Patent Application
20220290347
This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2021-038707 filed on Mar. 10, 2021, the contents of which are incorporated herein by reference.
The present invention relates to a driving device used in a sewing apparatus that includes an eccentric member for reciprocating a needle up and down and forms stitches on a workpiece.
Conventionally, an instrument panel has been used in a vehicle interior of an automobile. A skin material is sewn on the surface of the instrument panel using a sewing apparatus. A sewing apparatus disclosed in JP 2004-065844 A includes a sewing machine unit and an eccentric mechanism. The sewing machine unit includes a needle for sewing the skin material. The eccentric mechanism converts a rotational driving force from a driving source into an up and down linear motion. The eccentric mechanism transmits the rotational driving force of the driving source to the sewing machine unit. The needle reciprocates up and down by the eccentric mechanism.
The eccentric mechanism includes an eccentric shaft, an eccentric, and a connecting rod. The eccentric shaft is rotatably supported by a base. The eccentric shaft is rotated by the driving force from the driving source. The eccentric shaft is inserted through the eccentric. One end portion of the connecting rod is connected to the eccentric. The other end portion of the connecting rod is connected to a slider. The slider is movable up and down.
The eccentric includes a bearing tube portion and an eccentric tube portion. The bearing tube portion has a circular cross section. A through hole is provided in an axial center of the bearing tube portion. The eccentric tube portion has a circular cross section and is eccentric to the radially outer side of the bearing tube portion. The through hole penetrates from the bearing tube portion to the eccentric tube portion. By inserting the eccentric shaft into the through hole, the eccentric and the eccentric shaft rotate integrally. One end portion of the connecting rod is rotatably supported on an outer peripheral side of the eccentric tube portion.
When the driving source is driven to rotate the eccentric shaft, the eccentric rotates together with the eccentric shaft. With the rotation of the eccentric, the connecting rod connected to the eccentric tube portion reciprocates up and down. Thus, the up and down reciprocating motion of the connecting rod is transmitted to the slider. With the reciprocating motion of the slider, the needle of the sewing machine unit moves up and down via a connecting bar. As the needle moves up and down, the skin material is sewn.
In the sewing apparatus described above, when the eccentric rotates and the connecting rod reciprocates up and down, a load is applied to the eccentric tube portion from the connecting rod. The direction in which the load is applied is orthogonal to the axis of the eccentric shaft. Further, for example, when a workpiece made of a hard resin material is sewn, a load is applied to the sewing machine unit in a direction opposite to a direction in which the needle is inserted into the workpiece, as a reaction force caused by the insertion of the needle into the workpiece. By applying these two types of loads, the eccentric tube portion is pressed radially inward. The eccentric tube portion is bent by the loads. Along with the deformation of the eccentric tube portion, the eccentric tube portion and the outer peripheral surface of the eccentric shaft come into contact with each other and wear occurs. As a result, the durability of the sewing apparatus is reduced due to wear.
An object of the present invention is to solve the above-described problems.
According to an aspect of the present invention, there is provided a driving device that is used in a sewing apparatus for sewing a workpiece, and that drives a needle, the driving device comprising: a driving source configured to be driven to rotate when energized; a shaft connected to the driving source and configured to rotate; and an eccentric member fixed to the shaft and configured to convert a rotational motion of the shaft into an up and down motion of the needle, wherein a cushion member configured to absorb a load applied to the eccentric member in a direction substantially orthogonal to an axial direction of the shaft is disposed between the eccentric member and the shaft.
According to the present invention, the driving device used in the sewing apparatus comprises the eccentric member. As a result, when the driving source is driven to rotate the shaft, the rotational motion of the shaft is converted into the up and down motion of the needle by the eccentric member. At this time, a load in a direction substantially orthogonal to the axial direction of the shaft is applied to the eccentric member. The cushion member is disposed between the eccentric member and the shaft. Thus, the load can be suitably absorbed by the cushion member.
As a result, when the eccentric member is pressed toward the shaft during up and down movement of the needle, it is possible to reliably prevent the eccentric member and the shaft from contacting each other by the cushion member. Therefore, wear of the eccentric member is suppressed, and the durability of the sewing apparatus can be improved.
The above and other objects, features, and advantages of the present invention will become more apparent from the following description when taken in conjunction with the accompanying drawings, in which a preferred embodiment of the present invention is shown by way of illustrative example.
A sewing apparatus 10 sews a skin material 14 on the surface of a workpiece 12 that is an object to be sewn. In the present embodiment, the workpiece 12 is an instrument panel mounted in a vehicle interior of an automobile. The sewing apparatus 10 forms stitches along a sewing line (not shown) on the outer surface of the skin material 14 of the instrument panel serving as the workpiece 12.
As shown in
In the sewing apparatus 10, the sewing mechanism 18 and the moving robot 20 are electrically connected to a control unit (not shown). The sewing mechanism 18 and the moving robot 20 are operated under the control of the control unit.
The sewing mechanism 18 is attached to a tip arm 22 of the moving robot 20. In the sewing apparatus 10 shown in
The casing 16 has a U-shape that is open laterally in a side view seen from the width direction. The casing 16 is hollow. The casing 16 includes a vertical frame portion 24, a lower frame portion 26, and an upper frame portion 28. The vertical frame portion 24 extends in a vertical direction (directions of arrows A1 and A2). The lower frame portion 26 extends in the horizontal direction (directions of arrows B1 and B2) from the lower end of the vertical frame portion 24. The upper frame portion 28 extends in the horizontal direction from the upper end of the vertical frame portion 24. The upper frame portion 28 and the lower frame portion 26 are separated from each other by a predetermined distance in the vertical direction. The upper frame portion 28 and the lower frame portion 26 are parallel to each other.
The casing 16 includes a first protruding portion 30. The first protruding portion 30 is disposed at the distal end of the lower frame portion 26. The first protruding portion 30 protrudes upward (in an arrow A1 direction) from the lower frame portion 26 by a predetermined height. The distal end of the upper frame portion 28 includes a second protruding portion 32. The second protruding portion 32 is disposed to face the first protruding portion 30 in the vertical direction. The second protruding portion 32 protrudes downward (in an arrow A2 direction) from the upper frame portion 28 by a predetermined height.
In the casing 16, the inside of the first protruding portion 30, the inside of the lower frame portion 26, the inside of the vertical frame portion 24, the inside of the upper frame portion 28, and the inside of the second protruding portion 32 communicate with one another.
The sewing mechanism 18 includes a driving source 34, two sewing machine needles (needles) 36a and 36b, a post bed 38, a first power transmission mechanism 40, and a second power transmission mechanism 44. The post bed 38 is disposed so as to face the two sewing machine needles 36a and 36b. The post bed 38 houses two loopers 42a and 42b. The first power transmission mechanism 40 transmits the driving force of the driving source 34 to the sewing machine needles 36a and 36b. The second power transmission mechanism 44 transmits the driving force of the driving source 34 to the two loopers 42a and 42b.
The driving source 34 is, for example, a motor that is driven to rotate when energized. The driving source 34 includes a drive shaft 46 that rotates. The driving source 34 is housed in the vicinity of the distal end in the upper frame portion 28. The drive shaft 46 of the driving source 34 is disposed to face the distal end of the upper frame portion 28. The driving source 34 is disposed such that the drive shaft 46 of the driving source 34 extends horizontally. The distal end of the drive shaft 46 is connected, via a joint 48, to a first driven shaft 56 (described later) of the first power transmission mechanism 40.
The sewing machine needles 36a and 36b extend in the vertical direction (the directions of arrows A1 and A2). The sewing machine needle 36a and the sewing machine needle 36b are disposed parallel to each other while being separated from each other in the horizontal direction (the directions of arrows B1 and B2). Upper ends of the sewing machine needles 36a and 36b are held by a needle holder 50. The sewing machine needles 36a and 36b protrude downward (in the arrow A2 direction) from the lower surface of the needle holder 50. A sewing thread 52a is inserted through a hole (not shown) of the sewing machine needle 36a. A sewing thread 52b is inserted through a hole (not shown) of the sewing machine needle 36b.
The needle holder 50 is disposed below the lower end of the second protruding portion 32. The needle holder 50 is connected to the lower end of a reciprocating shaft 100 (described later) of the first power transmission mechanism 40.
The post bed 38 is housed inside the first protruding portion 30. The two loopers 42a and 42b and a part of the second power transmission mechanism 44 are housed inside the post bed 38.
The loopers 42a and 42b are disposed in the vicinity of the upper end of the first protruding portion 30. The looper 42a and the looper 42b are disposed substantially parallel to each other while being separated from each other in the horizontal direction. The loopers 42a and 42b are rotatably supported within the post bed 38 via a rotating shaft 54. Claw portions (not shown) protruding along the rotation direction are respectively provided on outer peripheral portions of the loopers 42a and 42b. The looper 42a is disposed below the sewing machine needle 36a. The looper 42b is disposed below the sewing machine needle 36b.
The loopers 42a and 42b are aligned with the sewing machine needles 36a and 36b, respectively in the vertical direction. The loopers 42a and 42b rotate with the claw portions taking the lead in the rotation. As a result, tips of the sewing machine needles 36a and 36b are inserted from the outer surface toward the inner surface of the workpiece 12. When the tips of the sewing machine needles 36a and 36b protrude from the inner surface, the sewing threads 52a and 52b inserted through the sewing machine needles 36a and 36b are caught on the claw portions.
The first power transmission mechanism 40 is housed inside the upper frame portion 28 and the second protruding portion 32 in the casing 16. The first power transmission mechanism 40 includes the first driven shaft 56, a second driven shaft (shaft) 60, and an eccentric mechanism 62. The first driven shaft 56 is connected to the drive shaft 46 of the driving source 34. The second driven shaft 60 is disposed in parallel to the first driven shaft 56. The driving force is transmitted from the first driven shaft 56 to the second driven shaft 60 via a first transmission belt 58. The eccentric mechanism 62 is connected to the second driven shaft 60. The eccentric mechanism 62 transmits the driving force from the second driven shaft 60 to the sewing machine needles 36a and 36b.
Each of the first and second driven shafts 56 and 60 is formed from a metallic material. The first and second driven shafts 56 and 60 are housed in the upper frame portion 28 of the casing 16. The first driven shaft 56 is disposed in alignment with the drive shaft 46. The first driven shaft 56 is connected to the drive shaft 46 via the joint 48. A first pulley 64 is mounted to the distal end of the first driven shaft 56.
The second driven shaft 60 is disposed below the first driven shaft 56 (in the arrow A2 direction). The first driven shaft 56 and the second driven shaft 60 are separated from each other by a predetermined distance in the vertical direction and substantially parallel to each other. The second driven shaft 60 is elongated along the axial direction (the directions of arrows B1 and B2). The proximal end of the second driven shaft 60 extends to the vicinity of the proximal end of the upper frame portion 28.
A second pulley 66 is mounted to the distal end of the second driven shaft 60. A third pulley 68 is mounted to the proximal end of the second driven shaft 60. An annular second transmission belt 70 is mounted on the outer periphery of the third pulley 68.
The first transmission belt 58 has an annular shape having a predetermined width. The first transmission belt 58 is wound between the first pulley 64 and the second pulley 66. Thus, after the driving force of the driving source 34 is transmitted to the first driven shaft 56, the driving force is transmitted to the second driven shaft 60 via the first pulley 64, the first transmission belt 58, and the second pulley 66. As a result, the second driven shaft 60 rotates.
As shown in
As shown in
The shaft hole 80 has a constant diameter and extends along the axial direction (the directions of arrows B1 and B2). The second driven shaft 60 can be inserted through the shaft hole 80. The shaft hole 80 penetrates from the first cylindrical portion 82 to the second cylindrical portion 84. The inner diameter of the shaft hole 80 is larger than the outer diameter of the second driven shaft 60. A clearance C (see
The shaft hole 80 includes a first hole portion 86 and a second hole portion 88. The first hole portion 86 is disposed inside the first cylindrical portion 82. The second hole portion 88 is disposed inside the second cylindrical portion 84. One end of the first hole portion 86 opens at one axial end of the eccentric member 72 (an end on the distal end side, the arrow B1 side). One end of the second hole portion 88 opens at the other axial end of the eccentric member 72 (an end on the proximal end side, the arrow B2 side). At this time, at one axial end of the eccentric member 72, the shaft hole 80 opens to the axial center L1 of the first cylindrical portion 82. At the other axial end of the eccentric member 72, the shaft hole 80 opens at a position radially eccentric from an axial center L2 of the second cylindrical portion 84 (see
The second hole portion 88 includes an annular groove 90. The annular groove 90 is disposed in the second hole portion 88 on the proximal end side (the arrow B2 side) of the eccentric member 72. The annular groove 90 is recessed radially outward from the inner peripheral surface of the second hole portion 88. A ring-shaped cushion member 92 is mounted in the annular groove 90.
The cushion member 92 is formed of an incompressible elastic material (incompressible material) such as rubber or silicone. The cushion member 92 has an annular shape. The outer peripheral surface of the cushion member 92 abuts against the inner peripheral surface of the annular groove 90 and is held in the annular groove 90. The inner peripheral surface of the cushion member 92 protrudes further inward in the radial direction than the inner peripheral surface of the second hole portion 88. The inner peripheral surface of the cushion member 92 is slidable on the outer peripheral surface of the second driven shaft 60.
The cushion member 92 is not limited to being mounted to the eccentric member 72. The cushion member 92 may be mounted to the outer peripheral surface of the second driven shaft 60. The cushion member 92 is not limited to being a single member and having an annular shape. For example, a plurality of the cushion members 92 may be scattered along the inner peripheral surface of the second hole portion 88.
The first cylindrical portion 82 includes a screw hole 94. As shown in
After the second driven shaft 60 is inserted into the shaft hole 80 of the eccentric member 72, the fixing screw 78 is screwed. In accordance with the screwing of the fixing screw 78, the fixing screw 78 is moved radially inward, that is, toward the second driven shaft 60. As a result, the tip of the fixing screw 78 comes into contact with the outer peripheral surface of the second driven shaft 60. Therefore, the eccentric member 72 and the second driven shaft 60 do not rotate relative to each other, and the eccentric member 72 and the second driven shaft 60 are fixed relative to each other. At this time, the clearance C is provided between the shaft hole 80 of the eccentric member 72 and the second driven shaft 60. That is, the fixing screw 78 is a fixing member that fixes the second driven shaft 60 and the eccentric member 72 without causing relative rotation therebetween.
As shown in
The first annular portion 96 is rotatably connected to the second cylindrical portion 84 of the eccentric member 72. The second annular portion 98 is rotatably connected to the transmission shaft 76. The connecting rod 74 connects the second driven shaft 60 and the transmission shaft 76. Thus, the connecting rod 74 can transmit the driving force, which is transmitted to the second driven shaft 60, to the transmission shaft 76.
As shown in
The second power transmission mechanism 44 is housed inside the lower frame portion 26 and the first protruding portion 30 in the casing 16. The second power transmission mechanism 44 includes a third driven shaft 102. The third driven shaft 102 extends along the lower frame portion 26. The third driven shaft 102 is separated from the second driven shaft 60 in the vertical direction and is substantially parallel to the second driven shaft 60.
A fourth pulley 104 is connected to the proximal end of the third driven shaft 102. A fifth pulley 106 is connected to the distal end of the third driven shaft 102. The second transmission belt 70 is wound between the fourth pulley 104 and the third pulley 68. Thus, the driving force of the driving source 34 is transmitted to the second driven shaft 60 of the first power transmission mechanism 40, and is then transmitted to the third driven shaft 102 via the third pulley 68, the second transmission belt 70, and the fourth pulley 104. As a result, the third driven shaft 102 rotates by the driving force of the driving source 34.
The second power transmission mechanism 44 includes a fourth driven shaft 108, a third transmission belt 112, a first gear 114, and a second gear 116. The fourth driven shaft 108 is disposed substantially parallel to the third driven shaft 102 inside the first protruding portion 30. A sixth pulley 110 is connected to the proximal end of the fourth driven shaft 108. The third transmission belt 112 is wound around the fifth pulley 106 and the sixth pulley 110. The first gear 114 is fitted onto the fourth driven shaft 108. The second gear 116 and the first gear 114 mesh with each other.
The fourth driven shaft 108 is separated upward (in the arrow A1 direction) from the third driven shaft 102 by a predetermined distance. The fourth driven shaft 108 is substantially parallel to the third driven shaft 102. The fourth driven shaft 108 is rotatably supported in the first protruding portion 30.
The outer peripheral surface of the first gear 114 has a plurality of first tooth portions (not shown) along the outer peripheral surface. The first gear 114 is disposed at the axial center of the fourth driven shaft 108. The first gear 114 is disposed adjacent to the sixth pulley 110. The first gear 114 rotates together with the fourth driven shaft 108.
The second gear 116 is connected to the axial center of the rotating shaft 54. The rotating shaft 54 is disposed above the fourth driven shaft 108. The rotating shaft 54 and the fourth driven shaft 108 are separated from each other in the vertical direction and are substantially parallel to each other. The outer peripheral surface of the second gear 116 has a plurality of second tooth portions (not shown) along the outer peripheral surface. The second tooth portions of the second gear 116 and the first tooth portions of the first gear 114 mesh with each other. As a result, the first gear 114 and the second gear 116 rotate together. The two loopers 42a and 42b are mounted to both ends of the rotating shaft 54 in the width direction so as to sandwich the second gear 116. The rotating shaft 54 rotates together with the second gear 116, whereby the two loopers 42a and 42b rotate.
Next, the operation and effects of the sewing apparatus 10 will be described.
First, the moving robot 20 is operated under the control of a control unit (not shown). The tip arm 22 of the moving robot 20 is brought close to the workpiece 12. Thus, the post bed 38 (loopers 42a and 42b) and the sewing machine needles 36a and 36b are disposed at positions sandwiching the sewing line along which sewing is performed in the workpiece 12. That is, the two loopers 42a and 42b and the two sewing machine needles 36a and 36b are respectively disposed above and below the workpiece 12 (in the directions of arrows A1 and A2). Incidentally, the sewing threads 52a and 52b are passed through the holes (not shown) of the sewing machine needles 36a and 36b, respectively, in advance.
Next, the driving source 34 is driven based on a control signal from the control unit (not shown). The drive shaft 46 of the driving source 34 rotates. The first driven shaft 56 and the first pulley 64 rotate together with the drive shaft 46. As the first pulley 64 rotates, the first transmission belt 58 revolves. As a result, the second pulley 66 rotates via the first transmission belt 58, and the second driven shaft 60 is driven to rotate together with the second pulley 66.
The eccentric member 72 rotates with the rotation of the second driven shaft 60. The first cylindrical portion 82 of the eccentric member 72 is disposed coaxially with the second driven shaft 60. Therefore, the eccentric member 72 rotates about the axial center L1 of the first cylindrical portion 82. As shown in
At this time, as shown in
Specifically, when the load F is applied from the first annular portion 96 toward the second cylindrical portion 84, the distance by which the cushion member 92 pressed by the load F is compressed in the radial direction is smaller than the radial length of the clearance C between the inner peripheral surface of the first annular portion 96 (the second hole portion 88) and the outer peripheral surface of the second driven shaft 60. Therefore, even when the cushion member 92 is compressed in the radial direction, the predetermined width of the clearance C is maintained. In other words, when the cushion member 92 is compressed in the radial direction, the width of the clearance C does not become 0. Thus, when the load F is applied from the first annular portion 96 toward the second cylindrical portion 84, contact between the second cylindrical portion 84 and the second driven shaft 60 is prevented by the cushion member 92.
As shown in
The third pulley 68 rotates together with the second driven shaft 60. With the rotation of the third pulley 68, the second transmission belt 70 revolves and the fourth pulley 104 rotates. With the rotation of the fourth pulley 104, the third driven shaft 102 is driven to rotate. When the fifth pulley 106 rotates together with the third driven shaft 102, the third transmission belt 112 revolves.
As the third transmission belt 112 revolves, the sixth pulley 110, the fourth driven shaft 108, and the first gear 114 are driven to rotate. As a result, the second gear 116 meshing with the first tooth portions of the first gear 114 is driven to rotate. With the rotation of the second gear 116, the two loopers 42a and 42b fixed to the rotating shaft 54 integrally rotate. Note that the two loopers 42a and 42b rotate in synchronization. While the two sewing machine needles 36a and 36b reciprocate up and down once, the two loopers 42a and 42b rotate once.
The sewing machine needles 36a and 36b are inserted into the workpiece 12 from the upper surface of the workpiece 12 by advancing along a forward path extending downward from the top dead center located at the uppermost position. When the sewing machine needles 36a and 36b reach the bottom dead center located at the lowermost position, the tips of the sewing machine needles 36a and 36b protrude from the lower surface of the workpiece 12. The tips of the sewing machine needles 36a and 36b protrude from the lower surface of the workpiece 12 and enter the inside of the post bed 38. As a result, the sewing threads 52a and 52b inserted through the sewing machine needles 36a and 36b penetrate the workpiece 12. Thereafter, the sewing machine needles 36a and 36b advance along a return path extending from the bottom dead center toward the top dead center. While the sewing machine needles 36a and 36b are lifted, the sewing machine needles 36a and 36b are removed from the post bed 38 and the workpiece 12.
When the sewing machine needles 36a and 36b are caused to penetrate the instrument panel serving as the workpiece 12 formed of a hard resin material, a reaction force (load) directed upward is applied to the sewing machine needles 36a and 36b from the workpiece 12. This reaction force is transmitted from the sewing machine needles 36a and 36b to the connecting rod 74 via the reciprocating shaft 100 and the transmission shaft 76. As a result, the connecting rod 74 is biased upward (in the arrow A1 direction) by the reaction force. Here, the annular cushion member 92 made of an incompressible material is mounted inside the second hole portion 88 of the second cylindrical portion 84 of the eccentric member 72. Therefore, when a load is applied from the first annular portion 96 of the connecting rod 74 to the second cylindrical portion 84 of the eccentric member 72, contact between the second cylindrical portion 84 and the second driven shaft 60 is reliably prevented.
When the sewing threads 52a and 52b pass through the workpiece 12, the claw portions (not shown) of the loopers 42a and 42b reach the top dead center. Then, when the loopers 42a and 42b rotate in a state in which the sewing threads 52a and 52b are caught on the claw portions, the sewing threads 52a, 52b is pulled downward. Thus, loop portions are formed in the vicinity of the lower surface of the workpiece 12 by the sewing threads 52a and 52b.
The sewing threads 52a and 52b pulled when the sewing machine needles 36a and 36b are inserted (when the loopers 42a and 42b rotate) next time are inserted into the loop portions, respectively. The moving robot 20 operates as appropriate under the control of the control unit. With the operation of the moving robot 20, the sewing mechanism 18 moves in parallel along the workpiece 12. In the sewing mechanism 18, the sewing machine needles 36a and 36b reciprocate, and the loopers 42a and 42b repeatedly rotate. As a result, the plurality of loop portions are joined to each other so that sewing is performed on the lower surface of the workpiece 12.
On the upper surface of the workpiece 12, stitches that are joined linearly are formed on the sewing line. As a result, the skin material 14 is sewn on the upper surface of the workpiece 12.
In the present embodiment, the sewing apparatus 10 includes the sewing mechanism 18 for driving the two sewing machine needles 36a and 36b. The sewing mechanism 18 includes the driving source 34, the second driven shaft 60, and the eccentric member 72. The driving source 34 is driven to rotate when energized. The second driven shaft 60 is connected to the drive shaft 46 of the driving source 34 via the first driven shaft 56 and rotates therewith. The eccentric member 72 is fixed to the second driven shaft 60. The eccentric member 72 converts the rotational motion of the second driven shaft 60 into the up and down motion of the sewing machine needles 36a and 36b. In the eccentric member 72, the cushion member 92 is disposed between the second driven shaft 60 and the second hole portion 88 into which the second driven shaft 60 is inserted.
The driving source 34 is driven to rotate the second driven shaft 60 and the eccentric member 72. As the eccentric member 72 rotates, the connecting rod 74 holding the sewing machine needles 36a and 36b reciprocates up and down. At this time, the load F may be applied to the eccentric member 72, and the second cylindrical portion 84 may be pressed toward the second driven shaft 60 and deform. Even in the case, the cushion member 92 can prevent contact between the shaft hole 80 of the eccentric member 72 and the outer peripheral surface of the second driven shaft 60. As a result, wear (fretting) of the second driven shaft 60 due to contact between the eccentric member 72 and the second driven shaft 60 is suppressed. This makes it possible to improve the durability of the eccentric member 72 and the second driven shaft 60. By improving the durability of the eccentric member 72 and the second driven shaft 60, it is possible to reduce the frequency of parts replacement and maintenance man-hours for the eccentric member 72 and the second driven shaft 60.
The eccentric member 72 includes the first cylindrical portion 82 and the second cylindrical portion 84. The first cylindrical portion 82 is disposed coaxially with the axial center L1 of the second driven shaft 60. The second cylindrical portion 84 is disposed closer to the other side in the axial direction of the second driven shaft 60 (the arrow B2 side) than the first cylindrical portion 82 is. The axial center of the second cylindrical portion 84 is eccentric in the radial direction from the axial center L1 of the second driven shaft 60. The first annular portion 96 of the connecting rod 74 is connected to the second cylindrical portion 84. The cushion member 92 is mounted to the second cylindrical portion 84.
When the connecting rod 74 reciprocates up and down to reciprocate the sewing machine needles 36a and 36b up and down, the load F may be applied from the first annular portion 96 to the second cylindrical portion 84. At this time, contact between the second cylindrical portion 84 and the second driven shaft 60 is suitably prevented by the cushion member 92, and wear of the second cylindrical portion 84 and the second driven shaft 60 can be avoided.
The second driven shaft 60 is inserted through the first cylindrical portion 82 and fixed to the first cylindrical portion 82 by the fixing screw 78 in a direction orthogonal to the axial direction of the second driven shaft 60. Therefore, the eccentric member 72 and the second driven shaft 60 can be more firmly fixed by the fixing screw 78. As the eccentric member 72 and the second driven shaft 60 are fixed to each other, contact between the eccentric member 72 and the second driven shaft 60 is further suppressed, and wear can be reduced.
The annular cushion member 92 is mounted on the inner peripheral surface of the second hole portion 88 inside the second cylindrical portion 84. As a result, contact between the inner peripheral surface of the second hole portion 88 and the second driven shaft 60 inserted through the second hole portion 88 can be reliably prevented by the cushion member 92 over the entire circumferences of the second hole portion 88 and the second driven shaft 60.
The cushion member 92 is formed from an incompressible elastic material such as rubber or silicone. Thus, when the load F is applied from the first annular portion 96 of the connecting rod 74 to the second cylindrical portion 84 of the eccentric member 72, the load F can be suitably absorbed by the cushion member 92. For this reason, the clearance C between the second cylindrical portion 84 and the second driven shaft 60 can be constantly maintained by the cushion member 92. As a result, contact between the second cylindrical portion 84 and the second driven shaft 60 can be prevented.
The above embodiment can be summarized as follows.
The above embodiment relates to a driving device that is used in a sewing apparatus (10) for sewing a workpiece, and that drives a needle (36a, 36b), the driving device comprising: a driving source (34) configured to be driven to rotate when energized; a shaft (60) connected to the driving source and configured to rotate; and an eccentric member (72) fixed to the shaft and configured to convert a rotational motion of the shaft into an up and down motion of the needle, wherein a cushion member (92) configured to absorb a load applied to the eccentric member in a direction substantially orthogonal to an axial direction of the shaft is disposed between the eccentric member and the shaft.
According to this feature, when the needle reciprocates up and down as the shaft and the eccentric member rotate, the load applied to the eccentric member can be absorbed by the cushion member. As a result, contact between the eccentric member and the shaft due to application of the load can be prevented by the cushion member. Therefore, the durability of the eccentric member and the shaft can be improved.
The eccentric member includes: a first cylindrical portion (82) formed coaxially with an axial center of the shaft; and a second cylindrical portion (84) disposed on one side of the first cylindrical portion in the axial direction of the shaft, and radially eccentric from the axial center of the shaft, wherein the cushion member is disposed in the second cylindrical portion.
According to this feature, when the needle reciprocates up and down and a load is applied to the second cylindrical portion as the shaft and the eccentric member rotate, contact between the second cylindrical portion and the shaft is prevented by the cushion member. Therefore, wear of the second cylindrical portion and the shaft can be avoided.
The eccentric member and the shaft are fixed to each other by a fixing member (78) provided in the first cylindrical portion. According to this feature, the eccentric member and the shaft can be firmly fixed by the fixing member. As a result, with the fixation of the eccentric member and the shaft, contact between the eccentric member and the shaft is further suppressed, and wear of the eccentric member and the shaft can be reduced.
Since the cushion member has an annular shape, contact between the eccentric member and the shaft can be reliably prevented over the entire circumference of the shaft.
Since the cushion member is formed of an incompressible material, when a load is applied to the eccentric member, the load can be suitably absorbed by the cushion member. As a result, the clearance between the eccentric member and the shaft can be constantly maintained by the cushion member to prevent contact therebetween.
Note that the present invention is not limited to the embodiment described above, and various configurations can be adopted therein without departing from the gist of the present invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2021-038707 | Mar 2021 | JP | national |
