JPH0139696Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a joint structure in which a ceramic member and a metal member are combined to form a mechanical component used in a mechanical device, such as a rotating shaft.

Ceramic materials are suitable for mechanical parts constituting various mechanical devices that require wear resistance in high-temperature atmospheres.

However, ceramic materials have high hardness and wear resistance.
Although it has many excellent properties such as heat resistance and corrosion resistance, it has some difficulties in its workability, especially in its bondability with metal parts. Moreover, when the bonded parts are used in a high-temperature atmosphere or under conditions with severe temperature changes, the bond between the metal and ceramic parts separates due to the large difference in thermal expansion between the ceramic and metal parts. Because of this, it cannot be used as a mechanical component that transmits driving force especially in high-temperature atmospheres, and the reality is that it has not been widely used despite its excellent properties.

In order to solve this problem, a bonding structure as shown in FIG. 1 can be considered that absorbs the difference in thermal expansion between the metal and ceramic members and can withstand severe temperature changes. That is, a metal buffer W is bonded between a metal member M and a ceramic member C by brazing, friction welding, electron beam welding, etc., and a hole drilled in the center of the buffer W is inserted into the buffer W. They are joined by shrink fitting or brazing, but even with the buffer W in this way, there is still a difference in thermal expansion between the buffer W and the ceramic member C, so there is no tension in the axial direction. When a force is applied, regardless of whether the cross-sectional shape of the ceramic member C inserted into one end of the metal member M is circular or rectangular, the bonding strength of the ceramic member C is When we measured the pull-out strength, it was only about 17.5Kg/ ^mm2 at room temperature.
Furthermore, in high-temperature atmospheres of 300°C and 500°C, the pull-out strength deteriorates significantly to about 8.0 Kg/mm ² and 2.2 Kg/mm ² , respectively, and there is a risk that the ceramic member C may come off from the metal member M (buffer W). was large, and it was not possible to obtain mechanical parts with high reliability.

In view of the above-mentioned circumstances, this proposal is designed to prevent the ceramic member from slipping out of the metal member even when a tensile force in the axial direction is applied, since a minute gap is created between the metal member and the ceramic member based on the difference in thermal expansion. The purpose of the present invention is to provide a bonding structure that prevents this.

Hereinafter, embodiments of the present invention will be explained in detail with reference to the drawings.

In FIG. 2, 1 is a metal member, and the end of this metal member 1 has a recess 1a hollowed out in the axial direction.
is formed. Also, 2 is a ceramic member,
The end portion thereof has a tapered surface and a large diameter portion 2a that widens toward the end is formed. In addition, these metal members 1
The cross-sectional shapes of the recess 1a bored in the ceramic member 2 and the large diameter portion 2a of the ceramic member 2 are not limited to circular shapes.
It may be square or hexagonal, and is not particularly limited.

Therefore, the recess 1 formed at the end of the metal member 1
After the large-diameter portion 2a of the ceramic member 2 is inserted into the hole 1a, the tapered space formed between the surface of the large-diameter portion 2a and the inner wall surface of the recess 1a is filled in order to fix both members. Filled with hard solder material 3,
Metal member 1 and ceramic member 2 are joined together. Note that at this time, no metal layer or the like for brazing is formed on the surface of the large diameter portion 2a of the ceramic member 2, and the metal member 1 is tightly fitted due to thermal contraction after filling the hard solder material 3. Then both are fixed. As described above, since the joint structure is such that the large diameter part 2a of the ceramic member 2 is buried in the recess 1a of the metal member 1, the pull-out strength of the ceramic member 2 is measured to be 22.5 kg/mm ² at room temperature. The temperature is extremely high, even in high-temperature atmospheres of 300℃ to 500℃.
It has a pull-out strength of 17.8Kg/mm ² and 12.5Kg/mm ² , and will not come off even if a minute gap is created between the two members due to the difference in thermal expansion.

Further, as in the embodiment shown in FIG.
are joined in advance by brazing, shrink fitting, electron beam welding, etc., the large diameter part 2a of the ceramic member 2 is inserted into the internal space 4a of the buffer body 4, and the hard solder material 3 is inserted. By forming a filled bonding structure, it is possible to absorb more than the difference in thermal expansion between the two members and prevent separation due to pull-out. By the way, the pull-out strength in this example is at room temperature.
20.5Kg/mm ² , 14.6Kg/mm ² and 9.6Kg/mm ² in high temperature atmosphere of 300°C and 500°C, respectively.

Note that as the metal member 1, carbon steel, strong steel, heat-resistant stainless steel, etc., which are suitable for machine components, are used.

On the other hand, suitable materials for the ceramic member 2 include alumina ceramics and ceramics such as silicon nitride, silicon carbide, and zirconia, which have excellent thermal shock resistance, abrasion resistance, and flexural strength.

As mentioned above, the present invention has a joint structure in which the end of the ceramic member is inserted into a recess formed at one end of the metal member and fixed with hard brazing material.
Mechanical parts that are bonded in this way can completely prevent separation due to pull-out due to thermal expansion differences even when used in high-temperature atmospheres or in places with severe temperature changes, so the range of applications for mechanical devices is greatly expanded. It is possible to provide highly reliable mechanical parts for various industrial machines.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway cross-sectional view showing a conventional bonding structure between a ceramic member and a metal member, and FIGS. 2a and 2b are partially cutaway cross-sectional views showing a bonding structure between a ceramic member and a metal member according to an embodiment of the present invention. be. M, 1: Metal member, C, 2: Ceramic member,
W, 4: Buffer, 3: Hard wax material.

Claims (1)

[Scope of utility model registration request] An unexpanded tapered end formed on a ceramic member is inserted into a recess formed at the end of the metal member, and a gap is formed between the end surface of the ceramic member and the inner wall surface of the recess of the metal member. A bonding structure of a ceramic member and a metal member, characterized in that the formed tapered space is filled with a hard brazing material and fixed.