JP2017176774A - sewing machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sewing machine capable of reducing secondary or higher-order vibrations among vibrations caused by the rotation of a motor.SOLUTION: In a sewing machine including an arm part, an arm shaft 7 that is installed inside the arm part and rotary-driven by a motor, and a needle bar that is supported by the arm part and vertically moved linked with the rotation of the arm shaft 7, a first balancer 47A is provided inside the arm part, having a balancer shaft 46 extending in parallel with the extension direction of the arm shaft 7, the balancer shaft 46 rotating in the reverse direction of the arm shaft 7 at a rotation speed of N times that of the arm shaft 7, wherein N represents an integer of 2 or more.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a sewing machine, and more particularly to a sewing machine that moves a needle bar up and down by rotation of a main shaft.

  A general sewing machine includes a pedestal that stands up from a work table including a bed, and an arm that extends in a horizontal direction from the upper end of the pedestal. Power is transmitted to the needle bar through the mechanism, and the needle bar moves up and down.

  The needle bar is disposed at the tip of the arm portion. Therefore, the power of the drive motor transmits the rotation of the upper shaft to the lower shaft of the bed portion via the belt drive in the pedestal, and the belt drive is transmitted to the shuttle mechanism via the lower shaft for rotation. The hook rotates.

  On the other hand, since the vertical movement of the needle bar becomes a cause of vibration, for example, a technique for reducing the balancer by rotating it in conjunction with the rotation of the upper shaft and the crank mechanism is known (for example, Patent Document 1). reference). The sewing machine disclosed in Patent Document 1 includes an upper shaft, a crank mechanism, and a balancer shaft. A gear is provided on each of the upper shaft and the balancer shaft and meshes with each other. The balancer shaft gear and the upper shaft gear have the same number of teeth. Therefore, the upper shaft, the crank mechanism, and the balancer shaft rotate in reverse at the same speed, and the sewing machine can reduce vibration.

Japanese Utility Model Publication No. 60-192774

  However, in the sewing machine disclosed in Patent Document 1, the balancer shaft gear and the upper shaft gear have the same diameter and the same number of teeth. Therefore, the balancer is configured to rotate at the same speed and reverse as the upper shaft and the crank mechanism. . That is, the primary vibration accompanying the rotation of the crank mechanism can be reduced. However, the sewing machine has vibration such as secondary vibration accompanying the vertical movement of the needle bar. Therefore, the sewing machine disclosed in Patent Document 1 has a problem in that vibrations after the secondary vibration cannot be reduced among a large number of primary, secondary, tertiary,...

  An object of the present invention is to provide a sewing machine that can reduce vibrations after secondary vibrations among vibrations generated by rotation of a motor.

  The sewing machine according to the first invention of the present application includes an arm portion, a main shaft provided inside the arm portion and driven to rotate by a motor, a needle bar supported by the arm portion and vertically moved in conjunction with the rotation of the main shaft. In the sewing machine comprising: a rotation shaft provided inside the arm portion and extending in parallel with the extending direction of the main shaft, the rotation shaft being N times the rotation speed of the main shaft (N is an integer of 2 or more) It has a first balancer that rotates at a speed in a direction opposite to the main shaft.

  The sewing machine of the first invention of the present application has a first balancer that rotates in the direction opposite to the main shaft. The first balancer rotates at N times the rotation speed of the main shaft (N is an integer of 2 or more). Therefore, the sewing machine can suppress the Nth order vibration among the vibrations generated with the rotation of the motor. By increasing the value of N, the sewing machine can suppress vibration in response to higher-order vibration. By appropriately selecting the value of N, the sewing machine can suppress the vibration to be suppressed most, corresponding to the difference in the natural frequency of the sewing machine itself.

  The sewing machine according to a second aspect of the present invention is the sewing machine according to the first aspect, further comprising a transmission mechanism provided between the main shaft and the first balancer for transmitting the rotation of the main shaft to the first balancer. .

  The sewing machine of the second invention of the present application has a transmission mechanism. The sewing machine can smoothly transmit the rotation of the main shaft to the first balancer.

  A sewing machine according to a third invention of the present application is the sewing machine according to the second invention, wherein the transmission mechanism includes a spindle pulley provided on the spindle, a balancer pulley provided on the first balancer, a spindle pulley and the balancer pulley. It has a double-toothed belt that spans between the inner teeth and meshes with the main shaft pulley and meshes with the balancer pulley with outer teeth.

  In the sewing machine of the third invention of the present application, the transmission mechanism transmits the rotation of the main shaft to the first balancer by the double tooth belt. Therefore, the sewing machine can be quieter during driving compared to, for example, using a gear for the transmission mechanism. Since the sewing machine does not require lubrication in the transmission mechanism, the sewing product can be prevented from being stained with the lubricant.

  A sewing machine according to a fourth invention of the present application is the sewing machine according to the third invention, wherein the sewing machine has a cylindrical support member that rotatably supports the rotary shaft and is provided in the arm portion, and the axis of the support member is the rotary shaft. The position of the balancer pulley provided on the rotating shaft can be changed by rotating the support member by decentering from the axis of the rotating shaft.

  In the sewing machine according to the fourth aspect of the present invention, the axis of the support member is eccentric from the axis of the rotating shaft. Therefore, the position of the balancer pulley is changed by rotating the support member while the arm portion supports the support member. By changing the position of the balancer pulley, the sewing machine can adjust the tension of both tooth belts.

  A sewing machine according to a fifth aspect of the present invention is the sewing machine according to any one of the first to fourth aspects, wherein the sewing machine includes a plurality of first balancers having different N values.

  The sewing machine of the fifth invention of the present application has a plurality of first balancers. The plurality of first balancers have different N values. The sewing machine can simultaneously suppress a plurality of vibrations corresponding to the value of N of each first balancer.

  ADVANTAGE OF THE INVENTION According to this invention, the vibration after the secondary vibration of the vibration which arises with rotation of a motor can be reduced.

It is a front view of the sewing machine which abbreviate | omitted one part. It is a top view of the sewing machine which fractured a part. It is a perspective view which shows the internal structure of a sewing machine. It is sectional drawing by the AA cross section in FIG. FIG. 5 is an enlarged explanatory view of a main part of FIG. 4. It is a perspective view of a balancer pulley, a supporting member, and the 1st balancer. It is sectional drawing by the BB cross section in FIG.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following description, the left side, right side, front side, back side, upper side, and lower side in FIG. 1 based on the direction of the reference sign are the rear, front, left, right side, upper side, and lower side of the sewing machine 1, respectively. .

  As shown in FIG. 1, the sewing machine 1 includes a bed portion 2, a pedestal portion 3, and an arm portion 4. The bed 2 is a box that extends in the front-rear direction. The pedestal 3 rises upward from the rear end of the bed 2. The arm part 4 extends in the horizontal direction forward from the upper end of the pedestal part 3. The sewing machine 1 transmits the rotational force of the drive motor 9 provided inside the pedestal 3 to the needle bar 6 through the upper shaft 7 so as to move up and down.

  Note that a hook mechanism 51, a thread trimming mechanism (not shown), and the like are provided inside the bed portion 2. However, since various mechanisms related to the sewing are well-known, a detailed description is given here. Description is omitted. Note that the shuttle mechanism 51 and the thread trimming mechanism are disposed on the front end side of the lower shaft 5 and are driven by transmitting the power of the rotation of the lower shaft 5 that rotates by receiving the drive of the drive motor 9. The lower shaft 5 extends horizontally in the front-rear direction inside the bed portion 2.

  As shown in FIG. 3, a lower power transmission mechanism 10 that transmits the rotational force of the drive motor 9 to the lower shaft 5 is provided at the rear end of the lower shaft 5. The lower power transmission mechanism 10 includes a lower shaft pulley 12 and transmission pulleys 13 and 14. The lower shaft pulley 12 is provided in the bed portion 2 at the rear end portion of the lower shaft 5. The transmission pulley 13 is provided on the lower left side of the lower shaft pulley 12 and is rotatably supported by the bed portion 2. The transmission pulley 14 is provided on the side opposite to the transmission pulley 13 with respect to the lower shaft pulley 12, and is supported by the bed portion 2 so as to be rotatable. A driving belt 11 as a timing belt is bridged between the lower shaft pulley 12 and the transmission pulleys 13 and 14. The drive belt 11 is a double-tooth belt, the inner teeth are hung on the transmission pulleys 13 and 14, and the outer teeth are hung on the lower shaft pulley 12.

  As shown in FIGS. 2 and 3, the drive belt 11 faces upward in the pedestal portion 3 and is coupled to the transmission mechanism 20 above the drive belt 11. The transmission mechanism 20 has an upper shaft pulley 21. The upper shaft pulley 21 is provided at the rear end portion of the upper shaft 7 in the vicinity of the upper end of the pillar portion 3. The drive belt 11 has an inner tooth hung on the upper shaft pulley 21. The output shaft of the drive motor 9 is connected to the rear of the upper shaft pulley 21 via a joint. Therefore, when the drive motor 9 is driven, the upper shaft pulley 21 rotates. As the upper shaft pulley 21 rotates, the upper shaft 7 rotates and the drive belt 11 travels. When the drive belt 11 travels, the lower shaft 5 rotates through the lower shaft pulley 12 and the transmission pulleys 13 and 14 of the lower power transmission mechanism 10, and the shuttle mechanism 51 is driven. The diameter of the lower shaft pulley 12 is half the diameter of the upper shaft pulley 21. Therefore, the lower shaft pulley 12 rotates at a double speed in the opposite direction to the upper shaft pulley 21.

  As shown in FIGS. 1 and 3, the upper shaft 7 extends horizontally in the front-rear direction inside the arm portion 4. The front end portion of the upper shaft 7 has a conversion mechanism 30 that converts the rotational movement of the upper shaft 7 into the vertical movement of the needle bar 6. The conversion mechanism 30 includes a needle bar crank 47B, a crank rod 31 and the like. The needle bar crank 47 </ b> B has a substantially fan shape when viewed from the front, has a thickness in the front-rear direction, and is provided at the front end portion of the upper shaft 7. The crank rod 31 extends in the vertical direction, and the upper end of the crank rod 31 is rotatably connected to a position eccentric from the fixed position of the upper shaft 7 in the needle bar crank 47B. The lower end of the crank rod 31 is connected to the needle bar 6.

  The needle bar 6 extends in the vertical direction and is supported by a cylindrical guide 8 provided at the lower end of the front end of the arm portion 4 so as to be movable up and down. A sewing needle 61 is detachably attached to the lower end of the needle bar 6.

  However, since the conversion mechanism 30 converts the rotational movement of the upper shaft 7 into the vertical movement of the needle bar 6 by the needle bar crank 47B, the crank rod 31 and the like, secondary vibration is caused by the vertical movement of the needle bar 6. Occur.

  Therefore, as shown in FIG. 4, on the rear side of the upper shaft 7 than the conversion mechanism 30 (on the side opposite to the tip side of the arm portion 4), a vibration absorbing unit 40 for suppressing this multidimensional vibration. Is arranged.

  As shown in FIGS. 4 to 6, the vibration absorbing unit 40 includes a driving pulley 41, a support shaft 42, a driven pulley 43, an endless double-tooth belt 44, a balancer pulley 45, and a balancer shaft 46. And a substantially fan-shaped first balancer 47A. The driving pulley 41 is provided coaxially with the upper shaft 7 behind the needle bar crank 47B. The support shaft 42 extends in the front-rear direction at the left rear of the upper shaft 7 and is supported by the arm portion 4. The driven pulley 43 is rotatably provided on the support shaft 42. The front-rear direction positions of the driving pulley 41 and the driven pulley 43 are the same. The both tooth belts 44 span the inner teeth on the inner peripheral surface side between the upper shaft pulley 41 and the driven pulley 43. The balancer pulley 45 is between the upper shaft pulley 41 and the driven pulley 43 and meshes with external teeth on the outer peripheral surface side of the both tooth belts 44. The balancer pulley 45, the driving pulley 41, and the driven pulley 43 have the same position in the front-rear direction. The balancer shaft 46 extends in the front-rear direction at the upper left of the upper shaft 7 and fixes the rear end balancer pulley 45. The first balancer 47A is substantially fan-shaped when viewed from the front and fixed to the front end of the balancer shaft 46, and has a thickness in the front-rear direction.

  As shown in FIGS. 6 and 7, the balancer shaft 46 includes a support member 46A between the balancer pulley 45 and the first balancer 47A. The support member 46A has a substantially cylindrical shape extending in the front-rear direction, and has a flange portion 46B protruding in the radial direction at the front end portion. The flange portion 46B has a groove portion 46C that is recessed in the axial direction of the support member 46A on the front side surface. The support member 46 </ b> A is supported by the arm unit 4. The support member 46A has a through hole 46D penetrating in the front-rear direction. A pair of bearings 46E are fitted to both front and rear ends of the through hole 46D, and the bearings 46E support the balancer shaft 46 in a rotatable manner. That is, the support member 46A supports the balancer shaft 46 in the arm portion 4 so as to be rotatable.

  As shown by a two-dot chain line in FIG. 7, the axis of the support member 46 </ b> A is eccentric from the axis of the balancer shaft 46. Therefore, the position of the balancer pulley 45 changes when an operator inserts a tool into the groove 46C from the front and rotates the support member 46A while the arm portion 4 supports the support member 46A. By changing the position of the balancer pulley 45, the sewing machine 1 can adjust the tension of the two tooth belts 44.

  As shown in FIG. 5, the diameter of the balancer pulley 45 is n, and the diameter of the driving pulley 41 is 2n. The balancer pulley 45 meshes with the external teeth of the two-tooth belt 44, and the driving pulley 41 meshes with the internal teeth of the both-tooth belt 44. That is, the balancer pulley 45 rotates at a speed twice that of the driving pulley 41 and rotates in the opposite direction to the driving pulley 41. Therefore, the first balancer 47 </ b> A rotates at a speed twice that of the upper shaft 7 and rotates in the opposite direction to the driving pulley 41. That is, the vibration absorbing unit 40 transmits the rotation of the upper shaft 7 to the first balancer 47A.

  As described above, the sewing machine 1 includes the arm portion 4, the upper shaft 7 provided inside the arm portion 4 and driven to rotate by the drive motor, and supported by the arm portion 4. A needle bar 6 that moves. The arm portion 4 has a balancer shaft 46 extending in parallel with the extending direction of the upper shaft 7, and the balancer shaft 46 is N times the rotational speed of the upper shaft 7 (N is an integer of 2 or more). Thus, the first balancer 47A that rotates in the direction opposite to the upper shaft 7 is provided.

  The balancer shaft 46 fixes the first balancer 47A so that it cannot rotate relative to the rotation direction of the upper shaft 7 in the opposite direction. The first balancer 47A rotates at N times the rotation speed of the upper shaft 7 (N is an integer of 2 or more). Therefore, the sewing machine 1 can suppress Nth-order vibration among vibrations generated with the rotation of the drive motor. By increasing the value of N, the sewing machine 1 can suppress vibration in response to higher-order vibration. By appropriately selecting the value of N, the sewing machine 1 can suppress the vibration to be suppressed most, corresponding to the difference in its own natural frequency.

  In addition, the vibration absorption unit 40 comprises the transmission mechanism of a claim. This transmission mechanism smoothly transmits the rotation of the upper shaft 7 to the first balancer 47A. The transmission mechanism spans between a drive pulley 41 provided on the upper shaft 7, a balancer pulley 45 provided on the first balancer 47A, and the drive pulley 41 and the balancer pulley 45. And a double-tooth belt 44 with external teeth meshing with the balancer pulley 45.

  In the sewing machine 1, the transmission mechanism transmits the rotation of the upper shaft 7 to the first balancer 47 </ b> A by the double-tooth belt 44. Therefore, the sewing machine 1 can be calmed during driving as compared to, for example, using a gear for the transmission mechanism. Since the sewing machine 1 does not require lubrication in the transmission mechanism, the sewing product can be prevented from being stained with the lubricant.

  In the above description, the upper shaft 7 corresponds to the “main shaft” of the present invention. The balancer shaft 46 corresponds to the “rotating shaft” of the present invention. The driving pulley 41 corresponds to the “spindle pulley” of the present invention.

  The present invention is not limited to the above embodiment and can be variously modified. In the sewing machine 1, the first balancer 47 </ b> A rotates at a speed twice that of the upper shaft 7 and rotates in the direction opposite to the driving pulley 41, but is not limited thereto. The sewing machine 1 may include a plurality of first balancers 47A having different N values at the rotational speeds of the balancer shaft 46 and the upper shaft 7. For example, a plurality of first balancers 47A with N = 2, 3, 4 may be provided, and the rotation of the upper shaft 7 may be transmitted by the respective transmission mechanisms. The sewing machine 1 can simultaneously suppress a plurality of vibrations corresponding to the value of N of each first balancer 47A.

  The axis of the support member 46A may coincide with the axis of the balancer shaft 46. In this case, the sewing machine 1 may be separately provided with an idler pulley for adjusting the tension of the both tooth belts 44.

  The vibration absorbing unit 40 of the above embodiment can be applied to a gear meshing configuration instead of the balancer pulley 45 and the driving pulley 41. In this case, by setting the gear ratio of the gear instead of the balancer pulley 45 and the gear instead of the driving pulley 41 to 1: 2, the first balancer 47A becomes a double speed and reverse rotation of the main shaft, and the secondary vibration. Can be reduced.

  The driving pulley 41, the balancer pulley 45, and the both tooth belts 44 may not be provided. In this case, a motor that directly rotates the balancer shaft 46 may be provided separately. The sewing machine 1 only needs to drive the motor and the drive motor 9 synchronously and rotate the first balancer 47A in the direction opposite to the upper shaft 7.

  In the above description, “vertical” and “horizontal” are not strictly vertical / horizontal. That is, the terms “vertical” and “horizontal” mean “substantially vertical” and “substantially horizontal”, allowing design and manufacturing tolerances and errors in addition to the installation environment of the sewing machine 1.

1 Sewing machine 4 Arm 6 Needle bar 7 Upper shaft (main shaft)
40 Vibration absorption unit 41 Drive pulley (spindle pulley)
44 Double-tooth belt 45 Balancer pulley 46 Balancer shaft (rotating shaft)
46A Support member 47A First balancer 47B Needle bar crank

Claims (5)

An arm,
A main shaft provided inside the arm portion and driven to rotate by a motor;
In a sewing machine that is supported by the arm portion and includes a needle bar that moves up and down in conjunction with rotation of the main shaft,
A rotation shaft provided inside the arm portion and extending in parallel with an extending direction of the main shaft, wherein the rotation shaft is N times the rotation speed of the main shaft (N is an integer of 2 or more); A sewing machine having a first balancer that rotates in a direction opposite to that of the first balancer. The sewing machine according to claim 1, further comprising a transmission mechanism that is provided between the main shaft and the first balancer and transmits the rotation of the main shaft to the first balancer. The transmission mechanism is
A spindle pulley provided on the spindle;
A balancer pulley provided on the rotating shaft of the first balancer;
3. The belt according to claim 2, further comprising: a double-tooth belt that spans between the main shaft pulley and the balancer pulley, the inner teeth mesh with the main shaft pulley, and the outer teeth mesh with the balancer pulley. sewing machine. A cylindrical support member that rotatably supports the rotating shaft and is provided in the arm portion,
The axis of the support member is eccentric from the axis of the rotary shaft;
The sewing machine according to claim 3, wherein the position of the balancer pulley provided on the rotation shaft can be changed by rotating the support member. 5. The sewing machine according to claim 1, comprising a plurality of the first balancers having different values of N from each other. 6.

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