JP6477987B1 - sewing machine - Google Patents

Abstract

The sewing machine (100) captures the upper thread inserted through the needle hole of the sewing needle (131) to entangle the upper thread and the lower thread (132), and a balance having a small hole through which the upper thread is inserted. (133), conveying means (P1) for conveying the sewing object, intermediate presser (135) for preventing the sewing article from lifting, driving source (136) for driving the intermediate presser (135), and conveying means When the upper thread comes into contact with the intermediate presser (135) when (P1) conveys the workpiece, a tension monitoring unit monitors the upper thread tension based on the load applied to the intermediate presser (135) from the upper thread. And comprising.

Description

The present invention relates to a sewing machine including an intermediate presser that presses a sewing object during sewing.

Conventionally, the upper thread of the sewing machine is supplied along a thread path starting from a supply source such as a thread winding installed in an arm part or a stand and starting from a sewing needle that is a consumption part of the upper thread.

Patent Document 1 discloses an upper thread tension detector that detects the tension of an upper thread during a sewing operation by providing a piezoelectric element in the thread path described above. Patent Document 1 describes a sewing machine in which a piezoelectric element is arranged at a position where it can come into contact with an upper thread, and the thread breakage is detected when the upper thread comes into contact with the piezoelectric element. In Patent Document 2, a strain gauge is provided in the above-described yarn path, an upper yarn tension waveform with respect to the rotational phase of the sewing machine spindle is calculated based on the output, and the upper yarn tension is adjusted according to the shape of the tension waveform. An automatic thread tension sewing machine has been released.

Patent Documents 3 and 4 show a sewing machine that not only detects the tension of the upper thread by using an upper thread tension adjusting device or an upper thread tension means, but also controls the tension of the upper thread in accordance with the sewing pattern. Specifically, Patent Document 3 discloses an upper thread tension adjusting device that makes the resistance force of an upper thread clamped between a fixing plate and a thread retainer plate variable during a sewing operation by a pressing force or torque applied by an electromagnetic actuator or the like. Has been. In Patent Document 4, for the purpose of creating an embroidery product having a good texture, a sewing machine having a thread tension means for optimally adjusting thread tension is disclosed even when the width and direction of the seam constantly change. Has been. Patent Documents 3 and 4 describe a feedback control configuration that adjusts the thread tension based on the output of an upper thread tension detector (a tension detecting means in Patent Document 4) that detects the thread tension by a piezoelectric element or a detection coil. Has been.

And in patent document 5, it comprises the separate motor for each individually driving machine elements, such as a needle bar, a balance, and a cloth presser, and torque data predetermined according to the rotation angle of the motor which drives a balance A sewing machine that controls the tension of the upper thread based on the current value supplied to the motor is disclosed.

By the way, in the vicinity of the end point of the above-described thread path, in order to prevent the sewing product from being lifted when the sewing needle is raised, a pressing device for the sewing product generally called a cloth presser or an intermediate presser is attached. In patent document 6, the sewing machine which improves the press precision of a to-be-sewn material is disclosed by controlling the drive force of the motor which drives this press apparatus. Patent Document 7 discloses a sewing machine that detects the thickness and hardness of a workpiece to be sewn based on a detected value of a rotation angle or driving torque of a motor that drives an intermediate presser.

As described above, in Patent Documents 1 to 5, a sewing machine including a device for detecting or controlling the upper thread tension during the sewing operation is disclosed for the purpose of improving the quality of the sewing product such as thread breakage and thread tension caused by the upper thread tension. Yes. Further, Patent Documents 6 and 7 disclose a sewing machine that changes the operation pattern of the pressing device for the purpose of improving the quality of sewing products such as the sewing tightening accuracy due to the pressing accuracy of the sewing product by the pressing device.

JP-A-6-343784 Japanese Patent Laid-Open No. 7-662 JP 11-47479 A Japanese Patent Laid-Open No. 7-661 JP 2010-178785 A Japanese Patent Laid-Open No. 11-19358 JP 2010-131175 A

However, when the tension of the upper thread is detected by the sewing machine disclosed in Patent Documents 1 to 4, in any case, a thread tension detecting device constituted by a piezoelectric element, a strain gauge, etc., its installation jig, and wiring are used. Since it is necessary to provide the sewing machine, the manufacturing cost of the sewing machine increases. In addition, since it is necessary to calibrate changes in the sensitivity and bandwidth of the detector with aging, the maintenance cost of the sewing machine increases. In addition, when a detector is provided in the yarn path, there is a problem that the layout of the sewing machine head is restricted due to structural design restrictions such as lengthening of the yarn path and securing of installation space. Further, the sewing machine of Patent Document 5 needs to include a motor that individually drives the balance. In short, the conventional sewing machines disclosed in Patent Documents 1 to 5 have many parts to be added to the sewing mechanism when detecting the upper thread tension, which causes an increase in cost and design constraints.

On the other hand, since the sewing machines disclosed in Patent Documents 6 and 7 improve the pressing accuracy of the sewing product by changing the operation pattern of the pressing device, the sewing product quality such as the above-described sewing tightening accuracy can be improved. . However, since the behavior of the upper thread, that is, the supply amount and tension of the upper thread is not monitored, for example, if a thread breakage occurs, a seam is not formed and a sewing failure occurs. Further, the sewing operation is continued even if the thread tension or the texture is disturbed by an external factor. In the sewing machines disclosed in Patent Documents 6 and 7, when checking the quality of the sewing product such as thread tension and texture, it is necessary to check the finished condition after a series of sewing operations is completed by using an inspection device or the like. In short, the conventional sewing machine disclosed in Patent Documents 6 and 7 drives the pressing device so as to improve the quality of the sewing product such as thread tension and sewing tightening accuracy, but guarantees the quality of the formed seam. There was a problem that I could not.

The present invention has been made in view of the above, and monitors the occurrence of thread breakage while performing a sewing operation with a simple configuration with few additional parts, and further guarantees the quality of the sewing product such as thread tension and sewing tightening accuracy. An object of the present invention is to provide a sewing machine that can be used.

The sewing machine according to the present invention has a sewing needle having a needle hole through which the upper thread is inserted, a hook that entangles the upper thread and the lower thread by capturing the upper thread, and a small hole through which the upper thread is inserted, A balance that pulls the upper thread from the sewing object to be sewn by raising the small hole from the bottom dead center to the top dead center, an intermediate presser that prevents the sewing product from being lifted, and a drive source that drives the intermediate presser The upper thread tension is monitored based on the load applied from the upper thread to the intermediate presser when the upper thread comes into contact with the intermediate presser when the transfer means transfers the sewing product. A tension monitoring unit.

According to the present invention, the tension applied to the upper thread can be detected via the intermediate presser, and the sewing operation is performed and the thread breakage and the sewing tightening accuracy related to the quality of the sewing product are detected with a simple configuration with few additional parts. be able to.

1 is a perspective view showing the overall configuration of a sewing machine according to Embodiment 1. FIG. The perspective view which shows the detail of the conveyance mechanism of the sewing machine which concerns on Embodiment 1. FIG. The perspective view which shows the sewing mechanism of the sewing machine which concerns on Embodiment 1. FIG. The perspective view which shows the detail of the intermediate press drive mechanism of the sewing machine which concerns on Embodiment 1. FIG. The perspective view which shows the upper thread | yarn path | route of the sewing machine which concerns on Embodiment 1. FIG. Block diagram showing a control configuration of the sewing machine according to the first embodiment Image diagram showing the operation of a general electronic sewing machine FIG. 3 is an image diagram illustrating a tension detection operation of the sewing machine according to the first embodiment. Timing chart showing operation pattern of sewing machine and intermediate presser of general electronic sewing machine and sewing machine according to embodiment 1 Timing chart showing operation of sewing machine according to Embodiment 1 FIG. 3 is a block diagram showing details of the PF shaft motor control calculation unit of the sewing machine according to the first embodiment. The block diagram which shows the detail of the PF axis deviation suppression part of the sewing machine which concerns on Embodiment 1. FIG. FIG. 3 is a block diagram showing details of a tension monitoring unit of the sewing machine according to the first embodiment. Timing chart showing the operation of the sewing machine according to the second embodiment An image diagram showing a problem of tension detection operation of the sewing machine according to the third embodiment Timing chart showing the operation of the sewing machine according to the third embodiment FIG. 9 is a block diagram showing details of a PF shaft motor control calculation unit of a sewing machine according to a fourth embodiment. FIG. 9 is a block diagram showing details of the PF axis deviation suppressing unit of the sewing machine according to the fourth embodiment. The figure which shows the 1st hardware structural example of the control panel of the sewing machine which concerns on Embodiment 1-4. The figure which shows the 2nd hardware structural example of the control panel of the sewing machine which concerns on Embodiment 1-4.

Hereinafter, a sewing machine according to an embodiment of the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
In the first embodiment, an example of a configuration of an industrial electronic sewing machine that performs a sewing operation while moving a workpiece to be sewn, such as cloth or leather, using a conveyance device such as an XY table will be described. However, as long as the sewing machine is equipped with a pressing device such as a cloth presser or an intermediate presser and is capable of transporting the sewing object so that the upper thread is in contact with the pressing device, for example, a general sewing machine, a professional sewing machine, a household sewing machine The configuration example of the present embodiment can be applied even to a sewing machine or an embroidery machine.

First, a configuration example of the sewing machine 100 according to the present embodiment will be described based on FIGS. 1 to 5. However, in FIGS. 1 to 5, in the XYZ coordinates of the right hand system, the direction in which the sewing needle moves up and down is the Z-axis direction, the direction orthogonal to the Z-axis direction is the X-axis direction, and the Z-axis direction and the X-axis direction are The direction orthogonal to both is the Y-axis direction. The X-axis direction is equal to the longitudinal direction of the bed described later.

 The main part of the sewing machine 100 shown in FIG. 1 includes a housing mechanism P0, a transport mechanism P1 shown in detail in FIG. 2, a control device P2, and a sewing mechanism P3 shown in FIG.

As shown in FIG. 1, the housing mechanism P0 of the sewing machine 100 includes an arm 101 for storing an upper shaft included in the sewing mechanism P3 of FIG. 3, and a main shaft motor case 102 for storing a main shaft motor connected to the upper shaft. A sewing machine head 103 on which the sewing mechanism P3 performs a sewing operation at the tip of the arm 101, a bed 104 for storing the XY stage included in the transport mechanism P1, and a support leg 105 for supporting the arm 101 and the bed 104 from the installation floor. And a sliding plate 106 that is fixed to the upper surface of the bed 104 and supports the holding device 112 included in the transport mechanism P1 slidably on a plane.

The housing mechanism P0 is a high-rigidity steel plate or casting shaped material designed to withstand mechanical destruction due to an impact when the sewing machine 100 operates, or a flexible material that disperses and absorbs the impact. Configure.

In FIG. 1, in order to explicitly show the arrangement of the spindle motor, the spindle motor case 102 is configured to be connected to one end of the arm 101, but the spindle motor 201 of FIG. 3 is installed inside the arm 101. Also good. 3 may be installed so as to be integrated with the sewing machine head 103, not inside the arm 101.

As shown in FIG. 1, the transport mechanism P <b> 1 of the sewing machine 100 includes an XY stage 111 and a holding device 112. The XY stage 111 is driven in the X-axis direction and the Y-axis direction by the X-axis motor 113 and the Y-axis motor 114 in FIG. 2, respectively, and the holding device 112 connected to the movable part of the XY stage 111 is placed on the horizontal plane of the sliding plate 106. Transport.

In the present embodiment, the X-axis motor 113 and the Y-axis motor 114 are servo motors mounted on the side surfaces of the bed 104, and drive the X-axis drive mechanism 115 and the Y-axis drive mechanism 116, respectively. As shown in detail in FIG. 2, the XY stage 111 includes a holding device 112 connected to a movable portion of the XY stage 111 using the X-axis motor 113 and the Y-axis motor 114 as drive sources in the X-axis direction and the Y-axis direction, respectively. It is conveyed in a horizontal plane on the sliding plate 106. The X-axis drive mechanism 115 uses the moving race 115a connected to the holding device 112 as a movable portion, and the Y-axis drive mechanism 116 uses the Y-axis guide 116a connected to the holding device 112 as a movable portion.

Rotation information detectors 117 and 118 for detecting rotation information such as the angle and angular velocity of the rotor with respect to the stator are attached to the X-axis motor 113 and the Y-axis motor 114, respectively. In the present embodiment, the rotation information detectors 117 and 118 are described as optical encoders that detect the angle of the rotor with respect to the stator. The angular velocity and angular acceleration of the rotor are obtained by differentiating the detected angle signal.

The holding device 112 connected to the XY stage 111 includes a presser base 112a, a feed plate 112b, an outer presser 112c, and an air cylinder 112d. The presser base 112a is connected to the moving race 115a, the Y-axis guide 116a, and the XY stage 111 side, and the slide plate 106 side at the other end is connected to the feed plate 112b and the outer presser 112c. The feed plate 112 b is disposed on the upper surface of the sliding plate 106 and moves slidably on the sliding plate 106 as the XY stage 111 is driven. A workpiece to be sewn by the sewing machine 100 is disposed between the feed plate 112b and the outer presser 112c. The outer presser 112c presses the feed plate 112b vertically downward to hold the holding device 112. Held by.

The holding device 112 performs switching between holding and non-holding of the sewing product using the air cylinder 112d as a drive source. The holding device 112 performs a transport operation for holding and transporting the sewing product so that the insertion position of the sewing needle with respect to the sewing product is a specific position designated by the user of the sewing machine 100.

In this embodiment, the air pressure is adjusted using the air cylinder 112d in order to secure the holding force of the holding device 112, but the invention is not limited to this, and the workpiece is held using an electromagnetic press or a hydraulic press. You may do it. Further, the structure of the transport mechanism P1 is not limited to that shown in FIG. The upper thread tension detection method shown in the embodiment can be applied. In FIG. 2, the X-axis drive mechanism 115 and the Y-axis drive mechanism 116 are constituted by belt pulley mechanisms, but the present invention is not limited to this, and a ball screw mechanism or a ball spline mechanism may be used. Further, the drive source of the XY stage 111 is not limited to the rotating electrical machine, and a plurality of linear motors, planar motors, spherical motors, and the like may be used.

The control device P2 of the sewing machine 100 includes an operation panel 121, a control panel 122, and a foot switch 123. A user of the sewing machine 100 gives a sewing command signal for driving the sewing machine 100 from the operation panel 121 to the control panel 122 based on sewing data such as sewing pattern data created on the operation panel 121. The control panel 122 controls the conveyance work by the conveyance mechanism P1, and further controls the speed and timing of the sewing work by the sewing mechanism P3 described later. The foot switch 123 includes an operation start signal for starting a sewing operation by the sewing machine 100 when a user of the sewing machine 100 presses a button, a touch panel, or the like, and holding and non-holding of a sewing object by the holding device 112. A holding signal for switching is output to the control panel 122. The operation of the control device P2 will be described after the details of the sewing mechanism P3 are described.

Next, details of the sewing mechanism P3 of the sewing machine 100 according to the present embodiment will be described with reference to FIGS. As shown in FIG. 3, the sewing mechanism P3 includes a sewing needle 131 having a needle hole, a hook 132 that catches the upper thread and entangles the upper thread and the lower thread, and pulls the upper thread from the sewing product. A balance 133 for sewing the seam to be formed, a sewing needle 131, a hook 132, a spindle motor 134 as a driving source for driving the balance 133, an intermediate presser 135 for preventing the sewing product from being lifted, and an intermediate presser 135 An intermediate presser motor 136 serving as a drive source. The sewing mechanism P3 includes a pretension 162 and a main tension 163 that adjust the tension of the upper thread, as shown in FIG.

The sewing needle 131 has a needle hole 131a through which an upper thread, which is an upper thread when a seam is formed, and moves up and down in the Z-axis direction using a spindle motor 134 as a drive source. The sewing needle 131 descends from the top dead center, reaches the bottom dead center after being inserted into the sewing product, and then the sewing product 131 while the sewing needle 131 rises from the bottom dead center toward the top dead center. The needle is pulled out from. The sewing needle 131 cooperates with the hook 132 after reaching the bottom dead center until the needle is removed from the sewing product, and when the seam is formed, a lower thread that becomes a lower thread of the sewing product is formed. The upper thread is entangled. Thereafter, the needle hole 131a of the sewing needle 131 is withdrawn from the sewing product, whereby the upper thread is pulled out to the upper surface of the sewing product.

A rotation information detector 137 that detects rotation information such as the angle and angular velocity of the rotor with respect to the stator is attached to the spindle motor 134. In the present embodiment, the rotation information detector 137 is described as an optical encoder that detects the angle of the rotor with respect to the stator of the spindle motor 134. The main shaft motor 134 is fixed to the arm 101, and one end of a shaft-shaped upper shaft 139 is connected to the rotor of the main shaft motor 134 via a coupling 138.

The rotational movement of the upper shaft 139 is converted into the vertical movement of the needle bar 142 via the balance driving mechanism 140 and the needle bar driving mechanism 141 attached to the other end of the upper shaft 139 to which the coupling 138 is not connected. . A sewing needle 131 is attached to the tip of the needle bar 142, and the sewing needle 131 moves up and down in the Z-axis direction as the needle bar 142 moves up and down. The needle bar drive mechanism 141 that moves the sewing needle 131 up and down using the main shaft motor 134 as a drive source includes a needle bar crank, a connecting bar, a needle bar hug, and the like. Other explanations using etc. are omitted.

The hook 132 includes an outer hook having a sword, a bobbin around which a lower thread is wound, and a bobbin case 143 that houses the bobbin so that the bobbin does not fall out of the outer hook. In the present embodiment, a case where a full rotation hook is adopted as the hook 132 is shown, but the present invention is not limited to this. For example, the hook 132 may be half-turned, and there is no problem whether it is horizontal or vertical.

The hook 132 uses a spindle motor 134 as a drive source. In FIG. 3, an upper shaft pulley 144 is concentrically mounted on the upper shaft 139 in the vicinity of one end of the upper shaft 139 and the coupling portion 138, and the upper shaft pulley 144 on the driving side is connected to the timing belt 145. The lower shaft pulley 146 on the driven side is rotated via The lower shaft pulley 146 rotates the large diameter gear 147 via the shaft, and rotates the small diameter gear 148 that meshes with the large diameter gear 147. With this configuration, the shaft-shaped lower shaft 149 connected to the small-diameter gear 148 rotates at a speed twice that of the upper shaft 139. The hook 132 and the lower shaft 149 are connected to the lower shaft 149 at the shaft end where the small-diameter gear 148 is not fitted, and the sewing needle 131 moves up and down as the main shaft motor 134 rotates. Rotates at twice the frequency. At this time, the sword tip of the hook 132 is moved to the top dead center after the sewing needle 131 is lowered and inserted into the sewing product and reaches the bottom dead center. The loop formed by the upper thread passed through the needle hole is captured. Since the configuration of the full rotation shuttle is a well-known technique, other description using an enlarged view or the like is omitted.

The balance 133 is connected to a balance driving mechanism 140 constituted by a crank and a balance rod using a spindle motor 134 as a drive source. The balance 133 is a rigid body made of a metal material in the shape of a bell crank. One end is provided with a small hole 133a for inserting an upper thread, and the other end is rotated with respect to a crank connected to the upper shaft 139. Connected as possible. The bent portion in the bell crank shape is connected to the other end of a balance rod whose one end is rotatably connected to the arm 101. With this configuration, the balance 133 is driven by the upper shaft 139 that rotates in synchronization with the main shaft motor 134, and one cycle of the vertical movement of the sewing needle 131 and the balance 133 becomes equal. The small hole 133a of the balance 133 is normally driven to reach the top dead center when the rotation angle of the spindle motor 134 is delayed by about 60 degrees from the top dead center of the sewing needle 131. Since the configuration of the balance driving mechanism 140 for driving the balance 133 is a well-known technique, other description using an enlarged view and the like is omitted.

Next, the drive mechanism of the intermediate presser 135 according to the present embodiment will be described with reference to FIG. The intermediate presser 135 is connected to the intermediate presser drive mechanism 151 by using an intermediate presser motor 136 including the rotation information detector 150 as a drive source. The intermediate press drive mechanism 151 drives a PF (Pressure Foot) shaft of the sewing machine 100. The intermediate presser motor 136 includes a rotation information detector 150 and detects the angle or speed of the rotor with respect to the stator of the intermediate presser motor 136. In the present embodiment, the rotation information detector 150 is described as an engineering encoder that detects the angle of the rotor with respect to the stator.

The intermediate press drive mechanism 151 includes a pinion 152, a rack 153, a slide guide 154, a slider 155, an intermediate press bar holding 156, and an intermediate press bar 157.

In the present embodiment, the intermediate presser motor 136 is a servo motor fixed to the arm 101, and a small circular hole provided at the center of a pinion 152 having a small-diameter circular gear shape is fitted to the rotor thereof. Yes. The teeth of the pinion 152 mesh with the teeth of the rack 153 and convert the rotational movement of the intermediate presser motor 136 into the translational movement of the rack 153. The rack 153 is coupled to the slider 155, and the slider 155 is guided by the slide guide 154 so as to move up and down slidably in the Z-axis direction. An intermediate presser bar holder 156 is fastened to the slider 155 with bolts, and an intermediate presser bar 157 is inserted into the intermediate presser bar holder 156 and compacted. The intermediate presser 135 is attached to the tip of the intermediate presser bar 157, and the intermediate presser bar 157 moves up and down in the Z-axis direction to drive the intermediate presser 135 in the vertical direction. A circular through hole 135a is provided at the tip of the intermediate presser 135, and a sewing needle is inserted into the through hole 135a. By configuring in this way, the sewing machine 100 controls the rotation of the intermediate presser motor 136 to drive the height of the intermediate presser 135 independently of the other sewing mechanisms.

In the present embodiment, a rotary servo motor, that is, a rotating electric machine having an annular stator and a cylindrical rotor is used as the intermediate presser motor 136, and the rotary motion of the rotor is controlled by the rack and pinion. Convert to translational motion. However, the drive source of the intermediate press 135 is not limited to a rotating electric machine such as a servo motor or a stepping motor, and may be an actuator that directly realizes translational drive such as a linear motor or a voice coil motor. By using these, it is possible to reduce power transmission loss due to the rack and pinion mechanism. Further, since the influence of backlash and friction is reduced by simplifying the mechanism, the external force that the intermediate presser 135 receives from the outside can be easily grasped from the behavior of the actuator.

Next, based on FIGS. 5A and 5B, a sewing mechanism related to the control of the upper thread path and tension of the sewing machine 100 will be described. FIG. 5A is an overall view showing the entire upper thread path in the sewing machine 100, and FIG. 5B is an enlarged view showing the upper thread path in the sewing machine head 103.
The user of the sewing machine 100 sews the upper thread T, which is the upper thread when the seam is formed, from the thread winding 159 that is the supply source of the upper thread T to the consuming part before performing the sewing operation with the sewing machine 100. Supply along the upper thread path to the needle 131. The upper thread path starts from the thread winding 159 raised on the thread winding stand 158, and the upper thread guides 160 and 161, the pretension 162, the main tension 163, the small hole 133a of the balance 133, and the upper thread guides 164, 165, Through the order of 166, the needle hole 131a provided at the tip of the sewing needle 131 is the end point. Since the sewing needle 131 is inserted through the through hole 135a provided in the cylindrical portion of the intermediate presser tip, the upper thread T inserted through the needle hole 131a is also inserted into the through hole 135a. The upper thread guides 160, 161, 164, 165, and 166 are through holes through which the upper thread T is inserted, and guide the upper thread T along the arm 101 so that the upper thread T is not tangled or unwound. The tension of the upper thread T is applied by a spring that is a component of the pretension 162 and the main tension 163 and a plate that holds the thread.

Next, the control configuration of the sewing machine 100 according to the present embodiment will be described with reference to FIG. FIG. 6 is a block diagram illustrating a control configuration of the sewing machine according to the first embodiment. A control panel denoted by reference numeral 122A corresponds to the control panel 122 shown in FIG.

As shown in FIG. 6, the operation panel 121 of the sewing machine 100 includes a display 121a, a processor 121b, a storage device 121c that stores sewing pattern data D1, and an input device 121d. The user of the sewing machine 100 inputs the sewing pattern data D1 for each stitch by operating the input device 121d configured by a push button or a touch panel while referring to the display 121a. As a result, the sewing pattern data D1 is stored in the storage device 121c. The operating system of the operation panel 121 is operated by the processor 121b. By using the sewing pattern data D1 stored in the storage device 121c, the sewing pattern can be easily created, edited, and duplicated.

The sewing pattern data D1 created on the operation panel 121 is converted into a sewing command signal by the processor 121a and transmitted to the command generation unit 1A1 of the control panel 122A. The sewing pattern data D <b> 1 is data that determines the position and shape of the seam formed on the sewing product and the operating speed of the sewing machine 100. Signal transmission between the operation panel 121 and the control panel 122A is performed via a communication circuit (not shown).

The display 121a of the operation panel 121 receives the tension monitoring signal output from the PF-axis motor control calculation unit 1A3 of the control panel 122A, and detects the occurrence of thread breakage based on the tension monitoring signal and forms the same stitch. If the needle thread tension fluctuates for each stitch in spite of this, the fact that a sewing failure has occurred is displayed to the user of the sewing machine 100.

The display device 121a is not limited to the one provided inside the operation panel 121, and may be a display device such as a liquid crystal panel or a traffic light that exists outside the operation panel 121. In this case, communication between the display and the control panel 122A may be either wired communication or wireless communication. Further, the display device 121a may be included in the control panel 122A. Similarly, the storage device 121 c is not limited to the one provided inside the operation panel 121, and a storage device existing outside the operation panel 121 can be used. In this case, communication between the storage device and the control panel 122A may be either wired communication or wireless communication.

As shown in FIG. 6, the control panel 122A for controlling the sewing machine 100 includes at least a command generation unit 1A1, a spindle motor control calculation unit 1A2, a PF axis motor control calculation unit 1A3, an X axis motor control calculation unit 1A4, Y-axis motor control calculation unit 1A5. In addition to these, a solenoid that performs thread trimming when the sewing operation is completed, a notification sensor that notifies that the thread has run out, a control circuit that drives a position sensor for the transport mechanism P1 to perform home return, and a power supply circuit are provided. In some cases, these are not directly related to the effects of the present invention, and thus the description thereof is omitted.

The control panel 122A includes a sewing command signal output from the processor 121b of the operation panel 121, a holding signal and an operation start signal output from the foot switch 123, and a spindle motor output from the rotation information detector 137 of the spindle motor 134. The main shaft rotation signal which is rotation information of 137, the PF axis rotation signal which is rotation information of the intermediate presser motor 136 output from the rotation information detector 150 of the intermediate presser motor 136, and the rotation information detector 117 of the X-axis motor 113. The X-axis rotation signal, which is the rotation information of the X-axis motor 113 output from the Y-axis, and the Y-axis rotation signal output from the rotation information detector 118 of the Y-axis motor 114 are input.

Based on these input signals, the control panel 122A, the spindle control current that drives the spindle motor 134, the PF axis control current that drives the intermediate presser motor 136, the X axis control current that drives the X axis motor 113, A Y-axis control current for driving the Y-axis motor 114, a holding command signal for driving the air cylinder 112d, and a tension monitoring signal output from the PF-axis motor control calculation unit 1A3 are output.

The command generation unit 1A1 of the control panel 122A receives the sewing command signal output from the processor 121b of the operation panel 121, the holding signal and the operation start signal output from the foot switch 123, and receives the spindle command signal, PF An axis command signal, an X-axis command signal, a Y-axis command signal, and a holding command signal are output. The spindle command signal, the PF axis command signal, the X axis command signal, and the Y axis command signal indicate the rotation angles of the spindle motor 134, the intermediate presser motor 136, the X axis motor 113, and the Y axis motor 114, respectively. This electric signal is designated and is calculated inside the command generator 1A1 according to the sewing pattern data D1.

The holding signal output from the foot switch 123 is an electric signal that specifies the pressure of the air cylinder 112d so that the workpiece is held by the feed plate 112a and the outer presser 112b of the holding device 112. The operation start signal output from the foot switch 123 is transmitted from the command generator 1A1 to the spindle command signal, the PF axis command signal, the X axis command signal, and the Y axis command signal, respectively, to the spindle motor control calculation unit 1A2. It is an electrical signal that specifies the timing to start transmission toward the PF-axis motor control calculation unit 1A3, the X-axis motor control calculation unit 1A4, and the Y-axis motor control calculation unit 1A5.

The spindle motor control calculation unit 1A2 of the control panel 122A receives the spindle command signal and the spindle rotation signal, and outputs a spindle control current that rotates the spindle motor 134 so that the difference between the spindle command signal and the spindle rotation signal becomes zero. .

The PF axis motor control calculation unit 1A3 of the control panel 122A receives the PF axis command signal and the PF axis rotation signal as input, and rotates the intermediate presser motor 136 so that the difference between the PF axis command signal and the PF axis rotation signal becomes zero. PF axis control current is output. Further, the PF shaft motor control calculation unit 1A3 monitors the tension of the upper thread during the period when the small hole 133a of the balance 133 rises as the main shaft motor 134 rotates, and outputs an upper thread tension monitoring signal. That is, the sewing machine 100 according to the present invention is configured such that the PF shaft motor control calculation unit 1A3 monitors the needle thread tension.
The X-axis motor control calculation unit 1A4 of the control panel 122A receives the X-axis command signal and the X-axis rotation signal as inputs, and rotates the X-axis motor 113 so that the difference between the X-axis command signal and the X-axis rotation signal becomes zero. Outputs X-axis control current.

The Y-axis motor control calculation unit 1A5 of the control panel 122A receives the Y-axis command signal and the Y-axis rotation signal and rotates the Y-axis motor 114 so that the difference between the Y-axis command signal and the Y-axis rotation signal becomes zero. Outputs Y-axis control current.

Next, an operation in which the sewing machine 100 forms a seam will be described. First, the user of the sewing machine 100 supplies the upper thread T from the thread winding 159 to the needle hole 131a along the above-described upper thread path. On the other hand, the lower thread Td, which is the lower thread when the seam is formed, is wound around the bobbin stored in the bobbin case 143 of the hook 132.

When the foot switch 123 is pressed by the user of the sewing machine 100 and a holding signal is sent to the command generation unit 1A1 of the control panel 122A, the air cylinder 112d is operated by the holding command signal output from the command generation unit 1A1, The workpiece is held by the holding device 112 shown in FIG. 1 so that it can be conveyed. Thereafter, when the foot switch 123 is further pressed and an operation start signal is sent to the control panel 122A, the X-axis motor 113 and the Y-axis motor 114 that are the drive sources of the transport mechanism P1, and the spindle that is the drive source of the sewing mechanism P3. The motor 134 and the intermediate presser motor 136 are operated, and the sewing machine 100 starts to form a seam at a specific position of the sewing product that is specified in advance by the user of the sewing machine 100 using the operation panel 121. In this way, when the spindle motor control operation unit 1Ab of the control panel 122A rotates the spindle motor 134, the sewing needle 131 having the upper thread T passed through the needle hole 131a is directed from the upper side to the lower side of the sliding plate 106. The needle is inserted into the workpiece. By the operation of the sewing needle 131, the upper thread T is supplied to the lower side of the sewing product. Thereafter, when the sewing needle 131 rises from the bottom dead center, the upper thread T forms a loop on the lower side of the sewing product due to friction with the sewing product.

The tip of the hook 132 catches the upper thread at the timing when the loop of the upper thread T is formed, and entangles the upper thread and the lower thread. The timing at which the sword tip of the hook 132 catches the upper thread is generally 190 ° to 210 ° when the rotation angle of the spindle motor when the sewing needle is located at the top dead center is 0 °. Set within range. After the upper thread and the lower thread are intertwined, the sewing needle 131 is removed from the sewing product, whereby the upper thread is pulled out to the upper surface of the sewing product. Then, when the balance 133 pulls the upper thread upward to the workpiece, the upper thread T is tightened to form a seam. At this time, the intermediate presser 135 presses the sewing object so that the sewing object does not float or flutter as the sewing needle 131 and the balance 133 are raised.

The pretension 162 and the main tension 163 always apply a constant tension to the upper thread during the period when the sewing machine 100 forms the seam.

Next, an operation for detecting the upper thread tension of the sewing machine 100 according to the first embodiment of the present invention will be described with reference to FIGS.

First, based on FIG. 7 to FIG. 9, the characteristics of the operation when the sewing machine 100 according to the present embodiment detects the upper thread tension as compared with the operation of a general electronic sewing machine will be described.

FIGS. 7 and 8 show a sewing machine when the sewing needle descends from the top dead center to the bottom dead center and moves to the top dead center again in the general electronic sewing machine and the sewing machine 100 according to the present embodiment. The positional relationship between the presser and the workpiece and the stitches formed are shown. In both figures, the stitches up to the (N-1) th stitch have already been formed, and thereafter, the sewing needle is lowered to perform the Nth stitch sewing operation.

FIG. 9 is a timing chart depicting a driving locus of a sewing needle and an intermediate presser in a general electronic sewing machine and the sewing machine 100 of the present invention. The timing a indicated by the broken line in FIG. 9 is at the top dead center of the sewing needles 131 ′ and 131 in the sewing operation of the (N-1) th stitch, the timing b is when the sewing needles 131 ′ and 131 are inserted, and the timing c is the sewing needle. At the bottom dead center of 131 'and 131, timing d is the rotation angle of the spindle motor when the knot loops the upper thread loop, and timing e is the rotation angle of the spindle motor when the sewing needles 131' and 131 are withdrawn. Similarly, timings a ′ to e ′ represent timings when the sewing machine 100 performs the Nth stitch sewing operation. 7 and 8 show an operation state when the rotation angle of the spindle motor is the timing a ′ in the timing chart of FIG. 9. The black circle (●) mark in the upper part of FIG. 9 explicitly indicates the position of the sewing needle at the timing d when the hook hits the upper thread loop.

As shown in the upper part of FIG. 9, the sewing needles 131 ′ and 131 move up and down with a stroke lh. Further, as shown in the middle and lower stages of FIG. 9, the intermediate pressers 135 ′ and 135 move up and down with a stroke lo. However, the middle and lower waveforms in FIG. 9 show the driving waveform of the bottom surface of the intermediate presser 135, and the intermediate presser 135 has a timing e when the sewing needles 131 ′ and 131 are removed from the sewing product and inserted again. To b ′, the bottom surface of the intermediate presser 135 is driven so as to stop at a position raised by a distance dlo from the workpiece. The distance dlo is at least longer than the diameter of the upper thread T so that the upper thread T can pass between the intermediate presser 135 and the sewing object Ob.

In FIG. 7, the intermediate presser 135 'of a general electronic sewing machine is driven in a sine wave shape almost in phase with the drive locus of the sewing needle 131'. For this reason, when the sewing needle 131 ′ is located at the top dead center, it is located at a position farther from the sewing object Ob ′ than in FIG. 8. More specifically, as shown by the white circle (○) in the middle of FIG. 9, the intermediate presser 135 ′ of a general electronic sewing machine is sewn at the timing d when the tip of the rotary hook hits the loop of the upper thread. It is driven by a sinusoidal trajectory so as to press an object. In particular, when the intermediate press 135 ′ is a general electronic sewing machine and the main shaft motor is used as a drive source, it is difficult to realize the drive pattern of the intermediate press as shown in the lower part of FIG. On the other hand, in FIG. 8, since the intermediate presser 135 is driven independently by the intermediate presser motor 136, when the sewing needle 131 is positioned at the top dead center at the timing a ', the intermediate presser 135 is separated from the sewing object Ob. It can be stopped at a position separated by dlo.

Incidentally, in the upper thread T ′ or the upper thread T, a tension is generated between the workpiece Ob ′ and the small hole as the small hole of the balance rises. The main object of the present invention is to guarantee the quality of the sewing product by detecting the magnitude of the tension based on the behavior of the intermediate presser motor 136 during the sewing operation without adding a dedicated detector. Therefore, the sewing machine 100 according to the present invention drives the transport mechanism P1 that holds the sewing object Ob so that the upper thread T and the intermediate presser 135 are in contact with each other. Then, as shown in FIG. 8, the upper thread T ′ is higher than the upper thread T ′ by stopping the intermediate presser 135 at a position separated by the distance dlo from the sewing object Ob during the period when the small hole of the balance is raised. This increases the influence of the load on the intermediate presser motor 136.

Next, a sewing operation and a conveying operation when the sewing machine 100 according to the present embodiment detects the upper thread tension will be described with reference to FIG.

FIG. 10 shows the driving of the driven body after the (n−1) th stitch when the sewing machine 100 repeatedly performs the sewing operation of n stitches or more (n ≧ 3) on the sewing object Ob on the upper surface of the sliding plate 106. Waveform is shown. More specifically, in this figure, in order from the top, the position of the needle hole 133a of the sewing needle 131, the rotation angle of the sword tip of the hook 132, the position of the intermediate presser 135, the position of the small hole 133a of the balance 133, and the transport mechanism P1 A position in the X-axis direction of the workpiece to be conveyed and a position in the Y-axis direction of the workpiece to be conveyed by the conveying mechanism P1 are shown.

First, as shown in the uppermost part of FIG. 10, the needle hole 131a of the sewing needle 131 that uses the spindle motor 134 as a driving source draws the same locus as in FIG. 9, and the top dead center at timing a and the workpiece to be sewn at timing b. The needle is inserted at the bottom dead center at timing c and the needle is pulled out at the timing e. Timing d is when the tip of the hook 132 hits the upper thread loop, and a black circle (●) mark explicitly indicates the position of the sewing needle 131 at this time. Similarly to FIG. 9, the stroke of the sewing needle 131 is lh.

Next, the second stage from the top in FIG. 10 shows the rotation angle of the hook 132 using the spindle motor 134 as a drive source, and the drive waveform of the hook 132 is a sine wave with an amplitude lk. In the present embodiment, since a full rotation hook is employed, the rotation waveform of the hook 132 has a frequency twice that of the position waveform of the sewing needle 131. The black circle (●) mark in the figure explicitly indicates the rotation angle of the hook 132 when the tip of the hook 132 crawls the loop formed in the upper thread. The upper thread T captured by the sword tip of the hook 132 is released from being captured by the hook 132 at a timing i when the hook 132 counts from the rotation angle a and makes one and a half revolutions.

Next, the third row from the top in FIG. 10 is a position waveform of the small hole 133a of the balance 133 using the spindle motor 134 as a drive source. The small hole 133a of the balance 133 is driven so that one rotation of the spindle motor 134 is one cycle, and the spindle motor 134 is at the top dead center when the timing is h, and is the bottom dead center at the timing i. Timing h is determined by mechanically adjusting the rotation center at which the balance driving mechanism 140 swings, so that the sewing needle 131 is inserted into the sewing object Ob after the spindle motor 134 starts to rotate, that is, the spindle. It is designed so that the rotation angle of the motor 134 exists between a and b. In the present embodiment, the timing h is an angle obtained by rotating the spindle motor 134 by 60 degrees from the timing a.

On the other hand, the timing i at which the small hole 133a becomes the bottom dead center is a timing at which the rotation angle of the hook 132 is half a rotation from a. This is because the upper thread supplementation by the rotary hook 12 starts to be released at the rotation angle i of the spindle motor 134. If the small hole 133a is pulled up before the upper thread is supplemented by the hook 132, the upper thread T cannot withstand the tension generated when the balance 133 is lifted, and the upper thread is released. The problem is that the thread breaks. In the present embodiment, the timing i is an angle obtained by rotating the spindle motor 134 by 270 degrees from the timing a. Accordingly, the small hole 133a of the balance 133 is in the sewing operation of the (N-1) th stitch, descends in the period td from the timing h to the timing i, and in the period tu from the timing i to the timing h ′ of the Nth stitch. To rise. There is a relationship of td> tu between the period td and the period tu.

Next, the fourth level from the top of FIG. 10 shows the position of the bottom surface of the intermediate presser 135 using the intermediate presser motor 136 as a drive source, as in the lowermost level of FIG. The intermediate presser 135 starts to descend from the top dead center due to the rotation of the intermediate presser motor 136, and then until the timing b when the sewing needle 131 is inserted into the sewing product Ob, the upper surface of the sewing product Ob. Drive to abut. When the sewing object Ob is made of a non-stretchable material, the intermediate presser 135 presses the sewing object Ob at a height when the intermediate presser 135 descends and comes into contact with the sewing object Ob. In this case, the bottom dead center of the intermediate presser is the height when the bottom surface portion of the intermediate presser 135 comes into contact with the sewing object Ob, and the intermediate presser 135 moves up and down with a stroke lo from the top dead center to the bottom dead center. To do.

When the sewing object Ob is made of a material having high stretchability, the intermediate presser 135 presses the sewing object Ob at a height at which the intermediate presser 135 is lowered and the sewing object Ob is compressed. In this case, the bottom dead center of the intermediate presser is a height when the sewing object Ob is compressed. The intermediate presser 135 starts to press the sewing object Ob before the sewing needle 131 is inserted into the sewing object Ob, and rises from the sewing object Ob by the distance dlo after the sewing needle 131 is pulled out. .

Next, the fifth row from the top in FIG. 10 is a position waveform in the X-axis direction of the holding device 122 driven by the X-axis motor 113. Since the holding device 122 holds the sewing object Ob, this position waveform is equal to the position waveform of the sewing object Ob in the X-axis direction. The symbol lx in the figure is the movement distance of the holding device 122 that moves in the X-axis direction between one needle. The holding device 122 is stationary while the sewing needle 131 is inserted into the sewing object Ob so as not to damage the sewing object Ob or cause the needle to be broken, and the sewing needle 131 moves away from the sewing object Ob. After the needle is removed, it is driven until the needle is inserted into the sewing object Ob again.

In the present embodiment, in order to detect the upper thread tension when the balance is raised from the behavior of the intermediate presser motor, the XY stage 111 is set so that the upper thread T contacts the intermediate presser 135 while the small hole 133a of the balance 133 is raised. Drive. For this reason, the X-axis motor 113 is driven between the timing e when the sewing needle 131 is withdrawn from the sewing object Ob and the timing i when the small hole 133a starts to rise. Therefore, the X-axis motor 113 rotates in the period tm from the timing e to the timing i at the (N−1) th stitch, and stops in the period ts from the timing i to the timing e ′ at the Nth stitch.

Next, the sixth row from the top in FIG. 10 is a position waveform in the Y-axis direction of the holding device 122 driven by the Y-axis motor 114. Since the holding device 122 holds the sewing object Ob, this position waveform is equal to the position waveform of the sewing object Ob in the Y-axis direction. The symbol ly in the figure is the movement distance of the holding device 122 that moves in the Y-axis direction between one needle. In the present embodiment, the Y-axis motor 114 is driven with the same position waveform as the X-axis motor 113.

When the workpiece Ob is driven by lx and ly in the X-axis direction and the Y-axis direction, respectively, the movement distance L of the XY stage 111, that is, the stitch pitch is obtained by the following formula 1.

Further, if the bottom surface of the through hole 135a of the intermediate presser 135 is a circle having a radius r, and the sewing needle 131 moves up and down at the center of the through hole 135a, and the moving distance L is larger than the radius r, the intermediate presser 135 and The XY stage can be driven so that the upper thread T comes into contact.

In addition, the influence of the load which the upper thread T exerts on the intermediate presser motor 136 can be increased by reducing the angle θ formed by the sewing object Ob and the upper thread T shown in FIG. The angle θ is obtained by Equation 2.

In order to reduce the angle θ, (L−r) may be increased or the distance dlo for raising the intermediate presser may be decreased.
(Tension detection operation by PF axis motor control calculation unit 1A3)

Next, based on FIGS. 11 to 13, the configuration and operation of detecting the load applied by the tension of the upper thread T to the intermediate presser motor 136 by the PF shaft motor control calculation unit 1A3 of the control panel 122A will be described in detail.

As shown in FIG. 11, the PF shaft motor control calculation unit 1A3 of the control panel 122A is operated at the sewing operation of the PF shaft deviation suppression unit 1A3a, the current control unit 1A3b, and the sewing machine 100 for controlling the rotation of the intermediate presser motor 136. A tension monitoring unit 1A3c that monitors the yarn tension.

The PF axis deviation suppressing unit 1A3a is a PF axis command signal that is a rotation command of the intermediate presser motor 136 that is output from the command generating unit 1A1, and rotation information that is output from the rotation information detector 150 provided in the intermediate presser motor 136. A PF axis motor that drives the intermediate presser motor 136 so that the difference between the PF axis command signal and the PF axis rotation signal becomes 0 with the PF axis rotation signal and the tension monitoring signal output from the tension monitoring unit 1A3c as inputs. A drive signal is output. The current control unit 1A3b generates a PF shaft control current for rotating the intermediate presser motor 136 based on the PF shaft motor drive signal, and supplies it to the intermediate presser motor 136. The tension monitoring unit 1A3c detects the tension generated in the upper thread as the small hole 133a of the balance 133 moves up based on the PF shaft motor drive signal, and the display 121a of the operation panel 121 and the PF shaft deviation suppressing means. A tension monitoring signal is output to 1A3a.

As shown in FIG. 12, the PF axis deviation suppression unit 1A3a of the PF axis motor control calculation unit 1A3 includes a switch a1, a difference unit a2, and a deviation suppression compensator a3.

The switch a1 receives the PF axis command signal output from the command generation unit 1A1 and the tension monitoring signal output from the tension monitoring unit 1A3c, and receives thread breakage or needle thread tension while the sewing machine 100 is performing a sewing operation. When the occurrence of the variation is detected, the change of the value of the PF axis command signal is stopped based on the tension monitoring signal, and the intermediate presser motor is stopped in conjunction with the occurrence of the sewing failure. By providing the same function as that of the switch a1 with respect to the spindle command signal, the X-axis command signal, and the Y-axis command signal, the operation of the entire sewing machine may be stopped in conjunction with the occurrence of the sewing failure. By doing so, it is possible to prevent the sewing machine 100 from performing an extra sewing operation after the occurrence of a sewing failure.

The differencer a2 calculates a difference between the PF axis command signal output from the switch a1 and the PF axis rotation signal output from the rotation information detector 150, and outputs a deviation signal. The deviation suppression compensator a3 outputs a PF axis motor drive signal that drives the PF axis motor 136 so that the deviation signal converges to zero. The deviation suppression compensator a3 includes at least one of a proportional compensator that performs a proportional operation, an integral compensator that performs an integral operation, and a differential compensator that performs a differential operation in order to converge the deviation signal to 0. . In the present embodiment, it is described that PI control by a proportional compensator and an integral compensator is adopted for the deviation suppression compensator a3.

As shown in FIG. 13, the tension monitoring unit 1A3c of the PF shaft motor control calculation unit 1A3 includes a filter processing unit c1, a recording unit c2, and a comparator c3.

The filter processing unit c1 performs an operation for reducing the frequency component of the PF shaft motor drive signal that is higher than the rotation frequency of the main shaft motor 134 and a PF that is lower than the rotation frequency of the main shaft motor 134 in order to improve the detection accuracy of the needle thread tension. The evaluation signal is calculated and output by performing any one or both of the calculation for reducing the frequency component of the shaft motor drive signal. Further, the filter processing unit c1 may perform a phase filter for manipulating the phase of the PF shaft motor drive signal or a proportional calculation for changing the amplitude. By using the phase filter, the detection delay of the rotation information detector 150 and the communication delay can be corrected, and the accuracy of the tension detection time can be improved. In addition, the evaluation signal can be normalized to an arbitrary detection specification by performing a proportional calculation that changes the amplitude by multiplying the gain.

The recording unit c2 records the evaluation signal output by the filter processing unit c1 while performing the sewing operation before one stitch, and outputs the recorded evaluation signal in time so as to synchronize with the current sewing timing. That is, the recording unit c2 may be a delay computer that generates a delay corresponding to a time obtained by multiplying the time required for one stitch.

The comparator c3 is a tension monitoring signal for notifying that the rate of change of the current evaluation signal output from the filter processing unit c1 is larger or smaller than the threshold with respect to the evaluation signal one stitch before output from the recording unit c2. Is output.

For example, when forming a seam in the same direction with respect to a constant-shaped workpiece Ob, when the sewing operation and the conveying operation of the sewing machine 100 are normally performed and no sewing failure occurs, the upper thread T The tension applied to the intermediate presser motor 136 via the intermediate presser 135 is uniform. In this case, the rate of change of the evaluation signal described above is small (ideally constant). On the other hand, when the rate of change of the evaluation signal described above is large, it can be detected that the needle thread tension varies for each stitch, and that the thread tension and the sewing tightening accuracy are not constant. Further, when no load is applied from the upper thread T to the intermediate presser motor 136 and the evaluation signal is 0, the upper thread T is not in contact with the intermediate presser 135, so that occurrence of thread breakage can be detected. Thus, by setting the threshold value for the rate of change of the evaluation signal, the quality of the sewing product based on the variation in the upper thread tension can be quantitatively evaluated.

Note that the comparator c3 may calculate feature quantities such as a maximum value, a minimum value, and an average value of the input evaluation signal one stitch before and compare it with the current evaluation signal. By doing in this way, it is possible to easily grasp the change rate of the current evaluation signal with respect to one stitch before. For example, the change rate is calculated by normalizing the maximum value and the minimum value of the evaluation signal recorded in the period from the timing i of the (N-1) th stitch to the timing h ′ of the Nth stitch as 100% and 0%. It can be calculated by evaluating to what extent the maximum value and the minimum value from the timing i ′ to the timing h ″ of the (N + 1) th stitch are lowered by the comparator 703.

In addition, it is desirable to set the threshold value in consideration of the variation for each stitch caused by the sewing direction and the shape of the sewing object. Further, the operation panel 121 and the control panel 122A may be configured so that the user of the sewing machine 100 can set the threshold value from the outside of the control panel 122A by the input device 121d through a preliminary test operation by trial sewing. For example, it is possible to adopt a configuration in which the threshold value is recorded in the storage device 121c of the operation panel 121 and transmitted to the PF axis motor control calculation unit 1A3 of the control panel 121A through the processor 121b or a communication circuit (not shown). By doing so, it is possible to change the criteria for determining the quality of the sewing product in accordance with the request of the user of the sewing machine 100.

Further, the tension detector 1A3c receives the PF shaft motor drive signal as an input, but may calculate and output a tension monitor signal with the PF shaft control current or the PF shaft rotation signal as an input.

The tension detector 1A3c constitutes a disturbance observer that receives the PF shaft motor drive signal and the PF shaft rotation signal as input, and is applied to the intermediate presser motor 135 based on the mathematical model of the intermediate presser motor 136 and the intermediate presser drive mechanism. The upper thread tension may be estimated.

Further, the tension applied to the upper thread T by the pretension 162 and the main tension 163 may be controlled based on the tension monitoring signal so that the variation of the upper thread tension for each stitch is reduced.

As described above, the sewing machine 100 according to the first embodiment drives the sewing object Ob so that the upper thread T comes into contact with the intermediate presser 135, and the upper thread while the small hole 133a of the balance 133 is raised. Since the load applied to the intermediate presser motor 136 by the T through the intermediate presser 135 is detected based on the PF shaft motor drive signal, the variation of the upper thread tension applied to the upper thread due to the rise of the small hole 133a is different for each needle. Can be detected.

Therefore, the sewing machine 100 according to the first embodiment can form the seam while guaranteeing the quality of the sewing product such as the thread tension and the sewing tightening accuracy with which the quality can be determined based on the variation in the upper thread tension.

Further, since the sewing machine 100 according to the first embodiment forms the seam while assuring the quality of the sewing product for each stitch, it is possible to identify the seam where the sewing failure has occurred.

The sewing machine 100 according to the first embodiment can detect yarn breakage when no load is applied from the upper thread T to the intermediate presser motor 136.

Further, since the sewing machine 100 according to the first embodiment detects the needle thread tension based on the PF shaft motor drive signal that is the drive control signal of the intermediate presser motor 135, the sewing operation can be performed with a simple configuration with few additional parts. While performing, the occurrence of thread breakage can be monitored, and the quality of the sewing product such as thread tension and sewing tightening accuracy can be guaranteed.

Further, the sewing machine 100 according to the first embodiment is easier to secure the space around the arm portion and the ease of assembly than the case where a dedicated detector is provided in the upper thread path to detect the upper thread tension. The design freedom of the head can be expanded.

Embodiment 2. FIG.
Based on FIG. 14, the configuration and operation of the sewing machine 100 according to the second embodiment will be described. FIG. 14 is a timing chart showing the operation of the sewing machine according to the second embodiment.

The sewing machine 100 according to the second embodiment is different from the sewing machine 100 according to the first embodiment in the drive waveforms in the X-axis direction and the Y-axis direction of the holding device 112 driven by the XY stage 111 provided in the transport device P1. Other configurations and operations are the same as those of the sewing machine 100 according to the first embodiment. Explanation of similar parts is omitted.

Since the XY stage 111 according to the first embodiment drives the X-axis motor 113 from the timing e to the timing i, the rotation speed of the spindle motor 134 is high and the sewing time of one stitch is short. When the moving distance L is long, it is necessary to drive the holding device 112 with high speed and high accuracy. Thus, in order to increase the speed and accuracy of the XY stage, it is necessary to increase the rigidity of the mechanism and the output of the drive source, resulting in high costs. Therefore, in the present embodiment, the driving method of the holding device 112 is changed as follows.

As shown in the upper part of FIG. 14, the holding device 122 using the X-axis motor 113 as a drive source starts to move from timing e in the sewing operation of the (N−1) th stitch and moves to timing b ′ of the Nth stitch. Complete and stop. Therefore, the X-axis motor 113 stops in the period ts from the timing b to the timing e at the (N−1) th stitch, and rotates in the period tm from the timing e to the timing b ′ of the Nth stitch. The timing at which the holding device 122 stops may be within the period from timing e to timing b.

14 shows a position waveform in the Y-axis direction of the holding device 122 driven by the Y-axis motor 114. The Y-axis motor 114 rotates during a period tm when the X-axis motor 113 rotates.

Since the sewing machine 100 according to the second embodiment can increase the drive time of the X-axis motor 113 and the Y-axis motor 114, the rotation speed of the spindle motor 134 is high and the sewing time of one stitch is short, or the XY stage 111. Even when the moving distance L is long, the load applied by the upper thread to the intermediate presser motor 136 via the intermediate presser 135 can be detected. Therefore, even in such a case, the sewing machine 100 according to the second embodiment can detect the variation of the upper thread tension applied to the upper thread by the ascent of the small hole 133a for each stitch. The seam can be formed while guaranteeing the quality of the sewing product such as the thread tension and the sewing tightening accuracy with which the quality can be judged based on the variation in the upper thread tension.

Embodiment 3 FIG.
The configuration and operation of sewing machine 100 according to Embodiment 3 will be described based on FIGS. 15 and 16. FIG. 15 is an image diagram illustrating a problem of the tension detection operation of the sewing machine according to the third embodiment. FIG. 16 is a timing chart showing the operation of the sewing machine according to the third embodiment.

The sewing machine 100 according to the third embodiment is different from the sewing machine 100 according to the first or second embodiment in that the driving waveforms in the X-axis direction and the Y-axis direction of the holding device 112 driven by the XY stage 111 provided in the transport device P1 are different. The configuration and operation are the same as those of the sewing machine 100 according to the first or second embodiment. Explanation of similar parts is omitted.

First, a problem to be solved by the sewing machine according to the present embodiment will be described with reference to FIG. In the present embodiment, it is assumed that the diameters of the sewing needle 131 and the upper thread T are thicker than those in the first and second embodiments. Therefore, in FIG. 15, the diameters of the sewing needle 131 and the upper thread T are made larger than those in FIGS. 7 and 8, and the radius r of the through hole 135 a of the intermediate presser 135 is drawn larger.

15A and 15B show the state of timing a ′ when the sewing needle 131 is at the top dead center when the sewing machine 100 is driven based on the timing chart (FIG. 10) of the first embodiment described above. Show. In FIG. 15A, since the radius r of the through hole 135a is smaller than the movement distance L of the XY stage, when the XY stage is driven with the waveform pattern in the X axis direction and the Y axis direction shown in the timing chart of FIG. At timing a ′, the upper thread T contacts the intermediate presser 135 without any problem. Therefore, in FIG. 15A, the load applied by the upper thread T to the intermediate presser motor 136 via the intermediate presser 135 while the small hole 133a of the balance 133 is raised can be detected based on the PF shaft motor drive signal. it can.

However, since the radius r is larger than the movement distance L in FIG. 15B, even if the holding device 122 is driven with the waveform patterns in the X-axis direction and the Y-axis direction shown in the timing charts of FIGS. When the small hole 133a is raised, the upper thread T and the bottom surface portion of the intermediate presser 135 cannot be brought into contact with each other. In order to bring the upper thread T into contact with the bottom surface portion of the intermediate presser 135, it is desirable to use an intermediate presser that minimizes the radius r of the through hole 135a. However, many types of intermediate pressers are prepared and the sewing needle 131 is used. In addition, it is not efficient and there is a limit to changing to the intermediate presser having the smallest radius r according to the thickness of the upper thread T. Therefore, in the present embodiment, the drive pattern of the XY stage is changed as follows.

As indicated by the thick line in the upper part of FIG. 16, the holding device 122 using the X-axis motor 113 as the driving source forms an N-th stitch, and therefore moves in the X-axis direction from timing e in the (N−1) -th stitch conveying operation. , And the movement is completed and stopped by timing i. The moving distance lxx at this time is set larger than the radius r of the through-hole 135a so that the angle θ obtained by Equation 3 is 30 degrees or less.

Next, the holding device 122 stops the sewing object Ob so that the upper thread T comes into contact with the bottom surface portion of the intermediate presser 135 by stopping in the period ts of h ′ from the timing i when the small hole 133a of the balance 133 rises. Hold. Then, during a period from timing h ′ at which the small hole 133a finishes rising to timing b ′ at which the sewing needle 131 is inserted into the sewing object Ob, the needle moves to a predetermined position for forming the Nth stitch. Then, the holding device 122 stops in a period ts from timing b ′ when the sewing needle 131 is inserted into the sewing object Ob to timing e ′ when the needle is removed. After the timing e ′, the same operation is repeated to form (N + 1) stitches.

On the other hand, the thick line in the lower part of FIG. 16 shows the drive waveform in the Y-axis direction of the holding device 122 using the Y-axis motor 114 as a drive source. In the figure, a Y-axis motor 114 shows the same drive waveform as the X-axis motor.

Since the stitches of the (N-1) stitch and the Nth stitch are separated by 1x in the X-axis direction and ly in the Y-axis direction, the distance moved during the period from the timing h ′ to the timing b ′ is the X-axis direction (lxx −lx) and (lyy−ly) in the Y-axis direction, and the movement distance L2 of the XY stage is obtained by Equation 4.

Therefore, when the moving distance lxx in the X-axis direction is sufficiently larger than the radius r of the through hole 135a, it is not necessary to change the driving waveform of the Y-axis motor, and the moving distance lyy may be set to ly. That is, lxx and lyy may be determined so that the distance L2 obtained by Expression 5 is sufficiently larger than the radius r.

Further, when the rotational speed of the spindle motor 134 is high and the sewing time of one stitch is short, or when the movement distance L of the XY stage 111 is long, the period from timing e to i is short. For this reason, as shown by the thick broken line in FIG. 16, if the upper thread T is in contact with the bottom surface portion of the intermediate presser 135, the timing at which the holding device 122 stops within the period from the timing e to the timing h ′ is changed. You may do it.

The sewing machine 100 according to the third embodiment has a small hole even if the radius r of the through hole 135a of the intermediate presser 135 is larger than the pitch of the seam due to the thickness of the sewing needle 131 and the upper thread T. The holding device 122 is driven so that the upper thread T is in contact with the bottom surface portion of the intermediate presser 135 during the period in which 133a is raised. Therefore, even in such a case, the sewing machine 100 according to the third embodiment can detect the variation of the upper thread tension applied to the upper thread by the rise of the small hole 133a for each stitch, The seam can be formed while guaranteeing the quality of the sewing product such as the thread tension and the sewing tightening accuracy with which the quality can be judged based on the variation in the upper thread tension.

In the present embodiment, it is assumed that the through hole 135a of the intermediate presser 135 has a circular bottom surface portion with a radius r. However, when the intermediate presser in which the shape of the bottom surface portion of the through hole 135a is not circular is used. Even if it exists, quality assurance based on the means for detecting the upper thread tension according to the present invention can be implemented.

Embodiment 4 FIG.
The configuration and operation of sewing machine 100 according to the fourth embodiment will be described with reference to FIGS. FIG. 17 is a block diagram illustrating details of the PF shaft motor control calculation unit of the sewing machine according to the fourth embodiment. FIG. 18 is a block diagram showing details of the PF axis deviation suppressing unit of the sewing machine according to the fourth embodiment.

The sewing machine 100 according to the fourth embodiment is different from the sewing machine 100 according to the first to third embodiments in that data to be stored in the storage device 121c included in the operation panel 121 and the PF axis deviation suppression unit 1B3a included in the control panel 122B are different from those in the sewing machine 100 according to the first to third embodiments. Other configurations and operations are the same as those of the sewing machine 100 according to the first to third embodiments. Explanation of similar parts is omitted.

First, based on FIG. 17, data that the sewing machine 100 according to the fourth embodiment communicates between the operation panel 121 and the control panel 121B will be described. The storage device 121c of the operation panel 121 stores the parameter D2 input by the user of the sewing machine 100 using the input device 121d, and outputs the parameter D2 to the control panel 122B. The parameter D2 is transmitted to the control panel 122B via a communication circuit (not shown) based on a command from the processor 121b included in the operation panel 121. The PF axis deviation suppressing unit 1B3a of the control panel 122B receives the parameter D2 and changes the control parameter inside the PF axis deviation suppressing unit 1B3a.

Next, based on FIG. 18, the detail of PF axis | shaft deviation suppression part 1B3a is demonstrated. The PF axis deviation suppressing unit 1B3a receives the PF axis command signal, the PF axis rotation signal, the tension monitoring signal, and the parameter D2, and outputs a PF axis motor drive signal. The deviation suppression compensator a3 of the PF axis deviation suppression unit 1B3a controls the rotation of the intermediate pressing motor 136 so that the difference between the PF axis command signal and the PF axis rotation signal becomes zero. In FIG. 18, when PI control by a proportional compensator and an integral compensator is adopted in the deviation suppression compensator a3, the deviation signal is Se, and the PF shaft motor drive signal is Sd, the transfer function of the deviation suppression compensator is Can express.

Here, symbol kp is a proportional control gain, symbol Ti is an integration time constant, and symbol s is a Laplace operator. The values of kp and Ti, which are control parameters inside the PF axis deviation suppressing unit 1B3a, are changed based on the parameter D2 input from the outside.

Specifically, the parameter D2 manipulates the amplitude of the deviation signal Se by changing the proportional control gain kp, and the amplitude and phase of the deviation signal Se by changing the integration time constant Ti. In the sewing machine 100 according to the present embodiment, after the hook 132 releases the catch of the upper thread T, the intermediate presser 135 is lifted from the sewing object Ob during the period when the small hole 113a is lifted in accordance with the operation of the balance 133. In the period during which there is a possibility of contact with the upper thread T, the proportional control gain kp is decreased or the integration time constant Ti is changed longer based on the parameter D2.

Since the sewing machine 100 according to the fourth embodiment changes the proportional control gain kp to be small or the integration time constant Ti to be long based on the parameter D2, the external force of the intermediate presser motor 136 during the period when the upper thread T is in contact with the intermediate presser 135. Can slow down the response. By doing so, it is possible to reduce the frictional force generated between the upper thread T and the intermediate presser 135 when the upper thread T is pulled up with the intermediate presser 135 as a fulcrum. Therefore, the PF shaft deviation suppressing portion 1B3a of the sewing machine 100 according to the present embodiment prevents the upper thread T from being cut or unwound by the frictional force with the intermediate presser 135 when detecting the upper thread tension. The intermediate presser motor 136 can be driven.

Each function provided in the control panel of the sewing machine 100 according to the first to fourth embodiments can be realized using a processing circuit. The functions are the command generation unit 1A1 and the PF shaft motor control calculation unit 1A3. FIG. 19 is a diagram illustrating a first hardware configuration example of the control panel of the sewing machine according to the first to fourth embodiments. FIG. 20 is a diagram illustrating a second hardware configuration example of the control panel of the sewing machine according to the first to fourth embodiments. FIG. 19 shows an example in which the above processing circuit is realized by dedicated hardware such as the dedicated processing circuit 190. FIG. 20 shows an example in which the above processing circuit is realized by the processor 191 and the storage device 192.

As shown in FIG. 18, when using dedicated hardware, the dedicated processing circuit 190 includes a single circuit, a composite circuit, a programmed processor, a parallel programmed processor, an ASIC (Application Specific Integrated Circuit), and an FPGA (Field). Programmable Gate Array) or a combination thereof. Each of the above functions may be realized by a processing circuit, or may be realized by a processing circuit collectively.
As shown in FIG. 20, when the processor 191 and the storage device 192 are used, each of the above functions is realized by software, firmware, or a combination thereof. Software or firmware is described as a program and stored in the storage device 192. The processor 191 reads and executes the program stored in the storage device 192. It can also be said that these programs cause a computer to execute the procedures and methods executed by each of the above functions. The storage device 192 includes a RAM (Random Access Memory), a ROM (Read Only Memory), a flash memory, an EPROM (registered trademark) (Erasable Programmable Read Only Memory), or an EEPROM (Electrically Available Memory). To do. The semiconductor memory may be a nonvolatile memory or a volatile memory. In addition to the semiconductor memory, the storage device 192 may be a magnetic disk, a flexible disk, an optical disk, a compact disk, a mini disk, or a DVD (Digital
Versatile Disc).

In the configuration shown in the above-described embodiment, the load applied to the intermediate presser 135 from the upper thread is detected based on the PF shaft motor drive signal, but the present invention is not limited to this and is applied to the intermediate presser 135. A detection element for detecting a load may be provided in the intermediate press drive mechanism 151.

The configuration described in the above embodiment shows an example of the contents of the present invention, and can be combined with another known technique, and can be combined with other configurations without departing from the gist of the present invention. It is also possible to omit or change the part.

100 sewing machine, 101 arm, 102 spindle motor case, 103 sewing machine head, 104 bed, 105 support leg, 106 sliding plate, 111 XY stage, 112 holding device, 112a feed plate, 112b outer presser, 112c presser base, 112d air cylinder , 113 X-axis motor, 114 Y-axis motor, 115 X-axis drive mechanism, 115a moving race, 116 Y-axis drive mechanism, 116a Y-axis guide, 117, 118, 137, 150 Rotation information detector, 121 operation panel, 121a display 121b, 191 processor, 121c, 192 storage device, D1 sewing pattern data, 121d input device, 122, 122A control panel, 123 foot switch, 1A1 command generation unit, 1A2 spindle motor control calculation unit, 1A3 PF axis motor control calculation unit 1A4 X-axis mode Control unit, 1A5 Y-axis motor control calculation unit, 131, 131 ′ sewing needle, 131a, 131a ′ needle hole, 132 hook, 133 balance, 133a, 131a ′ small hole, 134 spindle motor, 135, 135 ′ intermediate presser , 135a, 135a ′ through hole, 136 intermediate presser motor, 138 coupling, 139 upper shaft, 140 balance driving mechanism, 141 needle bar driving mechanism, 142 needle bar, 143 bobbin case, 144 upper shaft pulley, 145 timing belt, 146 Lower shaft pulley, 147 large-diameter gear, 148 small-diameter gear, 149 lower shaft, 151 intermediate presser drive mechanism, 152 pinion, 153 rack, 154 slide guide, 155 slider, 156 intermediate presser bar holder, 157 intermediate presser bar, 158 thread winding stand 159 Spool, 160, 161, 164, 165, 16 The upper thread guide, 162
Pre-tension, 163 main tension, 190 dedicated processing circuit, a1 switch, a2 differentiator, a3 deviation suppression compensator, c1 filter processing unit, c2 recording unit, c3 comparator, T, T ′ upper thread, Td, Td ′ lower Thread, Ob, Ob 'Sewing product.

Claims (11)

To catch the upper thread inserted into the needle hole of the sewing needle and to entangle the upper thread and the lower thread,
A balance having a small hole through which the upper thread is inserted, and the small hole is lifted from a bottom dead center to a top dead center to pull up the upper thread from the sewing object to be sewn;
An intermediate presser for preventing the sewing product from being lifted;
A drive source for driving the intermediate presser;
Conveying means for conveying the sewing product;
A tension monitoring unit that monitors the upper thread tension based on a load applied to the intermediate presser by the upper thread when the upper thread comes into contact with the intermediate presser when the transport means transports the sewing product; ,
A sewing machine comprising: The sewing machine according to claim 1, wherein the tension monitoring unit detects the upper thread tension based on a load applied to the drive source.   The sewing machine according to claim 1 or 2, wherein the tension monitoring unit monitors the upper thread tension during a period from when the hook releases the upper thread until the small hole reaches a top dead center.   The sewing machine according to any one of claims 1 to 3, wherein the tension monitoring unit outputs a sewing failure signal that notifies a sewing failure when the upper thread tension is larger or smaller than a reference value input from outside. The tension monitoring unit includes a recording unit that records the needle thread tension for each needle,
The sewing machine according to any one of claims 1 to 3, wherein a sewing failure signal for notifying a sewing failure is output when a variation in the needle thread tension for each stitch is larger or smaller than a reference value input from outside. The tension monitoring unit includes a recording unit that records the needle thread tension for each needle,
4. A sewing failure signal for notifying a sewing failure is output when a difference between an upper thread tension recorded by the recording unit and an upper thread tension 35 monitored by the tension monitoring unit is larger than a set threshold value. The sewing machine according to any one of the above.   A command for generating a drive command for the drive source to stop the intermediate presser at a certain height with respect to the sewing product during a period in which the small hole ascends after the catch of the upper thread is released. The sewing machine according to any one of claims 1 to 6, further comprising a generator. A deviation suppression unit that controls the drive source so that a deviation signal obtained by a difference between a drive state of the drive source and the drive command becomes 0;
Proportional calculation for manipulating the amplitude of the deviation signal based on a parameter set from the outside of the deviation suppression unit during the period when the small hole is raised by the operation of the balance after the hook releases the upper thread. The sewing machine according to claim 7, wherein the gain of the machine is reduced. A deviation suppression unit that controls the drive source so that a deviation signal obtained by a difference between a drive state of the drive source and the drive command becomes 0;
The amplitude and phase of the deviation signal are manipulated based on parameters set from the outside of the deviation suppressing unit during the period when the small hole ascends as the balance operates after the hook releases the upper thread. The sewing machine according to claim 7, wherein the integration time constant of the integration computing unit is increased. Wherein detects the tension monitoring unit based on the needle thread tension monitoring sewing defects, the in pressing, or stop said sewing needle, said the bite, and the balance, it said in the pressing, and said conveying means The sewing machine according to any one of claims 1 to 9, wherein:   The sewing machine according to any one of claims 1 to 10, further comprising an indicator that detects a sewing failure based on an upper thread tension monitored by the tension monitoring unit and displays that a sewing failure has occurred.

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