JP2009133026A - Method for knitting knitted fabric and knitting machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for knitting a knitted fabric with which tension is controlled simultaneously with change of tension by controlling tension applied to a knitting yarn by a simple mechanism interlocked with acceleration and deceleration in movement of a knitting yarn and the variation of tension can be reduced even when the variation speed of tension is high. <P>SOLUTION: The method for knitting the knitted fabric comprises using a knitting stand apparatus (10) and tension controllers (4-6) for controlling the tension of a knitting yarn (1) to be sent to the knitting stand apparatus in which the tension controllers (4-6) are interlocked with acceleration and deceleration of a moving guide roll (13) in the knitting part (11) of the knitting stand apparatus (10) so as to control tension applied to the knitting yarn (1). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a knitting method and a knitting machine suitable for a knitting yarn, particularly a hollow fiber membrane knitted fabric using a hollow fiber membrane as a knitting yarn.

  A method using a dancer roll is widely known as a method for applying a constant tension to a filamentous material. For example, as a method for controlling the winding tension of a filamentous material, as described in Japanese Patent Laid-Open No. 6-255858 (Patent Document 1), a guide roller that guides the linear body on the traveling path of the linear body is provided. A tension-applying dancer roll is provided vertically below the guide roller. The dancer roll is rotatably supported at the tip of an arm coupled orthogonally to the rotation axis of the torque motor, and detects the rotation angle with an arm rotation angle detector even during winding, A predetermined moment is applied to the rotating shaft of the torque motor to move the arm up and down to apply a predetermined tension to the yarn. Furthermore, a tension detector that measures the tension of the running yarn is arranged downstream of the dancer roll, and the detected tension is fed back to the control unit to control the rotation of the torque motor. The tension of the yarn is controlled constant or arbitrarily.

  Also, in the sheet material supply process made of paper or film, as disclosed in, for example, Japanese Patent Application Laid-Open No. 2003-212406 (Patent Document 2), the tension of the conveyed sheet material is adjusted using a dancer roll. I have control. That is, according to Patent Document 2, the position detector that detects the position of the dancer roll in the vertical direction and the position of the dancer roll in the vertical direction based on the detected position are set in advance from the detection position. A position control circuit for calculating a position correction amount for returning to the position, a dancer pressure correction circuit for calculating a moving inertia force of the dancer roll while the dancer roll returns from the detection position to the reference position based on the position correction amount, and movement A pressure setter that adjusts the dancer pressure based on the inertial force, even if the position of the dancer roll in the vertical direction is displaced from the reference position and returns from the displacement position to the reference position. A stable tension can be applied to the sheet material by correcting the change in the dancer pressure due to the moving inertia force.

  By the way, the knitted fabric which used the hollow fiber membrane mainly used for the process of drinking water is mainly known for the cartridge of the water purifier conventionally. This hollow fiber membrane knitted fabric has a width of about 20 cm at most, and is used for filtering suspensions contained in liquids such as river water, lake water, well water, sewage, irrigation water, wastewater, etc. In the hollow fiber membrane module used in the above, the folded length of the hollow fiber membrane is as long as 40 to 200 cm.

  When forming a wide hollow fiber membrane knitted fabric, when the hollow fiber membrane as a weft traverses from side to side, abnormal tension is likely to occur at the turning point, and the membrane may be damaged. That is, the operation is repeated in which the supply speed of the hollow fiber membrane instantaneously becomes zero at the turn-back end, and then is accelerated and becomes zero again at the other end. This rapid speed change increases as the traverse width increases. Even if a very small part of the hollow fiber membrane is damaged by the abnormal tension resulting from this speed change, the entire hollow fiber membrane knitted fabric becomes a defective product.

  In order to absorb this tension fluctuation, a method of changing and absorbing the yarn speed of the driving source in conjunction with the vertical movement of the dancer roll disposed on the yarn supply side can be considered. However, if the speed is extremely low, the tension fluctuation can be absorbed. However, when a dancer roll is operated when operating at a weft speed of about 20 m / min to 100 m / min of a normal production machine, when traversing with such a wide width, The speed fluctuation and the absorbed yarn length increase in proportion to the knitting width. Accordingly, the amount of movement of the dancer roll increases, and the dancer roll is required to move within the increased range of movement in a short time without affecting the weft.

  However, for example, assuming the movement of the dancer roller in the vertical direction, if the dancer roll that maintains the appropriate tension by the mass of the dancer roller is then absorbed quickly by the traverse guide, It must follow in the opposite direction with the inertial force of the previous motion applied in addition to the weight. As a result, both forces give excessive tension to the weft, and the dancer roll cannot follow and cannot absorb the tension fluctuation. Even if such a hollow fiber membrane bundle is traversed at a high speed and a wide width of 40 to 150 cm, a knitting device capable of knitting a wide hollow fiber membrane knitted fabric with a tension that does not always damage the hollow fiber membrane, for example, Japanese Patent Laid-Open No. 6-210141 (Patent Document 3) proposes a method that does not use a dancer roll.

The hollow fiber membrane knitting device disclosed in Patent Document 3 is such that the traveling hollow fiber membrane fed from the feed roller is blown upward together with air through the nozzle, and the top position of the traveling parabola of the hollow fiber membrane that falls after being blown up Is detected by detecting means arranged in a plurality of stages above and below, and a signal emitted from the detecting means arranged between the uppermost stage and the lowermost stage is fed back to adjust the speed of the feed roller. When the hollow fiber membrane deviates further above and below the positions of the uppermost and lowermost stages, a signal for stopping the machine base is issued from those detecting means.
JP-A-6-255858 JP 2003-212406 A JP-A-6-210141

  However, in the method described in Patent Document 1 described above, since the tension is controlled so as to eliminate the change after detecting the value of the change in tension, it is inevitable that the tension changes in principle. Furthermore, when the speed at which the tension changes is high, there is a problem that the amount by which the tension changes increases. Similarly, in the method described in Patent Document 2 described above, since the tension is controlled after detecting the displacement of the dancer roller, a change in the tension when the dancer roll position is displaced is unavoidable.

  The method described in Patent Document 3 requires a large amount of air to blow upward when the weight per unit length is large and the air resistance is small (for example, when the weight is 2 g / m or more and a monofilament). Therefore, it is difficult to make equipment.

  The present invention has been made in view of these problems, and by controlling the tension applied to the knitting yarn by a simple operation linked to acceleration and deceleration during movement of the knitting yarn, the tension is controlled simultaneously with the change in tension. An object of the present invention is to provide a knitting method and a knitting machine for a knitted fabric that can reduce the amount of change in tension even when the rate of change in tension is high.

  The above object includes a knitting device and a tension control device that controls the tension of a knitting yarn supplied to the knitting device, which is the first basic configuration of the present invention, and the tension control device includes the knitting device. This is solved by a knitting method of a knitted fabric characterized by comprising controlling tension applied to the knitting yarn in conjunction with acceleration and deceleration during knitting.

According to a preferred aspect of the present invention, the tension is lowered when the knitting portion of the knitting device is accelerated, and the tension is increased when the knitting portion is decelerated.
According to another preferred aspect of the present invention, the tension control device is a dancer roller.
According to still another preferred embodiment of the present invention, it is preferable that the filamentous material is a hollow fiber membrane.

  The above problem is a second basic configuration of the present invention, a moving guide roll that moves the guide position of the knitting yarn to be knitted into the knitted fabric and traverses the knitting yarn, and a guide roll drive unit that moves the moving guide roll. A dancer roller that applies tension to the knitting yarn, a tension control unit that controls the tension applied to the knitting yarn by the dancer roller, and a control unit that interlocks driving of the moving guide roll and tension control. The knitting machine can be effectively solved.

  As a preferred mode, the dancer roller is coupled to the tension control unit via a wire, the tension control unit includes a torque motor for winding / releasing the wire, and the control unit is set in advance. A storage unit storing a correlation expression between the traverse length of the moving guide roll, the traverse acceleration / deceleration pattern of the moving guide roll, and the yarn tension fluctuation pattern; and a calculation unit that calculates the tension of the knitting yarn based on the correlation expression. The tension control unit receives the calculation result of the calculation unit, controls the rotational torque of the torque motor, and controls the knitting yarn tension by the dancer roller based on the driving of the moving guide roll. The knitting device is preferably a Russell knitting machine.

Effects of the invention

  The moving guide roll reciprocates between the warp knitting needles, and the knitted fabric is knitted by repeating knitting with warps at both ends thereof. As the moving guide roll moves, the knitting yarn is pulled out to the knitting device via the dancer roller. The moving guide roll has zero speed at both ends of the reciprocating position, and repeats acceleration and deceleration when moving between the reciprocating positions. As a result, the knitting yarn is repeatedly accompanied by the movement guide roll and repeatedly accelerates and decelerates. The tension applied to the knitting yarn during the acceleration / deceleration of the knitting yarn varies greatly depending on the load of the dancer roller, the inertial force due to the rotation of the dancer roller, and the inertial force when the dancer roller moves up and down.

  This variation in tension, particularly in a structure having fine holes such as a hollow fiber membrane, opens a large hole based on the variation in tension, and greatly degrades the quality of the hollow fiber membrane. On the other hand, in the production of the knitted fabric 15, it is necessary to increase the speed at which the knitted fabric 15 is knitted in order to increase the productivity. As the speed of the moving guide roll increases, the fluctuation of acceleration / deceleration also increases.

  In the conventional method, after detecting the tension of the knitting yarn, the method of controlling the tension to be constant causes a time difference between the detection of the change in the tension of the knitting yarn and the control of the tension. The impossible changes are also increased. When the change in tension becomes large, the quality of the knitted fabric and the quality of the knitting yarn are impaired.

  In the present invention, a tension control unit is connected to the dancer roller, and the tension control unit controls the lift position of the dancer roller. On the other hand, the control unit includes, for example, a storage unit that stores a correlation expression between a traverse length of the movement guide roll set in advance, a traverse acceleration / deceleration pattern of the movement guide roll, and a thread-like tension fluctuation pattern, and a knitting based on the correlation expression. A calculation unit for calculating the tension of the yarn, and the tension control unit controls the knitting yarn tension by the dancer roller in response to the calculation result by the calculation unit. Therefore, according to the present invention, the constant tension is maintained by controlling the knitting yarn tension simultaneously with the change in the moving speed of the moving guide roll without providing a detection means or the like.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is an explanatory view schematically showing an example of a knitting apparatus and a knitting method according to the present invention.
The knitting yarn 1 is supplied to the knitting device 10 by a yarn feeding device (not shown). A dancer roll device 2 is arranged in the middle of supplying the knitting yarn 1. The dancer roll device 2 is suspended from a first and second pair of guide rolls 3 arranged before and after the knitting yarn supply path, and a knitting yarn 1 which is guided by the pair of guide rolls 3 and hangs down in a U-shape. The dancer roller 4 that freely rotates, a wire 5 having an upper end fixed to the shaft portion of the dancer roller 4, and a tension control unit 6 connected to the lower end of the wire 5 are provided.

  In the dancer roll device 2 according to this embodiment, the dancer roller 4 is configured to be pulled vertically downward by the tension control unit 6 via the wire 5. The tension control unit 6 may use a torque motor and an arm as shown in Patent Document 1, or may use a cylinder as shown in Patent Document 2, but the wire 5 and the wire It is preferable to use a torque motor that winds 5 because the tension control unit 6 can be made compact. The voltage applied to the electromagnetic clutch is controlled by the control unit 7.

  In the present embodiment, the wire 5 is configured to be wound around a torque motor via an electromagnetic clutch (not shown) that can control the tension applied to the wire 5, and the wire 5 is wound by a voltage applied to the electromagnetic clutch. The winding torque can be controlled. When the torque is increased, the tension applied to the wire 5 is increased, and the tension of the knitting yarn 1 applied to the dancer roll device 2 is increased.

  The knitting device 10 includes first to third feeding rolls 12 that feed the knitting yarn 1 into the knitting unit 11, a moving guide roll 13 that is arranged in the knitting unit 11 and traverses the knitting width direction to the left and right, and the same moving guide. A moving guide roll drive unit 14 for moving the roll 13 and a warp knitting needle 16 for knitting the knitting yarn 1 to create a knitted fabric 15 are provided.

  The movement guide roll 13 is fixed to the timing belt 17 via a jig 18 and is moved by driving the timing belt 17. The timing belt 17 is connected to an electric motor such as a servo motor or an inverter motor of the moving guide roll driving unit 14. The control unit 7 traverses the moving guide roll 13 left and right by rotating the moving guide roll driving unit 14 forward or backward. The moving guide roll drive unit 14 is preferably an electric motor capable of normal rotation and reverse rotation and capable of controlling the speed and acceleration, and a servo motor or an inverter motor can be used. It is preferable to use a servo motor that can be accurately controlled.

  As shown in FIG. 2, the knitted fabric 15 is knitted by repeatedly moving the moving guide roll 13 between the warp knitting needles 16 and knitting both ends with the warp yarns 19. When the moving guide roll 13 moves, the knitting yarn 1 is pulled out from the dancer roller 4 to the knitting device 10. The moving guide roll 13 has zero speed at both ends of the reciprocating position, and the moving guide roll 13 repeats acceleration and deceleration when moving between the reciprocating positions. The knitting yarn 1 is also repeatedly accelerated and decelerated with the movement guide roll 13. Here, for the warp 19, for example, polyethylene multifilament is used.

  When the knitting yarn 1 is accelerated, the tension applied to the knitting yarn 1 is not only the load of the dancer roller 4 of the dancer roll device 4 but also the inertial force that rotates the dancer roller 4 and the inertia that moves the dancer roller 4 vertically upward. Power is added. Similarly, when the knitting yarn 1 decelerates, the inertial force due to the rotation of the dancer roller 4 and the inertial force in the vertically upward direction of the roller 10 decrease from the load of the dancer roller 10 of the dancer roll device 4, and the tension greatly decreases. To do. That is, when the moving guide roll 13 is accelerated and decelerated, the tension applied to the knitting yarn 1 varies greatly.

  In the knitting of the knitted fabric 15, if the tension of the knitting yarn 1 is too low, the knitting yarn 1 is loosened at the knitting portion 11, the width of the finished knitted fabric 15 is not determined, and the quality of the knitted fabric 15 is deteriorated. On the other hand, if the tension of the knitting yarn 1 is too strong, the knitting yarn 1 is damaged and the quality of the knitting yarn 1 is deteriorated. In particular, in a structure having fine pores such as a hollow fiber membrane, a large hole is formed on the membrane surface by strong tension, and the quality as a hollow fiber membrane is greatly deteriorated. Therefore, it is necessary to maintain a proper tension constant for the knitting yarn 1.

  In the production of the knitted fabric 15, in order to increase the productivity, it is necessary to increase the speed at which the knitted fabric 15 is knitted, that is, it is necessary to increase the speed of the moving guide roll 13. As the speed of the moving guide roll 13 increases, the acceleration increases, the amount of change in tension applied to the knitting yarn 1 increases, and the change speed increases.

  That is, in the conventional method of controlling the tension of the knitting yarn 1 to be kept constant after the tension of the knitting yarn 1 is detected, the amount of change in the tension of the knitting yarn 1 must be detected in advance. This is unavoidable, and the response speed output from the tension control unit is constant and unique to the control unit. Therefore, when the speed at which the tension changes increases, the amount of change that cannot be corrected due to control delay increases. As the change in tension increases, the quality of the knitted fabric 15 and the quality of the knitting yarn 1 are impaired.

  In the present embodiment, the dancer roller 4 and the tension controller 6 are coupled via a wire 5. The tension control unit 6 includes a torque motor that winds / releases the wire 5, and the control unit 7 has a traverse acceleration / deceleration pattern of the moving guide roll 13 and a traverse length of the moving guide roll 13 set in advance. And a storage unit 7a that stores a correlation formula between the yarn tension variation pattern and a calculation unit 7b that calculates the tension of the knitting yarn based on the correlation formula. The tension control unit 6 receives the calculation result by the calculation unit 7b, controls the rotational torque of the torque motor, and controls the knitting yarn tension by the dancer roller 4 based on the driving of the moving guide roll 13.

  Torque control of the torque motor is performed by using an electromagnetic clutch (not shown) and controlling the voltage sent to the electromagnetic clutch in accordance with an instruction from the control unit 7. Further, the control unit 7 controls the moving speed and acceleration of the moving guide roll 13. As a result, it is possible to simultaneously perform the timing for executing the control for accelerating and driving the moving guide roll 13 and the control for reducing the tension of the knitting yarn 1 without providing any special detection means. Similarly, it is possible to simultaneously perform the timing for executing the control for decelerating and driving the moving guide roll 13 and the control for increasing the tension of the knitting yarn 1.

  The timing and amount at which the tension of the knitting yarn 1 is increased or decreased by the tension control unit 6 are the timing at which the tension of the knitting yarn 1 changes when the movement guide roll 13 is driven without using the tension control unit 6 in advance. The amount is measured or calculated, and programmed in the control unit 7 so as to cancel this change. With this configuration, even when the speed at which the tension applied to the knitting yarn 1 changes is high, it is possible to control the yarn tension to be kept constant.

  As described above, according to the present invention, by controlling the tension applied to the knitting yarn 1 in conjunction with the acceleration and deceleration of the knitting yarn 1, the tension is controlled at the same time as the tension is changed. Even when the rate of change is fast, the amount of change in tension can be reduced.

It is explanatory drawing which shows roughly an example of the knitting apparatus used to implement this invention, and its knitting method. It is a front view of the example shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Knitting yarn 2 Dancer roll apparatus 3 1st and 2nd pair of guide roll 4 Dancer roller 5 Wire 6 Tension control part 7 Control part 7a Memory | storage part 7b Calculation part 10 Knitting apparatus 11 Knitting part 12 1st-3rd Feeding roll 13 Moving guide roll 14 Moving guide roll drive unit 15 Knitted fabric 16 Warp knitting needle 17 Timing belt 18 Jig 19 Warp

Claims (7)

A knitting device and a tension control device for controlling the tension of the knitting yarn supplied to the knitting device,
The tension control device controls the tension applied to the knitting yarn in conjunction with acceleration and deceleration in the knitting portion of the knitting device,
A method for knitting a knitted fabric characterized by comprising:   The method of knitting a knitted fabric according to claim 1, wherein the tension is controlled by decreasing the tension when the knitting portion is accelerated and increasing the tension when the knitting portion is decelerated.   The knitting method for a knitted fabric according to claim 2, wherein the tension control device includes a dancer roller.   The knitting method for a knitted fabric according to claim 3, wherein the knitting yarn is a hollow fiber membrane.   A moving guide roll that traverses the knitting yarn while moving the guide position of the knitting yarn to be knitted on the knitted fabric, a guide roll driving unit that moves the moving guide roll, a dancer roller that applies tension to the knitting yarn, and a knitting by the dancer roller A knitting machine comprising: a tension control unit that controls tension applied to a yarn; and a control unit that interlocks drive control of a moving guide roll and knitting yarn tension control. The dancer roller is coupled to the tension controller via a wire,
The tension control unit includes a torque motor that winds / releases the wire,
The control unit includes a storage unit storing a traverse length of the moving guide roll set in advance, a traverse acceleration / deceleration pattern of the moving guide roll, and a yarn-like tension fluctuation pattern, and a tension of the knitting yarn based on the correlation equation And an arithmetic unit for calculating
The tension control unit receives a calculation result by the calculation unit, controls the rotational torque of the torque motor, and the knitting yarn tension by the dancer roller is controlled based on driving of a moving guide roll.
The knitting machine according to claim 5, wherein:   The knitting machine for a knitted fabric according to claim 5 or 6, wherein the knitting machine is a Russell knitting machine.

Images