JP5955738B2 - Tension detector - Google Patents

Description

  The present invention relates to a tension detection device that detects the tension of a yarn.

  A tension detecting device that detects the tension of a yarn is used, for example, in a false twisting machine that performs false twisting on a yarn. The tension detection device described in Patent Literature 1 includes a movable member that is displaced according to the tension of the traveling yarn, a magnet attached to the movable member, and a Hall element provided at a predetermined position facing the magnet. ing. In this tension detection device, the magnet attached to the movable member is displaced in accordance with fluctuations in yarn tension, and the strength of the magnetic field around the Hall element changes. This change in the strength of the magnetic field is detected by a Hall element, and the tension of the yarn is detected from the strength of the magnetic field.

JP-A-61-212738

  In general, a magnet has a property that the strength of a magnetic field generated in the surroundings varies depending on a temperature change. For example, when a magnet is heated, the strength of the magnetic field generated around it decreases. In the tension detection device described in Patent Document 1, frictional heat is generated by the thread that contacts the movable member, and the generated frictional heat is transmitted to the magnet via the movable member. For this reason, in the tension detection apparatus described in Patent Document 1, the strength of the magnetic field of the magnet decreases due to heat. When the strength of the magnetic field generated by the magnet around changes due to temperature change, the strength of the magnetic field around the Hall element also changes, and the tension detection value fluctuates. On the other hand, the frictional heat due to the contact between the yarn and the movable member varies depending on the characteristics of the oil applied to the yarn, the production speed, the material and shape of the yarn, and the difference in fineness. It is not possible to correct for fluctuations in height. As described above, the tension detection device described in Patent Document 1 has a problem that it is impossible to detect the accurate yarn tension due to a temperature change of the magnet.

  An object of the present invention is to make it possible to accurately detect the tension of a yarn even when the strength of a magnetic field of a magnet varies due to a temperature change.

A tension detection device according to a first aspect of the present invention is a movable member that contacts a traveling yarn and is displaced according to the tension of the yarn, a magnet attached to the movable member, and a magnetic field of the magnet provided at a predetermined position. Detecting means for detecting the strength of the magnet, further comprising a correcting means for correcting fluctuations in the strength of the magnetic field of the magnet due to a temperature change , the correcting means being accompanied by a temperature rise. The magnet is displaced in a direction approaching the detection means .

In the present invention, the correction means corrects fluctuations in the magnetic field strength of the magnet due to temperature changes. Therefore, for example, even if the strength of the magnetic field of the magnet is reduced due to frictional heat or the like caused by the thread contacting the movable member, the correction means corrects the reduction in the strength of the magnetic field. For this reason, even if there is a fluctuation in the magnetic field strength of the magnet due to a temperature change, the yarn tension can be detected accurately.
Further, in the present invention, the magnet is displaced in the direction approaching the detecting means as the temperature rises by the correcting means. Therefore, even if the strength of the magnetic field of the magnet decreases due to frictional heat or the like caused by the thread that contacts the movable member, the magnetic field with respect to the detecting means decreases as the magnet approaches the detecting means as the temperature rises. It is corrected. For this reason, even if the magnetic field strength of the magnet is reduced by heat, the tension of the yarn can be accurately detected.

A tension detection device according to a second aspect of the present invention is the tension detection device according to the first aspect , wherein the correction means is a member that is provided between the movable member and the magnet and expands as the temperature rises. The magnet is displaced in a direction approaching the detection means due to expansion accompanying a temperature rise.

  In the present invention, the correcting means is provided between the movable member and the magnet, and the magnet is displaced in a direction approaching the detecting means due to expansion of the correcting means accompanying a rise in temperature. Therefore, by expanding the correction means using frictional heat generated by the thread that contacts the movable member, the magnet is displaced in a direction approaching the detection means with a simple configuration, and the decrease in the strength of the magnetic field of the magnet is corrected. be able to.

A tension detection device according to a third aspect of the present invention is the tension detection device according to the first or second aspect , wherein the correction means is a member having a heat insulating property.

  In the present invention, the correction means provided between the movable member and the magnet is a member having heat insulation properties. Accordingly, it is possible to suppress the frictional heat generated by the thread that contacts the movable member from being transmitted to the magnet. For this reason, since the decrease in the strength of the magnetic field of the magnet due to heat is suppressed, the correction amount of the decrease in the strength of the magnetic field of the magnet by the correction means can be suppressed to a small level, and the accuracy of detecting the yarn tension further increases. .

A tension detection device according to a fourth aspect of the present invention is the tension detection device according to any one of the first to third aspects, wherein the movable member is configured to contact the traveling yarn and the yarn against the contact portion. And a recessed portion in which the yarn travels in the internal space.

  In the present invention, the movable member is provided at at least one position before and after the traveling direction of the yarn with respect to the contact portion, and has a recess in which the yarn travels in the internal space. Therefore, the movable member is cooled by the accompanying flow caused by the yarn traveling in the recess. For this reason, a decrease in the strength of the magnetic field of the magnet due to heat is suppressed.

  In the present invention, the correction means corrects fluctuations in the magnetic field strength of the magnet due to temperature changes. Therefore, for example, even if the strength of the magnetic field of the magnet is reduced due to frictional heat or the like caused by the thread contacting the movable member, the correction means corrects the reduction in the strength of the magnetic field. For this reason, the tension of the yarn can be accurately detected even when there is an influence of fluctuations in the magnetic field strength of the magnet due to temperature changes.

It is a schematic front view of the false twist processing machine concerning this embodiment. It is a schematic front view of a tension sensor. It is a schematic perspective view of a tension sensor. It is a schematic front view of the tension sensor which concerns on a modification. It is a block diagram which shows roughly the electrical structure of a false twist processing machine provided with the tension sensor which concerns on a modification.

  Hereinafter, embodiments of the present invention will be described. In the present embodiment, an embodiment in which the tension detection device of the present invention is used in a false twisting machine that performs false twisting on yarn will be described. FIG. 1 is a schematic front view showing a false twisting machine according to the present embodiment. The false twisting machine 1 is, for example, for applying a twist to thermoplastic synthetic fibers such as polyester and polyamide to impart shrinkage to produce a processed yarn rich in elasticity.

  As shown in FIG. 1, the false twisting machine 1 includes a main machine base 2, two winding bases 3, a support portion 4, and the like, and each device described later is disposed thereon. The main machine base 2 extends in the vertical direction. The two take-up stands 3 are arranged opposite to the main machine stand 2 with a work space 6 in a symmetrical position across the main machine stand 2. On the side opposite to the work space 6 of the take-up stand 3, there is a space 7 in which the operator picks up a fully wound package P that has been taken up by a take-up device 13 provided later on the take-up stand 3. To do. The support unit 4 connects the main machine base 2 and the two winding stands 3.

  The false twisting machine 1 includes two yarn feeding creels 11 disposed opposite to the two winding bases 3 across the space 7, two false twisting apparatuses 12 provided on the upper part of the main machine base 2, and two windings. A take-up device 13 provided on the take-up table 3 is provided. The yarn feeding creel 11 holds the yarn feeding package S and feeds the yarn Y of the yarn feeding package S. The false twisting device 12 false twists the yarn Y supplied from the yarn feeding creel 11. The winding device 13 winds the yarn Y falsely twisted by the false twisting device 12 to form a package P. The winding device 13 is arranged in three stages in the vertical direction.

  In the yarn path from the yarn feeding creel 11 to the winding device 13, a first feed roller 14, a first heating device 17, a cooling device 19, a false twisting device 12, a second feed roller 15, A second heating device 18 and a third feed roller 16 are arranged. A plurality of these devices are arranged side by side in the direction perpendicular to the plane of FIG. That is, in the false twisting machine 1, each device along the yarn path from the yarn feeding creel 11 to the winding device 13 is arranged symmetrically across the main machine base 2, and the paper surface of FIG. A plurality are arranged side by side in the vertical direction. A first yarn guide 20 to a fourth yarn guide 23 for changing the yarn path of the yarn Y are provided on the yarn path from the yarn feeding creel 11 to the winding device 13.

  The first feed roller 14 is disposed at the upper end portion of the winding table 3. The first heating device 17 is disposed above the work space 6. The cooling device 19 is disposed closer to the main machine base 2 than the first heating device 17 above the work space 6. The second feed roller 15 is disposed below the false twisting device 12 of the main machine base 2. The second heating device 18 is disposed below the second feed roller 15 of the main machine base 2. The first heating device 17 and the cooling device 19 are arranged substantially linearly along the horizontal direction above the work space 6, and the yarn path from the yarn feeding creel 11 to the winding device 13 is the work space 6. Is formed so as to surround. The 1st heating apparatus 17 and the cooling device 19 are connected to the support part 4, and the position is being fixed. In the work space 6, an operator can get on a work carriage for threading (not shown), perform threading at a high position near the first heating device 17 and the cooling device 19, and perform maintenance. Become.

  The first to third feed rollers 14 to 16 are rollers for feeding the yarn Y from the upstream side to the downstream side in the yarn traveling direction. Each yarn feed speed is set so that the yarn feed speed of the second feed roller 15 is faster than the yarn feed speed of the first feed roller 14. For this reason, the yarn Y is stretched between the first feed roller 14 and the second feed roller 15. Each yarn feed speed is set so that the yarn feed speed of the third feed roller 16 is slower than the yarn feed speed of the second feed roller 15. For this reason, the yarn Y is subjected to a relaxation heat treatment between the second feed roller 15 and the third feed roller 16.

  Here, the operation of the false twisting machine 1 until the yarn Y fed from the yarn feeding creel 11 is wound up by the winding device 13 will be described. The yarn Y drawn between the first feed roller 14 and the second feed roller 15 is twisted by the false twisting device 12. The false twisting device 12 is, for example, a belt-type nip twister, and twists and feeds the yarn Y with the yarn Y traveling between a pair of belts crossing each other. The twist formed by the false twisting device 12 propagates to the first feed roller 14, and the yarn Y twisted while being drawn is heat-fixed by the first heating device 17 and then cooled by the cooling device 19. The The twisted and heat-fixed yarn Y is untwisted before reaching the second feed roller 15 after passing through the false twisting device 12. The yarn Y thus stretched and false twisted is subjected to relaxation heat treatment by the second heating device 18 and wound around the paper tube by the winding device 13 to form the package P.

  The second yarn guide 21 in which the yarn Y travels immediately after traveling through the false twisting device 12 constitutes a part of a tension sensor 51 (tension detection device) that detects the tension of the yarn Y shown in FIGS. 2 and 3. Yes. That is, in the false twisting machine 1, the tension sensor 51 detects the tension of the yarn Y immediately after false twisting in order to confirm the tension of the yarn Y immediately after false twist. Thereby, the quality of the yarn Y immediately after twisting can be confirmed. Hereinafter, the tension sensor 51 will be described.

  FIG. 2 is a schematic front view showing the tension sensor. FIG. 3 is a schematic perspective view showing the tension sensor. As shown in FIGS. 2 and 3, the tension sensor 51 includes a leaf spring (movable member) 52, a magnet 53, a Hall element (detection means) 54, an expansion member 55 (correction means), and the like. The leaf spring 51 is in contact with the traveling yarn Y and is displaced according to the tension of the yarn Y. The leaf spring 51 is formed in a substantially rectangular shape. One end of the leaf spring 52 in the longitudinal direction is fixed to the main machine base 2 with a bolt 56 and extends in a substantially horizontal direction. The leaf spring 52 is provided with a second thread guide 21 (contact portion) on the surface of the other end portion in the longitudinal direction. The traveling yarn Y comes into contact with the second yarn guide 21 and the yarn path is changed. A concave portion 57 is provided at the other end of the leaf spring 52 in the longitudinal direction. The yarn Y that has contacted the second yarn guide 21 travels in the internal space of the recess 57. Accordingly, the recess 57 is provided at a position behind the second yarn guide 21 in the traveling direction of the yarn Y.

  The magnet 53 is attached to the leaf spring 52. Specifically, the magnet 53 is attached to the back surface of the other end portion in the longitudinal direction of the leaf spring 52 via an expansion member 55 described later. The magnet 53 is formed in a substantially cylindrical shape. The hall element 54 is provided at a predetermined position facing the magnet 53. The hall element 54 detects the strength of the magnetic field of the magnet 53. The hall element 54 is driven by a constant current drive circuit (not shown), and outputs a voltage value corresponding to a magnetic field applied from the magnet 53, that is, a magnetic flux density interlinked with itself, thereby generating a magnetic field of the magnet 53. It is to detect strength. The voltage value detected by the Hall element 54 is amplified to an appropriate value and A / D converted. The tension of the yarn Y is detected based on the A / D converted digital value.

  In the tension sensor 51 described above, when the tension of the yarn Y fluctuates (increases), the leaf spring 52 bends (displaces) downward with one end (on the main machine base 3 side) as a fulcrum. At this time, the magnet 53 provided at the other end of the leaf spring 52 moves (displaces) obliquely downward. As the magnet 53 moves, the distance between the magnet 53 and the Hall element 54 approaches, so that the magnetic flux density linked to the Hall element 54 changes (increases). When the magnetic flux density linked to the Hall element 54 changes, the voltage value output from the Hall element 54 also changes (increases). Based on the changed voltage value, the tension of the yarn Y is detected.

  Here, in general, when a magnet is heated, the strength of the magnetic field generated around it decreases. Therefore, the strength of the magnetic field of the magnet 53 attached to the leaf spring 52 via the expansion member 55 is also reduced by the frictional heat generated by the yarn Y that contacts the second yarn guide 21 of the leaf spring 52. Therefore, the tension sensor 51 of the present invention includes an expansion member 55.

  The expansion member 55 is provided between the leaf spring 52 and the magnet 53 on the back surface of the other end portion in the longitudinal direction of the leaf spring 52. The expansion member 55 is made of a heat resistant resin, and is a member that expands as the temperature rises. Therefore, since the expansion member 55 expands in the direction of arrow A (see FIG. 2) as the temperature rises, the magnet 53 is displaced in the direction approaching the Hall element 54 (direction of arrow A) as the temperature rises. As a result, even if the strength of the magnetic field of the magnet 53 decreases due to frictional heat or the like caused by the thread Y that contacts the second thread guide 21 of the leaf spring 52, the magnet 53 approaches the Hall element 54 as the temperature rises. Thus, the decrease in the magnetic field strength with respect to the Hall element 54 is corrected. That is, the expansion member 55 corrects so that the fluctuation of the magnetic field strength with respect to the Hall element 54 becomes smaller as the temperature rises. For this reason, the tension of the yarn Y can be accurately detected even if the strength of the magnetic field of the magnet 53 is reduced by heat. Further, since the expansion member 55 is expanded using frictional heat generated by the yarn Y contacting the second yarn guide 21 of the leaf spring 52 and the magnet 53 is displaced in a direction approaching the Hall element 54, the configuration is simple. The decrease in the magnetic field strength of the magnet 53 can be corrected. In addition, by appropriately selecting the material (linear expansion coefficient) that forms the expansion member 55 and the size of the expansion member 55 (the length in the direction of arrow A), the magnetic field strength of the magnet 53 is appropriately corrected. can do.

  The expansion member 55 is a heat-resistant resin and is a member having heat insulation properties. Accordingly, the frictional heat generated by the yarn Y that contacts the second yarn guide 21 of the leaf spring 52 is suppressed from being transmitted to the magnet 53. For this reason, a decrease in the strength of the magnetic field of the magnet 53 due to heat is suppressed. In addition, since the expansion of the magnetic field of the magnet 53 is corrected by the expansion member 55, the detection accuracy of the tension of the yarn Y is further increased.

  The leaf spring 52 is provided at a position behind the second yarn guide 21 in the running direction of the yarn Y, and has a recess 57 in which the yarn Y runs in the internal space. Accordingly, the leaf spring 52 is cooled by the accompanying flow caused by the yarn Y traveling in the recess 57. For this reason, a decrease in the strength of the magnetic field of the magnet 53 due to heat is suppressed.

Next, a specific example of the tension sensor 51 will be described. In this embodiment, a heat-resistant resin having a linear expansion coefficient of 3.5 × 10 ⁻⁵ is used as the expansion member 55, and a polyester processed yarn of 165 dtex / 288 f is used as the yarn Y. Table 1 shows the results of measuring the temperature rise of the expansion member 55 and the magnet 53 when the yarn Y is run by the tension sensor 51.

As shown in Table 1, it can be seen that the temperature of the magnet 53 rises as the yarn Y travels in contact with the second yarn guide 21. The decrease in the magnetic force of the magnet 53 due to this temperature rise is as shown in Table 2.

As shown in Table 2, when there is a decrease in the magnetic force of 0.077 to 0.093 mT, the detected tension of the yarn Y causes an error of 1.5 to 1.8 cN, and the accurate yarn Y The tension cannot be detected. In the present invention, the decrease in the strength of the magnetic field of the magnet 53 is corrected by the displacement of the magnet 53 in the direction approaching the Hall element 54 by the expansion member 55 as the temperature rises, and accurate tension detection is possible. It becomes. Here, the amount of change in length due to the temperature change of the expansion member 55 is ΔL, the temperature of the expansion member 55 is St, the room temperature is Rt, and the linear expansion coefficient (3.5 × 10 ⁻⁵ ) of the expansion member 55 is γ, Assuming that the length of the expansion member 55 is L, the following relationship is established between them.
ΔL = (St−Rt) * γ * L (1)

When the distance between the magnet 53 and the hall element 54 is x, the relationship between the distance x and the magnetic force (magnetic flux density) B applied to the hall element 54 is as follows. It is approximated by the following linear expression between 1 and 3.0 mm.
B = −70 / 4 * x + 70
Here, when the change amount of the distance x is Δx and the change amount of the magnetic force B is ΔB, the relationship of the following equation is established.
ΔB = −70 / 4 * Δx (2)
That is, when the distance increases by one unit (the magnet 53 moves away from the Hall element 54), the magnetic force decreases by 70/4. On the contrary, when the distance decreases by 1 unit (the magnet 53 approaches the Hall element 54), the magnetic force increases by 70/4.

Here, an appropriate change amount Δx of the distance x between the magnet 53 and the Hall element 54 for properly correcting the magnetic force drop in Table 2 is obtained from the equation (2), and this value is calculated by the temperature of the equation (1). An appropriate length L of the inflatable member 55 can be obtained by substituting the length change amount ΔL for calculation. When the speed of the yarn Y is 800 m / min, the temperature rise of the magnet 53 is 10.5 ° C., and the magnetic force drop of the magnet 53 is 0.077 mT. Therefore, from Equation (2), the appropriate change amount Δx is 0.0044 mm. When this value is substituted for ΔL in equation (2) and calculated, the length L of the expansion member 55 is 3.2 mm. When the yarn speed is 1000 m / min, the temperature increase of the magnet 53 is 12.6 ° C., and the magnetic force decrease of the magnet 53 is 0.093 mT. Therefore, the appropriate change amount Δx is 0.0053 mm from the equation (2). When this value is calculated by substituting ΔL in equation (2), the length L of the expansion member 55 is 3.0 mm. Therefore, for example, when the linear expansion coefficient of the expansion member 55 is 3.5 × 10 ⁻⁵ , the reduction in the strength of the magnetic field of the magnet 53 can be appropriately achieved by setting the length of the expansion member 55 to 3.0 mm. It can be corrected.

  As described above, appropriate correction can be performed by appropriately selecting the material (linear expansion coefficient) that forms the expansion member 55 and the size of the expansion member 55 (length in the direction of arrow A). Even when the polyester processed yarn of 165 dtex / 288f is run at a speed of 800 to 1000 m / min, it is possible to suppress an error in the tension detection value due to a decrease in the magnetic force of the magnet 53 to about 0.02 cN or less.

  The embodiment of the present invention has been described above. However, the form to which the present invention can be applied is not limited to the above-described embodiment, and may be changed as appropriate without departing from the spirit of the present invention, as exemplified below. Can be added.

  FIG. 4 is a schematic front view of a tension sensor 51 according to a modification. Unlike the embodiment described above, the tension sensor 51 according to the modification does not include the expansion member 55. In this modification, a temperature sensor 71 that detects the temperature of the magnet 53 is provided. FIG. 5 is a block diagram schematically showing an electrical configuration of the false twisting machine 1 including the tension sensor 51 according to the second modification. The false twisting machine 1 includes a control device 73 that controls each part of the false twisting machine 1. Further, the tension sensor 51 includes a correction circuit 72. The correction circuit 72 corrects fluctuations in the magnetic field strength (voltage value) detected by the Hall element 54 based on the temperature of the magnet 53 detected by the temperature sensor 71 and detects the tension of the yarn Y. That is, the strength (voltage value) of the magnetic field detected by the Hall element 54 is largely corrected so as to correct the decrease in the magnetic field strength of the magnet 53 as the temperature rises, and the tension of the yarn Y is detected. . Then, the correction circuit 72 outputs the detected tension of the yarn Y to the control device 73. The control device 73 controls each part based on the tension of the yarn Y. In this modification, the correction circuit 72 that corrects the fluctuation of the magnetic field strength of the magnet 53 is provided. However, the correction may be performed by the control device 73.

  In the embodiment described above, a decrease in the strength of the magnetic field of the magnet 53 due to a temperature rise is corrected. Not only this but the fluctuation | variation of the magnetic field intensity of the magnet 53 by a temperature change should just be correct | amended. For example, when the strength of the magnetic field of the magnet 53 increases due to a temperature change, the magnet 53 is displaced in a direction away from the Hall element 54, so that the increase in the strength of the magnetic field of the magnet 53 is corrected. When the strength of the magnetic field 53 is decreased, the decrease in the strength of the magnetic field of the magnet 53 may be corrected by displacing the magnet 53 in a direction approaching the Hall element 54. In this way, the tension of the yarn Y can be detected even if the strength of the magnetic field of the magnet 53 varies due to temperature changes.

  In the above-described embodiment, the magnet 53 is displaced in the direction approaching the Hall element 54 as the temperature rises, so that the decrease in the magnetic field strength of the magnet 53 is corrected. Not only this but the fall of the strength of the magnetic field of magnet 53 should just be corrected with temperature rise. For example, the decrease in the strength of the magnetic field of the magnet 53 may be corrected by displacing the Hall element 54 in a direction approaching the magnet 53 as the temperature rises.

  In the above-described embodiment, the expansion member 55 causes the magnet 53 to be displaced in a direction approaching the Hall element 54 as the temperature rises. Not limited to this, instead of the expansion member 55 that utilizes the change in length due to thermal expansion, for example, by using a structure in which materials having different linear expansion coefficients are bonded together, the shape changes as the temperature rises. Thus, the distance between the magnet 53 and the Hall element 54 can be reduced.

  In the above-described embodiment, the magnetic field strength of the magnet 53 is detected using the Hall element 54. However, the magnetic field strength of the magnet 53 may be detected using a magnetic sensor other than the Hall element 54.

  In the above-described embodiment, the recessed portion 57 is provided at a position behind the second yarn guide 21 in the traveling direction of the yarn Y. Not only this but the recessed part 57 is provided in the at least any one position (front, back, front, back) of the 2nd thread guide 21 in the front-back direction of the thread | yarn Y. Just do it.

  In the above-described embodiment, the embodiment in which the tension sensor 51 is used in the false twisting machine has been described. Not only this but the tension sensor 51 is applicable also to the textile machine which handles yarns other than a false twisting machine.

1 False twisting machine 21 Second yarn guide (contact part)
51 Tension sensor (tension detector)
52 Leaf spring (movable member)
53 Magnet 54 Hall element (detection means)
55 Expansion member (correction means)
57 recess

Claims (4)

A movable member that contacts the traveling yarn and displaces according to the tension of the yarn;
A magnet attached to the movable member;
Detection means provided at a predetermined position and detecting the strength of the magnetic field of the magnet;
A tension detecting device comprising:
A correction means for correcting fluctuations in the magnetic field strength of the magnet due to temperature changes ;
The tension detecting device is characterized in that the correcting means displaces the magnet in a direction approaching the detecting means as the temperature rises . The correction means is a member that is provided between the movable member and the magnet and expands as the temperature rises, and displaces the magnet in a direction approaching the detection means due to expansion as the temperature rises. The tension detection device according to claim 1 . Said correction means, tension detecting apparatus according to claim 1 or 2, characterized in that a member having a heat insulating property. The movable member is provided in a contact portion with which the traveling yarn contacts, and a concave portion in which the yarn travels in an internal space provided at at least one position before and after the traveling direction of the yarn with respect to the contact portion. The tension detecting device according to any one of claims 1 to 3 , wherein: