, and the brazing material 14 is interposed in the void 13 for filling the wax which is not in direct contact. It is also possible to obtain high bonding strength by doing so.

Furthermore, in the embodiment, the brazing material filling recesses 11b, 1
2b are provided all around the circumference with the stepped portions 11c and 12c as boundaries, and as shown in FIG.
It is also possible to provide an axial protrusion s ++ l la at a distance of 100 mm, so that the concentricity of the ceramic 11 and the gold 15 bar 12 can be achieved with higher precision. At this time, even if the tip of the conical recess 12a of the metal 12 is deformed in a W-like manner toward the four filler filler parts 11b due to thermal contraction, it is clear that this will not affect the concentricity between the ceramic 11 and the metal 12. This structure can be applied to the four parts 12b for filling the cartilage material shown in FIG. 3 as well.

FIG. 6 is a diagram showing an example of application of the present invention, in which the invention is applied to joining a ceramic turbine rotor and a metal compressor impeller.

In this case, the ceramic turbine rotor 21 is integrally formed with the ceramic shaft 22, and the metal compressor impeller 23 is formed separately with the metal shaft 22.
4 is fixed.

And, at the joining side end of the ceramic shaft 22,
A conical protrusion 22a having a diameter of 9411 is formed. Further, the metal shaft 24 has a deep and narrow conical recess 24a that fits with the conical protrusion 22a at its joint end, and is filled with a brazing material near the open end of the conical recess 24a. Four parts 24b
is provided, and the other end side is formed into a small diameter shaft 24d, and this small diameter shaft 2
It has a structure in which a threaded portion 24e is provided at the end of the nd. Then, the small diameter shaft 24e is connected to the compressor impeller 23.
and fixed with a nut 26 through a washer 25.

In this way, the conical projection 22a and the conical recess 24a are fitted together, and good concentricity is obtained between the two members at the portion where the conical projection 22a and the conical recess 24a directly contact each other. By interposing the brazing filler metal 28 in the filler filler gap 27 formed between the recess 24b and the conical protrusion 22a, a high bonding strength of 1! I'll do what I do.

The thus obtained rotor-impeller assembly is then subjected to appropriate finishing processing, and the ceramic shaft 22 is supported by a floating bush type ceramic rotor side bearing 31, and the metal bridge 124 is also supported by a floating bush type ceramic rotor side bearing 31. It is supported by a type of metal impeller side bearing 32.

Therefore, by adopting such a joint structure, the concentricity of the turbine shaft is significantly improved, and compared to straight-shaped fittings, strict control of dimensional accuracy is not required, resulting in cost reduction. , it brings about advantages such as being able to increase the bonding strength by a layer compared to end face bonding.

pft, Fig. 7 is a diagram showing a modification of Fig. 6, in which the joint 81 of the ceramic acid @ I + 22 and the metal shaft 24 is set between the compressor impeller 23 and the impeller side 1111 + bridge 32. In this case, the diameter of the metal shaft 24 is made slightly smaller than the diameter of the ceramic casing 22.

In this way, the rotor side bearing 31 and the impeller side bearing 32 can be attached to the straight part of the ceramic housing 22 with M1.
Because I can ask you, both! 1-11 Jl'? Since the rotor can be moved, it has the advantage that the wear resistance is improved and at the same time, the temperature on the rotor side can be set higher.

In addition, in each of the embodiments and application examples described in J--, the brazing area can be increased by making the taper of the conical protrusion and the circular depression part gentler to increase the fitting length. It is possible to increase the chemical bonding force, and at the same time, it is possible to increase the mechanical bonding force caused by the difference in the coefficient of thermal expansion between the ceramic, metal, and brazing filler metal. Great bonding strength can be obtained.

As is clear from the above description, according to the present invention, in a ceramic-metal bonding structure, a tapered conical protrusion is formed on the ceramic side, and a deep part that fits into the conical protrusion is formed on the metal side. Forming a conical recess on the side,
Moreover, since the conical protrusion and the conical recess are provided with a recess for filling the brazing material in one or both of the conical protrusion and the conical recess, and the conical protrusion and the conical recess are fitted and joined via the brazing material, the conical protrusion The fitting part where the part and the conical recess are in direct contact makes it possible to improve the accuracy of the J-method joining between the ceramic and the metal, and to improve the concentricity of the joint between the shaft-shaped ceramic and the shaft-shaped metal. It is possible to improve the bonding strength between the ceramic and the metal by using the brazing filler metal interposed in the gap for filling the solder. It has many excellent effects, such as being able to prevent defects such as cracking and deformation in ceramics and gold W+.

[Brief explanation of the drawing]

1 and 2 are cross-sectional explanatory views showing conventional examples of bonding structures between ceramics and gold, and FIGS. 3 and 4 show bonding structures between ceramics and metal according to embodiments of the present invention. Cross-sectional explanations shown respectively (Figures 4 and 5 are cross-sectional explanatory diagrams taken at a position corresponding to the line V-V in Figure 4 according to other embodiments of the present invention, and Figures 6 and 7 respectively illustrate application examples of the present invention. It is a cross-sectional explanatory view of a turbine rotor and a compressor inlet and a bellows. 11...Ceramics, lla...Conical protrusion, 11
b... Concavity for filling brazing material, llc... Stepped part, 12
. . . Metal, 12a . . . Conical hollow portion, 12b . . . Gate portion for filling brazing material, 12c . Special 51 applicant: Patent attorney representing Nissan Motor Co., Ltd.
Yutaka Ko Shio

Claims (1)

[Claims] (1) A tapered conical protrusion is formed on the ceramic side, and a deep narrow conical recess that fits into the conical protrusion is formed on the metal side, and one or both of the conical protrusion and the conical recess are formed. 1. A bonding structure for ceramics and metal, characterized in that four parts for filling a brazing material are provided, and the conical protrusion and the conical depression are fitted and joined via a brazing material.