JPS6224028A - Fastening method for ceramic and metal - Google Patents

Abstract

PURPOSE:To enhance the reliability for heat expansion and contraction by interposing an elastic body made of a plastic between a ceramic surface provided with whirl-stop and a metallic fastening surface. CONSTITUTION:First, a metallic plate 8 for fastening having a key 7 is inserted into a pump shaft 6. Next, after an elastic body 9 has been inserted, an impeller made of a ceramic, on the fastening surface 5 of which grooves 11 are provided, is inserted so that the fastening surface is brought into contact with the elastic body 9. And then, the impeller 1 made of a ceramic is tightened with a shaft nut 4 via a plastic-made ring 10 so as to be tightened to the shaft 6.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method of fastening ceramics and metal.

[Conventional technology]

Although various methods have been considered for fastening ceramics and metal, the reality is that there is no fastening method that is low cost, reliable, and durable. Particularly when using ceramics as the rotating body of a pump, such as the blades, the connection between the driving shaft and the ceramic impeller is a serious problem, and even though ceramics have excellent corrosion and abrasion resistance, However, the reason why its use is limited is because there was no way to connect ceramics and metal.

Conventional methods for joining (fastening) ceramics and metals include joining ceramics and metals using adhesives, metallizing the ceramic surface and joining it to metal using brazing filler metal, or machines using keyways. There are various joining methods.

The adhesive fastening method has problems with the reliability of the adhesive, especially its deterioration over time during immersion in water, etc.), and
There was also no durability due to n-off repetition.

Furthermore, when the surface of ceramics is metallized and bonded to metal, there are problems with reliability due to differences in thermal expansion and corrosion resistance of the bonding filler metal, so it cannot be used in general equipment such as actual pumps.

In addition, there is a mechanical fastening method by providing a keyway, etc., but in this case, since the metal and ceramic are in direct contact, stress concentration occurs on the ceramic side, which may lead to damage during repeated operation. [Problems to be Solved] Conventional methods for joining ceramics and metals lack reliability and durability against thermal expansion and contraction, are expensive, and have poor corrosion resistance against acid solutions, etc., and do not require direct contact. This has disadvantages such as causing damage to the ceramics.

The present invention seeks to solve these problems.

[Means for solving problems]

The present invention provides a method for fastening ceramics and metal, in which at least the fastening surface on the ceramic side is subjected to a round fastening process in various patterns, and then the round fastening surface of the ceramic and the fastening surface of gold 3 are connected to each other. This is a method of joining ceramics and metal by interposing an elastic body made of plastic between the ceramics and the metal, which prevents thermal expansion and contraction. This book can provide a fastening method that can sufficiently withstand stress, reduce stress concentration on the ceramic side, and prevent damage to the ceramic side.

First, a conventional example will be explained based on FIG.

FIG. 6 shows a cross-sectional view of the part where the metal impeller is attached to the shaft, where 1' is the metal impeller, 3' is the blade, 4 is the shaft nut, and 5 is the fastening surface of the metal impeller 11. , 6 indicates the axis, and 7 indicates the key.

In this conventional example, the metal impeller 1' is fixed to the shaft by fitting the key part of the metal impeller 1' into the keyway of the shaft 6 and fastening it with a rear shaft nut 4 inserted into the shaft. has been done.

Next, the present invention will be explained in detail based on FIGS. 1 to 5.

Fig. 1 shows a cross-sectional view of the part where the ceramic impeller is inserted and fastened to the shaft, Fig. 2 is a front view of the ceramic impeller, and Fig. 3 is taken along line A-A of the impeller shown in Fig. 2. 1 is a ceramic impeller, 2 is a shaft penetrating part, 3 is a blade, 4 is a shaft nut, 5 is a fastening surface of the ceramic impeller, 6 is a shaft, 7 is a key, and 8 is a fixed part. metal plate for
? 10 indicates an elastic body, and 10 indicates a plastic ring.

Moreover, FIGS. 4 and 5 are drawings for showing an example of the pattern of the rotation stopper provided on the fastening surface of the ceramic impeller 1, and in FIG. 4, four grooves are arranged in a cross shape. Fig. 5 shows a state in which three grooves are provided.

After first inserting the fixing metal plate with the key 7 into the pump shaft 6 and then inserting the elastic body 9, a ceramic impeller with grooves 11 formed in the fastening surface 5 in the pattern shown in FIG. The ceramic impeller 1 was fastened to the shaft 6 by inserting it so that the fastening surface was in contact with the elastic body, and then tightening the shaft nut 4 through the plastic ring 10.

The groove provided on the fastening surface 5 of the ceramic impeller has a width of 5 mm.
The depth was 1.5 cups. It's a trench, the impeller boss has an outer diameter of 42
vm, inner diameter 22 cod.

In this example, sufficient durability was demonstrated in the A7KW motor drive transmission.

When the groove-shaped pattern of this example was applied, no damage occurred even when the motor transmission shaft of 5.57 mm was turned on and off 100,000 times.

When machining grooves on ceramics, it is preferable to change the pattern (number of grooves) depending on the horsepower of the motor.

When the outer diameter of the impeller is 42 fins and the inner diameter is 22 fins, Z The relationship between motor horsepower and groove machining is shown in Table 1.

Motor horsepower Groove machining 2-2 KW: > 5 m The metal plate is a ring-shaped part that is fixed to the υ shaft by a key, and a groove similar to that provided on the fastening surface 5 of the ceramic impeller is also provided on the surface facing the ceramic impeller. It is preferable that

Note that in the case of a newly designed pump, it is possible to provide a single welding recess on the end face of the shaft, so a fixing metal plate is not necessary.

However, when large torque is transmitted between metal and ceramic, it is necessary to increase the area of the fastening surface.
It is desirable to use a fixing metal plate (that is, a large fastening surface) that has a larger diameter than the shaft diameter.

Furthermore, since the shaft nut is made of metal, it is difficult for it to directly contact and press the ceramic, so it is necessary to press it through the plastic ring 10. in this case,
Since pressing only applies pressure to the shaft nut side of the ceramic impeller, there is no need to take precautions such as providing rotational fastening.

〔Effect of the invention〕

According to the method of the present invention, it is possible to join ceramics and metal very simply and inexpensively, and it is also possible to provide a fastening method that is durable and reliable even when there are temperature changes.

Furthermore, even when changing only the impeller in an existing pump to a ceramic impeller, it is possible to replace the impeller with the same shape at low cost.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view of a ceramic impeller attached to the shaft of a tank to explain the method of the present invention, Figure 2 is a front view of the ceramic impeller, and Figure 5 is taken from A-A in Figure 2. 4 and 5 are diagrams showing examples of groove patterns provided on the fastening surface, and FIG. 6 is a diagram illustrating a conventional example.

Claims (1)

[Scope of Claims] 1. A method for fastening ceramics and metal, in which at least the fastening surface on the ceramic side is subjected to a fastening process in various patterns, and then the fastening surface of the ceramic and the metal are fastened together. A method of joining ceramics and metal by interposing a plastic elastic body between the surfaces. 2. The method according to claim 1, wherein the ceramic-side fastening surface is covered with a resin mask having cutouts in a desired pattern, and then a rounding process is performed by shot blasting using hard fine particles. 3. The method according to claim 1, wherein the pattern applied to the fastening surface on the ceramic side to be fastened is changed depending on the strength of the power to be transmitted. 4. The method according to claim 1, wherein the interposed elastic body is tightened by rotational driving to generate compressive stress on the ceramic side.