JP4491756B2 - Extrusion molding method and extrusion molding apparatus for ceramic honeycomb molded body - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an extrusion molding method and a molding apparatus for extruding a ceramic molded body so as not to be deformed, and more particularly to an extrusion molding method and an extrusion molding apparatus suitable for a ceramic molded body having a thin-walled honeycomb structure.
[0002]
[Prior art]
Conventionally, as a method for extruding a ceramic formed body, a forming method for extruding in a horizontal direction and a forming method for extruding in a vertical direction are used. The horizontal extrusion method is convenient in subsequent settings and easy to automate. On the other hand, if the weight is higher than the strength of the molded body, the molded body will be deformed by its own weight and a product with good dimensional accuracy cannot be obtained. There is a problem.
As a technique for solving this, Japanese Unexamined Patent Publication (Kokai) No. 63-230304 discloses a ceramic extrusion molding method and an extrusion molding apparatus. This extrusion molding method is a lower extrusion molding method in which a ceramic molded body is extruded in the longitudinal direction, and a molded body extruded downward through an extrusion die is held by applying a reaction force in the upward direction. Further, the extrusion molded body is cut into a predetermined length while preventing deformation. As a method for generating the reaction force, a method of controlling the fluid pressure of the plunger that supports the support for holding the molded product while measuring the extrusion length of the molded product or a measurement value proportional to the extrusion length, Is a method for detecting the force applied to the base and controlling the position of the cradle so that the force is proportional to the length of the molded body. As a result, since the weight of the molded body increases as the length of the molded body increases, the pedestal supports the molded body in the vicinity of the die, so that the molded body in the vicinity of the die only has a certain tensile force and does not become deformed due to a narrow diameter. It is stated.
[0003]
[Problems to be solved by the invention]
By the way, honeycomb structure ceramic molded products used for automobile parts and the like are required to be further reduced in size and weight, the outer dimensions are small, the cell density is high, and the wall thickness is thin. In such products, not only the weight of the conventional product is light, but also the ratio of the cross-sectional area to the weight of the conventional product tends to increase, and in the longitudinal extrusion molding, the tensile force acting on the molded body near the die is reduced. Yes. Therefore, the bending or twisting in the axial direction has become a problem rather than the deterioration of dimensional accuracy due to the extension caused by its own weight. This is thought to be due to the fact that the bending of the molded body at the time of extrusion, which occurs due to the difference in the shape of each part of the die through which the slurry passes and the frictional force, etc., can be corrected by its own weight, is no longer possible. .
In the above-mentioned known example, the technical point is how to extrude a molded body having a large self-weight so that the self-weight does not act, and there is no suggestion that there is a problem with one having a weak self-weight.
Therefore, the present invention forms a ceramic molded article, in particular, a ceramic honeycomb molded article for automobiles, which is required to have a strict shape accuracy with a small size and light weight, by vertical extrusion so as not to cause bending and torsional deformation and with high productivity. An object is to provide a molding method and a molding apparatus.
[0004]
[Means for Solving the Problems]
The method for extruding a ceramic honeycomb formed body of the present invention is such that the outer peripheral surface of the ceramic honeycomb formed body extruded downward is regulated by a guide so that the formed body becomes straight, and the bottom of the extruded formed body is The jig is lowered by a movable part provided as a separate body in synchronization with the molding speed of the molded body while supporting the molded body with a cylinder that generates a constant reaction force via a jig with which the end surface comes into contact, A method for extruding a ceramic honeycomb formed body that cuts the formed body to a predetermined length while suppressing lateral displacement of the lower part of the formed body and preventing bending and twisting of the formed body , and the extruded formed body comes into contact with a jig. in the movable portion when the linear sensor of the rod of the cylinder which supports the molded body through the jig is pushed back from its initial position at a certain distance moldings cylinder detects It is characterized in that to start the descent of the ingredients.
[0005]
The ceramic honeycomb formed body extrusion molding apparatus of the present invention regulates the outer peripheral surface of the molding machine for extruding the ceramic slurry downward to form the ceramic honeycomb molded body and the molded body extruded from the molding machine to be straight. Guide, speed detecting means for detecting the molding speed of the molded body, an elevator for supporting the molded body to be extruded and moving up and down, a cutting machine for cutting the extruded molded body in a substantially horizontal state, and each device And a guide is provided near the lower part of the molding machine die, and the elevator is moved in synchronization with the molding speed of the molded body detected by the speed detecting means and controlled to move up and down, and And a cylinder that supports the molded body, which is extruded from the molding machine and is placed on the movable part, and whose lower end surface is in contact with a certain reaction force. The cutting machine is provided below the guide, and is pressed. A moving means capable of controlling the speed in the axial direction and the speed perpendicular to the axis in accordance with the speed; and the cylinder further includes a linear sensor capable of detecting a displacement amount of the rod; A configuration in which the linear sensor measures that the molded body extruded by the molding machine contacts the jig and the rod of the cylinder is pushed back by the molded body from the initial position by a certain distance. Further, the cylinder is further provided as a separate body in the movable part .
[0006]
DETAILED DESCRIPTION OF THE INVENTION
Example 1
As shown in FIG. 1, the basic configuration of the molding apparatus includes a molding machine 1, a jig 3 (3 a, 3 b,...) That supports and places a molded body 2 (2 a, 2 b,...), And a molded body 2. , A guide 4 that supports the outer periphery of the molded body to be straight, an elevator 5 that controls the raising and lowering of the jig 3 that supports the molded body being extruded, a cutting machine 6 that separates the extruded molded body, and a control device (FIG. Not shown).
The molding machine 1 is a vertical pressing type molding machine that extrudes a ceramic slurry downward through a honeycomb-structured die to form, for example, a honeycomb body having a substantially cylindrical outer shape.
The jig 3 is a rectangular plate material having a flat surface, for example, which supports the molded body 2 when being extruded from the molding machine 1 and mounts the molded body after cutting as it is.
[0007]
The guide 4 is provided so as to sandwich the molded body at a position close to the die of the molding machine 1. For example, as shown in FIG. 2, a roller made of an elastic body such as rubber or sponge having substantially the same curvature as the outer diameter of the molded body 2 to be extruded, and its outer circumference rotates in contact with the outer circumference of the molded body 2. Thus, for example, two pieces are provided on the left and right sides of the molded body. Thereby, the bending and twisting of the molded product due to the difference in extrusion resistance when passing through the die are suppressed, and the molded product 2 is regulated to be straight.
[0008]
The elevator 5 includes a vertical movement means whose movable part moves along the extrusion direction of the molded body 2, a vertical compliance means 8 provided on the movable part, and a cradle 9 attached to the compliance means 8. The jig 3 is placed on the cradle 9. The vertical direction moving means has a servo actuator and a rectilinear table 7 as a movable part that is driven by the servo actuator and whose position and speed are controlled. The compliance means 8 has a structure that generates a constant reaction force regardless of the amount of displacement. For example, a low friction type air cylinder connected to a precision pressure control valve or a special spring that generates a constant force can be used. . Hereinafter, an example using a low-friction type air cylinder (hereinafter simply referred to as the cylinder 8) that incorporates a linear sensor and can detect the amount of displacement will be described. A cradle 9 is attached to the rod end of the cylinder 8. The cradle 9 can be translated in the vertical direction by a guide mechanism in accordance with the movement of the rod, and the amount of movement can be measured by a linear sensor built in the cylinder 8.
[0009]
The cutting machine 6 servo-controls a cutting unit stretched so that an extra fine piano wire can cross the molded body in the horizontal direction in the extrusion direction (vertical direction) of the molded body and the transverse direction (horizontal direction) of the molded body. It is something that can be done. Accordingly, even a molded body being extruded can be cut horizontally. The cutting machine 6 is provided below the guide 4 so that the molded body cutting start position is as close to the guide 4 as possible.
[0010]
Further, a sensor 10 for detecting the extrusion speed of the extruded molded body 2 is provided below the die of the molding machine 1. The extrusion speed of the molded body 2 can also be obtained from information from the slurry extrusion means on the molding machine 1 side, but it is desirable to measure the molded body 2 directly because the actual speed can be obtained. As the sensor 10, a non-contact type using a laser can be used. However, as shown in FIG. 2, when the guide 4 of the molded body 2 is a roller, a rotary encoder 15 is attached to the rotating shaft of the roller, You may make it measure based on this rotation.
[0011]
Next, the operation will be described.
First, the initial position of the elevator 5 is set. A predetermined air pressure is applied to the cylinder 8 provided on the rectilinear table 7 to raise the cradle 9 on which the jig 3 is placed, and when it is at the rising end, the initial position of the compliance means is set. Read the sensor value as the origin. In this state, the linear table 7 is moved, and when the upper surface of the jig 3 is at the same level as the position at which the piano wire of the cutting machine 6 starts to cut the molded body 2, the initial position of the vertical movement means is set. The position value of the servo actuator at the time is read and used as the origin. Here, in order to make the later explanation easy to understand, the time when the compliance means and the vertical movement means are at the origin is set as the initial position of the elevator 5. That is, the upper surface of the placed jig 3 coincides with the line of the piano wire at the start of cutting, and the amount of movement from the origin corresponds to the length of the molded body as it is. In addition, the origin of each means and the initial position of the elevator 5 can be appropriately determined based on an arbitrarily determined reference position of the molding machine 1 or the cutting machine 6 without setting the position as described above. Needless to say, you can.
[0012]
In the first molding, the molded body 2a extruded by the molding machine 1 is straightened by the guide 4 and extends downward immediately after exiting the die. After the lower end of the molded body 2a contacts the jig 3a, the molded body 2a is pushed out while the cylinder 8 is pushed back. At this time, the linear sensor value built in the cylinder changes, and the rod movement amount of the cylinder 8, that is, the push-out amount based on the cutting position is measured. Next, when the rod of the cylinder 8 moves by a predetermined value, for example, half of the stroke, the rectilinear table 7 starts to descend in synchronism with the molded body extrusion speed measured by the sensor 10. Thereafter, the rectilinear table 7 descends as the molded body 2 extends.
During this time, even if an error occurs between the actual extrusion speed of the molded body 2a and the moving speed of the rectilinear table 7, the error can be absorbed by moving the rod of the cylinder 8 supporting the molded body 2a up and down. Further, the lower end of the molded body 2a is pressed against the jig 3a with a constant force obtained by subtracting the weight of the cradle 9 and the jig 3a from the output of the cylinder 8, and the lower end of the molded body is cured by the frictional force caused by this. Suppressing from the upper surface of the tool is suppressed, and thus the molded body is prevented from being bent or twisted.
[0013]
When the molded body 2 reaches a predetermined length set, it is cut. The predetermined length can be determined by adding the amount of movement of the rectilinear table 7 and the amount of rod movement of the cylinder 8 and an accurate molded body length can be obtained. Based on the predetermined length detection signal, the cutting machine 6 operates, and the cutting unit operates simultaneously in the horizontal and vertical directions. By controlling the speed in each direction of the cutting unit based on the cutting length of the molded body 2a and the extrusion speed of the molded body, a flat cut surface can be obtained even during extrusion.
[0014]
When the cutting is completed, the rectilinear table 7 descends at a high speed, and the jig 3a on which the molded body 2a cut to a predetermined length is placed is unloaded from the cradle 9. After that, when a new jig 3b is placed on the cradle 9, the rectilinear table 7 rises, stops at a predetermined position, and waits to support the flat lower end of the new molded body 2b continuously extruded. To do. Since the extrusion speed of the molded body 2, the time for replacing the jigs 3a and 3b, and the ascending / descending speed of the linear table 7 can be known in advance, the jig 3b on the linear table 7 immediately before contacting the molded body 2b. The position can be determined and can be raised to this position at high speed. Thereby, the lower end of the molded body 2b can be supported at the earliest possible stage before the molded body 2b reaches a predetermined molding length.
[0015]
As described above, the standby position can be set, and therefore the length of the molded body when the molded body 2b comes into contact with the jig 3b can be known. Henceforth, the molded bodies 2c, 2d. When this happens, the detection signal can be received and cut off. Needless to say, when the lower end of the molded body is supported, the rectilinear table 7 is not necessarily stopped or can be supported at a low speed. The output of the cylinder 8 should be small in order to reduce the impact force when the molded body comes into contact with the jig, but it should be large in order to prevent the molded body from being displaced by the frictional force described above. The air pressure may be adjusted and set as appropriate.
[0016]
Note that the guide 4 has been described as an elastic roller that is provided on the left and right sides so as to press the molded body, but the guide 4 is not limited as long as the structure can regulate the twisting and bending of the molded body. For example, three or more rollers may be provided, may be provided in the vertical direction, or may slide with a molded body instead of a roller, and may be a molded body instead of a mechanical guide. It is good also as a structure which supplies fluid, such as air, to the inside from the cylindrical body which has a predetermined | prescribed clearance gap, and is supported with the pressure.
[0017]
(Example 2)
FIG. 3 shows another molding apparatus equipped with a conveying means that can continuously carry the molded body into, for example, a drying furnace (not shown) in the next step so as to correspond to a more productive ceramic honeycomb body manufacturing process. A configuration example is shown.
As shown in FIG. 3A, two types of elevators 5L and 5R that support a molded body to be extruded are provided on the left and right sides of the paper surface with the extrusion position interposed therebetween. Each elevator has a left-right axis and can move between a position for supporting the molded body to be extruded and a position for carrying the molded body into the drying furnace. The conveying means 11 to the drying furnace is provided with two types (11L, 11R) in the direction perpendicular to the paper surface inherent to the left and right elevators 5L, 5R. FIG. 3A shows a state in which the left elevator 5L is on the left conveying means 11L side to the drying furnace, and the right elevator 5R supports the molded body at the pushing position. FIG. 3B shows the left elevator 5L and its conveying means 11L as seen from the A direction.
[0018]
With reference to FIG.3 (b), a structure and operation | movement of a conveyance means are demonstrated.
The conveying means 11 is provided with a jig stock magazine 12 (12L, 12R) and a roller conveyor 13 (13L, 13R) with an elevator stop position interposed therebetween. A large number of jigs are stacked and stored in the jig stock magazine 12, and the lowermost jig can be pushed out by the extrusion cylinders 14 (14L, 14R). That is, when the elevator 5L is in the lowered position on the conveying means 11L side, the jig pushed out by the pushing cylinder 14L is moved and placed on the cradle of the elevator 5L. Thereby, the jig | tool which has mounted the extruded molded object 2 is extruded from the receiving stand 9, and moves on the roller conveyor 13L. Accordingly, the jig placed on the roller conveyor 13L is conveyed rightward by one jig.
[0019]
The operation of the molding apparatus in this configuration example is as follows. In addition, since it is the same as that mentioned above about supporting and cut | disconnecting the extruded molded object, description is abbreviate | omitted.
When, for example, the molded body 2i molded by the molding machine 1 is cut, the elevator 5L descends at a high speed and moves horizontally to the conveying means 11L side. When stopped at the loading position, the extrusion cylinder 14L is activated, the jig 3j from the jig stock magazine 12L is pushed out and carried onto the elevator, and the jig 3i on which the molded body 2i is placed is placed on the roller conveyor 13L. Move. Thereby, for example, the jig 3e on which the most advanced molded body 2e on the roller conveyor is placed is carried into the drying furnace.
During this time, the other elevator 5R on which the jig is placed moves to the extruded product support position and ascends at a high speed to the predetermined position as described above to support the continuously extruded product. In this way, the extruded body that is cut and free at one end can be quickly supported by the jig.
[0020]
【The invention's effect】
As described above, the present invention has the following effects.
1) Since the outer portion of the molded body is guided immediately after extrusion, the occurrence of bending and twisting can be suppressed.
2) Further, since the lower part of the molded body and the upper surface of the jig are brought into contact with each other with a constant force, a stable frictional force can be obtained and the occurrence of bending and twisting can be further suppressed.
3) By providing two sets of elevators that support the molded body being extruded and using them alternately, it is possible to quickly support a new molded body that has been extruded after cutting, and to support molded bodies with a high extrusion speed, Productivity is extremely high.
[Brief description of the drawings]
1 is a configuration example of the molding apparatus of the present invention. FIG. 2 is a configuration example of a guide in the molding apparatus of the present invention. FIG. 3 is another configuration example of the molding apparatus of the present invention.
DESCRIPTION OF SYMBOLS 1 ... Molding machine, 2 ... Molded object, 3 ... Jig, 4 ... Guide, 5 ... Elevator, 6 ... Cutting machine, 7 ... Straight ahead table, 8 ... Compliance means, 9 ... Receptacle, 10 ... Speed detection sensor, 11 ... Conveying means, 12 ... Jig stock magazine,
13 ... roller conveyor, 14 ... jig extrusion cylinder

Claims (2)

The outer peripheral surface of the ceramic honeycomb molded body that is extruded downward is regulated by a guide so that the molded body becomes straight, and the molded body is fixed to the fixed body via a jig that the lower end surface of the extruded molded body contacts. The jig is lowered by a movable part provided separately as a separate body in synchronization with the molding speed of the molded body while being supported by a cylinder that generates a reaction force, and the lateral displacement of the lower part of the molded body is suppressed, and the molded body is bent. A method for extruding a ceramic honeycomb formed body that cuts the formed body into a predetermined length while preventing or twisting, wherein the extruded formed body is in contact with a jig and supports the formed body via the jig . ceramic honeycomb cylinder rods, characterized in that to start the descent of the jig with the movable portion when the linear sensor of the cylinder that has been pushed back from its initial position at a certain distance molded body is detected Extrusion molding method of the molded body. A molding machine that extrudes ceramic slurry downward to form a ceramic honeycomb molded body, a guide that regulates the outer peripheral surface of the molded body extruded from the molding machine, and a speed detection that detects the molding speed of the molded body Means, an elevator that moves up and down while supporting the extruded body, a cutting machine that cuts the extruded body into a substantially horizontal state, and a control means that controls each device,
The guide is provided near the lower portion of the molding machine die, and the elevator is moved to the movable section that is controlled by the speed detection means and moved up and down in synchronization with the molding speed of the molded body. It has a cylinder that supports the molded body whose lower end surface is in contact with the mounted jig with a constant reaction force, and the cutting machine is provided below the guide, and the axial speed of the cutting tool is perpendicular to the axial speed according to the extrusion speed. The cylinder has a linear sensor capable of detecting the amount of displacement of the rod, and the movable part has a molded body extruded by the molding machine in contact with the jig. and the rod of said cylinder is configured such that the linear sensor that has been pushed back only in the molded body a predetermined distance from the initial position to start the descent when measured, yet the cylinder another to the movable portion It is provided as an extrusion molding apparatus of the ceramic honeycomb formed body according to claim.

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