JP4379221B2 - Sewing machine and control method thereof - Google Patents

Description

  The present invention relates to a sewing machine including a pulse motor and a control method thereof.

Conventionally, there are many sewing machines provided with a pulse motor for driving an object to be driven. For example, in an embroidery sewing machine, a frame holder is provided as an object to be driven, an embroidery frame that holds a work cloth is attached to the frame holder, and a pulse motor for driving the frame holder is provided. Yes. By this pulse motor, the frame holder is accurately moved to the target position together with the embroidery frame holding the work cloth. Then, the embroidery pattern set by the user is accurately sewn by the embroidery sewing machine (see, for example, Patent Document 1).
JP-A-6-86591

  Conventionally, the embroidery sewing machine is provided with a detector for detecting the amount of rotation of the pulse motor, and the actual amount of rotation of the pulse motor is detected. During driving of the pulse motor, the control device performs feedback control of the pulse motor by comparing a drive pulse for driving the pulse motor with a pulse corresponding to the detected rotation amount. Therefore, even if some external force is applied to the pulse motor during the drive of the pulse motor, the control device controls the output of the drive pulse by feedback control to prevent the pulse motor from stepping out. Yes.

However, it is normal that the control device does not perform the control as described above immediately after the drive of the pulse motor is stopped or during the stop. For this reason, there is a problem that the pulse motor is stepped out if the pulse motor is deviated from the target stop position by applying an external force to the pulse motor immediately after stopping the driving of the pulse motor.
The present invention has been made in view of the above circumstances, and an object of the present invention is to perform control for preventing the step-out of the pulse motor by detecting the amount of movement of the drive target portion even when the pulse motor is stopped. It is an object to provide a sewing machine that can be used and a control method thereof.

  The invention described in claim 1 is a sewing machine including a pulse motor that drives a drive target part of the sewing machine, a drive part that drives the pulse motor, and a control unit that controls the pulse motor via the drive part. Movement amount detection means for detecting the movement amount of the drive object is provided, and the control means is based on the target position of the drive object portion and the movement amount detected by the movement amount detection means when the pulse motor is stopped. Obtain the difference from the current position, and control the pulse motor to bring the target position closer to the current position and return the current position to the stop position so that the difference is less than the step-out limit value of the pulse motor. It is characterized by.

  The invention according to claim 2 is characterized in that the movement amount detecting means is constituted by an encoder for detecting a rotation amount of a pulse motor.

  According to a third aspect of the present invention, there is provided input means for inputting the step-out limit value.

  The invention according to claim 4 is characterized in that the pulse motor drives a work cloth moving means as a drive target portion.

  The invention according to claim 5 is characterized in that the pulse motor drives a cloth feeding means as a drive target portion.

  The invention according to claim 6 is characterized in that the pulse motor drives a cloth presser as a drive target portion.

  The invention according to claim 7 is characterized in that the pulse motor moves the sewing needle up and down as a driving object.

  The invention according to claim 8 is a control method comprising: a pulse motor for driving a drive target portion of a sewing machine; and a drive portion for driving the pulse motor, wherein the pulse motor is controlled via the drive portion. A step of obtaining a difference between the target position of the drive target unit and the current position based on the movement amount of the drive target unit detected by the movement amount detecting means in the stopped state, and the difference is a step-out limit value of the pulse motor. And a step of controlling the pulse motor so as to bring the target position closer to the current position, and a step of controlling the pulse motor so as to return the current position to the stop position. .

  According to the first aspect of the present invention, the pulse motor is arranged such that the target position is brought close to the current position so that the difference between the target position and the current position is less than the step-out limit value, and then the current position is returned to the stop position. Therefore, even when the pulse motor is stopped, feedback control of the pulse motor can be performed. Therefore, even when there is a possibility of causing a step-out due to an external force applied in the pulse motor drive stop state, this can be prevented.

  According to the invention described in claim 2, since the encoder used in the motor control is used as the movement amount detecting means, it is not necessary to newly provide a detection sensor for detecting the movement of the frame or the like.

  According to the invention described in claim 3, since the step-out limit value can be changed by the input means, the step-out limit value is changed by changing the pulse motor or changing the frame to change the weight. However, it can easily respond to the control and control it.

  According to the invention of claim 4, when the operator pulls out the work cloth after finishing the work, it can be returned to the work end state without being stepped out even if the work cloth moving means moves, so that the next work can be performed. There will be no hindrance.

  According to the fifth aspect of the present invention, the same effect as that of the fourth aspect of the present invention can be obtained even when applied to the cloth feeding means.

  According to the sixth aspect of the present invention, the same effect as that of the fourth aspect of the present invention can be obtained even when applied to the cloth pressing means.

  According to the seventh aspect of the invention, the same effect as that of the fourth aspect of the invention can be obtained even when applied to a sewing needle.

  According to the eighth aspect of the invention, the same effect as that of the first aspect of the invention can be obtained.

(First embodiment)
The first embodiment of the present invention will be described below with reference to FIGS.
This embodiment is an example in which the present invention is applied to an embroidery multi-needle sewing machine having a frame holder on which an embroidery frame is mounted. This multi-needle sewing machine includes a pulse motor for driving a frame holder on which an embroidery frame is mounted in the X direction and the Y direction. Here, the left-right direction of the multi-needle sewing machine M is the X direction, and the front-rear direction is the Y direction.

  First, the overall configuration of the multi-needle sewing machine M will be described with reference to FIG. The support leg 1 mounted on a mounting table (not shown) is formed in a substantially U shape with the front side opened. A leg column portion 2 is provided to extend upward at a curved portion on the rear side of the support leg 1, and an arm portion 3 is provided to extend forward at the upper end of the leg column portion 2. A needle bar case 4 is provided at the distal end of the arm 3 so as to be movable in the left-right direction (X direction). The support leg 1 is integrally provided with a cylinder bed 5 extending forward from the rear. The support leg 1 is provided with a carriage (corresponding to a driving object, work cloth moving means) 6 that moves in the Y direction. The carriage 6 is provided with a frame holder (corresponding to a driving object, work cloth moving means) 20 positioned above the cylinder head 5, and the frame holder 20 is moved together with the carriage 6. The arm unit 3 is provided with an operation panel 8 as input means, and the operation panel 8 is provided with a touch panel 8a. The user can perform various operations via the touch panel 8a. The multi-needle sewing machine M includes a control device 40 (see FIG. 3) that controls the entire multi-needle sewing machine M.

At the lower end of the needle bar case 4, six needle bars (not shown) to which the sewing needles 10 are attached are provided, and the balance 11 is arranged so as to correspond to the needle bars. A thread tensioner base 12 is provided at the upper end of the needle bar case 4, and six thread tensioners 13 are disposed on the thread tensioner base 12.
Although not shown, a driving force transmission mechanism, a sewing needle up / down driving mechanism, a balance swinging mechanism, a needle bar balance switching mechanism, and the like are provided in the arm unit 3. The driving force transmission mechanism is configured to transmit the driving force of the sewing machine motor 50 (see FIG. 3) provided in the pedestal portion 2 to the sewing needle up / down driving mechanism and the balance swinging mechanism. The swing mechanism is configured to drive the sewing needle 10 and the balance 11 with the driving force transmitted from the driving force transmission mechanism, and the needle bar balance switching mechanism is a needle bar case drive motor 55 (see FIG. 3). The needle bar case 4 is moved in the left-right direction by the driving force of () to switch the desired needle bar and the balance 11 to a position where the driving force can be transmitted. Therefore, detailed description is omitted.

  A pair of thread spool bases 14 on which a total of six thread spools (not shown) can be placed are provided in the rear half of the upper surface of the arm section 3, and a guide mechanism 15 is provided so as to correspond to the thread spool bases 14. Is provided. An upper thread extending from a thread spool (not shown) is supplied to the sewing needle 10 via the guide mechanism 15, the thread tensioner 13 and the balance 11. The thread spool base 14 and the guide mechanism 15 are configured to be switchable from the storage position shown in FIG. 1 to a position opened in a V shape rearward with the front portion as a fulcrum.

  As shown in FIG. 2, the carriage 6 is provided with an X-direction carriage 21 on which a frame holder 20 is mounted so as to be movable in the X direction, and further provided with an X-direction drive motor 22 which is a pulse motor. The driving force of the direction drive motor 22 is transmitted to the X direction carriage 21 via the timing belt 23. As shown in FIG. 1, the carriage 6 is provided with guide legs 24, which include a Y-direction drive motor 53 (see FIG. 3) that is a pulse motor provided on the pedestal 2. Driving force is transmitted.

  The X-direction drive motor 22 is of a double shaft type. The output belt 25 extending above the X-direction drive motor 22 is covered with a timing belt 23, while the output shaft 25 extending below the X-direction drive motor 22 is connected to an encoder 57 (FIG. 3). Reference) is provided.

  The encoder 57 is for detecting the actual rotation amount of the X-direction drive motor 22. Although not shown, the encoder 57 is configured to include a disk rotatably provided on the output shaft 25, and a detector having a light emitting part and a light receiving part opposed to each other with the disk interposed therebetween. Slits are formed at appropriate intervals in the circumferential direction. The encoder 57 outputs a detected signal (pulse) to the control device 40 when the light emitted from the light emitting section passes through the slit of the disk and is detected by the light receiving section.

  The timing belt 23 is stretched between the output shaft 25 and the rotation shaft 26 of the X direction drive motor 22. The timing belt 23 is connected to a connecting member 27, and the connecting member 27 is connected to the X direction carriage 21 at two locations. Accordingly, the driving force of the X direction drive motor 22 is transmitted to the X direction carriage 21 via the timing belt 23, and the frame holder 20 is moved in the X direction together with the X direction carriage 21. Therefore, the detected rotation amount of the encoder 57 has a correlation with the movement amount in the X direction of the frame holder 20 that is the drive target unit. As a result, the encoder 57 detects the movement amount in the X direction of the frame holder 20. Become.

  The guide leg 24 is disposed in a guide groove 28 formed in the support leg 1 so as to be movable along the guide groove 28. Accordingly, the driving force of the Y-direction drive motor 53 is transmitted to the carriage 6 via the guide legs 24, and the frame holder 20 provided on the carriage 6 together with the carriage 6 is moved in the Y direction. The output shaft of the Y direction drive motor 53 is provided with an encoder 58 (see FIG. 3) having the same configuration as the encoder 57 serving as a movement amount detecting means attached to the X direction drive motor 22. Therefore, as a result, the encoder 58 detects the amount of movement of the frame holder 20 in the Y direction.

  As shown in FIG. 2, an embroidery frame 29 that holds a work cloth is attached to the frame holder 20. The frame holder 20 is provided with a pair of left and right arm portions 30a and 30b. The left arm portion 30 a is configured to be movable in the left-right direction so as to correspond to the size of the embroidery frame 29. Therefore, both ends of the embroidery frame 29 are supported by the right arm portion 30b and the left arm portion 30a moved to a position where the embroidery frame 29 can be attached.

  When embroidery sewing is performed by the multi-needle sewing machine M, the work cloth is moved by the X-direction drive motor 22 and the Y-direction drive motor 53. The driving force of the sewing machine motor 50 is transmitted to the needle bar via a driving force transmission mechanism, a sewing needle up / down driving mechanism, etc., and the sewing needle 10 and the balance 11 are swung up and down together with the needle bar. Further, a shuttle (not shown) provided on the cylinder bed 5 is driven in accordance with the movement of the sewing needle 10 and the balance 11. In this case, the hook operates to capture the upper thread from the sewing needle 10 and entangle it with the lower thread. Therefore, embroidery sewing is performed on the work cloth.

  Next, a control system of the multi-needle sewing machine M will be described with reference to FIG. As shown in FIG. 3, the control device 40 governs overall control of the multi-needle sewing machine M. The control device 40 constitutes a microcomputer including a computer 45 including a CPU 41, a ROM 42, a RAM 43, and a bus 44 connecting them, an input / output interface 46 for inputting / outputting to / from the computer 45, and the like.

  The input / output interface 46 includes a drive circuit 51 for driving the sewing machine motor 50, a drive circuit 56 for driving the needle bar case drive motor 55, and a drive circuit 52 for driving the X-direction drive motor 22 (corresponding to a drive unit). ) And a drive circuit 54 for driving the Y-direction drive motor 53 and the like. The input / output interface 46 is connected to the operation panel 8, encoders 57 and 58, and the like.

  The CPU 41 calculates the current position of the drive motors 22 and 53 based on signals (number of pulses) representing the rotation amounts of the drive motors 22 and 53 detected by the encoders 57 and 58, and particularly in the current position. The calculation of the drive motors 22 and 53 based on the calculation for separately obtaining the stop position as the stop position when the drive motors 22 and 53 are driven and the number of drive pulses output from the drive circuits 52 and 54 to the drive motors 22 and 53 Calculations for obtaining the target position, calculations for obtaining a difference between the current position and the target position, and the like are performed.

In the ROM 42, a drive motor control program for controlling the drive motors 22, 53, a step-out limit value of the drive motors 22, 53, and the like are recorded in advance so as to be readable.
The RAM 43 outputs the current position based on the rotation amount corresponding to the number of pulses detected from the encoders 57 and 58, the stop position where the drive motors 22 and 53 are stopped, and the drive motors 22 and 53. Various data such as a target position based on the number of pulses to be stored is stored.

  Next, before explaining the drive motor control program, the relationship between the maximum rotation torque and the difference between the rotation angle of the rotor and the excitation coil, which is a necessary relationship for controlling the pulse motor with the maximum torque An example of a four-phase pulse motor PM as shown in FIG. 6 will be described with reference to FIG. The pulse motor PM includes four coils C1, C2, C3, and C4 and a rotor RT that is a permanent magnet. The rotor RT is rotated around the rotation axis RS by the excited coils C1, C2, C3, and C4.

  Each curve shown in the graph of FIG. 7 shows the relationship between the rotation angle of the rotor RT and the output torque when drive pulses are output to the coils C1, C2, C3, and C4. In the following description, when a drive pulse is output to the coils C1, C2, C3, C4, the direction of the current flowing through the coils C1, C2, C3, C4 is “N” to the coils C1, C2, C3, C4. ”And“ S ”, it is assumed that an attractive force acts between the N pole of the rotor RT and the coils C1, C2, C3, and C4 from which the drive pulse is output. In addition, the position of the rotor RT shown in FIG.

  At the position of the rotor RT shown in FIG. 6, since the drive pulse is output to the coil C1, the torque acting on the rotor RT is “0”. Next, when the first drive pulse is output to the coil C2, the north pole of the rotor RT is pulled to the coil C2. Therefore, the rotor RT is rotated counterclockwise around the rotation axis RS in plan view. Next, when the rotor RT is rotated by 45 °, the torque acting on the rotor RT decreases as shown by the curve C2 in FIG. Therefore, the coil C2 is demagnetized and the second drive pulse is output to the coil C3. When the drive pulse is output to the coil C3, the torque acting on the rotor RT increases again as shown by the curve C3 in FIG. Next, when the rotation angle of the rotor RT becomes 135 °, the torque acting on the rotor RT becomes small. For this reason, the coil C3 is demagnetized and the third pulse is output to the coil C4. When the drive pulse is output to the coil C4, the torque acting on the rotor RT increases as shown by the curve C4 in FIG. After that, the output of the pulse motor PM is maintained at a substantially maximum torque by repeating the same manner as described above.

  As described above, when the angle difference of 135 ° is maintained between the coil from which the pulse is output and the rotor RT, the rotor RT can be rotated while the output of the pulse motor PM is maintained at the substantially maximum torque. . That is, since the pulse motor PM is formed by the four coils C1, C2, C3, and C4, one drive pulse corresponds to a rotation angle of 90 °. When the deviation between the number of drive pulses output to the coils C1, C2, C3 and C4 and the number of drive pulses corresponding to the rotation angle of the rotor RT is maintained at 1.5 pulses (set deviation). The output of the pulse motor PM is always maintained at a substantially maximum torque.

The operation of the present embodiment will be described below with reference to FIGS.
First, the embroidery sewing machine will be described from the state where the user is performing normal embroidery and sewing.
FIG. 4 shows a process executed by the drive motor control program. This drive motor control program is a process for controlling the X direction drive motor 22 and the Y direction drive motor 53 independently of each other. Now, the details of the drive motor control program will be described by taking the X direction drive motor 22 as an example. Similarly, the Y direction drive motor 53 is similarly controlled. In FIG. 4, the CPU 41 determines whether the X-direction drive motor 22 (Y-direction drive motor 53) is in a stopped state (S1). Here, since embroidery / sewing is being performed by the user, the CPU 41 determines that the drive motor 22 (53) is not stopped (S1: NO), and shifts to drive motor drive processing (S5). This drive motor drive process is performed when the user performs embroidery, and is a process for performing control during drive of the drive motor 22 (53).

In this drive motor processing, the first pulse number P ₁ is the drive pulse number output to the X-direction drive motor 22 by the control device 40 via the drive circuit 52. The second pulse number P ₂ is a pulse number (indicating the current position) obtained by converting the detected pulse number representing the actual rotation amount of the X-direction drive motor 22 detected by the encoder 57 into the drive pulse number of the X-direction drive motor 22. It is.
The end pulse number Pa is the number of pulses for indicating the target position by moving by one stitch (indicating the target position). When the first pulse number P ₁ reaches the end pulse number Pa, the output of the drive pulse is ended. .

The CPU 41 calculates the deviation between the first pulse number P ₁ and the second pulse number P _2, and controls the drive pulse output timing so that this deviation is within the set deviation. Then, the CPU 41 stops outputting the drive pulse when the first pulse number P ₁ reaches the end pulse number Pa, and when the second pulse number P ₂ coincides with the first pulse number P ₁ , The drive motor 22 stops (corresponding to a stop position).

  Next, as the case where the pulse motor driving process is completed as the embroidery / sewing by the user is finished without any problem, as shown in FIG. 5A, the stop position, the target position and the current position are all in the same position. After the drive motor drive process is completed as the user completes the normal stop state, which is a certain stop state, and the embroidery / sewing is completed by the user, some load (external force or inertial force of the drive motor 22 (53)) is applied to the drive motor 22 (53). 5), as shown in FIG. 5 (b), a deviation occurs between the stop position and the target position and the current position. However, if the load is eliminated, the characteristics of the drive motor 22 (53) are obtained. A description will be given of the abnormal stop state 1 that is a stop state in which a deviation that can be restored is generated (due to detent torque or holding torque). The detent torque is a force that works to maintain the position by attracting each other by magnetic attraction between the permanent magnet of the predetermined rotor and the magnetic pole of the stator even when the drive motor 22 (53) is disconnected. In other words, the holding torque is a force that works to maintain the position by attracting by the magnetic attraction between the permanent magnet of the predetermined rotor of the drive motor excited by the rated current and the excitation of the stator.

  In FIG. 4, the CPU 41 assumes that the drive motor 22 (53) is in a stopped state (S1: YES), and responds to the stop position, which is the position stopped when the pulse motor drive processing is completed, and the signal of the encoder 57 (58). It is determined whether the current positions are substantially equal (S2). Here, since it is in the abnormal stop state 1, which is a deviation enough to restore if the load applied to the drive motor 22 (53) is eliminated, the CPU 41 determines that the stop position≈the current position (S2: YES). The process is repeated (S1, S2).

In FIG. 5B, the target position and the stop position are deviated to the extent that they can be restored (due to detent torque or holding torque) due to the nature of the drive motor 22 (53). Is restored to match the target position (stop position), and the stop position, the target position, and the current position match as shown in FIG.
Subsequently, as a case where some load (external force, inertial force of itself, etc.) is applied to the drive motor 22 (53) after the drive motor drive processing is completed as the embroidery / sewing by the user is completed, FIG. As shown in FIG. 5C, a deviation occurs between the stop position and the target position and the current position, and the deviation is an abnormal state in which the deviation exceeds the step-out limit value of the drive motor 22 (53). 2 will be described.

  In FIG. 4, the CPU 41 determines that the drive motor 22 (53) is in a stop state (S1: YES), assumes that the stop position is not the current position (S2: NO), and further determines that the target position and the actual position are the step-out limit values. It is determined whether it is the following (S3). Here, since some load is applied to the drive motor 22 (53), the target position and the current position are in the abnormal stop state 2 in which the target position and the current position are shifted beyond the step-out limit value. It is determined that the difference from the current position exceeds the step-out limit value (S3: NO), and the drive motor 22 (53) is brought close to the current position so that the drive motor 22 (53) does not step out. The excitation phase is changed (S6). Here, as shown in FIG. 5D, the drive motor 22 (53) will step out unless the difference between the target position and the current position is kept within the step-out limit value. The excitation phase is changed so that the current position shifted by the load with respect to the position can be followed so that the difference between the target position and the current position is within the step-out limit value.

Thereafter, when the load acting on the drive motor 22 (53) is removed, as shown in FIG. 5E, the current position is determined by the nature of the drive motor 22 (53) (by detent torque or holding torque). And move to match the target position.
Further, the CPU 41 assumes that the drive motor 22 (53) is in the stopped state and is not yet stopped position≈current position (S1: YES, S2: NO), and further, the difference between the target position and the current position is the step-out limit value. In the following (S3: YES), a pulse is output to the drive motor 22 (53) so as to bring the target position closer to the stop position (S4). In short, the target position is set to the stop position in order to make the current position of the drive motor 22 (53) coincide with the stop position by the same control as the normal drive motor 22 (53). In this way, the CPU 41 calculates the number of pulses from the current position to the stop position, and outputs it to the drive motor 22 (53) by the calculated number of pulses, as shown in FIG. In addition, control is performed to bring the current position closer to the target position and the stop position, and finally, the stop position, the target position, and the current position all match.

  As described above, the drive motors 22 and 53 for driving the carriage 6 and the frame holder 20 of the multi-needle sewing machine M, the encoders 57 and 58 are attached to the drive motors 22 and 53, and the drive circuit 52, 54, a control device 40 for controlling the drive motors 22 and 53 is provided. The control device 40 confirms that the drive motors 22 and 53 are stopped (S1: YES), and the target positions of the drive motors 22 and 53 are determined. And the actual position based on the amount of rotation detected by the encoders 57 and 58 is judged whether or not the difference between the actual position and the step-out limit value is less than the step-out limit value (S3). A pulse is output to the drive motors 22 and 53 so as to be close to (S6), and then a pulse is output so that the target position is close to the stop position (S4).

  According to such a configuration, while the drive motors 22 and 53 are stopped, the control device 40 includes the target position corresponding to the drive pulse output from the control device 40 (CPU 41) to the drive motors 22 and 53, and the encoder 57. , 58 can be compared with the current position corresponding to the amount of rotation detected, feedback control can be performed, and if any load (external force or its own inertial force, etc.) is applied to the drive motors 22, 53. Even when there is a possibility of causing a step-out due to the addition, the control device 40 can prevent the step-out by controlling the drive motors 22 and 53 so as not to step out. The set embroidery pattern is sewn more accurately.

  Furthermore, since an encoder used in motor control is used as the movement amount detecting means, it is not necessary to newly provide a detection sensor for detecting the movement of the frame or the like.

(Second embodiment)
FIG. 8 shows a second embodiment of the present invention, and the differences from the first embodiment will be described. In the first embodiment, the configuration is applied to the embroidery sewing machine provided with the drive motors 22 and 53. However, in this embodiment, the configuration is applied to a hole sewing machine. In this case, the perforated sewing machine includes a feed base driving mechanism that feeds the work cloth through the feed base, a cloth presser that moves the cloth presser detachably attached to the lower end of the press bar up and down, A sewing mechanism for forming a hole seam on the work cloth, a cutter driving mechanism for forming a button hole by a cutter at the hole seam formed on the work cloth, and the like are provided. Here, the left-right direction of the drawing is the front-rear direction of the hole sewing machine, and the direction perpendicular to the front-rear direction is the left-right direction.

  FIG. 8 shows a feed base driving mechanism 59 and a cloth presser device 70 for a hole sewing machine. In FIG. 8, the feed base driving mechanism 59 includes a work cloth placing table 60 for installing a work cloth. The work cloth placing table 60 is provided with a groove 60a in the front-rear direction, and the groove 60a. A plate-like feed base (corresponding to a cloth feed means) 61 is arranged to be movable in the front-rear direction. A movable member 62 that is formed in a rectangular plate shape and has a hole is provided on the lower surface of the rear end portion of the feed base 61, and a communication rod 63 is inserted into the hole of the movable member 62. 63 is inserted into a hole formed in the movable member 64 disposed behind the movable member 62, and the movable members 62, 64 are moved relative to the connecting rod 63 between the movable members 62, 64. A bearing 65 for facilitating the operation and a rack gear 66 are provided. Further, a feed pulse motor 68 is disposed so as to correspond to the rack gear 66, and a pinion gear 67 is provided on the output shaft of the feed pulse motor 68. By driving the feed pulse motor 68, the feed base drive mechanism 59 can move in the front-rear direction with respect to the work cloth mounting table 60. Incidentally, on the opposite side of the output shaft where the pinion gear 67 of the feed pulse motor 68 is provided, there is a movement amount detecting means having the same configuration as the encoder 57 mounted on the X-direction drive motor 22 of the first embodiment. An encoder 69 is provided.

  The cloth presser device 70 includes a substantially arch-shaped presser arm 71, a rear end portion of which is pivotally mounted on the movable member 64 so as to be able to swing up and down. 72 (corresponding to the means) is arranged. The cloth presser 72 is connected to the presser bar 73 with a screw through a groove formed in the front-rear direction on the side surface of the front end portion of the presser arm 71, and a rolling roller 74 provided on the presser bar 73 is connected to the presser bar 73. It can move smoothly by sliding on the upper surface of the arm 71. The pressing rod 73 is connected to a pressing pulse motor 75 via a cam mechanism (detailed description is omitted). When the pressing pulse motor 75 is driven, the cloth presser 72 is driven in the vertical direction integrally with the presser bar 73 and is driven in the front-rear direction within the range of the groove formed in the presser arm 71. Is done. Note that the output shaft of the pressing pulse motor 75 is provided with an encoder 76 that is a movement amount detecting means having the same configuration as the encoder 69 mounted on the feeding pulse motor 68.

  Although not shown, the boring machine is provided with a control device. The control device includes a feed pulse motor 68 for driving the feed base drive mechanism 60 and a press pulse motor for driving the cloth presser 70. 75 are connected to each other via a drive circuit. Further, an encoder 69 for detecting the rotation amount of the feed pulse motor 68 and an encoder 76 for detecting the rotation amount of the pressing pulse motor 75 are connected to the control device.

  Then, the control device controls the feed pulse motor 68 and the pressing pulse motor 75 by the same control method as the drive motor 22 (53) of the first embodiment.

  According to such a configuration, since the present invention is applied to the hole sewing machine provided with the feed pulse motor 68 and the pressurization pulse motor 75, some load (external force, inertia force of itself, etc.) is used for feed. Even when there is a possibility of causing a step-out by applying to the pulse motor 68 or the pressing pulse motor 75, the control device controls so that the feeding pulse motor 68 or the pressing pulse motor 75 does not step out, Step-out can be prevented.

(Modification)
In the above embodiment, the step-out limit value is stored in the ROM 42 in advance. However, the step-out limit value may be set and changed through the operation panel 8 to an arbitrary value of the user. Therefore, even when the motor is replaced with a pulse motor having a different step-out limit value or the weight is changed by changing the frame, it can be easily handled and controlled.

  In the above embodiment, the sewing machine motor 50 is controlled by the control device 40. However, instead of the sewing machine motor 50, a sewing machine motor constituted by a pulse motor is used and driven by the control device 40. The same control as the motors 22 and 53 may be performed. Therefore, the sewing needle 10 becomes a drive target part of the pulse motor, and its upper and lower parts are controlled.

  In the above embodiment, when the shuttle disposed in the cylinder bed 5 is driven by a unique pulse motor, the pulse motor may be controlled in the same manner as the drive motors 22 and 53. The object to be driven in this case is a shuttle, and its rotation is controlled.

  The present invention may be applied to a staggered sewing machine. In this case, the drive target portion of the pulse motor is a sewing needle, and its swing is controlled.

Overall view of the multi-needle sewing machine showing the first embodiment of the present invention Plan view around the carriage of a multi-needle sewing machine Block diagram showing electrical configuration of multi-needle sewing machine Flowchart showing processing executed by drive motor control program Diagram showing the state of the drive motor Schematic of pulse motor coil and rotor The figure which shows the torque curve of the pulse motor when current is passed through each coil Partial view of a perforated sewing machine showing a second embodiment of the present invention

Explanation of symbols

  In the drawings, 1 is a support leg, 2 is a pedestal, 3 is an arm, 4 is a needle bar case, 5 is a cylinder head, 6 is a carriage (drive target part, work cloth moving means), and 8 is an operation panel (input). Means), 8a is a touch panel, 10 is a sewing needle, 15 is a guide mechanism, 20 is a frame holder (drive target part, work cloth moving means), 21 is an X direction carriage, 22 is an X direction drive motor, 23 is a timing belt, 24 Is a guide leg, 25 is an output shaft, 26 is a rotation shaft, 29 is an embroidery frame, 30a is a left arm, 30b is a right arm, 40 is a control device, 41 is a CPU, 42 is a ROM, 43 is a RAM, 44 is a bus, 45 is a computer, 46 is an input / output interface, 50 is a sewing machine motor, 51, 52, 54 and 56 are drive circuits, 53 is a Y-direction drive motor, 57, 58, 69 and 76 are encoders (movement amount detection) hand , 59 is a feed table drive mechanism, 60 is a work cloth placing table, 61 is a feed table (cloth feed means), 62 and 64 are movable members, 63 is a connecting rod, 68 is a pulse motor for feeding, and 70 is a cloth presser. , 71 is a pressing arm, 71a is a groove, 72 is a cloth presser (cloth presser means), 73 is a presser bar, and 75 is a pulse motor for pressing.

Claims (8)

A pulse motor for driving a drive target portion of the sewing machine;
A drive unit for driving the pulse motor;
In a sewing machine provided with a control means for controlling the pulse motor via this drive unit,
A moving amount detecting means for detecting a moving amount of the driven object is provided;
The control means obtains a difference between the target position of the drive target unit and the current position based on the movement amount detected by the movement amount detection means in the stop state of the pulse motor, and the difference is a step-out limit of the pulse motor. A sewing machine characterized by controlling a pulse motor so as to bring the target position closer to the current position so as to be less than or equal to the current value and to return the current position to the stop position.   2. The sewing machine according to claim 1, wherein the movement amount detecting means is constituted by an encoder for detecting a rotation amount of a pulse motor.   The sewing machine according to claim 1, further comprising an input unit that inputs the step-out limit value.   The sewing machine according to any one of claims 1 to 3, wherein the pulse motor drives a work cloth moving means as a drive target portion.   The sewing machine according to any one of claims 1 to 3, wherein the pulse motor drives cloth feeding means as a drive target portion.   The sewing machine according to any one of claims 1 to 3, wherein the pulse motor drives a cloth presser as a drive target portion.   The sewing machine according to any one of claims 1 to 3, wherein the pulse motor moves a sewing needle up and down as an object to be driven. A pulse motor for driving a drive target portion of the sewing machine;
A drive unit for driving the pulse motor,
In a control method for controlling a pulse motor via this drive unit,
Obtaining a difference between a target position of the drive target unit and a current position based on a movement amount of the drive target unit detected by a movement amount detection unit in a stop state of the pulse motor;
Controlling the pulse motor to bring the target position closer to the current position so that the difference is less than the step-out limit value of the pulse motor;
And a step of controlling a pulse motor so as to return the current position to the stop position.

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