JP2006010223A - Sheath for ceramic firing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sheath for ceramic firing capable of improving a yield rate by inhibiting the failure in firing and the variation of characteristic, and improving the working efficiency in packing a ceramic molding into a sheath. <P>SOLUTION: The sheath 10 comprises a rectangular frame part 11 and a loading part 13 for loading the ceramic molding 1, and devoid of a bottom. The frame part 11 has two first parts 11a, 11b opposite to each other when observed in the X-axis direction, and two second parts 11c, 11d opposite to each other when observed from the Y-axis direction. The frame part 11 has an opening 15 formed by the first parts 11a, 11b and the second parts 11c, 11d. The loading part 13 is detachable from the frame part 11, and hung on the parts opposite to each other of the frame part 11, that is, the first parts 11a, 11b and a third part 11e of the frame part 11 in a state of crossing the opening 15. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a sheath for ceramic firing.

As a sheath (a mortar) used when firing a ceramic molded body (for example, a ring-shaped ceramic molded body in which a through hole is formed), a groove for storing a plurality of ceramic molded bodies arranged side by side in the thickness direction is provided. The formed board-shaped sheath is known (for example, refer patent document 1).
JP-A-8-128789

  An object of the present invention is to provide a ceramic firing sheath that can suppress firing defects and characteristic variations, improve yield, and improve the sheathing efficiency of the ceramic molded body.

  As a result of intensive studies on a method for firing a ceramic molded body that can suppress firing defects and characteristic variations and improve the pod filling efficiency, the present inventors have newly found the following facts.

  It has been newly found that when a ceramic molded body is fired using the sheath described in Patent Document 1, firing defects and characteristic variations are caused. Usually, sheaths in which ceramic compacts are arranged are stacked in multiple stages and introduced into a firing furnace, and the ceramic compacts are fired in a desired firing atmosphere. When the plate-shaped sheaths are stacked, the gas constituting the firing atmosphere (hereinafter referred to as “atmosphere gas”) that flows into the sheath (in the space between the sheath located on the upper side and the sheath located on the lower side). It will be discharged from the sheath without moving between the sheaths. Therefore, when there is a sheath where it is difficult for the atmospheric gas to flow in, the sheath cannot adjust the surroundings of the ceramic molded body to a desired firing atmosphere, or the combustion component generated from the ceramic molded body can be smoothed from the sheath. The ceramic molded body is fired in a state where it cannot be discharged. As a result, the fired ceramic molded body, that is, the ceramic sintered body, has poor firing and characteristic variations between the sheaths.

  By the way, in recent years, there is a strong demand for downsizing and thinning of electronic components used in electronic devices, and in order to obtain a ceramic sintered body used for electronic components such as voltage-dependent nonlinear resistors (hereinafter referred to as varistors). It is also necessary to make the ceramic molded body small and thin. When the ceramic molded body is downsized, the sheathing operation of the ceramic molded body becomes complicated.

  Based on such research results, the sheath for ceramic firing according to the present invention includes a frame portion that forms an opening, and a placement portion on which the ceramic molded body is placed. It is detachable, and is spanned across mutually opposing portions of the frame so as to cross the opening.

  In the ceramic firing sheath according to the present invention, when a plurality of the sheaths are stacked, the atmosphere gas that has flowed into the stacked sheaths has no bottom with each sheath forming an opening. It circulates in the inner space defined by the sheath. As a result, it is possible to suppress firing defects and characteristic variations.

  Further, in the present invention, the mounting part is removable from the frame part, and is laid over the mutually opposing portions of the frame part so as to cross the opening. It becomes possible to arrange in the frame. As a result, even when the ceramic molded body is downsized, it is possible to improve the sheathing work efficiency.

  Moreover, it is preferable that the mounting part is formed with a recess having a concave cross section and extending in the longitudinal direction of the mounting part. In this case, the ceramic molded body can be arranged on the mounting portion in a state where the ceramic molded body is aligned in the thickness direction of the ceramic molded body and aligned along the concave portion.

  Moreover, it is preferable that the recessed part is provided with the vertical wall extended in the direction which cross | intersects the longitudinal direction of a mounting part. In this case, the ceramic molded body disposed in the recess by the vertical wall can be prevented from falling.

  Moreover, it is preferable that the recessed part which a mounting part engages in the part which mutually opposes in a frame part is formed. In this case, the placement portion can be positioned by the recess.

  Moreover, it is preferable that the convex part is formed in the upper surface of a frame part. When a plurality of sheaths are stacked, a wide gap is formed in the vertical direction (in the thickness direction of the frame portion) between the sheath located on the upper side of the two adjacent sheaths and the sheath located on the lower side by the convex portion. Is done. Therefore, when firing the ceramic compacts in the stacked sheaths, the atmospheric gas flows well into the stacked sheaths through the wide gap. As a result, it is possible to further suppress the occurrence of defective firing and variation in characteristics.

  According to the present invention, it is possible to provide a ceramic firing sheath that can suppress firing defects and variation in characteristics, improve yield, and improve the sheathing efficiency of the ceramic molded body.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, a preferred embodiment of a sheath for firing ceramics according to the present invention will be described in detail with reference to the accompanying drawings. In the description, the same reference numerals are used for the same elements or elements having the same function, and redundant description is omitted.

  In this embodiment, the present invention is applied to a sheath used in a method of manufacturing a porcelain (hereinafter referred to as a varistor porcelain) that uses the varistor. FIG. 1 is a flowchart for explaining the manufacturing process of the varistor ceramic according to the present embodiment. In addition, about a well-known manufacturing process, description is simplified.

  First, the ceramic molded body 1 is molded (molding step: S101). In the molding step S101, the raw material powder is processed in the order of mixing, calcination, pulverization, and molding to obtain the ceramic molded body 1 in which the through holes 3 are formed (see FIGS. 2A and 2B). Fig.2 (a) is a top view which shows a ceramic molded body, FIG.2 (b) is a side view which shows a ceramic molded body.

  As the raw material powder, a compound powder of each element constituting the varistor porcelain is usually used. As the raw material powder, an oxide or a compound that becomes an oxide by firing, such as a carbonate or a hydroxide, can be used. The raw material powder is weighed so that the final composition becomes a desired composition, and mixed (for example, wet mixing). Next, after dehydration, it is dried and pre-baked for about 2 to 4 hours at about 1080 to 1250 ° C., for example. Next, after pulverizing the temporarily fired product, an organic binder is added, and water, a pH adjuster, a moisturizing agent, and the like are further added and mixed. Next, the mixture is molded into a ring shape. The outer peripheral shape of the ceramic molded body 1 and the shape of the through-hole 3 are circular in plan view.

  Next, the plurality of ceramic molded bodies 1 are arranged on the sheath 10 (pod filling step: S103). In the sheath filling step S103, first, a sheath 10 is prepared (see FIGS. 3 to 7). 3 and 5 are perspective views showing the sheath. FIG. 4 is a plan view showing the sheath. 6 is a cross-sectional view taken along line VI-VI in FIG. 4, and FIG. 7 is a cross-sectional view taken along line VII-VII in FIG.

  The sheath 10 includes a rectangular frame portion 11 and a placement portion 13 on which the ceramic molded body 1 is placed, and is bottomless. The frame portion 11 includes two first portions 11a and 11b that face each other when viewed in the X-axis direction, and two second portions 11c and 11d that face each other when viewed in the Y-axis direction. The frame part 11 forms an opening 15 by the first parts 11a and 11b and the second parts 11c and 11d. The frame portion 11 further includes a third portion 11e connected to the two portions 11c and 11d facing each other in the frame portion 11. The third portion 11e extends between the two portions 11c and 11d so as to divide the opening 15 so as to face the first portions 11a and 11b. As a material of the frame part 11 and the mounting part 13, a material having heat resistance (fire resistance), for example, alumina, mullite, zirconia, or the like is used.

  The frame portion 11 includes a first upper surface 30 located at the first portions 11a and 11b of the frame portion 11, and a second upper surface 32 located at the second portions 11c and 11d of the frame portion 11. . The first upper surface 30 and the second upper surface 32 are not necessarily located at the same height.

  A plurality of recesses 40 are formed on the first upper surface 30 of each first portion 11a, 11b. Each recess 40 is a groove having a substantially arcuate vertical cross-sectional shape. The depth of the concave portion 40 (the thickness in the vertical direction of the frame portion 11 at the position where the concave portion 40 is formed) is a state in which the mounting portion 13 on which the ceramic molded body 1 is disposed is supported by the frame portion 11 as described later. Thus, the ceramic molded body 1 arranged on the mounting portion 13 is set so as not to protrude from the sheath 10 (frame portion 11), that is, the ceramic molded body 1 is set within the thickness range in the vertical direction of the sheath 10. Has been. The interval between the concave portions 40 is set so that the adjacent placement portions 13 do not contact each other when the placement portion 13 on which the ceramic molded body 1 is similarly disposed is supported by the frame portion 11.

  Convex portions 34 are respectively formed at the four corners of the frame portion 11. Each convex portion 34 has a substantially trapezoidal longitudinal cross-sectional shape, and is a portion formed so as to protrude from the first upper surface 30 and the second upper surface 32. The upper surface of the convex portion 34 comes into contact with the lower surface 36 of the sheath 10 positioned on the upper side when the sheaths 10 are stacked in multiple stages.

  A plurality of convex portions 42 are formed at predetermined intervals on the first upper surface 30 of the first portions 11a and 11b. Each convex portion 42 has a substantially trapezoidal longitudinal cross-sectional shape, and is a portion formed so as to protrude from the first upper surface 30. The tops of the convex portions 42 are located at the same height as the top surfaces of the convex portions 34 located at the four corners of the frame portion 11. Therefore, the convex part 42 contacts the lower surface 36 of the sheath 10 positioned on the upper side when the sheaths 10 are stacked in multiple stages.

  A convex portion 44 is formed on the second upper surface 32 of each of the second portions 11c and 11d. Each convex portion 44 has a substantially trapezoidal longitudinal cross-sectional shape, and is a portion formed so as to protrude from the second upper surface 32. The tops of the convex portions 44 are located at the same height as the top surfaces of the convex portions 34 located at the four corners of the frame portion 11. Therefore, like the convex part 42, the convex part 44 contacts the lower surface 36 of the sheath 10 positioned on the upper side when the sheaths 10 are stacked in multiple stages.

  On the upper surface of the convex portion 34 of the frame portion 11, when the sheath 10 is stacked, a raised portion 46 that engages with the sheath 10 located on the upper side and prevents lateral displacement is formed. Stepped portions 48 are formed at positions corresponding to the raised portions 46 at the four corners of the lower surface 36 of the sheath 10. The step-down portion 48 is formed so as to be drawn from the lower surface 36 to the upper surface side of the convex portion 34. When the sheath 10 is stacked, the raised portion 46 of the frame portion 11 of the sheath 10 located on the lower side is engaged with the stepped-down portion 48.

  A plurality of recesses 60 are formed at equal intervals on the upper surface of the third portion 11e. Each recess 60 is a groove having a substantially arc-shaped longitudinal section. The depth of the concave portion 60 (the thickness in the vertical direction of the third portion 11e at the position where the concave portion 60 is formed) is supported by the frame portion 11 on which the ceramic molded body 1 is disposed, as will be described later. In such a state, the ceramic molded body 1 disposed on the mounting portion 13 does not protrude from the sheath 10 (frame portion 11), that is, the ceramic molded body 1 falls within the thickness range of the sheath 10 in the vertical direction. Is set to The interval between the recesses 60 is the same as the interval between the recesses 40, so that when the mounting unit 13 on which the ceramic molded body 1 is arranged is supported by the frame unit 11, the adjacent mounting units 13 do not contact each other. Is set. The concave portion 40 formed on the first upper surface 30 and the concave portion 60 formed on the upper surface of the third portion 11e are such that the mounting portions 13 are substantially parallel to each other and orthogonal to the two portions 11a and 11b. They are formed so as to be associated with each other so that they are positioned at the positions to be operated.

  On the upper surface of the third portion 11e, a plurality of convex portions 62 are formed at a predetermined interval. Each convex portion 62 has a substantially trapezoidal vertical cross-sectional shape, and is a portion formed so as to protrude from the upper surface of the third portion 11e. The top of the convex portion 62 is located at the same height as the top surface of the convex portion 34, the top of the convex portion 42, and the top of the convex portion 44. The lower surface of the third portion 11 e is located at the same height as the lower surface 36 of the frame portion 11. Therefore, when the sheath 10 is stacked in multiple stages, the convex portion 62 comes into contact with the upper surface of the third portion 11e of the sheath 10 positioned on the upper side.

The mounting portion 13 is detachable from the frame portion 11 and is opposed to each other in the frame portion 11 so as to cross the opening 15, that is, the first portions 11 a and 11 b and the third portion 11 e of the frame portion 11. It is passed over to. The mounting portion 13 is formed with a concave portion 70 having a concave cross section and extending in the longitudinal direction of the mounting portion 13. In the present embodiment, the placing portion 13 has a shape in which a pipe is vertically divided in half (half-pipe shape). The recess 70 is a groove having a substantially arcuate vertical cross-sectional shape. The mounting portion 13 has one end of the mounting portion 13 engaged with the recess 40 formed on the first upper surface 30 of the first portions 11a and 11b, and the other end formed on the upper surface of the third portion 11e. By engaging with the recessed portion 60 formed, both ends thereof are supported by the sheath 10 (frame portion 11). The surface of the recess 70 is preferably coated with zirconium oxide (ZrO ₂ ) in order to prevent reaction of the ceramic molded body 1 due to contact.

  When the sheath 10 is prepared, first, the ceramic molded body 1 is placed in the concave portion 70 while being aligned in the longitudinal direction of the concave portion 70 of the placement portion 13. Thereby, the some ceramic molded object 1 will be distribute | arranged to the mounting part 13 in the state aligned in the thickness direction of the said ceramic molded object 1, and aligned along the recessed part 70 (refer FIG. 8). FIG. 8 is a perspective view showing the placement portion.

  Subsequently, the plurality of mounting portions 13 on which the ceramic molded body 1 is arranged are bridged over the portions 11a and 11b and the third portion 11e of the opposing frame portion 11 of the sheath 10, and both ends of the mounting portion 13 are placed. Are supported by the corresponding portions 11a, 11b, and 11e, respectively, and are arranged substantially in parallel (see FIGS. 9 and 10). Each placement portion 13 is positioned by the recesses 40 and 60. As a result, the plurality of ceramic molded bodies 1 are packed into the sheath 10 and arranged on the sheath 10. 9 is a perspective view showing a sheath, and FIG. 10 is a cross-sectional view taken along line XX in FIG. 9 and 10 depict a state in which the sheath 10 supports the mounting portion 13 on which the ceramic molded body 1 is disposed.

  As can be seen from FIGS. 4 and 9, the length of the mounting portion 13 is set to a length corresponding to the distance between the third portion 11e and the first portions 11a and 11b. A plurality (two in this embodiment) of the placement units 13 are arranged in the central axis direction of the placement unit 13.

Next, the ceramic molded body 1 is fired in the firing furnace 20 (firing step: S105). As shown in FIG. 11, the firing furnace 20 has an inlet portion 21 at one end and an outlet portion 23 at the other end, and has a tunnel shape. In the firing furnace 20, the firing atmosphere is a reducing atmosphere, and the gas constituting the reducing atmosphere (for example, a mixed gas of N ₂ and H ₂ ) is transported in the sheath 10 (in the direction of arrow A in FIG. 11). Flows in the opposite direction (the direction of arrow B in FIG. 11).

  In the firing step S107, as shown in FIG. 11, the sheaths 10 in which the plurality of ceramic molded bodies 1 are sheathed in the sheath filling step S103 are stacked in multiple stages (for example, five stages) and placed on the base plate 25. Then, the sheath 10 is conveyed into the firing furnace 20 by pushing the base plate 25 with the pusher 27. As a result, the ceramic molded body 1 is reduced and fired in a state of being placed on the mounting portion 13, and a varistor ceramic as a ceramic sintered body is obtained. The sheath 10 is placed on the base plate 25 so that the central axis direction of the placement portion 13 disposed on the sheath 10 is substantially parallel to the transport direction.

  A lid 29 is placed on the uppermost sheath 10. Specifically, the lid 29 is placed on the raised portion 46 of the frame portion 11. At this time, between the lid 29 and the portions 11a and 11b of the frame portion 11, as shown in FIG. 12A, the difference in height between the first upper surface 30 and the upper surface of the convex portion 34 ( A gap G1 having an interval corresponding to the height of the convex portion 42 and the height of the raised portion 46 is formed. Further, between the lid 29 and the portions 11c and 11d of the frame portion 11, as shown in FIG. 12B, the height difference (convexity) between the second upper surface 32 and the upper surface of the convex portion 34 is increased. A gap G2 having a distance corresponding to the height of the portion 44 and the height of the raised portion 46 is formed.

  Between the sheath 10 and the sheath 10, that is, between the portions 11a and 11b of the frame portion 11 positioned on the upper side and the portions 11a and 11b of the frame portion 11 positioned on the lower side, as shown in FIG. As shown, a gap G3 having an interval corresponding to the height difference between the first upper surface 30 and the upper surface of the convex portion 34 (height of the convex portion 42) is formed. Further, between the portions 11c and 11d of the frame portion 11 located on the upper side and the portions 11c and 11d of the frame portion 11 located on the lower side, as shown in FIG. A gap G4 having an interval corresponding to the height difference (height of the convex portion 44) between the upper surface 32 and the upper surface of the convex portion 34 is formed.

  As shown in FIG. 14, the gas constituting the reducing atmosphere (hereinafter referred to as reducing atmosphere gas) flows into the stacked sheath 10 from the front side in the transport direction through the gaps G <b> 1 to G <b> 4. Since the sheath 10 is bottomless, the reducing atmosphere gas that has flowed into the sheath 10 circulates in the space defined by the plurality of stacked sheaths 10. And the reducing atmosphere gas containing the combustion component which generate | occur | produced from the ceramic molded object 1 is mainly discharged | emitted from the gap | interval located in the conveyance direction rear side of the several sheaths 10 piled up.

  Next, the fired ceramic molded body 1 (varistor porcelain) is taken out from the sheath 10 (pod opening step: S107). In the sheath opening step S109, the mounting portion 13 is removed from the sheath 10 while being kept substantially horizontal. Although the fired ceramic molded body 1 is disposed on the mounting portion 13, it is disposed on the mounting portion 13 because a force that compresses between adjacent ceramic molded bodies 1 does not work during firing. The ceramic molded body 1 does not adhere between adjacent ones. Note that the ring-shaped varistor porcelain may be transferred to the next step in a state of being placed on the mounting portion 13.

  As described above, in the present embodiment, when a plurality of the sheaths 10 are stacked, the reducing atmosphere gas that has flowed into the stacked sheaths 10 has no bottom, with each sheath 10 (frame portion 11) forming the opening 15. Since it is in the shape, it flows so as to circulate in the inner space defined by the stacked sheaths 10. As a result, it is possible to suppress firing defects and characteristic variations.

  Moreover, since each sheath 10 (frame part 11) is bottomless, the heat capacity of the sheath 10 is small compared with a bottomed sheath. For this reason, less energy is required to obtain a desired firing temperature, and the cost of energy required for firing can be reduced.

  Moreover, in this embodiment, since the mounting part 13 is removable from the frame part 11, and is spanned over the mutually opposing parts 11a, 11b, and 11e so that it may cross the opening 15, It is possible to place the mounting portion 13 on which the ceramic molded body 1 is mounted on the frame portion 11. As a result, even if the ceramic molded body 1 is downsized, the sheathing efficiency of the ceramic molded body 1 can be improved.

  In the present embodiment, the mounting portion 13 is formed with a concave portion 70 that is concave in cross section and extends in the longitudinal direction of the mounting portion 13. Thereby, the ceramic molded body 1 can be arranged on the mounting portion 13 in a state where the ceramic molded body 1 is aligned in the thickness direction of the ceramic molded body 1 and aligned along the concave portion 70.

  Moreover, in this embodiment, the recessed parts 40 and 60 with which the mounting part 13 engages are formed in the part 11a, 11b, 13 which mutually opposes in the frame part 11. As shown in FIG. By these concave portions 40 and 60, the placement portion 13 can be reliably positioned.

  In the present embodiment, the frame portion 11 is formed with convex portions 34, 42, 44. When a plurality of the sheaths 10 are stacked, the convex portions 34, 42, and 44 cause the upper and lower sheaths 10 of the two adjacent sheaths 10 and the lower sheath 10 to move in the vertical direction (of the frame portion). Wide gaps G1 to G4 are formed in the thickness direction). Therefore, when firing the ceramic molded body 1 in the stacked sheath 10, the reducing atmosphere gas flows well into the stacked sheath 10 through the wide gaps G1 to G4. As a result, it is possible to further suppress the occurrence of defective firing and variation in characteristics.

  As a modification of the present embodiment, as shown in FIGS. 15A and 15B, a vertical wall 72 extending in a direction intersecting with the longitudinal direction of the mounting portion 13 is formed in the concave portion 70 of the mounting portion 13. It may be provided. In this case, the ceramic molded body 1 disposed in the recess 70 by the vertical wall 72 can be prevented from falling. The vertical wall 72 may be provided at both ends of the recess 70 (both ends in the longitudinal direction of the mounting portion 13) or may be provided at an intermediate portion.

  As mentioned above, although the invention made | formed by this inventor etc. was concretely demonstrated based on embodiment, this invention is not limited to the said embodiment. For example, the shapes of the ceramic molded body 1 (through hole 3) and the sheath 10 (frame portion 11) are not limited to those described above. The ceramic molded body 1 may have a disk shape in which no through hole is formed.

  In the present embodiment, the shape of the placement portion 13 is a half pipe shape, but is not limited thereto. As shown in FIGS. 16A and 16B, the recess 70 may be a groove having a vertical cross-sectional shape of, for example, a substantially V shape or a substantially rectangular shape. Further, the outer shape of the mounting portion 13 is not limited to a substantially arc shape, and the vertical cross-sectional shape may be, for example, a substantially rectangular shape as shown in FIGS. Of course, the shapes of the recesses 40 and 60 are also changed in accordance with the outer shape of the placement portion 13.

  Further, instead of forming the recesses 40 and 60 in the mutually opposite portions 11a, 11b, and 11e in the frame portion 11, a convex portion that positions the mounting portion 13 may be formed so as to sandwich the mounting portion 13. Moreover, you may bridge the mounting part 13 between the 1st part 11a and the 1st part 11b, without providing the 3rd part 11e.

  Moreover, in this embodiment, although the ceramic molded body 1 arrange | positioned in the said sheath 10 is baked, conveying the sheath 10, it is not restricted to this, The ceramic molded body 1 is conveyed without conveying the sheath 10. You may bake. Further, the flow of the reducing atmosphere gas is generated in the firing furnace 20 in the direction opposite to the direction in which the sheath 10 is conveyed. However, if the inside of the firing furnace 20 is a reducing atmosphere, the reducing atmosphere is not necessarily used. There is no need to generate a gas flow. Further, the number of stages in which the sheaths 10 are stacked is not limited to the above.

  Moreover, in this embodiment, although the inside of the baking furnace 20 was made into the reducing atmosphere, it is not restricted to this. What is necessary is just to select suitably according to the material used for the ceramic molded object 1, and air atmosphere or an inert gas atmosphere etc. may be sufficient.

  The present invention is not limited to the above-described method for manufacturing a varistor ceramic, and the same effect can be obtained when applied to a method for manufacturing a dielectric ceramic, a piezoelectric ceramic, or a semiconductor ceramic.

It is a flowchart for demonstrating the manufacturing process of the varistor porcelain which concerns on this embodiment. (A) is a top view which shows a ceramic molded body, (b) is a side view which shows a ceramic molded body. It is a perspective view which shows a sheath. It is a top view which shows a sheath. It is a perspective view which shows a sheath. It is sectional drawing along the VI-VI line in FIG. It is sectional drawing along the VII-VII line in FIG. It is a perspective view which shows the mounting part in the state by which the some ceramic molded object is arranged. It is a perspective view which shows a sheath. It is sectional drawing along the XX line in FIG. It is the schematic for demonstrating a baking furnace. (A) And (b) is a side view which shows a sheath and a lid | cover. (A) And (b) is a side view which shows the several sheath laminated | stacked. It is a schematic diagram for demonstrating the flow of reducing atmosphere gas. (A) And (b) is a perspective part which shows one modification of a mounting part. (A) And (b) is a perspective part which shows one modification of a mounting part. (A)-(c) is a perspective part which shows one modification of a mounting part.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Ceramic molded object, 11 ... Frame part, 11a, 11b ... 1st part, 11c, 11d ... 2nd part, 11e ... 3rd part, 13 ... Mounting part, 15 ... Opening, 20 ... Firing furnace , 34 ... convex part, 40 ... concave part, 42 ... convex part, 44 ... convex part, 60 ... concave part, 62 ... convex part, 70 ... concave part, 72 ... vertical wall.

Claims (5)

A frame forming an opening;
A mounting portion on which the ceramic molded body is mounted;
The above-mentioned mounting part is removable from the said frame part, and is spanned over the mutually opposing part in the said frame part so that the said opening may be crossed, The sheath for ceramic baking characterized by the above-mentioned.   2. The ceramic firing sheath according to claim 1, wherein the placement portion is formed with a recess having a concave cross section and extending in a longitudinal direction of the placement portion.   3. The ceramic firing sheath according to claim 2, wherein the concave portion is provided with a vertical wall extending in a direction intersecting with a longitudinal direction of the mounting portion.   The sheath for ceramic firing according to claim 1, wherein a concave portion that engages with the mounting portion is formed in the portions of the frame portion facing each other. 2. A sheath for ceramic firing according to claim 1, wherein a convex portion is formed on an upper surface of the frame portion.

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