JP2018158551A - Extrusion molding device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an extrusion molding device having a gear pump provided with oblique tooth gears and capable of the stable feeding of a molding material to a nozzle part.SOLUTION: Provided is an extrusion molding device 1 mainly comprising: a barrel 10; an extrusion screw 20; a nozzle part 30 for forming a honeycomb molded body in which the average molded body temperature is regulated to 32°C or higher; and a gear pump 40. The gear pump 40 includes: a pair of oblique tooth gears 42a, 42b having a plurality of oblique teeth; and a gear enclosure part 46 having a gear space part 43 capable of including the pair of oblique tooth gears 42a, 42b and capable of storing them, an introduction space part 44 for introducing a molding material 2 into the gear space part 43, and a feed space part 45 for feeding the molding material 2 from the gear space part 43 to the nozzle part 30. The feed space part 45 is extended from the outlet port of the gear space part 43 and has a cylindrical tube part 50 with a tube diameter of 24 mm or lower.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an extrusion molding apparatus. More specifically, the present invention relates to an extrusion molding apparatus that is used in an extrusion process for extruding a ceramic honeycomb molded body and has a gear pump for supplying a molding material (kneaded material) to a die.

  Conventionally, ceramic honeycomb structures have been used in a wide variety of applications such as automobile exhaust gas purification catalyst carriers, diesel particulate removal filters, gasoline particulate removal filters, and combustion apparatus heat storage bodies. Here, a ceramic honeycomb structure (hereinafter simply referred to as “honeycomb structure”) is formed by extruding a honeycomb formed body (or extrusion die) from a die (or an extrusion die) using an extrusion molding apparatus, It is manufactured by firing a honeycomb formed body at a high temperature using a firing furnace (firing step). As a result, a honeycomb structure including a porous partition wall defining a plurality of cells extending from one end face forming the fluid flow path to the other end face is obtained.

  In the extrusion molding process, for example, an extrusion molding apparatus schematically shown in FIG. 6 is generally used (see Patent Document 1). The extrusion molding apparatus 100 includes a pair of extrusion screws 101 arranged in parallel to each other, a barrel 103 having a space in which the extrusion screw 101 can be accommodated, an opening 102 on one end side, It is configured as a so-called “biaxial extruder” having an extrusion molding base 104 connected to the opening 102. In addition to such a twin screw extruder, a “single screw extruder” having only one extrusion screw may be used.

  A honeycomb formed body 112 is formed using the extrusion molding apparatus 100 having the above configuration. First, the molding material 107 is charged into the conveyance space 106 inside the barrel 103 from the material charging unit 105 connected to the upstream side of the barrel 103. Then, the charged molding material 107 is kneaded while being given a shearing force by the rotation of a pair of extrusion screws 101 respectively connected to the driving device 108, and in the conveying direction A that coincides with the horizontal direction up to the opening 102 side. Conveyed along. Thereafter, the molding material 107 is continuously supplied from the opening 102 toward the base 104.

  Here, the base portion 104 has a substantially casing shape, and a base space 113 through which the molding material 107 circulates is provided, and impurities in the molding material 107 are removed so as to partition the base space 113. A filtration net 109 (screen) is installed. Thereby, the base space 113 is partitioned into a first space 110 a located upstream in the conveying direction A of the molding material 107 and a second space 110 b located downstream.

  Then, when the first space 110a is filled with the molding material 107 supplied from the opening 102, the molding material 107 is supplied to the second space 110b through the filter 109, and finally a plurality of slits (not shown). The molding material 107 passes through the base 111 provided with. Thereby, the honeycomb formed body 112 having the lattice-shaped partition walls matching the slit shape is extruded.

  Here, the extrusion speed, the extrusion amount, or the extrusion pressure of the molding material 107 to be extruded from the base part 104 is controlled by the driving device 108, and mainly depends on the rotation speed, the rotation amount, etc. of the pair of extrusion screws 101 that are rotationally driven. Adjusted. That is, the molding material 107 can be stably supplied to the base 111 (base part 104) by stabilizing the rotational speed of the extrusion screw 101 and the like.

  On the other hand, in addition to the extrusion molding apparatus 100 having the above-described configuration, for example, an apparatus that performs extrusion molding of a molding material that has been passed through a first twin-screw extruder through a second twin-screw extruder (pumping extruder) has been proposed. (See Patent Document 2).

  Furthermore, an extrusion molding process is disclosed in which at least one gear pump is arranged between the twin-screw extruder and the die part to extrude the powdered material (see Patent Document 3). According to this, after pre-processing such as kneading of molding material with a twin screw extruder, the molding material is fed to the gear pump through the single screw extruder, and then the extrusion speed, extrusion pressure, extrusion amount, etc. are adjusted by the gear pump. In this state, the molding material can be supplied to the base part.

JP 2008-114414 A Japanese translation of PCT publication No. 2003-527981 U.S. Pat. No. 5,213,737

  However, the extrusion molding apparatus as described above sometimes has the following problems. That is, in the case of an extrusion molding apparatus such as a twin-screw extruder or a single-screw extruder, the outer and inner portions of the extrusion screw or the extrusion screw is rotated by the rotation of screw blades formed spirally along the screw axis. There may be a deviation in the extrusion speed of the molding material between the left and right. This phenomenon has been difficult to completely eliminate due to the characteristics of the extrusion screw.

  For this reason, the roundness of the honeycomb molded body may be impaired, for example, a problem such as bending of the extruded honeycomb molded body or an elliptical cross section of the honeycomb molded body. As a result, a large number of honeycomb molded bodies deviating from the shape of the molded body, which is a design standard, may be formed.

  Therefore, attempts have been made to solve the above problems. For example, a technique for conveying a molding material composed of a ceramic raw material using a gear pump (particularly, an external gear pump) generally used when mainly conveying a fluid has been proposed.

  Here, a spur gear-shaped gear (spur gear, spur gear) is often used for a general gear pump. By the meshing of the pair of spur gears, the molding material can be conveyed from one to the other.

  However, in the case of a gear pump using a spur gear, a so-called “pulsation” in which the extrusion speed and the extrusion amount of the molding material change periodically may occur. As a result, the shape of the honeycomb molded body in the axial direction (conveying direction or extrusion direction) changes due to periodic changes such as the extrusion speed of the molding material due to the above “pulsation”, etc. There was a problem. For this reason, it has been difficult to use a gear pump using a spur gear.

  Therefore, in order to eliminate the above-described problems, a gear pump that employs an inclined gear having a plurality of inclined teeth (helical teeth) is used instead of the spur gear. Thereby, the fluctuation | variation of the above periodic extrusion speeds, etc. can be eliminated. On the other hand, the inclined gear is formed such that the inclined tooth portion is inclined in an oblique direction with respect to the gear shaft (rotating shaft) of the inclined gear. Therefore, the right and left extrusion speeds may be biased with respect to the extrusion direction of the molding material (direction perpendicular to the gear axis). Furthermore, depending on the extrusion amount and extrusion speed of the molding material passing through the die part, there may be a difference between the left and right.

  As a result, the temperature distribution in the cross section of the honeycomb formed body may differ greatly due to the generation of frictional force depending on the extrusion speed and the extrusion amount. More specifically, a region where the extrusion speed is high and the amount of extrusion is large exhibits a relatively high temperature distribution, while a region where the extrusion speed is slow and the amount of extrusion is small exhibits a relatively low temperature distribution. There was to show. As a result, problems such as bending to the left or right with respect to the honeycomb formed body (extrusion direction) may occur. Details of the mechanism will be described later.

  Therefore, in view of the above circumstances, the present invention has an object to provide an extrusion molding apparatus that has a gear pump including a bevel gear and that can stably supply a molding material to a die portion.

  According to the present invention, the following extrusion molding apparatus is provided.

[1] A conveyance space for conveying a ceramic molding material in a horizontal direction while kneading, a barrel provided with an opening at one end, and a conveyance direction of the molding material accommodated in the conveyance space of the barrel. The screw shaft is made to coincide with each other, the extrusion screw rotatably supported in the conveying space, and the opening of the barrel are provided so as to extrude the molding material, and the average molded body temperature is 32 ° C. A die part that forms the honeycomb formed body adjusted as described above, and the molding material that is interposed between the opening part and the die part of the barrel and conveyed to the opening part is supplied toward the die part. The gear pump includes a pair of inclined gears having a plurality of inclined teeth, a pair of the inclined gears, a gear space that can be accommodated, and the opening of the barrel. Communicating between the inlets of the space part, leading the molding material to the gear space part, communicating between the outlet part of the gear space part and the base part, An extrusion molding apparatus having a cylindrical cylindrical tube portion that extends from the outlet port and has a tube diameter of 24 mm or less.

[2] The extrusion apparatus according to [1], wherein a tube length of the cylindrical tube portion from the outlet port to a tube end portion of the cylindrical tube portion is in a range of 20 to 80 mm.

[3] The extrusion apparatus according to [1] or [2], including a pair of the extrusion screws that are accommodated in the conveyance space of the barrel and are arranged in parallel with the screw shafts being parallel to each other. .

  According to the extrusion molding apparatus of the present invention, a gear pump is interposed between the barrel and the base part, and the extrusion speed of the molding material and the stable supply of the extrusion speed are achieved by the gear pump arranged on the upstream side of the base part. Can do. In particular, it is possible to eliminate the bias such as the extrusion speed peculiar to the pair of inclined gears.

  In particular, a cylindrical pipe part having a relatively simple structure or structure provided in the supply space inside the gear pump is provided to adjust the pipe diameter and pipe length, and to set the average molded body temperature of the honeycomb molded body. In this way, the above problems can be solved and the shape of the formed body of the honeycomb formed body can be stabilized. Thereby, the product shape of the honeycomb structure obtained as a final product becomes favorable.

It is explanatory drawing which shows typically schematic structure of the extrusion molding apparatus of one Embodiment of this invention. It is a perspective view showing typically a pair of inclined gears and the arrangement state. It is a schematic cross section which shows schematic structure of the periphery of a gear pump and a nozzle | cap | die part. It is explanatory drawing which summarized the influence of the temperature distribution of the molded object cross section of a honeycomb molded object by the change of the pipe diameter and pipe length of a cylindrical pipe part. It is explanatory drawing which summarized the influence of the molded object shape by the change of the molded object temperature of a honeycomb molded object. It is explanatory drawing which shows typically schematic structure of the conventional extrusion molding apparatus. It is a schematic cross section which shows schematic structure of the periphery of a gear pump and a nozzle | cap | die part in the extrusion molding apparatus which does not have a cylindrical pipe part.

  Hereinafter, embodiments of the extrusion molding apparatus of the present invention will be described in detail with reference to the drawings. The extrusion molding apparatus of the present invention is not limited to the following embodiments, and various design changes, modifications, improvements and the like can be added without departing from the scope of the present invention. .

  As shown in FIGS. 1 to 5, an extrusion molding apparatus 1 according to an embodiment of the present invention includes a plurality of cells serving as fluid flow paths extending from one end face to the other end face from a ceramic molding material 2. This is a device for extruding the honeycomb formed body 3 having partition walls to form a partition, and is an apparatus used particularly in an extrusion forming process in a method for manufacturing a honeycomb structure (not shown).

  The extrusion molding apparatus 1 mainly includes a barrel 10, an extrusion screw 20, a base part 30, and a gear pump 40 as a basic configuration. Furthermore, a drive device 60 for controlling the rotational drive of the extrusion screw 20 and a material charging unit 70 for charging the molding material 2 into the barrel 10 are provided (see FIG. 1). In the extrusion molding apparatus 1 of the present embodiment, the material feeding unit 70 is installed near one end side of the barrel 10 (corresponding to the left side of the paper in FIG. 1), and the molding material 2 is fed from above the barrel 10 (FIG. 1). Further, the conveying direction A of the molding material 2 in the barrel 10 (from the left direction to the right direction in FIG. 1) is made to coincide with the horizontal direction and conveyed and kneaded.

  Next, the detail is demonstrated about each structure of the extrusion molding apparatus 1 of this embodiment. The barrel 10 is provided with an opening 11 at one end, and further has a substantially drum-like structure including a transport space 12 for transporting the molding material 2 along the transport direction A while kneading.

  On the other hand, the extrusion screw 20 mainly includes a substantially rod-shaped screw shaft 21 and screw blades 22 wound in a spiral shape (screw shape) along the shaft surface of the screw shaft 21. In the extrusion molding apparatus 1 of the present embodiment, a pair of the extrusion screws 20 having the above-described configuration is provided, and the screw shafts 21 are arranged in parallel so as to be parallel to each other and are accommodated in the conveyance space 12 of the barrel 10. . The shaft is rotatably supported with the screw shaft 21 as an axis while being accommodated in the transfer space 12.

  That is, the extrusion molding apparatus 1 of the present embodiment is configured as a so-called “biaxial extruder” by the configuration of the barrel 10 and the pair of extrusion screws 20. FIG. 1 schematically shows the extrusion molding apparatus 1 according to the present embodiment, and only a part of the pair of extrusion screws 20 (the extrusion screw 20 on the front side of the paper) is illustrated. Further, as a general term for the configuration of the barrel 10 and the extrusion screw 20, it may be hereinafter referred to as a “molding part”.

  In addition, the barrel 10 has a structure in which a part of two circles having the same diameter are coupled to each other in a cross-sectional view orthogonal to the transport direction in the inner peripheral shape of the transport space 12. (Circle) is formed so as to coincide with the axis of each screw shaft 21 of the pair of extrusion screws 20. The inner diameter of each circle constituting the conveying space 12 of the barrel 10 is formed to be slightly larger than the diameter of the screw blade 22 of the extrusion screw 20. Thereby, rotation of the extrusion screw 20 is not inhibited. Moreover, when the pair of extrusion screws 20 arranged side by side rotate, they are installed so that the screw blades 22 do not contact each other.

  By providing the configuration of the barrel 10 and the pair of extrusion screws 20, the molding material 2 introduced into the conveyance space 12 in the barrel 10 from the material introduction unit 70 is formed into a helical screw blade 22 accompanying the rotation of the extrusion screw 20. Is conveyed along the horizontal direction (conveyance direction A) by the spiral propulsion force. Here, although the extrusion screw 20 is not specifically limited, a conventionally well-known thing can be used.

  For example, a so-called “single screw” or “double screw” in which the winding state of the screw blade 22 with respect to the screw shaft 21 is changed can be used. Here, in the case of a single screw, when the extrusion screw 20 rotates once, the distance (conveyance distance (lead)) of the molding material 2 corresponding to the helical propulsive force acting in the conveyance direction is the interval between the screw blades 22 ( Pitch). On the other hand, in the case of a double screw, the conveyance distance corresponds to two pitches. In addition, you may use the extrusion screw of various shapes.

  Furthermore, as described above, the extrusion molding apparatus 1 according to the present embodiment is interposed between the base part 30 provided at a position facing the molding part (the opening part 11 of the barrel 10), and the molding part and the base part 30. And a gear pump 40 that supplies the molding material 2 toward the base part 30.

  Here, the base portion 30 has a substantially casing shape, and is provided with a base space 31 through which the molding material 2 supplied from the gear pump 40 passes, so that the base space 31 is partitioned substantially in the vicinity of the center. A filter screen 32 (screen) for removing impurities in the molding material 2 is provided. As a result, the die space 31 is partitioned into a first space 33 a located on the upstream side in the conveying direction A of the molding material 2 and a second space 33 b located on the downstream side.

  Then, when the first space 33a is filled with the molding material 2 supplied from the gear pump 40, which will be described later, the molding material 2 is supplied to the second space 33b through the filtration net 32, and finally a plurality of slits (not shown). The molding material 2 passes through the base 34 provided with a). Thereby, the honeycomb formed body 3 having the lattice-shaped partition walls matching the slit shape is extruded.

  Here, the first space 33 a is configured as a frustoconical space that gradually expands from the upstream side toward the filtration net 32. On the other hand, the second space 33 b is configured as a substantially cylindrical space after having passed through the filter screen 32 and slightly reduced in diameter to approximately the same size as the base 34. The internal configuration of the base part 30 is not particularly limited. In addition, you may attach as needed various structures, such as a baffle plate for adjusting the flow of the molding material 2 which passes the nozzle | cap | die part 30. As shown in FIG.

  Furthermore, in the extrusion molding apparatus 1 of this embodiment, the average molded body temperature of the honeycomb molded body extruded from the die part 30 is adjusted to be 32 ° C. or higher. Here, the average of the molded body temperature represents an average value of the temperature of the honeycomb molded body 3 immediately after extrusion molding, which is measured using a known temperature measuring device (thermography or the like). In addition, in order to set the average molded body temperature of the honeycomb molded body 3 to 32 ° C. or more, the output of the cooling device that cools the molding material passing through the molding section, the gear pump 40, and the base section 30 can be adjusted. Done. The fluidity of the molding material can be improved by adjusting the temperature of the molding material.

  On the other hand, the gear pump 40 connected to the base part 30 includes a pair of inclined gears 42a and 42b having a plurality of inclined teeth 41 and a pair of inclined gears 42a and 42b, as shown in FIGS. The space 10 that can be accommodated, the introduction space 44 that connects the barrel 10 and the introduction port 43a of the gear space 43, and the outlet 43b and the base 30 of the gear space 43. And a gear housing portion 46 having inside each space of a supply space portion 45 that connects between them.

  Here, for example, as shown in FIG. 2, the inclined gears 42 a and 42 b include a gear base 47 having a substantially cylindrical structure, and a plurality of inclined teeth 41 projecting outward from the gear base 47. It has been done. Furthermore, the inclined teeth 41 are provided obliquely with respect to the gear shaft B of the gear base 47 (see the broken line in FIG. 2).

  The gear space 43 is housed in a state where the gear shafts B of the pair of inclined gears 42a and 42b are aligned in the vertical direction and the inclined teeth 41 are combined so that they can be engaged with each other. By adopting such a configuration, it cooperates with the rotation of one inclined gear 42a (or the other inclined gear 42b), the inclined teeth 41 mesh with each other, and the other inclined gear 42b (or one inclined tooth). The gear 42a) can be rotated.

  In addition, the gear pump 40 in the extrusion molding apparatus 1 of this embodiment is connected to the gear shaft B of one and / or the other inclined gears 42a and 42b, and a driving force generated by a gear driving device (not shown) for the gear pump. A drive transmission mechanism for driving (rotational force) the pair of inclined gears 42a and 42b via the gear shaft B is provided. As a result, the pair of inclined gears 42 a and 42 b can rotate while being accommodated in the gear space 43 of the gear housing 46.

  At this time, as shown in FIG. 2, when the conveying direction of the molding material 2 is changed from the diagonally upper left direction to the diagonally lower right direction and the gear pump 40 and the inclined gears 42a and 42b are viewed from the diagonally lower left side of the plane, The tooth gear 42a rotates in the clockwise rotation direction C1, and the lower oblique gear 42b rotates in the counterclockwise rotation direction C2. As a result, the molding material 2 is filled into a plurality of conveying spaces 48 (see hatched portions in FIG. 2) surrounded by the gap between the inclined teeth 41 of the inclined gears 42 a and 42 b and the inner peripheral surface of the gear space 43. The molding material 2 is conveyed along the rotation directions C1 and C2.

  Here, the gear space portion 43 is configured as a space for housing (storing) a pair of inclined gears 42 a and 42 b arranged with the position of the gear shaft B aligned vertically in the gear housing portion 46. A pair of cylindrical gear spaces 49a and 49b that are slightly larger than the inclined gears 42a and 42b are combined. Here, the cylindrical gear spaces 49a and 49b are configured in a state in which a part of each other overlaps, and the introduction port 43a and the outlet port 43b described above are formed on the upstream side and the downstream side of the overlapping part, respectively. Yes.

  The gear housing 46 further communicates from the opening 11 of the barrel 10 to the introduction port 43a of the gear space 43, and an introduction space 44 as a space for introducing the molding material 2 to the gear space 43, It is formed at a position sandwiching the introduction space portion 44 and the gear space portion 43, and includes a supply space portion 45 for communicating the base portion 30 from the outlet 43 b and supplying the molding material 2 to the base portion 30. . That is, a space is formed inside the gear housing 46 in the order of the introduction space 44, the gear space 43, and the supply space 45 from the upstream side where the molding material 2 is conveyed. The introduction space 44 has a frustoconical shape that gradually decreases in diameter from the opening diameter of the opening 11 of the barrel 10 to the opening diameter of the introduction port 43a.

  On the other hand, as shown in FIGS. 1 and 3, the supply space 45 has a substantially cylindrical shape extending from the outlet 43 b of the gear space 43 to a predetermined length (tube length L) with a constant tube diameter D. The cylindrical tube portion 50 is provided.

  As a result, the molding material 2 that has passed through the pair of inclined gears 42 a and 42 b and the gear space 43 passes through the supply space 45 provided on the downstream side of the gear space 43. At this time, the molding material 2 advances through the cylindrical tube portion 50 held at a constant tube diameter D for a predetermined distance (tube length L) immediately after being derived from the gear space portion 43. That is, while passing through the cylindrical tube portion 50, it is in a state where it is restricted to advance while expanding in the vertical direction and the horizontal direction with respect to the conveyance direction A.

  As a result, even if there is a deviation in the left-right difference between the extrusion speed and the amount of extrusion immediately after passing through the pair of inclined gears 42a, 42b, while traveling through the cylindrical tube portion 50 having a relatively small tube diameter D, The left / right difference is eliminated. Thereby, the malfunction which arises in the molded object shape of the honeycomb molded object 3 in the case of extrusion molding is suppressed.

  In particular, in the extrusion molding apparatus 1 of the present embodiment, the tube diameter D of the cylindrical tube portion 50 formed to be the same as the opening diameter of the outlet port 43b is limited to 24 mm or less. By making the tube diameter D 24 mm or less, the effect of eliminating the left-right difference can be enhanced. In addition, when the pipe diameter D is larger than 24 mm, the molding material 2 advances while expanding in the vertical direction and the horizontal direction, so that it is not possible to obtain a sufficient effect of eliminating the horizontal difference.

  In addition, the length (tube length L) from the outlet port 43b of the gear space portion 43 to the tube end portion (not shown) of the cylindrical tube portion 50 is set to a range of 20 to 80 mm. Is done. That is, in order to eliminate the above-described left / right difference, the length of the cylindrical tube portion 50 is required to some extent, and at least the tube length L is set to 20 mm or more. On the other hand, even if the tube length L exceeds 80 mm, there is almost no effect on the elimination of the subsequent left-right difference, and therefore no longer tube length L is required. Therefore, the tube length L is limited to the numerical range.

  In addition, in the supply space part 45, the shape from the pipe | tube end part of the said cylindrical pipe part 50 is not specifically limited. Therefore, as shown in FIG. 1 and FIG. 3, etc., after slightly expanding from the tube diameter D of the cylindrical tube portion 50, a space (connection space portion) connected to the base portion 30 while gradually increasing the opening diameter thereafter. 51) or other shaped spaces may be used.

  As described above, according to the extrusion molding apparatus 1 of the present embodiment, the gear pump 40 composed of the inclined gears 42 a and 42 b is interposed between the molding part and the base part 30, and the gear housing part of the gear pump 40. The cylindrical pipe portion 50 provided inside 46 can effectively eliminate the left-right difference such as the extrusion speed peculiar to the inclined gears 42a and 42b. As a result, the extrusion screw 20 and the gear pump 40 can be used together, the molding material 2 can be stably supplied to the die part 30 (die 34), and the shape of the honeycomb molded body 3 can be maintained in a good state. can do.

  Furthermore, in order to explain the effect of the cylindrical tube portion 50 in the extrusion molding apparatus 1 of the present embodiment, the explanation will be made in comparison with the extrusion molding apparatus 200 (see FIG. 7) which is a comparison object of the present invention. Here, the extrusion molding apparatus 200 has substantially the same configuration as the above-described extrusion molding apparatus 1 of the present embodiment, and includes a molding unit (a barrel 10 and an extrusion screw (not shown)), a base unit 30 and the like. It has. About the structure which concerns, the same code | symbol is attached | subjected and detailed description is abbreviate | omitted.

  On the other hand, the extrusion molding apparatus 200 includes a gear pump 210 interposed between the molding part and the base part 30. The gear pump 210 also has the same configuration as that of the gear pump 40 described above, for example, the inclined gears 42a and 42b, and the detailed description thereof will be omitted.

  As shown in FIG. 7, the gear pump 210 of the extrusion molding apparatus 200 includes a base space 31 (first space 33 a) of the base portion 30 from the outlet 43 b of the gear space portion 43 in which the pair of inclined gears 42 a and 42 b are accommodated. The supply space portion 211 extending up to is formed by a truncated cone space portion 212 having a truncated cone shape that gradually increases in diameter from the opening diameter of the outlet port 43b. That is, it is a thing of the general structure which does not have the structure of the cylindrical pipe part 50 of the gear pump 40 in the extrusion molding apparatus 1 of this embodiment.

  Thereby, the molding material (not shown) that has passed through the outlet 43b spreads in the frustoconical space 212 while expanding in the vertical direction and the horizontal direction with respect to the conveyance direction (corresponding to the left direction to the right direction in FIG. 7). Will go on. That is, there is no restriction on the spread in the vertical direction. Therefore, the molding material is supplied to the die part 30 while maintaining the left-right difference such as the extrusion speed and the extrusion amount. Thereby, an effect like the extrusion molding apparatus 1 of this embodiment cannot be acquired.

  Hereinafter, although the extrusion molding apparatus of this invention is demonstrated based on the following Example, the extrusion molding apparatus of this invention is not limited to these Examples.

(1) Formation of honeycomb formed body (Examples 1 to 3, Comparative Examples 1 to 7)
Using the extrusion molding apparatus of the present invention schematically shown in the figure, a molding material prepared by blending various ceramic raw materials was extruded to form a cylindrical honeycomb molded body. Here, in Examples 1 to 3 and Comparative Example 1, extrusion was performed by using a gear pump and adjusting so that the average temperature of the formed body of the honeycomb formed body extruded from the die was 32 ° C. It is. In order to adjust the temperature of the formed body of the honeycomb formed body, the temperature of the molding material is adjusted in the forming portion, the gear pump, and the base portion. Here, Table 1 below shows a summary of the maximum and minimum values of various molding conditions related to the extrusion molding of the honeycomb molded body by the extrusion molding apparatus of the present invention.

  Here, the honeycomb formed bodies of Examples 1 to 3 were formed using a gear pump having a cylindrical pipe portion in which the tube diameter D and the tube length L were matched within the ranges defined in the present invention. Is. On the other hand, in Comparative Example 1, the value of the tube diameter D is deviated from the range defined in the present invention. Moreover, the comparative example 2 uses the conventional shaping | molding part which does not have a gear pump and performs extrusion molding only with an extrusion screw.

  Comparative Examples 4 to 7 are for studying the influence of the average formed body temperature of the honeycomb formed body, and the formed body temperature was 25 ° C. (Comparative Examples 3, 6, and 7) or 28 ° C. (Comparative Example 4). , 5). At this time, the tube diameter and the tube length of the cylindrical tube portion of the gear pump are within the range defined in the present invention. Except for Comparative Example 2 in which no gear pump was used, the molding material supply rate was set to 400 kg / h. On the other hand, in Comparative Example 2, the molding material supply rate was set to 200 kg / h.

  Extrusion conditions in Examples 1 to 3 and Comparative Examples 1 to 7, the temperature of the cross section of the formed body of the honeycomb formed body, the temperature distribution of the cross section of the formed body of the honeycomb formed body (Examples 1 to 3 and Comparative Example 1, 4 and 5 show a summary of the load of the gear pump (Examples 1 to 3 and Comparative Examples 1 and 2 only), the height difference between the left and right, and the amount of the molding material supplied.

(2) Temperature distribution of the cross section of the formed body The temperature distribution of the cross section of the formed body of the honeycomb formed body immediately after being extruded from the die was measured using a known temperature measuring device (thermography). According to this, as shown in FIG. 4, it was confirmed that the honeycomb formed bodies of Examples 1 to 3 had the highest center part of the cross section of the formed body and gradually decreased in the formed body temperature toward the outer periphery. . That is, it was shown that good extrusion molding was performed without unevenness in the extrusion speed and the extrusion amount.

  On the other hand, in the case of Comparative Example 1, it was confirmed that the temperature distribution of the cross section of the molded body was uneven. That is, it was shown that when the tube diameter D of the cylindrical tube portion becomes too large, there is no effect of eliminating the left-right difference such as the extrusion speed by the cylindrical tube portion. Moreover, in the case of the comparative example 2, variation was recognized by the temperature distribution compared with Examples 1-3.

(3) Left and right height difference and gear pump load The honeycomb formed bodies of Examples 1 to 3 and Comparative Example 1 were cut along a direction orthogonal to the extrusion direction, and the cut surface was directed to a predetermined plate surface. In the mounted state, the height of the honeycomb formed body was measured. At this time, the height of the honeycomb formed body at the left and right positions with respect to the extrusion direction of the honeycomb formed body was measured, and the difference in height between the left and right was calculated. According to this, in the case of Examples 1-3, the difference in height between the left and right is about 3 mm or less, whereas in the case of Comparative Example 1, it was 5.2 mm. In other words, it was recognized that a large difference in the shape of the formed body occurred by changing the tube diameter D of the cylindrical tube portion. At this time, although the load which concerns on a gear pump raises slightly compared with the comparative example 1 in Examples 1-3, a practical problem does not generate | occur | produce.

(4) Influence of formed body temperature As shown in FIG. 5, when the average formed body temperature of the honeycomb formed body was set to 25 ° C. or 28 ° C. (Comparative Examples 3 to 7), the difference in height between the left and right sides was 4 It was confirmed that the thickness was 0.0 mm or more and a maximum of 5.6 mm. Thereby, in the extrusion molding apparatus of the present invention, it is necessary to adjust the average molded body temperature of the honeycomb molded body to be at least 32 ° C., in other words, the molding material in the molded portion, the gear pump, and the base portion. It was confirmed that the temperature had to be adjusted.

  As described above, by using a gear pump including a cylindrical pipe portion having a pipe diameter D and a pipe length L in a range defined in the extrusion molding apparatus of the present invention, a honeycomb having a good temperature distribution and a small left-right height difference. A molded body can be formed. In particular, the honeycomb formed body can be formed more stably by adjusting the average formed body temperature to 32 ° C. or higher.

  The extrusion molding apparatus of the present invention can be particularly suitably used in an extrusion molding process for extruding a honeycomb molded body, and enables extrusion of a honeycomb molded body with a stable molded body shape.

DESCRIPTION OF SYMBOLS 1,100,200: Extrusion molding apparatus, 2,107: Molding material, 3,112: Honeycomb molded object, 10,103: Barrel, 11,102: Opening part, 12,106: Transport space, 20,101: Extrusion Screw, 21: Screw shaft, 22: Screw blade, 30, 104: Base part, 31, 113: Base space, 32, 109: Filter net, 33a, 110a: First space, 33b, 110b: Second space, 34 , 111: base, 40, 210: gear pump, 41: inclined tooth, 42a, 42b: inclined gear, 43: gear space part, 43a: introduction port, 43b: outlet port, 44: introduction space part, 45, 211: Supply space section 46: Gear housing section 47: Gear base section 48: Transport space 49a, 49b: Gear space 50: Cylindrical tube section 51: Connection space section 60, 108: Drive device 70 05: material input unit, 212: truncated conical space, A: conveying direction, B: gear shaft, C1, C2: the direction of rotation, D: pipe diameter, L: pipe length.

Claims (3)

A conveying space for conveying the ceramic molding material in the horizontal direction while kneading, and a barrel provided with an opening at one end;
An extrusion screw that is accommodated in the conveying space of the barrel, matches the conveying direction of the molding material and the screw shaft, and is rotatably supported in the conveying space;
A die part that is provided opposite to the opening of the barrel, extrudes the molding material, and forms a honeycomb molded body having an average molded body temperature adjusted to 32 ° C. or higher;
A gear pump interposed between the opening of the barrel and the base and supplying the molding material conveyed to the opening toward the base;
The gear pump is
A pair of inclined gears having a plurality of inclined teeth;
An introductory space that encloses the pair of inclined gears and that can be accommodated, communicates between the opening of the barrel through the inlet of the gear space, and guides the molding material to the gear space. And a gear housing part having a supply space part that communicates between the base part from the outlet of the gear space part and supplies the molding material to the base part,
The supply space is
An extrusion molding apparatus having a cylindrical tube portion extending from the outlet and having a tube diameter of 24 mm or less. The tube length of the cylindrical tube portion from the outlet to the tube end of the cylindrical tube portion is:
The extrusion molding apparatus according to claim 1, which is in a range of 20 to 80 mm.   The extrusion molding apparatus according to claim 1 or 2, comprising a pair of the extrusion screws accommodated in the conveyance space of the barrel and arranged in parallel with the screw shafts being parallel to each other.