JP5196233B2 - Sewing needle swing mechanism of sewing machine - Google Patents

Description

  The present invention relates to a needle bar swinging mechanism of a sewing machine having a zigzag stitching (staggered stitching) function.

  One of the functions of the sewing machine is so-called zigzag stitching (staggered stitching) in which the needle bar is slid to the left and right in the sewing direction of the cloth. Conventionally, a bar-shaped link is rocked by an actuator, and the movement is mechanically transmitted, whereby the needle bar is rocked left and right and sewn in a zigzag pattern. In the device disclosed in Patent Document 1, a stepping motor is used as an actuator, and repetitive rotational motion of a driven shaft (rotating shaft) of the stepping motor is converted into reciprocating linear motion by a transmission means using a screw. Then, this reciprocating linear motion is converted into a peristaltic motion by a link, and the needle bar is perforated. Patent Document 2 discloses an invention in which two actuators that act on a link that swings a needle bar are provided. An actuator with a large amount of swing and an actuator with a small amount of swing individually swing the link in the same direction, whereby the needle bar is swung at high speed and with high accuracy.

In order to perform zigzag sewing by swinging the needle bar, it is determined how accurately the needle held on the needle bar can be stabbed into the cloth to achieve a beautiful sewing. For this reason, it is important to swing the bar-shaped link where the connecting portion is easily rattled with high speed and accuracy and transmit it to the needle bar. In Patent Document 1, accuracy is realized by using a ball screw or a roller screw as a screw for transmitting the repetitive rotational motion of the stepping motor. In Patent Document 2, the needle bar is rocked at high speed and with high accuracy by being largely rocked by an actuator having a large amount of swing and finely adjusting by an actuator having a small amount of swing.
Japanese Utility Model Publication No. 7-33274 JP-A-10-61740

  However, since the ball screw or roller screw used in Patent Document 1 is a component that requires precise processing and assembly, the cost increases. In Patent Document 2, since two stepping motors are used as actuators, a space for arranging the two motors is required. In addition, a mechanism for driving the two motors in a coordinated manner is complicated, and thus costs are increased.

  The present invention has been made in view of the above problems, and provides a needle bar swinging mechanism for a sewing machine that does not have a complicated configuration and suppresses an increase in cost, and is capable of zigzag sewing with high speed and accuracy without rattling. This is a problem to be solved.

The structural features of the invention according to claim 1 for solving the above-described problems are a needle bar,
A needle bar arm that holds the needle bar up and down;
A link having one end held by the needle bar arm;
A motor connected to the other end of the link and swinging the needle bar in the left-right direction via the link;
An urging member that urges the needle bar arm and the link in one direction in the left-right direction in which the needle bar swings;
An auxiliary biasing member for biasing the needle bar arm and the link in the other direction against the biasing force by the biasing member;
I have a,
The motor has an external gear attached to a motor rotation shaft, and the link has a tentering rod whose one end is held by the needle bar arm, one end connected to the other end of the tentering rod, and the other end is the and to have a width out gear meshing with the gear of the motor.

  The needle bar swinging mechanism of the sewing machine according to the present invention presses back of a connecting part such as a link that transmits the rotational force of a motor for swinging the needle bar arm to the left and right for zigzag sewing or the like as the left and right movement of the needle bar. Therefore, it has a biasing member that biases the needle bar arm in one of the left and right directions. And it has the auxiliary | assistant urging member which applies urging | biasing force to the other which reverses in the left-right direction with respect to the urging member. With the urging member, the needle bar arm swings left and right, and when sewing patterns such as zigzags or straight stitches, it prevents looseness that may cause stitches that do not sew cleanly due to resistance caused by the needle sticking into the cloth. Removed. Then, the load is applied in a certain direction by the urging member, so that a large force is required when swinging in the opposite direction, and the auxiliary urging member of the urging member is suppressed so that the motor is not enlarged. The biasing force is applied in the opposite direction to the biasing force.

  According to the needle bar swinging mechanism of the sewing machine of the present invention, the backlash due to the mechanism that swings the needle bar arm to the left and right is suppressed by the urging member in linear stitching, zigzag sewing, etc., and zigzag sewing etc. can be performed at high speed and with high accuracy. . Moreover, since the capacity | capacitance of a motor can be made small by using the auxiliary | assistant biasing member biased in the reverse direction with respect to the biasing force of a biasing member, a motor can be reduced in size.

  The motor has an external gear attached to a motor rotation shaft, and the link has an extension rod whose one end is held by the needle bar arm, one end connected to the other end of the extension rod, and the other end And a tentering gear that meshes with the gear of the motor. By adopting such a configuration, the needle bar arm is swingable to the left and right as the rotational force of the motor is changed to the left and right movement, so that the mechanism is simple and easy to assemble.

  According to a second aspect of the present invention, the auxiliary biasing member is attached to the rotating shaft of the motor, and the needle bar arm and the link are biased by the biasing member. When the needle bar arm and the link are urged in the other direction, the needle bar arm and the link are biased in the other direction. By adopting such a configuration, when the needle bar arm swings in the direction in which the biasing member is biased, a reverse biasing force is not applied, so that the backlash caused by the needle bar arm and the link is surely suppressed. Can do. When the needle bar arm swings in the direction opposite to the direction in which the urging member urges, the urging force is applied by the auxiliary urging member in the direction opposite to the urging force of the urging member, so that the driving torque of the motor is increased. Therefore, the motor can be reduced in size and the cost can be reduced.

Further, the structural feature of the invention according to claim 3 is that, in claim 1 or 2 , the urging member and the needle bar arm in the direction opposite to the direction in which the motor is positioned in the left-right direction swinging the needle bar. It is a tension spring that urges the link. Since the tension spring is used as the urging member, it is not costly and has no play and can be zigzag stitched with high speed and accuracy.

  In the invention according to claim 1, in the straight stitch, zigzag stitch or the like, the backlash due to the mechanism for swinging the needle bar arm to the left or right is suppressed by the biasing member, and zigzag stitch or the like can be performed at high speed and with high accuracy. Moreover, since the capacity | capacitance of a motor can be made small by using the auxiliary | assistant biasing member biased in the reverse direction with respect to the biasing force of a biasing member, a motor can be reduced in size.

Then, the link consisting of the tentering rod and tentering gear and the external gear fixed to the rotating shaft of the motor change the rotational force of the motor to the left and right and swing the needle bar arm to the left and right. Since the bar arm is urged in one direction by the urging member, the play can be suppressed with a simple configuration.

  In the invention according to claim 2, since the reverse urging force is not applied when the needle bar arm swings in the urging direction of the urging member, the backlash caused by the needle bar arm and the link is reliably suppressed. Can do. When the needle bar arm swings in the direction opposite to the direction in which the urging member urges, the urging force is applied by the auxiliary urging member in the direction opposite to the urging force of the urging member, so that the driving torque of the motor is increased. Therefore, the motor can be reduced in size and the cost can be reduced.

In the invention according to claim 3 , since the tension spring is used as the urging member, the zigzag sewing or the like can be performed with high speed and high accuracy without cost and without rattling.

Hereinafter, embodiments will be described with reference to FIGS.
(Embodiment 1)
As shown in FIG. 1, a machine body 1 that is a main element of a sewing machine is covered with a housing 1 a and includes an arm machine frame 10 and a bed machine frame 11. The arm machine frame 10 and the bed machine frame 11 are not mainly cast, but are mainly formed of a sheet metal molded body obtained by press-molding a metal plate having a predetermined thickness. The arm machine frame 10 is provided with a needle bar 21 capable of holding the needle 20 so as to be able to move up and down, and an upper shaft 3 along the horizontal direction is rotatably provided. The upper shaft 3 is rotatably supported by a pair of bearings 31 fixed to the arm machine casing 10. A hand wheel 5 and a pulley 6 are fixed to one end of the upper shaft 3 (right side in FIG. 1). The pulley 6 includes a large-diameter driven pulley 61 and a first timing pulley 62. The drive belt 15 is hung on the motor pulley 121 and the driven pulley 61 fixed to the drive motor 12 fixed to the arm machine frame 10 below the pulley 6, and the rotation of the drive motor 12 is decelerated to the upper shaft 3. Communicated. A crank rod 32 is connected to the other end of the upper shaft 3, and the rotational motion of the upper shaft 3 is moved up and down (in the directions of arrows Y 1 and Y 2) through the crank rod 32.

  The lower shaft 4 is held inside the bed machine frame 11. The lower shaft 4 is rotatably supported by a bearing 41 and an eccentric bearing 42. The bearing 41 and the eccentric bearing 42 are held on the bed machine frame 11 at a predetermined distance from each other in the longitudinal direction of the lower shaft 4. The lower shaft 4 and the upper shaft 3 are each provided with a power transmission belt 13 at one end thereof.

  The needle bar 21 is held by the needle bar arm 22 so as to be slidable up and down, and the needle bar arm 22 is held by the arm machine frame 10 so as to be swingable right and left around the needle bar arm screw 23. As shown in FIGS. 1 and 2, a link 7 composed of a tentering rod 71 and a tentering gear 72 is connected to the lower side of the needle bar arm 22, and a stepping motor 8 serves as a drive source for the link 7. It is being fixed to the arm machine casing 10 via. The tenter rod 51 is a rod-shaped member. In FIGS. 1 and 2, the needle bar 21 and the needle bar arm 22 are located on the left side, and the stepping motor 8 is located on the right side. The tenter gear 72 includes an arcuate gear portion 721 and a connecting portion 722 that is coupled to the tenter rod 71 on the opposite side of the gear portion 721. A driven shaft (rotating shaft) 80 of the stepping motor 8 is fixed to a driven shaft 80 so as to rotate together with the driven shaft 80 as shown in FIG. Yes. The stepping motor 8 is rotated by computer control in accordance with information such as the rotation of the upper shaft 3 and the width swing amount and the type of yarn / cloth.

  Returning to FIGS. 1 and 2, a needle bar spring (biasing member) 24 is disposed between the needle arm bar 22 and the arm machine frame 10. The needle bar spring 24 is a torsion coil, one end is engaged with the side surface of the needle bar arm 22 and the other end is engaged with the arm machine frame 10, and the needle bar arm 22 and the link 7 are connected to the arm machine frame 10 side (arrow X1). Stretched in the direction).

  The gear 81 includes a gear portion (not shown) that meshes with the tentering gear 72 and a cylindrical portion (not shown) that serves as a core of an auxiliary spring (auxiliary biasing member) 9 described later. The cylindrical portion is provided with a notch (not shown), and one end of the auxiliary spring 9 is fixed to receive the torque of the auxiliary spring 9. The other end 91 of the auxiliary spring 9 is engaged with a convex portion 141 provided on the bracket 14 for fixing the stepping motor 8 to the arm machine frame 10. The auxiliary spring 9 is held by a push nut 92 so as not to be detached from the cylindrical portion of the gear 81. The auxiliary spring 9 biases the rotation of the stepping motor 8 when the needle bar spring 24 swings in the direction opposite to the direction in which the needle bar spring 24 biases.

  When zigzag sewing is performed with the sewing machine according to the first embodiment, the stepping motor 8 is rotated in accordance with the rotation of the upper shaft 3 by computer (not shown) control and rotates in the same manner as the driven shaft 80 of the stepping motor 8. The gear 81 rotates and the tentering gear 72 rotates. In FIG. 2, the tentering gear 72 has a gear portion 721 that moves up and down (in the directions of arrows A1 and A2), and a tentering rod 71 that is connected to the connecting portion 721 and the connecting portion 721 in the left and right directions (in the directions of arrows B1 and B2). Move. Then, the left and right movement of the tentering rod 71 swings the needle bar arm 22 left and right. Further, the lower shaft 4 on the bed machine frame 11 side also rotates in conjunction with the rotation of the upper shaft 3, and the cloth is fed in cooperation with the cloth feeding mechanism located below the needle bar arm 22. The needle 20 is swung left and right by the left and right swinging of 22, and is sewn in a zigzag pattern. Here, since the amount of sewing width depends on the amount of movement of the needle bar arm 22, if the rotation amount of the stepping motor 8 is not accurately transmitted to the needle bar arm 22, unevenness will occur in the stitch width after sewing. . Or, even in straight-line stitching, if there is play between the links 7 due to resistance when the needle sticks into the cloth, the needle bar arm 22 will swing left and right by that amount, so that it will not sew on a clean straight line. There is. Therefore, by pulling the needle bar arm 22 and the link 7 in one direction by the needle bar spring 24, the play between the link 7 and the play between the link 7 and the needle bar arm 22 can be eliminated.

  The needle bar spring 24 always pulls the needle bar arm 22 in one direction, leftward in FIGS. 1 and 2. The tensile load is minimized when the needle bar spring 24 is most contracted, that is, when the needle 20 is stuck in the cloth at the leftmost position (when the left needle is dropped), and the most extended state, that is, when the needle 20 is one. Maximum when stabbed into cloth in rightmost position (when right needle falls). Therefore, the minimum driving torque of the stepping motor 8 is a specification having a torque that can be applied to the maximum load of the needle bar spring 24 when the right needle is dropped.

  The auxiliary spring 9 is biased in the direction opposite to the biasing force of the needle bar spring 24. That is, in FIG. 3, when the tentering gear 72 swings in the A2 direction and the connecting portion 722 swings in the C1 direction, the driving torque of the stepping motor 8 in the C1 direction is urged to decrease. FIG. 3C is a view of the vicinity of the stepping motor 8 in FIG. 2 as viewed from the rear. Therefore, the C1 direction is the same direction as the B1 direction.

  According to the first embodiment, the needle bar spring 24 removes the play generated at the connecting portion between the needle bar arm 22 and the link 7, the link widening rod 71 and the widening gear 72, and the gear portion 721 and the gear 81 of the widening gear 72. Therefore, even if the stepping motor 8 is rotated at a high speed, it is possible to sew a zigzag stitch or the like with high accuracy. Then, by attaching the auxiliary spring 9 to the driven shaft 80 of the stepping motor 8, when the needle bar arm 22 is bent in the opposite side (B1 direction) of the urging direction (B2 direction) urged by the needle bar spring 24, Since the urging force of the needle bar spring 24 can be weakened or eliminated by the urging force of the auxiliary spring 9, the driving torque of the stepping motor 8 can be reduced. That is, since the driving torque for the state in which the needle bar spring 24 is extended most is required as the minimum driving torque of the stepping motor 8, it can be reduced, and the stepping motor 8 can be downsized.

The structure of the link 7, the structure of the backlash removal by the needle bar spring 24, and the structure of the motor downsizing by the auxiliary spring 9 do not require complicated mounting that requires precision, so it is simple and accurate without cost. A sewing machine can be provided.
(Embodiment 2)
The sewing machine according to the second embodiment is substantially the same as the sewing machine according to the first embodiment, except that the needle bar arm 22 and the needle bar spring 24 are different, and has the same operational effects as the first embodiment. Therefore, detailed description of the same configuration as that of the first embodiment is omitted.

  In the sewing machine according to the second embodiment, as shown in FIG. 4, the needle bar arm 22 is urged in one direction in the left-right direction by a needle bar urging member (urging member) 25. The needle bar arm 22 has an engagement portion 221 formed on the side surface (the left side surface in the drawing). The needle bar urging member 25 includes a pressing member 251 and a torsion spring 252. The pressing member 251 contacts the engaging portion 221 of the needle bar arm 22 and presses the needle bar arm 22 so as to urge the needle bar arm 22 in one direction, and a locking portion 254 where one end of the torsion spring 252 locks. And a rotation center portion 250 is formed to be rotatably attached to the arm machine casing 10. The other end of the torsion spring 252 is locked to the arm machine frame 10.

  In FIG. 4, the torsion spring 252 pulls the locking portion 254 upward so that the pressing member 251 rotates about the rotation center portion 250 and the contact portion 253 moves the engagement portion 221 to the left. To push, the needle bar arm 22 is urged to the left.

  According to the second embodiment, the needle bar urging member 252 eliminates backlash at the connecting portion between the needle bar arm 22 and the link 7, the widening rod 71 and the widening gear 72, and the widening gear 72 and the gear 81. it can.

  The preferred embodiment of the present invention has been described above, but the present invention is not limited to the above embodiment. For example, the needle bar spring 24 and the needle bar urging member 25 only need to urge the needle bar arm 21 in one direction in the left-right direction. Further, the link 7 constituted by the tentering rod 71 and the tentering gear 72 may use a member other than the tentering rod 71 and the tentering gear 72, or may function as a link mechanism using members having different shapes.

  The present invention can be applied to household sewing machines, commercial sewing machines, and the like.

1 is a configuration diagram of a sewing machine according to Embodiment 1. FIG. It is a block diagram of the needle bar rocking mechanism of the sewing machine according to the first embodiment. It is a figure which shows the principal part of the needle bar rocking | fluctuation mechanism of the sewing machine which concerns on this Embodiment 1. FIG. It is a block diagram of the needle bar rocking mechanism of the sewing machine according to the second embodiment.

1: Airframe, 1a: Housing, 10: Arm machine frame, 11: Bed machine frame, 13: Power transmission belt, 14: Bracket,
20: Needle, 21: Needle bar, 22: Needle bar arm, 23: Needle bar arm screw, 24: Needle bar spring, 25: Needle bar biasing member,
3: upper shaft, 31: bearing, 32: crank rod 4: lower shaft, 41: bearing, 42: eccentric bearing,
5: Handwheel
6: pulley,
7: Link, 71: Widening rod, 72: Widening gear,
8: Stepping motor, 80: Driven shaft, 81: Gear
9: auxiliary spring, 91: other end, 92: push nut.

Claims (3)

A needle bar,
A needle bar arm that holds the needle bar up and down;
A link having one end held by the needle bar arm;
A motor connected to the other end of the link and swinging the needle bar in the left-right direction via the link;
An urging member that urges the needle bar arm and the link in one direction in the left-right direction in which the needle bar swings;
An auxiliary biasing member for biasing the needle bar arm and the link in the other direction against the biasing force by the biasing member;
I have a,
The motor has an external gear attached to a motor rotation shaft, and the link has a tentering rod whose one end is held by the needle bar arm, one end connected to the other end of the tentering rod, and the other end is the needle bar swinging mechanism of the sewing machine, characterized by chromatic and tentering gear meshed with the gear of the motor.   2. The auxiliary biasing member according to claim 1, wherein the auxiliary biasing member is attached to a rotation shaft of the motor, and the needle bar arm and the link are swung in another direction against a biasing force by the biasing member. A needle bar swinging mechanism for a sewing machine, wherein the bar arm and the link are biased in the other direction. 3. The urging member according to claim 1, wherein the urging member is a tension spring that urges the needle bar arm and the link in a direction opposite to a direction in which the motor is positioned in a lateral direction in which the needle bar is swung. The needle bar swing mechanism of the sewing machine.

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