JPH0247335B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [1] Technical Field The present invention relates to a device for steplessly changing the circumferential speed of a roll in a longitudinal stretching machine for plastic film.

[2] Prior art A longitudinal stretching machine for plastic film is a machine that uses multiple rolls to perform preheating, stretching, and heat setting to remove internal strain and stabilize the shape of the product. To stretch the film longitudinally, the film is preheated on the surface of a plurality of heated preheating rolls, and the circumferential speed of the heatsetting roll is increased between the preheating roll and the heatsetting roll, and the film is stretched longitudinally in the film running direction. During stretching, the film is sequentially elongated on these preheated rolls due to thermal expansion and tension in a softened state, and gradually becomes slack on the rolls. In order to prevent this slack, reduce slippage on the rolls, and provide stable stretching, each preheating roll is set at a predetermined speed minus (deceleration) from the peripheral speed of the next roll (roll in the direction of film flow). . For this reason, conventionally, the drive system for each roll was created by calculating the circumferential speed ratio of the rolls in advance depending on the material of the film to be processed at the design stage, and the circumferential speed of the rolls was kept constant. Therefore, if the operating conditions or film material changed, the desired roll circumferential speed ratio was obtained by changing the pulley diameter of the belt drive pulley provided at the final stage of the drive system for each roll. Changes were made through trial and error based on experience and intuition, resulting in a lot of wasted effort and money, and in the case of films made from new materials that will appear in the future, even more effort and money will be required. .

[3] Purpose of the Invention The present invention eliminates the above-mentioned drawbacks, and allows changes to be made in a shorter time and more easily when the roll circumferential speed needs to be changed due to changes in the drawing ratio and operating conditions due to new materials in the future. Moreover, it is an object of the present invention to provide a continuously variable roll circumferential speed transmission device for a longitudinal stretching machine that enables highly accurate speed change.

[4] Summary of the Invention In a longitudinal stretching machine for plastic film, based on a roll that serves as a circumferential speed reference before or after the roll to be driven, the distance between the roll to be driven and the roll that serves as the circumferential speed reference is determined. In the installed power transmission drive system, two cylinders for input and output, each having spline-shaped teeth with different numbers of teeth on the inner periphery of the cylinders, are arranged side by side on the same axis, and the An elastic ring having teeth on the outer periphery having the same pitch as the teeth of the cylinder and the same number of teeth as the smaller one of the two rings is inserted inside the width, and further An elliptical cam is provided inside through a ball bearing, and the elastic ring is bent into an elliptical shape by the elliptical cam through the ball bearing, and the long axis connects the inner teeth of the input/output cylinder with the elastic ring. The external teeth of the ring mesh and transmit power, and the relative speed between the cylinder with a different number of teeth and the elastic ring is controlled by the difference in the number of teeth, the input/output direction of the cylinder, and the rotational direction of the cam. Instead, it is provided in the differential gear mechanism that increases and decelerates the output side of the cylinder, and in addition to the drive system for power transmission, a continuously variable gear mechanism is provided between the roll serving as the circumferential speed reference and the differential gear mechanism. A drive system is provided, a continuously variable transmission is incorporated into the continuously variable transmission drive system, and rotation on the output side of the continuously variable transmission is applied to the oval cam of the differential gear mechanism at a variable speed. This is a continuously variable transmission device for a longitudinal stretching machine for plastic film, in which the rotation speed of the output side of the cylinder of the differential gear mechanism is changed, and the rotation speed of the rolls to be driven can be varied steplessly.

[5] Embodiment An embodiment of the present invention will be described with reference to drawings. FIG. 1 is a front view of a longitudinal stretching machine in which rolls 11 to 20 are arranged in a staggered arrangement, and all the rolls are heated by a heat medium. There is. The rolls 11 to 16 are preheating rolls, and the roll 17 is a preheating roll.
to roll 20 are rolls for heat setting after stretching. The longitudinal stretching of the film is mainly carried out by roll 16.
and roll 17. The preheating rolls from roll 11 to roll 16 are roll 16.
From roll 15 to roll 11 based on the circumferential speed of
Up to 5% stepless roll between each roll up to 11
The side is designed to be able to decelerate. Also roll 1
The heat set rolls from 7 to 20 are configured so that the speed of rolls 18 to 20 can be increased steplessly by a maximum of 5% simultaneously based on the circumferential speed of roll 17. Next, the continuously variable transmission device on the preheating roll side will be described. The number of rolls serving as the peripheral speed reference is 16, and one end of the shaft of this roll 16 is connected to a drive source 21 as shown in FIG. On the other end, roll 1
A power transmission gear 22 provided for driving the rollers 5 to 11 and a timing belt pulley 23 provided for continuously variable transmission of the rollers 15 are attached. The power transmission gear 22 is an idler gear 2
4. Gear 26 fixed to circular spline S of differential gear mechanism 25 (differential unit manufactured by Harmonic Drive Systems);
the circular spline S having spline-shaped teeth on the inner periphery; the flexspline 27 having teeth on the outer periphery having the same pitch of teeth as the circular spline S and having the same number of teeth, two fewer than the number of teeth of the circular spline S; Flexspline 27
A circular spline D having the same pitch and the same number of teeth, a gear 26a fixed to the circular spline D, and a gear 28 attached to the shaft of the roll 15 sequentially mesh with each other to drive the roll 15. Further, the timing belt pulley 23 is connected to a pulley 31 provided on an input shaft 30 of a continuously variable transmission 29 via a timing belt 32. Furthermore, the output shaft 33 of the continuously variable transmission 29
Pulleys 36 and 37 are attached to the central shaft 35, which passes through the central hole of the cam 34 of the differential gear mechanism 25 and is fixed to the cam 34 with a key, and are connected by a timing belt 38, and are rotated by the central shaft 35. It is beginning to give. Between roll 15 and roll 14, between roll 14 and roll 13, between roll 13
The drive system between the roll 12 and the roll 12 and between the roll 12 and the roll 11 is the same as the drive system between the roll 16 and the roll 15 described above. However, there is no drive source from roll 15 to roll 11, and power is transmitted from the roll 16 shaft. Furthermore, the input/output direction of the differential gear mechanism 25 incorporated in the drive system between the rolls 17 and 18 is opposite to the direction between the rolls 16 and 15, with the circular spline D side being the input and the S side being the output side. (not shown).

With the structure as described above, the film 39 introduced into the longitudinal stretching machine advances in the direction of the arrow in a staggered manner from roll 11 to roll 20, and is preheated (heated) to a predetermined temperature. , stretching after preheating, and heat setting after stretching to complete the stretching. Film 39 heated with preheating roll
As it goes from the roll 11 side to the roll 16 side, it stretches and becomes slack due to the above-mentioned reason. In order to prevent this slack, roll 1 is removed from the roll 11 side.
The peripheral speed of the rolls is steplessly increased (speed-changed) by a maximum of 5% between rolls as it moves toward the 6th side. However, the roll peripheral speed standard of this preheating roll portion is based on the roll 16. That is, the roll 16 is based on the roll 16.
The speed between each roll from 1 to 11 is steplessly reduced by a maximum of 5%. The speed change is performed by changing the rotation of the output side of the continuously variable transmission 29 provided in the continuously variable transmission drive system on a central shaft 35 provided through the cam 34 of the differential gear mechanism 25 provided in the power transmission drive system. By changing the rotation of the cam 34 and changing the relative speed between the circular spline S and the flexspline 27, the rotation of the output side circular spline or S is changed. The difference in increase/deceleration is the differential gear mechanism 2
It is determined by the difference in the input/output direction of the circular splines S and D in No. 5 and the difference in the rotational direction of the cam 34. If the S side is the input and the D side is the output, and the rotational direction of the cam 34 is the same as the S side, the deceleration occurs, and the D side decelerates. When the input and S sides are outputs and the rotational direction of the cam 34 is the same as the D side, the speed increases, and the rotation speed on the output side of the differential gear mechanism 25 is expressed by the following equation.

N _D = R+1/RN _S -1/RN _W (For deceleration) N _S = R/R+1N _D +1/R+1N _W (For speed increase) In the above equation, N _D : Circular spline of differential gear mechanism 25 Z D rotation speed, N _S : Circular spline S rotation speed of the differential gear mechanism 25,
R: Speed ratio of the differential gear mechanism 25; N _W : Input rotation speed of the cam 34 of the differential gear mechanism 25. In the case of deceleration in this embodiment (Fig. 2), gears 22, 24, 2
6, 26a and 28 are the same gears and the differential gear mechanism 2
5 speed ratio 160, rotation speed of the roll 16 45 rpm, rotation speed of the central shaft 35 of the cam 34 of the differential gear mechanism 25 4
5 to 405 rpm, the rotation speed of roll 15 is
45 to 42.75 rpm.

[6] Effects of the invention The present invention enables the selection of optimal conditions for the stretching ratio and changes in operating conditions using unknown new materials.
When it is necessary to change the roll circumferential speed, the roll circumferential speed can be changed easily in a shorter time and with high accuracy.

[Brief explanation of the drawing]

FIG. 1 is a front view showing an embodiment of a longitudinal stretching machine for plastic film, and FIG. 2 is a diagram showing a part of a drive system diagram of a preheating roll section. 11 to 20... Roll, 25... Differential gear mechanism, 27... Flex spline, 29... Continuously variable transmission, 34... Cam, S, D... Circular.
spline.

Claims (1)

[Claims] 1. In a longitudinal stretching machine that brings the film surface into contact with the surfaces of a plurality of heated rolls and applies a circumferential speed difference to the rolls to stretch and stretch the film in the longitudinal direction, A drive system for power transmission provided between the roll to be driven and the roll serving as the circumferential speed reference has spline-shaped teeth with different numbers of teeth on the inner periphery of the cylinder based on the roll serving as the circumferential speed reference. Two cylinders for input and output are arranged side by side on the same axis, and inside the width of these two cylinders, there is a tooth of the two cylinders with the same pitch and the same number of teeth as the teeth of the cylinder. An elastic ring having the same number of teeth as the one with fewer teeth is inserted, an elliptical cam is provided inside the elastic ring via a ball bearing, and the elliptical cam moves the elastic ring. It is bent into an elliptical shape via a ball bearing, and the inner teeth of the input/output cylinder mesh with the outer teeth of the elastic ring at the long axis to transmit power,
Due to the difference in the number of teeth, the input/output direction of the cylinder, and the rotation direction of the cam, the relative speed between the cylinder with a different number of teeth and the elastic ring is changed, and the output side of the cylinder is increased/decelerated. A dynamic gear mechanism is provided, and in addition to the power transmission drive system, a continuously variable transmission drive system is provided between the roll serving as the circumferential speed reference and the differential gear mechanism, and the continuously variable transmission drive system is provided. A continuously variable transmission is incorporated in the cam, and the rotation on the output side of the continuously variable transmission is applied to the elliptical cam of the differential gear mechanism in a variable speed, so that the rotation on the output side of the cylinder of the differential gear mechanism A continuously variable transmission device for a longitudinal stretching machine for plastic film, characterized in that the number of rotations of the rolls to be driven can be varied steplessly.