JP2013179999A - Sewing machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sewing machine and a method for controlling the sewing machine, which can achieve cloth feeding not affected by a rotational speed of a main output shaft of the sewing machine.SOLUTION: The sewing machine comprises a main motor driving a main shaft vertically moving a sewing needle, and a cloth feeding motor driving a cloth feeding mechanism for feeding cloth. A power transmitting mechanism included in the sewing machine transforms respective rotary operations in one direction and an opposite direction of the output shaft of the cloth feeding motor into swing motion in which the cloth feeding mechanism horizontally swings in a single reciprocative swing, to transmit the power of the cloth feeding motor to the cloth feeding mechanism. A CPU of the sewing machine acquires a rotational speed of the output shaft of the main motor (S11). The CPU refers to a correction value table to determine a correction value of the drive amount of the cloth feeding motor (S12). The cloth feeding motor can feed the cloth at a constant amount regardless of the rotational speed of the main output shaft of the main motor.

Description

  The present invention relates to a sewing machine. Specifically, the present invention relates to a sewing machine that can realize cloth feeding that is not affected by the rotational speed of the main output shaft of the sewing machine.

  There is a sewing machine in which the main shaft and the cloth feed mechanism are driven by different motors. Since the sewing machine can freely control the cloth feed amount, various patterns can be easily sewn. The sewing machine disclosed in Patent Document 1 connects a feed dog to an output shaft of a cloth feed motor that is a step motor. When the cloth feed motor reciprocates the output shaft once within a range of a predetermined angle, the feed dog reciprocates once in the horizontal direction.

JP 54-92444 A

  The conventional sewing machine has a problem that when the rotational speed of the main output shaft becomes high, the cloth feed amount becomes large due to the deflection of the cloth feed mechanism. Therefore, when sewing is performed repeatedly at a low speed and a high speed, there is a problem that the cloth feed amount varies, the stitches become uneven, and the quality of the sewing deteriorates.

  An object of the present invention is to provide a sewing machine that can realize cloth feeding that is not affected by the rotational speed of the main output shaft of the sewing machine.

  The sewing machine of the present invention has a main output shaft, and has a main motor that drives the main shaft that moves the sewing needle up and down by rotating the main output shaft, and a cloth feed output shaft, In a sewing machine including a cloth feed motor that rotates within a range of a predetermined angle and a cloth feed mechanism that feeds the cloth in a horizontal direction by driving the cloth feed motor, the number of rotations of the main output shaft of the main motor is detected. A main rotation speed detection unit, a cloth feed amount setting unit that sets a reference cloth feed amount that is a cloth feed amount when the cloth feed mechanism feeds the cloth, and the main rotation number detected by the main rotation speed detection unit Based on the above, the reference cloth feed amount set by the cloth feed amount setting unit is corrected to set the corrected fabric feed amount, and the corrected fabric feed amount is corrected by the cloth feed amount correction unit. The cloth feed motor is driven and controlled, and the cloth feed mechanism is driven. That includes a drive control unit.

  In this sewing machine, the fabric feed amount correction unit corrects the reference fabric feed amount set by the fabric feed amount setting unit based on the rotation speed of the main output shaft of the main motor detected by the main rotation number detection unit, and corrects the cloth feed amount. Therefore, even if the cloth feed amount varies due to the bending of the cloth feed mechanism, the stitches can be prevented from becoming uneven. Therefore, the sewing machine improves the quality of the seam.

  The sewing machine includes a correction value storage unit that stores a corrected fabric feed amount corresponding to the rotation speed of the main output shaft, and the fabric feed amount correction unit stores the corrected fabric feed amount stored in the correction value storage unit. The corrected cloth feed amount may be set by correcting the reference cloth feed amount with reference to the cloth feed amount. In this case, the sewing machine can correct the cloth feed amount after correction corresponding to the rotational speed of the main output shaft in the correction value storage unit, thereby correcting the cloth with the optimum correction amount.

  The cloth feed amount correction unit may calculate and set the corrected cloth feed amount based on the reference cloth feed amount and a predetermined correction coefficient. In this case, since the sewing machine calculates the reference cloth feed amount and a predetermined correction coefficient corresponding to the rotation speed of the main output shaft, it is necessary to store a large number of cloth feed amounts in the correction value storage unit in advance. In this way, a more detailed correction amount can be set and corrected.

  The sewing machine includes a correction value input unit that inputs the correction coefficient, and the cloth feed amount correction unit corrects the reference cloth feed amount based on the correction coefficient that is input by the correction value input unit. You may make it set quantity. In this case, since the sewing machine can arbitrarily adjust the correction amount, the correction amount according to the operator's desire can be set.

The perspective view of the sewing machine 1. FIG. FIG. 3 is an enlarged perspective view in the vicinity of a sewing needle 8 and a needle plate 15. The perspective view which looked at the cloth feed motor 23, the cloth feed mechanism 32, and the power transmission mechanism 35 from diagonally left rear. FIG. 6 is a perspective view of the cloth feed motor 23, the cloth feed mechanism 32, and the power transmission mechanism 35 in a state where the cloth feed output shaft 24 is at an intermediate position in the rotation range. FIG. 6 is a perspective view of the cloth feed motor 23, the cloth feed mechanism 32, and the power transmission mechanism 35 in a state where the cloth feed output shaft 24 is at the front end of the rotation range. FIG. 6 is a perspective view of the cloth feed motor 23, the cloth feed mechanism 32, and the power transmission mechanism 35 in a state where the cloth feed output shaft 24 is at the rear end of the rotation range. FIG. 2 is a block diagram showing an electrical configuration of the sewing machine 1. The figure which shows the basic table 101 of the cloth feed amount and the drive amount. The figure which shows the correction value table 102 of cloth feed amount and drive amount. 6 is a flowchart of a cloth feed amount setting process executed by the sewing machine 1; The flowchart of a 1st cloth feed amount correction process. The flowchart of the 2nd cloth feed amount correction process. The flowchart of a worker correction process. Display screen for worker correction processing.

  Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. The configuration of the sewing machine 1 will be described with reference to FIGS. The upper side, lower side, right side, left side, front side, and rear side of FIG. 1 are the upper side, lower side, right side, left side, front side, and rear side of the sewing machine 1, respectively.

  The sewing machine 1 includes a bed 2, a pedestal 3, and an arm 4. The bed part 2 is a foundation of the sewing machine 1. The bed 2 is mounted from above on a recess (not shown) on the upper surface of the table 20. The pedestal 3 extends vertically upward from the right end of the bed 2. The arm portion 4 extends leftward from the upper end of the pedestal column portion 3. The arm part 4 faces the upper surface of the bed part 2. The arm portion 4 is provided with a presser foot 17 below the left end portion. The arm portion 4 holds a needle bar 7 therein. The needle bar 7 has a sewing needle 8 (see FIG. 2) attached to the lower end. The needle bar 7 and the sewing needle 8 reciprocate up and down as the main motor 13 is driven. The arm portion 4 includes a balance 9 in front of the left end portion. The balance 9 moves up and down in conjunction with the needle bar 7. The arm unit 4 includes an operation unit 10 at the top. The operation unit 10 includes a liquid crystal panel 11 on the front surface. The operator operates the operation unit 10 while looking at the liquid crystal panel 11 and inputs various instructions to the sewing machine 1.

  The sewing machine 1 includes a control device 30 on the lower surface of the table 20. The control device 30 is connected to a stepping pedal 22 via a rod 21. The operator operates the pedal 22 to the toe side or the heel side. The control device 30 controls the operation of the sewing machine 1 according to the operation direction and the operation amount of the pedal 22.

  The pedestal 3 has a main motor 13 at the upper right side. The arm portion 4 includes a main shaft 14 inside. The main shaft 14 extends in the left-right direction inside the arm portion 4 in a rotatable state. The right end of the main shaft 14 is connected to the main motor 13. The left end of the main shaft 14 is connected to a needle bar vertical movement mechanism (not shown). The main motor 13 drives the main shaft 14 to move the needle bar 7 and the balance 9 up and down.

  As shown in FIG. 2, the bed portion 2 includes a needle plate 15 at the upper left end. The needle plate 15 has a needle hole 18 in a substantially central portion. The lower end of the sewing needle 8 passes through the needle hole 18 when lowered. The needle plate 15 is provided with a feed dog hole 19 on each of the left, rear and right sides of the needle hole 18. The feed dog hole 19 is a rectangular hole that is long in the front-rear direction. The bed 2 has a hook mechanism (not shown), a cloth feed motor 23 (see FIGS. 3 to 7), a cloth feed mechanism 32 (see FIGS. 3 to 6), and a power transmission mechanism 35 (see FIG. 3) below the needle plate 15. To FIG. 6).

  The cloth feed motor 23, the cloth feed mechanism 32, and the power transmission mechanism 35 will be described with reference to FIG. The upper side, the lower side, the left rear side, the right front side, the right rear side, and the left front side of FIG. 3 are the upper side, the lower side, the right side, the left side, the front side, and the rear side of the sewing machine 1, respectively. As shown in FIG. 3, the cloth feed motor 23 is arranged on the right side of the cloth feed mechanism 32. A cloth feed output shaft 24 of the cloth feed motor 23 extends leftward from the motor body. The cloth feed motor 23 is a step motor, and can rotate the cloth feed output shaft 24 within a range of a predetermined angle. The cloth feed motor 23 moves the cloth feed mechanism 32 in the front-rear direction.

  The cloth feed mechanism 32 includes a feed base 34 and a feed dog 33. The feed base 34 is located below the needle plate 15 (see FIG. 2) and is parallel to the needle plate 15. The feed base 34 includes a feed dog 33 near the center of the upper surface. The feed dog 33 corresponds to the position of the feed dog hole 19 (see FIG. 2). The feed dog 33 is long in the front-rear direction. The length of the feed dog 33 in the front-rear direction is shorter than the length of the feed dog hole 19. The feed dog 33 is provided with irregularities on the upper part for sandwiching the cloth with the presser foot 17 (see FIG. 2).

  The power transmission mechanism 35 includes a horizontal feed shaft 36, a first arm portion 37, a working arm portion 38, a second arm portion 39, and a connection portion 40. The horizontal feed shaft 36 is rotatably held at the upper left of the cloth feed motor 23. The horizontal feed shaft 36 extends in the left-right direction. The first arm portion 37 is connected perpendicularly to the cloth feed output shaft 24. The first arm portion 37 rotates as the cloth feed output shaft 24 rotates. The working arm portion 38 is orthogonally connected to the vicinity of the right end of the horizontal feed shaft 36. The horizontal feed shaft 36 rotates as the working arm portion 38 rotates. The second arm portion 39 is connected to the tip of the first arm portion 37 and the tip of the working arm portion 38 in a rotatable state. The connecting portion 40 extends upward from the vicinity of the left end of the horizontal feed shaft 36. The connection part 40 is rotatably connected to the front end part of the feed base 34 of the cloth feed mechanism 32.

  The operation of the power transmission mechanism 35 will be described with reference to FIGS. In the following description, the axis of the cloth feed output shaft 24 is L, the axis of the connecting shaft of the first arm portion 37 and the second arm portion 39 is M, and the connecting shaft of the second arm portion 39 and the working arm portion 38 is Let N be the axis. Each of W1 to W3 in FIGS. 4 to 6 indicates the vicinity of the feed dog 33. As described above, the cloth feed motor 23 can rotate the cloth feed output shaft 24 within a range of a predetermined angle. As shown in FIG. 4, the cloth feed output shaft 24 is located at an intermediate position in the rotation range at the time when the cloth feed is started. When the cloth feed output shaft 24 is positioned at an intermediate position in the rotation range, the straight line connecting L and M (straight line LM) and the straight line connecting M and N (straight line MN) are straight in the vertical direction in a side view. Become. Therefore, the distal end portion of the working arm portion 38 (portion connected to the second arm portion 39) is located at the upper end of the movable range. When the distal end portion of the working arm portion 38 is located at the upper end, the upper end portion of the connection portion 40 is located at the front end (the right end portion in FIG. 4) of the movable range. Therefore, the cloth feed mechanism 32 is located at the front end of the movable range.

  When the cloth feed output shaft 24 rotates clockwise from the state shown in FIG. 4, the straight line LM and the straight line MN are bent. The smaller one of the angles formed by the straight line LM and the straight line MN (hereinafter referred to as “inner angle”) gradually decreases. Therefore, the tip of the working arm 38 is lowered. The horizontal feed shaft 36 rotates counterclockwise when viewed from the left side. The cloth feed mechanism 32 moves backward. As shown in FIG. 5, when the cloth feed output shaft 24 reaches one of the two end portions (front end portion) of the rotation range, the inner angles of the straight line LM and the straight line MN become minimum. The tip of the working arm 38 is located at the lower end of the movable range. Therefore, the cloth feed mechanism 32 is located at the rear end of the movable range.

  When the cloth feed output shaft 24 is reversed from the state shown in FIG. 5 and rotated counterclockwise when viewed from the left side, the inner angles of the straight line LM and the straight line MN gradually increase. Therefore, the tip part of the action arm part 38 rises. The cloth feed mechanism 32 moves forward. When the cloth feed output shaft 24 reaches an intermediate position in the rotation range, the cloth feed mechanism 32 returns to the state shown in FIG. 4 and is positioned at the front end of the movable range. When the cloth feed output shaft 24 is further rotated counterclockwise as viewed from the left side from the state shown in FIG. 4, the straight angle LM and the inner angle of the straight line LM decrease again, and the cloth feed mechanism 32 moves rearward. As shown in FIG. 6, when the cloth feed output shaft 24 reaches the rear end of the rotation range, the cloth feed mechanism 32 is located at the rear end of the movable range. As described above, every time the cloth feed output shaft 24 rotates from one end of the rotation range to the other end, the cloth feed mechanism 32 swings back and forth horizontally.

  The power of the cloth feed motor 23 is more easily transmitted to the working arm 38 when the straight line LM and the straight line MN are in a straight line. That is, the load received by the cloth feed motor 23 is smaller when the cloth feed output shaft 24 is rotating in one direction than when the rotation direction is reversed. Therefore, the sewing machine 1 according to the present embodiment smoothly feeds the cloth if the cloth feed output shaft 24 starts the cloth feed at an intermediate position (position shown in FIG. 4) in the middle of the rotation operation in one direction. be able to.

  As shown in FIGS. 3 to 6, the sewing machine 1 includes a vertical feed shaft 27 behind the cloth feed mechanism 32. The vertical feed shaft 27 extends in the left-right direction in a rotatable state. The vertical feed shaft 27 is positioned parallel to the horizontal feed shaft 36. The vertical feed shaft 27 includes a pulley 25 at the right end. The pulley 25 is connected to the main shaft 14 via a timing belt (not shown). The main shaft 14 and the vertical feed shaft 27 rotate while maintaining synchronization. The vertical feed shaft 27 includes an eccentric portion 28 at the left end. The eccentric portion 28 moves the cloth feed mechanism 32 up and down as the vertical feed shaft 27 rotates. In the sewing machine 1, the feed dog 33 and the feed base 34 reciprocate up and down once while the needle bar 7 and the sewing needle 8 reciprocate up and down once. That is, in the sewing machine 1, the vertical movement of the sewing needle 8 and the vertical movement of the feed dog 33 are mechanically synchronized.

  When the feed base 34 is raised, the feed dog 33 protrudes above the needle plate 15 from the feed dog hole 19 (see FIG. 2) and sandwiches the cloth with the presser foot 17. While the feed dog 33 is positioned above the needle plate 15, the sewing machine 1 drives the cloth feed motor 23 by an amount specified by the sewing program. Therefore, the cloth moves in the front-rear direction with the sewing needle 8 not pierced. When the feed base 34 is lowered, the feed dog 33 is positioned below the needle plate 15. If the feed dog 33 is positioned below the needle plate 15, the cloth does not move even if the feed dog 33 moves in the front-rear direction. The sewing needle 8 forms a stitch on the cloth while the feed dog 33 is positioned below the needle plate 15. As described above, the sewing machine 1 executes the driving of the cloth feeding mechanism 32 in the horizontal direction (in the present embodiment, the front-rear direction) and the driving of the sewing needle 8 with different motors. Therefore, the sewing machine 1 can freely control the amount of horizontal movement of the feed dog 33 during sewing.

  An electrical configuration of the sewing machine 1 will be described with reference to FIG. The control device 30 of the sewing machine 1 includes a CPU 44. The CPU 44 controls the sewing machine 1. The CPU 44 is connected to a ROM 45, a RAM 46, an EEPROM (registered trademark) 47, and an I / O interface (hereinafter referred to as I / O) 48 via a bus. The ROM 45 stores a cloth feed amount setting process (see FIG. 10), a first cloth feed amount correction process (see FIG. 11), a second cloth feed amount correction process (see FIG. 12), and an operator correction process (see FIG. 13). The program for executing is stored. The RAM 46 temporarily stores various values necessary for executing the program. The EEPROM 47 is a non-volatile storage device that stores a cloth feed amount / drive amount basic table 101 (see FIG. 8), a cloth feed amount / drive amount correction value table 102 (see FIG. 9), and the like.

  The I / O 48 is connected to the pedal 22 and the operation unit 10. The CPU 44 inputs the operation direction and operation amount of the pedal 22. The CPU 44 inputs an operation instruction from the operator from the operation unit 10. The operator can set a cloth feed start position, a cloth feed end position, and a cloth feed return position, which will be described later, by operating the operation unit 10. The I / O 48 is connected to the drive circuits 51-53. The drive circuit 51 drives the liquid crystal panel 11. The drive circuit 52 drives the main motor 13 in accordance with a torque command signal input from the CPU 44. The sewing machine 1 includes a main encoder 55 for detecting a rotation angle phase and a rotation speed of the main motor 13. The main encoder 55 outputs the detection result of the rotation angle phase and rotation speed of the main motor 13 to the I / O 48. The drive circuit 53 drives the cloth feed motor 23 according to the cloth feed drive signal input from the CPU 44. The cloth feed drive signal of the cloth feed motor 23 is a pulse signal. The sewing machine 1 includes a cloth feed encoder 56 for detecting the rotation angle phase and the rotation speed of the cloth feed motor 23. The cloth feed encoder 56 outputs the detection result of the rotation angle phase and the rotation speed of the cloth feed motor 23 to the I / O 48.

  The basic table 101 of the cloth feed amount and the drive amount of the cloth feed motor 23 will be described with reference to FIG. In the sewing machine 1, the cloth feed amount for forming one stitch can be set in units of 0.1 mm from 0.0 mm to 5.0 mm. In this embodiment, as an example, the number of pulses for driving the cloth feed motor 23 (hereinafter referred to as “drive amount”) for each cloth feed amount is set to (drive amount = cloth feed amount × 100). For example, when the cloth feed amount is 1.0 mm, the drive amount of the cloth feed motor 23 is 100. The driving amount of the cloth feed motor 23 is 330 when the cloth feed amount is 3.3 mm. These values are stored in the EEPROM 47 as the basic table 101 in association with the cloth feed amount of the sewing machine 1 and the number of pulses for driving the cloth feed motor 23.

  With reference to FIG. 9, the correction value table 102 of the cloth feed amount and the drive amount of the cloth feed motor 23 will be described. The correction value table 102 stores the corrected driving amount of the cloth feed motor 23 corresponding to the rotation speed of the main output shaft of the main motor 13 in the EEPROM 47 with respect to the cloth feed amount 0.0 mm to 5.0 mm. It is. When the rotation speed of the main output shaft of the main motor 13 becomes faster, the cloth feed amount becomes larger than the set value due to the bending of the cloth feed mechanism 32. The correction value table 102 stores the driving amount of the cloth feed motor 23 for correcting the deviation from the set value according to the rotational speed of the main output shaft of the main motor 13. In the correction value table 102 of FIG. 9, “0 rpm” is a correction value for “0 rpm to less than 200 rpm”. “1000 rpm” is a correction value for “1000 rpm or more and less than 1200 rpm”. “4800 rpm” is a correction value for “4800 rpm or more and less than 5000 rpm”. “5000 rpm” is a correction value for “5000 rpm or more”. The correction value may be obtained in advance by measuring the increment of the cloth feed amount by rotating the main output shaft of the main motor 13 at each rotation speed, and obtaining the set cloth feed amount based on the increment. .

  Processing executed by the sewing machine 1 of the present embodiment will be described with reference to FIGS. The CPU 44 of the sewing machine 1 executes processing according to a program stored in the ROM 45. The sewing machine 1 can execute a plurality of processes in parallel.

  The cloth feed amount setting process will be described with reference to FIG. In the cloth feed amount setting process, the sewing machine 1 sets the cloth feed start position, the cloth feed end position, and the cloth feed return position of the cloth feed mechanism 32 (specifically, the feed dog 33) according to the operation of the operation unit 10 by the operator. . The cloth feed start position is a position where the cloth feed mechanism 32 is reversed after the cloth feed return is completed and comes into contact with the cloth to start the cloth feed. The cloth feed end position is a position where the cloth feed mechanism 32 ends the cloth feed. The cloth feed return position is a position where the cloth feed mechanism 32 starts to return the cloth feed below the needle plate 15. The cloth feed amount that is the amount of movement of the feed dog 33 in the front-rear direction is determined by setting the cloth feed start position and the cloth feed end position. In the sewing machine 1, the operator sets the cloth feed start position, the cloth feed end position, and the cloth feed return position, respectively, so that the cloth feed motor drive intermediate position, the cloth feed motor drive end position, and the cloth feed position of the cloth feed output shaft 24 are set. The motor drive start position can be obtained respectively. When the power of the sewing machine 1 is turned on, the CPU 44 starts the cloth feed amount setting process.

  The CPU 44 determines whether or not the operator has input setting values for the cloth feed start position, the cloth feed end position, and the cloth feed return position from the operation unit 10 (S1). If not input (S1: NO), the CPU 44 proceeds to the determination of S6. When the operator operates the operation unit 10 to input each set value (S1: YES), the CPU 44 converts the input value into an angle of the cloth feed output shaft 24. The CPU 44 stores the converted values in the EEPROM 47 to set the cloth feed motor drive start position, the cloth feed motor drive intermediate position, and the cloth feed motor drive end position (S2 to S4). As described above, the cloth feed mechanism 32 starts the cloth feed when the cloth feed output shaft 24 is at the cloth feed motor drive intermediate position (the state shown in FIG. 4). When the cloth feed output shaft 24 is at the cloth feed motor drive start position and the cloth feed motor drive end position, the cloth feed mechanism 32 is in the state shown in FIG. 5 or FIG. The CPU 44 sets a cloth feed amount which is a distance from the cloth feed motor drive intermediate position to the cloth feed motor drive end position (S5). In the present embodiment, the cloth feed amount is represented by the actual movement amount (mm) of the cloth feed mechanism 32.

  As described above, in this embodiment, every time the cloth feed output shaft 24 rotates once in one way, the cloth feed mechanism 32 swings back and forth horizontally once. Therefore, the sewing machine 1 sets the cloth feed motor drive start position, the cloth feed motor drive intermediate position, and the cloth feed motor drive end position separately for each of the two rotational directions of the output shaft 24. The cloth feed amount may be expressed by other values such as the number of pulses of the cloth feed motor 23.

  The CPU 44 determines whether or not the operator has input an instruction to end the process (S6). If the operator has not input an instruction to end the process (S6: NO), the CPU 44 returns the process to the determination of S1. When the operator inputs an end instruction (S6: YES), the CPU 44 ends the cloth feed amount setting process.

  A first cloth feed amount correction process that is a first embodiment of the cloth feed amount correction process will be described with reference to FIG. In the first cloth feed amount correction process, the sewing machine 1 acquires the rotation speed (number of revolutions / minute) of the main output shaft of the main motor 13, and refers to the correction value table 102 for the drive amount of the cloth feed motor 23. The cloth feed motor 23 is controlled. When the power of the sewing machine 1 is turned on, the CPU 44 starts the first cloth feed amount correction process.

  The CPU 44 acquires the current rotation speed of the main output shaft of the main motor 13 from the main encoder 55 and stores it in the RAM 46 (S11). The CPU 44 refers to the correction value table 102 shown in FIG. 9 and determines the corrected driving amount of the cloth feeding motor 23 with respect to the cloth feeding amount set in S5 of FIG. 10 (S12). For example, when the cloth feed amount set in S5 of FIG. 10 is 1.0 and the output shaft rotation speed acquired from the main encoder 55 in S11 is 5000 rpm, the corrected drive amount of the cloth feed motor 23 is 95 pulses. It becomes. When the rotation speed of the output shaft is 4400 rpm, the corrected driving amount of the cloth feed motor 23 is 96 pulses. The driving amount of the cloth feed motor 23 when the rotation speed of the main output shaft of the main motor 13 is 0 rpm or more and less than 600 rpm is a basic 100 pulses.

  The CPU 44 controls the cloth feed motor 23 through the drive circuit 53 with the corrected drive amount determined in the process of S12 (S13). Therefore, the cloth feed motor 23 can feed the cloth in a constant amount regardless of the rotation speed of the main output shaft of the main motor 13. The first cloth feed amount correction process ends when the power of the sewing machine 1 is turned off.

  Next, the second cloth feed amount correction process which is a second embodiment of the cloth feed amount correction process will be described with reference to FIG. In the first cloth feed amount correction process, the sewing machine 1 acquires the rotational speed (number of revolutions / minute) of the main motor 13 and refers to the drive amount correction value table 102 of the cloth feed motor 23 to correct the drive amount after correction. It was determined. In the second cloth feed amount correction process, the corrected drive amount is calculated by calculation using a correction coefficient with respect to the reference drive amount of the cloth feed motor 23. When the power of the sewing machine 1 is turned on, the CPU 44 starts the second cloth feed amount correction process.

The CPU 44 obtains the current rotation speed of the main output shaft of the main motor 13 from the main encoder 55 and stores it in the RAM 46 (S21). The CPU 44 calculates the corrected driving amount of the cloth feed motor 23 (S22). Since the CPU 44 calculates the reference drive amount by the cloth feed amount × 100, the corrected drive amount based on the rotation speed of the main output shaft of the main motor 13 is a correction coefficient 1− (number of rotations / 100,000). And is calculated by the following equation (S22). “Rotation speed” in the equation is the rotation speed of the output shaft of the main motor 13.
Drive amount = (feed amount × 100) × (1− (revolution number / 100000))
For example, when the rotation speed acquired from the main encoder 55 in S21 is 5000 rpm and the cloth feed amount set in S5 in FIG. 10 is 1.0, the corrected drive amount is
“1.0 × 100 × (1− (5000/100000)) = 100 × (1−0.05) = 95”.

  The CPU 44 controls the cloth feed motor 23 via the drive circuit 53 with the corrected drive amount determined in the process of S22 (S23). Therefore, the cloth feed motor 23 can feed the cloth in a constant amount regardless of the rotation speed of the main output shaft of the main motor 13. The second cloth feed amount correction process ends when the power of the sewing machine 1 is turned off.

  Next, an operator correction process that is a third embodiment of the cloth feed amount correction process will be described with reference to FIGS. In the worker correction process, the worker directly inputs a correction coefficient for correcting the driving amount of the cloth feed motor 23 by operating the operation unit 10 (see FIGS. 1 and 7). When the worker operates the operation unit 10 to start the worker correction process, the CPU 44 displays the screen shown in FIG. 14 on the liquid crystal panel 11 (S50). In the present embodiment, the reference correction coefficient displayed on the liquid crystal panel 11 is “1.000”.

  The CPU 44 determines whether or not the plus key 111 has been pressed (S51). If the plus key 111 has not been pressed (S51: NO), the CPU 44 proceeds to S56. When the plus key 111 is pressed (S51: YES), the CPU 44 adds 0.001 to the current correction coefficient (S52). That is, the correction coefficient is “1.001”. The CPU 44 starts a timer (not shown) at the same time that the plus key 111 is pressed. The CPU 44 determines whether or not the pressing state of the plus key 111 is continued (S53). When the pressed state of the plus key 111 continues for 1 second or longer (S53: YES, S54: YES), the CPU 44 adds 0.01 to the current correction coefficient (S55). That is, the correction coefficient is “1.011”. The CPU 44 returns the process to S53. When the pressed state of the plus key 111 has not continued for more than 1 second (S53: YES, S54: NO), the CPU 44 returns the process to S53. When the pressed state of the plus key 111 is not continued, that is, when the worker releases the plus key 111 (S53: NO), the CPU 44 returns the process to S51.

The CPU 44 determines whether or not the minus key 112 has been pressed (S56). When the minus key 112 is not pressed (S56: NO), the CPU 44 shifts the process to S61. When the minus key 112 is pressed (S56: YES), the CPU 44 subtracts 0.001 from the current correction coefficient (S57). That is, the correction coefficient is “0.999”. The CPU 44 starts a timer (not shown) simultaneously with the depression of the minus key 112. The CPU 44 determines whether the pressed state of the minus key 112 is continued (S58). When the pressed state of the minus key 112 is not continued, that is, when the worker releases the minus key 112 (S58: YES), the CPU 44 returns the process to S51. When the pressed state of the minus key 112 continues for one second or longer (S58: YES, S59: YES), the CPU 44 subtracts 0.01 from the current correction coefficient (S60). That is, the correction coefficient is “0.989”. The CPU 44 returns the process to S58. When the pressed state of the minus key 112 has not continued for 1 second or longer (S58: YES, S59: NO), the CPU 44 returns the process to S58. When the pressed state of the minus key 112 is not continued, that is, when the worker releases the minus key 112 (S58: NO), the CPU 44 returns the process to S51.

  The CPU 44 determines whether or not the enter key 113 has been pressed (S61). When the confirmation key 113 is not pressed (S61: NO), the CPU 44 returns the process to S51. When the enter key 113 is pressed (S61: YES), the CPU 44 stores the current correction coefficient, for example, “1.011” or “0.989” in the EEPROM 47 (S62).

  The CPU 44 calculates the driving amount of the cloth feed motor 23 (S63). For example, when the cloth feed amount set in S5 of FIG. 10 is “1.0” and the correction coefficient is “1.011”, the drive amount is 1.0 × 100 × 1.011 = 101.1. The driving amount after correcting the cloth feed motor 23 by rounding off the decimal part is 101 pulses. Further, when the amount of cloth feed is “1.0” and the correction coefficient is “0.989”, since the driving amount = 1.0 × 100 × 0.989 = 98.9, the decimal part is rounded down, The corrected driving amount of the cloth feed motor 23 is 98 pulses. It should be noted that the driving amount of the cloth feed motor 23 after the calculation may be rounded up or rounded off. The CPU 44 ends the process. As described above, in the operator correction process according to the third embodiment, the operator can set the correction coefficient for the driving amount of the cloth feed motor 23. Therefore, the correction coefficient depends on the type of cloth sewn by the sewing machine 1. Can be changed to keep the cloth feed amount constant.

  In the above-described embodiment, the main encoder 55 and the CPU 44 that executes the processes of S11 and S21 are examples of the “main rotational speed detection unit” of the present invention. The CPU 44 that executes the process of S5 is an example of the “cloth feed amount setting unit” in the present invention. The CPU 44 that executes the processes of S12 and S22 is an example of the “cloth feed amount correcting unit” in the present invention. The CPU 44 and the drive circuit 53 are an example of the “drive control unit” in the present invention. The plus key 111, the minus key 112, and the confirmation key 113 are examples of the “correction value input unit” of the present invention. The EEPROM 47 is an example of the “correction value storage unit” in the present invention.

  The present invention is not limited to the above embodiment, and various modifications can be made. For example, in the operator correction process, the correction coefficient is increased or decreased with the plus key 111 and the minus key 112, but a numerical value may be directly input. Instead of the correction coefficient, the corrected driving amount of the cloth feed motor 23 may be directly input.

DESCRIPTION OF SYMBOLS 1 Sewing machine 7 Needle bar 8 Sewing needle 10 Operation part 13 Main motor 14 Main shaft 15 Needle plate 22 Pedal 23 Cloth feed motor 24 Cloth feed output shaft 32 Cloth feed mechanism 33 Feed dog 35 Power transmission mechanism 44 CPU
45 ROM
47 EEPROM
55 Main encoder 56 Cloth feed encoder 101 Basic table 102 Correction value table 111 Plus key 112 Minus key 113 Confirm key

Claims (4)

A main motor that has a main output shaft and drives the main shaft to move the sewing needle up and down by rotating the main output shaft;
A cloth feed motor having a cloth feed output shaft and rotating the cloth feed output shaft within a range of a predetermined angle;
In a sewing machine provided with a cloth feed mechanism for feeding cloth in a horizontal direction by driving the cloth feed motor,
A main rotational speed detector for detecting the rotational speed of the main output shaft of the main motor;
A cloth feed amount setting section for setting a reference cloth feed amount that is a cloth feed amount when the cloth feed mechanism feeds the cloth;
Based on the main rotation speed detected by the main rotation speed detection unit, the cloth feed amount correction unit that corrects the reference cloth feed amount set by the cloth feed amount setting unit and sets a correction cloth feed amount;
A sewing machine comprising: a drive control unit that drives and controls the cloth feed motor so as to achieve the corrected cloth feed amount corrected by the cloth feed amount correction unit. A correction value storage unit that stores the corrected cloth feed amount corresponding to the rotation speed of the main output shaft;
The cloth feed amount correcting unit refers to the corrected fabric feed amount stored in the correction value storage unit, corrects the reference fabric feed amount, and sets the corrected fabric feed amount. Item 2. The sewing machine according to Item 1.   The sewing machine according to claim 1, wherein the cloth feed amount correction unit calculates and sets the correction cloth feed amount based on the reference cloth feed amount and a predetermined correction coefficient. A correction value input unit for inputting the correction coefficient;
The sewing machine according to claim 3, wherein the cloth feed amount correction unit corrects the reference cloth feed amount based on the correction coefficient input by the correction value input unit and sets the correction cloth feed amount.

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