JP3760512B2 - Yarn tension detection sensor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a yarn tension detection sensor, and more particularly to a yarn tension detection sensor for detecting a yarn tension at the time of winding a yarn in a spinning machine.
[0002]
[Prior art]
Conventionally, as this type of yarn tension detection sensor, one using a potentiometer or one described in Japanese Patent Publication No. 6-29814 is known. The yarn tension detection sensor described in the publication includes a movable yarn guide that is provided between two fixed yarn guides and that is acted on at right angles to the traveling direction of the yarn by the traveling of the yarn. It has a structure to hang a thread on. Specifically, the movable yarn guide is attached to the open end portion of the spring plate, one end of which is fixed to the housing. A magnet is attached under the movable yarn guide, and the magnet is set to face the Hall effect sensor in a state where the yarn is hung. And the change of the magnetic flux density from the magnet which moves up and down according to the yarn tension at the time of winding the yarn is detected by the Hall effect sensor, and the yarn tension is measured.
[0003]
[Problems to be solved by the invention]
However, in the case of using the potentiometer, since the bearing is constituted by several types of bearings, the size is increased and the cost is high. Moreover, since the brush was used for the contact of the rotating body, the durability was lacking.
On the other hand, in the yarn tension detection sensor described in the above publication, since the movable yarn guide and the magnet are attached to the open end of the spring plate, when the yarn traveling speed increases, the spring plate abnormally vibrates, There was a problem that the movement could not follow the tension of the thread, and the jumping of the magnet, the entanglement of the thread and the thread breakage occurred, and the thread tension could not be measured accurately.
[0004]
SUMMARY OF THE INVENTION An object of the present invention is to provide a yarn tension detection sensor that is small and durable, and that can accurately measure the yarn tension even when the yarn traveling speed is high.
[0005]
[Means and Actions for Solving the Problems]
In order to achieve the above object, a yarn tension detection sensor according to the present invention has a wear-resistant shaft member fixed at a fixed position and a rigid rigidity that engages with a substantially half circumferential portion of the outer peripheral surface of the shaft member. A lever member made of a body, an elastic member that engages with both ends of the lever member to elastically hold the lever member, a thread guide member that is rotatably mounted on the lever member, and a rotating member that rotates on the lever member A magnet provided with a slight eccentricity from the center and a magnetoresistive element provided at a fixed position facing the magnet are provided.
[0006]
That is, according to the present invention, the rigid body lever member is elastically pressed against the wear-resistant shaft member and held rotatably, and a thread guide member and a magnet for guiding the traveling of the thread are attached to the lever member. When the yarn tension does not act on the yarn guide member, the lever member is kept balanced by the elastic member and is stationary at a predetermined angle. The rotation angle in the stationary state is 0 °. When the yarn travels at a high speed, the lever member receives a rotational force in one direction via the yarn guide member due to the tension of the yarn, and slightly rotates about the shaft member as a fulcrum. The magnet rotates together with the lever member, and the magnetic flux density of the magnet acting on the magnetoresistive element fixed at a fixed position changes.
[0007]
The running tension of the yarn acts as a change in the magnetic flux density to the magnetoresistive element based on the rotation angle of the lever member / magnet, and the change in the magnetic flux density is detected as a change in resistance (voltage) by the magnetoresistive element. Thus, the tension of the yarn is measured as a voltage change of the magnetoresistive element.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of a yarn tension detection sensor according to the present invention will be described with reference to the accompanying drawings.
In FIG. 1 and FIG. 2, the yarn tension detection sensor generally includes a first fixed plate 1, a second fixed plate 10, a movable lever 15, a movable yarn guide roller 19, coil springs 21 to 24, a magnet 25, and a magnetoresistive element 30. It is composed of.
[0009]
A support block 2 is fixed to the first fixing plate 1, and a shaft portion 3 made of an abrasion resistant material (for example, ceramic) is provided on the support block 2. Further, fixed yarn guide rollers 7 and 8 are rotatably mounted on the first fixed plate 1 via blocks 5 and 6.
The movable lever 15 is made of a rigid body, and a semicircular recess 16 formed on one side surface is engaged with the shaft portion 3. The movable lever 15 is elastically held by providing four coil springs 21 to 24 in a compressed state with the coil springs 21 to 24 facing each other at both ends.
[0010]
The movable yarn guide roller 19 is rotatably attached to one end of the movable lever 15. The yarn 40 is stretched from the fixed yarn guide roller 7 to the movable yarn guide roller 19 and the fixed yarn guide roller 8, and travels in the direction of arrow a. These rollers 7, 8, and 19 are made of a wear-resistant material.
When no tension is applied to the yarn 40, the movable lever 15 maintains a balance by the spring force of each of the coil springs 21 to 24 and is stationary at the angle shown in FIG. At this time, the rotation angle θ of the movable lever 15 is set to 0 °.
[0011]
The magnet 25 has a rectangular shape and is attached to one side of the movable lever 15 via a block 26. The attachment position of the magnet 25 is a position slightly decentered from the shaft portion 3.
The magnetoresistive element 30 is attached to the second fixed plate 10 so as to face the magnet 25. Specifically, as shown in FIGS. 3 and 4, a pair of magnetoresistive elements MR1 and MR2 are arranged symmetrically about the shaft portion 3, and the movable lever 15 rotates in a balanced manner as described above. When the angle θ is 0 °, the magnet 25 is orthogonal to the magnetoresistors MR1 and MR2 and is opposed with a uniform area (see FIG. 3). The magnetoresistors MR1 and MR2 are electrically connected in series with each other, one end of MR1 is connected to the power supply terminal 31, and one end of MR2 is connected to the ground terminal 32. Further, an output terminal 33 is connected to the relay lines of MR1 and MR2.
[0012]
Next, the operation of the yarn tension detection sensor having the above configuration will be described.
When the yarn 40 is hung on the yarn guide rollers 7, 19, and 8 and the yarn 40 travels in the direction of arrow a, for example, at a high speed of 1200 m / min, the movable yarn guide roller 19 applies the force in the direction of arrow b due to the tension of the yarn 40. The movable lever 15 is rotated in the direction of arrow c with the shaft portion 3 as a fulcrum. Since the movable lever 19 is elastically held by the four coil springs 21 to 24, the movable lever 19 rotates to an angle θ that balances the tension of the yarn 40 and the elastic force of the coil springs 21 to 24. The magnet 25 also rotates with the rotation of the movable lever 15 (see FIG. 4), and the magnetic flux density acting on the magnetoresistive element 30 from the magnet 25 changes. This change in magnetic flux density is detected as a voltage change from the output terminal 33.
[0013]
In this way, by converting the tension of the thread 40 into the rotational force of the movable lever 15, even when the thread 40 travels at a high speed, the movable lever 15 can smoothly follow the tension of the thread 40. The magnet 25 also operates smoothly. Therefore, there is no possibility that the magnet 25 jumps, yarn entanglement or thread breakage occurs, and the yarn tension can be accurately measured. In particular, in this embodiment, since the movable lever 15 is rotatably held by the balance of the elastic force of the coil springs 21 to 24 on the wear-resistant shaft portion 3, the cost of a bearing or the like is required to hold the movable lever 15. There is no need to use large parts, and it can be manufactured inexpensively with a compact configuration.
[0014]
Here, the detection of the yarn tension by the magnetoresistive element 30 will be specifically described.
When the resistance values of the magnetoresistors MR1 and MR2 are R ₁ and R ₂ , and the power supply voltage input to the power supply terminal 31 is V _IN , the output voltage V _OUT of the output terminal 33 is expressed by the following equation (1). Is done.
V _OUT = {R ₂ / (R ₁ + R ₂ )} × V _IN (1)
[0015]
In the present embodiment, when the yarn 40 is not tensioned (yarn tension is 0 g), as shown in FIG. 3, the rotation angle θ of the movable lever 15 is 0 °, and the magnetoresistors MR1 and MR2 are They are set to face the magnet 25 with the same area. Accordingly, the resistance values of the magnetoresistive elements MR1 and MR2 in a state where no tension is applied to the yarn 40 are R ₁ = R ₂ = R ₀ , and the output voltage V _OUT0 of the magnetoresistive element 30 is expressed by the above equation (1). The following equation (2) is obtained.
V _OUT0 = V _IN / 2 (2)
[0016]
Next, when the yarn 40 travels at a high speed and 50 g of tension is applied to the yarn 40, the movable yarn guide roller 19 receives a force in the direction of the arrow b and moves to a position that balances with the elastic force of the coil springs 21 to 24. The lever 15 rotates smoothly. In the present embodiment, the balance position at a tension of 50 g is set to a position where the rotation angle θ of the movable lever 15 is 5 °. As shown in FIG. 4, the magnet 25 rotates with the rotation of the movable lever 15, the facing area between the magnetoresistive MR1 and the magnet 25 decreases, and the facing area between the magnetoresistive MR2 and the magnet 25 increases. Therefore, the magnetic flux density from the magnet 25 to the magnetoresistive element MR1 decreases, and the magnetic flux density to the magnetoresistive element MR2 increases. That is, the resistance value R ₁ of the magnetoresistor MR1 is R ₀ −ΔR, and the resistance value R ₂ of the magnetoresistor MR2 is R ₀ + ΔR. As a result, from the equation (1), the output voltage V _OUT5 of the magnetoresistive element 30 is _expressed by the following equation (3). In the present embodiment, the output voltage V _OUT is set to be 14 mV higher than the rotation angle of the movable lever 15 of 1 °.
V _OUT5 = (V _IN / 2) + (V _IN · ΔR / 2R ₀ ) (3)
[0017]
Further, when the tension applied to the thread 40 reaches 100 g, the movable lever 15 further rotates in the direction of the arrow c to a position that balances with the elastic force of the coil springs 21 to 24. In the present embodiment, the balance position at a tension of 100 g is the position at which the rotation angle of the movable lever 15 is 10 °. In this case, the facing area between the magnetoresistive MR1 and the magnet 25 is further reduced, and the facing area between the magnetoresistive MR2 and the magnet 25 is further increased. The resistance value R ₁ of the magnetoresistor MR1 is R ₀ −2ΔR, and the resistance value R ₂ of the magnetoresistor MR2 is R ₀ + 2ΔR. As a result, from the equation (1), the output voltage V _OUT10 of the magnetoresistive element 30 is _expressed by the following equation (4).
V _OUT10 = (V _IN / 2) + (V _IN · ΔR / R ₀ ) (4)
[0018]
FIG. 5 is a graph showing the relationship between the rotation angle of the movable lever 15 and the output voltage of the magnetoresistive element 30. Thus, the tension of the yarn 40 can be measured as a change in the output voltage V _OUT of the magnetoresistive element 30.
[0019]
The yarn tension detection sensor according to the present invention is not limited to the above embodiment, and can be variously modified within the scope of the gist thereof.
Particularly, magnets and magnetoresistors are used in various shapes according to specifications. The shape of the movable lever is the same, and the movable lever may be held in a tension state with respect to the coil spring.
[0020]
【The invention's effect】
As apparent from the above description, according to the present invention, since the lever member made of a rigid body is rotatably engaged / held with the wear-resistant shaft member by the balance of the elastic member, the yarn guide attached to the lever member The lever member and the magnet rotate smoothly by the thread tension acting from the member, and the tension can be accurately detected as a change in the output voltage of the magnetoresistive element without causing the magnet jumping, thread entanglement or thread breakage. In addition, it is not necessary to support the lever member with a bearing, so that the lever member can be configured compactly, and cost reduction can be achieved. Further, since a wear-resistant material is used for the shaft member without using a brush, the durability is excellent.
[Brief description of the drawings]
FIG. 1 is a plan view showing a yarn tension detection sensor according to an embodiment of the present invention.
FIG. 2 is a side view showing the yarn tension detection sensor.
FIG. 3 is an explanatory diagram showing a positional relationship between a magnetoresistive element and a magnet in the yarn tension detection sensor, and shows a case where the rotation angle of the movable lever is 0 °.
FIG. 4 is an explanatory diagram showing a positional relationship between a magnetoresistive element and a magnet in the yarn tension detection sensor, and shows a case where a movable lever rotates by a certain amount.
FIG. 5 is a graph showing the relationship between the rotation angle of the movable lever and the output voltage of the magnetoresistive element.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 3 ... Wear-resistant shaft part 15 ... Movable lever 19 ... Movable thread guide rollers 21-24 ... Coil spring 25 ... Magnet 30 ... Magnetoresistive element

Claims (1)

A wear-resistant shaft member fixed in place;
A lever member made of a rigid body that engages with a substantially half-circumferential portion of the outer peripheral surface of the shaft member and is rotatable;
An elastic member that engages both ends of the lever member and elastically holds the lever member;
A thread guide member rotatably mounted on the lever member;
A magnet provided at the lever member with a slight eccentricity from the center of rotation;
A magnetoresistive element provided at a fixed position facing the magnet;
A yarn tension detection sensor comprising:

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