JPH08300438A - Heat displacement type t-die - Google Patents

Abstract

PURPOSE: To prevent the generation of trouble caused by the dragging of the threading part of a heat displacement member with a die bolt within a wide temp. region by differentiating the pitch of the screw threaded with a die bolt of a nut from that of the screw threaded with the heat displacement unit thereof. CONSTITUTION: A heat displacement unit 2 is fixed to a projection part 9 by an attaching lock nut 12. A die bolt 1 is inserted in the through-hole 8 of the heat displacement unit 2 and the lower end part thereof is threaded with a flexible lip 5 to be fixed by a lock nut 13. Next, a nut 3 is threaded with the die bolt 1 and the upper part of the heat displacement unit 2. The screws of the die bolt 1 and heat displacement unit 2 threaded with the nut 3 are formed into the so-called differential screw wherein a screw direction is same but a screw pitch is different. By this constitution, the axial relative position of the die bolt 1 and the heat displacement unit 2 is changed when the nut 3 is screwed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a film / sheet forming machine, and more particularly to improving the performance and reliability of a thermal displacement type automatic die actuator used in a profile control system for the thickness of a film sheet. Is.

[0002]

2. Description of the Related Art A plurality of thermal displacement units provided in the width direction of a lip gap are respectively controlled, and thermal expansion or thermal contraction thereof is transmitted to a flexible lip through a die bolt to adjust the lip gap. As a typical one,
U.S. Pat. No. 3,940,221 is well known.

However, in the above apparatus, when the die bolt is heated and extended, the flexible lip is pushed and the lip gap is narrowed to reduce the flow rate of the molten resin, but the heat from the heater for heating the die bolt is reduced. Or it is transmitted to the molten resin side flowing through the lip gap through the die body,
The flow rate is increased by lowering the viscosity of the molten resin by heating the molten resin. Conversely, when the die bolt contracts, the lip gap widens and the flow rate of the molten resin increases, but on the other hand, as the temperature of the molten resin decreases, the viscosity increases and the flow rate of the molten resin decreases. There was a possibility that the flow rate change due to the flow rate change and the flow rate change due to the viscosity change would interfere with each other in the direction of weakening each other. Hereinafter, this system is referred to as a thermal direct drive type.

In order to solve the above problems, a thermal displacement type T-die described in Japanese Patent Publication No. 6-8023 previously filed by the applicant of the present application (hereinafter sometimes referred to as a first prior art example). There is. FIG. 5 is a sectional view of the thermal displacement T-die. In FIG. 5, when the thermal displacement unit 101 whose one end is screwed to the die body is heated by the heater 102, the thermal displacement unit 101 extends to the free end side, and accordingly, the thermal expansion coefficient is at least the same as that of the thermal displacement unit 101 or more. The die bolt 103 made of a small material moves upward while acting in the direction of pulling up the screwed flexible lip 104, so that the flexible lip 104 bends upward in the drawing and the lip gap 105 becomes wide. The flow rate of molten resin increases. At that time, since the flexible lip 104 receives heat via the die bolt 103 and rises in temperature, the temperature of the molten resin increases, the viscosity of the molten resin decreases, and the flow rate increases.

On the other hand, when the power supply to the heater 102 is cut off, the thermal displacement unit 101 is cooled, and accordingly, the die bolt 103 pushes the flexible lip 104 downward in the drawing. This narrows the lip gap 105,
As the flow rate of the molten resin decreases, the molten resin itself is also cooled and the viscosity increases, which works in the direction of decreasing the flow rate. As a result, the effect of the flow rate change due to the lip gap 105 and the effect of the flow rate change due to the viscosity change act in a mutually reinforcing direction, so that profile adjustment can be performed easily and precisely. Hereinafter, this method is referred to as a thermal differential method.

In the above conventional technique, the die bolt 10 is used.
In addition to the case of screwing 3 into the flexible lip 104, a method of simply pressing the die bolt 103 against the flexible lip 104 is also proposed, but the effect is that the die bolt 103 and the flexible lip 104 are combined. There is a difference in the value of pulling up the flexible lip 104 upward when the thermal displacement unit 101 is heated by the heater 102, as compared with the case where the thermal displacement unit 101 is fixed by screwing, but the other operations are the same.

FIG. 6 shows an example of the second prior art.
It is sectional drawing of the thermal displacement type | mold T die which the applicant of this application applied previously and is described in Japanese Utility Model Publication No. 5-40992. The conventional technique is a modification of the conventional technique described above.
As shown in FIG. 5, a bottomed hole 202 opening to the upper end of the die bolt 201 is formed at the axial center of the die bolt 201, and a lateral hole 203 communicating with both side surfaces of the die bolt 201 is formed at the bottom of the bottomed hole 202. The air supply pipe 204 for feeding cooling air is embedded in the thermal displacement unit, and the air supply pipe 2
Die bolt 2 drilled from 04 to thermal displacement unit 205
A horizontal hole 206 reaching the position facing the horizontal hole 203 on the inner surface of the 01 insertion hole is provided.

The thermal displacement unit 205 configured as described above
Is heated by the heater 207, thermally expands, and expands upward, supplying air to the air supply pipe 204. The sent air rises through the horizontal holes 206 and 203 in the hole 202 formed in the axial center of the die bolt 201 and is discharged to the outside. As a result, the die bolt 201 is cooled and the thermal expansion amount becomes smaller than the thermal expansion amount of the thermal displacement unit 205.
The flexible lip 208 is accurately bent upward to widen the lip gap 209 and increase the flow rate of the molten resin.

Flexible lip 20 through die bolt 201
The heat transferred to No. 8 or a small amount of heat transferred from the thermal displacement unit 205 to the die body raises the temperature of the molten resin, lowers its viscosity, and acts to increase the flow rate of the molten resin. On the other hand, when the power supply to the heater 207 is cut off, an action opposite to the above occurs, and the flow rate of the molten resin decreases.

In the thermal displacement type T-die in the above-mentioned first and second prior arts, the applicant of the present invention uses the engineering ceramics whose die expansion coefficient is remarkably smaller than that of steel. , A method is proposed in which the flow passage cross-sectional area of the lip gap is further increased when the thermal displacement unit is heated by the heater, while the flow passage cross-sectional area of the lip gap is accurately reduced when the heater is de-energized (Act 5). No. 40993. Hereinafter, it may be referred to as an example of the third related art.).

[0011]

As described above, also in the first to third prior arts, the effect of the flow rate change due to the lip gap and the effect of the flow rate change due to the viscosity change are exerted in the direction of mutually reinforcing each other. It was possible to make the adjustment easier and more precise than before. However, the above conventional techniques still have the following problems to be solved.

Since the screwing portion between the thermal displacement unit and the die bolt is a direct-acting screw type, the advance amount of the screw corresponding to the minimum angle that can be operated by the operator becomes coarse, and fine manual adjustment can be performed. It was difficult.

Since stainless steel, which is easy to bite due to its thermal expansion coefficient, is used as the material of the thermal displacement member, galling often occurs in the screw on the side of the thermal displacement member that is screwed into the die bolt. As a countermeasure against this, conventionally, a solution was attempted by using a special lubricant containing molybdenum disulfide or diamond powder, but sufficient results could not be obtained.

The present invention has been made in view of such a situation as described above, and performs fine manual adjustment with a simple structure and causes trouble due to galling of a screw portion between a thermal displacement member and a die bolt in a wide temperature range. It is an object of the present invention to provide a thermal displacement type T-die which can be prevented inside.

[0015]

The above objective is accomplished by a thermal displacement T-die as set forth in the appended claims. That is, (1) The plurality of thermal displacement units, each having a lip gap formed between the fixed lip and the flexible lip, provided in the width direction of the flexible lip of the T-die and having the die bolt inserted therein, heat-control the heat-displacement units respectively. A thermal displacement type T for adjusting the lip gap by transmitting thermal expansion or thermal contraction due to heating of the displacement unit to the flexible lip via a die bolt.
In the die, a protrusion is formed at a position facing the surface of the die main body to which the flexible lip is attached on the side opposite to the lip gap side, one end is locked to the protrusion, and the other end is protruded. A free end is located closer to the anti-flexible lip side, a screw is formed at the end of the free end, and a hole is formed through the axial center portion from the locked one end side to the free end side, and A plurality of thermal displacement units having heaters attached between the protrusions and the free ends and holes formed in the thermal displacement units are inserted, and one end side is fixed to the flexible lip by screwing or the like. A die bolt having a free end formed with a threaded portion, a threaded portion formed at the free end of the thermal displacement unit and a threaded portion formed at the other end of the die bolt are engaged by screwing. The above nuts have a pitch and heat Unit and screwed different from the thermal displacement type T-die and a pitch of the screw.

(2) A plurality of thermal displacement units, each having a lip gap formed between the fixed lip and the flexible lip, are provided in the width direction of the flexible lip of the T-die and the die bolts are inserted to control heating of the respective thermal displacement units. A thermal displacement T-die that adjusts the lip gap by transmitting thermal expansion or thermal contraction due to heating of the thermal displacement unit to the flexible lip via a die bolt, wherein the die main body to which the flexible lip is attached is A protrusion is formed at a position facing the surface of the flexible lip opposite to the lip gap, and one end is locked to the protrusion,
A hole through which the other end is located on the side opposite the flexible lip from the protrusion to form a free end, a screw is formed at the end of the free end, and the shaft center portion is penetrated from the locked one end to the free end. And a plurality of thermal displacement units having heaters attached between the protrusion and the free end and the holes formed in the thermal displacement unit are inserted, and one end is pressed against the flexible lip. , A die bolt having a free end formed with a threaded portion on the other end side, a threaded portion formed on the free end of the thermal displacement unit, and a threaded portion formed on the other end of the die bolt by screwing A thermal displacement T-die, which comprises nuts that engage with each other, wherein the nuts have different screw pitches for screwing with the die bolts and screw pitches for screwing with the thermal displacement unit.

(3) A plurality of thermal displacement units, each having a lip gap formed between the fixed lip and the flexible lip, which are provided in the width direction of the flexible lip of the T-die and have a die bolt inserted therein, heat-control each. A thermal displacement T-die that adjusts the lip gap by transmitting thermal expansion or thermal contraction due to heating of the thermal displacement unit to the flexible lip via a die bolt, wherein the die main body to which the flexible lip is attached is A protrusion is formed at a position facing the surface of the flexible lip opposite to the lip gap, and one end is locked to the protrusion,
The other end is located closer to the flexible lip than the protrusion to make it a free end, a screw is formed at the end of the free end, and a hole is formed through the shaft center from the locked one end to the free end. Insert a plurality of thermal displacement units that are provided with a heater between the protruding portion and the free end and through the holes provided in the thermal displacement unit, and screw one end side to the flexible lip. And a die bolt having a screw formed in a part located between the thermal displacement unit and the flexible lip, with the other end side being a free end.
The thermal displacement unit comprises a nut that engages a threaded portion formed on the free end of the heat displacement unit and a threaded portion formed on a part of the die bolt by screwing, and the nut has a pitch of the screw that engages with the die bolt. A thermal displacement type T-die with a different pitch of the screw screwed with the thermal displacement unit.

(4) A plurality of thermal displacement units, each having a lip gap formed between the fixed lip and the flexible lip, which are provided in the width direction of the flexible lip of the T-die and through which die bolts are inserted, are heated and controlled. A thermal displacement T-die that adjusts the lip gap by transmitting thermal expansion or thermal contraction due to heating of the thermal displacement unit to the flexible lip via a die bolt, wherein the die main body to which the flexible lip is attached is A protrusion is formed at a position facing the surface of the flexible lip opposite to the lip gap, and one end is locked to the protrusion,
The other end is located closer to the flexible lip than the protrusion to make it a free end, a screw is formed at the end of the free end, and a hole is formed through the shaft center from the locked one end to the free end. A plurality of thermal displacement units, which are provided with a heater between the protruding portion and the free end, are inserted through the holes formed in the thermal displacement unit, and one end is pressed against the flexible lip, A die bolt having the other end as a free end and a screw formed in a part located between the thermal displacement unit and the flexible lip, and a screw portion formed at the free end of the thermal displacement unit and the die bolt. It consists of a nut that engages with a partially formed screw part by screwing, and the nut is a thermal displacement type in which the pitch of the screw screwed with the die bolt and the pitch of the screw screwed with the thermal displacement unit are different. T-die.

(5) The screw portion of the thermal displacement unit that is engaged with the die bolt by the nut is made of a material having a coefficient of thermal expansion equivalent to that of the die bolt. Except for the screw portion, the coefficient of thermal expansion is the same as that of the die bolt or more than that of the die bolt. The thermal displacement T-die according to (1) or (2) or (3) or (4), which is made of a material having a large thermal expansion coefficient, and the two materials are metallurgically bonded.

(6) The material of the thermal displacement unit is stainless steel except for the screw part of the nut that engages with the die bolt
(5) The thermal displacement T-die described. Hereinafter, the operation and the like of the present invention will be described based on Examples.

[0021]

1 is a sectional view showing a first embodiment of a thermal displacement type T die (lip gap adjusting type thermal displacement type) according to the present invention, in which a die bolt is a flexible lip as the thermal displacement unit is heated. FIG. 8 is a view of a thermal differential type thermal displacement type T-die that acts in a direction of pulling up to widen a lip gap.

In FIG. 1, 1 is a die bolt, 2 is a thermal displacement unit, 3 is a nut, 4 is a heater, 5 is a flexible lip, 6 is a fixed lip, 7 is a lip gap, 8 is a hole, and 9 is a thermal displacement unit. A mounting flange (projection), 10 is a threaded portion between the die bolt and the nut, 11 is a threaded portion between the thermal displacement unit and the nut, and 12 and 13 are lock nuts. The thermal displacement unit 2 has an integrated structure up to the end of the threaded portion 11.

A flexible lip 5 formed on the tip of the die body.
A lip gap 7 is formed in a portion where the fixed lip 6 and the fixed lip 6 face each other. A flange (hereinafter, also referred to as a protrusion) 9 for mounting the thermal displacement unit 2 is formed on the side of the flexible lip 5 opposite to the lip gap 7 of the die body.

One end side of a plurality of thermal displacement units 2 provided in the width direction of the flexible lip 5 is attached to the side of the protrusion 9 opposite to the flexible lip 5.

The thermal displacement unit 2 has a hole 8 through which a die bolt is inserted, which is formed at the center of the shaft. A screw portion is formed at one end of the thermal displacement unit 2. The other end located on the flexible lip 5 side is formed with a free end having a threaded portion that can be threadedly engaged with the nut 3. Further, the heater 4 is disposed outside the portion of the thermal displacement unit 2 that is located on the side opposite to the flexible lip 5 with respect to the protrusion 9, and a thermocouple (not shown) is inserted inside.

First, the thermal displacement unit 2 is attached to the protrusion 9 by screwing and fixed by the lock nut 12. The die bolt 1 is inserted into the through hole 8 of the thermal displacement unit 2, and the lower end of the die bolt 1 is screwed onto the flexible lip 5 and fixed by the lock nut 13.

Next, the die bolt 1 and the thermal displacement unit 2
The nuts 3 to be screwed into the respective parts are screwed on from above. Since the screws of the die bolt 1 and the thermal displacement unit 2 that are screwed into the nut 3 are formed as so-called differential screws having the same screw direction but different screw pitches, when the nut 3 is screwed in. The relative position in the axial direction between the die bolt 1 and the thermal displacement unit 2 changes.

That is, in FIG. 1, when the screw pitch of the die bolt 1 and the screw pitch of the thermal displacement unit 2 are the same, the relative position between the die bolt 1 and the thermal displacement unit 2 does not change when the nut 3 is screwed in. However, if the pitch of the screw of the die bolt 1 is slightly larger than the pitch of the screw of the thermal displacement unit 2, the relative position of the die bolt 1 to the thermal displacement unit 2 is slightly upward as the nut 3 is screwed in. The die bolt 1 is moved to the thermal displacement unit 2 by rotating the nut 3 in the opposite direction.
The position relative to and is moved slightly downward.

The thermal displacement unit 2 is made of a material having the same coefficient of thermal expansion as the die bolt 1 or a material larger than that of the die bolt 1, and the screwing portion of the thermal displacement unit 2 which is screwed with the nut 3 has the same thermal expansion coefficient as the die bolt 1. The thermal displacement unit 2 is formed of a material having a coefficient, and the main body portion of the thermal displacement unit 2 and the screw portion screwed with the nut 3 are metallurgically joined by friction welding or the like.

In such a structure, first, the nut 3 is manually rotated to adjust the position of the flexible lip 5 to maintain the lip gap 7 at a predetermined value. Next, the thermal displacement unit 2 is heated by the heater 4, so that the thermal displacement unit 2 extends to the free end side (upward), and the die bolt 1 connected by the nut 3 accordingly is separated from the thermal displacement unit 2 and the die bolt 1. Even if the thermal expansion coefficients are the same, the thermal displacement unit 2 is closer to the heater 4 which is the heating source, and therefore the expansion amount is larger than the die bolt 1. Therefore, the flexible lip 5 is reliably pulled up to widen the lip gap 7, and Along with this, the flow rate of the molten resin increases.

At this time, the heat from the heater 4 is transferred to the flexible lip 5 through the die bolt 1 and transferred to the flowing molten resin to reduce the viscosity of the molten resin, so that the flow rate of the molten resin is further increased. .

When the power supply to the heater 4 is cut off, the thermal displacement unit 2 contracts, and the die bolt 1 attached thereto descends to push down the flexible lip 5 and narrow the lip gap 7 to narrow the flow rate of the molten resin. In addition to decreasing the temperature of the flexible lip 5,
The viscosity of the molten resin flowing through the tank increases and acts to further strengthen the decrease in the flow rate of the molten resin.

In the present invention, since the differential screw is adopted for the nut 3 for fixing the die bolt 1 and the thermal displacement unit 2 to each other, the axial force due to the expansion difference between the thermal displacement unit 2 and the die bolt 1 is thermally displaced. Unit 2 → Nut 3 (manual adjustment differential screw) → Die bolt 1 is transmitted and dispersed, and plastic deformation occurs due to thermal expansion or lowering of the yield point of the material at high temperature, and it is thought that these factors overlap and induce. It effectively acts against the galling and the seizure phenomenon which are already known.

The thermal displacement unit 2 is axially divided into two parts according to the intended use, and the divided members are metallurgically bonded to each other, so that it is possible to cope with extruded molten resin that requires high temperature. The austenitic stainless steel with a high linear expansion coefficient of 17 × 10 ^-6 / ° C, whose length is remarkably changed depending on the original temperature, is used as the two materials, and the thermal displacement unit 2 is used as the main body. And the threaded portion are divided into two parts, and the threaded portion has a high linear expansion coefficient and a high yield point stress at a high temperature by selecting and using a material having a high yield point stress at a high temperature for the threaded portion. Initial goals can be achieved without the need to employ or develop special materials.

FIG. 2 is a diagram showing a second embodiment according to the present invention, and the reference numerals of the respective parts are the same as those in FIG. In the first embodiment, when the thermal displacement unit 2 is heated by the heater 4, the thermal displacement unit 2 extends toward the free end side, and the die bolt 1 attached to the thermal displacement unit 2 acts in the direction of pulling up the flexible lip 5 to cause the lip to move. In contrast to the thermal differential type in which the gap 7 is widened, in the second embodiment, the thermal displacement unit 2 fixed to the projecting portion 9 when the thermal displacement unit 2 is heated by the heater 4 is the projecting portion. 9 extends to the free end side located on the flexible lip 5 side, and accordingly, the die bolt 1 engaged with the thermal displacement unit 2 by the nut 3 acts in the direction of pushing down the flexible lip 5 and narrows the lip gap 7. It shows the case of the thermal direct acting type that acts in the direction.

In FIG. 2, the thermal displacement unit 2 is fixed to the protrusion 9 and the die bolt 1 is inserted into the hole 8 of the thermal displacement unit 2 by the same procedure as in the case of the first embodiment.
After inserting the nut (manual adjustment differential screw) 3 into the die bolt 1 in advance, the lower end of the die bolt 1 is fixed to the flexible lip 5 by the lock nut 13.

The nut 3 is rotated to adjust the position of the flexible lip 5 to maintain the lip gap 7 at a predetermined value. Then, the thermal displacement unit 2 is heated by the heater 4 so that the thermal displacement unit 2 extends toward the free end side (downward), and accordingly, the die bolt 1 engaged by the nut 3 pushes down the flexible lip 5 downwards. The gap 7 is narrowed, thereby reducing the flow rate of the molten resin.

In this case, the heat from the heater 4 is transferred to the flexible lip 5 via the die bolt 1 to raise the temperature of the molten resin flowing in the lip gap 7 to reduce its viscosity, thereby reducing the flow rate. Although it acts in the direction of weakening, it eliminates the roughness of precision during manual adjustment due to the rough pitch of the screw in the conventional direct acting screw type, and uses the differential screw to manually adjust the position of the flexible lip. It is extremely effective in terms of adjustment and further making it possible to perform ultrafine adjustment by the heater.

FIG. 3 is a diagram showing a third embodiment and FIG. 4 is a diagram showing a fourth embodiment. In each of the first and second embodiments, the die bolt 1 and the flexible lip 5 are provided. 2 is a structure in which the tip of the die bolt 1 is simply pressed against the flexible lip 5, whereas FIG. 3 is an application example to FIG. 1 and FIG. Two
It is an application example for.

Also in this structure, the differential nut that engages the die bolt and the thermal displacement unit is rotated in advance to set the lip gap to a predetermined value, and then the thermal displacement unit is heated by the heater. It is possible to make a fine adjustment of the lip gap.

[0041]

As described above, according to the present invention, the following effects are obtained as described in the above embodiment. (1) Conventionally, since the adjusting screw by manual operation is a direct-acting type, the accuracy is rough and it is only an auxiliary operation, but the invention of the present application enables adjustment with extremely high accuracy,
With the heater, it is possible to make further fine adjustments. (2) The thermal displacement unit is divided into a material such as stainless steel with a large coefficient of thermal expansion and a non-stainless material such as carbon steel for machine structure that can be hardened, and a nut that engages the die bolt with the non-stainless material. By forming screws to be screwed together and metallurgically joining the two materials, it is possible to prevent galling and seizure of the manual adjustment screw of the automatic die. (3) The manually adjustable differential screw (nut) according to the present invention has an extremely simple structure and is simply screwed into the thermal displacement unit and the die bolt so as to rotate freely. It can be operated and adjusted in the atmosphere, and can be assembled and removed at room temperature very easily.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view of a thermal displacement T-die showing a first embodiment according to the present invention.

FIG. 2 is a partial cross-sectional view of a thermal displacement T-die showing a second embodiment according to the present invention.

FIG. 3 is a partial sectional view of a thermal displacement T-die showing a third embodiment according to the present invention.

FIG. 4 is a partial sectional view of a thermal displacement T-die showing a fourth embodiment according to the present invention.

FIG. 5 is a cross-sectional view of a thermal displacement T-die in a first example of the prior art.

FIG. 6 is a cross-sectional view of a thermal displacement T-die in a second prior art example.

[Explanation of symbols]

 1 Die Bolt 2 Thermal Displacement Unit 3 Nut 4 Heater 5 Flexible Lip 6 Fixed Lip 7 Lip Gap 8 Hole 9 Protrusions 10, 11 Screwing Part 12, 13 Lock Nut 101 Thermal Displacement Unit 102 Heater 103 Die Bolt 104 Flexible Lip 105 Lip Gap 201 Die bolt 202 Hole 203, 206 Side hole 204 Air supply pipe 205 Thermal displacement unit 207 Heater 208 Flexible lip 209 Lip gap

Claims (6)

[Claims] 1. A thermal displacement unit having a lip gap formed between a fixed lip and a flexible lip, wherein a plurality of thermal displacement units are provided in the width direction of the flexible lip of the T-die and through which die bolts are inserted, and the thermal displacement units are heated and controlled. A thermal displacement T-die that adjusts the lip gap by transmitting thermal expansion or thermal contraction due to heating of a thermal displacement unit to a flexible lip via a die bolt, wherein the die main body to which the flexible lip is mounted is adjustable. A protrusion is formed at a position facing the surface of the flexible lip on the side opposite to the lip gap, one end is locked to the protrusion, and the other end is positioned on the side opposite the flexible lip from the protrusion to form a free end. A screw is formed at the end of the free end, a hole penetrating the shaft center portion from the locked one end side to the free end side is bored, and a heater is attached between the protrusion and the free end. A plurality of thermal displacement units, A die bolt which is a free end in which a hole formed in the thermal displacement unit is inserted, one end side of which is fixed to the flexible lip by screwing or the like, and a screw portion is formed on the other end side of the die bolt, A nut that engages a threaded portion formed at the free end and a threaded portion formed at the other end of the die bolt by screwing, wherein the nut is a pitch of the screw that is engaged with the die bolt and a thermal displacement unit. A thermal displacement type T-die characterized in that the pitch of screws to be screwed is different. 2. A thermal displacement unit having a lip gap formed between a fixed lip and a flexible lip, wherein a plurality of thermal displacement units each having a die bolt inserted therein are provided in the width direction of the flexible lip of the T die, and the heat displacement units are heat-controlled. A thermal displacement T-die that adjusts the lip gap by transmitting thermal expansion or thermal contraction due to heating of a thermal displacement unit to a flexible lip via a die bolt, wherein the die main body to which the flexible lip is mounted is adjustable. A protrusion is formed at a position facing the surface of the flexible lip on the side opposite to the lip gap, one end is locked to the protrusion, and the other end is positioned on the side opposite the flexible lip from the protrusion to form a free end. A screw is formed at the end of the free end, a hole penetrating the shaft center portion from the locked one end side to the free end side is bored, and a heater is attached between the protrusion and the free end. A plurality of thermal displacement units, A die bolt that is a free end having a free end formed by inserting a hole formed in the thermal displacement unit, pressing one end side against the flexible lip, and forming a threaded portion on the other end side, and a free end part of the thermal displacement unit. A nut that engages the formed screw portion and the screw portion formed at the other end of the die bolt by screwing, and the nut is a screw thread that engages with the die bolt and a screw that engages with the thermal displacement unit. The thermal displacement type T-die, which has a different pitch. 3. Thermally displacing units, each of which is provided in the width direction of the flexible lip of the T die and has a lip gap formed between the fixed lip and the flexible lip, and through which a die bolt is inserted, are controlled by heating. A thermal displacement T-die that adjusts the lip gap by transmitting thermal expansion or thermal contraction due to heating of a thermal displacement unit to a flexible lip via a die bolt, wherein the die main body to which the flexible lip is mounted is adjustable. A protrusion is formed at a position facing the surface of the flexible lip opposite to the lip gap, one end is locked to the protrusion, and the other end is positioned closer to the flexible lip than the protrusion to form a free end. A plurality of screws with a screw formed at the end of the free end, a hole penetrating the shaft center from the locked one end to the free end, and a heater installed between the protrusion and the free end. With thermal displacement unit of the The thermal displacement unit is inserted through a hole, one end side is fixed to the flexible lip by screwing or the like, and the other end side is a free end, which is located between the thermal displacement unit and the flexible lip. A nut that engages a threaded portion formed on a free end portion of the thermal displacement unit and a threaded portion formed on a part of the die bolt by screw engagement, Is a thermal displacement type T-die characterized in that the pitch of the screw screwed with the die bolt is different from the pitch of the screw screwed with the thermal displacement unit. 4. A thermal displacement unit having a lip gap formed between a fixed lip and a flexible lip, wherein a plurality of thermal displacement units each having a die bolt inserted therein are provided in a width direction of the flexible lip of the T-die, and each of the thermal displacement units is heat-controlled. A thermal displacement T-die that adjusts the lip gap by transmitting thermal expansion or thermal contraction due to heating of a thermal displacement unit to a flexible lip via a die bolt, wherein the die main body to which the flexible lip is mounted is adjustable. A protrusion is formed at a position facing the surface of the flexible lip opposite to the lip gap, one end is locked to the protrusion, and the other end is positioned closer to the flexible lip than the protrusion to form a free end. A plurality of screws with a screw formed at the end of the free end, a hole penetrating the shaft center from the locked one end to the free end, and a heater installed between the protrusion and the free end. With thermal displacement unit of the The thermal displacement unit is inserted through the hole, one end side is pressed against the flexible lip, the other end side is a free end, and a screw is placed on a part located between the thermal displacement unit and the flexible lip. The die bolt includes a nut that engages the threaded portion formed on the free end portion of the thermal displacement unit and the threaded portion formed on a part of the die bolt by screwing, and the nut is the die bolt and the screw. A thermal displacement type T-die, characterized in that the pitch of the screw to be fitted is different from the pitch of the screw to be screwed to the thermal displacement unit. 5. The screw portion of the thermal displacement unit that is engaged with the die bolt by the nut is made of a material having a coefficient of thermal expansion equivalent to that of the die bolt. The thermal displacement T-die according to claim 1, 2 or 3 or 4, which is made of a material having a large expansion coefficient, and the two materials are metallurgically bonded. 6. The thermal displacement type T die according to claim 5, wherein the material of the thermal displacement unit is stainless steel except for the threaded portion with the nut that engages with the die bolt.