Sewing machine with

Abstract

To adjust the shape of a seam.SOLUTION: A frame including a bed portion having an upper surface, a cylinder portion protruding from the bed portion to one side in a first direction of a predetermined plane parallel to the upper surface and having a smaller dimension than the bed portion in a second direction orthogonal to the first direction on the predetermined plane, a body portion extending upward from the bed portion in a third direction orthogonal to the predetermined plane, an arm portion extending from an upper end portion of the body portion to the one side in the first direction, and a head portion protruding downward from the arm portion; The sewing machine includes a needle bar that reciprocates in the third direction while holding a sewing machine needle that holds an upper thread, a pressing member that presses a sewing object disposed at a sewing position directly below the sewing machine needle, an annular first lower feed belt that is disposed on one side of the sewing position in the first direction and moves so as to feed the sewing object in the second direction, and an annular second lower feed belt that is disposed on the other side of the sewing position and moves so as to feed the sewing object in the second direction independently of the first lower feed belt. The first lower feed belt and the second lower feed belt are disposed in the internal space of the cylinder portion.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The technology disclosed in this specification relates to a sewing machine. [Background technology]

[0002] BACKGROUND ART In the technical field of sewing machines, a cylinder head sewing machine such as that disclosed in Patent Document 1 is known. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-057758 Summary of the Invention [Problem to be solved by the invention]

[0004] Sewing machines produce sewn products by forming stitches while feeding the sewing object in a predetermined feed direction. For example, there is a demand for technology that allows the shape of the stitches to be adjusted as desired to improve the design of the sewn product.

[0005] The technology disclosed in this specification aims to adjust the shape of a stitch. [Means for solving the problem]

[0006] This specification discloses a sewing machine. The sewing machine includes a frame having a bed section with an upper surface, a cylinder section that protrudes from the bed section to one side in a first direction on a predetermined plane parallel to the upper surface and has a dimension smaller than that of the bed section in a second direction perpendicular to the first direction on the predetermined plane, a body section that extends upward from the bed section in a third direction perpendicular to the predetermined plane, an arm section that extends from the upper end of the body section to one side in the first direction, and a head section that protrudes downward from the arm section, a needle bar that is movably supported on the head section and moves back and forth in the third direction while holding a sewing needle that holds an upper thread, a presser member that presses down a sewing object that is located at a sewing position directly below the sewing needle, a first annular lower feed belt that is located on one side of the sewing position in the first direction and moves to feed the sewing object in a second direction, and a second annular lower feed belt that is located on the other side of the sewing position and moves to feed the sewing object in the second direction independently of the first lower feed belt. The first and second lower feed belts are located in the internal space of the cylinder section. [Effects of the Invention]

[0007] According to the present disclosure, the shape of the stitches can be adjusted. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view of a sewing machine according to a first embodiment, seen from the upper left rear side. [Figure 2] FIG. 2 is a partially cutaway left side view showing the sewing machine according to the first embodiment. [Figure 3] FIG. 3 is a perspective view showing the internal space of the cylinder portion according to the first embodiment, as viewed from the upper left rear side. [Figure 4] FIG. 4 is a perspective view showing a part of the lower feed mechanism according to the first embodiment, seen from the upper left rear side. [Figure 5] FIG. 5 is a bottom view showing the bottom feed mechanism according to the first embodiment. [Figure 6] FIG. 6 is a left side view showing the lower feed mechanism according to the first embodiment. [Figure 7]FIG. 7 is a perspective view showing the lower feed mechanism according to the first embodiment, seen from the upper left rear side. [Figure 8] FIG. 8 is a block diagram showing a controller of the sewing machine according to the embodiment. [Figure 9] FIG. 9 is a diagram for explaining stitches formed on a sewing object according to the embodiment. [Figure 10] FIG. 10 is a bottom view showing the bottom feed mechanism according to the second embodiment. [Figure 11] FIG. 11 is a perspective view showing the lower feed mechanism according to the second embodiment, seen from the upper left rear side. [Figure 12] FIG. 12 is a bottom view showing the bottom feed mechanism according to the third embodiment. [Figure 13] FIG. 13 is a left side view showing the lower feed mechanism according to the third embodiment. [Figure 14] FIG. 14 is a perspective view showing the lower feed mechanism according to the third embodiment, seen from the upper left rear side. [Figure 15] FIG. 15 is a rear view showing a part of the lower feed mechanism according to the embodiment. [Figure 16] FIG. 16 is a cross-sectional view showing a part of the lower feed mechanism according to the embodiment. [Figure 17] FIG. 17 is a bottom view showing a bottom feed mechanism according to a modified example. [Figure 18] FIG. 18 is a bottom view showing a bottom feed mechanism according to a modified example. [Figure 19] FIG. 19 is a bottom view showing a bottom feed mechanism according to a modified example. [Figure 20] FIG. 20 is a bottom view showing a bottom feed mechanism according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments will be described with reference to the drawings. The components of each embodiment described below can be combined as appropriate. In addition, some components may not be used.

[0010] In the embodiment, the positional relationship of each part is described using the terms "left," "right," "front," "rear," "up," and "down." These terms indicate relative positions or directions based on the center of the sewing machine 1. The left-right direction is a first direction parallel to the left-right axis of a local coordinate system defined for the sewing machine 1. The front-rear direction is a second direction parallel to the front-rear axis of the local coordinate system defined for the sewing machine 1. The up-down direction is a third direction parallel to the up-down axis of the local coordinate system defined for the sewing machine 1. The left-right axis (first direction), the front-rear axis (second direction), and the up-down axis (third direction) are mutually orthogonal. One side of the first direction is the left side, and the other side of the first direction is the right side. One side of the second direction is the front side, and the other side of the second direction is the rear side. One side of the third direction is the upper side, and the other side of the third direction is the lower side. The third direction is orthogonal to a predetermined plane including the left-right axis (first direction) and the front-rear axis (second direction). In the embodiment, the predetermined surface is parallel to the horizontal surface. However, the predetermined surface may be inclined relative to the horizontal surface.

[0011] [First embodiment] A first embodiment will be described.

[0012] <Sewing machine overview> Fig. 1 is a perspective view from the upper left rear side showing a sewing machine 1 according to an embodiment. Fig. 2 is a left side view, with a part cut away, showing the sewing machine 1 according to an embodiment. In the embodiment, the sewing machine 1 is a cylinder head sewing machine.

[0013] As shown in Figures 1 and 2, the sewing machine 1 includes a frame 2, a needle bar 4, a thread take-up lever 5, a thread tensioner 6, a needle plate 7, a presser foot 8, a shuttle 9, a sewing machine motor 12, an upper feed mechanism 10, and a lower feed mechanism 11A.

[0014] The frame 2 is a structure that supports the needle bar 4, the thread take-up lever 5, the thread tension controller 6, the needle plate 7, the presser foot, the shuttle 9, the upper feed mechanism 10, and the lower feed mechanism 11A. The frame 2 has a bed 20, a cylinder 21, a body 22, an arm 23, and a head 24.

[0015] The bed section 20 is disposed below the frame 2. The bed section 20 has an upper surface 20A. The upper surface 20A is parallel to a predetermined plane including the left-right direction (first direction) and the front-rear direction (second direction). The bed section 20 has an internal space.

[0016] The cylinder portion 21 protrudes leftward from the left end of the bed portion 20. The cylinder portion 21 has an upper surface 21A. In the left-right direction, the dimension of the cylinder portion 21 is smaller than the dimension of the bed portion 20. In the front-rear direction, the dimension of the cylinder portion 21 is smaller than the dimension of the bed portion 20. In the up-down direction, the dimension of the cylinder portion 21 is smaller than the dimension of the bed portion 20.

[0017] The upper surface 20A of the bed section 20 and the upper surface 21A of the cylinder section 21 are arranged in the same plane. That is, the upper surface 20A of the bed section 20 and the upper surface 21A of the cylinder section 21 are flush with each other. In the vertical direction, the upper surface 20A of the bed section 20 and the upper surface 21A of the cylinder section 21 are arranged at the same position. The lower surface of the cylinder section 21 is arranged higher than the lower surface of the bed section 20. The front surface of the cylinder section 21 is arranged rearward of the front surface of the bed section 20. The rear surface of the cylinder section 21 is arranged forward of the rear surface of the bed section 20.

[0018] The external shape of the cylinder portion 21 is substantially rectangular parallelepiped. The left-right dimension of the cylinder portion 21 is greater than the front-rear dimension and the up-down dimension of the cylinder portion 21. The front-rear dimension of the cylinder portion 21 is greater than the up-down dimension of the cylinder portion 21. Note that the front-rear dimension of the cylinder portion 21 may be smaller than the up-down dimension of the cylinder portion 21. The front-rear dimension of the cylinder portion 21 and the up-down dimension of the cylinder portion 21 may be the same.

[0019] The cylinder portion 21 has an internal space. The cylinder portion 21 has a main body portion 210 and a cover portion 211. The cover portion 211 is disposed so as to cover the opening of the main body portion 210. The cover portion 211 is detachable from the main body portion 210.

[0020] The main body 210 has a front plate 210A, a rear plate 210B, an upper plate 210C, and a lower plate 210D. The front plate 210A is disposed forward of the rear plate 210B. The front plate 210A and the rear plate 210B face each other across a gap. The front end of the upper plate 210C is connected to the upper end of the front plate 210A. The rear end of the upper plate 210C is connected to the upper end of the rear plate 210B. The lower plate 210D is disposed below the upper plate 210C. The upper plate 210C and the lower plate 210D face each other across a gap. The front end of the lower plate 210D is connected to the lower end of the front plate 210A. The rear end of the lower plate 210D is connected to the lower end of the rear plate 210B. The left end of the lower plate portion 210D is located to the left of the left end of the upper plate portion 210C. An opening is provided at the left end of the main body portion 210. An opening is provided at the left part of the upper end of the main body portion 210.

[0021] The cover part 211 is disposed so as to cover the opening of the main body part 210. The cover part 211 has a left plate part 211A that covers the opening at the left end part of the main body part 210, and an upper plate part 211B that covers the opening at the left part of the upper end part of the main body part 210. The upper end part of the left plate part 211A is connected to the left end part of the upper plate part 211B.

[0022] The upper surface 21A of the cylinder portion 21 includes the upper surface of the upper plate portion 210C of the main body portion 210 and the upper surface of the upper plate portion 211B of the cover portion 211. The upper surface of the upper plate portion 210C and the upper surface of the upper plate portion 211B of the cover portion 211 are arranged in the same plane. In other words, the upper surface of the upper plate portion 210C and the upper surface of the upper plate portion 211B of the cover portion 211 are flush with each other.

[0023] The body 22 extends upward from the right end of the bed 20. The arm 23 extends leftward from the upper end of the body 22. The head 24 protrudes downward from the left end of the arm 23. The body 22 connects the right end of the bed 20 to the right end of the arm 23. The bed 20 and the cylinder 21 are positioned below the arm 23 and the head 24. The arm 23 faces at least a portion of the bed 20. The head 24 faces at least a portion of the cylinder 21.

[0024] The needle bar 4 is supported by the head portion 24 so that it can move up and down. The needle bar 4 moves back and forth up and down while holding the sewing needle 3. The needle bar 4 holds the sewing needle 3 so that the sewing needle 3 and its vertical axis are parallel. The needle bar 4 is positioned above the needle plate 7 and can face the surface of the sewing object. An upper thread is threaded onto the sewing needle 3. The sewing needle 3 has a threading hole through which the upper thread passes. The sewing needle 3 holds the upper thread on the inner surface of the threading hole. As the needle bar 4 moves back and forth up and down, the sewing needle 3 moves back and forth up and down while holding the upper thread.

[0025] The take-up lever 5 supplies the upper thread to the sewing machine needle 3. The take-up lever 5 is supported by the head portion 24. The take-up lever 5 has a take-up hole through which the upper thread passes. The take-up lever 5 holds the upper thread on the inner surface of the take-up hole. The take-up lever 5 moves back and forth in the vertical direction while holding the upper thread. The take-up lever 5 moves back and forth in conjunction with the needle bar 4. The take-up lever 5 reciprocates the upper thread by moving back and forth in the vertical direction.

[0026] The thread tensioner 6 applies tension to the upper thread. The thread tensioner 6 adjusts the tension of the upper thread. The upper thread is supplied to the thread tensioner 6 from a thread supply source. In the path through which the upper thread passes, the thread take-up lever 5 is disposed between the sewing needle 3 and the thread tensioner 6. The thread tensioner 6 adjusts the tension of the upper thread supplied to the sewing needle 3 via the thread take-up lever 5.

[0027] The needle plate 7 supports the sewing object. The needle plate 7 is supported by the cylinder portion 21. In the left-right direction, the needle plate 7 is disposed between the upper plate portion 210C of the main body portion 210 and the upper plate portion 211B of the cover portion 211. The needle plate 7 faces the sewing needle 3 held by the needle bar 4. The needle plate 7 has a needle hole 70 through which the sewing needle 3 can pass. After penetrating the sewing object supported by the needle plate 7, the sewing needle 3 passes through the needle hole 70 in the needle plate 7.

[0028] The presser member 8 presses down the sewing object located at the sewing position PS directly below the sewing needle 3. The sewing position PS includes the so-called needle drop position where the sewing needle 3 passes through the sewing object. The sewing position PS includes the needle hole 70 of the needle plate 7. The presser member 8 is located above the needle plate 7. The presser member 8 faces the needle plate 7. The presser member 8 presses down the sewing object from above. The presser member 8 holds the sewing object between itself and the needle plate 7.

[0029] The shuttle 9 holds a bobbin (not shown) housed in a bobbin case. The bobbin case is housed in the shuttle 9. A bobbin thread is wound onto the bobbin. The shuttle 9 is disposed in the internal space of the cylinder portion 21. The shuttle 9 is disposed below the needle plate 7. The shuttle 9 rotates in conjunction with the needle bar 4. The shuttle 9 supplies the bobbin thread to the upper thread. The shuttle 9 penetrates the sewing object supported by the needle plate 7 and scoops up the upper thread from the sewing machine needle 3 that has passed through the needle eye of the needle plate 7.

[0030] The sewing machine motor 12 generates power. The sewing machine motor 12 is disposed at the right end of the arm portion 23. The power generated by the sewing machine motor 12 is transmitted to the needle bar 4, the thread take-up lever 5, and the shuttle 9 via a power transmission mechanism (not shown). The needle bar 4, the thread take-up lever 5, and the shuttle 9 are interlocked with each other. When the power generated by the sewing machine motor 12 is transmitted to the needle bar 4, the needle bar 4 and the sewing needle 3 held by the needle bar 4 move up and down in a reciprocating manner. When the power generated by the sewing machine motor 12 is transmitted to the thread take-up lever 5, the thread take-up lever 5 moves up and down in a reciprocating manner in conjunction with the needle bar 4. When the power generated by the sewing machine motor 12 is transmitted to the shuttle 9, the shuttle 9 rotates in conjunction with the needle bar 4 and the thread take-up lever 5. The sewing machine 1 sews an object to be sewn by cooperation between the sewing needle 3 held by the needle bar 4 and the shuttle 9.

[0031] <Upper feed mechanism> The upper feed mechanism 10 feeds the sewing object in the front-to-rear direction. The upper feed mechanism 10 is disposed above the cylinder portion 21. At least a portion of the upper feed mechanism 10 faces the upper surface 21A of the cylinder portion 21. At least a portion of the upper feed mechanism 10 faces the upper surface of the needle plate 7. The upper feed mechanism 10 includes a presser member 8.

[0032] The upper feed mechanism 10 includes a first upper feed belt 13, a second upper feed belt 14, a first upper feed motor 15, a second upper feed motor 16, a belt support mechanism 17, and a motor support mechanism 18.

[0033] The first upper feed belt 13 and the second upper feed belt 14 are each circular. The first upper feed belt 13 and the second upper feed belt 14 are each so-called endless belts. The first upper feed belt 13 and the second upper feed belt 14 are arranged in the left-right direction. The first upper feed belt 13 is arranged to the left of the sewing needle 3. The second upper feed belt 14 is arranged to the right of the sewing needle 3. The lower end of the first upper feed belt 13 is arranged to the left of the sewing position PS directly below the sewing needle 3. The lower end of the second upper feed belt 14 is arranged to the right of the sewing position PS directly below the sewing needle 3. The lower end of the first upper feed belt 13 and the lower end of the second upper feed belt 14 each contact the top surface of the sewing object. The first upper feed belt 13 and the second upper feed belt 14 each move to feed the sewing object forward. The first upper feed belt 13 rotates with its lower end in contact with the upper surface of the sewing object, allowing the first upper feed belt 13 to feed the sewing object. The second upper feed belt 14 rotates with its lower end in contact with the upper surface of the sewing object, allowing the second upper feed belt 14 to feed the sewing object.

[0034] The second upper feed belt 14 can move to feed the sewing object forward independently of the first upper feed belt 13. The second upper feed belt 14 can feed the sewing object at a feed amount (feed speed) different from the feed amount (feed speed) of the sewing object by the first upper feed belt 13.

[0035] The first upper feed motor 15 generates a rotational force for moving the first upper feed belt 13. The second upper feed motor 16 generates a rotational force for moving the second upper feed belt 14. A first upper feed sprocket 15A is connected to the first upper feed motor 15. A second upper feed sprocket 16A is connected to the second upper feed motor 16. The upper end of the first upper feed belt 13 is hooked onto the first upper feed sprocket 15A. The upper end of the second upper feed belt 14 is hooked onto the second upper feed sprocket 16A.

[0036] The belt support mechanism 17 supports each of the first upper feed belt 13 and the second upper feed belt 14. The belt support mechanism 17 includes a plurality of pulleys 17A that movably support each of the first upper feed belt 13 and the second upper feed belt 14, and a bracket 17B that supports the pulleys 17A. The pressing member 8 is supported on the lower end of the bracket 17B.

[0037] The motor support mechanism 18 supports each of the first upper feed motor 15 and the second upper feed motor 16. The motor support mechanism 18 supports each of the first upper feed sprocket 15A and the second upper feed sprocket 16A. The motor support mechanism 18 includes brackets 18A that support each of the first upper feed motor 15, the second upper feed motor 16, the first upper feed sprocket 15A, and the second upper feed sprocket 16A, and a fixing mechanism 18B that fixes the brackets 18A to the rear surface of the head unit 24. The upper part of the bracket 17B of the belt support mechanism 17 is fixed to the lower part of the bracket 18A of the motor support mechanism 18. The first upper feed belt 13 and the second upper feed belt 14 are supported by the head unit 24 via the belt support mechanism 17 and the motor support mechanism 18.

[0038] The first upper feed motor 15 is driven to rotate the first upper feed sprocket 15A in one direction, thereby rotating the first upper feed belt 13 in one direction. When the first upper feed belt 13 rotates in one direction, the lower surface of the lower end of the first upper feed belt 13, which comes into contact with the upper surface of the sewing object, moves forward, and the sewing object is fed forward by the first upper feed belt 13.

[0039] The second upper feed motor 16 is driven to rotate the second upper feed sprocket 16A in one direction, thereby rotating the second upper feed belt 14 in one direction. When the second upper feed belt 14 rotates in one direction, the lower surface of the lower end of the second upper feed belt 14, which comes into contact with the upper surface of the sewing object, moves forward, and the sewing object is fed forward by the second upper feed belt 14.

[0040] By providing a difference in rotation speed between the first upper feed motor 15 (first upper feed sprocket 15A) and the second upper feed motor 16 (second upper feed sprocket 16A), a difference is provided between the feed amount (feed speed) of the sewing object by the first upper feed belt 13 and the feed amount (feed speed) of the sewing object by the second upper feed belt 14. The second upper feed belt 14 can feed the sewing object at a feed amount (feed speed) different from the feed amount (feed speed) of the sewing object by the first upper feed belt 13.

[0041] The first upper feed belt 13 and the second upper feed belt 14 may each move so as to feed the sewing object rearward.

[0042] <Bottom feed mechanism> FIG. 3 is a perspective view from the upper left rear side showing the internal space of the cylinder portion 21 according to the embodiment. FIG. 4 is a perspective view from the upper left rear side showing a part of the lower feed mechanism 11A according to the embodiment. FIG. 5 is a bottom view showing the lower feed mechanism 11A according to the embodiment. FIG. 6 is a left side view showing the lower feed mechanism 11A according to the embodiment, and corresponds to the cross-sectional view taken along line AA in FIG. 5. FIG. 7 is a perspective view from the upper left rear side showing the lower feed mechanism 11A according to the embodiment.

[0043] The bottom feed mechanism 11A feeds the sewing object in the front-to-rear direction. At least a portion of the bottom feed mechanism 11A is disposed in the internal space of the cylinder portion 21. At least a portion of the bottom feed mechanism 11A is disposed directly below the needle plate 7. At least a portion of the bottom feed mechanism 11A faces the underside of the needle plate 7. At least a portion of the bottom feed mechanism 11A is disposed in the internal space of the bed portion 20.

[0044] The lower feed mechanism 11A has a first lower feed belt 31, a second lower feed belt 32, a first lower feed sprocket 33, a second lower feed sprocket 34, a first lower feed motor 35, a second lower feed motor 36, a first lower feed shaft 37, and a second lower feed shaft 38.

[0045] The first lower feed belt 31 and the second lower feed belt 32 are each circular. The first lower feed belt 31 and the second lower feed belt 32 are each so-called endless belts. The first lower feed belt 31 and the second lower feed belt 32 are arranged in the left-right direction. The first lower feed belt 31 is arranged to the left of the sewing needle 3. The second lower feed belt 32 is arranged to the right of the sewing needle 3. The upper end of the first lower feed belt 31 is arranged to the left of the sewing position PS directly below the sewing needle 3. The upper end of the second lower feed belt 32 is arranged to the right of the sewing position PS directly below the sewing needle 3. The sewing position PS includes the needle hole 70 of the needle plate 7 through which the sewing needle 3 passes.

[0046] The upper end of the first lower feed belt 31 is positioned in an opening 71 provided in the needle plate 7. The upper end of the second lower feed belt 32 is positioned in an opening 72 provided in the needle plate 7. The opening 71 is provided to the left of the needle hole 70. The opening 72 is provided to the right of the needle hole 70. The upper end of the first lower feed belt 31 comes into contact with the underside of the sewing object through the opening 71 in the needle plate 7. The upper end of the second lower feed belt 32 comes into contact with the underside of the sewing object through the opening 72 in the needle plate 7.

[0047] The first lower feed belt 31 and the second lower feed belt 32 each move to feed the sewing object forward. The first lower feed belt 31 rotates with the upper end of the first lower feed belt 31 in contact with the underside of the sewing object, allowing the first lower feed belt 31 to feed the sewing object. The second lower feed belt 32 rotates with the upper end of the second lower feed belt 32 in contact with the underside of the sewing object, allowing the second lower feed belt 32 to feed the sewing object.

[0048] The second lower feed belt 32 can move to feed the sewing object forward independently of the first lower feed belt 31. The second lower feed belt 32 can feed the sewing object at a feed amount (feed speed) different from the feed amount (feed speed) of the sewing object by the first lower feed belt 31.

[0049] Two first lower feed belts 31 are provided. The first lower feed belts 31 include a first lower feed belt 31A and a first lower feed belt 31B that is positioned to the left of the first lower feed belt 31A. The first lower feed belt 31A and the first lower feed belt 31B are each positioned to the left of the sewing position PS directly below the sewing needle 3. The opening 71 of the needle plate 7 includes an opening 71A where the upper end of the first lower feed belt 31A is positioned, and an opening 71B where the upper end of the first lower feed belt 31B is positioned.

[0050] Two second lower feed belts 32 are provided. The second lower feed belts 32 include a second lower feed belt 32A and a second lower feed belt 32B that is positioned to the right of the second lower feed belt 32A. The second lower feed belt 32A and the second lower feed belt 32B are each positioned to the right of the sewing position PS directly below the sewing needle 3. The opening 72 of the needle plate 7 includes an opening 72A in which the upper end of the second lower feed belt 32A is positioned, and an opening 72B in which the upper end of the second lower feed belt 32B is positioned.

[0051] The first lower feed belt 31 and the second lower feed belt 32 are disposed in the internal space of the cylinder portion 21. At least a portion of the first lower feed belt 31 is disposed directly below the needle plate 7. At least a portion of the second lower feed belt 32 is disposed directly below the needle plate 7.

[0052] The lower part of the first lower feed belt 31 is hooked around a first lower feed sprocket 33. The lower part of the second lower feed belt 32 is hooked around a second lower feed sprocket 34. The first lower feed sprocket 33 rotates while supporting the first lower feed belt 31, thereby moving the first lower feed belt 31. The second lower feed sprocket 34 rotates while supporting the second lower feed belt 32, thereby moving the second lower feed belt 32. The first lower feed sprocket 33 and the second lower feed sprocket 34 are disposed in the internal space of the cylinder portion 21.

[0053] The first lower feed sprocket 33 and the second lower feed sprocket 34 are arranged in the front-to-rear direction in the internal space of the cylinder portion 21. The first lower feed sprocket 33 is arranged forward of the second lower feed sprocket 34. In the left-right direction, the position of the first lower feed sprocket 33 and the position of at least a portion of the second lower feed sprocket 34 are the same. In the up-down direction, the position of the first lower feed sprocket 33 and the position of at least a portion of the second lower feed sprocket 34 are the same.

[0054] The shuttle 9 is disposed in the internal space of the cylinder portion 21. Power generated by the sewing machine motor 12 is transmitted to the shuttle 9 via the shuttle shaft 19. The transmission of the power generated by the sewing machine motor 12 to the shuttle 9 causes the shuttle 9 to rotate in conjunction with the needle bar 4 and the thread take-up lever 5. A guide member 30 is disposed around the shuttle 9. The guide member 30 is annular. The guide member 30 supports a first lower feed belt 31 and a second lower feed belt 32. The first lower feed belt 31 is disposed around the guide member 30. The second lower feed belt 32 is disposed around the guide member 30. When the first lower feed sprocket 33 rotates, the first lower feed belt 31 rotates while being guided by the guide member 30. When the second lower feed sprocket 34 rotates, the second lower feed belt 32 rotates while being guided by the guide member 30. The shuttle 9 and the guide member 30 are disposed inside the first circular lower feed belt 31 and inside the second circular lower feed belt 32.

[0055] By removing the cover portion 211 from the main body portion 210, the user of the sewing machine 1 can replace the bobbin in the shuttle 9, re-hook the first lower feed belt 31, or re-hook the second lower feed belt 32.

[0056] The first lower feed motor 35 generates a rotational force for moving the first lower feed belt 31. The second lower feed motor 36 generates a rotational force for moving the second lower feed belt 32. In the embodiment, the first lower feed motor 35 generates a rotational force for rotating the first lower feed sprocket 33. The second lower feed motor 36 generates a rotational force for rotating the second lower feed sprocket 34. The first lower feed motor 35 and the second lower feed motor 36 are disposed in the internal space of the bed portion 20.

[0057] The first lower feed motor 35 has a stator 35A supported by the bed portion 20 and a rotor shaft 35B that rotates inside the stator 35A. The left end of the rotor shaft 35B protrudes leftward from the stator 35A. The second lower feed motor 36 has a stator 36A supported by the bed portion 20 and a rotor shaft 36B that rotates inside the stator 36A. The left end of the rotor shaft 36B protrudes leftward from the stator 36A.

[0058] The rotation axis CX1 of the rotor shaft 35B of the first lower feed motor 35 and the rotation axis CX2 of the rotor shaft 36B of the second lower feed motor 36 extend in the left-right direction. The rotation axis CX1 and the rotation axis CX2 are parallel to each other.

[0059] The rotor shaft 35B of the first lower feed motor 35 is connected to the first lower feed shaft 37 via a first coupling 39. The rotor shaft 36B of the second lower feed motor 36 is connected to the second lower feed shaft 38 via a second coupling 40. The first lower feed shaft 37 and the second lower feed shaft 38 each extend in the left-right direction. The first lower feed shaft 37 is rotatably supported by a first bearing 41. The second lower feed shaft 38 is rotatably supported by a second bearing 42. The first bearing 41 and the second bearing 42 are each held by the bed portion 20.

[0060] The left end of the first lower feed shaft 37 is connected to the first lower feed sprocket 33 in the internal space of the cylinder part 21. The left end of the second lower feed shaft 38 is connected to the second lower feed sprocket 34 in the internal space of the cylinder part 21.

[0061] The rotation axis of the first lower feed shaft 37 and the rotation axis of the first lower feed sprocket 33 coincide with the rotation axis CX1 of the first lower feed motor 35. The rotation axis of the second lower feed shaft 38 and the rotation axis of the second lower feed sprocket 34 coincide with the rotation axis CX2 of the second lower feed motor 36.

[0062] The first lower feed motor 35 is driven to rotate the first lower feed shaft 37 in one direction, which causes the first lower feed sprocket 33 to rotate in one direction. The first lower feed sprocket 33 rotates in one direction, which causes the first lower feed belt 31 to rotate in one direction. When the first lower feed belt 31 rotates in one direction, the upper surface of the upper end of the first lower feed belt 31, which comes into contact with the lower surface of the sewing object, moves forward, and the sewing object is fed forward by the first lower feed belt 31.

[0063] The second lower feed motor 36 is driven to rotate the second lower feed shaft 38 in one direction, which causes the second lower feed sprocket 34 to rotate in one direction. The second lower feed sprocket 34 rotates in one direction, which causes the second lower feed belt 32 to rotate in one direction. When the second lower feed belt 32 rotates in one direction, the upper surface of the upper end of the second lower feed belt 32, which comes into contact with the lower surface of the sewing object, moves forward, and the sewing object is fed forward by the second lower feed belt 32.

[0064] By providing a difference in rotation speed between the first lower feed motor 35 (first lower feed sprocket 33) and the second lower feed motor 36 (second lower feed sprocket 34), a difference is provided between the feed amount (feed speed) of the sewing object by the first lower feed belt 31 and the feed amount (feed speed) of the sewing object by the second lower feed belt 32. The second lower feed belt 32 can feed the sewing object at a feed amount (feed speed) different from the feed amount (feed speed) of the sewing object by the first lower feed belt 31.

[0065] The first lower feed belt 31 and the second lower feed belt 32 may each move so as to feed the sewing object rearward.

[0066] The first lower feed motor 35 and the second lower feed motor 36 are arranged at different positions in the left-right direction. The second lower feed motor 36 is arranged to the left of the first lower feed motor 35. The position of the first lower feed motor 35 and the position of at least a part of the body portion 22 are the same in the left-right direction. The position of the second lower feed motor 36 and the position of the body portion 22 are different in the left-right direction. In a predetermined plane parallel to the upper surface 20A, the first lower feed motor 35 and the body portion 22 overlap. The first lower feed motor 35 is arranged directly below the body portion 22. In a predetermined plane parallel to the upper surface 20A, the second lower feed motor 36 and the body portion 22 do not overlap. The second lower feed motor 36 is arranged to the left of the body portion 22. The second lower feed motor 36 is arranged at a position closer to the cylinder portion 21 than the first lower feed motor 35.

[0067] In the front-rear direction, the position of the first lower feed motor 35 and the position of at least a part of the second lower feed motor 36 are the same. In the front-rear direction, the first lower feed motor 35 and the position of at least a part of the second lower feed motor 36 overlap. In the front-rear direction, the position of the stator 35A of the first lower feed motor 35 and the position of at least a part of the stator 36A of the second lower feed motor 36 are the same. In the front-rear direction, the position of the rotor shaft 35B of the first lower feed motor 35 and the position of the rotor shaft 36B of the second lower feed motor 36 are different.

[0068] In the vertical direction, the position of the first lower feed motor 35 is the same as the position of at least a part of the second lower feed motor 36. The first lower feed motor 35 and the second lower feed motor 36 are disposed at the same height.

[0069] <controller> 8 is a block diagram showing the controller 50 of the sewing machine 1 according to the embodiment. The sewing machine 1 is equipped with the controller 50. The controller 50 includes a computer. The controller 50 controls at least the sewing machine motor 12, the first upper feed motor 15, the second upper feed motor 16, the first lower feed motor 35, and the second lower feed motor 36.

[0070] The controller 50 has a processor 51 such as a CPU (Central Processing Unit), a main memory 52 including a non-volatile memory such as a ROM (Read Only Memory) and a volatile memory such as a RAM (Random Access Memory), a storage 53, and an input / output interface 54 including an input / output circuit. The functions of the controller 50 are stored in the storage 53 as a computer program. The processor 51 reads the computer program from the storage 53, loads it into the main memory 52, and executes processing in accordance with the computer program. The computer program may be distributed to the controller 50 via a network.

[0071] The input / output interface 54 is connected to each of the sewing machine motor 12, the first upper feed motor 15, the second upper feed motor 16, the first lower feed motor 35, and the second lower feed motor 36. An operation panel 55 is also connected to the input / output interface 54. The operation panel 55 has the functions of a display device and an input device. The operation panel 55 includes a touch panel.

[0072] <Sewing machine operation> Next, the operation of the sewing machine 1 will be described. The sewing object is cylindrical. An example of the sewing object is a sleeve of a garment. The user of the sewing machine 1 places the cylindrical sewing object at the sewing position PS so that the cylinder 21 is inserted inside the sewing object. After being placed at the sewing position PS, the sewing object is pressed down from above by the presser member 8. The sewing object is sandwiched between the first upper feed belt 13 and the first lower feed belt 31 to the left of the sewing position PS. The sewing object is sandwiched between the second upper feed belt 14 and the second lower feed belt 32 to the left of the sewing position PS. The first upper feed belt 13 contacts the top surface of the sewing position PS to the left of the sewing position PS. The second upper feed belt 14 contacts the top surface of the sewing position PS to the right of the sewing position PS. The first lower feed belt 31 contacts the bottom surface of the sewing position PS to the left of the sewing position PS. The second lower feed belt 32 comes into contact with the lower surface of the sewing position PS on the right side of the sewing position PS.

[0073] The user operates an operating member (not shown) to start sewing the sewing object. The controller 50 controls the sewing machine motor 12 so that the sewing needle 3 moves up and down and the shuttle 9 rotates. The controller 50 also controls the first upper feed motor 15, the second upper feed motor 16, the first lower feed motor 35, and the second lower feed motor 36 to adjust the feed amounts of the first upper feed belt 13, the second upper feed belt 14, the first lower feed belt 31, and the second lower feed belt 32, respectively. The controller 50 controls the first upper feed motor 15 and the first lower feed motor 35 so that the feed amount of the first upper feed belt 13 matches the feed amount of the first lower feed belt 31. The controller 50 controls the second upper feed motor 16 and the second lower feed motor 36 so that the feed amount of the second upper feed belt 14 matches the feed amount of the second lower feed belt 32.

[0074] 9A and 9B are diagrams illustrating stitches formed on a sewing object according to an embodiment. As shown in Fig. 9A, when forming a linear stitch SE on a sewing object, the controller 50 controls the first upper feed motor 15, the second upper feed motor 16, the first lower feed motor 35, and the second lower feed motor 36 so that the feed amount by the first upper feed belt 13 and the first lower feed belt 31 is the same as the feed amount by the second upper feed belt 14 and the second lower feed belt 32.

[0075] As shown in Figure 9 (B), when a curved seam SE that curves to the left is formed on the sewing object, the controller 50 controls the first upper feed motor 15, the second upper feed motor 16, the first lower feed motor 35, and the second lower feed motor 36 so that the feed amount by the first upper feed belt 13 and the first lower feed belt 31 is greater than the feed amount by the second upper feed belt 14 and the second lower feed belt 32.

[0076] As shown in Figure 9 (C), when a curved seam SE that curves to the right side is formed on the sewing object, the controller 50 controls the first upper feed motor 15, the second upper feed motor 16, the first lower feed motor 35, and the second lower feed motor 36 so that the feed amount by the second upper feed belt 14 and the second lower feed belt 32 is greater than the feed amount by the first upper feed belt 13 and the first lower feed belt 31.

[0077] A user of the sewing machine 1 can change the shape of the seam SE by operating the operation panel 55. The controller 50 adjusts the feed amount by the first upper feed belt 13 and the first lower feed belt 31 and the feed amount by the second upper feed belt 14 and the second lower feed belt 32 based on an operation signal from the operation panel 55.

[0078] <Effects> As described above, in the embodiment, the sewing machine 1 is a frame having the bed portion 20 having the upper surface 20A, the cylinder portion 21 protruding leftward from the bed portion 20 in the left-right direction of a predetermined plane parallel to the upper surface 20A and having a dimension in the front-rear direction perpendicular to the left-right direction on the predetermined plane that is smaller than that of the bed portion 20, the body portion 22 extending upward from the bed portion 20 in the up-down direction perpendicular to the predetermined plane, the arm portion 23 extending leftward from the upper end of the body portion 22 in the left-right direction, and the head portion 24 protruding downward from the arm portion 23. The sewing machine includes a cylinder 2, a needle bar 4 that is movably supported on the head portion 24 and moves back and forth in the vertical direction while holding a sewing needle 3 that holds an upper thread, a presser member 8 that presses down an object to be sewn that is positioned at a sewing position PS directly below the sewing needle 3, a circular first lower feed belt 31 that is positioned on the left side of the sewing position PS in the horizontal direction and moves to feed the object to be sewn in the front-to-back direction, and a circular second lower feed belt 32 that is positioned on the right side of the sewing position PS and moves to feed the object to be sewn in the front-to-back direction independently of the first lower feed belt 31. The first lower feed belt 31 and the second lower feed belt 32 are disposed in the internal space of the cylinder portion 21.

[0079] According to the embodiment, the first lower feed belt 31 and the second lower feed belt 32 are disposed in the internal space of the cylinder portion 21, and therefore, as described with reference to Fig. 9, the shape of the seam SE is adjusted by adjusting the feed amount of the first lower feed belt 31 and the feed amount of the second lower feed belt 32. Because the first lower feed belt 31 and the second lower feed belt 32 are disposed in the internal space of the cylinder portion 21, the sewing machine 1 can adjust the shape of the seam SE to be formed on a tubular sewing object such as a sleeve.

[0080] The sewing machine 1 includes a shuttle 9 that houses a bobbin case that holds a bobbin wound with a bobbin thread and supplies the bobbin thread to the upper thread. The shuttle 9 is disposed inside the first lower feed belt 31 and the second lower feed belt 32 in the internal space of the cylinder portion 21.

[0081] Since the shuttle 9 is provided in the internal space of the cylinder portion 21, the bobbin thread is smoothly supplied to a cylindrical sewing object such as a sleeve. Since the shuttle 9 is disposed inside the first lower feed belt 31 and inside the second lower feed belt 32, the cylinder portion 21 does not need to be large.

[0082] The sewing machine 1 includes a first lower feed sprocket 33 that rotates while supporting the first lower feed belt 31, thereby moving the first lower feed belt 31, and a second lower feed sprocket 34 that rotates while supporting the second lower feed belt 32, thereby moving the second lower feed belt 32. The first lower feed sprocket 33 and the second lower feed sprocket 34 are disposed in the internal space of the cylinder portion 21.

[0083] Since the first lower feed sprocket 33 and the second lower feed sprocket 34 are arranged in the internal space of the cylinder section 21, the first lower feed belt 31 and the second lower feed belt 32 can each rotate while preventing the cylinder section 21 from becoming too large.

[0084] The first lower feed sprocket 33 and the second lower feed sprocket 34 are arranged in the front-to-rear direction. In the up-down direction, the position of the first lower feed sprocket 33 and the position of at least a portion of the second lower feed sprocket 34 are the same.

[0085] In the vertical direction, the position of the first lower feed sprocket 33 and the position of at least a part of the second lower feed sprocket 34 are the same, so that an increase in size of the cylinder portion 21 in the vertical direction is suppressed.

[0086] The sewing machine 1 includes a first bottom feed motor 35 that generates a rotational force for rotating the first bottom feed sprocket 33, and a second bottom feed motor 36 that generates a rotational force for rotating the second bottom feed sprocket 34. The first bottom feed motor 35 and the second bottom feed motor 36 are disposed in the internal space of the bed portion 20.

[0087] Since the first lower feed motor 35 and the second lower feed motor 36 are disposed in the internal space of the bed portion 20 and not in the cylinder portion 21, the cylinder portion 21 is prevented from becoming large.

[0088] The first lower feed motor 35 and the second lower feed motor 36 are disposed at different positions in the left-right direction.

[0089] Since the first lower feed motor 35 and the second lower feed motor 36 are disposed at different positions in the left-right direction, interference between the first lower feed motor 35 and the second lower feed motor 36 is suppressed.

[0090] In the front-rear direction, the position of the first lower feed motor 35 and the position of at least a part of the second lower feed motor 36 are the same.

[0091] In the front-rear direction, the position of the first lower feed motor 35 and the position of at least a portion of the second lower feed motor 36 are the same, which prevents the bed section 20 from becoming larger in size in the front-rear direction. Furthermore, in the front-rear direction, the stator 35A of the first lower feed motor 35 and the stator 36A of the second lower feed motor 36 overlap, which reduces the distance between the first lower feed sprocket 33 and the second lower feed sprocket 34. In other words, the first lower feed sprocket 33 and the second lower feed sprocket 34 can be brought closer to each other in the front-rear direction. This prevents the cylinder section 21 from becoming larger in size in the front-rear direction.

[0092] The first lower feed motor 35 is disposed directly below the body portion 22. The second lower feed motor 36 is disposed at a position 35 closer to the cylinder portion 21 than the first lower feed motor.

[0093] The first lower feed motor 35 is positioned directly below the body portion 22, and the second lower feed motor 36 is positioned 35 times closer to the cylinder portion 21 than the first lower feed motor, thereby suppressing interference between the first lower feed motor 35 and the second lower feed motor 36.

[0094] In the vertical direction, the position of the first lower feed motor 35 and the position of at least a part of the second lower feed motor 36 are the same.

[0095] In the vertical direction, the position of the first lower feed motor 35 and the position of at least a part of the second lower feed motor 36 are the same, so that the bed portion 20 is prevented from becoming large in size in the vertical direction.

[0096] [Second embodiment] A second embodiment will be described below. In the following description, the same or equivalent components as those in the above-described embodiment will be denoted by the same reference numerals, and the description of those components will be simplified or omitted.

[0097] Fig. 10 is a bottom view showing the lower feed mechanism 11B according to the embodiment, and Fig. 11 is a perspective view showing the lower feed mechanism 11B according to the embodiment, seen from the upper left rear side.

[0098] The lower feed mechanism 11B has a first lower feed belt 31, a first lower feed sprocket 33 on which the first lower feed belt 31 is wound, a second lower feed belt 32, and a second lower feed sprocket 34 on which the second lower feed belt 32 is wound.

[0099] The lower feed mechanism 11B also has a first input shaft 37A connected to the first lower feed sprocket 33, a first output shaft 37B connected to the rotor shaft 35B of the first lower feed motor 35 via a first coupling 39, a second input shaft 38A connected to the second lower feed sprocket 34, and a second output shaft 38B connected to the rotor shaft 36B of the second lower feed motor 36 via a second coupling 40. The first input shaft 37A is rotatably supported by a first bearing 41. The second input shaft 38A is rotatably supported by a second bearing 42. The first bearing 41 and the second bearing 42 are each supported by the bed portion 20.

[0100] In addition, the lower feed mechanism 11B has a first transmission mechanism 37C that transmits the rotational force of the first output shaft 37B to the first input shaft 37A, and a second transmission mechanism 38C that transmits the rotational force of the second output shaft 38B to the second input shaft 38A.

[0101] The first transmission mechanism 37C includes a circular belt. The first transmission mechanism 37C includes a so-called endless belt. A first input sprocket 37D is fixed to the right end of the first input shaft 37A. A first output sprocket 37E is fixed to the left end of the first output shaft 37B. The belt of the first transmission mechanism 37C is looped around the first input sprocket 37D and the first output sprocket 37E.

[0102] The second transmission mechanism 38C includes a circular belt. The second transmission mechanism 38C includes a so-called endless belt. A second input sprocket 38D is fixed to the right end of the second input shaft 38A. A second output sprocket 38E is fixed to the left end of the second output shaft 38B. The belt of the second transmission mechanism 38C is looped around the second input sprocket 38D and the second output sprocket 38E.

[0103] In the front-rear direction, the distance between the first input shaft 37A and the second input shaft 38A is shorter than the distance between the first output shaft 37B and the second output shaft 38B.

[0104] The rotation axis CX1 of the first bottom feed motor 35 is different from the rotation axis DX1 of the first bottom feed sprocket 33. The rotation axis CX2 of the second bottom feed motor 36 is different from the rotation axis DX2 of the second bottom feed sprocket 34. In the front-to-rear direction, the distance between the rotation axis DX1 and the rotation axis DX2 is shorter than the distance between the rotation axis CX1 and the rotation axis CX2.

[0105] In the front-rear direction, the position of the first lower feed motor 35 and the position of the second lower feed motor 36 are different. In the left-right direction, the position of the first lower feed motor 35 and the position of at least a part of the second lower feed motor 36 are the same. In the up-down direction, the position of the first lower feed motor 35 and the position of at least a part of the second lower feed motor 36 are the same.

[0106] As described above, in the embodiment, the lower feed mechanism 11B comprises a first input shaft 37A connected to the first lower feed sprocket 33, a second input shaft 38A connected to the second lower feed sprocket 34, a first output shaft 37B connected to the first lower feed motor 35, a second output shaft 38B connected to the second lower feed motor 36, a first transmission mechanism 37C that transmits the rotational force of the first output shaft 37B to the first input shaft 37A, and a second transmission mechanism 38C that transmits the rotational force of the second output shaft 38B to the second input shaft 38A.

[0107] According to the embodiment, even if the distance between the first lower feed motor 35 (first output shaft 37B) and the second lower feed motor 36 (second output shaft 38B) is long in the front-rear direction, the distance between the first lower feed sprocket 33 (first input shaft 37A) and the second lower feed sprocket 34 (second input shaft 38A) can be shortened. This prevents the cylinder unit 21 from becoming too large in the front-rear direction.

[0108] The first transmission mechanism 37C that transmits the rotational force of the first output shaft 37B to the first input shaft 37A may include at least one gear. The second transmission mechanism 38C that transmits the rotational force of the second output shaft 38B to the second input shaft 38A may include at least one gear.

[0109] [Third embodiment] A third embodiment will be described below. In the following description, the same or equivalent components as those in the above-described embodiment are denoted by the same reference numerals, and the description of these components will be simplified or omitted.

[0110] Fig. 12 is a bottom view showing the lower feed mechanism 11C according to the embodiment. Fig. 13 is a left side view showing the lower feed mechanism 11C according to the embodiment, and corresponds to a cross-sectional view taken along line BB in Fig. 12. Fig. 14 is a perspective view showing the lower feed mechanism 11C according to the embodiment, seen from the upper left rear side.

[0111] The lower feed mechanism 11C has a first lower feed belt 31, a first lower feed sprocket 33 around which the first lower feed belt 31 is wound, a second lower feed belt 32, and a second lower feed sprocket 34 around which the second lower feed belt 32 is wound. The first lower feed belt 31, the first lower feed sprocket 33, the second lower feed belt 32, and the second lower feed sprocket 34 are each disposed in the internal space of the cylinder portion 21C.

[0112] In this embodiment, the rotation axis DX1 of the first bottom feed sprocket 33 and the rotation axis DX2 of the second bottom feed sprocket 34 coincide with each other.

[0113] The lower feed mechanism 11C also has a first lower feed shaft 37 connected to the rotor shaft 35B of the first lower feed motor 35 via a first coupling 39, and a second lower feed shaft 38 connected to the rotor shaft 36B of the second lower feed motor 36 via a second coupling 40.

[0114] Fig. 15 is a rear view showing a part of the lower feed mechanism 11C according to the embodiment. Fig. 16 is a cross-sectional view showing a part of the lower feed mechanism 11C according to the embodiment. Fig. 15 corresponds to a view of the lower feed mechanism 11C from the rear side in Fig. 14, in which the second lower feed motor 36, the second lower feed shaft 38, and the second bearing 42 are omitted. In Fig. 15, the first bearing 41 is omitted. Fig. 16 corresponds to a cross-sectional view of Fig. 15.

[0115] The first lower feed sprocket 33 is fixed to the left end of the first lower feed shaft 37. The first lower feed shaft 37 functions as a first input shaft that rotates by the rotational force generated by the first lower feed motor 35.

[0116] The second lower feed sprocket 34 is fixed to the left end of the second input shaft 381. The second input shaft 381 rotates by the rotational force generated by the second lower feed motor 36. The second input shaft 381 is cylindrical. The second input shaft 381 is cylindrical. The first lower feed shaft 37 is disposed inside the second input shaft 381.

[0117] As shown in Figures 12 and 14, an output sprocket 382 is fixed to the second lower feed shaft 38. An input sprocket 383 is fixed to the second input shaft 381. The rotational force of the output sprocket 382 is transmitted to the input sprocket 383 via a transmission mechanism 384. The transmission mechanism 384 includes a belt that is looped around the output sprocket 382 and the input sprocket 383. The belt is a so-called endless belt. The transmission mechanism 384 may include at least one gear.

[0118] As shown in FIG. 13, the shuttle 9 is disposed above the first lower feed shaft 37.

[0119] The second input shaft 381 is rotatably supported by a first bearing 41. The second lower feed shaft 38 is rotatably supported by a second bearing 42. The first bearing 41 and the second bearing 42 are each supported by the bed portion 20.

[0120] When the first lower feed motor 35 is driven and the first lower feed shaft 37 rotates, the first lower feed sprocket 33 fixed to the left end of the first lower feed shaft 37 rotates. The first lower feed sprocket 33 rotates inside the second input shaft 381. The rotation of the first lower feed sprocket 33 causes the first lower feed belt 31 to move so as to feed the sewing object.

[0121] When the second lower feed motor 36 is driven and the second lower feed shaft 38 rotates, the output sprocket 382 fixed to the second lower feed shaft 38 rotates. The rotational force of the output sprocket 382 is transmitted to the input sprocket 383 via a transmission mechanism 384. The input sprocket 383 rotates due to the rotational force of the output sprocket 382. When the input sprocket 383 rotates, the second input shaft 381 to which the input sprocket 383 is fixed rotates. The second input shaft 381 and the first lower feed shaft 37 are rotatable relative to each other. When the second input shaft 381 rotates, the second lower feed sprocket 34 fixed to the left end of the second input shaft 381 rotates. The rotation of the second lower feed sprocket 34 causes the second lower feed belt 32 to move so as to feed the sewing object.

[0122] As described above, according to the embodiment, the second input shaft 381 is cylindrical. The first lower feed shaft 37 (first input shaft) is disposed inside the second input shaft 381. The second input shaft 381 and the first lower feed shaft 37 are rotatable relative to each other.

[0123] According to the embodiment, the size of the lower feed mechanism 11C is prevented from increasing, and the size of the cylinder portion 21C is also prevented from increasing.

[0124] [Variations] 17, 18, 19, and 20 are bottom views showing the bottom feed mechanisms according to the modified examples.

[0125] 17, the positions of the first lower feed motor 35 and the second lower feed motor 36 are different in the left-right direction. In a predetermined plane parallel to the upper surface 20A, the first lower feed motor 35 and the body 22 overlap. In a predetermined plane parallel to the upper surface 20A, at least a portion of the second lower feed motor 36 and the body 22 may overlap.

[0126] 18, the first lower feed motor 35 and the second lower feed motor 36 may be positioned in the same position in the left-right direction. The first lower feed motor 35 and the second lower feed motor 36 are arranged in the front-rear direction. In a predetermined plane parallel to the upper surface 20A, the first lower feed motor 35 and the second lower feed motor 36 overlap with the body 22.

[0127] As shown in FIG. 19, the dimension of the cylinder portion 21 may be larger than the dimension of the bed portion 20 in the left-right direction.

[0128] As shown in FIG. 20, the cylinder portion 21 may include a first portion 21X that protrudes leftward from the left end of the bed portion 20, and a second portion 21Y that protrudes rearward or forward from the left end of the first portion 21X. [Explanation of symbols]

[0129] 1... sewing machine, 2... frame, 3... sewing machine needle, 4... needle bar, 5... thread take-up lever, 6... thread tension controller, 7... throat plate, 8... presser foot, 9... shuttle, 10... upper feed mechanism, 11A... lower feed mechanism, 11B... lower feed mechanism, 11C... lower feed mechanism, 12... sewing machine motor, 13... first upper feed belt, 14... second upper feed belt, 15... first upper feed motor, 15A... first upper feed sprocket, 16... second upper feed motor, 16A... second upper feed sprocket, 17... belt support mechanism, 17A... pulley, 17B... bracket, 18... motor support mechanism, 18A... bracket, 18B... fixing mechanism, 19... shuttle shaft 1. Lift, 20...bed portion, 20A...upper surface, 21...cylinder portion, 21A...upper surface, 21C...cylinder portion, 21X...first portion, 21Y...second portion, 22...body portion, 23...arm portion, 24...head portion, 30...guide member, 31...first lower feed belt, 31A...first lower feed belt, 31B...first lower feed belt, 32...second lower feed belt, 32A...second lower feed belt, 32B...second lower feed belt, 33...first lower feed sprocket, 34...second lower feed sprocket, 35...first lower feed motor, 35A...stator, 35B...rotor shaft, 36...second lower feed motor, 36A... Stator, 36B...rotor shaft, 37...first lower feed shaft, 37A...first input shaft, 37B...first output shaft, 37C...first transmission mechanism, 37D...first input sprocket, 37E...first output sprocket, 38...second lower feed shaft, 38A...second input shaft, 38B...second output shaft, 38C...second transmission mechanism, 38D...second input sprocket, 38E...second output sprocket, 39...first coupling, 40...second coupling, 41...first bearing, 42...second bearing, 50...controller, 51...processor, 52...main Memory, 53...storage, 54...input / output interface, 55...operation panel, 70...needle hole, 71...opening, 71A...opening, 71B...opening, 72...opening, 72A...opening, 72B...opening, 210...main body, 210A...front plate, 210B...rear plate, 210C...upper plate, 210D...lower plate, 211...cover, 211A...left plate, 211B...upper plate, 381...second input shaft, 382...output sprocket, 383...input sprocket, 384...transmission mechanism, CX1...rotation shaft, CX2...rotation shaft, DX1...rotation shaft, DX2...rotation shaft, PS...sewing position, SE...stitch.

Claims

1. a frame including: a bed portion having an upper surface; a cylinder portion protruding from the bed portion to one side in a first direction of a predetermined plane parallel to the upper surface and having a dimension smaller than that of the bed portion in a second direction perpendicular to the first direction on the predetermined plane; a body portion extending upward from the bed portion in a third direction perpendicular to the predetermined plane; an arm portion extending from an upper end of the body portion to one side in the first direction; and a head portion protruding downward from the arm portion; a needle bar that is movably supported on the head portion and that reciprocates in the third direction while holding a sewing machine needle that holds an upper thread; a presser member that presses down an object to be sewn, the presser member being disposed at a sewing position directly below the sewing needle; a first annular lower feed belt that is disposed on one side of the sewing position in the first direction and moves to feed the sewing object in the second direction, and a second annular lower feed belt that is disposed on the other side of the sewing position and moves to feed the sewing object in the second direction independently of the first lower feed belt, the first lower feed belt and the second lower feed belt are disposed in the internal space of the cylinder portion; sewing machine.

2. a bobbin case for holding a bobbin wound with a lower thread and a hook for supplying the lower thread to the upper thread; the shuttle is disposed inside the first lower feed belt and the second lower feed belt in the internal space of the cylinder portion; 2. The sewing machine according to claim 1.

3. a first lower feed sprocket that rotates while supporting the first lower feed belt, thereby moving the first lower feed belt; a second lower feed sprocket that rotates while supporting the second lower feed belt to move the second lower feed belt; the first lower feed sprocket and the second lower feed sprocket are disposed in the internal space of the cylinder portion; 2. The sewing machine according to claim 1.

4. the first lower feed sprocket and the second lower feed sprocket are arranged in the second direction, In the third direction, a position of the first lower feed sprocket and a position of at least a portion of the second lower feed sprocket are the same.

4. The sewing machine according to claim 3.

5. a first lower feed motor that generates a rotational force for rotating the first lower feed sprocket; a second lower feed motor that generates a rotational force for rotating the second lower feed sprocket, the first lower feed motor and the second lower feed motor are disposed in the internal space of the bed portion; 4. The sewing machine according to claim 3.

6. In the first direction, the first lower feed motor and the second lower feed motor are disposed at different positions.

6. The sewing machine according to claim 5.

7. In the second direction, a position of the first lower feed motor and a position of at least a part of the second lower feed motor are the same.

7. The sewing machine according to claim 6.

8. the first bottom feed motor is disposed directly below the barrel portion, the second lower feed motor is disposed at a position closer to the cylinder portion than the first lower feed motor; 7. The sewing machine according to claim 6.

9. In the third direction, a position of the first lower feed motor and a position of at least a part of the second lower feed motor are the same. The sewing machine according to any one of claims 5 to 8.

10. a first input shaft coupled to the first lower feed sprocket; a second input shaft coupled to the second lower feed sprocket; a first output shaft coupled to the first bottom feed motor; a second output shaft coupled to the second bottom feed motor; a first transmission mechanism that transmits a rotational force of the first output shaft to the first input shaft; a second transmission mechanism that transmits the rotational force of the second output shaft to the second input shaft, 6. The sewing machine according to claim 5.

11. a first input shaft fixed to the first lower feed sprocket and rotated by a rotational force generated by the first lower feed motor; a second input shaft fixed to the second lower feed sprocket and rotated by a rotational force generated by the second lower feed motor, the second input shaft is cylindrical, The first input shaft is disposed inside the second input shaft.

6. The sewing machine according to claim 5.

12. a bobbin case for holding a bobbin wound with a lower thread and a hook for supplying the lower thread to the upper thread; The shuttle is disposed above the first input shaft. The sewing machine according to claim 11.

13. a first upper feed belt having an annular shape, which is disposed on one side of the sewing position in the first direction and moves to feed the sewing object in the second direction; and a second upper feed belt having an annular shape, which is disposed on the other side of the sewing position and moves to feed the sewing object in the second direction independently of the first upper feed belt, the first upper feed belt and the second upper feed belt are supported by the head portion; 2. The sewing machine according to claim 1.

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