DE4104087A1 - Electronic wire tension regulator for coil winding device - has successive tensioning braking and dynamic regulation stages - Google Patents

Abstract

The tension regulator for a coil winding device ensures a constant wire tension for all phases of the winding process. The wire fed off from a supply reel (1) is passed through a wire pulling device (4...6) and a wire tensioning device (7...9), followed by a braking device (10...13) and a dynamic regulator (14...19). The tensioning device (7...9) uses a deflection roller (9) acted on by a spring lever system (7,8) for providing a constant tension, the braking device (10...13) using a second deflection roller (12) coupled to an electric motor (10). The dynamic regulator uses a freely movable roller (16) supported between 2 springs and magnets (14,15). USE - For winding round or rectangular coil.

Description

The invention relates to an electronic wire tension control device for reproducible setting and regulation of wire tension to wrap a wire or synthetic fiber around a round or rectangular coil with the help of a commercially available Winding machine. The entire winding device consists of one Wire supply spool from which the wire to be wound comes from followed from the wire control device according to the invention, by which wire coming from the supply reel is guided, a wire laying device, the wire emerging from the wire control device for coil formation in brings the required position and a rotating axis that carries the bobbin to be wound. The wire control device according to the invention should be the particularly angular coils during the winding process occurring blows as well as when re-equipping the winding machine occurring with coils Compensate for wireless, so that a tearing of the sometimes thin Wire up to 1/100 mm in diameter is avoided. Previous mechanical and electronic processes were mostly able to create the slowly emerging wireless catch the high-frequency beats (about 1500 Hz at 10,000 rpm), that arise when winding square coils, eluded however, due to the inertia of the mechanical actuators control technology. Individual processes are known from:

DE 24 14 302 AS, consisting of a mechanical with the winding machine connected cam wheel that the different path lengths of the wire in square coils. Cons of this Procedures are the necessary coupling to the winding machine and the difficult to implement shape of the cam wheel, which for each Coil shape must be determined again.

DE 29 51 917 PS, consisting of a coupled to the winding machine electronic position sensor, which consists of the Known coil shape control device in phase an electromechanical Wire brake controls. The main disadvantages of this method are the electronic ones Coupling to the winding machine and ignoring the actual wire pull. Therefore, this system cannot Deviations from the target values react as there are no suitable ones Measuring devices are provided.

DE 33 36 970 PS, consisting of a pneumatically driven Wire brake with a wire loop stretched by an air stream. This method offers the advantage of an almost massless Wire brake and thus good control properties, proves but is not economical due to the high compressed air requirement.

DE 35 36 363 PS, consisting of a wire pre-brake with counter the wire running direction rotating brake disc and an electric adjustable wire brake depending on the setpoint and actual value of the Wire drawing. This method offers good control properties in the Standstill of the wire as well as with round coils; with square coils However, due to inertia, no regulation can be made respectively. In addition, there are major signs of wear on the Watching the brake disc.

DE 34 36 187 PS, consisting of a mechanical spring arm, the additionally regulates the braking force of a brake roller due to its position with pneumatically adjustable  Wire drawing. This procedure generally offers sufficient control properties however, no regulation can be made by the resonance of the lever / spring system high-frequency vibrations.

Several other processes are known (DE 23 18 884 PS, DE 27 40 723 PS, DE 29 19 145 PS), but the similar defects as the have methods described above.

In general, the following problems arise when winding electrical coils on:

• - The wire runs when the bobbin is replaced in the winding machine slowly back a few centimeters.
• - When the winding machine starts and brakes, the wire becomes accelerated or braked evenly. However, in commercial winding machines often have brakes in the winding axis can be used shortly after / before the machine stops Strong jerks occur on the axis.
• - Low frequencies occur during the entire winding process Vibrations due to changes in speed of the winding machine, Tolerances of the coil shape and the wire thickness.
• - When winding square coils there are also high-frequency periodic vibrations with small amplitude due to the impact of the wire on a coil edge. When using a Lever / spring system, over which the wire is guided, is created by fast winding of square coils additionally a chaotic part of vibrations caused by the inertia or Resonance of this system. With quick wire changes the lever arm lifts off the wire and hits in an unknown Phase of the wire acceleration. It can be so at high Winding speeds chaotic vibrations occur whose amplitude exceeds the periodic vibrations can.
• - During the winding process at high speeds a brief jamming of the wire in the wire supply occurs, which results in a short and strong jerk on the wire Has.

The invention is therefore based on the following objects:

• - Constantly regulate slow changes in wire tension taking into account different coefficients of friction the actuators at standstill as in winding mode.
• - Towards the winding machine a few centimeters of wire at a standstill to record the wire running direction.
• - To compensate for the periodic excitation when winding square coils taking into account the mechanical time constants of the Actuators.
• - Possibly. recognize occurring chaotic vibrations and balance.

Furthermore, the realization of the invention Wire control device to observe the following points:

• - A mechanical and electronic coupling of the wire control device to the winding machine must be avoided in order to to ensure wide and universal application space.
• - Wire tension and other parameters must be easy and above all be reproducibly adjustable in order to easily convert the to ensure the entire winding device on a different coil type.  
• - No wear parts should be included, as at wire speeds over 10 m / s and continuous operation the consumption of the same would be uneconomical. The wire must never be used at high Speeds are subject to high friction.
• To achieve these tasks, the wire control device according to the invention contains:
• - A wire cleaner, consisting of two pressing against each other Felting or brushing through which the wire originating from the wire supply to be led. The pressure force of the wire cleaner can be electromagnetic can be adjusted to the friction at high To reduce wire speeds
• - A wire tensioning device, consisting of a spring arm with Deflection roller over which the wire coming from the wire cleaner runs becomes,
• - A wire brake device consisting of an electronic controlled motor, on the axis of which there is an electronic angle sensor and a roll is attached. The one from the wire tensioner Originating wire is (possibly several times) around the roll looped,
• - A dynamic wire control device consisting of a linear and especially low-mass suspended between two or more springs Roll, its position by means of an electronic position sensor (e.g. using the optoelectronic triangular method). The The base of at least one spring can be adjusted electromagnetically be that continuous spring tensions are generated can. The wire coming from the wire brake device becomes led over the role
• - A phase compensation device consisting of an electromechanical adjustable pen or roller, about which of the dynamic control device is guided wire. The electromechanical drive can, for. B. from a piezoceramic Element exist
• - A wire pickup, over which the of the phase compensation direction originating wire is guided. A strain gauge can be used here as a sensor serve. The wire coming from the wire tension sensor becomes the Winding machine fed.

The wire tensioning device can be constructed differently as soon as a pre-tensioning of the wire with constant or roughly adjustable Strength is possible and the inclusion of a certain distance Wire is guaranteed against the wire running direction.

The dynamic control device can be constructed differently, as soon as a low-inertia suspension of the Wire is done and the position of the spring-loaded pulley electronically can be determined.

The phase compensation unit can be constructed differently as soon as a positive acceleration of the wire at high speed can be exercised. It’s still considered positive if all technically related pulleys are low in mass and on one slightly resilient suspension are attached.

Significant advantages of the wire control device according to the invention are:

• - Rapid changes in wire tension can occur in the low-mass spring system the dynamic control device caught directly will. This is achieved through  a high natural frequency of the mass / spring system. This method offers much shorter time constants than the widely used ones Levers / spring systems.
• - The due to the inertia of the pulley caused in the spring system of the dynamic control unit Phase shift from wire tension to wire speed can with periodic vibrations by pre-accelerating be corrected in the phase compensation unit.
• - Chaotic vibrations are caused by balancing the phase shift largely avoided. Nevertheless contained chaotic disturbances can easily on the wire tension sensor recognized and by quick counter-rules on the phase compensation unit their effects are greatly reduced.
• - Slow wire voltage changes with large amplitude can recognized at the position of the dynamic control unit and by changing the braking force of the motor in the wire brake unit Getting corrected.
• - Wireless when the winding machine is at a standstill Moving the motor backwards in the wire brake unit and collecting can be avoided in the wire tensioning device. In addition can still some distance wire from the dynamic control device be included.
• - Wear in the wire cleaning device is reduced of the contact pressure avoided at high wire speeds.
• - The individual transducers (angle transducer - wire brake device, Position sensor - dynamic control device, wire tension sensor) allow the electronic evaluation of the variables: absolute Wire drawing, dynamic wire drawing change, wire speed and Wire running direction. So it can be a complete control of the wire tension take place regardless of the winding machine used.
• - If the wire is jammed in the wire supply for a short time the wire tensioner largely absorb this jerk that Spring system of the dynamic control device can by its own wire stock to compensate for this short-term wire shortage.
• - The user only has the parameters of the electronic control Notify wire pull and spool shape. Because of the complexity the electronic control only a processor-controlled system is a reproducible and easy setting the parameter ensures.

To explain the invention, an exemplary embodiment of the wire control device according to the invention as well as the wire supply and the winding machine is shown in FIG. 1 in a schematic representation. The winding structure shown in FIG. 1 contains a wire supply ( 1 ), from which a wire ( 2 ) to be wound into a coil ( 25 ) is drawn off. The originating from the wire supply (1) wire (2) first passes through the wire cleaning means which against each other pressing of two felts or brushes is (4). The wire ( 2 ) is passed between the felts / brushes. The spring ( 6 ) together with the magnet ( 5 ) generates an adjustable contact pressure so that the friction of the wire can be reduced at high wire speeds. This measure prevents the wire from overheating and the wear on the felts ( 4 ).

The wire ( 2 ) originating from the wire cleaning device now passes through the wire tensioning device via the roller ( 9 ) which is attached to the lever arm ( 7 ). The lever arm ( 7 ) is tensioned by the spring ( 8 ) so that the wire ( 2 ) receives a low, relatively constant bias. The system of wire cleaning and wire tensioning device is able to take up a few centimeters of wire against the wire running direction ( 3 ). This is necessary in order to avoid slippage on the roller ( 12 ) of the wire brake device in the event of a wire return.

In the exemplary embodiment shown ( 10, 11, 12, 13 ) form the wire brake device. The wire ( 2 ) originating from the wire tensioning device is possibly passed several times around the roller ( 12 ), which is connected via the shaft ( 11 ) to the motor ( 10 ) and the angle sensor ( 13 ). The motor ( 10 ) is electronically torque-controlled in the exemplary embodiment, so that a wire tension that is directed counter to the wire running direction ( 3 ) arises. The direction of rotation, the speed and the acceleration of the wire can be determined electronically via the rotation angle sensor ( 13 ). It is considered advantageous if the roller ( 12 ) has as little mass as possible and has a high coefficient of friction on the running surface. The wire brake device serves as an actuator for the middle wire pull and as a drive in the event of a return of the wire counter to the normal wire running direction ( 3 ).

The wire is then passed over the roller ( 16 ), which is suspended freely suspended between the springs ( 14, 15 ). The base point of the spring ( 14 ) can be adjusted by means of an indicated electromechanical drive ( 17 ). This setting is proportional to the desired mean wire tension, so that the roller ( 16 ) is at a defined zero position. The position of the roller ( 16 ) can be determined via the position measuring system ( 18 ). If the wire tension decreases, the roller ( 16 ) moves in the direction of the spring ( 14 ) and the electronics increase the torque of the motor ( 10 ). As a result, the roller ( 16 ) moves back towards the zero position. The procedure is reversed in the case of increased wire tension. A control method similar to a PID controller is considered advantageous. If a change in the (target) wire tension is desired, the base point of the spring ( 14 ) is adjusted by an electric motor ( 17 ) and the torque of the motor ( 10 ) is adjusted. To reduce vibrations transverse to the normal direction of movement of the roller ( 16 ), rods ( 19 ) can be hung in the center of the spiral springs ( 14, 15 ). These are only rotatably attached at the base of the respective spring (not on the roller ( 16 )). This measure hardly changes the friction of the system in the normal direction of movement, but the rods ( 19 ) dampen any vibrations in all other directions. The roller ( 16 ) together with the springs ( 14, 15 ), the bars ( 19 ), the tensioning device ( 17 ) and the position sensor ( 18 ) form the dynamic control unit. The high natural frequency of the spring / mass system in the range of a few hundred Hertz should be emphasized. As a result, the damping of slow and medium frequency wire tension fluctuations is primarily achieved.

The wire ( 2 ) running off the roll ( 16 ) is guided over the pin ( 20 ), which is provided with a fast-reacting electromagnetic or piezoceramic drive and is adjustable a few millimeters in the direction ( 22 ). The wire path up to the coil ( 25 ) can be changed by setting the pin ( 20 ). If the electronics detects that a periodic voltage surge is imminent (generated by the corners of the coil), the pin ( 20 ) is briefly withdrawn by the magnet ( 21 ). As a result, a corresponding amount of wire is released and the following wire joint is absorbed. After the wire voltage surge, the pin ( 20 ) is returned to the starting position. The pin ( 20 ) with the magnet ( 21 ) form the aforementioned phase compensation unit.

The wire coming from the pin ( 20 ) is now guided over the roller ( 23 ) which is attached to the wire tension sensor ( 24 ). The wire tension sensor ( 23 ) can, for. B. in the embodiment consist of a piezoceramic element to which a deflection pin is attached. This sensor enables the determination of the absolute wire tension as well as the short-term wire voltage fluctuations.

The wire tension sensor ( 23 ) can be used to determine the correct time for deflecting the pin ( 20 ) using a suitable electronic evaluation. The parameters required for this are coil shape, wire speed and average wire tension are known to the electronic control system. However, the mechanical time constants of the magnet ( 21 ) and the pin ( 20 ) must be observed. In order to achieve a synchronization between the position of the coil ( 25 ) calculated by the electronics, a continuous evaluation of the position of the roller ( 16 ) and the wire tension on the sensor ( 23 ) is necessary. A sufficient approximation of the necessary movement of the pin ( 20 ) can then be made using the formulas of the vibration theory. The described method thus enables the wire tension control device according to the invention to be operated without electrical or mechanical coupling to the winding machine.

The wire originating from the roll ( 23 ) is fed to the coil ( 25 ) via the wire guide ( 26 ).

Claims (5)

1. Electronically controlled wire tension control device for winding round or square coils from a wire or a synthetic fiber,

• with a wire cleaning device, through which the wire originating from the wire supply is passed,
• with a wire tensioning device through which the wire originating from the wire cleaning device is guided,
• with an electronically controlled wire brake device through which the wire originating from the wire tensioning device is guided,
• with a dynamic control device through which the wire originating from the wire brake device is guided,

characterized in that:

• - In the wire cleaning unit the wire ( 2 ) is carried out between two felt disks or brushes ( 4 ) and the spring ( 6 ) continuously exerts a contact pressure on the wire. The contact pressure can optionally be varied using an additional magnet ( 5 ).
• - In the wire tensioning unit, the wire ( 2 ) receives a continuous wire tension via deflection rollers ( 9 ) on a lever / spring system ( 7, 8 ).
• - In the wire brake unit, the wire may loop several times around a roller ( 12 ) attached to a motor ( 10 ).
• - In the dynamic control unit, the wire is guided over a free or loose linearly guided roller ( 16 ) which is suspended between two or more springs and magnets ( 14, 15 ).

2. Electronically controlled wire tension control device according to claim 1 additionally with an adjustable dynamic control unit, characterized in that the base point of at least one of the springs ( 14, 15 ) in the direction of movement of the roller ( 16 ) can be changed electromechanically. 3. Electronically controlled wire tension control device according to claim 1 or 2 additionally with a phase control unit over which the wire originating from the dynamic control unit is guided, characterized in that the wire ( 2 ) is guided over an electrically adjustable roller ( 16 ) or a pin, so that the distance to the coil ( 25 ) can be varied. 4. Electronically controlled wire tension control device according to claim 3 additionally provided with a wire tension measuring device over which the wire emerging from the phase control unit is guided, characterized in that the wire is guided over a deflection pin or a deflection roller ( 23 ) which is connected to an electrical or optoelectronic train - Or pressure transducer ( 24 ) is coupled.