JP2004033619A - Thread tension device - Google Patents

Abstract

Provided is a thread tension device that can easily adjust rotation resistance applied to a spinning wheel or the like by adding the spinning resistance to the spinning wheel or the like while reducing the rotation resistance.
A thrust bearing inner ring provided on a shaft that rotates integrally with a spinning wheel receives a pressing force from a thrust bearing outer ring via a thrust bearing shown in FIG. This pressing force is generated by the piezo element and the pressurizing spring. Since the rolling element 134 also rotates with the rotation of the spinning wheel and the shaft, the rotation resistance is reduced. In addition, the rolling axis of the rolling element 134 has an inclination of θ with respect to the radial direction of the retainer 132. For this reason, while the rolling element 134 attempts to move while rolling in the direction of arrow A, the actual moving direction of the rolling element 134 due to the rotation of the spinning wheel is in the direction of arrow B, and a resistance corresponding to the angle difference between the two is added. . For this reason, the rotation resistance can be appropriately reduced.
[Selection diagram] FIG.

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a thread tension device that adjusts the tension or usage of a yarn by a spinning wheel that rotates in accordance with the transport of the yarn, and more particularly, adjusts a rotational resistance applied to the spinning wheel or a rotating unit that rotates integrally with the spinning wheel. Related to technology.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a thread tension device including a spinning wheel that comes into contact with a thread and rotates in accordance with the transport of the thread has been known. As disclosed in Japanese Patent Application Laid-Open No. 63-63489, a thread tensioner provided with such a spinning wheel is provided with a contact member that comes into contact with the spinning wheel or a rotating portion that rotates integrally with the spinning wheel (hereinafter referred to as a spinning wheel or the like). Thus, the contact member is pressed against the spinning wheel or the like, and a rotational resistance is applied to the spinning wheel or the like by frictional force generated between the wheel and the like and the contact member.
[0003]
Further, the force generated by a force generating means such as a solenoid, a pulse motor, and a piezo element (piezoelectric element) is transmitted to the contact member in the contact direction as it is. In a device such as a sewing machine provided with a thread adjusting device, it is necessary to adjust the rotational resistance applied to the spinning wheel and the like as needed in order to adjust the tension and the amount of use of the thread to the operating state of the device. Therefore, for example, in a sewing machine, when the needle bar reaches a predetermined height, control is performed to supply a voltage to the piezo element and press the contact member against a spinning wheel or the like.
[0004]
[Problems to be solved by the invention]
However, when the force generated by the force generating means such as a piezo element is directly transmitted to the contact member, a large rotational resistance is applied to the spinning wheel or the like only by generating a small force on the piezo element or the like. For this reason, it was extremely difficult to finely adjust the rotation resistance. On the other hand, in a device such as a sewing machine, if the rotation resistance is too large and the spinning wheel does not rotate more than an appropriate amount of rotation, thread breakage occurs or the fabric is stretched. Conversely, if the rotation resistance is too small and the spinning wheel rotates more than an appropriate amount of rotation, the stitch thread tightness is weak or the thread is entangled.
[0005]
As described above, conventionally, there has been a problem that it is difficult to control the usage amount of the yarn to an appropriate range by adding an appropriate rotation resistance to the spinning wheel or the like. Therefore, an object of the present invention is to provide a thread tension device that can easily adjust the rotation resistance applied to a spinning wheel or the like by adding the rotation resistance to the spinning wheel or the like while reducing the rotation resistance.
[0006]
Means for Solving the Problems and Effects of the Invention
The invention according to claim 1, which has been made to achieve the above object, provides a spinning wheel that contacts a yarn and rotates in accordance with the conveyance of the yarn, and a rotational resistance against rotation of the spinning wheel or a rotating unit that rotates integrally with the yarn wheel. A force generating means for generating a force for power transmission, and a transmission path for transmitting the force from the force generating means to the spinning wheel or the rotating portion, and rolling in contact with the spinning wheel or the rotating portion. And a rolling element for reducing the rotation resistance due to the force, wherein the rolling axis of the rolling element is set to a predetermined value with respect to a cross section including the rotating shaft of the spinning wheel or the rotating unit. It is characterized by being inclined so as to form an angle.
[0007]
The present invention thus configured includes a force generating means for generating a force for rotational resistance to the spinning wheel or a rotating portion (= spin wheel or the like) which rotates integrally with the spinning wheel. In the transmission path of the above-mentioned force, there is provided a rolling element that reduces the rotation resistance due to the above-mentioned force by rolling in contact with the spinning wheel or the like. That is, the rolling of the rolling element causes rolling in the transmission path of the force, and the rotational resistance corresponding to the force generated by the force generating means is reduced as compared with the case where the rolling element does not exist.
[0008]
In addition, the rolling axis of the rolling element is inclined so as to form a predetermined angle with respect to the cross section including the rotation axis of the spinning wheel or the like. Therefore, while the rolling element attempts to move in a direction perpendicular to the rolling axis, the actual moving direction of the rolling element accompanying rotation of the spinning wheel or the like is a direction perpendicular to the cross section. The sliding resistance according to the angle difference is added.
[0009]
That is, when the rolling shaft is disposed parallel to the cross section, the slip may be excessively large. However, in the present invention, the slip is appropriately suppressed by providing the inclination. In addition, the rotational resistance applied to the spinning wheel and the like can be reduced appropriately. Therefore, in the present invention, the force to be generated by the force generating means can be appropriately increased in order to adjust the rotational resistance applied to the spinning wheel or the like to an appropriate range. This makes it easier to perform the operation.
[0010]
According to a second aspect of the present invention, in addition to the configuration of the first aspect, when the spinning wheel is rotated in a direction in which the thread is fed during sewing, the rolling shaft of the rolling element has a predetermined angle with respect to the cross section. When the spinning wheel rotates in the direction opposite to the unwinding direction, the rolling element is tilted so that the rolling axis of the rolling element is disposed parallel to the cross section. It is characterized by being provided freely.
[0011]
In the present invention, by providing the rolling element so as to be tiltable, when the spinning wheel is rotated in the yarn feeding direction at the time of sewing, the rolling axis of the rolling element is at the predetermined angle with respect to the cross section. Incline. For this reason, the rotational resistance applied to the spinning wheel and the like can be appropriately reduced, and the effect of the first aspect of the invention is produced. On the other hand, when the spinning wheel rotates in the direction opposite to the feeding direction, the rolling element is tilted so that the rolling axis is arranged in parallel with the cross section. For this reason, as mentioned in the description of the first aspect, the rolling element can be easily rolled in the force transmission path, and the rotational resistance can be greatly reduced. Therefore, according to the present invention, when the thread is dragged in the direction of the thread spool when sewing is interrupted, the rotational resistance can be extremely reduced. Therefore, according to the present invention, in addition to the effect of the first aspect, it is extremely easy to drag the thread in the direction of the thread spool when sewing is interrupted.
[0012]
According to a third aspect of the present invention, in addition to the configuration of the first or second aspect, the rolling element is supported by a bearing that rotates coaxially with the spinning wheel and the rotating portion.
In the present invention, since the rolling elements are supported by bearings that rotate coaxially with the spinning wheel or the like, the configuration for disposing the rolling elements on the above-described force transmission path becomes extremely simple. In addition, such a configuration can be extremely miniaturized. Therefore, according to the present invention, in addition to the effects of the first or second aspect of the present invention, there is an effect that the configuration can be simplified, the cost can be further reduced, and the device can be further reduced in size.
[0013]
The invention according to a fourth aspect is characterized in that, in addition to the configuration according to any one of the first to third aspects, the force generating means is a piezo element.
The piezo element has good responsiveness, and can extremely easily adjust a force generated by adjusting an applied voltage, and is excellent in force reproducibility and stability. In the present invention, since the piezo element is used as the force generating means, in addition to the effect of the invention according to any one of claims 1 to 3, it is possible to further easily adjust the rotational resistance applied to the spinning wheel and the like. As a result, there is an effect that the reproducibility and stability of the rotational resistance are excellent.
[0014]
According to a fifth aspect of the present invention, in addition to the configuration according to any one of the first to third aspects, the force generating means has a piezo element and a pressurizing spring for generating the force. When a voltage is supplied, the piezo element and the pressurized spring generate the force, and when no voltage is supplied to the piezo element, the pressurized spring generates the force. .
[0015]
In the present invention, a piezo element and a pressurizing spring are provided as force generating means, and when a voltage is supplied to the piezo element, the piezo element and the pressurizing spring generate the force. For this reason, by adjusting the voltage applied to the piezo element, the rotational resistance applied to the spinning wheel and the like can be adjusted very easily. On the other hand, in the present invention, when no voltage is supplied to the piezo element, the pressurizing spring generates the above force. For this reason, even when the voltage supply to the piezo element is cut off, the above-described force can be continuously generated by the pressurized spring, and the rotation resistance can be continuously applied.
[0016]
Therefore, according to the present invention, in addition to the effect of the invention according to any one of claims 1 to 3, the adjustment of the rotational resistance applied to the spinning wheel and the like can be further facilitated, and the voltage supply to the piezo element is cut off. In such a case, an effect is obtained that inadvertent rotation of the spinning wheel and the like can be prevented.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram illustrating an appearance of a sewing machine 10 to which the present invention is applied. As shown in FIG. 1, a sewing machine 10 of the present embodiment forms a stitch on a work cloth W by a needle 12 into which a needle thread T is inserted, and a needle bar 14 for moving the needle 12 up and down, and And a thread spool 16 for holding the upper thread T in a wound shape. A balance 18, a thread tension device 20, and an auxiliary thread tension device 22 are provided on the transport path of the upper thread T from the thread spool 16 to the needle 12 in this order from the needle 12.
[0018]
In this sewing machine 10, the thread tension device 20 is detachably attached to an attachment hole (not shown) formed in the front sewing machine frame 10a. The thread tension device 20 extends in the front-rear direction (the direction perpendicular to the plane of FIG. 1), and is mounted so as to protrude forward from the sewing machine 10. In addition, if the thread tension device has a configuration in which the radius and the shape of the root portion of the thread tension device can be applied to the mounting hole, even if the function and the configuration are different, the thread tension device can be replaced and mounted. The sewing machine 10 is configured.
[0019]
FIG. 2 is a block diagram illustrating a configuration of a control system of the sewing machine 10. As shown in FIG. 2, a CPU 24 that executes various processes as a control device of the entire sewing machine 10 is connected to a ROM 26 that stores various programs and a RAM 28 that is used during the execution of the programs. And outputs a drive signal to the sewing machine motor 36 and a piezo element 106 described later. Further, a detection signal of a needle position detector 38 for detecting the rotation position of an upper shaft (not shown) driven by the sewing machine motor 36 (that is, the vertical movement position of the needle 12) is input to the CPU 24.
[0020]
FIG. 3 is a longitudinal sectional view illustrating a configuration of the thread tension device 20. As shown in FIG. 3, the thread tension device 20 includes a substantially hollow cylindrical body 100 extending in the front-rear direction, a spinning wheel 102 that rotates in accordance with the transport of the upper thread T during sewing by the needle 12, the balance 18, and the like. To a hard metal or resin shaft 104, which rotates together with the spinning wheel 102, and serves as a rotation axis of the spinning wheel 102, a piezo element 106, and a piezo element 106 that generate a force for rotational resistance to rotation of the spinning wheel 102 and the shaft 104 And a pressurizing spring 110 for generating a pressurization regardless of application of a voltage to the piezo element 106.
[0021]
The body 100 is made of hard metal or resin, and a front cover 112 and a rear cover 114 are detachably attached to its front and rear ends by screws 116 and 118, respectively. A spinning wheel 102 disposed in front of the body 100 is fixed to a front end 104a (see FIG. 4) of a shaft 104 disposed in an internal space of the body 100 and extending in the front-rear direction.
[0022]
As shown in the perspective view of FIG. 4, the shaft 104 has a front end 104a to which the spinning wheel 102 is attached, a radial bearing 104b having a larger radius than the front end 104a, and a front thrust bearing guide having a larger radius. A thrust bearing inner ring 104d having a larger radius, and a rear thrust bearing guide 104e having the same radius as the front thrust bearing guide 104c, all of which are concentric. is there.
[0023]
Returning to FIG. 3, the shaft 104 is housed on the front side of the internal space of the body 100 with its front end portion 104a protruding forward. The radial bearing portion 104b of the shaft 104 is rotatably supported by two radial bearings 120 and 122 which are separated in the front-rear direction, and the spinning wheel 102 and the shaft 104 rotate integrally. The two radial bearings 120 and 122 are arranged apart from each other in the front-rear direction with a spacer 124 therebetween, and are fixed to the inner surface of the body 100. Each of the radial bearings 120 and 122 has a plurality of spherical rolling elements, and its rotational friction is extremely small, and hardly adds resistance to the rotation of the spinning wheel 102 and the shaft 104. The radial bearings 120 and 122 are immovably mounted on the inner side surface of the body 100 in the front-rear direction.
[0024]
A front thrust bearing outer ring 126 is fixed to the inner surface of the body 100 further rearward of the rear radial bearing 122 so as to be non-rotatable and non-movable in the front-rear direction. The thrust bearing outer ring 126 is made of hard metal or resin, and has a circular through portion formed at the center thereof for supporting the thrust bearing guide 104c with a slight gap. That is, the thrust bearing outer ring 126 is arranged so as not to cause friction with the shaft 104.
[0025]
In the internal space of the body 100 further behind the front thrust bearing outer ring 126, a front thrust bearing 130 is disposed between the rear surface of the thrust bearing outer ring 126 and the front surface of the thrust bearing inner ring 104d. The thrust bearing 130 includes a substantially disk-shaped retainer 132 and twelve cylindrical rolling elements 134, as shown in a sectional view taken along the line AA of FIG. 5 (the body 100 is omitted).
[0026]
A circular penetrating part 132a is formed at the center of the retainer 132, and twelve rectangular penetrating parts 132b are formed around it at equal angles. Further, each penetrating portion 132b has a predetermined angle θ in a certain direction with respect to the radial direction of the retainer 132 (with respect to the cross section including the rotation axis of the retainer 132). The rolling elements 134 are fitted into the penetrating portions 132b, respectively. The rolling element 134 is formed of a hard metal or resin into a column shape having a radius that slightly protrudes forward and backward from the retainer 132. Therefore, as shown in FIG. 3, all the rolling elements 134 of the thrust bearing 130 contact the rear surface of the front thrust bearing outer ring 126 and the front surface of the thrust bearing inner ring 104d.
[0027]
The thrust bearing guide 104c on the front side is inserted into the through portion 132a, and the retainer 132 is slidably and rotatably guided with respect to the shaft 104. Note that friction is generated between the inner wall surface of the penetrating portion 132a and the outer peripheral surface of the thrust bearing guide portion 104c, though the friction is small, and the shaft is held in the same direction as the shaft 104 at a rotation speed lower than the rotation speed of the shaft 104 The vessel 132 rotates.
[0028]
A thrust bearing 136 configured similarly to the thrust bearing 130 is disposed in the internal space of the body 100 further behind the thrust bearing inner ring 104d. A thrust bearing guide portion 104e on the rear side is inserted into a circular through portion of the retainer 138 of the thrust bearing 136, and is guided to be rotatable while sliding with respect to the shaft 104. The thrust bearing 136 is arranged such that the rolling element 140 held by the retainer 138 contacts the rear surface of the thrust bearing inner ring 104d. The friction between the inner wall surface of the penetrating portion of the retainer 138 and the outer peripheral surface of the thrust bearing guide portion 104 e is small but small, and the rotational speed is lower than the rotational speed of the shaft 104. The retainer 138 rotates in the direction. Further, the outer peripheral surface of the thrust bearing inner ring 104d and the outer peripheral surfaces of the two retainers 132 and 138 are arranged with a gap from the inner wall surface of the body 100, and the outer peripheral surface of the thrust bearing inner ring 104d and the retainers 132 and 138. No friction occurs between the outer peripheral surface of the body 100 and the inner wall surface of the body 100.
[0029]
A rear thrust bearing outer ring 142 is disposed in the internal space of the body 100 further behind the rear thrust bearing 136. The thrust bearing outer ring 142 is formed of a hard metal or resin into a disk shape having substantially the same diameter as the thrust bearing inner ring 104d. Therefore, all the twelve cylindrical rolling elements 140 of the rear thrust bearing 136 contact both the rear surface of the thrust bearing inner ring 104d and the front surface of the thrust bearing outer ring 142. The front surface of the rear thrust bearing outer ring 142 is disposed with a gap between the rear end of the shaft 104 and the rear end thereof so as not to cause friction therebetween. Further, the outer peripheral surface of the rear thrust bearing outer ring 142 is arranged with a gap from the inner wall surface of the body 100 so that friction is not generated between the outer peripheral surface of the thrust bearing outer ring 142 and the inner wall surface of the body 100. Have been.
[0030]
In the internal space of the body 100 further behind the rear thrust bearing outer ring 142, a pressurizing spring 110, which is a compression spring, is arranged in a compressed state, and the front end thereof is provided on the rear surface of the thrust bearing outer ring 142 at the rear end. The portions are in contact with the front surface of the spring adjustment ring 144, respectively. The spring adjusting ring 144 is fitted on the inner wall surface of the body 100 and is fixed by a spring adjusting screw 146 so as not to rotate and move in the front-rear direction.
[0031]
Therefore, the pressurizing spring 110 always urges the rear thrust bearing outer ring 142 forward by its elastic force, and no voltage is supplied to the piezo element 106 by the forward urging force of the pressurizing spring 110. If not, the components are in contact as shown in FIG. That is, the thrust bearing outer ring 142, the twelve rolling elements 140 of the thrust bearing 136, the thrust bearing inner ring 104 d, the twelve rolling elements 134 of the thrust bearing 130, and the front thrust bearing outer ring 126 are in contact with each other, and between them. It is configured such that rolling resistance and sliding resistance due to friction (that is, rotation resistance due to the pressurized spring 110) are generated.
[0032]
Further, as shown in FIG. 3, a hard steel ball 150, a hard metal or resin head adapter 152, and a piezo element 106 are placed in the central space of the pressurizing spring 110 in this order from the front. And are located away from it. The head adapter 152 is fixed to the front end of the piezo element 106, and the piezo adjustment shaft 106 a at the rear end of the piezo element 106 is fixed so as not to rotate and move by a piezo adjustment screw 156 screwed to the rear cover 114. When a voltage is supplied, the piezo portion 106b before the piezo adjustment shaft 106a is displaced (extended) in the front-rear direction according to the magnitude of the voltage. Note that the piezo adjustment screw 156 abuts on a tapered portion 106c formed at the rear end of the piezo adjustment shaft 106a, whereby the fixed position of the piezo adjustment shaft 106a is adjusted back and forth.
[0033]
The steel ball 150 described above is fitted in a pair of mortar-shaped recesses formed in the center of the rear surface of the rear thrust bearing outer ring 142 and the center of the front surface of the head adapter 152. The thread tension device 20 is configured so as to eliminate variations in the shape and dimensions of the thread tension device.
[0034]
Next, the operation of the thread tension device 20 thus configured will be described. When a voltage is supplied to the piezo element 106, the force generated based on the voltage is applied to the head adapter 152, the steel ball 150, the rear thrust bearing outer ring 142, the rear thrust bearing 136, the thrust bearing inner ring 104d, and the front side. Through the thrust bearing 130 on the stationary thrust bearing outer ring 126.
[0035]
As a result, the thrust bearing inner ring 104d as a part of the shaft 104 is sandwiched, and the above-described rolling resistance and sliding resistance due to friction act as rotation resistance for suppressing rotation of the spinning wheel 102 and the shaft 104. Note that such a force acts to some extent by the urging force of the pressurizing spring 110 even when no voltage is supplied to the piezo element 106 as described above. When a voltage is supplied to the piezo element 106, the resultant force of the force generated by the piezo element 106 and the urging force of the pressurizing spring 110 acts as the rotation resistance.
[0036]
A thrust bearing outer ring 126 fixed to the body 100 and a thrust bearing outer ring 142 whose rotation is prevented by a detent (not shown) and a thrust bearing inner ring 104d as a part of the shaft 104 have a thrust. Bearings 130 and 136 are provided. For this reason, the rolling elements 134 and 140 also rotate with the rotation of the spinning wheel 102 and the shaft 104, so that the rotational resistance to the rotation of the spinning wheel 102 and the shaft 104 is reduced. In other words, the rotation of the rolling elements 134 and 140 causes rolling in the transmission path of the force from the pressurizing spring 110 and the piezo element 106 to the thrust bearing inner ring 104d, and directly sandwiches the thrust bearing inner ring 104d between the thrust bearing outer rings 126 and 142. Rotational resistance is reduced as compared with the case of attaching.
[0037]
Moreover, the rolling axes of the rolling elements 134 and 140 have an inclination of θ with respect to the radial direction of the retainers 132 and 138 as shown in FIG. Only shown). For this reason, while the rolling elements 134 and 140 roll and move in the direction of arrow A, the actual moving direction of the rolling elements 134 and 140 accompanying the rotation of the spinning wheel 102 and the shaft 104 is in the direction of arrow B. The resistance according to the angle difference is added. That is, when the arrows A and B are parallel to each other, the slip may be excessively large. However, in the present embodiment, since the angle difference θ exists between the arrows A and B, the slip is appropriately suppressed. Therefore, the rotational resistance applied to the spinning wheel 102 and the shaft 104 can be reduced appropriately.
[0038]
Therefore, even when the applied voltage to the piezo element 106 is controlled as follows to adjust the rotational resistance of the spinning wheel 102, the force to be generated by the piezo element 106 can be appropriately increased. Can be easily adjusted. Since the body 100, the thrust bearing inner ring 104d, the rolling elements 134 and 140, the thrust bearing outer rings 126 and 142, and the steel ball 150 are formed of a hard material, the piezo element 106 is generated. If a force acts between these components, it does not dent like felt.
[0039]
In such a thread tension device 20, when the voltage supplied to the piezo element 106 is increased from the low standby voltage (0V) to the high suppression voltage (100V), and the force generated by the piezo element 106 increases, the cylindrical roller The rolling resistance and the sliding resistance of the moving bodies 134 and 140 also increase, the rotation resistance for suppressing the rotation of the spinning wheel 102 and the shaft 104 also increases, and the spinning wheel 102 is less likely to rotate. Conversely, when the voltage supplied to the piezo element 106 is reduced from the high suppression voltage to the low standby voltage, and the force generated by the piezo element 106 is reduced, the rolling resistance and the sliding resistance of the rolling elements 134 and 140 are also reduced, and the wheel The rotation resistance that suppresses the rotation of the shaft 102 and the shaft 104 is also reduced, so that the spinning wheel 102 smoothly rotates.
[0040]
The voltage supplied to the piezo element 106 is switched and controlled by the CPU 24 according to the sewing based on the detection signal of the needle position detector 38. The characteristic of the piezo element 106 is, for example, the relationship between the voltage supplied to the piezo element 106 and the generated rotational resistance as shown in FIG. Further, the standby voltage is not limited to 0 V, and may be a moderately low voltage. The suppression voltage is not limited to 100 V, and the voltage may be switched to a voltage value appropriately higher than the standby voltage.
[0041]
The CPU 24 controls the voltage to be supplied to the piezo element 106 to be higher to generate a large force as compared with the case where the rolling and slipping are not generated without providing the thrust bearings 130 and 136 as in the related art. I can do it. Moreover, since the voltage supplied to the piezo element 106 may be lower than when θ = 0, the control of the CPU 24 becomes extremely easy.
[0042]
In the above embodiment, the shaft 104 corresponds to a rotating unit, the piezo element 106 and the pressurizing spring 110 correspond to force generating means, and the retainers 132 and 138 correspond to bearings. Further, the present invention is not limited to the above-described embodiment at all, and can be implemented in various forms without departing from the gist of the present invention.
[0043]
For example, one of the thrust bearings 130 and 136 may be omitted as long as the rotational resistance is appropriately reduced. However, when the thrust bearing inner ring 104d is sandwiched between the two thrust bearings 130 and 136 from the front and rear as in the present embodiment, the rotational resistance can be more favorably reduced and the above control can be further facilitated. Similarly, in the above-described embodiment, the rolling elements 134 and 140 are always in contact with the thrust bearing inner ring 104d and the thrust bearing outer rings 126 and 142, but some of the rolling elements 134 and 140 are in contact with alternative ones. Both the configuration and the configuration in which the rolling elements 134 and 140 protrude forward or rearward from the cages 132 and 138 are applicable as long as the rotational resistance is appropriately reduced.
[0044]
Further, the shape of the rolling elements 134 and 140 is not limited to a columnar shape, but may be a barrel-shaped shape with a bulging center, a concavity with a depressed center, a truncated cone shape, a shape with both ends formed into a spherical shape, and the like. Various shapes can be applied. Further, the rolling elements 134 and 140 may be arranged at irregular intervals around the retainers 132 and 138 if the rotational resistance is appropriately reduced.
[0045]
The rolling elements 134 and 140 may all have the same shape, material, and the like. However, if the rotational resistance is appropriately reduced, the rolling elements 134 and 140 may have different shapes. Only some of the rolling elements 134, 140 may be different in size, shape, material, or hardness from the other rolling elements 134, 140.
[0046]
Further, the retainers 132 and 138 may be formed in a conical surface shape instead of a flat plate shape, and the above-described inclination θ may be different for each penetrating portion 132b. For example, ± may be reversed every other θ. Further, the shape of the penetrating portion 132b does not necessarily need to be similar to the outer shape of the rolling elements 134 and 140, and may be various shapes.
[0047]
FIG. 7 shows an example in which the penetrating portion 132b is formed in a fan shape having an arc on the outer peripheral side. One diameter of the penetrating portion 132b extends along the radial direction, and the other diameter has an angle of θ with respect to the radial direction as described above. For this reason, the rolling element 134 is provided so as to be tiltable from the attitude along the radial direction to the above-described tilted θ attitude. In addition, in the example of FIG. 7, both ends of the rolling element 134 are formed in a spherical shape in order to facilitate the above-described tilting, but may have another shape.
[0048]
In the thrust bearing 130 configured as described above, when the thrust bearing inner ring 104d rotates in the direction of the large arrow in FIG. 7A as the upper thread T is conveyed in the direction of the needle 12, the rolling element 134 becomes small. As shown in the figure, it is arranged in the posture inclined by θ. In this state, the same operations and effects as those of the above-described embodiment occur. On the other hand, when the thrust bearing inner ring 104d rotates in the direction of the large arrow in FIG. 7B, the rolling elements 134 are disposed in a position along the radial direction as indicated by the small arrow. In this state, the rotational resistance applied to the spinning wheel 102 and the shaft 104 can be greatly reduced. Therefore, when the upper thread T is dragged in the direction of the thread spool 16 when sewing is interrupted, it is extremely easy to pull the upper thread T by hand.
[0049]
When the rolling element 134 is provided so as to be tiltable in this manner, the rolling element 134 may be biased to any tilting position by a torsion coil spring or the like. In this case, the initial value of the rotation resistance applied to the spinning wheel 102 and the shaft 104 can be made constant regardless of the past rotation direction of the spinning wheel 102. Although only the thrust bearing 130 is shown in FIG. 7, the thrust bearing 136 may be similarly configured, or only one of the thrust bearings 130 and 136 may be configured as described above.
[0050]
Furthermore, the present invention provides a thread-like device for other purposes such as a thread stand, a spinning device, a knitting machine, a motor winding machine, a fishing reel, a wire electric discharge machine, various types of thread winding machines, etc. It can be applied to various devices that handle objects. In the above embodiment, the piezo element 106 and the pressurizing spring 110 are used as the force generating means. However, only the piezo element 106 may be used, and another actuator such as a pulse motor, an air cylinder, or a solenoid may be used. You may.
[0051]
However, the piezo element 106 can extremely easily adjust the force generated by adjusting the applied voltage, and is excellent in force reproducibility and stability. For this reason, in the above embodiment, the adjustment of the rotational resistance applied to the spinning wheel 102 and the shaft 104 can be further facilitated, and the reproducibility and stability of the rotational resistance are excellent. Moreover, in the above-described embodiment, even when the voltage supply to the piezo element 106 is cut off, the above-described force can be continuously generated by the pressurizing spring 110, and the rotation resistance can be continuously applied. Therefore, in the above-described embodiment, the adjustment of the rotational resistance applied to the spinning wheel 102 and the shaft 104 can be further facilitated, and even when the supply of voltage to the piezo element 106 is cut off, the rotation of the Can be prevented.
[0052]
In the above-described embodiment, the retainers 132 and 138 are disc-shaped. On the other hand, each of them may be formed to be inclined at a predetermined angle θ in a certain direction. The front and rear positions of the piezo adjustment shaft 106a may be adjusted by turning the piezo adjustment shaft 106a forward and backward by screwing and screwing the piezo adjustment shaft 106a and the rear cover 114, respectively. .
[Brief description of the drawings]
FIG. 1 is a schematic diagram illustrating an appearance of a sewing machine to which the present invention is applied.
FIG. 2 is a block diagram illustrating a configuration of a control system of the sewing machine.
FIG. 3 is a longitudinal sectional view illustrating a configuration of a thread tension device of the sewing machine.
FIG. 4 is a perspective view showing a configuration of a shaft of the thread tension device.
5 is a cross-sectional view taken along line AA of FIG. 2, and is a diagram illustrating a configuration of a thrust bearing.
FIG. 6 is a graph showing characteristics of a piezo element of the thread tension device.
FIG. 7 is a front view illustrating a modified example of the thrust bearing.
[Explanation of symbols]
10 sewing machine 12 needle 16 thread spool 20 thread tension device
22: auxiliary thread tension device 38: needle position detector 102: spinning wheel
104: Shaft 104d: Thrust bearing inner ring 106: Piezo element
108 Lead wire 110 Pressurizing spring 126, 142 Thrust bearing outer ring 130, 136 Thrust bearing 132, 138 Cage
132a, 132b ... penetrating parts 134, 140 ... rolling elements

Claims (5)

A spinning wheel, which comes into contact with the yarn and rotates according to the conveyance of the yarn,
A force generating means for generating a force for rotational resistance to rotation of the spinning wheel or a rotating portion that rotates integrally with the spinning wheel,
A rolling device is provided on the transmission path of the force from the force generating means to the spinning wheel or the rotating portion, and rolls by contacting the spinning wheel or the rotating portion to reduce the rotational resistance due to the force. Moving body,
A thread tension device comprising:
A thread tension device characterized in that a rolling axis of the rolling element is inclined so as to form a predetermined angle with respect to a cross section including a rotation axis of the spinning wheel or the rotating portion. When the spinning wheel rotates in the direction in which the thread is fed during sewing, the rolling axis of the rolling element is inclined so as to form the predetermined angle with respect to the cross section, and the spinning wheel is in a direction opposite to the feeding direction. 2. The thread tension device according to claim 1, wherein the rolling element is provided to be tiltable so that the rolling axis of the rolling element is disposed parallel to the cross section when the roller rotates. . 3. The thread tension device according to claim 1, wherein the rolling element is supported by a bearing that rotates coaxially with the spinning wheel and the rotating portion. The thread tension device according to any one of claims 1 to 3, wherein the force generating means is a piezo element. The force generating means has a piezo element and a pressurized spring for generating the force, and when a voltage is supplied to the piezo element, the piezo element and the pressurized spring generate the force, The thread tension device according to any one of claims 1 to 3, wherein the pressure spring generates the force when no voltage is supplied to the piezo element.

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