JP2002178385A - Lip gap setter of thermally displacing type t-die - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lip gap setter of a thermally displacing type T-die capable of dealing with a positive error and a negative error of a thickness of a sheet or the like, with proper balance at a lip gap regulating time without operating an unbalanced force at a thermally displacing member at the same time as pushing or pulling the member by a push-bolt and a pull-bolt. SOLUTION: The lip gap setter of the thermally displacing type T-die comprises the thermally displacing member for pushing or pulling a flexible lip by a thermal displacement to regulate a lip gap, and a preset bolt coupled to the member. The bolt has the push-bolt and the pull-bolt. The lip gap setter pushes the member by the push-bolt and simultaneously pulls the member by the pull-bolt to preset the member. The push-bolt or the pull-bolt is arranged at a central axis of the member. The pull-bolt or the push-bolt is symmetrically disposed at both sides of the push-bolt or the pull-bolt with the central axis of the member as a symmetrical axis.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lip gap setting device of a thermal displacement type T die used for molding a sheet or a film of a thermoplastic resin (hereinafter referred to as "sheet etc.").

[0002]

2. Description of the Related Art An extruder, a T-die,
It consists of a forming roll, a take-up / winding machine, etc. The raw material melted and kneaded by the extruder is supplied to the T-die, the molten resin is discharged from the slit-shaped lip gap of the T-die, and cooled by the forming roll. Under such an operation, the sheet is formed into a sheet or the like.

[0003] The slit gap distribution of the T die can be adjusted manually or automatically by a number of die bolts attached to the flexible lip. The lip gap adjusting device of the automatic T-die includes a servo motor type, a pneumatic type, a thermal displacement type and the like, and a thermal displacement type is often used.

The thermal displacement type lip gap adjusting device is composed of a thermal displacement member and a heating / cooling means, and adjusts the lip gap by pushing and pulling a flexible lip by expansion and contraction of the thermal displacement member. Although such a thermal displacement lip gap adjusting device has a narrow adjustment range, it has advantages such as high reliability because there is no mechanical moving part, precise and simultaneous operation, compactness and low cost.

As a conventional lip gap adjusting device, there has been one shown in FIGS.

As shown in FIGS. 6 and 7, the initial lip gap adjusting device was a single operation type in which the tip of a bolt 101 with a heater 100 was brought into contact with the flexible lip 102 and the flexible lip 102 was pushed. (For example, US Pat. No. 3,940,221). That is, the power is supplied to the heater 100 to heat and expand the bolt 101, and the flexible lip 102 is pushed to make the flexible lip 1
02 in the closing direction.
By contracting the flexible lip 102
The elastic lip 102 and the pressure of the molten resin move the flexible lip 102 in the opening direction. However, since the elastic restoring force of the flexible lip 102 and the pressure of the molten resin are usually small, when the flexible lip 102 is to be opened, the tip of the bolt 101 rises from the flexible lip 102, and the automatic operation characteristic diagram of FIG. As described above, there is a problem that control of the flexible lip 102 becomes impossible.

The device shown in FIG. 8A is of a simple dual operation type capable of positively pulling back the flexible lip 202 and capable of push-pull control.
1 is screwed to the upper part of the flexible lip 202, and the base end of the bolt 201 is
4 and is fixed. This device has the advantage that the flexible lip 202 can be dual-operated manually, but in the case of automatic operation, there remains a problem that is not much different from the single operation type. In this device, the amount of thermal displacement of the bolt 201 is limited, and the play in the axial direction of the bolt 201 (the axial gap of the head and the backlash of the bolt) is large. For example, while a bolt having an effective length of 150 mm (linear expansion coefficient: 1.1 × 10 ⁻⁵ ) has a thermal displacement of about 500 μm in a temperature range of 300 ° C., the backlash of the bolt is, for example, M12 × 1.25. (Intermediate JIS standard) The average is 115 μm, and the gap between the bolt heads cannot be so small, so the axial play of the bolt is 150 to 200 μm.
Reach As a result, the automatic operation characteristic becomes extremely nonlinear, and the control result is not improved. Therefore, when the operation direction changes from pushing to pulling, the tip of the screw portion of the bolt 201 is in a floating state (the floating amount is 150 to 2 in the above example).
00 μm), as shown in the automatic operation characteristic diagram of FIG. 8B, there is a problem that control of the flexible lip 202 becomes impossible.

The device shown in FIG. 9A is a device in which the axial play of the bolt 301 with the heater 300 is absorbed by the disc spring 302. As shown in the automatic operation characteristic diagram of FIG. There is a problem that precise thickness profile (thickness distribution) control is difficult because the automatic operation characteristics are nonlinear.

[0009] The apparatus shown in FIG.
By fixing the attached bolt 401 to the die main body 403 with two lock nuts 402, as shown in the automatic operation characteristic diagram of FIG. 10B, the transition from the push to the pull can be performed relatively smoothly. However, there is a problem that the rigidity on the pull side is slightly smaller than the rigidity on the push side, and it is difficult to operate the lock nut 402 on the back side.

Therefore, as shown in FIG. 11, a heat displacement type lip gap setting device in which the heat block 500 and the preset bolt 501 are separated and the bolt 501 is constituted by a push bolt 502 and a pull bolt 503 is proposed. (Japanese Patent Publication No. 6-37073). This device eliminates the control failure of the flexible lip 504 due to the play of the bolt 501 by simultaneously pushing and pulling the heat block 500 by the push bolt 502 and the pull bolt 503.

However, since the pull bolt 503 is positioned eccentrically from the axis of the heat block 500, when the operation direction changes from pushing to pulling, the flexible lip 5
04 generates a force to pull the heat block 500. This force is applied to the pressing / tensile member 506 shown in FIG.
The unbalanced force acts on the heat block 500 by being transmitted from the head of the draw bolt 503 to the die body 509 via the heat block 500, the rotating body 507, and the leg 508.
On the tension side, a pull bolt 503, a leg 508, a rotating body 5
07, the heat block 500, and the pressing / pulling member 506 are connected in series, so that the rigidity on the pulling side is significantly lower than that on the pressing side, and the adjustment of the lip gap 505 is hindered. there were.

[0012]

SUMMARY OF THE INVENTION In the present invention, an unbalanced force is not applied to the thermal displacement member when the thermal displacement member is simultaneously pushed and pulled by the push bolt and the pull bolt. The present invention provides a lip gap setting device for a thermal displacement T-die capable of coping with a plus error and a minus error of the thickness in a good balance.

[0013]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a thermal displacement member for adjusting a lip gap by pushing and pulling a flexible lip by thermal displacement, and a preset member connected to the thermal displacement member. In a lip gap setting device for a thermal displacement T-die provided with a bolt, the bolt is:
A push bolt and a pull bolt are provided, and the heat displacement member is pressed by the push bolt and is simultaneously pulled and pulled by the pull bolt to perform presetting, and the push bolt or the pull bolt is placed on a central axis of the heat displacement member. Wherein said pull bolt or said push bolt is symmetrically disposed on both sides of said push bolt or said pull bolt with the central axis of said thermal displacement member being a symmetric axis. Provided is a device for setting a lip gap of a T-die.

It is preferable that the push bolt and the pull bolt are set to have substantially the same total effective area and spring constant.

Preferably, the heat displacement member is a heat rod (an example of a heat displacement member).

Further, an outer flange is formed at a base end of the heat rod, screw holes are provided on both sides of a connecting member having a locking hole in the center, and the locking hole is inserted through the heat rod to form the connecting member. Is fixed to the outer flange of the heat rod, the push bolt is disposed on the central axis of the heat rod, and the symmetrically disposed pull bolt is screwed into the screw hole of the connecting member. Is preferred.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. (First Embodiment) As shown in FIG. 1, a T-die 1 includes two main bodies 2 and 3, a fixing lip 4 is formed at a tip of one main body 2, and a fixing lip 4 is formed at a tip of the other main body 3. A flexible lip 5 is formed, and a wide slit-like lip gap 6 is formed between the lips 4 and 5.

The lip gap setting device of the thermal displacement type T die is as follows.
A thermal displacement unit 7 and a preset bolt 8 are provided. The thermal displacement unit 7 adjusts the lip gap 6 by expanding and contracting the heat rod 9 by air cooling and heater heating. Male screw 9a at the end of heat rod 9
The male screw 9a is screwed into a screw hole 5a provided in the flexible lip 5, and the nut 5b is used to prevent loosening, so that the tip of the heat rod 9 is screwed to the flexible lip 5. Further, the base end of the heat rod 9 is fixed to the main body 3 via a bolt portion 8.

A passage hole 9b for air (cooling medium) is formed in the heat rod 9, and a heater wire 9c is wound around the outer periphery of the heat rod 9. Then, air is circulated through the passage hole 9b to cool the heat rod 9, whereby the heat rod 9 contracts in the axial direction and moves the flexible lip 5 in the opening direction, while power is supplied to the heater 9c to heat the heat rod 9. This causes the heat rod 9 to extend and move the flexible lip 5 in the closing direction.

The bolt portion 8 includes a push bolt 10 and a pull bolt 11 formed of the same material.
Is attached to the bolt fixing portion 12, and the bolt fixing portion 12
Are fixed to the main body 3 with fixing bolts 13.

As shown in FIG. 4, a screw hole 12a is provided in the center of the bolt fixing portion 12, and a through hole 12b having a smooth inner peripheral surface is formed on both sides, and a push hole 12a is formed in the screw hole 12a. A bolt 10 is screwed into the through hole 12b, and a pull bolt 11
Is inserted.

An outer collar 9 d is provided at the base end of the heat rod 9.
A locking groove 9e is provided at the center of the base end surface of the heat rod 9. Reference numeral 14 in the figure is a connecting member, and a locking hole 14a is provided at the center, and screw holes 14b are provided at both sides. Each is provided. The heat rod 9 is inserted into the locking hole 14 a of the connecting member 14, and the outer flange 9 of the heat rod 9 is
d is locked, the screw portion 11a of the pull bolt 11 is screwed into the screw hole 14b, and the tip of the push bolt 10 is fitted into the locking groove 9e of the heat rod 9.

Then, as shown in FIG.
Are arranged coaxially with the heat rod 9, and a pull bolt 11 is provided at a symmetrical position with respect to the push bolt 10 as a symmetric axis.

The push bolt 10 is formed with an air hole 10a communicating with the air passage 9b, so that the push bolt 10 that is in direct contact with the heat rod 9 is air-cooled.

The thermal displacement unit 7 thus configured
As shown in FIG. 2, a plurality of are arranged in the width direction of the flexible lip 5.

Next, the preset operation by the bolt 8 will be described.

First, the tip of the push bolt 10 is brought into contact with the base end of the heat rod 9 and the bolt head 1 of the pull bolt 11 is moved.
1b is brought into contact with the bolt fixing portion 12, and the push bolt 1
The heat rod 9 is set in a state where no compression force and no tension force is generated by the 0 and the pull bolt 11 (reference state).

Next, as shown in FIG. 4, the push bolt 10 is manually screwed by δo to apply a preset load Qo to both bolts 10 and 11. At this time, the effective length of the push bolt 10 contracts by λ _1, and the effective length of the pull bolt 11 extends by λ ₂ . At the time of presetting, the operating temperature of the heat rod 9 is set to an intermediate value of the operating temperature range. For example, the operating temperature range is 100 to 400 ° C.
Is set to 250 ° C. Sign L ₁ in FIG. 4 shows the effective length of the push bolts 10, L ₂ represents the effective length of pull bolt 11.

After the completion of the preset, the lip gap 6 is automatically adjusted by the thermal displacement unit 7. That is, when a thickness deviation occurs in a sheet or the like, the heat rod 9 of the thermal displacement unit 7 corresponding to the thick portion is expanded in the above-described manner, and the flexible lip 5 is pushed to eliminate the deviation. At this time, as shown in the load displacement diagram of FIG.
At the same time as the flexible lip 5 is pushed, a compressive force Pc acts on the bolt portion 8 as a reaction, and the push bolt 10 is λ ₁
At the same time, the elongation of the pull bolt 11 is reduced to be smaller than λ ₂ . The effective spring constant of the bolt portion 8 with respect to the external force Pc is C ₁ + C ₂ . When the heat rod 9 is further expanded, Pc further increases, the extension amount of the pull bolt 11 becomes zero, and Pcmax acts on the push bolt 10. on the other hand,
In a thin part such as a sheet, the heat rod 9 of the thermal displacement unit 7 corresponding to the part is contracted in the above-described manner, and the flexible lip 5 is pulled back to eliminate the deviation. At this time, as shown in the load displacement diagram, at the same time as the flexible lip 5 is pulled, a pulling force Pt acts on the bolt portion 8 as a reaction to the pulling, and the pull bolt 11 further extends beyond λ ₂ and at the same time, the push bolt 10 the amount of shrinkage is reduced than λ _1. The effective spring constant in this case is also C ₁ + C ₂ . When the heat rod 9 is further contracted, Pt further increases, the amount of extension of the push bolt 10 becomes zero, and Pt is applied to the pull bolt 11.
max works.

The thickness profile of the T-die 1 is controlled by a scanning thickness gauge (not shown) and a computer. That is, the heat rod 9 of the thermal displacement unit 7 corresponding to a thick portion in a thickness profile of a sheet or the like measured by the scanning thickness gauge is heated and expanded by a command from the computer, and a thermal displacement corresponding to a thin portion is obtained. The heat rod 9 of the unit 7 is cooled and contracted in accordance with a command from the computer.

In FIG. 1, reference numeral 15 denotes a heat insulating plate provided between the main body 3 and the heat rod 9, and 16 denotes a die cover. Since the bolt heads of the push bolt 10 and the pull bolt 11 are located on the upper surface side of the T-die 1, the operation and inspection can be performed without removing the die cover 16 one by one, thereby facilitating maintenance. (Second Embodiment) As shown in FIG. 5, a lip gap setting device for a thermal displacement T-die according to the present embodiment uses an effective cross-sectional area of a push bolt 10 and a pull bolt 11 of the same material (the pull bolt 11).
In this case, the total length of the cross-sectional areas of the two pull bolts 11) and the effective lengths L ₁ and L ₂ are made substantially the same, so that both bolts 10 and
11, the spring constants C ₁ and C ₂ are substantially the same (the compression spring constant of the push bolt and the tension spring constant of the pull bolt are substantially the same), and the compression displacement of the push bolt 10 and the tensile displacement of the pull bolt 11 are preset. Are set to be approximately the same.

The effective lengths L ₁ and L ₂ are adjusted by providing a hole 15 for accommodating the bolt head 11b of the pull bolt 11. The design of the depth of the hole 15, the position where the hole 15 is provided, and the like are appropriately changed.

In the first embodiment, both bolts 10, 11
Unlike larger effective length L _1, L ₂ of, thus the spring constant C _1, C ₂ are different, as shown in FIG. 4, the time preset completion λ ₁ <λ ₂ becomes, at the lip gap adjustment by thermal displacement unit 7 Pcmax> Ptmax (in the drawing, Pcma
x is about three times Ptmax). However, as in the second embodiment, the sectional areas and the effective lengths L ₁ ,
L ₂ is set to be substantially the same, so that the spring constants C ₁ , C ₂
Are set to be substantially the same, as shown in FIG. 5, λ ₁ ≒ λ ₂ in the preset state, and Pcmax ≒ Ptmax ≒ 2 when the lip gap is adjusted by the thermal displacement unit 7.
It becomes Qo. As a result, in the second embodiment, in the operation of pushing and pulling the flexible lip 5, the amount of movement and the amount of pulling by pushing the flexible lip 5 under the condition that the compressive force acts on the push bolt 10 and the tensile force acts on the draw bolt 11 simultaneously. And the amount of movement of the sheet or the like can be made equal, and a positive error and a negative error of the thickness of the sheet or the like can be well-balanced.

The same components of the second embodiment as those of the first embodiment are given the same reference numerals as those used in the first embodiment in FIG. 5, and the description thereof will be omitted.

The pull bolt 11 may be provided on the center axis of the heat rod 9, and the push bolt 10 may be provided on both sides of the pull bolt 11. Pcmax and Ptmax are determined in consideration of the allowable loads of the bolts 10 and 11.

The term "lip gap adjustment" in the text refers to the adjustment of the thickness profile of a sheet or the like, and the term "lip gap setting" refers to the setting of the average value of the lip gap. In molding a sheet or the like, the average value of the lip gap is adjusted or set according to the thickness of the sheet or the like.

[0037]

According to the lip gap setting device of the thermal displacement T-die of the present invention, the pull bolt or the push bolt is symmetrically disposed on both sides of the push bolt or the pull bolt disposed coaxially with the heat rod. Therefore, unbalanced force does not act on the heat rod at the time of preset.

Further, since the total effective area and the spring constant of each of the push bolt and the pull bolt are set to be substantially the same, the maximum load when pressing the heat rod and the maximum load when pulling the heat rod are set. And the amount of movement of the flexible lip pushing and pulling under the conditions where both the pressing of the push bolt and the pulling of the pull bolt act together when adjusting the lip gap can be made almost the same, and the plus error of the thickness of the sheet etc. And negative errors in a well-balanced manner.

Further, since the pull bolt is connected to the heat rod via only the connecting member, the rigidity of the pull side composed of the pull bolt, the connecting member and the heat rod can be sufficiently increased, and the force and the force can be increased. Incorrect adjustment of the lip gap due to rigidity imbalance can be prevented.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing a lip gap setting device of a thermal displacement T-die according to a first embodiment of the present invention.

FIG. 2 is a view taken in the direction of arrow A in FIG. 1;

FIG. 3 is a view taken in the direction of arrow B in FIG. 1;

FIG. 4A is a side sectional view of a preset bolt according to the first embodiment of the present invention, and FIG. 4B is a load displacement diagram.

FIG. 5A is a sectional side view of a preset bolt according to a second embodiment of the present invention, and FIG. 5B is a load displacement diagram.

FIG. 6 is a side sectional view of a conventional lip gap adjusting device of a thermal displacement T-die.

7A is a schematic side sectional view of a conventional lip gap adjusting device for a thermal displacement T-die, and FIG. 7B is a characteristic diagram.

FIG. 8A is a schematic side sectional view of a conventional lip gap adjusting device for a thermal displacement T-die, and FIG. 8B is a characteristic diagram.

9A is a schematic side sectional view of a conventional lip gap adjusting device for a thermal displacement T-die, and FIG. 9B is a characteristic diagram.

10A is a schematic side sectional view of a conventional lip gap adjusting device for a thermal displacement T-die, and FIG. 10B is a characteristic diagram.

FIG. 11 is a side sectional view of a conventional lip gap setting device for a thermal displacement T-die.

[Explanation of symbols]

 Reference Signs List 1 T die 2 Main body 3 Main body 4 Fixed lip 5 Flexible lip 6 Lip gap 7 Thermal displacement unit 8 Preset bolt section 9 Heat rod (thermal displacement member) 9d Outer flange of heat rod 10 Push bolt 11 Pull bolt 14 Connection member 14a Connection Locking hole of member 14b Screw hole of connecting member

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4F207 AG01 AR07 AR12 KA01 KA17 KL76 KL84

Claims (4)

[Claims] 1. A lip gap setting device for a thermal displacement T-die, comprising: a thermal displacement member for adjusting a lip gap by pushing and pulling a flexible lip by thermal displacement; and a preset bolt connected to the thermal displacement member. In the above, the bolt is provided with a push bolt and a pull bolt, and is configured to press the thermal displacement member with the push bolt and at the same time pull by the pull bolt to perform presetting; It is arranged on the center axis of the displacement member, and on both sides of the push bolt or the draw bolt, the draw bolt or the push bolt is symmetrically arranged with the center axis of the thermal displacement member as a symmetric axis. Characteristic lip gap setting device for thermal displacement T-die. 2. The lip gap of the thermal displacement T-die according to claim 1, wherein the total effective area and the spring constant of each of the push bolt and the pull bolt are set to be substantially the same. Setting device. 3. The apparatus according to claim 1, wherein the heat displacement member is a heat rod. 4. An outer collar is formed at a base end of the heat rod, screw holes are provided on both sides of a connecting member having a locking hole in the center, and the locking hole is inserted through the heat rod to form the connecting member. Is fixed to the outer flange of the heat rod, the push bolt is disposed on the central axis of the heat rod, and the symmetrically disposed pull bolt is screwed into the screw hole of the connecting member. 4. The thermal displacement type T according to claim 3, wherein
Die lip gap setting device.