JP5455678B2 - Long hollow ceramic member - Google Patents

Description

  The present invention relates to a large, long, hollow ceramic member used in a liquid crystal or semiconductor manufacturing apparatus or a precision measuring apparatus.

  In recent years, with the increase in size of liquid crystal or semiconductor manufacturing apparatuses or precision measuring apparatuses, structural parts made of ceramics used in these apparatuses, such as support members for substrates, have also been increased in size. A long ceramic member having a length exceeding 1 m may be used for the enlarged support member. Since such a large long ceramic member is heavy, it is difficult to handle, and the apparatus assembled with the long ceramic member is also difficult to convey and move due to its weight. The weight is reduced by forming a hollow portion that is continuous in the longitudinal direction at the center of the tube to form a hollow shape.

  Conventionally, an extrusion molding method has been used as a molding method for obtaining a long hollow ceramic member exceeding 1 m. The extrusion molding method is a method of continuously molding a molded body having a specific cross-sectional shape by extruding a clay, which is a molding raw material prepared in a clay shape, from a mold having a specific exit shape, This is a molding method capable of obtaining a rod-shaped or cylindrical long molded body. A long ceramic sintered body is obtained by drying and then firing the formed body obtained by this forming method. And if this long ceramic sintered compact is ground, a long ceramic member can be obtained.

  In such a long ceramic member, it is necessary not to cause cracks or bends during drying shrinkage in the drying process.

  In addition, in a long hollow ceramic member formed with a hollow portion for weight reduction, air in the hollow portion is retained in the drying step, so the vicinity of the hollow portion side of the formed body (the inner surface side of the formed body) ) Would be insufficiently dried, and there was a problem that cracks occurred in the vicinity of the surface on the hollow portion side.

  Here, FIG. 16 is a partially broken perspective view showing an example of a conventional long hollow ceramic member. The long hollow ceramic member 5 shown in FIG. 12 is a long hollow ceramic member 9 having a square outer periphery 91 of a cross section perpendicular to the longitudinal direction and a square hollow portion 92 penetrating in the longitudinal direction. is there. In FIG. 16, the four corners 93 of the long hollow ceramic member 9 are shown by hatching.

  In order to solve the problem that cracks occur in the vicinity of the surface on the hollow portion 92 side in such a long hollow ceramic member 9, Patent Document 1 discloses that the extrusion-molded body remains continuous and moves at an extrusion speed. Of the extrusion molded body so that it passes through the atmosphere of the microwave and far-infrared heater inside, and in particular, in the hollow portion, dry air is fed in parallel to the extrusion direction and the water vapor in the hollow portion is exhausted to the outside. Extrusion port is drilled on the back surface to discharge water vapor to the outside, and it prevents the water vapor from staying in the hollow part during heating and adversely affecting it. A method for producing a ceramic plate by drying and firing on a level line is disclosed. According to this, a number of exhaust ports are drilled in the back surface of the hollow portion of the extrusion molded body, and dry air or the like is supplied to the core built in the die of the extrusion molding machine to remove water vapor in the hollow portion of the extrusion molded body from the outside. By drying while evacuating, a long dry body without cracks can be obtained.

JP 63-218533 A

  However, long ceramic members that have been demanded in recent years have become larger in size, and the thickness of the long hollow ceramic member that has been hollowed in order to reduce the weight has also increased. In particular, the corner portion 93 of the long hollow ceramic member 9 is a portion that is thicker in the diagonal direction than other portions. Therefore, in the manufacturing method disclosed in Patent Document 1, the corner portion 93 is not dried. It was insufficient. Therefore, when drying progresses and the molded body shrinks by drying, there is a problem that a crack is generated near the center of the corner portion 93 that is slow to dry.

  The present invention has been devised in order to solve the problems of the prior art, and the purpose thereof is a long length that can suppress the occurrence of cracks near the center of the corner of the long hollow ceramic member. The object is to provide a hollow ceramic member.

The long hollow ceramic member of the present invention is a long hollow ceramic member having a hollow portion penetrating in the longitudinal direction, the outer periphery of the cross section perpendicular to the longitudinal direction is a polygonal shape, the outer shape of the hollow portion in the vicinity of the outer peripheral corner portion of the cross section, and is characterized in Rukoto such by calcining after drying the molded body having a groove extending in the longitudinal direction.

  Further, the long hollow ceramic member of the present invention has the above-described configuration, wherein the hollow portion is formed in a polygonal shape having an outer side parallel to the outer periphery in the cross section, and the outer corner portion of the hollow portion has an outer corner. The groove is provided.

  Further, the long hollow ceramic member of the present invention is the above-described configuration, wherein the depth of the groove is between the side of the outer corner of the hollow part where the groove is provided in the cross section and the side of the outer periphery. And the width of the groove is a distance between the other side of the outer corner of the hollow portion where the groove is provided in the cross section and the outer peripheral side. It is characterized by being not less than 1/4 and not more than 1/2.

  The long hollow ceramic member of the present invention is the shortest distance from the apex of the outer peripheral corner of the outer shape of the hollow portion, wherein the hollow portion has a circular outer shape in the cross section in the above configuration. The groove is provided in the part.

  Further, in the long hollow ceramic member of the present invention, in the above configuration, the depth of the groove is ¼ or more and ½ or less of the shortest distance between the outer shape of the hollow portion and the apex of the outer peripheral corner portion. And the width of the groove is not less than ¼ and not more than ½ of the shortest distance from the apex of the outer peripheral corner of the outer shape of the hollow portion.

  The long hollow ceramic member of the present invention is characterized in that, in each of the above structures, the arithmetic average roughness Ra of the inner surface of the groove is larger than the arithmetic average roughness Ra of the inner peripheral surface of the hollow portion. Is.

  Further, the long hollow ceramic member of the present invention, in each of the above configurations, includes a plurality of second extending in the longitudinal direction between the grooves in the vicinity of the adjacent outer peripheral corners of the cross section of the outer shape of the hollow portion. A groove is provided.

  In the long hollow ceramic member of the present invention, in the above configuration, the depth of the second groove is 1/10 or more and 1/4 or less of the thickness between the outer shape of the hollow portion and the outer periphery. The width of the second groove is not less than 1/10 and not more than 1/4 of the thickness between the outer shape of the hollow portion and the outer periphery, and the grooves at the outer peripheral corners of the outer shape of the hollow portion adjacent to each other in the cross section. The sum of the widths of the plurality of second grooves provided between the adjacent grooves is 30% to 50% of the length of the side between the adjacent outer peripheral corners.

According to the long hollow ceramic member of the present invention, it is a long hollow ceramic member having a hollow portion penetrating in the longitudinal direction, the outer periphery of the cross section perpendicular to the longitudinal direction is polygonal, and the outer shape of the hollow portion in the vicinity of the outer peripheral corner portion of the firing to such Rukoto after drying the molded body having a groove extending in the longitudinal direction, the moisture in the corner near the center of the groove is dried by evaporation is accelerated, It can suppress that a crack arises near the center of a corner | angular part.

  Further, according to the long hollow ceramic member of the present invention, the hollow part is formed in a polygonal shape having a side parallel to the outer periphery in the cross section, and extends in the longitudinal direction at the outer corner of the hollow part. When the groove is provided, drying at the outer peripheral corner of the cross section is promoted by the groove, so that the distortion generated near the center of the corner due to the difference in drying shrinkage can be reduced. Since the moisture in the vicinity of the center evaporates and drying is promoted, the occurrence of cracks in the vicinity of the center of the corner can be suppressed.

  Further, according to the long hollow ceramic member of the present invention, the depth of the groove is ¼ or more of the distance between the side of the outer corner of the hollow part provided with the groove in the cross section and the side of the outer periphery. When the width of the groove is ¼ or more and ½ or less of the distance between the other side of the outer corner of the hollow portion where the groove is provided in the cross section and the outer peripheral side. Further, drying near the center of the corner can be promoted more efficiently.

  Further, according to the long hollow ceramic member of the present invention, the outer shape of the hollow portion is formed in a circular shape in a cross section perpendicular to the longitudinal direction, and the shortest distance from the apex of the outer peripheral corner of the outer shape of the hollow portion. When a groove extending in the longitudinal direction is provided in the portion, drying at the outer peripheral corner of the cross section is promoted by the groove, and moisture near the center of the corner is evaporated from the groove to accelerate drying. It can suppress that a crack arises near the center of a part.

  According to the long hollow ceramic member of the present invention, the depth of the groove is not less than 1/4 and not more than 1/2 of the shortest distance between the outer shape of the hollow portion and the apex of the outer peripheral corner portion, and the width of the groove. However, when it is ¼ or more and ½ or less of the shortest distance between the outer shape of the hollow portion and the apex of the outer peripheral corner portion, drying near the center of the corner portion can be promoted more efficiently.

  Further, according to the long hollow ceramic member of the present invention, when the arithmetic average roughness Ra of the inner surface of the groove is larger than the arithmetic average roughness Ra of the inner peripheral surface, the surface area of the inner surface of the groove becomes larger. Further, drying near the center of the corner can be efficiently promoted, and cracks can be prevented from occurring near the center of the corner.

  Further, according to the long hollow ceramic member of the present invention, when a plurality of second grooves extending in the longitudinal direction are provided between the grooves in the vicinity of the outer peripheral corner portion of the outer cross section of the hollow portion, Drying in the vicinity of the hollow portion side is promoted, and the difference in the degree of drying between the vicinity of the hollow portion side and the vicinity of the outer peripheral side is reduced. As a result, since the distortion of the drying shrinkage of the molded product due to the difference in the degree of drying is reduced, the distortion generated near the center of the outer peripheral corner, which tends to be insufficiently dried, is also reduced, and a crack is generated near the center of the outer peripheral corner. It can be suppressed from occurring.

  According to the long hollow ceramic member of the present invention, the depth of the second groove is not less than 1/10 and not more than 1/4 of the thickness between the outer shape and the outer periphery of the hollow portion. The width of the second portion is 1/10 or more and 1/4 or less of the thickness between the outer shape and the outer periphery of the hollow portion, and a plurality of second portions provided between adjacent outer peripheral corner grooves of the cross section of the outer shape of the hollow portion. When the total width of the grooves is 30% to 50% of the length of the side between adjacent outer peripheral corners, drying of the long hollow ceramic member near the hollow portion side is efficiently promoted. The difference in the degree of drying between the vicinity of the hollow portion side and the vicinity of the outer peripheral side can be reduced. As a result, since the difference in drying shrinkage of the molded body due to the difference in the degree of drying is reduced, the stress applied to the outer peripheral corner is reduced, and it is possible to further suppress the occurrence of cracks near the center of the outer peripheral corner.

An example of embodiment of the elongate hollow ceramic member of this invention is shown, (a) is a partially broken perspective view, (b) is an enlarged view of the part enclosed with the broken line in (a). It is an expanded sectional view of the vicinity part of the outer periphery corner | angular part enclosed with the broken line in Fig.1 (a). The other example of embodiment of the elongate hollow ceramic member of this invention is shown, (a) is a partially broken perspective view, (b) is an enlarged view of the part enclosed with the broken line in (a). . FIG. 4 is an enlarged cross-sectional view of a portion in the vicinity of an outer peripheral corner portion surrounded by a broken line in FIG. The other example of embodiment of the elongate hollow ceramic member of this invention is shown, (a) is a partially broken perspective view, (b) is an enlarged view of the part enclosed with the broken line in (a). . FIG. 6 is an enlarged cross-sectional view of a portion in the vicinity of an outer peripheral corner portion surrounded by a broken line in FIG. The other example of embodiment of the elongate hollow ceramic member of this invention is shown, (a) is a partially broken perspective view, (b) is an enlarged view of the part enclosed with the broken line in (a). . FIG. 8 is an enlarged cross-sectional view of a portion in the vicinity of an outer peripheral corner portion surrounded by a broken line in FIG. (A)-(c) is principal part sectional drawing which shows the example of the cross-sectional shape of the groove | channel provided in the elongate hollow ceramic member of this invention, respectively. The other example of embodiment of the elongate hollow ceramic member of this invention is shown, (a) is a partially broken perspective view, (b) is an enlarged view of the part enclosed with the broken line in (a). . The other example of embodiment of the elongate hollow ceramic member of this invention is shown, (a) is a partially broken perspective view, (b) is an enlarged view of the part enclosed with the broken line in (a). . The other example of embodiment of the elongate hollow ceramic member of this invention is shown, (a) is a partially broken perspective view, (b) is an enlarged view of the part enclosed with the broken line in (a). . The other example of embodiment of the elongate hollow ceramic member of this invention is shown, (a) is a partially broken perspective view, (b) is an enlarged view of the part enclosed with the broken line in (a). . The example of embodiment of the elongate hollow ceramic member of this invention provided with the several hollow part penetrated in a longitudinal direction is shown, (a) is two examples in case the shape of the outer periphery of a cross section is a square shape, respectively (B) is a cross-sectional view of an example when the outer periphery shape of the cross section is a triangular shape, and (c) is a cross-sectional view of two examples when the outer periphery shape of the cross section is a pentagonal shape, respectively. It is. It is a schematic sectional drawing which shows the example of the extruder for obtaining the elongate hollow ceramic member of this invention. It is a partially broken perspective view which shows an example of the conventional elongate hollow ceramic member.

  Hereinafter, an example of an embodiment of a long hollow ceramic member of the present invention will be described with reference to the drawings.

  FIG. 1 shows an example of an embodiment of a long hollow ceramic member of the present invention, (a) is a partially broken perspective view, and (b) is an enlarged view of a portion surrounded by a broken line in (a). is there.

The long hollow ceramic member 1 of the example shown in FIGS. 1A and 1B has a quadrangular outer periphery of a cross section perpendicular to the longitudinal direction (hereinafter simply referred to as a cross section), and has a quadrangular outer shape inside. Hollow part
11 is formed. Further, in the cross section of the long hollow ceramic member 1, grooves 12 extending in the longitudinal direction are provided in the vicinity of the outer peripheral corners of the outer shape of the hollow portion 11. The cross-sectional shape of the groove 12 is a so-called U-shape having a rounded bottom. Will be described later depth _{D 1} and the width _{W 1} of the groove 12 shown in FIG. 1 (b).

  The long hollow ceramic member of the present invention is a long hollow ceramic member 1 having a hollow portion 11 penetrating in the longitudinal direction, and the outer periphery of the cross section is polygonal, and the outer cross section of the hollow portion 11 It is important that a groove 12 extending in the longitudinal direction is provided in the vicinity of the outer peripheral corner (hereinafter, the vicinity of the outer peripheral corner of the cross section is simply referred to as the vicinity of the outer peripheral corner).

  According to the long hollow ceramic member 1 of this example, the outer periphery of the cross section is polygonal, and the groove 12 extending in the longitudinal direction is provided near the outer peripheral corner of the outer shape of the hollow portion 11. Thus, solvent components such as moisture easily evaporate from the inside of the molded body in the vicinity of the center of the outer peripheral corner, and cracks can be prevented from occurring near the center of the outer peripheral corner during drying. Further, since heat is easily transmitted from the groove 12 to the entire outer peripheral corner portion even during firing, it is possible to suppress the occurrence of cracks in the outer peripheral corner portion even in the firing step. In order to promote drying near the center of the outer peripheral corner, it is preferable that the groove 12 is closer to the center of the corner. If the shape of the groove 12 in the cross section is a square shape having a flat bottom in the cross sectional shape or a shape having a corner such as a so-called V-shape in which the bottom is gradually narrowed and sharpened, the groove Since the stress tends to concentrate on the corner of 12 and the possibility of cracking at the corner increases, the bottom of the groove 12 has a curved surface like a U-shape with a rounded bottom However, it is preferable because stress concentration around the groove 12 can be reduced.

  Next, FIG. 2 is an enlarged cross-sectional view of a portion in the vicinity of the outer peripheral corner portion surrounded by a broken line in FIG.

As shown in FIG. 2, a point separated by a distance X1 on _one side of the outer periphery from the vertex O of the outer peripheral corner in the cross section of the long hollow ceramic member 1 is defined as p, and the point p passes through the point p. Among points where the YY ′ line orthogonal to a certain side intersects with the outer side of the hollow portion 11, the shortest point with the point p is defined as p ′, and the outer periphery adjacent to one side of the outer periphery where the point p is present. other from the vertex O of there corners on the sides by a distance X ₂ apart points and q, outer sides of the line Z-Z 'and a hollow portion 11 which is perpendicular to a side of through point q and the point q of Let q ′ be the shortest point between the point q and the point q.

Then, the present inventors have found that in the long hollow ceramic member 1 shown in FIG. 1, the distance X ₁ and the distance X ₂ shown in FIG. 2, the vertex of the outline and its circumference edge of the hollow portion 11 in cross-section O If the groove 12 extending in the longitudinal direction is provided within the range having the point p ′ and the point q ′ of the outer shape of the hollow portion 11 as end points, the outer periphery from the groove 12 It has been found that solvent components such as moisture easily evaporate from the inside of the molded body in the vicinity of the center of the corner, and it is possible to suppress the occurrence of cracks in the vicinity of the center of the outer peripheral corner when the molded body is dried. Therefore, in the following description, a range in which each of the point p ′ and the point q ′ of the outer shape of the hollow portion 11 is an end point is the vicinity of the outer peripheral corner of the outer shape of the hollow portion 11.

  Next, FIGS. 3 to 8 show other examples of the embodiment of the long hollow ceramic member of the present invention. In these drawings, the same reference numerals are used to denote the same parts as those in the example shown in FIG.

  FIG. 3 shows another example of the embodiment of the long hollow ceramic member of the present invention, (a) is a partially broken perspective view, and (b) is a portion surrounded by a broken line in (a). It is an enlarged view.

The long hollow ceramic member 2 of the example shown in FIG. 3 has a triangular outer periphery in cross section, and a hollow portion 11 having a triangular outer shape is formed inside. In the cross section of the long hollow ceramic member 2, there are grooves 12 extending in the longitudinal direction in the vicinity of the outer peripheral corner of the outer shape of the hollow portion 11.
Is provided.

  FIG. 4 is an enlarged cross-sectional view of the vicinity of the outer peripheral corner portion surrounded by a broken line in FIG.

Figure 4 in the vicinity portion of the outer peripheral corner part shown is the point at which distance X ₁ apart on the sides from the vertex O one of the outer periphery of the outer peripheral corner portion of the elongated hollow ceramic member 2 and p, through point the point p Of the points where the YY ′ line orthogonal to the side with p and the outer side of the hollow portion 11 intersect, the shortest point with point p is p ′, and one side of the outer periphery with point p is adjacent. fits the outer periphery of the other of there corners on the sides of the point from the vertex O distance X ₂ apart and q, of the outline of line Z-Z 'and a hollow portion 11 which is perpendicular to a side of through point q and the point q Of the points where the sides intersect, the shortest point with point q is q ′. Then, the circumference edge near the outer shape of the hollow portion 11 of the elongated hollow ceramic member 2 shown in FIG. 3, the outer shape and its outer periphery a distance X ₁ and the distance X ₂ and the hollow portion 11 in the cross section shown in FIG. 4 This is a range of the outer shape of the hollow portion 11 with the point p ′ and the point q ′ as end points when it is equal to the shortest distance X with the vertex O of the corner.

  FIG. 5 shows another example of the embodiment of the long hollow ceramic member of the present invention, (a) is a partially broken perspective view, and (b) is a portion surrounded by a broken line in (a). It is an enlarged view.

  The long hollow ceramic member 3 of the example shown in FIG. 5 has a pentagonal outer periphery in cross section, and a hollow portion 11 having a pentagonal outer shape is formed inside. In the cross section of the long hollow ceramic member 3, a groove 12 extending in the longitudinal direction is provided in the vicinity of the outer peripheral corner of the outer shape of the hollow portion 11.

  FIG. 6 is an enlarged cross-sectional view of a portion in the vicinity of the outer peripheral corner portion surrounded by a broken line in FIG.

In the vicinity of the outer peripheral corner shown in FIG. 6, a point that is a distance X1 on _one side of the outer periphery from the vertex O of the outer peripheral corner is defined as p, and Y passes through the point p and is orthogonal to the side where the point p is located. The shortest point with the point p among the points where the line YY intersects with the outer side of the hollow portion 11 is defined as p ′, and one side of the outer periphery where the point p is located is on the other side of the adjacent outer periphery. There corner from the apex O distance X ₂ apart points and q, Z-Z 'line and out point of the outer edge and crosses the point of the hollow portion 11 which is perpendicular to the sides of that point as point q q The shortest point with q is q ′. Then, the circumference edge near the outer shape of the hollow portion 11 of the elongated hollow ceramic member 3 shown in FIG. 5, the outer shape and its outer periphery a distance X ₁ and the distance X ₂ and the hollow portion 11 in the cross-section shown in FIG. 6 This is a range of the outer shape of the hollow portion 11 with the point p ′ and the point q ′ as end points when it is equal to the shortest distance X with the vertex O of the corner.

  FIG. 7 shows another example of the embodiment of the long hollow ceramic member of the present invention, (a) is a partially broken perspective view, and (b) is a portion surrounded by a broken line in (a). It is an enlarged view.

  The long hollow ceramic member 4 of the example shown in FIG. 7 has a square outer periphery in cross section, and a hollow portion 11 having a circular outer shape is formed inside. In the cross section of the long hollow ceramic member 4, grooves 12 extending in the longitudinal direction are provided in the vicinity of the outer peripheral corners of the outer shape of the hollow portion 11.

  FIG. 8 is an enlarged cross-sectional view of the vicinity of the outer peripheral corner portion surrounded by a broken line in FIG.

Also in vicinity of the outer peripheral corner portion shown in FIG. 8, the distance X ₁ away point is p on the side of the apex O one of the outer periphery of the outer peripheral corner portion, perpendicular to a side of through point p to the point p Of the points where the line YY ′ and the outer side of the hollow portion 11 intersect, the shortest point with the point p is p ′, and one side of the outer periphery where the point p is is on the other side of the adjacent outer periphery There corner from the apex O distance X ₂ apart points and q of the out of the point Z-Z perpendicular q to the side with a through point q a 'line and the outer shape of the sides of the hollow portion 11 and intersects a point The shortest point with the point q is q ′. And the elongate hollow ceramic member 4 shown in FIG.
The circumference edge near the outer shape of the hollow portion 11 in the a and the distance X ₁ and the distance X ₂ shown in FIG. 8 is equal to the shortest distance X between the apex O of the outline and its circumference edge of the hollow portion 11 in cross-section It is the range of the external shape of the hollow part 11 which has each of the point p 'and the point q' as the end point.

  As described above, in the case of the long hollow ceramic members 2 to 4 of the examples shown in FIGS. 3 to 8, as described for the long hollow ceramic member 1 shown in FIG. Since a groove 12 extending in the longitudinal direction is provided in the vicinity of the outer peripheral corner of the outer shape of the hollow portion 11 of the members 2 to 4, solvent components such as moisture near the center of the outer peripheral corner are likely to evaporate from the groove 12. Thus, it is possible to suppress the occurrence of cracks near the center of the outer peripheral corner during drying. In addition, since heat is easily transferred from the groove 12 to the entire outer peripheral corner portion even when the molded body is fired, cracks can be suppressed from occurring in the outer peripheral corner portion even in the firing step.

  Here, although the example of embodiment of the elongate hollow ceramic member of this invention was shown in FIGS. 1-8, this invention is not limited to these. As long as it does not deviate from the gist of the present invention, the shape of the outer peripheral portion in the cross section and the outer shape of the hollow portion 11 do not have to be the same, for example, triangular, quadrangular, pentagonal, hexagonal, heptagonal, From the octagonal shape or circular shape (including elliptical shape), the shape of the outer peripheral portion in the cross section and the outer shape of the hollow portion 11 are appropriately changed, or a plurality of hollow portions 11 penetrating in the longitudinal direction are provided inside, It goes without saying that improvements such as so-called chamfering that takes corners and corners of the hollow part 11 can be made.

  Further, in the long hollow ceramic member of the present invention, in the cross section, the hollow portion 11 is formed in a polygonal shape having an outer side having a side parallel to the outer periphery, and a groove 12 is provided in the outer corner of the hollow portion 11. It is preferable that

  The long hollow ceramic members 1 to 3 of the present invention shown in FIGS. 1 to 6 have a polygonal outer periphery in cross section, and the hollow portion 11 in the cross section is a polygonal shape having sides parallel to the outer periphery. If it exists, since the thickness between the hollow part 11 and the outer periphery of the long hollow ceramic members 1 to 3 can be made the same on each side, the long hollow ceramic members 1 to 3 are dried when the molded body is dried. Since the difference in the drying shrinkage of the entire molded body can be reduced on each side, the distortion generated near the center of the outer peripheral corner where the drying tends to be insufficient can be reduced. As a result, it is possible to suppress the occurrence of cracks near the center of the outer peripheral corner. Furthermore, since a groove 12 extending in the longitudinal direction is provided in the vicinity of the outer peripheral corner portion of the outer shape of the hollow portion 11, solvent components such as moisture inside the molded body near the center of the outer peripheral corner portion evaporate from the groove 12. It becomes easy to carry out, and it can suppress that a crack arises in the center vicinity of an outer periphery corner | angular part at the time of drying of a molded object. In addition, since heat is easily transferred from the groove 12 to the entire outer peripheral corner portion even when the molded body is fired, cracks can be suppressed from occurring in the outer peripheral corner portion even in the firing step.

Also, the long hollow ceramic member of the present invention, FIG. 1, FIG. 3, 5 and 7, the depth D ₁ of the groove 12, outer angle of the hollow portion 11 a groove 12 is provided in the cross section parts and 1/4 to 1/2 of the distance between the sides and the outer sides of the width W ₁ of the groove 12, the outer angle portion of the hollow portion 11 a groove 12 is provided in the cross section other It is preferable that the distance is between ¼ and ½ of the distance between the side and the outer side.

The present inventors, in order to efficiently evaporate the solvent component such as water in the vicinity of the center of the outer peripheral corner portion of the molded body of elongate hollow ceramic member 1 to 3, the depth D ₁ of the groove 12, in the cross section groove 12 is 1/4 to 1/2 of the distance between the provided hollow portion 11 outer corner edge and the outer peripheral side of the width W ₁ of the groove 12, a groove 12 is provided in the cross section It was found that the distance between the side of the outer corner of the hollow portion 11 and the other side of the outer periphery may be ¼ or more and ½ or less.

Ranges depth D ₁ is 1/4 to 1/2 of the groove 12, the width W ₁ of the groove 12 is equal to 1/2 or less of the range 1/4 or more of the above, the elongate hollow It is preferable that the evaporation rate of a solvent component such as moisture near the center of the outer peripheral corner portion from the molded body of the ceramic members 1 to 4 can be optimized, and cracks can be more effectively suppressed at the outer peripheral corner portion. .

The depth D ₁ of the groove 12 provided in the outer peripheral corner portion of the elongated hollow ceramic member 1-3 each example shown in FIGS. 1 to 6 are external angle of the hollow portion 11 in which the groove 12 is provided in the cross section If it is less than 1/4 of the distance between the parts of the side and outer peripheral side, grooves 12 becomes relatively shallow, the width W ₁ of the groove 12, the hollow portion 11 a groove 12 is provided in the cross section When the distance between the other side of the outer corner and the outer side is less than ¼, the groove 12 becomes relatively narrow, so that the moisture near the center of the outer corner that evaporates from the groove 12 There exists a tendency for the effect which suppresses that a solvent component becomes relatively few and a crack arises to reduce.

The depth D ₁ of the groove 12 provided in the outer peripheral corner portion of the elongated hollow ceramic member 1-3 each example shown in FIGS. 1 to 6 is, the hollow portion 11 in which the groove 12 is provided in the cross section becomes greater than half the distance between the outer corners of the side and the outer peripheral side, grooves 12 becomes relatively deep, the width W ₁ of the groove 12, the hollow portion 11 of the groove 12 in the cross-section is provided Since the groove 12 becomes relatively wide when the distance between the other side of the outer corner portion of the outer peripheral portion and the outer peripheral side becomes larger, the moisture near the center of the outer peripheral corner portion evaporating from the groove 12 The solvent component becomes relatively large, and the drying near the center of the outer corner becomes faster, and there is a possibility that cracking may occur due to a difference from the drying shrinkage of other parts, near the center of the outer corner. There is a tendency for the effect of suppressing cracks to be reduced.

  Further, in the long hollow ceramic member of the present invention, the hollow part 11 has a circular outer shape in cross section, and the shortest distance X from the vertex O of the outer peripheral corner of the outer shape of the hollow part 11 is formed. It is preferable that a groove 12 extending in the longitudinal direction is provided.

  The long hollow ceramic member 4 of the present invention in which the outer shape of the hollow portion 11 is formed in a circular shape in the cross section shown in FIG. 7 is a portion of the shortest distance X from the apex O of the outer peripheral corner of the outer shape of the hollow portion 11. If the groove 12 extending in the longitudinal direction is provided, the groove 12 can be provided at a position closer to the vicinity of the center of the outer peripheral corner portion, the moisture inside the molded body near the center of the outer peripheral corner portion, etc. It is possible to prevent the solvent component from evaporating easily and to prevent cracks from occurring near the center of the outer peripheral corners when the molded body is dried. In addition, since heat is easily transferred from the groove 12 to the entire outer peripheral corner portion even when the molded body is fired, cracks can be suppressed from occurring in the outer peripheral corner portion even in the firing step. Further, if the outer shape of the hollow portion 11 is formed in a circular shape so as to be inscribed in a polygon parallel to the outer peripheral side, the thickness between the hollow portion 11 and the outer periphery of the long hollow ceramic member 4 can be varied. Since the same can be made at the sides, the drying shrinkage of the entire shaped body of the long hollow ceramic member 4 can be made the same at each side of the outer periphery when the formed body is dried, and the outer periphery tends to be insufficiently dried. Distortion occurring near the center of the corner can be reduced. As a result, it is more preferable because cracks can be prevented from occurring near the center of the outer peripheral corner.

Also, the long hollow ceramic member of the present invention, in the example shown in FIGS. 7 and 8, the depth D ₁ of the groove 12, the shortest and the apex O of the outer peripheral corner portion of the outer shape of the hollow portion 11 in the cross section The distance X is ¼ or more and ½ or less of the distance X, and the width W _{1 of the} groove 12 is ¼ or more and ½ or less of the shortest distance X with the vertex O of the outer peripheral corner of the outer shape of the hollow portion 11 in the cross section. It is preferable that

In order to efficiently evaporate a solvent component such as moisture near the center of the outer peripheral corner from the formed body of the long hollow ceramic member 4, the inventor has a depth D ₁ of the groove 12 that is a hollow portion in the cross section. 11 is not less than ¼ and not more than ½ of the shortest distance X with respect to the vertex O of the outer peripheral corner of the outer shape, and the width W _{1 of the} groove 12 is the vertex O of the outer peripheral corner of the outer shape of the hollow portion 11 in the cross section. It has been found that the minimum distance X may be ¼ to ½.

The depth D1 of the groove 12 is ₁ of the shortest distance X from the apex O of the outer peripheral corner of the outer shape of the hollow portion 11 in the cross section.
/ 4 or more and ½ or less, and the width W _{1 of the} groove 12 is in the range of ¼ or more and ½ or less of the shortest distance X with the vertex O of the outer peripheral corner of the outer shape of the hollow portion 11 in the cross section. If there is, the evaporation rate of the solvent component such as moisture near the center of the outer peripheral corner from the molded body of the long hollow ceramic member 4 is optimized, and cracks are more effectively suppressed from occurring at the outer peripheral corner. This is preferable.

The depth D ₁ of the groove 12 provided in the outer peripheral corner portion of the elongated hollow ceramic member 4 of the present example, the outer angle portion of the hollow portion 11 in which the groove 12 is provided in the cross-section side and the outer periphery side and the If it is less than 1/4 of the distance between the groove 12 is relatively shallower, the width W ₁ of the groove 12, the other side and the outer periphery of the outer corner portion of the hollow portion 11 a groove 12 is provided in the cross section If the distance is less than ¼ of the distance between the groove 12 and the groove 12, the groove 12 becomes relatively narrow, so that the solvent component such as moisture near the center of the outer peripheral corner that evaporates from the groove 12 becomes relatively less. The effect of suppressing the occurrence of cracks tends to decrease.

The depth D ₁ of the groove 12 provided in a portion of the shortest distance X between the apex O of the outer peripheral corner portion of the outer shape of the hollow portion 11 of the elongated hollow ceramic member 4 of the present example, the groove 12 in the cross section becomes greater than half the distance between the provided hollow portion 11 outer corner edge and the outer peripheral side of the groove 12 is relatively deep, the width W ₁ of the groove 12, the groove 12 in the cross section Since the groove 12 becomes relatively wide when the distance between the other side of the outer corner of the hollow portion 11 provided with the hollow portion 11 and the outer peripheral side becomes larger than 1/2, the outer peripheral corner that evaporates from the groove 12 There is a possibility that cracks may occur due to a relatively large amount of water and other solvent components near the center of the surface, and drying near the center of the outer peripheral corners proceeds faster, causing a difference from the drying shrinkage of other parts. In addition, the effect of suppressing the occurrence of cracks in the vicinity of the center of the outer peripheral corner tends to decrease.

  In the long hollow ceramic member of the present invention, the arithmetic average roughness Ra which is the surface roughness of the inner surface of the groove 12 is greater than the arithmetic average roughness Ra which is the surface roughness of the inner peripheral surface of the hollow portion 11. Is also preferably large.

  1 to 8, if the surface roughness (arithmetic average roughness Ra) of the inner surface of the groove 12 is increased, the surface area of the inner surface of the groove 12 is increased. Since the solvent component such as moisture evaporates from the surface of the increased surface area, drying near the center of the outer peripheral corner of the molded body can be promoted more effectively.

  In addition to changing the surface roughness of the groove 12, the size of the surface area of the groove 12 can be changed by changing the shape of the groove 12 in the cross section of the long hollow ceramic members 1 to 4. is there. In the above example, the groove 12 has a U-shaped cross section. For example, FIGS. 9A to 9C show the shape of the groove 12 in the cross section of the long hollow ceramic member of the present invention. As shown in the sectional view of the main part, the square shape of the example shown in FIG. 9A, the V shape of the example shown in FIG. 9B, or the V shape of the example shown in FIG. 9C. A shape having a flat bottom surface at the bottom of the shape may be appropriately selected and employed. 9A to 9C are cross-sectional views of the main part, but hatching applied to each cross section is omitted.

  Next, FIG. 10 shows another example of the embodiment of the long hollow ceramic member of the present invention, (a) is a partially broken perspective view, and (b) is surrounded by a broken line in (a). It is an enlarged view of the part. In addition, when showing the site | part common to the example shown in FIG. 1, it shows using the same referential mark.

The long hollow ceramic member 5 of the example shown in FIG. 10 has a square outer periphery in cross section, and a hollow portion 11 having a rectangular outer shape formed therein. In the cross section of the long hollow ceramic member 5, grooves 12 extending in the longitudinal direction are provided in the vicinity of the outer peripheral corners of the outer shape of the hollow portion 11. A plurality of second grooves 14 extending in the longitudinal direction are provided between the grooves 12. The depth D ₂ and width W _{2 of the} groove 14 shown in FIG. 10B and the side length W ₃ between adjacent outer peripheral corners will be described later.

  In the long hollow ceramic member of this example, a plurality of second grooves 14 extending in the longitudinal direction are provided between the grooves 12 in the vicinity of the adjacent outer peripheral corners of the outer cross section of the hollow portion 11. It is preferable.

  According to the long hollow ceramic member 5 of this example, a plurality of second grooves 14 extending in the longitudinal direction are provided between the grooves 12 in the vicinity of the adjacent outer peripheral corners of the outer cross section of the hollow portion 11. Therefore, when the molded body is dried, the solvent component such as moisture evaporates from the second groove 14, so that drying near the hollow portion side of the molded body is promoted, and drying near the hollow portion side and near the outer peripheral side are promoted. The difference in the degree of drying with is small. As a result, since the distortion of the drying shrinkage of the molded product due to the difference in the degree of drying is reduced, the distortion generated near the center of the outer peripheral corner, which tends to be insufficiently dried, is also reduced, and a crack is generated near the center of the outer peripheral corner. Generation | occurrence | production can further be suppressed. Further, if the thickness of the long hollow ceramic member is increased, it takes time to fire the compact in the firing step. However, according to the long hollow ceramic member 5 of this example, the compact is formed from the second groove 14. Since heat is easily transmitted to the entire body, the firing time can be shortened.

  Further, the shape of the second groove 14 in the cross section is preferably such that the bottom of the second groove 14 is a curved surface as in the U-shape because stress concentration around the second groove 14 can be reduced. .

  Next, FIG. 11 to FIG. 13 show the long hollow ceramic member of the present invention, and a plurality of members extending in the longitudinal direction between the grooves 12 in the vicinity of the adjacent outer peripheral corners of the cross section of the outer shape of the hollow portion 11. Another example in which the second groove 14 is provided is shown. In these drawings, the same reference numerals are used to denote the same parts as those in the example shown in FIG.

  FIG. 11 shows another example of the embodiment of the long hollow ceramic member of the present invention, (a) is a partially broken perspective view, and (b) is a portion surrounded by a broken line in (a). It is an enlarged view.

  The long hollow ceramic member 6 of the example shown in FIG. 11 has a square outer periphery in cross section, and a hollow portion 11 having a triangular outer shape formed therein. In the cross section of the long hollow ceramic member 6, a groove 12 extending in the longitudinal direction is provided in the vicinity of the outer peripheral corner of the outer shape of the hollow portion 11. A plurality of second grooves 14 extending in the longitudinal direction are provided between the adjacent grooves 12.

  FIG. 12 shows another example of the embodiment of the long hollow ceramic member of the present invention, (a) is a partially broken perspective view, and (b) is a portion surrounded by a broken line in (a). It is an enlarged view.

  The long hollow ceramic member 7 of the example shown in FIG. 12 has a pentagonal outer periphery in cross section, and a hollow portion 11 having a triangular outer shape is formed inside. In the cross section of the long hollow ceramic member 7, grooves 12 extending in the longitudinal direction are provided in the vicinity of the outer peripheral corners of the outer shape of the hollow portion 11. A plurality of second grooves 14 extending in the longitudinal direction are provided between the adjacent grooves 12.

  FIG. 13 shows another example of the embodiment of the long hollow ceramic member of the present invention, (a) is a partially broken perspective view, and (b) is a portion surrounded by a broken line in (a). It is an enlarged view.

  The long hollow ceramic member 8 of the example shown in FIG. 13 has a square outer periphery in cross section, and a hollow portion 11 having a circular outer shape formed therein. In the cross section of the long hollow ceramic member 8, grooves 12 extending in the longitudinal direction are provided in the vicinity of the outer peripheral corner of the outer shape of the hollow portion 11, respectively. A plurality of second grooves 14 extending in the longitudinal direction are provided between the adjacent grooves 12.

  In this way, in the case of the long hollow ceramic members 6 to 8 of the examples shown in FIGS. 11 to 13, the long hollow ceramic member 5 of the example shown in FIG. Since the plurality of second grooves 14 extending in the longitudinal direction are provided between the grooves 12 at the adjacent outer peripheral corners of the hollow portions 11 of the shaped ceramic members 6 to 8, the second portion 14 is dried when the molded body is dried. Since the solvent component such as moisture evaporates from the groove 14 of the groove, drying near the hollow portion side of the molded body that is difficult to dry is promoted, and the difference in the degree of drying between the drying near the hollow portion side and the vicinity of the outer peripheral side becomes small. . As a result, since the distortion of the drying shrinkage of the molded product due to the difference in the degree of drying is reduced, the strain applied near the center of the outer corner where the drying tends to be insufficient is also reduced, and there is a crack near the center of the outer corner. Generation | occurrence | production can further be suppressed. Further, if the thickness of the long hollow ceramic member is increased, it takes time to fire the compact in the firing step. However, according to the long hollow ceramic members 6 to 8 of this example, the second groove 14 is used. Since heat is easily transmitted to the entire molded body, the firing time can be shortened.

Further, in the long hollow ceramic member of the present invention, the depth D2 of the _second groove 14 shown in FIGS. 10 to 13 is 1/10 or more of the thickness between the outer shape and the outer periphery of the hollow portion 11. / 4 or less, and the width W2 of the _second groove 14 is 1/10 or more and 1/4 or less of the thickness between the outer shape and the outer periphery of the hollow portion 11, and the cross-sections of the outer shape of the hollow portion 11 are adjacent to each other. it is preferred the edge between the outer peripheral corner portion of the total width W ₂ of the second groove 14 of a plurality provided between the outer peripheral corner portion adjacent it is 30% to 50% of the length W _3. The length W ₃ of the edge between the outer peripheral corner portion adjacent, as shown in FIG. 10 (b) ~ FIG 12 (b), between the intersection of the extension line of the outer shape of the side of the hollow portion 11 in the cross section Indicates the distance. Further, in the case of a long hollow ceramic member 8 in which the outer shape of the hollow portion 11 is not polygonal in cross section, like the long hollow ceramic member 4 of the example shown in FIG. As shown, in the outer shape of the hollow portion 11 in the cross section, the hollow portion 11 between the shortest point with the vertex O of the outer peripheral corner and the shortest point with the vertex O of the other outer peripheral corner is adjacent. the distance of the shortest along the outer shape may be the side length W ₃ between the outer peripheral corner adjacent.

In order to efficiently promote drying in the vicinity of the hollow portion side of the molded body in the long hollow ceramic members 5 to 8, the present inventor has a depth of the second groove 14 which is the outer shape of the hollow portion 11. The thickness between the outer periphery is 1/10 or more and 1/4 or less, and the width W2 of the _second groove 14 is 1/10 or more and 1/4 or less of the thickness between the outer shape of the hollow portion 11 and the outer periphery. There, the edge between the outer peripheral corner portion of the total width W ₂ of the second groove 14 of a plurality provided between the outer peripheral corner portion adjacent the cross section of the outer shape of the hollow portion 11 adjacent the length W ₃ It has been found that 30% to 50% is sufficient.

The depth D2 of the _second groove 14 is 1/10 or more and 1/4 or less of the thickness between the outer shape and the outer periphery of the hollow portion 11, and the width W2 of the _second groove 14 is the outer shape of the hollow portion 11. The width W ₂ of the plurality of second grooves 14 provided between adjacent outer peripheral corners of the cross section of the outer shape of the hollow portion 11 is 1/10 or more and ¼ or less of the thickness between the outer periphery and the outer periphery. if the length range of 30% to 50% of W ₃ sides between the outer peripheral corner portions total adjacent such as moisture from the vicinity of the hollow portion of the molded body elongated hollow ceramic member 5-8 It is preferable because the evaporation rate of the solvent component can be optimized to prevent the occurrence of cracks at the outer peripheral corners more effectively.

The depth D2 of the _second groove 14 provided in the long hollow ceramic member 5-8 of each example shown in FIGS. 10 to 13 is 1/10 of the thickness between the outer shape and the outer periphery of the hollow portion 11. If the width is less than 2, the second groove 14 becomes relatively shallow, and if the width W2 of the _second groove 14 is less than 1/10 of the thickness between the outer shape and the outer periphery of the hollow portion 11, the groove 12 Is relatively narrow, so that the solvent component such as moisture near the hollow portion side of the molded body evaporating from the second groove 14 is relatively reduced, and drying near the hollow portion side and drying near the outer peripheral side are performed. There is a tendency that the effect of suppressing the occurrence of cracks near the center of the outer peripheral corner portion is reduced.

Moreover, the 2nd groove | channel provided in the long hollow ceramic members 5-8 of each example shown in FIGS.
When the depth D ₂ of 14 is greater than 1/4 of the thickness between the outline and the periphery of the hollow portion 11, the second groove 14 is relatively deep, the width W ₂ of the second groove 14 is hollow When the thickness is larger than ¼ of the thickness between the outer shape and the outer periphery of the portion 11, the second groove 14 becomes relatively wide, so that the moisture around the center of the outer peripheral corner portion evaporating from the second groove 14 is increased. The solvent component becomes relatively large, and the drying near the hollow portion side of the molded body proceeds faster than the outer peripheral side, and the effect of suppressing the occurrence of cracks near the center of the outer peripheral corner tends to decrease. .

Further, the depth D2 of the _second groove 14 provided in the long hollow ceramic members 5 to 8 of each example shown in FIGS. 10 to 13 is 1 of the thickness between the outer shape and the outer periphery of the hollow portion 11. When the width W2 of the _second groove 14 is 1/10 or more and 1/4 or less of the thickness between the outer shape and the outer periphery of the hollow portion 11, the outer shape of the hollow portion 11 If the sides of less than 30% of the length W ₃ of between circumference edge of the total width W ₂ of the plurality of second grooves 14 adjacent which is provided between the outer peripheral corner portion adjacent the cross-section, Solvent components such as moisture in the vicinity of the hollow portion side of the molded body evaporating from each of the plurality of second grooves 14 provided between adjacent outer peripheral corner portions of the outer cross section of the hollow portion 11 are relatively reduced. However, the difference in the degree of drying between the vicinity of the hollow portion and the vicinity of the outer peripheral side is not so small, and the effect of suppressing the occurrence of cracks near the center of the outer peripheral corner tends to decrease. .

Conversely, the edge between the outer peripheral corner portion of the total width W ₂ of the second groove 14 of a plurality provided between the outer peripheral corner portion adjacent the cross section of the outer shape of the hollow portion 11 is adjacent length When it is 50% or more of W ₃ , moisture near the hollow portion side of the molded body evaporating from each of the plurality of second grooves 14 provided between adjacent outer peripheral corner portions of the outer cross section of the hollow portion 11, etc. So that the difference in the degree of drying between the vicinity of the hollow part and the vicinity of the outer peripheral side is not so small, and the drying near the hollow part side of the molded body proceeds faster than the outer peripheral side. Therefore, the effect of suppressing the occurrence of cracks near the center of the outer peripheral corner tends to decrease.

  A plurality of second grooves 14 provided between adjacent outer peripheral corners of the outer cross section of the hollow portion 11 of the long hollow ceramic members 5 to 8 of each example shown in FIGS. It is preferable that they are arranged at equal intervals.

  If the plurality of second grooves 14 provided between the adjacent outer peripheral corners of the cross section of the outer shape of the hollow portion 11 of the long hollow ceramic members 5 to 8 are arranged at equal intervals, a plurality of second grooves 14 are provided. The solvent component such as moisture in the vicinity of the hollow portion of the molded body provided with the two grooves 14 can be evaporated without unevenness, and the distortion of drying shrinkage of the molded body due to the difference in the degree of drying can be further reduced. It is possible to further suppress the occurrence of cracks near the center of the corner.

Further, a plurality of second grooves 14 provided between adjacent outer peripheral corners of the cross section of the outer shape of the hollow portion 11 of the long hollow ceramic members 5 to 8 of each example shown in FIGS. The distance between the adjacent second grooves 14 is preferably at least ½ of the depth D2 of the _second grooves 14. In the case where the depth D ₂ of the second groove 14 adjacent are different, the distance between the second groove 14 adjacent to the deeper towards the second groove 14 of depth D ₂ 1 / Two or more are preferable.

Adjacent of a plurality of second grooves 14 provided between adjacent outer peripheral corners of the cross section of the outer shape of the hollow portion 11 of each of the long hollow ceramic members 5 to 8 shown in FIGS. 10 to 13. the distance between the second groove 14, as long as 1/2 or more the depth D ₂ of the second groove 14, a plurality of second grooves 14, the distance between the second groove 14 adjacent to Therefore, when the plurality of second grooves 14 are provided by cutting or the like, the portion between the second grooves 14 is less likely to be twisted. Further, when bending stress or the like is applied, stress tends to concentrate on the outer peripheral corner, so it is better to secure a sufficient distance between the groove 12 and the second groove 14 adjacent to the groove 12. Preferably, the groove 12, the groove 12 the distance between the second groove 14 adjacent to the, if the depth D ₁ or more grooves 12, enough strength of the long hollow ceramic member 5-8 It can be secured.

  Next, the example at the time of providing a some hollow part about the elongate hollow ceramic member of this invention is demonstrated.

  FIG. 14 shows the shape of the outer periphery and the hollow part in the example of the embodiment of the long hollow ceramic member of the present invention provided with a plurality of hollow parts penetrating in the longitudinal direction. It is sectional drawing of two examples in the case of a shape, (b) is sectional drawing of the example in case the shape of the outer periphery of a cross section is a triangle shape, (c) is a case where the shape of the outer periphery of a cross section is a pentagon shape, respectively It is sectional drawing of these two examples.

FIG. 14 (a), the shape of the outer periphery of the cross section in the case of a square shape is shown a plurality of hollow portions 11 elongated hollow ceramic member in the example provided is A ₁ and A _2. These hollow portions 11 include all the hollow portions 11 and are formed so that each side of the rectangular outer shape 62 having a minimum area is parallel to each side of the outer periphery. Incidentally, the long hollow ceramic member A ₂ is an outer peripheral is a square shape, so that the hollow portion 11 of the outer shape of the elliptical shape is included in the rectangular outer shape 62 having sides parallel to respective sides of the outer periphery Two are provided.

  Next, the example shown in FIG. 14B is a cross-sectional view showing a long hollow ceramic member B of an example in which a plurality of hollow portions 11 are provided when the outer periphery of the cross section is triangular. The hollow portion 11 is formed so as to include all the hollow portions 11 and to have each side of the triangular outer shape 62 having the smallest area parallel to each side of the outer periphery.

  In the case of the long hollow ceramic member B of the example shown in FIG. 14 (b), the outer periphery has a triangular shape, and the hollow portion 11 having a triangular outer shape has a triangular shape having each side parallel to each side of the outer periphery. Two are provided so as to be included in the outer shape 62 of the above.

Next, the example shown in FIG. 14C is a cross section showing the long hollow ceramic members C ₁ and C ₂ of the example in which a plurality of hollow portions 11 are provided when the outer periphery of the cross section is a pentagon. FIG. These hollow portions 11 include all the hollow portions 11 and are formed so that each side of a pentagonal outer shape 62 having a minimum area is parallel to each side of the outer periphery. Incidentally, the long hollow ceramic member C ₂ is the outer circumference is pentagonal, so that the hollow portion 11 of the circular outer shape, enclosed in the pentagonal profile 62 having sides parallel to respective sides of the outer periphery In addition, a total of six are provided, one at each corner of the outer shape 62 and one at the center.

As in these examples, a plurality of hollows penetrating in the longitudinal direction are arranged in a long hollow ceramic member so as to be included in a polygonal outer shape 62 having sides parallel to each side of the outer periphery of the polygonal shape. By providing the portion 11, the ceramic portion between the hollow portion 11 and the hollow portion 11 becomes the reinforcing portion 61, and the long hollow ceramic members A ₁ , A ₂ , B, C with enhanced bending strength in the longitudinal direction. ₁ and C ₂ can be obtained.

In the long hollow ceramic members A ₁ , A ₂ , B, C ₁ and C _{2 of} the present example provided with a plurality of hollow portions 11 in this way, all the hollow portions 11 are included in the cross section and the minimum area is obtained. The hollow portions 11 are formed by arranging the sides of the polygonal outer shape 62 having a parallel to the sides of the outer periphery, and the grooves 12 extending in the longitudinal direction are provided at the outer peripheral corners. If the hollow portion 11 is formed in this way, the variation in thickness between the hollow portion 11 and the outer periphery of the long hollow ceramic member can be reduced, so that the vicinity of the center of the outer peripheral corner portion can be reduced during drying shrinkage of the molded body. In addition, since the solvent component such as moisture near the center of the outer peripheral corner from the groove 12 is likely to evaporate from the groove 12, cracks are generated near the center of the outer peripheral corner when the molded body is dried. Can be suppressed.

In the long hollow ceramic member of the present invention, the depth direction of the groove 12 may not be perpendicular to the outer peripheral surface on which the groove 12 is provided.

  Further, in the long hollow ceramic member of the present invention, the groove 12 provided in the vicinity of the outer peripheral corner portion of the outer shape of the hollow portion 11 does not necessarily have to be provided in the vicinity of all the outer peripheral corner portions, and cracks are generated in the outer peripheral corner portion. Accordingly, it may be provided at one or more in the vicinity of the outer peripheral corner of the outer shape of the hollow portion 11.

The long hollow ceramic member of the present invention is shown in FIGS. 1, 3, 5 and 7 in order to meet the demand for long, high strength and light weight, which is required for increasing the size of structural parts. The present invention can be suitably applied to a case where the length L is 0.5 m or more and the thickness t for maintaining the strength with the hollow portion 11 is 10 mm or more and 40 mm or less.

  Moreover, oxide ceramics such as alumina and zirconia, or non-oxide ceramics such as silicon nitride and silicon carbide can be applied to the ceramic used for the long hollow ceramic member of the present invention. In particular, it has good corrosion resistance against chemicals and corrosive gases used in liquid crystal and semiconductor manufacturing processes and precision measurement, and has moderate mechanical strength and is inexpensive compared to other ceramic materials. It is preferable to use certain alumina ceramics.

  Next, the manufacturing method of the elongate hollow ceramic member of this invention is demonstrated.

  FIG. 15 is a schematic sectional view showing an example of an extruder for obtaining a long hollow ceramic member of the present invention.

  A screw-type extrusion molding machine 80 shown in FIG. 15 includes a clay inlet 82 and a bag mill 81 having a bag screw 83 for kneading the clay, and a vacuum chamber 84 for evacuating and discharging bubbles in the clay. The auger part 85 having an auger screw 86 for extruding the clay, a clay rectification part 88 provided with a plurality of rectifying springs that divide the clay, and a clay shearing part 89 are provided to make the clay into a specific shape. It consists of an extrusion mold part 87 to be molded.

  Although not shown, one of the pug screw 83 and the auger screw 86 is connected and fixed to a bearing, and is connected to a power source. Furthermore, a vacuum pump (not shown) for evacuating the inside of the vacuum chamber 84 is connected.

  In the manufacturing method of the long hollow ceramic member of the present invention using this extruder 80, a ceramic material mainly composed of an alumina raw material, a binder and a solvent are mixed to form a clay, and this clay is converted into a plurality of rectifiers. Extrusion molding was performed using a screw-type extruder 80 having a clay rectification unit 88 provided with a radial shape and a clay shearing unit 89 for obtaining a long hollow molded body, and the obtained long The hollow molded body is fired.

  Next, the detail of the manufacturing method of the elongate hollow ceramic member of this invention is demonstrated.

First, as the alumina raw material, a commercially available α-alumina raw material that is widely used as an industrial product, preferably having a purity of 99.5% or more and an average particle diameter of 1 μm to 3 μm, and a soda component (Na ₂ O) If it is 0.1% by mass or less, the soda component (N
There is little concern that a ₂ O) will scatter and contaminate the inside of the firing furnace, and it is still preferable. Here, the average particle diameter of the alumina raw material represents a 50% particle diameter D ₅₀ measured by a laser diffraction particle size distribution measuring method. As the sintering aid, for example, magnesia (MgO), silica (SiO ₂ ), calcia (CaO) or the like is used. The total amount of addition of the sintering aid may be 5% by mass or less so that the alumina purity of the alumina sintered body is 95% by mass or more in order to increase the rigidity of the sintered body. The alumina raw material and the sintering aid may be mixed with a solvent such as water to form a slurry and granulated into granules by a spray drying method (spray drying).

As the binder, methyl cellulose (MC), carboxymethyl cellulose (CMC), hydroxypropyl cellulose (HPC), polyvinyl alcohol (PVA), polyvinyl butyral (PVB) and the like generally used for extrusion molding clays are used. The total amount of binder added can be determined by adding 2 parts by weight or more and 8 parts by weight or less in solid content to 100 parts by weight of ceramic material containing alumina raw material and sintering aid. Good shape retention. Furthermore, as a lubricant, wax, glycerin, stearic acid or the like may be appropriately added in an amount of 1 part by mass or more and 8 parts by mass or less in terms of solid content. Further, water is preferable as the solvent, and ion-exchanged water is particularly preferable because the amount of impurities is small. Then, a ceramic material containing a sintering aid mainly composed of an alumina raw material, a binder, and a solvent are weighed and mixed, and then kneaded using a universal mixer or a three-roller. By this kneading, the surface of the ceramic material made of the alumina raw material and the sintering aid is uniformly wrapped with a binder and a solvent, and a plastic clay is obtained.

  Next, this clay is introduced from the clay inlet 82 of the extrusion molding machine 80. The introduced clay is kneaded by the rotation of the pag screw 83 and pushed out to the vacuum chamber 84 through the gap between the pag screw 83 and the inner wall of the pag mill 81. The forming raw material extruded into the vacuum chamber 84 is discharged from the internal bubbles by a vacuum pump connected to the vacuum chamber 84. Thereafter, the auger screw 86 is rotated and pushed out through the gap between the auger screw 86 and the auger part 85 in the direction of the extrusion mold part 87.

  The extrusion die portion 87 is provided with a convex portion corresponding to the cross-sectional shape of the groove 12 at a position corresponding to the vicinity of the outer peripheral corner portion of the outer shape of the hollow portion 11 in the long hollow ceramic member of the present invention. By the convex portion provided in the extrusion mold portion 87, the groove 12 extending in the longitudinal direction can be provided in the vicinity of the outer peripheral corner portion of the outer shape of the hollow portion 11 of the hollow molded body. As in the case of the long hollow ceramic members 5 to 8, a plurality of second grooves 14 extending in the longitudinal direction are provided between the grooves 12 in the vicinity of the adjacent outer peripheral corners of the outer cross section of the hollow portion 11. For this purpose, a protrusion may be provided at a position corresponding to the second groove 14 of the extrusion mold part 87.

  Further, if the surface roughness of the convex portion is made larger than the surface roughness of the extrusion die portion 87 corresponding to the inner peripheral surface of the hollow portion 11 of the long hollow ceramic member of the present invention, the surface of the inner surface of the groove 12 The roughness (arithmetic average roughness Ra) can be made larger than the surface roughness (arithmetic average roughness Ra) of the inner peripheral surface of the hollow portion 11. In addition, you may adjust the surface roughness (arithmetic average roughness Ra) of the inner surface of a groove | channel using a small sandblast apparatus after extrusion molding.

  The arithmetic average roughness Ra of the inner surface of the groove 12 and the arithmetic average roughness Ra of the inner peripheral surface of the hollow portion 11 are determined according to JIS standards (JIS B 0601: 2001) using a surface shape measuring instrument, for example, It can be measured under the measurement conditions of a needle tip radius of curvature of 5 μm, a cutoff value of 0.8 mm, an evaluation length of 4 mm, and a speed of 0.1 mm / s. In addition, as the measurement sites, five sites in the longitudinal direction of the long hollow ceramic member are selected as the measurement sites, and the arithmetic average roughness Ra of the inner surface of the groove 12 and the inner peripheral surface of the hollow portion 11 in each measurement site. Is measured once, and the average value of the measured values at the five sites may be the arithmetic average roughness Ra of the inner surface of the groove 12 and the inner peripheral surface of the hollow portion 11. If the width of the groove 12 is small or the depth is so deep that the tip of the stylus cannot be measured because it does not contact the groove 12, synthetic rubber (eg, silicone rubber) or synthetic resin is used. Alternatively, a replica in which the surface state of the groove 12 is transferred may be prepared, and the arithmetic average roughness Ra of the portion of the replica in which the surface state of the groove 12 is transferred may be measured.

Next, the molded body of the long hollow ceramic member obtained by extrusion molding is put in a dryer, and dried by raising the temperature gradually from 20 ° C. near room temperature to near 80 ° C. in an air atmosphere. Thereafter, firing is performed at a firing temperature of 1550 ° C. or higher and 1650 ° C. or lower using a firing furnace in an air atmosphere according to the purity of the alumina raw material and the type of sintering aid.

  Finally, a long hollow ceramic member is obtained by finishing the obtained sintered body so as to have a desired dimension.

  Further, in this finishing process, a metal plate or ceramic plate having a shape corresponding to the shape of the groove 12 provided in the long hollow ceramic member is fitted into the groove 12 and bonded with an adhesive to form the long hollow ceramic member. The long hollow ceramic member may be reinforced by reinforcing or filling the groove 12 with a photocurable resin and irradiating it with light.

In the case of the long hollow ceramic members 1 to 3, the groove 12 extending in the longitudinal direction is provided in the vicinity of the outer peripheral corner of the outer shape of the hollow portion 11 of the long hollow ceramic members 1 to 4 by the manufacturing method as described above. preferably the depth D ₁ of the groove 12, groove 12 and provided with a hollow portion 11 outer corner edge and the outer peripheral side of 1/4 to 1/2 of the distance between the in cross-section, the groove the width W ₁ of 12, and 1/4 to 1/2 of the distance between the other side and the outer peripheral side of the outer corner portion of the hollow portion 11 a groove 12 is provided in the cross section, elongated hollow In the case of the ceramic member 4, the depth D ₁ of the groove 12 is ¼ or more and ½ or less of the shortest distance X with the vertex O of the outer peripheral corner of the outer shape of the hollow portion 11 in the cross section, and the width of the groove 12. By setting W ₁ to be not less than ¼ and not more than ½ of the shortest distance X with the vertex O of the outer peripheral corner portion of the outer shape of the hollow portion 11 in the cross section, the long hollow sera Solvent components such as moisture evaporate from the grooves 12 installed at the corners of the outer periphery in the drying process of the molded body of the Mic member, drying near the center of the corners of the outer periphery of the molded body is accelerated, and the long hollow during drying It is possible to obtain long hollow ceramic members 1 to 4 by suppressing the occurrence of cracks in the vicinity of the center of the outer peripheral corner due to drying shrinkage of the shaped ceramic member.

  Examples of the present invention will be specifically described below, but the present invention is not limited to these examples.

  The long hollow ceramic member of the present invention and the conventional long hollow ceramic member are manufactured using the same manufacturing process, and cracks are caused by drying shrinkage near the center of the outer peripheral corner of the long hollow ceramic member. A test was conducted to confirm whether or not Hereinafter, details and results of the test will be described.

Example 1
First, the total amount of sintering aid including 96% by mass of low-soda α-alumina material having a purity of 99.8% alumina raw material and 0.05% by mass soda component (Na ₂ O), and magnesia, calcia and silica 4 parts by mass to 100 parts by mass, and 100 parts by mass of the mixed ceramic material, 4 parts by mass of methyl cellulose for binder, 2 parts by mass of polyvinyl alcohol, and 2 parts by mass of wax for lubricant And 14 parts by mass of ion-exchanged water were weighed and mixed, and further kneaded by a three-roll mill to obtain a clay for extrusion molding.

Using the produced clay, extrusion molding is performed by an extruder 80 shown in FIG. 11, and the shape of the long hollow ceramic member 1 in the example shown in FIG. 1 is 10 mm in thickness t, 1 m in length L, width 65 mm, made height and external dimensions of 65 mm, when equal respectively to the shortest distance X in Figure 2 the value of the distance X ₁ or the distance X ₂ and the outer shape of the hollow portion 11 and the apex O of the circumference edge, A molded product No. 1 having a groove 12 provided so that the center line of the groove 12 passes through the point p ′ or the point q ′. 30 each of 1 and 2 were produced. In addition, compact No. Grooves 12 of 1 and 2 were the width _{W 1} and 5mm all depth _{D 1} so as to be 3 mm. In addition, the outer side of the hollow portion 11 provided with the groove 12 and the groove 12 are perpendicularly crossed.

Next, the molded body No. As shown in FIG. 2, the molded body No. 1 was provided with a groove 12 at the shortest distance X from the apex O of the outer peripheral corner of the outer shape of the hollow portion 11. 30 3 were produced. In addition, as a material outside the scope of the present invention, the molded product No. In the same outer dimensions as 1 and 2, when equal respectively to the shortest distance X + 2 mm in 2 values of the distance X ₁ or the distance X ₂ and the outer shape of the hollow portion 11 and the apex O of the circumference edge, the point p 'or The molded body No. 1 provided with the groove 12 so that the center line of the groove 12 passes through the point q ′. 30 each of 4 and 5 were produced. In addition, compact No. Grooves 12 of 1 and 2 were the width _{W 1} and 5mm all depth _{D 1} so as to be 3 mm. In addition, the outer side of the hollow portion 11 provided with the groove 12 and the groove 12 are perpendicularly crossed.

  Then, the molded body No. 1 to 5 was gradually heated from 20 ° C. to near 80 ° C. and dried, and the number of non-defective products was confirmed by taking a molded product in which no crack occurred near the center of the outer peripheral corner as a good product.

  In addition, the molded body No. 1 of the comparative example, which has the same external dimensions as the long hollow ceramic member 1 and becomes a conventional long hollow ceramic member without the groove 12, is used. 30 pieces of 6 were prepared and dried under the same conditions. Then, the formed compact No. 20 were randomly selected from 1 to 6, and the number of non-defective products was confirmed. For confirmation, each molded body No. 1-6 were cut | disconnected several places perpendicularly to the longitudinal direction, and the presence or absence of the crack near the center of an outer periphery corner | angular part was investigated visually.

  As a result, the molded product No. of Example of the present invention. Nos. 1 to 3 are molded body Nos. There were more non-defective products than six. In particular, the compact No. No. 3 had the highest number of good products, and good results were obtained. Further, the sample molded body No. 4 and 5 and the molded body No. In 6 there was no difference in the results.

  Further, the remaining dry molded body No. 1 to 3 and 6 were fired at a temperature of 1600 ° C. using a firing furnace in an air atmosphere to produce a sintered body. Similarly to 1 to 3 and 6, a plurality of places were cut perpendicular to the longitudinal direction, and the presence or absence of cracks near the center of the outer peripheral corner was visually confirmed.

  As a result, the long hollow ceramic member 1 of the example of the present invention had more non-defective products than the long hollow ceramic member of the comparative example having the same dimensions.

  Similar tests were performed on the shapes of the long hollow ceramic members 2 to 4 in the examples shown in FIGS. 3, 5, and 7, and the results were the same. Both the drying step and the firing step were the lengths of the examples of the present invention. The number of non-defective products was higher in the hollow hollow ceramic member than in the comparative example. Similarly, as shown in FIGS. 4, 6, and 8, in the molded body in which the groove 12 is provided in the portion of the shortest distance X from the vertex O of the outer peripheral corner of the outer shape of the hollow portion 11 and the sintered body thereof The number of non-defective products was the largest, and good results were obtained. Further, this result is that the molded body No. 1 having the same shape as the long hollow ceramic member 4 shown in FIG. 3 was remarkable. Further, there was no difference in the results between the sample molded body outside the scope of the present invention and the molded body of the comparative example.

  From this result, it was found that the long hollow ceramic member of the present invention can suppress the occurrence of cracks in the vicinity of the center of the outer peripheral corner as compared with the conventional long hollow ceramic member.

(Example 2)
Next, a test was performed to check whether the thickness variation between the hollow portion 11 of the long hollow ceramic member and the outer periphery affects cracks generated near the center of the outer peripheral corner portion.

Using the clay prepared in Example 1, the shape of the long hollow ceramic member 1 of the example shown in FIG. 1 has an external dimension of a length L of 1 m, a width of 65 mm, a height of 65 mm, and a thickness t In the cross section, the hollow portion 11 is formed in a polygonal shape having sides parallel to the outer periphery so that the molded body No. 3 the depth D ₁ at the same position to produce twenty by extrusion molding a molded body M of the embodiment comprising an elongated hollow ceramic member having a width W ₁ is provided with a groove 12 of 3mm in 5 mm, as in Example 1 The product was dried under the same conditions, and the number of good products of the molded product M was confirmed. Further, the molded body M has the same shape and the same outer dimensions, and is hollow so that the tolerance of the distance between the outer peripheral side and the outer side of the hollow portion 11 in the cross section is ± 4 mm and the average value of the thickness t is 10 mm. Twenty comparative molded bodies N, which are long hollow ceramic members provided with the portion 11, were produced and dried under the same conditions as in Example 1, and the number of non-defective products of the molded body N was confirmed.

  As a result, the number of non-defective products of the molded body M of the example was larger than the number of non-defective products of the molded body N of the comparative example.

  Similar tests were performed on the shapes of the long hollow ceramic members 2 and 3 in the examples shown in FIGS. 3 and 5, and similar results were obtained.

  From this result, the long hollow ceramic member of the present invention is formed in a polygonal shape in which the outer shape of the hollow portion 11 has sides parallel to the outer periphery, and grooves 12 are provided in the outer corners of the hollow portion 11. It was found that cracking can be suppressed near the center of the outer peripheral corner.

(Example 3)
Next, a molded body as a sample was prepared using the clay prepared in Example 1, and the depth and width of the groove of the long hollow ceramic member of the present invention were near the center of the outer peripheral corner. A test was conducted to confirm whether or not it would affect the cracks that occur in the film.

Using the clay prepared in Example 1, the shape of the long hollow ceramic member 1 of the example shown in FIG. 1 has an external dimension of a length L of 1 m, a width of 65 mm, a height of 65 mm, and a thickness t In the cross section, the hollow portion 11 is formed in a polygonal shape having sides parallel to the outer periphery so that the molded body No. 3 is provided with a groove 12 having a depth D ₁ and a width W ₁ shown in Table 1 at the same position as in FIG. 20 pieces of 7 to 31 were produced by extrusion molding. In addition, a molded body No. 1 which is a conventional long hollow ceramic member having the same outer dimensions and no groove 12 is used. Twenty-two 32 were produced. And the produced molded object No. 7-32 was gradually heated from 20 ° C. to near 80 ° C. and dried, and the number of good products was confirmed. Similar tests were also performed on the shapes of the long hollow ceramic members 2 and 3 in the examples shown in FIGS. The results are shown in Table 1. In Table 1, Dt is the distance between the edge of the outer corner of the hollow portion 11 provided with the groove 12 in the cross section and the outer peripheral side, and Wt is the distance of the hollow portion 11 provided with the groove 12 in the cross section. The distance between the other side of the outer corner and the outer side is shown.

As can be seen from the results shown in Table 1, in any case of the shape of the long hollow ceramic members 1 to 3 in the examples shown in FIGS. Nos. 7 to 31 are molded bodies having no grooves 12. There were more non-defective items than 32.

In any case of the shape of the long hollow ceramic members 1 to 3 in the examples shown in FIGS. 13～15,18～20 and 23-25, such as the depth D ₁ of the groove 12, the distance between the outer corners of the side and the outer peripheral side of the hollow portion 11 of the groove 12 in the cross-section is provided is 1/4 to 1/2 of dt, the distance between the width W ₁ of the groove 12, the other side and the outer peripheral side of the outer corner portion of the hollow portion 11 a groove 12 is provided in the cross section Wt Of the 20 molded bodies that were produced, 80% or more of the molded bodies were good products. In the molded body provided with the grooves 12 having the depth D ₁ and the width W ₁ outside this range, none of the 20 molded bodies having a good product number was more than 80%.

As a result, among the long hollow ceramic members of the present invention, in the long hollow ceramic member in which the outer shape of the hollow portion 11 is formed in a polygonal shape having sides parallel to the outer periphery in the cross section, the depth of the groove 12 D ₁ is, is 1/4 to 1/2 of the distance between the outer corners of the side and the outer peripheral side of the hollow portion 11 a groove 12 is provided in the cross section, the width W ₁ of the groove 12, It turned out that it is suitable that it is 1/4 or more and 1/2 or less of the distance between the other side of the outer corner of the hollow part 11 provided with the groove 12 in the cross section and the outer side.

Example 4
Next, a molded body as a sample was prepared using the clay prepared in Example 1, and the depth and width of the groove of the long hollow ceramic member of the present invention were near the center of the outer peripheral corner. A test was conducted to confirm whether or not it would affect the cracks that occur in the film.

Using the clay prepared in Example 1, the shape of the long hollow ceramic member 4 of the example shown in FIG. 7 is such that the outer dimensions are a length L of 1 m, a width of 65 mm, a height of 65 mm, and a thickness t. In the cross section, the shortest distance X between the outer shape of the hollow portion 11 and the apex O of the outer peripheral corner in the cross section is 20 mm, and the groove 12 is formed in the portion of the shortest distance X with the apex O of the outer peripheral corner of the outer shape of the hollow portion 11. In the molded body of the example to be a long hollow ceramic member provided with a groove 12 having a depth D ₁ and a width W ₁ shown in Table 2 provided in the outer corner of the hollow portion 11. Twenty-five each of 33-57 were produced by extrusion molding. In addition, a molded body No. 1 which is a conventional long hollow ceramic member having the same outer dimensions and no groove 12 is used. Twenty-five 58 pieces were produced. And the produced molded object No. The temperature of 33 to 58 was gradually raised from 20 ° C. to about 80 ° C. and dried, the number of good products was confirmed, and the results are shown in Table 2. X in Table 2 indicates the shortest distance between the outer shape of the hollow portion 11 and the vertex O of the outer peripheral corner in the cross section.

  As can be seen from the results shown in Table 2, compact No. Nos. 33 to 57 are molded bodies No. Compared with 58, the number of good products was large.

In addition, the molded product No. 39-41, no. 44-46 and no. 49-51, such as the depth D ₁ of the groove 12, is 1/4 to 1/2 of the shortest distance X between the apex O of the outer and the outer corner portion of the hollow portion 11 in the cross section, the grooves 12 In a molded product having a width W ₁ of ¼ or more and ½ or less of the shortest distance X between the outer shape of the hollow portion 11 and the apex O of the outer peripheral corner in the cross section, 80% or more of the produced 20 molded products. The molded product was a good product. In the molded body provided with the grooves 12 having the depth D ₁ and the width W ₁ outside this range, none of the 20 molded bodies having a good product number was more than 80%.

As a result, a long hollow ceramic member of the present invention, the depth D ₁ of the groove 12, more than 1/4 of the shortest distance X between the apex O of the outer and the outer corner portion of the hollow portion 11 in the cross section 1/2 It is found that the width W _{1 of the} groove 12 is preferably ¼ or more and ½ or less of the shortest distance X between the outer shape of the hollow portion 11 and the vertex O of the outer peripheral corner in the cross section. It was.

(Example 5)
Next, a sample in which the surface roughness (arithmetic average roughness Ra) of the inner surface of the groove of the long hollow ceramic member of the present invention was changed was manufactured, and a test for confirming the effect was performed.

  In the example of the long hollow ceramic member 1 shown in FIG. 15, the surface roughness (arithmetic mean roughness Ra, hereinafter also referred to as surface roughness Ra) of the inner peripheral surface of the sintered body is 3 μm, and the surface roughness Ra of the inner surface of the groove 12 is the value shown in Table 2. The molded body No. changed to be 20 pieces of 59-69 were produced respectively. In addition, compact No. The surface roughness Ra of 59 to 69 was changed by adjusting the surface roughness of the portions corresponding to the inner peripheral surface of the molded body of the extrusion die portion 87 of the extruder 80 and the inner surface of the groove 12, respectively. And similarly to the test of Example 2, the molded body No. with adjusted surface roughness Ra. 59-69 was gradually heated from 20 ° C. to near 80 ° C. and dried, and the number of good products was confirmed. The same test is also performed on the shape of the long hollow ceramic members 2 and 3 of the example shown in FIGS. 3 and 5, and the long hollow ceramic of the example shown in FIG. Formed body No. 4 in the shape of member 4. A similar test was conducted at 41. The results are shown in Table 3.

  As can be seen from the results shown in Table 3, the surface roughness Ra of the inner surface of the groove 12 is the inner in any case of the shape of the long hollow ceramic members 1 to 4 in the examples shown in FIGS. If it was larger than the surface roughness Ra of the peripheral surface, the number of non-defective products was larger.

  As a result, it was found that in the long hollow ceramic member of the present invention, when the surface roughness Ra of the inner surface of the groove 12 is larger than the surface roughness Ra of the inner peripheral surface, the occurrence of cracks can be further suppressed.

(Example 6)
Next, a molded body to be a sample is prepared using the clay prepared in Example 1, and in the long hollow ceramic member of the present invention, the presence or absence of the second groove is a crack that occurs near the center of the outer peripheral corner. The ratio of the total value of the width of the second groove to the depth and width of the second groove and the length of the side between adjacent outer peripheral corners is determined. Then, a test was conducted to confirm whether or not it affects cracks generated near the center of the outer peripheral corner.

Using the clay prepared in Example 1, the shape of the long hollow ceramic member 5 of the example shown in FIG. 10 has an external dimension of a length L of 1 m, a width of 65 mm, a height of 65 mm, and a thickness t Is formed in a polygonal shape having an outer shape parallel to the outer periphery so that the outer diameter of the hollow portion 11 is 10 mm. A groove 12 (depth D ₁ : 2 mm, width W ₁ : 2 mm) having the same size as 7 is provided at the outer corner, and the depth shown in Table 4 showing the depth and width of the second groove 14. As shown in Table 5, the ratio of the total value of the width W ₂ to the length W ₃ of the side between the adjacent outer peripheral corners (hereinafter, the second groove 14 having the width D ₂ and the width W ₂ ) , Simply referred to as the ratio occupied by the total value of the width W ₂ ) is 20%, 30%, 40%, 50%, and 60%. 20 to 70 were produced by extrusion molding, and the formed compact No. 70-94 was gradually heated from 20 ° C. to near 80 ° C. and dried, and the number of good products was confirmed as a good product having no cracks in the vicinity of the center of the outer peripheral corner. The results are shown in Table 5.

In addition, all the 2nd groove | channels 14 of the molded objects 70-94 arrange | position the distance between the adjacent 2nd groove | channels 14 at equal intervals, and the groove | channel 12 and the 2nd groove | channel 14 adjacent to the groove | channel 12 are the same. The distance between them was 3 mm. Also, if the unified all width W ₂ of the second groove 14 is impossible to proportion the total value of the width W ₂ shown in Table 4, for adjustment of the total value of the width W ₂ One second groove 14 is provided at the center between the outer peripheral corners. The reason why the _second groove 14 for adjusting the total value of the width W2 is provided in the center between the outer peripheral corners is that the width around the second groove 14 may be different because of the different width of the adjacent grooves. This is because the influence due to the degree of is smaller.

A similar test was also performed on the shapes of the long hollow ceramic members 6 to 8 in the examples shown in FIGS. The results are shown in Table 5. Note that, in the example of the long hollow ceramic member 8 shown in FIG. Nos. 70 to 94 have an outer dimension of a length L of 1 m, a width of 65 mm, a height of 65 mm, and a thickness t of 10 mm, and the shortest distance X between the outer shape of the hollow portion 11 and the vertex O of the outer peripheral corner in the cross section. 20 mm, and the molded product No. A groove 12 having the same size as that of the groove 34 (depth D ₁ : 4 mm, width W ₁ : 5 mm) has a molded body No. It is located at the same position as 34. The length W ₃ of the edge between the outer peripheral corner portions adjacent in the outer shape of the hollow portion 11 in the cross section, the point of the shortest and the apex O of the outer peripheral corner portion, the other vertex of the outer peripheral corner portion adjacent The shortest distance along the outer shape of the hollow portion 11 between the shortest point and O.

As can be seen from the results shown in Table 5, compacts Nos. 5 to 7 in the shape of the long hollow ceramic members 5 to 7 in the examples shown in FIGS. Nos. 70 to 94 are molded Nos. No. 2 in the shape of the long hollow ceramic members 1 to 3 of the example shown in FIGS. Compared to 7, there were more non-defective products. Further, in the example of the long hollow ceramic member 8 shown in FIG. Nos. 70 to 94 are molded Nos. No. 2 of the shape of the long hollow ceramic member 4 in the example shown in FIG. There were more non-defective products than 34.

Moreover, in any case of the shape of the long hollow ceramic members 5 to 8 in the examples shown in FIGS. 76-78, no. 81-83 and no. The depth of the second groove 14 such as 86 to 88 is not less than 1/10 and not more than 1/4 of the thickness between the outer shape and the outer periphery of the hollow portion 11, and the width W2 of the _second groove 14 is The thickness of the plurality of second grooves 14 provided between adjacent outer peripheral corners of the cross section of the outer shape of the hollow portion 11 is not less than 1/10 and not more than 1/4 of the thickness between the outer shape and the outer periphery of the hollow portion. in 30% to 50% of the molded body side length of between circumference edge of the total width W ₂ are adjacent, cracks were found to be less likely to especially near the center of the outer peripheral corner portion of the molded body.

As a result, among the long hollow ceramic member of the present invention, a plurality of second grooves 14 extending in the longitudinal direction are provided between the grooves 12 in the vicinity of the adjacent outer peripheral corners of the outer cross section of the hollow portion 11. It was found that cracks can be further suppressed from occurring near the center of the outer peripheral corners. The depth of the second groove 14 is not less than 1/10 and not more than 1/4 of the thickness between the outer shape and the outer periphery of the hollow portion 11, and the width W ₂ of the second groove 14 is the outer shape of the hollow portion 11. The width W ₂ of the plurality of second grooves 14 provided between adjacent outer peripheral corners of the cross section of the outer shape of the hollow portion 11 is 1/10 or more and ¼ or less of the thickness between the outer periphery and the outer periphery. It has been found that the sum is preferably 30% to 50% of the length of the side between the adjacent corners.

1-8: Long hollow ceramic member
11: Hollow part
12: Groove
61: Reinforcement
62: Polygonal outer shape including all the hollow portions 11 and having a minimum area D ₁ : Depth of the groove 12 W ₁ : Width of the groove 12 D ₂ : Depth of the second groove 14 W ₂ : Width of second groove 14 W ₃ : Length of side between adjacent outer peripheral corners L: Length of long hollow ceramic member t: Wall thickness O: Apex of outer peripheral corner portion X: Outline of hollow portion The shortest distance from the apex of the outer corner

Claims (8)

It is a long hollow ceramic member having a hollow portion penetrating in the longitudinal direction, the outer periphery of the cross section perpendicular to the longitudinal direction is polygonal, and in the vicinity of the outer peripheral corner of the cross section of the outer shape of the hollow portion, long hollow ceramic member, characterized in Rukoto such by calcining after drying the molded body having a groove extending in the direction.   The said hollow part in the said cross section is formed in the polygonal shape which an external shape has a side parallel to the said outer periphery, The said groove | channel is provided in the external corner | angular part of the said hollow part. The long hollow ceramic member described.   The depth of the groove is ¼ or more and ½ or less of the distance between the side of the outer corner of the hollow portion where the groove is provided in the cross section and the side of the outer periphery, A width is ¼ or more and ½ or less of a distance between the other side of the outer shape of the outer corner portion of the hollow portion where the groove is provided in the cross section and the outer peripheral side. The long hollow ceramic member according to claim 2.   In the cross section, the hollow portion has a circular outer shape, and the groove is provided in a portion at a shortest distance from a vertex of the outer peripheral corner portion of the outer shape of the hollow portion. Item 5. The long hollow ceramic member according to Item 1.   The depth of the groove is ¼ or more and ½ or less of the shortest distance between the outer shape of the hollow portion and the apex of the outer peripheral corner portion, and the width of the groove is equal to the outer shape of the hollow portion and the outer peripheral angle. The long hollow ceramic member according to claim 4, which is ¼ or more and ½ or less of the shortest distance from the top of the portion.   6. The long hollow ceramic member according to claim 1, wherein an arithmetic average roughness Ra of an inner surface of the groove is larger than an arithmetic average roughness Ra of an inner peripheral surface of the hollow portion.   The plurality of second grooves extending in the longitudinal direction are provided between the grooves in the vicinity of the outer peripheral corners adjacent to each other in the cross section of the outer shape of the hollow part. The long hollow ceramic member according to claim 1. The depth of the second groove is 1/10 to 1/4 of the thickness between the outer shape of the hollow portion and the outer periphery, and the width of the second groove is the outer shape of the hollow portion and the outer periphery. 1/10 or more and 1/4 or less of the thickness between the two and the total width of the plurality of second grooves provided between the adjacent outer peripheral corners of the cross section of the outer shape of the hollow portion is adjacent The long hollow ceramic member according to claim 7, wherein the length is 30% to 50% of the side length between the matching outer peripheral corners.

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