JP2016150511A - Vertical-type ceramic extrusion molding device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a screw structure of an extrusion molding machine which can reduce a pressurizing action of a screw in an extrusion molding device by a screw-type kneading/feeding device and a vertical-type screw type extrusion molding device as much as possible, significantly improve an agitation action of ceramic clay by a screw, and reduce density ununiformity or physical properties ununiformity due to insufficient agitation of clay as much as possible.SOLUTION: Provided is a ceramic extrusion molding device in which a kneading/feeding machine is connected to a supply port on a top part of a vertical-type extrusion molding machine, a screw 11a of the kneading/feeding machine is made to share a pressurizing action, and a screw 11a of an extrusion molding machine is not made to share a pressurizing action. In the ceramic extrusion molding device, a cutout part 11g is provided for an upper part of the screw 11a of the extrusion molding machine and a screw crest 11ar (reed) of the screw, when the number of cutout parts 11g is n and a spiral direction width of a single cutout part is w, w×n is 20 to 80 mm, and in the case of a plurality of the cutout parts 11g, the cutout parts 11g are arranged on the opposite side with respect to a rotation axis of the screw 11a of the extrusion molding machine.SELECTED DRAWING: Figure 3

Description

  The invention of this application relates to a vertical ceramic extrusion molding apparatus, which makes it possible to stably and continuously form a homogeneous ceramic molded product without stopping the load on the screw of the extrusion molding machine as much as possible. Thus, the structure of the extrusion molding machine can be reduced in size, and the manufacturing cost can be reduced.

The ceramic extrusion molding apparatus is a combination of an extrusion molding apparatus equipped with a mold and a kneading supply apparatus for kneading and supplying ceramic clay to the extrusion molding apparatus. The extrusion molding apparatus is based on a horizontal extrusion system. Are roughly divided into those according to the vertical extrusion method and those according to the plunger type and screw type.
The horizontal extrusion type has a problem that the extruded molded body is deformed (bent) by its own weight, but the vertical extrusion type has no such problem. In addition, the plunger type has a simple and inexpensive structure of the extrusion cylinder, and can easily extrude large products, but is not efficient because the extrusion is intermittent. There is a problem in the quality uniformity and quality stability of extruded products.
Then, the vertical type, horizontal type, plunger type or screw type is selected in consideration of the structure of the molded product, required molding accuracy, molding efficiency, and the manufacturing cost of the extrusion molding apparatus.

Further, the ceramic extrusion molding apparatus is configured such that the kneading supply apparatus and the extrusion molding apparatus are compactly configured by providing the screw of the kneading supply apparatus and the screw of the extrusion molding apparatus on a single rotating shaft (hereinafter referred to as “uniaxial”). For example, Japanese Laid-Open Patent Publication No. 9-94818) and a kneading and feeding device using a screw and an extrusion molding device using a screw are arranged separately, and the kneading and feeding device is arranged in a lateral direction with respect to a vertical extrusion molding device. (Hereinafter referred to as “biaxial type”, for example, Patent Document 2).
The uniaxial type and the biaxial type are such that a ceramic clay kneaded and pressurized by a kneading supply device is continuously supplied to an extrusion molding device, and this is further stirred and kneaded by an extrusion molding device and pressed through a mold. Although there is no difference, the biaxial type can be extruded from the mold by pressing in two stages with a kneading and feeding device and an extrusion molding device, so that a molded product with a complicated and precise structure can be obtained by non-stop high-pressure extrusion. It is easy to mold with high quality and high dimensional accuracy. In addition, the biaxial type is more complicated and large in size than the uniaxial type, and the manufacturing cost is high and the operating cost is high, but the degree of freedom in design is high. Thus, the uniaxial type and the biaxial type have various differences in their advantages and disadvantages.
The ceramic extrusion molding apparatus is based on an extrusion molding apparatus and a kneading supply apparatus for kneading and supplying the ceramic clay to the extrusion molding apparatus, and the extrusion molding apparatus has a mold at the lower end. The kneading and feeding device is a kneading and feeding device, a vacuum degassing device, and a ceramic clay adjusting device. Therefore, an attachment device such as a receiving device that cuts out, conveys, and stores a molded body that is continuously extruded is not included in the “ceramic extrusion device” in this specification.

[Prior art and its problems]
The invention of this application is a screw-type, biaxial, vertical ceramic extrusion molding apparatus. However, as a conventional technique using a plunger-type extrusion molding machine related to the present invention, JP-A-7-32335 (Patent Document 1). There is a thing (refer FIG. 4), and there exists a thing of patent 5578696 (patent document 2) as a prior art by a screw type extrusion molding machine (refer FIG. 5).

1. About the thing of patent document 1 The thing of patent document 1 (FIG. 4) has connected the kneading | feeding supply apparatus 41 to the supply port of the horizontal direction of the plunger type extrusion molding machine 42 (it is hereafter referred to as "prior art 1". Called).
The kneading and feeding device 41 is composed of a screw-type kneading and feeding device 41b, a vacuum degassing device 41c, and a ceramic clay adjusting device 41a. The extrusion molding machine 42 includes an extrusion cylinder 421, a plunger 422, a hydraulic cylinder 423, and a mold 42d. In this case, the extrusion molding is interrupted for each stroke of the plunger 422 of the extrusion molding machine 42, and the ceramic clay is intermittently supplied. Therefore, the kneading supply and extrusion molding of the ceramic clay are repeated intermittently. Therefore, the uniformity of the quality of the molded product is impaired, and the stability of the quality is likely to be impaired.

  Furthermore, in this prior art 1, the ceramic clay kneaded and adjusted is supplied from one lateral supply port of the extrusion cylinder 421 of the extrusion molding machine 42 to which the kneading supply machine 41b is connected. Since it flows while diffusing in the direction (FIG. 4C), the density is non-uniform at point a near the supply port and point b far from the supply port. For this reason, the density distribution of the ceramic clay in the extrusion cylinder 421 becomes non-uniform, and is pushed by the plunger 422 as it is and pushed out from the mold 42d, resulting in variations in the density distribution of the molded body. Becomes unstable. In order to solve this problem, the invention of Patent Document 1 is devised to improve the density distribution by providing a plurality of supply ports symmetrically with respect to the central axis of the extrusion cylinder 42 (see Patent Document 1 for details). ).

2. About the thing of patent document 2 The thing which made the vertical-type extrusion molding machine screw type and was able to perform extrusion molding without a stop is described in patent document 2 (prior art 2).
The prior art 2 (FIG. 5) includes a kneading and feeding device 56 similar to that of the prior art 1. The kneading supply device 56 is based on the upper ceramic clay adjusting device 56a, the lower kneading supply device 56b, and the vacuum degassing device 56c, and the extrusion molding device 57 is based on the cylinder 57a and the screw 57b. And this extrusion molding machine 57 is equipped with the metal mold | die 57c in the lower end, and has the drive device by the electric motor 57d and the transmission 57e in the upper end.

In the prior art 2, continuous extrusion molding at high pressure is performed by two-stage pressurization, that is, pressurization by a screw of a kneading supply device 56b of the kneading supply device 56 and pressurization by a screw 57b of an extrusion molding device 57 of an extrusion molding device. This facilitates high-quality and stable extrusion by high-pressure continuous extrusion (see Patent Document 2 for details).
Since the extruder 57 of the prior art 2 is a screw type, the ceramic clay is pressurized while being stirred by the screw 57b in the cylinder 57a. For this reason, a large residual stress is generated in the ceramic clay due to the strong friction with the screw 57b, and it is strongly influenced by the frictional heat due to the friction with the screw 57b, and this thermal influence has an influence on the quality of the molded product. There is a problem that the residual stress, residual strain, etc. remain large, and the pressure is applied by the screw of the kneading and feeding machine 56b and further by the screw 57b of the extrusion molding machine 57. The problem is that the manufacturing cost of the extrusion molding device (by the extrusion molding machine and its driving device) is high and the maintenance cost is high compared to the vertical plunger type extrusion molding machine of the prior art 1 because of high load. There is.

Problems with the plunger type extruder of the prior art 1, namely, the poor extrusion molding efficiency and the non-uniform density distribution of the ceramic clay in the extrusion cylinder, thereby impairing the homogeneity of the molded product. Can be eliminated by making a screw type following the prior art 2, and by reducing the pressure applied by the screw in the extrusion cylinder at that time, the above-mentioned due to the high pressure and high load of the extrusion molding machine The problem is reduced.
From the above, in order to reduce the problem of high-pressure extrusion molding by the above-described two-stage pressurization method, a method in which the pressurizing action is shared by the screw of the kneading feeder and the pressurizing action is not shared by the screw of the extruder. (Hereinafter, this is referred to as “premise technology” of the present invention).

However, if the mechanism of the mechanism such as making the screw of the extrusion molding machine has a large diameter and a short length and the low-speed rotation control of the screw prevents the pressing action from occurring, the stirring action by the screw will be reduced. As a result, the problem of non-uniform density of ceramic clay and the problem of non-uniform physical properties (hardness, viscosity, fluidity, etc.) remain.
Therefore, in order to effectively solve the above problems, a screw extrusion kneading screw (extrusion screw) is used on the premise of a ceramic extrusion molding apparatus using a screw-type kneading supply device and a vertical screw-type extrusion molding device. Regarding the reduction of pressure action as much as possible, the stirring action of the ceramic clay by the screw is greatly improved so that the non-uniformity of the ceramic clay density and physical properties due to insufficient stirring can be reduced as much as possible. Furthermore, devising the structure of the screw of the extrusion molding machine, this is the technical problem of the present invention.

(1) Technical means The technical means for solving the above-mentioned problem is that a kneading supply machine is connected to the supply port at the top of the vertical extrusion molding machine, and the pressure action is shared by the screw of the kneading supply machine, The following (a), (b), and (c) are based on the premise of a ceramic extrusion molding apparatus that does not share the pressing action on the screw of the extruder.
(A) A defect portion was provided in the thread (lead) at the top of the screw of the extrusion molding machine.
(B) w × n is 20 to 80 mm, where n is the number of missing parts and w is the width in the spiral direction of one missing part.
(C) When there are a plurality of defect parts, the defect parts are arranged on the opposite side to the rotation axis of the screw of the extrusion molding machine.
“Screw upper part” means an upper part of the middle part of the screw and means a part close to the ceramic clay supply port.

(1) -1. Action Since the thread 11ar is provided with a defect 11g in the upper part of the screw 11a of the extrusion molding machine, the ceramic clay pushed from the kneading and feeding machine is taken into the upper part of the screw and the screw groove 11ag of the screw. Flows down. Then, a part of the flow f2 becomes a flow f3 passing through the defect 11g and above the screw thread 11ar, and the flow f3 above the screw thread flows in the screw groove 11ag above the screw thread f1. And the ceramic clay is entangled and dragged around the defect 11g, so that the stirring action is enhanced at the top of the screw.
Therefore, even if the screw 11a of the extrusion molding machine hardly generates a pressurizing action, the required stirring action can be achieved.

Further, the helical direction width w and number n of the defect portion 11g are the hardness and viscosity of the ceramic clay, the structure of the extrusion screw (screw outer diameter, height, pitch, etc.), the rotation speed (or unit) of the extrusion screw. The optimum value cannot be determined unconditionally because it varies depending on various conditions such as the processing amount per hour. Therefore, there is no other way than selecting appropriately according to the design conditions of each extrusion molding machine. If the width w × number n is less than the range of (b) above, the flow f3 that escapes above the thread is insufficient, and conversely if it exceeds the range, the flow f3 becomes excessive and feeds forward. The action is greatly reduced and unstable. When the above w × n is within the above range, practically necessary feeding action and stirring action can be obtained.
Further, when there are a plurality of deficient portions 11g, they are arranged on the opposite side with respect to the rotation axis of the screw, so that the stirring resistance and extrusion resistance are balanced over the entire circumference of the screw, and the stirring action and feeding action by the screw are It is made smoothly.
Refer to FIG. 3 for symbols (f1, f2, f3, 11g, etc.) in the description of the above operation.

(2) Embodiment (2) -1. Embodiment 1
Embodiment 1 is based on the following solution (d) (e).
(D) When the height of the thread of the screw of the extrusion molding machine is H, the depth h of the defect portion is set to h = 0.5 to 1.0H.
(E) The cut surface of the thread of one defect portion is a cut surface perpendicular to the rotation axis of the screw of the extrusion molding machine.

(2) -2. Embodiment 2
The second embodiment is based on the following means (1) or (2) on the premise of the above solution or the first embodiment.
(F) the screw thread of the extrusion molding machine is a double thread symmetrical to the rotational axis of the screw;
(G) The shape of the flow path formed by the defect portion is a quadrangle.

(2) -3. Operation of the embodiment Since the above-mentioned defect portion is provided in the upper part of the screw, there is no hindrance to the metering operation of the screw that stably feeds the ceramic clay to the mold at a predetermined speed, and the screw rotational speed is adjusted. By doing so, the extrusion speed is adjusted.
It should be noted that as the depth h of the defect portion 11g with respect to the height H of the screw thread is shallower, the above action by the defect portion, that is, the stirring action due to the entanglement of the flow extending upward of the screw thread and the ceramic clay (ceramic iron along the screw groove). The agitation action on the upper layer and lower layer of the soil flow is low, but if the depth h with respect to the height H is 50% or more, it is quite effective.

Further, if the depth h of one deficient portion is less than the range of (d) above, the flow f3 that escapes above the thread will be insufficient, and the stirring action by this will not reach the lower layer, and the ceramic clay Although it does not reach the entire flow, if it is within the above range, the same stirring action can be exerted on a wide range of the ceramic clay flow.
Further, since the flow path formed by the defect portion 11g rotates in a plane perpendicular to the rotation axis due to the above (e), the ceramic clay smoothly flows into the defect portion of the screw thread, and therefore the flow f3 is effective. Has a stirring action.

  As for the screw (extrusion screw) of the extrusion cylinder, it is well known that it is based on one thread or two threads, and which one to use is appropriately selected in consideration of the advantages and disadvantages of these screws. Although it is possible, this invention is applicable also to the thing by one thread, and there exists an expected stirring action. However, in order to uniformly exert the stirring action on the entire ceramic clay fed by the screw, it is preferable to use two threads as described above.

[About the shape of the channel and the channel area of the defective part]
About the "defect part" in the description of the above solution means and embodiments, it is assumed that the screw thread is cut with a lathe and has a substantially rectangular channel shape. In this way, a desired upward diversion flow f3 is generated in the ceramic clay flowing through, and, from this, it should not be a square flow path, but the inverted triangle and trapezoid can also have the desired effect. be able to. Therefore, the shape of the flow path by the defective portion may be an inverted triangle or a trapezoid, but in this case, the flow path area of the diversion f3 may be almost the same as that of the square shape.
Although it is as described above, it is desirable that the ceramic clay flow that flows along the thread groove is equally divided in a wide range from the upper layer to the lower layer, and in this sense, the shape of the flow path is preferably a square shape, In the case of cutting by a lathe, a rectangular shape is preferable because it is easy to process and the flow into the defect portion is smooth.

Since a hollow cylindrical molded product having a large diameter (for example, 300 mm) such as a honeycomb structure is suitable for extrusion molding at a relatively low pressure, the present invention efficiently and continuously performs ceramic molding products having a uniform density. Suitable for mechanical molding.
In the extrusion molding machine according to the present invention, since the extrusion screw does not bear the pressurizing action but the stirring and the extrusion action, the screw length is very short (for example, 1.25 to 2. Because the rotation speed can be controlled at a low speed, the electric motor for driving, the speed reducer, etc. can be reduced in size, and the frictional heat generated between the ceramic clay in the extrusion molding machine and the extrusion screw can be generated. Therefore, the power consumption for extrusion molding is reduced, and the load for cooling the extrusion cylinder is reduced.
From the above, the manufacturing cost of the vertical ceramic extrusion molding apparatus can be greatly reduced, and the operating cost can be greatly reduced.

Moreover, the stirring means by the thread | thread defect | deletion part of the screw upper part is provided in the thread of the extrusion screw, and is a part of the extrusion screw.
Therefore, a special stirring means is not provided separately from the extrusion screw, and therefore, it is not necessary to lengthen the shaft of the extrusion screw. Therefore, there is no problem that the length of the shaft increases and the extrusion cylinder becomes large.
In addition, since a defective portion can be formed by cutting off a part of the thread by lathe processing, the forming process is extremely easy.

  Furthermore, since a part of the screw is provided with a defect part, a part of the ceramic is shunted into the screw groove above, and the ceramic clay entangled with the defect part is stirred by dragging with the rotation of the screw. For example, the stirring is gentle and the resistance is small as compared with the case of stirring by the shearing action of the stirring blade. Therefore, the drive motor output does not increase due to the stirring resistance, and the heat generated by the stirring is small, so the cooling load on the extrusion cylinder does not increase.

Is an overall front view of an embodiment of the present invention FIG. 7 is a front view showing an outline of an attachment device such as a reception and its operation. FIG. 7A shows a state in which the attachment device such as reception is raised, FIG. 5B shows a state in the middle of lowering, and FIG. (A) is a side view schematically showing a relationship between an accessory device such as a receiver and a conveyor, and (b) is a front view of the same. (A) is a front view of a screw of an extrusion molding device, (b) is a perspective view, and (c) is an enlarged view in which a thread defect is enlarged. (A), (b) is the front view which shows typically the whole prior art 1, (c) is explanatory drawing which shows typically the density distribution in the extrusion cylinder of the ceramic clay supplied to an extrusion cylinder. Is a longitudinal sectional view schematically showing the entire prior art 2

Next, examples will be described with reference to FIGS. 1, 2, 2-1, and 3.
In this embodiment, a honeycomb structure (for example, DPF (diesel particulate collection) having an outer diameter of 300 mm by a vertical and screw type extrusion molding apparatus 1 and a kneading and feeding apparatus 2 for continuously kneading and adjusting ceramic clay. This is an example in which the present invention is applied to an extrusion molding apparatus that extrudes a filter) continuously without stopping.
The “extrusion molding device”, “accepting device for receiving”, “screw structure” and the like in this embodiment will be described in order.

1. Ceramic extrusion apparatus 1-1. Mechanism The ceramic extrusion molding apparatus is composed of a vertical extrusion molding apparatus 1 using a single extrusion screw and a kneading supply apparatus 2. The kneading supply device 2 includes a kneading supply device 21, a vacuum degassing device 22, and a ceramic clay adjusting device 23 connected to a supply port in the upper part of the cylinder 11c of the extrusion molding device 1. A molding die D is provided at the lower end of the mold.

[Extrusion molding equipment]
The extrusion molding apparatus 1 includes an extrusion molding machine 11 and a driving device 12.
An extrusion molding machine 11 of the extrusion molding apparatus 1 includes a cylinder 11c having an inner diameter of 256 mm, an extension pipe 11d, a resistance pipe 11e, and a single screw 11a having a length of about 430 mm. The lower end of the resistance pipe 11e The molding die D is attached to. And the number of rotations per minute (specification) is 1 to 11 times, and the extrusion pressure (specification) is 200 kg / cm ² or less, but the actual extrusion pressure is the size of the molded product p to be extruded and It depends on the structure, the physical properties (hardness, viscosity, etc.) of the ceramic clay, and the molding speed, and the rotational speed of the screw 11a varies depending on the physical properties of the ceramic clay and the required molding speed.
The mold D can be replaced according to the shape structure of the molded body p, and is mounted in the mold casing 11f. The mold casing 11f is detachably attached to the lower end of the resistance tube 11e. Yes. And the resistance board 11b is provided in the substantially intermediate part of the metal mold | die D and the screw 11a. The resistance plate 11b is a stainless steel plate having a large number of small holes. The diameter of the small hole is larger as it is closer to the inner surface of the cylinder 11c and is smaller as it is closer to the center, thereby producing an effect of making the ceramic clay flow in the cylinder 11c uniform.

[Kneading feeder]
The kneading supply device 2 includes a kneading supply device 21, a vacuum degassing device 22, and a ceramic clay adjusting device 23.
The kneading and feeding device 21 of the kneading and feeding device 2 includes a cylinder having an inner diameter of 101.5 mm and a single screw 21a having a length of 1400 mm. Between the feeding port of the cylinder 11c of the extruder 11 and the tip of the screw 21a. There are a resistance plate 21b and a filter 21c.
The screw 21a rotates at a rate of 3 to 33 times per minute (specification), whereby the ceramic clay is pressurized while being kneaded and fed to the extruder 11 at a constant speed. The filter 21c is a stainless steel filter, and the resistance plate 21b is a stainless steel disk having a large number of small holes (for example, a diameter of 5 mm). The resistance plate 21b is a support plate for the filter 21c and has an effect of making the flow of the ceramic clay uniform. In the ceramic clay, foreign matter of 100 μm or more is captured by the filter 21c of the kneading and feeding machine 21, and is sent to the supply port on the upper side of the cylinder 11c of the extrusion molding machine 11 through the resistance plate 21b.

[Ceramic clay adjusting device]
The ceramic clay adjusting device 23 of the kneading and feeding apparatus 2 is a cylinder having an inner diameter of 60 mm and a single screw. The ceramic material and additives are stirred to adjust the ceramic clay, and the vacuum deaerator 22 is used. Is to deaerate.
And this is arrange | positioned above the kneading supply machine 21, is connected to the rear part of the kneading supply machine 21 via the vacuum deaeration apparatus 22, and the hopper 23a which supplies a ceramic raw material etc. in the rear part is provided. ing. Then, the ceramic material and the additive added to the ceramic clay adjusting device 23 from the hopper 23a are stirred by the screw, sent to the vacuum degassing device 22, degassed, and taken into the kneading supply machine 21. The kneading is adjusted, pressurized and fed into the extrusion molding machine 11.

1-2. Operation The ceramic clay is adjusted by the ceramic clay adjusting device 23, degassed by the vacuum degassing device 22, and supplied to the kneading feeder 21. Then, pressure is applied while being kneaded by the screw 21a of the kneading and feeding machine 21, foreign matter of 100 μm or more is captured by the filter 21c, passes through a small hole in the resistance plate 21b, and is placed above the cylinder 11c of the extruder 11 (screw 11a). To the top).
And the ceramic clay supplied to the upper part of the cylinder 11c of the extrusion molding machine 11 is taken in by the screw 11a of the extrusion molding machine 11, and is pushed downward to be pushed out of the molding die D so that the ceramic molded body p is formed. Molded.
The screw 11a of the extrusion molding machine 11 has a large diameter and rotates at a low speed, and the screw 21a of the kneading supply machine 21 has a small diameter and rotates at a higher speed than the screw 11a of the extrusion molding machine 11. The screw 21a kneads and pressurizes the ceramic clay and feeds it into the cylinder 11c of the extrusion molding machine 11. The screw 11a of the extrusion molding machine 11 pushes out the ceramic clay from the mold D while stirring the ceramic clay. The extrusion speed (molding speed) from the mold D at this time is adjusted by controlling the rotational speed of the screw 11a.

The cylinder 11c of the extrusion molding machine 11 is hermetically sealed, the screw 11a has a large diameter and a short length (in this embodiment, the thread pitch number is 1.75), and is mainly intended for stirring ceramic clay. There is almost no pressurization by this, and the upper inlet side internal pressure and the lower outlet side internal pressure are substantially equal. On the other hand, the screw 21a of the kneading and feeding machine 21 has a small diameter and a long length, and exhibits stirring and kneading and a strong pressurizing action.
Further, as described above, since the screw 11a of the extrusion molding machine 11 is intended for stirring, a part of the ceramic clay is not remarkably heated by friction with the screw 11a. The effect of significant heating is greatly reduced.

1-3. Extrusion speed and molding accuracy, etc. Since the extrusion speed of the extruder 11 is substantially proportional to the rotational speed of the screw 11a (but not linearly proportional in the high pressure region), the rotational speed of the screw 11a is controlled, Further, the rotational speed of the screw 21a of the kneading and feeding machine 21 is controlled so as to be extruded at a required pressure.
Since the physical properties (plasticity, fluidity, viscosity, etc.) of the ceramic clay greatly affect the forming accuracy, this physical property must be stable. For this purpose, the ceramic clay is agitated by the ceramic clay adjusting device 23 and kneaded by the kneading supply machine 21 so that the physical properties thereof are appropriately adjusted.
Moreover, since the extrusion speed (extrusion pressure) of the ceramic clay greatly affects the forming accuracy, these must be controlled stably, and the extrusion molding machine is used to stabilize the extrusion speed of the ceramic clay. 11 and the rotation speed of the screw 21a of the kneading and feeding machine 21 are controlled.

1-4. Control of Extrusion Molding Speed The rotational speed of the screw 11a of the extrusion molding machine 11 is controlled according to each molded product on the premise that the physical properties of the ceramic clay are adjusted to a predetermined level and supplied to the extrusion molding apparatus 1. The
The ceramic clay is stirred by the ceramic clay adjusting device 23, kneaded and pressurized by the screw 21 a of the kneading and feeding machine 21, and supplied to the extrusion molding machine 11. The ceramic clay supplied to the extruder 11 is agitated by the screw 11a to make the density uniform, and the resistance plate 11b makes the flow (the outer peripheral portion and the internal flow in the cylinder) uniform. Sent to type D.

2. Attached equipment such as receipt
2-1. Mechanism Since the molded product p extends downward in the vertical extrusion molding device, the elongated molded product p does not deform (curve or the like) due to its own weight as in the horizontal extrusion molding device, and the internal distortion caused by the deformation. Will not occur. However, in the case of a vertical extrusion molding apparatus, a downward pulling force is applied to the elongated molded body p due to its own weight, which causes internal strain in the vertical direction. Therefore, the lower end of the molded body p is supported by a molded body holding means such as a tray, and the holding device is lowered in synchronization with the expansion of the molded body to prevent distortion due to its own weight. When it is stretched, it is cut at a position immediately below the molding die D to cut a molded product p1 of a predetermined height (for example, a large honeycomb structure having a diameter of 300 mm, such as the above-mentioned DPF or DOP (diesel oxidation catalyst)). It is necessary to accommodate this safely. The receiving device 4 is for this purpose.

The raising / lowering drive mechanism of the molded body holding means of the attachment device 4 such as the receiving and its raising / lowering control are well-known matters (this point is provided by the prior arts of Patent Documents 1 and 2, and is known to those skilled in the art. Although it is common sense, please refer also to Unexamined-Japanese-Patent No. 2003-311726 if necessary, and since this point is outside the summary of this invention, the detailed description is abbreviate | omitted and the outline | summary is demonstrated.
The receiving and other accessory device 4 has a setter table 10 supported by four front and rear, right and left four columns 4p so as to be movable up and down, and a cutting machine 4a is attached to a support frame of the setter table 10.
A setter (such as a saucer) 10a is mounted on the setter table 10. In this state, the setter table 10 and the cutting device 4a are raised (FIG. 2A), and the lower end of the extending molded body p is supported by the setter 10a.
When the setter table 10 is lowered to the supply conveyor C1 (FIG. 2C), the setter 10a on which the molded product p1 is placed is sent to the receiving conveyor C2 and replaced with a new setter 10a.
The setter table 10 includes a load sensor s. The load sensor detects a load (weight) due to the molded body p on the setter 10a and transmits a load signal corresponding to the magnitude of the load to the control device. Then, the control device controls the lowering and lowering speed of the setter table 10 according to the load signal.

[Cutting device]
Further, the cutting device 4a is well known in the art and is known in various mechanisms (this is well known and commonly used, not to be exemplarily shown, and is common knowledge of those skilled in the art, but is necessary. For example, see the well-known example above). Since the details of the cutting device 4a are outside the scope of the present invention, the details thereof will be omitted and the outline will be described.
The cutting device 4a repeatedly cuts and cuts the ceramic molded body p in the horizontal direction with a wire cutter c, and has a wire driving device that winds the wire around a reel and runs it in the longitudinal direction. A reciprocating drive mechanism for reciprocating the device in the horizontal direction is provided. By moving the wire in the longitudinal direction while running in the longitudinal direction, the molded body p is horizontally cut by the wire, and a molded product p1 having a predetermined height is cut out (FIG. 2B).
In addition, since the cutting device 4a by this wire cutter c is a conventionally well-known thing, the detailed description is abbreviate | omitted. If necessary, refer to Patent Documents 1 and 2 and the above-mentioned well-known documents.

〔Conveyor〕
The conveyor is a supply conveyor C1 that supplies the setter 10a to the setter table 10 and a receiving conveyor C2 that receives the molded product p1 together with the setter 10a, and is a general belt conveyor and a roller conveyor. These operations are controlled in conjunction with the lifting and lowering operation of the accessory device 4 such as receiving.

2-2. Operation In a state where the extrusion molding by the mold D is continuously performed, the setter table 10 to which the setter 10a is attached is raised to a predetermined position, and the lower end of the molded body p is supported by the setter 10a. And if the load concerning the setter 10a by the molded object p becomes more than predetermined, this will be detected by the load sensor s of the setter table 10, the raising / lowering device will operate | move with the detection signal, and the setter table 10 will fall. The descending speed at this time is controlled in accordance with the magnitude of the load signal (same as the load amount of the load sensor) by the load sensor s, and the descending of the setter table 10 is controlled so that the load is maintained constant. . This prevents distortion due to its own weight from occurring in the molded body p.
Then, when the setter table 10 descends to a predetermined position as the molded body p extends, this is detected by an appropriate position sensor, and the cutting device 4a is activated by the detection signal to cut at a predetermined height (FIG. 2). (B)). When the molded product p1 is cut off, the setter table 10 is quickly lowered to a predetermined position.

  The time required to cut the molded body p by the cutting device 4a varies depending on the thickness of the molded body p, the density of the internal structure thereof, and the like. For example, the PDF honeycomb structure of the PDF having a diameter of 300 mm is used. In this case, the required time is about 40 seconds. On the other hand, the lowering of the setter table 10 is controlled by the load detection signal of the load sensor as described above, and the cutting device 4a is lowered together with the setter table 10. Since the setter table 10 is not displaced in the vertical direction relative to the molded product p within the required time, the cutting by the cutting device 4a is made horizontal, and the cut surface is smooth.

When the molded product p is cut by the cutting device 4a and the molded product p1 having a predetermined height is cut out, this is detected, and the lowering control of the setter table 10 is switched to promptly descend to the position of the receiving conveyor C2. Then, the setter 10a on which the molded product p1 is placed is sent out to the receiving conveyor C2, and the next setter 10a is supplied from the supply conveyor C1 to the setter table 10. Then, the setter table 10 quickly rises to a predetermined position at a predetermined speed, and after that, the lower end of the molded body p is supported by the setter 10a again and begins to descend again by the load signal of the load sensor s, and the load applied to the setter 10a is constant. The descent is controlled so that
Since the above operation is repeated, the molding of the ceramic molded body p and the cutting of the molded product p1 are continuously performed without stopping.

  As for the lowering control of the setter table 10, the molding speed (elongation speed) of the molded body p can be measured, and the lowering of the setter table 10 can be controlled based on this molding speed signal. It is well known to control the lowering speed of the material in synchronization with the molding speed, and one in the prior art 2 (Patent Document 2) is an example.

3. The structure of the screw of the extrusion molding machine The above is the whole of the embodiment of the present invention. Next, features of the present invention will be described.
The feature of the present invention is the structure of a screw (vertical screw) 11a in a vertical extruder (also simply referred to as “vertical extruder”). The structure of the screw 11a is as shown in FIG. 3, which is based on two axially symmetrical threads 11ar (double thread), whose outer diameter is 250mm, and the height H of the thread is 50mm. The thread thickness is 22 mm and the thread pitch is 120 mm. The effective length L of the screw 11a is 310 mm, and the pitch number is 1.75.

A deficient portion 11g is provided at a position below the upper end of each screw thread 11ar of the screw 11a by about 1/2 pitch (1/2 lead) (upper screw). The defect portion 11g is formed by upper and lower cut surfaces perpendicular to the rotation axis of the screw, and the width of the defect portion 11g (that is, the width of the defect portion in the screw thread direction) w is 20 mm and the depth h. Is 50 mm which is equal to the height of the thread.
The screw 11a rotates counterclockwise, and is pushed downward by the thread 11ar by this rotation, so that the ceramic clay flows downward spirally in the thread groove 11ag (this flow is the mainstreams f1 and f2. reference). At this time, since the defect portion 11g rotates in the horizontal direction, a part of the flow f2 of the screw groove 11ag on the lower side of the screw thread 11ar flows into the defect portion 11g and is divided into the upper screw groove 11ag. This divided flow f3 becomes a flow to the upper main flow f1 and joins and mixes with the main flow f1.
For example, when extruding the above-mentioned PDF honeycomb structure having a diameter of 290 mm and a wall thickness of 0.16 mm, the screw 11 a uses the inlet side pressure of the cylinder 11 c of the extruder 11 (the same as the supply pressure by the kneading supply device 21). ) Is 58 kg / cm ² and the outlet side pressure (extrusion pressure) is 53 kg / cm ^2. For example, a ceramic having a hardness of 12 (according to a hardness meter of Nippon Glass Co., Ltd.) is 50 mm / min. It can be extruded at a speed. And the variation in the hardness of the molded object p extruded from the metal mold | die D and the variation in a density are very small compared with the case where it is based on the conventional screw without the defect | deletion part 11g.
The screw 11a can be implemented with either one thread or three threads, but as the number of threads increases, the width of the thread groove becomes narrower. descend. Therefore, there is no special advantage by being 3 articles or more.

4). About Other Items The present invention is most effective when applied to an extrusion screw that does not exhibit the pressurizing action of a biaxial extrusion molding apparatus. Even if it is to be performed, the stirring action is similarly achieved by providing the stirring means by the defect portion 11g. This is because the ceramic is gently stirred as soon as it is taken into the thread groove, and then kneaded and pressurized and sent to the mold.
For the same reason, it can be applied to the screw 21a of the kneading and feeding machine 21 and is effective.

JP-A-7-32335 Japanese Patent No. 5578696

1: Extrusion molding device 11: Extrusion molding machine 11a: Screw (extrusion screw)
11ar: Screw thread 11ag: Screw groove 11b: Resistance plate 11c: Cylinder 11d: Extension pipe 11e: Resistance pipe 11f: Mold casing 11g: Deficient part 2: Kneading feeder 21: Kneading feeder 21a: Screw (kneading screw)
21b: Resistance plate 21c: Filter 22: Vacuum deaeration device 23: Ceramic clay adjustment device 23a: Hopper 4: Attaching device 4a: Cutting device 4p: Strut 10: Setter table 10a: Setter c: Wire cutter C1: Supply Conveyor C2: Receiving conveyor D: Mold (molding mold)
f1, f2: Mainstream of ceramic clay (flow along screw groove)
f3: Shunt flow to defect part of ceramic clay H: Height of screw thread h: Depth of defect part L: Effective length of screw p: Molded body p1: Molded product s: Load sensor w: Width of defect part ( Width in spiral direction)

Further, the helical direction width w and number n of the defect portion 11g are the hardness and viscosity of the ceramic clay, the structure of the extrusion screw (screw outer diameter, height, pitch, etc.), the rotation speed (or unit) of the extrusion screw. The optimum value can not be determined unconditionally because it varies depending on various conditions such as the processing amount per hour. Therefore, there is no other way than selecting the spiral direction width w and the number n in accordance with the design conditions of the individual extruders.
On the other hand, if the width w × number n is less than the range (b), the flow f3 that escapes above the thread is insufficient, and conversely if the width w is greater than the range, the flow f3 becomes excessive and the forward direction is increased. The feeding action is greatly reduced and becomes unstable. However, when w × n is within the above range, the actually required feeding action and stirring action can be obtained.
Therefore, in each machine design, the above w × n may be appropriately selected within the above range.
Further, when there are a plurality of deficient portions 11g, they are arranged on the opposite side with respect to the rotation axis of the screw, so that the stirring resistance and extrusion resistance are balanced over the entire circumference of the screw, and the stirring action and feeding action by the screw are It is made smoothly.
Refer to FIG. 3 for symbols (f1, f2, f3, 11g, etc.) in the description of the above operation.

Claims (4)

In a ceramic extrusion molding apparatus in which a kneading supply machine is connected to a supply port at the top of a vertical extrusion molding machine,
Provide a deficient part in the thread (lead) above the screw of the vertical extrusion molding machine,
When the number of the defect parts is n and the spiral direction width of one defect part is w, w × n is 20 to 80 mm,
A ceramic extrusion molding apparatus, wherein when there are a plurality of the defect portions, the defect portions are arranged on the opposite side to the rotation axis of the screw. A ceramic that has a kneading and feeding machine connected to the supply port at the top of the vertical extrusion molding machine, sharing the pressing action with the screw of the kneading feeding machine, and not sharing the pressing action with the screw of the vertical extrusion molding machine In extrusion equipment,
Provide a deficient part in the thread (lead) above the screw of the vertical extrusion molding machine,
When the number of the defect parts is n and the spiral direction width of one defect part is w, w × n is 20 to 80 mm,
A ceramic extrusion molding apparatus characterized in that when there are a plurality of defect parts, the defect parts are arranged on the opposite side to the rotation axis of the screw of the extrusion molding machine. When the height of the thread is H, the depth h of the defect is h = 0.5H to 1.0H.
2. The ceramic extrusion molding apparatus according to claim 1, wherein the cut surface of the thread of the defective portion is a cut surface perpendicular to the rotation axis of the screw. The thread is a double thread symmetrical to the rotational axis of the screw,
2. The ceramic extrusion molding apparatus according to claim 1, wherein the shape of the flow path by the defective portion is a quadrangle.

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