JPH0624853A - Production of ceramic made closed loop structure - Google Patents

Abstract

PURPOSE:To produce a ceramic made closed loop structure with high precision without decreasing the joining strength of a joining part. CONSTITUTION:Each of ceramic elements 1a-1d is held in a closed loop state by using a clamping devices 3-6 so as to allow the deformation caused by the expansion and the shrinkage of each of ceramic elements 1a-1d. Each of ceramic elements is joined by heating by the use of heating devices 7, 8 and 9 so that the elongation factor of each of the ceramic elements 1a-1d is substantially equal to each other when the temp. of each of butt joint parts of ceramic elements 1a-1d reaches an adequate joining temp.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a ceramic closed loop structure by joining two or more ceramic elements so as to form a closed loop.

[0002]

2. Description of the Related Art Most of the conventionally proposed ceramic joining techniques join two ceramics to be joined. Therefore, for example, almost no development has been made on manufacturing a ceramics closed loop structure by joining four ceramics elements 101a to 101d as shown in FIG. 8A to form a closed loop.

[0003]

The inventor tried to manufacture a closed loop structure as shown in FIG. 8 (A) by using various existing techniques, but no satisfactory result was obtained. For example, the example shown in FIG.
Two ceramic elements 10 are provided, one at each end of a.
1b and 101d are joined together by using a known joining method such as an electrical joining method to form two ceramic elements 101b and 101d.
This is an example in which the ceramic element 101c is attempted to be bonded to the end of the. Reference numeral 102 in the drawing denotes a joining completed portion which has been joined. In order to bond the ceramics element 101c to the ceramics element 101b, a bonding agent 103 is arranged between them to form a butt portion, and the butt portion is heated and joined by a known joining method such as an electric joining method. After melting the agent 103,
Bonding was performed by applying pressure so as to compress the melted bonding agent. However, when looking at the state after joining and cooling in this way, the gap g at the abutting portion between the ceramic elements 101c and 101d becomes too narrow, and both the ceramic elements 101a to 101d fall into this gap g. It was not possible to insert a bonding agent or a heating insert material for bonding the.

Therefore, as shown in FIG. 8C, the ceramic element 101c is replaced by the ceramic elements 101b and 10b.
I tried to join 1d at the same time. However, according to this method, the ceramic element 101c is expanded by the heat applied to the ceramic element 101c during the joining, and the joining is performed in a state where the end portions in the longitudinal direction extend beyond the end portions of the ceramic elements 101b and 101d or are displaced. To be done,
The shrinkage of the ceramics element 101c due to cooling after joining causes bending stress in the joining completed portion 104, and the joining completed portion 10
4 and the ceramic elements 101b to 101d were found to be cracked. Even if cracks do not occur, if this method is used, the joining is performed in the state where the protruding portion or the displaced portion is formed, so that the joining accuracy becomes extremely poor.

Therefore, four ceramic elements 101a ...
We considered joining 101d at the same time. In order to enable simultaneous bonding, it is necessary to clamp each ceramic element at the same time. Therefore, as shown in FIG. 8D, the clampers 105a to 105d used in the welding technique of steel are used.
Each ceramic element was clamped and bonded using. However, since the clamper used in the welding technology for steel is a fixed type, it is not possible to deal with the expansion of each ceramic element at the time of joining and the contraction of each ceramic element after joining, and when the bonding agent melts It was not possible to move each ceramic element so as to compress, and it was not possible to obtain high accuracy and sufficient strength.

An object of the present invention is to provide a method of manufacturing a ceramic closed loop structure with high accuracy without lowering the bonding strength of the bonded portion.

[0007]

According to the first aspect of the present invention, two or more members are formed so as to allow deformation caused by expansion of each ceramic element due to temperature rise and contraction of each ceramic element due to temperature drop and to form a closed loop. Holds the ceramic element. Then, when the temperature of each abutting part formed between the adjacent ceramic elements reaches an appropriate joining temperature, the two or more ceramic elements are made to have substantially the same elongation rate due to the temperature rise. To heat.

Each ceramic element is held by a movable clamp device such as a clamp device having a clamper attached to a table movable in the XY directions, a clamp device having a clamper attached to a table movable in the radial direction, or a fixed type. It can be easily realized by appropriately combining a clamp device, a table drive device, and the like.

Here, the proper joining temperature is determined on the basis of the melting temperature of the ceramic element used when the joining agent is not used, and is determined on the basis of the melting temperature of the joining agent when the joining agent is used. The elongation rate due to the temperature rise of each ceramic element should be substantially equal when the butted part reaches the proper joining temperature, but if a large temperature gradient is created in each ceramic element, the thermal stress causes the fracture stress When the butt joint is heated to the proper bonding temperature, the thermal stress generated inside each ceramic element is gradually heated so that it becomes smaller than the fracture stress. Preferably. As a heating source for heating the ceramic element,
Heat of a burner, Joule heat by an electric joining method, induction heating or the like can be used.

According to the second aspect of the present invention, the abutting portion is formed between the joining ends of two or more ceramic elements by interposing a joining agent that melts when heated to an appropriate joining temperature.

According to the third aspect of the invention, a heating insert material is provided between the joining ends of two or more ceramic elements, and a joining agent that is melted when heated to an appropriate heating temperature is provided on both surfaces of the conductive ceramic. To form a butt portion. Then, the main heating is performed by the electric bonding method.

According to the invention of claim 4, together with the main heating device for heating the butted portion, the amount of radiation heat can be reduced as the distance from the butted portion along the ceramic element is increased without changing the distance from the ceramic element. Use an auxiliary heating device.

The fifth aspect of the present invention is directed to a method of manufacturing a ceramic closed loop structure in which two or more ceramic elements form an even polygonal closed loop in which all opposing pairs of sides are parallel. In the present invention, two or more ceramic elements are held so as to allow the deformation caused by the expansion of each ceramic element due to the temperature rise and the contraction of each ceramic element due to the temperature drop and to form a closed loop. Then, when the temperature of each butt portion formed between the adjacent ceramic elements reaches an appropriate joining temperature, at least one pair of opposing sides of the closed loop have substantially equal elongation rates due to temperature rise so that they are equal to or more than two. The ceramic elements are heated and the two or more ceramic elements are joined together so as not to cause displacement at each butt portion.

[0014]

When each ceramic element is clamped using only the fixed type clamp device used in the welding technology of steel, expansion of each ceramic element due to temperature rise and contraction of each ceramic element due to temperature decrease cannot be tolerated. A protrusion phenomenon or a displacement phenomenon occurs in which joining is performed in a state where the ends of the ceramics element are displaced from the closed loop, or a crack is generated in the ceramics element made of ceramics because the stress generated inside is greater than or equal to the fracture stress. According to the invention of claim 1, since two or more ceramic elements are held in a closed loop state by allowing expansion of each ceramic element due to temperature rise and contraction of each ceramic element due to temperature decrease, an internal pressure that exceeds the fracture stress Generation of stress can be suppressed. Further, the work of compressing the bonding agent when the bonding agent is melted can be easily performed. The shift phenomenon cannot be eliminated only by changing the holding mode of each ceramic element. The cause of the displacement phenomenon is the difference in the amount of elongation of each ceramic element when the ceramic element is heated for bonding. Therefore, as in the present invention, when the temperatures of the abutting portions formed between the ceramic elements reach an appropriate joining temperature, the elongation rates of the two or more ceramic elements are substantially equal to each other due to the temperature rise. When the ceramic element of No. 1 is heated, it is possible to suppress the occurrence of the shift phenomenon at the time of joining. Therefore, according to the invention of claim 1, the closed loop structure can be manufactured with high accuracy.

When the bonding agent is used as in the second aspect of the invention, the closed loop structure can be manufactured with high accuracy. Further, when the main heating is performed by the electric bonding method as in the third aspect of the invention, if the insert material for heating is used, the closed loop structure can be manufactured using the ceramic element having no conductivity even at a high temperature.

Since a movable clamp device is used to hold each ceramic element, the number of objects to be controlled inevitably increases. Furthermore, if a moving heating source is used for the moving ceramic element, the number of objects to be controlled increases, and the control at the time of joining becomes troublesome. Therefore, as in the invention of claim 4, together with the main heating device for heating the butt portion, the amount of radiant heat can be reduced as the distance from the butt portion along the ceramic element is increased without changing the distance from the ceramic element. When the heating means is used, the number of objects to be controlled is reduced, which facilitates the control at the time of joining.

When an even polygonal closed loop structure in which all of a pair of opposing sides are parallel to each other is manufactured as in the fifth aspect of the present invention, the closed loop is generated when the temperature at each butting portion reaches an appropriate joining temperature. Position adjustment of each ceramic element by heating two or more ceramic elements so that the elongation rates of at least one pair of opposing sides of the above are substantially equal to each other due to temperature rise, and without causing misalignment at each butt portion. By doing so, even if the elongation rate of the pair of sides due to the temperature rise differs from the elongation rate of the other pair of sides due to the temperature rise, the joining can be performed without causing the shift phenomenon.

[0018]

Embodiments of the present invention will now be described in detail with reference to the drawings. 1 (A) to 1 (C) are views for explaining an example of manufacturing a regular square ceramic closed loop structure. FIG. 1A shows four ceramic elements 1a-
The closed loop state of the unjoined closed loop structure formed by arranging the bonding agent 2 at the abutting portion of 1d includes four clamp devices 3 to
6 schematically shows the holding state. If the ceramic elements 1a to 1d are made of the same ceramic material, the joining is easiest, but it goes without saying that the respective ceramic elements may be made of different ceramic materials. In this embodiment, the ceramic elements 1a to 1d are made of the same ceramic material, the ceramic elements 1a and 1c have the same length in the longitudinal direction, and the ceramic elements 1b and 1d have the same length in the longitudinal direction. And

FIG. 1B shows the ceramic elements 1a-1.
D is shown by an imaginary line to schematically show the configuration of the four clamp devices 3 to 6. The clamp device 3 is a fixed clamp device, and is composed of two positioning rollers 3b and 3c which are rotatably fixed to a roller bracket 3a with a predetermined interval. These rollers 3b and 3c
Is a large-diameter cylindrical portion 3b1 or 3c1 whose end face in the axial direction contacts one side surface of the ceramic element 1a and a small-diameter cylindrical portion 3 which contacts another side surface of the ceramic element 1a on the outer peripheral surface.
b2 and 3c2, and is made of an elastic material to allow expansion and contraction of the ceramic element 1a in the width direction to some extent. The clamping devices 4 and 6 are
Both are movable clamp devices, and these clamp devices are configured by rotatably fixing three positioning rollers 4b to 4d and 6b to 6d on XY tables 4a and 6a which can move in the XY directions. There is. Two rollers 4b,
4c and 6a, 6c are arranged along the longitudinal direction of the ceramic element 1b, and these two rollers 4b, 4a
The lines connecting c and 6a, 6c are the clamp device 3
Are orthogonal to the line connecting the two rollers 3a and 3b. Further, one roller 4d and 6d is spaced from the two rollers 4b, 4c and 6a, 6c in a direction orthogonal to the longitudinal direction, and the two rollers 4b and 4d are spaced apart from each other.
c and 6a, 6c and ceramic elements 1b and 1
Hold d. In this example, the rollers 4d and 6d connect the ceramic elements 1b and 1d to the two rollers 4b, 4c and 6 by urging means such as springs or cylinders (not shown).
The ceramic elements 1b and 1 are urged toward the a and 6c sides.
d is held. The rollers 4b to 4d and 6b to
The configuration of 6d is similar to that of the rollers 3a and 3b described above. The XY tables 4a and 6a are adapted to move in the XY direction by a light force, and the force generated when the ceramic element expands or contracts causes the XY table
It moves in the Y direction and moves in the Y direction when the clamp device 5 moves toward the clamp device 3 when compressing the molten bonding agent 2. The clamp device 5 is configured such that two positioning rollers 5d and 5e are rotatably fixed to a movable roller bracket 5c connected to a pressurizing cylinder 5a via a spherical bearing 5b. The movable roller bracket 5c is connected to the pressurizing cylinder 5a via the spherical bearing 5b because the movable roller bracket 5c is free to move and the ceramic element 1c accompanying the thermal expansion and contraction.
This is so as not to restrain the displacement of. The pressurizing cylinder 5a normally urges the movable roller bracket 5c to the extent that the displacement of the movable roller bracket 5c is allowed. However, when the bonding agent 2 is melted and then the bonding agent is compressed, a certain strong force is applied. The movable roller bracket 5c is urged toward the ceramic element 1c.

FIG. 1C schematically shows the relationship between the heating device and the energizing electrodes for the ceramic elements 1a, 1b, 1c without showing the clamp device. One heating energization unit device 7 and one heating energization unit device 8 are arranged on both sides in the thickness direction of the abutting portions formed between the adjacent ceramic elements with a bonding agent interposed therebetween. . This one heating energizing unit device 7
And one heating energization unit device 8 are combined to form one main heating device provided for one butt portion. It should be noted that the main heating device formed by combining the one heating energization unit device 7 and the one heating energization unit device 8 is arranged at each of the other butting portions not shown in FIG. 1C. . As will be described later in detail, 9 is an auxiliary heating device used in combination with the main heating device. Heating and energizing unit devices 7 and 8 constituting one main heating device
Are energized electrodes 7a and 8a, gas burners 7b and 8b for blowing out a gas flame from the periphery of the energized electrodes, and an energization device for energizing the energized electrodes 7a and 8a, respectively. And retreat devices 7c and 8c for individually retreating to the retreat position, and drive sources 7d and 8d for giving a driving force to the retreat device. It should be noted that a current is supplied from a control power supply (not shown) to the energizing devices built in the retractors 7c and 8c. The current-carrying electrodes 7a and 8a are flat plate-shaped electrodes having a width dimension substantially equal to the width dimension of the butted portion. The gas burners 7b and 8b are ring-shaped gas burners having gas flame openings so as to concentrically surround the bases of the current-carrying electrodes 7a and 8a.
In order to reduce the thermal stress generated around the abutting part before heating the temperature of the abutting part to a proper joining temperature by energizing a and 8a, and the conductivity of the ceramic and the bonding agent which show conductivity at high temperature. It is used to increase The retractors 7c and 8c can individually adjust the distance between the tips of the current-carrying electrodes 7a and 8a and the abutting portion of the ceramic element, and the distance between the gas flame openings of the gas burners 7b and 8b and the abutting portion of the ceramic element. Is configured. An air cylinder, a solenoid, a motor, etc. are used for the drive sources 7d and 8d.

Two auxiliary heating devices 9 are provided for each of the ceramic elements 1a to 1d, and they are used independently before using the main heating device provided for each butt portion. After heating each ceramic element, it is used together with each main heating device so that when the temperature at the butt reaches the proper joining temperature, the elongation rate due to the temperature rise of each ceramic element becomes substantially equal. Used to heat ceramic elements. It should be noted that the auxiliary heating devices 9 and 9 are configured so that the thermal stress generated inside each ceramic element is smaller than the fracture stress in the cooling process after the temperature of the butt portion reaches the proper bonding temperature and the bonding is performed. It has the function of heating the element.
As the auxiliary heating devices 9 and 9, heating means such as a gas burner, high frequency induction heating, an infrared lamp, and a small electric furnace can be used. These heating means can also be used in the main heating device.

Here, specifically, the meaning of heating each ceramics element so that the elongation percentages due to the temperature rise of all the ceramics elements become substantially equal when the temperature of the butt portion reaches the proper bonding temperature. explain. Figure 2 (A)
1A shows in stages the state before joining the unjoined closed loop structure of FIG. 1A, the state during joining, and the state where cooling is performed after joining. Assuming that the lengths of the sides of the regular square closed loop before joining are L1 respectively, if the lengths of the sides when joining are all L1 + λ1, that is, if the elongation amounts λ1 of the sides are equal, The shift phenomenon does not occur. In other words, this means that all the ceramic elements 1a to 1d should be heated so that the elongation rate K becomes K = .lambda.1 / L1. As a result, the closed loop maintains a similar relationship at any stage of before joining → during joining → after joining cooling.

Next, a specific method for joining closed loops using the apparatus shown in FIGS. 1B and 1C will be described. Here, as the ceramic elements 1a and 1c, 1
2 × 12 × 1000 mm prismatic Si3 N4 ceramics are used, and the ceramic elements 1b and 1d are 1
2 × 12 × 976 mm prismatic Si3 N4 ceramics was used. And the bonding agent is CaF2 which shows conductivity at high temperature.
A system binder was used. First, the auxiliary heating devices 9 and 9 were operated to heat each ceramic element as a whole. Then, while maintaining the heating by the auxiliary heating device, the retracting devices 7c and 8c are driven by the driving force of the driving sources 7d and 8d, and the gas burners 7b and 8b are advanced to a predetermined position to generate a gas flame from the gas burners 7b and 8b. I put it out. Gas burner 7b
And 8b used propane gas as a fuel.
When a flame with a strong thermal power is suddenly applied to the ceramics, cracks are generated in the ceramics element. Therefore, the thermal power is weakened at the beginning to heat the ceramics and gradually raise the temperature of the abutting portion and its vicinity. The heat power may be adjusted by adjusting the amount of gas supplied, but the retractors 7c and 8c may be used to adjust the position of the gas burners so that the gas burners 7b and 8b are gradually brought closer to the abutting portion. The butt section was heated to 850 to 900 ° C. by using the heating by the auxiliary heating devices 9 and 9 and the heating by the gas burners 7b and 8b in combination. When the temperature of the abutting portion reaches 850 to 900 ° C. is detected by a temperature detector using a radiation thermometer or a thermocouple (not shown), a current is applied between the energizing electrodes 7a and 8a according to a predetermined conductivity control pattern. Then, the temperature of the butt portion is the temperature at which the bonding agent 2 melts (1000 to 1500 ° C.)
Heated until. Regarding the temperature adjustment of the auxiliary heating devices 9 and 9, experiments were conducted in advance to find an appropriate adjustment pattern in relation to the adjustment pattern of heating by the gas burners 7b and 8b, and the adjustment was performed according to this adjustment pattern. The adjustment pattern for preheating by the gas burners 7b and 8b and the auxiliary heating devices 9 and 9 is such that each ceramic element is heated so that the thermal stress generated inside each ceramic element becomes smaller than the fracture stress, and the closed loop It is set so that it will eventually become a similar figure.

After the melting of the bonding agent 2 is confirmed, the pressurizing cylinder 5a of the clamp device 5 is driven to move the movable roller bracket 5c toward the clamp device 3 by a predetermined distance, whereby the melted bonding agent 2 is removed. Compressed.
After the compression, when the temperature is drastically lowered, the ceramic element is cracked by the thermal stress. Therefore, the heating temperature by the auxiliary heating devices 9, 9 and the gas burners 7b and 8b is gradually lowered to perform cooling.

During energization and cooling, the clamp devices 4, 5, and 6 for holding each ceramic element move away from or approach the center of the closed loop according to the expansion of each ceramic element and the contraction accompanying cooling. However, the angle and flatness between the ceramic elements are not impaired.

In the ceramic closed loop structure manufactured as described above, neither a displacement phenomenon nor a crack was generated in the joint portion and the ceramic element. It was also found that the joint strength of the joint was 500 MPa or more.

In the apparatus shown in FIG. 1B, even when rectangular closed loop structures are joined, each ceramic is made to have substantially the same elongation rate due to temperature rise in all the ceramic elements. It suffices to heat the element.
FIG. 2 (B) illustrates the process in this case before joining → during joining → after joining cooling. In this example, two opposing sides having a length of L1 and two opposing sides having a length of L2 before joining.
When the sides are heated to the proper joining temperature at the butt portion, and the sides are L1 + λ1 and L2 + λ2 respectively, the elongation rate K of each side is K = (λ1 / L1) =
Each ceramic element is heated so as to become (λ2 / L2).

The above idea can be applied to any polygonal closed loop structure. When it is applied to a triangular closed loop, the process is as shown in FIG. 2 (C) before joining → during joining → after joining cooling. In this example, when there is a side having a length of L1, a side having a length of L2, and a side having a length of L3 before joining, the abutting portion of each ceramic element has an appropriate joining temperature. When each side becomes L1 + λ1 and L2 + λ2 and L3 + λ3 when heated up to, the elongation rate K of each side is K = (λ1 / L1)
Each ceramic element is heated so that = (λ2 / L2) = (λ3 / L3).

FIGS. 3A and 3B are views for explaining an embodiment for manufacturing a regular hexagonal ceramic closed loop structure. FIG. 3 (A) shows a case where the cement 1
2 schematically shows a state in which the closed loop state configured by arranging 2 is held by using six clamp devices 13 to 18. FIG. 3B shows the ceramic elements 11a to 11f.
Is indicated by an imaginary line to schematically show the configuration of the six clamp devices 13 to 18. Since all of these clamp devices have the same configuration, the structure will be described using the clamp device 17 as an example. The clamp device 17 includes three positioning rollers 17b to 17 on a table 17a that can move in the radial direction.
d is rotatably fixed, and a cylinder rod of an air thin lid 17f is fixed to the table 17a as a drive source. The two rollers 17b and 17c are arranged along the longitudinal direction of the ceramic element 11e, and the lines connecting the two rollers 17b and 17c are
It is orthogonal to the radiation passing through the center point CP.
Also, one roller 17d is two rollers 17b, 17c.
Are arranged radially inwardly from the two rollers 17b, 17 to hold the ceramic element 11e between them. In this example, the roller 17d is urged toward the ceramic element 11e by an urging means such as a spring or a cylinder (not shown) so that the ceramic element 11e is held. Note that the rollers 17b to 17d have a simple cylindrical shape, unlike the rollers 3a and 3b described above.
Needless to say, these rollers 17b to 17d may have the same structure as the rollers 3a and 3b described above.

When this device is used, each of the clamp devices 13 to 13 is operated until the temperature of the butt portion reaches the proper joining temperature.
The 18 air cylinders (17e) are set in a state where they can move freely to some extent. Then, when the temperature of the butt portion reaches the proper joining temperature and the molten joining agent is compressed, the air cylinders (17e) of all the clamp devices 13 to 18 are pressed.
Is driven to move the table (17a) radially inward. Then, in the cooling process, the air cylinder (17e) is again used.
Back to a state where it can move freely to some extent. Although the heating energizing unit device is not shown in FIG. 3, the heating energizing unit devices 7 and 8 shown in FIG. 1C can be used as they are for the abutting portions.
Further, although the auxiliary heating device is not shown in FIG. 3, the auxiliary heating device may be provided based on the same idea as that of the previous embodiment described with reference to FIGS. 1 and 2.

The method of the present invention is not limited to the case of manufacturing the closed loop structure of the polygonal closed loop as in each of the above-mentioned embodiments, but is applicable to the case of manufacturing the closed loop structure of the circular closed loop and the elliptical closed loop. Can also be applied.
FIG. 4 (A) shows a circular closed loop state in which the bonding agent 22 is arranged at the abutting portions of four ceramic arc-shaped ceramic elements 21a to 21d.
3 to 26 are used to schematically show the holding state. As these clamp devices 23 to 26, FIG.
The same structure as the clamp device 17 shown in (B) can be used. The auxiliary heating device and the main heating device are not shown. FIG. 4B shows a state before joining the closed loop of FIG. 4A, a state during joining, and a state in which cooling is performed after joining in a stepwise manner. If the arc length (outer or inner length) of each of the arc-shaped ceramic elements 21a to 21d before joining is L1, and the lengths of the respective sides when preheating and energizing are all L1 + λ1 The shift phenomenon does not occur. This means that the preheating may be performed so that the elongation rates K of the ceramic elements 21a to 21d at the time when the temperature of the abutting portion of each ceramic element reaches the proper joining temperature are all K = λ1 / L1. I mean. As a result, the closed loop can maintain a substantially similar relationship at any stage of before joining → during joining → after joining cooling.

FIG. 5 shows that an elliptic closed loop state, in which a bonding agent is arranged at the abutting portions of eight ceramic arc-shaped ceramic elements 31a to 31g, is held using eight clamp devices (not shown). In the case of performing the joining by joining, the state before joining the closed loop, the state during joining, and the state where cooling is performed after joining are shown in stages. A pair of ceramic elements 31a facing each other with the center of the closed loop in between.
And 31e and 31b and 31f have an arc length (outer or inner length) of L2, and the ceramic elements 31c and 31g and 31d and 31h have an arc length (outer or inner length), respectively. Suppose it was L1. In order to prevent the displacement phenomenon, the elongation rates of the ceramic elements 31a to 31h at the time when the temperature of the abutting portion of each ceramic element reaches the proper joining temperature are made equal. That is, the length of each element is heated to L1 +
When λ1 or L2 + λ2 is reached, heating is performed so that the elongation rate K of each ceramic element is K = λ1 / L1 = λ2 / L2. As a result, the closed loop can maintain a substantially similar relationship at any stage of before joining → during joining → after joining cooling.

In each of the above-mentioned embodiments, when a closed-loop structure having an arbitrary shape is manufactured using three or more ceramic elements, when the temperature at the abutting portion of each ceramic element reaches the proper joining temperature, all the The heating is performed so that the elongation percentages of the ceramic elements are substantially equal. However, when joining even-polygonal closed-loop structures in which all pairs of opposing sides are parallel to each other, at least one of the opposing sides is joined when the temperature at the abutting portion of each ceramic element reaches the proper joining temperature. The closed loop can be joined by heating so that the elongation percentages of the ceramic elements forming the pair of sides are substantially equal to each other and adjusting the positions of the respective ceramic elements appropriately. For example, when a regular quadrangular or rectangular closed loop is joined, heating is performed so that the elongation percentages of the ceramic elements forming one pair of opposite sides are substantially equal, and when a regular hexagonal closed loop is joined, The heating may be performed by setting the elongation rate of the ceramic element forming one pair of opposite sides to be different from that of the ceramic elements forming the other two pair of sides. Then, the misalignment generated at each butt portion can be eliminated by appropriately driving the clamp device to maintain the closed loop state.

As shown in FIGS. 6A and 6B, 2
It is also possible to manufacture a closed loop structure using individual ceramic elements. In the example of FIG. 6A, the I-shaped ceramic element 33 and the U-shaped ceramic element 34 are joined. Further, in the example of FIG. 6B, the U-shaped ceramic elements 35 and 36 are joined. In the preheating, the unbonded closed loop structure made by combining these ceramic elements is heated so as to maintain the similar shape, and in the main heating, the two butt portions are simultaneously heated.

Although any type of heating device can be used as the auxiliary heating device when carrying out the method of the present invention, the distance from the ceramic element can be changed in terms of installation space and simplification of control. Instead, it is preferable to use an auxiliary heating device that can reduce the amount of radiant heat as it goes away from the abutting portion along the ceramic element. 7 (A) and 7 (B) show a schematic configuration of an auxiliary heating device suitable for use when carrying out the method of the present invention. In FIG. 7A, 40 is an auxiliary heating device, 50 is a main heating device, and 60 is a ceramic element. The auxiliary heating device 40 includes a heat source such as a gas burner and a hot air generator in a case 41, and an opening 42 for releasing heat is formed in the upper lid of the case 41. The opening width of the opening 42 gradually becomes narrower as it goes away from the main heating device 50 along the longitudinal direction of the ceramic element 60. The smaller the opening width, the smaller the amount of heat radiated from that portion. Therefore, by providing such an opening 42, the ceramic element 60 does not have to change the distance between the auxiliary heating device 40 and the ceramic element 60 and does not require complicated control.
The amount of radiant heat can be gradually changed along. Figure 7
The auxiliary heating device 40 'shown in (B) has the same internal structure as the auxiliary heating device 40 described above, and a plurality of openings 42' ... Is formed at a predetermined interval on the upper lid of the case 41 '. It is different in that it is done. The diameter of each opening 42 '...
It becomes smaller as it goes away from the main heating device 50 along the longitudinal direction of the ceramic element 60. The smaller the diameter of the opening, the smaller the amount of heat radiated from the opening. Therefore, the auxiliary heating device 40 and the ceramic element 6 are also provided by providing such openings 42 '.
It is possible to gradually change the amount of radiant heat along the ceramic element 60 without changing the distance from 0 and without requiring complicated control.

When an electric bonding method is used for main heating and an insulating ceramic element is bonded, a conductive bonding agent is used, or a heating insert is prepared by providing a bonding agent on both surfaces of the conductive ceramics. Of course, a material may be used.

[0037]

According to the first aspect of the present invention, when the temperature of each butted portion formed between the ceramic elements reaches the proper joining temperature, the elongation rate of two or more ceramic elements due to the temperature rise is substantially increased. Since two or more ceramic elements are heated so as to be equal to, it is possible to suppress the occurrence of the shift phenomenon at the time of joining, and it is possible to manufacture the closed loop structure with high accuracy.

According to the second and third aspects of the present invention, the closed loop structure can be manufactured with high accuracy using the bonding agent and the heating insert material.

According to the fourth aspect of the present invention, since the auxiliary heating means that can reduce the amount of radiant heat as the distance from the abutting portion moves along the ceramic element without changing the distance from the ceramic element, the number of control objects is reduced. There is an advantage that it can be reduced and control at the time of joining becomes easy.

According to the invention of claim 5, when manufacturing an even polygonal closed loop structure in which all the pair of opposing sides are parallel to each other, the elongation percentages of all the ceramic elements do not have to be substantially equal. Also has the advantage that an even polygonal shape closed loop structure can be manufactured.

[Brief description of drawings]

FIG. 1A is a diagram schematically showing a relationship between a ceramics element and a clamp device in the case of manufacturing a square closed loop structure, and FIG. 1B is a schematic configuration diagram of the clamp device. C) is a diagram schematically showing the relationship between the heating device and the current-carrying electrodes for the ceramic element.

FIG. 2A is a diagram showing stepwise a state before joining the closed loop of FIG. 1A, a state during joining, and a state where cooling is performed after joining, and FIG. It is a figure which shows the state before joining a rectangular closed loop, the state during joining, and the state which cooled after joining stepwise, (C) shows the state before joining a triangular closed loop, and joining. It is a figure which shows the state inside and the state which cooled after joining stepwise.

FIG. 3A is a diagram schematically showing the relationship between a ceramic device and a clamp device when manufacturing a regular hexagonal closed loop structure, and FIG. 3B is a schematic configuration diagram of the clamp device.

FIG. 4A is a diagram schematically showing a relationship between a ceramics element and a clamp device when manufacturing a circular closed loop structure, and FIG. 4B is a state before the circular closed loop is joined and a state during joining. It is a figure which shows the state of and the state which cooled after joining stepwise.

FIG. 5 is a diagram showing stepwise a state before joining the elliptical closed loops, a state during joining, and a state in which cooling is performed after joining.

6A and 6B are views for explaining an example of manufacturing a closed loop structure using two ceramic elements.

7 (A) and 7 (B) are diagrams showing examples of an auxiliary heating device.

8 (A), (B), (C) and (D) are diagrams for explaining problems that occur when a ceramic closed loop structure is manufactured by using an existing technique.

[Explanation of symbols]

1a to 1d, 11a to 11f, 21a to 21d, 31a
~ 31h Ceramics element 2,12,22 Bonding agent 3-6,13-18,23-26 Clamping device 7,8 Heating energizing unit device 9 Auxiliary heating device

Claims (8)

[Claims] 1. A method for manufacturing a ceramic closed loop structure by joining two or more ceramic elements so as to form a closed loop, wherein expansion of each ceramic element due to temperature increase and contraction of each ceramic element due to temperature decrease. The two or more ceramic elements are held so as to allow the deformation caused by the cause and form a closed loop, and when the temperature of each abutting part formed between the adjacent ceramic elements reaches an appropriate joining temperature, A ceramic closed loop structure, characterized in that the two or more ceramic elements are heated to bond the two or more ceramic elements so that the elongation rates due to temperature rise of the ceramic elements are substantially equal. Production method. 2. The ceramics according to claim 1, wherein a joining agent that melts when heated to the proper joining temperature is interposed between the joining ends of the two or more ceramic elements to form the butting portion. Method for manufacturing closed loop structure. 3. A heating insert material, in which a bonding agent that melts when heated to the proper bonding temperature is provided on both surfaces of the conductive ceramics is arranged between the bonding ends of the two or more ceramic elements. The method for manufacturing a ceramic closed loop structure according to claim 1, wherein the butt portion is configured, and heating of the butt portion is performed by an electric joining method. 4. In the heating, together with a main heating device for heating the butted portion, the amount of radiant heat is decreased as the distance from the butted portion along the ceramic element is increased without changing the distance from the ceramic element. The method for manufacturing a ceramic closed loop structure according to claim 1, wherein an auxiliary heating device that can be used is used. 5. A method for producing a ceramic closed loop structure in which two or more ceramic elements form an even polygonal closed loop in which all opposing pairs of parallel sides are parallel to each other. The temperature of each butting portion formed between adjacent ceramic elements, which holds the two or more ceramic elements so as to form a closed loop while allowing deformation caused by expansion and contraction of each ceramic element due to temperature decrease. The two or more ceramic elements are heated so that the elongation rates of at least one of the pair of opposed sides of the closed loop due to the temperature rise become substantially equal when the temperature reaches an appropriate bonding temperature. Ceramics characterized in that the two or more ceramic elements are joined together without causing a displacement Method for manufacturing a loop structure. 6. The ceramics according to claim 5, wherein a joining agent that melts when heated to the proper joining temperature is interposed between the joining ends of the two or more ceramic elements to form the butting portion. Method for manufacturing closed loop structure. 7. A heating insert material, in which a bonding agent that melts when heated to the proper bonding temperature is provided on both surfaces of a conductive ceramic, is disposed between the bonding ends of the two or more ceramic elements. The method for manufacturing a ceramic closed loop structure according to claim 5, wherein the butt portion is configured, and the butt portion is heated by an electric joining method. 8. In the heating, together with a main heating device for heating the butted portion, the amount of radiant heat is reduced as the distance from the butted portion is increased along the ceramic element without changing the distance from the ceramic element. The method for manufacturing a ceramic closed loop structure according to claim 5, 6 or 7, which uses an auxiliary heating device that can be used.