Closed-loop pressure control in a drafting system
The method and device for controlling drafting roller pressure in textile machines address excessive wear and load issues by optimizing pressure adjustments based on operating parameters, reducing wear and downtime.
Patent Information
- Authority / Receiving Office
- EP · EP
- Patent Type
- Patents
- Current Assignee / Owner
- TRUETZSCHLER GRP SE
- Filing Date
- 2019-09-18
- Publication Date
- 2026-07-08
AI Technical Summary
Existing methods for controlling the pressure of drafting rollers in textile machines lead to excessive wear and increased load on bearings, which are costly and require frequent adjustments, and the load on bearings is not optimized.
A method and device for controlling the pressure of drafting rollers in textile machines by acquiring operating parameters, determining and adjusting the pressure based on these parameters, and implementing a self-learning process to optimize load on the rollers.
Reduces wear on rollers and bearings, minimizes downtime, and extends the service life of the machine by optimizing pressure adjustments.
Smart Images
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Abstract
Description
[0001] The invention relates to the control of the pressure of elements of a drawing machine.
[0002] A drafting unit essentially consists of several driven lower rollers against which one or more associated upper rollers are pressed. Due to this contact force, the upper rollers are driven rotationally by the corresponding lower roller. This rotation is facilitated by a preferably elastic friction covering or lining, for example, on the upper rollers. Fiber material is also fed between the corresponding pairs of rollers. The contact force causes the fiber material to be held against the downstream arrangement of lower and upper roller(s), thus achieving the drafting process. Both the holding of the fiber material and the rotation of the associated, pressed-on roller(s) lead to wear of the covering. Excessive contact force accelerates wear. Furthermore, it increases the load on the bearings in which the rollers are freely rotatable.These must be designed accordingly, which is costly.
[0003] The purpose of the invention is to address the aforementioned disadvantages.
[0004] This problem is solved by the subject matter of the independent claim. Advantageous further developments are specified in the dependent claims.
[0005] According to the invention, a method for controlling the pressure of drafting rollers in a textile machine is provided. The method comprises a cycle. This cycle includes a first step of acquiring at least one operating parameter of the textile machine that influences the load on at least one drafting roller. Examples of operating parameters include the fiber material used, the operating speed of the drafting rollers, and climatic conditions. The cycle includes a second step. The second step is divided into several subprocesses. A first subprocess includes a first step of determining the pressure of the at least one drafting roller using the acquired operating parameter. In a second substep of this subprocess, the determined pressure is displayed.In a third step, a user can, for example, adjust the pressure on at least one of the drafting unit's upper rolls via a touchscreen. Alternatively or additionally to the first step, a second step is provided. This second step includes a fourth step: determining whether the detected operating parameter lies within a predetermined range or exceeds or falls below a predetermined threshold. If it is determined that the detected operating parameter lies outside the range or exceeds or falls below the threshold, the second step includes a fifth step: adjusting the pressure on the drafting unit's upper roll in such a way that the predetermined operating parameter is expected to fall within the range or reach, fall below, or exceed the threshold. This is an automated pressure adjustment.As a result, the load on the drafting rollers can be optimized, thus reducing wear.
[0006] According to the invention, the method further comprises an initial step of determining the range or threshold value before the execution of said cycle. Before the drawing machine, for example, begins to operate, these values are determined and used as the basis for the aforementioned control.
[0007] The initial step preferably comprises a step of enabling the input of the range or threshold value, and / or a step of determining the range or threshold value based on the processing speed of the textile machine and the fiber material currently being processed. In particular, the latter step allows the drafting unit to be restarted very quickly after a batch change; downtime is reduced.
[0008] The determination step is preferably carried out by reading a database in which at least the speed data, fiber material-defining data, and the pressure of the drafting unit's upper roll are correlated. The database thus represents a knowledge base for the drafting unit control, so that the necessary inputs only need to be entered once.
[0009] Preferably, each of the aforementioned methods is designed as a self-learning process. Supervised learning is advantageous in this context and can, for example, be implemented by the manufacturer of a newly designed drafting machine. This has the advantage that, ideally, the drafting machine is immediately ready for use by the customer without requiring any adjustments.
[0010] The aforementioned cycle is preferably repeated at regular intervals. This may be due to the fact that climatic conditions are repetitive in the morning and change throughout the day, necessitating adjustments to the printing roller settings. Alternatively or additionally, this cycle is executed when a predetermined condition is present.
[0011] Such a condition may involve changing the fiber material to be stretched or a roller, or restarting the drawing machine or textile machine.
[0012] In each of the aforementioned methods, the cycle can be executed multiple times, depending on the number of drafting unit top rolls to be monitored, and / or it can be based on the pressure of several drafting unit top rolls. In the first case, in extreme cases, the pressure is set individually for each lower roll. In the second case, the pressure is set for several, or in extreme cases, all lower rolls with the same pressure setting.
[0013] The operating parameters specified above preferably include technological output parameters of the drafting unit or the textile machine and / or load data of at least one drive motor of one of the drafting unit's lower rolls belonging to the at least one upper drafting unit roll. That is, data that can be easily determined by sensors is sufficient to implement the pressure control.
[0014] Each of the aforementioned methods is preferably designed as a computer-implemented method. The method can thus be provided, for example, as a firmware update, so that existing textile machines can also be retrofitted with the pressure control according to the invention.
[0015] The invention relates to a drafting device with a pressure drive section, comprising, for example, at least one pneumatic cylinder, and at least one drafting unit. This drafting unit is provided with a plurality of drafting unit lower rollers, a plurality of drafting unit upper rollers, and a plurality of pressure arms. The pressure arms are coupled to the pressure drive section in such a way that the pressure drive section is able to press a corresponding drafting unit upper roller against a corresponding drafting unit lower roller via the pressure arms. Furthermore, the drafting device includes a control unit or is coupled to one, for example, via a bus. The control unit is configured to execute one of the aforementioned methods for at least one drafting unit upper roller by means of at least one pressure drive section. That is to say, the invention is universally applicable.
[0016] A textile machine according to the invention has such a drafting device. The pressure drive section comprises a pressure regulator which is connected between a pneumatic drive for the at least one drafting upper roller and the pressure arm belonging to the at least one drafting upper roller. Diaphragm control valves, for example, are suitable as pressure regulators.
[0017] The textile machine is preferably configured as a stretcher, tape winder, combing machine, flyer or spinning machine.
[0018] Further features and advantages of the invention will become apparent from the following description of preferred embodiments. These show: Figure 1 shows a stretching arrangement, Figure 2 shows the stretching section of Figure 1 In greater detail, Figure 3 shows a control according to one embodiment of the invention and Figure 4 shows a control according to another embodiment of the invention.
[0019] Figure 1Figure 1 shows an arrangement 1 with a gate 2 and a downstream section 100 in a typical arrangement.
[0020] Gate 2 is constructed in a known manner and will not be described further.
[0021] The section 100 includes, among other things, a can storage device 110 at its outlet. In the example shown, the can storage device 110 comprises a can rail 111 for the full cans and a preferably driven can track 112, which moves empty cans into the actual can changer. The can changer includes, for example, a can slide 113 in a known manner. A control platform 102 is located to the side of the section 100. An operating terminal 101 is located at one end of the control platform 102. Furthermore, a stretching unit cover 103 is visible, which covers a stretching section 120 in a known manner.
[0022] Figure 2 shows section 120 of Figure 1In greater detail. The stretching section 120 is designed as an example of a 4-over-3 stretching unit. That is, the stretching section 120 has four upper rollers 125-128 (only upper rollers 125 and 126 are visible). The upper roller 125 is pressed against the corresponding lower roller 129 by means of pressure pistons 134, 135 via bearings 132, 133, in which the upper roller 125 is mounted so as to rotate freely.
[0023] The upper roller 126 is accordingly pressed against the corresponding lower roller 130. The upper rollers 127, 128, which are not visible here, are pressed against the lower roller 131 by means of the pressure arms 123, 124.
[0024] Pneumatic lines 139 are visible on the left side, through which compressed air is directed to the pressure arms 121-124. Alternatively, the pressure is directed only to the two front pressure arms 121 and 122.
[0025] Furthermore, sensor lines 140 are visible, which lead into the respective pressure arms 121-124. Pressure sensors or sensors that can determine the extension position of the associated upper roller 125-128 are arranged in the pressure arms 121-124.
[0026] Furthermore, pressure bars 136 - 138 are visible, which are also pressed against a respective upper roller 125 - 127 in order to reduce or even avoid winding.
[0027] Figure 3 shows a regulation for the in Figure 2 The stretching section 120 shown. According to the embodiment shown here, a single pressure regulator 141 is provided, which acts directly on each upper roller 125-128 via pneumatic lines 139. It is clear that this is only schematic. In reality, the pressure regulator 141 is coupled to respective pressure cylinders, which press on the respective bearings 132, 133 of the associated upper roller 125 via associated pistons 134, 135.
[0028] Initial settings are input to the pressure regulator 141 via a coupling or data connection 143. According to the invention, these settings depend on the fiber material. Different settings are input to the pressure regulator 141 depending on the coefficient of friction and the drafting unit setting.
[0029] A sensor device 142, which, for example, detects the Figure 2The pressure regulator 141 receives values from the sensors shown, which influence the pressure applied by the upper rollers 125-128 to the corresponding lower rollers 129-131. Such sensor values could, for example, be the maximum extension position of the respective upper roller 125-128. If, for instance, the covering of the corresponding lower roller 129-131 is somewhat worn, the resistance of this elastic covering is lower, so the pressure regulator 141 applies a lower pressure to the corresponding upper roller 129-131 than if the covering were new. This makes it possible to reduce the wear of the covering of the corresponding lower roller 129-131, resulting in longer service life.
[0030] Figure 4Figure 1 shows a control system according to another embodiment of the invention. As can be seen, each lower roller 129-131 and its associated upper roller 120-128 is assigned its own pressure regulator 141. Since the upper rollers 145-128 are generally provided with the same covering, the pressure regulators 141 are accordingly given the same setpoint values via the respective coupling 143.
[0031] Because each pressure regulator 141 is coupled to its own sensor unit 142 via sensor lines 140, each pressure regulator 141 can individually set an optimal pressure for the respective lower roller 129-131 or the associated upper rollers 125-128. Since the upper rollers 127 and 128 are pressed against the same lower roller 131, the example shown provides for both upper rollers 127 and 128 to be actuated by a single pressure regulator 141. However, it is also possible, of course, to assign a separate pressure regulator 141 to each upper roller 127 and 128.
[0032] The invention enables, by means of the illustrated control system, a method for regulating the pressure of drafting unit upper rolls 125-128 against associated lower rolls 129-131 of the drafting section 120. In a first step, at least one operating parameter influencing the load on at least one drafting unit upper roll 125-128 is recorded. Such an operating parameter can take into account the fiber material to be processed, the rotational speed of the respective drafting unit lower roll 129-131, and the ratio of this rotational speed to the rotational speed of a lower roll 130, 131 located directly upstream in the fiber strip transport direction.
[0033] In the first subprocess of a second step of this procedure, the pressure of the respective drafting unit top roller 125-128 is determined using at least one recorded operating parameter. For example, if it is detected that the covering of the respective drafting unit top roller 125-128 is somewhat worn, the pressure is automatically reduced, for example, based on a database. Preferably, the determined pressure is displayed to a user in this subprocess.
[0034] In a third step of this subprocess, the user is given the opportunity to further adjust the pressure. This makes it possible, for example, to modify the automatically determined values based on experience. The determined values thus serve as a kind of suggestion and facilitate the operation of stretching section 120. This allows even a less experienced user to operate stretching section 120.
[0035] Alternatively or additionally to this subprocess, a second subprocess may be provided. This subprocess involves determining whether the measured operating parameter lies within a predetermined range. This can be achieved using a standard threshold analysis. If the operating parameter is outside this range, or if a predetermined threshold is not reached, fallen below, or exceeded in a permissible manner, the pressure on the associated upper roll of the stretching unit 125-128 is adjusted so that it can be assumed that the predetermined operating parameter will fall within the desired range, or that the threshold analysis will yield a positive result. This procedure thus approximates the pressure to the pressure required for the smooth operation of the stretching section 120. This also prevents sudden pressure changes, which can have a negative impact during stretching.
[0036] Preferably, the range or threshold is initially determined in a first step. This determination can, for example, involve reading a database. However, it is also possible to allow the range or threshold to be entered manually.
[0037] The procedure can also be set up to be self-learning. This means that the stretching section 120 automatically adjusts the pressure in a test run, and the associated pressure regulator 141 is preferably trained in the procedure so that it adjusts automatically according to a standard learning procedure.
[0038] The aforementioned process steps constitute a cycle according to the invention, which can be repeated. Repetition can occur at regular intervals, for example once an hour, or when a predetermined condition is present. This condition can mean a change of the fiber material to be drawn, a change of a roller, and / or the (re-)starting of the drawing section 120 or the section 100.
[0039] Preferably, the cycle is executed multiple times according to the number of drafting unit top rolls 125-128 to be monitored, i.e., up to four times in the case of the drafting unit 120 described. If the cycle refers to several drafting unit top rolls 127, 128 simultaneously, as shown below right in Figure 4 As shown, the cycle is executed three times, for example.
[0040] The aforementioned operating parameters can include technological output parameters of the stretching section 120 or the section 100. Furthermore, load data of a drive motor (e.g., its temperature) can be incorporated to prevent overloading of the drive of stretching section 120. This allows the stretching section 120 to be slowed down, thereby reducing its output, but preventing damage to the stretching section 120 and thus a failure.
[0041] Preferably, the method according to the invention is implemented by computer.
[0042] The invention is not limited to the prescribed embodiments.
[0043] The invention can be applied to any type of drawing section. This includes, for example, drawing units on tape winders, combing machines, flyers, and spinning machines.
[0044] Furthermore, other groups of upper rollers 125 - 128 can also be assigned to a single pressure regulator 141.
[0045] The stretching section 120 can also be designed differently, i.e., it can include a different number of upper and / or lower rollers.
[0046] As a result, the invention provides a very simple and universally applicable way to optimally adjust the pressure of drafting unit top rollers 125-128 and thus improve the service life of drafting unit top rollers 125-128n and thus the entire machine. Reference symbol list
[0047] 1. Stretching arrangement 2. Gates 100Distance 101Control terminal 102Platform 103Drawing system hood 110 Can holder 111 Can rail 112 Can track 113 Can slider 120 Stretch section 121 - 124 Pressure arm 125 - 128 Upper roller 129 - 131 Lower roller 132, 133 Bearing 134, 135 Piston 136 - 138 Pressure rod 139 Pneumatic line 140 Sensor line 141 Pressure regulator 142 Sensor device 143 Coupling
Claims
1. Textile machine (100) comprising a drawing device (120) • comprising - a pressure drive section (139; 132, 133; 134, 135; 141) and - at least one drawing unit comprising · a plurality of bottom rollers, · a plurality of top rollers (125-128) and · a plurality of pressure arms (121-124) which are coupled to the pressure drive section (139; 132, 133; 134, 135; 141) in such a way that the pressure drive section (139; 132, 133; 134, 135; 141) is capable of forcing, via the pressure arms (121-124), a respective one of the top rollers (125-128) against a corresponding bottom roller (129-131), and • comprising or coupled to a control system (141) configured to carry out a method for regulating the pressure of top rollers (125-128) of the textile machine (100) by means of at least one pressure drive section (139; 132, 133; 134, 135; 141) for at least one top roller (125-128), • wherein the pressure drive section (139; 132, 133; 134, 135; 141) comprises a pressure controller (141) which is connected between a pneumatic drive for the at least one top roller (125-128) and the pressure arm (121-124) associated with the at least one top roller (125-128), characterised in • that each pressure controller (141) is coupled via sensor lines (140) to its own sensor system (142), via which values are input to the pressure controller (141) that influence the setting of the pressure from the top rollers (125-128) onto the associated bottom roller (129-131) and that the method comprises a cycle comprising • a first step of detecting at least one operating parameter of the textile machine (100) influencing the load on at least one top roller (125-128), and • a second step comprising - a first sub-process including · a first sub-step of determining the pressure of the at least one top roller (125-128) by means of the detected operating parameter, · a second sub-step of displaying the determined pressure, and · a third sub-step of enabling a user to alter the pressure on the at least one top roller (125-128), and - a second sub-process including · a fourth sub-step of determining whether the detected operating parameter lies within a predetermined range or falls below or exceeds a predetermined threshold value, and · if it has been determined that the detected operating parameter lies outside the range or exceeds or falls below the threshold value, a fifth sub-step of changing the pressure at the top roller (125-128) in such a way that the operating parameter is expected to enter the range or reach, exceed or fall below the threshold value, and • furthermore, prior to executing the cycle, comprises an initial step of determining the range or threshold value.
2. A textile machine (100) according to claim 1, wherein the initial step comprises • a step of allowing the range or threshold value to be entered, and / or • a step of determining the range or threshold value based on - a processing speed of the textile machine (100) and - a fibre material currently being processed.
3. Textile machine (100) according to claim 2, wherein the determination step is carried out by reading from a database in which at least speed data, data defining the fibre material and data defining the pressure of the draw frame top roll (125-128) are associated with one another.
4. Textile machine (100) according to one of the preceding claims, wherein the method is designed as a self-learning method.
5. Textile machine (100) according to one of the preceding claims, wherein the cycle • is repeated at regular intervals and / or • is executed upon the occurrence of a predetermined condition.
6. A textile machine (100) as claimed in claim 5, wherein the condition comprises • a change in the fibre material to be drawn, • the change of a roller and / or • a (re)start of the drawing unit or the textile machine (100).
7. Textile machine (100) according to one of the preceding claims, wherein the one cycle • is performed multiple times in accordance with the number of top rollers (125-128) to be monitored and / or • relates to the pressure of several top rollers (125-128).
8. Textile machine (100) according to one of the preceding claims, wherein the at least one operating parameter comprises • initial process parameters of the drawing unit or the textile machine (100) and / or • load data of at least one drive motor of a bottom roller (129-131) associated with the at least one top roller (125-128).
9. Textile machine (100) according to one of the preceding claims, wherein the method is configured as a computer-implemented method.
10. Textile machine (100) according to one of the preceding claims, configured as • draw frame (100), • a lap winder, • combing machine, • a flyer or • spinning machine.