JP2008284401A - Motion converting mechanism - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motion converting mechanism, reducing noise and abrasion, and simplifying design and manufacture. <P>SOLUTION: This motion converting mechanism 40 includes: a rotary plate 41 rotating with a rotating shaft 47; a rocking link 51 rocking when the rotary plate 41 is rotated, wherein one surface and the other surface of the rotary plate 41 are formed with an outer peripheral cam face 43 and an inner peripheral cam face 45 in which the central trajectories p of cam followers 53, 55 are the same to be inversion symmetrical about the rotary plate 41. The rocking link 51 includes an outer peripheral cam lever 52, on which a roller-like cam followers 53 rolling on the outer peripheral cam face 43 is rotatably mounted, and an inner peripheral cam lever 54 on which a roller-like cam follower 55 rolling on the inner peripheral cam face 45 is rotatably mounted, wherein both levers 52, 54 are connected to each other so that axes c of both roller-like cam followers 53, 55 coincide. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a motion conversion mechanism for extracting a linear reciprocating motion from a rotational motion.

  Usually, the sewing machine drives a reciprocating action unit such as a needle bar, a cloth presser bar, a balance, or a lower thread shuttle by various driving mechanisms. Among these various drive mechanisms, there is one provided with a motion conversion mechanism 185 as in Conventional Example 1 shown in FIG. 7A (Patent Document 1). The motion conversion mechanism 185 includes a cam 186 that is rotationally driven, and a lever 187 that includes a cam follower 188 that contacts the cam 186. A spring 189 that presses the cam follower 188 against the cam surface 186a is attached to the lever 187 so that the lever 187 can follow the movement of the cam 186.

  However, when the cam follower 188 is pressed against the cam surface 186a by the pressing force of the spring 189 as described above, an extra resistance is applied to the cam 186 by the pressing force.

  For this reason, some types of motion conversion mechanisms include positive cams that cause the levers to follow the movement of the cams without being pressed by a spring or the like. Among them, there are a motion conversion mechanism 190 of Conventional Example 2 shown in FIG. 7B, a motion conversion mechanism 194 of Conventional Example 3 shown in FIG.

  The motion conversion mechanism 190 of the conventional example 2 includes a plate groove cam 191 having a groove 192 formed in a side surface, and cam followers 193 are formed on both side walls of the groove 192 in the groove 192. It is a mechanism that rolls and slides along one of 192a and 192b alternately.

On the other hand, the motion conversion mechanism 194 of the conventional example 3 includes a conjugate cam 195 having a structure in which two cams 196 and 197 having different cross-sectional shapes are arranged in the axial direction and fixed so as not to move relative to each other. One of the two cam followers 199 attached to the swing link 198 is in contact with the cam surface 196a of 196, and the other 199b of the cam follower 199 is in contact with the cam surface 197a of the other cam 197. ing. The two cam followers 199a and 199b are alternately pressed against the common benefit cam 195 so that the swing link 198 follows the movement of the common benefit cam 195.
Japanese Patent No. 2752482 Japanese Patent Laid-Open No. 9-192371 Japanese Patent Laid-Open No. 2004-1000073

  However, in the motion conversion mechanism 190 of the second conventional example, when the cam follower 193 comes into contact with both the cam surfaces 192a and 192b, the cam follower 193 cannot rotate. This will cause backlash and noise. Further, when the cam surfaces 192a and 192b on which the cam follower 193 rolls are changed from one to the other, the rotation direction of the cam follower 193 is changed, and there is a slip pair. For this reason, wear proceeds locally at the portion where the rotation direction changes.

  Further, in the conjugate cam 195 of the conventional example 3, problems such as wear and backlash in the conventional example 2 are improved. However, since two cams 196 and 197 having different cross-sectional shapes are used, and the cam follower 199a. Since the pitch between 199b must be adjusted with high precision, both the common cam 195 and the swing link 198 are highly difficult to design, manufacture, and maintain.

  Accordingly, it is an object of the present invention to provide a motion conversion mechanism in which a cam follower does not give an excessive pressing force to a cam surface, noise and wear are small, and design and manufacture are simple.

  In order to achieve the above object, the motion conversion mechanism of the present invention has an outer peripheral cam surface in which the central track of the cam follower is the same in a reverse symmetry with respect to the rotary plate on one side and the other side of the rotary plate rotating together with the rotary shaft And a lever having a roller cam follower that rotates on the outer cam surface and a roller cam roller follower that rotates on the inner cam surface. Are provided so as to take out reciprocating motion from the swing of the swing link. However, here, the outer peripheral cam surface refers to a cam surface composed of an outer peripheral surface, and the inner peripheral cam surface refers to a cam surface composed of an inner peripheral surface.

The present invention relating to the motion conversion mechanism is general-purpose and can be incorporated into, for example, a drive mechanism that drives a reciprocating part of a sewing machine, and can be used for various devices other than the sewing machine (for example, various looms, various machine tools, etc.). It can also be incorporated into various drive mechanisms that drive the reciprocating operation part.
The reciprocating part of the sewing machine is not particularly limited, and examples thereof include a needle bar, a cloth presser bar, a balance, and a lower thread shuttle. Further, the reciprocating motion is not particularly limited, and examples thereof include a swinging motion and a linear reciprocating motion.

  According to the present invention, since there is no spring or the like as in Conventional Example 1 in the motion conversion mechanism, no extra pressing force is applied to the cam surface.

  In addition, since the roller-shaped cam follower that rolls on the outer peripheral cam surface and the roller-shaped cam follower that rolls on the inner peripheral cam surface are different from each other, each cam follower can be brought into contact with both cam surfaces at the same time. The rotation direction can be made constant. Therefore, compared with the prior art 2, backlash and noise can be reduced, and wear can be reduced.

  Further, since the outer peripheral cam surface and the inner peripheral cam surface are inversion symmetric, the design of both cam surfaces only needs to reverse the machining data, and the cam surface can be easily designed and manufactured. Further, since the shaft cores of both roller-shaped cam followers coincide with each other, it is not necessary to adjust the pitch between the two cam followers with high accuracy as in the conjugate cam of the conventional example 3, and the design and manufacture of the swing link is easy.

  The motion conversion mechanism 40 includes a rotating plate 41 that rotates together with the rotating shaft 47, a swinging link 51 that swings when the rotating plate 41 rotates, and a reciprocating link 71 that extracts reciprocating motion from the swinging. Yes. An outer peripheral cam surface 43 and an inner peripheral cam surface 45 are formed on one surface and the other surface of the rotating plate 41 so that the center orbits p of the cam followers 53 and 55 are the same in reverse symmetry with respect to the rotating plate 41. . In addition, the swing link 51 is configured so that the outer cam lever 52 that rotatably attaches the roller-shaped cam follower 53 that rolls on the outer cam surface 43 and the roller-shaped cam follower 55 that rolls on the inner cam surface 45 can rotate. The inner cam levers 54 are attached to each other, and the two levers 52 and 54 are connected so that the shaft cores c of the two roller-shaped cam followers 53 and 55 are coincident with each other.

  The multi-head sewing machine 9 shown in FIGS. 1 to 5 incorporating the motion conversion mechanism 40 of the first embodiment includes a bed 20 that supplies a lower thread, an upper thread supply unit (not shown) that supplies an upper thread, and sewing. The sewing machine head 10 is configured to sew an object with an upper thread and a lower thread. The sewing head 10, the bed 20 and the upper thread supply unit (not shown) are attached to a sewing machine frame (not shown) of the multi-head sewing machine 9.

  A plurality of sewing heads 10 are provided side by side, and each sewing head 10 has a needle bar 11 for sewing, and a cloth presser bar 13 for pressing an object to be sewn (not shown). Is attached. The needle bar 11 can be raised and lowered by a needle bar drive mechanism (not shown), and an embroidery needle 12 for embroidery is attached to the lower end of the needle bar 11. The presser foot 13 has a presser foot 14 attached to its lower end.

  The bed 20 is provided below the sewing head 10, and a needle plate 21 through which the embroidery needle 12 descends and penetrates, a plurality of lower thread shuttles 22 serving as lower thread supply sources, and lower thread shuttles. 22 includes a plurality of shuttle guides 23 for guiding the drive direction of 22 and a shuttle drive mechanism 29 for simultaneously driving all the lower thread shuttles 22.

  The shuttle drive mechanism 29 is a mechanism for causing the bobbin thread shuttle 22 to reciprocate linearly, and converts the drive motor 30 serving as a power source and the rotational movement of the drive motor 30 into linear reciprocating motion. And a motion conversion mechanism 40 for transmitting to the lower thread shuttle 22.

  The drive motor 30 is a power source that rotationally drives the rotary plate 41 of the motion conversion mechanism 40, and includes a drive shaft 31 that is rotationally driven, and transmits power to the rotary plate 41 at the tip of the drive shaft 31. A drive gear 38 is attached.

  The motion conversion mechanism 40 is a mechanism that converts the rotational motion supplied by the driving motor 30 into a swing motion, and then converts the swing motion into a linear reciprocating motion. A rotating plate 41 to be driven, a swinging link 51 to which the rotating motion of the rotating plate 41 is transmitted and oscillated, a horizontal shaft 60 for transmitting the oscillating motion of the oscillating link 51 in the direction in which the sewing machine head 10 is provided, The transmission link 61 transmits the swinging motion of the shaft 60 to the next reciprocating link 71, and the reciprocating link 71 extracts the linear reciprocating motion from the transmitted swinging motion.

  The rotating plate 41 is a plate that is rotated by the driving motor 30 together with the rotating shaft 47, and a transmission gear 48 that meshes with the driving gear 38 is attached to the rotating shaft 47 so as not to be relatively movable. An outer peripheral cam portion 42 having an outer peripheral cam surface 43 with which one roller-shaped cam follower 53 of the swing link 51 abuts from the outer peripheral side on one surface side and the other surface side of the rotating plate 41, and the swing link An inner circumferential cam portion 44 having an inner circumferential cam surface 45 with which the other roller-shaped cam follower 55 of 51 abuts from the inner circumferential side is formed to protrude. The outer peripheral cam surface 43 and the inner peripheral cam surface 45 have a shape in which the center orbits p of both roller-shaped cam followers 53 and 55 are the same with respect to the rotating plate 41 in reverse symmetry. The rotating plate 41 includes an attaching portion 46 that is attached to the rotating shaft 47 so as not to be relatively movable. The attaching portion 46 is formed so as to further protrude from the outer peripheral cam portion 42.

  The swing link 51 is a link for transmitting the swing motion to the horizontal shaft 60 after converting the rotational motion of the rotating plate 41 to the swing motion, and is attached to the sewing machine frame (not shown) so as to be rotatable. A rotating shaft 57, and an outer peripheral cam lever 52, one end of which is attached to the rotating shaft 57 so as not to be relatively movable, and a roller-like cam follower 53 that rolls on the outer peripheral cam surface 43 is rotatably attached to the other end. An inner peripheral cam lever 54 having one end attached to the rotary shaft 57 so as not to move relative to the other end and a roller-shaped cam follower 55 that rolls on the inner peripheral cam surface 45 rotatably attached to the other end; The swing lever 56 is attached to the horizontal shaft 60 so as not to be relatively movable, and the other end is rotatably attached to the horizontal shaft 60. The outer peripheral cam lever 52 and the inner peripheral cam lever 54 are fixed to the rotating shaft 57 so that the shaft cores c of these roller-shaped cam followers 53 and 55 are aligned. Specifically, the levers 52 and 54 are fixed to the rotating shaft 57 by fixing the fixing portions 52 a and 54 a provided at one end of the levers 52 and 54 to the rotating shaft 57. The protruding length from the rotating shaft 57 can be adjusted by shifting the fixing position by the fixing portions 52a and 54a. In addition, since all the constituent elements of the swing link 51 are attached to the rotating shaft 57 so as not to move relative to each other as described above, the entire rotating shaft 57 is integrally formed when an external force is applied. Will rotate around the center.

  The horizontal shaft 60 is a shaft for transmitting the swinging motion of the swing link 51 in the direction in which the sewing head 10 is provided. In addition to the swing link 51 being connected, a plurality of transmission links 61 are connected. Has been.

  The transmission link 61 is a link that transmits the swinging motion of the horizontal shaft 60 to the reciprocating link 71, and a rotation shaft 67 that is rotatably attached to a sewing machine frame (not shown), and the rotation shaft 67. A first transmission lever 62 having one end attached so as not to be relatively movable and the other end rotatably attached to the horizontal shaft 60, and one end attached to the rotary shaft 67 so as not to be relatively movable, and the other end reciprocating. The second transmission lever 63 is rotatably attached to the conversion lever 72 of the link 71. Since all the components of the transmission link 61 are pivotally attached to the rotation shaft 67 so as not to move relative to each other as described above, the entire transmission link 61 is integrally attached to the rotation shaft 67 when an external force is applied. It will turn to the center.

  The reciprocating link 71 is a link for taking out the linear reciprocating motion from the swinging motion transmitted by the transmission link 61 and causing the lower thread shuttle 22 to perform the linear reciprocating motion, and the end of the second transmission lever 63 rotates at one end. The conversion lever 72 is movably attached, the slide plate 73 is rotatably attached to the other end of the conversion lever 72, and the LM guide 75 guides the slide direction of the slide plate 73. The slide plate 73 extends in the direction in which the sewing head 10 is provided, and on its upper surface, two shuttle drive pins 74 for simultaneously driving a plurality of lower thread shuttles 22 are provided for each lower thread shuttle 22. It is worn. Specifically, one shuttle drive pin 74 is attached to each side in the drive direction of each lower thread shuttle 22.

The state when the multi-head sewing machine 9 shown above operates as shown by the arrows in FIGS. 1 and 2 and sews a workpiece (not shown) will be described below.
(1) First, the drive motor 30 is operated, and the rotational motion is transmitted in the order of the drive shaft 31 → the drive gear 38 → the transmission gear 48 → the rotary shaft 47, and the rotary plate 41 is rotationally driven.
(2) Next, by this rotational drive, the roller-shaped cam follower 53 of the outer peripheral cam lever 52 is alternately pressed against the outer peripheral cam surface 43 and the roller-shaped cam follower 55 of the inner peripheral cam lever 54 is alternately pressed against the inner peripheral cam surface 45 in order. The moving link 51 swings.
(3) Next, the swing of the swing link 51 is transmitted to the horizontal shaft 60, and the horizontal shaft 60 swings.
(4) Next, the swing of the horizontal shaft 60 is transmitted to the transmission link 61, and the transmission link 61 swings.
(5) Next, the swinging motion of the transmission link 61 is transmitted to the reciprocating link 71, where the swinging motion is converted into a linear reciprocating motion in the direction guided by the LM guide 75, and the slide plate 73 is Make a linear reciprocating motion. At this time, the two shuttle drive pins 74 attached to the slide plate 73 alternately press the lower thread shuttle 22 from both sides, so that the lower thread shuttle 22 performs linear reciprocating motion. To do. At this time, also on the sewing head 10 side, the needle bar 11 linearly reciprocates at the same cycle as the lower thread shuttle 22, and the upper thread loop formed near the tip of the embroidery needle 12 is moved to the lower thread shuttle. When 22 passes through, an article to be sewn (not shown) is sewn with an upper thread and a lower thread.

  According to the first embodiment, since the roller-shaped cam follower 53 that rolls on the outer peripheral cam surface 43 and the roller-shaped cam follower 55 that rolls on the inner peripheral cam surface 45 exist, when the rotating plate 41 rotates. The at least one of the cam followers 53 and 55 is pressed against the outer peripheral cam surface 43 or the inner peripheral cam surface 45. Therefore, the swing link 51 can follow the movement of the rotating plate 41 without the spring 189 and the like as in the conventional example 1.

  Further, since the roller-shaped cam follower 53 that rolls on the outer peripheral cam surface 43 and the roller-shaped cam follower 55 that rolls on the inner peripheral cam surface 45 are different from each other, the cam followers 53 and 55 are simultaneously attached to both the cam surfaces 43 and 45. The cam followers 53 and 55 can be rotated in a constant direction. Therefore, the backlash and noise can be reduced as compared with the conventional example 2, and the wear can be reduced. Furthermore, the realization of high speed is also expected.

  Also, a method of applying a pressure between the cam surfaces 43 and 45 and the cam followers 53 and 55 and simultaneously bringing the cam followers 53 and 55 into contact with the cam surfaces 43 and 45 as described above. However, as in the case of a conventional conjugate cam, the distance between the cam and the swing link is not reduced, but one of the outer cam lever 52 and the inner cam lever 54 is loosened and the other cam is fixed. It is easy because it only needs to be fixed again so that it sticks to the lever.

  In addition, since the outer peripheral cam surface 43 and the inner peripheral cam surface 45 are symmetrical with each other, the design of both the cam surfaces 43 and 45 only needs to reverse the machining data, and the cam surface can be easily designed and manufactured. Further, since the shaft cores c of both the roller-shaped cam followers 53 and 55 coincide with each other, it is not necessary to adjust the pitch between the two cam followers with high accuracy as in the conjugate cam 195 of the conventional example 3, and the swing link 51 is designed and manufactured. Is also easy. Furthermore, since the outer peripheral cam lever 52 and the inner peripheral cam lever 54 may have a common structure, the design and manufacture are also easy in this respect.

  The sewing machine 80 shown in FIG. 6 incorporating the motion conversion mechanism 84 of the second embodiment includes a needle bar 81 for sewing, a balance 82 for bending the upper thread, and the needle bar 81 and the balance 82. And a drive mechanism 83 that is driven simultaneously. The drive mechanism 83 includes a drive motor (not shown) as a power source, and a motion conversion mechanism 84 that converts the rotational motion of the drive motor into a swing motion or a linear reciprocating motion. . The motion conversion mechanism 84 includes a needle bar rotary plate 85 for driving the needle bar 81, a needle bar swing link 90 connected to the needle bar rotary plate 85, and the needle bar swing link. 90, a needle bar reciprocating link 95, a balance rotary plate (not shown) for driving the balance 82, and a balance swing connected to the balance rotary plate. Link 100. The needle bar rotating plate 85 and the balance rotating plate (not shown) are attached to the same rotating shaft 88 so as not to move relative to each other, and both are rotationally driven together with the rotating shaft 88.

  The needle bar rotating plate 85 is a member that transmits the rotational movement of the driving motor transmitted through the rotating shaft 88 to the needle bar rocking link 90, and is substantially the same as the rotating plate 41 of the first embodiment. A surface 86 and an inner peripheral cam surface 87 are provided.

  The needle bar swinging link 90 is a link for transmitting the swinging motion to the needle bar reciprocating link 95 after converting the rotational motion of the needle bar rotating plate 85 into the swinging motion. In substantially the same manner as the swing link 51, it includes a rotation shaft 94, an outer peripheral cam lever 91, an inner peripheral cam lever 92, and a swing lever 93. The roller-shaped cam followers 91a and 92a are attached to the tips of the outer peripheral cam lever 91 and the inner peripheral cam lever 92, respectively. However, the swinging lever 93 is different from the swinging link 51 of the first embodiment in that a needle bar reciprocating link 95 is rotatably attached to the tip of the swinging lever 93. In FIG. 6, the inner peripheral cam lever 92 and its roller-shaped cam follower 92a overlap the outer peripheral cam lever 91 and its roller-shaped cam follower 91a.

  The needle bar reciprocating link 95 is a mechanism for converting the swinging motion of the needle bar swinging link 90 into a linear reciprocating motion and then transmitting the linear reciprocating motion to the needle bar 81 to drive the needle bar 81 up and down. A conversion lever 96 having an end of a swing lever 93 rotatably attached to one end, a slide member 97 having the other end of the conversion lever 96 rotatably attached, It comprises a slide shaft 98 for guiding the slide direction.

  The balance rotating plate (not shown) is a member that transmits the rotational movement of the driving motor transmitted through the rotating shaft 88 to the swing link 100 for the balance, and is substantially the same as the rotating plate 41 of the first embodiment. A cam surface and an inner peripheral cam surface are provided. Therefore, the balance rotating plate has substantially the same configuration and function as the needle bar rotating plate 85, but its cam profile is different from the needle bar rotating plate 85. In FIG. 6, the balance rotating plate is hidden behind the needle bar rotating plate 85.

  The balance swinging link 100 is a link for converting the rotational motion of the balance swinging rotary plate into a swinging motion and then transmitting the swinging motion to the balance 82 so that the balance 82 swings. Substantially similar to the swing link 51, it includes a rotation shaft 104, an outer peripheral cam lever 101, an inner peripheral cam lever 102, and a swing lever 103. Then, roller-shaped cam followers are attached to the tips of the outer peripheral cam lever 101 and the inner peripheral cam lever 102, respectively. However, the swinging lever 103 is different from the swinging link 51 of the first embodiment in that a balance 82 is rotatably attached to the end of the swinging lever 103 instead of the horizontal shaft 60. In FIG. 6, the inner peripheral cam lever 102 overlaps the outer peripheral cam lever 101.

  According to the second embodiment, the same effect as that of the first embodiment can be exerted on the drive mechanism of the needle bar and the balance.

  It should be noted that the present invention is not limited to the above-described embodiment, and can be appropriately modified and embodied without departing from the spirit of the invention. For example, a drive mechanism incorporating the same embodiment may be used as a lower thread It can also be employed in various drive mechanisms that drive shuttles, needle bars, balances, presser bars, borers, and the like.

  In addition, an outer peripheral cam surface and an inner peripheral cam surface are formed on one surface and the other surface of the rotating plate that rotate together with the rotating shaft so that the center track of the cam follower is reversed and symmetrical with respect to the rotating plate. The lever that rotatably attaches the moving roller cam follower and the lever that rotatably mounts the roller cam follower that rolls on the inner peripheral cam surface are aligned so that the shaft cores of both roller cam followers coincide. The invention relating to the motion conversion mechanism provided with the connected swing link and taking out the reciprocating motion from the swing of the swing link is also general-purpose and various devices other than the sewing machine (for example, various looms, various machine tools, etc.) Etc.) can also be incorporated into various drive mechanisms for driving the reciprocating operation part.

It is a top view which shows the shuttle drive mechanism of the sewing machine incorporating the motion conversion mechanism of Example 1 of this invention. It is a top view which shows a mode when the shuttle drive mechanism incorporating the Example is driven. It is a fragmentary sectional view showing a sewing machine incorporating the example. It is a perspective view which shows the rotating plate and rocking | fluctuation link of the Example. It is sectional drawing which shows the rotating plate and rocking | fluctuation link of the Example. 6 is a cross-sectional view showing a sewing machine incorporating the motion conversion mechanism of Embodiment 2. FIG. (A) shows the motion conversion mechanism of Conventional Example 1, and (b) is a front view showing the motion conversion mechanism of Conventional Example 2. It is a front view which shows the motion conversion mechanism of the prior art example 3.

Explanation of symbols

9 Sewing machine 22 Shuttle for lower thread as reciprocating action part 29 Drive mechanism (shuttle drive mechanism)
40 Motion conversion mechanism 41 Rotating plate 43 Outer cam surface 45 Inner cam surface 51 Swing link 52 Lever (outer cam lever)
53 Colloidal cam follower 54 Lever (Inner circumference cam lever)
55 Roller-shaped cam follower 80 Sewing machine 81 Needle bar as reciprocating action part 82 Balance as reciprocating action part 83 Drive mechanism 84 Motion conversion mechanism 85 Rotating plate (Rotating plate for needle bar)
86 Outer cam surface 87 Inner cam surface 91 Lever (outer cam lever)
92 Lever (Inner cam lever)
101 Lever (peripheral cam lever)
102 Lever (Inner cam lever)
c Center axis p Center follower of cam follower

Claims (1)

  An outer peripheral cam surface and an inner peripheral cam surface are formed on the one surface side and the other surface side of the rotating plate rotating together with the rotating shaft so that the center track of the cam follower is reversely symmetric with respect to the rotating plate. The lever that rotatably attaches the moving roller cam follower and the lever that rotatably mounts the roller cam follower that rolls on the inner peripheral cam surface are aligned so that the shaft cores of both roller cam followers coincide. A motion conversion mechanism provided with a connected swing link and configured to take out a reciprocating motion from the swing of the swing link.

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