JPH03275574A - Method for coupling ceramics member and metallic member - Google Patents

Abstract

PURPOSE:To improve coupling strength by inserting a round bar-shaped ceramics member having an annular groove into a hollow cylindrical metallic member and repeating cooling and heating from the outside to cause the plastic deformation of the metallic member, and thereby coupling this member to the ceramics member. CONSTITUTION:The bar-shaped ceramics member 2 made of Si3N4, etc., provided with the shallow annular groove is inserted into one end of the hollow cylindrical metallic member 1 consisting of a stainless steel, etc. A part (a) of the metallic member 1 is then subjected to the repetition of the cooling and the heating by cooling water nozzles 3 and a high-frequency heating coil 5 and is successively moved in a low-temp. region 6 and a high-temp. region 7 along the axial direction. The plastic deformation of shrinkage is generated in the ceramics enclosing part 1a of the metallic member 1. This part tightens the ceramics member 2 when the part restores to room temp. In addition, the part 1c of the metallic member 1 on the outer side of the annular groove 8 of the ceramics member 2 is intruded into the annular groove 8 by the plastic deformation of the shrinkage. The ceramics member 2 and the metallic member 1 are thus more securely coupled. The pull-out of the two members hardly arises.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method of joining ceramic members and metal members, and is particularly applicable to rotating shafts in turbo machines such as centrifugal blowers and superchargers.

Conventional turbomachines are known to use ceramic rotating shafts, but generally the ceramic rotating shaft is coupled to a metal rotating shaft and torque is applied to the metal rotating shaft. Many rotational configurations are used.

Conventionally, a shrink fit method has been used to connect such a ceramic rotating shaft and a metal rotating shaft, as shown in FIGS. 3 and 4.

That is, as shown in FIG. 3, first, a hollow cylindrical metal member 1 constituting a metal rotating shaft is heated to a high temperature by an appropriate heating device, and the metal member 1 heated to this high temperature is heated to a high temperature.
A round rod-shaped ceramic member 2 constituting a ceramic rotating shaft is inserted into one end of the rotary shaft.

As shown in FIG. 4, when the metal member 1 returns to room temperature, the inner diameter of the metal member 1 before heating becomes smaller than the outer diameter of the ceramic member 2. Although the portion 1b of the metal member 1 that does not surround the ceramic member 2 can return to its original size,
Since the portion 1a of the metal member 1 surrounding the metal member 1 cannot return to its original size, the ceramic member 2 is tightened. This tightening causes the ceramic member 2 and the metal member 1 to be joined together by force.

In such a conventional shrink fitting method, in order to obtain an appropriate tightening force for the ceramic member 2, it is necessary to appropriately select the dimensions of the metal member 1 and the heating temperature. Therefore, it was necessary to pay close attention to the dimensions of the metal member 1. In particular, when the metal member 1 is a hollow cylindrical rotating shaft with a small diameter,
This requires a diameter accuracy of 1/1000a++n or more, which may be difficult to implement due to processing accuracy.

Further, heating time is required to bring the metal member 1 into a uniform high temperature state, and depending on the heating temperature and time, scale may occur on the inner surface of the metal member 1, making shrink fitting difficult.

Further, the work of inserting the ceramic member 2 into the high-temperature metal member 1 has a problem that the work efficiency is poor and automation such as robotization is difficult.

On the other hand, a round rod-shaped ceramic member is inserted into one end of a hollow cylindrical metal member, and the part of the metal member surrounding the ceramic member is repeatedly cooled from the outside along the axial direction and then heated. Japanese Patent Application No. 167443 proposed a method of bonding a ceramic member and a metal member by sequentially moving the metal member through a high temperature range, thereby causing plastic deformation due to contraction in the metal member. FIG. 5 shows an example thereof.

In FIG. 5, reference numeral 1 denotes a hollow cylindrical metal member made of, for example, stainless steel, carbon steel, low alloy steel, or the like. Also, 2
is a round bar-shaped ceramic member, for example silicon nitride Si
, N, alumina AQ, O, silicon carbide SiC, etc. Then, this ceramic member 2 is inserted into one end of the metal member 1.

Then, the portion 1a of the metal member 1 surrounding the ceramic member 2 is repeatedly cooled along the axial direction by the cooling water 4 jetted from the cooling water nozzle 3 from the outside, and then heated by the high-frequency heating coil 5. Then, the low temperature region 6 and the high temperature region 7 are sequentially moved, and the movement of the axial temperature distribution consisting of the low temperature region 6 and the high temperature region 7 is carried out over the entire axial direction of the ceramic surrounding portion 1a of the metal member 1.
Do it twice or more.

As a result, the ceramic surrounding portion 1 of the metal member 1
Unlike the other parts 1b, shrinkage plastic deformation occurs in part a due to the thermal ratchet effect, and as a result, as shown in FIG. The portion 1a tightens the ceramic member 2, and the ceramic member 2 and the metal member 1 are combined.

As mentioned above, according to this method, the amount of shrinkage plastic deformation of the hollow cylindrical metal part can be adjusted by the number of passes of the axial temperature distribution, so there is no need to worry about the initial dimensions of the metal part. There's no need.

In addition, since the time of exposure to high temperatures is not as long as in the case of conventional bulk fitting, the ceramic member can be inserted into one end of the metal member at room temperature without causing scale to form on the inner surface of the metal part +1. , automation such as robotization is also easy.

Problems to be Solved by the Invention The method described in the above-mentioned Japanese Patent Application No. 1-67443 is a method that can be used practically, but when a slight axial force is applied to the rotating shaft when it rotates. , there is a possibility that the ceramic shaft may come off from the hollow cylindrical metal member.

The present invention was made in order to eliminate such problems, and an object of the present invention is to provide a bonding method that further increases the reliability of bonding a ceramic member and a metal member.

Means for Solving the Problems According to the present invention, a round bar-shaped ceramic member having an annular shape is compressed at one end of a hollow cylindrical metal member, and a portion of the metal member surrounding the ceramic member is axially The ceramic member and the metal member are bonded together by repeatedly cooling and then heating from the outside to move the metal member sequentially through a low temperature region and a high temperature region. A bonding method is provided which is characterized in that bonding is strengthened by the effect of.

According to the above-mentioned means, when the hollow cylindrical metal member undergoes shrinkage plastic deformation, a part of the metal member is plastically deformed toward the inside of the annular groove provided in the ceramic member. This strengthens the bond between the ceramic shaft and the metal member.

Embodiments Hereinafter, embodiments of the present invention will be described in detail with reference to FIGS. 1 and 2. In FIGS. 1 and 2, the same parts as those shown in FIGS. 3 to 6 are denoted by the same reference numerals, and detailed explanation thereof will be omitted.

According to FIGS. 1 and 2, a shallow annular groove 8 is provided in a portion where the ceramic member 2 overlaps the metal member 1. Other conditions are exactly the same as in the conventional example shown in FIG.

That is, the metal member 1 has a hollow cylindrical shape and is made of, for example, stainless steel, carbon steel, low alloy steel, or the like. In addition, 2 is a round bar-shaped ceramic member, for example, silicon nitride 5IJ
4. Consists of alumina Ao*os, silicon carbide SiC, etc. Then, this ceramic member 2 is pushed into one end of the metal member 1.

Then, the portion 1a of the metal member 1 surrounding the ceramic member 2 is repeatedly cooled along the axial direction by the cooling water 4 jetted from the cooling water nozzle 3 from the outside, and then heated by the high-frequency heating coil 5. Then, the low temperature region 6 and the high temperature region 7 are sequentially moved, and the movement of the axial temperature distribution consisting of the low temperature region 6 and the high temperature region 7 is carried out over the entire axial direction of the ceramic surrounding portion 1a of the metal member 1.
Do it twice or more.

As a result, the ceramic surrounding portion 1 of the metal member 1
Unlike the other parts 1b, shrinkage plastic deformation occurs in part 1a of the metal member 1 due to the thermal ratchet effect, and as a result, as shown in FIG. tightens the ceramic member 2, and also tightens the ceramic member 2 in the portion 1a of the metal member l.
The outer part IC of the annular groove 8 is plastically deformed due to contraction,
It has a shape that fits into the annular groove 8. Therefore, metal member 1
In addition to the tightening of the ceramic member 2 by the portion 1a, the insertion of the portion 1C of the metal member 1 into the annular groove 8 of the ceramic member 2 causes the ceramic member 2 and the metal member 1 to be more firmly connected, making it difficult for them to come off. Become.

Next, an experimental example will be described.

The metal member 1 has a pipe diameter of φ1400 mm and a plate thickness of 1 mm.
A round bar-shaped ceramic member 2 made of silicon nitride 5jsNa was inserted into one end of the hollow cylindrical member made of stainless steel (SOS 304). A shallow annular groove 8 with a depth of about 5 mm was provided in the round bar-shaped ceramic member 2.

Then, by cooling with the cooling water 4 spouted from the cooling water nozzle 3, the low temperature region 6 was made to reach a high temperature of about 50°C, and the high frequency heating coil 5 made the high temperature region to a high temperature of about 650°C. The temperature gradient between area 6 and
An axial temperature distribution of 5° C./w resulted.

Then, the moving distance of this axial temperature distribution is 601111
11 (approximately 7.2 times the claw, r: average radius, t: plate thickness), the thermal stress generated by the axial temperature distribution consisting of the high temperature region 7 and the low temperature region 6 is approximately 100 kg / mm.
Since the yield stress of SOS 304, which is the material of the metal member 1, is sufficiently large (approximately 14 kg/mm" at 650°C), when this temperature distribution shifts, the thermal ratchet effect causes the metal member 1 to Shrinkage plastic deformation occurred.

The amount of shrinkage plastic deformation in the radial direction of the metal member 1 that occurred during this one movement of the temperature distribution was about 0.04 mm.

Then, by repeating the temperature distribution movement 10 times, approximately 0.5
mII, shrinkage plastic deformation in the radial direction of about 0.9 mm after 50 repetitions and about 1 mm after 100 repetitions was observed, and the metal member 1 tightened the ceramic member 2, and the annular groove 8 of the ceramic member 2 It also got inside.

In addition, regarding the heat ratchet effect, it is important to note that there is a difference between heat and heat! It is known that plastic deformation of contraction or expansion of the hollow cylindrical member occurs depending on the direction of movement of j. When the same <60111Il movement was made so as to be in the low temperature region 6, a radial expansion plastic deformation of about 0.08-m occurred in one movement.

Effects of the Invention As described above, according to the present invention, the amount of shrinkage plastic deformation of a hollow cylindrical metal member can be adjusted by the number of passes of the axial temperature distribution, and it is no longer necessary to be so concerned about the initial dimensions of the metal member. In addition to the effect of Japanese Patent Application No. 1-67443 that the ceramic shaft and the metal hollow cylinder are not easily separated, a more reliable connection can be obtained.

In addition, since the time of exposure to high temperatures is not as long as in the case of conventional shrink fitting, the ceramic member can be inserted into one end of the metal member at room temperature without causing scale to form on the inner surface of the metal member. Automation such as robotization is also easy.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an example of the method of joining a ceramic member and a metal member according to the present invention, FIG. 2 is a diagram showing the joined state, and FIG. 3 is a diagram showing a method for joining a ceramic member and a metal member by shrink fitting. A diagram showing a conventional example of coupling, FIG. 4 shows a coupled state of the example in FIG. 3, FIG. 5 shows another conventional example, and FIG. 6 shows a coupled state of the example in FIG. It is a diagram. 1. Metal member, 2. Ceramic member, 8. Annular groove.

Claims (1)

[Claims] A round rod-shaped ceramic member with an annular groove is inserted into one end of a hollow cylindrical metal member, and the part of the metal member surrounding the ceramic member is repeatedly cooled from the outside along the axial direction and then heated to a low temperature. The ceramic member and the metal member are bonded by sequentially moving the ceramic member and the high temperature range, thereby causing plastic deformation due to contraction in the metal member,
A bonding method characterized by strengthening the bond with the effect of annular grooves.